JP2002324830A - Substrate heat treatment holder, substrate heat treatment apparatus, semiconductor device manufacturing method, substrate heat treatment holder manufacturing method, and substrate heat treatment holder structure determination method - Google Patents

Abstract

(57) Abstract: A substrate heat treatment holder capable of improving the planar accuracy of a support portion for supporting a substrate is provided. A holder for substrate heat treatment that horizontally supports a plurality of substrates while vertically separating them from each other, a silicon wafer support that supports each of the plurality of substrates by surface contact,
And a spacer 2 for defining an interval between the silicon wafer supporting portions 1 in the vertical direction. Since the silicon wafer support 1 and the spacer 2 can be manufactured separately, the planar accuracy of the silicon wafer support 1 and the vertical spacing of the silicon wafer support 1 are determined by the accuracy of the silicon wafer support 1 and the spacer 2 alone. By maintaining the initial accuracy, a highly accurate holder for substrate heat treatment can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holder for substrate heat treatment, a substrate heat treatment apparatus, a method of manufacturing a holder for substrate heat treatment, and a method of determining the structure of the holder for substrate heat treatment, and more particularly, to mounting a substrate such as a semiconductor substrate. It is suitable to be applied to a holder for heat treatment of a substrate to be inserted into a heat treatment apparatus.

[0002]

2. Description of the Related Art A semiconductor device such as a MOS LSI or a bipolar LSI is manufactured through many heat treatment steps such as an oxidation step, a CVD step, and a diffusion step. When a vertical heat treatment apparatus such as a vertical low pressure CVD furnace is used in the heat treatment step, silicon (Si) which is a material of a semiconductor device is used.
The wafer is mounted on a vertical heat treatment boat made of SiC or the like and inserted into a reaction tube of a vertical heat treatment apparatus. This vertical heat treatment boat can mount a large number of silicon wafers at appropriate intervals in the vertical direction while keeping the silicon wafers horizontal.

[0003] The general structure of this vertical heat treatment boat is composed of a circular top plate and a bottom plate serving as a pedestal, and three or more columns connecting them. The column is provided with a plurality of silicon wafer supporting portions at intervals larger than the thickness of the silicon wafer, and may have a plate-like shape, a rod-like shape, or a shape in which a groove is directly cut into the pillar.

A boat for vertical heat treatment on which a silicon wafer is mounted is inserted into a vertical heat treatment apparatus. Then, the vertical heat treatment apparatus is inserted into the furnace, and heat treatment is performed at a temperature of, for example, 1000 ° C. At this time, a temperature control method is devised so that thermal stress transition (slip) does not occur particularly in a heat treatment exceeding 1000 ° C.

The material and shape of the vertical heat treatment boat are 10
One used at a temperature of 00 ° C. to 1050 ° C. or lower is different from one used at a higher temperature (hereinafter, referred to as a high-temperature specification). In a vertical heat treatment boat of high temperature specification, a ceramic boat such as SiC is often used. Regarding the shape of the supporting portion, in the case of a vertical heat treatment boat of a high-temperature specification, a silicon wafer supporting a position of about 2/3 of the radius from the center of the silicon wafer toward the outer periphery at three or more points or minute surfaces, silicon There are a type that supports the entire surface of the plate-like surface whose tip extends from the periphery of the wafer to the position of about the radius 2/3, and a type that supports the periphery of the silicon wafer in a ring shape. Here, a ring-shaped support having high production cost and low productivity is poor in practicality as a vertical heat treatment boat and is used only for research.

[0006] In particular, among the element isolation techniques that are key to miniaturization, the formation of STI is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-205.
As disclosed in JP-A-140-140 and JP-A-10-189708, a heat treatment exceeding 1100 ° C. was essential for defect recovery. Japanese Patent Application Laid-Open No. 2000-133607 describes a method of performing oxidation at 1100 ° C. and annealing at 1150 ° C. in order to recover defects even in an element isolation process of an SOI device.

For example, Japanese Patent Application Laid-Open No. 9-205140 discloses an STI (Shallow Trench Isosol).
In the formation process, annealing of a semiconductor wafer such as silicon and an insulator embedded in the trench is performed at 1100 ° C. to 135 ° C.
Techniques performed at 0 ° C. are shown. In a heat treatment exceeding 1100 ° C., a substrate heat treatment holder (sometimes called a boat) is made of silicon carbide. Particularly, in a holder for substrate heat treatment corresponding to a circular plate-shaped wafer having a diameter of 300 mm, a crystal defect called a slip due to its own weight stress is prevented.
Japanese Unexamined Patent Application Publication No. 6-163440 discloses a wafer support member having a ring-shaped part shown in JP-A-60438, a plurality of arc-shaped wafer support members disclosed in JP-A-6-168903, and JP-A-6-163440. A ring-shaped wafer support member or the like is used as a publicly known device. However, the ring-shaped wafer support member is used only for research purposes, and is not used in factories that manufacture semiconductor devices.

[0008]

The size of a silicon wafer has been increasing with the progress of semiconductor manufacturing technology.
Mainstream 300mm diameter wafer from 200mm diameter wafer
Wafer with a diameter of 450, called super silicon.
mm silicon wafers are also being prototyped.

However, a vertical heat treatment boat corresponding to a silicon wafer having a diameter of 300 mm or more has a diameter of 20 mm.
In a 0 mm silicon wafer, even in a relatively low temperature region where thermal stress transfer (slip) does not occur, slip occurs due to an increase in the weight of the silicon wafer. To prevent this, high-temperature vertical heat treatment boats are used, but large-diameter silicon wafers tend to have an in-plane temperature difference, and silicon wafers are single crystals. Easily bends and slip occurs.

When a vertical heat treatment boat of a high temperature specification of a type supported at three points is used, no slip occurs even if heat treatment is performed on a 300 mm wafer at a temperature of 1000 ° C. for one hour. However, there is a problem that a point-like defect occurs at a contact portion with the support portion in the above. In order to prevent this, it is necessary to disperse the load by supporting it on a plate-shaped surface, but since the silicon wafer is bent due to the temperature difference as described above, the occurrence of point defects can be suppressed. Did not.

On the other hand, in recent years, as a vertical heat treatment apparatus for a silicon wafer having a diameter of 300 mm, an apparatus capable of heating and raising the temperature of a silicon wafer more uniformly has been used. For example, a commercially available vertical diffusion furnace manufactured by Koyo Thermo System Co., Ltd., model name VF-5700, has a heating rate of 50 ° C.
Even when the temperature is raised and lowered at a relatively high speed of not less than 15 ° C./minute and a temperature lowering speed of 15 ° C./minute, it is possible to maintain a uniform temperature distribution in the plane of the silicon wafer, and to raise and lower the temperature in a range from 1100 ° C. to 200 ° C. Is possible. However, the present inventors prepared a vertical heat treatment boat supported on the entire plate-shaped surface using quartz as a material using this apparatus, and performed heat treatment, but also failed to suppress the occurrence of slip. .

For example, as described in Japanese Patent Application Laid-Open No. H11-54447, there is a proposal for a wafer heat treatment holding jig having a structure in which quartz is inexpensive and easy to process than SiC, and has a structure in which slip does not easily occur. However, the present inventors also prototyped a wafer heat treatment holding jig corresponding to a wafer having a diameter of 300 mm with reference to this publication and tested it. No slip occurred up to 1000 ° C. Caliber 300
In annealing in a semiconductor device manufacturing process using a mm wafer, it is necessary that no slip occurs at a minimum of 1100 ° C.

FIG. 43 shows a heat treatment tool prototyped by the present inventors based on the description in JP-A-11-54447. If the wafer is made as shown in the original drawing, there is a problem that the wafer moves after mounting. Therefore, the positioning support 105 for fixing the wafer is provided. Since the holding jig for wafer heat treatment is made of quartz and may be deformed like a via barrel when used at 1100 ° C. for a long period of time, a reinforcing portion 106 for preventing deformation is provided. The upper reinforcement part 106 is alternately left and right is the boat support 103
Is to prevent the same from bending in the same direction. As described above, this structure cannot suppress the occurrence of slip at high temperatures.

Although quartz cannot be used at a temperature as high as SiC, the home page of Tosoh Quartz Co., Ltd., reproduced in FIG. 42 (address http: //nsg.min)
o. no. jp / th. According to the graph of viscosity characteristics shown on the screen of “Data Thermal Characteristics of Quartz Glass” in “http://www.tosoh-quartz.co.jp”, quartz made by electrofusion called HR product by Tosoh Quartz Co., Ltd. has viscosity at 1150 ° C. 1
0 ¹⁴ Poise There is a temperature at which the viscosity at which the viscosity becomes a strain point (4 × 10 ¹⁴ Poise), which is a measure of the practical heat-resistant temperature limit, is 1120 ° C.
１1130 ° C., and thus it was confirmed experimentally and theoretically that the device could withstand use at 1100 ° C. sufficiently. Regarding the distortion point, see “Amorphous Silica Material Handbook” on page 87 of Realize, edited by Hiroshi Kawafuku et al. In the section of the characteristic temperature, it is described as "a temperature at which viscous flow does not occur, below which the strain cannot be removed and the viscosity becomes 13.5 Pa.s".

