JPH0745531A - Heat treatment equipment - Google Patents

Abstract

PURPOSE:To facilitate the detaching work of a quartz tube from a process vessel which tube accommodates a temperature measuring means, and improve the temperature measurement precision of an object to be treated. CONSTITUTION:In a heat treatment equipment provided with a process vessel 26 for heat-treating an object W to be treated, a lid body 40 of the object W in the process vessel 26, and a temperature measuring means for measuring the temperature in the process vessel 26, a quartz tube 50 accommodating the temperature measuring means is almost vertically retained to be detachable in the process vessel 26 through a hole 40 formed in the lid body 40, and a retaining means 54 for maintaining the airtightness of the process vessel 26 is installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus for performing heat treatment on an object to be processed such as a semiconductor wafer.

[0002]

2. Description of the Related Art In a heat treatment apparatus, for example, a CVD apparatus for forming a film on the surface of a semiconductor wafer, for example, a boat carrying a large number of wafers is carried into a vertical processing container and hermetically sealed so that the inside of the processing container is predetermined. A vacuum is evacuated to a degree of vacuum, and then a reaction gas is introduced into the processing container to form a film by CVD under heating. Such a conventional heat treatment apparatus is disclosed in, for example, Shokai Sho 6
JP-A-3-121431 and JP-A-4-162517.
It is disclosed in Japanese Patent Publication No.

Into the processing container applied to the above heat treatment apparatus, various introduced members necessary for executing the processing are introduced and arranged in the processing container. As this type of member to be introduced, an injector for supplying a reaction gas is used.
Besides, thermocouples for measuring the temperature of each heating zone in the vertical direction of the processing container are generally known. by the way,
In the conventional heat treatment apparatus, as shown in FIG. 5, a thermocouple a for temperature measurement is introduced from the lower end of the processing container c in a state of being accommodated in an introduction tube b made of quartz, and is vertically oriented toward the upper end. Arranged in the direction. The base end of the introduction tube b extends outside from the lower end of the processing container c, and the introduction tube b is introduced.
A cable e of a thermocouple, which is fixed to the base end opening of the sleeve b with a rubber cap d or the like, is connected to a temperature measuring device (not shown). That is, as shown in FIG. 5, the conventional thermocouple introduction tube b is formed in a substantially L shape composed of a long vertical portion f and a relatively short horizontal portion g.

[0004]

Conventionally, in the case of a CVD furnace, the above-mentioned thermocouple introduction tube (hereinafter referred to as T / C tube) has an outer reaction tube and an inner reaction tube which constitute the above-mentioned processing container. And is pushed into the outer wall of the processing vessel in the case of an oxidation furnace. However, the work of attaching and removing the T / C tube b is complicated, and the distance between the object to be processed housed in the boat in the processing container and the T / C tube b is long. However, there is a problem that it is difficult to perform accurate temperature control because the temperature of the processing object accommodating portion is different from the temperature of the measurement region. Although the method of inserting the T / C tube into the processing container and measuring the temperature inside the container before the processing has already been carried out, the T / C tube is kept inside the processing container during the heat treatment. The temperature control performed by arranging vertically is not carried out due to the difficulty of maintaining the airtightness in the processing container and the vertical support of the T / C tube. An object of the present invention is to facilitate the attachment / detachment work of the quartz tube accommodating the temperature measuring means to / from the processing container and to improve the temperature measurement accuracy of the object to be processed.

[0005]

According to the present invention, there is provided a processing container for heat-treating an object to be processed, a boat for supporting the object to be processed in the processing container, and a container for holding the boat. In a heat treatment apparatus equipped with a lid capable of sealing a processing container and a temperature measuring means for measuring the temperature in the processing container, a quartz tube containing the temperature measuring means is formed in the lid. And a tube supporting means for holding the airtightness inside the processing container while detachably supporting the same in the processing container almost vertically. Therefore, the quartz tube containing the temperature measuring means is arranged in the vicinity of the object to be processed during the heat treatment, and the temperature in the vicinity of the object to be processed during the heat treatment is accurately measured. Further, the detachable support means facilitates attachment / detachment, replacement and cleaning of the quartz tube.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vertical heat treatment apparatus for semiconductor wafers to which the heat treatment apparatus of the present invention is applied will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of a vertical heat treatment apparatus equipped with a T / C tube according to an embodiment of the present invention, specifically, a CVD apparatus. As shown in FIG. 1, an I / O port 4 for loading and unloading a carrier C accommodating, for example, 25 semiconductor wafers W is provided in the front part of the housing 3 of the heat treatment apparatus 2. A posture changing mechanism 6 for changing the posture of the wafer W together with the carrier C by 90 degrees is provided below the / O port 4. Behind the I / O port 4, a carrier transfer mechanism 8 that receives and conveys the carrier C from the attitude conversion mechanism 6 is arranged, and the robot arm 9 of the carrier transfer mechanism 8 is operated by the carrier elevator 12. It is constructed so that it can move up and down and expand and contract in the front-back direction.

