Lift pin position detecting method and substrate processing apparatus

Abstract

To easily teach a standby position of a lift pin.SOLUTION: The lift pin is disposed in a pin hole opened in a placing surface of a placing table on which a substrate is placed, extends in a vertical direction, and has a thin shaft portion and a thick shaft portion provided above the thin shaft portion and having a diameter larger than that of the thin shaft portion, a first step is formed at a location where the thick shaft portion changes to the thin shaft portion, the lift pin is connected to a driving mechanism that moves the lift pin in the vertical direction, and the pin hole is drilled in the vertical direction and has a large diameter portion and a small diameter portion provided below the large diameter portion and having a diameter smaller than that of the large diameter portion, A second step is formed at a location where the large diameter portion changes to the small diameter portion, and the contact between the first step and the second step when the lift pin is further lowered after being raised is detected based on the index of the load of the drive mechanism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a lift pin position detection method and a substrate processing apparatus. [Background technology]

[0002] In a substrate processing apparatus, when a substrate such as a wafer or glass substrate is subjected to various processes, the substrate is placed on a mounting table inside a processing chamber. This mounting table may also serve as a lower electrode. When the substrate is transferred into or out of the processing chamber, the substrate is lifted and separated from the mounting table by protruding multiple lift pins in the vertical direction from the surface of the mounting table (hereinafter referred to as the "mounting surface").

[0003] When performing various processes on a substrate, each lift pin is housed in a pin hole drilled in the mounting table. However, since the position of the upper end of the lift pin affects the processing results, it is necessary to teach in advance the position where the upper end of the lift pin will be waiting during processing. The position where the upper end of the lift pin will be waiting (hereinafter referred to as the "lift pin waiting position") is a position lowered a predetermined distance from the mounting surface depending on the processing content. Therefore, to teach the lift pin waiting position, it is first necessary to obtain the position of the lift pin when its upper end is aligned with the mounting surface (hereinafter referred to as the "mounting surface position"). Then, the lift pin is lowered a predetermined distance from the mounting surface position to move the lift pin to the waiting position.

[0004] A conventional method for obtaining the placement surface position is to use a weight. Specifically, after the weight is placed on the placement surface so as to cover the pin hole, the lift pin is raised, and the position of the lift pin when its upper end abuts the weight is regarded as the placement surface position.

[0005] At this time, whether or not the top end of the lift pin has come into contact with the weight is determined using an accumulation pulse, which is an index corresponding to the difference between the ideal (calculated) lift pin position for control purposes and the actual position of the lift pin. Note that, hereinafter, the ideal lift pin position for control purposes will be referred to as the "controlled ideal position" of the lift pin, and the actual position of the lift pin will be referred to as the "actual position" of the lift pin.

[0006] After the top of the lift pin contacts the weight, the absolute value of the accumulation pulse increases as the lift pin's ideal control position and actual position deviate from each other while the weight is not being lifted. Then, when the lift pin begins to lift the weight, the deviation between the ideal control position and actual position decreases, and the absolute value of the accumulation pulse decreases.

[0007] That is, after the upper end of the lift pin contacts the spindle, the absolute value of the accumulated pulse increases and then decreases. Therefore, a threshold is set between the point where the absolute value of the accumulated pulse increases and the point where the absolute value of the accumulated pulse decreases, and it is determined that the upper end of the lift pin contacts the spindle when the accumulated pulse reaches the threshold (see, for example, Patent Document 1). Then, the position of the lift pin at this time is acquired as the mounting surface position. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-50534 Summary of the Invention [Problem to be solved by the invention]

[0009] The technology according to the present disclosure makes it easy to teach the standby position of the lift pins. [Means for solving the problem]

[0010] One aspect of the technology according to the present disclosure is a method for detecting the position of a lift pin that is disposed in a pin hole that opens into a mounting surface of a mounting table that is disposed inside a processing chamber and that mounts a substrate thereon, and that moves up and down in the pin hole to protrude and retract relative to the mounting surface, wherein the lift pin extends in the up and down direction and has a thin shaft portion and a thick shaft portion that is disposed above the thin shaft portion and has a larger diameter than the thin shaft portion, a first step is formed at a location where the thick shaft portion changes into the thin shaft portion, and the lift pin is moved up and down. the pin hole is drilled in the vertical direction and has a large diameter portion and a small diameter portion that is located below the large diameter portion and has a diameter smaller than the large diameter portion, and a second step is formed at the location where the large diameter portion changes to the small diameter portion, and the lift pin raising and lowering process includes raising the lift pin and then further lowering it to bring the first step into contact with the second step, and a contact detection process includes detecting the contact between the first step and the second step during the lift pin raising and lowering process based on an index of the load of the drive mechanism. [Effects of the Invention]

[0011] According to the technology of the present disclosure, it is possible to easily teach the standby position of the lift pin. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view schematically illustrating a configuration of a substrate processing apparatus according to an embodiment of the technology disclosed herein. [Figure 2] FIG. 2 is a block diagram showing the configuration of a drive unit of the lift pin device. [Figure 3] FIG. 2 is a cross-sectional view showing in detail the configuration around a lift pin in the lift pin device. [Figure 4] 10A to 10C are process diagrams illustrating a method for detecting the positions of lift pins and a method for teaching the standby positions of lift pins, which are performed during maintenance of the substrate processing apparatus. [Figure 5] 10A to 10C are process diagrams illustrating a method for detecting the positions of lift pins and a method for teaching the standby positions of lift pins, which are performed during maintenance of the substrate processing apparatus. [Figure 6] 6A and 6B are diagrams showing transitions in the position of the lift pins in the method of detecting the position of the lift pins and the method of teaching the standby position of the lift pins in FIGS. 4 and 5. FIG. [Figure 7] 10 is a graph showing the change in the accumulation pulse when the pin-side step of the lift pin abuts against the hole-side step of the pin hole. [Figure 8] 10A to 10C are process diagrams illustrating a method for detecting the position of the lift pins and a method for teaching the standby position of the lift pins, which are executed after a change over time. [Figure 9] 10A to 10C are process diagrams illustrating a method for detecting the position of the lift pins and a method for teaching the standby position of the lift pins, which are executed after a change over time. [Figure 10] 10 is a graph showing the change in torque when a pin-side step of a lift pin abuts against a hole-side step of a pin hole. DETAILED DESCRIPTION OF THE INVENTION

[0013] However, the technology described in Patent Document 1 requires the use of a weight, which requires time for setting and retrieving the weight. Furthermore, since the position and extension of the lift pins are affected by pressure and heat, when acquiring the placement surface position, it is preferable to reduce the pressure inside the processing vessel and heat the placement table after installing the weight, just as when processing the substrate. In this case, it takes a long time, for example, several hours, for the pressure inside the processing vessel and the temperature of the placement table to settle. Therefore, it is difficult to easily acquire the placement surface position.

