WO2004001835A1

WO2004001835A1 - Heat treating equipment, and methods of manufacturing substrate and semiconductor device

Info

Publication number: WO2004001835A1
Application number: PCT/JP2003/007723
Authority: WO
Inventors: Sadao Nakashima; Tomoharu Shimada; Kenichi Ishiguro; Akira Morohashi
Original assignee: Hitachi Kokusai Electric Inc.
Priority date: 2002-06-21
Filing date: 2003-06-18
Publication date: 2003-12-31
Also published as: JPWO2004001835A1

Abstract

Heat treating equipment and methods for manufacturing a high quality substrate and a high quality semiconductor device by reducing the occurrence of scratches on a silicon wafer or a quartz substrate during a heat treatment, suppressing the occurrence of slip lines on the silicon wafer, and suppressing the warpage of the silicon wafer, the equipment comprising a substrate support body (30) having a body part (56) formed of a plurality of columns (38), wherein support parts (58) coming into contact with the substrates (68), having curved surfaces projected toward the substrates (68), formed of thin film so as to provide spaces therein, elastically deformed when supporting the substrates (68) to support the substrates (68) on the surfaces thereof and to elastically deform according to the deformations of the substrates (68) are installed on placing parts (60) formed on the body parts (56).

Description

Specification

Heat treatment apparatus, substrate manufacturing method, and semiconductor device manufacturing method

Technical field

The present invention relates to a heat treatment apparatus for heat treating a semiconductor wafer, a glass substrate, and the like, a method for producing a substrate for producing a semiconductor wafer, a glass substrate, and the like, and a method for producing a semiconductor device having a step of heat treating the substrate. Background art

For example, when using a vertical heat treatment furnace to heat-treat a plurality of silicon wafers or quartz substrates (hereinafter simply referred to as substrates when both are included), a substrate support (boat) made of silicon carbide or quartz, etc. Is used. A support portion is provided on the substrate support, and the substrate is supported by the support portion. In this case, if the heat treatment is performed at about 1000 ° C. or more, there is a problem that the substrate is damaged near the supporting portion. Furthermore, the silicon wafer has a problem that a slip line is generated and the silicon wafer is warped. When such scratches or slip lines occur, the flatness of the back surface of the substrate deteriorates.

. For these reasons, mask misalignment (mask misalignment due to defocus or deformation) occurs in the lithographic process, which is one of the important processes in the LSI manufacturing process or LCD manufacturing process, and the LSI or LCD having the desired pattern is not The problem that manufacturing was difficult occurred. Disclosure of the invention --The causes of the conventional problems are considered as follows.

When a substrate support having a plurality of room-temperature silicon wafers inserted into a reaction furnace heated to 600 ° C. to 700 ° C., the silicon wafers supported by the substrate support each contain silicon. A temperature difference occurs between the peripheral portion and the central portion in the wafer (see, for example, Japanese Patent Application Laid-Open No. Hei 5-68694). As a result, the silicon wafer is elastically deformed. During this deformation process, the silicon wafer collides with a substrate support made of silicon carbide having a high hardness or a support of a substrate support made of quartz or silicon having the same hardness, and scratches are generated. Yield stress for dislocation generation is significantly reduced at the site where single-crystal silicon wafers are scratched (see Crystal Engineering and Evaluation Technology Committee 144, 68th Study Group (Kadono, p. 4)). As a result, dislocations are generated from the flaws during the subsequent heating process or high-temperature heat treatment, and further, a slip line grows, and the silicon wafer eventually warps. In addition, flaws occur during the heating process, and subsequent heat treatment causes the silicon wafer to warp in the same process. FIG. 19 shows an example of the scratch 2 and the slip line 3 generated on the silicon wafer 1. 4 indicates a notch.

On the other hand, as a method for reducing the slip line, a method in which the surface is supported by a polished substrate support (a holder having the same size as the substrate) can be considered. In this case, the surface is supported over the entire support surface. There are technical problems such as the need to control the degree of finish, and the increase in the contact area, which increases the amount of metal contamination from the substrate support to the substrate.

Similarly, when a substrate support on which a plurality of quartz substrates are arranged is inserted into a reaction furnace heated to 600 ° C. to 700 ° C., the quartz substrate supported by the substrate support becomes However, a temperature difference occurs between the peripheral portion and the central portion in the quartz substrate, and the quartz substrate is elastically deformed. At this time, the quartz substrate is a silicon carbide substrate support having a high hardness, or a quartz or silicon substrate having the same hardness. Collision occurs at the support of the support, causing damage. FIG. 20 shows an example of a flaw 6 generated on the quartz substrate 5.

The present invention solves the above-mentioned conventional problems, reduces the occurrence of scratches or warpage of a substrate generated during heat treatment, and enables a high-quality substrate or semiconductor device to be manufactured. It aims to provide a method for manufacturing devices.

