JP2001110731A - Vertical furnace for semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly control the vacuum level, gas density, and temperature inside each semiconductor wafer to be treated in batch treatment at a time. SOLUTION: Each pole 104A of a boat 104 is provided with grooves in which each wafer 103 is held so as to be inclined so that each wafer 103 set in the groove can be inclined with a prescribed angle with respect to a rotary driving shaft. Therefore, the wafers 103 held to be inclined can be rotated according to the rotation of the board 104, and gas between the wafers 103 and an inside inner tube 110 and an outside inner tube 109 can be stirred. Also, the pole 104A of the boar 104 is provided with plural fins 112 for stirring gas, and the gas between the wafers 103 and the inside inner tube 110 and the outside inner tube 109 can be stirred according to the rotation of the fins 112.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vertical furnace for a semiconductor manufacturing apparatus for performing various operations such as film formation on a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, in a vertical furnace of a semiconductor manufacturing apparatus such as a vertical CVD furnace or a vertical diffusion furnace, a large number of semiconductor wafers are held at predetermined intervals in a plate thickness direction in a boat in a furnace tube. While rotating each semiconductor wafer by the boat, inject various gases into the furnace tube,
By performing the heating, various operations are performed by a batch method (a method of simultaneously producing a large number of wafers). By the way, in such a vertical furnace, a semiconductor wafer processed in one batch processing (hereinafter, referred to as a wafer in a batch)
It is important to keep the degree of vacuum, gas concentration, and temperature uniform in each wafer surface, and various measures have been taken toward it.

Hereinafter, such a conventional vertical furnace will be specifically described. FIG. 9 is a cross-sectional view showing a structural example of such a conventional vertical furnace, and FIG. 10 is a side view showing an appearance of a boat used in the vertical furnace shown in FIG. In this vertical furnace, a large number of semiconductor wafers 3 held by a quartz or ceramic boat 4 are sealed with a cylindrical quartz furnace tube 1 and a hatch 6. Boat 4
Has a column 4A for horizontally holding a large number of semiconductor wafers 3 at predetermined intervals, and includes a rotary drive mechanism for rotating each semiconductor wafer 3 horizontally and rearward in the furnace tube 1. A heater 2 for heating the inside of the furnace tube 1 is disposed outside the furnace tube 1, and an outer inner tube 9 and an inner inner tube 10 are provided inside the furnace tube 1. I have.

A gas inlet pipe 7 for supplying gas to the inside of each of the inner tubes 9 and 10 is provided below the furnace tube 1 sealed by the hatch 6, and a pump 5 is provided outside the furnace tube 1.
Is provided. The gas supplied from the gas introduction pipe 7 passes between the inner inner pipe 10 and the outer inner pipe 9 and the furnace core pipe 1 and is exhausted by the pump 5. As described above, the inner pipes 9 and 10 are provided inside the furnace tube 1 to control the gas flow, and the boat 4 is provided with a rotation mechanism to rotate each semiconductor wafer 3, so that the wafer surface of the wafer in the batch is Some measures have been taken to keep the degree of vacuum, gas concentration and temperature in the inside uniform.

[0005]

As described above, in the conventional vertical furnace, the degree of vacuum, the gas concentration and the temperature within each wafer surface of the semiconductor wafer processed in one batch process are kept uniform. Although various countermeasures have been taken, it is still difficult to achieve perfect uniformity for the following reasons (A) and (B). (A) The gas concentration and temperature in the upper and lower parts of the furnace vary, and as a result, the film thickness is not stable. Therefore, the range that cannot be used for production is dealt with by placing dummy wafers in the furnace. For this reason, there was a problem that waste was large. (B) Because of the batch-type production, the gap between the semiconductor wafers is small, and it is difficult for the film forming gas or the like to reach the center of the wafer. As a result, for example, the film thickness in the surface of the semiconductor wafer is generated thicker in the outer peripheral portion.

Accordingly, an object of the present invention is to provide a vertical type semiconductor manufacturing apparatus capable of controlling the degree of vacuum, gas concentration and temperature in each wafer surface of a semiconductor wafer processed in one batch process more uniformly. To provide a furnace.