When a ceramic such as SiC is used as the material of the boat for vertical heat treatment, the processing of the SiC is performed before firing, and although the accuracy at this time is relatively good, shrinkage occurs when firing, so Is degraded,
Accuracy is harder to achieve than when quartz glass is used. For this reason, when manufacturing a vertical heat treatment boat using SiC as a material, it is necessary to prepare a necessary number or more of silicon wafer supporting portions that require particularly high accuracy, and to select a silicon wafer supporting portion conforming to the standard from among them. In this case, if the yield is low, the cost increases. Further, although ceramics such as SiC can withstand high-temperature use for a long time, there is a problem that the cost is several times higher than that of quartz. Also,
Due to miniaturization of design rules, the number of processes having a maximum temperature of about 1100 ° C. is increasing even in semiconductor manufacturing processes. As shown in FIG. 42, the strain point (temperature at which the viscosity becomes 4.0 × 10 ¹³ PaS) is 1100 ° C. depending on the type of quartz.
Because of the above, it is extremely uneconomical to use SiC in such a semiconductor device manufacturing process.

By the way, semiconductor devices are becoming more highly integrated and their circuit widths tend to be smaller. As described above, the diameter of the silicon wafer has been increased as the diameter has been increased, and the diameter of the silicon wafer has reached 300 mm.

However, when the lid is opened to construct a factory for 300 mm wafers, there is no high-temperature heat treatment apparatus for 300 mm wafers. In other words, high-temperature heat treatment equipment had to be developed at the same time as the factory construction. Therefore, the holding jig for the wafer heat treatment used in the high-temperature heat treatment equipment is very expensive because shortly after studying a sufficient structure and materials, the highest priority is to prevent the crystal defects called slip from entering the wafer by the high-temperature heat treatment. ing.

The reason why the diameter of the wafer is increased in the first place is to lower the manufacturing cost of the device and increase the international competitiveness. For example, for a 200 mm wafer, a 300 mm wafer is 2.25 times in terms of area, that is, in a simple calculation, if the number of manufacturing devices is the same and the same material cost is used, the number of chips that can be obtained from one wafer is more than twice. That is, the chip cost is reduced to less than half. The cost of manufacturing equipment, materials and parts corresponding to a wafer having a diameter of 300 mm is increased, and it is not permissible that the difference in chip cost is eliminated as compared with a case where a semiconductor device is manufactured using a wafer having a diameter of 200 mm. From these demands, it is urgently necessary to reduce the manufacturing cost of the wafer heat treatment holding jig.

Specifically, the reason why the cost of the conventional holding jig for heat treating a substrate is high can be considered as follows. Although SiC itself as a material is high, for example, 1100 ° C. described in JP-A-6-260438 shown in FIG.
The holding jig for substrate heat treatment corresponding to the above heat treatment has a structure in which a larger amount of SiC is used than the holding jig for substrate heat treatment before the invention of this publication. In some cases, silicon may be used instead of SiC, but the material cost further increases. In addition, silicon or polysilicon is easily oxidized, and silicon oxide has a disadvantage that the volume increases as compared with silicon, so that the strain increases with use. For this reason, there has been a problem that the running cost is increased due to heavy consumption. Further, SiC is a ceramic, and becomes very hard when fired, and is difficult to process. However, since it shrinks when baked after processing, there has been a problem that the cost is further increased if a material having high processing accuracy is required.

Therefore, Japanese Patent Laid-Open No. 6-2604 shown in FIG.
No. 38, the holding jig for heat treatment is 300 mm in diameter.
The cost was calculated to correspond to (3), but the cost was three to four times as large as that of the conventional wafer heat treatment holding jig shown in FIG. In the holding jig for heat treatment described in JP-A-6-260438, a groove for keeping the support member 5 horizontal is provided in the support 16 as shown in FIG. The grooves need to be precisely flush with each other, and the intervals between the grooves are required to be high in accuracy, so that the time required for the formation is long. The holes in the fixing shaft for fixing the support members must also be accurately drilled in each support member, which raises the demand for such accuracy, but in addition to this, the complexity of assembly is also a factor that increases the cost. It is assumed that it is. Further, there is a holding jig for wafer heat treatment described in Japanese Patent Application Laid-Open No. 2000-150401 having a structure similar to that described above, but it is still expensive.

The present inventors have studied the assembling method for the method of preparing the wafer heat treatment holding jig shown in FIG. In FIG. 44, first, a groove for mounting the wafer support member 101 on the boat support 103 is cut, and these are fixed to the bottom plate 102 by welding. At the time of this welding, it is necessary to ensure that there is no difference in sinking of each column due to the melting of quartz, so that the fixing work time of each boat column 103 must be the same and the amount of flame of the burner must be the same. Therefore, very high skill is required to assemble with high accuracy. After fixing each boat support 103, annealing is performed at 1130 ° C. to remove internal strain generated during welding. Next, the required number of wafer support members 101 prepared in advance are mounted, and the positions of the holes through which the fixed shaft 107 penetrates are matched, and the fixed shaft 107 is passed through. The bottom plate 102 is provided with a recess for fixing the fixed shaft 107.
Here, in consideration of workability, one or two of each boat support 103 and the wafer support member 101 are temporarily fixed by welding, and turned upside down on the top plate 104 to perform welding.
Here, the sink by welding does not have to be so much noticed. Then 1130 again to remove internal distortion during welding.
Anneal at ℃. Unless the appearance of the holding jig for wafer heat treatment is considered, the welding of the temporary fixing does not need to be removed. The above-mentioned operation is much more complicated than a normal holding jig for heat treatment of a wafer, which is completed by erecting a column on a bottom plate, mounting a top plate, annealing and completing the annealing. Since SiC cannot be welded, it is assembled using a screw structure or the like.

Further, as described in, for example, Japanese Patent Application Laid-Open No. 11-8203, a support and a support portion are separately formed to reduce cost by using quartz SiC silicon or the like, Some supports are fitted, but especially in the case of high-temperature specifications, 2 /
If the plate-like support portion is long enough to reach the position of about 3, the flatness of the plurality of plate-like support portions cannot be ensured due to a manufacturing error of the thickness of the fitting portion and a manufacturing error of the support plate. In addition, for the structure to fit the support to the support, the thickness of the support must be slightly thinner than the groove for fitting,
When a heavy substrate such as a 300 mm wafer is placed, the support part is slightly tilted, resulting in rattling and a lack of flatness accuracy. If this method is adopted, a 300 mm wafer will slip even at a temperature of 900 ° C. There was a problem.

As another problem, when determining the structure of the supporting portion so as not to cause slip, it is necessary to actually produce the supporting portion in order to confirm the effects of various ideas. However, if the supporting portion is manufactured based on all the ideas, there is a problem that the cost becomes enormous and the time required for the experiment is lengthened. Also, there was no guarantee that satisfactory results would be obtained even if the effects were confirmed, and confirming the effects involved risks.

On the other hand, the inventors of the present invention
While studying the creation of various holders for substrate heat treatment,
It was noted that the holder shown in FIG. 44 had a structural defect. The wafer is mounted on the substrate heat treatment holder by the automatic transfer machine. At this time, the wafer is transferred into the substrate heat treatment holder while being placed on the transfer arm of the transfer machine. The operation at this time will be described below. First, the wafer is taken out by the transfer arm and moved to the vicinity of the substrate heat treatment holder. Next, the transfer arm on which the wafer is placed passes between the plurality of wafer support members 101 arranged vertically, and moves until the wafer is located at the center of the substrate heat treatment holder. Next, the transfer arm moves downward. Thus, the wafer is automatically placed on the wafer support member 101. Thereafter, the transfer arm is pulled out horizontally. Such a procedure is repeated to mount the wafer.

FIGS. 45, 46 and 47 show a series of explanations when this procedure is applied to a wafer heat treatment holding jig having a structure having a wafer support member as shown in FIG. In this case, the wafer W is placed on the transfer arm 26 as shown in FIG. 45, the transfer arm 26 is moved to the substrate heat treatment holder side, and is moved to above the wafer support member 101 as shown in FIG. When the transfer arm 26 is moved downward as shown in FIG.
6a and the wafer support member 101 interfere with each other. For this reason, there has been a problem that the wafer W cannot be transferred in this procedure. As described in JP-A-6-260438, there is an idea to introduce a push-up machine, but this push-up machine is large, and it is necessary to newly provide a place for mounting. In addition, a new system is required to transport the wafer-holding jig on which the wafer is placed to the equipment after the wafer is mounted on the wafer-holding jig, and the movement requires a considerably long vertical and horizontal movement. Become. For this reason, it is unlikely that the system will be realized promptly not only because of the cost increase but also because of the stability of the system.