In order to solve the above-mentioned problems, the present inventors have observed flaws generated by a conventional heat treatment apparatus. As a result, it was found that scratches occurred only on the substrate, and hardly occurred on the support portion of the silicon carbide substrate support. Further, when the scratches were observed in detail with an optical microscope, it was confirmed that the scratches were point-like scratches (small area, usually a size of several / m × several meters or less). This means that the effective contact area of the support portion with the substrate is small, and that a relatively large force per unit area (concentration of static load due to its own weight) is applied to the small contact area of the substrate at the support portion. In the process of elastic deformation, the force is estimated to increase further (dynamic load concentration). Furthermore, the hardness of the substrate support is relatively large (hardness of silicon carbide: about 2500 kgf / mm2, hardness of silicon: 1000 to 1050 kgi / mm2, hardness of quartz: 950 to; LOOO kgf Zmm 2) As a result, it was determined that a flaw was generated in the contact area of the substrate contacting the substrate support.

The present invention has been produced from the above-described observation results. A first feature of the present invention is a heat treatment apparatus for performing heat treatment in a state where at least one substrate is supported on a substrate support, The support is provided in a heat treatment apparatus having a main body and a support in contact with the substrate, and the support is formed of an elastic body having a hollow portion. It is preferable that the inside of the hollow portion is not airtight to the outside. It is preferable that the supporting portion is formed of a thin film. The thickness of this film is 20 It is preferably at least m and at most 500 zm. Further, it is preferable that the supporting portion is configured to be in surface contact with the substrate when supporting the substrate. In this way, in order to make surface contact with the substrate, the supporting portion is formed by projecting a thin film with a curved surface toward the substrate side (for example, a hemispherical shape, a semi-elliptical spherical shape, a tunnel shape, etc., hereinafter referred to as a dome structure). When the substrate is supported, it is preferable that the thin film has elasticity due to the weight of the substrate, and that only the leading end becomes flat. The shape of the hollow portion is not limited as long as a space is formed therein, such as a spherical shape, a hemispherical shape, a semi-elliptical shape, and a tunnel shape. Therefore, the effective contact area for supporting the substrate is increased, the contact is made microscopically over a large area (load distribution), and the surface is deformed according to the back surface shape of the substrate and the elastic deformation during heat treatment. This can prevent the substrate from being damaged.

It is preferable that the component constituting the support portion is selected from silicon carbide, silicon, silicon nitride, quartz or glassy carbon, or a composite thereof. This is because these materials are not easily affected as contaminants in the silicon LSI or LCD manufacturing process.

Preferably, the support is detachable from the substrate support. In this case, it is preferable that at least one contact portion between the main body and the support is provided with a means for facilitating the movement of the support relative to the main body. This means is constituted, for example, by polishing at least one contact portion between the main body and the support.

In the heat treatment apparatus configured as described above, the heat treatment is performed, for example, at a temperature of 100 ° C. or more, and further, a temperature of 135 ° C. or more.

According to a second feature of the present invention, in a heat treatment apparatus for performing heat treatment with at least one substrate supported on a substrate support, the substrate support is movable with respect to the main body and the main body. And a movable body provided on the movable body. And a supporting portion that comes into contact with the substrate, wherein the supporting portion is a heat treatment device that is formed of an elastic body having a hollow portion. The above-described support portion can be directly movable with respect to the substrate support. However, by providing the movable body in this way, it is possible to smoothly cope with elastic deformation during heat treatment of the substrate. The movable body may be slidable or rotatable with respect to the substrate support, or may be freely slidable and rotatable.

If the support portion is made of a simple elastic body such as a plate or a wire, the support cannot cope with the horizontal (horizontal) movement due to the thermal expansion and contraction of the substrate, and the substrate may be damaged. In the case of (1), since the supporting portion is made of a hollow elastic body and is rotatable and slidable, it can absorb a lateral movement of the substrate due to thermal expansion and contraction of the substrate.

The present invention includes a method of manufacturing a substrate using the heat treatment apparatus described above, and a third feature of the present invention is that the method includes a step of loading at least one substrate into a processing chamber and a hollow portion. A method of manufacturing a substrate, comprising: a step of supporting a substrate by a support portion made of an elastic body; a step of performing a heat treatment while the substrate is supported by the support portion; and a step of carrying out the substrate from a processing chamber. is there.

The present invention includes a method of manufacturing a semiconductor device using the above-described heat treatment apparatus. A fourth feature of the present invention is that a step of loading at least one substrate into a processing chamber, A method of manufacturing a semiconductor device, comprising: a step of supporting a substrate by a supporting portion made of an elastic body having the same; a step of performing heat treatment while the substrate is supported by the supporting portion; and a step of carrying out the substrate from a processing chamber. It is in. · Brief description of the drawings

FIG. 1 is a perspective view showing a heat treatment apparatus according to an embodiment of the present invention. FIG. 2 is a sectional view showing a reaction furnace used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a first example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 4 shows a first example of a substrate support used in the heat treatment apparatus according to the embodiment of the present invention, and is a cross-sectional view taken along the line III-III of FIG.

