JPH08170176A - Vapor-phase chemical reactor - Google Patents

Abstract

PURPOSE: To maintain the uniformity in thickness distribution of a formed film by providing a mechanism to monitor the heat radiation rate of the face of a shower head opposed to a wafer and cleaning the head face at an opportune moment in consideration of the change in the heat radiation rate. CONSTITUTION: A sensor 101 for monitoring the heat radiation rate of a shower head 2 is provided at the several points on both side faces of the orifice plate 22 of the head 2 opposed to a wafer 4 to monitor the change in heat radiation rate of the orifice plate 22 and the optical change of the surface. A composite element of the integrated light emitting and receiving elements is used as the sensor 101. Consequently, when the face of the orifice plate 22 opposed to the wafer 4 is clean, the emitted light is radiated into a space, and only the least light returns to the light receiving elements. Meanwhile, when the face is contaminated, a large quantity of light emitted in proportion to the amt. of contaminant stuck to the sensor 101 face is returned and received by the element, and a change in the state of the face of the orifice plate 22 opposed to the wafer 4 is recognized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to uniformity of film thickness distribution in semiconductor manufacturing, particularly when a film is formed by using vapor deposition.

[0002]

2. Description of the Related Art A vapor phase chemical reaction apparatus, for example, in a thin film manufacturing apparatus used for manufacturing a semiconductor, (1) uniformity of film thickness and (2) ) Uniformity of the composition of the film is important, and in order to obtain this uniformity, stable control of the supply of the source gas, the temperature of the wafer and other film forming conditions is very important.

As an example of a vapor phase chemical reaction apparatus, a chemical vapor deposition apparatus disclosed in Japanese Utility Model Laid-Open No. 3-109329 will be taken up as an example and described below. FIG. 5 is a sectional view of the device.

An operation for forming a film will be described. After introducing the wafer 4 onto the susceptor 3 in the vacuum container 5, the gas in the vacuum container 5 is evacuated through the vacuum exhaust port 51. Next, an inert gas is introduced into the vacuum container 5 through the first gas supply pipe 71 and the shower head 2. When the vacuum container 5 reaches a certain pressure, stop the gas supply, and
The gas in the vacuum container 5 is evacuated through the vacuum exhaust port 51. After repeating this process several times to replace the gas in the vacuum container 5, the gas in the vacuum container 5 is evacuated to a vacuum exhaust port 51.
Evacuate via. Next, the reaction gas is supplied to the shower head through the first gas supply pipe 71. The raw material gas passes through the orifice plate 22 and is supplied to the wafer 4 which is placed on the susceptor 3 in the vacuum container 5 and heated by the heater 31. The gas not consumed in the vapor phase growth and the gas generated by the reaction are evacuated via the evacuation pipe 51.

After that, the supply of the reaction gas is stopped and the gas in the vacuum container 5 is evacuated through the evacuation port 51. Next, the inert gas is introduced into the vacuum container 5 from the first gas supply pipe 71 through the shower head 2. Vacuum container 5
When the pressure reaches a certain level, stop the gas supply and
The gas in the vacuum container 5 is evacuated via the evacuation port 51. This process is repeated several times to replace the gas in the vacuum container 5. After introducing an inert gas into the vacuum container 5 from the first gas supply pipe 71 to adjust the pressure to atmospheric pressure, the susceptor 3
The upper wafer 4 is carried out of the vapor phase chemical reaction device 1.

A problem with the prior art when the shower head 2 is opposed to the heated wafer 4 at a relatively short distance is that the raw material gas not deposited on the wafer 4 is the orifice plate 22 of the shower head 2. That is, the film is formed on the surface facing the wafer 4 and the thermal emissivity of the surface changes.
As a result, the heat flux absorbed from the wafer 4 to the orifice plate 22 changes, and the temperature distribution of the wafer 4 on the heat supply side deviates from a predetermined value, resulting in fluctuations in the film thickness of the film formed. In the known example, cooling water is introduced into the shower head 2 to forcibly cool the shower head 2 to suppress the film formation on the orifice plate 22 by the unreacted source gas, thereby attempting to solve this problem. However, the orifice plate 22
It is not enough to suppress the adhesion of the film by lowering the temperature of the film. Since the film formation speed is slowed but the adhesion is not completely eliminated, the thermal emissivity of the orifice plate 22 is made constant constantly. It's difficult. Therefore, the surface of the orifice plate 22 needs to be cleaned in some way, but there is a problem that it is difficult to maintain the uniformity of the film thickness because there is no means for appropriately determining this time in the conventional technology.

