TWI605513B - Vacuum device, pressure control method, and etching method - Google Patents

Description

Vacuum device, pressure control method thereof and etching method

The present invention relates to a vacuum apparatus, a pressure control method, and an etching method for plasma treatment of a target object.

In the manufacturing process of an FPD (flat panel display), various plasma treatments such as plasma etching, plasma ashing, and plasma film formation are performed on the FPD substrate. As a device for performing the plasma treatment, for example, a parallel plate type plasma processing device or an inductively coupled plasma (ICP) processing device is known. These plasma processing apparatuses are configured as a vacuum apparatus that performs a process of reducing the pressure inside the processing container to a vacuum state.

As a conventional technique for pressure control of a vacuum apparatus, Patent Document 1 proposes a method of fixedly maintaining the conductivity of an exhaust path while simultaneously changing a flow rate of a gas supplied into a processing container by a mass flow controller (MFC). . Further, Patent Document 2 proposes a method of adjusting the pressure inside the processing container by flowing a ballast gas having a fixed flow rate from the throttle valve of the exhaust path to the upstream side.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Laid-Open Patent Publication No. 2002-57089 (Fig. 3, etc.)

[Patent Document 2] Japanese Laid-Open Patent Publication No. Hei 10-11152 (Fig. 1, etc.)

In recent years, in order to process a large-sized FPD substrate, the processing container has also become large. Therefore, it is not sufficient to have only one vacuum pump for decompressing and decompressing the inside of the processing container, and it is necessary to have a plurality of vacuum pumps. In the upstream side of the exhaust direction of the vacuum pumps, an automatic pressure control valve (hereinafter referred to as "APC valve") is provided, and the inside of the processing container is adjusted by automatically adjusting the conductivity of the exhaust path. pressure. For example, in a plasma etching apparatus, a process gas is supplied to a processing vessel by a mass flow controller during a process, and at the same time, the conductivity of the exhaust path is adjusted by an APC valve to control the desired The method of process pressure.

However, in plasma etching, in a process in which the process gas is consumed and the gas volume is reduced, the gas volume is rapidly increased after the end of the etching. This phenomenon is caused by the fact that when the etching progresses and the etching target film disappears while the etching target film is present, the processing gas that is consumed by the reaction with the target film is not consumed. When the volume changes rapidly, the opening degree of the APC valve will be fully open, and the pressure control of the APC valve will not catch up. As a result, there is a problem that the pressure in the processing container rises sharply with the completion of the etching. After etching The sudden increase in pressure is a cause of excessive radicals, and there is a case where the shape of the pattern formed on the surface of the substrate collapses or the like. In order to cope with the above-described pressure change, it is necessary to increase the number of sets of the vacuum pump and the APC valve to ensure sufficient exhaust capability, which causes one of the increase in the number of parts and the increase in cost.

Therefore, the object of the present invention is mainly to suppress a sudden change in pressure in a vacuum apparatus for performing pressure adjustment in a processing container by an APC valve.

A vacuum apparatus according to the present invention includes: a processing container that can accommodate a target object and maintains a vacuum inside; a gas supply source supplies a processing gas to the processing chamber via a gas supply path; and a flow rate adjusting device is provided in the gas supply path And adjusting a supply flow rate of the processing gas; a pressure detecting device detecting a pressure in the processing container; and an exhaust device connected to the processing container via an exhaust path; the APC valve being disposed in the exhaust path and according to the pressure The pressure value detected by the detecting device automatically adjusts the opening degree; the opening degree monitoring unit monitors the opening degree of the APC valve; and the flow rate control unit adjusts the flow regulating device according to the monitoring result of the opening degree monitoring unit The flow of gas supplied.

In the vacuum apparatus of the present invention, the flow rate control unit may control the flow rate adjustment by comparing the opening degree of the APC valve with a predetermined threshold value to reduce the supply flow rate of the processing gas. Device.

Further, the vacuum apparatus of the present invention further includes a counter unit for counting the number of times the opening degree of the APC valve exceeds a first critical value, and the flow rate control unit may cause the processing gas when the count value exceeds a second critical value The flow rate adjustment device is controlled in such a manner that the supply flow rate is reduced.

Further, the vacuum apparatus of the present invention further includes: an opening degree calculation unit that calculates an increase rate of the opening degree of the APC valve within a predetermined elapsed time period, and the flow rate control unit may increase the rate of opening and closing beyond the third limit At the time of the value, the flow rate adjusting device is controlled such that the supply flow rate of the processing gas is reduced.

The vacuum apparatus of the present invention may be an etching apparatus that etches a target object.

The vacuum device to be processed according to the present invention may be a substrate for FPD.

The pressure control method of the present invention is a method for controlling the pressure of the processing container in a vacuum apparatus, the vacuum apparatus comprising: a processing container capable of accommodating the object to be processed and maintaining a vacuum inside; and a gas supply source via a gas supply path pair a processing gas is supplied into the processing chamber; a flow rate adjusting device is provided in the gas supply path to adjust a supply flow rate of the processing gas; a pressure detecting device detects a pressure in the processing container; and the exhaust device is connected via an exhaust path And the APC valve is disposed in the exhaust path, and automatically adjusts the opening degree according to the pressure value detected by the pressure detecting device. Pressure control method The opening degree of the APC valve is monitored, and the flow rate of the gas supplied by the flow regulating device is adjusted according to the result.

The pressure control method of the present invention can also be controlled in such a manner that the supply flow rate of the processing gas is reduced by comparing the opening degree of the APC valve with a predetermined threshold value.

In the pressure control method of the present invention, when the number of times the opening and closing degree of the APC valve exceeds the first critical value is counted, and when the count value exceeds the second critical value, the supply flow rate of the processing gas may be decreased. control.

