JPH01238011A - Heat-treatment unit for semiconductor wafer - Google Patents

Abstract

PURPOSE:To reduce crystal defects by doubling the number of wafers to be heat-treated per unit time, heating only one side of each wafer, and having temperature rise of the wafers by inserting a pair of wafers in contact with each other into a hot oven and heat-treating the same. CONSTITUTION:Wafers 7, 8 are placed back to back on a supporting jig 9 taken out below a hot oven 1. The supporting jig 9, on which the wafers 7, 8 are placed, and a conveyor bench 12 are moved upward. Hereby, the wafers 7, 8 are accommodated in the hot oven 1. After the wafers 7, 8 are heated for a given period of time in the hot oven 1, they are taken out downward the hot oven 1 by a driving mechanism 13, and cooled and replaced for new wafers. Hereby, heat transmission through each wafer is restricted only to one side thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat treatment apparatus for semiconductor wafers such as a diffusion apparatus and a CVD apparatus, and more particularly to an apparatus structure suitable for uniformly heat-treating semiconductor wafers.

[Conventional technology]

As described in Japanese Patent Application Laid-Open No. 60-171723, the conventional apparatus opens the bottom of a vertical cylindrical high-temperature furnace, inserts horizontally supported wafers one by one into the high-temperature furnace, and heats the wafers. It was structured to do so.

On the other hand, a method (batch heat treatment method) in which a large number of wafers are inserted in parallel at a narrow pitch into a cylindrical high-temperature furnace to heat the wafers has also been widely used.

[Problem to be solved by the invention]

The above-mentioned conventional technology heat-treats each wafer one by one, so the number of wafers heat-treated per hour is small, and the wafers are inserted one by one into a high-temperature furnace, so both sides of the wafer are heated, and the temperature of the wafer increases rapidly. There was a problem that the crystal defects were large and crystal defects occurred.

In addition, in the conventional technology described below, when a row of wafers with a narrow pitch is inserted into a high-temperature furnace at high speed, a large temperature distribution occurs within the wafer surface where the periphery is higher than the center, so it is difficult to uniformly perform heat treatment for a short time. I couldn't do it.

An object of the present invention is to provide a heat treatment apparatus structure that can uniformly heat all wafers in a short time in a high-temperature furnace, can heat a large number of wafers, and does not generate crystal defects in the wafers.

[Means to solve the problem]

The above object is achieved by inserting two wafers in close contact with each other into a box-shaped or cylindrical high-temperature furnace and performing heat treatment.

[Effect]

By heat-treating two wafers in close contact with each other, the number of wafers heat-treated per unit time is doubled compared to the case of heat-treating one wafer at a time. In addition, since the two wafers are in close contact with each other, each wafer is heated only from one side, so the temperature increase rate of the wafers is halved compared to the case of one wafer at a time, and crystal defects do not occur. Since the heater heats the wafer uniformly everywhere within the wafer surface, the temperature within the wafer surface is uniform even during transient periods.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a longitudinal sectional view of a high temperature furnace of a diffusion device to which the present invention is applied. FIG. 2 is an enlarged external view of the wafer support jig and wafer shown in FIG. 1.

The high-temperature furnace 1 has a rectangular parallelepiped shape, and is divided into two flat plate-shaped bees 921 on the left and right sides, a reaction tube 3 (made of quartz glass, etc.), a soaking tube 4 (made of silicon carbide, etc.), and a heat insulating material 5.
A high temperature furnace 1 is constructed and placed on a pedestal 6. The two wafers 7 , 8 are placed on a support jig 9 (made of quartz glass, etc.) with their back surfaces tightly attached to each other, and inserted into the high temperature furnace 1 . The upper end of the support jig 9 has a groove 10 in which the wafers 7, 8 are supported together in the same groove. The support jig 9 has a flange 11 at its lower end and is attached to a conveyor table 12. The transport table 12 is a drive mechanism 13
The support jig 9. Wafer 7.8 arrow 1
It moves up and down in direction 4.

Inside the reaction tube 3, nitrogen or
Gases such as argon, oxygen, and water vapor are flowing.

The heater 2 is divided into a plurality of zones, and the amount of heat generated in each zone is controlled by a controller, so that a uniform temperature field is formed in the internal space of the high temperature furnace 1.

The operation of heat-treating a wafer using the diffusion device configured as described above will be described below. Two wafers 7° 8 are placed on the support jig 9 taken out from the lower part of the high temperature furnace 1 with their backs in close contact with each other.

By the action of the drive mechanism 13, the support jig 9 and the conveyance table 12 carrying the wafer 7.8 move upward, and the wafer 7.8 is housed inside the high temperature furnace 1. After the wafers 7.8 are heated inside the high temperature furnace 1 for a predetermined time, they are taken out from the bottom of the high temperature furnace 1 by the action of the drive mechanism 13, cooled, and replaced with two new wafers, and the above operation is repeated.

Because the two wafers are closely contacted during insertion, heating in the high-temperature furnace, removal, and cooling, heat transfer to each wafer is limited to only one side.

According to this embodiment, since the flat heater 2 is provided substantially parallel to the surface of the wafer 7.8, the wafer can be heated to a uniform temperature.

Furthermore, since the high-temperature furnace 1 is box-shaped, the high-temperature furnace 1 can be made compact.

In the above explanation, a rectangular parallelepiped-shaped high-temperature furnace was used, but a cylindrical-shaped high-temperature furnace would have the same effect.

〔Effect of the invention〕

According to the present invention, it is possible to maintain a uniform temperature within the wafer surface, including during transient times, and uniform short-time heat treatment becomes possible.

Furthermore, since two wafers are heat-treated at the same time, the number of wafers heat-treated per hour (throughput) can be increased compared to heat-treating one wafer at a time.

Furthermore, compared to heat treatment for each wafer, the temperature rise rate of the wafer is lower, and crystal defects do not occur in the wafer. In addition, since the two wafers are in close contact with each other, there is no chance of outside air being sandwiched between the wafers and brought into the high-temperature furnace.
Since the inside of the high-temperature furnace can be kept clean, the yield of heat treatment is improved.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view of a diffusion device according to an embodiment of the present invention;
The figure is an enlarged external view of the wafer support jig and wafer shown in FIG. 1. 1... High temperature furnace, 2... Heater, 3... Reaction tube, 4
... Soaking tube, 5... Insulating material, 6... Frame, 7...
・Wafer, 8... Wafer, 9... Support jig, 10.
...Groove, 11...Flange. 12... Conveyance table, 13... Drive mechanism. Ton 2 ro1, g---Kueha lρ-ichiichizo

Claims (1)

[Claims] 1. In an apparatus in which a heating space is formed in the furnace using a heater installed inside a high-temperature furnace, and a semiconductor wafer is housed in the heating space and heat-treated, two semiconductor wafers are brought into close contact with each other and heat-treated at the same time. Features of semiconductor wafer heat treatment equipment.