Further, a silicon wafer supporting member 101A and a silicon wafer supporting member 101B which are formed into two parts in the same range as the outer periphery of the wafer as shown in FIG.
It is more difficult to manufacture the slab with high planar accuracy than a ring-shaped support member cut out from a single plate. In the case of quartz, it is possible to actually place the wafer on the support member and visually check it so that there is no gap between the wafer and the support member, or check the height with a height gauge and adjust it by thermal processing, but it is possible to make it. However, such a creation method is not realistic. It is almost impossible to achieve accuracy with SiC that shrinks after firing. Further, in the case of SiC, since the impurities contained in the material are larger than that of quartz, the material is further coated with SiC by CVD and then used in a heat treatment apparatus. There is also a problem that the flatness is further deteriorated due to enlargement.

Japanese Patent Laid-Open Publication No. 2000-15041 discloses a method in which a holding jig for heat treatment of a wafer is made assembling type so that each part can be exchanged. In this case, if a ceramic that requires sintering and firing after molding, such as SiC, is selected as a material, the material is reduced after sintering, and thus cannot be used as a holding jig for wafer heat treatment that requires high stacking accuracy. Therefore, the method of producing a large number of components and selecting a component within the standard has a problem that the cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first object of the present invention is to provide a holder for heat-treating a substrate, which can increase the planar accuracy of a supporting portion for supporting a substrate. It is in.

A second object of the present invention is to provide a holder for heat treating a substrate, which can securely hold a support portion and a spacer and can improve the workability of assembly.

It is a third object of the present invention to provide a substrate heat treatment holder which can be manufactured while checking an error at the time of stacking, and can detect and deal with a defect at an early stage.

A fourth object of the present invention is to provide a substrate heat treatment holding apparatus capable of confirming the state accuracy of a state in which a substrate is actually placed on a supporting portion, and finding and coping with a defect in a manufacturing stage. To get the ingredients.

A fifth object is to provide a holder for heat treatment of a substrate which can be manufactured without applying thermal deformation or thermal stress.

A sixth object is to reduce cost by using quartz glass as a main material.

It is a seventh object of the present invention to provide a substrate heat treatment holder suitable for loading and unloading substrates using an automatic transfer device.

An eighth object is to determine the structure of the holder for substrate heat treatment in which the slip of the substrate during the heat treatment is suppressed, at a low cost and in a short period of time.

A ninth object is to manufacture a supporting portion of a substrate while minimizing unnecessary portions of a plate as a material.

A tenth object is to provide a low-cost substrate heat treatment holder having a structure that does not generate a slip even when a large diameter wafer is mounted and subjected to heat treatment, and to use the substrate heat treatment holder. It is an object of the present invention to provide a vertical heat treatment apparatus.

[0038]

A substrate heat treatment holder according to the present invention is a substrate heat treatment holder for supporting a plurality of substrates horizontally separated from each other in a vertical direction, wherein each of the plurality of substrates is surface-mounted. It is provided with a support portion that supports by contact, and a spacer that defines an interval between the support portions in the vertical direction.

In order to hold the support portion and the spacer, a plurality of columns are vertically provided on a pedestal. The support portion includes a contact portion for supporting the substrate by surface contact and the column. An engaging portion to be engaged is formed, an engaging portion to be engaged with the support is formed in the spacer, and the support and the spacer are alternately engaged with the support. It is.

The engaging portion of the support portion is a hole formed so as to penetrate the support portion.

Further, the engaging portion of the support portion has a cutout shape formed in the support portion, and at least a part of the cutout shape is the same as the cross-sectional shape of the support.

The engaging portion of the spacer is a hole formed so as to penetrate the spacer.

Further, the engaging portion of the spacer has a notch shape formed in the spacer, and at least a part of the notch shape is the same as the cross-sectional shape of the column.

In the engaging portion between the spacer and the column, a convex portion is formed on one of the spacer and the column and a concave portion is formed on the other, and the convex portion and the concave portion are formed. Are engaged with each other.

A plurality of the support portions are provided to support one substrate, and the position of the hole of the support portion in the horizontal plane substantially coincides with the position of the center of gravity of the support portion in the horizontal plane. Is what it is.

In addition, a plurality of the support portions are provided to support one substrate, and the position of the center of gravity of the support portion on the horizontal plane is defined by the contact portion and the center of the hole of the support portion. It is located on the opposite side.

Further, the support portion and the spacer are fixed between the nut fixed to the upper end of the support and the pedestal in close contact in the vertical direction.

Further, each of the support portion and the spacer is fixed by thermocompression bonding.

The upper and lower surfaces of the support and the spacer are mirror-finished.

Further, the support portion has a ring shape, and a cutout is formed in the support portion at a position where the transfer means for transferring the substrate is inserted.

Further, the outer shape of the inside of the support portion at a position facing the notch portion is wider than other regions.

Further, on the substrate side of the support portion,
A step is provided along the contact portion.

Further, a plurality of notches are formed in the contact portion.

Further, the outer shape of the plurality of spacers arranged at the same height position is arranged so as to be close to the outer shape of the substrate.

Further, an opening is formed in the support portion in a region other than the engagement portion with the column.

Further, the main material is quartz glass.

Further, a substrate heat treatment apparatus of the present invention includes the above-mentioned substrate heat treatment holder.

Further, in the method of manufacturing a semiconductor device according to the present invention, the substrate is subjected to heat treatment using the above-described holder for substrate heat treatment.

The method for manufacturing a holder for substrate heat treatment according to the present invention is a method for manufacturing a holder for substrate heat treatment for supporting a plurality of substrates horizontally while keeping a plurality of substrates vertically separated from each other. Attaching and fixing a plurality of columns,
A step of alternately inserting a supporting portion for supporting the plurality of substrates and a spacer for defining a vertical interval between the supporting portions with respect to the support, and a step of fixing the supporting portion and the spacer in close contact with each other And

Further, by tightening a nut on the upper end of the column, the support portion and the spacer are fixed in a state of being in close contact with each other.

Further, the method further comprises the step of mirror-finishing the upper surface and the lower surface of each of the support portion and the spacer,
The support section and the spacer are fixed by thermocompression bonding.

Further, welding is not performed in steps other than the step of fixing the support to the pedestal.

A step of welding a plurality of quartz glass plates adjacent to each other before inserting the support portion into the column;
The method further includes a step of polishing the connected quartz glass plate, and a step of forming the supporting portion by extracting the quartz glass plate.

Further, the method for determining the structure of the holder for heat-treating a substrate according to the present invention is a method for determining the structure of the holder for heat-treating a substrate, the method comprising: This is to determine an optimal shape of the support portion.

[0065]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. The present inventors conducted various experiments when conceiving the present invention. The experiment was conducted with a focus on comparison between the vertical heat treatment boat of the present embodiment and a conventional vertical heat treatment boat. First, these experiments will be described first, and then the vertical heat treatment boat of the present embodiment will be described.

FIG. 9 is a schematic perspective view showing a conventional vertical heat treatment boat used in this experiment as a comparative example. FIG.
5, 5 is a top plate, 3 is a boat support, 6 is a bottom plate, 7 is a boat positioning groove, 13 is a silicon wafer support rod, 14
Indicates a silicon wafer contact portion at the tip of the silicon wafer support rod 13.

FIG. 10 is a schematic perspective view showing another conventional vertical heat treatment boat used in this experiment as a comparative example. In FIG. 10, 5 is a top plate, 3 is a boat support,
6 is a bottom plate, 7 is a boat positioning groove, 15 is a boat support 3
And a silicon wafer support unit formed integrally with the silicon wafer support unit.

FIG. 1 is a perspective view showing a vertical heat treatment boat according to the present embodiment. In FIG. 1, 1 is a silicon wafer support, 5 is a top plate, 3 is a boat support, 6 is a bottom plate, 2
Denotes a spacer, and 7 denotes a boat positioning groove. These parts constituting the vertical heat treatment boat shown in FIG. 1 are manufactured using quartz as a main material.

In the experiment, using the respective vertical heat treatment boats shown in FIGS. 9, 10 and 1 and focusing on the silicon wafer support portions 1 and 15 and the silicon wafer support rod 13 of each boat, the structure thereof is shown. -The state of occurrence of slip on the wafer due to the difference in the manufacturing method was examined. In this experiment, a vertical heat treatment apparatus capable of performing heat treatment while suppressing the above-described temperature difference across the wafer was used.

