Bump forming apparatus, semiconductor manufacturing apparatus and bump forming method

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a bump forming apparatus and a bump forming method for forming bumps on a land of a substrate or a pad of a chip .

【0002】

[Conventional technology]

FIG. 15 is a cross-sectional view schematically showing the configuration of a conventional bump forming apparatus (see JP-A-3-60036). The inkjet printer 121 has a head 123, and a paste chamber 124 and an air chamber 125 are provided in the head 123. The paste chamber 124 is provided with a plurality of inner nozzles 126, and the air chamber 125 is provided with outer nozzles 127 at locations facing the inner nozzle 125. On the lower surface of the paste chamber 124, a plurality of control electrodes 128 are provided in the vicinity of the inner nozzle 126. Further, on the lower surface of the air chamber 125, a plurality of common electrodes 129 are provided in the vicinity of the outer nozzle 127.

【0003】

Hereinafter, a method of forming bumps using the inkjet printer 121 shown in FIG. 15 will be described. First, the semiconductor element 130 is arranged so as to face the head 123. Specifically, a plurality of electrode pads 131 are formed in the semiconductor element 130, and the semiconductor element 130 is positioned and arranged so that each of the plurality of electrode pads 131 faces each of the plurality of outer nozzles 127. To do.

【0004】

Next, compressed air is supplied from the outside into the air chamber 125 as shown by arrow X. The air pressure of compressed air is, for example, 0.5 kg / cm.²~ Several kg / cm²Set to about. At this time, the conductor paste 122 is held in the paste chamber 124. The conductor paste 122 is composed of a metal powder, a binder, and an adhesive material. The metal powder is determined in consideration of the materials of the bump 132 and the electrode pad 131 to be formed, and for example, a powder such as solder, tin, or lead is used. The binder is used as a solvent, and volatile methyl alcohol, isopropyl alcohol, or methyl ethyl ketone is used. Further, as the adhesive material, a material having a flux action is used. The compressed air supplied into the air chamber 125 becomes an air flow Y and flows out from the outer nozzle 127 to the outside.

【0005】

Next, a voltage of about minus several 100 V is applied between the control electrode 128 and the common electrode 129. Due to the electrostatic force generated by this voltage application, a certain amount of conductor paste 122 is drawn out from the paste chamber 124 through the inner nozzle 126, the air chamber 125, and the outer nozzle 127 in this order. At this time, the air flow Y plays a role of guiding the conductor paste 122 to the outer nozzle 127 and quickly pulling out the conductor paste 122 to the outside.

【0006】

The conductor paste 122 discharged to the outside from the outer nozzle 127 flies in the form of a thin thread having a diameter of, for example, about 10 μm to several tens of μm, and adheres to the electrode pad 131 of the semiconductor element 130. FIG. 15 shows the conductor paste 122a that has begun to be discharged, the conductor paste 122b that has begun to be discharged, and the conductor paste 122c that has begun to adhere to the electrode pad 131, and finally the bump 132 is formed on the electrode pad 131. It is formed.

【0007】

[Problems to be Solved by the Invention]

However, the conventional bump forming apparatus has the following problems because the inkjet printer 121 is used and the conductor paste 122 is simply used instead of the ink.

【0008】

First, since the conductor paste 122 contains metal powder such as solder and an adhesive material, there is a problem that the conductor paste 122 is clogged with the inner nozzle 126 and the outer nozzle 127, and the discharge failure of the conductor paste 122 is likely to occur. ..

【0009】

In addition, the conductor paste 122 has a high viscosity because it contains an adhesive material, and the inner nozzle 126 has an air chamber of 125 to 0.5 kg / cm.²~ Several kg / cm²There is some pressure. Therefore, after the conductor paste 122 is once discharged from the inner nozzle 126, it takes a long time to fill the inner nozzle 126 with the conductor paste 122 again. Therefore, there is a problem that it is difficult to speed up the discharge, and there is also a problem that if the conductor paste 122 is discharged when the conductor paste 122 is not completely filled in the inner nozzle 126, the discharge amount varies. ..

【0010】

Further, since pressure is applied to the inner nozzle 126 from the air chamber 125, when the conductor paste 122 is discharged from the inner nozzle 126, the air in the air chamber 125 enters the paste chamber 124 through the inner nozzle 126. There is a problem that bubbles are generated in the conductor paste 122, and the discharge of the conductor paste 122 becomes unstable due to the bubbles.

【0011】

The present invention has been made to solve these problems, and is a bump forming apparatus capable of appropriately realizing avoidance of ejection defects, speeding up of ejection, avoidance of variation in ejection amount, and stabilization of ejection. The purpose is to obtain a bump forming method.

【0012】

[Means for solving problems]

The bump forming apparatus according to claim 1 of the present invention stores molten solder, has a first tank having an outlet for molten solder, a pipe having one end connected to the outlet, and a first tank. From a cavity that is located below and has an inflow of molten solder connected to the other end of the pipe, a nozzle that is located below the cavity and has a first opening on the bottom, and a first opening. A pressurizing element that appropriately pressurizes the molten solder in the cavity toward the first opening, a first heater that heats the first tank and the cavity, and the molten solder applied to the nozzle in order to drop the molten solder. It is provided with a static pressure control unit for keeping the static pressure at a constant value.

【0013】

Further, in the present invention, the bump forming apparatus according to claim 2 is the bump forming apparatus according to claim 1, and the pressurizing element is fixed to the diaphragm arranged in the upper part of the cavity and the upper surface of the diaphragm. The diaphragm is characterized in that it can pressurize the molten solder in the cavity in the direction of the first opening and in the direction opposite to the direction of the first opening. Is.

【0014】

Further, the bump forming apparatus according to claim 3 of the present invention is the bump forming apparatus according to claim 1, and the static pressure control unit stores solid solder and has a second opening on the bottom surface. A second tank having a portion and arranged above the first tank, a second heater provided around the second opening, and the liquid level height of the molten solder in the first tank. It has a liquid level detector for detecting the pressure and a control unit for controlling the drive of the second heater based on the detection signal from the liquid level detector.