[0007]

The prior art has a problem that it is difficult to maintain the uniformity of the film thickness because there is no means for appropriately determining the cleaning time of the orifice plate 22 of the shower head 2.

[0008]

Means for Solving the Problems In order to maintain the uniform film forming performance which is the above-mentioned object, means for appropriately determining the cleaning time of the orifice plate 22 of the shower head 2 is provided in the orifice plate 22 portion. This is accomplished by monitoring changes in the emissivity of 22 and thereby determining when to clean the orifice plate 22. The means is the orifice plate 2
The shower head thermal emissivity sensor 101 for measuring the thermal emissivity of the surface of the second wafer 4 facing the wafer 4 is provided on the orifice plate 22, and the change of this signal is constantly monitored to determine the cleaning time of the orifice plate 22. As a result, the orifice plate 22 can be cleaned at an appropriate time, so that the uniformity of the film thickness can be maintained for a long period of time.

[0009]

The sensor 1 for monitoring the emissivity of the shower head detects changes in the heat emissivity of the surface of the orifice plate 22 facing the wafer 4.
Since the orifice plate 22 can be cleaned at a proper time by constantly monitoring with 01, the orifice plate 22 can be cleaned at an appropriate time, so that the uniformity of the film thickness can be maintained for a long period of time.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing an embodiment of the present invention.

In FIG. 1, 1 is a gas phase reactor, 2 is a shower head, 3 is a susceptor, 4 is a wafer, 5 is a vacuum container,
6 is a vacuum exhaust unit, 7 is a gas supply unit, 8 is a gas processing unit, and 9 is a gas processing unit.
Is a spare chamber, 10 is a vacuum gauge, 21 is a gas mixing chamber, 22 is an orifice plate, 31 is a heater, 51 is a vacuum exhaust port, 61 is a vacuum exhaust pipe, 62 is a vacuum exhaust valve, 63 is a showerhead exhaust pipe, and 64 is Shower head exhaust valve, 7
1 is a first gas supply pipe, 72 is a second gas supply pipe, 81
Is a gas processing pipe, 82 is an exhaust pipe, 91 is a preliminary chamber first gate valve, 92 is a preliminary chamber second gate valve, 93 is a wafer handler, 100 is a shower head heat radiation rate monitoring controller, and 101 is a shower head heat. Emissivity monitoring sensor, 102 sensor cable, 200 cooling unit,
Reference numeral 201 denotes a vacuum container bottom cooling water supply pipe, 202 denotes a vacuum container bottom cooling water recovery pipe, 203 denotes a vacuum container side cooling water supply pipe, 204 denotes a vacuum container side cooling water recovery pipe, 205 denotes a shower head cooling water supply pipe, 206 Is a showerhead cooling water recovery pipe, 207 is a showerhead cooling duct, and 208
Is a cooling container side cooling duct, and 209 is a vacuum container bottom cooling duct.

The operation of the present invention will be described below. In the present embodiment, the case where there are two source gas supply pipes will be described. The procedure for forming the film is as follows.

After the wafer 4 is introduced onto the susceptor 3 in the vacuum container 5, the gas in the vacuum container 5 is evacuated using the vacuum exhaust unit 6 via the vacuum exhaust pipe 61. Next, an inert gas is supplied from the gas supply unit 7 through the first gas supply pipe 71 and the second gas supply pipe 72 through the shower head 2 to the vacuum container 5
To be introduced. When the vacuum container 5 reaches a predetermined pressure, the gas supply is stopped, and the gas in the vacuum container 5 is evacuated again using the vacuum evacuation unit 6 via the vacuum evacuation pipe 61.
This process is repeated several times to replace the gas in the vacuum container 5, and then the gas in the vacuum container 5 is vacuum-exhausted in the vacuum exhaust unit 6 via the vacuum exhaust pipe 61.