[0014] However, when processing is repeated in a substrate processing apparatus, the relative positional relationship between the lift pins and the mounting surface may change slightly over time, and even if the position of the lift pins is aligned with the position of the mounting surface, the upper ends of the lift pins may no longer coincide with the mounting surface.

[0015] Therefore, after the relative positional relationship between the lift pins and the support surface has changed, it is preferable to acquire the support surface position again and calibrate the support surface position, but as described above, it is difficult to acquire the support surface position using a weight. As a result, if the calibration of the support surface position is not performed again, even if the lift pin position is adjusted to the support surface position, the upper end of the lift pin will not coincide with the support surface, making it difficult to teach the standby position of the lift pin.

[0016] In response to this, the technology according to the present disclosure acquires a reference position for teaching the standby position of the lift pin without using a weight.

[0017] An embodiment of the technology according to the present disclosure will now be described with reference to the drawings, in which: Fig. 1 is a cross-sectional view schematically showing the configuration of a substrate processing apparatus according to the present embodiment.

[0018] The substrate processing apparatus 10 shown in FIG. 1 is a capacitively coupled parallel-plate plasma etching apparatus that performs plasma etching on, for example, rectangular glass substrates G for flat panel displays (FPDs). The substrate processing apparatus 10 includes a rectangular cylindrical processing chamber 11 made of aluminum with an anodized (alumite) surface. The processing chamber 11 is composed of a bottom wall 12 and four side walls 13, and a lid 14 is attached to the top of the processing chamber 11. The lid 14 is configured to be openable and closable by an opening / closing mechanism (not shown). When the lid 14 is closed, the joints between the lid 14 and each side wall 13 are sealed with sealing members (not shown), keeping the interior of the processing chamber 11 airtight. A mounting table 15 on which the rectangular glass substrate G is placed is provided at the bottom inside the processing chamber 11. Heaters and chillers (none of which are shown) are embedded in each side wall 13, the lid 14, and the mounting table 15.

[0019] The mounting table 15 includes a base 16 made of a conductive material such as aluminum or stainless steel (SUS), and an insulating member (not shown) covering the base 16. A high-frequency bias power supply (neither of which is shown) is connected to the base 16 via a power feeder or a matching box, and the base 16 also functions as a lower electrode. The mounting table 15 also includes an electrostatic chuck 17 made of a dielectric material and disposed on the base 16. An electrode 18 is embedded in the electrostatic chuck 17, and applying a DC voltage from a DC power supply 19 to the electrode 18 via a power feeder 20 electrostatically attracts the glass substrate G to the mounting table 15 by, for example, Coulomb force. The mounting table 15 also includes a back-cooling mechanism (not shown) that performs gas heat transfer between the mounting table 15 and the glass substrate G. The back-cooling mechanism performs gas heat transfer by supplying and filling a back-cooling gas, such as helium gas, from a back-cooling gas supply unit through a back-cooling path (neither of which is shown) into the space formed between the mounting surface of the mounting table 15 and the glass substrate G.

[0020] The mounting table 15 also has a plurality of lift pin devices 21. For example, a substrate processing apparatus 10 that performs an etching process on a sixth-generation glass substrate G has 16 lift pin devices 21. Each lift pin device 21 has lift pins 23 that are movable in the vertical direction in the figure, and a drive unit 24 (drive mechanism) that is connected to the lift pins 23 and moves the lift pins 23 in the vertical direction.

[0021] Each lift pin 23 extends in the vertical direction, and is inserted into a pin hole 22 bored in the base material 16 of the mounting table 15 in the vertical direction corresponding to each lift pin 23, thereby being positioned in each pin hole 22. Each pin hole 22 opens into a mounting surface of the mounting table 15 on which the glass substrate G is to be placed, and each lift pin 23 is protruded and retracted relative to the mounting surface of the mounting table 15 by each drive unit 24.

[0022] In each lift pin device 21, when the lift pins 23 move upward, their tips protrude from the mounting surface of the mounting table 15, thereby lifting the glass substrate G and separating it from the mounting surface of the mounting table 15. In this embodiment, the mounting surface of the mounting table 15 coincides with the surface of the electrostatic chuck 17.

[0023] A showerhead 25 serving as an upper electrode is provided above the mounting table 15. The showerhead 25 is attached to the lid 14 on the top of the processing chamber 11. The showerhead 25 is a hollow plate-like member, and a gas diffusion space 26 is provided inside the showerhead 25. A plurality of gas discharge holes 27 are formed on the bottom surface of the showerhead 25, through which an etching gas serving as a processing gas is discharged. The showerhead 25 is grounded, and together with the mounting table 15, constitute a pair of parallel plate electrodes.

[0024] A gas inlet 28 is provided near the center of the upper part of the shower head 25. A gas supply pipe 29 for supplying a processing gas is connected to the gas inlet 28, and the gas supply pipe 29 connects a gas supply source 30 for supplying, for example, an etching gas as the processing gas to the gas inlet 28.

