JPH10242067A - Substrate supporting tool for heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To support substrates to be treated, without causing the self wt. stress and avoid slipping the substrates being heat treated at high temps., by providing specified spacings in the vertical direction between flat plates supporting the entire lower faces of the substrates through posts. SOLUTION: A wafer boat 17 is capable of supporting many e.g. 150 disk-like semiconductor wafers W to be treated with specified spacings in the vertical direction and has flat support plates 22 for supporting the entire lower faces of the wafers W; the plates 22 are horizontally stacked through posts 23 with specified spacings. For wafers of 300mm diameter the adjacent plates 22 are spaced pref. 20mm. The wafer boat 17 may be called plate boat, the plate 22 and the posts 23 are pref. made of a heat-resistance material not contaminating wafer e.g. quarts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a substrate support for heat treatment.

[0002]

2. Description of the Related Art In the production of semiconductor devices, oxidation, diffusion, CVD (Chemical Chemistry)
Various heat treatment apparatuses are used for performing processes such as ical vapor deposition and annealing. In a vertical heat treatment apparatus, which is one of the heat treatment apparatuses, in order to heat-treat a large number of wafers at once in a batch type in a vertical heat treatment furnace, the wafers are horizontally supported in multiple stages at predetermined intervals in a vertical direction. A substrate support for heat treatment called a wafer boat is used. Some of these wafer boats are called ladder boats or ring boats depending on their structures.

The ladder boat has a plurality of (for example, 3 to 6) columns arranged so as to surround the periphery of the wafer, and these columns support the wafer in multiple stages at appropriate intervals in the vertical direction. A concave or convex locking portion is provided. The ring boat is provided with a ring-shaped support portion for supporting a peripheral portion of a wafer instead of the locking portion in the ladder boat. As the material of the support and the ring-shaped support portion, a material having heat resistance and hardly becoming a contamination source for the wafer, for example, quartz is used.

[0004]

However, in the above-mentioned conventional wafer boat, since the peripheral portion of the wafer is supported, the central region of the wafer is easily bent downward by its own weight. In particular, there is a problem that a slip (displacement of crystal) easily occurs on the wafer due to stress during high-temperature heat treatment, and the yield must be reduced.
Since such a problem increases as the diameter (diameter) of the wafer increases, it has become difficult to use the wafer boat for a wafer having a large diameter.

In a conventional wafer boat, the upper surface (front surface), which is the surface to be processed of a wafer, is in a supporting state in which it directly faces the lower surface (back surface) of the wafer located thereabove. For this reason, depending on the process, the film formation amount on the upper surface of the wafer may be affected by the material or film type of the back surface of the wafer directly above the wafer, and it is not suitable for such a process depending on the opposite back surface. There was a problem.

[0006] The present invention has been made to solve the above problems. An object of the present invention is to be able to support a large number of substrates to be processed so that no self-weight stress is generated, to prevent the substrates to be processed from slipping during high-temperature heat treatment, and to have a so-called opposite back surface dependency. It is an object of the present invention to provide a substrate support for heat treatment that can be applied to a process.

[0007]

In order to achieve the above object, a substrate support for heat treatment according to claim 1 of the present invention is provided for heat-treating a large number of substrates in a vertical heat treatment furnace. In a substrate support for heat treatment for supporting a processing substrate in a horizontal state at predetermined intervals in a vertical direction, a flat plate-like support plate for supporting the entire lower surface of the substrate to be processed is provided at predetermined intervals in a vertical direction via a support. It is characterized by:

According to a second aspect of the present invention, in order to transfer a substrate to be processed to the support plate, a support pin for supporting a lower surface of the substrate to be processed and vertically moving is inserted. Is formed.

