JPH10247680A - Fork for transferring wafer to high-temperature oven and thermal treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an in-plane temperature difference and a thermal shock which occur in a wafer to an irreducible minimum when it is loaded into or unloaded from a high-temperature over by a method wherein a transfer fork is formed of transparent material which transmits infrared rays, and supports which are formed of black body and support wafer to be processed are provided to the transfer fork. SOLUTION: A fork 15 is formed of transparent body which transmits infrared rays and is high in heat-resistant properties, it is preferable that the fork 15 is formed of material such as transparent quartz which scarcely serves as a pollution source which contaminates a wafer W, and protrudent supports 17 which support the underside of a wafer W at two or more points are provided to the recessed part 16 of the fork 15. The protrudent supports 17 are formed of black body which absorbs infrared rays and is high in heat resistance, and it is preferable that the protrudent supports 17 are formed of material such as silicon carbide which scarcely serves as a pollution source which contaminates a wafer W. The silicon carbide support 17 is formed like a mushroom or a pin. The fork 15 is transparent, so that infrared rays radiated from a heater penetrate through the fork 15, and no shadow of the fork 15 is case on the wafer W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer fork to a high-temperature furnace and a heat treatment apparatus.

[0002]

2. Description of the Related Art In a semiconductor device manufacturing process, oxidation, diffusion, CV
Various types of heat treatment apparatuses are used for performing processes such as D (Chemical Vapor Deposition) and annealing.
As one type of heat treatment apparatus of this type, a transfer mechanism having a fork (also referred to as a pick) for supporting the wafer loads the wafer into a processing chamber heated to a high temperature in advance from a horizontal direction and heat-treats the wafer. Single-wafer heat treatment apparatuses have been proposed.

According to the above-described heat treatment apparatus, since the inside of the treatment chamber is preliminarily heated to a high temperature, it is possible to quickly raise the temperature of the wafer and carry out the heat treatment, thereby improving the throughput. The fork is made of a material having heat resistance and less likely to become a contamination source of the wafer, for example, ceramics or the like.

[0004]

However, in the above-described heat treatment apparatus, the fork is made of an opaque material, so that the wafer is placed on the fork and carried into the processing chamber heated to a high temperature in advance, and after the heat treatment. When a wafer is loaded from a processing chamber onto a fork and unloaded, the fork blocks infrared rays from a heating source and creates a shadow of the fork on the wafer surface. The shadow of the fork causes a temperature distribution on the wafer, that is, an in-plane temperature difference. Had occurred. Further, when the wafer is carried out of the processing chamber after the heat treatment, the cold fork and the hot wafer after the heat treatment come into contact with each other, thereby giving a thermal effect or a thermal shock to the wafer. As described above, due to the in-plane temperature difference or thermal shock generated on the wafer, slip (crystal shift) is likely to occur on the wafer, which causes a problem of lowering the quality and lowering the yield of semiconductor devices.

Accordingly, the present invention has been made to solve the above problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a high-temperature furnace capable of reducing as much as possible the in-plane temperature difference and thermal shock of a substrate to be processed which occur when the substrate is carried into and out of the high-temperature furnace while supporting the substrate. To provide a fork for transport to a vehicle. Another object of the present invention is to provide a transfer mechanism having a fork for supporting a semiconductor wafer, wherein the semiconductor wafer has an in-plane temperature difference generated when the semiconductor wafer is loaded or unloaded from a horizontal direction into a processing chamber heated to a high temperature in advance. Another object of the present invention is to provide a heat treatment apparatus capable of reducing thermal shock as much as possible, reducing the possibility of occurrence of slip of a semiconductor wafer, and improving the quality and the yield of semiconductor devices.

[0006]

In order to achieve the above object, the invention according to claim 1 of the present invention relates to a carrier for supporting a substrate to be processed and carrying it into and out of a high-temperature furnace. The fork is characterized in that the fork is formed of a transparent body through which infrared light is transmitted, and the fork is provided with a plurality of support portions made of a black body for supporting the substrate to be processed.

The invention according to claim 2 is characterized in that the transparent body in the invention according to claim 1 is transparent quartz.

The invention according to claim 3 is characterized in that the black body in the invention according to claim 1 is silicon carbide.