FIG. 5 is a schematic diagram schematically illustrating an operation principle of the support portion used in the heat treatment apparatus according to the embodiment of the present invention, and illustrating an example of an amount of deformation when a silicon carbide plate having a thickness of d1 is bent only by A. is there.

FIG. 6 is a schematic diagram schematically illustrating an operation principle of the support portion used in the heat treatment apparatus according to the embodiment of the present invention, and illustrating an example of a deformation amount when the silicon carbide plate having a thickness of d2 is bent by A. is there.

FIG. 7 shows the film thickness, the radius of contact circle, and the stress value applied to the thin film when a load of 41 gw was applied to the support (radius of curvature 50 mm) used in the heat treatment apparatus according to the embodiment of the present invention. 6 is a graph showing the relationship of.

FIG. 8 shows the film thickness, the radius of contact circle, and the stress value applied to the thin film when a load of 41 gw was applied to the support (radius of curvature 30 mm) used in the heat treatment apparatus according to the embodiment of the present invention. 6 is a graph showing the relationship of.

FIG. 9 is a cross-sectional view showing a deformed state of the support portion with respect to the deformation of the substrate in the first example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 10 is a sectional view showing a second example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 11 shows a second example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention, and is a cross-sectional view taken along the line BB of FIG.

FIG. 12 shows a second example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention. It is a top view which shows the support part in an example.

FIG. 13 shows a supporting portion in a second example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention, and is a cross-sectional view taken along line C-C of FIG.

FIG. 14 is a cross-sectional view showing a third example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 15 shows a third example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention, and is a cross-sectional view taken along line DD of FIG.

FIG. 16 is a perspective view showing a fourth example of the support portion of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 17 is a cross-sectional view taken along the line EE of FIG. 16 showing a fourth example of the support portion of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 18 is a sectional view showing a fifth example of the substrate support used in the heat treatment apparatus according to the embodiment of the present invention.

FIG. 19 is a back view showing a silicon wafer as a result of heat treatment performed by a conventional heat treatment apparatus.

FIG. 20 is a rear view showing a quartz substrate as a result of heat treatment performed by a conventional heat treatment apparatus. BEST MODE FOR CARRYING OUT THE INVENTION

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

FIG. 1 shows a heat treatment apparatus 10 according to an embodiment of the present invention. The heat treatment apparatus 10 is, for example, a vertical type and has a housing 12 in which a main part is arranged. A pod stage 14 is connected to the housing 12, and the pod 16 is transported to the pod stage 14. The pod 16 accommodates, for example, 25 substrates and is set on the pod stage 14 with a lid (not shown) closed. Be dropped.

In the housing 12, a pod transport device 18 is disposed at a position facing the pod stage 14. In the vicinity of the pod transport device 18, a pod shelf 20, a pod holder 22, and a substrate number detector 24 are arranged. The pod transport device 18 transports the pod 16 between the pod stage 14, the pod shelf 20 and the pod beech 22. The pod opener 22 opens the lid of the pod 16, and the number of substrates in the pod 16 with the lid opened is detected by the substrate number detector 24.

Further, in the housing 12, a substrate transfer machine 26, a notch aligner 28, and a substrate support 30 (port) are arranged. The substrate transfer machine 26 has, for example, an arm 32 from which five substrates can be taken out. By moving the arm 32, the pod placed at the position of the pod orbner 22, the notch aligner 28 and The substrate is transported between the substrate supports 30. The notch liner 28 detects the notch or the orientation flat formed on the substrate and aligns the substrate. The substrate support 30 has an upper plate 34 and a lower plate 36, and the upper plate 3 and the lower plate 36 are connected to each other by, for example, three columns 38. For example, seventy-five substrates are supported on the support 38, and are loaded into a reaction furnace 40 described later.

The number of columns 38 is not limited to three, but may be any number as long as the substrate can be supported.

In FIG. 2, a reactor 40 is shown. The reaction furnace 40 has a reaction tube 42 into which the substrate support 30 is inserted. The lower part of the reaction tube 42 is opened to insert the substrate support 30, and this open part is sealed by a seal cap 44. The periphery of the reaction tube 42 is covered with a soaking tube 46, and a heater 48 is arranged around the soaking tube 46. Have been. The thermocouple 50 is arranged between the reaction tube 42 and the soaking tube 46 so that the temperature inside the reaction furnace 40 can be monitored. The reaction tube 42 is connected with an introduction tube 52 for introducing a processing gas and an exhaust tube 54 for exhausting the processing gas.