The substrate support for heat treatment according to a third aspect of the present invention is characterized in that a concave portion for accommodating the substrate to be processed so as not to move horizontally is formed on the upper surface of the support plate.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing an example of a vertical heat treatment apparatus,
FIG. 3 is a front view of the wafer boat, FIG. 4 is a partially omitted perspective view showing an example in which the structure of the support of the wafer boat is changed, FIG. 5 is a schematic perspective view showing an example of a substrate transfer mechanism, and FIG. FIG. 9 is an explanatory diagram illustrating an operation of the substrate transfer mechanism.

First, FIG. 2 shows an example of a vertical heat treatment apparatus.
This will be described with reference to FIG. This vertical heat treatment apparatus is, for example, C
It has a vertical heat treatment furnace 1 configured to be suitable for VD processing. This vertical heat treatment furnace 1 has a vertically long cylindrical reaction tube 2 constituting a heat treatment chamber. This reaction tube 2
It is preferable to use a material having heat resistance and infrared transmittance, for example, quartz. The reaction tube 2 is preferably configured in a double tube structure including an inner tube 3 having an open upper end and a lower end, and an outer tube 4 having a closed upper end and an open lower end.

The lower end of the reaction tube 1 is connected to a cylindrical manifold 7 having a gas supply pipe 5 for supplying and exhausting a processing gas and the like and an exhaust pipe 6 on its side wall. The manifold 7 is preferably made of a material having corrosion resistance and corrosion resistance, for example, stainless steel. The manifold 7 is mounted on a base plate 8 horizontally arranged above via a mounting member (not shown).

At the upper end of the manifold 7, the outer pipe 4
The lower end of the inner pipe 3 is air-tightly connected, and the lower end of the inner pipe 3 is supported by a flange 9 formed inside the manifold 7. The gas supply pipe section 5 is provided so as to supply a processing gas or the like upward along the inside of the inner pipe 3, and the exhaust pipe section 6 has an annular shape between the inner pipe 3 and the outer pipe 4. The exhaust gas after the treatment is exhausted from the passage 10.

A heater 11 is arranged around the reaction tube 1 to heat the inside of the reaction tube 1 to a predetermined temperature, for example, 500 to 1200 ° C. This heater 11
A heater wire (heating resistance wire) 12 is formed in a coil shape so as to be wound around the reaction tube 1, the outside of the heater wire 12 is covered with a heat insulating material 13, and the outside of the heat insulating material 13 is provided with a cooling jacket or the like. It is preferable that the structure is covered with the outer shell 14. The heater 11 is provided on the base plate 8.

The lower end opening of the manifold 7 forming the furnace port of the vertical heat treatment furnace 1 is closed by a lid 15 so as to be openable and closable. The lid 15 is preferably made of a material having heat resistance and corrosion resistance, for example, stainless steel. A wafer boat 17 which is a substrate support for heat treatment, which will be described later, is removably mounted on the lid 15 via a thermal insulation tube 16 made of, for example, quartz. The wafer boat 17 has a large number of, for example, 150, disk-shaped semiconductor wafers W to be processed at predetermined intervals in a vertical direction in a horizontal state.
It is configured to be able to support about one sheet.

The lid 15 is attached to a lifting arm 19 of a lifting mechanism 18 so that the lid 15 can be opened and closed, and the wafer boat 17 can be carried in and out of the reaction tube 1 by the lifting mechanism 18. Has become. The lid 1
It is preferable that a rotating mechanism (not shown) for rotating the wafer boat 17 around an axis via the heat retaining cylinder 16 is provided in the 5. The gas supply pipe section 5 provided on the side wall of the manifold 7 is connected to a gas supply pipe 20 communicating with a supply source of a processing gas or the like, and the exhaust pipe section 6 is connected to an exhaust pipe 21 communicating with an exhaust system. ing. The evacuation system is provided with a decompression controller (not shown) having a not-shown vacuum pump or the like for evacuation of the inside of the reaction tube 1 to a predetermined decompression atmosphere or a vacuum degree, for example, 10 to 10 ^-8 Torr. I have.