[0007]

In order to achieve the above object, the present invention provides a furnace tube for performing various operations on a semiconductor wafer and a plurality of semiconductor wafers housed in the furnace tube and arranged in a predetermined thickness direction. In a vertical furnace of a semiconductor manufacturing apparatus having a boat that is rotated and driven while being held at intervals, the boat holds each semiconductor wafer at a predetermined angle with respect to the rotation drive shaft, and holds each semiconductor wafer. The gas in the furnace tube is agitated by the rotation of. Further, the present invention provides a semiconductor having a core tube for performing various operations on a semiconductor wafer, and a boat housed in the core tube and rotating and driving a plurality of semiconductor wafers at predetermined intervals in a plate thickness direction. In the vertical furnace of the manufacturing apparatus, the boat has a plurality of columns for engaging and holding an outer peripheral portion of a semiconductor wafer, and the columns are provided with fins for stirring gas in a furnace tube. .

In a vertical furnace of a semiconductor manufacturing apparatus according to the present invention, for example, a predetermined gas is supplied into a furnace tube and heated to a predetermined temperature, and a large number of semiconductor wafers held by a boat are heated in the furnace tube. By rotating, work such as film formation by a batch method is performed. Each semiconductor wafer held by the boat is held in a state of being inclined by a predetermined angle with respect to a rotation drive shaft of the boat, so that when each semiconductor wafer rotates, the gas in the furnace tube is stirred. Therefore, for example, the gas filled in the furnace tube is controlled to have a uniform concentration in the furnace tube by the stirring action due to the rotation of each semiconductor wafer, and the temperature in the furnace tube is also controlled uniformly, so that they are close to each other. The wafers are evenly supplied over the entire surface of the wafers in the batch arranged in a batch. As a result, uniform processing can be performed on the surface of each semiconductor wafer, and a semiconductor having uniform characteristics can be manufactured. Also, the number of dummy wafers required in the conventional technology can be reduced,
Lean processing can be obtained.

In the vertical furnace of the semiconductor manufacturing apparatus according to the present invention, the boat is provided with fins.
As the fins rotate, the gas in the furnace tube is agitated. Therefore, for example, the gas charged in the core tube is
By the stirring action by the rotation of the fins, the concentration is controlled to be uniform in the furnace tube, and the temperature in the furnace tube is also controlled uniformly. Will be supplied. As a result, uniform processing can be performed on the surface of each semiconductor wafer, and a semiconductor having uniform characteristics can be manufactured. In addition, the number of dummy wafers required in the related art can be reduced, and a lean process can be obtained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a vertical furnace of a semiconductor manufacturing apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings. The vertical furnace of the semiconductor manufacturing apparatus according to the present embodiment, when a large number of semiconductor wafers are placed in a vertical furnace by a batch method to perform processing such as film formation, the film thickness and the entire surface of each semiconductor wafer In order to achieve uniform film quality etc., use a boat with a structure that can tilt and set each semiconductor wafer with respect to the rotation drive axis, and rotate the boat with each semiconductor wafer tilted, so that the semiconductor wafer itself At the same time as the inside of the furnace is agitated, an air flow is generated in the gap between the semiconductor wafers, so that the gas concentration distribution and the temperature distribution in the furnace and on the wafer surface are made uniform. In this embodiment, a vertical CVD method for growing a formed film on a semiconductor wafer surface in a quartz furnace tube is used.
A case in which the present invention is applied to a semiconductor manufacturing apparatus such as a furnace or a vertical diffusion furnace in which impurities are thermally diffused or thermally oxidized will be described.

FIG. 1 is a sectional view showing a structural example of a vertical furnace of a semiconductor device according to the present embodiment. FIG. 2 is a side view showing an appearance of a boat used in the vertical furnace shown in FIG. is there. FIG. 3 is a plan view showing a state in which the semiconductor wafer is held by the boat shown in FIG. In this vertical furnace, a large number of semiconductor wafers 103 held by a quartz or ceramic boat 104 are sealed with a cylindrical quartz core tube 101 and a hatch 106. The boat 104 holds a large number of semiconductor wafers 103 at predetermined intervals in the thickness direction thereof, and has four columns 104A that hold the semiconductor wafers 103.
Each of the columns 104A has a groove for locking the outer peripheral edge of the semiconductor wafer 103, and as shown in FIG. 3, the outer peripheral edge of the semiconductor wafer 103 is locked at four points. Are held in multiple stages at predetermined intervals in the vertical direction.