Further, a transfer stage 10 is provided further behind the I / O port 4, and the transfer stage 10 is constructed so as to be able to hold the carriers C in two upper and lower stages. A carrier stocker 14 is provided above the transfer stage 10.
The carrier supporter 15 is provided in the carrier stocker 14 so that a maximum of eight carriers C can be stored at one time. The carrier stocker 14
At the rear of the heat treatment furnace 24, a heat treatment furnace 24 containing a processing container 26 is disposed, and a shutter 22 for opening and closing a lower end opening of the heat treatment furnace 24 is rotatably provided. Below the heat treatment furnace 24, a wafer boat 18 capable of accommodating, for example, 200 wafers at a time is provided so as to be able to move up and down by a boat elevator 20. Between the wafer boat 18 and the transfer stage 10, there is provided a transfer device 16 having five tweezers so that, for example, five wafers can be transferred at one time.

In the heat treatment apparatus 2 thus constructed,
For example, the carrier C accommodating 25 wafers W
The carrier C is placed on the posture changing mechanism 6 in the O port 4, the posture of the carrier C is changed by 90 degrees by the posture changing mechanism 6, and then the carrier C is carried into the transfer stage 10 by the carrier transfer mechanism 8. The carrier is transferred to the carrier stocker 14 by the carrier elevator 12.
Then, the wafer W in the carrier C on the transfer stage 10
Are transferred to the wafer boat 18 by the transfer device 16. Wafer boat 18 containing a predetermined number of wafers W
Is raised by the boat elevator 20, and at the same time, the shutter 22 is opened and inserted into the furnace from the lower end opening of the heat treatment furnace 24. After that, the shutter 22 is closed, and the wafer W is heat-treated in the heat treatment furnace 24 by heater heating. Then, after the predetermined heat treatment is completed, the wafer boat 18 descends and moves from the heat treatment furnace 24 to the original position. Wafer boat 1 after a predetermined time
The wafer W on 8 is transferred by the transfer device 16 to the transfer stage 1
Returned to Carrier C on 0.

Since the heat treatment apparatus of this embodiment is a batch process, although not shown, support grooves for stacking a large number of wafers W are formed on the wafer boat 18 or the carrier C at a constant pitch and spaced from each other. Has been done. Next, a specific configuration of the heat treatment furnace according to this embodiment will be described.
As shown in FIG. 2, the heat treatment furnace 24 includes a processing container 26 and a heating unit. The processing container 26 is provided with a manifold 32 to be described later, an outer reaction tube 26 that is formed into a cylindrical shape from, for example, quartz glass, and has an upper end closed and a lower end open. And a cylindrical inner reaction tube 30 of which upper and lower ends are made of, for example, quartz and which are open, are formed into a double tube structure. The inner reaction tube 30 can accommodate a wafer boat 18 in which a large number of semiconductor wafers W are stacked and mounted. The wafer boat 18 is also made of quartz.

On the outer circumference of the outer reaction tube 28, a resistance heating heater 44 is coaxially provided so as to surround the outer reaction tube 28, and a heat insulating material 46 is provided on the outer circumference of the heating heater 44.
A tubular outer shell 36 made of, for example, a stainless steel is provided through the heat treatment furnace 24 as a whole.
Are configured. The inside of the processing container 26 is controlled by the heating heater 44 so that the heating temperature is, for example, 3
It can be appropriately set in the range of 00 to 1200 ° C. by a predetermined processing program. The outer reaction tube 2
At the lower end of 8, a cylindrical manifold 32 made of, for example, stainless steel is connected.
An annular flange portion 33 is formed at the upper end of 2, and an O-ring 35 as a seal member is inserted in the annular groove of the flange portion 33 to connect the outer reaction tube 28 and the manifold 32. The space between them is hermetically sealed. The manifold 32 supports the lower end of the inner reaction tube 30, while a gas introduction pipe 37 for supplying a processing gas is connected to the lower part of one side and an external vacuum pump 39 is connected to the upper part of the opposite side.
The exhaust pipe 41 connected to the processing container 2 is connected.
The inside of 6 is evacuated, and then the reaction gas is introduced.

