JP2022053960A - Processing device and substrate holding method in processing device - Google Patents

Abstract

To suppress the generation of particles on a mounting table on which a substrate is placed, the back surface of the substrate, and the like inside a chamber of a processing device.SOLUTION: A processing device of a substrate includes a chamber, a mounting table that is provided inside the chamber and on which the substrate is placed, a lifter that raises and lowers the substrate with respect to the mounting table, a suction state detection unit that is provided on the lifter and that detects the suction state between the substrate and the mounting table, and a control unit that controls the lifter and the suction state detection unit, and the control unit adjusts a temperature difference between the substrate and the mounting table such that the stress generated between the substrate and the mounting table is set to be equal to or less than the maximum static friction force between the substrate and the mounting table due to the operation of the lifter and the suction state detection unit, and controls the substrate to be held by the mounting table.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a processing apparatus and a substrate holding method in the processing apparatus.

Patent Document 1 discloses a method for reducing particle generation in an electrostatic chuck used in a semiconductor manufacturing apparatus. In this particle generation reduction method, the stress caused by the difference between the thermal expansion of the wafer and the thermal expansion of the electrostatic chuck is released by sliding and moving the wafer with respect to the suction surface. There is also a technology to release stress by applying a pulse voltage to the electrostatic chuck or by means of flowing backside gas between the adsorption surface and the wafer, and adjusting the timing by monitoring the wafer temperature and the like. It has been disclosed.

Japanese Unexamined Patent Publication No. 2000-21964

The technique according to the present disclosure suppresses the generation of particles on the mounting table on which the substrate is placed, the back surface of the substrate, and the like inside the chamber of the processing apparatus.

One aspect of the present disclosure is a substrate processing apparatus, which comprises a chamber, a mounting table provided inside the chamber on which the substrate is placed, and a lifter for raising and lowering the substrate with respect to the above-mentioned table. The lifter is provided with a suction state detection unit for detecting the suction state between the substrate and the above-mentioned table, and a control unit for controlling the lifter and the suction state detection unit. The control unit is the lifter. And the operation of the adsorption state detection unit causes the stress generated between the substrate and the above-mentioned pedestal to be equal to or less than the maximum static friction force between the substrate and the pedestal. It is a processing apparatus that adjusts the temperature difference between the two and controls the holding of the substrate on the above-mentioned table.

According to the present disclosure, it is possible to suppress the generation of particles on the mounting table on which the substrate is placed, the back surface of the substrate, and the like inside the chamber of the processing apparatus.

It is a vertical sectional view which shows the outline of the structure of the plasma processing apparatus which concerns on this embodiment. It is a schematic explanatory drawing about the adsorption state detection means of the wafer which concerns on 1st Embodiment. It is a schematic explanatory drawing about the adsorption state detection means of the wafer which concerns on 2nd Embodiment. It is a schematic explanatory drawing about the adsorption state detection means of the wafer which concerns on 3rd Embodiment. It is a flow figure which shows an example of the wafer holding method. It is a flow figure which shows an example of the wafer holding method.

In the processing apparatus and the substrate holding method in the processing apparatus according to the present disclosure, the processing target and the type of the processing apparatus are not particularly limited. In the embodiment for carrying out the following invention, in the manufacture of a semiconductor device, a plasma processing device is used as a processing device, and a semiconductor wafer as a substrate (adsorbed body) (hereinafter, also referred to as “base” or “wafer”) is used. A case where plasma processing is performed will be described. Further, the type of the adsorbent that adsorbs the substrate is not particularly limited, and the following describes as an example a mounting table having an electrostatic chuck that adsorbs the substrate to the adsorption surface by applying a voltage. do.

In the semiconductor device manufacturing process, the wafer is plasma treated. In plasma processing, plasma is generated by exciting a processing gas, and the wafer is processed by the plasma.

