JP2010258089A - Method of operating vacuum processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of operating a vacuum processing apparatus that can reduce foreign matters adhering to a sample and that can improve the throughput of the apparatus as a whole. <P>SOLUTION: A variable valve is released at specified opening to reduce pressure in a vacuum processing chamber; and when the reduction of pressure is completed, the output value of a pressure sensor is corrected at zero point for resetting. Then a sample transfer gas is supplied by a gas supply mechanism; and a gate valve is released, while the gas is being supplied so as to carry in the sample; after the sample is carried in, a gas for processing a sample is supplied, while the gate valve is closed and the sample transfer gas is being supplied; the supply of the sample transfer gas is stopped, and plasma treatment is applied; and after the plasma treatment is completed, the sample transfer gas is supplied, prior to the stoppage of supply of the gas for processing a sample. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an operation method of a vacuum processing apparatus, and more particularly to an operation method capable of suppressing adhesion of foreign matter on a sample.

  In recent semiconductor device manufacturing processes, it is important to reduce foreign substances that are a cause of a decrease in manufacturing yield. In addition, with the miniaturization of elements accompanying higher integration of devices, the particle size of foreign matter that causes a decrease in yield is also reduced, and the demand for foreign matter reduction is increasing.

  As a technique for reducing foreign matter adhering to a sample in a plasma processing apparatus, for example, in Patent Document 1, a vacuum processing apparatus is configured with a processing chamber, a transfer chamber, a passage connecting them, and a gate valve for opening and closing the passage. In a vacuum processing apparatus for transporting and processing a sample, when a sample to be processed is transported between the processing chamber and the transport chamber, the pressure adjusting variable valve located below the vacuum container is set to a predetermined opening degree in the vacuum container. After that, the gas flow is formed by flowing Ar gas from the introduction hole into the vacuum vessel without changing the opening of the pressure adjusting variable valve, and in that state, the gate valve is opened to transport the sample. It is shown that the foreign matter adhering to the sample can be reduced and the yield of the sample processing can be improved by closing the gate valve after the sample transport and then stopping the introduction of Ar gas.

  Further, as a technique for reducing the amount of foreign matter adhering to a sample, Patent Document 2 discloses that the supply of a transfer gas supplied into the processing chamber overlaps with the supply of the processing gas when the sample is transferred between the transfer chamber and the processing chamber. It shows how to continue until you wrap.

  Further, in Patent Document 3, in order to suppress the adhesion of foreign matter to a sample, a vacuum transfer chamber is provided when a sample is transferred between a vacuum transfer chamber and a processing chamber connected to the vacuum processing chamber via a gate valve. It is shown that the sample transfer gas is supplied to the processing chamber and the switching timing of the sample transfer gas and the processing gas in the processing chamber before or after transfer of the sample is overlapped (wrapped).

JP 2008-172044 A JP 2006-216710 A Japanese Patent Application No. 2008-303807

  The technique disclosed in Patent Document 1 is not a technique that sufficiently considers foreign matter reduction and throughput improvement. That is, after the sample is loaded, the gate valve is closed, and then the introduction of Ar gas, which is the sample transport gas, is stopped, the processing chamber is once depressurized, and then the etching gas for processing is supplied.

  FIG. 6 is a sequence diagram showing this processing. In the example of FIG. 6, before the sample is carried into the vacuum processing chamber 102, the inside of the vacuum processing chamber 102 is decompressed, and Ar gas that is a sample transporting gas is 200 ml / min without changing the opening of the variable valve 121. Supplying at the above flow rate (time point a1 in FIG. 6), the gate valve 107 is opened in this state, and the sample is carried into the vacuum processing chamber 102 (time point c1 in FIG. 6). Thereafter, the gate valve 107 is closed (time point b2 in FIG. 6), the supply of Ar gas is stopped (time point a2 in FIG. 6), the inside of the vacuum processing chamber 102 is decompressed again, and an etching process gas for the etching process is supplied. Supplying (time point d1 in FIG. 6).

  In the case of this sequence, an idle time occurs between the stop of the Ar gas that is the sample transport gas and the supply of the etching process gas. This idle time is a period during which there is no gas flow in the processing chamber before the etching starts. Then, after that, the etching process gas is supplied, and it is considered that the foreign matter adhering to the processing chamber at this time floats and adheres to the sample. Note that the period from the stop of the sample transport gas (Ar gas) to the supply of the etching process gas is a period of high vacuum evacuation (a period during which the zero point correction of the pressure sensor can be performed) (note that each time point in FIG. 6 is represented). The reference numerals are the same as those in FIG.