The wafer boat 17 has a large number of flat support plates 22 for supporting the entire lower surface of the wafer W. These support plates 22 are horizontally supported by support columns 23 at predetermined intervals in the vertical direction. It has a multi-stage configuration. For a wafer having a diameter of 300 mm, a gap of 20 mm is preferably provided between the vertically adjacent support plates 22. Unlike the ladder boat and the ring boat, the wafer boat 17 has a flat support plate 22 that supports the entire lower surface of the wafer W, and thus can be called a plate boat. It is preferable that the support plate 22 and the support columns 23 constituting the wafer boat 17 are made of a material that has heat resistance and does not become a contamination source for the wafer, for example, quartz.

The support plate 22 is formed to have at least the same size (diameter) as the wafer W or a disk shape slightly larger than the wafer W in order to support the entire lower surface of the wafer W. Is preferred. The support columns 23 are arranged so as to support the peripheral portions of the support plates 22 arranged in multiple stages in the vertical direction in a horizontal state at appropriate intervals. In this case, one side of the wafer boat 17 is spaced from the support columns 23 so that the wafer W can be easily transferred from the side to each support plate 22 of the wafer boat 17 by the substrate transfer mechanism 24. , The opening 25 is opened as the transfer port 25 for transfer.

The support plate 22 is fixed to the column 23 by joining means, for example, welding. The above pillar 2
The number 3 and shape are not limited as long as 3 is a structure capable of firmly supporting the support plate 22. Therefore,
As shown in FIG. 1, the column 23 may be a plurality of round bar-shaped columns, for example, three to six columns. Alternatively, as shown in FIG. Those used more than this may be used.

The support plate 22 has support pins 2 to be described later.
In order to enable the transfer of the wafer W by the substrate transfer mechanism 24 having the support 6, an insertion hole (support pin insertion hole) 27 for vertically inserting a support pin 26 that supports the lower surface of the wafer W and moves up and down. Is preferably formed. It is preferable that the insertion holes 27 are formed with a small diameter corresponding to the support pins 26 of the substrate transfer mechanism 24 and a plurality of, for example, 3 to 4 (four in the illustrated example) interspersed at predetermined intervals. Unlike the ring of the ring boat, the insertion hole 27 has a small diameter, for example, 30 mm in diameter, and is sufficiently small as compared with the area of the support plate 22, so that there is almost no possibility that a self-weight stress is generated in the wafer W.

On the upper surface of the support plate 22, a concave portion 28 is formed to receive the wafer W so as not to move horizontally so as to prevent the wafer W from slipping off the support plate 22. Preferably (see FIG. 6).
When the wafer W has, for example, a diameter of 300 mm and a thickness of 1 mm, the support plate 22 has a diameter of about 320 mm and a thickness of 3.
It is preferably about 5 mm. Such a support plate 2
2, a concave portion 28 having a size capable of accommodating the wafer W is formed on the upper surface so as to have a depth of 0.5 m, for example, by spot facing.
m is preferable. This allows
An annular regulating protrusion 29 having a width of about 10 mm for regulating the periphery of the wafer W is formed on the periphery of the upper surface of the support plate 22.
Are formed. The concave portion 28 is flat and accurately processed so that the entire lower surface of the wafer W can be uniformly placed.

On the other hand, as the substrate transfer mechanism, for example, one described in Japanese Patent Application Laid-Open No. 3-83730 can be suitably used. An example of the substrate transfer mechanism will be described with reference to FIGS. This substrate transfer mechanism 2
Reference numeral 4 denotes a thin plate-shaped first substrate support arm 30 for supporting and transporting the lower surface of the wafer W, and is provided below the first substrate support arm 30 to support the lower surface of the wafer W during transfer. And a second substrate support arm 31 having a plurality of, for example, four support pins 26 standing up. Note that the second substrate support arm 31 does not necessarily have to be plate-shaped, but may be, for example, rod-shaped, and the rod-shaped arm may be provided with a support pin.

