TWI689802B - Gas supply control method - Google Patents

Abstract

Quickly supply the desired flow of gas into the chamber.

To provide a gas supply control method that uses a pressure-controlled flowmeter, a first valve measured upstream and a second valve measured downstream, where the pressure-controlled flowmeter has a connection to the first The control valves of 1 and 2 valves, and the orifice provided between the control valve and the 2nd valve, the volume V ₁ of the gas supply pipe between the orifice and the control valve, and the orifice and the 2nd valve the gas supply pipe between the volume V ₂ to V ₁ / V ₂ ≧ 9, the pressure P of the gas supply pipe between the orifice and the control valve between the gas supply pipe ₁ and the second valve aperture and the second pressure P ₂ During the gas supply period, P ₁ >2×P ₂ is maintained, the first valve is opened, and the supply of gas is controlled by the opening and closing control of the second valve in a state where the control valve is controlled.

Description

Gas supply control method

The invention relates to a gas supply method.

In the semiconductor manufacturing apparatus, the substrate is subjected to fine processing by the action of the gas supplied into the chamber. At this time, a device used for gas flow control, for example, a pressure type flow control device shown in Patent Document 1 is proposed. The pressure-type flow control device is connected to the gas supply pipe for supplying gas from the gas supply source into the chamber, and controls the opening and closing degree of the control valve to control the flow rate of the gas flowing through the gas supply pipe.

【Prior Technical Literature】

【Patent Literature】

Patent Document 1: Japanese Patent Laid-Open No. 2004-5308

However, in the control of the control valve disclosed in Patent Document 1, it takes time until the desired flow rate of gas is supplied into the chamber, which becomes a factor that deteriorates the semiconductor manufacturing yield. In addition, during the supply of the desired flow rate of gas, since the gas whose flow rate is not controlled is supplied into the chamber, it is impossible to perform fine processing of the substrate well, which becomes a factor that affects the characteristics of the semiconductor.

In view of the above-mentioned problems, in one aspect of the present invention, the object is to quickly supply a desired flow of gas into the chamber.

In order to solve the above-mentioned problems, the same state provides a gas supply control method, which uses a pressure control type flow meter provided in the gas supply line, a first valve provided on the gas supply line upstream of the pressure control type flow meter, A gas supply control method of a second valve provided on the gas supply line downstream of the pressure-controlled flowmeter, the pressure-controlled flowmeter has a control valve connected to the first valve and the second valve, and An orifice between the control valve and the second valve; the volume V ₁ of the gas supply pipe between the orifice and the control valve and the gas supply pipe between the orifice and the second valve The volume V ₂ is the relationship of V ₁ /V ₂ ≧9; the pressure P ₁ of the gas supply pipe between the orifice and the control valve and the pressure P of the gas supply pipe between the orifice and the second valve ₂ Maintain P ₁ >2×P ₂ during gas supply; open the first valve, and control the supply of gas by the opening and closing control of the second valve with the control valve controlled.

Depending on the phase, the desired flow of gas can be quickly supplied into the chamber.

1‧‧‧ gas supply control system

10‧‧‧Semiconductor manufacturing equipment

11‧‧‧Gas shower head (upper electrode)

12‧‧‧Mounting table (lower electrode)

13‧‧‧High frequency power supply

15‧‧‧ gas supply line

15a, 15b‧‧‧gas supply pipe

20‧‧‧Pressure flow control device

21‧‧‧Control valve

22‧‧‧Control circuit

23‧‧‧ Orifice

24, 25‧‧‧ pressure gauge

30‧‧‧Gas supply source

VL1‧‧‧First valve

2 valves for VL2‧‧‧

C‧‧‧Chamber

FIG. 1 is a diagram showing an example of the overall configuration of a gas supply control system according to an embodiment.

FIG. 2 is a diagram showing an example of a gas supply control method and gas flow rate related to a comparative example.

FIG. 3 is a diagram showing an example of a gas control method and gas flow rate related to an embodiment.

4 is a diagram showing an example of an embodiment and a comparative example due to the luminous intensity of gas.

FIG. 5 is a diagram showing an example of the pressure in the volume ratio of the gas supply pipe around the orifice related to the comparative example.

6 is a diagram showing an example of the pressure in the volume ratio of the gas supply pipe around the orifice according to an embodiment.

FIG. 7 is a diagram showing an example of the change of the gas supply pipe volume ratio and the equilibrium pressure around the orifice according to an embodiment.

FIG. 8 is a diagram showing an example of the relationship between the predetermined time T and the etching rate according to an embodiment.

9 is a diagram showing an appropriate range of the gas supply pipe volume ratio around the orifice according to an embodiment.

FIG. 10 is a flowchart showing an example of a rapid interaction procedure using the gas supply control method of an embodiment.

Fig. 11 is a diagram for explaining a gas supply control method according to a modification of the embodiment.

FIG. 12 is a diagram showing an example of the overall configuration of a gas supply control method related to a modification of the embodiment.

FIG. 13 is a flowchart showing an example of a rapid interaction procedure using the gas supply control method according to a modification of the embodiment.

FIG. 14 is a flowchart showing an example of a rapid interaction procedure using the gas supply control method according to a modification of the embodiment.