The processing conditions are as follows. Diffusion furnace: High-speed heating / cooling type furnace manufactured by Koyo Thermo System Co., Ltd. Model name VF-5700 sample silicon wafer: 300 mm diameter, P type, connection shaft <100> manufactured by Mitsubishi Materials Corporation
Specific resistance 10-15Ωcm Oxygen concentration 1.1 ± 0.1E
18 / cm ³ Atmosphere: N ₂ atmosphere slip observation: using Rigaku Corporation X-ray topography systems

First, using the boat shown in FIG.
Heat treatment was performed at 000 ° C. for 2 hours, and the slip on the silicon wafer was observed. FIG. 11 shows the result of the slip observation. As shown in FIG. 11, no slip occurred under these conditions, but a point defect called a boat mark by the present inventors occurred at the silicon wafer contact portion 14 at the tip of the silicon wafer support rod 13. You can see that there is. As described above, the wafer mark having a diameter of 300 mm is heavy in its own weight, and a point mark at the silicon wafer contact portion 14 causes a boat mark.

Next, using the boat shown in FIG. 9, the heat treatment conditions were changed and the heat treatment was performed at a temperature of 1050 ° C. for 1 hour, and the slip was observed. FIG. 12 shows the result. As shown in FIG. 12, a slip having a length of about 5 mm has occurred from each boat mark. As in the case of FIG. 11, the concentration of the load is the main cause of the occurrence of the defect. However, it is assumed that the silicon wafer bends at a high temperature in addition to the concentration of the load, causing a slip.

Next, using the boat shown in FIG.
After the heat treatment at 050 ° C. for one hour, the slip on the silicon wafer was observed. FIG. 13 shows the result. The occurrence of slip at a contact portion of the two silicon wafer support portions 15 with a length of 20 mm or more from the periphery of the silicon wafer can be clearly identified without enlargement. Further, in this case, since a point-like defect called a boat mark is not recognized, it can be estimated that the deflection of the silicon wafer has not occurred. After the observation, the silicon wafer was again placed on the silicon wafer support 15 and visually checked, and it was found that the silicon wafer support 15 and the silicon wafer were not in close contact. That is, it has been found that the planar accuracy of the three silicon wafer support portions 15 is not obtained. For this reason, in the boat shown in FIG. 10, the surface accuracy is insufficient even though the silicon wafer is faced, and as a result, line contact or point contact due to the edge of the support portion 15 occurs. It can be seen that slip occurs.

Next, using the boat of this embodiment shown in FIG. 1, a heat treatment was performed at a temperature of 1050 ° C. for one hour, and the surface of the silicon wafer was observed. FIG. 14 shows the result. As shown in FIG. 14, when the boat of the present embodiment was used, neither a boat mark nor a slip was observed.

Based on the above experimental results, the cause of the deterioration of the surface accuracy of the silicon wafer support 15 in the case of the conventional boat shown in FIG. 10 was considered. As a result, it has been found that the surface accuracy of the silicon wafer supporting portion 15 cannot be increased by the current manufacturing technology for the following reasons. In particular,
When quartz was used as the main material, it was found that required accuracy could not be obtained due to factors in the manufacturing process.

The outline of the manufacturing process of the boat shown in FIG. 10 is as follows. 1. The silicon wafer support 15 is cut out from the boat support 3 and the silicon wafer support 15 is polished. Here, shaving is performed by an automatic machine, and at this stage, the boat support 3 with the silicon wafer support 15 can be mass-produced with high accuracy. 2. 3 or more boat supports 3 on bottom 6
At this time, welding with an oxyhydrogen burner. At this time, since the treatment is performed at a temperature at which quartz melts, the boat support 3 sinks on the bottom surface 6. When welding, the boat support 3
Must be held vertically, and the difference in the adjustment time is the difference in the amount of sinking of each boat support 3. 3. The top plate 5 is welded to the upper part, and the silicon wafer support 15
Polish with a burner. The heat treatment at this time may cause deformation of the silicon wafer support 15. 4. Annealing is performed in a furnace to remove distortion. Since the temperature at this time is higher than the strain point of quartz of 1100 ° C. or more, the silicon wafer support 15 is deformed.

As described above, in the boat manufacturing process shown in FIG. 10, there are at least three heat treatment steps in which an error occurs, and this causes a deterioration in the planar accuracy of the silicon wafer support 15. Therefore, in order to use quartz as the material in the present embodiment, it is possible to improve the planar accuracy of the silicon wafer support 15 by reducing the heat treatment as much as possible.

From the above experiments and considerations, the present inventors have come up with the present invention as described in the following embodiments. Hereinafter, the present embodiment will be described in detail with reference to the drawings.

As shown in FIG. 1, a specific example of the substrate heat treatment holder (boat) of the present embodiment is a quartz substrate used for mounting a semiconductor substrate (silicon wafer) and inserting it into a vertical heat treatment furnace as described above. This is a vertical boat for heat treatment.

As shown in FIG. 1, the top plate 5 and the bottom plate 6 of the holder for substrate heat treatment according to the present embodiment are connected via three boat columns 3. Silicon wafer support portions 1 and spacers 2 are alternately penetrated in each of the three boat posts 3. Since the thickness dimensions of the silicon wafer support portion 1 and the spacer 2 are strictly defined, the nth (n is an integer) third from the bottom attached to each boat support 3
The planar accuracy of the upper surface of the one silicon wafer support 1 is kept very high.

Referring to FIGS. 2, 3 and 7, FIG.
The method for producing the vertical heat treatment boat described above will be described. First, a required number of silicon wafer support portions 1 and spacers 2 are prepared.
Then, as shown in FIG.
And the bottom plate 6 and the boat support 3 are fixed by welding. Thereafter, annealing is performed to remove the distortion generated during welding. Next, as shown in FIG.
Through the boat support 3. The spacer 2 is provided with a hole 2a through which the boat support 3 penetrates, and the inside (not shown) of the hole 2a on the lower surface of the spacer 2 is formed by the boat support 3 and the bottom plate 6.
Is chamfered so as not to interfere with the welded portion. Next, the silicon wafer support 1 is passed through the boat support 3. The silicon wafer support 1 is also provided with a hole 1a through which the boat support 3 penetrates. As described above, the necessary number of spacers 2 and silicon wafer supporting portions 1 are alternately passed through the boat support 3, and after passing the last spacer 2, the nut 4 is fastened to the boat support 3 as shown in FIG. 7.

A male screw 16 to which the nut 4 is tightened is formed on the upper part of the boat support 3. Then, FIG.
As shown in FIG. 7, the boat support 3 and the top plate 5 are fixed by passing the tip of the boat support 3 through the support plate fixing hole 8 of the top plate 5 to complete the vertical heat treatment boat. In addition, male screw 16
May be formed only on the upper part of the boat support 3. And
The tightening of the nut 4 eliminates rattling between the silicon wafer support 1 and the spacer.

Since there is no heat treatment step after assembling the silicon wafer support 1 and the spacer 2, the flatness of the three silicon wafer supports 15 supporting the same wafer is equal to that of each silicon wafer support 1 and each spacer 2. It is determined by the accuracy of a single unit. Each component can be mass-produced with an existing machine with high accuracy, and can be selected to obtain a good product, so that a further improvement in accuracy can be achieved. Further, when a defective portion is found by inspection or the like, only the corresponding silicon wafer support portion 1 or spacer 2 can be replaced, and resources can be used effectively. In addition, the above configuration and manufacturing method make it possible to use quartz as the main material of the substrate heat treatment holder, so that the manufacturing cost is reduced to a fraction of that in the case where ceramic such as SiC is used. Can be done.

Next, the center of gravity 11 of the silicon wafer support 1
A method for further improving the planar accuracy of the silicon wafer supporting portion 1 by defining the positional relationship between the silicon wafer supporting portion 1 and the hole 1a will be described. 4 and 5 are schematic diagrams showing the positional relationship between the hole 1a and the center of gravity 1 of the silicon wafer support 1.

As shown in FIG. 4, the silicon wafer support 1
If the center of the hole 1a is aligned with the center of gravity 11, the silicon wafer support 1 is always horizontal at the stage of overlapping, so the surface accuracy of the three silicon wafer supports supporting the same wafer is checked. A boat can be made while doing so.

Further, as shown in FIG. 5, by positioning the center of the hole 1a closer to the side supporting the silicon wafer than the center of gravity 11, the surface accuracy is confirmed in a state where the silicon wafer is actually placed. Silicon wafer support 1
And the spacers 2 can be sequentially stacked. Therefore, if the surface accuracy of the support portion 1 holding the same wafer is poor, it can be replaced with a good product at the stage of stacking.

The shape of the hole 1a of the silicon wafer supporting portion 1 may be adjusted to the shape of the boat support 3;
Is a column, a fixing projection 9 is provided in the hole 1a so that the angular position does not shift as shown in FIGS. 4 and 5, and a fixing groove is formed in a corresponding portion on the boat support 3 side as shown in FIG. 10 are provided. Thus, the rotation of the silicon wafer support 1 around the boat support 3 can be suppressed.

