WO2002082521A1

WO2002082521A1 - Processing method and processor

Info

Publication number: WO2002082521A1
Application number: PCT/JP2002/002539
Authority: WO
Inventors: Eiji Takahashi; Kenetsu Mizusawa; Jun Hirose
Original assignee: Tokyo Electron Limited
Priority date: 2001-03-30
Filing date: 2002-03-18
Publication date: 2002-10-17
Also published as: JP2002296096A

Abstract

When process gas is supplied into a chamber (30) at a specified flow rate and a wafer W is processed in the chamber (30), flow rate of process gas is self-diagnosed by a self-diagnosis circuit in a flow rate controller (11) every time when the wafer W is processed with the process gas utilizing the time for replac a processed wafer W with a wafer W to be processed effectively. Since the flow rate controller (11) can be self-diagnosed on a wafer basis without interrupting the processing operation of the wafer W, throughput of processing operation is not lowered.

Description

Description Processing method and processing equipmentTechnical field

The present invention relates to a processing method and a processing apparatus, and more specifically, every time an object to be processed such as a wafer is processed one by one using a process gas, the flow rate of the process gas is adjusted in parallel with the processing of the object to be processed. The present invention relates to a processing method and a processing device capable of performing a diagnosis.

Background art

2. Description of the Related Art In a semiconductor manufacturing process, there is a process of performing various processes such as etching and film formation on an object to be processed such as a wafer using various process gases. The processing apparatus used in this process includes, for example, a gas supply source for individually supplying a plurality of types of process gases, a processing chamber connected to these gas supply sources via a gas supply line, and a gas in the processing chamber. And an exhaust device connected via an exhaust line for exhausting air. A flow control device such as a mass flow controller for controlling the flow rate of the process gas is provided in the gas supply line, and the process gas is controlled at a predetermined flow rate through these flow control devices and supplied into the processing chamber. ing. In the processing chamber, an object to be processed is subjected to processes such as an etching process and a film forming process using plural kinds of process gases whose flow rates are controlled.

On the other hand, the control of the flow rate of process gas in processes such as etching and film formation has become more important than ever before as integrated circuits become ultrafine and thinner. It is necessary to control the process gas with high precision. In the case of conventional processing equipment, since the flow rate of the process gas is controlled by the flow rate control device, it is assumed that the process gas is always supplied at the set flow rate. Even during processing of the object to be processed due to disturbances even in the equipment, there is no guarantee that the gas flow rate is always controlled at the set flow rate, and the control flow rate of the process gas is checked as necessary. Diagnosis of loose flow is required.

However, when diagnosing the flow rate of the flow control device, a process dedicated to the flow rate diagnosis must be provided when the processing of the object to be processed is interrupted, for example, when the lot is switched or when the device is started up. And there is a problem that the throughput decreases accordingly. Disclosure of the invention

An object of the present invention is to provide a processing method and a processing apparatus capable of reliably performing a self-diagnosis of a flow rate without interrupting processing of a target object and performing processing of a target object without reducing throughput. _(In order to solve the above-described problems, according to the present invention, a method of supplying a process gas at a predetermined flow rate into a processing chamber and processing a target object in the processing chamber, Diagnosing the flow rate of the process gas every time the process target is processed with the process gas.

Further, according to the present invention, in a method of supplying a process gas having a flow rate controlled through a flow rate control device to a processing chamber through a gas supply line and processing an object to be processed in the processing chamber, A flow control device capable of self-diagnosis is provided as a device, and a branch line is provided in the gas supply line, and the gas supply line is switched to the branch line each time the process target is processed with the process gas. The flow control device performs self-diagnosis of the flow rate of the process gas. Further, according to the present invention, in a method for supplying a process gas having a flow rate controlled through a flow rate control device to a processing chamber via a gas supply line, and processing an object to be processed in the processing chamber, the gas supply line A branch line is provided and a flow detector is provided in the branch line. Each time the object to be processed is processed with the process gas, the gas supply line is switched to the branch line, and the process gas is switched in the flow detector. It is characterized by diagnosing the flow rate.

