JP2011243834A - Plasma processing apparatus, substrate holding mechanism, and substrate position shift detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection precision of a position shift of a substrate by eliminating an effect of pressure loss in a gas passage for heat transfer gas.SOLUTION: There are provided a gas passage 352 for supplying gas from a gas supply source therethrough to the gap between a mount table 300 and a processing target substrate held on a substrate holding surface of the mount table 300, plural gas holes 354 formed in the substrate holding surface of the mount table to guide the gas from the gas passage onto a substrate holding surface Ls, plural pressure detecting holes 370a to 370b formed at the outside of a gas hole forming area R in the substrate holding surface to detect a pressure applied to the back surface of the substrate, and pressure sensors 380a to 380d connected to the pressure detecting holes. A position shift of the substrate is detected on the basis of the detected pressure from the pressure sensors.

Description

  The present invention relates to a plasma processing apparatus that performs plasma processing on a large substrate such as a glass substrate for a flat panel display (FPD), a substrate holding mechanism, and a substrate misalignment detection method.

  In the manufacture of FPD panels, pixel devices or electrodes and wirings are generally formed on a substrate made of an insulator such as glass. Of these various panel manufacturing processes, fine processing such as etching, CVD, ashing, and sputtering is performed by a plasma processing apparatus. The plasma processing apparatus, for example, places a substrate on a mounting table including a susceptor that constitutes a lower electrode in a depressurized processing container, and supplies high frequency power to the susceptor, thereby generating plasma of a processing gas on the substrate. Then, a predetermined process such as etching is performed on the substrate by the plasma.

  In this case, it is necessary to control the temperature of the substrate to be constant while suppressing a temperature rise due to heat generation during plasma processing. For this reason, a coolant whose temperature is controlled by the chiller is circulated and supplied to the coolant passage in the mounting table, and at the same time, a gas having good heat transfer property (heat transfer gas) such as He gas is supplied to the back surface of the substrate through the mounting table. Therefore, a method of indirectly cooling the substrate is often used. Since this cooling method requires that the substrate be fixed and held on the mounting table against the He gas supply pressure, a substrate holding unit is provided on the mounting table. For example, the substrate holding unit holds the substrate by electrostatic attraction force. The substrate is sucked and held on the surface.

  If the substrate is displaced with respect to the substrate holding surface on the mounting table, the substrate holding surface is exposed on the susceptor. If high-frequency power is applied to the susceptor in this state to generate plasma, abnormal discharge will occur. May occur and damage the susceptor. Therefore, if such a position shift of the substrate can be detected before the plasma is generated, the occurrence of abnormal discharge can be prevented in advance.

  Since the FPD substrate is much larger than the semiconductor wafer, there is a problem that even if the technology developed for the semiconductor wafer is applied as it is, the positional deviation of the substrate cannot be detected accurately. For example, as in the technique described in Patent Document 1, a pressure measurement hole is provided in the upper part of the mounting table, and a pressure measurement gas is supplied between the mounting table and the semiconductor wafer through the pressure measurement hole to thereby adjust the pressure of the pressure measurement gas. There is something to monitor. In this method, for example, when there is no semiconductor wafer or when the electrostatic holding force is small, the pressure measurement gas leaks from the pressure measurement hole and the pressure decreases, so the semiconductor on the mounting table is monitored by monitoring the pressure. It detects the presence / absence of the wafer and the holding state, but cannot detect even the positional deviation of the semiconductor wafer. The technique described in Patent Document 2 also detects a pressure by providing a pressure measurement hole in the upper part of the mounting table, but this cannot be detected until the positional deviation as well.

  In order to accurately detect such misalignment of the FPD substrate, as shown in FIGS. 16A and 16B of Patent Document 3, misalignment detection is performed at the four corners of the frame portion surrounding the gas hole formation region of the heat transfer gas. Development of a mounting table in which holes are provided so that these displacement detection holes communicate with a recessed space (a space where heat transfer gas is discharged from the gas holes) in the gas hole forming region is also underway. According to this, when the substrate is displaced, gas leaks from the displacement detection hole, so that the pressure of the gas flow path connected to the gas hole also changes. This is monitored by a built-in manometer of the pressure adjusting valve (PCV) to detect the positional deviation of the substrate.

Japanese Patent Laid-Open No. 04-359539 JP 07-2331032 A JP 2008-172170 A

  However, in recent years, the size of the FPD substrate has been further increased, and accordingly, the size of the mounting table has been increased more than ever. Such a trend toward larger devices is expected to continue. As the apparatus becomes larger in this manner, the number of gas holes for the heat transfer gas is increased, and the gas flow path for supplying the heat transfer gas to these gas holes must be lengthened.

  However, the longer the gas flow path becomes, the worse the conductance becomes. Therefore, the pressure loss due to the gas flow path increases, and it becomes difficult to supply the heat transfer gas to the back surface of the substrate at a desired pressure. For this reason, the difference in the leakage flow rate of heat transfer gas between when the substrate is misaligned and when it is not misaligned is small, making it difficult to detect the substrate misalignment and reducing the detection accuracy. There is a problem of end.

  Therefore, the present invention has been made in view of such a problem, and an object of the present invention is to improve the accuracy of detection of substrate displacement by eliminating the effect of pressure loss in the gas flow path of the heat transfer gas. An object of the present invention is to provide a plasma processing apparatus and the like that can be used.

  In order to solve the above-described problems, according to an aspect of the present invention, there is provided a substrate holding mechanism for mounting and holding a rectangular substrate to be processed in a space where plasma is generated. A rectangular mounting table, a gas flow path for supplying gas from a gas supply source between the mounting table and the substrate to be processed held on the substrate holding surface, and a substrate holding surface of the mounting table And a plurality of gas holes for guiding the gas from the gas flow path onto the substrate holding surface, and formed outside the gas hole forming region on the substrate holding surface, and applying pressure on the back surface of the substrate to be processed. A plurality of pressure detection holes to be detected, a pressure sensor connected to the plurality of pressure detection holes, and a position shift detection means for detecting a position shift of the substrate to be processed based on a detected pressure from the pressure sensor; Substrate holding characterized by comprising Structure is provided.

