JPH02106923A - Heat treating method for substrate - Google Patents

Abstract

PURPOSE:To reduce a mounting area and the cost of an apparatus by providing one substrate transfer mechanism for a plurality of reactor bodies, and transferring a substrate to be treated in other reactor body when it is treated in one reactor body. CONSTITUTION:When the transfer of a substrate by a transfer mechanism 8 is finished, a wafer boat 3a is conveyed by a conveying mechanism 9 to be placed on a boat elevator 5a. The mechanism 9 in which the conveyance of the boat 3a is finished at the side of a reactor body 2a is moved to the body 2a side, and the board 3a is moved to a predetermined transfer position. A dummy wafer and a semiconductor wafer 4 are transferred one by one from wafer cassettes 6c, 6d to the board 3b of the body 2b by the mechanism 8, the board 3b is conveyed onto a board elevator 5b by the mechanism 9 after the transfer is finished, and a waiting state is set until the end of the process in the body 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for heat treating a substrate using a vertical heat treatment apparatus.

(Conventional technology) In recent years, heat treatment equipment used in the film formation process and thermal diffusion process in the semiconductor device manufacturing process has been developed to save space, save energy, increase the diameter of semiconductor wafers to be processed, and increase automation. Vertical heat treatment equipment has been developed for reasons such as ease of handling.

Such a vertical heat treatment apparatus is equipped with a cylindrical reaction vessel made of quartz or the like and surrounding the vessel.
The main body of the reactor, which consists of a heat sink, soaking tube, heat insulating material, etc., is arranged almost vertically, and a wafer boat made of quartz, etc., in which a large number of semiconductor wafers are stacked on shelves at predetermined intervals, is placed inside the reaction vessel. has been done. This wafer boat is configured so that it can be loaded and unloaded from below into a reaction vessel by a lifting mechanism, and a desired heat treatment can be performed on a large number of semiconductor wafers.

Further, when transporting semiconductor wafers, a transport substrate holder made of resin, a so-called wafer cassette, is usually used.

Therefore, it is necessary to transfer the semiconductor wafer from this wafer cassette to a wafer boat (substrate holder for processing).
One transfer mechanism is installed in each reactor body.

(Issue 8 to be solved by the invention) By the way, in such a vertical heat treatment apparatus, in order to shorten the loading time of the substrate to be processed, it is usually not necessary to transfer the substrate to be processed from the wafer cassette to the wafer boat. It is done in batch mode. However, with this batch-type substrate transfer mechanism, it is difficult to cope with larger diameter semiconductor wafers, so a single-wafer transfer mechanism for substrates to be processed is desired. There is a problem in that simply using a single-wafer transfer mechanism reduces processing efficiency. Further, in such a vertical heat treatment apparatus as well, it is naturally required to further reduce the installation area and reduce the apparatus cost.

The present invention has been made in response to such conventional circumstances, and makes it possible to reduce the installation area and equipment cost in a vertical heat treatment apparatus compared to the conventional one, and also reduces production efficiency. The purpose of the present invention is to provide a method for heat treatment of substrates that makes it possible to transfer substrates to be processed in a single wafer manner.

[Structure of the Invention] (Means for Solving the Problems) In other words, the substrate heat treatment method of the present invention includes the following steps when performing a desired heat treatment on a substrate to be processed in each of a plurality of reactor bodies provided substantially vertically. During the period when the heat treatment is performed in the first reactor main body, the substrate transfer mechanism provided between the plurality of reactor main bodies holds the substrate for transportation on the processing substrate holder in the second reactor main body. The method is characterized in that the substrates to be processed are transferred one by one from the reactor, and the heat treatment and the transfer of the substrates to be processed are sequentially performed on the plurality of reactor bodies, and the processing is continuously repeated.

(Function) One substrate transfer mechanism is provided for multiple reactor bodies,
By transferring the substrate to be processed from one reactor main body to another while processing is being performed in one reactor main body, the substrate transfer mechanism can be shared among multiple reactor main bodies, increasing the overall operating rate of the equipment. In addition, it is possible to compensate for the decrease in processing efficiency due to single-wafer transfer of substrates in the entire apparatus.

