Method for bonding circuit board and electronic parts

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a technique for joining an electronic component to a circuit board, and more particularly to a technique for joining an electronic component to a circuit board by liquid phase treatment. Electronic components include, for example, semiconductor integrated circuit devices, chip resistors, chip capacitors (capacitors), and the like.

【0002】

[Conventional technology]

As a method of joining electronic components to a circuit board, a surface mounting method using a solder paste is known. Solder paste is printed on the circuit board using a silk screen or a metal mask, electronic components are placed on the solder paste, and the electronic components are joined to the circuit board by melting and solidifying the solder paste.

【0003】

As semiconductor integrated circuit devices become more integrated, the dimensions of the junction terminals become smaller and the spacing between the terminals becomes narrower. When the terminal structure is miniaturized in this way, there is a limit to the solder paste supply method using a silk screen or a metal mask. Further, even if the solder paste can be supplied, the possibility that the solder balls generated at the time of soldering come into contact with each other and short-circuit between the terminals increases.

【0004】

A method of using a solder bump for joining a miniaturized semiconductor integrated circuit device or the like is known. A solder bump is formed on the junction terminal of the semiconductor integrated circuit device or the junction terminal of the circuit board, flux is applied at the time of bonding, the solder bump and the other terminal are brought into opposite contact with each other, and heated above the melting point of the solder bump. The solder bumps are melted and solidified to join the electronic components to the circuit board. According to this method, a fine joint structure can be obtained, but the number of man-hours is large and the cost tends to increase. It is difficult to reduce the cost because a process of making a solder bump, a process of placing the solder bump on a terminal of a semiconductor integrated circuit device, a process of mounting (joining), and the like are required.

【0005】

[Problems to be Solved by the Invention]

The conventional method of joining an electronic component to a circuit board has various restrictions. An object of the present invention is to provide a novel method for joining an electronic component to a circuit board.

【0006】

Another object of the present invention is to provide a novel joining method for joining an electronic component having a fine joining terminal structure to a circuit board. Still another object of the present invention is to provide a method of joining an electronic component to a circuit board that can be carried out in a simple process and can be adapted to a miniaturized terminal structure.

【0007】

Another object of the present invention is to provide a bonding method for bonding an electronic component to a circuit board and forming an insulating protective film that protects the bonded portion.

【0008】

[Means for solving problems]

According to one aspect of the present invention, a) a process of preparing a circuit board having a first metal joint portion and an electronic component having a second metal joint portion, and (b) the first metal joint metal portion. A step of holding the circuit board and the electronic component so that the second bonded metal portion and the second bonded metal portion are arranged in contact with each other or in close contact with each other, and forming a layer of a treatment liquid having electrolytic plating ability between them. And (c) the processing liquid between the circuit board and the electronic component is heated to form a plating layer on the first and second metal joints, and the first and second metal joints are formed. Provided is a step of forming an interconnect metal portion that electrically connects the portions, and a method of joining the circuit board having the portions and an electronic component.

【0009】

The present inventors have developed a method of connecting between joining terminals by arranging the joining terminals to be joined facing each other and selectively supplying a joining material on the joining terminals. The method of supplying the molten solder onto the bonding terminals with a soldering iron or the like is a bonding material supply method that follows this concept, but when trying to supply the molten solder onto the bonding terminals, the capacity of the bonding material that can be supplied is large. Easy to become. Plating can be considered as a method of supplying a bonding material having a capacity suitable for the dimensions of the bonding terminal.

【0010】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1A schematically shows the configuration of the ceramic substrate 10 which is a circuit board. The ceramic substrate 10 has a main ceramic substrate 1 including wiring on the ceramic plate or between laminated ceramic substrates, and a large number of bonding terminals 2 arranged on one surface of the main ceramic substrate 1.

【0011】

FIG. 1B schematically shows the configuration of the semiconductor integrated circuit device 20 which is an electronic component bonded to the ceramic substrate 10. The semiconductor integrated circuit device 20 includes a main semiconductor device 3 including semiconductor elements and wiring, and a large number of junction terminals 4 formed on the surface of the main semiconductor device 3.

【0012】

Both the junction terminal 2 of the ceramic substrate 10 and the junction terminal 4 of the semiconductor integrated circuit device 20 are subjected to final surface treatment by copper plating. The joining terminals 2 and 4 form a joining metal portion.

【0013】

As shown in FIG. 1 (C), a treatment liquid having electroless plating ability is dropped onto the region of the ceramic substrate 10 including the junction terminal corresponding to the semiconductor integrated circuit device 20 using a dispenser, and the treatment liquid layer 5 To form.