In the following, the mode for carrying out the present invention will be described with reference to the drawings. In addition, in this specification and the drawings, the substantially same configuration is given the same symbol to omit redundant description.

[Overall Configuration of Gas Supply Control System]

First, an example of the overall configuration of the gas supply control system 1 according to an embodiment of the present invention will be described with reference to FIG. 1. The gas supply control system 1 is a system that controls the gas supplied to the semiconductor manufacturing apparatus 10.

(Configuration example of semiconductor manufacturing equipment)

The semiconductor manufacturing apparatus 10 has a cylindrical chamber C made of aluminum whose surface is subjected to alumite treatment (anodizing treatment). Chamber C is grounded. A mounting table 12 is provided inside the chamber C. The wafer W is placed on the mounting table 12.

The mounting table 12 is connected to a high-frequency power source 13 for exciting plasma through a matching device 13a. For example, the high-frequency power supply 13 applies a high-frequency power suitable for generating plasma in the chamber C, such as 60 MHz, to the mounting table 12. In this way, the mounting table 12 will mount the wafer W and function as a lower electrode. The matching device 13a integrates the load impedance into the internal (or output) impedance of the high-frequency power supply 13. When the matching device 13a generates plasma in the chamber C, it functions so that the internal impedance of the high-frequency power source 13 and the load impedance appear to match.

A gas shower head 11 as an upper electrode is provided on the top of the chamber C. In this way, the high-frequency power from the high-frequency power source 13 is capacitively applied between the mounting table 12 and the gas shower head 11. The gas is introduced from the gas inlet 14 of the gas shower head 11 and is supplied into the chamber C through the gas buffer space 11b from the plurality of vent holes 11a.

The semiconductor manufacturing apparatus 10 performs microfabrication on the wafer W by the action of a desired gas applied to the chamber C. At this time, the gas flow control system uses the pressure type flow control device 20.

(Configuration example of pressure type flow control device)

The pressure-type flow control device 20 is connected to a gas supply line 15 for supplying gas from the gas supply source 30 to the semiconductor manufacturing device 10. The pressure type flow control device 20 controls the opening and closing degree of the control valve 21 to control the flow rate of gas flowing into the chamber C through the gas supply line 15. An example of the control valve 21 is a metal diaphragm valve driven by a solenoid valve. The pressure type flow control device 20 has a control valve 21, an opening and closing degree control circuit 22 of the control control valve 21, an orifice Port 23, pressure gauges 24, 25, gas supply pipe 15a and gas supply pipe 15b. The orifice 23 is provided between the gas supply pipe 15a and the gas supply pipe 15b. The gas supply pipe 15a is a gas pipe from the orifice 23 to the control valve 21. The gas supply pipe 15b is a gas pipe from the orifice 23 to the second valve VL2. The gas supply pipe 15 a and the gas supply pipe 15 b are connected to the gas supply line 15. The pressure-type flow control device 20 is an example of a pressure-controlled flow meter installed in a gas supply line.

The pressure in the gas supply pipe 15a is P ₁ and the volume is V ₁ . The pressure in the gas supply pipe 15b is P ₂ and the volume is V ₂ . When the pressures P ₁ and P ₂ of the gas supply pipe 15 a and the gas supply pipe 15 b inside the pressure type flow control device 20 are controlled so as to slightly satisfy the critical expansion pressure condition P ₁ >2×P ₂ , they flow through the orifice The gas flow rate Q of 23 is determined only by the pressure P1 on the upstream side of the orifice 23, and is expressed by the following relationship (1).

Q=CP ₁ …(1)

The pressure type flow control device 20 uses the above formula (1) to adjust the pressure P ₁ by the control valve 21 so that the gas flow rate Q on the downstream side of the orifice 23 is controlled at a desired value consistent with the program conditions. In addition, C in the above formula (1) is a constant determined by the diameter of the orifice 23 and the gas temperature. The pressure P ₁ and the pressure P ₂ are measured by the pressure gauge 24 and the pressure gauge 25, respectively.

A first valve VL1 is arranged on the upstream side (gas supply source side) of the pressure type flow control device 20, and a second valve VL2 is arranged on the downstream side (semiconductor manufacturing device side) of the pressure type flow control device 20. The first valve VL1 and the second valve VL2 can be controlled to be fully open or fully closed.

When the semiconductor manufacturing apparatus 10 of the related structure performs processes such as etching, first, the wafer W is carried into the chamber C and placed on the mounting table 12. The pressure in the chamber C will be reduced to a vacuum state. The gas output from the gas supply source 30 is spray-introduced into the chamber C from the gas shower head 11. The predetermined high-frequency power output by the high-frequency power source 13 is applied to the mounting table 12.

The introduced gas is ionized and dissociated by the plasma generated by the high-frequency power to plasma-etch the wafer W. After processing such as plasma etching, the wafer W is carried out of the chamber C. In addition, the semiconductor manufacturing apparatus 10 is not necessarily limited to the case where plasma is used for processing, and the wafer W may be subjected to fine processing by heat treatment or the like.

[Gas supply control method]

Next, the gas supply control method related to the comparative example will be described with reference to FIG. 2, and then the gas supply control method related to this embodiment will be described with reference to FIG. 3. Comparative examples The related gas supply control method controls the gas supply by the opening and closing control of each valve shown in (a) of FIG. 2.