Next, the operation of the heat treatment apparatus 10 configured as described above will be described. First, when the pod 16 containing a plurality of substrates is set on the pod stage 14, the pod 16 is transported from the pod stage 14 to the pod shelf 20 by the pod transport device 18. Stock at 0. Next, the pod 16 stored in the pod shelf 20 is transported to the pod opener 22 by the pod transport device 18 and set. The lid of the pod 16 is opened by the pod opener 22, and the number of substrates is set. The number of boards contained in the pod 16 is detected by the detector 24.

Next, the substrate is taken out of the pod 16 at the position of the pod holder 22 by the substrate transfer machine 26 and transferred to the notch liner 28. In this notch aligner 28, the notch is detected while rotating the substrate, and a plurality of substrates are aligned at the same position based on the detected information. Next, the substrate is taken out of the notch liner 28 by the substrate transfer machine 26 and transferred to the substrate support 30. When a batch of substrates is transferred to the substrate support 30 in this manner, for example, a substrate loaded with a plurality of substrates in a reaction furnace 40 set at a temperature of about 700 ° C. The support 30 is inserted, and the inside of the reaction tube 42 is sealed with a seal cap 44. Next, the processing gas is introduced from the introduction pipe 52. Processing gases include nitrogen, argon, hydrogen, oxygen and the like. At this time, the substrate is, for example, 100 °. It is heated to a temperature higher than about. Meanwhile, while monitoring the temperature inside the reaction tube 42 with the thermocouple 50, the temperature of the substrate is raised according to a preset temperature raising program. When the heat treatment of the substrate is completed, for example, the temperature in the furnace is lowered to about 700 ° C., and then the substrate support 30 is unloaded from the reaction furnace 40 and supported by the substrate support 30. The substrate support 30 is kept at a predetermined position until all the substrates are cooled. During this time, while monitoring the temperature inside the reaction tube 42 with the thermocouple 50, the temperature of the substrate is lowered according to a preset temperature reduction program. Next, when the substrate of the substrate support 30 in the standby state is cooled down to a predetermined temperature, the substrate is taken out from the substrate support 30 by the substrate transfer device 26, and the empty substrate set in the pod opener 22 is removed. Transport to pod 16 for storage. Next, the pod 16 containing the substrate is transported to the pod shelf 20 by the pod transport device 18 and further transported to the pod stage 14 to complete the process.

Next, the substrate support will be described in detail.

3 and 4, a first example of the substrate support 30 is shown. As described above, the substrate support 30 has a main body 56 composed of, for example, three columns 38 and a mounting portion 60. The component constituting main body portion 56 is silicon carbide, silicon, or quartz. The mounting portion 60 is formed on the main body portion 56 continuously inside the main body portion 56 in the longitudinal direction. The mounting portion 60 is formed of a groove, and has an inner wall 62, an upper wall 64, and a lower wall 66, and the substrate 68 can be freely inserted into the mounting portion 60. ing.

However, the cross-sectional shape of the mounting portion 60 is not limited to a quadrangle, and may be another polygon, a part of a circle or an ellipse.

The support portion 58 is mounted on the lower wall 66 of the mounting portion 60 so as to have a hollow portion, that is, to have a space inside. In this embodiment, the support portion 58 has a thin-film dome structure, for example, a silicon carbide thin film having a thickness of 50 zm, and is formed in an upwardly protruding dome shape (for example, a hemispherical shape). Has been done. The substrate 68 is made of, for example, a silicon wafer having a diameter of 300 mm, A portion near the periphery of the back surface of the substrate 68 comes into contact with the support portion 58, and the substrate 68 is supported by the substrate support 30. The supporting portion 58 elastically deforms according to the shape of the substrate 68 by the weight of the substrate 68, and supports the substrate 68 with a relatively large area. Even during the heat treatment, the supporting portion 58 on which the substrate 68 is placed is elastically deformed, so that it can contact and support the substrate 68 with a certain area against various deformations of the substrate 68. It has become. In this embodiment, the support portion 58 is formed only in the plane of the mounting portion 60, but is not limited to this, and is formed beyond the plane of the mounting portion 60. You can also.

However, the support portion 58 is merely mounted on the mounting portion 60, and the inside, that is, the inside of the hollow portion is not airtightly held to the outside, but communicates with the outside. I have. If the inside of the hollow portion is kept airtight with respect to the outside, the gas inside the hollow portion expands during the heat treatment, and the support portion 58 is deformed or damaged. Therefore, the inside of the hollow portion must not be airtight.

Thus, the supporting portion 58 of the thin film dome structure is formed as follows. First, for example, a carbon fiber is processed into a hemispherical shape to form a carbon mold. Next, CVD coating is performed on the carbon mold to form a coating film on the surface of the mold. The coating film is preferably made of silicon carbide, silicon, silicon nitride, quartz or glassy carbon, or a mixture thereof. Thereafter, the mold 58 is removed from the formed coating film, or the mold is baked, whereby the support portion 58 of the thin film dome structure is manufactured.