Further, according to the present invention, in a processing apparatus for supplying a process gas having a flow rate controlled through a flow rate control device to a processing chamber through a gas supply line and processing an object to be processed in the processing chamber, A flow control device capable of self-diagnosis is provided as a device, a first valve is provided in the gas supply line, a branch line is provided from the gas supply line, and a second valve is provided in the branch line. Each time the process object is treated with the process gas, the first valve is closed and the second valve is opened to switch from the gas supply line to the branch line, and the process gas is supplied to the branch line. The flow rate control device performs a self-diagnosis of the flow rate of the process gas.

Further, according to the present invention, in a processing apparatus for supplying a process gas whose flow rate is controlled via a flow rate control device to a processing chamber via a gas supply line, and for processing an object to be processed in the processing chamber, A first valve is provided on the line and a branch line is provided for branching from the gas supply line.A second valve and a flow detector are provided on the branch line, and each time the object is processed with the process gas. Close the first valve and open the second valve to switch from the gas supply line to the branch line, flow the process gas through the branch line, and diagnose the flow rate of the process gas with the flow rate detector It is characterized by doing. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram showing an embodiment of the processing apparatus of the present invention.

FIG. 2 is a block diagram showing the configuration of the flow control device shown in FIG. FIG. 3 is a view corresponding to FIG. 1 showing another embodiment of the processing apparatus of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described based on the embodiment shown in FIGS.

As shown in FIG. 1, for example, the processing apparatus of the present embodiment includes a gas box 10 for controlling the flow rates of a plurality of types of process gases, and a chamber connected to the gas box 10 via a gas supply line 20. A vacuum exhaust device 40 for evacuating the chamber 30; and an exhaust gas line 50 for exhausting the gas in the chamber 130 via the vacuum exhaust device 40. A plurality of process gases are controlled at a predetermined flow rate through the gas box 10 and supplied into the chamber 130, and the inside of the chamber 30 is evacuated to a predetermined vacuum level through the vacuum exhaust device 40. A predetermined process (for example, etching) is performed on an object to be processed (for example, wafer W) while holding the substrate.

In the gas box 10, for example, six flow control devices (FCS) 11 having the same configuration are provided, and a plurality of flow control devices 11 required for a predetermined etching process via these flow control devices 11. Each kind of process gas is controlled to a predetermined flow rate. These flow rate control devices 11 are configured to be able to self-diagnose the flow rate of each of them as described later, Each is set up individually. The first branch line 2 1 to 2 5 is the remaining second branch line 2 6 It branches off from the gas supply line 20 on the more upstream side. A first valve 12 and a second pulp 13 are provided on the upstream and downstream sides of the flow control device 11, respectively, and each of them is branched via the first and second valves 12 and 13. Open and close lines 21-26. These self-diagnosable flow control devices 11 will be described later. Further, a third branch line 27 branches from the second branch line 26, and a third valve 14 is provided in the third branch line 27. The second branch line 26 supplies nitrogen gas when the amount of nitrogen gas needs to be adjusted during the process or when the flow rate of nitrogen gas needs to be adjusted appropriately (for example, when transferring a wafer). The third branch line 27 is used as a pipe for supplying nitrogen gas when the flow rate adjustment is unnecessary, for example, when the atmosphere is opened to the atmosphere. Further, a fourth valve 60 is provided between the junction of the first branch lines 21 to 25 and the junction of the second branch line 26, and nitrogen gas as a process gas is supplied to the fourth valve 6 Merges with other process gas downstream of 0.

The gas supply line 20 has a fourth branch line 28 branched between the junction of the first branch lines 21 to 25 and the fourth valve 60. The downstream end of the fourth branch line 28 is connected to the exhaust gas line 50 on the downstream side of the vacuum exhaust device 40. A fifth valve 70 is provided in the fourth branch line 28, and when performing self-diagnosis of the control flow rate of the flow control device 11, the fifth valve 70 is opened, and the process gas is supplied to the gas exhaust line 50. It is designed to discharge. Further, a sixth valve 80 is provided downstream of the branch point of the second branch line 26 of the gas supply line 20, and this valve 80 is connected to the flow control device 11 similarly to the fifth valve 70. Used for self-diagnosis of control flow rate.

