JPH08181112A - Method of cleaning dryetching device and manufacturing method of semiconductor device using the same - Google Patents

Abstract

PURPOSE: To provide the title dryetching device and manufacturing method of semiconductor device capable of cleaning a processing chamber and the whole space between a gas introducing valve and an exhaust valve for reducing gas as well as cutting down the maintenance cycle of the device. CONSTITUTION: The title dryetching device is arranged between a purge gas leading-in valve 9 and the exhaust valve 10 so as to periodically repeat the purging and vacuumizing steps. In such a composition, the pressure can be notably changed to relatively facilitate the convection of the atmosphere in a processing chamber 1 thereby enabling floating or adhering dust to be exhausted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a dry etching apparatus and a method for manufacturing a semiconductor device using the method.

[0002]

2. Description of the Related Art FIG. 6 shows a sectional view of a processing chamber 1 of a dry etching apparatus used in a conventional semiconductor device manufacturing method. In the conventional dry etching, the gas is introduced from the gas introduction port 5 by opening and closing the gas line valve 9,
A voltage is applied between the upper electrode plate 3 and the lower electrode plate 4 to cause discharge, and the CV on the substrate 2 placed on the lower electrode plate 4
The film formed by the D method or the like is etched. Further, the pressure inside the apparatus is adjusted by opening and closing the exhaust valve 10 to evacuate the exhaust line 6 with a turbo pump or a dry pump.

[0003]

When dry etching is carried out using a conventional dry etching apparatus, after the dry etching step, products of the etched film and reaction gas and products of resist and reaction gas are produced. Dust such as matter floated or adhered to the inside of the processing chamber 1, the gas inlet 5 and the exhaust line 6.

Therefore, it has been necessary to periodically open the atmosphere to perform mechanical cleaning. In addition, it is necessary to introduce a dedicated gas for cleaning while maintaining a vacuum after etching to perform plasma cleaning.
Only partial cleaning was performed between the upper electrode plate and the lower electrode plate in the discharge range, and dust was suspended or adhered to the other spaces.

The present invention has been made in order to solve the above-mentioned problems, and by making the pressure largely fluctuate, convection of the atmosphere in the processing chamber 1 is likely to occur, thereby floating or adhering. Since the dust is exhausted and the entire inside of the processing chamber 1 and between the gas introduction valve 9 and the exhaust valve 10 can be cleaned, the dust can be reduced and the cleaning cycle of the dry etching device can be shortened. The purpose is to get the law. A further object of the present invention is to provide a method of manufacturing a semiconductor device using the cleaning method.

[0006]

According to a first aspect of the present invention, there is provided a method of cleaning a dry etching apparatus for cleaning the inside of a processing chamber after dry etching, which comprises an intake line and an exhaust line communicating with the processing chamber. In between, cycle purge is performed by repeating purging and evacuation.

The invention according to claim 2 is characterized in that the cycle purge is periodically performed.

The invention according to claim 3 is the purging N ₂
Alternatively, a mass flow controller is installed in the O ₂ gas intake line to control the flow rate of the purge gas.

According to a fourth aspect of the present invention, a particle monitor for determining the timing of cycle purge and the timing of completion of purge is installed in the exhaust line to monitor the number of dust particles passing through the exhaust line. .

In the invention according to claim 5, the pressure range of the cycle purge is set within the range of 13.3 to 133 Pa.

According to a sixth aspect of the present invention, the upper limit of the pressure set value at the time of purging of the cycle purging is set to 1 Pa or more with respect to the capacity of the processing chamber of 100 liters.

According to the seventh aspect of the invention, the operation of evacuating the processing chamber and then rapidly introducing the purge gas into the processing chamber is repeated.

According to an eighth aspect of the present invention, there is provided a method of manufacturing a semiconductor device including a step of forming a desired pattern on the film by dry etching after the film is formed, and a cycle purge is performed by repeating purging and vacuuming after the dry etching. Is to do.

The invention according to claim 9 is characterized in that the cycle purge is periodically performed.

[0015]

In the operation of the invention according to claim 1, the entire processing chamber can be cleaned by the cycle purge, so that dust can be reduced and the maintenance cycle of the apparatus can be shortened. Therefore, the device yield can be increased.

With the operation of the invention according to claim 2, the dust can be further reduced by periodically performing the cycle purge.

According to the third aspect of the present invention, by installing a mass flow controller in the intake line of the N ₂ or O ₂ gas for purging, the flow rate of the purge gas can be accurately measured and the pressure can be set easily. Become.

The function of the invention according to claim 4 is to install a particle monitor for determining the timing of cycle purge and the timing of completion of purge in the exhaust line to thereby increase the timing of increase of particles requiring cycle purge. It is possible to determine the timing at which particles are reduced and completed by cycle purge.