The plasma processing is performed by the plasma processing apparatus. Plasma processing equipment generally includes a chamber, a mounting table, and a radio frequency (RF) power supply. In one example, the high frequency power supply comprises a first high frequency power supply and a second high frequency power supply. The first high frequency power supply supplies the first high frequency power to generate a plasma of gas in the chamber. The second high frequency power supply supplies a second high frequency power for bias to the lower electrode in order to attract ions to the wafer. The chamber defines its interior space as a processing space where plasma is generated. The mounting table is provided in the chamber. The mounting table has a lower electrode and an electrostatic chuck. The electrostatic chuck is provided on the lower electrode. In one example, an edge ring is arranged on the electrostatic chuck so as to surround the wafer mounted on the electrostatic chuck. The arrangement of the edge ring is not limited to the electrostatic chuck. Edge rings are provided to improve the uniformity of plasma processing on the wafer.

In plasma processing, for example, when a wafer is placed on a mounting table during wafer loading or process switching, stress is generated between the mounting table and the wafer having different linear expansion coefficients due to the temperature difference between the two. Due to the generated stress, rubbing occurs between the mounting table and the wafer, and foreign matter (hereinafter, also referred to as “particle”) is generated. These particles are caused by, for example, scratching on the back surface of the wafer or shedding on the surface of the electrostatic chuck of the mounting table. Since the particles thus generated adhere to the surface of the wafer or other wafers and reduce the yield, it is desired to suppress the generation of the particles.

Conventionally, in order to remove particles, a method of opening the chamber and cleaning the surface of the electrostatic chuck has been performed. There is also a method in which a wafer that is not a processing target (for example, a dummy wafer) is carried into the chamber and adsorbed on the surface of the electrostatic chuck, and particles on the surface of the electrostatic chuck are attached to the wafer that is not the processing target and discharged to the outside of the chamber. Was known.

However, in order to open the chamber for cleaning, the operation of the chamber must be stopped, and it takes time (for example, several days) until the chamber can be operated, which may reduce the productivity of the processing apparatus. I am concerned. In addition, even if the particles are attached to a wafer that is not the processing target, the particles cannot be reliably discharged, and the particles fall on the surface of the electrostatic chuck, in the chamber, on the transport system equipment, etc. during the discharge, resulting in a low yield. There is a risk of deterioration.

In view of these points, in Patent Document 1, in order to suppress the generation of particles, the stress generated between the mounting table and the wafer due to the temperature difference is applied to turn on / off the wafer adsorption. It is disclosed that the wafer is repeatedly opened by sliding and moving it with respect to the suction surface. Further, a technique of adjusting the timing of stress release by monitoring the wafer temperature is also disclosed.

However, in the method disclosed in Patent Document 1, it is not possible to accurately specify when the wafer is peeled off from the surface of the mounting table (electrostatic chuck). Even if the time until peeling is obtained by experiment, the state of the surface of the mounting surface changes with time while processing many wafers, and the time until peeling changes, so the adsorption OFF time for stress release is sufficient. The throughput is reduced because it is necessary to take it.

The technique according to the present disclosure is described before the stress generated due to the temperature difference between the substrate and the mounting table (electrostatic chuck) on which the substrate is placed becomes large inside the chamber of the processing apparatus. , The step of turning off the adsorption and separating the wafer from the mounting table (electrostatic chuck) is performed. Specifically, the temperature difference between the two is adjusted within a predetermined range so that the stress between the two is equal to or less than the maximum static friction force between the two, and the wafer is held on the mounting table to hold the particles. Suppress the occurrence. Hereinafter, the processing apparatus according to the present embodiment and the substrate holding method in the processing apparatus will be described with reference to the drawings. In the present specification and the drawings, the elements having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

<Plasma processing equipment>
First, the plasma processing apparatus according to the present embodiment will be described. FIG. 1 is a vertical cross-sectional view showing an outline of the configuration of the plasma processing apparatus 1. The plasma processing device 1 is a capacitively coupled plasma processing device. Further, in the plasma processing apparatus 1, plasma processing is performed on the wafer W as a substrate. The wafer W is a wafer on which a desired plasma treatment is performed, and is, for example, a wafer having a pattern formed on its surface. The plasma treatment is not particularly limited, but for example, an etching treatment, a film forming treatment, a diffusion treatment and the like are performed.

