JP2003045863A - Substrate processing system and method for manufacturing semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an IC while suppressing increase in manufacture cost and variation in the film thickness. SOLUTION: A heater 20 for heating a wafer group W held on a boat 11 in a processing tube 1 is zoned into first stage heater section 21 through seventh stage heater section 27 so that heating control is performed in correspondence with a carrier containing the wafer group W. When a smaller number of wafers W than the maximum number of wafers holderable on the boat 11 are processed, the wafers W are held being placed closely to the bottom of the boat 11 and the third heater section 23 through the sixth heater section 26 corresponding to the wafer W group of the boat 11 serve as a soaking zone while the first heater section 21, the second heater section 22 and the seventh heater section 27 serve as a thermal insulation zone. Since reaction in the thermal insulation zone can be prevented from having an effect on the soaking zone, accuracy of film thickness equal to that of an ordinary batch can be attained without using a dummy wafer causing cost increase even when the number of wafers being processed is decreased and an idle space is formed in the processing tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus and a semiconductor device manufacturing method, for example, a semiconductor wafer (hereinafter referred to as a wafer) as a substrate on which a semiconductor integrated circuit device (hereinafter referred to as IC) is formed. ) To a low-pressure CVD apparatus for depositing (depositing) silicon nitride (Si ₃ N ₄ ) or polysilicon, or for reflow for carrier activation or flattening after ion implantation as well as oxidation treatment and diffusion. The present invention relates to a substrate processing apparatus such as a diffusion apparatus and a method of manufacturing a semiconductor device using the same.

[0002]

2. Description of the Related Art In an IC manufacturing method, a batch type vertical hot wall type low pressure CVD apparatus is widely used for depositing a CVD film such as silicon nitride or polysilicon on a wafer. A batch-type vertical hot-wall type low pressure CVD apparatus (hereinafter referred to as a CVD apparatus) includes a vertically arranged process tube composed of an inner tube forming a processing chamber into which a wafer is loaded and an outer tube surrounding the inner tube. , A gas introduction pipe for introducing the raw material gas into the inner tube, an exhaust pipe for exhausting the inside of the process tube, and a heater laid outside the process tube for heating the inside of the process tube are provided. The boat is vertically aligned and held by the boat, and is carried into the inner tube through the furnace opening at the lower end. The raw material gas is introduced into the inner tube through the gas introduction pipe, and the inside of the process tube is heated by the heater. Thus, the CVD film is deposited on the wafer. .

In an IC manufacturing method using such a CVD apparatus, processing conditions between batches are controlled in order to suppress variations in film formation between processing operations (hereinafter referred to as batches). It is generally practiced to control the same. For example, when the number of wafers to be processed in one batch (hereinafter, referred to as product wafers) is reduced, the number of product wafers not to be used as products (hereinafter, referred to as dummy wafers) is replaced with the reduced number of product wafers. By replenishing, the processing conditions of the batch whose number has decreased are controlled to be the same as the processing conditions of the batch when the number of sheets does not decrease.

[0004]

However, in the method of manufacturing an IC for replenishing dummy wafers, there is a problem that the manufacturing cost increases by the amount of the dummy wafers.

Therefore, if film formation is performed on the product wafers in a batch that is still insufficient without supplementing the dummy wafers, empty spaces corresponding to the reduced number of wafers are formed in the inner tube processing chamber, so The film formation rate (thickness of the CVD film formed per unit time) changes with respect to the batch film formation rate when the number of wafers to be processed does not decrease. There is a problem that the film thickness of the film varies.

An object of the present invention is to provide a substrate processing apparatus and a semiconductor device manufacturing method capable of preventing the occurrence of variations in processing results while suppressing an increase in manufacturing cost.

[0007]

SUMMARY OF THE INVENTION A substrate processing apparatus for solving the above problems includes a process tube for batch processing a plurality of substrates and a plurality of substrates transferred from a carrier accommodating the substrates. In a substrate processing apparatus comprising a boat and a heater for heating the plurality of substrates held in the boat inside the process tube, the heater includes a plurality of substrates held in the boat, It is characterized in that the plurality of substrates are zone-divided so as to control the heating in correspondence with the stored carrier.

According to a method of manufacturing a semiconductor device for solving the above-mentioned problems, a plurality of substrates transferred from a carrier accommodating the substrates are held inside a process tube by a boat, and the boat is held inside the process tube. A method of manufacturing a semiconductor device, wherein the plurality of substrates held by the substrate are heated by a heater divided into zones so as to control heating for each of the carriers containing the plurality of substrates, When processing a number of substrates less than the maximum number that can be held in the boat, set the division zone of the heater corresponding to the region where the small number of substrates in the boat exists as a soaking zone, It is characterized in that the other divided zones other than the above are set as heat retention zones.

According to the above-mentioned means, when processing a number of substrates less than the maximum number which can be held in the boat,
By setting only the area of the substrate group to be processed as the soaking zone and setting the other areas as the heat retaining zone, the reaction in the heat retaining zone is suppressed and the influence of the reaction in the soaking zone which is the processing area is prevented. Therefore, even if an empty space is formed inside the process tube, the substrate group to be processed existing in the soaking zone is hardly affected by the processing result. As a result, even in a batch in which the number of substrates to be processed is reduced, it is possible to obtain the same processing result as in a normal batch in which the number of substrates is not decreased.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

In the present embodiment, the method for manufacturing a semiconductor device according to the present invention is configured as an IC manufacturing method, and the method for manufacturing an IC according to this embodiment incorporates an IC as a characteristic step. A film forming step of forming, for example, silicon nitride on a wafer as a substrate is provided. The film forming step which is a characteristic step in the IC manufacturing method according to the present embodiment is performed by the CVD apparatus (batch type vertical hot wall type) shown in FIG. 1 which is an embodiment of the substrate processing apparatus according to the present invention. Low pressure CVD apparatus). First, the CVD apparatus shown in FIG. 1 will be described.

As shown in FIG. 1, the CVD apparatus comprises a vertical process tube 1 which is vertically arranged and fixedly supported so that a center line thereof is vertical. The process tube 1 is composed of an inner tube 2 and an outer tube 3, the inner tube 2 is made of silicon carbide (SiC) and is integrally formed into a cylindrical shape, and the outer tube 3 is made of quartz glass and formed into a cylindrical shape. Is integrally molded into. The inner tube 2 is formed in a cylindrical shape with its upper and lower ends open, and the inner hollow portion of the inner tube 2 is substantially a processing chamber 4 into which a plurality of wafers held in a vertically aligned state by a boat are loaded. Is formed in the same way. The lower end opening of the inner tube 2 substantially constitutes a furnace port 5 for loading and unloading a wafer as a substrate to be processed. Therefore, the inner diameter of the inner tube 2 is set to be larger than the maximum outer diameter of the wafer to be handled.

The outer tube 3 is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the inner tube 2 and an upper end closed and a lower end opened, and the inner tube 2 is concentrically covered so as to surround the outer side thereof. . A lower end portion 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 an inner tube for exchanging the inner tube 2 and the outer tube 3. Two
And the outer tube 3 are detachably attached. Since the manifold 6 is supported by the machine frame 18 of the CVD apparatus, the process tube 1 is vertically installed.

An exhaust pipe 7 is provided above the side wall of the manifold 6.
Is connected, and the exhaust pipe 7 is connected to a high vacuum exhaust device (not shown) so that the processing chamber 4 can be exhausted to a predetermined vacuum degree. The exhaust pipe 7 is in a state of communicating with a gap formed between the inner tube 2 and the outer tube 3, and the gap between the inner tube 2 and the outer tube 3 causes the exhaust passage 8 to have a constant cross-sectional shape with a constant width. It has a circular ring shape. Since the exhaust pipe 7 is connected to the manifold 6, the exhaust pipe 7 forms a cylindrical hollow body and is arranged at the lowermost end of the vertically extending exhaust passage 8.

A gas introduction pipe 9 is connected to the lower portion of the side wall of the manifold 6 so as to communicate with the furnace opening 5 of the inner tube 2. The gas introduction pipe 9 is connected to a raw material gas supply device and a carrier gas supply device (whichever is used). (Not shown) as well. The gas introduced into the furnace port 5 by the gas introduction pipe 9 flows through the inside of the processing chamber 4 of the inner tube 2, passes through the exhaust passage 8, and is exhausted by the exhaust pipe 7. Further, a pressure gauge 10 is connected to another portion of the lower portion of the side wall of the manifold 6 so as to communicate with the furnace port 5 of the inner tube 2, and the pressure gauge 10 is located in the upstream side region of the processing chamber 4 of the inner tube 2. Is configured to measure the pressure of the.

A seal cap 17 for closing the lower end opening is abutted on the manifold 6 from the lower side in the vertical direction. The seal cap 17 is formed in a disk shape substantially equal to the outer diameter of the outer tube 3, and is configured to be vertically moved by an elevator (not shown) installed vertically outside the process tube 1. There is. A boat 11 for holding a wafer W as a substrate to be processed is vertically erected and supported on the center line of the seal cap 17.

The boat 11 has a pair of upper and lower end plates 12 and 13 and a plurality of boats vertically erected between the upper end plate 12 and the lower end plate 13 (in the present embodiment, in the present embodiment). 3 holding members 14), and a large number of holding grooves 15 are formed in the three holding members 14 at equal intervals in the longitudinal direction so as to face each other and open. ing. By inserting the wafers W into the holding grooves 15 of the three holding members 14, the boat 11 holds a plurality of wafers W horizontally and aligned with the centers thereof aligned. .

In the present embodiment, the boat 11 is set so as to be able to hold a maximum of 172 wafers W for one batch. That is, the holding grooves 15 of 172 steps are arranged on the three holding members 14 of the boat 11.

A heat insulating cap portion 16 is arranged between the boat 11 and the seal cap 17, and the heat insulating cap portion 16 supports the boat 11 in a state of being lifted from the upper surface of the seal cap 17 to support the boat 11 The lower end is configured to be separated from the position of the furnace opening 5 by an appropriate distance.

A heater 20 for heating the inside of the process tube 1 is provided outside the outer tube 3.
Are installed in concentric circles so as to surround the periphery of the heater, and the outside of the heater 20 is covered with a heat insulating cover 19. The heater 20 and the heat insulating cover 19 are vertically installed by being supported by the machine frame 18 of the CVD apparatus. The heaters 20 are arranged in order from the top, and the first-stage heater section 2
1, second stage heater unit 22, third stage heater unit 23, fourth stage heater unit 24, fifth stage heater unit 25, sixth stage heater unit 2
It is divided into seven parts into six and the seventh-stage heater part 27, and the first-stage heater part 21 to the seventh-stage heater part 27 are configured to be controlled in cooperation with each other and independently by a controller (not shown). There is.

The number N of zone divisions of the heater 20 is N = C
It is set to +2. Here, C is the number of carriers (open cassettes or pods) used in one batch of the process tube 1, and is “5” in the case of the present embodiment. “2” means the heat-retaining zones set at the upper end and the lower end of the process tube 1, respectively, and in the present embodiment, the first-stage heater section 21 and the seventh-stage heater section 27 respectively configure these. is doing. Therefore, the second-stage heater unit 22, the third-stage heater unit 23, the fourth-stage heater unit 24, the fifth-stage heater unit 25, and the sixth-stage heater unit 26 are provided in each of the wafer groups housed in the five carriers. Correspondingly, the length of the heater portion of each stage is set to a length such that the number of wafers for one carrier in the boat 11 is aligned. That is, the heater units 22, 23, 24, 25, and 26 in each stage are zone-divided so as to control heating corresponding to a carrier in which a plurality of wafers are stored.

Next, a batch of the film forming process by the CVD apparatus having the above-mentioned structure in the method for manufacturing an IC according to the present embodiment is performed once to form a CVD film of silicon nitride (Si ₃ N ₄ ) on a wafer. The case will be described.

As shown in FIG. 1, the boat 11 in which a plurality of wafers W are aligned and held is placed on the seal cap 17 with the direction in which the wafers W are lined up being vertical, and the boat 11 is moved by the elevator. It is raised and carried into the processing chamber 4 from the furnace opening 5 of the inner tube 2, and is kept in the processing chamber 4 while being supported by the seal cap 17. In this state, the seal cap 17 seals the furnace opening 5.

The inside of the process tube 1 is exhausted to a predetermined vacuum degree (several tens of Pa or less) by the exhaust pipe 7. At this time, the pressure inside the process tube 1 is measured by the pressure gauge 10, and the degree of vacuum is feedback-controlled. Further, the inside of the process tube 1 is heated to a predetermined temperature (for example, about 760 ° C.) by the heater 20.

Next, the raw material gas 30 as a processing gas is supplied to the processing chamber 4 of the inner tube 2 through the gas introduction pipe 9. When depositing a CVD film of Si ₃ N _4, the raw material gas 30 is SiH ₂ Cl ₂ and NH ₃
Alternatively, SiH ₄ and NH ₃ are introduced into the processing chamber 4.

The introduced source gas 30 rises in the processing chamber 4 of the inner tube 2 and is opened from the upper end opening.
And the outer tube 3 form a gap between the outer tube 3 and the outer tube 3. The raw material gas 30 comes into contact with the surface of the wafer W when passing through the processing chamber 4. Due to the CVD reaction of the raw material gas 30 due to this contact, a CVD film of Si ₃ N ₄ is deposited (deposited) on the surface of the wafer W.

After a preset processing time for depositing the Si ₃ N ₄ CVD film by a desired deposition film thickness, the seal cap 17 is lowered to open the furnace port 5 and to open the boat 11. Wafer W held
The group is carried out of the furnace tube 5 to the outside of the process tube 1.

In the meantime, with the progress of technological innovations such as IT (information technology), there is a demand for the development of an IC manufacturing method which can be used for high-mix low-volume production. In the film forming process in the IC manufacturing method capable of coping with small lot production of many kinds, the number of product wafers in one lot often does not reach the number of product wafers in one batch of the CVD apparatus. Explaining in a specific example, the number of product wafers in one batch in a normal CVD apparatus is 15
On the other hand, the number of product wafers in one lot itself may be, for example, 50 to 75 when performing the film forming process in high-mix low-volume production.

In the method of manufacturing an IC under mass production,
In the configuration of one lot, the number of product wafers (150) in one batch in the CVD apparatus can be taken into consideration. However, in the IC manufacturing method that can be used for small-volume production, the number of product wafers in one lot itself is less than the number of ordinary batches in a CVD apparatus, so that the product in an ordinary batch is CVD with a number (for example, 50 to 75) significantly reduced from the number of wafers (150)
The film-forming process by the apparatus must be carried out.

The number of sheets reduced in this way (50 to 75 sheets)
When the deposition process is performed on the batch of product wafers by the CVD apparatus by using the CVD device, the dummy wafers are replenished in order to match the reduced film formation conditions with the normal number (150) of film formation conditions. Since the number of wafers is large (75 to 100), the cost of the dummy wafer has a great influence on the manufacturing cost of the IC for small-volume production.

Therefore, when only the reduced number of product wafers are held in the boat without refilling the dummy wafers and the film forming process is performed by the CVD apparatus, empty spaces corresponding to the reduced number of wafers are left in the inner tube processing chamber. It was found by the present inventor that the desired precision of the film formation cannot be obtained because of the following reason.

In the spatial reaction model for Si ₃ N ₄ shown in FIG. 2, when there is no silicon wafer in the empty space corresponding to the reduced number of wafers and the gas reaction of η ₀ decreases, SiH ₂ Cl ₂ decomposes to SiCl ₂
The reaction of ₁ will proceed. Here, as shown in FIG. 2, the adsorption coefficient of SiCl ₂ is greater than that of SiH ₂ Cl ₂
Since it is an order of magnitude larger than the above, the reaction of η ₀ is hindered by the absence of a silicon wafer when the empty space with the reduced number of wafers is formed, and the reaction speed increases. That is, the empty space corresponding to the reduced number of wafers is formed in the inner tube processing chamber, so that the ratio of the total surface area of the product wafers in the processing chamber to the volume increases, and the product of the CVD reaction in the empty space becomes the product. Since the area to be transferred to the surface reaction to the wafer is small, the film thickness of the plurality of product wafers in the upper region of the product wafer group held in the boat becomes large.

Further, the exhaust conductance is changed by forming empty spaces corresponding to the reduced number of wafers in the inner tube processing chamber, so that the film formation speed on the wafers is not reduced when the number of wafers to be processed does not decrease. It changes with respect to the batch deposition rate. Further, a CVD reaction occurs in a place where the number of wafers is insufficient, or the consumption amount of the raw material gas is reduced, so that the partial pressure of the raw material gas or the like is changed and the film forming rate is changed.

FIG. 3 is a graph showing the relationship between the position of the wafer on the boat and the film thickness for investigating the relationship between the number of wafers in one batch and the film formation rate.

In FIG. 3, the broken line A shows the case where the number of wafers is about 170, and the broken line B shows the case where the number of wafers is about 13.
The case where the number of wafers is 0 is shown, and the broken line C shows the case where the number of wafers is about 90. The position of the wafer on the boat is taken on the horizontal axis, and the left end indicates the bottom of the boat, that is, the upstream end of the processing gas, and the right end indicates the top of the boat, that is, the downstream end of the processing gas. The vertical axis is the film thickness (Å)
Is taken, and the film thickness correlates with the film formation rate. For example,
The film thickness of the 50th wafer from the bottom of broken line A is about 64
The film thickness of the 50th wafer from the bottom of the broken line B is about 650Å, and the film thickness of the 50th wafer from the bottom of the broken line C is about 658Å.

The processing conditions for film formation are the same in all cases and are as follows. The heating temperature of the heater 20 is 795.0 ° C. for the first-stage heater unit 21, 780.0 ° C. for the second-stage heater unit 22 and the third-stage heater unit 23, and the fourth-stage heater unit 2
4, the fifth-stage heater section 25 and the sixth-stage heater section 26 are
65.0 ° C, and the temperature of the seventh heater section 27 is 750.0 ° C. The source gas and flow rate are 70 sc for SiH ₂ Cl ₂ .
cm (standard cubic centimeter per minute), NH ₃
Is 350 sccm. The pressure is 15 Pa. The pitch of the holding groove of the boat is 5.2 mm.

From FIG. 3, it is understood that the film thickness in the case of the polygonal line A is substantially constant from the upstream side to the downstream side regardless of the position of the wafer on the boat. Since the broken line A corresponds to the case of a normal single batch in which about 170 wafers are held in the boat, the film thickness in the normal single batch is substantially constant over the entire wafer regardless of the position of the wafer. It has been proved that

On the other hand, in the case of the polygonal line B where the number of wafers is about 130, it is understood that the film thickness increases sharply downstream from the bottom to the 88th wafer.
Further, in the case of the polygonal line C where the number of wafers is about 90, it is understood that the film thickness increases sharply downstream from the bottom to the 50th wafer.

The reason why the film formation rate of the wafers held in the upstream region of the boat is stable even in the state where an empty space without wafers is formed in the downstream region of the boat is as follows. Be considered. Since the wafers held in the upstream region of the boat immediately consume the source gas supplied to the processing chamber, even if an empty space without wafers is formed on the downstream side of the processing chamber, the upstream region ( Hereinafter, the film forming speed depending on the consumption of the raw material gas of the wafer arranged in the film forming speed stable region) is hardly affected.

Based on the above investigation, in the IC manufacturing method according to the present embodiment, the number of wafers is reduced even when the empty space for the reduced number of wafers is formed in the inner tube processing chamber. In order to obtain a deposition rate equivalent to that of a normal batch, as shown in FIG.
When the number of wafers W that is less than the number that can be held in the boat 11 is held in the boat 11, the plurality of wafers W are placed in the processing chamber 4 of the boat 11 in an area upstream of the source gas 30. It is supposed to be packed and held. That is, even if an empty space occurs in the downstream region of the boat 11, the dummy wafer is left unfilled. However, so-called side dummy wafers SW that perform functions other than supplementation such as soaking and rectification of gas flow are arranged at appropriate numbers on the upper and lower ends of both sides of the product wafer W group. For example, 5 or 1 side dummy wafers
About 0 and about 15 are arranged.

A method for arranging wafers in a boat according to the present embodiment is shown in the case where the maximum number of wafers that can be held in the boat is about 150 and 75 product wafers W to be made into products in one batch. 1 will be described. For convenience, the number of wafers shown is not the same as the number described below. In addition, 25 per carrier
It is assumed that one product wafer is stored, and the fourth heater section 24, the fifth heater section 25, and the sixth heater section 26 correspond to 25 wafers, respectively.

The 75 product wafers W are the boat 11
Total of 75 located in the film formation rate stable region from the 11th holding groove 15 to the 85th holding groove 15 counting from the bottom of
The holding grooves 15 of the steps are packed and arranged. In addition, the side dummy wafer SW has the holding grooves 1 at the first to the tenth stages on the bottom.
5 and the holding grooves 15 of the 86th to about 96th steps located in the film formation rate unstable region where the film formation rate rapidly increases.

In the film forming process, the second-stage heater section 22 and the third-stage heater section 23 are controlled in addition to the first-stage heater section 21 and the seventh-stage heater section 27 corresponding to the original upper and lower heat-retaining zones, respectively. The temperature is set to the temperature of the heat retaining zone lower than the predetermined processing temperature, and the control temperatures of the fourth-stage heater section 24, the fifth-stage heater section 25, and the sixth-stage heater section 26 are set to the predetermined processing temperature, that is, the soaking zone. It is set to the constituent temperature. The control temperature of the second-stage heater section 22 and the third-stage heater section 23 is set to a temperature at which the above-mentioned reaction in the empty space can be suppressed.

FIG. 5 shows a case where there are 50 product wafers W to be manufactured in one lot.

In this case, 50 product wafers W are held in a total of 50 stages located in the film formation speed stable region from the 6th stage holding groove 15 to the 55th stage holding groove 15 counted from the bottom of the boat 11. The grooves 15 are packed and arranged. The side dummy wafer SW is the holding groove 1 on the first stage to the fifth stage of the bottom.
5 and the holding grooves 15 of the 56th to about 65th steps located in the film formation rate unstable region where the film formation rate increases rapidly.

In the film forming process, the first-stage heater section 21
In addition to the seventh heater section 27, the second heater section 2
2. The control temperatures of the third-stage heater section 23 and the fourth-stage heater section 24 are set to the temperature of the heat retention zone, and the control temperatures of the fifth-stage heater section 25 and the sixth-stage heater section 26 are set to the temperature of the soaking zone. Is set.

FIG. 6 shows a case where the number of product wafers W is 25. In this case, 25 product wafers W are held in a total of 25 stages located in the deposition rate stable region from the sixth stage holding groove 15 to the 30th stage holding groove 15 counted from the bottom of the boat 11. The grooves 15 are packed and arranged. The side dummy wafers SW are arranged in the bottom first holding grooves 15 to the fifth holding grooves 15 and the 31st to 40th holding grooves 15 located in the film forming rate unstable region where the film forming speed rapidly increases. It During the film forming process, the first-stage heater unit 21
In addition to the seventh heater section 27, the second heater section 2
2, the control temperature of the third-stage heater unit 23, the fourth-stage heater unit 24, and the fifth-stage heater unit 25 is set to the temperature of the heat retaining zone, and only the control temperature of the sixth-stage heater unit 26 is the temperature of the soaking zone. Is set to.

FIG. 7 shows a case where the number of product wafers W is 100. In this case, 100 product wafers W are held in a total of 100 stages located in the deposition rate stable region from the sixth stage holding groove 15 to the 105th stage holding groove 15 counted from the bottom of the boat 11. The grooves 15 are packed and arranged. The side dummy wafers SW are arranged in the bottom first holding grooves 15 to the fifth holding grooves 15 and the 101st to 110th holding grooves 15 located in the film forming rate unstable region where the film forming speed increases rapidly. It In the film forming process, in addition to the first heater section 21 and the seventh heater section 27, the control temperature of the second heater section 22 is set to the temperature of the heat retaining zone, and the third heater section 23 and the fourth heater section are set. The step heater section 24, the fifth step heater section 25, and the sixth step heater section 26 are set to the temperature of the soaking zone.

As described above, the number of product wafers W that the boat 11 can hold is smaller than the number that the boat 11 can hold.
Since the raw material gas 30 is packed and held in the film forming rate stable region on the upstream side, even if an empty space is formed on the downstream side of the raw material gas 30 in the processing chamber 4, the film can be held in the film forming rate stable region. Since the film forming rate of each product wafer W is stable without being affected by the empty space, even in a batch in which the number of product wafers W has decreased, the number of product wafers W does not decrease without supplementing dummy wafers. An equivalent film formation rate can be obtained under the same film formation conditions as described above.

Further, the number (eg, 75 or 5) less than the maximum number (eg, 172) that can be held in the boat.
When processing (0) product wafers, only the area of the wafer group to be processed is set as the soaking zone, and the other areas are set as the heat retention zone, so that the reaction in the heat retention zone is suppressed and Since the influence of the reaction in a certain soaking zone can be prevented, the wafers to be processed that are present in the soaking zone have almost no effect on the processing result even if an empty space is formed inside the process tube. You don't have to. As a result, even in a batch in which the number of product wafers to be processed is reduced, it is possible to obtain a processing result equivalent to that of a normal batch in which the number of product wafers is not reduced.

Further, in this embodiment, the pressure in the processing chamber 4 is measured by the pressure gauge 10 in a region upstream of the deposition rate stable region where the product wafers W are placed, that is, in the vicinity of the furnace port 5. The pressure in the area of the product wafer W group is prevented from changing based on the measurement value of the pressure gauge 10. Therefore, the film forming speed of each product wafer W held in the film forming speed stable region is further stabilized without being affected by the empty space.

FIG. 4 is a graph showing the film forming rate of the wafer at the most upstream position due to the change in the pressure measurement position. Solid line D
Shows the case where the pressure measurement position is near the furnace opening according to the present embodiment, and the broken line E shows the case of the conventional example where the pressure measurement position is the exhaust pipe. In FIG. 4, the horizontal axis represents the number of processed wafers, and the vertical axis represents the relative value of the film formation rate.

As shown in FIG. 4, the film forming rate of the broken line E in the conventional example increases in accordance with the increase in the number of processed wafers. On the other hand, the deposition rate of the solid line D according to the present embodiment is constant and stable regardless of the number of processed wafers. In the present embodiment, the reason why the film formation rate is stable regardless of the number of processed wafers is that the pressure in the upstream region of the source gas 30 in the processing chamber 4, that is, the pressure in the vicinity of the furnace port 5 is measured by the pressure gauge 10. , This pressure gauge 10
By maintaining the pressure near the furnace port 5 constant based on the measured value of 1, the CVD reaction of the source gas 30 with respect to the wafer at the most upstream position is maintained constant without being affected by the empty space. , Considered.

Needless to say, the present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the scope of the invention.

The film forming process is not limited to the process of forming a CVD film of Si ₃ N ₄ , but may be a process of forming another CVD film such as polysilicon or silicon oxide.

The CVD apparatus is not limited to the batch type vertical hot wall type low pressure CVD apparatus, but may be another CVD apparatus such as a horizontal hot wall type low pressure CVD apparatus.

Further, the substrate processing apparatus is not limited to the CVD apparatus, and can be applied not only to oxidation processing and diffusion but also to a diffusion apparatus used for carrier activation after ion implantation and reflow for planarization. it can.

In the above embodiment, the case where the wafer is processed is explained, but the object to be processed may be a photomask, a printed wiring board, a liquid crystal panel, a compact disk, a magnetic disk or the like.

[0059]

According to the present invention, it is possible to prevent the occurrence of variations in processing results while suppressing an increase in manufacturing cost.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a film forming process in a method for manufacturing an IC by a CVD apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a spatial reaction model.

FIG. 3 is a graph showing the relationship between the boat position of the wafer and the film thickness for investigating the relationship between the number of wafers in one batch and the film formation rate.

FIG. 4 is a graph showing a film forming rate of a wafer at a most upstream position according to a change in a pressure measurement position.

FIG. 5 is a front sectional view showing a film forming process of an IC manufacturing method according to a second embodiment of the present invention.

FIG. 6 is a front cross-sectional view showing a film forming step of an IC manufacturing method according to a third embodiment of the present invention.

FIG. 7 is a front sectional view showing a film forming process in a method for manufacturing an IC according to a fourth embodiment of the present invention.

[Explanation of symbols]

W ... Product wafer (substrate), 1 ... Process tube, 2 ... Inner tube, 3 ... Outer tube, 4 ... Processing chamber, 5 ... Furnace port, 6 ... Manifold, 7 ... Exhaust pipe, 8 ...
Exhaust passage, 9 ... Gas introduction pipe, 10 ... Pressure gauge, 11 ... Boat, 12, 13 ... End plate, 14 ... Holding member, 15 ... Holding groove, 16 ... Insulation cap part, 17 ... Seal cap, 1
8 ... Machine frame, 19 ... Insulation cover, 20 ... Heater, 21 ... First stage heater part, 22 ... Second stage heater part, 23 ... Third stage heater part, 24 ... Fourth stage heater part, 25 ... Fifth Stage heater section, 26 ... Sixth stage heater section, 27 ... Seventh stage heater section, 3
0 ... Raw material gas (process gas).

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Claims (3)

[Claims] 1. A process tube for batch processing a plurality of substrates, a boat for holding the plurality of substrates transferred from a carrier accommodating the substrates, and a boat held inside the process tube by the boat. In a substrate processing apparatus including a heater for heating the plurality of substrates, the heater corresponds to the plurality of substrates held in the boat in correspondence with the carrier in which the plurality of substrates are stored. A substrate processing apparatus characterized by being zoned so as to control heating. 2. A plurality of substrates transferred from a carrier containing the substrates are held inside a process tube by a boat, and the plurality of substrates held in the boat inside the process tube are A method of manufacturing a semiconductor device in which a plurality of substrates are stored and heated by a zone-divided heater so as to control heating for each carrier, and the number is smaller than the maximum number that can be held in the boat. When processing the substrate of, the divided zone of the heater corresponding to the area where the small number of the substrate exists in the boat is set as a soaking zone, and the other divided zones are set as heat retention zones. A method of manufacturing a semiconductor device, comprising: 3. The method of manufacturing a semiconductor device according to claim 2, wherein the temperature of the heat retaining zone is set lower than the temperature of the soaking zone.