JP2019099871A - Leak detection method of deposition film forming device and deposition film forming method - Google Patents

Abstract

To provide a simple and firm leak detection method of CVD device, and a deposition film forming method.SOLUTION: The deposition film forming method using a deposition film forming device 1 having a base, a reactor 2, an exhaust pipe 5 connected to the reactor through an exhaust bulb 13, includes; a step (1) for decompressing the reactor; a step (3) for arranging the base in the reactor; and a step (4) for forming a deposition film on the base by introducing raw material gas into the reactor and decomposing the raw material gas. Between (1) and (3), it includes a step (2) which measures a temperature T0 of a surface of the exhaust pipe with the exhaust pipe being closed, and a temperature T of the surface of the exhaust pipe after opening the exhaust bulb by flowing spontaneous combustion gas into the exhaust pipe, and which determines whether (temperature T- temperature T0) is a specified value or more. When (temperature T- temperature T0) is less than the specified value, it proceeds to the step (3), and when (temperature T- temperature T0) is the specified value or more, steps are performed again from the step (1) after a step for repairing the reactor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a leak detection method for a deposited film forming apparatus and a deposited film forming method.

It is regularly practiced to desorb the gate valve, reactor body or pump for maintenance of the CVD apparatus. However, if the assembly after maintenance is incomplete, a leak (gas leak) may occur on the way from the source gas supply device to the exhaust pipe through the reaction furnace, the pump and the exhaust branch pipe. Leaks have a significant impact on the properties of deposited films.
Conventionally, a leak detector using a probe gas such as helium has been used for leak detection in a CVD apparatus. Further, Patent Document 1 describes a method of measuring an oxygen partial pressure and a nitrogen partial pressure in a processing chamber with a leak detector (mass spectrometer) instead of helium and checking an external leak based on the ratio.

JP-A-8-45856

  As described above, conventionally, a leak detector using a probe gas such as helium has been used for leak detection in a CVD apparatus. However, the leak detector is expensive and causes an increase in manufacturing cost. Also, when using a leak detector, there are the steps of connecting the leak detector to the measurement port of the pump, blowing probe gas to all parts assembled after disassembling and testing, and removing leak detector. It will be necessary. As a result, the downtime of the device becomes long, which causes a drop in productivity.

  Also, since the leak detector can usually be used only at a pressure of about 1000 Pa or less, it is used by connecting to a measurement port provided near the pump inlet, ie, on the upstream side of the pump. Therefore, if there is a leak on the downstream side of the measurement port, that is, on the pump body and joints before and after the leak, the leak is detected by the reverse diffusion of the probe gas, so that there is a problem that the detection accuracy is lowered. Also, the measurement port usually uses a joint that is not very airtight, such as a clamp joint (quick coupling). As a result, the probe gas intrudes from the joint, sometimes making it difficult to distinguish the leak from the essential leak near the pump body.

  Therefore, an object of the present invention is to provide a method for reliably detecting a leak in a CVD apparatus by a simple method without using an expensive commercial leak detector. Another object of the present invention is to provide a method for forming a high quality deposited film in a state in which the leak is surely prevented.

According to one aspect of the present invention, in order to solve the above problems,
A deposited film forming method using a deposited film forming apparatus having a substrate, a reactor, and an exhaust pipe connected to the reactor via an exhaust valve,
Reducing the pressure in the reactor (1);
Placing the substrate in the reactor (3);
Introducing a source gas into the reactor and decomposing the source gas to form a deposited film on the substrate;
Between the steps (1) and (3)
Measuring the temperature T0 of the surface of the exhaust pipe with the exhaust valve closed;
After the pyrophoric gas flows into the exhaust pipe and the exhaust valve is opened, the temperature T of the surface of the exhaust pipe is measured,
It has a process (2) which judges whether (temperature T-temperature T0) is more than a regulation value,
If the (temperature T-temperature T0) is not equal to or higher than the specified value, the process proceeds to step (3),
In the case where the (temperature T-temperature T0) is equal to or higher than a specified value, a deposited film forming method for starting over from the step (1) is provided through the step of repairing the reaction furnace.