Next, the reaction gas is supplied from the gas supply section 7 to the gas mixing chamber 21 through the first gas supply pipe 71 and the second gas supply pipe 72. The raw material gases supplied from the first gas supply pipe 71 and the second gas supply pipe 72 in the gas mixing chamber 21 are mixed in the mixing chamber 21, pass through the orifice plate 22, and are arranged on the susceptor 3 in the vacuum container 5. The wafer 4 thus formed is supplied and film formation is performed.

After that, the gas in the vacuum container 5 is evacuated using the evacuation unit 6 through the evacuation pipe 61.
Next, an inert gas is supplied from the gas supply unit 7 to the first gas supply pipe 7
1, the gas is introduced into the vacuum container 5 from the second gas supply pipe 72 through the shower head 2. When the vacuum container 5 reaches a predetermined pressure, the gas supply is stopped, and the gas in the vacuum container 5 is evacuated again using the vacuum evacuation unit 6 via the vacuum evacuation pipe 61. This process is repeated several times to replace the gas in the vacuum container 5. The wafer 4 on the susceptor 3 is replaced with a new wafer 4 placed in the spare chamber 9. This is the cycle of a gas phase chemical reactor.

During this time, a change in the thermal emissivity of the orifice plate 22, that is, the optical state of the surface is changed by the shower head thermal emissivity monitoring sensor 101 provided at several places on the surface of the orifice plate 22 of the shower head 2 facing the wafer 4. Are being monitored for changes. In this case, the thermal emissivity monitoring sensor 10
1 is composed of a composite element in which a light emitting element and a light receiving element are integrated, and if the surface of the orifice plate 22 facing the wafer 4 is very clean, the light emitted from the thermal emissivity monitoring sensor 101 is a space. Is emitted to the light receiving element and only a very small amount of light returns to the light receiving element. However, if the surface of the orifice plate 22 facing the wafer 4 is contaminated for some reason, the surface of the showerhead thermal emissivity monitoring sensor 101 is also contaminated, so the emitted light is contaminated on the surface of the thermal emissivity monitoring sensor 101. Many things will be reflected back for themselves because of the reflection of things. Since the amount of returned light is proportional to the amount of contamination on the surface of the orifice plate 22 facing the wafer 4, if the amount of light received by the thermal emissivity monitoring sensor 101 is constantly monitored, the wafer 4 of the orifice plate 22 will be affected. The change in the state of the surface facing the can be known. That is, the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 can be constantly monitored.

As described above, the shower head thermal emissivity monitoring sensor 101 can constantly monitor the change in the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 to determine the cleaning time of the orifice plate 22. Since it is possible to decide to wash the orifice plate 22 at a certain time, the uniformity of the film thickness can be maintained for a long period of time.

FIG. 2 is a block diagram of another embodiment of the present invention. In this embodiment, the thermocouple 103 embedded in the orifice plate 22 is used to monitor the change in the thermal emissivity of the surface of the orifice plate 22 of the shower head 2 facing the wafer, that is, the change in the optical state of the surface.

If the surface of the orifice plate 22 facing the wafer 4 is very clean, the thermal emissivity of the orifice plate 22 is small, so the amount of heat radiated from the wafer 4 that flows into the orifice plate 22 is small. is there. Therefore, most of it is reflected by the orifice plate 22 again and returns to the wafer side. However, if the surface of the orifice plate 22 facing the wafer 4 is contaminated for some reason, the embedded surface of the thermocouple 103 is also contaminated, so that the thermal emissivity becomes large. Therefore, more heat radiated from the wafer 4 flows into the orifice plate 22 than in a clean state. Therefore, the amount of heat reflected back to the wafer 4 by the orifice plate 22 is reduced. The temperature of the orifice plate 22 rises due to the increased amount of heat flowing into the orifice plate 22. The temperature rise of the orifice plate 22 has a correlation with the amount of contamination attached to the embedded surface of the thermocouple 103. Therefore, if the temperature rise of the thermocouple 103 is constantly monitored, the wafer 4 of the orifice plate 22 is The change in the state of the surface facing the can be known. That is, the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 can be constantly monitored.

As described above, it is possible to determine the cleaning time of the orifice plate 22 by constantly monitoring the change in the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 with the thermocouple 103.
Since it is possible to decide to wash the orifice plate 22 at an appropriate time, the uniformity of the film thickness can be maintained for a long period of time.