  In order to solve the above-mentioned problem, according to another aspect of the present invention, there is provided a substrate positional deviation detection method in a substrate holding mechanism for mounting and holding a rectangular substrate to be processed in a space where plasma is generated, The substrate holding mechanism is for supplying a gas from a gas supply source between the rectangular mounting table for mounting and holding the substrate to be processed, and the mounting table and the substrate to be processed held on the substrate holding surface. A gas flow path, a plurality of gas holes formed on the substrate holding surface of the mounting table and guiding the gas from the gas flow path onto the substrate holding surface, and an outside of the gas hole forming region on the substrate holding surface A plurality of pressure detection holes for detecting pressure applied to the back surface of the substrate to be processed, pressure sensors connected to the plurality of pressure detection holes, and a flow rate regulator for adjusting a gas flow rate from the gas supply source And the pressure sensor On the basis of the detection pressure performs the positional deviation detection of the substrate, the substrate displacement detection method characterized by adjusting the gas flow rate by the flow regulator is provided.

  In order to solve the above problems, according to another aspect of the present invention, by introducing a processing gas into a processing chamber and generating a plasma of the processing gas, the insulation placed and held on a mounting table in the processing chamber is obtained. A plasma processing apparatus for performing predetermined plasma processing on a substrate to be processed comprising a body for supplying a gas from a gas supply source between the mounting table and the substrate to be processed held on the substrate holding surface. A gas flow path, a plurality of gas holes formed on the substrate holding surface of the mounting table and guiding the gas from the gas flow path onto the substrate holding surface, and an outside of the gas hole forming region on the substrate holding surface A plurality of pressure detection holes for detecting pressure applied to the back surface of the substrate to be processed, a pressure sensor connected to the plurality of pressure detection holes, and the substrate to be processed based on the detected pressure from the pressure sensor Misalignment detection The plasma processing apparatus characterized by comprising a displacement detection means for performing is provided.

  According to the present invention, a plurality of pressure detection holes are provided in addition to the gas holes for the heat transfer gas, and the substrate back surface pressure can be directly detected from these pressure detection holes. Can be detected. Thereby, the position shift of the substrate to be processed can be detected without being affected by the pressure loss due to the gas hole for the heat transfer gas. In addition, since the plurality of pressure detection holes are formed outside the gas hole formation region, the pressure changes when the substrate to be processed is slightly displaced, so that it is easy to detect displacement.

  According to the present invention, it is possible to eliminate the influence of the pressure loss in the gas flow path of the heat transfer gas and improve the accuracy of detecting the positional deviation of the substrate, so that the present invention can be applied to a larger apparatus.

1 is an external perspective view of a processing apparatus according to an embodiment of the present invention. It is sectional drawing of the process chamber which comprises the plasma processing apparatus in the embodiment. It is a figure for demonstrating the structural example of the heat transfer gas supply mechanism in the embodiment. It is the figure which looked at the surface of the mounting base shown in FIG. 3 from upper direction, Comprising: The state in which the board | substrate is not mounted is shown. It is the figure which looked at the surface of the mounting base shown in FIG. 3 from upper direction, Comprising: The state in which the board | substrate was mounted is shown. It is the figure which showed the relationship between the He gas pressure set using the pressure sensor with a built-in pressure control valve (PCV), and the He gas pressure in a substrate back surface. It is a flowchart which shows the main routine of the heat transfer gas control in the embodiment. It is a flowchart which shows the subroutine of the board | substrate deviation determination process shown in FIG. It is a figure for demonstrating a position shift pattern, Comprising: The specific example in case the board | substrate parallel shift | offset | difference of one direction generate | occur | produces is shown. It is a figure for demonstrating a position shift pattern, Comprising: Another specific example in case the board | substrate parallel shift of one direction generate | occur | produces is shown. It is a figure for demonstrating a position shift pattern, Comprising: The specific example in case the board | substrate parallel shift | offset | difference of two directions has shown is shown. It is a figure for demonstrating a position shift pattern, Comprising: The other specific example at the time of the board | substrate parallel shift | offset | difference of two directions showing is shown. It is a figure for demonstrating a position shift pattern, Comprising: The specific example in case the board | substrate skew deviation generate | occur | produces is shown. It is a figure for demonstrating a position shift pattern, Comprising: The other example when a board | substrate skew deviation generate | occur | produces is shown. It is sectional drawing for demonstrating the other structural example of the pressure detection hole in the embodiment. It is sectional drawing for demonstrating the modification of FIG. It is sectional drawing for demonstrating the modification of FIG. It is sectional drawing for demonstrating the modification of FIG. It is sectional drawing for demonstrating the modification of FIG. It is a figure for demonstrating the arrangement position of a pressure detection hole. It is a perspective view which shows the structural example of the flow-path piece fitted in a pressure detection hole.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

(Configuration example of plasma processing equipment)
First, an embodiment when the present invention is applied to a multi-chamber type processing apparatus including a plurality of plasma processing apparatuses will be described with reference to the drawings. FIG. 1 is an external perspective view of a processing apparatus 100 according to the present embodiment. The processing apparatus 100 shown in the figure includes three plasma processing apparatuses for performing plasma processing on a flat panel display substrate (FPD substrate) G. Each plasma processing apparatus includes a processing chamber 200.

  In the processing chamber 200, for example, a mounting table for mounting the FPD substrate G is provided, and a shower head for introducing a processing gas (for example, process gas) is provided above the mounting table. The mounting table includes a susceptor constituting the lower electrode, and the shower head provided in parallel with the susceptor also functions as the upper electrode. Each processing chamber 200 may perform the same processing (for example, etching processing) or different processing (for example, etching processing and ashing processing). A specific configuration example in the processing chamber 200 will be described later.

  Each processing chamber 200 is connected via a gate valve 102 to a side surface of a transfer chamber 110 having a polygonal cross section (for example, a rectangular cross section). A load lock chamber 120 is further connected to the transfer chamber 110 via a gate valve 104. A substrate carry-in / out mechanism 130 is provided adjacent to the load lock chamber 120 via a gate valve 106.

