JP2001118802A - Vertical wafer boat and vertical heat treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical wafer boat for a vertical heat treatment device capable of performing heat treatment to a wafer with high uniformity in a surface, forming a film and reducing the particles attached to the wafer. SOLUTION: The present vertical wafer boat 40 stores plural wafers in many stages perpendicular to the central line in the longthwise direction of a cylindrical vertical furnace disposed in a heat treatment device. The present vertical wafer boat 40 has a column 44 provided on a base 42, two bifurcated arms 46A, 46B extending in parallel to the base 42 in a shape of letters U and V and disposed at equal intervals along the direction of height of the column 44, and support points 48A to 48C provided on the base end portion for connecting the two arms and on the tip ends of the two arms 46A, 46B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical wafer boat and a heat treatment apparatus for accommodating a wafer and inserting the wafer into a vertical furnace, and more particularly, to forming a film with good in-plane uniformity of a wafer. The present invention relates to a vertical wafer boat and a heat treatment apparatus configured to perform heat treatment and reduce particles attached to a wafer.

[0002]

2. Description of the Related Art A heat treatment apparatus provided with a vertical furnace is an apparatus capable of processing a large number of wafers at a time in a vertical furnace, for example, as a thermal oxidation apparatus for forming a thermal oxide film on a large number of wafers. It is widely used in the manufacturing process of semiconductor devices. In addition, a heat treatment apparatus equipped with a vertical furnace, for example, ion-implants impurities into a wafer and then activates the impurities by performing a heat treatment. It is widely used as a processing device. In this specification, the heat treatment apparatus provided with a vertical furnace is a heat treatment apparatus of a broad concept including a thermal oxidation apparatus and a heat treatment apparatus.

Here, the configuration of a vertical furnace provided in a heat treatment apparatus will be described with reference to FIG. FIG. 4 is a schematic sectional view showing the configuration of a vertical furnace of a heat treatment apparatus, and FIG. 5 is a perspective view of a conventional vertical wafer boat. As shown in FIG. 4, the vertical furnace 10 includes a cylindrical, covered quartz outer core tube 12 and a cylindrical, quartz inner core tube 14 provided concentrically within the quartz outer core tube 12.
And an annular heater 16 provided outside the quartz outer core tube 12.
The inside of the quartz inner core tube 14 constitutes a furnace chamber 17. A gas inlet 18 and an exhaust port 20 are provided on both side walls at the lower portion of the quartz outer core tube 12. Further, at the bottom of the quartz outer core tube 12, a boat port 24 functioning as an opening for sending and receiving a vertical wafer boat 22 described later is provided. The boat port 24 is opened when the vertical wafer boat 22 is loaded, and when the wafer W is heat-treated, the furnace chamber 1 is opened.
7 is closed by a rotating disk 23 which is a rotating disk rotatable around a longitudinal center line of the rotating disk 7 and constitutes a detachable door, and the vertical wafer boat 22 is rotated by the rotation of the rotating disk 23 so that the vertical wafer boat 22 is positioned at the longitudinal center. Rotate around the line. The turntable 23 is
It is rotated by the driving of a driving device (not shown).

When heat treatment is performed on wafers, a vertical wafer boat 22 in which a large number of wafers W are placed horizontally and separated from each other.
Is sent upward from the boat port 24 at the bottom of the quartz outer core tube 12, and is placed in the furnace chamber 17 of the quartz inner core tube 14.

[0005] The conventional vertical wafer boat 22 is generally formed of quartz, and as shown in FIG.
A bottom plate 27 provided on a base 26, three columns 28 standing upright on the bottom plate 27, and an annular ceiling plate 30 for fixing upper ends of the three columns 28 are formed. Further, the vertical wafer boat 22 is provided with the support portions 32 at the same height at substantially the same intervals along the columns 28, and the wafers W are loaded one by one by the three support portions 32. It is designed to be placed. In order to secure a frontage through which the wafer W can be inserted between the columns 28, the columns 28
Along a half circumference smaller than 180 °, for example, 4
It stands upright at intervals of about 0 °. The support part 32 includes the support 2
8, a small projection is projected inward, and the wafer W
Or a support 28 on which the support 28 is mounted.
Alternatively, a groove-shaped support portion may be formed in which a groove is formed and the peripheral portion of the wafer W is inserted into the groove and supported. The base 26 of the vertical wafer boat 22 also serves as a heat retaining section, and is fixed to the rotating disk 23 of the vertical furnace 10. As another type of vertical wafer boat, a vertical wafer boat having four columns and four supports is also used.