In the operation of the invention according to claim 5, the cycle purge interval can be shortened by setting the cycle purge pressure range within the range of 13.3 to 133 Pa.

The operation of the invention according to claim 6 is that the upper limit of the pressure set value during the purging of the cycle purge is set to 1 Pa or more with respect to the capacity of the processing chamber of 100 liters, so that dust can be effectively collected in a short time. Can be reduced.

In the operation of the invention according to claim 7, after the vacuum is drawn, the purge gas is rapidly introduced into the processing chamber, whereby the function of separating the dust from the inner wall of the processing chamber and convection becomes stronger.

According to the eighth aspect of the invention, after the desired pattern is formed on the film by dry etching after the film is formed, the entire process chamber can be cleaned by the cycle purge, so that dust can be reduced and the maintenance of the apparatus can be performed. The cycle can be shortened. Therefore, the device yield can be increased.

With the operation of the invention according to claim 9, the dust can be further reduced by performing the cycle purge periodically.

[0024]

【Example】

[Embodiment 1] FIG. 1 is a graph showing the relationship between the purge gas flow rate and the degree of vacuum at the time of cycle purging in an embodiment of the cleaning method of the dry etching apparatus according to the present invention. is there.

The cleaning method of the dry etching apparatus of this embodiment is a cleaning method of the dry etching apparatus for cleaning the inside of the processing chamber after the dry etching, and it is performed regularly between the gas introduction valve and the exhaust valve. A feature is that cycle purging is performed by repeating purging and evacuation. By performing such cycle purging, the entire processing chamber can be regularly cleaned, so that dust can be further reduced. It should be noted that, instead of performing the cycle purge periodically, dust can be sufficiently reduced by performing the cycle purge irregularly at an appropriate time.

The change of the cycle purge with time is, for example, as shown in FIG.
By introducing at a flow rate of about / min, the degree of vacuum inside the processing chamber is set to 133 Pa, and the entire space including the processing chamber is cleaned. Vacuum level is 13.3P after 30 seconds
Change to a and set the degree of vacuum inside the processing chamber to 13.3 Pa.
Then, the purge gas is introduced again in the same manner as described above to adjust the degree of vacuum to 133 Pa. Hereinafter, this change is repeated.

The pressure range of the cycle purge is 1
Since it is set within the range of 3.3 Pa to 133 Pa, there is an effect of shortening the time of the cycle purge interval.

As shown in FIG. 2, which is an embodiment of the invention according to claim 6, the upper limit of the pressure setting value of the cycle purge is set to 1 Pa or more per 100 liters of the processing chamber capacity. , Can effectively reduce dust in a short time.

[Embodiment 2] Claims 1, 2 and 4 shown in FIG.
FIG. 3 is a cross-sectional view of a processing chamber of a dry etching apparatus to which an embodiment of the cleaning method of the dry etching apparatus according to the present invention is applied. Dry etching apparatus shown in FIG. 1, the processing chamber 1 for the dry etching of the substrate 2 made of a silicon wafer or glass, N ₂ for purging
Alternatively, an O ₂ gas intake line 5 and an O ₂ gas exhaust line 6 are communicated with each other, and an upper electrode plate 3 for discharge is provided inside the processing chamber 1.
And the lower electrode plates 4 are provided facing each other with a predetermined distance therebetween. Further, this dry etching apparatus is provided with a cycle purge mechanism for periodically repeating purging and evacuation at the timing shown in the graph of FIG.

The cycle purge mechanism is, for example, a CPU for controlling the opening and closing of the gas introduction valve 9 and the exhaust valve 10 and the gas introduction valve 9 and the exhaust valve 10.
12, and whether or not dust remains inside the processing chamber 1, the intake line 5 and the exhaust line 6,
It is composed of a particle monitor 11 installed in the exhaust line 6.

As the gas introduction valve 9 and the exhaust valve 10, for example, electromagnetic valves are used.

The particle monitor 11 is, for example,
The residual dust is monitored by measuring the cleanliness of the gas by measuring the number of particles with a size not less than the specified particle size in a certain volume using the scattering of laser light.

Since the apparatus of the second embodiment employs the above-described structure, the cycle purge mechanism is used to repeat the purging and evacuation as shown in FIG. By largely changing the pressure inside the gas discharge chamber 5 and the exhaust line 6, convection of the atmosphere in the processing chamber is likely to occur, whereby suspended or adhering dust is exhausted, and the inside of the processing chamber 1 and the gas introduction valve 9 are discharged. There is an effect that the space between the exhaust valves 10 can be cleaned.