  Two indexers 140 are provided adjacent to the substrate carry-in / out mechanism 130, respectively. A cassette 142 for storing the FPD substrate G is placed on the indexer 140. The cassette 142 is configured to accommodate a plurality of (for example, 25) FPD substrates G.

  When plasma processing is performed on the FPD substrate G by using such a plasma processing apparatus, first, the FPD substrate G in the cassette 142 is carried into the load lock chamber 120 by the substrate carry-in / out mechanism 130. At this time, if there is a processed FPD substrate G in the load lock chamber 120, the processed FPD substrate G is carried out of the load lock chamber 120 and replaced with an unprocessed FPD substrate G. When the FPD substrate G is carried into the load lock chamber 120, the gate valve 106 is closed.

  Next, after reducing the pressure in the load lock chamber 120 to a predetermined degree of vacuum, the gate valve 104 between the transfer chamber 110 and the load lock chamber 120 is opened. Then, after the FPD substrate G in the load lock chamber 120 is loaded into the transfer chamber 110 by a transfer mechanism (not shown) in the transfer chamber 110, the gate valve 104 is closed.

  The gate valve 102 between the transfer chamber 110 and the processing chamber 200 is opened, and the unprocessed FPD substrate G is loaded onto the mounting table in the processing chamber 200 by the transfer mechanism. At this time, if there is a processed FPD substrate G, the processed FPD substrate G is unloaded and replaced with an unprocessed FPD substrate G.

  In the processing chamber 200, a processing gas is introduced into the processing chamber through a shower head, and high frequency power is supplied to the lower electrode or the upper electrode, or both the upper electrode and the lower electrode, so that the lower electrode, the upper electrode, During this time, plasma of the processing gas is generated to perform predetermined plasma processing on the FPD substrate G held on the mounting table.

(Configuration example of processing chamber)

  Next, a specific configuration example of the processing chamber 200 will be described with reference to the drawings. Here, processing when the plasma processing apparatus of the present invention is applied to a capacitively coupled plasma (CCP) etching apparatus that etches an FPD insulating substrate (hereinafter, also simply referred to as “substrate”) G such as a glass substrate, for example. A configuration example of the chamber will be described. FIG. 2 is a cross-sectional view illustrating a schematic configuration of the processing chamber 200.

  The processing chamber 200 shown in FIG. 2 includes a processing container 202 having a substantially rectangular tube shape made of aluminum whose surface is anodized (anodized), for example. The processing container 202 is grounded. A mounting table 300 having a susceptor 310 that constitutes a lower electrode is disposed at the bottom of the processing chamber 200. The mounting table 300 functions as a substrate holding mechanism that fixes and holds the rectangular substrate G, and is formed in a rectangular shape corresponding to the rectangular substrate G. A specific configuration example of the mounting table will be described later.

  Above the mounting table 300, a shower head 210 that functions as an upper electrode is disposed so as to face the susceptor 310 in parallel. The shower head 210 is supported on the upper portion of the processing container 202, has a buffer chamber 222 therein, and has a plurality of discharge holes 224 for discharging a processing gas on the lower surface facing the susceptor 310. The shower head 210 is grounded and forms a pair of parallel plate electrodes together with the susceptor 310.

  A gas inlet 226 is provided on the upper surface of the shower head 210, and a gas inlet tube 228 is connected to the gas inlet 226. A processing gas supply source 234 is connected to the gas introduction pipe 228 via an open / close valve 230 and a mass flow controller (MFC) 232.

The processing gas from the processing gas supply source 234 is controlled to a predetermined flow rate by a mass flow controller (MFC) 232 and is introduced into the buffer chamber 222 of the shower head 210 through the gas introduction port 226. As the processing gas (etching gas), for example, a gas usually used in this field such as a halogen-based gas, O ₂ gas, Ar gas, or the like can be used.

  A gate valve 102 for opening and closing the substrate loading / unloading port 204 is provided on the side wall of the processing chamber 200. In addition, an exhaust port is provided below the side wall of the processing chamber 200, and an exhaust device 209 including a vacuum pump (not shown) is connected to the exhaust port via an exhaust pipe 208. By exhausting the inside of the processing chamber 200 by the exhaust device 209, the inside of the processing chamber 200 can be maintained in a predetermined vacuum atmosphere (for example, 10 mTorr = about 1.33 Pa) during the plasma processing.

(Configuration example of a mounting table to which a substrate holding mechanism is applied)
Here, a specific configuration example of the mounting table 300 to which the substrate holding mechanism according to the present invention is applied will be described with reference to FIGS. FIG. 3 is a diagram illustrating a configuration example of the heat transfer gas supply mechanism of the mounting table 300. FIG. 3 shows a simplified cross section of the upper part of the mounting table 300 shown in FIG. In FIG. 3, the electrostatic holding part 320 shown in FIG. 4A and 4B are views of the surface of the mounting table 300 as viewed from above. FIG. 4A shows a state where the substrate G is not placed, and FIG. 4B shows a state where the substrate G is placed without positional deviation.

  As shown in FIG. 2, the mounting table 300 includes an insulating base member 302 and a rectangular block-shaped susceptor 310 made of a conductor (for example, aluminum) provided on the base member 302. The side surface of the susceptor 310 is covered with an insulating film 311 as shown in FIG.

  On the susceptor 310, an electrostatic holding unit 320 is provided as an example of a substrate holding unit that holds the substrate G on the substrate holding surface. The electrostatic holding unit 320 is configured, for example, by sandwiching an electrode plate 322 between a lower dielectric layer and an upper dielectric layer. A rectangular frame-shaped outer frame 330 made of, for example, an insulating member made of ceramic or quartz is disposed so as to constitute an outer frame of the mounting table 300 and surround the base member 302, the susceptor 310, and the electrostatic holding unit 320. Is done.