According to a fourth aspect of the present invention, there is provided a heat treatment apparatus for carrying a semiconductor wafer into a processing chamber heated to a high temperature in advance from a horizontal direction by a transfer mechanism having a fork for supporting the semiconductor wafer and performing a heat treatment. Are formed of transparent quartz through which infrared light is transmitted, and a support having a small heat capacity made of silicon carbide for supporting the semiconductor wafer at a plurality of points is provided on the fork.

According to the first aspect of the present invention, a transfer fork for supporting a substrate to be processed and carrying it into and out of the high-temperature furnace is formed of a transparent body through which infrared rays can pass, and the fork is formed of a transparent body. Since a plurality of support portions made of a black body for supporting the substrate to be processed are provided, it is possible to dilute or eliminate the shadow of a fork generated on the substrate to be processed when loading and unloading the substrate into a high-temperature furnace, It is possible to quickly raise the temperature of the supporting portion that comes into contact with the substrate to be processed at the time of unloading to the same temperature as the substrate to be processed. Therefore, it is possible to reduce or eliminate as much as possible the in-plane temperature difference and thermal shock of the substrate to be processed which occur when the substrate to be processed is carried into and out of the high-temperature furnace while being supported. Become.

According to the second aspect of the present invention, since the transparent body is made of transparent quartz, a transparent fork can be easily obtained.

According to the third aspect of the present invention, since the black body is made of silicon carbide, a support having good heat absorption can be easily obtained.

According to the fourth aspect of the present invention, the fork of the transfer mechanism in the heat treatment apparatus for carrying the semiconductor wafer into the processing chamber heated to a high temperature in advance from a horizontal direction and performing the heat treatment is formed of transparent quartz through which infrared rays are transmitted. At the same time, since a small heat capacity supporting portion made of silicon carbide for supporting the semiconductor wafer at a plurality of points is provided on the fork,
It is possible to dilute or eliminate the shadow of a fork generated on a semiconductor wafer when carrying in / out a processing chamber, and to quickly raise the temperature of a support portion that comes into contact with the semiconductor wafer at the time of carrying out to the same temperature as the semiconductor wafer. Becomes possible.
For this reason, a transfer mechanism having a fork for supporting the semiconductor wafer can reduce an in-plane temperature difference of the semiconductor wafer and a thermal shock generated when the semiconductor wafer is loaded or unloaded from a horizontal direction into a processing chamber heated to a high temperature in advance. This can be reduced or eliminated as much as possible, and the quality and the yield of semiconductor devices can be improved.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1A and 1B are views showing a transport fork according to an embodiment of the present invention, in which FIG. 1A is a plan view, FIG. 1B is a cross-sectional view, and FIG. 2 is a cross-sectional view showing an example of a heat treatment apparatus to which the present invention is applied. 3A and 3B are views showing the form of the support portion, wherein FIG. 3A is a sectional view of an embedded type, and FIG.

First, an example of the heat treatment apparatus will be described with reference to FIG. This heat treatment apparatus is configured as a single-wafer heat treatment apparatus having a high-temperature furnace 1 which is a heat treatment furnace for heat-treating a disc-shaped semiconductor wafer W as a substrate to be processed one by one. The heat treatment apparatus is configured to be suitable for, for example, a CVD process.

The high-temperature furnace 1 has a processing chamber (process chamber) 2 for horizontally storing a wafer W, and a heater 3 as a heating source capable of heating the inside of the processing chamber 2 to a high temperature, for example, 800 to 1000 ° C. ing. The processing chamber 2 is preferably formed in a circular container shape from a heat-resistant material, for example, quartz. It is preferable that the heater 3 is formed of, for example, a heating resistor, and is formed in a planar shape in order to uniformly heat the wafer W in a plane, and is disposed above and below the processing chamber 2.

The outside of the processing chamber 2 and the heater 3 is
It is covered with a heat insulating material 4. The outside of the heat insulating material 4 is preferably covered with, for example, an outer shell (not shown) having a water-cooled jacket structure. The processing chamber 2 is provided with a gas supply pipe 5 for supplying a processing gas, an inert gas such as nitrogen gas, a cleaning gas, etc. into the processing chamber 2, and a predetermined reduced pressure atmosphere inside the processing chamber 2. Or vacuum,
For example, a vacuum pump for evacuating to 10 ⁻² to 10 ⁻³ Torr and an exhaust pipe 6 having a pressure control mechanism are connected.