The pressure control method of the present invention may be controlled such that the rate of increase in the degree of opening of the APC valve exceeds the third critical value while reducing the supply flow rate of the processing gas within a predetermined elapsed time range.

In the pressure control method of the present invention, the vacuum device may be an etching device that etches the object to be processed.

In the pressure control method of the present invention, the object to be processed may be a substrate for FPD.

In the etching method of the present invention, the object to be processed is etched by using an etching apparatus, and the etching apparatus includes a processing container configured to accommodate the object to be processed and to maintain a vacuum inside; and a gas supply source via the gas supply path Supplying a processing gas into the processing chamber; a flow rate adjusting device provided in the gas supply path to adjust a supply flow rate of the processing gas; a pressure detecting device detecting a pressure in the processing container; and an exhaust device passing through the exhaust path Connected to the aforementioned processing container; And the APC valve is disposed in the exhaust path, and automatically adjusts the opening degree according to the pressure value detected by the pressure detecting device. The etching method may also monitor the opening degree of the APC valve and adjust the gas flow rate supplied by the flow regulating device based on the result.

In the etching method of the present invention, the supply flow rate of the processing gas can be reduced by comparing the opening degree of the APC valve with a predetermined critical value.

In the etching method of the present invention, when the number of times the opening degree of the APC valve exceeds the first critical value is counted, and the count value exceeds the second critical value, the supply flow rate of the processing gas may be decreased.

The etching method of the present invention may be controlled such that the supply rate of the processing gas is reduced when the rate of increase of the opening degree of the APC valve exceeds the third critical value within a predetermined elapsed time range. .

According to the present invention, the opening degree of the APC valve is mainly monitored in a vacuum apparatus for performing pressure adjustment in the processing container by the APC valve, and the flow rate of the processing gas introduced into the processing container is adjusted based on the result. For example, when the degree of opening and closing is increased, the gas flow rate is decreased, and the pressure increase in the processing container is suppressed by suppressing the flow rate of the processing gas, whereby the pressure rise in the processing container can be alleviated. Moreover, since the increase in the opening degree of the APC valve is before the pressure in the processing container rises, the processing gas flow is compared with the pressure measurement result in the processing container. The quantity changes and is more responsive. Therefore, according to the present invention, in the large-sized vacuum apparatus, the pressure control in the processing container can be surely performed without increasing the number of the vacuum pump and the APC valve.

1‧‧‧Processing container

1a‧‧‧ bottom wall

1b‧‧‧ side wall

1c‧‧‧ cover

11‧‧‧Base

12‧‧‧Substrate

13,14‧‧‧ Sealing members

15‧‧‧Insulating components

31‧‧‧ sprinkler

33‧‧‧ gas diffusion space

35‧‧‧ gas discharge hole

37‧‧‧ gas inlet

39‧‧‧Processing gas supply pipe

41‧‧‧ valve

43‧‧‧The mass flow controller

45‧‧‧ gas supply source

51‧‧‧Exhaust opening

53‧‧‧Exhaust pipe

53a‧‧‧Flange

55‧‧‧APC valve

57‧‧‧Exhaust device

61‧‧‧ pressure gauge

71‧‧‧Power supply line

73‧‧‧matching box (M.B.)

75‧‧‧High frequency power supply

100‧‧‧ plasma etching device

Fig. 1 is a cross-sectional view schematically showing the configuration of a plasma etching apparatus according to a first embodiment of the present invention.

Fig. 2 is a block diagram showing a hardware configuration of a control unit of a plasma etching apparatus according to an embodiment of the present invention.

Fig. 3 is a block diagram showing the hardware configuration of the device controller of Fig. 2.

Fig. 4 is a block diagram showing the function of the device controller of Fig. 2.

Fig. 5 is a flow chart showing an example of a procedure of a pressure control method according to a first embodiment of the present invention.

Fig. 6 is a view showing a change in the elapsed time of the pressure in the processing container and the opening degree of the APC valve after the plasma etching treatment of the etching target film by a conventional method.

Fig. 7 is a view similar to Fig. 6 showing a change in the elapsed time of plasma generated in the processing container during the plasma etching process.

Fig. 8 is a view for explaining a change in the opening degree of the APC valve and a change in the passage time of the process gas caused by the pressure control method according to the first embodiment of the present invention.

Fig. 9 is a view showing the results of an experiment in which the pressure control method according to the first embodiment of the present invention is applied to actual plasma etching treatment.

Fig. 10 is a functional block diagram showing a functional configuration of a device controller according to a second embodiment of the present invention.

Fig. 11 is a flow chart showing an example of a procedure of a pressure control method according to a second embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]

Fig. 1 is a cross-sectional view showing a schematic configuration of a plasma etching apparatus according to a first embodiment of the processing apparatus of the present invention. Fig. 2 is a cross-sectional view showing the main part of Fig. 1 in an enlarged manner. As shown in FIG. 1 , the plasma etching apparatus 100 is a capacitive coupling type parallel plate plasma etching apparatus which etches a to-be-processed object, such as the FPD glass substrate (Hereafter, it is only described as "substrate") S. Further, the FPD is exemplified by a liquid crystal display (LCD), an electroluminescence (EL) display, a plasma display panel (PDP), and the like.

The plasma etching apparatus 100 is a processing container 1 which is formed of aluminum which is anodized (aluminum-treated) inside and formed into a rectangular tube shape. The main body (container body) of the processing container 1 is configured by a bottom wall 1a and four side walls 1b (only two are shown). Also, in the processing container 1 A lid body 1c is joined to the upper portion of the body. Although not shown in the drawings, the side wall 1b is provided with a gate valve opening and a gate valve for sealing the substrate transfer opening.