【0014】

As shown in FIG. 1 (D), the semiconductor integrated circuit device 20 is arranged to face each other on the circuit board 10. The circuit board 10 and the semiconductor integrated circuit device 20 are positioned and arranged in advance on the support plates 11 and 12 of the flip chip bonder. The junction terminal 4 of the semiconductor integrated circuit device 20 is arranged so as to be aligned with the junction terminal 2 of the circuit board 10, and a gap of, for example, about 100 μm to 200 μm is formed between them.

【0015】

FIG. 4 (A) is a table showing the components of the treatment liquid (1) that can be used when the surface of the joint terminal is copper-plated. These components are dissolved in water. This treatment liquid has a function of plating Sn by electroless plating, and the plating layer has a property of becoming thicker with time.

【0016】

In the state of FIG. 1D, the processing liquid 5, the circuit board 10, and the semiconductor integrated circuit device 20 are heated according to a predetermined temperature profile. FIG. 4B is a graph showing the temperature profile of the heating process. The horizontal axis shows the heating time in units, and the vertical axis shows the heating temperature in units of ° C. When the treatment liquid 5 is heated and reaches 60 ° C to 70 ° C, plating occurs on the surfaces of the bonding terminals 2 and 4 from the treatment liquid 5. As the temperature rises, the water content in the treatment liquid evaporates and the volume of the treatment liquid gradually decreases.

【0017】

FIG. 1 (E) shows a state in which the treatment liquid 5 has evaporated. A substantially uniform plating layer 6 is formed on the surfaces of the bonding terminals 2 and 4. Fillets 7 are formed in the opposite regions of the joining terminals 2 and 4 in a manner of bridging the joining terminals 2 and 4.

【0018】

The residual treatment liquid 5 fulfills functions such as oxide film removal, surface activation, and oxidation prevention in the same manner as ordinary flux. Since the metal plating layer that contributes to the bonding is supplied by an electrochemical mechanism, it is deposited only on the metal surface of the bonding terminal that is in contact with the treatment liquid. It is possible to supply the metal plating layer even to fine joints that cannot be supplied with solder paste.

【0019】

The heating step according to the temperature profile shown in Fig. 4 (B) continues heating up to about 250 ° C. In this heating step, the treatment liquid 5 evaporates and the formed plating layer melts. When the Sn plating layer 6 melts, more hot-dip galvanized metal gathers in the fillet portion 7, and the plating layer 6 in other portions reduces the thickness. In the intermediate region between the junction terminals 2 and 4, the surface of the fillet 7 has a shape that penetrates into the intermediate region. Further, the Cu layer on the final surface of the bonding terminals 2 and 4 reacts with the molten Sn layer to form an alloy.

【0020】

According to the temperature profile shown in FIG. 4B, the temperature is lowered while maintaining the relative positional relationship between the circuit board 10 and the semiconductor integrated circuit device 20. Due to the temperature drop, the metal once melted solidifies. In this way, the bonding terminals of the semiconductor integrated circuit device 20 which is an electronic component can be bonded onto the corresponding bonding terminals of the ceramic substrate 10 which is a circuit board without misalignment.

【0021】

The above example was executed to form a sample. The metal of the bonded fillet part 7 was analyzed by an electron probe microanalyzer (EPMA). Sn and Cu were detected in the fillet part, which is the joint part. It was confirmed that a Sn-Cu alloy was formed in the fillet portion.

【0022】

An example in which the final surface treatment of the bonding terminals 2 and 4 is tin-plated and the composition of the treatment liquid is changed will be described using the same configuration as in the above-described embodiment. In the configurations shown in FIGS. 1 (A) and 1 (B), the final surface treatment of the joint terminals 2 and 4 is tin plating.

【0023】

The composition of the treatment liquid 5 supplied in the step of FIG. 1 (C) is the treatment liquid (2) shown in FIG. 5 (A). This treatment liquid has a function of plating Bi. Similar to the treatment liquid (1), this plating liquid forms a plating layer whose thickness increases with time.

【0024】

The temperature profile in the heating step shown in FIG. 1 (D) shall be as shown in FIG. 5 (B). As in Fig. 4 (B), the horizontal axis shows time in units and the vertical axis shows temperature in units of ° C. In the heating step, heating is performed from room temperature to about 150 ° C, and the temperature is lowered after a lapse of a predetermined time. By performing the heating step shown in FIG. 5 (B), a bonding region can be formed by the Bi plating layer that joins the bonding terminals 2 and 4.

【0025】

This example was also actually executed to form a sample. An EPMA analysis was performed on the metal region that formed fillet 7. It was confirmed that fillet 7 is a Sn-Bi alloy.

【0026】

FIGS. 2 (A) to 2 (E) show an example using a bump (solder ball). FIG. 2A schematically shows the configuration of the circuit board 10. The circuit board 10 is the same as that of FIG. 1 (A) used in the above-described embodiment, and the outermost surface of the junction terminal 2 is copper-plated.