Embodiment 2 The present inventor repeated the above experiment and found that the silicon wafer support 1 and the spacer 2
Have recognized that they may adhere naturally. Hereinafter, a second embodiment in which this phenomenon is actively used will be described.

FIG. 8 shows a manufacturing process of the holder for substrate processing according to the second embodiment. The basic configuration and manufacturing process of the second embodiment are the same as those of the first embodiment. However, in the second embodiment, both surfaces of the silicon wafer supporting portion 1 and the spacer 2 are mirror-finished, and both are thermally compressed. It differs from the first embodiment in that it is fixed.

As shown in FIG. 8, at the stage where the spacer 2 and the silicon wafer support 1 are sequentially passed through the boat support, both surfaces of the silicon wafer support 1 and the spacer 2 are mirror-finished. Have been. If the suction is insufficient at this stage, it is regarded as poor mirror finish and replaced with a non-defective product. In the second embodiment, it is only necessary to place the top plate 5 without using the nut 4, so that it is not necessary to cut the male screw 19 on the upper part of the boat support 3. After placing the top plate, the boat is annealed at a temperature at which the quartz is not deformed, so that the silicon wafer support 1 and the spacer 2 are completely bonded by thermocompression.

The method according to the second embodiment can provide a boat that can withstand practical use. In addition, even if the top plate 5 and the boat support 3 are welded at the upper portion of the top plate before the final annealing, and thereafter annealing is performed, there is no visible shift.

Embodiment 3 When observing the state of occurrence of slip by the X-ray topography system shown in FIG. 13 in detail,
The slip occurs at the positions of the silicon wafer support 15B and the silicon wafer support 15C in the quartz boat cross-sectional view shown in FIG. 15, but does not occur at the position of the silicon wafer support 15A. This can be presumed to be because the silicon wafer supports 15B and 15C in the boat in FIG. 10 are parallel as shown in FIG. However, as shown in FIG.
Radially divide the silicon wafer support portions 1A, 1
When the longitudinal direction of B, 1C is extended, the support portions 1B, 1C
The gap between the boat supports 3 supporting the support becomes narrow, and the silicon wafer W and the boat support 3 come into contact with each other at the time of insertion. Therefore, this structure cannot be adopted.

On the other hand, as shown in FIG. 17, when the length of the silicon wafer support portion 1 is increased and the interval between the boat posts 3 is widened so that the silicon wafer W can be taken in and out, interference with the reaction tube 18 in the vertical heat treatment apparatus occurs. Resulting in. Therefore, this structure cannot be adopted. Reaction tube 1 to avoid interference
If 8 is widened, the clearance between the silicon wafer W and the reaction tube 18 becomes too large, so that uniform film formation cannot be performed. Further, if the silicon wafer supporting portions 1 on the same plane are connected, the silicon wafer W cannot be inserted by a machine, so that it cannot be used in a mass production site.

In the third embodiment, as shown in FIG.
Silicon wafer support 1D and silicon wafer support 1E
Is bent. Thereby, the silicon wafer support portions 1D and 1E can be positioned on the line 19 radially divided into three from the center of the silicon wafer W.

FIGS. 19 to 21 show the silicon wafer support 1 having a shape capable of suppressing the occurrence of slip as in FIG. As described above, many examples of the shape of the silicon wafer supporting portion 1 capable of dispersing the load under the condition that there is no problem with the flatness can be considered, but it is experimentally determined which shape is excellent in economy and anti-slip performance. It is not easy. In the third embodiment, the silicon wafer support portions 1 of the respective shapes and the quartz boat
If it is, the experiment can be performed by attaching the silicon wafer supporting portions 1 of a plurality of shapes at once, so that the optimal structure can be determined with a small number of experiments.

Embodiment 4 Next, a fourth embodiment in which the clearance with the quartz tube in the vertical heat treatment apparatus is reduced will be described. FIG. 22 is a perspective view showing a mating state of the boat support 3 of the holder for substrate heat treatment according to the fourth embodiment with the silicon wafer support 1 and the spacer 2, and FIG. 23 is a boat support 3 and a silicon wafer support. 1 and spacer 2
FIG. As shown in FIG. 23, in the fourth embodiment, the boat support 3 is cut off in a half-moon shape at a position on the opposite side of the silicon wafer support portion 1 from the portion where the silicon wafer contacts, to form a flat portion. A notch is also provided in the silicon wafer support 1 and the spacer 2 which are engaged with the boat support 3.

The position of the flat portion of the boat support 3 is set outside the center of the boat support 3, that is, with respect to the center of the boat support 3, in order to ensure the engagement with the silicon wafer support 1 and the spacer 2. It should be located on the opposite side of the contact area with the wafer. The positions of the notches formed in the silicon wafer supporting portion 1 and the spacer 2 are also the flat portions 3.
It is located outside the center of the boat support 3 in correspondence with the position a.

As described above, by forming the flat portion on the boat support 3 and the cutout portions on the silicon wafer support portion 1 and the spacer 2, it is possible to reduce the maximum diameter of the holder for substrate heat treatment. On the back side of the silicon wafer support 1, the quartz tube of the vertical heat treatment apparatus can be brought closer to the silicon wafer. Thereby, in the holder for substrate heat treatment according to the fourth embodiment, the effect of the first embodiment can be obtained, and the efficiency of heat treatment performed by inserting the holder into the vertical heat treatment apparatus can be further improved. .

In each of the above embodiments, the support 3
Although three are used, four or more may be used.

Although the frequency of occurrence is low, even when the silicon wafer supporting portion is damaged due to carelessness or equipment failure, only the damaged portion can be replaced, so that the repair cost can be reduced. If several pieces are naturally damaged, it is determined that the end of the durability time has come, and it is desirable to replace all the silicon wafer supporting portions.

In the holder for substrate heat treatment of each of the above-described embodiments, each component is made into a component (top plate 5, bottom plate 6,
Boat support 3, silicon wafer support 1, spacer 2
Etc.), each part can be manufactured by an NC machine. Therefore, as compared with the case where the conventional holder for heat treatment of a substrate as shown in FIGS. 9 and 10 is manufactured, manufacturing costs including labor costs can be significantly reduced. In addition, not only can manufacturing cost be reduced by using quartz glass as a main material, but also manufacturing cost can be reduced by forming each component into a component. For example, a material such as SiC is used. Even in the case of the configuration, the manufacturing cost can be reduced as compared with the conventional structure. When a material such as SiC is used, the top plate 5, the bottom plate 6, the boat support 3, and the spacer 2 are made of quartz glass because the silicon wafer support 1 is apt to undergo thermal deformation at high temperatures. Support part 1
Is made of SiC, deformation can be minimized and accuracy can be improved, and cost can be reduced even when SiC is used.

Embodiment 5 FIG. FIG. 24 shows a silicon wafer support 2 used for the holding jig for heat treatment of a substrate according to the fifth embodiment.
0 is a plan view. FIG. 25 is a perspective view of a spacer 21 used in the holding jig for heat treating a substrate according to the fifth embodiment. FIG. 27 is a perspective view of the lowermost spacer 22 used in the lowermost part of the substrate heat treatment holding jig according to the fifth embodiment (FIG. 27).
(A)) and its sectional view (FIG. 27 (b)). Here, FIG. 27B is a dashed line II- shown in FIG.
It shows a cross section along II ′. As shown in FIGS. 27A and 27B, a tapered surface 22b is formed below the lowermost spacer 22.

The lowermost spacer 22 and the spacer 21 are provided with holes 22a, 21a through which the boat support 23 penetrates, respectively. Similarly, the silicon wafer support 20 is provided with a hole 20a through which the boat support 23 penetrates. In these assembling methods, a required number of lowermost spacers 22, spacers 21, and silicon wafer supporting portions 20 are first prepared, and a boat support 23 is erected on a bottom plate 24 of a holder for substrate heat treatment as shown in FIG. First, the lowermost spacer 22 is passed through the tapered surface 22b side downward. The tapered surface 22b is for preventing interference with the swelling of the weld formed when the bottom plate 24 and the boat support 23 are connected. Next, the silicon wafer supporting portion 20 is passed through the boat support 23 and the spacer 21 is passed. Hereinafter, the silicon wafer supporting portions 20 and the spacers 21 are alternately passed. After passing through all the silicon wafer support portions 20 and the spacers 21, the top plate 25 is attached to the uppermost portion, and the holder for substrate heat treatment is completed. FIG. 29 is a perspective view showing the completed holder for substrate heat treatment.

In the fifth embodiment, one silicon wafer support 20 holds one wafer W. For this reason, the silicon wafer 20 has a ring shape having the same size as the outer shape of the wafer W. The transfer arm 2 is provided on a part of the silicon wafer support 20.
A notch is formed to allow the passage of the sixth through.