The lid body 1c is configured to be switchable with respect to the side wall 1b by a switch mechanism (not shown). In a state where the lid body 1c is closed, the joint portion of the lid body 1c and each side wall 1b is sealed by the O-ring 3, and the airtightness in the processing container 1 is maintained.

A frame-shaped insulating member 10 is disposed at the bottom of the processing container 1. The insulating member 10 is provided with a susceptor 11 on which a mounting table of the substrate S can be placed. The base 11 of the lower electrode is also provided with a base material 12. The substrate 12 is formed of a conductive material such as aluminum or stainless steel (SUS). The base material 12 is disposed on the insulating member 10, and a sealing member 13 such as an O-ring is provided at a joint portion of the two members to maintain airtightness. The airtightness is also maintained between the insulating member 10 and the bottom wall 1a of the processing container 1 by a sealing member 14 such as an O-ring. The side periphery of the substrate 12 is surrounded by the insulating member 15. Thereby, the insulation of the side surface of the susceptor 11 can be ensured, and abnormal discharge at the time of plasma processing can be prevented.

Above the susceptor 11, a head 31 which is parallel to the susceptor 11 and has an upper electrode function is provided. The head 31 is supported by a lid 1c of the upper portion of the processing container 1. The head 31 is hollow, and a gas diffusion space 33 is provided inside. Further, a plurality of gas discharge holes 35 for discharging the processing gas are formed on the lower surface of the head 31 (the surface facing the susceptor 11). The head 31 is in a grounded state, and together with the susceptor 11, constitutes a pair of parallel plate electrodes.

A gas introduction port 37 is provided in the vicinity of the center of the upper portion of the head 31. A processing gas supply pipe 39 is connected to the gas introduction port 37. In the processing gas supply pipe 39, a gas supply source 45 for supplying a processing gas for etching is connected via two valves 41, 41 and a mass flow controller (MFC) 43. As the processing gas, for example, a rare gas such as an Ar gas or the like can be used in addition to a halogen-based gas or an O ₂ gas.

The bottom wall 1a in the processing container 1 is formed with an exhaust opening 51 penetrating through a plurality of portions (for example, eight places). An exhaust pipe 53 is connected to each of the exhaust openings 51. The exhaust pipe 53 has a flange portion 53a at its end, and is fixed in a state in which an O-ring (not shown) is interposed between the flange portion 53a and the bottom wall 1a. An APC valve 55 is provided in the exhaust pipe 53, and the exhaust pipe 53 is connected to the exhaust device 57. The exhaust device 57 is provided with a vacuum pump such as a turbo molecular pump, whereby the inside of the processing container 1 can be vacuum-pumped to a predetermined reduced pressure environment. A total of eight APC valves 55 provided in each of the exhaust pipes 53 are constituted by one main valve and seven driven valves, and each of the driven valves is operated in conjunction with the main valve. That is, the eight APC valves 55 are synchronized with each other to perform a switching operation.

Further, the plasma etching apparatus 100 is provided with a pressure gauge 61 that measures the pressure in the processing container 1. The pressure gauge 61 is connected to the main valve of the eight APC valves 55, and immediately supplies the measurement result of the pressure in the processing container 1 to the APC valve 55. The APC valve 55 automatically changes the degree of opening and closing according to the measurement result of the pressure gauge 61, and automatically adjusts the conductivity of the exhaust pipe 53.

A power supply line 71 is connected to the substrate 12 of the susceptor 11. The power supply line 71 is connected to the high frequency power supply 75 via a matching box (M.B.) 73. Thereby, it is possible to apply a high frequency electric power such as 13.56 MHz from the high frequency power source 75. The force is supplied to the susceptor 11 as a lower electrode. Further, the power supply line 71 is introduced into the processing container 1 through the power supply opening 77 formed through the bottom wall 1a as a through opening.

Each component of the plasma etching apparatus 100 is configured to be connected to the control unit 80 and controlled. A control unit 80 for including the plasma etching apparatus 100 of the present embodiment in the substrate processing system of the present embodiment will be described with reference to Fig. 2 . FIG. 2 is a block diagram showing the hardware configuration of the control unit 80. As shown in FIG. 2, the control unit 80 includes a device controller (hereinafter referred to as "EC") 81; a plurality of (only two of them are shown in FIG. 2, but they are not The present invention is limited to a module controller (hereinafter referred to as "MC") 83; and a switching hub (HUB) 85 to which EC81 and MC83 are connected.

The EC81 is a main control unit (main control unit) that controls a plurality of MC83s and controls the overall operation of the substrate processing system. Each of the plurality of MC83 systems controls the sub-control unit (slave controller) that operates each module including the plasma etching apparatus 100 under the control of the EC81. The switching hub 85 switches the MC 83 connected to the EC 81 in response to a control signal from the EC 81.

The EC81 controls the overall operation of the substrate disposal system by transmitting a control signal to each MC 83 by a control program for realizing various processes for the substrate S executed in the substrate processing system, and a processing program for recording processing condition data and the like. .

The control unit 80 further includes a subnet 87, a DIST (Distribution) board 88, and an input/output (hereinafter referred to as an I/O) module 89. Each MC83 is connected to the I/O module 89 via the subnet 87 and the DIST board 88.

The I/O module 89 has a plurality of I/O sections 90. The I/O unit 90 is connected to each terminal device of each module including the plasma etching apparatus 100. Although not shown, the I/O unit 90 is provided with an I/O board for controlling the input and output of the digital signal, the analog signal, and the serial signal. The control signals for the respective terminal devices are each output from the I/O unit 90. Further, the output signals from the respective terminal devices are each output from the I/O unit 90. In the plasma etching apparatus 100, a mass flow controller (MFC) 43, an APC valve 55, a pressure gauge 61, an exhaust device 57, and the like are cited as terminal devices connected to the I/O unit 90.