【0027】

FIG. 2B schematically shows the configuration of the semiconductor integrated circuit device 20 which is an electronic component. Similar to the above-described embodiment, the semiconductor integrated circuit device 20 includes a main semiconductor integrated circuit device 3, a junction terminal 4 on the main semiconductor integrated circuit device 3, and a solder bump 8 on the junction terminal 4. The outermost surface of the joint terminal 4 is gold-plated. Bump 8 is formed of Sn-3.5Ag, which is an alloy of 96.5% Sn and 3.5% Ag. The joining terminals 4 and bumps 8 can be considered together as a joining metal part.

【0028】

As shown in FIG. 2 (C), the processing liquid (1) shown in FIG. 4 (A) is supplied by a dispenser onto the region including the junction terminal of the semiconductor integrated circuit device 20 of the circuit board 10 and the corresponding junction terminal. , Sn plating layer was formed by treatment for 5 minutes. After that, the circuit board was washed with running water and then dried.

【0029】

Next, the treatment liquid is changed to the treatment liquid (2) shown in FIG. 5 (A), and the treatment liquid layer 5 is formed again as shown in FIG. 2 (C). As shown in FIG. 2 (D), the circuit board 10 is arranged on the support plate 11 of the flip chip bonder, and polyvinyl alcohol (PVA) is added to the treatment liquid (2) as a thickener on the predetermined region thereof. The treated solution 5 was added dropwise. The semiconductor integrated circuit device 20 supported on the other support plate 12 was aligned with the circuit board 10 and lowered to form a processing liquid layer 5 with the circuit board. At this time, the bump 8 and the junction terminal 2 of the circuit board 10 may be in contact with each other, or a gap of, for example, about 100 μm to 200 μm may be formed between them.

【0030】

In this state, heat treatment was performed according to the temperature profile shown in FIG. 5 (B). By this heat treatment, a Bi plating layer is formed on the surfaces of the bonding terminals 2 and 4 and the bump 8. By heating to about 150 ° C., the Bi-plated layer forms a Sn-plated layer of the bonding terminals 2 and 4 and a Sn-Bi alloy of the bump 8 and melts. FIG. 2 (E) shows the state in which the joining is completed.

【0031】

After cooling, EPMA analysis was performed on the metal of the fillet part 7. As a result of the analysis, it was confirmed that the fillet 7 was a Sn-Bi alloy. In the above-described embodiment, examples will be described in which the bonding terminals 2 and 4 are tin-plated and the treatment liquid having the composition shown in FIG. 6 (A) is used.

【0032】

The treatment liquid (3) shown in FIG. 6 (A) is a treatment liquid capable of performing In plating. This plating solution forms a plating layer whose thickness increases with time. The treatment liquid layer 5 is formed by using the treatment liquid (3) shown in FIG. 6 (A) in the state of FIG. 2 (C), and is shown in FIG. 6 (B) in the state shown in FIG. 2 (D). A heating step of the temperature profile was performed. By heating to about 130 ° C, the In-plated layer 6 is formed and alloyed with Sn of the connection terminals 2 and 4 and the solder bump 8, and the Sn-In alloy layer is formed and melted. After that, the temperature was lowered to obtain a bonded structure in which the surfaces of the bonded terminals 2, 4 and bumps 8 were covered with the bonded metal layer 6.

【0033】

After cooling, EPMA analysis of the fillet 7 part was performed. As a result of the analysis, it was confirmed that the fillet 7 was a Sn-In alloy. In the embodiment shown in FIG. 2, further parts replacement can be performed.

【0034】

As shown in FIG. 3A, after joining the electronic component 20 on the circuit board 10 with a plated alloy layer via the bump 8, the electrical characteristics of the electronic component 20 are inspected. For example, when the electronic component 20 is a semiconductor integrated circuit device, the circuit operation of the semiconductor integrated circuit device is checked.

【0035】

FIG. 3B shows the processing when the electronic component fails as a result of the inspection of the electronic component. The joint between the circuit board 10 and the electronic component 20 is heated to about 150 ° C with a hot plate, and the electronic component 20 is lifted off. The plated alloy layer that joined the electronic component 20 and the circuit board 10 is melted by heating to 150 ° C., and the electronic component 20 can be easily separated from the circuit board 10. After that, a new electronic component is joined to the circuit board 10 in the same manner as in the above-described embodiment. The newly joined electronic component is inspected again in the same manner as described above.