2(a) shows time on the horizontal axis, and the vertical axis shows the control states of the first valve VL1, the second valve VL2, and the control valve 21, respectively. Fig. 2(b) shows the time on the horizontal axis and the pressures P ₁ and P _{2 of the} pressure type flow control device (FCS) on the vertical axis. FIG. 2(c) shows the time on the horizontal axis and the gas flow rate through the second valve VL2 on the vertical axis.

Each valve is controlled in the order of step 1→step 2→step 3→step 2→step 3... Steps 2 and 3 will be repeated a predetermined number of times.

In addition, the first valve VL1 and the second valve VL2 can be controlled to be fully open or fully closed. The control valve 21 can be adjusted from fully open to fully closed. When the first valve and the second valve are "OPEN", it indicates that the valve is fully open. In addition, when the first valve and the second valve are "CLOSE", it indicates that the valve is fully closed. When the control valve 21 is "in control", the opening and closing degree of the control valve 21 is controlled by the control of the control circuit 22, and gas at a flow rate corresponding to the opening and closing degree is supplied. When the control valve 21 is in "control stop", the control valve 21 is fully closed and gas supply is stopped.

The status of each valve in each step is shown below.

(step 1)

In step 1, the first valve VL1 and the second valve VL2 are controlled to be fully closed, the control of the control valve 21 is stopped, and the gas supply is stopped.

(Step 2)

In step 2, the first valve VL1 and the second valve VL2 are controlled to be fully opened, and then the control valve 21 becomes under control, and the gas supply is started.

The sequence of opening and closing operations of the first valve VL1 and the second valve VL2 may be simultaneous, or the opening operation of the first valve VL1 may be performed after a predetermined time elapses after the second valve VL2 performs the opening operation. After the opening operations of the first valve VL1 and the second valve VL2 are completed, the control valve 21 is controlled. Therefore, after the opening operations of the first valve VL1 and the second valve VL2 are completed, the control operation of the control valve 21 will start after a predetermined time T has elapsed. In the embodiment, the predetermined time is 200 msec, but it is not limited thereto.

(Step 3)

In step 3, the first valve VL1 and the second valve VL2 are controlled to be fully closed, and then the control of the control valve 21 is stopped again, and the gas supply is stopped.

For the control of the valves in the above steps, the pressures P ₁ and P ₂ of the pressure type flow control device 20 (FCS) shown in FIG. 2(b) and the flow of the second valve VL2 in FIG. 2(c) To illustrate the gas flow rate.

Before the gas is stopped, the critical expansion pressure condition P ₁ >2×P ₂ is satisfied. Therefore, in step 1, after the gas supply is stopped, the gas supply pipe 15a and the gas supply pipe 15b may cause gas Because of the movement, the pressure P ₁ shown in (b) of FIG. 2 gradually decreases, and the pressure P ₂ gradually increases. Also, as shown in (c) of FIG. 2, no gas flows in the second valve VL2.

In step 2, first, the first valve VL1 and the second valve VL2 are controlled to be fully opened. As a result, as shown in FIG. 2(b), the pressures P ₁ and P ₂ will temporarily decrease, and as shown in FIG. 2( c), the second valve VL2 will flow the residual gas to the gas supply pipe 15a and the gas supply. After the tube 15b, it is lowered. Then, as shown in FIG. 2(a), since the control valve 21 in the pressure type flow control device 20 will start to control, the pressure P ₁ shown in FIG. 2(b) will rise, and the second valve VL2 will Circulation has a predetermined flow.

After that, when the control valve 21 becomes under control, as shown in FIG. 2(b), the pressures P ₁ and P _{2 of the} gas supply pipe 15a and the gas supply pipe 15b are controlled to be fixed, as shown in FIG. 2(c) As shown, the gas flow rate through the second valve VL2 is controlled to be fixed. That is, when the control valve 21 is under control, the flow rate of the gas supplied to the chamber C is controlled to a predetermined amount.

In step 3, after the first valve VL1 and the second valve VL2 are controlled to be fully opened, the control valve is brought into a fully closed state to stop the gas supply. As a result, the gas supply pipe 15a and the gas supply pipe 15b are about to be in an equilibrium state, causing gas to move. As a result of this, as shown in FIG. 2(b), the pressure P _{1 of} the gas supply pipe 15a decreases and the pressure P _{2 of the} gas supply pipe 15b increases. In step 3, as shown in (c) of FIG. 2, no gas flows through the second valve VL2.

FIG. 4 shows the temporal change of the flow rate of the gas supplied into the chamber C by the luminous intensity in the chamber C. FIG. When the luminous intensity in chamber C becomes higher, it shows that the gas flow rate increases. In addition, when the luminous intensity in the chamber C becomes low, it shows that the gas flow rate is reduced.

In the comparative example, as shown in step 2 of (a) of FIG. 2, (1) the first valve VL1 and the second valve VL2 will be fully opened, and (2) after that, the control valve 21 will be under control. In the comparative example, the gas supply is started when the second valve VL2 is opened. Therefore, after the opening operation of the first valve VL1 and the second valve VL2 until the control valve 21 becomes a predetermined time T under control, the gas supply pipe between the first valve VL1 and the second valve VL2 shown in (a) of FIG. 2 The gas G remaining inside flows through the second valve VL2 and is supplied to the chamber C. When the control valve 21 starts control, the gas controlled to a predetermined flow rate flows through the second valve VL2 and is supplied to the chamber C. As a result, in the comparative example, in step 2 In the two-stage control of (1) and (2), the flow rate of the gas supplied into the chamber C is controlled at a predetermined flow rate after the generation of the two stages I1, I2 in FIG. 4 starts.