As shown in FIG. 1, the plasma processing apparatus 1 has a chamber 10 having a substantially cylindrical shape. The chamber 10 defines a processing space S in which plasma is generated. The chamber 10 is made of, for example, aluminum. Chamber 10 is connected to the ground potential. A plasma-resistant film is formed on the inner wall surface of the chamber 10, that is, the wall surface defining the processing space S. This film may be a ceramic film such as a film formed by anodizing or a film formed from yttrium oxide.

A mounting table 11 on which the wafer W is mounted is housed inside the chamber 10. The mounting table 11 has a lower electrode 12 and an electrostatic chuck 13. Further, the mounting table 11 is provided with an edge ring 14 so as to surround the wafer W mounted on the mounting table 11. An electrode plate (not shown) made of, for example, aluminum may be provided on the lower surface side of the lower electrode 12.

The lower electrode 12 is made of a conductive metal such as aluminum and has a substantially disk shape.

A refrigerant flow path 15a is formed inside the lower electrode 12. Refrigerant is supplied to the refrigerant flow path 15a from a chiller unit (not shown) provided outside the chamber 10 via the refrigerant inlet pipe 15b. The refrigerant supplied to the refrigerant flow path 15a returns to the chiller unit via the refrigerant outlet flow path 15c. By circulating a refrigerant such as cooling water in the refrigerant flow path 15a, the electrostatic chuck 13, the edge ring 14, and the wafer W can be cooled to a desired temperature.

The electrostatic chuck 13 is provided on the lower electrode 12. The electrostatic chuck 13 is a member configured to be able to attract and hold both the wafer W and the edge ring 14 by electrostatic force. The surface of the central portion of the electrostatic chuck 13 is formed higher than the surface of the outer peripheral portion. The surface of the central portion of the electrostatic chuck 13 is the wafer mounting surface on which the wafer W is mounted, and the surface of the outer peripheral portion of the electrostatic chuck 13 is the edge ring mounting surface on which the edge ring 14 is mounted. .. The details of the configuration of the electrostatic chuck 13 will be described later.

A first electrode 16a for sucking and holding the wafer W is provided at the center of the inside of the electrostatic chuck 13. Inside the electrostatic chuck 13, a second electrode 16b for sucking and holding the edge ring 14 is provided on the outer peripheral portion. The electrostatic chuck 13 has a configuration in which electrodes 16a and 16b are sandwiched between insulating materials made of an insulating material.

A DC voltage from a DC power source (not shown in FIG. 1) is applied to the first electrode 16a. Due to the electrostatic force generated by this, the wafer W is adsorbed and held on the surface of the central portion of the electrostatic chuck 13. Similarly, a DC voltage from a DC power source (not shown) is applied to the second electrode 16b. Due to the electrostatic force generated by this, the edge ring 14 is attracted and held on the surface of the outer peripheral portion of the electrostatic chuck 13.

The edge ring 14 is an annular member arranged so as to surround the wafer W placed on the surface of the central portion of the electrostatic chuck 13. The edge ring 14 is provided to improve the uniformity of plasma processing. Therefore, the edge ring 14 is made of a material appropriately selected according to the plasma treatment, and may be made of, for example, quartz, Si, SiC, or the like.

The mounting table 11 configured as described above is fastened to a substantially cylindrical support member 17 provided at the bottom of the chamber 10. The support member 17 is made of an insulator such as ceramic or quartz.

Although not shown, the mounting table 11 may include a temperature control module configured to adjust at least one of the electrostatic chuck 13, the edge ring 14, and the wafer W to a desired temperature. The temperature control module may include a heater, a flow path, or a combination thereof. A temperature control fluid such as a refrigerant or a heat transfer gas flows through the flow path. Further, the upper surface (mounting surface) of the mounting table 11 does not necessarily have to have a flat shape, and for example, it may have a fine uneven shape and a configuration in which a temperature control fluid such as a heat transfer gas flows in the concave portion.

A lifter 20 for raising and lowering the wafer W with respect to the mounting table 11 is provided below the mounting table 11 and inside the support member 17. The lifter 20 has, for example, an elevating pin 21, a support member 22, and a drive unit 23.