Also, according to another aspect of the present invention,
A leak detection method for a deposited film forming apparatus, comprising: a reaction furnace; and an exhaust pipe connected to the reaction furnace via an exhaust valve,
Depressurizing the reactor;
Measuring the temperature T0 of the surface of the exhaust pipe with the exhaust valve closed;
After the pyrophoric gas flows into the exhaust pipe and the exhaust valve is opened, the temperature T of the surface of the exhaust pipe is measured,
(Temperature T−temperature T0) has a step of determining whether it is a specified value or more,
Provided is a leak detection method for a deposited film forming apparatus, which determines that the deposited film forming apparatus leaks when the (temperature T−temperature T0) is equal to or higher than a specified value.

  According to the present invention, it is possible to provide a deposited film forming method and a leak detection method which can suppress the manufacturing cost because expensive equipment is not used for leak detection. Further, since the time for leak detection can be reduced as compared to the case of using a leak detector, it is possible to provide a deposited film forming method and a leak detection method capable of suppressing the downtime of the apparatus. In addition, it is possible to provide a deposited film forming method and a leak detection method capable of reliably detecting a leak around a pump which is difficult to detect by a conventional leak detector.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram explaining the deposited film formation apparatus which enforces the deposited film formation method of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram explaining the deposited film formation apparatus containing several CVD apparatus which implements the deposited film formation method of this invention. The flowchart explaining the deposited film formation method of this invention. The flowchart explaining the leak detection method of this invention.

Hereinafter, exemplary embodiments of the present invention will be exemplarily described in detail with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments.
In the present invention, when there is a leak in the CVD apparatus, the atmosphere is mixed into the exhaust pipe, and as a result, the reaction of the pyrophoric gas with oxygen causes the temperature of the surface of the exhaust pipe to rise.
[Description of deposited film forming apparatus]
FIG. 1 is a schematic view for explaining a deposited film forming apparatus for carrying out the deposited film forming method of the present invention. The deposited film forming apparatus has a CVD apparatus 1, an exhaust pipe 5, and an abatement apparatus 11.
The CVD apparatus 1 has a reaction furnace 2, a pump 3, an exhaust branch pipe 4, a gate valve 6, and a raw material gas supply device 7. The pump 3 is connected to the reactor 2 via the outlet valve 12 to decompress the reactor 2. The exhaust branch pipe 4 is connected to the pump 3. The gate valve 6 is provided at the top of the reaction furnace 2.

The exhaust branch pipe 4 is connected to the exhaust pipe 5 via the abatement exhaust valve 13. The inside of the exhaust pipe 5 is flowing nitrogen gas which is a purge gas supplied from the exhaust pipe gas supply device 8 and is maintained at a pressure slightly lower than the atmospheric pressure by a blower provided in the abatement device 11. A temperature sensor 9 is provided on the surface of the exhaust pipe 5 at a point where the exhaust branch pipe 4 joins the exhaust pipe 5 or on the downstream side of the point. The temperature sensor 9 measures the temperature of the exhaust pipe 5. The measured temperature of the exhaust pipe 5 is monitored by the film formation control device 10. As a means for measuring the temperature of the exhaust pipe 5, a noncontact radiation thermometer may be used in addition to a temperature sensor such as a thermocouple.
The exhaust branch pipe 4 is branched and connected to a scrubber device (not shown) via a scrubber exhaust valve 14. The scrubber device detoxifies gases that are not flammable gases.

The substrate is disposed inside the reaction furnace 2 through the gate valve 6. When the source gas is supplied from the source gas supply device 7 to the reaction furnace 2 and energy is applied to the source gas to decompose the source gas, a deposited film is formed on the substrate. The remaining source gas passes through the exhaust pipe 5 and is detoxified by the abatement device 11. As means for applying energy to the source gas, known means such as electric field, heat, light and the like are used.
FIG. 1 shows an example of a capacitively coupled high frequency CVD apparatus in which a high frequency power supply 15 is connected to the reaction furnace 2 via a matching box (not shown).
As shown in FIG. 2, a plurality of CVD apparatuses 1A, 1B, and 1C may be connected to the same exhaust pipe 5.

[Description of deposited film formation method]
As shown in FIG. 3, the deposited film forming method of the present invention is carried out as follows.
(Step 1)
First, the outlet valve 12 and the scrubber exhaust valve 14 are opened, and the inside of the reaction furnace 2 is depressurized by the pump 3 to a prescribed pressure. If the pressure does not reach the specified pressure, it is immediately detected that there is a leak. However, if the leak is very slight, the pressure may be reduced to a specified pressure. As described above, even if the pressure is reduced to a specified pressure because the leak is very small, the present invention can detect the leak in the following steps.