As shown in FIG. 4, the height and tendency of the start of the gas flow in the first stage I1 before starting the control of the control valve 21 are determined by the residual gas in the pressure type flow control device 20. The state of this residual gas will vary depending on the use state of the pressure type flow control device 20 before the start of the gas supply or the individual difference of the pressure type flow control device 20. Therefore, it is difficult to completely manage the start of the gas flow of the first stage I1. Therefore, in particular, the emission intensity waveform of the first stage I1, that is, to completely manage the gas flow control of the first stage I1 is more difficult than the gas flow control of the second stage I2.

To eliminate one of the methods for starting the first stage I1 of the gas flow rate, there is a method of making the fluctuation of the pressure P ₁ small while the gas supply is stopped. One of the means to realize this method is the gas supply control method related to this embodiment.

In the gas supply control method according to this embodiment, the valve used for gas flow control is one of the second valves VL2. As a result, it is possible to suppress a sudden change in the gas flow rate supplied into the chamber C when the gas supply in the chamber C starts from the two stages I1 and I2.

Specifically, the gas supply control method according to this embodiment controls each valve as shown in (a) of FIG. 3. The status of each valve in each step is shown below.

(step 1)

In step 1, the first valve VL1 is controlled to be fully open, and the control valve 21 is under control. The second valve VL2 is controlled to be completely closed, and the gas supply is stopped.

(Step 2)

In step 2, the first valve VL1 is controlled to be fully open, and the control valve 21 is maintained under control. The second valve VL2 is controlled to be fully opened and the gas supply is started.

(Step 3)

In step 3, the first valve VL1 is controlled to be fully open, and the control valve 21 is maintained under control. The second valve VL2 is controlled to be completely closed, and the gas supply is stopped.

For the control of the valves in each step, the pressures P ₁ and P ₂ of the pressure type flow control device 20 (FCS) shown in FIG. 3(b) and the second valve VL2 in FIG. 3(c) are circulated To illustrate the gas flow rate. In this embodiment, in all steps, the first valve VL1 is controlled to be opened, and the control valve 21 is maintained under control. Therefore, the pressure P _{1 of the} gas supply pipe 15a is fixed.

In this embodiment, the pressure P _{2 of the} gas supply pipe 15b and the gas flow rate through which the second valve VL2 flows vary depending on the opening and closing of the second valve VL2. That is, in step 1 of the present embodiment shown in FIG. 3(a), since the second valve VL2 is in the open state, as shown in FIG. 3(b), the pressure P _{2 of the} gas supply pipe 15b becomes high When the same pressure as the pressure P ₁ is reached, it is maintained at this pressure. In addition, as shown in (c) of FIG. 3, no gas flows through the second valve VL2. In step 2, the second valve VL2 will be opened. Corresponding to this, as shown in (b) of FIG. 3, the pressure P ₂ will be lowered and maintained at the predetermined pressure. In addition, as shown in FIG. 3(c), the second valve VL2 flows a predetermined flow of gas. In step 3, the second valve VL2 is closed again. As shown in (b) of FIG. 3, the pressure P _{2 of the} gas supply pipe 15b becomes higher, and when the same pressure as the pressure P ₁ is reached, it is maintained at this pressure. As shown in (c) of FIG. 3, no gas flows through the second valve VL2.

As a result, in the present embodiment, the flow rate of the gas flowing through the second valve VL2 is fixed according to the opening and closing of the second valve VL2, and the gas after the controlled flow rate is supplied to the chamber C. This may be because the first valve VL1 is frequently opened, and the control valve 21 is often being controlled, so there is no uncontrollable gas remaining in the pressure-type flow control device 20, but can be changed with the second valve VL2. Open and close to control the gas flow.

As described above, the body supply control method according to this embodiment always opens the first valve VL1, and always controls the control valve 21 under control. As a result, when the second valve VL2 is opened to start the gas supply, a part of the gas existing on the downstream side of the orifice 23 with resistance does not pass through the orifice 23 and can be smoothly supplied into the chamber C. As a result, the gas is supplied into the chamber C shortly after the gas supply is started, and as a result, the two-stage start of the gas flow rate as shown in the comparative example of FIG. 4 can be eliminated.

However, the gas supply control method, the pressure P ₁ is P and the pressure fluctuation does not trigger _2, so that the flow rate control is repeated (ON → OFF → ON ...) in a very short period, and since the pressure P ₁ is The pressure P ₂ does not reach equilibrium, so it is difficult to avoid the start of the second phase.

Therefore, in the present embodiment, the ratio V ₁ /V ₂ of the volumes V ₁ and V ₂ in the gas supply pipe 15 a and the gas supply pipe 15 b of the pressure type flow control device 20 using the above gas supply control method is optimized . In this way, by using the pressure-type flow control device 20 in which the ratio V ₁ /V _{2 of the} volumes V ₁ and V ₂ is optimized to implement the gas supply control method of this embodiment, it is possible to completely avoid the residual gas The 2nd stage of gas flow begins. Next, the optimization of the volume ratio V ₁ /V _{2 in} the gas supply pipe 15a and the gas supply pipe 15b will be described.