The elevating pin 21 is a columnar member that elevates and descends from the surface of the central portion of the electrostatic chuck 13 so as to be recessed, and is formed of, for example, ceramic. Three or more elevating pins 21 are provided at intervals from each other along the circumferential direction of the electrostatic chuck 13, that is, the circumferential direction of the surface. The elevating pins 21 are provided, for example, at equal intervals along the circumferential direction. The elevating pin 21 is provided so as to extend in the vertical direction.

The elevating pin 21 is inserted into a through hole 24 extending downward from the surface of the central portion of the electrostatic chuck 13 to the bottom surface of the lower electrode 12. That is, the through hole 24 is formed so as to penetrate the central portion of the electrostatic chuck 13 and the lower electrode 12.

The support member 22 supports a plurality of elevating pins 21. The drive unit 23 generates a driving force for raising and lowering the support member 22, and raises and lowers a plurality of raising and lowering pins 21. The drive unit 23 has a motor (not shown) that generates the drive force.

The plasma processing apparatus 1 further includes a first high frequency (RF: Radio Frequency) power supply 30, a second high frequency power supply 31, a first matching unit 32, and a second matching unit 33. The first high frequency power supply 30 and the second high frequency power supply 31 are connected to the lower electrode 12 via the first matching unit 32 and the second matching unit 33, respectively.

The first high frequency power source 30 is a power source that generates high frequency power for plasma generation. The frequency may be 27 MHz to 100 MHz from the first high frequency power supply 30, and in one example, a high frequency power HF of 40 MHz is supplied to the lower electrode 12. The first matching unit 32 has a circuit for matching the output impedance of the first high frequency power supply 30 with the input impedance on the load side (lower electrode 12 side). The first high frequency power supply 30 may not be electrically connected to the lower electrode 12, but may be connected to the shower head 40, which is the upper electrode, via the first matching unit 32.

The second high frequency power supply 31 generates a high frequency power (bias power) LF for drawing ions into the wafer W, and supplies the high frequency power LF to the lower electrode 12. The frequency of the high frequency power LF may be a frequency in the range of 200 kHz to 13.56 MHz, and in one example, it is 400 kHz. The second matching unit 33 has a circuit for matching the output impedance of the second high frequency power supply 31 with the input impedance on the load side (lower electrode 12 side). A DC (Direct Current) pulse generation unit may be used instead of the second high frequency power supply 31.

A shower head 40 is provided above the mounting table 11 so as to face the mounting table 11. The shower head 40 has an electrode plate 41 arranged facing the processing space S, and an electrode support 42 provided above the electrode plate 41. The electrode plate 41 functions as a pair of upper electrodes with the lower electrode 12. When the first high frequency power supply 30 is electrically connected to the lower electrode 12 as described later, the shower head 40 is connected to the ground potential. The shower head 40 is supported on the upper part (ceiling surface) of the chamber 10 via the insulating shielding member 43.

The electrode plate 41 is formed with a plurality of gas outlets 41a for supplying the processing gas sent from the gas diffusion chamber 42a, which will be described later, to the processing space S. The electrode plate 41 is made of, for example, a conductor or a semiconductor having a low electrical resistivity with little Joule heat generated.

The electrode support 42 supports the electrode plate 41 in a detachable manner. The electrode support 42 has a structure in which a plasma-resistant film is formed on the surface of a conductive material such as aluminum. This film may be a ceramic film such as a film formed by anodizing or a film formed from yttrium oxide. A gas diffusion chamber 42a is formed inside the electrode support 42. From the gas diffusion chamber 42a, a plurality of gas flow holes 42b communicating with the gas ejection port 41a are formed. Further, the gas diffusion chamber 42a is formed with a gas introduction hole 42c connected to a gas supply pipe 53, which will be described later.

Further, a gas supply source group 50 for supplying the processing gas to the gas diffusion chamber 42a is connected to the electrode support 42 via a flow rate control device group 51, a valve group 52, a gas supply pipe 53, and a gas introduction hole 42c. ing.