[0025] A plurality of exhaust openings 31 serving as through-openings are formed in the bottom wall 12 near the four corners of the interior of the processing vessel 11. An exhaust pipe 32 is connected to each exhaust opening 31, and an exhaust device 33 equipped with a vacuum pump such as a turbomolecular pump is connected to the exhaust pipe 32. The exhaust device 33 evacuates the interior of the processing vessel 11 to a reduced pressure atmosphere required for etching processing.

[0026] Furthermore, a loading / unloading port is provided in sidewall 13 of processing chamber 11, and loading / unloading port is opened and closed by a gate valve 35. Glass substrates G are loaded into and unloaded from processing chamber 11 through loading / unloading port .

[0027] The substrate processing apparatus 10 has a control unit 36, and each component of the substrate processing apparatus 10 is connected to the control unit 36. The control unit 36 ​​is, for example, a module controller, and controls the operation of each component by transmitting and receiving control signals to and from each component. For example, when performing an etching process, the control unit 36 ​​adjusts the temperatures of each side wall 13, lid 14, and mounting table 15 using each heater and each chiller in accordance with a recipe or the like.

[0028] 2 is a block diagram showing the configuration of the drive unit 24 of the lift pin device 21. The drive unit 24 is a servo motor having a pulse generating unit 37, a motor 38, a servo amplifier 39 serving as a motor driver, and an encoder 40. The servo amplifier 39 is also provided with a deviation counter 41 and a D / A conversion unit (not shown).

[0029] The pulse generating unit 37 is, for example, a programmable logic controller (PLC). The pulse generating unit 37 generates a command pulse according to the speed at which the lift pins 23 are moved (hereinafter referred to as the “set speed”) set by the control unit 36, and inputs the command pulse to the servo amplifier 39.

[0030] The servo amplifier 39 outputs a command signal to the motor 38 to drive the motor 38 in response to the command pulse, and receives a feedback signal generated by the driving of the motor 38 to control the torque, rotation speed, position, etc. of the motor 38. The servo amplifier 39 also outputs various parameters to the control unit 36 ​​based on the command signal and feedback signal.

[0031] The motor 38 is connected to the lift pins 23 and rotates at a rotational speed and torque according to a command signal from a servo amplifier 39, thereby driving the lift pins 23 in the vertical direction. The encoder 40 generates a feedback pulse proportional to the actual rotation speed of the motor 38 and feeds this feedback pulse back to the servo amplifier 39.

[0032] In the drive unit 24, command pulses generated according to the set speed are integrated by a deviation counter 41 of a servo amplifier 39. The integrated value of these command pulses is then converted by the servo amplifier 39 into a DC analog voltage to rotate the motor 38, thereby driving the lift pins 23 up and down. At this time, as the motor 38 rotates, an encoder 40 generates a feedback pulse proportional to the rotation speed of the motor 38. This feedback pulse is fed back to the servo amplifier 39, and the integrated value of the feedback pulse is subtracted from the integrated value of the command pulses of the deviation counter 41.

[0033] Because command pulses continue to be generated while the lift pins 23 are being moved at the set speed, the integrated value of the command pulses corresponds to the ideal (calculated) position of the lift pins 23 in terms of control (corresponding to the above-mentioned "controlled ideal position"), which is the set speed multiplied by the driving time of the motor 38. In addition, because the feedback pulses are proportional to the actual number of rotations of the motor 38, the integrated value of the feedback pulses indicates the actual movement distance of the lift pins 23 caused by the motor 38, and corresponds to the actual position of the lift pins 23 (corresponding to the above-mentioned "actual position"). The encoder value is the integrated value of the feedback pulses converted into the actual movement distance of the lift pins 23.

[0034] Therefore, the pulses obtained by subtracting the integrated value of the feedback pulses from the integrated value of the command pulses of the deviation counter 41 correspond to the difference between the ideal control position and the actual position, and in this embodiment, this difference is defined as the "accumulation pulses." For example, if the movement of the lift pin 23 is hindered by an obstacle, the actual position deviates from the ideal control position, increasing the difference between the ideal control position and the actual position, and therefore the absolute value of the accumulation pulses increases. In other words, the accumulation pulses are also an indicator of the load on the motor 38.

[0035] The drive unit 24 calculates these accumulating pulses as needed and outputs them to the control unit 36, and at the same time, outputs the time when the accumulating pulses were calculated, the torque of the motor 38, and the encoder value to the control unit 36. As described above, since the accumulating pulses are calculated as needed, the accumulating pulses are discrete values, and since the accumulating pulses are calculated by subtracting the integrated value of the feedback pulses from the integrated value of the command pulses, the unit of the accumulating pulses is the number of pulses.

[0036] 3 is a cross-sectional view showing in detail the configuration around lift pin 23 in lift pin device 21. In Fig. 3, lift pin 23 is made of a cylindrical member and has thin shaft portion 42 and thick shaft portion 43 that is provided above thin shaft portion 42 and has a larger diameter than thin shaft portion 42, and a pin-side step 44 (first step) is formed at the location where thick shaft portion 43 changes into thin shaft portion 42. Note that although lift pin 23 is made of a solid body in this embodiment, it may also be made of a hollow body, for example.

[0037] Furthermore, a cylindrical member 45 is inserted into the pin hole 22. Because the inner diameter of the cylindrical member 45 is smaller than the inner diameter of the pin hole 22, the pin hole 22 above the cylindrical member 45 forms a large diameter portion, and the cylindrical member 45 forms a small diameter portion. That is, in the pin hole 22, a small diameter portion is provided below the large diameter portion. Furthermore, the portion where the large diameter portion changes to the small diameter portion, i.e., the upper end of the cylindrical member 45, forms a hole-side step 46 (second step). In the lift pin device 21, the positional relationship between the thin shaft portion 42 and the cylindrical member 45 is specified so that the thin shaft portion 42 is inserted into the cylindrical member 45 when the lift pin 23 is inserted into the pin hole 22.