[Optimization of the volume ratio of the gas supply pipe]

In this embodiment, the arrangement of the orifice 23 in the pressure type flow control device 20 and the control valve 21 and the second valve VL2 before and after it is changed to change the volume ratio V _{1 of the} gas supply pipe 15a and the gas supply pipe 15b /V _{2 to} be appropriate. Specifically, in the comparative example, the volume ratio V ₁ /V ₂ of the gas supply pipe 15 a and the gas supply pipe 15 b is 3/2, while in this embodiment, the volume of the gas supply pipe 15 a and the gas supply pipe 15 b is The arrangement of the control valve 21 and the second valve VL2 is changed so that the ratio V ₁ /V ₂ is 9/1 or more.

For example, the volume ratio V ₁ /V _{2 of the} gas supply pipe 15 a and the gas supply pipe 15 b is set to 3/2 on the condition that the pressures P ₁ and P ₂ slightly satisfy the critical expansion pressure condition P ₁ >2×P ₂ . At this time, the state of the pressures P ₁ and P ₂ after the gas supply is stopped, that is, after the control valve 21 and the second valve VL2 are closed is shown in FIG. 5. In FIG. 5, the pressure P _{1 of the} gas supply pipe 15a fluctuates greatly, and it takes time to stabilize. As a result, in the control of starting or stopping the gas supply, a gas peak corresponding to the changed pressure P ₁ is generated, making it difficult to control the gas flow rate. In addition, when the gas flow rate is changed, it takes time to stabilize the pressure P1.

On the other hand, the volume ratio V ₁ /V _{2 of the} gas supply pipe 15 a and the gas supply pipe 15 b is set to 90/1 with the pressures P ₁ and P ₂ slightly satisfying the critical expansion pressure condition P ₁ >2×P _2. . At this time, the state of the pressures P ₁ and P ₂ after the gas supply is stopped, that is, after the control valve 21 and the second valve VL2 are closed is shown in FIG. 6. In FIG. 6, the pressure P _{1 of the} gas supply pipe 15a hardly changes, and it can be seen that the pressure stabilizes immediately. Moreover, this also shows that when the gas flow rate is changed, the time from the pressure P ₁ to the stabilization is very short.

The luminous intensity curve I3 shown in the embodiment of FIG. 4 shows the present embodiment of the pressure type flow control device 20 in which the volume ratio V ₁ /V _{2 of the} gas supply pipe 15a and the gas supply pipe 15b is set at 90/1 Gas supply control method to supply gas luminous intensity in the chamber C when supplying gas. By this, since the volume ratio V ₁ /V _{2 of the} gas supply pipe 15 a and the gas supply pipe 15 b is set to 90/1, the time from the pressure P ₁ to a stable time can be shortened, so after starting the gas supply, The gas can be smoothly supplied into the chamber C. With this, the two-stage start of the gas flow shown in the comparative example of FIG. 4 can be eliminated.

[Pressure in equilibrium P1]

When the volume ratio V ₁ /V ₂ of the gas supply pipe 15 a and the gas supply pipe 15 b is changed, a graph showing the equilibrium state pressure of the pressure P ₁ in the gas supply pipe 15 a and the gas supply pipe 15 b relative to the initial pressure is shown in the figure 7. As described above, the equilibrium pressure/initial pressure of the pressure P ₁ when the volume ratio V ₁ /V _{2 of the} gas supply pipe 15a and the gas supply pipe 15b is set to 90/1 is slightly closer to 100% as shown by Re in FIG. 7 Of the value. The numerical values shown in FIG. 7 specifically, the equilibrium pressure/initial pressure of the pressure P1 is 62% when the volume ratio V ₁ /V ₂ is 1.5, and 75% when the volume ratio V ₁ /V ₂ is 3.0. The ratio V ₁ /V ₂ is 90% at 9.0, the volume ratio V ₁ /V ₂ is 18.0 at 95%, the volume ratio V ₁ /V ₂ at 30.0 is 97% at the volume ratio V ₁ /V ₂ is 99% when it is 90.0.

At this time, the volume ratio V ₁ /V _{2 is} set to 90/1, and the etching rate E/R after the etching process in the chamber C is set to the volume ratio V1/V2 to 3/2, and the etching process in the chamber C After that, the etching rate E/R changes to 20%.

Since the volume ratio V ₁ /V _{2 is} set at 90/1, and the waveform at the beginning of the two stages I1 and I2 shown in the comparative example of FIG. 4 is not observed, it is desirable to suppress the change in the etching rate E/R to Within 5%, the ratio of the equilibrium state of the pressure P1 to the initial state is preferably 90% to 100%. That is, the volume ratio V ₁ /V _{2 of the} gas supply pipe 15a and the gas supply pipe 15b may be set to 9/1 or more.