【0015】

Further, the bump forming apparatus according to claim 4 of the present invention is the bump forming apparatus according to claim 3, and includes an inert gas introduction unit for introducing an inert gas into a second tank, and a third. It is further provided with an inert gas exhaust unit that exhausts the inert gas from the tank of 2.

【0016】

Further, the bump forming apparatus according to claim 5 of the present invention is the bump forming apparatus according to claim 3, and includes an inert gas introduction unit that introduces an inert gas into the first tank, and a third. It is further provided with an inert gas exhaust unit that exhausts the inert gas from the tank of 1.

【0017】

Further, in the present invention, the bump forming apparatus according to claim 6 is the bump forming apparatus according to claim 1, and the static pressure control unit is an inert gas that introduces an inert gas into the first tank. A gas introduction unit, a first gas flow control unit that controls the amount of inert gas flowing into the first tank from the inert gas introduction unit, and a gas in the first tank to the outside of the first tank. The gas exhaust unit to be exhausted, the second gas flow control unit that controls the amount of gas flowing out from the first tank through the gas exhaust unit, and the liquid level height of the molten solder in the first tank are detected. It has a liquid level detector and a gas pressure control unit that controls driving of at least one of the first and second gas flow rate control units based on a detection signal from the liquid level detector.

【0018】

Further, the bump forming apparatus according to claim 7 of the present invention is the bump forming apparatus according to claim 6, and the liquid level height of the molten solder in the first tank is higher than a preset height. It is further provided with a solder breakage display unit that displays the solder breakage when the value becomes low.

【0019】

The bump forming apparatus according to claim 8 of the present invention is the bump forming apparatus according to claim 6, and drives a removable nozzle lid that closes the first opening and a nozzle lid. It further includes a drive unit.

【0020】

Further, the bump forming apparatus according to claim 9 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and is provided in a pipe to remove impurities contained in molten solder. It is further provided with a filter for removing.

【0021】

The bump forming apparatus according to claim 10 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and is provided around the first opening and has a bottom surface. It further includes an open cover and an inert gas introduction port for introducing the inert gas into the cover.

【0022】

Further, the bump forming apparatus according to claim 11 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and the presence or absence of dropping of molten solder from the first opening. It is further provided with a sensor for detecting.

【0023】

Further, the bump forming apparatus according to claim 12 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and is located between the first opening and the bump forming target. A cover with open top and bottom surfaces, a reduction gas introduction port for introducing reduction gas into the cover, and heating for locally heating the bumps, which are arranged near the bump formation location in the molten solder dropping path of It is further equipped with an instrument.

【0024】

The bump forming apparatus according to claim 13 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and is a removable nozzle cap that closes the first opening. Further, an inert gas introduction pipe for introducing an inert gas into the nozzle cap and a drive unit for driving the nozzle cap are further provided.

【0025】

Further, the bump forming apparatus according to claim 14 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and the first heater heats the first tank. It has a third heater and a fourth heater that heats the cavity separately.

【0026】

The bump forming device according to claim 15 of the present invention is the bump forming device according to any one of claims 1 to 8, and is removable from the first opening, and the first A suction device for sucking molten solder from the opening of the screw device and a drive unit for driving the suction device are further provided.

【0027】

The bump forming apparatus according to claim 16 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and adheres to the bottom surface of the nozzle around the first opening. It is further provided with a solder residue removing device for wiping and removing the solder residue, and a drive unit for driving the solder residue removing device.

【0028】

The bump forming apparatus according to claim 17 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and the bottom surface of the nozzle around the first opening is soldered. It is characterized by being coated with a material that repels.

【0029】

The bump forming apparatus according to claim 18 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and at least the inner surface of the first tank and the cavity is made of solder. It is characterized by being coated with a familiar material.

【0030】

Further, the bump forming apparatus according to claim 19 of the present invention is the bump forming apparatus according to any one of claims 1 to 8, and further has a lattice structure provided in the first tank. To prepare.

【0031】

The bump forming apparatus according to claim 20 of the present invention comprises a cavity for accumulating molten solder, a nozzle arranged in the lower part of the cavity and having a first opening on the bottom surface, and a first opening. A pressurizing element for appropriately pressurizing the molten solder in the cavity toward the first opening is provided for dropping the molten solder, and the pressurizing element is provided on a diaphragm arranged at the upper part of the cavity and on the upper surface of the diaphragm. It has a fixed piezoelectric element, and the diaphragm is characterized in that the molten solder in the cavity can be pressurized in the direction of the first opening and in the direction opposite to the direction of the first opening. It is a thing.

【0032】

Further, the semiconductor manufacturing apparatus according to claim 21 of the present invention includes the bump forming apparatus according to any one of claims 1 to 20.

【0033】

The bump forming method according to claim 22 of the present invention includes (a) a step of putting solid solder into the container, (b) a step of putting the inside of the container in a vacuum state, and (c) a container. The step of melting the solid solder into molten solder by heating, and (d) the step of releasing the vacuum state in the container after removing the bubbles mixed in the molten solder, and (e) It is provided with a step of discharging molten solder to a bump forming target.

【0034】

Further, in the bump forming method according to claim 23 of the present invention, the molten solder accumulated in the cavity is pressed by a pressurizing element arranged in the upper part of the cavity, so that the nozzle is arranged in the lower part of the cavity. This is a bump forming method in which molten solder is discharged onto a bump forming target from the above. It includes a step of pressurizing in a direction opposite to the nozzle direction by a pressurizing element.

【0035】

Further, the bump forming method according to claim 24 of the present invention is a bump forming method for forming a bump on a bump forming target by discharging the accumulated molten solder from a nozzle, and the nozzle (a) It is provided with a step of discharging the molten solder from the surface as a dummy, and a step of discharging the molten solder to the bump forming target after the step (b) and the step (a).