The EC 81 is connected to a computer 93 as an MES (Manufacturing Execution System) that manages a manufacturing process in which the entire substrate processing system 100 is installed via a LAN (Local Area Network) 91. The computer 93 cooperates with the control unit 80 of the substrate processing system 100, and feeds back the real-time information about the factory process to the core business system, and performs the judgment on the process in consideration of the load of the entire plant. The computer 93 can also be connected to an information processing unit such as another computer 95.

Next, an example of the hardware configuration of the EC 81 will be described with reference to Fig. 3 . The EC81 includes a main control unit 101, an input device 102 such as a keyboard or a mouse, an output device 103 such as a printer, a display device 104, a memory device 105, an external interface 106, and a bus bar 107 that connects the devices to each other. . The main control unit 101 includes a CPU (Central Processing Unit) 111, a RAM (Random Access Memory) 112, and a ROM (Read Only Memory) 113. If the memory device 105 is a memorable information, it is not limited to any The form may be, for example, a hard disk device or a compact disk device. Further, the memory device 105 records information on the computer-readable recording medium 115, and can read information from the recording medium 115. If the recording medium 115 is a memorable information, it is not limited to any form, and may be, for example, a hard disk, a compact disk, a flash memory, or the like. The recording medium 115 may be a recording medium on which the processing program of the plasma etching method of the embodiment is recorded.

In the EC 81, the CPU 111 uses the RAM 112 as a work area and executes a program stored in the ROM 113 or the memory device 105, whereby the plasma etching process can be performed on the substrate S in the plasma etching apparatus 100 of the present embodiment. Further, the hardware configuration of the computers 93 and 95 of Fig. 2 is also formed, for example, as shown in Fig. 3. Further, the hardware configuration of the MC 83 shown in FIG. 2 is formed, for example, as shown in FIG. 3, or a configuration in which the unnecessary constituent elements are removed from the configuration shown in FIG.

Next, the functional configuration of the EC 81 will be described with reference to Fig. 4 . Fig. 4 is a functional block diagram showing the function of the EC81. In the following description, the hardware configuration of the EC 81 is formed as shown in FIG. 3, and the reference numerals in FIG. 3 may be referred to. As shown in FIG. 4, the EC81 includes a processing control unit 121, an opening degree monitoring unit 122, an opening degree determination unit 123, an overrun counter 124, and an input/output control unit 125. These are implemented by the CPU 111 using the RAM 112 as a work area and executing a program stored in the ROM 113 or the memory device 105.

The processing control unit 121 transmits a control signal to each of the MCs 83 based on a processing program or a parameter stored in advance in the memory device 105, whereby the desired plasma etching process is performed in the plasma etching apparatus 100. Way to control. Further, the processing control unit 121 includes a flow rate control unit 121a.

The opening degree monitoring unit 122 monitors the opening degree of the APC valve 55 and acquires the information in real time. Specifically, the degree of opening and closing of the APC valve 55 is divided into, for example, 1000 stages of 0 to 1000, and the digital input (DI) information is immediately sent from the APC valve 55 to the opening degree monitoring unit 122 via the MC 83. Further, the opening degree monitoring unit 122 has a function of being attached to the APC valve 55 not only having the function of the EC 81 but also having the function of the EC 81. In this case, the MC83 of the plasma etching apparatus 100 can acquire the opening degree of the digital input (DI) information from the APC valve 55, and adopts the configuration of transmission to the EC81.

The opening degree determination unit 123 refers to the opening degree of the APC valve 55 that is immediately acquired by the opening degree monitoring unit 122 (or the opening degree monitoring function of the APC valve 55), and whether the opening degree exceeds a predetermined threshold (for example, the first critical value). Judgment. Here, the first threshold value refers to a degree in which the opening degree determination unit 123 refers to the storage device 105 in advance as a parameter.

The overrun counter 124 refers to the determination result of the opening degree determination unit 123, and when the degree of opening exceeds the first critical value, the count is counted every time the count is counted.

The input/output control unit 125 may perform control including: control from an input of the input device 102; or control of output from the output device 103; or control of display of the display device 104; or execution of external and external interfaces 106 Control of data input and output.

The flow rate control unit 121a controls the valves 41 and 41 and the mass flow controller (MFC) 43 and controls the supply from the gas supply source 45 to the processing container 1 The flow rate of the process gas within. Further, the flow rate control unit 121a performs a determination as to whether or not the excess count value counted by the overrun counter 124 exceeds a predetermined threshold value (second threshold value), and when the excess count value exceeds the second critical value, the mass flow controller is passed through the MC83. The (MFC) 43 sends a control signal to reduce the flow rate of the process gas by a predetermined amount. Thereby, the mass flow controller (MFC) 43 reduces the flow rate of the process gas by a predetermined amount. Here, the second threshold value means that the flow rate control unit 121a refers to the memory device 105 in advance as a part of the parameter or the processing program. Further, the amount of reduction in the processing gas (V0-V1) is also stored in the memory device 105 in advance by the flow rate control unit 121a as a part of the parameter or the processing program.

Next, the processing operation of the plasma etching apparatus 100 configured as described above will be described. First, in a state in which the gate valve (not shown) is opened, the substrate S as the object to be processed is carried into the processing container 1 by the chuck of the transfer device (not shown), and is transported to the susceptor 11 via the substrate transfer opening. . Thereafter, the gate valve is closed, and the inside of the processing container 1 is vacuum-pumped to a predetermined degree of vacuum by the exhaust unit 57.

