JPH02102523A - Wafer boat - Google Patents

Abstract

PURPOSE:To perform the excellent heat treatment for augmenting the yield of devices by a method wherein, within the applicable wafer boat, the wafer ends come into no contact with a wafer boat while wafer holders are brought into linear contact with the wafer rear sides to reduce the contact space between the wafer rear sides and the wafer holders. CONSTITUTION:Within the title wafer boat, the wafer 8 ends come into no contact with a holding bar of the boat 11; wafer holders with round surfaced protrusions 10 or rings connecting the rods of wafer boat 11 are provided; the wafer rear sides 13 are brought into linear contact with the wafer holders. That is, the wafer ends come into no surface contact but linear contact with the holders. Consequently, the tensile stress and thermal stress are relieved to restrain any defect such as slip etc., from occurring. Through these procedures, excellent heat treatment can be performed to augment the yield of devices.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a port provided in a vertical heat treatment apparatus, and particularly relates to a vertical wafer boat provided in a vertical vapor phase growth apparatus.

[Conventional technology]

Conventionally, the vertical wafer boat included in a vertical vapor phase growth apparatus has a large area of the holding part in contact with the wafer.
Due to the difference in thermal conductivity between the wafer and the port support, thermal strain was applied to the wafer, causing crystal defects. To avoid this, hold the wafer at 3 or 4 points,
The part that holds the wafer protrudes like a rod from the port support rod, and a port is used in which the end of the wafer and the back surface around the wafer are in surface contact with the boat support rod and the holding part (for example, 61-191015
Publication No.). Alternatively, a port is used in which a rectangular groove slightly thicker than the thickness of the wafer is formed in the port support rod, and one end of the wafer and the periphery of the back surface of the wafer are in surface contact with the groove.

[Problem to be solved by the invention]

As mentioned above, when a wafer is taken in or taken out of the port provided in a conventional vertical gas phase reactor, the contact area between the support part of the port and the wafer periphery is large, resulting in minute scratches on the wafer periphery. The disadvantage is that slips can occur under these areas. In addition, tensile stress is acting at one end of the wafer, so contact with the wafer holding part of the port at one end of the wafer adds to the tensile stress, and also increases the heat capacity between the back end of the wafer and the wafer holding part of the port. There is a disadvantage that thermal stress resulting from the difference is added, and defects such as slips are likely to occur.

[Means to solve the problem]

The port of the present invention is a vertical wafer port in which the main surface of the wafer is substantially horizontal and holds a plurality of wafers at substantially constant intervals. A protrusion with a rounded surface or a ring connecting the rods of the wafer port is attached to the wafer, and the back surface of the wafer is held in line contact with the wafer holder.

In the present invention, in the part that holds the wafer, one end of the wafer and the part that holds the wafer do not contact each other, and the back surface of the wafer and the holding part do not come into surface contact but are in line contact. Compared to conventional methods, the present invention eliminates contact between one end of the wafer and the wafer holder, and there is a line contact between the back surface of the wafer and the wafer holder, which alleviates tensile stress and thermal stress, thereby reducing defects such as slipping. suppress.

In addition, the present invention holds the back surface of the wafer in line contact with the back surface of the wafer compared to the conventional method, so that minute scratches are less likely to occur.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention.

A reaction tube installed in a vertical resistance heating furnace 1 is composed of an outer tube 2 and an inner tube 3, and is supported by a pedestal 4. The inner tube 3 is provided with a nozzle 5 for supplying a reaction gas. The wafers 7 are held in the rotatable port 6 at arbitrary intervals.

FIGS. 2(a) and 2(b) are an enlarged vertical sectional view and a plan view of the area A surrounded by the broken line in FIG. 1, respectively, and illustrate the structure of the support portion of the port in more detail. . The port 11 that holds the wafer 8 is configured with a lock-shaped support part 9, and the end 12 of the wafer does not come into contact with the port 11, and the back surface 13 of the wafer is located approximately 1 cm away from the end 12 of the wafer.
are held in line contact by a protrusion 10 of a lock-shaped support 9.

Using this port, 50 wafers with a diameter of 6 inches were filled and heat treated at 1100°C. When a conventional port was used, many slips of 1 to 2 cm were observed in the portion of the wafer held in the port, but when the port of the present invention was used, there was no slippage in the portion of the wafer held in the port. No occurrence of this was observed, confirming the superiority of the present invention.

FIGS. 3(a) and 3(b) are a cross-sectional view and a plan view, respectively, of another embodiment of the present invention, and similarly to FIG. 2, the wafer holder is configured. A ring 16 that connects the wafer port support rods 15 is configured as a wafer holding portion on the boat support rod 15 that holds the wafer 14.
One end 17 of the wafer does not touch the port 18, and the back surface 19 of the wafer, which is approximately 1 cm away from the one end 17 of the wafer, is connected to the ring 1.
6 and hold it in line contact at the top.

Using this boat, fill 50 pieces of 6″φ wafers and
Heat treatment was performed at 100°C. When using a conventional port, 1 to 2
A large number of slips of cm cm were observed, but when the port of the present invention was used, no slip was observed in the portion of the wafer held by the port, confirming the superiority of the present invention.

〔Effect of the invention〕

As explained above, the present invention provides a port having a wafer holding part that makes line contact with the backside of the wafer in order to prevent the end of the wafer from coming into contact with the port and to reduce the contact area between the backside of the wafer and the part that holds the wafer. By using a wafer, high-quality heat treatment is applied to suppress the occurrence of slippage caused by minute scratches on the wafer surface when the wafer is inserted or removed from the port, reducing the effect of defects on the electrical characteristics of the device. Therefore, the yield of devices is significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a vertical vapor phase growth apparatus according to an embodiment of the present invention, and FIGS. 2(a) and 2(b) are enlarged longitudinal sectional views of a portion A surrounded by a broken line in FIG. 1. and a plan view, and FIG. 3 is a longitudinal sectional view and a plan view of another embodiment of the present invention. 1...Resistance heating furnace, 2...Outer tube, 3...
...Inner tube, 4... Frame, 5... Nozzle, 6... Port, 7... Wafer 8.
... Wafer 9 ... Lock-shaped support part, 10
...Protrusion, 11...Port, 12.
... One end of wafer, 13 ... Back side of wafer, 14 ... Wafer 15 ... Port support rod, 16 ... Ring, 17 ...・・・・・・
One end of the wafer, 18... port, 19...
...Back side of wafer. Agent Patent Attorney Susumu Uchihara 1st

Claims (1)

[Claims] In a vertical wafer boat that holds a plurality of wafers at substantially constant intervals with the main surface of the wafers being substantially horizontal, the wafers are held on a plurality of support rods erected substantially perpendicular to the main surface of the wafers. A wafer port, wherein the wafer port holds the wafer by making partial and circular line contact at a portion of the back surface of the wafer that is located inside the end of the wafer at a predetermined distance.