That is, the volume ratios V ₁ : V _{2 in} FIG. 9 may be set so that the volumes V ₁ and V ₂ are 9 parts or more (points and diagonal parts). However, due to physical limitations related to the processing of the gas supply pipes 15a and 15b, it is preferable to set the volumes V ₁ and V _{2 such} that the volume ratio V ₁ :V ₂ is 200:1 or less. In fact, when the volume ratio V ₁ : V ₂ is 9:1 or more, 200:1 or less, and the volume V ₁ is in the range of 0.09 to 2.0 (cc), the volume V ₂ is in the range of 0.01 to 0.2 (cc). That is, the effective range of the ratio of the volume V ₁ /V ₂ is set in the area Ar.

As described above, in this embodiment, the gas supply to the chamber C and the gas supply stop are performed by the opening and closing operation of the second valve VL2 provided on the downstream side of the orifice 23 in the pressure type flow control device 20 control. At this time, in order to relieve the pressure change at the time of gas stop by the structure unique to the pressure type flow control device 20, the volume of the control valve 21 and the second valve VL2 from the orifice 23 to the front and back is smaller than that of the comparative example .

Thereby, the pressure-type flow control device 20 can be used to rapidly raise the gas supplied into the chamber C to a predetermined flow rate. According to this embodiment, the responsiveness of the gas is improved, and the gas can be switched at high speed. That is, the gas control method according to the present embodiment using the pressure-type flow control device 20 according to the present embodiment is effective for a program (Gas Pulse) that repeats gas supply and gas supply stop at high speed.

In addition, in this embodiment, since the gas responsiveness is improved, the time for the gas flow rate in the chamber C to be stabilized can be shortened, and an improvement in productivity can be achieved.

When the predetermined time T in (a) of FIG. 2 described above becomes longer, the gas flow rate supplied to the chamber C becomes stable. However, during the opening time of the gas supply valve, the actual gas supply time becomes shorter. As a result, if the predetermined time T becomes longer, the yield will decrease. FIG. 8 shows an example of the relationship between the predetermined time T and the etching rate related to this embodiment. The horizontal axis of FIG. 8 shows the ratio T/S of the predetermined time T to the time S in step 2. The vertical axis of FIG. 8 shows the etching rate (E/R) with respect to T/S.

As a result, the longer the predetermined time T, the lower the etching rate. (S-T)/S is smaller than 90%, that is, when T/S is larger than 0.1, the decrease in etching rate cannot be ignored. Therefore, the predetermined time T needs to be 1/10 or less of the step time S.

Moreover, in this embodiment, after the gas supply is started by the control of the second valve VL2, the flow rate of the gas supplied to the chamber C can be quickly stabilized to the desired flow rate. Therefore, as long as the matching device 13a is set at the integrated position after the flow rate is stabilized, the reflected wave of the high-frequency power output from the high-frequency power supply 13 can be suppressed, and the processing stability of the semiconductor manufacturing apparatus 10 can be improved.

In addition, in this embodiment, the gas with no control information as in the comparative example is not introduced into the chamber C. Therefore, the difference in the supply of gas to the chamber C due to the individual difference of the pressure type flow control device 20 and the individual difference of the semiconductor manufacturing device 10 can be absorbed, and the semiconductor manufacturing device 10 can be stably processed.

[Urgent Interactive Program]

Finally, an example of a procedure for repeating the gas supply and the gas supply stop at high speed will be described with reference to FIG. 10 for a quick interactive procedure. In the rapid interactive program using the gas supply control method of this embodiment shown in FIG. 10, the etching process and the deposition process are interactively and rapidly executed. However, this is only an example of an urgent interactive program, and the types of programs are not limited to this. In addition, during the execution of the rapid interactive program, the first valve VL1 is controlled to be constantly opened, and the control valve 21 is controlled to be constantly controlled. The processing of the urgent interactive program shown in FIG. 10 is controlled by the control circuit 22.

When the process of FIG. 10 is started, first, the second valve VL2 is controlled to be opened, and the first gas is injected (step S10). Next, high-frequency power is applied, and the etching process is performed with the first gas (step S12). Next, the second valve VL2 is controlled to be closed (step S14).

Next, the second valve VL2 is controlled to be opened, and the second gas is injected (step S16). Next, high-frequency power is applied, and the deposition process is performed by the second gas (step S18). Next, the second valve VL2 is controlled to be closed (step S20).

Next, it is determined whether it is necessary to further circulate the interactive program (step S22). If it is determined to be necessary, the process returns to step S10 and repeats steps S10 to S22. In step S22, if it is judged that it is unnecessary to further execute the loop of the interactive program, the processing is ended.

According to the urgent interactive program related to the present embodiment, following the opening and closing control of the second valve VL2, a predetermined flow of gas is quickly supplied into the chamber C, so a good program can be realized. Moreover, it is not necessary to consider the control of the time when the gas reaches the chamber C. In this way, the gas supply control method of this embodiment, which can improve gas responsiveness, can be effectively used especially in a rapid interactive program that repeats gas supply and gas supply stop at high speed.

However, regarding the allowable range of the predetermined time T relative to the time S in step 2 of (a) of FIG. 2, as shown in FIG. 8, the longer the predetermined time T (the larger T/S), the etch rate (E/R ) Lower. (S-T)/S is smaller than 90%, that is, when T/S is larger than 0.1, the decrease in etching rate cannot be ignored. Therefore, the predetermined time T needs to be 1/10 or less of the step time S.

(Modification)

Next, an example of a gas supply control method related to a modification of this embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram for explaining a gas supply control method according to a modification of this embodiment. FIG. 12 is a diagram showing an example of the overall configuration of a gas supply control system related to a modification of this embodiment.