【0036】

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1. FIG. 1 is a cross-sectional view schematically showing a configuration of a bump forming apparatus according to a first embodiment of the present invention. The bump forming apparatus shown in FIG. 1 stores a molten solder 1 in which solder as a bump material is melted, and has a first tank 3 having an outlet 2 of the molten solder 1 on the bottom surface and one end connected to the outlet 2. A cavity 6 having a pipe 4 having a pipe 4 and a cavity 6 having an inflow port 5 of molten solder 1 connected to the other end of the pipe 4 and arranged below the first tank 3, and a cavity 6 placed below the cavity 6 and on the bottom surface. It is composed of a nozzle 8 having a first opening 7, a diaphragm 9 arranged above the cavity 6, and a piezoelectric element 10 fixed to the upper surface of the diaphragm 9, and molten solder in the cavity 6 is applied by applying a voltage from the outside. By appropriately pressurizing 1 in the direction of the first opening 7, the pressurizing element for dropping the molten solder 1 from the first opening 7 and the first tank 3, the pipe 4, and the cavity 6 are heated. It is equipped with a first heater 11.

【0037】

Further, the bump forming apparatus shown in FIG. 1 has a second tank 14 arranged above the first tank 3, which stores the solid solder 12 and has a second opening 13 on the bottom surface. A second heater 15 provided around the second opening 13 for heating and melting the solder 12 near the second opening 13 and dropping it into the first tank 3 as molten solder, and a second heater. Drive (temperature rise / fall) of the liquid level detector 16 that detects the liquid level height of the molten solder 1 in the tank 3 of 1 and the second heater 15 based on the detection signal from the liquid level detector 16. It is provided with a static pressure control unit having a liquid level control unit 17 for controlling.

【0038】

Further, the bump forming apparatus shown in FIG. 1 is for exhausting the inert gas from the inert gas introduction pipe 18 for introducing the inert gas such as nitrogen into the second tank 14 and the second tank 14. It is equipped with an inert gas exhaust pipe 19.

【0039】

Further, the bump forming apparatus shown in FIG. 1 has an inert gas introduction pipe 20 for introducing an inert gas into the first tank 3 and an inert gas for exhausting the inert gas from the first tank 3. It is equipped with a gas exhaust pipe 21.

【0040】

Further, the bump forming apparatus shown in FIG. 1 is provided in the pipe 4 and includes a mesh-shaped filter 22 made of ceramic or SuS for removing impurities such as Fe contained in the molten solder 1.

【0041】

Further, the bump forming apparatus shown in FIG. 1 is provided around the first opening 7, and has an atmosphere cover 23 having an open bottom surface and an inert gas introduction pipe for introducing the inert gas into the atmosphere cover 23. It has 24 and.

【0042】

Further, the bump forming apparatus shown in FIG. 1 includes a sensor 25 for detecting the presence or absence of dripping of molten solder 1 from the first opening 7. Since the discharge speed of the molten solder 1 from the first opening 7 is as high as 1 m / s to 5 m / s, a hold circuit (not shown) for holding the output signal from the sensor 25 for a certain period of time is provided to hold the molten solder 1. It is desirable to detect the presence or absence of dripping of molten solder 1 from the first opening 7 by the hold signal output from the circuit.

【0043】

Further, the bump forming apparatus shown in FIG. 1 was arranged in the vicinity of the bump 29 forming portion in the dropping path of the molten solder 1 between the first opening 7 and the chip 26 on which the bump 29 is formed. A reduction atmosphere cover 27 having an open top and bottom surface, a reduction gas introduction pipe 28 for introducing the reduction gas into the reduction atmosphere cover 27, and a heating torch 30 for heating the bump 29 are provided. Here, the chip 26 is placed on a heat stage 31 for heating the chip 26 to a constant temperature below the solder melting point.

【0044】

Hereinafter, a bump forming method using the bump forming apparatus shown in FIG. 1 will be described. First, the solid solder 12 is put into the second tank 14. Next, the solder 12 near the second opening 13 is heated and melted by the second heater 15 and dropped into the first tank 3 as the molten solder 1. Here, the molten solder 1 is dropped from the second tank 14 until the liquid level height of the molten solder 1 accumulated in the first tank 3 reaches a predetermined position. Specifically, this is performed until the liquid level detector 16 detects contact with the molten solder 1.

【0045】

The molten solder 1 accumulated in the first tank 3 flows into the cavity 6 from the outflow port 2 through the pipe 4, the filter 22, and the inflow port 5 by its own weight, and fills the inside of the cavity 6. At this time, the temperature of the first tank 3, the pipe 4, and the cavity 6 is raised by the first heater 11. In addition, the inert gas is introduced into the first tank 3 from the inert gas introduction pipe 20 in advance, the inert gas is exhausted from the inert gas exhaust pipe 21, and the inert gas introduction pipe 18 to the second tank 18 to the second tank. Inert gas is introduced into 14 and the inert gas is exhausted from the inert gas exhaust pipe 19. In addition, the inert gas is introduced into the atmosphere cover 23 from the inert gas introduction pipe 24.

【0046】

Next, by applying a voltage to the piezoelectric element 10 from the outside to extend the piezoelectric element 10, the diaphragm 9 is displaced in the direction of the first opening 7, and the molten solder 1 is displaced by this pressure in the first opening. Drop from 7. When the molten solder 1 is dropped from the first opening 7, the liquid level height of the molten solder 1 in the first tank 3 decreases, and the molten solder 1 and the liquid level detector 16 do not come into contact with each other. .. Then, the liquid level control unit 17 detects this and drives the second heater 15 to replenish the molten solder 1 in the first tank 3. As a result, the liquid level height of the molten solder 1 in the first tank 3 is maintained at a constant height.

【0047】

The molten solder 1 dropped from the first opening 7 passes through the atmosphere cover 23 and the reducing atmosphere cover 27 in this order, reaches a predetermined bump forming portion (for example, an electrode, etc.) on the chip 26, and bumps. It becomes 29 and sticks on the chip 26.

【0048】

The fixed bumps 29 are locally heated for each bump by the heating torch 30 in the reducing atmosphere cover 27. Local heating by the heating torch 30 can be performed by irradiating the bump 29 with a laser, discharging the bump 29, or the like. At this time, the reducing gas (for example, H) is contained in the reducing atmosphere cover 27 from the reducing gas introduction pipe 28.₂5% + N₂95%) has been introduced. As a result, the surface oxidation of the bump 29 is reduced.