The wafer boat 18 is placed on an upper portion of a heat retaining cylinder 38 made of, for example, quartz.
Is rotatably supported by a lid 40 made of, for example, a stainless steel. The lid 40 is configured to hermetically seal the lower end opening of the manifold 32 via the O-ring 43. The lid 40 is installed on the boat elevator 20 so that the wafer boat 18 can be loaded and unloaded into the processing container 26. Further, the wafer boat 18 and the heat insulating cylinder 38 are configured to rotate at a predetermined speed by the rotary drive mechanism 53 mounted on the lid 40. The gas introducing pipe 37 is bent in an L shape by quartz or the like, and is connected to an external gas pipe 45 made of, for example, a stainless steel at a penetrating portion of the manifold 32. The gas pipe 45 is connected to an external gas supply source 47, for example, a CVD reaction gas supply source. In the heating heater 44, the processing space 34 in the processing container 26 is divided into 5 zones in the vertical direction, and each of them is heated under a suitable temperature condition.
The zone system is adopted.

Next, T / according to the first embodiment of the present invention
The C-tube and its support mechanism will be described. As shown in FIG. 3, the T / C tube 50 is made of quartz, and accommodates five pairs of thermocouples 51 inside, which corresponds to the heating heater 44 of the five-zone system. The film forming process temperature is accurately detected. Then, the lead wire of each thermocouple 51 is connected to a temperature measuring device 52 (see FIG. 2) arranged outside the heat treatment apparatus, and although not shown, 5
The circuit is configured so as to perform feedback control on each heater of the memory. Further, an automatic control system by a computer (not shown) is connected to the feedback system.

A flange 55 is provided at the lower end of the T / C tube 50. An annular groove 56 is formed on the upper surface of the flange 55, and an O-ring 58 is mounted in the annular groove 56. On the other hand, on the lower surface of the lid 40,
A circular recess 60 is formed at a position where it does not interfere with the moving direction of the transfer device 16 during wafer transfer, and a through hole 62 is formed therein. Then, the T / C tube 50 is inserted through the through hole 62, and the upper surface of the flange portion 54 is recessed 60.
The T / C tube 50 is positioned vertically with respect to the lid body 40 by being brought into close contact with the lower surface of the lid body 40. Then, the T / C tube 50 is detachably attached to the lid body 40 by screwing a plurality of setscrews 64 into a female screw 66 formed in the flange 40 through a plurality of holes formed in the flange 55. It is supposed to stick. First as above
A support mechanism 54 for the T / C tube 50 in the embodiment is constructed.

The set screw 64 is constructed such that a Teflon washer 68 is inserted between the knurled screw head and the lower surface of the flange 54 and fixed by hand. Also, 5 inserted in the T / C tube 50
The lower ends of the paired thermocouples are bundled into a cable 70,
It is connected to a temperature measuring device 52 outside the processing container. By using the support mechanism of the T / C tube 50 configured as described above, the T / C tube 50 can be attached and fixed to the lid body 40 vertically with great accuracy by the flange 54. Moreover, since the mounting is performed by hand-tightening a plurality of bolts, it is extremely easy and can be removed in a short time.

Next, T / according to the second embodiment of the present invention.
The C-tube and its support mechanism will be described. As shown in FIG. 4, in this embodiment, a metallic guide member 72 is fixed by welding or the like in a through hole 62 formed in the lid 40, and the inner hole of the guide member 72 has a predetermined length. A first O-ring 74 mounted on the upper end of the inner hole and a second O-ring 78 separated by a predetermined distance via a Teflon washer 76.
Thus, the T / C tube 50 is vertically supported with respect to the lid 40 by two-point support. And the second
The O-ring 78 is supported and fixed by a cap screw 82 via a press washer 80, and by rotating the cap screw 82, the press washer 80 rises and by the guide member 72, the Teflon washer 76, and the press washer 80, The first and second O-rings 74 and 78 are crushed to elastically grip and fix the T / C tube 50. As described above, the support mechanism 71 for the T / C tube 50 in the second embodiment is constructed.

The five pairs of thermocouples inserted in the T / C tube 50 are bundled at their lower ends to form a cable 70 as in the first embodiment, and an external temperature measuring device is provided. It is connected to 52. When the T / C tube support mechanism according to the second embodiment having the above-described structure is used, the T / C can be extremely accurately held by pressing and holding the two O-rings 74 and 78.
The tube 50 can be attached and fixed vertically to the lid 40. Moreover, since the mounting is performed by hand-tightening the cap screw 82, it is extremely easy and can be removed in a short time. Further, when the T / C tube 50 is erected on the lid body 40 as described above, the T / C tube 50 is formed during the heat treatment.
Since they can be supported laterally close to each other, the temperature closest to the temperature received by the object to be processed during the heat treatment can be accurately measured in real time without contact.