[0006]

However, the conventional vertical wafer boat used in the vertical furnace has the following problems. First, since the number of columns is large, it is difficult for the air flow in the furnace chamber 17 to flow in a uniform and uniform flow. There is a problem that the film thickness is different from the region near the column of the wafer, and the uniformity of the film thickness in the wafer surface is poor. Therefore, a heat treatment apparatus provided with a vertical furnace has become incompatible with a wafer miniaturization process required with recent miniaturization of semiconductor devices.

Second, the particle adhesion rate to the wafer is high. When the heat treatment is performed in the vertical furnace, reaction products generated during the heat treatment reaction adhere to and deposit on the columns 28 of the vertical wafer boat 22 housed in the furnace chamber 17. Then, the reaction product deposited on the support 28 separates from the support 28, falls and adheres to the wafer W as particles or dust, and it is difficult to perform uniform and uniform processing in the subsequent process steps, and the product yield is increased. A problem of lowering the In a conventional vertical wafer boat, the number of pillars is three or more, and the number of pillars is large, so this problem is remarkable.

Thirdly, the conventional vertical wafer boat made of quartz has a problem that the quartz has a large thermal expansion coefficient and is easily deformed by heat during heat treatment, and cracks (cracks) occur due to the heat deformation. However, there has been a problem that it is liable to be generated on the surface and thus easily damaged. As a result, the cost for replacing the vertical wafer boat increases, and it has been difficult to improve the productivity of the heat treatment apparatus. Fourth, there is a problem that a four-post, four-support vertical wafer boat is expensive because high processing accuracy is required. Further, it is difficult to stably support the wafer with the four-point support, and it is difficult to transfer the wafer stably when placing the wafer on a vertical wafer boat. As a result, it takes time to adjust the transfer device, and it is difficult to improve the productivity.

An object of the present invention is to provide a vertical wafer boat having a structure capable of forming a film with high uniformity within a wafer surface, performing a heat treatment, and reducing particles adhering to a wafer. It is to provide a vertical heat treatment apparatus.

[0010]

SUMMARY OF THE INVENTION The present inventor has found that when thermal oxidation or heat treatment is performed in a vertical furnace using a conventional vertical wafer boat, the in-plane uniformity of the wafer is poor, and particles are deposited on the wafer. It is thought that the major reason that the particles adhere to the surface and hinder the subsequent process steps is that there are a large number of columns, so that the uniformity within the wafer surface is improved and the particles adhered to the wafer are reduced. Thought that it was necessary to reduce the number of pillars to two or less, and completed the present invention after experiments.

In order to achieve the above object, based on the above findings, a vertical wafer boat according to the present invention (hereinafter referred to as the first invention) is provided with a longitudinal center line of a cylindrical furnace chamber of a vertical furnace. The vertical wafer boat accommodates a plurality of wafers in a plurality of stages orthogonally to and is disposed in a furnace chamber of a vertical furnace provided in the heat treatment apparatus.
Two arms, which are provided at equal intervals along the height direction of the pillar and extend in a bifurcated shape including a U-shape and a V-shape from the pillar in parallel with the base; And a support point for supporting a wafer provided at a distal end of the two arms and at a common base end of the two arms.

The base referred to in the present invention is a base of a vertical wafer boat on which a column is to be built, for example, a base which also serves as a heat retaining section, which will be described later, or a door which closes a vertical wafer boat insertion opening of a vertical furnace. It refers to the base of the vertical wafer boat when fixing the vertical wafer boat to the turntable. 2 extending in a U-shape
The U-shaped shape of the book arm is not limited as long as the wafer can be stably held, and may be, for example, a semi-annular shape. Also,
The angle between the two V-shaped arms is not limited as long as the wafer can be stably held, for example, from 50 ° to 90 °.
Rank. Also, the two V-shaped arms at the base end,
They may be separated from each other, in which case a support point for supporting the wafer is provided on a support in the middle of the base ends of the two arms. The length of each arm should be such that when the wafer is placed with the periphery of the wafer close to the column, the arm extends to a point near or slightly beyond the periphery of the wafer in the direction in which the arm extends. The position where the point is provided should not exceed the periphery of the wafer.