【0049】

FIG. 2 is a cross-sectional view showing a state of the molten solder 1 in the vicinity of the first opening 7. The static pressure of the molten solder 1 applied to the nozzle 8 is proportional to the height from the nozzle 8 to the liquid level of the molten solder 1 in the first tank 3. As described above, according to the bump forming apparatus and the bump forming method according to the first embodiment, the liquid level height of the molten solder 1 in the first tank 3 can be maintained at a constant height, so that the molten solder 1 is added to the nozzle 8. The static pressure of the molten solder 1 can be kept constant. Therefore, even when the viscosity of the solder material is high, the sagging dimension A1 of the molten solder 1 from the nozzle 8 can be set to a constant value in a short time and a constant time as shown in FIG. Therefore, it is possible to stabilize the discharge of the molten solder 1 from the first opening 7.

【0050】

Further, since the inert gas is introduced from the inert gas introduction pipe 18 into the second tank 14, it is possible to prevent the solid solder 12 from being oxidized in the second tank 14.

【0051】

Further, since the inert gas is introduced from the inert gas introduction pipe 20 into the first tank 3, it is possible to prevent the molten solder 1 from being oxidized in the first tank 3.

【0052】

Further, since the impurities contained in the molten solder 1 can be removed by the filter 22, it is possible to prevent the nozzle 8 from being clogged due to the oxidation of these impurities.

【0053】

Further, since the atmosphere cover 23 is provided around the first opening 7 and the inert gas is introduced into the atmosphere cover 23 from the inert gas introduction pipe 24, the molten solder 1 accumulated in the cavity 6 and the nozzle 8 is used. Can be prevented from being oxidized from the first opening 7.

【0054】

Further, since the discharge sensor 25 detects the presence or absence of the molten solder 1 dripping from the first opening 7, it is preliminarily made that a defective chip is produced by stopping the operation of the device in the case of a discharge failure. Can be prevented.

【0055】

Further, since the surface oxidation of the bump 29 fixed on the chip 26 can be reduced by the reducing atmosphere cover 27 and the heating torch 30, the bonding between the chip 26 and the bump 29 can be improved. By the way, in general, in order to reduce a solder bump, it is necessary to heat the solder bump to 300 ° C. or higher. Therefore, if the heat-resistant temperature of the chip or substrate to be bumped is low, a problem may occur in the chip or the like when the chip or the like is heated as a whole. However, according to the bump forming apparatus and the bump forming method according to the first embodiment, only the bump 29 is locally heated by the heating torch 30 instead of heating the chip 26 as a whole, so that the entire chip 26 is heated. Compared with the case of heating, it is possible to suppress the occurrence of defects in the chip 26.

【0056】

Moreover, since the conventional bump forming apparatus uses a flux for the paste, a step and an apparatus for cleaning the flux after forming the bumps are required. On the other hand, according to the bump forming apparatus and the bump forming method according to the first embodiment, since the flux is not used, the flux cleaning step and the cleaning apparatus become unnecessary, and the processing step and the processing apparatus can be simplified. ..

【0057】

Embodiment 2. FIG. 3 is a cross-sectional view schematically showing a configuration of a bump forming apparatus according to a second embodiment of the present invention. However, the description of the tip 26, the reducing atmosphere cover 27, the reducing gas introduction pipe 28, and the heat stage 31 shown in FIG. 1 is omitted. The bump forming apparatus according to the second embodiment is based on the bump forming apparatus according to the first embodiment shown in FIG. 1, a second tank 14, a second heater 15, a liquid level detector 16, and a liquid level detector 16. Instead of the static pressure control unit according to the first embodiment having the liquid level control unit 17, another static pressure control unit is provided.

【0058】

As shown in FIG. 3, the static pressure control unit according to the second embodiment includes the inert gas introduction pipe 36 for introducing the inert gas into the first tank 3, and the inert gas introduction pipes 36 to the third. A first valve 37 for controlling the amount of inert gas flowing into the tank 3 of 1, an inert gas exhaust pipe 38 for exhausting the inert gas from the first tank 3, and a first tank. A second valve 39 for controlling the amount of inert gas flowing out from 3 through the inert gas exhaust pipe 38, and a liquid for detecting the liquid level height of the molten solder 1 in the first tank 3. The first is based on the surface height sensor 40, the gas pressure sensor 43 that detects the gas pressure of the inert gas in the first tank 3, and the detection signals from the liquid level height sensor 40 and the gas pressure sensor 43. It has a gas pressure control unit 44 that controls the drive of at least one of the valve 37 and the second valve 39.

【0059】

The liquid level height sensor 40 is fixed to the upper surface of the first tank 3 by the sensor mounting plate 41. Further, a well-known optical sensor can be used as the liquid level height sensor 40, and the light emitted by the liquid level height sensor 40 is emitted from the upper surface of the first tank 3 in the lower portion of the liquid level height sensor 40. A glass window 42 for passing through is provided.

【0060】

Hereinafter, a bump forming method using the bump forming apparatus shown in FIG. 3 will be described. First, the solid solder is put into the first tank 3, and then the solid solder is heated and melted by the first heater 11 to accumulate the molten solder 1 in the first tank 3. The molten solder 1 accumulated in the first tank 3 fills the cavity 6 in the same manner as described above. The liquid level sensor 40 detects the liquid level h1 of the molten solder 1 in the first tank 3 at this time, and inputs this to the gas pressure control unit 44. The gas pressure control unit 44 stores the liquid level height h1 input from the liquid level height sensor 40.

【0061】

Next, the inert gas is introduced from the inert gas introduction pipe 36 into the first tank 3. At this time, the amount of the inert gas flowing from the inert gas introduction pipe 36 into the first tank 3 is controlled to a constant amount by the first valve 37. Further, the inert gas introduced into the first tank 3 is exhausted to the outside through the inert gas exhaust pipe 38. The gas pressure sensor 43 detects the gas pressure Pb1 of the inert gas in the first tank 3 at this time, and inputs this to the gas pressure control unit 44. The gas pressure control unit 44 stores the gas pressure Pb1 input from the gas pressure sensor 43.

【0062】

Next, the molten solder 1 is dropped from the first opening 7 by displacing the diaphragm 9 by the piezoelectric element 10 in the same manner as in the first embodiment. As described above, when the molten solder 1 is dropped from the first opening 7, the liquid level height of the molten solder 1 in the first tank 3 decreases.

