JPH03229414A - Thermal treatment apparatus - Google Patents

Abstract

PURPOSE:To reduce variation between wafers subjected to a batch treatment and improve a utilization factor by a method wherein a first exhaust pipe which is provided vertically and a second exhaust pipe which links the first exhaust pipe with a treatment chamber are provided and a drain trap is provided beneath the first exhaust pipe. CONSTITUTION:The temperature of a uniformly heating region in a processing tube 10 is set at, for instance, 1000 deg.C by a heater 16. when steam and HCl gas are supplied to the processing tube 10 to subject a semiconductor wafer to an oxidation treatment, most parts of the steam and HCl gas are exhausted through the tube 10 and the steam is cooled on the inner wall of an exhaust pipe 22 which is provided vertically and drain containing HCl adheres to the inner wall of the exhaust pipe 22 and flows downward along the inner wall of the exhaust pipe 22 into a drain trap 40 and the drain is stored in a drain sink 42. If the level of the drain exceeds the level of holes 44, the drain overflows the drain sink 42 and is discharged from the drain trap 40. Therefore, however large the quantity of the drain is, the first exhaust pipe 22 and a second exhaust pipe 21 are not choked up by the drain, so that a desirable oxidation treatment which eliminates variation between the treated wafers can be realized.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a heat treatment apparatus.

(Prior art) In recent years, in the heat treatment process of semiconductor manufacturing, the size of processed wafers has increased from 4 inches to 6 inches and even 8 inches, and the number of wafers processed in batches has increased from 100 to 150. As the capacity increases, the amount of waste liquid as well as the exhaust gas discharged from heat treatment equipment such as oxidation and diffusion into the exhaust pipe is increasing.

Among heat treatment apparatuses, particularly in steam oxidation apparatuses, steam after wafer processing is cooled in an exhaust pipe, and a large amount of waste liquid adheres to the exhaust pipe.

Japanese Patent Application No. 63-21.1769 discloses a method for capturing reaction products contained in exhaust gas in an exhaust pipe.

For waste liquid treatment of semiconductor substrate processing equipment, see Japanese Patent Application Laid-Open No. 6
There is a publication No. 1-160933.

(Problem to be Solved by the Invention) In a steam oxidation device, a large amount of waste liquid adhering to the inside of the exhaust pipe accumulates in the exhaust pipe, and the opening of the exhaust pipe becomes substantially narrow, making it impossible to exhaust the inside of the processing container sufficiently, resulting in the desired heat treatment. However, there is an improvement in that the wafers that are processed in batches become more inconsistent.

Furthermore, it is necessary to periodically disassemble and clean the exhaust pipe, which reduces the operating rate of the heat treatment apparatus.

The former technique disclosed in the literature, which captures reaction products, cannot store a large amount of waste liquid, and therefore requires periodic disassembly and cleaning of the trap portion, which reduces the operating rate of the device. The technology in the latter document for waste liquid treatment cannot collect enough waste liquid in oxidizers etc. where a large amount of waste liquid adheres to the pipe wall in the exhaust pipe, and the waste liquid accumulates in the exhaust pipe, effectively closing the exhaust pipe opening. The same problem as above occurs. Furthermore, in equipment such as oxidation and diffusion, high temperature exhaust gas and HC
Since corrosive gases such as R are discharged, there are problems of deformation due to heat and corrosion due to gas.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a heat treatment apparatus that has a high operating rate with little variation among batch-processed wafers.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a heat treatment apparatus having a mechanism for exhausting exhaust gas after heat treatment through an exhaust pipe, including a first exhaust pipe section disposed perpendicularly to the exhaust pipe, and a first exhaust pipe section disposed perpendicularly to the exhaust pipe; A second exhaust pipe section connecting the pipe and the processing container is provided, and a waste liquid trap is provided below the first exhaust pipe section.

(Function) The present invention provides a first exhaust pipe section which is disposed perpendicularly to the exhaust passage and through which exhaust gas after heat treatment flows, and the waste liquid adhering to the inner wall of this exhaust pipe flows into the waste liquid trap. The waste liquid accumulated in the trap constantly overflows while maintaining the pressure difference between the inside of the exhaust pipe and the atmosphere, thereby preventing clogging of the exhaust pipe and making it possible to stabilize the process.

(Example) Hereinafter, an example in which the present invention is applied to a vertical oxidation furnace will be specifically described with reference to the drawings.

In FIG. 1, a vertical process tube 10 is made of a heat-resistant material, such as a quartz tube, and a process gas introduction pipe 12 is connected to one end of the tube.

A discharge pipe 13 is provided at the other end.

The exhaust pipe 13 is connected to a first exhaust pipe 22 in which the main cylinder is arranged vertically via a second exhaust pipe 21 arranged horizontally, and an exhaust fan is provided at the upper end of the first exhaust pipe 22. 20
are connected.

A cylindrical heater 16, for example, a resistance heater, is provided around the process tube 10.
can be appropriately set at a predetermined temperature, for example, in the range of 800°C to 1200°C.

In this process tube 10, a large number of wafers 18 are placed as objects to be processed, for example, in a wafer boat 17 made of quartz.
The boat 17 is stored horizontally on top, and the boat 17 is installed on a mounting table 19, and this mounting table 19 is installed on the lid body 14 and stored.

