JPH0528488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to processing technology, and in particular to technology for loading and unloading workpieces into and out of process tubes using soft landing type boat loaders. The present invention relates to a technique that is effective for use in the process of diffusing impurities such as.

[Background technology]

In the manufacturing of semiconductor devices, a diffusion device is used to diffuse impurities into wafers. Multiple wafers are held in a jig called a boat, and this boat is placed on a fork so that it does not come into contact with the process tube. Some products are configured to prevent dust generation by conveying the material by using a soft landing (so-called soft landing).

However, in such a diffusion device, when performing phosphorus diffusion treatment, the reaction product causes the boat to adhere to the process tube.
In addition, the inventors have discovered that there is a problem in that the treatment temperature is high and the forks tend to bend, so they cannot be used for phosphorus diffusion treatment.

An example of a diffusion technique that describes the diffusion technology is "Electronic Materials November 1984 Special Edition" published by Kogyo Research Association Co., Ltd., November 20, 1984, pages 57 to 61.

Furthermore, in heat treatment technology for semiconductor wafers,
The technology to prevent reaction products from welding the boat, which is a jig, to the process tube was disclosed in Japanese Patent Application Laid-Open No. 1986-
It is disclosed in Publication No. 62489.

However, the technology disclosed in this publication is proposed solely for the purpose of preventing the jig and the process tube from being welded or bonded by reaction products, and for that purpose, the former is forked and the latter is These conventional techniques are configured so that the object to be processed (a quartz pipe) can be moved up and down or oscillated, and these conventional techniques move the jig welded with reaction products through heat treatment to the process tube during pick-up after welding. The purpose is not to peel it off from the body, and of course it is not designed for that purpose.

[Purpose of the invention]

An object of the present invention is to provide a processing technique that allows a jig that has been landed and welded in a processing chamber to be peeled off from the processing chamber and to use a soft landing type boat loader.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the invention]

An overview of typical inventions disclosed in this application is as follows.

The present invention provides a processing chamber equipped with a process tube for heat-treating a plurality of semiconductor wafers, a boat that holds the plurality of wafers, and a fork that supports the boat and takes it in and out of the process tube of the processing chamber. A processing device comprising a soft landing type boat loader comprising:
The fork is provided with a peeling device that peels off the boat from the welded state with the process tube when the boat landed in the process tube of the processing chamber is picked up by the fork, and the peeling device , motor and
A camshaft is disposed substantially parallel to the center line of the fork and is directly connected to the motor shaft and rotatably supported. The present invention is characterized in that it includes a cam that engages with the lower surface of one side of the boat, and by rotating and raising the cam, only the one side of the boat is lifted and the boat is separated from the processing chamber.

〔Example〕

FIG. 1 is a longitudinal sectional view showing a diffusion device which is an embodiment of the present invention, FIGS. 2, 3 and 4 are longitudinal sectional views for explaining its operation, and FIGS. The figure is also an enlarged partial cross-sectional view with some parts omitted.
Similarly, FIGS. 8 and 9 are diagrams.

In this embodiment, this diffusion device includes a process tube 1 formed of quartz glass or the like into a substantially cylindrical shape.
The internal chamber substantially forms the processing chamber 2 . A heater 3 is installed outside the process tube 1, and the heater 3 is configured to heat the process chamber 2 under control of a controller (not shown). A supply port 4 for introducing a processing gas such as phosphorus, boron, oxygen, nitrogen, etc. is provided at one end of the process tube 1, and a wafer as a workpiece is provided at the other end of the process tube 1. 6
A furnace opening 5 is provided as an opening for taking in and taking out. A plurality of wafers 6 are held in a boat 7 that is assembled using quartz glass or the like, and are arranged in parallel to each other and erected substantially vertically.

In front of the process tube 1 is a soft landing type boat loader 10 (hereinafter referred to as the loader).
This loader 10 is equipped with a lifting mechanism 1.
1, a guide stand 12 that is raised and lowered substantially horizontally by an elevating mechanism, and is configured to be slidably supported by the guide stand in the front and back direction and driven by an appropriate drive device (not shown). The fork 14 is provided with a movable base 13 and a fork 14 supported in a cantilever manner by the movable base. The fork 14 is formed of quartz glass or the like into a substantially cylindrical shape with a diameter smaller than that of the process tube 1. At the tip of the fork 14, a holding portion 15 formed by cutting off the upper side of the cylinder holds the wafer 6. It is formed so that it can support the boat 7 placed thereon.