【0063】

By the way, the relationship of P = h × ρ × G + Pb is established between the static pressure P of the molten solder 1 applied to the nozzle 8 and the gas pressure Pb of the inert gas in the first tank 3. Here, h is the height from the nozzle 8 to the liquid level of the molten solder 1 in the first tank 3, ρ is the density of the molten solder 1, and G is gravity. Since ρ and G are known in this equation, P can be kept constant by adjusting Pb when h changes.

【0064】

As described above, the liquid level height of the molten solder 1 in the first tank 3 is lowered by the dropping of the molten solder 1 from the first opening 7, but the liquid level height sensor 40 is the first tank. The liquid level h2 of the molten solder 1 in 3 is sequentially detected, and this is input to the gas pressure control unit 44. The gas pressure control unit 44 calculates the amount of change Δh in the liquid level height of the molten solder 1 based on the input liquid level height h2 and the liquid level height h1 stored in advance. Further, the gas pressure control unit 44 calculates the gas pressure Pb2 of the inert gas for keeping the static pressure P of the molten solder 1 applied to the nozzle 8 at a constant value with reference to the amount of change Δh in the liquid level. , Calculate the difference value ΔPb from the gas pressure Pb1 stored in advance. Then, the gas pressure control unit 44 adjusts the second valve 39 so as to replenish the difference value ΔPb, that is, so that the gas pressure of the inert gas in the first tank 3 becomes Pb2.

【0065】

In the above description, the amount of the inert gas introduced from the inert gas introduction pipe 36 into the first tank 3 is kept constant, and the first one is adjusted according to the decrease in the liquid level of the molten solder 1. The case where the amount of the inert gas exhausted from the tank 3 to the outside through the inert gas exhaust pipe 38 is gradually reduced has been described. However, on the contrary, the amount of the inert gas exhausted from the first tank 3 to the outside is kept constant, and the inside of the first tank 3 is changed according to the decrease in the liquid level of the molten solder 1. The amount of the introduced inert gas may be gradually increased.

【0066】

Further, when the amount of the molten solder 1 accumulated in the first tank 3 is small from the beginning, the amount of change in the static pressure of the molten solder 1 due to the decrease in the liquid level is also small, as described above. No static pressure control of the molten solder 1 is required.

【0067】

As described above, according to the bump forming apparatus and the bump forming method according to the second embodiment, the molten solder 1 does not enter the first tank 3 in accordance with the decrease in the liquid level of the molten solder 1. Since the gas pressure of the active gas is gradually increased, the static pressure of the molten solder 1 applied to the nozzle 8 can be maintained at a constant value. Therefore, similarly to the bump forming apparatus and the bump forming method according to the first embodiment, it is possible to stabilize the discharge of the molten solder 1 from the first opening 7.

【0068】

Embodiment 3. FIG. 4 is a cross-sectional view schematically showing the configuration of the bump forming apparatus according to the third embodiment of the present invention. As shown in FIG. 4, the bump forming apparatus according to the third embodiment is an error display unit connected to the gas pressure control unit 44 based on the bump forming apparatus according to the second embodiment shown in FIG. It is equipped with 45 more.

【0069】

As a result of detecting the liquid level of the molten solder 1 by the liquid level sensor 40, it is determined that the liquid level of the molten solder 1 in the first tank 3 is lower than a preset predetermined value. When the unit 44 determines, the gas pressure control unit 44 displays an arbitrary display indicating the solder shortage on the error display unit 45.

【0070】

As described above, according to the bump forming apparatus according to the third embodiment, when the liquid level height of the molten solder 1 becomes lower than the preset predetermined value, the error display unit 45 displays the solder breakage. , It is possible to make the operator recognize the solder breakage in the first tank 3 at an early stage.

【0071】

Embodiment 4. In the bump forming apparatus and the bump forming method according to the second embodiment, after the solid solder is put into the first tank 3, the solid solder is heated by the first heater 11. -By melting, molten solder 1 was accumulated in the first tank 3. At this time, if air bubbles are contained in the solid solder, the air bubbles are mixed in the molten solder 1 when the solder is melted, and the discharge amount and the discharge position of the molten solder 1 from the first opening 7 May cause variations in. In addition, air bubbles remaining on the contact surface between the cavity 6 and the diaphragm 9 may cause the above variation. The fourth embodiment proposes a bump forming apparatus and a bump forming method capable of realizing stability of the discharge amount and the discharge position of the molten solder 1 by removing such bubbles in advance.

【0072】

FIG. 5 is a cross-sectional view schematically showing the configuration of the bump forming apparatus according to the fourth embodiment of the present invention. As shown in FIG. 5, the bump forming apparatus according to the fourth embodiment is based on the bump forming apparatus according to the second embodiment shown in FIG. 3, and closes and detaches the first opening 7 from below. It is further provided with a flexible nozzle lid 34 and a nozzle lid driving unit 35 for driving the nozzle lid 34. Other configurations of the bump forming apparatus according to the fourth embodiment are the same as the configurations of the bump forming apparatus according to the second embodiment shown in FIG.

【0073】

Hereinafter, a bump forming method using the bump forming apparatus shown in FIG. 5 will be described. First, the solid solder is put into the first tank 3. Further, the nozzle lid 34 is driven by the nozzle lid driving unit 35, and the first opening 7 is closed by the nozzle lid 34 from below.

【0074】

Next, by closing the first valve 37 and opening the second valve 39, the air in the first tank 3 is exhausted to the outside through the inert gas exhaust pipe 38, and the first valve is opened. The inside of the tank 3, the pipe 4, and the cavity 6 of 1 is evacuated. In this state, the solid solder is heated and melted by the first heater 11 to accumulate the molten solder 1 in the first tank 3.

【0075】

After the air bubbles mixed in the molten solder 1 are sufficiently removed (about 15 minutes later), the first valve 37 is opened, and the inert gas is introduced from the inert gas introduction pipe 36 into the first tank 3. By introducing the above, the inside of the first tank 3 is returned to the atmospheric pressure. Next, the nozzle lid 34 is driven by the nozzle lid driving unit 35, and the nozzle lid 34 is removed from the first opening 7. After that, the operation of detecting the liquid level h1 of the molten solder 1 by the liquid level sensor 40 described in the second embodiment is continued.