Next, the valve 41 is opened, and the processing gas is introduced from the gas supply source 45 to the gas diffusion space 33 of the shower head 31 via the processing gas supply pipe 39 and the gas introduction port 37. At this time, the flow rate control of the processing gas is performed by the mass flow controller 43. The processing gas introduced into the gas diffusion space 33 is further uniformly discharged to the substrate S placed on the susceptor 11 via a plurality of discharge holes 35, and the pressure in the processing container 1 is maintained at a predetermined value.

In this case, high frequency power is supplied from the high frequency power source 75 via The matching box 73 is applied to the susceptor 11. Thereby, a high-frequency electric field is generated between the susceptor 11 as the lower electrode and the shower head 31 as the upper electrode, and the process gas is dissociated and plasmad. The substrate S is subjected to an etching treatment by the plasma.

After the etching treatment is applied, the application of the high-frequency power from the high-frequency power source 75 is stopped, and after the gas introduction is stopped, the inside of the processing chamber 1 is depressurized to a predetermined pressure. Then, the gate valve is opened, the substrate S is taken up from the susceptor 11 to the chuck of the transfer device (not shown), and the substrate S is carried out from the substrate transfer opening of the processing container 1. By the above operation, the plasma etching treatment for the substrate S is completed.

In the plasma etching process, the control unit 80 of the plasma etching apparatus 100 of the present embodiment monitors the opening degree of the APC valve 55, and detects an increase in the degree of opening as a signal for pressure rise. According to the detection result, the mass flow controller (MFC) 43 is feedback-controlled, thereby suppressing the supply amount of the processing gas, and the pressure increase in the processing container 1 is alleviated.

Hereinafter, the pressure control method of the present embodiment will be specifically described with reference to Figs. 5 to 9 . Fig. 5 is a flowchart showing an example of a procedure of the pressure control method of the embodiment executed by the control unit 80. Fig. 5 shows a procedure for suppressing the flow rate of the mass flow controller (MFC) 43 by monitoring the opening degree of the APC valve 55 until the flow rate of the mass flow controller (MFC) 43 is performed once.

First, in step S1, the EC 81 will acquire the opening degree of the APC valve 55. As described above, the degree of opening and closing of the APC valve 55 may be performed by the opening degree monitoring unit 122 of the EC 81 via the MC 83, or may be advantageous. The opening degree monitoring unit (not shown) attached to the APC valve 55 is sent to the EC 81 via the MC 83.

Next, in step S2, it is determined by the opening degree determination unit 123 of the EC 81 whether or not the opening degree of the APC valve 55 acquired in step S1 exceeds the first critical value. The opening degree determination unit 123 compares the acquired opening degree with the first critical value which is a parameter set in advance.

When the degree of opening is determined to exceed the first threshold value (Yes) in step S2, the overrun counter 124 counts the cumulative overrun count value based on the determination result from the opening degree determination unit 123 in step S3.

Next, in step S4, the flow rate control unit 121a determines whether or not the integrated value of the excess count value counted by the overrun counter 124 exceeds the second critical value. When the excess count value is determined to exceed the second critical value (Yes), in step S5, the flow rate control unit 121a sends a control signal to the mass flow controller (MFC) 43 via the MC 83 to reduce the flow rate of the processing gas. the amount. In the present embodiment, the reason why the number of times exceeding the first threshold value is exceeded by the counter 124 is as follows. During the plasma etching process, the pressure within the processing vessel 1 is varied with a fixed amplitude. Therefore, when the first critical value is exceeded once, it is not necessary to cause a large pressure change, but there is a case where appropriate pressure control cannot be performed. Here, in the present embodiment, the number of times exceeding the first critical value is counted by exceeding the counter 124, and the highly reliable pressure control is realized in the plasma etching apparatus 100 by comparison with the second critical value.

On the other hand, in step S2, the opening degree is judged as not When the first critical value (No) is exceeded, the process returns to step S1 and the procedures of steps S1 and S2 are repeated. The procedures of step S1 and step S2 are repeated until the degree of opening is judged to exceed the first critical value (Yes) or the plasma etching process is completed in step S2.

On the other hand, if it is determined in step S4 that the over-count value is not exceeded by the second threshold (No), the process returns to step S1 again and the procedures of steps S1 to S4 are repeated. The procedures of the steps S1 to S4 are repeated until the increase rate of the opening degree is judged to exceed the second critical value (Yes) or the plasma etching process is completed in the step S4.

According to the procedures of the above steps S1 to S5, the pressure change in the processing container 1 can be suppressed. Further, as described above, it is advantageous to use the over-counter 124 to count the number of times exceeding the first critical value after performing the pressure control with high reliability, for example, by making the first critical value larger than the processing container 1 during plasma etching. The general pressure change range within the flow rate is adjusted to determine whether the flow rate of the process gas exceeds the first critical value.

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When the plasma etching apparatus 100 is not particularly controlled, there is a case where the etching in the processing container 1 is rapidly increased after the etching is performed and the etching target film on the substrate S disappears. First, this phenomenon will be described with reference to FIGS. 6 and 7. FIG. 6 is a characteristic diagram showing temporal changes in the pressure in the processing container 1 and the opening degree of the APC valve 55 after etching the etching target film using the plasma etching apparatus 100. Figure 7 is a view showing the plasma light generated in the processing container 1 during the same plasma etching process as in Figure 6 A characteristic map of time changes. In addition, a titanium layer, an aluminum layer, and a titanium layer are laminated on the substrate S as an etching target film, and chlorine gas is used as an etching gas. In Fig. 7, the luminescence intensity of Ti at a wavelength of 335 nm and the luminescence intensity of Al at a wavelength of 396 nm are shown.

