Substrate processor and manufacturing method of semiconductor device

【0001】

[Technical field to which the invention belongs]

The present invention relates to a substrate processing technology, for example, in a method for manufacturing a semiconductor integrated circuit device (hereinafter referred to as IC), a polysilicon or silicon nitride film is formed on a semiconductor wafer (hereinafter referred to as a wafer) in which a semiconductor integrated circuit is built. It is related to what is effective for depositing etc.

【0002】

In the method of manufacturing ICs, a batch type vertical hot wall type decompression CVD apparatus (hereinafter referred to as a CVD apparatus) is widely used for depositing a CVD film such as polysilicon or a silicon nitride film on a wafer. Conventional CVD devices of this type include, for example, a process tube composed of an inner tube and an outer tube surrounding the inner tube and installed vertically, as shown in Japanese Patent Application Laid-Open No. 2000-311862. A boat that holds a single wafer and carries it into the inner tube, a gas introduction nozzle that introduces the raw material gas into the inner tube, an exhaust port that exhausts the inside of the process tube to reduce the pressure, and is laid outside the process tube. It is equipped with a heater unit that heats the inside of the process tube, and the gas introduction nozzle is provided with multiple spouts corresponding to each wafer held in the boat, and an exhaust hole is opened on the side wall of the inner tube. There is something that is.

【0003】

In this CVD device, a plurality of wafers are long aligned and held by a boat and then carried into the inner tube from the furnace port at the lower end (boat loading), and the raw material gas is introduced into the inner tube by a gas introduction nozzle. At the same time, the inside of the process tube is heated by the heater unit, so that the CVD film is deposited on the wafer. At this time, the raw material gas horizontally ejected from the plurality of outlets of the gas introduction nozzle flows between the upper and lower wafers held horizontally by the boat and comes into contact with the surface of the wafer, and is opened in the inner tube. It is exhausted from the exhaust hole to the outside of the inner tube by the exhaust force of the exhaust port.

【0004】

[Problems to be Solved by the Invention]

However, in the above-mentioned CVD apparatus, when a part of the raw material gas exhausted from the exhaust hole flows between the inner tube and the outer tube and local stagnation occurs, foreign matter adheres to the outer peripheral surface of the inner tube. There is a problem that particles are likely to be generated. For example, when forming a polysilicon film, monosilane (SiH) in a high temperature region₄), When the period of stay is long, the decomposition reaction in the gas phase proceeds excessively, so that the silicon becomes powdery and precipitates, and a brown by-product adheres to the outer peripheral surface of the inner tube. Was confirmed. This by-product is a polymerization bond of silylene, an intermediate product of silane [(SiH).₄) n]. Then, when the foreign matter adhering to the outer peripheral surface of the inner tube is peeled off and flows back into the processing chamber, it becomes particles that contaminate the surface of the wafer.

【0005】

An object of the present invention is to provide a substrate processing technique capable of preventing foreign matter from adhering to the outer peripheral surface of the side wall of the processing chamber.

【0006】

[Means for solving problems]

The substrate processing apparatus according to the present invention includes a processing chamber that processes a plurality of substrates, a boat that holds the plurality of substrates and carries them into the processing chamber, and a gas introduction port that introduces processing gas into the processing chamber. An exhaust hole opened on the side wall of the processing chamber to exhaust the processing chamber and an exhaust duct covering the exhaust hole are provided, and the width D of the exhaust duct in the circumferential direction and the circumference of the exhaust hole are provided. The feature is that the ratio with the width of the direction is set to "70" or more.

【0007】

In the above means, the gas is introduced into the treatment chamber through the gas inlet. Since the gas introduced into the treatment chamber is exhausted from the exhaust holes provided on the side wall of the treatment chamber, the gas flowing through the treatment chamber is in a state of flowing parallel to each substrate. By flowing in parallel to each substrate, the gas comes into uniform contact with the entire surface of each substrate, so that the processing state in each substrate becomes uniform. Since the processing gas exhausted from the exhaust hole does not flow along the outer peripheral surface of the side wall of the processing chamber by flowing through the exhaust duct, it is possible to prevent the processing gas from coming into contact with the outer peripheral surface of the side wall of the processing chamber. it can.