【0076】

As described above, according to the bump forming apparatus and the bump forming method according to the fourth embodiment, the bubbles mixed in the molten solder 1 can be removed in advance, and thus the first opening 7 is caused by these bubbles. It is possible to prevent variations in the discharge amount and discharge position of the molten solder 1 from the above.

【0077】

Embodiment 5. FIG. 6 is a cross-sectional view showing a partially enlarged configuration of a bump forming apparatus according to a fifth embodiment of the present invention. As shown in FIG. 6, the bump forming apparatus according to the fifth embodiment has a removable nozzle cap 46 that closes the first opening 7, and a non-removable nozzle cap 46 for introducing an inert gas into the nozzle cap 46. It includes an active gas introduction pipe 47 and a nozzle cap drive unit 48 for driving the nozzle cap 46.

【0078】

For example, when the device is stopped, such as when the chip 26 is waiting for transportation, the nozzle cap 46 is driven by the nozzle cap driving unit 48, so that the first opening 7 is closed from below by the nozzle cap 46. Then, the inert gas is introduced from the inert gas introduction pipe 47 into the nozzle cap 46.

【0079】

As described above, according to the bump forming apparatus and the bump forming method according to the fifth embodiment, it is possible to prevent the molten solder 1 in the cavity 6 from being oxidized from the first opening 7 while the apparatus is stopped. it can.

【0080】

Embodiment 6. FIG. 7 is a cross-sectional view schematically showing the configuration of the bump forming apparatus according to the sixth embodiment of the present invention. As shown in FIG. 7, in the bump forming apparatus according to the sixth embodiment, the first heater 11 is for heating the third heater 11a for heating the first tank 3 and the cavity 6. It has a fourth heater 11b separately.

【0081】

Then, the third heater 11a raises the temperature of the molten solder 1 in the first tank 3 to about the solder melting temperature, and the fourth heater 11b raises the molten solder 1 in the cavity 6 to a temperature higher than the solder melting temperature. Raise to a high temperature.

【0082】

As described above, according to the bump forming apparatus and the bump forming method according to the sixth embodiment, the temperature of the molten solder 1 in the cavity 6 is raised to a high temperature. As a result, the viscosity of the molten solder 1 near the nozzle 8 is lowered, so that even if the viscosity of the molten solder 1 is high, a stable discharge amount of the molten solder 1 from the first opening 7 can be ensured. Can be done. Moreover, since the molten solder 1 in the first tank 3 rises to about the solder melting temperature, it does not promote the progress of oxidation of the molten solder 1 in the first tank 3.

【0083】

Embodiment 7. FIG. 8 is a cross-sectional view showing a partially enlarged configuration of a bump forming apparatus according to a seventh embodiment of the present invention. As shown in FIG. 8, the bump forming apparatus according to the seventh embodiment is detachable from the first opening 7 and has a suction pad 49 for sucking the molten solder 1 from the first opening 7. It is provided with a discharge pipe 50 for discharging the sucked molten solder 1 to the outside of the apparatus, and a suction pad drive unit 51 for driving the suction pad 49.

【0084】

As shown in FIG. 8, when air bubbles 52 are mixed in the molten solder 1 in the nozzle 8 and the ejection of the molten solder 1 from the first opening 7 becomes unstable, or the device is stopped for a long time. When the molten solder 1 in the nozzle 8 is oxidized from the first opening 7, the suction pad 49 is driven by the suction pad driving unit 51 to press the suction pad 49 against the first opening 7. Then, the molten solder 1 in the nozzle 8 is sucked, and the sucked molten solder 1 is discharged to the outside of the apparatus by the discharge pipe 50.

【0085】

As described above, according to the bump forming apparatus and the bump forming method according to the seventh embodiment, the molten solder 1 in which the bubbles 52 are mixed or oxidized from the first opening 7 can be suction-removed by the suction pad 49. it can. Therefore, the stability of discharge of the molten solder 1 from the first opening 7 can be ensured.

【0086】

8. FIG. 9 is a partially enlarged cross-sectional view showing the configuration of the bump forming apparatus according to the eighth embodiment of the present invention. As shown in FIG. 9, the bump forming apparatus according to the eighth embodiment is detachable from the first opening 7, and removes the solder residue for removing the solder residue 53 around the first opening 7. It includes an instrument 54 and a drive unit 55 for driving the solder residue removing instrument 54. As the solder residue removing device 54, for example, heat-resistant rubber or the like can be used.

【0087】

As shown in FIG. 9, when the molten solder 1 is discharged from the first opening 7 with the solder residue 53 attached to the surface of the nozzle 8, the discharge direction of the molten solder 1 is indicated by an arrow due to the influence of the solder residue 53. It can be bent in the I direction. As a result, the accuracy of the discharge position of the molten solder 1 on the chip 26 becomes low.

【0088】

Therefore, the solder residue removing device 54 is driven in the direction of arrow G by the drive unit 55 to press the solder residue removing device 54 against the nozzle 8, and then the solder residue removing device 54 is driven in the direction of arrow H in this state. , Wipe off the solder residue 53.

【0089】

The operation of removing the solder residue 53 by the solder residue removing device 54 is executed when the accuracy of the discharge position of the molten solder 1 is lowered or when the operation is restarted after the device is stopped. Alternatively, it may be executed periodically during continuous operation of the device.

【0090】

As described above, according to the bump forming apparatus and the bump forming method according to the eighth embodiment, the solder residue 53 adhering to the surface of the nozzle 8 can be removed, so that the ejection position of the molten solder 1 can be stabilized. it can.

【0091】

Embodiment 9. FIG. 10 is a cross-sectional view showing a partially enlarged configuration of a bump forming apparatus according to a ninth embodiment of the present invention. As shown in FIG. 10, in the bump forming apparatus according to the ninth embodiment, the surface of the nozzle 8 is coated with the coating material 56. As the material of the coating material 56, a material that repels solder, for example, a material such as polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), parafluoroalkoxy fluororesin (PFA), ceramic, or titanium is used.

【0092】

As described above, according to the bump forming apparatus according to the ninth embodiment, the surface of the nozzle 8 is coated with a material that repels solder. Therefore, since the solder residue does not easily adhere to the surface of the nozzle 8, the discharge position of the molten solder 1 can be stabilized.