Referring to Fig. 6, the plasma etching starts before and after the horizontal axis is 10 seconds and ends before and after 125 seconds. It can be understood that during the plasma etching, the pressure in the processing container 1 is substantially maintained, but it rises between 100 and 110 seconds in the end period, and continues to rise until the end of the etching. On the other hand, the opening degree of the APC valve 55 is sharply increased between 100 and 110 seconds during the end of etching, and is maintained constant after 110 seconds (the opening degree is fully open).

On the other hand, referring to Fig. 7, the luminescence of Ti was observed by the progress of etching of the upper Ti film before and after the horizontal axis was 25 seconds. Next, with the etching of the intermediate Al film, the light emission of Al will dominate, and the light emission of Ti generated by the etching of the lower Ti film will be formed to the maximum amount before and after the disappearance of the light emission of Al before and after 100 seconds. Further, as shown in FIG. 7, the components of the respective films are overlapped in light emission because the etching is not performed uniformly on the surface of the substrate S of a large area, but is performed by, for example, etching from the periphery of the substrate S toward the center, and on the substrate S. The two layers of the upper and lower layers are simultaneously etched in the plane. In the period from 100 seconds to 110 seconds after the light emission of Ti is formed to the maximum amount, the lowermost Ti film of the etching target film having a three-layer structure is etched and disappears, and is formed on the base film of the substrate S. Will begin to slowly reveal the stage. Moreover, during the period of 100 seconds to 110 seconds, as shown in FIG. 6, it can be understood that when the opening degree of the APC valve 55 rises sharply and the opening degree is fully opened, there is no subsequent The pressure is controlled by the method, and the pressure in the processing vessel 1 will rise.

6 and 7, it is understood that the reason why the pressure in the processing container 1 rises is that the processing gas which is reacted with the target film is consumed while the film to be etched is present, and the etching target film disappears as the etching progresses. Will not consume. When the pressure change is suddenly caused as described above, as shown in Fig. 6, the opening degree of the APC valve 55 is maintained at the fully open state, and the pressure control in the processing container 1 of the APC valve 55 cannot be performed. Further, as is apparent from Figs. 6 and 7, the increase in the degree of opening of the APC valve 55 occurs earlier than the pressure rise in the processing container 1.

Here, in the pressure control method of the present embodiment and the plasma etching method using the same, the opening degree is increased before the pressure in the processing container rises in accordance with the procedures of steps S1 to S5 shown in FIG. 5 . The opening degree of the APC valve 55 is monitored, and based on the result, the flow rate of the processing gas introduced into the processing container 1 is changed. Here, FIG. 8 is an explanatory view showing a change in the opening degree of the APC valve and the elapsed time of the processing gas flow rate when the pressure control method of the present embodiment is carried out. C1, C2, C3, ... in Fig. 8 indicate a section in which the counter 124 is counted and the number of times the opening degree of the APC valve 55 exceeds the first critical value Th is accumulated. Further, t1, t2, and t3 on the horizontal axis of Fig. 8 indicate that when the count value generated by the overrun counter 124 exceeds the second critical value, the EC 81 sends a control signal to the mass flow controller (MFC) 43 via the MC 83 to process the gas. The flow rate is reduced by a predetermined amount of timing.

According to the procedure of steps S1 to S5 shown in FIG. 5, first, the degree of opening of the APC valve 55 before the pressure in the processing container 1 rises is monitored, and based on the result, the counter 124 is exceeded in the section C1. The number of times the opening degree of the APC valve 55 exceeds the first critical value Th will be counted and accumulated. At a time point t1 when the count value generated by the excess counter 124 exceeds the second critical value, the mass flow controller (MFC) 43 reduces the flow rate of the process gas from V ₀ to V ₁ .

Next, the degree of opening and closing of the APC valve 55 is monitored again in accordance with the procedure of steps S1 to S5 in FIG. 5, and based on the result, in the section C2, the degree of opening of the cumulative APC valve 55 exceeds the first critical value Th. The number of times. Further, at a time point t2 at which the count value generated by the excess counter 124 exceeds the second critical value, the mass flow controller (MFC) 43 reduces the flow rate of the process gas from V ₁ to V ₂ . Thereafter, in the case where the pressure rise continues, the same processing is repeatedly executed until the plasma etching process is completed.

As described above, in the pressure control method of the present embodiment and the plasma etching method using the method, the pressure rise in the processing container 1 can be offset by suppressing the flow rate of the processing gas, whereby the pressure increase in the processing container 1 can be alleviated.

Fig. 9 is a view showing experimental results of applying the pressure control method of the present embodiment to the actual plasma etching treatment in the plasma etching apparatus 100. In this experiment, a laminated film of Ti/Al/Ti was used as an etching target film, and Cl ₂ (chlorine) was used as a processing gas (etching gas). According to the procedure of the above steps S1 to S5, the increase in the degree of opening of the APC valve 55 is monitored, and the flow rate of the processing gas introduced into the processing container 1 is reduced in response to an increase in the degree of opening. Specifically, by repeating the procedures of steps S1 to S5, as shown in FIG. 9, the flow rate of the process gas was stepped down from 3,500 ml/min (sccm) to 1,700 ml/min (sccm). As a result, the pressure in the processing container 1 was stably changed approximately 10 mTorr (1.3 Pa). Therefore, the effectiveness of the pressure control method of the present embodiment can be confirmed from Fig. 9 .