[0038] A cylindrical fixing member 47 is disposed coaxially with the cylindrical member 45 on the outer periphery of the cylindrical member 45 so as to surround the cylindrical member 45. The fixing member 47 is fixed to the mounting table 15. A male thread 48 is formed on the outer periphery of the cylindrical member 45, and a female thread 49 is formed on the inner periphery of the fixing member 47. The male thread 48 of the cylindrical member 45 is threadedly engaged with the female thread 49 of the fixing member 47. By rotating the cylindrical member 45 about its central axis relative to the fixing member 47, the fixing member 47, and therefore the cylindrical member 45, can be moved up and down relative to the mounting table 15. Because the fixing member 47, with which the cylindrical member 45 is threaded, is fixed to the mounting table 15, the cylindrical member 45 will not move up and down relative to the mounting table 15 unless the cylindrical member 45 is rotated about its central axis. The lift pins 23, the cylindrical member 45, and the fixing member 47 are made of metal, such as aluminum or stainless steel.

[0039] The lift pin device 21 also includes a coupling mechanism 50 that couples the lift pins 23 and the drive unit 24, and a support member 51 that supports the coupling mechanism 50. The coupling mechanism 50 is composed of multiple parts and has a generally cylindrical shape as a whole. The support member 51 is generally cylindrical, fixed to the mounting table 15, and houses the coupling mechanism 50. A linear bushing 52 is disposed between the coupling mechanism 50 and the support member 51. The linear bushing 52 is fixed to the inner periphery of the support member 51 and guides the coupling mechanism 50, which moves up and down together with the lift pins 23. In the lift pin device 21, the pin holes 22, lift pins 23, coupling mechanism 50, and support member 51 are coaxially disposed.

[0040] Furthermore, in the lift pin device 21, in order to smoothly move the lift pins 23 in the vertical direction, the diameter of the thin shaft portions 42 of the lift pins 23 is set to be slightly smaller than the inner diameter of the cylindrical member 45. Therefore, a minute gap is formed between the thin shaft portions 42 of the lift pins 23 and the inner periphery of the cylindrical member 45.

[0041] Incidentally, a bellows (not shown) is provided between the drive unit 24 and the mounting table 15, and the internal space of the support member 51 containing the connecting mechanism 50 is isolated from the atmospheric space in which the drive unit 24 is disposed. However, a small amount of atmospheric air permeates from the sealing surface of the bellows into the internal space of the support member 51, and atmospheric air remains in the internal space of the support member 51. This internal space may be connected to a space filled with back-cooling gas formed between the mounting surface of the mounting table 15 and the glass substrate G via a minute space between the thin shaft portion 42 of the lift pin 23 and the inner periphery of the cylindrical member 45.

[0042] Therefore, in the lift pin device 21, a sealing member, for example, an O-ring 53, is placed in the pin hole 22 so as to seal the minute gap between the thin shaft portion 42 and the inner circumference of the cylindrical member 45. This airtightly seals the minute gap between the thin shaft portion 42 and the inner circumference of the cylindrical member 45 from the internal space of the support member 51, where air remains. The O-ring 53 is made of an elastomer material, for example, any of various heat-resistant rubber materials such as silicone rubber or fluororubber.

[0043] In the lift pin device 21, when the lift pin 23 is moved downward, the pin-side step 44 of the lift pin 23 abuts against the hole-side step 46 of the pin hole 22 (the upper end of the cylindrical member 45). As described above, the cylindrical member 45 does not move up or down relative to the mounting table 15 unless it is rotated around its central axis, and the cylindrical member 45 is fixed to the mounting table 15 via a fixing member 47. Therefore, the relative positional relationship between the cylindrical member 45 and the mounting table 15 does not change over time. That is, the position where the pin-side step 44 abuts against the hole-side step 46 does not change over time relative to the mounting table 15 and remains unchanged. Therefore, in this embodiment, the position where the pin-side step 44 abuts against the hole-side step 46 is used as a reference position for teaching the standby position of the lift pin 23.

[0044] 4 and 5 are process diagrams illustrating a method for detecting the positions of the lift pins 23 and a method for teaching the standby positions of the lift pins 23, which are performed during maintenance of the substrate processing apparatus 10. The methods for detecting the positions of the lift pins 23 and teaching the standby positions of the lift pins 23 shown in FIGS. 4 and 5 are performed by the control unit 36. Maintenance here refers to, for example, replacing components of the substrate processing apparatus 10, such as the electrostatic chuck 17 and the lift pin device 21, with the lid 14 of the processing vessel 11 open to the atmosphere. During maintenance, the heaters of the side walls 13, the lid 14, and the mounting table 15 are not energized, and the side walls 13, the lid 14, and the mounting table 15 are not heated. Furthermore, the chillers of the side walls 13, the lid 14, and the mounting table 15 are not operated. 4 and 5 are performed in a state where the processing vessel 11 is open to the atmosphere and where there is no temperature control of the side walls 13, the lid 14, or the mounting table 15. FIG. 6 is a diagram showing the transition of the position of the lift pins 23 in the method for detecting the position of the lift pins 23 and the method for teaching the standby position of the lift pins 23 in the method for detecting the position of the lift pins 23 and the method for teaching the standby position of the lift pins 23 in FIGS.

[0045] First, the driver 24 sets the position of the upper end of the lift pin 23 to a start position inside the pin hole 22 (FIG. 4(A)). The start position here is a position that is lowered by a predetermined first distance, for example, 200 μm, from the mounting surface of the mounting table 15.

[0046] Next, the lift pins 23 are raised by the drive unit 24 until the positions of the upper ends of the lift pins 23 reach an ascent stop position (FIG. 4(B), step 1 in FIG. 6). The ascent stop position here is a position raised by a predetermined second distance, for example, 500 μm, from the mounting surface of the mounting table 15. Thereafter, while the lift pins 23 move up and down, the drive unit 24 continues to output the accumulation pulse, the torque of the motor 38, and the encoder value to the control unit 36 ​​as a data set.

[0047] Next, after specifying the amount by which the lift pins 23 can be lowered, the lift pins 23 are lowered by the driving unit 24 (step 2 in FIG. 6). The amount by which the lift pins 23 can be lowered is set to, for example, 1000 μm. Note that steps 1 and 2 in FIG. 6 correspond to the lift pin raising and lowering step.