The fork 14 is equipped with a peeling device 16 for slightly moving and peeling off the boat 7 adhered to the bottom surface of the process tube 1 by the reaction product.
The peeling device 16 has a motor 1 as an actuator.
7, a camshaft 18 arranged substantially parallel to the center line of the fork 14 and rotatably supported while being connected to a motor shaft, and an engaging portion 7c at the front end of the boat 7 at the tip of the camshaft. a cam 19 arranged and fixed so as to be able to engage with the fork 14; and a pair of left and right legs fixed approximately vertically to the left and right sides of the cam shaft 18 in the middle of the fork 14 to prevent the cam shaft from wobbling laterally. It is composed of a pillar 20.

Next, the action will be explained.

As shown in FIG. 1, the boat 7 holding a plurality of wafers 6 as objects to be processed has a holding portion formed at the tip thereof when the fork 14 is pulled out from the process tube 1. 15.

When the boat 7 is placed, the fork 14 is inserted into the processing chamber 2 from the furnace opening 5 of the process tube 1 as the moving table 13 moves forward. At this time,
As shown in FIG. 2, the fork 14 is inserted and moved so that its lower surface does not contact the bottom surface of the processing chamber 2, so that the reaction products deposited on the bottom surface of the processing chamber 2 are peeled off. No dust will be generated by doing this.

When the boat 7 on the holding part 15 reaches a predetermined position in the approximate center of the processing chamber 2, the insertion movement of the fork 14 is stopped and the lifting mechanism 11 lowers the boat 7 slightly. It is transferred onto the bottom of the inside. Subsequently, the fork 14 is pulled out from the furnace opening 5 of the process tube 1 to the outside of the processing chamber 2 as the moving table 13 retreats.

Thereafter, as shown in FIG. 3, when the furnace port 5 of the process tube 1 is closed by the cap 8 and the processing chamber 2 is heated to a predetermined temperature, a processing gas such as phosphorus is supplied. It is introduced into the processing chamber 2 through the port 4. The introduced processing gas contacts the group of 6 wafers held in the boat 7 to perform a predetermined diffusion process.

When the predetermined process is completed, the fork 14 is inserted into the process tube 1 through the furnace mouth 5, which is opened by removing the cap 8, by moving the moving table 13 forward. At this time, the fork 14 is inserted directly under the boat 7 so as not to contact the bottom surface of the processing chamber 2 of the process tube 1, and the cam 19 in the peeling device 16 is inserted into the boat 7 as shown in FIG. It is arranged so as to face the lower surface of the engaging portion 7c protruding from the front end.

Next, when the motor 17 is activated and the cam 19 is erected via the camshaft 18 as shown in FIG. 6, the boat 7 is moved by the cam 19 as shown in FIG. Then, the engaging portion 7c at the front end can be lifted up. Once lifted, the boat 7 is returned to its original horizontal transfer state as the cam 19 is lowered.

When the boat 7 is returned to its original position, the fork 14 is raised slightly and then pulled out from the furnace mouth 5 of the process tube 1 as the moving table 13 retreats.
At this time, as in the above case, since soft landing is performed, dust generation is prevented.

Thereafter, the boat 7 is lowered from the holding part 15 of the fork 14 outside the process tube 1.

By the way, when phosphorus is used as the processing gas, if the boat is supported on the bottom of the processing chamber, reaction products will adhere to the contact area between the boat and the bottom of the processing chamber, causing the two to adhere. Otherwise, it will be welded. Then, it becomes difficult to scoop up the bonded boat with the fork of a soft landing type boat loader, and if it is lifted forcibly, the fork may bend due to the adhesive force and the high temperature of the phosphorous treatment, and damage the boat and process tube. may occur.

For this reason, it is considered inappropriate to use a soft-landing type boat loader in processes where reactants are generated, such as phosphorus diffusion treatment, or in high-temperature processes.

However, in this embodiment, the use of a soft landing type boat loader is realized by moving the glued boat and then scooping it up with a fork.

That is, when the boat 7 is carried out from the processing chamber 2 of the process tube 1 by the fork 14, when one side of the boat 7 is lifted by the cam 19, the leg 7a of the boat 7 on the lifted side
is peeled off from the bottom of the processing chamber 2. At this time, since only one side of the boat is lifted, the bonded portion caused by the reaction product is easily peeled off.

On the other hand, the legs 7b remain seated on the bottom of the processing chamber 2.
In this case, since the boat 7 moves slightly when it is tilted by being lifted on one side, the adhesion caused by the reaction product here is also easily peeled off.

In this way, the boat 7 is lifted and moved on one side, thereby moving the process tube 1
Since the boat 7 is peeled off from the bottom of the processing chamber 2 in advance, the boat 7 can be easily scooped up by the fork 14.