  A direct current (DC) power source 315 is electrically connected to the electrode plate 322 of the electrostatic holding unit 320 via a switch 316. For example, the switch 316 can switch between the DC power source 315 and the ground potential with respect to the electrode plate 322. A high-frequency cutoff unit (illustrated) that blocks high-frequency waves from the susceptor 310 side between the electrode plate 322 and the direct current (DC) power source 315 and prevents leakage of high-frequency waves on the susceptor 310 side to the DC power source 315 side. No) may be provided. The high-frequency cutoff unit is preferably constituted by a resistor having a high resistance value of 1 MΩ or more or a low-pass filter that passes direct current.

  When the switch 316 is switched to the DC power source 315 side, a DC voltage from the DC power source 315 is applied to the electrode plate 322. When this DC voltage is a positive voltage, negative charges (electrons and negative ions) are accumulated on the upper surface of the substrate G so as to be attracted. As a result, an electrostatic attracting force, that is, a Coulomb force attracting each other with the substrate G and the upper dielectric layer sandwiched between the negative surface charge on the upper surface of the substrate G and the electrode plate 322 acts. It is sucked and held on the mounting table 300. When the switch 316 is switched to the ground side, the electrode plate 322 is neutralized, and accordingly, the substrate G is also neutralized, and the Coulomb force, that is, the electrostatic adsorption force is released.

  The output terminal of the high frequency power supply 314 is electrically connected to the susceptor 310 via the matching unit 312. The output frequency of the high frequency power supply 314 is selected to be a relatively high frequency, for example, 13.56 MHz. A plasma PZ of a processing gas is generated on the substrate G by the high frequency power from the high frequency power source 314 applied to the susceptor 310, and a predetermined plasma etching process is performed on the substrate G.

  A refrigerant flow path 340 is provided inside the susceptor 310, and a refrigerant adjusted to a predetermined temperature flows from the chiller device (not shown) through the refrigerant flow path 340. With this refrigerant, the temperature of the susceptor 310 can be adjusted to a predetermined temperature.

  The mounting table 300 includes a heat transfer gas supply mechanism that supplies heat transfer gas (for example, He gas) at a predetermined pressure between the substrate holding surface of the electrostatic holding unit 320 and the back surface of the substrate G. The heat transfer gas supply mechanism supplies the heat transfer gas to the back surface of the substrate G at a predetermined pressure via the gas flow path 352 inside the susceptor 310.

  Specifically, the heat transfer gas supply mechanism is configured as shown in FIG. 3, for example. That is, a large number of gas holes 354 are provided in the upper surface of the susceptor 310 and the electrostatic holding portion 320 (not shown in FIG. 3) above the susceptor 310, and these gas holes 354 communicate with the gas flow path 352. For example, a large number of gas holes 354 are arranged at predetermined intervals in a gas hole forming region R spaced inward from the outer periphery of the substrate holding surface Ls.

  For example, a He gas supply source 366 that supplies He gas as a heat transfer gas is connected to the gas flow path 352 via a pressure control valve (PCV) 362. The pressure adjustment valve (PCV) 362 adjusts the flow rate so that the pressure of the He gas supplied to the gas hole 354 side becomes a predetermined pressure.

  Although not shown, the pressure adjustment valve (PCV) 362 includes, for example, a pressure sensor that measures the pressure of the heat transfer gas flowing through the gas flow path 352, a flow rate adjustment valve (for example, a piezo valve), and a flow meter (not shown). (Flow meter) and a controller for controlling a piezo valve which is a flow rate adjusting valve are integrated.

  Although FIG. 3 shows an example in which a pressure adjustment valve (PCV) 362 in which a pressure sensor and a flow rate adjustment valve are integrated in the gas flow path 352 is shown, the present invention is not limited to this, and the gas flow path 352 is not limited thereto. The pressure sensor and the flow rate adjusting valve may be provided separately.

  An example of such a pressure sensor is a manometer (for example, a capacitance manometer (CM)). As this pressure sensor, other manometers can be used, and the flow rate adjusting valve is not limited to the piezo valve but may be a solenoid valve, for example.

  These pressure adjustment valves (PCV) 362 and He gas supply source 366 are connected to a control unit 400 that controls each part of the processing apparatus 100. The control unit 400 controls the He gas supply source 366 to flow out He gas, sets the set pressure in the pressure adjustment valve (PCV) 362, and sets the He gas to a predetermined flow rate in the pressure adjustment valve (PCV) 362. It is adjusted and supplied to the gas flow path 352. The controller of the pressure adjustment valve (PCV) 362 controls the He gas flow rate by controlling the piezo valve so that the gas pressure becomes a set pressure by, for example, PID control. Thereby, the He gas is supplied to the back surface of the substrate G at a predetermined pressure through the gas flow path 352 and the gas hole 354.

  By the way, in such a heat transfer gas supply mechanism, since the pressure of the gas flow path 352 can be measured with a manometer built in the pressure adjusting valve (PCV) 362, the flow rate of He gas is adjusted based on the measured He gas pressure. In addition to being controllable, it is also possible to monitor the He gas leakage flow rate using a built-in flow meter. Since the He gas leakage flow rate varies depending on the displacement of the substrate G, the displacement of the substrate G can be detected by monitoring the He gas leakage flow rate.

  However, in recent years, the size of the substrate G is further increased, and accordingly, the size of the mounting table 300 is also increased more than before. In order to cope with this, the number of He gas holes 354 must be increased, and the gas flow path 352 for supplying He gas to these gas holes 354 must be lengthened.

  As the gas flow path 352 becomes longer as described above, the conductance becomes worse. Therefore, the pressure loss due to the gas flow path 352 increases, and it is difficult to supply He gas to the back surface of the substrate G at a desired pressure. For this reason, the difference in the He gas leakage flow rate between when the substrate G is displaced and when it is not displaced becomes small, making it difficult to detect the displacement of the substrate G and reducing the detection accuracy. There is a problem that it ends up.

  Here, it demonstrates in detail, referring the experimental result performed using the large sized substrate processing apparatus. FIG. 5 is a graph showing the relationship between the He gas set pressure set using the pressure sensor built in the pressure regulating valve (PCV) 362 and the He gas pressure (substrate back pressure) generated on the back surface of the substrate G. Is. In FIG. 5, the black circle graph is the target value of the substrate back surface pressure. On the other hand, the white circle graph represents the substrate back surface pressure in the vicinity of the gas hole 354 close to the outer frame portion 330, and the white square graph represents the substrate back surface pressure in the vicinity of the outer frame portion 330 further than the gas hole 354.