Another vertical wafer boat according to the present invention (hereinafter referred to as a second invention) is a vertical wafer boat having two columns, and a longitudinal center line of a cylindrical furnace chamber of a vertical furnace. The vertical wafer boat accommodates a plurality of wafers in a plurality of stages orthogonally to the vertical wafer boat and is disposed on the base of the vertical wafer boat in the furnace chamber of the vertical furnace provided in the heat treatment apparatus. And two arms that are spaced apart from each other along the height direction of the pillar, extend in parallel with the base from the two pillars, and are connected to each other at their tips by crossing each other. And a support point for supporting a wafer provided at a base end of each of the two arms and a connecting end of the two arms.

Preferably, the vertical wafer boat is made of SiC in order to suppress thermal deformation of the vertical wafer boat and prevent damage such as cracks from occurring. In order to improve the productivity of the heat treatment, the vertical wafer boat preferably has at least 100 steps of arms.

The heat treatment apparatus according to the present invention comprises: a quartz outer tube having a cylindrical shape and a cover; a cylindrical inner tube having upper and lower openings concentrically provided in the outer tube; An annular heater provided outside of the quartz inner core tube as a furnace chamber, a reaction gas is introduced from one side of the lower portion of the quartz outer core tube, and the other of the lower portion of the quartz outer core tube is provided. In the vertical heat treatment apparatus, the vertical wafer boat according to any one of claims 1 to 3 is arranged in a furnace chamber. Preferably,
A boat port provided at the bottom of the quartz outer core tube for loading and unloading the vertical wafer boat is closed by a rotating disk that is rotatable around the longitudinal center line of the furnace chamber during the heat treatment of the wafer W, and The vertical wafer boat is rotated around the longitudinal center line of the furnace chamber by the rotation of the turntable. As a result, the wafer can be further uniformly processed in the plane of the wafer,
A film can be formed.

The vertical wafer boat of the present invention has a smaller number of columns than conventional vertical wafer boats, so that the airflow and temperature in the furnace chamber of the vertical furnace can be kept uniform and uniform. During film formation, the in-plane uniformity of the film thickness is improved, and the in-plane uniformity of the processing during the heat treatment is improved. Also,
Since the number of columns is small, the number of particles adhering to the wafer can be reduced as compared with a conventional vertical wafer boat. Further, the vertical heat treatment apparatus using the vertical wafer boat according to the present invention can cope with recent miniaturization processes, and can produce high quality semiconductor device products with high product yield.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 This embodiment is an example of an embodiment of a vertical wafer boat according to the first invention. FIG. 1A is a side view of a vertical wafer boat according to the present embodiment, and is viewed from an arrow I in FIG.
It is a side view of -I. FIG. 1B is a top view of the vertical wafer boat of the embodiment. The vertical wafer boat 40 of this embodiment accommodates a plurality of wafers W in multiple stages perpendicular to the longitudinal center line of the furnace chamber of the cylindrical vertical furnace 17 of the vertical furnace 10 as shown in FIG. And a vertical wafer boat arranged in the furnace chamber 17.

The vertical wafer boat 40 is formed of SiC and, as shown in FIG. 1, is separated from one support 44 provided on a base 42 at equal intervals along the height direction of the support 44. Provided at the distal ends of the two arms 46A and B and the connecting base ends of the two arms 46A and B, respectively.
A to C.

The two arms 46A, 46B extend parallel to the base 42 from the struts 44, respectively, such that they join together to form a semi-annular ring having a diameter slightly smaller than the diameter of the wafer W. I have. The support points 46A to 46C are each formed as a hemispherical projection. Two arms 46
A and B are provided in multiple stages with 100 stages along the columns 44 so that one heat treatment can process 100 wafers. The base 42 is a relatively heavy base that also functions as a heat retaining unit, and 100 wafers W
Even if it is placed, it will not fall down.