Further, it is preferable that the thin film forming the supporting portion 58 has a thickness of 20 or more and 500 or less. If the thickness of the thin film is thinner than 20 Aim, it is difficult to maintain the strength of the supporting portion 58, and there is a possibility that the thin film may be damaged. If the thickness is larger than 500 x m, elasticity cannot be obtained.

Next, the operation principle of the support portion 58 in the above embodiment will be described. Generally, when a solid member is made thin, the amount of macro elastic deformation of the member can be increased with a relatively small force. The above embodiment utilizes this property. Even in the dome structure (hemispherical) thin film in the above embodiment, a silicon carbide film that can increase the amount of deformation and has relatively high hardness is, for example, a silicon wafer. This is the reason why elastic shape change is possible with force of c (self-weight is about 122 gw).

Hereinafter, the mechanism will be briefly described. FIGS. 5 and 6 schematically show examples of deformation amounts in silicon carbide when two silicon carbide plates (thicknesses d 1 and 2 d 1) having different thicknesses are bent by the same size A. It is shown in a typical manner. Plates of length L have the maximum elongation or maximum shrinkage (strain) of the outer and inner surfaces of each plate and of L-AL, L + 2AL, and L-12AL. In Fig. 6, when the maximum strain rate 2 AL ZL exceeds the limit value of the inherent elastic deformation strain rate of the silicon carbide material, the silicon carbide film is plastically deformed, and even if the force F2 is removed, the silicon carbide film remains intact. It will not return to its shape (it may even break). On the other hand, in the case of the silicon carbide film with a thickness of d1 (Fig. 5), the maximum strain rate is as small as ALZL, even when the silicon carbide film with a thickness of 2d1 (Fig. 6) is bent by the same A. If is within the range of elastic deformation, the force F 1 (about 18 of F 2) is removed, and it returns to the original shape. In the case of Fig. 5, even if the amount of deformation is increased from A by further applying a force, the deformation can be within the range of elastic deformation.

Therefore, if the thickness of the silicon carbide thin film having the dome structure (hemispherical shape) used in the above embodiment is reduced, the elastic deformation of the thin film can be achieved even if the macro deformation amount of the support portion 58 is relatively large. It becomes possible. Therefore, with a relatively small force, the supporting contact surface is deformed corresponding to the shape of the wafer or the substrate, and the deformation is possible within the range of elastic deformation, and the substrate comes into contact with the substrate 68 The portion where the support portion 58 actually contacts can be a relatively large surface. The thickness of the support portion 58 is determined by the Young's modulus and Poisson's ratio of silicon carbide, the load applied to the support portion 58, the shape of the support portion 58, and the design of the contact surface area. For example, the supporting portion 58 is made hemispherical, the radius of curvature is 50 mm, and the load applied to one supporting portion 58 is 41 gw (when supporting a silicon wafer having a diameter of 300 mm and a weight of 122 gw, three supporting portions are required. 58 (3 places), and if the radius of the contact area is to be 0.5 mm or more, the simulation results (Fig. 7) show that the film thickness is 100 m to 50 m (50 m). When the thickness is less than m, the bending strength of the silicon carbide film exceeds 1Z10). Therefore, in this case, if the thickness of the support portion 58 is set to, for example, 70 Xm, a support method that satisfies a desired load distribution can be realized. However, assuming the Young's modulus, Poisson's ratio, and bending strength of the silicon carbide film to be 4.9 E11 Pa, 0.24, and 6.0 E8 Pa, respectively, the allowable stress applied to the film is bent. This is the case when the strength is 1/10 or less. When the radius of curvature is 30 mm and the thickness of the support portion 58 is 100 mm, the radius of the contact region can be designed to be about 0.3 mm based on the results shown in FIG. Applicable film thickness range when the shape of the supporting part 58 and the quality of the silicon carbide film to be used are different (the above physical property constants are different), or when the allowable stress value applied to the film is not the bending strength of 1Z10 Is obviously different. Similarly, when a silicon thin film, a silicon nitride thin film, a quartz thin film, or a glassy carbon thin film is used as the support portion 58 or a component supported by a composite thereof is used, the load distribution utilizing elastic deformation is similarly reduced. It is possible. In this case, since the physical property constants described above differ depending on the film type, the applicable film thickness range is different, but the applicable range can be obtained by the same procedure as described above.

FIG. 9 shows a deformed state of the above-described hemispherical support portion 58 in the dome structure. Before the substrate 68 is placed, it is shown in Fig. 9 (a). As described above, the support portion 58 is hemispherical and protrudes from the mounting portion 60. That is, the support portion 58 is formed of an elastic body that is a curved surface when the substrate 68 is not supported. When the substrate 68 is placed, as shown in FIG. 9 (b), during the _b heat treatment in which the supporting portion 58 is elastically deformed corresponding to the substrate shape due to the weight of the substrate 68, For example, when the periphery of the substrate 68 is warped upward, as shown in FIG. 9C, the top portion of the support portion 58 is inclined inward so as to match the rear surface angle of the substrate 68. On the other hand, for example, when the periphery of the substrate 68 is warped downward, as shown in FIG. 9 (d), the top portion of the support portion 58 is inclined outward so as to match the back surface angle of the substrate 68. . Thus, the deformation of the substrate 68 can be absorbed by the elastic deformation of the support portion 58. Note that the support portion 58 is not limited to a hemispherical shape, and may have a dome structure.