As described above, according to the present embodiment, in the plasma etching apparatus 100 that performs pressure adjustment in the processing container 1 by the APC valve 55, the opening degree of the APC valve 55 is monitored, and the introduction is adjusted to the processing based on the result. The flow rate of the process gas in the vessel 1. For example, when the degree of opening is increased, the gas flow rate can be reduced, and the pressure rise in the processing container 1 can be offset by suppressing the flow rate of the processing gas, and the pressure rise in the processing container 1 can be alleviated. Further, the increase in the opening degree of the APC valve 55 is before the pressure in the processing container 1 rises, and therefore, the flow rate of the processing gas is changed in accordance with the pressure measurement result in the processing container 1, and it is more excellent in responsiveness. Therefore, according to the present invention, in the large-sized vacuum apparatus, the pressure control in the processing container 1 can be surely performed without increasing the number of the exhaust devices 57 and the APC valves 55 including the vacuum pump. Moreover, since excess radicals generated by the pressure increase in the processing container 1 can be suppressed, it is possible to prevent the pattern formation formed on the surface of the substrate S from collapsing.

[Second Embodiment]

Next, a plasma etching apparatus, a pressure control method, and a plasma etching method according to a second embodiment of the present invention will be described with reference to Figs. 10 and 11 . in In the present embodiment, the increase rate of the opening degree of the APC valve 55 within a predetermined time is obtained, and it is determined whether or not the gas flow rate is adjusted based on the increase rate. In the following description, the differences from the first embodiment will be mainly described, and the same configurations as those in the first embodiment will be omitted.

Fig. 10 is a functional block diagram showing the functional configuration of the device controller (EC) 81A of the plasma etching apparatus of the present embodiment. In the following description, the hardware configuration of the EC 81A is formed as shown in FIG. 3, and the reference numerals in FIG. 3 may be referred to. As shown in FIG. 10, the EC81A includes a process control unit 121, an opening degree monitoring unit 122, an opening degree calculation unit 126, and an input/output control unit 125. These are implemented by the CPU 111 using the RAM 112 as a work area and executing a program stored in the ROM 113 or the memory device 105.

The processing control unit 121, the opening/closing degree monitoring unit 122, and the input/output control unit 125 have the same functions as those of the first embodiment.

The opening degree calculation unit 126 refers to the opening degree of the APC valve 55 that is immediately acquired by the opening degree monitoring unit 122 (or the opening degree monitoring unit of the APC valve 55), and calculates the opening degree of the APC valve 55 within a predetermined elapsed time range. Increase rate. In other words, the opening degree calculation unit 126 refers to the opening degree monitoring unit 122 (or the opening degree monitoring unit of the APC valve 55) in accordance with any time interval stored in the memory device 105 as a part of the parameter or the processing program. The opening degree is obtained from the difference to determine the increase rate of the opening degree in the time interval.

The flow rate control unit 121a performs whether or not the increase rate of the opening degree calculated by the opening degree calculation unit 126 exceeds a predetermined threshold (third aspect) When the increase rate of the opening degree exceeds the third critical value, the control signal is sent to the mass flow controller (MFC) 43 via the MC 83 to reduce the flow rate of the processing gas by a predetermined amount. Thereby, the mass flow controller (MFC) 43 reduces the flow rate of the process gas by a predetermined amount. Here, the third threshold value means that the flow rate control unit 121a refers to one of the parameters or the processing program and stores it in advance in the memory device 105. Further, the amount of reduction in the processing gas is also stored in the memory device 105 in advance by the flow rate control unit 121a as a part of the parameter or the processing program.

The pressure control method of the present embodiment may include the procedures of steps S11 to S14 as shown in FIG. Fig. 11 shows a procedure for controlling the flow rate of the mass flow controller (MFC) 43 by monitoring the opening degree of the APC valve 55 until the flow rate of the mass flow controller (MFC) 43 is performed once.

First, in step S11, the EC 81 will acquire the opening degree of the APC valve 55. The opening degree acquisition of the APC valve 55 may be performed by the opening degree monitoring unit 122 of the EC81A via the MC 83, or may be transmitted to the EC 81A via the MC 83 by the opening degree monitoring function attached to the APC valve 55.

Next, in step S12, the degree of increase in the predetermined elapsed time range of the opening degree of the APC valve 55 acquired in step S11 is calculated by the opening degree calculation unit 126 of the EC 81A.

Next, in step S13, the flow rate control unit 121a determines whether or not the increase rate of the opening degree calculated by the opening degree calculation unit 126 exceeds the third threshold value. And, when the increase rate of the opening degree is determined to exceed the third critical value (Yes), in the next step S14, the flow rate control The portion 121a sends a control signal to the mass flow controller (MFC) 43 via the MC 83 to reduce the flow rate of the processing gas by a predetermined amount.

On the other hand, if it is determined in step S13 that the excess count value has not exceeded the third critical value (No), the process returns to step S11 again and the procedures of steps S11 to S13 are repeated. The procedure from step S11 to step S13 is repeated until the increase rate of the opening degree is judged to exceed the third critical value (Yes) or the plasma etching process is ended in step S13.

According to the procedures of the above steps S11 to S14, the pressure change in the processing container 1 can be suppressed. In the present embodiment, the increase rate of the opening degree in the predetermined time is used as the index, but the same control may be performed based on the difference in the degree of opening and closing in the predetermined time.

Other configurations and effects of the embodiment are the same as those of the first embodiment.

Hereinabove, the embodiments of the present invention have been described in detail for the purpose of illustration, but the invention is not limited to the embodiments described above. It will be apparent to those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the invention. For example, although the above embodiment is a parallel plate type plasma etching apparatus, the present invention is also applicable to, for example, an inductively coupled plasma device, a surface wave plasma device, an ECR (Electron Cyclotron Resonance) plasma device, and a spiral wave electric device. Other types of plasma etching devices such as slurry devices. Moreover, if it is a vacuum apparatus which has a pressure adjustment in a chamber provided with an APC valve, it is not limited to a dry etching apparatus, and is equally applicable to a film forming apparatus, an ashing apparatus, etc..