The support pins 26 are provided at the same height to support the wafer W horizontally. The upper end of the support pin 26 may be formed in a spherical shape. Further, two support pins 26 are provided on both sides at an interval wider than the width of the first substrate support arm 30 so as not to interfere with the first substrate support arm 30 when the wafer W is transferred. Is preferred.

First and second substrate support arms 30, 3
1 is provided on an arm support 33 that is rotatable about a horizontal axis with respect to a base 32 and that can be moved up and down.
The arm support 33 is configured to be independently movable in the same horizontal direction. Further, the second substrate support arm 31 is configured to be able to move up and down with a predetermined stroke, for example, about 10 mm, independently of the first substrate support arm 30. In order to transfer the wafers W between the wafer boat 34 and the wafer cassette 34 which is a transfer substrate housing container accommodating a plurality of, for example, 25 wafers W at predetermined intervals, the substrate transfer mechanism is used. A wafer cassette 34 and a wafer boat 17 are installed at predetermined positions around the wafer 24.

Next, the operation of the substrate transfer mechanism 24 will be described for a case where a wafer W is transferred from the wafer cassette 34 to the wafer boat 17. First, the arm support table 33 is rotated in the direction of the target wafer cassette 34, the first substrate support arm 30 is inserted into a lower portion of the wafer W at a desired position in the wafer cassette 34, and then slightly raised. The wafer W is placed on the first substrate support arm 30, and in this state, the first substrate support arm 30 is retracted, and the wafer W is extracted from the inside of the wafer cassette.

Next, the arm support 33 is moved to the wafer boat 1
7, the arm support 33 is moved up and down, and the height is adjusted so that the first substrate support arm 30 is positioned above the support plate 22 at the desired position of the wafer boat 17. Thereafter, the first and second substrate support arms 3
0, 31 are advanced together, as shown in FIG.
The first substrate support arm 30 is placed above the support plate 22 and the second
The substrate support arm 31 is positioned below the support plate 22.

Then, as shown in FIG. 6B, the second
Only the substrate support arm 31 is raised by a predetermined stroke to allow the support pin 26 to be inserted into the insertion hole 27 of the support plate 22, and the wafer W is pushed up by the support pin 26, so that the first substrate support arm 30 The wafer W is received on the support pins 26. Next, as shown in FIG. 6C, the first substrate support arm 30 is retracted and pulled out from between the wafer W and the support plate 22. Then, as shown in FIG. 6D, the second substrate support arm 31 is lowered to place the wafer W in the concave portion 28 of the support plate 22, and the support pins 26 are inserted into the insertion holes 27 of the support plate 22. Then, the second substrate support arm 31 is retracted, and the transfer of one wafer W is completed.

By repeating the above operation, the wafers W in the wafer cassette 34 are sequentially transferred to the wafer boat 17. Incidentally, the wafer cassette 17 is moved from the wafer boat 17 to the wafer cassette 34.
The transfer to is performed by performing an operation reverse to the above operation. As described above, the substrate transfer mechanism 24 includes the first substrate support arm 30 that horizontally supports and transports the wafer W,
The wafer W is pushed up from the lower side of the support plate 22 of the wafer boat 17 through the insertion hole 27 to support it, and a gap is formed between the support plate 22 and the wafer W so that the first substrate support arm 30 can be inserted and pulled out. And the second substrate supporting arm 31 having the supporting pin 26 to be
The transfer of wafers can be easily performed even in a wafer boat having the wafer boat 2.

The wafer boat 17 configured as described above
According to this, since the flat plate-like support plates 22 that support the entire lower surface of the wafer W are provided at predetermined intervals in the vertical direction via the columns 31, the multiple weights of the wafers W are not generated by their own weight stress. Can be fully supported. Thereby, the slip of the wafer W during the high-temperature heat treatment can be prevented, and the yield can be improved. Therefore, the wafer boat 17 can be easily applied to a wafer having a large diameter of 300 mm or more.