Further, since the apparatus of the second embodiment is provided with the particle monitor 11 for determining the timing of the cycle purge and the timing of the completion of the purge in the exhaust line 6, the apparatus is used as in the first embodiment. If the dry etching apparatus is cleaned, it is possible to determine the timing at which the number of particles that require cycle purging increases and the timing at which particles are reduced and completed by cycle purging.

Further, the apparatus of the second embodiment has a purging N ₂
Alternatively, since the inlet port 5a of the O ₂ gas intake line and the inlet port 6a of the exhaust line 6 are installed on the two wall surfaces of the processing chamber 1 that face each other, the convection of the entire space including the processing chamber 1 is performed. Dust can be easily exhausted by eliminating the accumulation of dust.

Next, after dry etching the semiconductor substrate 2 using the apparatus of the second embodiment, the processing chamber 1,
A method of removing dust remaining inside the intake line 5 and the exhaust line 6 will be described. (1) First, the gas introduction valve 9 is closed, and the exhaust valve 10
And the inside of the processing chamber 1 is evacuated by the vacuum pump connected to the exhaust line 6. (2) Subsequently, the exhaust valve 10 is closed, the gas introduction valve 9 is opened, and the negative pressure inside the processing chamber 1 causes the N for purging.
₂ or O ₂ gas is introduced from the intake line 5. At this time, the dust remaining inside the processing chamber 1, the intake line 5, and the exhaust line 6 floats or peels off. (3) After reaching a certain pressure, the gas introduction valve 9 is closed and the exhaust valve 10 is opened. At this time, dust is discharged to the outside through the exhaust line 6. At this time, the driving of the vacuum pump is continued.

The above steps (1) to (3) are repeated until the particle monitor 11 determines that the air inside the processing chamber 1, the intake line 5 and the exhaust line 6 has reached the specified cleanliness. repeat.

During these series of procedures, the internal pressure of the processing chamber 1, the intake line 5 and the exhaust line 6 is changed by repeating the purging and evacuation as shown in FIG. 2 by using the cycle purging mechanism. It can vary greatly. This facilitates convection of the atmosphere in the processing chamber. Therefore, the dust that has floated or adhered is exhausted, and the inside of the processing chamber 1 and between the gas introduction valve 9 and the exhaust valve 10 can be cleaned.

[Embodiment 3] FIG. 4 is a sectional view of a processing chamber of a dry etching apparatus according to an embodiment of the present invention. Since the basic structure of this device is the same as that of the second embodiment, description of common parts is omitted. The structure of the dry etching apparatus of the present embodiment is characterized in that a mass flow controller 7 is installed in the intake line 5 for purging N ₂ or O ₂ gas as shown in FIG.

Since the apparatus of the third embodiment adopts the above-mentioned structure, if the dry etching apparatus is cleaned using the apparatus as in the first embodiment, the flow rate of the purge gas can be accurately measured. This makes it easy to set the pressure.

[Embodiment 4] An embodiment of the invention according to claim 7 will be described. When performing the cycle purge, instead of introducing the purge gas while maintaining the degree of vacuum constant as in the time-dependent change of the cycle purge of the first embodiment (see FIG. 1), as shown in FIG. After pulling, the operation of rapidly introducing the purge gas may be repeated. As shown in the graph of FIG. 5, the degree of vacuum decreases during purging, but the purge gas is rapidly introduced during a short period of time, so the dust adhering to the inside of the processing chamber is separated and convection is performed. The work to do becomes stronger.

[Embodiment 5] Next, a method of manufacturing a semiconductor device using the cleaning method of the dry etching apparatus of Embodiment 1 according to claims 8 and 9 will be described.

The method of manufacturing a semiconductor device of this embodiment can be applied to any method of manufacturing a semiconductor device such as a diode or a transistor as long as it includes a film forming step and a step of dry etching the film. It is a thing. Hereinafter, a method for manufacturing the semiconductor device of this embodiment will be described. Various films such as an insulating film or a semiconductor film are formed on a semiconductor substrate, and then a desired pattern is formed on the film by dry etching. After the dry etching is completed and the semiconductor substrate is carried out, the entire space including the processing chamber is continuously purged and evacuated repeatedly to perform cycle purging, whereby the entire processing chamber can be regularly cleaned. it can. After the dry etching process is completed, the semiconductor substrate is further subjected to conventionally known processes such as resist removal, impurity introduction, and electrode film formation to manufacture a semiconductor device.

It should be noted that dust can be sufficiently reduced by carrying out the cycle purge irregularly at an appropriate time instead of periodically carrying out the cycle purge.

[0045]

As described above, the effect of the invention according to claim 1 is that the dust in the processing chamber and the gas introduction port or the entire exhaust line can be reduced, and the maintenance cycle of the dry etching apparatus can be shortened. In addition, the device yield can be improved.

