JPH01187812A - Semiconductor processing jig - Google Patents

Abstract

PURPOSE:To prevent the bottom of a reaction tube from being brought into contact with a pedestal and to facilitate the removal, replacement of the pedestal by so bringing the part of legs 1 of the pedestal into noncontact with the bottom of the tube that the bottom is separated from a pedestal body near the port of the tube. CONSTITUTION:A pedestal 10 is inserted from a port 5 into the processing chamber 2 of a reaction tube 1, and placed on the bottom of the chamber 2. The pedestal 10 covers the bottom of the chamber 2 corresponding to a wafer mounting position from the vicinity of the port 5 substantially in contact with a cap 9 and slightly floats from the bottom by legs 11. In this case, the legs 11 are isolated from the bottom of the tube 1 in the vicinity 12 of an inlet in which reaction product tends to be mostly accumulated. A boat 7 is conveyed from the port 5 of the tube 1, and slid on the pedestal 10 to be set to a predetermined position of the chamber. Thereafter, the chamber 2 is heated by a heater 3 to a predetermined temperature, impurity gas generated from a diffusion impurity source disposed on an impurity holder 8 is brought into contact with wafer 6 group held on the boat to be diffused as predetermined.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to heat treatment technology, special feature K, and countermeasures for reducing contamination in reaction tubes for semiconductor heat treatment. The present invention relates to a semiconductor processing jig that can be effectively utilized.

[Conventional technology]

In the manufacture of semiconductor devices, a method of depositing boron to form a P-type impurity diffusion layer on semiconductor wafers involves placing multiple wafers (silicon) on a quartz boat and storing them together with a deposition agent in a quartz reaction tube. There is a technique in which deposition is performed by sealing the inside of a reaction tube under reduced pressure and then forming an impurity atmosphere while performing heat treatment.

In addition, as a device for depositing phosphorus for n-type impurity diffusion onto semiconductor wafers, multiple wafers are placed on a boat and housed in a reaction tube, and phosphorus oxychloride (
poct, ).

In these diffusion devices, reaction products accumulate and adhere to the relatively low-temperature part of the furnace opening of the reaction tube, so when a boat holding wafers is moved in and out of the reaction tube, the wafers are scattered due to the adhered substances. There is a problem that it becomes contaminated. For this reason, there is a technique in which a removable pedestal is disposed within the reaction tube and is replaced depending on the degree of adhesion of reaction products.

Incidentally, regarding this type of diffusion technology, there is, for example, Japanese Patent Publication No. 49-124967.

[Problem to be solved by the invention]

In the above-mentioned conventional technology, there was a problem in that the bottom of the reaction tube and the pedestal installed inside the tube stuck to each other due to the reaction products accumulated in the relatively low-temperature part of the furnace mouth of the reaction tube, making it difficult to remove the pedestal. .

An object of the present invention is to prevent the reaction tube bottom and the pedestal from sticking together, and to facilitate the removal and replacement of the pedestal.

[Means to solve the problem]

The above object is achieved by making a part of the legs of the pedestal non-contact with the bottom of the reaction tube so that the bottom surface and the pedestal body are separated from each other near the furnace mouth of the reaction tube.

[Effect]

According to the above-mentioned means, it is possible to avoid adhesion of the pedestal to the part where the reaction products in the quartz tube accumulate the most, so that the jig can be easily taken out and replaced, and the above object can be achieved.

〔Example〕

FIG. 1 is a longitudinal cross-sectional view showing a diffusion device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a perspective view showing the base thereof.

In this embodiment, this diffusion device includes a reaction tube 1 formed in a cylindrical shape from quartz glass or the like, and the inside of this reaction tube 1 serves as a processing chamber 2. A heater 3 is installed 4 outside the reaction tube 1, and the heater 3 is configured to heat the processing chamber 2 under control of a control device (not shown). A supply port 4 for introducing an atmospheric gas such as oxygen or nitrogen is provided at one end of the reaction tube.

, this supply port 4 is also connected to a vacuum device (not shown) for reducing the pressure in the processing chamber 2 . At the other end of the reaction tube 1, a furnace port 5 is opened, through which a wafer 6 as an object to be processed is taken in and taken out. A plurality of wafers 6 are made of quartz glass or the like, and are held in a boat 7 having grooves, arranged parallel to each other and erected substantially vertically. A cylindrical impurity holder 8 is placed around the wafer 6 in which a diffused impurity source (not shown) is placed. A cap 9 capable of closing the reaction tube 1 is detachably installed at the furnace mouth 5.

A pedestal 10 shown in FIG. 3 is inserted into the reaction tube 1 and placed on the bottom surface thereof. The pedestal 10 is made of the material forming the reaction tube 1, such as quartz glass, and is made of a circular tube that is approximately 1/4 of the diameter of the reaction tube 1.
The pedestal (1/3) is cut vertically to approximately 1/3 to form a circular arc cross section, and its length is set so that it can cover the area from the furnace opening 5 of the processing chamber 2 to the wafer installation location. body)
A plurality of legs 11 are attached to the bottom surface of the pedestal 10 to connect the pedestal]O to the processing chamber 2.
It is designed to protrude from the bottom so that it can be floated. The legs 11 are made of a round rod made of the material used to form the reaction tube 1, such as quartz glass, arranged parallel to the center line and fixed to the bottom of the pedestal. The leg portions 11 have a structure that allows them to be easily separated from the bottom surface of the reaction tube at a portion where reaction products caused by impurity gases tend to accumulate, for example, near the furnace mouth portion 12.