The boat 104 of this embodiment holds the semiconductor wafers 103 not horizontally but at a fixed inclination angle. This can be easily realized by providing the grooves of the respective columns 104A for holding one semiconductor wafer 103 at different height positions instead of at the same height position. Note that each semiconductor wafer 103
Are arranged parallel to each other in the thickness direction. At the lower end of the boat 104, a rotation drive mechanism (not shown) for rotating each semiconductor wafer 103 in the furnace tube 101 is built in, and each semiconductor wafer 103 is rotated integrally. The rotary drive shaft of the rotary drive mechanism is provided in the vertical direction. Therefore, the plate thickness direction of each semiconductor wafer 103 held not horizontally but inclined as described above has a predetermined inclination angle with respect to the direction of the rotary drive shaft.

As shown in FIG. 3, each support 104A
Indicates that approximately half of the outer peripheral edge of the semiconductor wafer 103 is 4
It is something that is held at a point. When the semiconductor wafer 103 is obliquely held by the columns 104A as described above, as shown in FIG. 2, the column 1 is formed with the edge of the semiconductor wafer 103 on the column 104A side inclined downward.
04A, each column 1 of the semiconductor wafer 103
It is designed to be mounted such that the edge on the side without 04A is arranged upward.

Outside the furnace tube 101, a heater 102 for heating the inside of the furnace tube 101 is arranged, and inside the furnace tube 101, an outer inner tube 10 is provided.
9 and an inner inner tube 110 are provided. Also, hatch 1
06, a gas introduction pipe 1 for supplying gas to the inside of each of the inner tubes 109 and 110
07 is installed, and a pump 105 is provided outside the core tube 101.
Is provided. Then, the gas supplied from the gas introduction pipe 107 passes between the inner inner pipe 110 and the outer inner pipe 109 and the core tube 101 and is exhausted by the pump 105.

Meanwhile, in such a vertical furnace, the gas concentration and the temperature in the wafer surface in the batch are made uniform while the degree of vacuum is kept constant. It becomes constant and leads to improvement of film thickness and film quality. In the vertical diffusion furnace, the diffusion speed is constant, and the diffusion concentration and the range are uniform. Therefore,
Also in the vertical furnace according to the present embodiment, the inner tubes 9 and 1 are inserted inside the core tube 101 similarly to the conventional example shown in FIGS.
0 is provided to control the gas flow, and the boat 4 is provided with a rotation mechanism to rotate each semiconductor wafer 103 so that the degree of vacuum, gas concentration and temperature in the wafer surface of the wafers in the batch are kept uniform. Have been devised. That is, the gas introduction pipe 107 is provided between the wafer 103 and the inner inner pipe 110 and between the inner inner pipe 110 and the outer inner pipe 109 in order to make the gas concentration in the furnace uniform and to make the formed film uniform.
And the gas is supplied.
Further, in order to make the film thickness distribution in the wafer plane uniform, the boat 104 has a rotating structure.
Are simultaneously rotated.

However, in spite of such a contrivance, the temperature distribution and the gas concentration distribution in the furnace have a certain variation in the vertical direction in the furnace as shown in FIGS. As a result, the film thickness distribution in the batch also
As shown in the figure, several percent variation occurs. In particular, the lower part of the boat 104 near the gas introduction part (introduction pipe 107),
In addition, the upper portion close to the gas exhaust side (the pump 5 side) is not stable, and there are places where the predetermined film thickness standard is not met. In this area, dummy wafers are loaded, and official wafers are placed only in the stable central part and produced. In addition, as shown in FIG. 8, the film thickness distribution in each wafer surface also tends to be easily formed on the outer peripheral portion. Particularly when a thick film is formed, this tendency becomes remarkable.
In some cases, the production is performed by widening the gap between the wafers so that the gas enters smoothly.