The gas supply source group 50 has a plurality of types of gas supply sources necessary for plasma treatment and the like. The flow rate control device group 51 includes a plurality of flow rate controllers, and the valve group 52 includes a plurality of valves. Each of the plurality of flow rate controllers in the flow rate control device group 51 is a mass flow controller or a pressure control type flow rate controller. In the plasma processing apparatus 1, the processing gas from one or more gas supply sources selected from the gas supply source group 50 passes through the flow rate control device group 51, the valve group 52, the gas supply pipe 53, and the gas introduction hole 42c. It is supplied to the gas diffusion chamber 42a. Then, the processing gas supplied to the gas diffusion chamber 42a is dispersed and supplied in a shower shape in the processing space S via the gas flow hole 42b and the gas ejection port 41a.

The plasma processing apparatus 1 is provided with a depot shield 60 detachably provided along the inner wall of the chamber 10. The depot shield 60 suppresses the adhesion of the depot to the inner wall of the chamber 10, and is configured by, for example, coating an aluminum material with ceramics such as yttrium oxide. Similarly, a depot shield 61 is detachably provided on the outer peripheral surface of the support member 17, which is a surface facing the depot shield 60.

A baffle plate 62 is provided at the bottom of the chamber 10 between the inner wall of the chamber 10 and the support member 17. The baffle plate 62 is configured by, for example, coating an aluminum material with ceramics such as yttrium oxide. A plurality of through holes are formed in the baffle plate 62. The processing space S communicates with the exhaust port 63 via the baffle plate 62. An exhaust device 64 such as a vacuum pump is connected to the exhaust port 63, and the exhaust device 64 is configured to be able to reduce the pressure in the processing space S.

Further, a wafer W carry-in outlet 65 is formed on the side wall of the chamber 10, and the carry-in outlet 65 can be opened and closed by a gate valve 66.

The plasma processing apparatus 1 described above is provided with a control unit 70. The control unit 70 is, for example, a computer equipped with a CPU, a memory, or the like, and has a program storage unit (not shown). The program storage unit stores a program that controls the entire process such as plasma processing in the plasma processing device 1. The program may be recorded on a storage medium readable by a computer and may be installed on the control unit 70 from the storage medium.

<Plasma processing method>
Next, the plasma processing performed by using the plasma processing apparatus 1 configured as described above will be described.

First, the wafer W is carried into the chamber 10 and the wafer W is placed on the electrostatic chuck 13. At this time, the wafer W is placed on the electrostatic chuck 13 so that the center of the wafer W is at the same position as the center of the electrostatic chuck 13 in a plan view. The position of this wafer W is the processing position in the present disclosure. After that, by applying a DC voltage to the first electrode 16a of the electrostatic chuck 13, the wafer W is electrostatically attracted to and held by the electrostatic chuck 13 by Coulomb force. At the same time, by operating the refrigerant flow path 15a and the temperature control module (not shown) to set the temperature of the mounting table 11 to a desired temperature, the temperature of the mounted wafer W can be brought closer to the desired temperature. Further, after the wafer W is carried in, the inside of the chamber 10 is depressurized to a desired degree of vacuum by the exhaust device 64.

Next, the processing gas is supplied from the gas supply source group 50 to the processing space S via the shower head 40. Further, the high frequency power HF for plasma generation is supplied to the lower electrode 12 by the first high frequency power supply 30, and the processing gas is excited to generate plasma. At this time, the high frequency power LF for ion attraction may be supplied by the second high frequency power supply 31. Then, plasma treatment is applied to the wafer W by the action of the generated plasma.

When the plasma processing is completed, first, the supply of the high frequency power HF from the first high frequency power source 30 and the supply of the processing gas by the gas supply source group 50 are stopped. Further, when the high frequency power LF is supplied during the plasma processing, the supply of the high frequency power LF is also stopped. Next, the supply of the heat transfer gas to the back surface of the wafer W is stopped, and the adsorption and holding of the wafer W by the electrostatic chuck 13 is stopped.

After that, the wafer W is carried out from the chamber 10, and a series of plasma treatments on the wafer W are completed.