Next, usage modes and effects will be explained.

The pedestal 10 is inserted into the processing chamber 2 of the reaction tube 1 from the furnace mouth 5 and placed on the bottom surface of the processing chamber 2. In this mounted state, the pedestal 10 covers the bottom part of the processing chamber 2 corresponding to the wafer installation location from the vicinity of the furnace opening 5, which is almost in contact with the cap 9, and is slightly raised from the bottom surface by the legs 11. At this time, the legs 11 are separated from the bottom surface of the reaction tube 1 near the inlet 12 where reaction products are most likely to accumulate.

A boat 7 holding a plurality of semiconductor wafers 6 as objects to be processed is carried in from the furnace opening 5 of the reaction tube, and is slid on a pedestal 10 and set at a predetermined position in the processing chamber 2.

Thereafter, the furnace opening 5 of the reaction tube 1 is closed with a cap 9, the processing chamber 2 is heated to a predetermined temperature by the heater 3, and the impurity gas generated from the diffused impurity source placed in the impurity holder 8 is transferred to the board. A predetermined diffusion process is performed by bringing the wafer into contact with a group of 6 wafers held in the wafer.

After the treatment, the boat 7 is pulled out from the furnace opening 5 of the reaction tube 1 while sliding on the pedestal 10 by hooking the pull-out rod.

During the above processing, reaction products tend to adhere and accumulate on the surfaces of the processing chamber 2 and the pedestal 10. When the boat slides over the deposits, the deposits are peeled off and scattered, resulting in contamination of the wafers due to their adhesion to the wafers. Therefore, in order to suppress the accumulation of reaction products, the pedestal 10
need to be washed frequently. That is, since the reaction tube 1 is large and heavy, its cleaning work is difficult and reduces work efficiency. In this invention, the pedestal 2 seat 10 is the reaction tube 1.
The boat 7 is set in a removable manner on the bottom of the processing chamber, and the boat 7 is slid onto this pedestal 10. By frequently replacing and cleaning the pedestal 10, contamination of the wafers 6 is prevented. be done.

When cleaning the pedestal 10, first, a boat pull-out rod is inserted through the furnace mouth 5, hooked into the small hole 13 on the front side of the pedestal 10, and the pedestal 10 is pulled out from the reaction tube 1.

At this time, in this embodiment, the legs 11 of the pedestal are spaced apart from most of the bottom surface of the reaction tube 1 in the vicinity 12 of the furnace inlet where the reaction products in the processing chamber 2 are most likely to accumulate. It can be easily separated from 1.

Subsequently, another pedestal 10, which has already been cleaned, is inserted into the reaction tube 10 at a predetermined position through the furnace mouth 5. After that, the above-mentioned diffusion process cannot be performed.

The pedestal 10 that has not been removed from the reaction tube 1 is cleaned by a suitable method such as wet etching and reused.

The following effects can be obtained from the above embodiment.

(1) By separating the legs of the pedestal set on the bottom of the reaction tube from the bottom of the reaction tube near the inlet of the reaction tube where reaction products are most likely to accumulate, it is possible to prevent the pedestal from sticking to the bottom of the reaction tube. It becomes easy to take out and replace the wafer, and it is possible to effectively reduce foreign matter adhering to the wafer due to foreign matter scattering due to boat sliding.

(2) Since the contact area between the legs of the pedestal and the bottom of the reaction tube is kept to the minimum necessary, the adhesion between the bottom of the reaction tube and the pedestal is
- This can be prevented and the effect of (1) above can be increased.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Not even.

For example, the legs of the pedestal are not limited to quartz glass round rods, but can also be made of square rods with their edges touching the bottom of the reaction tube, thereby reducing the area of contact with the bottom of the reaction tube. The above embodiment can also be made more effective.

In the above explanation, we have mainly explained the case where the invention made by the present inventor is applied to a diffusion device, which is the background field of application, but is not limited to this, and is applicable to a low pressure CVD device and other devices. It can be applied to processing equipment in general.

〔Effect of the invention〕

According to the present invention, a part of the leg of the pedestal set on the bottom surface of the reaction tube is separated from the bottom surface of the reaction tube.
Since the pedestal can be easily attached and detached and can be washed frequently, it is possible to prevent contamination of the object to be processed due to scattering of deposits when taking out and taking out the object.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a diffusion device which is an embodiment of the present invention. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. FIG. 3 is a perspective view showing the pedestal portion. 1... Reaction tube, 2... Processing chamber, 3... Heater, 4
... Gas supply port, 5... Furnace opening, 6... Wafer (workpiece), 7... Hoard (jig), 8... BN jig, 9... Camp, work 0...Pedestal, 11...Legs,
12... Entrance, 13... Small hole. Agent Patent Attorney Katsuo Ogawa -6,'Fig. Figure 3

Claims (1)

[Scope of Claims] 1. A pedestal for semiconductor heat treatment installed in a reaction tube, which includes a pedestal main body having an arc-shaped cross section, and a plurality of places on the bottom of the pedestal main body, which are provided at a plurality of places on the bottom of the pedestal main body, and have a minimum distance from the bottom surface of the reaction tube. 1. A semiconductor processing jig, comprising a leg portion having a shape that makes contact in area. 2. The semiconductor processing jig according to claim 1, wherein the leg portions are a plurality of rod-shaped bodies made of quartz.