As shown in FIG. 24, after the wafer W is placed, the contact surface with the wafer W is cut horizontally so that the wafer W does not move to form the silicon wafer contact portion 20b. (I-I 'cross section shown in FIG. 24) Further, an arm avoiding portion 20c is formed at a part near the center inside the silicon wafer supporting portion 20. Thus, FIGS.
7, the interference between the tip 26a of the transfer arm 26 and the silicon wafer support 20 can be suppressed. FIG. 28 shows a transfer arm 26 during transfer of a wafer W.
FIG. 3 is a plan view showing the positional relationship between the silicon wafer supporter 20 and the silicon wafer support 20; In addition, by providing the arm avoiding portion 20c,
Loading and unloading of the wafer W from the holder for substrate heat treatment can be performed using an automatic wafer transfer device.

Here, the spacer 21 is not limited to the ring type shown in FIG. 25, but may be a C type as shown in FIG. FIG. 26A shows a C-type spacer 2.
7 is a perspective view, and FIG. 26B is a top view. The C-shaped spacer 27 has no hole through which the boat support 23 penetrates, but the concave portion 27a serves as a hole. By using the C-shaped spacer 27 to direct the concave portion 27a to the outside of the substrate heat treatment holder, it is possible to prevent the spacer from protruding from the substrate heat treatment holder. This makes it possible to reduce the clearance between the substrate heat treatment holder and the reaction tube. Further, by directing the concave portion 27a toward the inside of the substrate heat treatment holder, the wafer W
And spacer interference can be suppressed.

Further, a convex portion 27b is formed on the C-shaped spacer 27 so as not to separate from the boat support 23, and as shown in FIG.
A concave portion 23a that fits into 7b is formed. When a convex portion is formed on the boat support 23, a concave portion fitted to the convex portion is formed on the spacer 27. Boat props 23 and C
A plurality of convex portions 27b and concave portions 23a may be provided on one spacer 27 and boat support 23 in order to ensure the connection of the mold spacer 27. Thereby, it is possible to prevent the C-shaped spacer 27 from coming off the boat support 23.

As in the above embodiments, the thickness of the spacers 21, 22, 27 is strictly defined. In addition, since the silicon wafer supporting portion 20 is cut out from one plate, its thickness is also strictly defined, and the planar accuracy is determined at the stage of the plate as a material. Therefore, the position and the planar accuracy of the upper surface of the n-th (n is an integer) silicon wafer supporting portion 20 attached to each boat support 23 are maintained with high accuracy, and there is no possibility that a slip occurs during the heat treatment. 1
The holder for substrate heat treatment corresponding to a high-temperature heat treatment exceeding 100 ° C. needs to be made of SiC, but in the case of a spacer made of SiC, the dimensional variation is larger than that of quartz. When precision is required in relation to the automatic transfer machine, the spacers 21, 22, and 27 made of quartz can be used without crushing, for example, up to 1150 ° C. Therefore, it is preferable to use a holder for substrate heat treatment in which only the spacers 21, 22, 27 are made of quartz. However, in this case, the planar accuracy of the SiC silicon wafer support 20 is the same as that of the quartz silicon wafer support 2.
It is slightly inferior to that of 0.

The work requiring skill in the method of manufacturing a holding jig for heat treatment of a substrate according to the fifth embodiment is performed by using a boat support 23.
All that is required is to connect the bottom plate 24 and the top plate 25 and attach the top plate 25 to the upper portion of the boat support 23. Other steps include the silicon wafer support 20 and the spacers 21, 22, 2
Since the layers 7 are merely stacked alternately, manufacturing costs can be reduced. Further, the spacers 21, 22, 27 and the silicon wafer supporting portion 20 can be mass-produced, and the unit price is lower as the number of manufactured products is larger. Therefore, it is possible to obtain a substrate heat treatment holder for high-temperature heat treatment that achieves high dimensional accuracy and low cost.

Embodiment 6 FIG. FIG. 30 is a plan view of a silicon wafer support 20 used as a holder for heat treatment of a substrate according to the sixth embodiment. The basic configuration and manufacturing process of the sixth embodiment are the same as those of the fifth embodiment, but the silicon wafer contact portion 20b of the silicon wafer support portion 20 of the sixth embodiment
Are cut into triangles to reduce the contact area with the wafer W. In FIG. 30, the cuts are formed in an acute angle, but may be U-shaped, semicircular, or rectangular, and a shape that can be easily processed can be adopted. This structure has a particularly high specific heat of quartz glass (0.3 cal / g ·
° C) is effective in preventing heat from escaping around the wafer from escaping.

Embodiment 7 FIG. FIG. 31 shows a silicon wafer support 2 used for the holder for substrate heat treatment according to the seventh embodiment.
0 is a plan view. The basic configuration and manufacturing process of the seventh embodiment are the same as those of the fifth embodiment, but the silicon wafer support 20 of the seventh embodiment is not formed with the hole 20a through which the boat support 23 penetrates. Instead, a portion that interferes with the boat support 23 outside the silicon wafer support 20 is cut out to provide a support engaging portion 20d. This method is adopted when the silicon wafer support 20 cannot be provided with the hole 20a through which the boat support 23 penetrates. In this case, the shapes of the engaging portions 20d arranged at four positions are changed to the spacers 21 and
The silicon wafer support 20 can be held at an appropriate position by matching the outer shape of the silicon wafer support 2 or 27.

Embodiment 8 FIG. FIG. 32 shows a silicon wafer support 2 used for the substrate heat treatment holder of the eighth embodiment.
FIG. 4 is a plan view showing a state where 0 and a spacer 21 overlap. The basic configuration and manufacturing process of the eighth embodiment are the same as those of the fifth embodiment. However, the silicon wafer supporting portion 20 of the eighth embodiment does not have the silicon wafer contact portion 20b, The outer peripheral portion of the spacer 21 is used at two places. By arranging the outer periphery of each spacer 5 so that the wafer W cannot move, the wafer W can be positioned. With this structure, man-hours for forming the silicon wafer support portion 20 can be reduced. FIG. 33 is a perspective view showing a holder for substrate heat treatment using the silicon wafer support 20 according to the eighth embodiment. In the eighth embodiment, since the area occupied by the silicon wafer support 20 can be reduced, the cost of parts can also be reduced.

Embodiment 9 FIG. FIG. 34 shows a silicon wafer support 2 used for the holder for substrate heat treatment according to the ninth embodiment.
0 is a plan view. In the case of heat treatment up to about 1100 ° C., the material of the holder for substrate heat treatment is quartz glass, which can sufficiently withstand use. However, during the long-term use, it is deformed and expands like a vial barrel. Are often experienced. With respect to such deformation, it is possible to improve the resistance by using a prism instead of a cylinder as the shape of the boat support 23. When the boat support 23 is a prism, the support engagement portion 20d has a rectangular shape and an acute shape as shown in FIG. FIG. 3 shows an example of a spacer 28 used for the silicon wafer supporting portion 20 of the sixth embodiment.
It is shown in FIG. The shape of the hole 28a through which the rectangular boat strut 23 penetrates may be a rectangle corresponding to the cross-sectional shape of the strut 23, but the appearance of the spacer may be various shapes such as a coin shape, a square shape without a bottom, and an Ω shape. When a U-shaped spacer is used, the convex portion 28 is formed similarly to the case of the C-shaped spacer 27.
b is provided.

Embodiment 10 FIG. FIG. 36 shows the tenth embodiment.
FIG. 4 is a plan view of a silicon wafer supporting portion 20 used for the substrate heat treatment holder of FIG. When the silicon wafer support 20 is made of quartz, the tip of the silicon wafer support 20 may be bent by its own weight due to long-term use. A hole 20e was opened in addition to the hole 20a. Accordingly, it is possible to prevent the tip of the silicon wafer support portion 20 from being bent even when used for a long time.

Embodiment 11 FIG. FIG. 37 shows Embodiment 11
It is a top view which shows the silicon wafer support part 20 used for the holder for board | substrate heat treatment. In the eleventh embodiment, a large number of holes 20e are formed on the entire surface of the silicon wafer support portion 20 to reduce the overall weight. Even when the wafer W is placed, a load is applied to the entire silicon wafer support portion 20, so that a specific portion is not deformed by placing the wafer W.

Embodiment 12 FIG. The quartz glass plate is extremely excellent in planar accuracy as can be seen from being used for a mask of a stepper, a liquid crystal display device and the like. Therefore, when quartz glass is used as the material, the silicon wafer support portion 20 can maintain planar accuracy by cutting out from one plate. FIG. 39 is a plan view showing a state in which the silicon wafer supporting portion 20 is pulled out from one sheet material 30. A general quartz processing maker purchases quartz glass as a processing material from a quartz member maker, but the shape of the purchased member is limited to basic shapes such as square bars, cylinders, plates, and pipes. When the processing is performed, the silicon wafer supporting portion 20 is cut out from a very large single plate.
In this method, many unnecessary parts are generated as shown in FIG.