As shown in FIG. 1, a lower electrode 31 and an upper electrode 32 are provided in the chamber 30 as conventionally known, and these two electrodes 31 and 3 2 are connected to each other. They are opposed to each other via a gap. The lower electrode 31 is connected to a high-frequency power source 34 via a matching device 33, and the upper electrode 32 is grounded. Further, the upper electrode 32 is formed in a hollow shape, and a large number of holes are formed on the lower surface thereof so as to be evenly dispersed. Therefore, when a plurality of kinds of process gases are controlled to a predetermined flow rate and supplied into the upper electrode 32 through the flow rate control device 11 in the gas box ί 0, the plurality of kinds of process gases are stored in the upper electrode 32. After being uniformly mixed, it is supplied into the chamber 30 through the hole on the lower surface and is evenly diffused. When high-frequency power is applied to the lower electrode 31 in this state, the wafer W on the lower electrode 31 can be subjected to predetermined etching.

Although not shown, the chamber 30 is connected to the transfer chamber via a gate valve as is conventionally known, and the wafer W is loaded and unloaded into the chamber 30 via an arm in the transfer chamber. I do. In the chamber 30, the transfer of the wafer W carried by the arm is performed via the lifting pins built in the lower electrode 31. An electrostatic chuck is provided on the lower electrode 31, and a wafer W is electrostatically attracted on the lower electrode 31 by applying a high DC voltage to the electrostatic chuck. Further, the lower electrode 31 has a back gas supply means and a temperature control means, and supplies a back gas having excellent heat transfer properties such as He gas between the wafer W and the static chuck via the back gas supply means. At the same time, the temperature of the wafer W on the lower electrode 31 is adjusted to a predetermined temperature via the temperature adjusting means.

Next, the flow control device 11 will be described with reference to FIG. As the flow control device 11, for example, a pressure-type flow control device proposed in Japanese Patent Application Laid-Open No. 11-222603 can be used. The flow rate control device 11 includes a self-diagnosis circuit for the control flow rate as described later. This self-diagnosis circuit is a diversion of the clogging detection circuit described in the above publication. Therefore, since the principle of the flow control device 11 having the self-diagnosis circuit is based on the pressure type flow control device described in the above publication, the flow control device 11 will be described below. An outline will be described.

As shown in Fig. 2, the flow control device 11 is composed of a control valve 1 11, a pressure detector 1 12, a temperature detector 1 13, an orifice 1 14, an arithmetic control unit (CPU) 1 15, and an amplifier. It has 1 16, 1 17, A / D converters 1 18, 1 19, and a drive section 120, and functions assuming a pressure ratio P 1 / P 2 ≥ 2 around the orifice 1 14. That is, the gas pressure P1 and the gas temperature T1 of the branch line 21 are detected via the pressure detector 112 and the temperature detector 113, and these detection signals are amplified via the amplifiers 116, 117. After amplification, the signal is converted into a digital signal via the AZD converters 118 and 119 and output to the arithmetic control unit 115. The arithmetic control unit 115 corrects the gas flow rate of the branch line 21 based on the gas pressure and gas temperature detection signals, and then sets the set flow rate Qs from the flow rate setting circuit 121 and the temperature corrected Comparing the calculated flow rate Qc, outputs the calculation control signal SI based on the difference between the set flow rate Qs and the calculated flow rate Qc to the drive unit 120 via the amplifier 122, and adjusts the opening of the control valve 111. To maintain the set flow rate Qs.