【0036】

FIG. 3C shows further processing when the inspected electronic component 20 passes the inspection. With the electronic component 20 bonded on the circuit board 10, heat treatment is performed by a hot plate or a flip chip bonder according to the temperature profile shown in FIG. 4 (B). By heating to about 250 ° C, the solder bump 8 melts and forms a connection portion 9 that firmly connects the connection terminal 2 and the connection 4. That is, the state shown in FIG. 2 (E) is the state of temporary joining, and the state shown in FIG. 3 (C) is the state of main joining.

【0037】

In the above-described embodiment, the treatment liquid initially used for bonding contains a metal that controls bonding. By interposing this treatment liquid in the joint portion, a bonded metal layer is formed by chemical plating (electroless plating) on the surfaces of both bonding terminals to be bonded. By continuously heating, the bonded plating layer forming the coating is melted, and by cooling, a bonded metal layer for bonding the bonded portions is formed.

【0038】

Since the metal that contributes to the bonding is supplied by an electrochemical mechanism, the plating layer is deposited only on the surface of the bonding terminal metal that is in contact with the treatment liquid. It is possible to supply as much metal plating layer as necessary to the fine joints, and unnecessary metal balls and the like do not remain after the joints.

【0039】

As the metal contained in such a treatment liquid, Sn, Pb, Zn, Bi, In, Ag and the like can be used. Further, two or more kinds of metals may be contained. A metal or alloy may be selected according to the desired bonding temperature.

【0040】

Further, the metal to be contained in the treatment liquid may be contained in the form of a salt or compound having an ion-forming ability in the treatment liquid such as sulfate, nitrate, oxide, chloride and sulfonate. Further, a metal in which a metal is dissolved in an acid such as hydrochloric acid, sulfuric acid or nitric acid or a mixed acid may be used.

【0041】

Further, a complexing agent for stabilizing metal ions, a reducing agent for reducing the oxide layer, a surfactant, a pH adjuster, a thickener and the like may be added to the treatment liquid. Generally, a material or the like that can be used for electroless plating can be used.

【0042】

The outermost surface of the bonded terminal is usually treated with layers such as Ni, Au, Pd, Sn, Sn-Pb, Sn-Bi, and Sn-Ag. All of these surface treatments are applied to protect the joint surface (antioxidation) and to ensure the wettability (solder wettability) at the time of joining. In the above-described embodiment, the surface treatment for joining and the joining can be performed simultaneously using one treatment liquid. There is almost no need to consider changes over time, oxidation, poor wetting, etc. after surface treatment.

【0043】

When the surface of the bonding terminal is finally treated with Sn and treated with a treatment liquid containing Bi, a Bi coating is formed on the Sn layer. The melting point of Sn is 232 ° C and the melting point of Bi is 271 ° C, but when Sn and Bi are mutually diffused to form a eutectic composition (0.42Sn-0.58Bi), the melting point is 139 ° C. That is, the joining temperature can be lowered to 140 ° C to 160 ° C. In this way, the bond can be formed at a temperature lower than the melting point of the metal coated as the bond layer.

【0044】

By the way, by containing an insulating resin in the treatment liquid, it is possible to carry out a step of forming a joint portion between terminals with a plating layer and at the same time carry out a step of coating the joint portion with a resin, thereby improving the insulating property. it can.

【0045】

Residues may remain at the junction after evaporation of the treatment solution solvent. This residue also contains ionic material and can cause insulation deterioration due to moisture absorption, but it is difficult to remove by cleaning if the gap between the circuit board and the semiconductor chip is very narrow. .. Therefore, it is conceivable to cover the residue with the resin contained in the treatment liquid and fix it to block moisture from the outside and maintain the insulating property.

【0046】

The resin contained in the treatment liquid can be used regardless of whether it is a thermoplastic resin or a thermosetting resin. Further, the thermoplastic resin and the thermosetting resin may be blended and used. In the case of a thermoplastic resin, the resin intervenes in the treatment liquid as a solid (powder), melts at a temperature lower than the bonding temperature, integrates (coats) with the evaporation of the treatment liquid solvent, and solidifies as the process temperature drops. It becomes a coating process.

【0047】

As the thermoplastic resin, polyester, polyethylene, polypropylene, vinyl acetate, styrene, polyvinyl chloride, polyamide, copolymers thereof, hydrophobic rosin and the like are used.

【0048】

Further, in the case of a thermosetting resin, either a solid resin or a liquid resin can be used. That is, a solid thermosetting resin is interposed in the treatment liquid as a powder, and a resin and a curing agent that melt, integrate, and cure at a temperature lower than the joining temperature are selected. In the case of a liquid thermosetting resin, it is a coating process in which the resin is dispersed in the treatment liquid and is dispersed as the solvent of the treatment liquid is evaporated, and the resin is integrated and cured. In both solid and liquid cases, it is necessary to use a curing agent that does not dissolve in the solvent of the treatment liquid.