FIGS. 10 and 11 show a second example of the substrate support 30. In this second example, the main body portion 56 has a holder 70 mounted on the cutout portion 60 of the support column 38 described above. The holder 70 has a disk shape having a diameter slightly smaller than that of the substrate 68, and is made of silicon carbide, silicon or quartz. The holder 70 has an insertion groove 72 formed therein. When the substrate 68 is transferred to the substrate support 30, the insertion groove 72 is provided at the tip of the arm of the substrate transfer machine described above. The twister to be inserted is inserted.

The support portion 58 is disposed on the upper surface of the holder 70 and is formed in a tunnel shape formed of an arc excluding the insertion groove 72. That is, as shown in FIGS. 12 and 13, the support portion 58 is formed in a semicircular cross section from a thin film, and when the substrate 68 is placed on the support portion 58, the support portion 58 Is elastically deformed by its own weight according to the shape of the substrate, comes into surface contact with the substrate 68, and can be deformed corresponding to the deformation of the substrate 68.

The same parts as those in the first example are given the same reference numerals in the drawings and description thereof is omitted. I do.

FIGS. 14 and 15 show a third example of the substrate support 30. In the third example, there are four columns 38, and a mounting portion 60 is formed so as to connect these four columns 38. In the mounting portion 60, a lower wall 66 is formed in a horseshoe shape, and, for example, five hemispherical support portions 58 are formed on the lower wall 66 at predetermined intervals. The number of the support portions 58 is five in the third example, but is not limited to this. If the number is three or more, the substrate 68 can be stably supported. Also in this third example, the support portion 58 is formed of a thin film, elastically deforms according to the substrate shape by its own weight, makes surface contact with the substrate 68, and deforms in accordance with the deformation of the substrate 68. Is what you do. Note that, as described above, the support portion 58 is not limited to a hemispherical shape. As in the dome structure or the fourth example shown in FIG. 16 and FIG. It can also be a circular tunnel.

The same parts as those in the first or second example are denoted by the same reference numerals in the drawings, and description thereof will be omitted.

In the example described above, the support portion 58 may be formed integrally with the main body portion 56 (the mounting portion 60), or may be configured separately from the main body portion 56. When the support portion 58 is formed integrally with the main body portion 56, there is a possibility that the substrate support 30 can be manufactured at low cost. When the support portion 58 is formed separately from the main body portion 56, the support portion 58 can be detached from the main body portion 5.6 and attached to the main body portion 56, so that the support portion 58 can be easily replaced. Since the configuration of the main body portion 56 may be the same as that of the related art, the conventional substrate support 30 can be used as it is. Further, when the support portion 58 is formed separately from the main body portion 56, the support portion 58 is attached to the main body portion 56 in order to absorb a difference in thermal expansion (expansion and contraction difference) of the substrate 68. And move it. ' Specifically, it is only necessary to facilitate the sliding of the supporting portion 58 with respect to the main body portion 56, and the following methods are available to facilitate the sliding. (1) The surface of the portion on which the support portion 58 of the main body portion 56 is placed is smoothed, for example, by polishing. (2) If the surface of the main body 56 is large, a layer or a plate-like member having a polished surface is provided between the main body 56 and the support 58 (this layer or the plate-like member is made of silicon carbide). , Silicon, silicon nitride, quartz or vitreous carbon or a composite thereof).

FIG. 18 shows a fifth example of the substrate support 30. In the fifth example, a movable body 74 is provided between a main body section 56 (placement section 60) and a support section 58. The movable body 74 is made of silicon carbide, silicon, silicon nitride, quartz or glassy carbon, or a composite thereof, and is formed, for example, in an inverted hemisphere, and is movable with respect to the main body 56, that is, It is mounted on the main body 56 so as to be slidable. The supporting portion 58 has, for example, a dome structure (hemispherical shape) having a space formed therein as in the first example, and is placed so that the substrate 68 comes into contact with the supporting portion 58. For example, when the substrate 68 contracts, the movable body 74 rotates as shown in FIG. 18 (b), or the movable body 74 slides as shown in FIG. 18 (c), The shrinkage of the substrate 68 can be absorbed and the occurrence of scratches or the like on the substrate 68 can be more reliably prevented. In order to improve the sliding of the movable body 74, the measures (1) and (2) described above can be applied to one or both of the main body 56 and the movable body 74. The support part 58 and the movable body 74 may be an integral part or an assembled part.