Embodiment 2 This embodiment is another example of the embodiment of the vertical wafer boat according to the first invention. FIG. 2A is a side view of the vertical wafer boat according to the embodiment, and is viewed from an arrow in FIG.
It is a side view of II-II. FIG. 2B is a top view of the vertical wafer boat of the embodiment. The vertical wafer boat 50 of the first embodiment is different from the vertical wafer boat 4 of the first embodiment.
Similarly to FIG. 4, a plurality of wafers W are accommodated in multiple stages orthogonal to the longitudinal center line of the furnace chamber of the cylindrical vertical furnace 17 of the vertical furnace 10 as shown in FIG. Vertical wafer boat.

The vertical wafer boat 50 is formed of SiC, and is spaced apart from one support 54 provided on a base 52 at equal intervals along the height direction of the support 54, as shown in FIG. Support points for supporting the wafers provided on the two arms 56A, B, and on the support columns 54 between the distal ends of the two arms 46A, B and the proximal ends of the two arms 46A, B, respectively. 58A-C.

The two arms 56A and 56B are separated from each other at the base end and connected to the column 54, and extend parallel to the base 52 so as to form a V-shape from the base end to the tip end. In this embodiment, the included angle between the two arms 56A and 56B is about 65 °. The length of the arms 56A, B extends to a point near or slightly beyond the periphery of the wafer W in the direction in which the arms 56A, B extend when the wafer W is placed with the periphery of the wafer W close to the column 56. However, the supporting points 58A and 58B do not exceed the peripheral edge of the wafer W. The two arms 56 </ b> A and B are provided in multiple stages along the columns 54 with 100 stages, and 100 heat treatments are performed by one heat treatment.
One wafer can be processed. Base 52
Is a relatively heavy base that also functions as a heat retaining unit, and does not fall even if 100 wafers W are placed.

Embodiment 3 This embodiment is an example of an embodiment of a vertical wafer boat according to the second invention. FIG. 3A is a side view of the vertical wafer boat according to the present embodiment, and is viewed from an arrow II in FIG.
It is a side view of I-III. FIG. 3B is a top view of the vertical wafer boat of this embodiment. The vertical wafer boat 60 of the present embodiment is similar to the vertical wafer boat 40 of the first embodiment in that the longitudinal center of the furnace chamber of the cylindrical vertical furnace 17 of the vertical furnace 10 as shown in FIG. The vertical wafer boat accommodates a plurality of wafers W in multiple stages perpendicular to the line and is disposed in the furnace chamber 17.

The vertical wafer boat 60 is formed of SiC and, as shown in FIG. 3, extends along two columns 64A, B provided on a base 62 and a height direction of the two columns 64. Two arms 66A, B provided at equal intervals and
And a connecting arm 67 for connecting the two arms 66A and 66B. The two arms 66A, B are provided with two columns 6
4A and 4B extend in parallel to the base 62, and are connected to each other at the tip portions so as to cross each other. Support points 68A to 68C for supporting the wafer are provided at the distal end connecting portion and the base ends of the two arms 66A and 66B, respectively.

The length of the arms 66A and 66B is such that when the peripheral edge of the wafer W is placed close to the two columns 66,
The support point 68A on the distal end connecting portion of the arms 66A and 66B has a length not exceeding the peripheral edge of the wafer W and a length equal to or longer than the radius of the wafer W. Two arms 66A, B
Are provided in multiple stages of 100 steps along the two columns 64A and 64B, so that 100 wafers can be processed by one heat treatment. The base 62 is a relatively heavy base that also functions as a heat retaining unit, and does not fall over even when 100 wafers W are placed thereon.

In the vertical wafer boats 40, 50, and 60 of the first to third embodiments, the number of columns is smaller than that of the conventional vertical wafer boat, so that the number of particles adhering to the wafer is reduced. Can be done. Also,
Since the number of pillars is small, the airflow and temperature in the furnace chamber of the vertical furnace can be kept uniform and uniform compared to conventional vertical wafer boats. The in-plane uniformity is improved, and the in-plane uniformity of the heat treatment is improved.

[0027]

According to the present invention, the number of pillars can be reduced as compared with the conventional vertical wafer boat, so that the lower part of the particles adhering to the wafer can be reduced as compared with the conventional vertical wafer boat. Can be. In addition, since the number of columns is small, the airflow and temperature in the furnace chamber of the vertical furnace can be kept uniform, so that in-film uniformity of the film thickness is improved during film formation, In-plane uniformity of the processing at the time is improved. The vertical heat treatment apparatus using the vertical wafer boat according to the present invention can cope with recent miniaturization processes, and can produce high quality semiconductor device products with high product yield.