The flow control device 11 has a self-diagnosis circuit 123 under the control of the arithmetic control unit 115. The self-diagnosis circuit 123 has a test circuit 123A and an amplifier 123B. The test circuit 1 2 3 A is a test signal generation circuit that outputs the set flow rate Qs (t) (= Qso + AQ _S ) consisting of the steady set flow rate Qso and the test signal ΔQs, and self-tests with the test signal AQs. Make a diagnosis. This signal controls the drive unit 120 via the amplifier 123B, and controls the opening and closing of the control valve 111. Also, the pressure P (t) on the upstream side of the orifice 1 14 of the second branch line 21 to 26 is also the sum of the steady pressure Plo and the fluctuating pressure Δ 、, that is, P (t) = ΡΙΟ + Δ ΡΙ Given as The steady pressure Plo corresponds to the steady set flow rate Qso, and the fluctuating pressure ΔΡΙ corresponds to the verification signal AQs. Therefore, a predetermined reference value is set for the test signal AQs, Based on this reference value, it can be diagnosed whether the control flow rate fluctuation is an allowable control flow rate within the reference value. Then, when the value deviates from the allowable range, a notification is made, for example, via an alarm circuit 125. Based on the notification from the alarm circuit 125, it is possible to know which process gas has deviated from the permissible value, and it is also possible to investigate the cause. When the self-diagnosis circuit 1 2 3 functions, the external circuit 1 2 4 outputs a self-diagnosis signal to the arithmetic control unit 1 1 5, and the arithmetic control unit 1 1 The output of the control signal to 2 is interrupted, and the flow control by the flow controller 11 is temporarily interrupted. Since the self-diagnosis of the flow rate is completed in a short time, the flow rate control during this time is guaranteed by the steady set flow rate Qso of the verification circuit 122 A.

Next, a method for treating an object to be treated using the flow rate control device 11 will be described. First, the fourth valve 60 of the gas supply line 20 is closed, the valve 14 of the second branch line 27 and the sixth valve 80 of the gas supply line 20 are opened, and nitrogen gas is supplied to the chamber 13. After purging the residual gas in 0, the valve 14 of the second branch line 27 and the sixth valve 80 of the gas supply line 20 are closed, the gate valve of the chamber 130 is opened, and the arm in the transfer chamber is opened. The wafer W is conveyed into the chamber 30 via the, and the wafer W is transferred to and from the lift pins of the lower electrode 31. Subsequently, the elevating pins retract into the lower electrode 31 and the electrostatic chuck operates to fix the wafer W on the lower electrode 31. During this time, the arm retreats from the chamber 130 into the transfer chamber, closes the gate valve, and finishes loading the wafer W.

After that, a back gas such as He gas is supplied to the back surface of the wafer W, and the pressure control in the chamber 130 is started. At the time of pressure control, the first and second valves 12 and 13 of the gas box 10 are opened, and the fourth and sixth valves 60 and 80 of the gas supply line 20 are opened, and the fourth branch line 28 is opened. 5 valve A predetermined process gas whose flow rate is controlled via the flow control device 11 is supplied into the chamber 130 via the gas supply line 20 with the 70 closed, and the lower electrode is supplied from the high frequency power supply 34. 3 Apply high frequency power to 1 to start the etching process. During this time, the wafer W is controlled to a predetermined temperature by the action of the back gas. After a lapse of a predetermined time, the application of the high-frequency power is stopped to end the etching.