(Step 2)
The temperature T 0 of the exhaust pipe 5 before the abatement exhaust valve 13 is opened is measured by the temperature sensor 9.
The self-ignitable gas is supplied from the exhaust pipe gas supply device 8 to the exhaust pipe 5. Subsequently, the scrubber exhaust valve 14 is closed and the abatement exhaust valve 13 is opened.
A temperature sensor 9 measures the temperature T of the exhaust pipe 5 after a specified time has elapsed since the abatement exhaust valve 13 was opened.

If the CVD apparatus leaks, oxygen is mixed in the exhaust pipe 5. Then, the pyrophoric gas reacts with oxygen to generate heat.
When the value of (temperature T-temperature T0) is 1.0 ° C. or more, it is determined that the pyrophoric gas reacts with oxygen to generate heat, that is, the CVD apparatus has a leak. In this case, the outlet valve 12 and the abatement exhaust valve 13 are closed, and after repairing a portion which is considered to have a leak, the process is repeated from the step 1 again.
If the value of (temperature T−temperature T0) is less than 1.0 ° C., it is determined that heat generation has not occurred, that is, there is no leak in the CVD apparatus, and the process proceeds to the next step 3.

As the pyrophoric gas, silane (SiH ₄ ), diborane (B ₂ H ₆ ), arsine (AsH ₃ ), or phosphine (PH ₃ ) can be used. By using the same pyrophoric gas as the source gas, the increase in manufacturing cost can be suppressed.
In the configuration as shown in FIG. 2 in which a plurality of CVD devices are connected to the same exhaust pipe, the pyrophoric gas is supplied from the exhaust pipe gas supply device 8 instead of being supplied from the exhaust pipe gas supply device 8. It may be supplied from a raw material gas supply device of the CVD device.

  The supply amount of the pyrophoric gas is preferably in the range of 10 cc to 5000 cc. If it is 10 cc or more, an appropriate calorific value can be obtained and leak detection is easy. If the supply amount is large, the calorific value in the case of a leak will be large, but if the leak is very small, the amount of oxygen mixed in the exhaust pipe is small, so the amount of pyrophoric gas that can be combined with this is also limited. Therefore, 5,000 cc of the pyrophoric gas supply amount is sufficient.

  The length of the specified time is appropriately determined depending on the length of the exhaust pipe, the length of the exhaust branch pipe, and the flow rate of the pyrophoric gas in a range of 5 minutes to 1 hour. If there is fluctuation of room temperature during the specified time, it is judged by subtracting the influence of room temperature fluctuation from the value of temperature difference (temperature T-temperature T0).

(Step 3)
The substrate is disposed inside the reaction furnace 2 through the gate valve 6. When the reaction furnace 2 is opened to the atmosphere and the substrate is disposed, the pressure in the reaction furnace 2 is reduced and then the process proceeds to the next step 4. When the substrate is disposed while maintaining the reduced pressure without opening the reaction furnace 2 to the atmosphere, the process proceeds to the next step while maintaining the reduced pressure.

(Step 4)
The source gas is introduced into the reaction furnace 2 from the source gas supply device 7 and energy is applied to the source gas, whereby the source gas is decomposed to form a deposited film on the substrate.

[Description of leak detection method]
A leak detection method of the deposited film forming apparatus having a reaction furnace and an exhaust pipe connected to the reaction via an exhaust valve will be described based on FIG.
(Step 1)
Depressurize the reactor.
(Step 2)
While the exhaust valve is closed, the temperature T0 of the surface of the exhaust pipe is measured.
Next, a pyrophoric gas is supplied to the exhaust pipe and the exhaust valve is opened. After a predetermined time has elapsed, the temperature T of the surface of the exhaust pipe is measured.
And it is judged whether (temperature T-temperature T0) is more than a regulation value.
If (temperature T−temperature T0) is equal to or higher than a specified value, it is determined that the deposited film forming apparatus has a leak.
If (temperature T−temperature T0) is not equal to or higher than the specified value, it is determined that the deposited film forming apparatus has no leak.

Example 1
An amorphous silicon thin film containing nitrogen and carbon was formed by the CVD apparatus shown in FIG. After removing the abatement exhaust valve 13 and replacing the pump 3 as part of the regular maintenance, the deposited film forming method of the present invention was implemented.