【0049】

As the thermosetting resin, epoxy resin, polyimide resin, acrylic resin, phenol resin, and other modified resins are used. FIG. 7 shows an example using a treatment liquid in which an insulating resin is dispersed.

【0050】

7 (A) and 7 (B) show the schematic configurations of the circuit board 10 and the semiconductor integrated circuit device 20, respectively, and are the same as those of FIGS. 1 (A) and 1 (B) used in the first embodiment, respectively. It is a thing. The outermost surfaces of the joint terminals 2 and 4 are copper-plated.

【0051】

In FIG. 7C, a treatment liquid containing a component having electroless plating ability and an insulating resin is dropped onto a region of the circuit board 10 including the junction terminal corresponding to the semiconductor integrated circuit device 20 using a dispenser. Then, the treatment liquid layer 5 is formed. The insulating resin particles 30 are dispersed in the treatment liquid 5.

【0052】

FIG. 8 (A) is a table showing the composition of the treatment liquid (4) used in this example. The treatment liquid (4) is obtained by dispersing B-stage epoxy resin powder, which is a thermosetting resin, in the treatment liquid (1) used in the first embodiment, and has a function of plating Sn.

【0053】

As shown in FIG. 7D, the semiconductor integrated circuit device 20 is arranged to face each other on the circuit board 10. The circuit board 10 and the semiconductor integrated circuit device 20 are positioned and arranged in advance on the support plates 11 and 12 of the flip chip bonder. The junction terminal 4 of the semiconductor integrated circuit 20 is arranged so as to be aligned with the junction terminal 2 of the circuit board 10, and a gap of, for example, about 100 μm to 200 μm is formed between them.

【0054】

In the state of FIG. 7D, the processing liquid 5, the circuit board 10, and the semiconductor integrated circuit device 20 are heated according to a predetermined temperature profile. FIG. 8B is a graph showing the temperature profile of the heating process, which heats the temperature from room temperature to about 250 ° C. and lowers the temperature after a lapse of a predetermined time.

【0055】

Temperature profile As the temperature rises according to FIG. 8 (B), Sn plating occurs on the surfaces of the junction terminals 2 and 4. When the temperature is further raised and reaches a bonding temperature of about 250 ° C., the Sn forming the plating layer melts and gathers in a large amount in the region (fillet portion) between the bonding terminals 2 and 4. Further, the Cu layer on the final surface of the bonding terminals 2 and 4 reacts with the molten Sn layer to form an alloy. Then, as the temperature drops thereafter, the molten metal solidifies. In this way, a junction is formed between the circuit board 10 and the semiconductor integrated circuit device 20.

【0056】

On the other hand, in this heating step, the B-stage epoxy resin powder dispersed in the treatment liquid 5 is melted at a temperature lower than the joining temperature. The molten resin powder is integrated to cover the joint portion and its surroundings. When the temperature of the resin powder is further increased after the resin powder is melted and integrated, the curing of the resin is promoted. The process shown in FIG. 8 (B) proceeds further, and the temperature drops, the metal at the joint is solidified, the resin is cured, and a coating is formed.

【0057】

This example was carried out to form a sample. FIG. 7 (E) is a cross-sectional view of the bonded circuit board 10 and the bonded pad portion and the resin-coated portion 31 of the semiconductor integrated circuit device 20. The surface of the circuit board around the fillet portion 7, the plating layer 6, and the junction terminal 2 and the surface of the semiconductor integrated circuit device around the junction terminal 4 are covered with the resin layer 31, and the junction terminals 2 and 4 are filledet 7 without any misalignment. Was formed and joined normally. In addition, EPMA analysis was performed on the metal of the fillet portion 7, and it was confirmed that a Sn-Cu alloy was formed in the fillet 7.

【0058】

Insulation resistance between adjacent junction terminals is 1 x 10¹²It was Ω. An example in which the final surface treatment of the bonding terminals 2 and 4 is tin-plated and the composition of the treatment liquid is changed will be described using the same configuration as in the above-described embodiment.

【0059】

In FIGS. 7 (A) and 7 (B), the final surface treatment of the joint terminals 2 and 4 is tin plating. The composition of the treatment liquid 5 supplied in the step of FIG. 7 (C) is the treatment liquid (5) shown in FIG. 9 (A). The treatment liquid (5) is a treatment liquid (2) used in the second embodiment in which water-dispersible polyester resin powder, which is a thermoplastic resin, is dispersed, and has a function of plating Bi.