【0008】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

【0009】

In the present embodiment, as shown in FIG. 1, the substrate processing apparatus according to the present invention is configured as a CVD apparatus (batch type vertical hot wall type decompression CVD apparatus).

【0010】

The CVD apparatus shown in FIG. 1 has a vertical process tube 1 that is vertically arranged and fixedly supported so that the center line is vertical, and the process tube 1 includes an inner tube 2 and an outer tube 3. It is composed of. Both the inner tube 2 and the outer tube 3 are integrally molded into a cylindrical shape using a highly heat-resistant material such as quartz glass or silicon carbide (SiC). The inner tube 2 is formed in a cylindrical shape with the upper end closed and the lower end open, and the hollow portion of the inner tube 2 has a processing chamber 4 in which a plurality of wafers held in a long aligned state by a boat are carried. Is forming. The inner diameter of the inner tube 2 is set to be larger than the maximum outer diameter of the wafer 10 to be handled. The outer tube 3 is formed in a cylindrical shape with the upper end closed and the lower end open, similar to the inner tube 2 in a large size, and is covered with concentric circles so as to surround the outside of the inner tube 2. A gap 5 is formed between the inner tube 2 and the outer tube 3 in the shape of a circular ring having a constant width.

【0011】

The lower end between the inner tube 2 and the outer tube 3 is hermetically sealed by a manifold 6 formed in a circular ring shape, and the manifold 6 is used for maintenance and inspection work and cleaning work on the inner tube 2 and the outer tube 3. Therefore, it is detachably attached to the inner tube 2 and the outer tube 3. The process tube 1 is in a vertically mounted state by supporting the manifold 6 in the housing of the CVD apparatus (not shown). An exhaust port 7 is provided in a part of the side wall of the manifold 6, and the exhaust port 7 is connected to an exhaust device (not shown) so that the inside of the processing chamber 4 can be depressurized to a predetermined degree of vacuum. Has been done. As shown in FIG. 2 (b), an exhaust duct portion 8 is continuously provided in the exhaust port 7, and the exhaust duct portion 8 is connected to the exhaust duct 26 formed in the outer tube 3 to be described later. It is configured in.

【0012】

A seal cap 9 that closes the lower end opening is brought into contact with the manifold 6 from the lower side in the vertical direction. The seal cap 9 is formed in a disk shape substantially equal to the outer diameter of the outer tube 3, and is configured to be vertically raised and lowered by a boat elevator (not shown) installed vertically outside the process tube 1. ing. A boat 11 for holding the wafer 10 as an object to be processed is vertically erected and supported on the center line of the seal cap 9. The boat 11 is provided with a pair of upper and lower end plates 12 and 13 and a plurality of holding members 14 erected between the both end plates 12 and 13 and arranged vertically, and each holding member 14 has a large number of strips. The holding grooves 15 of the above are arranged at equal intervals in the longitudinal direction and are buried so as to open opposite to each other. By inserting the circular peripheral edge of the wafer 10 between the holding grooves 15 of the same stage of the plurality of holding members 14, the plurality of wafers 10 are aligned and held horizontally and centered on each other. A pair of auxiliary end plates 16 and 17 are vertically supported and arranged between the boat 11 and the seal cap 9 by a plurality of auxiliary holding members 18, and each auxiliary holding member 18 holds a large number of strips. Groove 19 is buried.

【0013】

On the outside of the outer tube 3, heater units 20 that heat the inside of the process tube 1 to a uniform or predetermined temperature distribution are concentrically installed so as to surround the outer tube 3, and the heater unit 20 is a CVD device. It is in a vertically installed state by being supported by the housing.