By the way, Fig. 7, Fig. 8, and Fig. 9 are diagrams showing the temperature change over time in the process tube. When a soft landing type boat loader is used, FIG. 9 shows a case where the soft landing type boat loader according to this embodiment is used and the heating control of the heater is modified. In the figure, the solid line indicates The broken line indicates the temperature change at the center, and the chain line indicates the temperature change at the back of the furnace.

As is clear from the comparison between FIG. 7 and FIG. 8, when a soft landing type boat loader is used, the temperature change is larger than when a sliding type boat loader is used.

Therefore, in this embodiment, a heating control pattern for the heater 3 is determined based on the temperature change in the soft landing type boat loader, and the temperature change is suppressed as much as possible as shown in FIG. That is, by setting the time from when the fork 14 starts and the heating capacity of the heater 3, the temperature drop due to the increase in heat capacity due to insertion of the fork 14 into the process tube 1 is compensated for, and the recovery time is shortened. Control temperature changes within the process tube 1.

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 described above, and it is understood that various changes can be made without departing from the gist of the invention. Needless to say.

〔effect〕

(1) The fork is equipped with a peeling device that peels off the wafer holding boat landed in the processing chamber from the welded state with the process tube when the fork picks up the boat. The boat is equipped with a cam that engages with the lower side of one side of the boat, and when the cam is turned up, only one side of the boat is lifted and the boat is separated from the process tube, making it possible to pick up the boat with a fork. Since the welded portion between the boat and the process tube is peeled off beforehand, the soft landing type boat loader can be used even under conditions where the boat is adhered to the process tube by reaction products.

(2) By using a soft landing type boat loader, it is possible to prevent dust generation during the loading and unloading of objects to be processed, thereby improving yield and promoting automation.

(3) By installing a peeling device on the fork, there is no need for a person to open the furnace mouth and apply an impact to the boat to peel off the bonded parts of the boat, reducing the number of work steps and improving throughput. It also improves work safety by eliminating dangerous work under high heat, and prevents adverse effects such as damage to boats and process tubes due to impact. can be avoided.

(4) the stripping device includes a cam that engages the underside of one side of the boat on the mouth side of the process tube;
By rotating this cam, only one side of the boat is lifted and the boat is separated from the process tube, so if one side of the boat is lifted, the other side becomes a fulcrum, so the force required to separate the boat is can be made smaller, the boat can be easily separated, deformation stress can be suppressed from being applied to the fork, and the boat lifting mechanism can be made into a simple structure, making it possible to reduce the size and weight of the device.

(5) By controlling the heating of the heater to suppress temperature changes caused by the use of a soft landing type boat loader, the soft landing type boat loader can also be used in diffusion processes where temperature accuracy and temperature recovery time are restricted. I can do it.

[Application field]

In the above explanation, the invention made by the present inventor was mainly applied to a diffusion device, which is the background field of application. It can be applied to other processing devices in general.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing a diffusion device to which a soft landing type boat loader is applied, which is an embodiment of the present invention, and Figs. 2, 3, and 4 are longitudinal cross-sections for explaining the operation. Figures 5 and 6 are enlarged partial cross-sectional views with some parts omitted;
Similarly, FIGS. 8 and 9 are diagrams. 1...Process tube, 2...Processing chamber, 3...Heater, 4...Gas supply port, 5...Furnace opening, 6...Wafer (workpiece), 7...Boat (jig), 8...Cap, 1
0...Soft landing type boat loader, 11...
Lifting mechanism, 12... Guide stand, 13... Moving stand, 14
...Fork, 15... Holding part, 16... Peeling device, 1
7...Motor (actuator), 18...Camshaft,
19...cam, 20...post.

Claims (1)

[Claims] 1. A processing chamber comprising a process tube for heat-treating a plurality of semiconductor wafers, a boat for holding a plurality of semiconductor wafers, and a fork for supporting the boat and moving it in and out of the process tube of the processing chamber. A processing apparatus comprising a soft landing type boat loader, wherein the boat is welded to the process tube when the fork picks up the boat that has been landed in the process tube of the processing chamber. A peeling device is provided for peeling from the fork, and the peeling device includes a motor and a cam shaft arranged substantially parallel to the center line of the fork and directly connected to the motor shaft and rotatably supported. and a cam formed at the tip of the camshaft to engage with the lower surface of one side of the boat on the furnace mouth side of the process tube, and by rotating and raising the cam, only the one side of the boat can be moved. A processing apparatus characterized in that the boat is lifted and separated from the processing chamber.