FIG. 3 is a block diagram of another embodiment of the present invention. In the present embodiment, the showerhead thermal emissivity monitoring embedded in the orifice plate 22 for monitoring the change of the thermal emissivity of the surface of the orifice plate 22 of the showerhead 2 facing the wafer, that is, the change of the optical state of the surface. Although the sensor 101 for use is used, the thermocouple 103 shown in FIG. 2 may be used. In this embodiment, high-frequency plasma is used as a cleaning mechanism for maintaining the thermal emissivity of the surface of the orifice plate 22 of the shower head 2 facing the wafer 4 at a constant value based on the monitoring result. In this embodiment, the high-frequency plasma generating mechanism is composed of a high-frequency power supply unit 300, a high-frequency power supply line 301, an orifice plate 22 as an electrode and a susceptor 3.

This cleaning mechanism is used when it is determined that the heat emissivity of the surface of the orifice plate 22 facing the wafer, which is monitored by the shower head heat emissivity monitoring sensor 101, is significantly deteriorated as compared with a clean state. Is the orifice plate 22
Then, plasma is generated in the space surrounded by the surface of the susceptor 3 on which the wafer 4 is mounted, and the surface of the orifice plate 22 facing the wafer is cleaned by the plasma.

Here, a case where the wafer 4 is not placed on the susceptor 3 will be described. The gas in the vacuum container 5 is evacuated using the evacuation unit 6 via the evacuation pipe 61. Next, an inert gas is introduced into the vacuum container 5 from the gas supply unit 7 through the first gas supply pipe 71 and the second gas supply pipe 72 through the shower head 2. When the vacuum container 5 reaches a certain predetermined pressure, the supply of gas is stopped, and the gas in the vacuum container 5 is again evacuated using the vacuum evacuation unit 6 via the vacuum evacuation pipe 61. This process is repeated several times and the vacuum container 5
After the gas inside is replaced, the gas inside the vacuum container 5 is evacuated by the evacuation unit 6 via the evacuation pipe 61.

Next, a reaction gas for cleaning with plasma is supplied from the gas supply unit 7 to the gas mixing chamber 21 through the first gas supply pipe 71 and the second gas supply pipe 72. In the gas mixing chamber 21, the first gas supply pipe 71 and the second gas supply pipe 7
The raw material gas supplied from No. 2 is mixed in the mixing chamber 21 and then supplied into the vacuum container 5 through the orifice plate 22. When the pressure in the vacuum container 5 reaches a predetermined pressure for generating plasma, the high frequency power generated by the high frequency power supply 300 passes through the power supply line 301 and is the electrode of the orifice plate 22.
Is supplied to the susceptor 3 and plasma is generated. After cleaning with plasma for a predetermined time, the supply of high frequency is stopped. Shower head Emissivity sensor 10
The heat emissivity of the surface of the orifice plate 22 facing the wafer monitored in 1 is measured to confirm that the cleaning is sufficiently performed. If insufficient, plasma cleaning is performed again, and the cleaning is repeated until the surface of the orifice plate 22 facing the wafer is sufficiently cleaned.

After that, the gas in the vacuum container 5 is evacuated using the vacuum exhaust unit 6 through the vacuum exhaust pipe 61.
Next, an inert gas is supplied from the gas supply unit 7 to the first gas supply pipe 7
1, the gas is introduced into the vacuum container 5 from the second gas supply pipe 72 through the shower head 2. When the vacuum container 5 reaches a certain predetermined pressure, the supply of gas is stopped, and the gas in the vacuum container 5 is again evacuated using the vacuum evacuation unit 6 via the vacuum evacuation pipe 61. This process is repeated several times to replace the gas in the vacuum container 5, and then the gas in the vacuum container 5 is vacuum-exhausted in the vacuum exhaust unit 6 via the vacuum exhaust pipe 61. After that, the wafer 4 is introduced into the vacuum container 5 to form a film.

As described above, the thermocouple 103 constantly monitors the change of the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4, and the cleaning time of the orifice plate 22 is determined. Therefore, the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 can be maintained constant.