【0093】

Embodiment 10. In the bump forming apparatus according to each of the above embodiments, the surface with which the molten solder 1 comes into contact, for example, the inner surface of the first tank 3, the inner surface of the pipe 4, the inner surface of the cavity 6, and the like are adapted to the solder. Coat with material. The coating is performed by plating or vapor-depositing a material such as solder, nickel, or gold.

【0094】

As described above, according to the bump forming apparatus according to the tenth embodiment, by coating the surface in contact with the molten solder 1 with a material that is compatible with the solder, bubbles are less likely to be generated in the molten solder 1, so that the ejection can be performed. Stabilization can be achieved.

【0095】

Embodiment 11. FIGS. 11 and 12 are a perspective view and a top view showing a configuration of a first tank 3 in the bump forming apparatus according to the eleventh embodiment of the present invention. As shown in FIGS. 11 and 12, a lattice structure 57 was provided in the first tank 3.

【0096】

A plurality of electrodes to be bumped are actually formed on the chip 26, and in order to form bumps 29 on all the electrodes, it is necessary to move the bump forming apparatus in order by an XY table or the like (not shown). .. At this time, when the molten solder 1 swings up and down in the first tank 3, the static pressure of the molten solder 1 applied to the nozzle 8 changes, and as a result, the molten solder 1 is also discharged from the first opening 7. It becomes unstable.

【0097】

However, according to the bump forming apparatus according to the eleventh embodiment, since the lattice structure 57 is provided in the first tank 3, it is possible to suppress the shaking of the molten solder 1 in the first tank 3 and discharge the molten solder 1. Can be stabilized.

【0098】

Embodiment 12. In the present embodiment 12, bump formation capable of stably securing the discharge amount of the molten solder 1 discharged from the first opening 7 even when the viscosity of the molten solder 1 is high. Suggest a method.

【0099】

13 and 14 are schematic views for explaining the bump forming method according to the twelfth embodiment of the present invention. The state in which no voltage is applied to the piezoelectric element 10 from the outside is shown in FIG. From this state, for example, a positive voltage is applied to the piezoelectric element 10 to extend the piezoelectric element 10 and push down the diaphragm 9 in the direction of arrow X. As a result, pressure is applied from the diaphragm 9 to the molten solder 1, and the molten solder 1 is on the verge of being dropped from the first opening 7 (FIG. 13).

【0100】

Next, the piezoelectric element 10 is contracted by applying, for example, a negative voltage to the piezoelectric element 10 from the outside, and the diaphragm 9 is pulled up in the direction of the arrow Y. As a result, the molten solder 1 is cut well in the vicinity of the first opening 7, and the molten solder 1 is dropped from the first opening 7.

【0101】

As described above, according to the bump forming method according to the twelfth embodiment, the diaphragm 9 is once pushed down in the direction of arrow X and then pulled up in the direction of arrow Y. As a result, even when the viscosity of the molten solder 1 is high, the molten solder 1 is cut well in the vicinity of the first opening 7, and the discharge amount of the molten solder 1 discharged from the first opening 7 is improved. Can be stably secured.

【0102】

Embodiment 13. When the stop time of the apparatus is long, the degree of oxidation of the molten solder 1 from the first opening 7 becomes remarkable, and the discharge of the first molten solder 1 after the operation of the apparatus is restarted becomes unstable. May become. Therefore, after the operation of the device is restarted, the dummy discharge is performed once (or a plurality of times as necessary), and then the discharge to the chip 26 is started. Further, not only after the operation of the apparatus is restarted, but also when it is determined that the degree of oxidation of the molten solder 1 from the first opening 7 is remarkable, the same dummy discharge may be performed.

【0103】

As described above, according to the bump forming method according to the thirteenth embodiment, it is possible to stabilize the discharge to the chip 26 by performing dummy discharge after restarting the operation of the apparatus or the like.

【0104】

[Effect of the invention]

According to the first aspect of the present invention, since the static pressure of the molten solder applied to the nozzle is maintained at a constant value, the ejection of the molten solder from the first opening can be stabilized.

【0105】

Further, according to claim 2 of the present invention, the molten solder discharged from the first opening is cut well, so that even when the viscosity of the molten solder is high, the first opening It is possible to stably secure the discharge amount of the molten solder discharged from the portion.

【0106】

Further, according to claim 3 of the present invention, the static pressure of the molten solder applied to the nozzle is kept constant by keeping the liquid level height of the molten solder in the first tank constant. Can be done.

【0107】

Further, according to claim 4 of the present invention, it is possible to prevent the solid solder from being oxidized in the second tank.

【0108】

Further, according to claim 5 of the present invention, it is possible to prevent the molten solder from being oxidized in the first tank.

【0109】

Further, according to claim 6 of the present invention, the gas pressure of the inert gas in the first tank is gradually increased in accordance with the decrease in the liquid level of the molten solder in the first tank. By doing so, the static pressure of the molten solder applied to the nozzle can be maintained at a constant value.

【0110】

Further, according to claim 7 of the present invention, the operator can be made to recognize the solder breakage at an early stage.

【0111】

Further, according to claim 8 of the present invention, a step of pouring solid solder into the first tank and a first gas flow rate control unit by closing the first opening with a nozzle lid. Is "closed" and the second gas flow rate control unit is "opened" to create a vacuum inside the first tank and cavity, and the first heater heats and melts the solid solder. After removing the air bubbles mixed in the molten solder, the nozzle lid is removed and the first gas flow rate control unit is opened. Can be removed. Therefore, it is possible to stabilize the discharge amount and the discharge position of the molten solder from the first opening.

【0112】

Further, according to claim 9 of the present invention, impurities contained in the molten solder can be removed by a filter, and the nozzles can be prevented from being clogged due to oxidation of the impurities.

【0113】

Further, according to claim 10 of the present invention, it is possible to prevent the molten solder accumulated in the nozzle from being oxidized from the first opening.

【0114】

Further, according to the eleventh aspect of the present invention, it is possible to prevent the defective chip from being produced in advance by stopping the operation of the device in the case of a discharge failure.