As described above, in the gas supply control method according to the present embodiment, in the process of switching the gas at a high speed, the stability can be improved and the speed can be improved. However, as shown in FIG. 11(a), when the first gas is supplied in step 2 following step 1, and the second gas is supplied in step 4 after the gas supply is stopped in step 3, the first gas is generated. The flow rate is larger than the flow rate of the second gas. That is, the step 4 of circulating the second gas cannot initially control the flow rate of the gas flowing to the second valve VL2, and a SPIKE S will occur, which deteriorates the stability and controllability when the gas is supplied. This is the pressure in the step 2 after the end of the supply of the first gas step gas supply pipe 15a 3 is _1, the pressure in the second supply the necessary gases Step 4 gas supply pipe 15a P is P ₁ ', the first The flow rate of 1 gas is larger than that of the second gas, and there is a relationship of P ₁ >P ₁ ′. This can be said that even if the pressure in the gas supply pipe 15b is still the same, the pressure in the gas supply pipe 15b in step 3 is P ₂ , and the pressure in the necessary gas supply pipe 15b in step 4 is P ₂ ′, there is P ₂ > relationship P ₂ 'of. Thus, the start of step 4, enclosed in 'and the pressure P _2' a higher discharge pressure P and P gas to the gas supply pipe ₁₂ and 15a of the second gas supply pipe 15b to the pressure necessary to more P _1. As a result, shortly after switching from step 3 to step 4, at the beginning of step 4, the flow rate of the gas flowing through the second valve VL2 increases, and a failure S occurs.

Therefore, in the gas supply control system 1 according to the modification of the present embodiment, as shown in FIG. 12, a vacuum suction line 28 is provided in the gas supply pipe 15a between the control valve 21 and the second valve VL2. The vacuum suction line 28 is provided with a vacuum suction valve VL3. By opening the vacuum suction valve VL3, the exhaust of the exhaust device 29 connected to the vacuum suction line 28 can be controlled.

Specifically, in step 3 between step 2 and step 4 in FIG. 11(b), the vacuum suction valve VL3 is controlled to be opened. Thereby, the inside of the gas supply pipe 15a and the gas supply pipe 15b can be evacuated by the exhaust device 29 to become the pressure P ₁ of the gas supply pipe 15a of step 3 ≦ the pressure P of the gas supply pipe 15a of step 4 ₁ ', and the pressure P ₂ of the gas supply pipe 15v of step 3 ≦ the pressure P ₂ 'of the gas supply pipe 15b of step 4. Therefore, even in the case where the first gas flow rate is greater than the second gas flow rate, in the step 4 of supplying the second gas, the gas flow rate flowing through the second valve VL2 in FIG. 11(b) will be fixed without failure S. In this way, even in the process of supplying gas with different flow rates, the stability and controllability during gas supply can be further improved.

[Urgent Interactive Program]

Next, a brief interactive program related to a modification of this embodiment will be briefly described with reference to FIG. 13. In the emergency interactive program using the gas supply control method according to the modification of the embodiment shown in FIG. 13, the etching program and the deposition program are interactively and rapidly executed. The processing of the urgent interactive program shown in FIG. 13 is controlled by the control circuit 22.

When the process of FIG. 13 is started, first, the second valve VL2 is controlled to be opened, and the first gas is injected (step S10). Next, high-frequency power is applied, and the etching process is performed with the first gas (step S12). Next, the second valve VL2 is controlled to be closed, and the gas supply pipe 15a and the gas supply pipe 15b are evacuated while no gas is being supplied (step S30).

Next, the second valve VL2 is controlled to be opened, and the second gas is injected (step S16). Next, high-frequency power is applied, and the deposition process is performed by the second gas (step S18). Next, the second valve VL2 is controlled to be closed, and the gas supply pipe 15a and the gas supply pipe 15b are evacuated while the gas is not being supplied (step S32).

Next, it is determined whether it is necessary to further circulate the interactive program (step S22). If it is determined to be necessary, the process returns to step S10 and repeats steps S10 to S22. In step S22, it is judged further If there is no need to rush through the loop of the interactive program, this process will end.

According to the urgent interactive program related to the modification of the present embodiment, the opening and closing control of the second valve VL2 and the evacuation of the gas supply pipe 15a and the gas supply pipe 15b are performed. By this, even if the procedures of different gas flow rates are performed before and after, the high-pressure gas will be evacuated from the vacuum suction line 28 while the gas is not being supplied, and even if a small flow of gas is supplied in the next step, the predetermined The flow of gas is quickly supplied into the chamber C. Therefore, according to the urgent interactive program related to the modification, the stability and controllability in the gas supply can be further improved, and a good program can be realized. In particular, in a rapid interactive program that repeats gas supply and gas supply stop at high speed, the gas supply control method related to the modification of this embodiment that can improve gas responsiveness can be effectively used.

[Change of the interactive program urgently]

Next, the change of the rapid interactive program related to the modification of this embodiment will be briefly explained with reference to FIG. 14. In the urgent interactive program using the gas supply control method according to the modification of the embodiment shown in FIG. 14, the etching program and the deposition program are interactively and rapidly executed. The processing of the urgent interactive program shown in FIG. 14 is controlled by the control circuit 22.