The wafer W loaded into the processing chamber 2 is
In the illustrated example, a plurality of, for example, three quartz support pins 7 for horizontally supporting the lower surface of the wafer W are provided upright as holding means for holding. Note that the holding means may be a planar member that holds a surface (lower surface or upper surface) of the wafer W opposite to the surface to be processed, or a ring member that holds a peripheral portion of the wafer W. Good.

An entrance 8 for loading / unloading the wafer W is provided at a side portion of the processing chamber 2, and a transfer chamber 10 having a transfer mechanism 9 for transferring the wafer W is provided at the entrance 8 as an open / close valve. It is connected via a gate valve 11. The transfer chamber 10 has a pressure substantially equal to that of the processing chamber 2, preferably a pressure slightly higher than that of the processing chamber 2 so that processing gas does not leak. For example, when the processing chamber is 10 ⁻³ Torr,
^-2 Torr. In the transfer chamber 10,
Load lock chamber 12 for reducing pressure and replacing normal pressure (atmospheric pressure)
Are connected via a gate valve 13, and a transfer chamber for transferring wafers W to and from a wafer cassette under normal pressure is connected to the load lock chamber 12 via a gate valve (not shown). .

The transport mechanism 9 can move up and down, and
The transfer arm 14 includes a transfer arm 14 having a multi-joint arm structure that can be rotated and extended horizontally, and a transfer fork 15 that supports the wafer W is provided at a distal end of the transfer arm 14. As shown in FIGS. 1A and 1B, the fork 15 is formed in a vertically long thin plate narrower than the width of the wafer W, and the fork 15 drops on the upper surface on the tip side during the transfer. It is preferable that a concave portion 16 for accommodating the wafer W be formed so as not to be disturbed. Further, the tip of the fork 15 is used to avoid interference with the support pins 7 in the processing chamber 2.
It is preferably branched in a U shape or the like.

The fork 15 is formed of a transparent body through which infrared light passes. The transparent body is preferably a material that has heat resistance and does not become a contamination source of the wafer W, for example, transparent quartz. On the fork 15, a plurality of, for example, 3 to 4, in the illustrated example, four projecting support portions (support pin portions) 17 for directly supporting the lower surface of the wafer W at a plurality of points in the concave portions 16 are provided. Is provided. These protruding support portions 17 are formed of a black body that absorbs infrared rays. The black body is preferably a material having heat resistance and not a source of contamination of the wafer W, for example, silicon carbide (SiC). The support part 1
7 is preferably formed with a small volume in order to reduce the heat capacity.

As shown in FIG. 3 (a), for example, the support 17 is made of a silicon carbide support 17 formed in a mushroom shape or a pin shape or the like. As shown in FIG. 3B, a fitting type in which the fitting portion is fitted into the concave portion 18 or a coating type in which the surface of the projection 19 formed on the fork 15 is covered with a silicon carbide film or a cover 20, as shown in FIG. Things are adopted.
The shape of the portion of the support portion 17 that comes into contact with the wafer W is preferably spherical as shown in the illustrated example, but may be flat.

Next, the operation of the transfer arm and the heat treatment apparatus having the above-described configuration will be described. First, the inside of the processing chamber 2 of the high temperature furnace 1 is controlled to a predetermined reduced pressure state, and is controlled to a predetermined heat treatment temperature by the heater 3. In this state, when the gate valve 11 on the load lock chamber 12 side is opened, the transfer arm 1 of the transfer mechanism 9 in the transfer chamber 10 is opened.
4 is to advance the fork 15 horizontally toward the load lock chamber 12 and to move the fork 15 from the wafer cassette to the load lock chamber 1 in advance.
After receiving the unprocessed wafer W transferred to 2 on the support portion 17 of the fork 15, the wafer W retreats and returns to the transfer chamber 10. When the transfer arm 14 returns to the transfer chamber 10, the gate valve 13 on the load lock chamber 12 side closes.