In the twelfth embodiment, as shown in FIG. 40, a quartz glass plate is formed as a small rectangular plate member 29 so as to surround these plate members 29 so that the silicon wafer supporting portion 20 can be cut out. Weld securely the connection part. By polishing the plate material 29 after welding, the planar accuracy can be increased to the same level as a single plate. It can be seen that unnecessary portions can be significantly reduced as compared with the case shown in FIG. Although vein-like swelling occurs in the welded portion, it can be flattened by polishing.

As described above, according to the twelfth embodiment, unnecessary quartz glass chips generated during the process of manufacturing the silicon wafer supporting portion 20 can be reduced, and the silicon wafer supporting article can be reduced from reused quartz glass chips. The part 20 can also be manufactured.

In each of the embodiments described above, a silicon wafer is exemplified as a substrate, but the present invention is not limited to this. The present invention can be applied to all substrates requiring heat treatment.

Each of the above-described embodiments is merely an example of the embodiment of the present invention, and the technical scope of the present invention is limitedly interpreted. It must not be. That is, the present invention can be embodied in various forms without departing from its spirit or its main features.

[0121]

Since the present invention is configured as described above, it has the following effects.

Since the support portion and the spacer can be manufactured separately, the planar accuracy of the support portion and the vertical spacing of the support portion are determined by the accuracy of the support portion and the spacer alone. A holder can be obtained. In addition, since the support can be sorted at the stage of manufacturing the spacer and the spacer, the holder for heat-treating the substrate can be obtained with higher accuracy. Further, by separating the support portion and the spacer, each of the support portion and the spacer can be mass-produced, and the manufacturing cost can be reduced.

Further, since the support and the spacer are engaged with the support, the support and the spacer can be securely held, and the workability of assembly can be improved.

Further, since the supporting portion or the engaging portion of the spacer is formed as a hole, and the support is penetrated through the hole, the support or the spacer can be reliably engaged with the support.

By forming the engaging portion of the support portion as a notch, it is possible to prevent the support portion from expanding toward the outside of the substrate heat treatment holder.

Further, the engaging portion of the spacer is formed as a notch,
By directing the notch to the outside of the holder for substrate heat treatment, it is possible to prevent the spacer from projecting outside the holder for substrate heat treatment. In addition, by directing the notch toward the inside of the holder for substrate heat treatment, interference between the substrate and the spacer can be suppressed.

In the engagement portion between the spacer and the column, the convex portion is formed on one of the spacer and the column and the concave portion is formed on the other, so that the convex portion and the concave portion can be engaged with each other. It is possible to prevent the spacer provided with the notch shape from coming off from the support.

Further, since the position of the hole of the support portion in the horizontal plane substantially coincides with the position of the center of gravity of the support portion in the horizontal plane, the support portion can be prevented from tilting during assembly. Therefore, the support portions can be stacked while checking the horizontal state, so that it can be manufactured while checking an error at the stacking stage, and a defect can be found and dealt with earlier.

Further, since the position of the center of gravity of the support portion on the horizontal plane is located on the opposite side of the contact portion with respect to the center of the hole of the support portion, the support portion is provided with the substrate actually placed on the support portion. Since the portion can be kept horizontal and the surface accuracy can be checked while the substrate is placed, it is possible to find and deal with a defect in the manufacturing stage.

Further, since the support portion and the spacer are vertically and closely contacted and fixed between the nut fastened to the upper end of the support and the pedestal, the heat treatment for the substrate can be performed without applying thermal deformation or thermal stress. A holder is obtained.

Further, since each of the support portion and the spacer is fixed by thermocompression bonding, the assemblability can be improved. In addition, since the upper and lower surfaces of the support and the spacer are mirror-finished, thermocompression bonding can be easily performed.

Further, by forming the support portion in a ring shape and forming a notch in the support portion at a position where the transfer device for transferring the substrate is inserted, the transfer device can be provided without reducing the contact area between the support portion and the substrate. Can be put in and out.

In addition, since the inside outer shape of the support portion at the position facing the cutout portion is wider than other regions, it is possible to prevent the transport means from interfering with the support portion.

Further, by providing a step on the substrate side of the support portion along the contact portion, it is possible to suppress the substrate from moving.

Further, since a plurality of notches are formed in the contact portion, it is possible to suppress the diffusion of heat around the substrate.

By arranging the spacers such that the outer shapes of the plurality of spacers arranged at the same height position are close to the outer shape of the substrate, it is possible to prevent the substrate from moving on the support.

By forming an opening in the support portion in a region other than the engagement portion with the support, it is possible to prevent the support portion from being bent by its own weight.

Further, by using quartz glass as a main material, it is possible to reduce the manufacturing cost.

Further, the holder for substrate heat treatment of the present invention
By using the substrate heat treatment apparatus having good in-plane temperature controllability of the substrate, it is possible to suppress occurrence of slip on the substrate even at a higher temperature. This makes it possible to configure a high-temperature specification substrate heat treatment apparatus without increasing the manufacturing cost.

In addition, since welding is performed only for fixing the pedestal and the column, which does not require accuracy, it is possible to prevent the accuracy of the supporting portion from being deteriorated by welding. In addition, it is possible to prevent the annealing process for removing distortion from affecting accuracy.

In addition, since the quartz glass plate is divided and welded into a required shape and integrated, unnecessary quartz glass chips generated during the manufacturing process can be reduced.

Further, it is possible to determine the structure of the boat in which the slip of the substrate during the heat treatment is suppressed at a low cost and in a short period of time.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an outline of a vertical heat treatment boat according to Embodiment 1 of the present invention.

FIG. 2 is a perspective view showing a state where a boat support is attached to a bottom plate.

FIG. 3 is a schematic view showing a method of attaching a spacer and a silicon wafer support to a boat support.

FIG. 4 is a schematic diagram showing a positional relationship between a hole in a silicon wafer supporting portion and a center of gravity.

FIG. 5 is a schematic diagram showing a positional relationship between a hole in a silicon wafer supporting portion and a center of gravity.

FIG. 6 is a perspective view showing a configuration of a boat support.

FIG. 7 is a perspective view showing an outline of a method of assembling the vertical heat treatment boat according to the first embodiment of the present invention.

FIG. 8 is a perspective view showing an outline of a method of assembling a vertical heat treatment boat according to a second embodiment of the present invention.

FIG. 9 is a perspective view showing a conventional vertical heat treatment boat.

FIG. 10 is a perspective view showing a conventional vertical heat treatment boat.

FIG. 11 is a schematic view showing a silicon wafer after heat treatment at a temperature of 1000 ° C. using the conventional vertical heat treatment boat shown in FIG. 9;

FIG. 12 is a view showing a silicon wafer after heat treatment at a temperature of 1050 ° C. by the conventional vertical heat treatment boat shown in FIG. 9;

FIG. 13 is a photographed image by the X-ray topography system after performing the heat treatment at a temperature of 1050 ° C. with the conventional vertical heat treatment boat shown in FIG.

FIG. 14 is a photographed image by the X-ray topography system after heat treatment at 1050 ° C. is performed by the vertical heat treatment boat of the first embodiment shown in FIG.

FIG. 15 is a plan view showing a positional relationship of a silicon wafer supporting portion of the vertical heat treatment boat according to the first embodiment shown in FIG.

FIG. 16 is a schematic diagram showing a state in which three boat pillars are set up at three equal positions from the center of a silicon wafer.

FIG. 17 is a schematic view showing a state in which the distance between boat posts is increased until a silicon wafer can be taken in and out in the state shown in FIG. 16;

FIG. 18 is a schematic diagram showing a shape and an arrangement state of a silicon wafer support portion of the vertical heat treatment boat according to the third embodiment of the present invention.

FIG. 19 is a schematic view showing an example of the shape of a silicon wafer support.

FIG. 20 is a schematic view showing an example of the shape of a silicon wafer support.

FIG. 21 is a schematic view showing an example of the shape of a silicon wafer support.

FIG. 22 is a perspective view showing a mating state between a boat support, a silicon wafer support, and a spacer according to Embodiment 4 of the present invention.

FIG. 23 is a plan view showing shapes of a boat support, a silicon wafer support, and a spacer according to Embodiment 4 of the present invention.

FIG. 24 is a plan view of a silicon wafer supporting portion according to a fifth embodiment of the present invention.

FIG. 25 is a perspective view showing a spacer according to a fifth embodiment of the present invention.

FIG. 26 is a perspective view showing a C-shaped spacer according to Embodiment 5 of the present invention.

FIG. 27 is a schematic diagram showing a lowermost spacer according to Embodiment 5 of the present invention.

FIG. 28 is a plan view illustrating a state in which a wafer placed on a transfer arm is transferred to a silicon wafer support unit according to a fifth embodiment of the present invention.