According to the wafer boat 17, since the upper and lower wafers W are separated from each other by the support plate 22, they are separated from each other. There is no direct opposition. Therefore, the present invention can be applied to a process having a so-called opposite back surface dependency without any problem.

Further, the support plate 22 is provided with an insertion hole 27 for vertically inserting a support pin 26 which supports the lower surface of the wafer W and moves up and down in order to transfer the wafer W. Therefore, transfer of the wafer W can be easily performed. Further, on the upper surface of the support plate 22, the wafer W
Is formed so as not to move horizontally, so that it is possible to prevent the wafer W from slipping and dropping off from the support plate 22.

Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-discussed preferred embodiments, and various design changes and the like are possible without departing from the gist of the present invention. Is possible. For example, as a substrate to be processed, for example, an LCD substrate or the like can be applied other than the semiconductor wafer. In addition, as a material of the substrate support for heat treatment,
In addition to quartz, for example, silicon carbide (SiC) or the like can be applied. The vertical heat treatment furnace may be configured to be suitable for, for example, oxidation treatment, diffusion treatment, annealing treatment, and the like, in addition to the CVD treatment.

The substrate transfer mechanism may be configured so that a plurality of sets of a first substrate support arm and a second substrate support arm are provided, and a plurality of wafers are transferred one by one. The mechanism for raising the wafer from above the support plate may be a mechanism for inserting a very thin fork-shaped substrate support arm between the wafer and the support plate to raise the wafer, or ejecting the base from the upper surface of the support plate. Or a mechanism that raises the wafer.

[0034]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) According to the substrate support for heat treatment according to the first aspect, a flat plate-like support plate for supporting the entire lower surface of the substrate to be processed is provided at predetermined intervals in the up-down direction via the support pillar. Therefore, it is possible to support a large number of substrates to be processed so that a self-weight stress does not occur, to prevent the substrates to be processed from slipping during a high-temperature heat treatment, and to perform a process having a so-called opposite back surface dependency. Applicable.

(2) According to the substrate support for heat treatment according to the second aspect, in order to transfer the substrate to be processed to the support plate, the support pins for supporting and lowering the lower surface of the substrate to be processed are provided. Because an insertion hole for inserting vertically is formed,
The substrate to be processed can be easily transferred.

(3) According to the substrate support for heat treatment of the third aspect, since the concave portion for accommodating the substrate to be processed so as not to move horizontally is formed on the upper surface of the support plate, the substrate to be processed is It is possible to prevent the skid from slipping off the support plate.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view showing an example of a vertical heat treatment apparatus.

FIG. 3 is a front view of a wafer boat.

FIG. 4 is a partially omitted perspective view showing an example in which the structure of the support of the wafer boat is changed.

FIG. 5 is a schematic perspective view showing an example of a substrate transfer mechanism.

FIG. 6 is an explanatory diagram illustrating an operation of the substrate transfer mechanism.

[Explanation of symbols]

 Reference Signs List 1 vertical heat treatment furnace W semiconductor wafer (substrate to be processed) 17 wafer boat (substrate support for heat treatment) 22 support plate 23 support 26 support pin 27 insertion hole 28 recess

Claims (3)

[Claims] 1. A heat treatment substrate support for supporting a plurality of substrates to be processed in a vertical heat treatment furnace at predetermined intervals in a vertical state in a horizontal state, wherein the entire lower surface of the substrate to be processed is provided. A heat-treating substrate support, characterized in that a flat support plate for supporting the substrate is provided at predetermined intervals in the vertical direction via a column. 2. The support plate has an insertion hole for vertically inserting a support pin that supports a lower surface of the substrate to be processed and moves up and down in order to transfer the substrate to be processed. The substrate support for heat treatment according to claim 1, wherein: 3. The substrate support for heat treatment according to claim 1, wherein a concave portion for accommodating the substrate to be processed so as not to move horizontally is formed on an upper surface of the support plate.