Next, when the direction of the fork 15 is changed and the gate valve 13 on the high-temperature furnace side is opened, the transfer arm 14 advances the fork 15 horizontally toward the processing chamber 2 to move the wafer W into the processing chamber 2. After the fork 15 is slightly lowered to transfer the wafer W onto the support pins 7, the fork 15 retreats and returns to the transfer chamber 10. When the transfer arm 14 returns to the transfer chamber 10, the gate valve 11 on the high-temperature furnace side closes and the processing chamber 2
A predetermined heat treatment for the wafer W is started therein. When the heat treatment is completed, the wafer W after the heat treatment is unloaded from the processing chamber W and transferred to the load lock chamber 12 by the operation reverse to the above, and returned from the load lock chamber 12 to the wafer cassette via the transfer chamber. . In this manner, the heat treatment of the wafer W is performed sequentially and continuously.

By the way, in the conventional heat treatment apparatus,
Since the fork 15 is made of an opaque material, the wafer W is placed on the fork 15 when the wafer W is loaded on the fork 15 and loaded into the processing chamber 2 which has been heated to a high temperature in advance, and after the heat treatment. When the wafer W is carried out, infrared rays radiated from the heater 3 are blocked by the fork 15 and a shadow of the fork 15 is generated on the wafer surface, and the shadow of the fork 15 causes an in-plane temperature difference on the wafer W.

On the other hand, according to the heat treatment apparatus of the present embodiment, since the fork 15 is made of a transparent material, infrared rays from the heater 3 pass through the fork 15, and the heat is applied to the wafer surface. The shadow of the fork 15 does not occur, or even if it occurs, it becomes a very faint shadow. in this way,
Since the shadow of the fork 15 reflected on the wafer surface can be eliminated or diluted, the wafer W generated by the shadow of the fork 15 when loading or unloading the wafer W from the horizontal direction into the processing chamber 2 heated to a high temperature in advance. Can be reduced or eliminated as much as possible.

In this case, since the fork 15 is formed of transparent quartz, which is a transparent body, it has heat resistance,
Moreover, a transparent fork 1 that does not become a contamination source of the wafer W
5 is easily obtained. Further, a plurality of projecting support portions 17 for supporting the wafer W at a plurality of points are provided on the fork 15, and since these support portions 17 are formed of a black body,
After the heat treatment, while the fork 15 enters the processing chamber 2 from the transfer chamber 10 at the standby position to retrieve the wafer W in order to carry out the wafer W from the processing chamber 2, the support unit 17 emits infrared rays from the heater 3. It absorbs efficiently and heats up quickly.

As described above, the support portion 1 that comes into contact with the wafer W
7 can be quickly raised to the same temperature as the wafer W before coming into contact with the wafer W, so that the hot wafer W after the heat treatment is removed from the processing chamber 2 by the cold fork 15.
Accordingly, thermal shock of the wafer W generated when the wafer W is unloaded can be reduced or prevented. In this case, by forming the support 17 from silicon carbide, which is a black body, the support 17 having good heat absorption can be easily obtained.

The support portion 17 is formed sufficiently smaller than the fork 15 and has a small heat capacity, so that the temperature can be raised more quickly, the rising speed is fast, and the transfer speed of the transfer arm 14 is sufficient. Can be handled. Therefore, not only when the wafer W is carried out, but also when the wafer W is carried in, the temperature of the support portion 17 can be raised together with the wafer W without causing a temperature difference, and the wafer W is not affected by heat. As described above, the in-plane temperature difference of the wafer W, thermal shock, and thermal influence that occur when the wafer W is loaded or unloaded from the horizontal direction into the processing chamber 2 heated to a high temperature in advance is suppressed or prevented. Slip can be prevented, and the quality and the yield of semiconductor devices can be improved.

FIG. 4 is a plan view of a transport fork showing another embodiment of the present invention. 4, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description is omitted. In the transfer fork 15 of the present embodiment, a portion (base side) 15a that is not directly exposed to infrared radiation in the processing chamber is formed of opaque quartz having a lower thermal conductivity than transparent quartz.

Opaque quartz is obtained, for example, by including air bubbles in quartz, so that the thermal conductivity is further lower than that of transparent quartz (having a lower thermal conductivity than alumina or silicon carbide). According to this fork 15, in addition to obtaining the same effect as the fork of FIG. 1, the base side 15a, which is not directly exposed to infrared radiation, is formed of opaque quartz and has a low thermal conductivity. The influence of heat on the arm 14 due to heat conduction can be suppressed, and the durability of the transport mechanism 9 can be improved.