【0115】

Further, according to claim 12 of the present invention, since the surface oxidation of the bump can be reduced, the bonding between the bump formation target and the bump can be improved. Moreover, since the heating device does not heat the bump forming target as a whole, but only locally heats the bump forming target, a defect of the bump forming target occurs as compared with the case where the bump forming target is heated as a whole. It can be suppressed.

【0116】

Further, according to the thirteenth aspect of the present invention, the first opening is closed with the nozzle cap while the apparatus is stopped, and the inert gas is introduced into the nozzle cap to melt the inside of the nozzle. It is possible to prevent the solder from being oxidized from the first opening.

【0117】

Further, according to claim 14, the viscosity of the molten solder in the vicinity of the nozzle can be reduced by heating the cavity to a temperature higher than the solder melting temperature by the fourth heater, even if the viscosity of the molten solder in the vicinity of the nozzle is lowered. Even when the viscosity of the molten solder is high, a stable discharge amount of the molten solder from the first opening can be ensured. Moreover, by heating the first tank to about the solder melting temperature by the third heater, the progress of oxidation of the molten solder in the first tank is not promoted.

【0118】

Further, according to claim 15, of the present invention, molten solder mixed with air bubbles or oxidized from the first opening can be suction-removed by a suction device. Therefore, it is possible to stabilize the discharge of the molten solder from the first opening.

【0119】

Further, according to claim 16 of the present invention, the discharge position of the molten solder can be stabilized by wiping and removing the solder residue adhering to the bottom surface of the nozzle with a solder residue removing device.

【0120】

Further, according to claim 17 of the present invention, since the solder residue is unlikely to adhere to the bottom surface of the nozzle, the discharge position of the molten solder can be stabilized.

【0121】

Further, according to claim 18 of the present invention, since bubbles are less likely to be generated in the molten solder, it is possible to stabilize the discharge.

【0122】

Further, according to claim 19 of the present invention, the lattice structure provided in the first tank can suppress the shaking of the molten solder in the first tank. Therefore, the static pressure of the molten solder applied to the nozzle can be stabilized, and the discharge can be stabilized.

【0123】

Further, according to claim 20, of the present invention, the molten solder discharged from the first opening is cut well, so that even when the viscosity of the molten solder is high, the first opening It is possible to stably secure the discharge amount of the molten solder discharged from the portion.

【0124】

Further, according to claim 21 of the present invention, it is possible to manufacture a semiconductor device having no bump formation defect.

【0125】

Further, according to claim 22 of the present invention, since bubbles mixed in the molten solder can be removed when the solid solder is heated and melted, the molten solder is caused by these bubbles. It is possible to prevent variations in the discharge amount and the discharge position of the above.

【0126】

Further, according to claim 23 of the present invention, the molten solder discharged from the first opening is cut well, so that the molten solder is discharged even when the viscosity of the molten solder is high. The amount can be stably secured.

【0127】

Further, according to claim 24 of the present invention, even when the accumulated molten solder is oxidized from the nozzle due to a long-term device stop or the like, it is targeted for bump formation after performing dummy discharge. On the other hand, since the molten solder is discharged, it is possible to stabilize the discharge to the bump forming target.

[Simple explanation of drawings]

[Figure 1]

It is sectional drawing which shows typically the structure of the bump forming apparatus which concerns on Embodiment 1 of this invention.

[Figure 2]

It is sectional drawing which shows the state of molten solder in the vicinity of the 1st opening.

[Fig. 3]

It is sectional drawing which shows typically the structure of the bump forming apparatus which concerns on Embodiment 2 of this invention.

[Fig. 4]

It is sectional drawing which shows typically the structure of the bump forming apparatus which concerns on Embodiment 3 of this invention.

[Fig. 5]

It is sectional drawing which shows typically the structure of the bump forming apparatus which concerns on Embodiment 4 of this invention.

[Fig. 6]

It is sectional drawing which shows the structure of the bump forming apparatus which concerns on Embodiment 5 of this invention partially enlarged.

[Fig. 7]

It is sectional drawing which shows typically the structure of the bump forming apparatus which concerns on Embodiment 6 of this invention.

[Fig. 8]

It is sectional drawing which shows the structure of the bump forming apparatus which concerns on Embodiment 7 of this invention partially enlarged.

[Fig. 9]

It is sectional drawing which shows the structure of the bump forming apparatus which concerns on Embodiment 8 of this invention partially enlarged.

[Fig. 10]

It is sectional drawing which shows the structure of the bump forming apparatus which concerns on Embodiment 9 of this invention partially enlarged.

[Fig. 11]

It is a perspective view which shows the structure of the 1st tank in the bump forming apparatus which concerns on Embodiment 11 of this invention.

[Fig. 12]

It is a top view which shows the structure of the 1st tank in the bump forming apparatus which concerns on Embodiment 11 of this invention.

[Fig. 13]

It is a schematic diagram for demonstrating the bump formation method which concerns on Embodiment 12 of this invention.

[Fig. 14]

It is a schematic diagram for demonstrating the bump formation method which concerns on Embodiment 12 of this invention.

[Fig. 15]

It is sectional drawing which shows typically the structure of the conventional bump forming apparatus.

[Explanation of symbols]

1 molten solder, 2 outlet, 3 1st tank, 4 piping, 5 inlet, 6 cavity, 7 1st opening, 8 nozzles, 9 diaphragm, 10 piezoelectric element, 11 1st heater, 12 solder, 13 2nd opening, 14 2nd tank, 15 2nd heater, 16 liquid level detector, 17 liquid level control unit, 18,20,24,36,47 inert gas introduction pipe, 19,21, 38 Inactive gas exhaust pipe, 22 filter, 23 atmosphere cover, 25 discharge sensor, 26 chips, 27 reduction atmosphere cover, 28 reduction gas introduction pipe, 29 bumps, 30 heating torch, 40 liquid level height sensor, 43 gas pressure sensor , 44 Gas pressure control unit, 45 Error display unit, 34 Nozzle lid, 35 Nozzle lid drive unit, 46 Nozzle cap, 48 Nozzle cap drive unit, 11a 3rd heater, 11b 4th heater, 49 Suction pad, 50 Discharge Tube, 51 suction pad drive, 52 air bubbles, 53 solder residue, 54 solder residue remover, 55 drive, 56 coating material, 57 lattice structure.