[0048] Then, as the lift pin 23 descends in the pin hole 22, the pin-side step 44 of the lift pin 23 abuts against the hole-side step 46 of the pin hole 22 (the upper end of the cylindrical member 45) (FIG. 4(C)). After that, the lift pin 23 cannot descend, so a difference occurs between the ideal control position of the lift pin 23 and the actual position of the lift pin 23, and the absolute value of the accumulating pulse increases along with the change in the encoder value corresponding to the actual movement distance of the lift pin 23, as shown in FIG. 7. In this embodiment, the midpoint between the rising edge and the extreme value (maximum value in the figure) of the accumulating pulse is set as a threshold, and when the accumulating pulse reaches this threshold, the abutment of the pin-side step 44 and the hole-side step 46 is detected (abutment detection process).

[0049] Next, with the pin-side step 44 of the lift pin 23 in contact with the hole-side step 46 of the pin hole 22, the dial gauge 54 is placed on the mounting surface of the mounting table 15. The scale of the dial gauge 54 is adjusted so that the measured value becomes "0" when the position of the lower end of the downwardly extending measuring probe 55 coincides with the position of the mounting surface of the mounting table 15. Then, the measuring probe 55 is inserted into the pin hole 22, and the lower end of the measuring probe 55 is brought into contact with the upper end of the lift pin 23 (FIG. 5(A)).

[0050] Next, the drive unit 24 raises the lift pin 23 from the position of the lift pin 23 when the contact between the pin-side step 44 and the hole-side step 46 is detected until the scale of the dial gauge 54 reaches "0" (FIG. 5(B), step 3 in FIG. 6). Here, the amount of movement of the lift pin 23 from the state where the pin-side step 44 contacts the hole-side step 46 until the scale of the dial gauge 54 reaches "0" is acquired as a correction value. This correction value corresponds to the distance from the upper end of the lift pin 23 to the mounting surface of the mounting table 15 when the pin-side step 44 contacts the hole-side step 46.

[0051] Next, the dial gauge 54 is removed from the mounting surface of the mounting table 15, and the lift pins 23 are lowered by a predetermined adjustment value, for example, 50 μm, using the driving unit 24 (FIG. 5(C), step 4 in FIG. 6). That is, the positions of the upper ends of the lift pins 23 are lowered by the adjustment value from the position on the mounting surface of the mounting table 15. This adjustment value corresponds to a distance at which the upper ends of the lift pins 23 no longer affect the etching process performed on the glass substrate G placed on the mounting surface of the mounting table 15. Then, the control unit 36 ​​instructs itself on itself the position of the lift pins 23 after they have been lowered by the adjustment value as the standby position of the lift pins 23. Note that the "position of the lift pins 23" in this embodiment refers to any position on the lift pins 23, and may be any position that can be easily used as a guide when adjusting the position of the lift pins 23, for example, the position of the upper ends of the lift pins 23.

[0052] 4 and 5 to teach the standby positions of the lift pins 23, the lid 14 of the processing vessel 11 is closed, and the interior of the processing vessel 11 is evacuated to reduce the pressure, and an etching process is performed. At this time, the control unit 36 ​​controls the drive unit 24 to move the lift pins 23 to the taught standby positions. However, repeated etching processes can cause subtle changes in the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 due to changes over time. As a result, even if the lift pins 23 are moved to the taught standby positions, the distance from the upper ends of the lift pins 23 to the mounting surface of the mounting table 15 may change from the adjusted value, which could affect the etching process performed on the glass substrate G. Therefore, after changes over time occur, it is necessary to re-teach the standby positions of the lift pins 23 so that the distance from the upper ends of the lift pins 23 to the mounting surface of the mounting table 15 does not change from the adjusted value.

[0053] 8 and 9 are process diagrams illustrating a method for detecting the positions of the lift pins 23 and a method for teaching the standby positions of the lift pins 23, which are executed after changes over time. The methods for detecting the positions of the lift pins 23 and teaching the standby positions of the lift pins 23 shown in FIGS. 8 and 9 are also executed by the control unit 36. For example, whether the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 has changed over time is determined based on the cumulative time of the etching process after previously checking the correlation between the cumulative time of the etching process and the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15. The methods for detecting the positions of the lift pins 23 and teaching the standby positions of the lift pins 23 shown in FIGS. 8 and 9 are executed in an idle (standby) state between one etching process and the next, and in a state in which the processing chamber 11 is not open to the atmosphere and is depressurized. The method of detecting the position of the lift pins 23 and the method of teaching the standby position of the lift pins 23 shown in Figures 8 and 9 may be performed in an idle state when the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 has not changed over time.

[0054] First, the driver 24 sets the position of the upper end of the lift pin 23 to a start position inside the pin hole 22 (FIG. 8(A)). Then, the driver 24 raises the lift pin 23 until the position of the upper end of the lift pin 23 reaches the lift stop position (FIG. 8(B)).

[0055] Next, after specifying the amount by which the lift pin 23 can be lowered, the lift pin 23 is lowered by the drive unit 24. Then, while the lift pin 23 is lowering in the pin hole 22, the pin-side step 44 of the lift pin 23 abuts against the hole-side step 46 (the upper end of the cylindrical member 45) of the pin hole 22 (FIG. 8(C)). Then, when the accumulated pulse reaches the threshold value, the abutment between the pin-side step 44 and the hole-side step 46 is detected.

