JPH09186092A - Manufacture of semiconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the atmospheric pressure difference in and out of a reaction chamber by rapidly opening the body of a relief valve against the elastic force of a spring when the interior of the chamber exceeds the atmosphere pressure, and communicating with the pressure reduction side including the chamber and the atmospheric side out of the chambers in cooperation with it. SOLUTION: A relief valve 14 for switching an opening 15 for communicating with the interior of a reaction chamber 1 and the exterior is provided at a base 6, a magnet switch(MS) 2 is provided between the upper surface of the collar 20 of its valve disc 16 and the lower surface of the base 6, the disc 16 closes the opening 15 of the base 6 to reduce the pressure in the chamber 1 to turn off during the processing of a wafer 5. The processing is finished, an inert gas is introduced so that the chamber 1 exceeds therein the atmospheric pressure, it is turned on, and when it coincides with the atmospheric pressure, the disc 16 of the valve 14 starts lowering, the MS 21 provided at the collar 20 is turned on, the base 6 is lowered, and a wafer 5 is taken out. The atmospheric pressure difference in and out of the chamber 1 is eliminated to obviate the engulfing or scattering of particles by air stream due to the atmospheric pressure difference and the adherence to the wafer 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor manufacturing apparatus, and more particularly to a semiconductor manufacturing apparatus that prevents particles from being generated or scattered due to a pressure difference inside and outside a reaction chamber when a wafer is taken out.

[0002]

2. Description of the Related Art In a semiconductor wafer processing step, a low pressure CVD apparatus, a vacuum vapor deposition apparatus, a sputtering apparatus or the like is used as a semiconductor manufacturing apparatus for forming a thin film on a wafer by reducing the pressure in a reaction chamber.

For example, in a low pressure CVD apparatus, the reaction chamber is evacuated by a vacuum pump to reduce the pressure, and then a reaction gas is introduced to form a desired thin film on the wafer surface by a chemical reaction under a predetermined heating condition. After the reaction treatment, the reaction gas is discharged and an inert gas is introduced into the reaction chamber to make the pressure inside the reaction chamber equal to the external pressure outside the reaction chamber. In this state, the wafer was taken out of the reaction chamber. In this case, the pressure inside the reaction chamber is detected by a pressure sensor provided in the pipe of the vacuum pump, and when the detected pressure becomes equal to the atmospheric pressure, the reaction chamber is opened to the outside air and the wafer is taken out.

[0004]

However, in the above-described conventional low pressure CVD apparatus, for example, the pressure when opening the reaction chamber to the outside air may not match the pressure of the outside air due to the sensitivity shift of the pressure sensor. . That is, in the sensor, the pressure in the reaction chamber is outside atmospheric pressure (for example, 760 Tor).
Although the detection signal is transmitted at r), the detection signal may actually be generated at a pressure equal to or lower than the atmospheric pressure such as 750 Torr or higher than the atmospheric pressure due to the sensitivity shift.

In such a case, the reaction chamber is opened to the outside air before the reaction chamber is brought to the outside pressure, or is opened when the outside pressure is slightly exceeded, so that the air flow is changed due to the pressure difference between the inside and the outside of the reaction chamber. Occurs. Due to this air flow, particles are caught in the reaction chamber from the outside or particles adhering to the inside of the reaction chamber are scattered, which adheres to the wafer and causes quality deterioration and poor characteristics, thus lowering the yield.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. When the reaction chamber is returned to the atmospheric pressure,
It is an object of the present invention to prevent particles from being scattered and attached to a wafer due to a difference in atmospheric pressure inside and outside a reaction chamber, and to provide a semiconductor manufacturing apparatus with high yield and high reliability.

[0007]

In order to achieve the above object, the present invention comprises a reaction chamber and a vacuum pipe for connecting the reaction chamber to a vacuum device, and after processing a wafer in the reaction chamber, In a semiconductor manufacturing apparatus in which an inert gas is introduced into the reaction chamber to return to the atmospheric pressure and the wafer is taken out, a valve main body for disconnecting the depressurized side including the reaction chamber and the outside air side outside the reaction chamber. And a seal member for the valve body, and when the reaction chamber matches the atmospheric pressure due to the introduction of the inert gas, the valve body opens and the pressure reducing side and the outside air side are opened. Provided is a semiconductor manufacturing apparatus, which is provided with a relief valve for communicating with each other.

In a preferred embodiment, the reaction chamber comprises a base driving device for mounting the wafer and a sensor for detecting an opening operation of the valve body of the relief valve, and the wafer is detected by a detection signal from the sensor. It is characterized in that it is configured to drive the mounted drive device.

In another preferred embodiment, the relief valve is provided on the base.

In still another preferred embodiment, the lily valve is provided in the vacuum pipe.

[0011]

[Function] When an inert gas is introduced into the reaction chamber to return it to the external pressure, if the pressure inside the reaction chamber exceeds the external pressure, the valve body of the relief valve quickly opens against the elastic force of the spring,
Since the pressure reduction side including the reaction chamber and the outside air side outside the reaction chamber communicate with each other, no pressure difference is generated inside and outside the reaction chamber.