Moreover, the present invention is not limited to the case where the substrate for FPD is used as the object to be processed, and may be applied to, for example, a semiconductor wafer or a substrate for a solar cell as the object to be processed.

Further, in the above-described embodiment, the case where the opening degree of the APC valve 55 and the pressure in the processing container 1 are increased to reduce the flow rate of the processing gas is exemplified, but the present invention is also applicable to the opening of the APC valve 55. The degree of mixing and the pressure in the processing container 1 are lowered to increase the flow rate of the processing gas.

Claims (16)

A vacuum apparatus comprising: a processing container that can accommodate a target object and maintains a vacuum inside; a gas supply source supplies a processing gas to the processing chamber via a gas supply path; and a flow rate adjusting device is provided in the gas supply path, and Adjusting a supply flow rate of the processing gas; a pressure detecting device detecting a pressure in the processing container; and an exhaust device connected to the processing container via an exhaust path; the automatic pressure control valve being disposed in the exhaust path, and The pressure value detected by the pressure detecting device automatically adjusts the opening degree; the opening degree monitoring unit monitors the opening degree of the automatic pressure control valve; and the flow rate control unit adjusts the monitoring result according to the opening degree monitoring unit The flow rate control unit compares the opening degree of the automatic pressure control valve with a predetermined threshold value, and based on the result, repeats the process of controlling the flow rate adjusting device to reduce the amount set in advance. The amount of supply of the aforementioned processing gas is reduced. The vacuum device according to claim 1, wherein the flow rate control unit controls the flow rate adjusting device to reduce a supply flow rate of the processing gas when the opening degree of the automatic pressure control valve exceeds a predetermined threshold. Such as the vacuum device of claim 1 of the patent scope, wherein Further, the counter unit is configured to count the number of times the opening degree of the automatic pressure control valve exceeds a first threshold value, and the flow rate control unit controls the flow rate adjusting device when the count value exceeds a second threshold value The supply flow rate of the process gas is reduced. The vacuum apparatus according to the first aspect of the invention, further comprising: an opening degree calculation unit that calculates an increase rate of the opening degree of the automatic pressure control valve within a predetermined elapsed time period, wherein the flow rate control unit is When the increase rate of the opening degree exceeds the third critical value, the flow rate adjusting device is controlled to reduce the supply flow rate of the processing gas. The vacuum device according to any one of claims 1 to 4, wherein the vacuum device is an etching device that etches a target object. A vacuum apparatus according to claim 5, wherein the substrate for processing the system FPD. A pressure control method for a vacuum device for controlling pressure of a pressure in the processing container in a vacuum device having a processing container, a gas supply source, a flow rate adjusting device, a pressure detecting device, an exhaust device, and an automatic pressure control valve In the processing container, the object to be processed is placed in a vacuum state, and the gas supply source supplies a processing gas to the processing chamber via a gas supply path, and the flow rate adjusting device is disposed in the gas supply path. And adjusting the supply flow rate of the processing gas, the pressure detecting device detecting the pressure in the processing container The exhaust device is connected to the processing container via an exhaust path, and the automatic pressure control valve is disposed in the exhaust path, and automatically adjusts the opening degree according to the pressure value detected by the pressure detecting device. The pressure control method of the vacuum device is characterized in that the opening degree of the automatic pressure control valve is monitored, the opening degree is compared with a predetermined threshold value, and according to the result, the process of controlling the flow rate adjusting device is repeatedly performed to The amount of reduction in advance is set to reduce the supply flow rate of the processing gas. The pressure control method of the vacuum apparatus according to claim 7, wherein when the opening degree of the automatic pressure control valve exceeds a predetermined threshold value, the supply flow rate of the processing gas is controlled to be reduced. The pressure control method of the vacuum apparatus of claim 7, wherein the processing is performed by counting the number of times the opening degree of the automatic pressure control valve exceeds the first critical value, and when the count value exceeds the second critical value The way in which the supply flow of gas is reduced is controlled. The pressure control method of the vacuum apparatus of claim 7, wherein the processing gas is caused by a rate of increase of the opening degree of the automatic pressure control valve exceeding a third critical value within a predetermined elapsed time range The way the supply flow is reduced is controlled. The pressure control method for a vacuum device according to any one of claims 7 to 10, wherein The vacuum device is an etching device that etches a target object. The pressure control method of a vacuum apparatus according to claim 11, wherein the substrate for the FPD to be processed is used. An etching method is an etching method for etching an object to be processed using an etching apparatus, the etching apparatus comprising: a processing container capable of accommodating the object to be processed and maintaining a vacuum inside; and a gas supply source via a gas supply path pair a processing gas is supplied into the processing chamber; a flow rate adjusting device is provided in the gas supply path to adjust a supply flow rate of the processing gas; a pressure detecting device detects a pressure in the processing container; and the exhaust device is connected via an exhaust path And the automatic pressure control valve is disposed in the exhaust path, and automatically adjusts the opening degree according to the pressure value detected by the pressure detecting device; the etching method is characterized by the automatic pressure control valve The opening degree is monitored, and the opening degree is compared with a predetermined threshold value. Based on the result, the process of controlling the flow rate adjusting device is repeatedly performed to reduce the supply flow rate of the processing gas by a predetermined amount of reduction. The etching method of claim 13, wherein the supply flow rate of the processing gas is decreased when the opening degree of the automatic pressure control valve exceeds a predetermined threshold. For example, in the etching method of claim 13, wherein The number of times the opening degree of the automatic pressure control valve exceeds the first critical value is counted, and when the count value exceeds the second critical value, the supply flow rate of the processing gas is decreased. The etching method of claim 13, wherein the supply flow rate of the processing gas is decreased when the increase rate of the opening degree of the automatic pressure control valve exceeds the third critical value within a predetermined elapsed time range Way to control.