【0060】

The temperature profile in the heating step shown in FIG. 7 (D) is as shown in FIG. 9 (B), and the temperature is heated from room temperature to about 150 ° C. and lowered after a lapse of a predetermined time. As the temperature rises according to the temperature profile FIG. 9 (B), Bi plating occurs on the surfaces of the junction terminals 2 and 4. When the temperature is further raised to near the bonding temperature of about 150 ° C, the Sn layer on the final surface of the bonding terminals 2 and 4 reacts with the Bi layer to form an alloy, melt it, and collect a large amount at the fillet portion 7. As the temperature drops thereafter, the molten metal solidifies. In this way, a junction is formed between the circuit board 10 and the semiconductor integrated circuit device 20.

【0061】

On the other hand, in this heating step, the water-dispersed polyester resin powder dispersed in the treatment liquid 5 melts at a temperature lower than the joining temperature. As the temperature rises, the solvent (moisture) in the treatment liquid evaporates, but the resin dispersed in the treatment liquid does not evaporate. Therefore, after the water content in the treatment liquid evaporates, the molten resin is left behind in the region between the circuit board 10 and the semiconductor integrated circuit device 20. The left-over resin is integrated to cover the joint portion and its surroundings. The process shown in FIG. 9B proceeds further, and as the temperature drops, the resin solidifies and a coating is formed.

【0062】

This example was carried out to form a sample. The joint portion and its surroundings were covered with a resin layer 31, and the joint terminals 2 and 4 formed fillets 7 without any misalignment and were normally joined. In addition, EPMA analysis was performed on the metal of the fillet part 7, and it was confirmed that a Sn-Bi alloy was formed in the fillet 7. Insulation resistance between adjacent junction terminals is 1 x 10¹²It was Ω.

【0063】

Using the same configuration as in the above embodiment, the final surface treatment of the joint terminal 2 is copper plating, the final surface treatment of the joint terminal 4 is tin plating, the composition of the treatment liquid is changed, and a reflow furnace is used for the heating process. The example that was used will be described.

【0064】

In FIGS. 7A and 7B, the final surface treatment of the joint terminal 2 is copper plating, and the final surface treatment of the joint terminal 4 is tin plating. Here, the processing liquid (1) shown in FIG. 4 (A) is applied to the region including the junction terminal of the semiconductor integrated circuit device 20 of the circuit board 10 shown in FIG. 7 (A) and the junction terminal corresponding to FIG. 2 (C). ), A Sn-plated layer was formed on the junction terminal 2 of the circuit board 10 by supplying the mixture with a dispenser and treating for 5 minutes. After that, the circuit board was washed with running water and then dried.

【0065】

In the process of FIG. 7C, the treatment liquid 5 was dropped onto the region of the circuit board 10 including the junction terminal corresponding to the semiconductor integrated circuit device 20. As the composition of the treatment liquid, the treatment liquid (5) shown in FIG. 9 (A) was used, and polyvinyl alcohol (PVA) was added as a thickener to the treatment liquid (5).

【0066】

As shown in FIG. 7D, the semiconductor integrated circuit 20 is arranged to face each other on the circuit board 10. The circuit board 10 and the semiconductor device 20 are positioned and arranged on the support plate 11 and the jig 12, respectively. The junction terminal 4 of the semiconductor integrated circuit 20 is arranged so as to be aligned with the junction terminal 2 of the circuit board 10, and a gap of, for example, about 100 μm to 200 μm is formed between them.

【0067】

In this state, heat treatment was performed according to the temperature profile shown in FIG. 9 (C). In this heating step, the temperature is raised from room temperature to about 150 ° C., and the temperature is lowered after a predetermined time has elapsed. In this heating step, the Bi-plated layer forms a joint between the joint terminals 2 and 4, and the water-dispersible polyester resin forms an insulating coating that covers the joint and its periphery.

【0068】

This example was carried out to form a sample. The joint portion and its surroundings were covered with the resin layer 31, and the fillet 7 was formed without any misalignment, and the joint was normally joined. In addition, EPMA analysis was performed on the metal of the fillet part 7, and it was confirmed that a Sn-Bi alloy was formed in the fillet 7. Insulation resistance between adjacent junction terminals is 1 x 10¹²It was Ω.

【0069】

Using the same configuration as in the above embodiment, the final surface treatment of the joining terminal 2 is tin-plated, the final surface treatment of the joining terminal 4 is tin-plated, the composition of the treatment liquid is changed, and a flip-chip bonder is used in the heating process. Examples used will be described.

【0070】

In FIGS. 7 (A) and 7 (B), the final surface treatment of the joint terminals 2 and 4 is tin plating. The treatment liquid 5 supplied in the step of FIG. 7 (C) is defined as the treatment liquid (6) having the composition shown in FIG. 10 (A). The treatment liquid (6) is a treatment liquid (3) used in the fourth embodiment in which hydrophobic rosin (KE-100) powder, which is a thermoplastic resin, is dispersed, and has a function of plating In. ..