The inside of the exhaust pipe 5 is supplied with nitrogen gas of 35 liters per minute from the exhaust pipe gas supply device 8 and is maintained at a pressure lower than the atmospheric pressure by 1 kPa by a blower provided in the harm removal device 11.
As step 1, first, the outlet valve 12 and the scrubber exhaust valve 14 were opened, and the inside of the reaction furnace 2 was depressurized by the pump 3 to a prescribed value of 0.13 Pa.
The temperature T0 of the exhaust pipe 5 was measured by the temperature sensor 9 in the process 2 and was 24.5 ° C.
Silane gas as a pyrophoric gas was supplied at 200 cc / min from the exhaust pipe gas supply device 8 to the exhaust pipe 5. Subsequently, the scrubber exhaust valve 14 was closed and the abatement exhaust valve 13 was opened. The temperature T of the exhaust pipe 5 measured 10 minutes after the abatement exhaust valve 13 was opened was 35.0 ° C. when measured by the temperature sensor 9.
(Temperature T-temperature T0) was 10.5 ° C., which was 1 ° C. or more of the specified value. It was determined that there was a leak.

Therefore, the outlet valve 12 and the abatement exhaust valve 13 were closed, and an air vent was made between them to correct the attachment of the pump 3. Thereafter, the outlet valve 12 and the scrubber exhaust valve 14 were opened again as step 1, and the step of reducing the pressure in the reaction furnace 2 to a specified value of 0.13 Pa by the pump 3 was performed.
The temperature T0 of the surface of the exhaust pipe 5 was measured by the temperature sensor 9 in Step 2 and found to be 24.5 ° C.
Silane gas as a pyrophoric gas was supplied at 200 cc / min from the exhaust pipe gas supply device 8 to the exhaust pipe 5. Subsequently, the scrubber exhaust valve 14 was closed and the abatement exhaust valve 13 was opened. The temperature T of the surface of the exhaust pipe 5 measured 10 minutes after opening the abatement exhaust valve 13 was 24.5 ° C. as measured by the temperature sensor 9.
(Temperature T-temperature T0) was 0 ° C., which was less than the prescribed value of 1 ° C., so it was judged that there was no leak.

In step 3, a vacuum transfer device for transferring the substrate was connected to the top of the reaction furnace 2, the gate valve 6 was opened, the substrate was placed from the vacuum transfer device inside the reaction chamber 2, and the gate valve 6 was closed.
In step 4, the source gas was supplied from the source gas supply device 7 to the reaction furnace 2. As source gases, 390 cc of silane, 780 cc of hydrogen, 300 cc of methane and 24 cc of nitrogen monoxide were supplied, respectively, and the rotation speed of the pump 3 was adjusted so that the internal pressure was 0.3 Torr. The source gas was decomposed by applying high frequency power of 13.56 MHz and 400 W from the high frequency power source 15 to the reaction furnace 2 to be plasma to form a deposited film on the substrate.

Example 2
In the deposited film forming apparatus shown in FIG. 2, a plurality of CVD apparatuses 1A, 1B, and 1C are connected to a common exhaust pipe 5 via the abatement exhaust valves 13A, 13B, and 13C. As part of the regular maintenance, after removing the abatement exhaust valve 13B of the CVD apparatus 1B and replacing the pump 3B, the deposited film forming method of the present invention was performed by the CVD apparatus 1B.

The inside of the exhaust pipe 5 is supplied with nitrogen gas of 35 liters per minute from the exhaust pipe gas supply device 8 and is maintained at a pressure lower than the atmospheric pressure by 1 kPa by a blower provided in the abatement device 11.
In step 1, first, the outlet valve 12B and the scrubber exhaust valve 14B were opened, and the inside of the reaction furnace 2B was decompressed to a specified value of 0.13 Pa by the pump 3B.
The temperature T0 of the surface of the exhaust pipe 5 was measured by the temperature sensor 9B in step 2 and was 24.5 ° C.
The source gas supply unit 7A of the CVD apparatus 1A uses the silane gas as a part of the source gas to form a deposited film of amorphous silicon, and the residual gas of 1600 cc / min of silane gas supplied to the CVD apparatus 1A is natural It was supplied to the exhaust pipe 5 as an ignitable gas.