FIG. 4 is a block diagram of another embodiment of the present invention. In the present embodiment, the showerhead thermal emissivity monitoring embedded in the orifice plate 22 for monitoring the change of the thermal emissivity of the surface of the orifice plate 22 of the showerhead 2 facing the wafer, that is, the change of the optical state of the surface. Although the sensor 101 for use is used, the thermocouple 103 shown in FIG. 2 may be used. In this embodiment, a heater control auxiliary signal output line 105 for correcting the temperature of the susceptor 3 based on the monitoring result is connected to the heater controller 32 from the shower head thermal emissivity monitoring controller 100.

If the thermal emissivity of the surface of the orifice plate 22 facing the wafer 4 becomes extremely large for some reason, the temperature uniformity of the wafer 4 placed on the susceptor 3 deteriorates. A signal for correcting the difference from the uniform temperature distribution of the wafer 4 expected from the monitoring result of the shower head thermal emissivity monitoring sensor 101 is sent from the shower head thermal emissivity monitoring controller 100 through the heater control auxiliary signal output line 105. And heater controller 32
Is output to. By this signal, the heater controller 3
2 sends the corrected electric power for temperature control to the heater 31 via the heater power supply line 33. This compensates for the temperature uniformity of the wafer 4.

As described above, the thermal emissivity of the shower head can be monitored, and the temperature of the susceptor can be corrected based on the monitoring result.

[0031]

According to the present invention, it is possible to constantly monitor the change in the thermal emissivity of the surface of the shower head facing the wafer, which greatly affects the uniformity of the temperature of the wafer, and the shower head can be monitored at an appropriate time. Since it is possible to determine the cleaning time of the surface facing the wafer, the uniformity of the film thickness can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a second embodiment of the present invention.

FIG. 3 is a block diagram of a third embodiment of the present invention.

FIG. 4 is a block diagram of a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Gas phase reaction apparatus, 2 ... Shower head, 3 ... Susceptor, 4 ... Wafer, 5 ... Vacuum container, 22 ... Orifice plate,
31 ... Heater, 51 ... Vacuum exhaust port, 71 ... First gas supply pipe, 205 ... Shower head cooling water supply pipe, 206 ...
Shower head cooling water recovery pipe, 207 ... Shower head cooling duct.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masato Ikegawa, 502 Jinritsucho, Tsuchiura-shi, Ibaraki, Institute of Mechanical Engineering, Hitate Manufacturing Co., Ltd. Semiconductor Division (72) Inventor Kazuhiko Matsuoka 111 Nishikote-cho, Takasaki-shi, Gunma Hitachi, Ltd. Semiconductor Division (72) Inventor Akira Yoshida 3-16-3 Higashi, Shibuya-ku, Tokyo Inside Hitachi Electronics Engineering Co., Ltd. (72) Inventor Takeshi Ogura, Hitachi Electronics Engineering Co., Ltd., 3-16-3 Higashi, Shibuya-ku, Tokyo

Claims (2)

[Claims] 1. A vacuum container, a susceptor arranged in the vacuum container, a wafer arranged on the susceptor, and a wafer temperature control for heating or cooling the wafer arranged on the susceptor. An apparatus, a shower head that faces the susceptor and supplies a reaction gas for causing a chemical reaction to the wafer; a gas supply unit that supplies the reaction gas to the shower head; the gas supply unit; A gas supply pipe for connecting the shower head, a gas mixing chamber for making the composition of the raw material gas ejected from the shower head uniform, a vacuum exhaust unit for exhausting the gas in the vacuum container, and A vacuum exhaust pipe that connects a vacuum container and the vacuum exhaust unit, a pressure adjusting valve for adjusting the pressure of the vacuum container, and the wafer on the susceptor. A transfer device for carrying out or carrying in, a preliminary chamber for carrying in or carrying out the wafer to a vacuum device, a gas processing unit for processing a reaction gas not consumed in the vacuum container, the gas processing unit and the above A gas phase chemical reaction device comprising a gas processing pipe connecting an evacuation unit, a shower head cooling mechanism for cooling the shower head, and a vacuum vessel wall surface cooling mechanism for cooling the wall surface of the vacuum vessel, wherein the shower head is provided. A vapor phase chemical reaction device comprising a mechanism for monitoring the thermal emissivity of 2. The semiconductor manufacturing apparatus according to claim 1, wherein the thermal emissivity of the shower head is monitored, and the thermal emissivity of the shower head is maintained at a constant value based on the monitoring result.