【0071】

As shown in FIG. 7D, the semiconductor integrated circuit device 20 is arranged to face each other on the circuit board 10. The circuit board 10 and the semiconductor integrated circuit device 20 are positioned and arranged in advance on the support plates 11 and 12 of the flip chip bonder. The junction terminal 4 of the semiconductor integrated circuit 20 is arranged so as to be aligned with the junction terminal 2 of the circuit board 10, and a gap of, for example, about 100 μm to 200 μm is formed between them.

【0072】

In the state of FIG. 7D, the processing liquid 5, the circuit board 10, and the semiconductor integrated circuit device 20 are heated according to a predetermined temperature profile. FIG. 10B is a graph showing the temperature profile of the heating process, which heats the temperature from room temperature to about 130 ° C. and lowers the temperature after a lapse of a predetermined time.

【0073】

Temperature profile As the temperature rises according to FIG. 10 (B), In plating occurs on the surfaces of the junction terminals 2 and 4. When the temperature is further raised to near the bonding temperature of about 130 ° C, the Sn layer on the final surface of the bonding terminals 2 and 4 reacts with the In layer to form an alloy, melt it, and collect a large amount at the fillet portion 7. As the temperature drops thereafter, the molten metal solidifies. In this way, a junction is formed between the circuit board 10 and the semiconductor integrated circuit device 20.

【0074】

On the other hand, in this heating step, the hydrophobic rosin powder dispersed in the treatment liquid 5 melts at a temperature lower than the joining temperature. The molten hydrophobic rosin is integrated to cover the joint portion and its surroundings, as in the case of the water-dispersed polyester resin in the seventh embodiment, which is also a thermoplastic resin. The process shown in FIG. 9B proceeds further, and as the temperature drops, the resin solidifies and a coating is formed.

【0075】

This example was carried out to form a sample. The joint portion and its surroundings were covered with resin 31, and fillets 7 were formed without any misalignment, and the joints were normally joined. In addition, EPMA analysis was performed on the metal of the fillet part 7, and it was confirmed that a Sn-In alloy was formed in the fillet 7.

【0076】

Although the present invention has been described above according to Examples, the present invention is not limited thereto. For example, the electronic components to be joined are not limited to semiconductor integrated circuit devices, but may be other electronic components such as chip resistors and chip capacitors. It is also possible to join the circuit board and the circuit board. It will be obvious to those skilled in the art that various other changes, improvements and combinations are possible.

【0077】

Hereinafter, the features of the present invention will be added. (Appendix 1) (1) (a) A step of preparing a circuit board having a first metal joint portion and an electronic component having a second metal joint portion, and (b) the first metal joint metal portion. A step of holding the circuit board and the electronic component so that the second bonded metal portion is arranged in contact with or close to each other and facing each other, and forming a layer of a treatment liquid having electrolytic plating ability between them. , (C) The treatment liquid between the circuit board and the electronic component is heated to form a plating layer on the first and second metal joints, and the first and second metal joints are formed. A method of joining a circuit board and an electronic component having a step of forming an interconnect metal part that electrically connects the two.

【0078】

(Appendix 2) The circuit board and the electrons in which the step (a) has a metal layer containing at least one of the constituent elements of the interconnect metal portion as the outermost surface of the first and second bonded metal portions. Preparation of components The method of joining the circuit board and electronic components described in Appendix 1.

【0079】

(Appendix 3) The method for joining a circuit board and an electronic component according to Appendix 1 or 2, wherein the step (c) is continuously performed in a series of temperature profiles. (Appendix 4) (2) The method for joining a circuit board and an electronic component according to Appendix 1 or 2, wherein the step (c) forms an interconnected metal portion, melts, and solidifies.

【0080】

(Appendix 5) (3) The surface is formed by alloying the treatment liquid with a metal having a melting point lower than the melting point of the metal on the surface of the first and second bonded metal portions, or a metal on the surface. The method for joining a circuit board and an electronic component according to any one of Supplementary note 1 to 4, which comprises a metal capable of forming an alloy having a melting point lower than the melting point of the metal.

【0081】

(Appendix 6) The method for joining a circuit board and an electronic component according to any one of Appendix 1 to 5, wherein the treatment liquid further has a flux action. (Appendix 7) The step (a) prepares a joining terminal having a bump as a first or second joining metal portion, and the step (c) temporarily fixes the electronic component to the circuit board. The method for joining a circuit board and an electronic component according to any one of Supplementary note 1 to 6, which is a step and further includes (d) a step of performing a functional test of the electronic component.