【0014】

As shown in FIGS. 1 and 2, a channel-shaped spare chamber 21 is radially outwardly located at a position 180 degrees opposite to the exhaust port 7 on the side wall of the inner tube 2 which is the side wall of the processing chamber 4. It is formed so as to bulge and extend vertically, and a gas introduction nozzle 22 is laid inside the spare chamber 21 so as to extend vertically. The inlet portion 23 of the gas introduction nozzle 22 penetrates the side wall of the manifold 6 outward in the radial direction and protrudes to the outside of the process tube 1, and the inlet portion 23 includes a raw material gas supply device, a nitrogen gas supply device, etc. (FIG. Not shown) is connected. A plurality of ejection ports 24 as gas inlets are vertically arranged and opened in the gas introduction nozzle 22, and the number of the ejection ports 24 groups is matched with the number of wafers 10 held in the boat 11. The height position of each spout 24 is set so as to face the space between the vertically adjacent wafers 10 and 10 held by the boat 11.

【0015】

As shown in FIGS. 1 and 3, an exhaust slit 25 is vertically elongated at a position 180 degrees opposite to the spare chamber 21 on the side wall of the inner tube 2, that is, a position on the exhaust port 7 side. The length of the exhaust slit 25 is set to extend longer than the total length of the wafer 10 group held by the boat 11. An exhaust duct 26 that covers the exhaust slit 25 is projected from the outer periphery of the side wall of the inner tube 2. The exhaust duct 26 is formed in a gutter shape having a substantially rectangular cross section, and the radial dimension of the exhaust duct 26 is set to be equal to or less than the radial dimension of the gap 5 between the inner tube 2 and the outer tube 3. .. The ratio of the circumferential width D of the exhaust duct 26 and the circumferential width S of the exhaust slit 25 shown in FIG. 2A is set to 70, that is, D / S = 70. The lower end surface of the exhaust duct 26 is in contact with the upper surface of the exhaust duct portion 8 of the manifold 6, and the inside of the exhaust duct 26 is exhausted by the exhaust port 7 through the exhaust duct portion 8. Further, as shown in FIG. 2B, a nitrogen gas supply pipe 27 for supplying nitrogen gas to the gap 5 is connected to the side wall of the manifold 6.

【0016】

Next, the operation and effect of the CVD apparatus according to the above configuration will be described by taking a film forming step in the method for manufacturing an IC according to the embodiment of the present invention as an example.

【0017】

In the wafer charging step, the wafer 10 is inserted into the boat 11 so as to engage between the holding grooves 15 of the holding member 14 at a plurality of locations where the circular peripheral edges face each other, and the circular peripheral edges at the plurality of locations are formed. It is loaded (charged) and held so that it can be engaged with each holding groove 15 to support its own weight. The plurality of wafers 10 are centered and aligned parallel and horizontally to each other in the charging state of the boat 11.

【0018】

In the boat loading step, the boat 11 in which a plurality of wafers 10 are aligned and held is carried into the processing chamber 4 of the inner tube 2 (boat loading) so as to be delivered by the boat elevator, and is carried into the processing chamber 4 in FIG. It is retained as shown in Figure 3. In this state, the seal cap 9 seals the processing chamber 4.

【0019】

Subsequently, in the depressurization step, the inside of the process tube 1 is decompressed to a predetermined degree of vacuum (for example, 200 Pa) by the exhaust force acting on the exhaust port 7, and in the temperature rise step, the inside of the process tube 1 is a heater unit. The temperature is raised to a predetermined temperature (for example, 400 ° C.) by 20.

【0020】

Next, in the film forming step, when the predetermined raw material gas 30 is supplied to the inlet portion 23 of the gas introduction nozzle 22 at normal pressure (atmospheric pressure), the raw material gas 30 circulates through the gas introduction nozzle 22 and a plurality of raw material gases It is introduced from the spout 24 into the processing chamber 4 of the inner tube 2. For example, when doped polysilicon is diffused, the raw material gas 30 is monosilane (SiH).₄ ) And phosphine (PH)₃ ) Is introduced into the processing room 4. Further, as shown in FIG. 2B, nitrogen gas 31 is supplied to the gap 5 by the nitrogen gas supply pipe 27.