Although the preferred embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-discussed preferred embodiments, and various design changes and the like are possible without departing from the gist of the present invention. Is possible. For example, the heat treatment apparatus to which the present invention is applied may be one that performs, for example, oxidation, diffusion, annealing, or the like, in addition to CVD. Further, as the substrate to be processed, for example, an LCD substrate or the like can be applied in addition to the semiconductor wafer.

[0033]

In summary, according to the present invention, the following effects can be obtained.

(1) According to the first aspect of the present invention, the transfer fork for supporting the substrate to be processed and carrying it into and out of the high-temperature furnace is formed of a transparent body through which infrared rays can pass. Since the fork is provided with a plurality of support portions made of a black body for supporting the substrate to be processed, the shadow of the fork generated on the substrate to be processed at the time of carrying in and out of the high-temperature furnace can be diluted or eliminated. In addition, the temperature of the support portion that comes into contact with the substrate to be processed at the time of unloading can be quickly raised to the same temperature as the substrate to be processed. For this reason, it is possible to reduce or eliminate as much as possible the in-plane temperature difference and the thermal shock of the substrate to be processed, which occur when the substrate is carried into and out of the high-temperature furnace while supporting the substrate.

(2) According to the second aspect of the invention, since the transparent body is made of transparent quartz, a transparent fork can be easily obtained.

(3) According to the third aspect of the invention, since the black body is made of silicon carbide, a supporting portion having good heat absorption can be easily obtained.

(4) According to the fourth aspect of the present invention, the transparent quartz through which the infrared rays pass through the fork of the transfer mechanism in the heat treatment apparatus for carrying the semiconductor wafer into the processing chamber heated to a high temperature in advance from the horizontal direction and performing the heat treatment. And a small heat capacity support portion made of silicon carbide for supporting the semiconductor wafer at a plurality of points is provided on the fork, so that the shadow of the fork generated on the semiconductor wafer when the semiconductor wafer is carried in and out of the processing chamber is diluted. In addition to this, it is possible to quickly raise the temperature of the support portion that comes into contact with the semiconductor wafer at the time of unloading to the same temperature as the semiconductor wafer. For this reason, a transfer mechanism having a fork for supporting the semiconductor wafer can reduce an in-plane temperature difference of the semiconductor wafer and a thermal shock generated when the semiconductor wafer is loaded or unloaded from a horizontal direction into a processing chamber heated to a high temperature in advance. It can be reduced or eliminated as much as possible, and the quality and the yield of semiconductor devices can be improved.

[Brief description of the drawings]

FIGS. 1A and 1B are diagrams showing a transport fork according to an embodiment of the present invention, wherein FIG. 1A is a plan view and FIG.

FIG. 2 is a sectional view showing an example of a heat treatment apparatus to which the present invention is applied.

3A and 3B are diagrams showing a form of a supporting portion, wherein FIG. 3A is a cross-sectional view of an embedded type, and FIG.

FIG. 4 is a plan view of a transport fork showing another embodiment of the present invention.

[Explanation of symbols]

 W Semiconductor wafer (substrate to be processed) 1 High temperature furnace 2 Processing chamber 9 Transfer mechanism 15 Fork 17 Support

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Wataru Okase 1-2-141 Machiya, Shiroyama-cho, Tsukui-gun, Kanagawa Prefecture Inside the Tokyo Electron Tohoku Co., Ltd. Sagami Business Office

Claims (4)

[Claims] 1. A transfer fork for supporting a substrate to be processed and carrying it into and out of a high-temperature furnace,
A fork for transporting to a high-temperature furnace, wherein the fork is formed of a transparent body through which infrared light is transmitted, and the fork is provided with a plurality of support portions made of a black body for supporting the substrate to be processed. 2. The fork for transferring to a high-temperature furnace according to claim 1, wherein the transparent body is transparent quartz. 3. The fork for transferring to a high-temperature furnace according to claim 1, wherein the black body is silicon carbide. 4. A heat treatment apparatus for carrying a semiconductor wafer into a processing chamber heated to a high temperature in advance from a horizontal direction by a transfer mechanism having a fork for supporting the semiconductor wafer and heat-treating the semiconductor wafer. A heat treatment apparatus, comprising: a support portion made of quartz and having a small heat capacity made of silicon carbide for supporting the semiconductor wafer at a plurality of points on the fork.