  As shown in the graph shown by the black circle in FIG. 5, the substrate back surface pressure is preferably the same as the set pressure of the pressure adjustment valve (PCV) 362. However, when the conductance is reduced due to the pressure loss of the gas flow path 352 and the gas hole 354 as in a large substrate processing apparatus, the pressure on the back surface of the substrate is lower than the set pressure as shown by the white circle in FIG. End up. In the vicinity of the outer frame 330 from the gas hole 354, the substrate back surface pressure further decreases. According to this, it turns out that the flow path 352 becomes long and conductance worsens and the substrate back surface pressure decreases further from the center of the substrate G toward the outside.

  Therefore, in the present embodiment, as shown in FIG. 3, a plurality of pressure detection holes 370 penetrating the substrate mounting surface Ls are disposed outside the gas hole forming region R on the substrate mounting surface Ls of the mounting table 300. The pressure detection hole 370 directly detects the back pressure of the substrate G (here, the pressure between the surface of the substrate placement surface Ls and the back surface of the substrate G). According to this, it is possible to provide a plurality of pressure detection holes 370 at a portion where the decrease in the pressure on the back surface of the substrate is large and detect the pressure at that portion.

  Furthermore, if the pressure regulating valve (PCV) 362 is controlled using the substrate back surface pressure detected from the pressure detection hole 370, the flow rate of He gas can be controlled to compensate for the decrease in the substrate back surface pressure due to pressure loss. . In addition, the detected substrate back pressure can also be used for detecting the displacement of the substrate G. According to this, since the position shift can be detected by the measured pressure on the back surface of the substrate without being affected by the pressure loss, the detection accuracy of the position shift can be improved. Further, by controlling the flow rate of the He gas while directly detecting the substrate back surface pressure, the time until the substrate back surface pressure is stabilized can be shortened.

  Hereinafter, the structure of the mounting table 300 of this embodiment provided with such a pressure detection hole 370 will be described in more detail. FIG. 3 shows an example in which four pressure detection holes 370a to 370d are provided independently from the gas hole 354 by a separate system. Each of the pressure detection holes 370a to 370d shown in FIG. 3 is formed to penetrate from the susceptor 310 to the surface of the substrate placement surface Ls.

  The pressure detection holes 370a to 370d here are arranged at four corners of the substrate placement surface Ls as shown in FIG. 4A. These arrangement positions are positions that are hidden by the substrate G when the substrate G is placed without displacement as shown in FIG. 4B. Pressure sensors 380a to 380d shown in FIG. 3 are connected to the pressure detection holes 370a to 370d, respectively. Examples of the pressure sensors 380a to 380d include a capacitance manometer (CM), but other manometers and pressure sensors may be used.

  The detected pressure from each of the pressure sensors 380a to 380d is input to the pressure regulating valve (PCV) 362 via the control unit 400, and the pressure regulating valve (PCV) 362 controls the flow rate of He gas based on these detected pressures. It is supposed to be. By controlling the flow rate of the He gas based on the substrate back pressure directly detected by the pressure sensors 380a to 380d in this way, the time until the substrate back pressure is stabilized can be shortened and maintained at the set pressure after stabilization. can do.

  Further, by separately providing the pressure detection holes 370a to 370d at the four corners of the substrate mounting surface Ls, the pressures from the pressure detection holes 370a to 370d can be detected separately. Based on this, the substrate placement state such as substrate displacement determination is also confirmed. It is also possible to determine a positional deviation pattern (parallel deviation, skew deviation, etc.) of the substrate G.

  Here, a specific example of the heat transfer gas control including the position shift determination of the substrate G will be described with reference to the drawings. FIG. 6 is a flowchart showing a main routine of heat transfer gas control in the present embodiment, and FIG. 7 is a flowchart showing a subroutine of substrate misalignment determination processing shown in FIG. The heat transfer gas control is executed by the control unit 400 after the substrate G is placed on the mounting table 300 and held by electrostatic attraction.

  First, as shown in FIG. 6, the controller 400 starts introducing He gas, which is a heat transfer gas, from the He gas supply source 366 into the gas flow path 352 in Step S110, and in Step S120, the pressure sensors 380a to 380d. Then, while detecting the substrate back surface pressure, flow control by the pressure adjustment valve (PCV) 362 is started so that each detected pressure becomes a set pressure.

  Specifically, the control unit 400 sets the set pressure in the pressure adjustment valve (PCV) 362, outputs the detected pressures from the pressure sensors 380a to 380d in real time, and controls the flow rate of the He gas. That is, when each detected pressure is input from the control unit 400, the pressure adjustment valve (PCV) 362 automatically adjusts the opening of the valve so that each detected pressure becomes the set pressure, thereby adjusting the flow rate of He gas.

  When the supply of the He gas is started in this way, the gas channel 352 or the electrostatic holding unit 320 starts to be filled between the substrate holding surface and the back surface of the substrate G. In this case, the longer the gas flow path 352 is, the longer it takes for the He gas to be completely filled and the pressure to stabilize, but here, the flow rate of the He gas is adjusted while directly detecting the back surface pressure. Since the flow rate is adjusted to increase until it is filled, and the flow rate can be finely adjusted after a certain amount of time, the time until the pressure stabilizes can be shortened.

  Next, the controller 400 confirms the substrate placement state based on the detected pressures of the pressure sensors 380a to 380d (steps S130, S200, S300). That is, first in step S130, the control unit 400 determines whether or not all the detected pressures are balanced. Since the flow rate immediately after the start of He gas introduction increases as described above, the determination in step S130 may be made after waiting for the flow rate to stabilize to some extent (until a predetermined time elapses).

  If it is determined in step S130 that the detected pressures are unbalanced, substrate deviation determination processing is performed in step S200, and substrate deviation error processing is performed in step S300. In the substrate misalignment error process in step S300, the supply of He gas is stopped, and the determination result in step S200 is displayed on the display or notified by an alarm. A specific example of the substrate deviation determination process in step S200 will be described later.