(Example) Hereinafter, a vertical heat treatment apparatus to which the substrate heat treatment method of the present invention is applied will be described with reference to the drawings.

The housing 1 includes, for example, three housings 1a, 1b, and an IC, which are connected horizontally along the boundary of a clean room. Among these casings 1a to IC, casings 1a11C provided on both sides each contain a cylindrical reaction vessel made of, for example, quartz, a resistance heater, a soaking tube, Two reactor bodies 2a and 2b made of a heat insulating material and the like are arranged substantially vertically. In addition, these reactor main bodies 2a
, 2b, a large number of semiconductor wafers 4 placed on wafer boats 3a, 3b are loaded and unloaded into the reactor bodies 2a, 2b. As a mechanism for
, 5b are provided, respectively.

Further, in the case 1b provided in the center among the cases 1a to IC, there is a wafer cassette accommodating part 7 in which a plurality of transport substrate holders, for example, four wafer cassettes 68 to 6d can be placed. It is provided. And this case 1
Inside b, there is a transfer mechanism 8 for transferring the semiconductor wafers 4 from the cassettes 6a to 6d to the wafer boats 3a and 3b, and a wafer boat 3 to which the semiconductor wafers 14 are transferred by the transfer mechanism 8. A transport mechanism 9 is provided to transport the a s 3 b and place it on the boat elevators 5a, 5b.

The heat treatment of the semiconductor wafer 4 in the vertical heat treatment apparatus of this embodiment having the above configuration is performed, for example, in accordance with the procedure shown below.

For example, as shown in FIG.
6d is arranged perpendicularly to the wafer cassette accommodating section 7 (FIG. 1-A). Among these cassettes 6a to 6d, for example, the wafer cassette 6a accommodates processing wafers for the reactor main body 2a, the wafer cassette 6b accommodates dummy wafers for the reactor main body 2a, and the cassette 6d accommodates processing wafers for the reactor main body 2b. The wafers for processing are placed in the wafer cassette 6c in the reactor main body 2b.
Dummy wafers for use are stored. Next, after aligning the orientation flats to the semiconductor wafers 4 housed in these wafer cassettes 68 to 6d (Fig. Set to standby state.

Next, the wafer boat 3a for the reactor main body 2a is moved to a predetermined transfer position by the transfer mechanism 9 (FIG.-A1).
Then, the transfer mechanism 8, which has moved to the position relative to the wafer cassette 6b, transfers the dummy wafers one by one from the wafer cassette 6b to the wafer boat 3a held by the transport mechanism 9 (A2 in the same figure). Next, the transfer mechanism 8 is moved to a position relative to the wafer cassette 6a, and the transfer mechanism 8 is moved to a position relative to the wafer cassette 6a.
From there, semiconductor wafers 4 for processing are transferred one by one to the wafer boat 3a (A3 in the same figure). Note that several dummy wafers, for example, three dummy wafers, are placed at the top and bottom of the wafer board 3a, and a plurality of processing wafers, for example two, are placed between these dummy wafers.
Place 5 pieces.

When the transfer by the transfer mechanism 8 is completed, the wafer boat 3a is then transferred by the transfer mechanism 9 to the boat elevator 5.
(A4 in the same figure).

Then, the boat elevator 5a raises the temperature to, for example, 800°C.
A wafer boat 3a is placed inside the reactor main body 2a which has been preheated to a certain degree.
Load. Thereafter, the inside of the reactor main body 2a is heated to a predetermined temperature, for example, about 1200°C, and a predetermined gas, for example, 5IH is heated.
2C12, t (C1+12 is distributed to the semiconductor wafer 4
For example, silicon epitaxial growth is performed. For example, in the case of silicon epitaxial growth, this process
It takes, for example, 30 minutes to raise the temperature, 80 minutes to process, and 30 minutes to lower the temperature.