Therefore, in the vertical furnace according to the present embodiment,
In order to reduce these problems, in the conventional vertical furnace, each wafer 3 is held horizontally on the boat 4,
As shown in FIG. 1 and FIG.
A is provided with a groove shape capable of holding each wafer 103 in an inclined manner, so that each wafer 103 set in the groove is arranged at a predetermined angle with respect to the rotary drive shaft. Things. Therefore, if the boat 104 rotates as before, the wafer 103 held at an angle rotates and the gas between the wafer 103 and the inner inner tube 110 and the outer inner tube 109 is agitated. Then, the gas concentration distribution in the lower part also becomes uniform.

Further, since the temperature in the furnace is transmitted by radiant heat, a time difference occurs depending on the distance and the gas concentration to make the temperature uniform, but the time is shortened by stirring with the inclined wafer, and The internal temperature distribution becomes uniform. In addition, since a flow is generated in the gap between the wafers 103, gas enters better. As a result, variations in the film thickness distribution between wafers in each batch and the film thickness distribution in one wafer surface can be reduced by half, and the film thickness can be made uniform and the film quality can be improved. Note that a sufficient effect can be obtained if the inclination angle の of the wafer 103 is, for example, about 5 ° to 10 °.

In the embodiment of the present invention described above, the following effects can be obtained. (1) The uniformity of the film thickness between the wafers in the batch and on each wafer surface and the improvement of the film quality can improve the reliability of products and stably operate the apparatus. (2) By making the film thickness distribution uniform between wafers in a batch, the production use range in the furnace is widened, and productivity can be improved. Further, the required number of loaded dummy wafers can be reduced. (3) Variation in film thickness distribution and film quality in the wafer plane is reduced, so that the number of usable chips in the wafer plane increases. (4) When the wafer is held obliquely by the support of the boat, the wafer is mounted in the groove of the support with the edge on the support side of the wafer inclined downward, and the edge of the wafer without the support is upward. It will be placed, compared to the case where it is placed horizontally, the wafer will not drop from the boat,
Damage (cracks, etc.) of the wafer due to falling can be reduced.

Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 4, in order to further improve the effect of stirring the gas in the furnace tube,
A plurality of (two in the illustrated example) fins 112 for gas stirring are provided on a support 104A of a boat 104. As shown, each fin 112 is attached to the semiconductor wafer 103.
Are provided on the column 104A so as to extend in the outer diameter direction of the fin 112. The base end 112A of each fin 112 is
A and attached to the outer surface of
12B is provided in a state of being disposed in front of the rotation direction of the semiconductor wafer 103 (arrow A in the figure). Also,
Each fin 112 is arranged in the height direction of the support 104A.
They have the same shape.

By providing such fins 112, the gas between the semiconductor wafer 103 and the inner inner tube 110 and the outer inner tube 109 is stirred, and a gas flow is generated in the gap between the semiconductor wafers 103. It is possible to further improve the gas entry. The other configuration is the same as that of the first embodiment, and the same reference numerals are given and the description is omitted. In addition, such a fin 112
May be applied to the conventional vertical furnace shown in FIGS. 9 and 10. The number and shape of the fins 112 are as follows:
The shape is not limited to the above example, and may be, for example, a shape having a certain change between the upper part, the middle part, and the lower part in the furnace.

[0022]

As described above, in the vertical furnace of the semiconductor manufacturing apparatus according to the present invention, the boat that holds and rotates a large number of semiconductor wafers rotates each semiconductor wafer by a predetermined angle with respect to the rotary drive shaft. The semiconductor wafer was held in an inclined state, and the gas in the furnace tube was stirred by the rotation of each semiconductor wafer. Therefore, each semiconductor wafer in the batch,
In addition, uniform processing can be performed on the front surface within one semiconductor wafer, a semiconductor having uniform characteristics can be manufactured, and quality can be improved and production efficiency can be improved.