  On the other hand, if it is determined in step S130 that all the detected pressures are balanced, the He gas supply state is confirmed based on the detected pressures of the pressure sensors 380a to 380d (steps S140 and S150). , S170, S172). That is, first, in step S140, it is determined whether all the detected pressures have reached the set pressure.

  If it is determined in step 140 that all the detected pressures have reached the set pressure, it is determined in step S150 whether or not the He gas flow rate of the pressure adjustment valve (PCV) 362 is equal to or less than a predetermined value. At this time, if it is determined that the He gas flow rate is equal to or less than the predetermined value, it is determined in step S160 that the substrate placement state is OK and the He gas supply state is OK, and the processing of the substrate G is started.

  If it is determined in step S140 that any of the detected pressures has not reached the set pressure, or if it is determined in step S150 that the He gas flow rate exceeds a predetermined value, the process of step S170 is performed. Move.

  In step S170, the elapsed time from the start of He gas introduction is compared with a preset timeout time to determine whether or not the timeout time has been exceeded. If it is determined in step S170 that the time-out period has not been exceeded, the flow returns to step S120 to continue He gas flow control. If it is determined in step S170 that the time-out period has been exceeded, an abnormality has occurred, and thus a stability wait error process is performed in step S172.

  For example, if all of the detected pressures are balanced (S130), the He gas flow rate exceeds a predetermined value (S150), and the timeout time is exceeded (S170), the substrate is placed on the mounting table 300. There is a possibility that G is not placed or a substrate G adsorption failure has occurred. Therefore, in such a case, it is assumed that a stability waiting error process is performed in step S172. In the stabilization wait error process, for example, the supply of He gas is stopped, and an error is displayed on the display or an alarm is given.

  After the processing of the substrate G is started based on step S160, the He gas flow rate control based on the detected pressures on the back surface of the substrate from the pressure sensors 380a to 380d is continuously performed. As a result, the substrate back pressure of the He gas is always maintained at the set pressure without being affected by the conductance of the gas flow path 352 and the like. After that, the process waits for the end of the processing of the substrate G in step S162. If it is determined that the processing is ended, the supply of He gas is stopped in step S164, and the flow rate control by the pressure adjustment valve (PCV) 362 is also stopped. A series of electric heating gas control is completed.

  Note that the steps S130, S200, and S300 may be monitored while the substrate G is being processed. According to this, even when a substrate mounting state abnormality occurs during the processing of the substrate G, the risk of abnormal discharge can be reduced.

  Next, a specific example of the substrate deviation determination process shown in FIG. 6 will be described with reference to FIG. Here, the positional deviation pattern of the substrate G is determined according to the imbalance pattern of the detected pressures in the pressure detection holes 370a to 370d detected by the pressure sensors 380a to 380d. The presence / absence of the substrate G on the mounting table 300 and the presence / absence of defective electrostatic attraction of the substrate G are not determined here, and the stability waiting error processing is performed in step S172 as described above.

  As shown in FIG. 7, in the substrate misalignment determination process, it is determined in steps S210, S230, and S250 what imbalance exists in the detected pressures in the pressure detection holes 370a to 370d. More specifically, in step S210, it is determined whether or not the detected pressure is imbalanced between the two parallel corners. In step S230, it is determined whether or not the detected pressure is unbalanced between the three corners and the other one corner. It is determined whether or not there is an imbalance in the detected pressure between the two diagonals.

  If it is determined in step S210 that there is an imbalance in the detected pressure between the two parallel corners, it is determined in step S220 that the substrate is parallelly displaced in one direction. For example, as shown in FIG. 8A, when the substrate G is displaced in parallel in one direction on the pressure detection holes 370c and 370d side, the detection pressures of the pressure detection holes 370a and 370b in the two parallel corners are different from each other. This is because the pressure is lower than the detection pressure of the pressure detection holes 370c and 370d at the corners.

  Also, as shown in FIG. 8B, when the substrate G is displaced in parallel in one direction on the pressure detection holes 370a, 370c side, the detection pressures of the pressure detection holes 370b, 370d in the two parallel corners are different from each other. It becomes lower than the detection pressure of the pressure detection holes 370a and 370c at the two corners. If it is determined in step S220 that the substrate is parallel in one direction, the process returns to the main routine shown in FIG. 6, and the determination result is displayed on the display and notified by an alarm in step S300.

  If it is determined in step S230 that there is an imbalance between the detected pressure at the three corners and the other corner, it is determined at step S240 that the substrate is parallelly displaced in two directions. For example, as shown in FIG. 9A, when the substrate G is displaced in parallel in the two directions of the pressure detection holes 370c and 370d and the pressure detection holes 370a and 370c, the pressure detection holes 370a and 370b at the three corners. This is because the detected pressure of 370d is lower than the detected pressure of the pressure detection hole 370c at the other corner.

  Further, as shown in FIG. 9B, when the substrate G is displaced in parallel in the two directions of the pressure detection holes 370a and 370b and the pressure detection holes 370b and 370d, the pressure detection holes 370a, 370c and 370d at the three corners. Is lower than the detection pressure of the pressure detection hole 370b at the other corner. If it is determined in step S240 that the substrate is parallel in two directions, the process returns to the main routine shown in FIG. 6, and the determination result is displayed on the display and notified by an alarm in step S300.

  If it is determined in step S250 that the detected pressure is not balanced between the two diagonal corners, it is determined in step S260 that the substrate is skewed. For example, as shown in FIG. 10A, when the substrate G is skewed counterclockwise, the detection pressures of the pressure detection holes 370a and 370d in the diagonal two corners are in the other two diagonal corners. This is because the pressure is lower than the detection pressure of the pressure detection holes 370b and 370c.

  When the substrate G is skewed clockwise as shown in FIG. 10B, the pressure detected by the pressure detection holes 370b and 370c at the diagonal two corners is the pressure detection at the other diagonal two corners. It becomes lower than the detected pressure of the holes 370a and 370d. As described above, it is possible to determine the positional deviation pattern of the substrate G based on the imbalance pattern of the detected pressures from the pressure detection holes 370a to 370d. If it is determined in step S260 that the substrate is skewed, the process returns to the main routine shown in FIG. 6. In step S300, the determination result is displayed on the display and notified by an alarm.