Therefore, when the wafer is taken out by opening the reaction chamber to the outside air, an air flow due to a pressure difference is not generated, particles are prevented from being caught or scattered, and the particles are not attached to the wafer.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing the basic structure when a semiconductor manufacturing apparatus of the present invention is a low pressure CVD apparatus.

The reaction chamber 1 of the low pressure CVD apparatus accommodates a quartz inner core tube 4 supported by a lower support plate 3 in a quartz outer core tube 2 which is an outer casing, and the lower portion of the quartz outer core tube 2 is accommodated. This is a configuration in which a base 6 for moving the wafer 5 in and out is provided in the opening.

A large number of wafers 5 are supported in parallel in the grooves provided on the plurality of columns of the quartz boat 7 at appropriate intervals in the vertical direction. The quartz boat 7 is placed on the base 6 so that the quartz boat 7 can be accommodated in the quartz inner core tube 4.

A heater 8 for heating the inside of the quartz outer core tube 2 is provided on the outer periphery of the quartz outer core tube 2. Further, a vacuum pipe 9 connected to a vacuum pump (not shown) forming a part of a vacuum device is connected to the lower part of the quartz outer core tube 2 and above the support plate 3. An inlet 10 for an inert gas such as N2 gas is provided below the support plate 3. This inert gas is introduced in order to purge the reaction gas when the inside of the reaction chamber 1 is returned to the atmospheric pressure after the treatment, prevent the impure gas from being mixed from the outside, and keep the inside of the reaction chamber 1 clean.

A main valve 11 and a slow valve 12 in parallel with the main valve 11 are provided in the vacuum pipe 9. In this way, the two valves 11 and 12 are provided so that when the inside of the reaction chamber 1 is set to a high vacuum, only the slow valve 12 is first opened and gradually pulled to a certain vacuum, and then only the main valve is opened. This is to create a high vacuum.

The base 6 is connected to a known vertical lifting mechanism driven by a motor 13. This elevating mechanism is moved up and down by a motor 13 driven by a detection signal (ON signal) from a sensor which will be described later, opens the lower opening of the quartz outer core tube 2 and lowers the quartz boat 7 together with the base 6 to move the wafer. It is configured to move in and out.

In the present invention, the base 6 is further provided with a relief valve 14 for disconnecting the inside and outside of the reaction chamber 1. The relief valve 14 is configured to open when the pressure inside the reaction chamber 1 becomes equal to the external atmospheric pressure.

FIG. 2 shows the relief valve 14 according to the present invention.
It is explanatory drawing which shows the basic composition of. This relief valve 14
Is a valve body 16 that opens and closes an opening (hole) 15 that communicates the inside and outside of the reaction chamber 1 provided on the base 6, and supports the weight of the valve body 16 to act in a direction to close the opening 15. A spring 17, a seal member 18 that seals between the opening 15 and the valve body 16, and a support frame 1 that supports the seal member 18.
9 and 9.

The spring 17 has an elastic force corresponding to its own weight of the valve body 16, and therefore, when the pressure difference between the inside and the outside of the valve body is zero, no pressing force is applied to the valve body. The relief valve 14 is further provided with a magnet switch 21 between the upper surface of the collar portion 20 of the valve body 16 and the lower surface of the base 6. This magnet switch 21 is used for the valve body 1
When the valve 6 is closing the opening 15 of the base 6, that is, when the wafer 5 is being subjected to the reaction processing while the inside of the reaction chamber 1 is in a reduced pressure state, it is OFF and the valve body 16 opens the opening 15 of the base 6. When the wafer is opened, that is, the processing of the wafer 5 is completed, the reaction chamber 1
When the inside pressure exceeds the outside air pressure, this is detected and turned ON,
The detection signal is input to the motor 13.

According to the low-pressure CVD apparatus having the above-described structure, the reaction chamber 1 is evacuated by the vacuum pump connected to the vacuum pipe 9 to a high vacuum decompressed state, the reaction gas is introduced, and the reaction chamber 1 is supported by the quartz boat 7. The processed wafer 5 is processed. After the treatment, the reaction gas and the reaction product are discharged, an inert gas is introduced from the inlet 10, and the inside of the reaction chamber 1 is returned to the atmospheric pressure. When the inside of the reaction chamber 1 coincides with the atmospheric pressure, the pressing force of the spring 17 does not act and the valve body 16 of the relief valve 14 begins to fall due to its own weight. Therefore, the collar portion 20 of the valve body 16
The magnet switch 21 provided at is opened and turned on.
The state in which the pressure difference is zero detected by the magnet switch 21 is input to the motor 13 as an ON signal. When this ON signal is input, the motor 13 is driven, and the base 6 is lowered via a well-known transmission lifting mechanism.
The wafer 5 supported by the quartz boat 7 is taken out.