【0082】

(Appendix 8) (4) Further, (e) a step of heating the interconnect metal portion and removing the electronic component from the circuit board when the result of the step (d) is poor, and (f). ) The method of joining the circuit board and the electronic component according to Appendix 7, which includes a step of attaching another electronic component to the circuit board after the step (e).

【0083】

(Appendix 9) (4) Further, (g) If the result of the step (d) is good, the interconnect metal portion is melted together with the bump and then solidified to attach the electronic component to the circuit board. The method of joining the circuit board and the electronic component according to Appendix 7, which includes the step of final fixing.

【0084】

(Appendix 10) (5) The circuit board and electronic component according to any one of Appendix 1 to 6, wherein the treatment liquid contains resin particles and a resin layer is formed in the step (c). How to join with.

【0085】

(Appendix 11) Further, in the step (c), a plating layer covering the surfaces of the first and second bonded metal portions is formed, and the resin layer covers the interconnecting metal portion and the plating layer. The method for joining a circuit board and an electronic component according to Appendix 10, which is formed in 1.

【0086】

(Appendix 12) Further, in the step (c), the resin layer is formed on the surface of a portion of the circuit board other than the first bonded metal portion and a portion of the electronic component other than the second bonded metal portion. The method for joining a circuit board and an electronic component according to Appendix 11, which is also formed on at least a part of the surface.

【0087】

(Appendix 13) The treatment liquid contains resin particles, and in the step (c), the resin particles are melted, integrated, and solidified to form a resin layer. A method for joining a circuit board and an electronic component according to the above.

【0088】

(Appendix 14) The method for joining a circuit board and an electronic component according to any one of Appendix 10 to 13, wherein the resin particles are made of a thermoplastic resin. (Appendix 15) The method for joining a circuit board and an electronic component according to any one of Appendix 10 to 13, wherein the resin particles are made of a thermosetting resin.

【0089】

(Appendix 16) The bonding between the circuit board and the electronic component according to any one of Appendix 10 to 13, wherein the resin particles are a mixture of the resin particles made of a thermoplastic resin and the resin particles made of a thermosetting resin. Method.

【0090】

(Appendix 17) The base circuit board having the first metal joint portion, the electronic component having the second metal joint metal portion, and the surfaces of the first and second metal joint metal parts are covered, and the first and second metal joint parts are covered. A circuit board having an interconnected metal portion having a shape in which a surface enters the intermediate region in an intermediate region between the bonded metal portions of the above.

【0091】

(Appendix 18) The circuit board according to Appendix 17, which has a resin layer covering the interconnect metal portion. (Appendix 19) A circuit board having a first metal joint, an electronic component having a second metal joint, and the surfaces of the first and second metal joints are covered, and the first and second metal parts are covered. A circuit board structure having an interconnected metal portion having a shape in which a surface enters the intermediate region in an intermediate region between the bonded metal portions.

【0092】

(Appendix 20) The circuit board structure according to Appendix 19, which has a resin layer covering the interconnected metal portion.

【0093】

[Effect of the invention]

As described above, according to the present invention, a new method for joining between joining terminals is provided.

【0094】

The terminals to be bonded can be arranged so as to face each other, and a bonded metal layer can be selectively formed on the bonded terminals. Further, it is possible to provide a joining method in which parts can be easily replaced.

【0095】

The joint portion can be coated with an insulating resin layer.

[Simple explanation of drawings]

[Figure 1]

It is the schematic sectional drawing of the circuit board and the electronic component for demonstrating the Example of this invention.

[Figure 2]

It is the schematic sectional drawing of the circuit board and the electronic component for demonstrating the joining method by another Example of this invention.

[Fig. 3]

It is sectional drawing which shows the further development of the Example shown in FIG.

[Fig. 4]

It is a table which shows the composition of the treatment liquid (1), and the graph which shows the temperature profile.

[Fig. 5]

The table showing the composition of the treatment liquid (2) and the graph showing the temperature profile.

[Fig. 6]

It is a table which shows the composition of a treatment liquid (3), and a graph which shows a temperature profile.

[Fig. 7]

It is the schematic sectional drawing of the circuit board and the electronic component for demonstrating the joining method by still another Example of this invention.

[Fig. 8]

It is a table which shows the composition of a treatment liquid (4), and a graph which shows a temperature profile.

[Fig. 9]

It is a table which shows the composition of a treatment liquid (5), and a graph which shows a temperature profile.

[Fig. 10]

It is a table which shows the composition of a treatment liquid (6), and a graph which shows a temperature profile.

[Explanation of symbols]

1 Main ceramic substrate 2 Bonded terminal 3 Main semiconductor integrated circuit equipment 4 Junction terminal 5 Treatment liquid 6 Plating layer 7 fillets 8 bumps 10 Circuit board 11, 12 Support plate 20 Electronic components 30 resin grains 31 Resin layer