[Brief description of the drawings]

FIG. 1A is a side view of a vertical wafer boat according to a first embodiment, and is a side view taken along a line II in FIG. 1B. FIG. 1B is a top view of the vertical wafer boat of the first embodiment.

FIG. 2A is a side view of a vertical wafer boat according to a second embodiment, and is a side view taken along a line II-II in FIG. 2B. FIG. 2B is a top view of the vertical wafer boat according to the second embodiment.

FIG. 3A is a side view of a vertical wafer boat according to a third embodiment, and is a side view taken along line III-III in FIG. 3B. FIG. 3B is a top view of the vertical wafer boat according to the third embodiment.

FIG. 4 is a schematic sectional view showing a configuration of a vertical furnace of the heat treatment apparatus.

FIG. 5 is a perspective view of a conventional vertical wafer boat.

[Explanation of symbols]

10 vertical furnace, 12 quartz outer core tube, 14 quartz inner core tube, 16 annular heater, 17 furnace chamber, 18 gas inlet, 20 exhaust outlet, 22 ... vertical wafer boat, 23 ... door, 24 ... boat mouth, 26 ... base, 2
7 ... Bottom plate, 28 ... Post, 30 ... Ceiling plate, 32 ...
Support part, 40... Vertical wafer boat of the first embodiment, 4
2 ... base, 44 ... support, 46 ... arm, 48 ...
Support point for wafer support, 50... Vertical wafer boat of embodiment 2, 52... Base, 54... Support, 56... Arm, 58... Support point for wafer support, 60. Vertical wafer boat of Example 3, 62... Base, 64... Support, 66... Arm, 67... Connection arm, 68.

Claims (6)

[Claims] 1. A vertical furnace which accommodates a plurality of wafers in a plurality of stages perpendicularly to a longitudinal center line of a cylindrical furnace chamber of a vertical furnace and is disposed in a furnace chamber of a vertical furnace provided in a heat treatment apparatus. In the type wafer boat, one support provided on the base of the vertical wafer boat is provided at regular intervals along the height direction of the support, and
Two arms extending in parallel from the support to the base in a bifurcated shape including a V-shape and a V-shape, and a wafer provided at a distal end of the two arms and a common base end of the two arms, respectively. A vertical wafer boat having a support point for support. 2. A vertical furnace which accommodates a plurality of wafers in a plurality of stages perpendicularly to a longitudinal center line of a cylindrical furnace chamber of a vertical furnace and is disposed in a furnace chamber of a vertical furnace provided in a heat treatment apparatus. In the type wafer boat, two columns are provided on the base of the vertical type wafer boat and are separated from each other along the height direction of the columns, and extend from the two columns in parallel with the base. And two arms connected to each other at the distal ends thereof, and a support point for wafer support provided at each of the base ends of the two arms and the distal end of the connection between the two arms. A vertical wafer boat comprising: 3. The vertical wafer boat according to claim 1, wherein the vertical wafer boat is formed of SiC. 4. The vertical wafer boat according to claim 1, wherein at least 100 steps of arms are provided along the columns. 5. A quartz outer core tube having a cylindrical shape and a cover, a cylindrical inner core tube having upper and lower ends opened concentrically within the outer quartz tube, and a quartz outer core tube provided outside the outer quartz tube. An annular heater is provided, and the inside of the quartz inner core tube is configured as a furnace chamber, and a reaction gas is introduced from one side of the lower portion of the quartz outer core tube and exhausted from the other side of the lower portion of the quartz outer core tube. A vertical heat treatment apparatus, wherein the vertical wafer boat according to any one of claims 1 to 3 is arranged in a furnace chamber. 6. A boat port provided at the bottom of a quartz outer core tube for loading and unloading a vertical wafer boat is rotatable around a longitudinal center line of a furnace chamber during heat treatment of a wafer W. 6. The vertical heat treatment apparatus according to claim 5, wherein the vertical wafer boat is closed by a rotary disk and the vertical wafer boat is rotated around a longitudinal center line of the furnace chamber by rotation of the rotary disk.