In the plasma processing, the high frequency power HF from the first high frequency power supply 30 may not be used, and only the high frequency power LF from the second high frequency power supply 31 may be used to generate plasma.

Further, although the case where one step is performed as plasma processing has been described here, there are cases where two or more different processes are performed on the same wafer W. In that case, a different processing gas may be used for each process, or the process conditions may be changed. When performing two or more types of processes, the desired temperature of the wafer W placed on the electrostatic chuck 13 may differ for each process. At that time, the temperature of the wafer W is changed by changing the set temperature of the mounting table 11.

<Stress between wafer and mounting table>
For example, when the plasma processing is performed in the plasma processing apparatus 1 configured as described above with reference to FIG. 1, the wafer W is carried into the chamber 10 before the processing is started, and the wafer W is carried on the electrostatic chuck 13. The step of placing the wafer W on the wafer W is performed. At that time, a wafer W having a room temperature, for example, is placed on the mounting table 11 in a state where the temperature of the mounting table 11 is set to a predetermined set temperature by operating the refrigerant flow path 15a and the temperature control module (not shown).

That is, at the start of plasma processing, there is a temperature difference between the mounting table 11 (electrostatic chuck 13) and the wafer W, and electrostatic adsorption is performed in that state, so that stress is generated between the two due to the temperature difference. Occurs. When this stress exceeds the maximum static friction force between the mounting table 11 and the wafer W, particles are generated due to scratches on the back surface of the wafer W and shedding on the surface of the electrostatic chuck 13. The generated particles adhere to the surface of the wafer W, the surface of another wafer, or the like to reduce the yield.

Therefore, in the present embodiment, attention is paid to the stress state between the mounting table 11 and the wafer W, the wafer W is surely separated from the mounting table 11 at an effective timing to release the stress, and then promptly. The process of reattaching the wafer W to the mounting table 11 was repeated. The stress release is performed by releasing the adsorption by the electrostatic chuck 13 on the mounting table 11 and physically pushing the wafer W away from the mounting table 11 by using the elevating pin 21 of the lifter 20. Hereinafter, specific means for detecting the adsorption state (or separation state) between the mounting table 11 and the wafer W will be described with reference to the drawings. The pushing distance (separation distance) of the wafer W from the mounting table 11 here is arbitrary, and it is sufficient if the physical separation can be confirmed. For example, about 0.5 mm is preferable.

<First Embodiment>
FIG. 2 is a schematic explanatory view of the wafer adsorption state detection unit according to the first embodiment, and is shown focusing on the configuration centered on the mounting table 11 and the wafer W. As described above, a lifter 20 for raising and lowering the wafer W with respect to the mounting table 11 is provided below the mounting table 11. In the present embodiment, as shown in FIG. 2, a torque meter 80 for measuring the torque in the lifter 20 is attached as a suction state detecting unit. The torque meter 80 measures, for example, the torque generated in the elevating pin 21 while the elevating pin 21 is being driven by the driving unit 23.

When the wafer W sucked on the mounting table 11 is lifted and separated by raising the elevating pin 21 (so-called pin-up), the wafer W is attracted to the mounting table 11 and becomes a reaction force. The torque load based on this is greatly measured, and the torque load is greatly reduced when the wafer W is completely peeled off from the mounting table 11. That is, when the adsorption state of the wafer W is detected, the torque is measured at any time by the torque meter 80, and the time when the torque load is greatly reduced indicates the state in which the wafer W is completely peeled off from the mounting table 11 and separated from the mounting table 11. It can be said that there is.

In the state where the wafer W is started to be adsorbed on the mounting table 11, the mounting table 11 is temperature-controlled to the set temperature, whereas the wafer W is in principle at room temperature (room temperature). That is, there is a large temperature difference between the mounting table 11 and the wafer W. In that state, while detecting the adsorption state with the torque meter 80, the electrostatic adsorption is released when the temperature difference ΔT between the two reaches a predetermined threshold value, and the wafer W is lifted by driving (pin-up) the lifter 20. When the separation of the wafer W from the mounting table 11 is confirmed by the detection by the torque meter 80, the wafer W is lowered by driving the lifter 20 (pin down) to perform electrostatic adsorption. Then, the same process is repeated once again when the temperature difference ΔT reaches a predetermined threshold value. By repeating the same steps thereafter, the wafer W finally reaches a desired temperature, and the temperature difference ΔT becomes a value that does not exceed a predetermined threshold value. In such a state, the wafer W is held and adsorbed on the mounting table 11 to perform a processing step such as plasma processing.