Next, the CV in the furnace in the above heat treatment apparatus
The D process will be described with reference to FIG. First, the wafer boat 18 in which a large number of semiconductor wafers W are accommodated at a predetermined pitch is loaded into the processing container 26 by the boat elevator 20, and the opening of the manifold 32 is closed by the lid 40. The inside of the processing container 26 is sealed. Then, while supplying a predetermined amount of processing gas such as TEOS from the gas introduction pipe 37, the inside of the processing container 26 is evacuated by the vacuum pump 39 through the exhaust pipe 41 to a predetermined pressure, for example, 1T.
Set to orr. Further, while maintaining the inside of the reaction tube at a predetermined temperature, for example, 400 ° C. by the heating heater 44, the above TEOS is supplied at, for example, about 100 cc / min, and nitrogen gas as a carrier gas is supplied at about 20 liters / min for a predetermined time. Perform membrane treatment. During the film formation process, the semiconductor wafer W is rotated by rotating the wafer boat 18 at a predetermined speed by the rotation drive mechanism 53. Then, during the film forming process, the gas introduction pipe 3
The processing gas introduced from 7 is rectified when it is discharged into the processing container from the tip discharge port of the gas introduction pipe 37 and rises as a laminar flow, and a part of the processing gas is transferred to the semiconductor wafer W.
It flows to the side, and a desired uniform film is formed on the entire surface of the semiconductor wafer.

In the present invention, the T / C tube 50 is vertically held in the vicinity of the wafer boat 18 during such film formation.
Since the temperature near the wafer during film formation can be measured and the heating heater 44 can be feedback-controlled based on the measured value, the temperature inside the furnace during film formation can be kept uniform. If the film forming process is repeated, a film is formed on the outer surface of the T / C tube and the thermal conductivity deteriorates.
The tube needs to be cleaned regularly. However, even in that case, according to the present invention, the T / C tube is extremely easily attached to and detached from the lid body, so that the T / C tube can be detached or replaced in a short time for cleaning. The embodiment in which the invention is applied to the CVD apparatus for semiconductor wafers has been described above, but the invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the invention. . For example, the present invention can be applied to an oxidation furnace, a diffusion furnace, an etching device, an ashing device, a CVD device for LCD substrates, and the like.

[0019]

As described above, according to the present invention,
The temperature in the furnace during the reaction process can be accurately measured, and the quartz tube accommodating the temperature measuring means can be easily attached and detached, so that the quartz tube can be easily washed and replaced. Furthermore, in the heat treatment apparatus according to the fourth aspect, the temperature of the object to be processed during the reaction process can be maintained uniform.

[Brief description of drawings]

FIG. 1 is a perspective view showing the overall configuration of a heat treatment apparatus of the present invention.

FIG. 2 is a vertical sectional view showing the structure of a heat treatment furnace according to an embodiment of the present invention.

FIG. 3 is a sectional view of a T / C tube support mechanism according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a T / C tube support mechanism according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a conventional T / C tube mounting mechanism.

[Explanation of symbols]

 W semiconductor wafer (object to be processed) 2 heat treatment apparatus 18 wafer boat 26 processing container 40 lid 50 T / C tube (quartz tube) 51 thermocouple (temperature measuring means) 53 rotary drive mechanism 54, 71 support Mechanism (supporting means) 55 Flange 62 Through hole 74, 78 O-ring

Claims (4)

[Claims] 1. A processing container for heat-treating an object to be processed, a boat for supporting the object to be processed in the processing container, and a lid for holding the boat and sealing the processing container. In a heat treatment apparatus equipped with temperature measuring means for measuring the temperature in the processing container, a quartz tube accommodating the temperature measuring means is attached and detached substantially vertically in the processing container through a hole formed in the lid. A heat treatment apparatus, which is provided with supporting means for supporting the airtightness of the inside of the processing container while supporting it as much as possible. 2. The heat treatment apparatus according to claim 1, wherein the supporting means comprises a flange provided on a base portion of the quartz tube. 3. The heat treatment apparatus according to claim 1, wherein the supporting means comprises a double O-ring that holds the base of the quartz tube. 4. The heat treatment apparatus according to claim 1, further comprising a rotation drive mechanism for rotating the boat in the processing container.