【0021】

The raw material gas 30 introduced into the processing chamber 4 flows out to the exhaust duct 26 from the exhaust slit 25 formed vertically elongated on the side wall of the inner tube 2, and the exhaust gas opened in the manifold 6 via the exhaust duct portion 8. Exhaust from mouth 7. At this time, since the gas introduction nozzle 22 and the exhaust slit 25 are arranged so as to face each other at a distance of 180 degrees, the raw material gas 30 ejected from each outlet 24 of the gas introduction nozzle 22 is in the processing chamber. 4 flows horizontally toward the exhaust slit 25 on the opposite side, and flows parallel to each wafer 10. Moreover, since each of the plurality of ejection ports 24 is arranged so as to face each other between the wafers 10 and 10 adjacent to each other on the upper and lower sides, the raw material gases 30 ejected from the respective ejection ports 24 are adjacent to each other on the upper and lower sides. It flows into each of the spaces between the matching wafers 10 and 10 and flows reliably in parallel. A CVD film is deposited on the surface of the wafer 10 by the CVD reaction of the raw material gas 30 that flows in parallel in the space between the wafers 10 and 10 adjacent to each other while being in contact with the surface of the wafer 10. For example, when monosilane and phosphine are introduced, a doped polysilicon film is deposited on the wafer 10. At this time, since the raw material gas 30 is in uniform contact with each other over the entire surface of each wafer 10, the deposition state of the CVD film is uniform in both the film thickness and the film quality in each wafer 10.

【0022】

In the present embodiment, the exhaust hole is composed of an elongated exhaust slit 25, and the ratio of the circumferential width D of the exhaust duct 26 to the circumferential width S of the exhaust slit 25 is "70", that is, "D /". By setting "S = 70", a constant flow rate can be generated over the entire length of the exhaust slit 25, so that the film thickness and film quality formed on each wafer 10 of the wafer 10 group held by the boat 11. Is uniform over the entire length of the boat 11 in the wafer 10 group.

【0023】

Here, a simulation of the gas flow velocity above and below the exhaust slit 25 is performed using the ratio of the circumferential width D of the exhaust duct 26 to the circumferential width S of the exhaust slit 25 (hereinafter referred to as D / S) as a parameter. , The graph shown in FIG. 4 was obtained. In FIG. 4, the horizontal axis is the D / S, and the vertical axis is the ratio of the gas flow rate A at the upper part of the exhaust slit 25 to the gas flow rate B at the lower part (hereinafter referred to as A / B). The uniformity of the flow to be made is taken. The conditions in the simulation are as follows. The radial dimension of the exhaust duct 26 is 15 mm. The length of the exhaust slit 25 is substantially the same as the length of the wafer group held by the boat 11. The pressure in the processing chamber is 300 Pa. The type of gas is silane. The flow velocity of the gas introduction nozzle 22 is 400 cc / min (cubic centimeter per minute), 800 cc / min, 1200 cc / min.

【0024】

According to Fig. 4, the D / S when the gas flows uniformly through the exhaust slit 25 at any of the flow rates of 400 cc / min, 800 cc / min, and 1200 cc / min, that is, when the A / B becomes "1", is It is understood that it is "70". Therefore, when "D / S = 70" is set, the raw material gas 30 flows through the exhaust slit 25 with a constant flow rate over the entire length above and below it.

【0025】

Then, in the present embodiment, since the exhaust slit 25 is covered with the exhaust duct 26, the raw material gas 30 exhausted from the exhaust slit 25 flows out into the gap 5 between the inner tube 2 and the outer tube 3. Since there is no such thing, silane by-products do not adhere to the outer peripheral surface of the inner tube. Therefore, the phenomenon that the by-products adhering to the outer peripheral surface of the inner tube 2 are peeled off and flow back to the processing chamber 4 does not occur, and the risk of contamination of the surface of the wafer 10 due to the scattering of the particles should be eliminated. Can be done. Further, the leakage of the raw material gas 30 from the exhaust duct 26 is surely prevented by the nitrogen gas 31 supplied from the nitrogen gas supply pipe 27 to the gap 5.