[0056] Next, the drive unit 24 raises the lift pin 23 by a correction value from the position of the lift pin 23 when the contact between the pin-side step 44 and the hole-side step 46 is detected. Here, as described above, the position where the pin-side step 44 contacts the hole-side step 46 does not change with time relative to the mounting table 15 and remains unchanged. Therefore, the distance from the position where the pin-side step 44 contacts the hole-side step 46 (the position of the upper end of the cylindrical member 45) to the mounting surface of the mounting table 15 remains unchanged. Furthermore, because the pin-side step 44 and the upper end of the lift pin 23 are formed on the same lift pin 23, the distance from the pin-side step 44 to the upper end of the lift pin 23 also remains unchanged with time. Therefore, even if the relative positional relationship between the lift pin 23 and the mounting surface of the mounting table 15 changes over time, the distance from the upper end of the lift pin 23 to the mounting surface of the mounting table 15 when the pin-side step 44 abuts against the hole-side step 46 remains unchanged. As described above, the correction value corresponds to the distance from the upper end of the lift pin 23 to the mounting surface of the mounting table 15 when the pin-side step 44 abuts against the hole-side step 46. As a result, if the lift pin 23 is raised by the correction value from the position of the lift pin 23 when the abutment between the pin-side step 44 and the hole-side step 46 is detected, the position of the upper end of the lift pin 23 will coincide with the position of the mounting surface of the mounting table 15, even if the above-mentioned change over time occurs. In other words, the position of the upper end of the lift pin 23 can be coincident with the position of the mounting surface of the mounting table 15 without using the dial gauge 54 or a weight to block the pin hole 22 ( FIG. 9(A) ).

[0057] Next, the lift pins 23, whose upper ends are now aligned with the mounting surface of the mounting table 15, are lowered by the adjustment value by the drive unit 24 (FIG. 9(B)). That is, the upper ends of the lift pins 23 are lowered by the adjustment value from the mounting surface of the mounting table 15. Then, the control unit 36 ​​instructs itself on the position of the lift pins 23 after being lowered by the adjustment value as the standby position of the lift pins 23.

[0058] In this embodiment, the correction value acquired when the processing vessel 11 is open to the atmosphere is used to teach the standby position of the lift pins 23 when the processing vessel 11 is depressurized. Therefore, in order to confirm the effect of the pressure in the processing vessel 11 on the correction value, the applicant confirmed the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 when the lift pins 23 were raised using the correction value when the processing vessel 11 was open to the atmosphere and when the processing vessel 11 was depressurized.

[0059] 4(A) to 5(B) and acquired the correction values ​​while the processing vessel 11 was open to the atmosphere. Naturally, when the correction values ​​were acquired, the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 was 0 μm (first time in the atmosphere).

[0060] Thereafter, while maintaining the processing vessel 11 in an open state to the atmosphere, the applicant lowered the lift pins 23 to bring the pin-side steps 44 into contact with the hole-side steps 46. Furthermore, the applicant raised the lift pins 23 by a correction value from the position of the lift pins 23 when the contact between the pin-side steps 44 and the hole-side steps 46 was detected. Then, the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 at this time was measured with the dial gauge 54 (second time in atmosphere). Next, while maintaining the processing vessel 11 in an open state to the atmosphere, the applicant repeated the same raising and lowering of the lift pins 23 and the measurement of the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 as in the second time in atmosphere (third time in atmosphere).

[0061] Furthermore, the applicant measured the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 while the processing vessel 11 was open to the atmosphere, and then closed the lid 14 of the processing vessel 11 with the dial gauge 54 still placed on the mounting surface of the mounting table 15 to seal the processing vessel 11. Then, after evacuating the interior of the processing vessel 11 to reduce the pressure, the applicant lowered the lift pins 23 to bring the pin-side step 44 into contact with the hole-side step 46. Furthermore, the applicant raised the lift pins 23 by a correction value from the position of the lift pins 23 when the contact between the pin-side step 44 and the hole-side step 46 was detected. Thereafter, the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 at this time was measured with the dial gauge 54 (first vacuum).

[0062] Thereafter, while maintaining the reduced pressure state of the processing vessel 11, the applicant again lowered the lift pins 23 to bring the pin-side steps 44 into contact with the hole-side steps 46. Furthermore, the applicant raised the lift pins 23 by a correction value from the position of the lift pins 23 when the contact between the pin-side steps 44 and the hole-side steps 46 was detected. The deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 at this time was also measured with the dial gauge 54 (second vacuum test). Next, while maintaining the reduced pressure state of the processing vessel 11, the applicant repeatedly raised and lowered the lift pins 23 and measured the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 in the same manner as in the second vacuum test (third vacuum test).

[0063] The applicant then compiled the measurement results of the misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 as shown in Table 1 below. These misalignment measurements were performed at four lift pin devices 21, and the measurement results for each lift pin device 21 are indicated by "dial gauge 1," "dial gauge 2," "dial gauge 3," and "dial gauge 4" in Table 1. Note that these misalignment measurements were performed consecutively as described above, and therefore the measurements were taken when the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 had not changed over time.

[0064] When measuring the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15, the temperatures of the chillers for the side walls 13, the lid 14, and the mounting table 15 were set to 25°C. When the processing vessel 11 was open to the atmosphere, the temperatures of the side walls 13 were 34.9°C, the temperature of the lid 14 was 31.0°C, and the temperature of the mounting table 15 was 36.2°C. When the processing vessel 11 was depressurized, the temperatures of the side walls 13 were 34.0°C, the temperature of the lid 14 was 30.2°C, and the temperature of the mounting table 15 was 36.5°C.

[0065] [Table 1]

[0066] As shown in Table 1, when the processing vessel 11 was open to the atmosphere, even when the measurement of the misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 was repeated, the maximum absolute value of the misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 remained at 7 μm. In other words, it was found that when the processing vessel 11 was open to the atmosphere, it was possible to reuse the correction value once obtained, as long as the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 did not change over time.

[0067] Furthermore, when the processing vessel 11 was depressurized, repeated measurements of the misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 revealed that the maximum absolute value of the misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 was 68 μm. In other words, there was no significant misalignment between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15. Therefore, it was found that even when the processing vessel 11 was depressurized, it was possible to reuse the correction value obtained when the processing vessel 11 was open to the atmosphere, as long as there was no change over time in the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15.