When the process of FIG. 14 is started, first, the second valve VL2 is controlled to be opened, and the first gas is injected (step S10). Next, high-frequency power is applied, and the etching process is performed with the first gas (step S12). Next, the second valve VL2 is controlled to be closed (step S14).

Next, it is determined whether the first gas flow rate is greater than the second gas flow rate (step S40). When the first gas flow rate is greater than the second gas flow rate, the gas supply pipe 15a and the gas supply pipe 15b are evacuated while no gas is being supplied (step S42). When the first gas flow rate is less than the second gas flow rate, evacuation is not performed.

Next, the second valve VL2 is controlled to be opened, and the second gas is injected (step S16). Next, high-frequency power is applied, and the deposition process is performed by the second gas (step S18). Next, the second valve VL2 is controlled to be closed (step S20).

Next, it is determined whether it is necessary to further cycle through the interactive program (step S22), and if it is determined to be necessary, it is determined whether the first gas flow rate is greater than the second gas flow rate (step S44). When the first gas flow rate is greater than the second gas flow rate, the gas supply pipe 15a and the gas supply pipe 15b will be evacuated while no gas is being supplied (step S42), then return to step S10 and repeat steps S10 and after deal with. When the first gas flow rate is equal to or less than the second gas flow rate, evacuation is not performed, and then the process returns to step S10 and the processing after step S10 is repeated.

On the other hand, if it is judged in step S22 that further rapid looping of the interactive program is unnecessary, this process is ended.

According to the modification of the rapid interactive program related to the modification of this embodiment, only when the first gas flow rate is greater than the second gas flow rate, the gas supply pipe 15a and the gas supply pipe 15b are pumped during the period when no gas is supplied vacuum. With this, even in the case where the procedures of different gas flow rates are performed before and after, the gas of a predetermined flow rate can be quickly supplied into the chamber C. Therefore, according to the urgent interactive program related to the modification, the stability and controllability in the gas supply can be further improved, and a good program can be realized. In addition, in the case where the first gas flow rate is less than the second gas flow rate, it is predicted that failure S will hardly occur, so in the step of not supplying gas (for example, step 3 of FIG. 11 ), the gas supply pipe 15a and the gas are not allowed The supply pipe 15b is evacuated. As a result, the time of step 3 can be shortened and productivity can be improved compared to the urgent interactive program shown in FIG. 13.

Although the gas supply control method has been described above with the above embodiment, the gas supply control method related to the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the present invention. The matters described in the above plural embodiments can be combined as long as there is no contradiction.

For example, a semiconductor manufacturing device using the gas supply control method according to the present invention may be a capacitively coupled plasma (CCP: Capacitively Coupled Plasma) device, an inductively coupled plasma (ICP: Inductively Coupled Plasma) device, or use a wire slot Plasma processing device for antenna, spiral wave excitation plasma (HWP: Helicon Wave Plasma) device, electron cyclotron resonance plasma (ECR: Electron Cyclotron Resonance Plasma) device, etc.

In addition, the substrate processed by the semiconductor manufacturing apparatus according to the present invention is not limited to a wafer, and may be, for example, a large substrate for a flat panel display (Flat Panel Display), an EL element, or a substrate for a solar cell.

I1‧‧‧stage

I2‧‧‧stage

I3‧‧‧Luminous intensity curve

P ₁ ‧‧‧ pressure

P ₂ ‧‧‧ pressure

Claims (5)

A gas supply control method using a pressure control type flowmeter provided in a gas supply line, a first valve provided on the gas supply line upstream of the pressure control type flowmeter, and a pressure provided on the gas supply line less than the pressure The control type flowmeter requires a gas supply control method of the second valve on the downstream side. The pressure control type flowmeter has a control valve connected to the first valve and the second valve, and is provided on the control valve and the second valve Orifice between; the volume V ₁ of the gas supply pipe between the orifice and the control valve and the volume V ₂ of the gas supply pipe between the orifice and the second valve are V ₁ /V the relation ₂ ≧ 9; based gas supply pipe during the pressure P ₁ between the orifice and the second valve with the pressure of the gas supply pipe between the control valve and the orifice P ₂ P ₁ is maintained in the feed gas >2×P ₂ ; open the first valve, and control the supply of gas through the opening and closing control of the second valve in a state where the control valve is controlled. For example, the gas supply control method according to item 1 of the patent application scope, wherein the volume V ₁ and the volume V ₂ have a relationship of V ₁ /V ₂ ≦200. For example, the gas supply control method according to item 1 or 2 of the patent application scope is to open the first valve, and in a state where the control valve is controlled, the first valve is alternately supplied by the opening and closing control of the second valve For the gas and the second gas, the procedure of the first gas and the procedure of the second gas are carried out alternately. For example, in the gas supply control method of claim 3, between the step of supplying the first gas and the step of supplying the second gas, in the step of not supplying gas, the second valve and the control valve The inside of the gas supply pipe is evacuated. For example, in the gas supply control method of claim 3, between the step of supplying the first gas and the step of supplying the second gas, in the step of not supplying gas, the flow rate of the first gas is lower than that of the first 2 When the flow rate of the gas is large, in the step of not supplying gas, the inside of the gas supply pipe between the second valve and the control valve is evacuated.

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