When silicon carbide or silicon is used for main body 56 and silicon carbide, silicon, silicon nitride, or glassy carbon is used for support 58, the heat treatment temperature is the melting point of silicon. Applicable even when the temperature is raised to near 2 ° C. If the amount of deformation of the substrate 68 is large even if the support portion 58 is provided, the substrate 68 Although there is a possibility of contact with the end of the body 56, the occurrence of scratches can be reduced by rounding the end of the body 56.

Next, examples and comparative examples will be described.

The substrate support 30 used has the structure shown in FIGS. 3 and 4, the main body 56 of the substrate support 30 is made of silicon carbide, and the support 58 is a silicon carbide film formed by a chemical vapor deposition method. To form a hemisphere. This support part 58 has a radius of curvature of 50 mm and a film thickness of 60 m, and three (three places) are arranged. The heat treatment is performed using the heat treatment apparatus shown in FIGS. 1 and 2 under the following conditions. . 75 silicon wafers with a diameter of 300 mm were supported on the substrate support per process, and 100% argon was used as an atmospheric gas, and the silicon wafer was inserted into the reactor at an insertion speed of 10 OmmZ. The temperature in the tube when inserting the substrate support was 700 ° C. Thereafter, the temperature was raised from 700 ° C. to 1200 ° C. The temperature was raised at a rate of 16 ° CZ from 700 ° C. to 1000 ° C. and at a rate of 1.5 ° CZ from 1000 ° C. to 1200 ° C. Then, the temperature was maintained at 1200 ° C. for 1 hour, and thereafter, the temperature was lowered from 1200 ° C. to 700 ° C. The temperature was lowered from 1200 ° C to 1000 ° C at a rate of 1.5 ° C / min, and from 1000 ° C to 700 ° C at a rate of 15 ° CZ. The reason for raising and lowering the temperature in two stages (decreasing the rate of temperature rise and decrease at high temperatures) is that if the temperature is rapidly changed at a high temperature, the temperature does not change uniformly within the substrate surface, causing slip. This is because it causes the occurrence. The temperature at which the substrate support was taken out of the reaction furnace was 700 ° C., and the substrate support was taken out at a rate of 10 Omm / min.

After that, as a result of observation with an optical differential microscope, no scratch was generated on the silicon wafer 1 and no slip line was generated. Also, as a result of measuring the warpage of the silicon wafer 1 with a warp meter, the warpage amount was 10 xm or less, and no change was observed before the heat treatment in which the warpage amount was lOm or less. As is generally performed, the measurement of the warpage was performed by erecting a silicon wafer perpendicular to the optical axis of the laser light, scanning the laser light, and calculating from the light reflected from the silicon wafer. The N number is 10 sheets.

In the comparative example, the same experiment as in the example was performed by using a conventional substrate support except for the support portion 58 in FIGS. 3 and 4 and directly supporting the silicon wafer on the silicon carbide substrate support. did. As shown in Fig. 19, on the back side of the silicon wafer, scratches with a size of 50 to 300 / m, a depth of about 5 m, and a height of about 10 occurred at three places corresponding to the support part did. The wounds generated many slip lines about 4 to 30 mm long. The silicon wafer had a warpage of less than 10 / m before the heat treatment, but a warp of about 60 to 90 m after the heat treatment. The N number is 10 sheets.

In the above-described embodiments and examples, the case where the support portion is mainly hemispherical has been described. However, the present invention is not limited to this, and the support portion may be spherical or semi-elliptical spherical. The shape may be an oval sphere, a column, a disk, a tunnel, or the like. In short, a dome structure having a hollow portion may be used. However, it is preferable that the portion in contact with the substrate is a curved surface.

In the description of the above embodiments and examples, a batch-type heat treatment apparatus for heat-treating a plurality of substrates is used as the heat treatment apparatus. However, the present invention is not limited to this. You may.

The heat treatment apparatus of the present invention can also be applied to a substrate manufacturing process.

An example in which the heat treatment apparatus of the present invention is applied to one step of a manufacturing process of a silicon oxide on silicon (SIMOX) wafer, which is a kind of a silicon on insulator (SOI) wafer, will be described.

First, oxygen ions are ion-implanted into a single crystal silicon wafer by an ion implanter or the like. Thereafter, the wafer into which the oxygen ions have been implanted is subjected to the heat treatment of the above embodiment. Annealing is performed at a high temperature of 1300 to 1400 ° C., for example, 1350 ° C. or more, for example, in an atmosphere of Ar and 〇2 using a processing device. Through these processes, a SIMOX wafer in which the SiO 2 layer is formed inside the wafer (the SiO 2 layer is embedded) is produced.