  As described above, there is a period in which the gas flow in the processing chamber disappears due to the stop of the Ar gas supply until the start of etching. After that, when the etching processing gas is supplied, the foreign matter attached to the processing chamber floats. In addition to adhering to the sample, it takes time to stop the supply of Ar gas and then supply the etching process gas to control the inside of the processing chamber to a predetermined pressure, which reduces the throughput of the entire apparatus.

  Patent Document 2 shows that the flow of the carrier gas is continued until the processing gas is supplied in order to reduce foreign matter. However, the zero point correction of the pressure sensor or the conveyance sequence after the sample processing is not described, and no consideration is given to the practical use in terms of sequence.

  Further, in Patent Document 3, in order to suppress the adhesion of foreign matter to a sample, a vacuum transfer chamber is provided when a sample is transferred between a vacuum transfer chamber and a processing chamber connected to the vacuum processing chamber via a gate valve. It is shown that the sample transfer gas is supplied to the processing chamber and the switching timing of the sample transfer gas and the processing gas in the processing chamber before or after transfer of the sample is overlapped (wrapped). However, no consideration is given to improving the throughput.

  The present invention has been made in view of these problems, and it is an object of the present invention to provide a method of operating a vacuum processing apparatus capable of reducing foreign matter adhering to a sample and improving the throughput of the entire apparatus.

  In order to solve the above problems, the present invention employs the following means.

  A vacuum processing chamber having a gas supply mechanism for supplying a gas for sample processing and a gas for transporting a sample; plasma generating means for generating plasma by supplying high-frequency energy into the vacuum volume processing chamber; A vacuum transfer chamber connected to the lock chamber and having the other end connected to the vacuum processing chamber via a gate valve; exhaust means for exhausting gas in the vacuum transfer chamber; and gas in the vacuum processing chamber via a variable valve An exhaust means for exhausting and a pressure sensor for measuring the pressure in the vacuum processing chamber are provided, and the sample in the cassette is carried into the vacuum processing chamber via the lock chamber and the vacuum transfer chamber, and is vacuumed in the vacuum processing chamber. In the operation method of the vacuum processing apparatus for carrying out the processed sample after being processed through the vacuum transfer chamber and the lock chamber, the variable valve is released to a predetermined opening to reduce the vacuum processing chamber. When the decompression is completed, zero point correction is performed to reset the output value of the pressure sensor. After that, the sample transport gas is supplied through the gas supply mechanism, and the gate valve is released in the supplied state. Sample is loaded, sample processing gas is supplied with the gate valve closed after sample loading is completed and sample transport gas is continuously supplied, and then the sample transport gas supply is stopped. Then, plasma processing is performed, and after completion of the plasma processing, sample transport gas is supplied prior to stopping supply of the sample processing gas.

  Since the present invention has the above-described configuration, it is possible to reduce foreign substances adhering to the sample and improve the throughput of the entire apparatus.

It is a figure explaining a plasma etching apparatus. It is a figure which shows the modification of a plasma etching apparatus. It is a figure explaining the operating method of a plasma etching apparatus. It is a figure explaining the operating method of a plasma etching apparatus. It is a figure explaining the operating method of a plasma etching apparatus. It is a figure explaining the conventional operating method of a plasma etching apparatus.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating a vacuum processing apparatus according to an embodiment of the present invention, and in this example, a plasma etching apparatus.

  The plasma etching apparatus includes a vacuum transfer chamber 101 into which a sample is transferred from a lock chamber (not shown), and a vacuum processing chamber 102 connected to the vacuum transfer chamber 101 via a gate valve 107. An inert gas introduction path 118 is connected to the lower portion of the vacuum transfer chamber 101 in order to introduce an inert gas that is a sample transfer gas. The inert introduction path 118 is in communication with the inert gas source 116 and includes a mass flow controller 117 and an introduction valve 119 that adjust the flow rate of the inert gas. In addition, a turbo molecular pump 120 for adjusting the pressure in the vacuum transfer chamber 101 to a desired pressure is provided below the vacuum transfer chamber 101.

  A sample stage 108 is provided at the lower part of the vacuum processing chamber 102, and a plasma generation unit is formed at the upper part facing the sample stage 108. A lid member 106 constituting the vacuum processing chamber 102 is provided above the plasma generation unit, and an antenna 105 is disposed outside the vacuum processing chamber 102 via the lid member 106. The antenna 105 is connected to a high-frequency power source 103 through a waveguide means 104 such as a coaxial cable.