  If there is an imbalance in the detected pressure other than steps S210, S230, and S250, a determination error is determined in step S270. In this case, another cause such as a substrate crack or a pressure sensor failure may occur.

  As described above, according to the present embodiment, the pressure on the substrate back surface can be directly detected by disposing the pressure detection holes 370a to 370d at the four corners of the substrate mounting surface Ls independently of the gas holes 354. , Both the flow rate adjustment of the heat transfer gas and the detection of the positional deviation of the substrate G can be performed based on the detected pressure. Thereby, it can fully respond to further enlargement of the mounting table 300. That is, even if the gas flow path 352 becomes longer, the flow rate of the heat transfer gas can be adjusted so as to compensate for the pressure loss of the gas flow path 352, and the accuracy of detecting the displacement of the substrate G can be improved. In addition, since the time until the pressure of the heat transfer gas is stabilized can be shortened, the time required for detecting the displacement of the substrate G can also be shortened.

  The configuration of each of the pressure detection holes 370a to 370d is not limited to that shown in FIG. You may comprise so that He gas may be supplied also to each pressure detection hole 370a-370d. Specifically, for example, as shown in FIG. 11, the pressure detection holes 370 a to 370 d may be connected to the communication path 372. According to this, since the He gas is supplied also from each of the pressure detection holes 370a to 370d to the four corners of the substrate placement surface Ls via the communication path 372, the time until the pressure of the heat transfer gas is stabilized. In addition, when the positional deviation of the substrate G occurs, the leakage flow rate increases, and it becomes easier to detect the positional deviation.

  Further, as shown in FIG. 12, a He gas supply source 366 may be directly connected to each of the pressure detection holes 370 a to 370 d via a pressure adjustment valve (PCV) 362. According to this, since the He gas can be supplied to each of the pressure detection holes 370a to 370d without being affected by the pressure loss of the gas flow path 352, it is possible to shorten the time until the pressure of the heat transfer gas is stabilized, and When the displacement of the substrate G occurs, the leakage flow rate increases, so that it becomes easier to detect the displacement.

  Further, as shown in FIG. 13, each pressure detection hole 370a to 370d is not provided with a pressure sensor, and each pressure detection hole is formed by using a pressure control valve (PCV) 362 having a built-in pressure sensor 363 and a flow meter (flow meter) 364. The pressure from 370a to 370d or the total leakage flow rate may be monitored to detect only whether or not the substrate G is misaligned.

  In addition to the pressure detection holes 370a to 370d, other pressure detection holes for detecting the substrate back surface pressure may be provided. Specifically, as shown in FIG. 14, for example, other pressure detection holes 374 may be provided outside the gas hole formation region R of the substrate placement surface Ls at positions different from the pressure detection holes 370a to 370d. Good. A pressure sensor 382 is connected to the other pressure detection hole 374, and the pressure adjustment valve (PCV) 362 is controlled by the detected pressure.

  According to this, the pressure detection holes 370a to 370d detect only the positional deviation of the substrate G, and the other pressure detection holes 374 detect the back surface pressure for controlling the pressure adjustment valve (PCV) 362. The role can be divided.

  Further, instead of directly connecting the He gas supply source 366 to the pressure detection holes 370a to 370d via the pressure adjusting valve (PCV) 362, the pressure detection holes 370a to 370d and the communication passages 372 are connected as shown in FIG. You may make it connect. Even in this case, since the pressure adjustment valve (PCV) 362 is adjusted by the detected pressure of the other pressure detection hole 374, the time until the heat transfer gas pressure is stabilized can be shortened.

  In addition, as another arrangement position of such other pressure detection holes 374, it arrange | positions in the outer site | part (for example, A1 site | part of FIG. 16) of the gas hole formation area | region R of the board | substrate mounting surface Ls. In this case, only one or a plurality of other pressure detection holes may be provided. In the case where a plurality of gas holes are provided, they may be further arranged at the inner part of the gas hole forming region R (for example, the A2 part in FIG. 16) or at the central part (for example, the A3 part of FIG. 16).

  Further, the pressure detection holes 370a to 370d and the other pressure detection holes 374 described above are preferably larger in diameter than the gas holes 354, but in order to prevent abnormal discharge from occurring when exposed, for example, FIG. Alternatively, a flow channel piece 376 having a large number of holes 378 as shown in FIG. 17 may be fitted. According to this, even if the diameters of the pressure detection holes 370a to 370d and the other pressure detection holes 374 are increased, abnormal discharge at the time of exposure can be prevented. In addition, a decrease in conductance can be prevented by providing a large number of holes 378 in the flow path piece 376.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above-described embodiment, a capacitively coupled plasma (CCP) processing apparatus has been described as an example of a plasma processing apparatus to which the present invention can be applied. The present invention may be applied to an inductively coupled plasma (ICP) processing apparatus capable of generating plasma.

  In addition, the present invention can also be applied to a plasma processing apparatus using helicon wave plasma generation or ECR (Electron Cyclotron Resonance) plasma generation as plasma generation.

  The present invention is applicable to a plasma processing apparatus, a substrate holding mechanism, and a substrate misalignment detection method for performing plasma processing on a large substrate such as a glass substrate for a flat panel display (FPD).