The threshold value of the temperature difference ΔT between the mounting table 11 and the wafer W is set so that the stress generated between the mounting table 11 and the wafer W is equal to or less than the maximum static friction force between the two. It is preferable to determine based on. This is because if the stress generated between the mounting table 11 and the wafer W is equal to or less than the maximum static friction force between the two, the generated stress does not cause rubbing between the two, and the generation of particles is suppressed. Because. Specifically, as conditions under which the wafer W can be held and adsorbed on the mounting table 11 without the need to release stress, the temperature difference ΔT is preferably 5 ° C. or lower, and more preferably ΔT is 1 ° C. or lower.

<Second embodiment>
FIG. 3 is a schematic explanatory view of the adsorption state detection unit of the wafer according to the second embodiment, and is illustrated focusing on the configuration centered on the mounting table 11 and the wafer W. As shown in FIG. 3, a first electrode 16a for sucking and holding the wafer W is provided inside the electrostatic chuck 13. In the present embodiment, the capacitance meter 85 is attached as a suction state detection unit to the voltage supply line 84 for applying a voltage to the first electrode 16a.

When the wafer W sucked on the mounting table 11 is lifted and separated by raising the elevating pin 21 (so-called pin-up), the wafer W is mounted on the mounting table 11 as compared with the state where the wafer W is sucked on the mounting table 11. The capacitance becomes small when the wafer W is completely peeled off from the pedestal 11. That is, when the adsorption state of the wafer W is detected, the measurement by the capacitance meter 85 is performed at any time, and when the capacitance is greatly reduced, the wafer W is completely peeled off from the mounting table 11 and separated from the mounting table 11. It can be said that it shows.

In the present embodiment, as in the first embodiment, when there is a temperature difference between the mounting table 11 and the wafer W, the capacitance meter 84 detects the adsorption state and the temperature difference between the two is ΔT. When the temperature reaches a predetermined threshold value, the electrostatic adsorption is released, and the wafer W is lifted by driving (pin-up) the lifter 20. Then, when the separation of the wafer W from the mounting table 11 is confirmed by the detection by the capacitance meter 84, the wafer W is lowered by driving (pin down) the lifter 20 to perform electrostatic adsorption. Then, the same process is repeated once again when the temperature difference ΔT reaches a predetermined threshold value. By repeating the same steps thereafter, the wafer W finally reaches a desired temperature, and the temperature difference ΔT becomes a value that does not exceed a predetermined threshold value. In such a state, the wafer W is held and adsorbed on the mounting table 11 to perform a processing step such as plasma processing.

<Third embodiment>
FIG. 4 is a schematic explanatory view of the wafer adsorption state detection unit according to the third embodiment, and is shown focusing on the configuration centered on the mounting table 11 and the wafer W. As shown in FIG. 4, a first electrode 16a for sucking and holding the wafer W is provided inside the electrostatic chuck 13. In the present embodiment, a galvanometer 90 is attached as a suction state detection unit to a voltage supply line 84 for applying a voltage to the first electrode 16a.

When the wafer W sucked on the mounting table 11 is lifted and separated by raising the elevating pin 21 (so-called pin-up), the wafer W is mounted on the mounting table 11 as compared with the state where the wafer W is sucked on the mounting table 11. A current flows through the voltage supply line 84 when the wafer W is completely peeled off from the pedestal 11. That is, when the adsorption state of the wafer W is detected, the detection by the galvanometer 90 is performed at any time, and the time point at which the current flows indicates the state in which the wafer W is completely peeled off from the mounting table 11 and separated from the mounting table 11. I can say.