  A processing gas supply path 115 is connected to the plasma generation unit of the vacuum processing chamber 102, and the processing gas supply path 115 is connected to the processing gas source 110 and the inert gas source 111. A controller 112 and an introduction valve 113 are provided. In this case, the processing gas introduction path to which the processing gas source 110 and the inert gas source 111 are connected is combined into one by the collective piping unit 114. In addition, when it is better to supply the inert gas at a position different from the processing gas, the gas introduction path may be divided.

  Although the processing gas supply system is illustrated as one set, the processing gas source 110, the mass flow controller 112, and the introduction valve 113 are configured by a plurality of paths so that a plurality of gases can be introduced independently while controlling the flow rate. can do. A vacuum exhaust system is connected to the lower part of the vacuum processing chamber 102. In this example, a variable valve 121, a turbo molecular pump 122, and a dry pump 123 are sequentially connected.

  Further, the plasma etching apparatus has a control device 124, and the control device 124 receives a signal from a pressure sensor 109 attached to the vacuum processing chamber 102, and is introduced in association with the vacuum transfer chamber 101 and the vacuum processing chamber 102. The valves 113 and 119, the mass flow controllers 112 and 117, the variable valve 121 and the like are controlled.

  FIG. 3 is a diagram for explaining an operation method (first embodiment) of the plasma etching apparatus shown in FIG. A sample is carried into a vacuum transfer chamber 101 evacuated to an inert gas atmosphere of a predetermined pressure via a load lock chamber (not shown). As described above, the vacuum processing chamber 102 is evacuated by the turbo molecular pump 123, and in this state, that is, the vacuum processing chamber 102 is evacuated and there is no sample in the processing chamber 102. Zero point correction for resetting the output value of the provided pressure sensor 109 is performed (time point f1 in FIG. 3). Note that it is also possible to perform zero pressure correction individually by evacuating the pressure sensor 109 with the pressure sensor 109 disconnected from the vacuum processing chamber 102 (see FIG. 2).

  Thereafter, an inert gas, which is a sample transporting gas, is supplied from the inert gas supply source 110 into the vacuum processing chamber 102 via the collecting pipe 114 (time point a1 in FIG. 3). At this time, the variable valve 121 is changed to a predetermined opening (time point e1 in FIG. 3), and the gate valve 107 is opened (time point b1 in FIG. 3). By opening the gate valve 107, the inert gas in the vacuum transfer chamber 101 maintained at a high pressure flows into the vacuum processing chamber 102. However, since the exhaust amount in the vacuum processing chamber 102 is large, the inside of the vacuum processing chamber 102 The pressure does not rise so much.

  Thereafter, the sample is transferred to the sample stage 108 (time point c1 in FIG. 3), the gate valve 107 is closed (time point b2 in FIG. 3), and the etching process gas is supplied in a state where the sample transfer gas is allowed to flow into the vacuum processing chamber 102. Supply (time point d1 in FIG. 3). At this time, the sample transport gas stops after providing a predetermined lap time after supplying the etching gas (time point a2 in FIG. 3). At this time, the pressure in the processing chamber is adjusted to a predetermined etching processing start pressure, and the etching processing is started.

  When the etching process is finished and the sample is carried out, the procedure is executed in the reverse order. That is, after the etching process is completed, the variable valve is changed to a predetermined opening degree while the etching process gas is kept flowing (time point e2 in FIG. 3), and the sample transfer gas is supplied before the etching process gas is stopped. (Time point a3 in FIG. 3), the etching process gas is stopped after a predetermined lap time (time point d2 in FIG. 3).

  After that, when the inside of the vacuum processing chamber 102 is in a sample transfer gas atmosphere (for example, when a predetermined time has elapsed), the gate valve 107 is opened (time point b3 in FIG. 3), and the sample is carried out of the vacuum processing chamber 102 (FIG. 3). C2). After the sample transport, the gate valve 107 is closed (time point b4 in FIG. 3), and the supply of the cleaning gas is started before the sample transport gas is stopped (time point d3 in FIG. 3). Thereafter, a predetermined lapping time is provided to stop the sample transport gas (time point a4 in FIG. 3), and a cleaning process is performed. When the cleaning process ends, the supply of the cleaning gas is stopped (time d4 in FIG. 3), the variable valve 121 is fully opened (time e3 in FIG. 3), and high vacuum evacuation is performed. Thereafter, the zero point correction of the pressure sensor 109 for the sample to be processed next is performed (time point f2 in FIG. 3).