As described above, since the wafer 5 is taken out in a state where the inside of the reaction chamber 1 surely coincides with the outside air pressure, the pressure difference between the inside and the outside of the reaction chamber 1 does not occur, and the particles are entrained by the air flow due to the pressure difference. There is no possibility that the particles are attached to the wafer 5 by scattering or particles attached inside.

FIG. 3 is an explanatory diagram showing a modified example of the low pressure CVD apparatus of FIG. In this example, the relief valve 1
4 was provided in the vacuum pipe 9. Further, in this example, in addition to the relief valve 14, when an inert gas is introduced into the pressure reducing side including the reaction chamber 1 and the pressure reducing side significantly exceeds the external pressure (for example, 8
When the pressure exceeds 00 Torr), a protective pressure sensor 22 that detects this and outputs an ON signal is provided in the vacuum pipe 9. Further, a branch pipe 23 is provided in the vacuum pipe 9, and an opening / closing valve 24 that opens the branch pipe 23 by an ON signal of the protective pressure sensor 22.
And a check valve 25 to connect to a scrubber (not shown).

Even in such a structure, as in the embodiment of FIG. 1, the base 6 can be lowered by the action of the relief valve 14 with the pressure difference inside and outside the reaction chamber being completely zero. Further, according to the example of FIG. 3, even if the relief valve 14 does not operate and the depressurizing side including the reaction chamber 1 greatly exceeds the external atmospheric pressure due to the introduction of the inert gas,
This abnormal pressure state is detected by the protective pressure sensor 22,
The on-off valve 24 opens to allow the abnormal pressure to escape. This escaped gas is purified by the scrubber and reused.

In the above two embodiments, the low pressure CVD apparatus was used as the semiconductor manufacturing apparatus, but the present invention is not limited to this, and the wafer is processed by reducing the pressure inside the reaction chamber such as a vacuum vapor deposition apparatus and a sputtering apparatus. Any semiconductor manufacturing equipment may be used.

Further, in the above-mentioned two embodiments, the relief valve 14 is provided on the base 6 or the vacuum pipe 9, but the pressure reducing side and the outside air side such as other supporting portions of the quartz outer core tube 2 separate the wall. It may be provided at any place as long as it is opposite to the above.

Further, in the above two embodiments, the wafer 5 is loaded and unloaded through the lower opening of the reaction chamber 1. For example, a cap is provided on the upper portion of the reaction chamber 1, and the cap is opened and closed to load and unload the wafer 5. Good.

In the above two embodiments, the sensor is the magnet switch 21, but the sensor is not limited to this, and may be, for example, a photo coupler or a mechanical switch. Further, the raising / lowering mechanism of the base may be a cylinder drive or the like other than the motor.

[0030]

As described above, in the present invention, when the pressure inside the reaction chamber surely coincides with the outside air pressure and there is no pressure difference between the pressure reducing side including the reaction chamber and the outside air outside the reaction chamber, Since the wafer is taken out from the reaction chamber, there is a possibility that the wafer may be taken out of the reaction chamber when there is a pressure difference between the inside and outside of the reaction chamber due to the sensitivity difference of the sensor, and particles are entrained in the air flow due to the pressure difference. It is possible to prevent particles from adhering to the wafer by scattering particles adhering to the reaction chamber, improve the yield, and provide a highly reliable semiconductor manufacturing apparatus.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a basic configuration when a semiconductor manufacturing apparatus of the present invention is a low pressure CVD apparatus.

FIG. 2 is an explanatory diagram showing a basic configuration of a relief valve 14 according to the present invention.

FIG. 3 is an explanatory diagram showing a modified example of the apparatus of FIG.

[Explanation of symbols]

1: Reaction chamber, 2: Quartz outer core tube, 4: Quartz inner core tube, 5: Wafer, 6: Base, 7: Quartz boat, 13: Motor, 1
4: Relief valve, 15: Open, 16: Valve body, 17: Spring, 18: Seal member, 21: Magnet switch

Claims (4)

[Claims] 1. A reaction chamber and vacuum piping for connecting the reaction chamber to a vacuum device, wherein after processing a wafer in the reaction chamber, an inert gas is introduced into the reaction chamber to return to an external pressure. In the semiconductor manufacturing apparatus adapted to take out the wafer, a spring for supporting the valve body that closes the pressure-reducing side including the reaction chamber and the outside air side outside the reaction chamber so as to be closed, and a seal member for the valve body. And a relief valve configured to open the valve body when the reaction chamber matches the atmospheric pressure due to the introduction of the inert gas and to connect the depressurizing side and the external air side. Semiconductor manufacturing equipment. 2. The reaction chamber is provided with a drive device for a base on which the wafer is placed and a sensor for detecting an opening operation of a valve body of the relief valve, and a drive device for placing the wafer on the basis of a detection signal from the sensor. 2. The semiconductor manufacturing apparatus according to claim 1, wherein the base is driven to move the base. 3. The semiconductor manufacturing apparatus according to claim 2, wherein the relief valve is provided on the base. 4. The semiconductor manufacturing apparatus according to claim 2, wherein the lily valve is provided in the vacuum pipe.