[0068] As shown in the measurement results of "Dial Gauge 4" in Table 1 when the processing vessel 11 is depressurized, the absolute value of the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 decreases with repeated measurements. The applicant has hypothesized the mechanism described below as the reason why the absolute value of the deviation decreases with repeated measurements. That is, even when the processing vessel 11 is depressurized, in the lift pin device 21, air remains in the internal space of the support member 51 below the O-ring 53. Therefore, the pressure difference causes some deviation in the positions of components such as the cylindrical member 45 near the O-ring 53. However, when the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 is repeatedly measured, the pin-side step 44 and the hole-side step 46 repeatedly come into contact with each other, pressing the cylindrical member 45 toward the O-ring 53. Therefore, when this contact is repeated, O-ring 53 pressed by cylindrical member 45 undergoes slight deformation, and the internal space of support member 51 and the interior of processing vessel 11 may become connected via the minute space between thin shaft portion 42 and the inner circumference of cylindrical member 45. At this time, the air remaining in the internal space of support member 51 is exhausted into processing vessel 11, eliminating the pressure difference near O-ring 53, eliminating the positional misalignment of the components, and reducing the absolute value of the misalignment.

[0069] The above-described positional deviation caused by the pressure difference when the processing vessel 11 is decompressed is considered to be naturally caused by a small amount of air permeating from the sealing surface of the bellows into the internal space of the support member 51, even when the substrate processing apparatus 10 is in an idle state. Therefore, in the method for detecting the position of the lift pin 23 and the method for teaching the standby position of the lift pin 23 shown in Figures 8 and 9, it is preferable to repeatedly bring the pin-side step 44 into contact with the hole-side step 46 to eliminate the positional deviation caused by the pressure difference, and then teach the standby position of the lift pin 23. Specifically, the lift pin 23 is raised to the lift stop position and then lowered (lift pin raising and lowering process) at least twice, and the pin-side step 44 and the hole-side step 46 are repeatedly brought into contact with each other, and then the contact between the pin-side step 44 and the hole-side step 46 is detected. It is preferable to raise the lift pins 23 by the correction value from the position of the lift pins 23 when the contact between the pin-side step 44 and the hole-side step 46 is detected, and then lower them by the adjustment value. This reduces the deviation between the upper ends of the lift pins 23 and the mounting surface of the mounting table 15 when the lift pins 23 are raised by the correction value from their positions, thereby enabling the standby position of the lift pins 23 to be accurately taught.

[0070] However, the lift pins and the linking mechanism between the lift pins and the drive unit extend over a considerable length in the vertical direction, and therefore the overall amount of thermal expansion is large, reaching, for example, 200 μm. Therefore, in the conventional method of teaching the standby position of the lift pins using a weight, the influence of the amount of thermal expansion of the lift pins and the linking mechanism between the lift pins and the drive unit cannot be ignored, and the method is performed after heating the mounting table.

[0071] However, in this embodiment, a correction value is used to teach the standby positions of the lift pins 23. The correction value corresponds to the distance from the upper ends of the lift pins 23 to the mounting surface of the mounting table 15 when the pin-side step 44 abuts against the hole-side step 46, and is extremely short compared to the lift pins 23 and the entire coupling mechanism 50 of the lift pins 23 and the drive unit 24. In other words, the amount of thermal expansion of the correction value is considered to have little effect on teaching the standby positions of the lift pins 23. Therefore, in this embodiment, a correction value acquired when the temperatures of the side walls 13, the lid 14, and the mounting table 15 are not adjusted is used to teach the standby positions of the lift pins 23 in the idle substrate processing apparatus 10.

[0072] However, if the mounting table 15 and the lift pins 23 are made of different materials, the difference in thermal expansion may be significant even if the distance is equivalent to the correction value. Therefore, the correction value may be changed depending on the temperature of the mounting table 15 or the lift pins 23. For example, if the mounting table 15 is made of aluminum and the lift pins 23 are made of stainless steel, as the temperatures of the mounting table 15 and the lift pins 23 increase, the thermal expansion of the mounting table 15 becomes larger than that of the lift pins 23. In this case, the correction value is increased, and the position of the upper end of the lift pins 23 after the lift pins 23 are raised by the correction value is made to coincide with the position of the mounting surface of the mounting table 15. Note that a coefficient is preferably used as a means for changing the correction value. For example, it is preferable to prepare a database of coefficients corresponding to the temperatures of the mounting table 15 and the lift pins 23.

[0073] According to this embodiment, the position where the pin-side step 44 of the lift pin 23 abuts against the hole-side step 46 of the cylindrical member 45 is detected, and this detected position is used as a reference position for teaching the standby position of the lift pin 23. Therefore, it is not necessary to use a weight to teach the standby position of the lift pin 23, and the standby position of the lift pin 23 can be easily taught.

[0074] Furthermore, in this embodiment, since there is no need to use weights to teach the standby positions of the lift pins 23, it is not necessary to open the processing vessel 11 to the atmosphere when teaching the standby positions of the lift pins 23. As a result, even when the substrate processing apparatus 10 is in an idle state between etching processes and the processing vessel 11 is depressurized, teaching of the standby positions of the lift pins 23 can be performed, and the frequency of teaching the standby positions of the lift pins 23 can be improved.

[0075] Furthermore, even if the relative positional relationship between the lift pins 23 and the mounting surface of the mounting table 15 changes over time, it is possible to suppress the change from the adjusted value of the distance from the upper end of the lift pins 23 to the mounting surface of the mounting table 15 by increasing the frequency of teaching the standby position of the lift pins 23. This makes it possible to prevent the upper end of the lift pins 23 from affecting the etching process performed on the glass substrate G.

[0076] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and changes are possible within the scope of the gist of the present disclosure.

[0077] For example, in this embodiment, the contact between the pin-side step 44 and the hole-side step 46 is detected based on the accumulating pulse, but this detection may also be based on other indicators of the load on the drive unit 24. For example, the contact between the pin-side step 44 and the hole-side step 46 may also be detected based on the torque of the motor 38.