Next, after temporarily stopping the pressure control and closing the fourth valve 60 to stop the supply of the process gas into the chamber 30, the third valve 14 and the fourth valve in the third branch line 27 are stopped. The fifth valve 70 of the branch line 28 is opened, and the process gas is exhausted from the fourth branch line 28 through the exhaust gas line 50. Also, the valve 13 of the second branch line 26 is opened, and nitrogen gas is supplied as a purge gas into the chamber 130 through the gas supply line 20 so that the nitrogen gas in the chamber 130 is purged. The pressure is kept constant and the operation of the electrostatic chuck is stopped to make the wafer W replaceable. Subsequently, the gate valve is opened, and the wafer W is transferred at the lower electrode 31 via the lifting pins and the arms, and is carried out from the chamber 130 to the transfer chamber. Next, the next unprocessed wafer W is loaded into the chamber 130 as described above. Thus, in the present embodiment, the process gas flow path is changed from the gas supply line 20 to the fourth branch line 2 while the processed wafer W is replaced with the unprocessed next wafer W after the processing of the wafer W. Switch to 8 and perform self-diagnosis automatically based on the self-diagnosis program registered in advance. That is, the process gas is exhausted from the fourth branch line 28 to the exhaust gas line 50 between the time when the residual gas in the chamber 30 is purged with nitrogen gas and the time when the unprocessed wafer W is loaded. The self-diagnosis circuit 123 performs self-diagnosis of the control flow rate of the flow control device 111 using the self-diagnosis circuit 123. For this purpose, a self-diagnosis signal is output from the external circuit 124 to the arithmetic control unit 115. The arithmetic and control unit 1 1 5 triggers this signal. The output of the control signal to the amplifiers 122 as the gar signal is interrupted, and the flow control by the flow control device 11 is temporarily interrupted. However, since the self-diagnosis of the flow rate is completed in a short time, the flow rate control during this time is guaranteed by the steady set flow rate Qso of the test circuit 122 A. If the control flow rate deviates from the allowable range in the self-diagnosis, it can be known through the alarm circuit 125. Since the self-diagnosis is performed during the replacement of the wafer W, the replacement process of the wafer W can be effectively used as the self-diagnosis process.

As described above, the processing apparatus of the present embodiment supplies the process gas whose flow rate has been controlled by the flow rate control device 11 into the chamber 130 via the gas supply line 20, In the processing apparatus for processing the wafer W, a self-diagnosis circuit 123 is provided in the flow control device 111 to enable self-diagnosis, and a valve 60 is provided in the gas supply line 20 so that the gas supply can be performed. A fourth branch line 28 branching from the line 20 is provided, and a valve 70 is provided in the branch line 28. The valve 60 is closed and the valve 7 is closed each time the wafer W is processed with the process gas. 0 is opened, the gas supply line 20 is switched to the fourth branch line 28, and the process gas flows through the fourth branch line 28.The flow rate of the process gas is controlled by the self-diagnosis circuit 1 2 3 of the flow controller 11. Configured to self-diagnose .

Each time the wafer W is processed with the process gas, the process gas flow is effectively utilized by replacing the processed wafer W with the unprocessed wafer W, and the flow rate of the process gas is determined using the self-diagnosis circuit of the flow control device 11. Since the self-diagnosis is performed by performing the self-diagnosis, the self-diagnosis of the flow rate control device 11 can be performed without interrupting the processing of the wafer W and in units of single wafers, and the throughput of etching is not reduced.

FIG. 3 is a configuration diagram showing a processing apparatus according to another embodiment of the present invention. In the processing device of the present embodiment, the flow control device 11 does not have a self-diagnosis function, The configuration is the same as that of the processing device shown in Fig. 1 except that a flow rate detector for flow rate diagnosis is separately provided. Therefore, the same or corresponding parts as those of the processing apparatus shown in FIG. 1 are denoted by the same reference numerals, and only the features of the present embodiment will be described.

In the present embodiment, a flow detector 90 is provided downstream of the fifth valve 70 of the fourth branch line 28, and the control flow of each flow controller 11 is checked by the flow detector 90. ing. In FIG. 3, reference numeral 91 denotes a valve used when discharging the gas in the container of the flow detector 90.

The flow rate detector 90 includes, for example, a small-capacity container having a known capacity, a pressure gauge for detecting the pressure in the container, a thermometer for detecting a gas temperature in the container, And a timer for measuring a time required to fill the gas to a predetermined pressure. Then, the pressure rise (Δ Ρ) generated within a certain time (Δ ガス) when the gas is filled in the container having the constant volume V is measured, and the gas flow rate Q is obtained based on the following equation. Of course, when calculating the gas flow rate, the gas flow rate is corrected at the temperature at that time. When the control flow rate of the flow control device 11 is checked by the flow rate detector 90, it is performed for each process gas. Q s c cm = [V · △ ρ / Δ t] · [Temperature correction coefficient]

Also in the processing apparatus of the present embodiment, the control flow rate of the flow control device 11 can be checked by the flow rate detector 90 by operating the processing apparatus in the same procedure as in the above embodiment. Therefore, in the present embodiment, the same operation and effect as those in the above-described embodiment can be obtained.