【0026】

After the desired CVD film (for example, doped polysilicon film) has been deposited as described above, the processing chamber 4 is opened by lowering the seal cap 9 in the boat unloading step, and the boat 11 is opened. The 10 groups of processed wafers are carried out from the processing chamber 4 to the outside of the process tube 1 (boat unloading) while being held in the processing chamber 4.

【0027】

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof.

【0028】

For example, the process tube is not limited to the inner tube and the outer tube, and the outer tube may be omitted.

【0029】

Not limited to setting D / S = 70, for example, if A / B = 1 ± 5%, D / S = 60 or more may be set.

【0030】

The exhaust hole is not limited to the exhaust slit which is a series of elongated holes, and may be formed by a plurality of holes. Further, the width S in the circumferential direction of the exhaust hole composed of the exhaust slit and the plurality of holes is not limited to being set to be the same over the entire length, but may be increased or decreased.

【0031】

The width D in the circumferential direction and the depth in the radial direction of the exhaust duct are not limited to being set to be the same over the entire length, but may be increased or decreased.

【0032】

The number of ejection ports provided in the gas introduction nozzle is not limited to matching the number of wafers to be processed, but can be increased or decreased according to the number of wafers to be processed. For example, the spouts are not limited to being arranged so as to face each other between adjacent wafers on the top and bottom, and may be arranged every two or three wafers.

【0033】

The gas introduction nozzle is not limited to being laid in the spare chamber bulged in the inner tube, and may be laid along the inner circumference of the side wall of the treatment chamber. Further, the gas introduction port is not limited to the gas introduction nozzle, but may be opened in the manifold or the processing room.

【0034】

In the above embodiment, the case where the processing is applied to the wafer has been described, but the processing target may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk, or the like.

【0035】

In the above-described embodiment, the deposition of the doped polysilicon film has been described, but it can be applied to all methods for forming a CVD film such as a doped polysilicon oxide film and a silicon nitride film. Further, the method for manufacturing a semiconductor device according to the present invention can be applied to all heat treatment steps in the method for manufacturing a semiconductor device such as an oxide film forming step and a diffusion step.

【0036】

In the above embodiment, the case where it is applied to the batch type vertical hot wall type decompression CVD apparatus has been described, but the present invention is not limited thereto, and the horizontal hot wall type decompression CVD apparatus, the oxide film forming apparatus, the diffusion apparatus and other heat treatments are used. It can be applied to all substrate processing equipment such as equipment (furnace).

【0037】

[Effect of the invention]

As described above, according to the present invention, it is possible to prevent foreign matter from adhering to the outer peripheral surface of the side wall of the processing chamber.

[Simple explanation of drawings]

FIG. 1 is a front sectional view showing a CVD apparatus according to an embodiment of the present invention.

FIG. 2A is a plan sectional view taken along line aa in FIG. 1, and FIG. 2B is a sectional view taken along line bb in FIG.

FIG. 3 is a side sectional view taken along the line cc of FIG.

FIG. 4 is a graph showing the relationship between D / S and gas flow uniformity.

[Explanation of symbols]

1 ... process tube, 2 ... inner tube, 3 ... outer tube, 4 ... processing chamber, 5 ... gap, 6 ... manifold, 7 ... exhaust port, 8.. Exhaust duct, 9 ... seal cap, 10 ... wafer (board), 11 ... boat, 12, 13 ... end plate, 14 ... holding member, 15 ... holding groove, 16, 17 ... Auxiliary end plate, 18 ... Auxiliary holding member, 19 ... Holding groove, 20 ... Heater unit, 21 ... Spare chamber, 22 ... Gas introduction nozzle, 23 .. .Inlet, 24 ... spout (gas inlet), 25 ... exhaust slit (exhaust hole), 26 ... exhaust duct, 27 ... nitrogen gas supply pipe, 30 ... raw material gas, 31 ... Nitrogen gas.