[0078] Specifically, if the pin-side step 44 abuts against the hole-side step 46 while the lift pin 23 is descending in the pin hole 22, the lift pin 23 cannot descend, and the torque changes with changes in the encoder value, as shown in Figure 10. At this time, the intermediate amount of change in torque is set as a threshold, and when the torque reaches this threshold, the abutment between the pin-side step 44 and the hole-side step 46 is detected. However, since torque is not as sensitive to changes in the movement mode of the lift pin 23 as accumulating pulses, it is preferable to use both torque and accumulating pulses when detecting the abutment between the pin-side step 44 and the hole-side step 46, rather than using torque alone.

[0079] The correction value was obtained by measuring, with the dial gauge 54, the amount of movement of the lift pin 23 from the position at which the contact between the pin-side step 44 and the hole-side step 46 was detected. However, as described above, the correction value corresponds to the distance from the upper end of the lift pin 23 to the mounting surface of the mounting table 15 when the pin-side step 44 contacts the hole-side step 46, and therefore can also be obtained from the design drawings (data). Therefore, if the assembly error of the lift pin device 21 to the mounting table 15 is very small, it is also possible to obtain the correction value from the design drawings (data).

[0080] Furthermore, in this embodiment, the control unit 36, to which the data sets of the accumulator pulses, the torque of the motor 38, and the encoder values ​​are input, detects the contact between the pin-side step 44 and the hole-side step 46. However, this data set may be output to an external client PC or server, and the external client PC or server may detect the contact between the pin-side step 44 and the hole-side step 46.

[0081] Furthermore, in this embodiment, the etching process is performed on a rectangular glass substrate G using a parallel-plate plasma etching apparatus. However, the types of apparatus and substrate are not limited to these. For example, the substrate is not limited to a glass substrate but may be a resin substrate, and the substrate may have a circular shape such as a wafer. Furthermore, the substrate may be made of other materials or have other shapes. Furthermore, the apparatus for processing the substrate is not limited to an etching apparatus but may be a processing apparatus for performing other processes, such as a film forming apparatus or an ashing apparatus. Furthermore, the plasma generation method is not limited to parallel-plate plasma but may be other plasma generation methods, such as inductively coupled plasma or microwave plasma. [Explanation of symbols]

[0082] G Glass substrate 10. Substrate processing equipment 11 Processing container 15 Mounting table 21 Lift pin device 22 pin holes 23 Lift pin 24 Drive unit 42 Thin shaft part 43 Thick shaft part 44 Pin side step 45 Cylindrical member 46 Hole side step

Claims

1. 1. A method for detecting the position of a lift pin that is disposed in a pin hole that opens into a mounting surface of a mounting table that is disposed inside a processing chamber and on which a substrate is placed, the lift pin moving in a vertical direction in the pin hole to protrude and retract with respect to the mounting surface, the lift pin extends in the up-down direction and has a thin shaft portion and a thick shaft portion provided above the thin shaft portion and having a diameter larger than that of the thin shaft portion, and a first step is formed at a location where the thick shaft portion transitions to the thin shaft portion; the lift pins are connected to a drive mechanism that moves the lift pins in the up and down direction; the pin hole is drilled in the vertical direction and has a large diameter portion and a small diameter portion that is provided below the large diameter portion and has a diameter smaller than the large diameter portion, and a second step is formed at a location where the large diameter portion changes to the small diameter portion, a lift pin raising / lowering step of raising the lift pin and then lowering it to bring the first step into contact with the second step; a contact detection step of detecting contact between the first step and the second step based on an index of a load of the drive mechanism, during the lift pin lifting / lowering step.

2. 2. The lift pin position detection method according to claim 1, wherein the contact detection step detects the contact between the first step and the second step based on an index of a load of the drive mechanism after the lift pin raising and lowering step has been performed at least twice.

3. 2. The method for detecting the position of a lift pin according to claim 1, further comprising: raising the lift pin by a correction value from the position of the lift pin when the contact between the first step and the second step is detected.

4. 4. The lift pin position detection method according to claim 3, wherein the correction value is a movement amount of the lift pin corresponding to a distance from an upper end of the lift pin to the placement surface when the first step abuts against the second step.

5. The lift pin position detection method according to claim 4 , wherein the correction value is acquired in a state where the processing vessel is open to the atmosphere.

6. 5. The lift pin position detection method according to claim 4, wherein the correction value is obtained without heating the mounting table.

7. 5. The lift pin position detection method according to claim 4, further comprising: raising the lift pin by the correction value from the position of the lift pin when the contact between the first step and the second step is detected; and then lowering the lift pin by a predetermined adjustment value to move the lift pin to a standby position.

8. The lift pin position detection method according to claim 3 , wherein the lift pin lifting / lowering step and the contact detection step are performed in a state where the processing chamber is decompressed.

9. 2. The lift pin position detection method according to claim 1, wherein the index of the load on the drive mechanism is an accumulated pulse obtained by subtracting an integrated value of feedback pulses proportional to an actual rotation speed of the drive mechanism from an integrated value of command pulses generated according to a set speed at which the lift pins are moved.

10. A processing vessel; a mounting table disposed inside the processing chamber and configured to mount a substrate thereon; a lift pin disposed in a pin hole that opens to a mounting surface of the mounting table, the lift pin moving in a vertical direction in the pin hole to project and retract with respect to the mounting surface; a drive mechanism that moves the lift pins in the up and down direction; a control unit, the lift pin extends in the up-down direction and has a thin shaft portion and a thick shaft portion provided above the thin shaft portion and having a diameter larger than that of the thin shaft portion, and a first step is formed at a location where the thick shaft portion transitions to the thin shaft portion; the pin hole is drilled in the vertical direction and has a large diameter portion and a small diameter portion that is provided below the large diameter portion and has a diameter smaller than the large diameter portion, and a second step is formed at a location where the large diameter portion changes to the small diameter portion, The control unit detects contact between the first step and the second step when the lift pins are raised and then lowered based on an index of a load of the drive mechanism.

11. The substrate processing apparatus according to claim 10 , wherein the small diameter portion is formed by a cylindrical member inserted into the pin hole.

12. The substrate processing apparatus according to claim 11 , wherein the cylindrical member is configured to be movable in the pinhole in the up and down direction.

Images