In the above embodiment, the case where the self-diagnosis is performed for each processing of the wafer W has been described. However, by using the processing apparatus of the present invention, the timing of the self-diagnosis is independent of the processing method of the present invention. The self-diagnosis can be performed by appropriately selecting or selecting an appropriate gas from a plurality of types of gases. For example, when changing the process gas ratio, the process used in the following recipe: The self-diagnosis of the process gas can be performed immediately before, or the process gas used in the immediately preceding recipe can be self-diagnosed.

When a plurality of types of process gases are used, the self-diagnosis may be selectively performed only on the process gas that greatly affects the process characteristics. In the case of the same recipe, a self-diagnosis may be performed for each recipe, or a self-diagnosis may be performed for a plurality of types of gases at the first time when the recipe is changed, and then a self-diagnosis may be performed for a plurality of types of gases in order. .

In the present invention, the timing for performing the self-diagnosis of the control flow rate is not limited to the above embodiments. In short, the present invention only needs to be a processing method for performing a flow rate diagnosis by effectively utilizing the time for replacing the wafer W each time the wafer W is processed. In each of the above embodiments, the wafer etching process has been described as an example. However, the object to be processed can be widely applied to other substrates such as a liquid crystal LCD substrate other than the wafer. It goes without saying that the present invention can be widely applied to processes such as film formation.

As described above, according to the present invention, the self-diagnosis of the flow rate can be reliably performed without interrupting the processing of the processing target, and the processing of the processing target can be performed without lowering the throughput. Industrial applicability

The processing method and the processing apparatus according to the present invention can be used in a semiconductor manufacturing industry or the like that manufactures semiconductor devices. Therefore, it has industrial applicability.

Claims

The scope of the claims

1. In a method for supplying a process gas at a predetermined flow rate into a processing chamber and processing an object to be processed in the processing chamber,

A processing method characterized by diagnosing the flow rate of the process gas every time the process target is processed with the process gas.

2. In the method of processing a target object in the processing chamber, supplying the process gas whose flow rate is controlled through the flow rate control device through the gas supply line into the processing chamber.

A self-diagnostic flow control device is provided as the gas flow control device, a branch line is provided in the gas supply line, and the gas supply line is connected to the branch line every time the process target is processed with the process gas. A processing method characterized by performing a self-diagnosis of the flow rate of the process gas in the flow rate control device by switching.

3. In the method of processing a target object in the processing chamber, supplying the process gas having the flow rate controlled through the flow rate control device through the gas supply line into the processing chamber.

A branch line is provided in the gas supply line, and a flow rate detector is provided in the branch line. The gas supply line is switched to the branch line each time the process target is processed with the process gas, and the flow rate is detected. Diagnosing the flow rate of the process gas in a vessel.

4. In a processing apparatus for supplying a process gas having a flow rate controlled through a flow rate control device to a processing chamber through a gas supply line and processing an object to be processed in the processing chamber,

A self-diagnostic flow control device is provided as the flow control device, and a first valve is provided in the gas supply line. A second valve is provided in the branch line, and the first valve is closed and the second valve is opened each time the process target is processed with the process gas. A processing apparatus characterized by switching from a gas supply line to the branch line, flowing the process gas through the branch line, and self-diagnosing the flow rate of the process gas in the flow control device.

5. In a processing apparatus for supplying a process gas whose flow rate is controlled through a flow rate control device to a processing chamber through a gas supply line and processing an object to be processed in the processing chamber,

A first valve is provided in the gas supply line and a branch line is provided for branching from the gas supply line.A second valve and a flow detector are provided in the branch line, and the object to be processed is treated with the process gas. Each time the first valve is closed, the second valve is opened and the gas supply line is switched to the branch line to flow the process gas through the branch line. A processing device characterized by diagnosing the flow rate.