Subsequently, the scrubber exhaust valve 14B was closed and the abatement exhaust valve 13B was opened. The temperature T of the surface of the exhaust pipe 5 measured 10 minutes after opening the abatement exhaust valve 13B was 39.0 ° C. as measured by the temperature sensor 9B.
Since T-T0 was 14.5 ° C. and 1 ° C. or more of the specified value, it was judged that there was a leak.

Therefore, the outlet valve 12B and the abatement exhaust valve 13B were closed, and the air was vented between them to correct the attachment of the pump 3B. Thereafter, again in step 1, the outlet valve 12B and the scrubber exhaust valve 14B were opened, and the step of reducing the pressure in the reaction furnace 2B to a prescribed value of 0.13 Pa by the pump 3B was performed.
In step 2, the temperature T0 of the exhaust pipe 5 was measured by the temperature sensor 9B and found to be 24.5.degree.
Subsequently, the scrubber exhaust valve 14B was closed and the abatement exhaust valve 13B was opened. The temperature T of the surface of the exhaust pipe 5B 10 minutes after the abatement exhaust valve 13B was opened was measured by the temperature sensor 9B and found to be 24.5.degree. (Temperature T-temperature T0) was 0 ° C., which was less than the prescribed value of 1 ° C., so it was judged that there was no leak.

  Thereafter, a deposition film was formed by the CVD apparatus 1B in the same manner as in step 3 and subsequent steps of the first embodiment. In the deposited film forming apparatus in which a plurality of CVD apparatuses are connected to the common exhaust pipe 5 as in the present embodiment, the pyrophoric gas may be supplied from a CVD apparatus other than the CVD apparatus which performs a leak inspection. is there. In such a case, it is not necessary to provide a gas line for supplying the pyrophoric gas to the exhaust pipe 5 in the exhaust pipe gas supply device, and the cost of the device can be suppressed.

DESCRIPTION OF SYMBOLS 1 CVD apparatus 2 reaction furnace 3 pump 4 exhaust branch pipe 5 exhaust piping 6 gate valve 7 raw material gas supply apparatus 8 exhaust piping gas supply apparatus 9 temperature sensor 10 film formation control apparatus 11 abatement apparatus 12 outlet valve 13 abatement exhaust valve 14 scrubber Exhaust valve

Claims (6)

A deposited film forming method using a deposited film forming apparatus having a substrate, a reactor, and an exhaust pipe connected to the reactor via an exhaust valve,
Reducing the pressure in the reactor (1);
Placing the substrate in the reactor (3);
Introducing a source gas into the reactor and decomposing the source gas to form a deposited film on the substrate;
Between the steps (1) and (3)
Measuring the temperature T0 of the surface of the exhaust pipe with the exhaust valve closed;
After the pyrophoric gas flows into the exhaust pipe and the exhaust valve is opened, the temperature T of the surface of the exhaust pipe is measured,
It has a process (2) which judges whether (temperature T-temperature T0) is more than a regulation value,
If the (temperature T-temperature T0) is not equal to or higher than the specified value, the process proceeds to step (3),
A method for forming a deposited film, comprising reworking from the step (1) through a step of repairing the reaction furnace when the (temperature T-temperature T0) is equal to or higher than a specified value.   The deposited film forming method according to claim 1, wherein the pyrophoric gas is a raw material gas of another reaction furnace connected to the exhaust pipe.   The deposited film forming method according to claim 1 or 2, wherein the pyrophoric gas is silane, diborane, arsine or phosphine. A leak detection method for a deposited film forming apparatus, comprising: a reaction furnace; and an exhaust pipe connected to the reaction furnace via an exhaust valve,
Depressurizing the reactor;
Measuring the temperature T0 of the surface of the exhaust pipe with the exhaust valve closed;
After the pyrophoric gas flows into the exhaust pipe and the exhaust valve is opened, the temperature T of the surface of the exhaust pipe is measured,
(Temperature T−temperature T0) has a step of determining whether it is a specified value or more,
When the (temperature T-temperature T0) is equal to or higher than a specified value, it is determined that the deposited film forming apparatus has a leak, and the leak detection method of the deposited film forming apparatus is characterized.   The leak detection method of the deposited film forming apparatus according to claim 4, wherein the pyrophoric gas is a raw material gas of another reaction furnace connected to the exhaust pipe.   The leak detection method for a deposited film forming apparatus according to claim 4 or 5, wherein the pyrophoric gas is silane, diborane, arsine or phosphine.

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