  In this manner, in the sequence shown in FIG. 3, the zero point correction (time point f1 in FIG. 3) of the pressure sensor 109 is performed when the vacuum processing chamber 102 is depressurized before the sample is carried into the vacuum processing chamber 102. Thereafter, the opening degree of the variable valve 121 is changed to a predetermined opening degree (time point e1 in FIG. 3), and Ar gas that is a sample transporting gas is supplied (time point a1 in FIG. 3).

  Thereafter, in the conventional sequence shown in FIG. 6, the gate valve is opened (time point b1 in FIG. 6), the sample is loaded (time point c1 in FIG. 6), the gate valve is closed (time point b2 in FIG. 6), The gas supply is stopped (time point a2 in FIG. 6). However, in the sequence of the present invention, the Ar gas as the sample transport gas is continuously supplied, and the etching processing gas is supplied without performing high vacuum evacuation (time point d1 in FIG. 3).

  After supplying the etching gas, the Ar gas is stopped after providing a lap time of, for example, about 0.2 to 2 seconds in consideration of the response time of the gas supply system (time point a2 in FIG. 3). At this time, the pressure in the processing chamber is adjusted to a predetermined etching processing start pressure.

 Thereafter, the sample is processed in the same manner as in the conventional sequence, and the sample is carried out in the reverse procedure. As a result, the number of generated foreign matters was 9 when the particle size was 0.13 μm or more and 1 when the particle size was 1.0 μm or more.

In the case of the conventional sequence, the number of generated foreign matters was 20 when the particle size was 0.13 μm or more and 5 when the particle size was 1.0 μm or more. Note that it is desirable to change the lap time between the sample transport gas and the processing gas depending on the type of gas to be supplied and the flow rate.

As described above, the method of eliminating the high vacuum exhaust before the sample processing and the zero point correction operation of the pressure sensor 109 and further supplying the sample carrying gas until the start of the supply of the etching processing gas and continuously forming the gas flow. By using, the number of generated foreign matters can be reduced. In addition, the sample transfer gas pressurized in the vacuum transfer chamber 101 in accordance with the opening / closing operation of the gate valve 107 when the sample is carried in / out between the vacuum transfer chamber 101 and the vacuum processing chamber 102 is supplied to the vacuum processing chamber. The foreign matter generated by flowing into the gas can be reduced and the throughput can be improved. In the first embodiment, Ar gas is used as the sample transport gas, but N2 gas or the like is used. Also good.

  In the first embodiment, since the gas flow is continued until the etching process gas is supplied, the high-pressure evacuation of the vacuum processing chamber 102 and the zero point correction operation of the pressure sensor 109 are carried into the vacuum processing chamber 102. The conventional example has been changed to be performed before This change has been found to reduce the sequence time, including in-situ cleaning and sample etching, by approximately 15 seconds.

  Therefore, in order to confirm to what extent the difference appears in the throughput between the conventional sequence and the sequence according to the present embodiment, comparative evaluation was performed in continuous processing. Note that the throughput measurement method starts when the first sample is unloaded from the cassette, and is then transferred to the vacuum processing chamber 102 via the vacuum transfer chamber 101, and after performing the etching process, the vacuum transfer chamber 101 again. The time taken for the final sample to be carried into the cassette via Further, as a processing method, an actual product processing was simulated, and a parallel method using one chamber was performed. As a result, by applying the sequence of this embodiment, it was possible to shorten the time by about 17 seconds per wafer from the conventional sequence.

  From the above results, it was found that according to the present embodiment, foreign matter reduction and throughput improvement can be achieved.

  The above example is a sequence including in-situ cleaning with no sample in the vacuum processing chamber 102. However, in-situ cleaning with the sample or in-situ cleaning is not performed, and the sample is continuously processed. When the method is used, it is considered that there is no timing for performing zero point correction of the pressure sensor 109 to be performed before each sample processing.

  In such a case, as shown in FIG. 2, the on-off valve 125 provided below the pressure sensor 109 is closed to disconnect the pressure sensor 109, and then the on-off valve 125 provided above the turbo molecular pump 126 is opened. Thus, only the line reaching the pressure sensor 109 can be decompressed to perform zero point correction. 2 that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 4 is a diagram for explaining a method of operating the plasma etching apparatus (second embodiment). 4, the same reference numerals as those in FIG. 3 indicate the same time points. The difference from FIG. 3 is that gas switching at the time of supply and stop of the sample transport gas and the etching process gas is performed by increasing or decreasing in stages (two stages in the figure). Here, when the gas is switched stepwise, the supply amount of one gas is increased stepwise and the supply amount of the other gas is decreased stepwise so that the pressure in the vacuum processing chamber 102 becomes substantially constant. It is supposed to be.