In the present embodiment, as in the first and second embodiments, when there is a temperature difference between the mounting table 11 and the wafer W, the temperature of both is detected by the galvanometer 90 while detecting the adsorption state. When the difference ΔT reaches a predetermined threshold value, the electrostatic adsorption is released, and the wafer W is lifted by driving (pin-up) the lifter 20. Then, when the separation of the wafer W from the mounting table 11 is confirmed by the detection by the galvanometer 90, the wafer W is lowered by driving (pin down) the lifter 20 to perform electrostatic adsorption. Then, the same process is repeated once again when the temperature difference ΔT reaches a predetermined threshold value. By repeating the same steps thereafter, the wafer W finally reaches a desired temperature, and the temperature difference ΔT becomes a value that does not exceed a predetermined threshold value. In such a state, the wafer W is held and adsorbed on the mounting table 11 to perform a processing step such as plasma processing.

<Specific wafer holding method>
The adsorption state detection unit described in the first to third embodiments releases the stress by reliably separating the wafer W from the mounting table 11, and then promptly sucks the wafer W to the mounting table 11 again. By repeating the above steps, the wafer W can be held and adsorbed on the mounting table 11. Such a wafer holding method can be carried out at various timings of plasma processing performed by the plasma processing apparatus 1 according to the present embodiment.

5 and 6 are flow charts showing an example of a wafer holding method. As shown in FIG. 5, as a flow when the plasma processing step is one step, first, as step S11, the wafer W is carried into the chamber 10 and placed on the mounting table 11. At this stage, the mounting table 11 is temperature-controlled to a predetermined set temperature for plasma processing, whereas the wafer W at the time of carrying in is at room temperature (room temperature). Therefore, in order to release the stress caused by the temperature difference between the mounting table 11 and the wafer W, the wafer W is held and sucked by using the suction state detection unit as described in the first to third embodiments. Is performed (step S12).

Then, when the wafer W reaches a desired temperature, the temperature difference ΔT described above becomes a value that does not exceed a predetermined threshold value, and the wafer W is held on the mounting table 11, a predetermined plasma treatment is performed as step S13. .. The plasma treatment here is arbitrary, and is, for example, an etching treatment, a film forming treatment, a diffusion treatment, and the like. Then, when the plasma treatment is completed, the wafer W is carried out of the chamber 10 and a series of processes is completed (step S14).

Further, as plasma processing, different plasma processing under a plurality of conditions may be continuously performed in the same chamber 10. FIG. 6 shows a flow when the first plasma treatment and the second plasma treatment are carried out. In the step shown in FIG. 6, first, as step S21, the wafer W is carried into the chamber 10 and placed on the mounting table 11. At this stage, the mounting table 11 is temperature-controlled to the set temperature for the first plasma processing, while the wafer W at the time of carrying in is at room temperature (room temperature). Therefore, in order to release the stress caused by the temperature difference between the mounting table 11 and the wafer W, the wafer W is held and sucked by using the suction state detection unit as described in the first to third embodiments. Is performed (step S22). Then, when the wafer W reaches a desired temperature and the temperature difference ΔT described above becomes a value that does not exceed a predetermined threshold value and the wafer W is held on the mounting table 11, the first plasma treatment is performed as step S23. ..

Subsequently, after the completion of the first plasma treatment, the mounting table 11 is temperature-controlled to the set temperature for the second plasma treatment, which is the next step. When the conditions of the first plasma treatment and the second plasma treatment are different, naturally, the set temperature is also different. Since the wafer W temperature at the completion of the first plasma processing is a temperature based on the conditions of the first plasma processing, when the temperature of the mounting table 11 changes, it is caused by the temperature difference between the mounting table 11 and the wafer W again. Stress is generated. Therefore, in order to release the stress, the wafer W is held and adsorbed by using the adsorption state detecting unit as described in the first to third embodiments (step S24). Then, when the wafer W reaches a desired temperature, the temperature difference ΔT described above becomes a value that does not exceed a predetermined threshold value, and the wafer W is held on the mounting table 11, the second plasma treatment is performed as step S25. .. