JP2003282388A - Substrate processor, and semiconductor manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently load or unload a substrate on a seat plate, while using the seat plate, such as a holder and prevents the overall substrate processor from becoming large and complicated. <P>SOLUTION: The substrate processor 1 has a furnace 12 to heat process the wafers W, a resistance heater 121 to heat the wafers W in the furnace 12, and a boat 10 to hold the wafers W loaded on a buffer holder 20 in the furnace 12, in a way of supporting and holding or releasing it. When the wafers W are loaded on the buffer holders 20, the rear sides of the wafers W make surface contact with the buffer holders 20, except their peripheries. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device including a semiconductor device and the like, and a substrate processing apparatus used for carrying out the method.

[0002]

2. Description of the Related Art In manufacturing a semiconductor device, there is a step of forming an oxide film, diffusing a dopant, and other heat treatment on a wafer. In recent years, vertical heat treatment chambers are often used for heat treatment of wafers. As a so-called boat loaded in this vertical heat treatment chamber, FIG.
As illustrated in (a), 3 is installed upright in the vertical direction.
In general, a plurality of (or four) columns 201 are formed with a plurality of supporting portions 201a at a predetermined pitch (interval).

As shown in FIG. 11B, this boat 200 supports the wafer W at three points (or four points) by three (or four) sets of supporting portions 201a formed at the same height. Therefore, it was intended to hold it stably and horizontally. However, in this type of boat, since the wafer is point-supported, the load applied to each support point is large,
There has been a problem that a crystal defect called a slip easily occurs near the supporting point of the wafer during the heat treatment.

The mechanism of slip generation is considered as follows. That is, when a wafer at room temperature is inserted into a processing chamber heated to an initial temperature of 500 ° C. to 700 ° C., a temperature difference occurs between the peripheral portion and the central portion of the wafer, so that the wafer is elastically deformed. During the process of deformation, the wafer and the supporting portion of the boat come into contact with each other, but since the boat is made of silicon carbide or quartz having a hardness higher than that of the wafer, scratches occur at the abutting portion of the wafer. Since the self-weight of the wafer is applied to the scratched portion, dislocations are generated from the scratch during the subsequent temperature rising process or constant temperature heat treatment, and a slip occurs on the wafer. Further, when the slip line grows, the wafer finally warps.

When the wafer slips or warps, the flatness of the wafer deteriorates. Then, for example, in the subsequent process, when the resist film applied on the wafer is exposed, the focus shifts in the exposure apparatus, and a problem that a pattern with a predetermined accuracy cannot be transferred occurs.

As a solution to this problem, for example, as disclosed in Japanese Patent Laid-Open No. 9-199438, there is proposed a technique of using a holder having a ring shape in plan view. In this technique, a plurality of ring holders are provided on the support of the boat at a predetermined pitch, and a wafer can be placed on each of these ring holders. Since the weight of the wafer can be distributed to the ring holders, Compared with a three-point (or four-point) support type boat, it was possible to reduce wafer warpage and slip to some extent.

[0007]

On the other hand, when the seat plate such as the ring holder is used as described above, it is necessary to attach and detach the wafer to and from the seat plate, and therefore, there is a problem that the number of steps is increased. is there. Further, in the technique described in the above publication, when transferring the wafer to the boat, it is necessary to separately use a push-up mechanism that passes through all the ring holders in the boat, which makes the entire device complicated and large. There are also challenges. Further, there has been a demand for a technique capable of further reducing the slip or warp of the wafer while using a seat plate such as a ring holder.

An object of the present invention is to provide a technique for efficiently attaching and detaching a substrate to and from a seat plate while using the seat plate and preventing the substrate processing apparatus from becoming large and complicated. Another object of the present invention is to provide a technique for further reducing the slippage or warpage of the substrate during heat treatment by using a seat plate.

[0009]

According to a first aspect of the present invention, a processing chamber for processing a substrate, a heating means for heating the substrate in the processing chamber, and a seat plate for the substrate in the processing chamber are provided. A holding device that holds the seat plate mounted thereon is a substrate processing apparatus that detachably supports the seat plate, wherein a projected area obtained by projecting the seat plate in a plane direction is A substrate processing apparatus is provided which is smaller than the area of the flat surface of the substrate and is configured such that the seat plate is in surface or line contact with the back surface of the substrate.

In the first aspect of the present invention, since the projected area obtained by projecting the seat plate in the plane direction is smaller than the area of the flat surface of the substrate, it is possible to efficiently attach and detach the substrate to and from the seat plate. It can be carried out. In addition, since the seat plate is in surface or line contact with the back surface of the substrate, the weight of the substrate is widely dispersed on the seat plate. This prevents the substrate from slipping or warping.

According to a specific aspect of the present invention, in the substrate processing apparatus according to the first aspect, when the substrate is placed on the seat plate, the portion on the back surface of the substrate excluding the peripheral edge is provided. A substrate processing apparatus is provided in which a seat plate is in surface or line contact.

Here, the peripheral edge refers to an area on the back surface of the substrate, which has a width along the edge of the substrate when viewed from the back surface.

In the substrate processing apparatus according to the specific embodiment of the present invention, when the substrate is placed on the seat plate, the seat plate comes into surface or line contact with a portion of the back surface of the substrate other than the peripheral edge. By scooping up the peripheral part of the back side,
The substrate placed on the seat plate can be acquired. On the other hand, the substrate, which is held with the peripheral portion of the back surface being supported, can be directly scooped up using the seat plate. This allows
Since the step of once acquiring the held substrate and placing it on the seat plate in another region can be omitted, the substrate can be efficiently attached to and detached from the seat plate. Further, since the holder supports the seat plate detachably, the seat plate and the substrate can be transferred to the holder at the same time without using a large-scale device such as a push-up mechanism.
As a result, the size and complexity of the entire device are prevented.

According to a more specific aspect of the present invention, in the substrate processing apparatus according to any one of the above aspects, the holder is arranged in the vertical direction with each of the plurality of substrates placed on the seat plate. There is provided a substrate processing apparatus, which is configured to be held in multiple stages and is configured to batch-process a plurality of these substrates at one time.

According to a second aspect of the present invention, in the method of manufacturing a semiconductor device including a heat treatment step of heat treating a substrate, in the heat treatment step, a projected area obtained by projecting in a plane direction is an area of the flat surface of the substrate. A semiconductor device characterized by using a seat plate that is smaller than the above and is formed so as to make a surface or line contact with the back surface of the substrate, and heat-treats the substrate while the substrate is supported by the seat plate. A method is also provided.

According to a specific aspect of the present invention, in the method of manufacturing a semiconductor device according to the second aspect, in the heat treatment step, the seat plate is in surface or line contact with a portion of the back surface of the substrate other than the peripheral edge. A method for manufacturing a semiconductor device is provided, which comprises supporting the substrate in a state.

According to a more specific aspect of the present invention, in the manufacturing method according to any of the above aspects, the heat treatment is a batch treatment for collectively heat-treating the plurality of substrates. A method of manufacturing the same is provided.

Here, it is preferable that the seat plate is formed in a circular shape in a plan view. Further, it is preferable that the seat plate is formed in a ring shape in a plan view. Further, in these cases, it is preferable that the seat plate is formed such that the outer diameter thereof is approximately ⅔ of the outer diameter of the substrate formed in a substantially circular shape in plan view.

According to another aspect of the present invention, in a method of manufacturing a semiconductor device including a step of heat-treating a substrate formed in a substantially circular shape in a plan view, the centripetal force is applied from an edge of the substrate during the heat treatment. There is also provided a method of manufacturing a semiconductor device, which holds the substrate by supporting a portion spaced apart by a distance corresponding to approximately 1/3 of the radius of the substrate in the direction.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a substrate processing apparatus according to an embodiment. This substrate processing apparatus 1
Is a vertical batch type apparatus used for manufacturing a semiconductor device, and its main part is housed in a housing 2. Case 2
Is provided with a loading unit for loading a wafer W as a substrate, and the pod stage 3 is arranged in the loading unit.

That is, in the substrate processing apparatus 1, the wafer W is loaded by using the wafer pod P1 (see FIG. 9). The required number of wafers W are stored in the wafer pod P1.
Can be stored. Here, the number of wafers W that can be accommodated in the wafer pod P1 is 25, and they are stored in the wafer pod P1 while being arranged in multiple stages. In addition, a buffer jig 20 (see FIG. 3) as a seat plate can be put in the substrate processing apparatus 1. The buffer jig 20 is loaded into the buffer jig pod P2 (see FIG. 8).
Using. The required number of buffer jigs 20 can also be stored in the buffer jig pod P2, and they are stored in the buffer jig pod P2 arranged in multiple stages. still,
These pods P1 and P2 are provided with lids, and when the pods P1 and P2 are put into the substrate processing apparatus 1, they are set on the pod stage 3 with the lids closed.

A pod carrying device 4 is arranged at a position facing the pod stage 3 in the housing 2.
Further, in the vicinity of the pod transfer device 4, the wafer pod P
1 detects the number of wafers W stored in the pod shelf 5 for storing 1; the pod opener 6 for opening the lid of the wafer pod P1 or the buffer jig pod P2; and the wafer pod P1 opened by the pod opener 6. The detector 7 and the like are arranged.

The pod transfer device 4 includes a pod stage 3,
The wafer pod P1 is transferred between the three members, the pod shelf 5 and the pod opener 6. Specifically, the pod carrier 4 stores the wafer pod P1 set on the pod stage 3 in the pod shelf 5, or the pod shelf 5
The wafer pod P1 stored in the pod opener 6 is set in the pod opener 6.

In the housing 2, a wafer transfer machine 8, a notch aligner 9, a boat 10 as a holder, a processing furnace 1 are provided.
2 and the gas box 13 are also arranged at predetermined positions.

The wafer transfer machine 8 performs operations such as transfer of wafers W among the three members, the pod opener 6, the notch aligner 9, and the boat 10. Specifically, the wafer transfer machine 8 acquires a plurality of wafers W from the wafer pod P1 opened by the pod opener 6 and sets the acquired wafers W in the notch aligner 9 or the notch aligner 9 The plurality of wafers W with aligned notches are obtained by using the buffer jig 20, and the obtained wafer W is transferred to the boat 10 together with the buffer jig 20.

Further, the wafer transfer machine 8 is provided with an arm portion 81, and the arm portion 81 can hold a predetermined number of wafers W or the buffer jig 20 at a time. Here, the number of wafers W or buffer jigs 20 that the arm portion 81 can hold at one time is five.

The notch aligner 9 has a notch aligning portion,
And a transfer mechanism section. The notch alignment portion and the transfer mechanism portion are configured to be relatively displaced in the vertical direction (vertical direction in FIG. 2). Here, only the transfer mechanism is configured to be displaced in the vertical direction.

The notch aligning portion collectively aligns the number of wafers W (here, five) that the arm portion 81 can hold at one time (here, five). Specifically, as shown in FIG. 2 (a), the notch aligning portion is a five-tiered support 91, which is arranged in a stack at predetermined intervals in the vertical direction (vertical direction in FIG. 2).
91, and 5 supported by each support 91, 91.
.. and a notch sensor 93 for detecting the notch of the wafer W set on each turntable 92, 92. A sensor for detecting an orientation flat (orientation flat) may be provided instead of the notch sensor 93. That is, the notch aligning portion may be an orientation flat aligning portion.

In the notch aligning section, each of the turntables 92, 92 ... Is configured to rotate independently by a motor and a control section (not shown), and the notch sensor 93 is used in the process of rotating each turntable 92. When the notch of the wafer W set on the turntable 92 is optically detected and the notch is detected, a control signal for stopping the notch at a predetermined position is output to the control unit. In this way, the notch aligning portion aligns the notches of the wafers W in all five stages. Each turntable 92 has three locking portions 9 arranged in the circumferential direction of the wafer W.
2a, 92b, and 92c, and the peripheral edge of the wafer W is aligned with the three engaging portions 92a and 9c during notch alignment.
It is locked by 2b and 92c.

On the other hand, the transfer mechanism section is constructed to be vertically movable (up and down direction in FIG. 2) by an air cylinder or the like (not shown). Specifically, the transfer mechanism section is arranged so as to surround the turntables 92, 92 ...
It has three columns 94, 94, 94. Each of the columns 94 is provided with five wafer supporting portions 94a ... At equal intervals in the longitudinal direction. Each wafer support 94
“A” supports the peripheral edge of the back surface of the wafer W, and protrudes from the support 94 to a position overlapping the peripheral edge of the wafer W in a plan view projection. In detail, the three sets of wafer supporting portions 94a provided at the same height are arranged so as to support the wafer W substantially horizontally. It should be noted that the wafer supporting portions 94a and the locking portions 92a, 92b and 92c of the turntable 92 do not interfere with each other when the transfer mechanism portion moves up and down.

Here, the buffer jig 20 will be described. As shown in FIG. 3, the buffer jig 20 is composed of a flat plate-like body formed in a circular shape in plan view. The buffer jig 20 is smaller than the flat surface of the wafer W in plan view. That is, the buffer jig 20 is formed such that the projection area obtained by projecting the buffer jig 20 in the plane direction is smaller than the projection area obtained by projecting the wafer W in the plane direction. Specifically, the outer diameter of the buffer jig 20 is the wafer W.
The outer diameter is approximately 2/3. Therefore, when the wafer W is placed concentrically on the buffer jig 20, the buffer jig 20 makes surface contact with a portion of the back surface of the wafer W excluding the peripheral edge.

The edge of the buffer jig 20 is formed so that there is no sharp point. Specifically, the radius R is provided on the edge of the buffer jig 20. The edges of the buffer jig 20 may be chamfered. The buffer jig 20 as described above can be made of, for example, single crystal or polycrystal Si (silicon), SiC (silicon carbide), quartz, or the like.

The boat 10 holds a batch of wafers W on the buffer jig 20 in the processing furnace 12 and holds the wafers W in multiple stages. Like the buffer jig 20, the boat 10 holds a single crystal or a polycrystal. Of Si, SiC, quartz or the like. Specifically, the boat 10 generally has a pair of upper and lower end plates 10 as shown in FIG.
1, 102 and at least three columns 103 that are vertically bridged so as to connect the respective end plates 101, 102,
And 103 and 103. Each of the columns 103 has a buffer jig 2 at a predetermined interval in the longitudinal direction thereof.
A plurality of support portions 103a that support the back surface of 0 are provided.

As shown in FIG. 4B, three columns 10 are provided.
Three sets of supporting portions 103a, 103a, 103a formed at the same height in 3, 103, 103 are arranged so that the buffer jig 20 can be supported horizontally. these
The three sets of support portions 103a, 103a, 103a detachably support the buffer jig 20. That is, in this boat 10, three sets of support portions 103a, 103a, 103
The buffer jig 20 is supported by a, and the buffer jig 2 is
The wafer W is held on the wafer 0.

FIG. 4C is a plan view of a state in which the buffer jig 20 and the wafer W are supported by three sets of supporting portions 103a, 103a, 103a formed at the same height. As shown in the figure, each wafer W is placed on the buffer jig 20 in such a state that the center thereof substantially coincides with the center of the buffer jig 20. Further, as shown in the figure, in the substrate processing apparatus 1, when the wafer W is placed on the buffer jig 20, the wafer W
The buffer jig 20 is in surface contact with a portion of the back surface of the substrate other than the peripheral edge. In addition, in FIG. 4C, reference numeral Wa indicates a peripheral edge on the back surface of the wafer W. The peripheral edge Wa on the back surface of the wafer W is, as shown in FIG.
An area on the back surface of the wafer W, which is an annular area having a width along the edge of the wafer W when viewed from the back surface.

FIG. 5A shows the supporting portion 10 in FIG. 4B.
It is the figure which expanded the circumference of 3a. As shown in the figure, a step 103b as an engaging means that engages with the peripheral edge of the back surface of the buffer jig 20 is formed at the tip of each supporting portion 103a. The depth d of the step 103b is smaller than the thickness a of the buffer jig 20. Therefore, the support portion 10
There is no direct contact between the wafer 3a and the wafer W.

Further, as described above, the buffer jig 20
Since the rounded portion R is formed on the periphery of the wafer W, the wafer W is temporarily caused by heat, and thus the phantom line (two-dot chain line) in FIG.
Even if the wafer W and the rounded portion R come into contact with each other as shown by, the force is dispersed in the rounded portion R, so that the wafer W is not damaged. Further, the contact angle between the wafer W and the rounded portion R can be made constant irrespective of the warp state of the wafer W, so that an extreme force is applied to the wafer W even in the process of changing the warp state of the wafer W. Nothing,
Damage to the wafer W can be avoided. In addition, in FIG. 5B, the degree of warpage of the wafer W is exaggerated. Even if the wafer W is warped during the heat treatment, the wafer W and the support 10
There is no direct contact with 3a.

As shown in FIG. 6, the processing furnace (processing chamber) 12 is provided with a resistance heating heater (heating means) 121 and the inside of this heater 121 to make the temperature of the processing furnace 12 uniform and to prevent contamination. Soaking tube 122 to be reduced and this soaking tube 1
A reaction tube 12 provided inside 22 for processing a wafer W
3 and the wafer W from the gas box 13 into the reaction tube 123
For introducing a gas for processing the gas, a gas exhaust pipe 125 for exhausting the gas, a thermocouple 126 for detecting the temperature of the processing chamber, and a boat 10 on which a plurality of wafers W are mounted.
Seal cap 12 for supporting the furnace and closing the furnace opening
7 and temperature control means (not shown) that controls the resistance heater 121 based on the detection result of the thermocouple 126 and controls the temperature in the processing chamber.

Next, the arm portion 81 of the wafer transfer machine 8 described above will be described in detail. The arm portion 81 includes five stages of arms 811 as shown in FIG.
As a whole, the five buffer jigs 20 and / or the wafer W can be collectively held. FIG. 7A shows a state in which the arm 811 holding the buffer jig 20 and the wafer W is viewed from the plane direction. As shown, the arm portion 81
The buffer jig 20 and the wafer W on each arm 811.
Hold it in place.

Further, FIG. 7B shows a cross section of the arm 811. As shown in the same figure, the arm 811 is formed with upper and lower steps 811b and 811c. The lower step 811b is formed so that the buffer jig 20 can be fitted therein. The step 811b has a function of preventing the buffer jig 20 from being displaced when the arm 811 conveys the buffer jig 20. On the other hand, the upper step 81
1c is formed so that the wafer W can be fitted therein.
The step 811c has a function of preventing the wafer W from being displaced when the arm 811 transfers the wafer W.
That is, each arm 811 can hold and carry only one of the buffer jig 20 and the wafer W,
The buffer jig 20 on which the wafer W is placed can be held and transported. Incidentally, these steps 811b, 811c
It is preferable to form a taper on the portion.

The operation of the substrate processing apparatus 1 will be described below. [Buffer jig stock step] Prior to loading the wafer W, the buffer jig 20 is stocked in the empty boat 10. Stocking of the buffer jig 20 is performed as follows. First, the buffer jig pod P2 is set on the pod stage 3 manually or by a transfer device (not shown).
In addition, as shown in FIG. 8A, a plurality of buffer jigs 20 are stored in the buffer jig pod P2 in a state of being arranged in multiple stages at predetermined intervals.

Then, the cassette loader 4 sets the set buffer jig pod P2 on the pod opener 6. The pod opener 6 opens the lid of the set buffer jig pod P2. Next, the arm 811 of the wafer transfer device 8 is inserted below the buffer jig 20 in the opened buffer jig pod P2 (FIG. 8).
(See (b)). Then, the arm 811 rises (see FIG. 8).
(See (c)). As a result, the buffer jig 20 is acquired by the arm 811 (see FIG. 8D). In addition,
The acquired buffer jig 20 is the step 81 of the arm 81.
Since it fits in 1b, the buffer jig 20 does not shift during transfer or transportation. Then, the wafer transfer machine 8
The buffer jig 20 acquired by the arm 811 is transferred to the empty boat 10.

The above operation is repeated until a predetermined number (for example, 150) of buffer jigs 20 are stocked in the empty boat 10. The buffer jig pod P
It is also possible to manually mount the buffer jig 20 on the empty boat 10 without using 2.

[Wafer Loading Step] When the stocking of the buffer jig 20 is completed, the wafer pod P1 in which a predetermined number of wafers W are stored is set on the pod stage 3 manually or by a transfer device (not shown). It should be noted that, as shown in FIG. 9A, a plurality of wafers W are stored in the wafer pod P1 in a state where they are arranged in multiple stages at predetermined intervals.

Next, the cassette loader 4 stocks the set wafer pods P1 on the pod shelf 5, and at the same time, stocks the wafer pods P on the pod shelf 5.
1 is set in the pod opener 6. Pod opener 6
Opens the lid of the set wafer pod P1. Next, the detector 7 detects the number of wafers W accommodated in the opened wafer pod P1.

Next, the wafer transfer device 8 batches the number of wafers W (here, five) according to the detection result of the detector 7 from the wafer pod P1 set in the pod opener 6. The wafer W
Are transferred to the turntables 92 of the notch aligner 9, respectively. The five wafers W extracted from the wafer pod P1 by the wafer transfer device 8 are fitted into the step 811c formed on the arm 811, so that the wafers W are not displaced during transfer and transfer. Absent.

[Notch Alignment Step] Next, the notch aligner 9 includes the turntable 92 on which the wafer W is mounted.
While rotating, the notch position is detected by the notch sensor 93, the turntable 92 is stopped based on the detected information, and the notch positions of all the wafers W are aligned at the same position. At this time, the wafer support parts 94a of the transfer mechanism part in the notch aligner 9 are standing by below the turntable 92 (see FIG. 2A).

Then, the transfer mechanism of the notch aligner 9 is raised. As a result, the same wafer W is picked up by the three sets of wafer supporting portions 94a, 94a, 94a arranged at the same height. At this time, each wafer W has 3
The wafer supporting portions 94a of the set are lifted in a horizontal state while being supported by the peripheral portion of the back surface thereof (see FIG. 2B).

On the other hand, in the wafer transfer device 8, while the transfer of the wafer W to the turntable 92 ... Is completed and the notch alignment is being performed, the buffer jig 20 stocked in advance from the boat 10 is stocked. Take out 5 sheets and wait in front of the notch aligner 9. Thus, the buffer jig 20 is acquired in parallel with the notch alignment of the wafer W, and as a result, the throughput can be improved.

[Wafer Transfer Process] Next, the wafer transfer machine 8 which was on standby in front of the notch aligner 9 and the wafer W picked up by the supporting portions 94a, 94a, 94a after the completion of the notch alignment and the turn. An arm 811 holding the buffer jig 20 is inserted between the table 92 and the table 92 (see FIG. 2C).

In this state, the transfer mechanism portion of the notch aligner 9 descends. As a result, the respective wafers W picked up by the wafer supporting portions 94a ... Are transferred onto the buffer jig 20 (see FIG. 2D).

Next, the wafer transfer machine 8 has an arm portion 81.
When the notched wafers W are respectively acquired on the five buffer jigs 20 held in, the acquired wafers W are transferred to the boat 10 together with the buffer jigs 20.

[Heat Treatment Step] As described above, when each batch of wafers W is placed on the buffer jig 20 and transferred to the boat 10, the processing furnace 12 is closed. The unillustrated furnace gate valve opens and the boat 1
0 is loaded into the processing furnace 12. Then, the processing gas controlled by the gas box 13 is introduced into the processing furnace 12 via the introduction pipe 124, and each wafer W is, for example, 80
Film formation or heat treatment is performed at 0 ° C. or higher. Examples of the processing gas include N ₂ (nitrogen), Ar (argon), H ₂ (hydrogen), O ₂ (oxygen), and the like.

At this time, since the buffer jig 20 and the wafer W are not in point contact but in line contact or surface contact, the weight of the wafer W is widely and evenly distributed over the flat surface of the buffer jig 20. Thereby, in the heat treatment process,
It is possible to prevent the wafer W from being slipped or warped, and to heat-treat the wafer W at a higher temperature than conventional.

When the heat treatment of the wafer W is completed, the boat 1
0 is unloaded from the processing furnace 12 and the furnace gate valve is closed. The boat 10 carrying the processed wafers W waits at a predetermined position until all the wafers W have cooled.

(In the case of the multi-boat specification) When the substrate processing apparatus 1 is of the so-called multi-boat specification, while the wafer is being processed by using one of the boats, the heat treatment is performed in the same manner as described above. The operations of placing the unprocessed wafers W on the buffer jig 20 and setting them on the other boat are performed in parallel. Further, after one of the boats on which the processed wafer W is mounted is unloaded, the other boat on which the unprocessed wafer W is mounted is loaded into the processing furnace 12 and the wafer W is similarly heat-treated. In this way, in the case of the multi-boat specification device, batch processing can be performed continuously, so that the throughput can be improved.

[Wafer Ejecting Step] Now, after the heat treatment step, when the wafer W is cooled to a predetermined temperature in the waiting boat 10, the wafer transfer machine 8 moves from the boat 10 to
Each of the wafers W is acquired together with the buffer jig 20, and is transferred to the notch aligner 9. Then, the notch aligner 9 acquires the processed wafer W from the buffer jig 20 in the reverse order of the above. That is, the wafer transfer device 8 is configured to operate the buffer jig 2 on which the processed wafer W is placed.
0 is arranged above the wafer supporting portions 94a ...
(See (d)). In this state, the transfer mechanism section of the notch aligner 9 rises. As a result, the processed wafers W placed on the buffer jig 20 are scooped up by the three sets of wafer supporting portions 94a ... (FIG. 2).
(See (c)).

Next, the wafer transfer machine 8 once conveys the held buffer jig 20 to a buffer area such as an empty boat 10. Then, again the support portion 94a ...
The arm 811 is inserted below. In this state, the supporting portions 94a ... As a result, the wafer support 94
The processed wafer W picked up by a ... Is transferred to the arm 811. Next, the wafer transfer device 8 stores the received processed wafer W in the empty wafer pod P1 set in the pod opener 6. The wafer pod P1 in which the processed wafers W are stored is stored in the pod shelf 5 and the pod stage 3 by the pod carrier 4.
And the process is completed.

The processed wafer W need not necessarily be discharged via the notch aligner 9. That is, after the heat treatment step, when the wafer W is cooled to a predetermined temperature in the boat 10 that has been waiting, the wafer transfer machine 8 acquires the five wafers W from the boat 10 together with the buffer jig 20. , Directly to the position of the pod opener 6. At this time, it is assumed that an empty wafer pod P1 is set in the pod opener 6.

Next, the wafer transfer device 8 inserts the arm 811 holding the wafer W and the buffer jig 20 above the claw N in the wafer pod P1 (FIG. 9).
(See (c)). Then, the wafer transfer machine 8 is moved to the arm 811.
Then, only the wafer W is placed on the claw N1 (see FIG. 9B). At this time, the buffer jig 20
Since the outer diameter of is approximately ⅔ of the outer shape of the wafer W,
In the process of lowering the arm 811, the buffer jig 20 and the nail N
The 1 and the 1 do not interfere with each other. Thereafter, the wafer transfer device 8 returns the buffer jig 20 mounted on the arm 811 to the empty boat 10. By repeating the above operation, one batch of processed wafers W is discharged to the wafer pod P1 without passing through the notch aligner 9 and the processing is completed.

According to the substrate processing apparatus 1, the following effects can be obtained. (1) Since the boat 10 detachably supports the buffer jig 20, and the wafer W is attached to and detached from the buffer jig 20 by the notch aligner 9,
It is no longer necessary to separately arrange a push-up mechanism or the like, which was required in the past. As a result, the size and complexity of the entire device are prevented.

(2) Since the wafer W is subjected to the heat treatment while being placed on the buffer jig 20, there is no place where the heat of the wafer W is extremely different. Further, since the weight of the wafer W is dispersed in the buffer jig 20, there is no place where the weight is locally applied. Therefore, even if the wafer W is heat-treated at a relatively high temperature, the occurrence of slip or warp is suppressed. As a result, the yield and quality of manufactured semiconductor devices can be improved.

(3) Since the buffer jig 20 is brought into surface contact with a portion of the back surface of the wafer W excluding the peripheral edge, when the wafer W placed on the buffer jig 20 is discharged to the wafer pod P1, The claw N of the wafer pod P1 supporting the peripheral edge of the back surface of the wafer W and the buffer jig 20 do not interfere with each other. As a result, the wafer can be discharged to the wafer pod P1 without passing through the notch aligner 9, and the number of steps can be reduced accordingly.

(4) Since the wafers W can be collectively attached / detached to / from a plurality of buffer jigs 20 without using the nails or the like which are conventionally required to mount the wafer W on the buffer jigs 20, Wafer W (buffer jig 20)
The pitch can be reduced. As a result, the number of wafers for one batch can be increased, so that the throughput can be improved.

(5) The miniaturization and high performance of wiring are accelerating year by year, and the quality required for the Si substrate and the like are becoming severer year by year. For example, a Si substrate having such characteristics as a defect-free surface and a surface layer portion and a sufficient ability to capture metal impurities can be prepared by treating the Si substrate at a high temperature in a hydrogen or argon atmosphere. Since a large number of substrates can be processed at the same time by using the substrate processing apparatus 1 for this processing, it is possible to provide a high-quality substrate at low cost.

[Second Embodiment] The structure of a substrate processing apparatus according to the second embodiment is the same as that of the first embodiment except that the notch aligner 9 is not provided. In short, this substrate processing apparatus attaches and detaches the wafer W to and from the buffer jig 20 in the wafer pod P1 as a substrate storage container (cassette), and the wafer W is inserted into the buffer jig between the wafer pod P1 and the boat 10. It is characterized in that it is transferred while being placed on the 20. In addition, the notch alignment of the wafer W is performed in advance.

The operation of this substrate processing apparatus is as follows. First, similarly to the above, a predetermined number of buffer jigs 2
After stocking 0 in the empty boat 10, the wafer pod P1 in which a predetermined number of wafers W are stored is set on the pod stage 3. Then, the wafer pod P1 on which the cassette loader 4 is set is stocked on the pod shelf 5, and the wafer pod P1 stocked on the pod shelf 5 is set on the pod opener 6. Then, the wafer pod P1 on which the pod opener 6 is set is opened, and the number of wafers W accommodated in the opened wafer pod P1 is detected by the detector 7.

Next, after the number of wafers W is detected by the detector 7, the wafer transfer machine 8 is operated by the buffer jig 20.
From the boat 10 that holds only the buffer jig 2
Get 0 and wait in front of the pod opener 6.

Next, the wafer transfer machine 8 is operated by the buffer jig 2
The arm 811 holding 0 is inserted below the wafer W in the wafer pod P1 (see FIG. 9B). In this state, the wafer transfer device 8 raises the arm 811 to acquire the unprocessed wafer W on the buffer jig 20 (see FIGS. 9C and 9D). At this time, the outer diameter of the buffer jig 20 is approximately 2 / of the outer shape of the wafer W.
Since the number is 3, the buffer jig 20 and the claw N do not interfere with each other in the process of raising the arm 811. Then, the wafer transfer machine 8 transfers the acquired unprocessed wafer W together with the buffer jig 20 to the empty boat 10.

After that, through the same heat treatment process as described above,
The boat 10 is unloaded from the processing furnace, and the furnace gate valve is closed. Then, the boat 10 loaded with the processed wafers W waits at a predetermined position until all the wafers W have cooled. Next, when the wafer W is cooled to a predetermined temperature in the boat 10 that has been on standby, the transfer machine 8 moves from the boat 10 to the predetermined temperature.
Each of the five wafers W is acquired together with the buffer jig 20 and transferred to the pod opener 6. Then, in the empty wafer pod P1 arranged in the pod opener 6, the wafer W is discharged in the reverse order of the above.

That is, the wafer transfer machine 8 has an arm 811 holding the processed wafer W and the buffer jig 20.
Is inserted above the claw N in the empty wafer pod P1 (see FIG. 9C). In this state, the arm 811 of the transfer machine 8 descends (see FIG. 9B). As a result, the processed wafer W is discharged to the empty wafer pod P1 (see FIG. 9A). Thereafter, the wafer transfer machine 8 returns the buffer jig 20 held by the arm 811 to the empty boat 10. By repeating such an operation, the processed wafers W for one batch are discharged to the wafer pod P1 and the processing is completed.

According to this substrate processing apparatus, the following effects can be obtained. When the wafer W is placed on the buffer jig 20, the buffer jig 20 comes into surface contact or line contact with a portion of the back surface of the wafer W other than the peripheral edge. Therefore, in the wafer pod P1, the claw N is on the back surface of the wafer W. By lowering the arm 811 so as to support the peripheral portion, the wafer W placed on the buffer jig 20 can be discharged.
On the other hand, in the wafer pod P1, the wafer W held with the peripheral portion of the back surface supported by the claw N is held.
Can be directly scooped using the buffer jig 20. In this way, the wafer W can be attached to and detached from the buffer jig 20 using the wafer pod P1. Therefore, the step of temporarily acquiring the wafer W from the wafer pod P1 and mounting it on the buffer jig 20 in another area can be omitted, so that the wafer W can be efficiently attached to and detached from the buffer jig, and the entire apparatus can be made compact. And it can be simple.

[Third Embodiment] In the substrate processing apparatus according to the third embodiment, the seat plate shown in FIG.
Since it is the same as the first or second embodiment except that the flat buffer jig 21 formed in a ring shape in plan view as shown in (c) and (d) is used, a detailed description will be given. Omit it. In short, this ring-shaped buffer jig 21
When the wafer W is placed, the wafer W can be supported at a position separated from the edge of the wafer W in the centripetal direction by a distance corresponding to about 1/3 of the radius of the wafer. .

FIG. 10A shows a buffer jig 21 as an example. A plane S is formed on the entire surface of the buffer jig 21. Therefore, when the wafer W is placed on the buffer jig 21, the buffer jig 21 comes into surface or line contact with the back surface of the wafer W. Further, the radius R is formed at the boundary between the outer side surface and the plane S and the boundary between the inner side surface and the plane S of the buffer jig 21. Therefore, even if the wafer W is warped, the wafer W is not damaged. Note that a taper may be formed instead of the radius R.

The shape of the buffer jig 21 is not particularly limited to the above. Modifications of FIGS. 10 (c) and 10 (d)
Is shown in. Buffer jig 21 shown in FIG.
Is formed so that the plane S is not formed but its cross section is arcuate. The curvature of the radius R in this cross section is not particularly limited. The buffer jig 21 shown in FIG. 10D has a larger curvature in cross section than that in the case of FIG. 10C. When the wafer W is placed on the buffer jig 21 shown in FIGS. 10C and 10D, the buffer jig 21 comes into line contact with the back surface of the wafer W. Further, since these buffer jigs 21 are formed in an arcuate cross section, even if the wafer W warps, it does not damage the wafer W.

Now, FIG. 10 (b) is a view of the wafer W placed concentrically on any one of the buffer jigs 21 as viewed from the plane. In the figure, the shaded portion indicates the buffer jig 21. As shown in the figure, the outer diameter of the buffer jig 21 is equal to the outer diameter of the wafer W so as to come into surface contact or line contact with a portion of the back surface of the wafer W formed in a substantially circular shape in plan view except the peripheral edge Wa. It is formed to be approximately 2/3. Specifically, the buffer jig 21 has an inner diameter slightly smaller than ⅔ of the outer diameter of the wafer W and an outer diameter slightly larger than ⅔ of the outer diameter of the wafer W.

Therefore, when the wafer W is placed concentrically on the buffer jig 21 formed as described above, the radius of the wafer W is approximately 1/1 of the radius toward the centripetal direction from the edge of the wafer W. The portion separated by a distance corresponding to 3 (the shaded portion in FIG. 10) is just supported, but according to the inventors' earnest research, the stress applied to the wafer W at that position is the smallest. It is known to be the position.

According to the present embodiment, not only the effects of the first or second embodiment can be obtained, but also the buffer jig 21 having a ring shape in plan view is used and added to the wafer W during the heat treatment. Since the stress can be minimized, the occurrence of slip or warp can be suppressed more reliably.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to this. For example, the shape and the like of the buffer jig 20 can be appropriately changed in design without departing from the spirit of the present invention, and may be formed in a polygonal shape in plan view, for example. Although the wafer W, which is a semiconductor substrate, has been described as a specific example of the substrate, the substrate also includes a glass substrate. The size of the substrate is not particularly limited, but the present invention is suitable for application to heat treatment of a large substrate having a diameter of 300 mm or more, for example.

Example 1 Fifty silicon wafers were placed concentrically on a flat buffer jig made of silicon and having a circular shape in plan view, and were held in a boat made of silicon carbide in multiple stages. The boat was inserted into a processing furnace heated to an initial temperature of 700 ° C. Here, a silicon wafer having a size of φ300 mm is used, and the outer diameter of the buffer jig is φ200 m, which corresponds to 2/3 of the outer diameter of the silicon wafer.
It was m.

After the boat was inserted into the processing furnace, the temperature inside the processing furnace was heated from 700 ° C. to 1000 ° C. at a heating rate of 20 ° C./min. Continuously, the temperature inside the processing furnace was raised from 1000 ℃ to 2 ℃
Heated to 1200 ° C./min. Continuing, the temperature inside the processing furnace
Once 1200 ° C was reached, this temperature was maintained for 1 hour. Next, the temperature inside the processing furnace is reduced from 1200 ℃ to 1 ℃ at a temperature decrease rate of 2 ℃ / minute
The temperature was lowered to 000 ° C. Continue to raise the temperature in the processing furnace to 1000
The temperature was lowered from 700C to 700 ° C at a cooling rate of 10 ° C / min, and the boat was taken out of the processing furnace. Then, when the back surface of the silicon wafer was measured with an optical microscope, scratches and slips were not observed at all.

Example 2 Fifty quartz substrates were placed concentrically on flat buffer jigs made of silicon and each having a circular shape in plan view, and were held in a boat made of silicon carbide in multiple stages. The boat was inserted into a processing furnace heated to an initial temperature of 700 ° C. Here, as the quartz substrate, φ300m
A buffer jig having a size of m and a thickness of 1 mm was used, and the outer diameter of the buffer jig was φ200 mm, which corresponds to 2/3 of the outer diameter of the quartz substrate.

After the boat was inserted into the processing furnace, the temperature inside the processing furnace was heated from 700 ° C. to 1000 ° C. at a heating rate of 20 ° C./min. Continuously, the temperature inside the processing furnace was raised from 1000 ℃ to 2 ℃
Heated to 1100 ° C./min. Continuing, the temperature inside the processing furnace
When reaching 1100 ° C, this temperature was maintained for 2 hours. Then, the temperature inside the processing furnace was reduced from 1100 ° C to 1 ° C at a temperature decrease rate of 2 ° C / min.
The temperature was lowered to 000 ° C. Continue to raise the temperature in the processing furnace to 1000
The temperature was lowered from 700C to 700 ° C at a cooling rate of 10 ° C / min, and the boat was taken out of the processing furnace. Then, when the back surface of the quartz substrate was measured with an optical microscope, no scratches were observed.

[Comparative Example 1] Fifty silicon wafers were held in multiple stages on a boat made of silicon carbide without using a buffer jig, and the boat was inserted into a processing furnace heated to an initial temperature of 700 ° C. . Here, for the silicon wafer, φ
The one having a size of 300 mm was used.

After inserting the boat into the processing furnace, the temperature inside the processing furnace was heated from 700 ° C. to 1000 ° C. at a temperature rising rate of 20 ° C./min. Continuously, the temperature inside the processing furnace was raised from 1000 ℃ to 2 ℃
Heated to 1200 ° C./min. Continuing, the temperature inside the processing furnace
Once 1200 ° C was reached, this temperature was maintained for 1 hour. Next, the temperature inside the processing furnace is reduced from 1200 ℃ to 1 ℃ at a temperature decrease rate of 2 ℃ / minute
The temperature was lowered to 000 ° C. Continue to raise the temperature in the processing furnace to 1000
The temperature was lowered from 700C to 700 ° C at a cooling rate of 10 ° C / min, and the boat was taken out of the processing furnace. Then, when the back surface of the silicon wafer was measured with an optical microscope, a slip line of 3 to 40 mm was observed.

[Comparative Example 2] Fifty quartz substrates were held in multiple stages on a boat made of silicon carbide without using a buffer jig, and the boat was inserted into a processing furnace heated to an initial temperature of 700 ° C. . Here, the quartz substrate has a diameter of 300 mm and a thickness of 1
The size of mm was used.

After inserting the boat into the processing furnace, the temperature inside the processing furnace was heated from 700 ° C. to 1000 ° C. at a temperature rising rate of 20 ° C./min. Continuously, the temperature inside the processing furnace was raised from 1000 ℃ to 2 ℃
Heated to 1100 ° C./min. Continuing, the temperature inside the processing furnace
When reaching 1100 ° C, this temperature was maintained for 2 hours. Then, the temperature inside the processing furnace was reduced from 1100 ° C to 1 ° C at a temperature decrease rate of 2 ° C / min.
The temperature was lowered to 000 ° C. Continue to raise the temperature in the processing furnace to 1000
The temperature was lowered from 700C to 700 ° C at a cooling rate of 10 ° C / min, and the boat was taken out of the processing furnace. Then, when the back surface of the quartz substrate was measured with an optical microscope, scratches of 100 to 300 μm were observed.

[0088]

According to the present invention, it is possible to efficiently attach / detach a substrate to / from a seat plate while using a seat plate such as a holder and to prevent the substrate processing apparatus from becoming large and complicated. It Further, according to the present invention, it is possible to further reduce the slip or warpage of the substrate during the heat treatment by using the seat plate.

[Brief description of drawings]

FIG. 1 is a diagram showing a substrate processing apparatus according to an embodiment.

FIG. 2 is a diagram for explaining attachment / detachment of a buffer jig and a wafer performed by a notch aligner.

FIG. 3 is a plan view showing a buffer jig.

4A and 4B are views showing a boat, in which FIG. 4A is a schematic cross-sectional view thereof, FIG. 4B is a state in which a buffer jig and a wafer are held by the boat, and FIG. 4C is held by the boat. It is the figure which looked at the buffer jig and the wafer from the plane direction.

FIG. 5 is an enlarged view showing the periphery of an end of a buffer jig in a boat.

FIG. 6 is a schematic sectional view showing a heat treatment furnace.

FIG. 7 is a view showing an arm of the wafer transfer machine, (a).
Shows a plan view thereof, and (b) and (c) show sectional views thereof.

FIG. 8 is a view showing a buffer jig pod.

FIG. 9 is a diagram showing a wafer pod.

FIG. 10 is a plan view showing a buffer jig according to another embodiment.

FIG. 11 is a diagram showing a boat according to a conventional technique.

[Explanation of symbols]

1 Substrate processing equipment 10 Boat (holding tool) 12 Heat treatment furnace (processing room) 20 Buffer jig (seat plate) 121 Resistance heating heater (heating means) W wafer (substrate)

Continued front page    (72) Inventor Sadao Nakajima             3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Stocks             Hitachi Kokusai Electric Co., Ltd. F-term (reference) 5F031 CA02 FA01 FA09 FA11 FA12                       FA15 GA49 GA50 HA64 HA65                       JA34 JA35 JA43 KA13 KA14                       MA28 MA30 MA31 NA10 PA13                       PA18 PA30                 5F046 KA04

Claims (2)

[Claims] 1. A processing chamber for processing a substrate, a heating unit for heating the substrate in the processing chamber, and a holder for holding the substrate on the seat plate in the processing chamber. A substrate processing apparatus in which the holder removably supports the seat plate, wherein a projected area obtained by projecting the seat plate in a plane direction is smaller than an area of the substrate flat surface, and the seat plate Is configured to be in surface or line contact with the back surface of the substrate. 2. A semiconductor device manufacturing method including a heat treatment step of heat treating a substrate, wherein in the heat treatment step, a projected area obtained by projecting in a plane direction is smaller than an area of the flat surface of the substrate, and a back surface of the substrate. A method of manufacturing a semiconductor device, comprising: using a seat plate formed so as to come into surface or line contact with the substrate, and heat-treating the substrate while the substrate is supported by the seat plate.