On the other hand, the transport mechanism 9, which has completed transporting the wafer boat 3a on the reactor main body 2a side, moves to the reactor main body 2b side and moves the wafer boat 3b to a predetermined transfer position (Fig.
Bl). While processing is being carried out on the reactor main body 2a side, dummy wafers and semiconductor wafers 4 for processing are transferred from the wafer cassettes 6C and 6d to the wafer boat 3b of the reactor main body 2b through the transfer groove 8. After the transfer is completed, the wafer boat 3b is transferred onto the boat elevator 5b by the transport mechanism 9 (Fig. 84), and the wafer boat 3b is placed in a standby state until the processing in the reactor main body 2a is completed. do.

When the processing in the reactor main body 2a side is completed, the wafer boat 3b is loaded into the reactor main body 2b by the boat elevator 5b (Fig. 85), and the processing is performed (Fig. 86).
.

On the other hand, the boat elevator 5a is descending (Fig. A7),
The unloaded wafer boat 3a is moved to a predetermined transfer position by the transfer mechanism 9 (A8 in the same figure), and the processed semiconductor wafers 4 are transferred one by one to the wafer cassette 6a by the transfer mechanism 8. . The wafer cassette 6a that has been transferred is placed in a vertical position (A10 in the figure), and the wafer cassette 6a is replaced.

After aligning the orientation flat of the new wafer cassette 6a, the above-described wafer transfer process (A1-A4 in the same figure) is performed, and the process is repeated. In addition, when processing is performed continuously, the dummy wafers remain placed on the wafer board 3a, and only the wafers for processing are transferred.

Furthermore, when the treatment is completed on the reactor main body 2b side,
The wafer boat 5b descends (Bl in the same figure), the processed wafers are transferred one by one (89 in the same figure), and then replaced with a new wafer cassette 6d (BIO in the same figure).
~B11), the process is repeated.

In this way, the heat treatment process of semiconductor wafers and the transfer process of unprocessed and processed semiconductor wafers between the processing substrate holder and the transport substrate holder are alternately carried out for the two reactor bodies. By repeating this process, one transfer mechanism can be shared by two reactor bodies.

By performing the above transfer process using the processing time in one reactor main body, even if the substrate to be processed is transferred in a single wafer type, the single wafer type transfer mechanism Compared to a heat treatment apparatus equipped with a heat treatment apparatus, it is possible to reduce the apparatus cost and the installation area of the apparatus without reducing the processing efficiency at all.

[Effects of the Invention] As explained above, according to the substrate heat treatment method of the present invention, when transferring a substrate to be processed in a single wafer type, processing efficiency can hardly be reduced, and a vertical heat treatment apparatus can be used. It becomes possible to operate the substrate transfer mechanism, which is an accompanying mechanism, more efficiently, thereby making it possible to reduce the device cost and the installation area.

[Brief explanation of the drawing]

Fig. 1 is a top view showing the configuration of a vertical heat treatment apparatus used in an embodiment of the present invention, Fig. 2 is a front view of Fig. 1, and Fig. 3 shows the processing steps of an embodiment of the present invention. It is a diagram. 18 ~ IC... Housing, 2a, 2b...
Reactor main body, 3a, 3b...Wafer boat, 4
... Semiconductor wafer, 5a, 5b ... Boat elevator, 6a to 6d ... Wafer cassette, 7 ... Wafer cassette storage section, 8 ...
... Transfer mechanism, 9... Conveyance mechanism.

Claims (1)

[Claims] (1) When performing the desired heat treatment on the substrate to be processed in each of the plurality of reactor bodies installed approximately vertically, the plurality of reactor bodies are A substrate transfer mechanism provided between the main bodies transfers the substrates to be processed one by one from the transport substrate holder to the processing substrate holder in the second reactor main body, and transfers them to the plurality of reactor main bodies. A method for heat processing a substrate, characterized in that the heat treatment and the transfer of the substrate to be processed are sequentially performed and the processing is repeated continuously.