The lid 14 can be moved up and down by a lifting mechanism (not shown), and is configured so that the wafer 18 can be carried in and out of the process tube 10 at a predetermined position.

Steam from the steam generation source 2 and LC4 gas (from the mass flow controller 4) are supplied to the introduction pipe 12.

A waste liquid trap 40 is arranged below the connection point between the first exhaust pipe 22 and the second exhaust pipe 21. The details of this waste liquid trap 40 will be explained next with reference to FIG.

The first exhaust pipe 2 forming part of the waste liquid trap 40
A pipe 43 extending from No. 2 is inserted inside the liquid reservoir 42, and a plurality of holes 44 are provided in the upper part of the liquid reservoir 42, so that the waste liquid 48 overflows from the holes 44. However, the periphery of the liquid reservoir 42 is sealed with an outer case 46.

Piping 43 that comes into contact with corrosive gas such as high temperature gas and ICρ
The portion is made of a heat-resistant and corrosion-resistant material such as non-metallic material such as quartz or fluororesin.

The liquid reservoir 42 and the outer case 46 are also made of corrosion-resistant materials.

Next, the operation of the apparatus of the above embodiment will be explained.

When the soaking area in the process tube 10 is set to a temperature of, for example, 1000°C using the heater 16 and water vapor and H4 gas are supplied to the process tube 10 to perform oxidation treatment on semiconductor wafers, most of the water vapor and H4 gas are The water vapor is exhausted through the process tube 10 and cooled on the inner wall of the vertically arranged exhaust pipe 22, and the waste liquid containing HCQ adheres to the inner wall of the exhaust pipe 22 and falls along the inner wall of the exhaust pipe 22. The waste liquid flows into the waste liquid trap 40 and is stored in the liquid reservoir 42.If necessary, a cooling means may be provided in the outer atmosphere of the exhaust pipe 22.The waste liquid accumulated above the hole 44 overflows from the liquid reservoir 42. and discharged from the waste liquid trap 40.

Since the horizontally arranged exhaust pipe 21 has a temperature of 100° C. or higher, no waste liquid adheres thereto.

Therefore, no matter how much waste liquid there is, the first
The exhaust pipe 22 and the second exhaust pipe 21 are not blocked, and the desired oxidation process can be performed without variation among processed wafers.

In addition, since the waste liquid accumulated in the waste liquid trap 40 is configured to always overflow while maintaining the pressure difference between the inside of the exhaust pipe and the atmosphere, the waste liquid can be constantly circulated without stopping the oxidizer.

Therefore, since waste liquid does not accumulate in the exhaust pipes 21 and 22, there is no need to periodically disassemble and clean the exhaust pipes 21 and 22, and the operating rate of the oxidizer does not decrease.

In addition, even if waste edible gas such as HCQ is passed, the waste liquid trap 4
0 is constructed from non-metallic corrosion-resistant members, so corrosion does not occur.

Further, even if high-temperature exhaust gas is flowed, the waste liquid trap 40 is made of quartz, fluororesin, or the like, so problems such as thermal deformation do not occur. The material of the waste liquid trap 40 has a temperature of 1
Depending on the temperature, di-fluorinated resin may be used at temperatures below 40°C, tetra-fluorinated resin may be used at temperatures between 140 and 260°C, and quartz may be used at temperatures above 260°C.

Since the temperature of the outer case 46 is 100° C. or lower, if transparent vinyl chloride resin is used, it is possible to visually check the state of waste liquid accumulation. When the temperature of the exhaust pipe 21 becomes 100°C or less, waste liquid will adhere to it. Therefore, the exhaust pipe 21 connected to the process tube 10 is tilted slightly downward with respect to the waste liquid trap 40, and the waste liquid adhering to the exhaust pipe 21 is removed. It is desirable that all of the liquid is collected in the waste liquid trap 40.

Note that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the gist of the present invention. Of course, the shape of the waste liquid trap may be a U-shaped pipe or the like.

In the above embodiment, a steam oxidation furnace was explained, but it may be applied to heat treatment equipment such as a diffusion furnace or normal pressure CVC equipment, or other batch processing equipment, and the exhaust gas flowing in the exhaust pipe is not limited to steam. Of course, a processing gas may also be used. It goes without saying that the present invention can be applied not only to vertical devices but also to horizontal devices such as horizontal heat treatment furnaces.

〔Effect of the invention〕

As explained above, according to the present invention, waste liquid does not accumulate in the exhaust pipe and the exhaust pipe does not become substantially narrow, so there is no variation between processed wafers during processing, and the equipment can be operated at all times without stopping. This has the remarkable effect of improving the operating rate of the device since waste liquid can be discharged.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of one embodiment of the vertical heat treatment apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing an enlarged view of the waste liquid trap section of FIG. 1. 10...Process tube 16...Heater】8...
・Wafer 20 ・・Exhaust fan 21 2nd
Exhaust pipe 22...first exhaust pipe 40, waste liquid trap 42, liquid reservoir 44...hole

Claims (1)

[Claims] In a heat treatment apparatus having a mechanism for exhausting exhaust gas after heat treatment through an exhaust pipe, a first exhaust pipe section is arranged perpendicularly to the exhaust pipe, and a second exhaust pipe connects the exhaust pipe and the processing container. A heat treatment apparatus characterized in that a waste liquid trap is provided below the first exhaust pipe section.