In addition to the SI MOX wafer, the heat treatment apparatus of the present invention can be applied to one step of a hydrogen anneal wafer manufacturing process. In this case, the wafer is annealed at a high temperature of about 1200 ° C. or more in a hydrogen atmosphere using the heat treatment apparatus of the present invention. This can reduce crystal defects in the wafer surface layer on which ICs (integrated circuits) are made, and can increase the crystal integrity. In addition, it is also possible to apply the heat treatment apparatus of the present invention to one step of a manufacturing process of an epitaxial wafer.

Even in the case where the high-temperature annealing treatment is performed as one of the substrate manufacturing steps as described above, the use of the heat treatment apparatus of the present invention can prevent the occurrence of slip of the substrate.

The heat treatment apparatus of the present invention can also be applied to a semiconductor device manufacturing process.

In particular, heat treatment processes performed at relatively high temperatures, such as wet oxidation, dry oxidation, hydrogen combustion oxidation (pyrogenic oxidation), and thermal oxidation processes such as HC1 oxidation, boron (B), phosphorus (P), arsenic ( It is preferable to apply the method to a thermal diffusion step of diffusing an impurity (dopant) such as As) or antimony (Sb) into a semiconductor thin film.

Even in the case of performing the heat treatment step as one of the steps of manufacturing such a semiconductor device, the use of the heat treatment apparatus of the present invention can prevent the occurrence of slip. Industrial applicability

The present invention provides a heat treatment apparatus that needs to reduce the occurrence of scratches or warpage of a substrate during heat treatment, a method of manufacturing a substrate that needs to manufacture a high-quality substrate, and a method of manufacturing a high-quality semiconductor device. It can be used for the manufacturing method of the semiconductor device that needs it.

Claims

The scope of the claims

1. In a heat treatment apparatus for performing heat treatment with at least one substrate supported on a substrate support, the substrate support includes a main body, and a support provided on the main body and in contact with the substrate. A heat treatment apparatus, wherein the support portion is made of an elastic body having a hollow portion.

2. The heat treatment apparatus according to claim 1, wherein the inside of the hollow portion is not airtight to the outside.

3. The heat treatment apparatus according to claim 1, wherein the supporting portion is configured to make surface contact with the substrate when supporting the substrate.

4. The heat treatment apparatus according to claim 1, wherein the support portion is formed of a thin film.

5. The heat treatment apparatus according to claim 4, wherein the thickness of the thin film is 2

A heat treatment apparatus characterized by having a length of 0 m or more and 500 m or less.

6. The heat treatment apparatus according to claim 1, wherein the surface of the support portion is a curved surface.

7. The heat treatment apparatus according to claim 1, wherein a part of the support portion is deformed from a curved surface to a planar shape when the substrate is supported by the support portion.

8. The heat treatment apparatus according to claim 1, wherein the support portion is provided detachably from the main body portion.

9. The heat treatment apparatus according to claim 8, wherein a means for facilitating movement of the support portion relative to the main body portion is provided in at least one contact portion between the main body portion and the support portion. Heat treatment equipment.

10. The heat treatment apparatus according to claim 9, wherein at least one contact portion between the main body and the support is polished.

11. The heat treatment apparatus according to claim 1, wherein a component of the support portion is silicon carbide, silicon, silicon nitride, quartz, glassy carbon, or a mixture thereof.

12. The heat treatment apparatus according to claim 1, wherein a constituent of the main body is silicon carbide, silicon, or quartz.

13. The heat treatment apparatus according to claim 1, wherein the substrate support is configured to support a plurality of substrates in a substantially horizontal state at a plurality of stages with a gap therebetween.

14. The heat treatment apparatus according to claim 1, wherein the heat treatment is performed at a temperature of 100 ° C. or more.

15. The heat treatment apparatus according to claim 1, wherein the heat treatment is performed at a temperature of 135 ° C. or higher.

16. A heat treatment apparatus for performing heat treatment with at least one substrate supported on a substrate support, the substrate support comprising: a main body; a movable body movable with respect to the main body; A heat treatment apparatus, comprising: a support provided on a movable body, the support being in contact with the substrate; and the support is made of an elastic body having a hollow portion.

17. The heat treatment apparatus according to claim 16, wherein means for facilitating movement of the movable body with respect to the main body is provided at at least one contact portion between the main body and the movable part. Heat treatment

18: The heat treatment apparatus according to claim 16, wherein at least one contact portion between the main body and the movable body is polished. Heat treatment equipment. ,

1 9. A step of loading at least one substrate into the processing chamber, a step of supporting the substrate by a support portion composed of an elastic body having a hollow portion, and a heat treatment in a state where the substrate is supported by the support portion. And a step of unloading the substrate from the processing chamber.

20. A step of loading at least one substrate into the processing chamber, a step of supporting the substrate by a support portion made of an elastic body having a hollow portion, and a heat treatment in a state where the substrate is supported by the support portion. A method of manufacturing a semiconductor device, comprising: a step of carrying out a substrate from a processing chamber.