The effect of the invention according to claim 2 is that the dust can be further reduced by periodically performing the cycle purge.

The effect of the invention according to claim 3 is that the flow rate of the purge gas can be accurately measured by installing a mass flow controller in the intake line of the N ₂ or O ₂ gas for purging, and the pressure can be set easily. Become.

The effect of the invention according to claim 4 is to install a particle monitor for determining the timing of the cycle purge and the timing of the completion of the purge in the exhaust line to increase the timing of the increase in the number of particles requiring the cycle purge. It is possible to determine the timing at which particles are reduced and completed by cycle purge.

The effect of the invention according to claim 5 is that the cycle purge interval time can be shortened by setting the cycle purge pressure range within the range of 13.3 to 133 Pa.

The effect of the invention according to claim 6 is to effectively reduce the dust in a short time by setting the upper limit of the pressure setting value of the cycle purge to be at least 1 Pa or more for the capacity of the processing chamber of 100 liters. be able to.

The effect of the invention according to claim 7 is that the effect of separating dust from the inner wall of the processing chamber and convection becomes stronger, and the cleaning effect is high.

The effect of the invention according to claim 8 is that, after forming a desired pattern on the film by dry etching after film formation, the entire processing chamber can be cleaned by cycle purge, so that dust can be reduced and maintenance of the apparatus can be performed. The cycle can be shortened. Therefore, the device yield can be increased.

The effect of the invention according to claim 9 is that it is possible to further reduce dust by periodically performing cycle purge.

[Brief description of drawings]

FIG. 1 is a graph showing a time-series correspondence relationship between a purge gas flow rate and a degree of vacuum during cycle purging in an embodiment of a cleaning method for a dry etching apparatus according to the first, second and fifth aspects of the present invention.

FIG. 2 is a graph showing the change over time in the degree of vacuum during cycle purging in an example of the cleaning method of the dry etching apparatus of the invention according to claim 6;

FIG. 3 is a sectional view of a dry etching processing chamber to which an embodiment of the cleaning method of the dry etching apparatus according to the first, second and fourth aspects of the present invention is applied.

FIG. 4 is a sectional view of a dry etching apparatus to which an embodiment of a method for cleaning a dry etching apparatus according to the invention of claim 3 is applied.

FIG. 5 is a graph showing the change over time in the degree of vacuum during cycle purging in an example of the cleaning method of the dry etching apparatus of the invention according to claim 7;

FIG. 6 is a sectional view of a processing chamber of a conventional dry etching apparatus.

[Explanation of symbols]

1 processing chamber, 2 substrate, 3 upper electrode plate, 4 lower electrode plate, 5 intake line, 5a intake line inlet, 6 exhaust line, 6a exhaust line inlet, 7 mass flow controller, 8 dust, 9 gas inlet valve, 10
Exhaust valve, 11 particle monitor, 12 CPU for valve opening / closing control.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Saburo Osaki 997 Miyoshi, Nishigoshi-cho, Kikuchi-gun, Kumamoto Prefecture Advanced Display Co., Ltd.

Claims (9)

[Claims] 1. A method of cleaning a dry etching apparatus for cleaning the inside of a processing chamber after dry etching, comprising: cycle purging by repeating purging and vacuuming between an intake line and an exhaust line communicating with the processing chamber. A method for cleaning a dry etching apparatus, which comprises: 2. The cleaning method according to claim 1, wherein cycle purging is performed periodically. 3. The cleaning method according to claim 1, wherein a mass flow controller is installed in an intake line for purging N ₂ or O ₂ gas to control the flow rate of the purging gas. 4. The cleaning method according to claim 1, wherein a particle monitor for determining the timing of cycle purge and the timing of completion of purge is installed in the exhaust line to monitor the number of dust particles passing through the exhaust line. . 5. The cycle purge pressure range is 13.3 to
It is set within the range of 133 Pa.
The cleaning method described. 6. The upper limit of the pressure setting value at the time of purging of the cycle purge is 1 with respect to the volume of 100 liters in the processing chamber.
The cleaning method according to claim 1, wherein the cleaning method is Pa or more. 7. A vacuum is drawn in the processing chamber, and thereafter,
The cleaning method according to claim 1, wherein the operation of rapidly introducing the purge gas into the processing chamber is repeated. 8. A method for manufacturing a semiconductor device, which includes a step of forming a desired pattern on the film by dry etching after the film formation, wherein cycle purge is performed by repeating purging and vacuuming after the dry etching. Manufacturing method of semiconductor device. 9. The method according to claim 8, wherein the cycle purge is carried out periodically.