  According to this operation method, since the gas switching time is overlapped as in the case of the first embodiment, the gas flow in the empty processing chamber 102 is not interrupted. For this reason, the effect of suppressing the adhesion of foreign matter can be obtained as in the first embodiment, and the pressure fluctuation in the vacuum processing chamber 102 can be suppressed by changing the gas flow rate stepwise, and the inside of the vacuum processing chamber 102 It becomes easy to control the processing pressure.

  FIG. 5 is a diagram for explaining a method of operating the plasma etching apparatus (third embodiment). In FIG. 5, the same reference numerals as those in FIG. 3 indicate the same time points. The difference from FIG. 3 is that the gas switching is made more continuous. According to this embodiment, the same effect as that of the second embodiment can be obtained, and the gas flow rate can be changed smoothly, so that the processing gas and the sample can be maintained while maintaining the pressure in the processing chamber substantially constant. Replacement with carrier gas can be performed.

  As described above, according to the present embodiment, the sample is transported in the atmosphere of the sample transport gas, and switching between the sample transport gas and the processing gas in the processing chamber before or after the transport of the sample is performed. The gas is switched by overlapping (wrapping) timing, and the zero point correction of the pressure in the vacuum processing chamber is performed in the sequence. Thereby, the gas can be switched without interrupting the gas flow in the processing chamber. For this reason, it can suppress that a foreign material is exhausted as it is along a gas flow, and adheres to a sample. Further, zero point correction can be performed in the sequence, and the gas switching time can be shortened to improve the throughput.

101 Vacuum transfer chamber 102 Vacuum processing chamber
103 high frequency power supply
104 Waveguide means
105 Antenna 106 Lid member 107 Gate valve 108 Sample stage
109 Pressure sensor 110, 111 Processing gas source, inert gas source 112, 117 Mass flow controller 113, 119 Introduction valve 114 Collecting piping part 115 Processing gas supply path 116 Inert gas source 118 Inert gas gas introduction path 120 Turbo molecular pump 121 Variable Valve 122 Turbo molecular pump 123 Dry pump 124 Controller 125 Open / close valve 126 Turbo molecular pump

Claims (3)

A vacuum processing chamber having a gas supply mechanism for supplying a gas for sample processing and a gas for sample transport;
Plasma generating means for supplying high frequency energy into the vacuum chamber and generating plasma;
A vacuum transfer chamber having one end connected to the lock chamber and the other end connected to the vacuum processing chamber via a gate valve;
Exhaust means for exhausting the gas in the vacuum transfer chamber and exhaust means for exhausting the gas in the vacuum processing chamber via a variable valve;
A pressure sensor for measuring the pressure in the vacuum processing chamber;
The sample in the cassette is carried into the vacuum processing chamber through the lock chamber and the vacuum transfer chamber, and the processed sample that has been vacuum processed in the vacuum processing chamber is carried out through the vacuum transfer chamber and the lock chamber. In the operation method of the vacuum processing apparatus,
Release the variable valve to a predetermined opening to reduce the pressure in the vacuum processing chamber and perform zero point correction to reset the output value of the pressure sensor when the pressure reduction is completed,
After that, the sample transport gas is supplied via the gas supply mechanism, the gate valve is released in the supplied state, the sample is loaded, and the sample is transported with the gate valve closed after the sample is loaded. The sample processing gas is supplied in a state in which the supply of the sample gas is continued, and then the supply of the sample transport gas is stopped, and then the plasma treatment is performed.
A method for operating a plasma processing apparatus, comprising: supplying a sample transporting gas after the plasma processing is completed and prior to stopping the supply of the sample processing gas. In the operating method of the plasma processing apparatus of Claim 1,
The process of supplying the sample processing gas while continuing the supply of the sample transporting gas and then stopping the supply of the sample transporting gas gradually reduces the supply of the sample transporting gas and performs the sample processing. A method for operating a plasma processing apparatus, characterized in that the supply of a gas for use is gradually increased and the supply of a sample transport gas is stopped. The operation method of the plasma processing apparatus according to claim 1, wherein after the plasma processing is finished, the processing for supplying the sample transporting gas prior to stopping the supply of the sample processing gas gradually decreases the supply of the sample processing gas. And a method for operating the plasma processing apparatus, characterized in that the sample transport gas is gradually increased and supplied.

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