In the vertical furnace of the semiconductor manufacturing apparatus according to the present invention, fins for stirring the gas in the core tube are provided on the column of the boat that rotates while holding a large number of semiconductor wafers. The gas in the tube was agitated. Therefore, uniform processing can be performed on each semiconductor wafer in the batch and on the front surface in one semiconductor wafer, and a semiconductor with uniform characteristics can be manufactured, thereby improving quality and improving production efficiency. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a vertical furnace of a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a side view showing an appearance of a boat used in the vertical furnace shown in FIG.

FIG. 3 is a plan view showing a state of holding a semiconductor wafer by a boat shown in FIG. 2;

FIG. 4 is a plan view showing a state of holding a semiconductor wafer by a boat according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing an example of a temperature distribution in a conventional vertical furnace.

FIG. 6 is an explanatory diagram showing an example of a gas concentration distribution in a conventional vertical furnace.

FIG. 7 is an explanatory diagram showing an example of a conventional film thickness distribution generated between wafers in a batch.

FIG. 8 is an explanatory view showing an example of a conventional film thickness distribution generated on one wafer surface.

FIG. 9 is a sectional view showing a structural example of a conventional vertical furnace.

FIG. 10 is a side view showing the appearance of a boat used in the vertical furnace shown in FIG.

[Explanation of symbols]

101: core tube, 102: heater, 103: semiconductor wafer, 104: boat, 104A: support, 1
05 ... pump, 106 ... hatch, 107 ... gas introduction pipe, 109 ... outer inner pipe, 110 ... inner inner pipe, 11
2 ... fins.

Claims (10)

[Claims] 1. A semiconductor comprising: a core tube for performing various operations on semiconductor wafers; and a boat housed in the core tube and rotatably driving a plurality of semiconductor wafers at predetermined intervals in a plate thickness direction. In the vertical furnace of the manufacturing apparatus, the boat holds each semiconductor wafer in a state of being inclined by a predetermined angle with respect to the rotary drive shaft, so that the gas in the furnace tube is stirred by the rotation of each semiconductor wafer, A vertical furnace for a semiconductor manufacturing apparatus, comprising: 2. The boat according to claim 1, wherein the boat has a plurality of columns for engaging and holding an outer peripheral portion of the semiconductor wafer, and each of the columns holds each semiconductor wafer at a predetermined angle. Item 4. A vertical furnace for a semiconductor manufacturing apparatus according to Item 1. 3. A vertical furnace for a semiconductor manufacturing apparatus according to claim 2, wherein fins for stirring gas in a furnace core tube are provided on said column. 4. The fin is provided so as to extend in an outer diameter direction of the semiconductor wafer, and is provided in a state where a tip portion of the fin is disposed in front of a rotation direction of the semiconductor wafer. 4. The vertical furnace of a semiconductor manufacturing apparatus according to claim 3, wherein: 5. CVD of a semiconductor wafer in the furnace tube
2. The vertical furnace for a semiconductor manufacturing apparatus according to claim 1, wherein the operation is performed. 6. The vertical furnace for a semiconductor manufacturing apparatus according to claim 1, wherein a semiconductor wafer is thermally diffused in said furnace tube. 7. A semiconductor having a furnace tube for performing various operations on semiconductor wafers, and a boat housed in the furnace tube and rotatably driving a plurality of semiconductor wafers at predetermined intervals in a plate thickness direction. In the vertical furnace of the manufacturing apparatus, the boat has a plurality of columns for engaging and holding an outer peripheral portion of a semiconductor wafer, and the columns are provided with fins for stirring gas in a furnace tube. Vertical furnace for semiconductor manufacturing equipment. 8. The fin is provided so as to extend in an outer radial direction of the semiconductor wafer, and is provided in a state where a tip portion of the fin is disposed in front of a rotation direction of the semiconductor wafer. The vertical furnace of a semiconductor manufacturing apparatus according to claim 7, wherein: 9. CVD of a semiconductor wafer in said furnace tube
8. The vertical furnace for a semiconductor manufacturing apparatus according to claim 7, wherein the operation is performed. 10. The vertical furnace for a semiconductor manufacturing apparatus according to claim 7, wherein a semiconductor wafer is thermally diffused in said furnace tube.