FIG. 29 is a perspective view showing a state where a jig for heat treatment of a substrate is completed using a silicon wafer supporting portion and a spacer according to a fifth embodiment of the present invention.

FIG. 30 is a plan view showing a state where a wafer is placed on a silicon wafer supporting portion according to a sixth embodiment of the present invention.

FIG. 31 is a plan view of a silicon wafer supporting portion according to a seventh embodiment of the present invention.

FIG. 32 is a plan view showing a state in which a wafer is placed on a silicon wafer support portion according to an eighth embodiment of the present invention and the wafer is fixed with spacers.

FIG. 33 is a perspective view schematically showing a holder for substrate heat treatment assembled using a silicon wafer support according to an eighth embodiment of the present invention.

FIG. 34 is a plan view showing a silicon wafer support according to a ninth embodiment of the present invention.

FIG. 35 is a perspective view showing a spacer according to a ninth embodiment of the present invention.

FIG. 36 is a plan view showing a silicon wafer support according to a tenth embodiment of the present invention.

FIG. 37 is a plan view showing a silicon wafer support according to an eleventh embodiment of the present invention.

FIG. 38 is a perspective view showing a state in which a boat support is erected on a bottom plate in a holder for substrate heat treatment commonly used in each embodiment of the present invention.

FIG. 39 is a plan view showing a quartz glass plate serving as a material for forming a silicon wafer support.

FIG. 40 is a plan view of a quartz plate glass used as a material for forming a silicon wafer supporting portion according to Embodiment 12 of the present invention.

FIG. 41 is a perspective view showing a boat support having a concave portion.

FIG. 42 is a characteristic diagram showing the relationship between the temperature and the viscosity coefficient of quartz glass.

FIG. 43 is a perspective view showing a conventional holder for heat treatment of a substrate made of quartz.

FIG. 44 is a perspective view showing a conventional substrate heat treatment holder made of silicon carbide or silicon carbide and partly silicon.

FIG. 45 is a schematic view showing a procedure for automatically transferring a wafer using a transfer arm in a conventional holder for substrate heat treatment.

FIG. 46 is a schematic view showing a procedure for automatically transferring a wafer by using a transfer arm in the conventional holder for substrate heat treatment, following FIG. 45;

FIG. 47 is a schematic view showing a procedure for automatically transferring a wafer using a transfer arm in a conventional holder for substrate heat treatment, following FIG. 46;

FIG. 48 is a perspective view showing a conventional holder for substrate heat treatment provided with a silicon wafer support member divided into two parts.

[Explanation of symbols]

1A, 1B, 1C, 1D, 1E Silicon wafer support, 2, 21, 27, 28 Spacer, 3, 23
Boat prop, 4 nuts, 5,25 top plate, 6,2
4 bottom plate (pedestal), 7 boat positioning groove, 8 top plate fixing column hole, 9 convex part, 10 fixing groove, 11
Center of gravity, 12 Silicon wafer contact part, 13 Silicon wafer support rod, 14 Silicon wafer contact part, 15
Si wafer support, 16 male screw, 18 reaction tube, 19 silicon wafer trisection, 20 silicon wafer support, 21, 27 spacer, 22 bottom spacer, 24 bottom plate, 26 transfer arm,
29,30 Quartz glass plate.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Ikuo Katsuta 2-14-8 Nihonbashi Kakigara-cho, Chuo-ku, Tokyo Omiya Chemical Co., Ltd. F term (reference) 5F031 CA02 HA05 HA42 HA62 HA63 HA64 MA28 MA29 MA30 PA11 PA13 PA18

Claims (27)

[Claims] 1. A holder for heat-treating a substrate that horizontally supports a plurality of substrates while vertically separating them from each other, a support portion that supports each of the plurality of substrates by surface contact, and the support portion in a vertical direction. A holder for heat treatment of a substrate, comprising: a spacer for defining an interval between the substrates. 2. A plurality of pillars which stand vertically on a pedestal to hold the support part and the spacer, wherein the support part has a contact part for supporting the substrate by surface contact and the pillar. An engaging portion to be engaged is formed, an engaging portion to be engaged with the support is formed in the spacer, and the support and the spacer are alternately engaged with the support. The holder for heat treating a substrate according to claim 1, wherein: 3. The holder according to claim 2, wherein the engaging portion of the support portion is a hole formed so as to penetrate the support portion. 4. A method according to claim 1, wherein said engaging portion of said support portion has a notch shape formed in said support portion, and at least a part of said notch shape is the same as a cross-sectional shape of said column. The holder for heat treating a substrate according to claim 2. 5. The holder according to claim 2, wherein the engaging portion of the spacer is a hole formed so as to penetrate the spacer. 6. A method according to claim 1, wherein said engaging portion of said spacer has a cutout shape formed in said spacer, and at least a part of said cutout shape is the same as a cross-sectional shape of said column. Item 5. The holder for heat treating a substrate according to any one of Items 2 to 4. 7. An engaging portion between the spacer and the column, wherein a convex portion is formed on one of the spacer and the column and a concave portion is formed on the other, and the convex portion and the concave portion are formed. 7. The holder according to claim 6, wherein the portions are engaged with each other. 8. A plurality of the support portions are provided for supporting one substrate, and a position of a hole of the support portion in a horizontal plane substantially coincides with a position of a center of gravity of the support portion in the horizontal plane. The holder for heat-treating a substrate according to any one of claims 2 to 7, wherein: 9. A plurality of the support portions are provided to support one substrate, and a position of a center of gravity of the support portion on a horizontal plane is defined by a position of the contact portion with respect to a center of a hole of the support portion. 3. The device according to claim 2, wherein the device is located on the opposite side.
8. The holder for heat treating a substrate according to any one of claims 7 to 7. 10. The apparatus according to claim 2, wherein said support portion and said spacer are sandwiched between a nut fastened to an upper end of said support and said pedestal, and are closely fixed in a vertical direction. 10. The holder for heat treating a substrate according to any one of claims 9 to 9. 11. The holder for heat treating a substrate according to claim 1, wherein each of said support portion and said spacer is fixed by thermocompression bonding. 12. The holder according to claim 11, wherein upper surfaces and lower surfaces of the support portion and the spacer are mirror-finished. 13. The support portion is formed in a ring shape, and a notch is formed in the support portion at a position where a transfer unit for transferring the substrate is inserted. 13. The holder for heat treating a substrate according to any one of items 12 to 12. 14. The holder for substrate heat treatment according to claim 13, wherein an outer shape inside the support portion at a position facing the notch portion is wider than another region. 15. The holder for heat treating a substrate according to claim 13, wherein a step is provided along the contact portion on the substrate side of the support portion. 16. The holder for heat treating a substrate according to claim 13, wherein a plurality of notches are formed in said contact portion. 17. The substrate according to claim 13, wherein the outer shapes of the plurality of spacers arranged at the same height position are arranged so as to be close to the outer shape of the substrate. Holder for heat treatment. 18. The holder for heat treating a substrate according to claim 13, wherein an opening is formed in said support portion in a region other than an engagement portion with said support post. 19. The holder for heat treating a substrate according to claim 1, wherein quartz glass is used as a main material. 20. A substrate heat treatment apparatus comprising the substrate heat treatment holder according to claim 1. Description: 21. A method for manufacturing a semiconductor device, comprising: performing a heat treatment on a substrate using the holder for heat-treating a substrate according to any one of claims 1 to 19. 22. A method for manufacturing a substrate heat treatment holder for horizontally supporting a plurality of substrates in a state where a plurality of substrates are vertically separated from each other, comprising the steps of: attaching and fixing a plurality of columns vertically to a pedestal; A step of alternately inserting a supporting portion for supporting the plurality of substrates and a spacer for defining a vertical interval between the supporting portions with respect to the support; and a step of closely contacting and fixing the supporting portion and the spacer. A method for manufacturing a holder for heat treating a substrate, comprising: 23. The method according to claim 22, wherein the supporting portion and the spacer are fixed in a state of being brought into close contact with each other by tightening a nut to an upper end of the column. 24. The substrate according to claim 22, further comprising a step of mirror-finishing the upper surface and the lower surface of each of the support portion and the spacer, wherein the support portion and the spacer are fixed by thermocompression bonding. Manufacturing method of holder for heat treatment. 25. The method according to claim 2, wherein welding is not performed in a step other than the step of fixing the support to the pedestal.
25. The method for producing a holder for heat treating a substrate according to any one of 2 to 24. 26. A step of welding a plurality of quartz glass plates so as to be adjacent to each other, a step of polishing the connected quartz glass plates, and a step of extracting the quartz glass plates before inserting the support portion into the columns. 26. The method according to claim 22, further comprising the step of: 27. The method for determining a structure of a holder for heat treating a substrate according to claim 1, wherein the heat treatment of the substrate is performed by mounting the support having different shapes. A method for determining a structure of a holder for heat treatment of a substrate, characterized by determining a shape of a substrate.