100 processing apparatus 102, 104, 106 gate valve 110 transfer chamber 120 load lock chamber 130 substrate loading / unloading mechanism 140 indexer 142 cassette 200 processing chamber 202 processing container 204 substrate loading / unloading port 208 exhaust pipe 209 exhaust device 210 shower head 222 buffer chamber 224 discharge Hole 226 Gas introduction port 228 Gas introduction pipe 230 On-off valve 232 Mass flow controller (MFC)
234 Processing gas supply source 300 Mounting base 302 Base member 310 Susceptor 311 Insulating coating 312 Matching unit 314 High frequency power supply 315 DC power supply 316 Switch 320 Electrostatic holding part 322 Electrode plate 330 Outer frame part 340 Refrigerant flow path 352 Gas flow path 354 Gas hole 362 Pressure control valve (PCV)
363 Pressure sensor 364 Flow meter
366 He gas supply source 370 Pressure detection hole 370a to 370d Pressure detection hole 372 Communication path 374 Other pressure detection hole 376 Channel piece 378 Many holes 380a to 380d Pressure sensor 382 Pressure sensor 400 Control unit G substrate Ls substrate holding surface R Gas hole formation area

Claims (16)

A substrate holding mechanism for mounting and holding a rectangular substrate to be processed in a space where plasma is generated,
A rectangular mounting table for mounting and holding the substrate to be processed;
A gas flow path for supplying gas from a gas supply source between the mounting table and the substrate to be processed held on the substrate holding surface;
A plurality of gas holes formed on the substrate holding surface of the mounting table for guiding the gas from the gas flow path onto the substrate holding surface;
A plurality of pressure detection holes which are formed outside the gas hole forming region on the substrate holding surface and detect pressure applied to the back surface of the substrate to be processed;
A pressure sensor connected to the plurality of pressure detection holes;
A displacement detection means for detecting a displacement of the substrate to be processed based on a detected pressure from the pressure sensor;
A substrate holding mechanism comprising: The substrate holding mechanism according to claim 1, further comprising a flow rate adjuster that adjusts a gas flow rate from the gas supply source based on a detected pressure from the pressure sensor. The substrate holding mechanism according to claim 2, wherein the pressure detection holes are respectively formed at four corners of the rectangular substrate holding surface. The pressure sensor is a plurality of pressure sensors respectively connected to the pressure detection holes, and detects a back surface pressure of the substrate to be processed at the four corners. Substrate holding mechanism. 5. The substrate holding mechanism according to claim 4, wherein the misregistration detection unit determines the presence / absence of the substrate to be processed and the misregistration state based on the detected pressure from each of the pressure sensors. The substrate holding mechanism according to claim 2, wherein the pressure detection holes formed in the four corners communicate with the plurality of gas holes through a communication path. The substrate holding mechanism according to claim 2, wherein the pressure detection holes formed in the four corners are connected to the gas supply source via the flow rate regulator. The said pressure detection hole contains the other pressure detection hole formed separately from what was each formed in the four corner | angular parts of the said board | substrate holding surface, The Claim 3 characterized by the above-mentioned. Substrate holding mechanism. Detecting a displacement of the substrate to be processed based on a detected pressure from a pressure detecting hole formed in the four corners;
The substrate holding mechanism according to claim 8, wherein the gas flow rate is adjusted by the flow rate regulator based on a detected pressure from the other pressure detection hole. The substrate holding mechanism according to claim 1, wherein a channel piece having a plurality of holes is fitted in the pressure detection hole. A substrate misalignment detection method in a substrate holding mechanism for mounting and holding a rectangular substrate to be processed in a space where plasma is generated,
The substrate holding mechanism is
A rectangular mounting table for mounting and holding the substrate to be processed;
A gas flow path for supplying gas from a gas supply source between the mounting table and the substrate to be processed held on the substrate holding surface;
A plurality of gas holes formed on the substrate holding surface of the mounting table for guiding the gas from the gas flow path onto the substrate holding surface;
A plurality of pressure detection holes which are formed outside the gas hole forming region on the substrate holding surface and detect pressure applied to the back surface of the substrate to be processed;
A pressure sensor connected to the plurality of pressure detection holes;
A flow rate regulator for regulating the gas flow rate from the gas supply source,
A substrate misalignment detection method characterized by detecting misalignment of the substrate to be processed based on a detected pressure from the pressure sensor and adjusting a gas flow rate by the flow rate regulator. The plurality of pressure detection holes are respectively formed at four corners of the rectangular substrate holding surface, and the pressure sensors are a plurality of pressure sensors respectively connected to the pressure detection holes,
The substrate positional deviation detection method according to claim 11, wherein the presence / absence of the substrate to be processed and the positional deviation state are determined based on a detected pressure from each pressure sensor. Whether or not the substrate to be processed is misaligned is determined based on whether or not all of the detected pressures at the four corners detected by the pressure sensors have reached a set pressure.
The substrate positional deviation detection method according to claim 12, wherein when any of the detected pressures does not reach a set pressure, the presence / absence of the substrate to be processed and the positional deviation state are determined. In determining the presence / absence of the substrate to be processed and the misalignment state,
If the detected pressures of the four corners detected by the pressure sensors are balanced and have not reached the set pressure, the substrate to be processed is not on the mounting table or the substrate to be processed is not present. It is determined that the processing substrate is in an adsorption failure state,
14. The method according to claim 13, wherein when any of the detected pressures at the four corners is unbalanced, it is determined that the substrate to be processed on the mounting table is in a position shift state. Detection method for substrate misalignment. If an imbalance has occurred in any of the detected pressures at the four corners, it is determined that the substrate parallel displacement in one direction is an imbalance between the two parallel corners of the four corners. ,
If there is an imbalance between the three corners of the four corners and the remaining one corner, it is determined that the substrate is parallelly displaced in two directions.
The substrate positional deviation detection method according to claim 14, wherein if the diagonal two of the four corners are imbalanced, it is determined that the substrate is skewed. A plasma processing apparatus for introducing a processing gas into a processing chamber and generating a plasma of the processing gas, thereby performing a predetermined plasma processing on a substrate to be processed made of an insulator mounted and held on a mounting table in the processing chamber. And
A gas flow path for supplying gas from a gas supply source between the mounting table and the substrate to be processed held on the substrate holding surface;
A plurality of gas holes formed on the substrate holding surface of the mounting table for guiding the gas from the gas flow path onto the substrate holding surface;
A plurality of pressure detection holes which are formed outside the gas hole forming region on the substrate holding surface and detect pressure applied to the back surface of the substrate to be processed;
A pressure sensor connected to the plurality of pressure detection holes;
A displacement detection means for detecting a displacement of the substrate to be processed based on a detected pressure from the pressure sensor;
A plasma processing apparatus comprising:

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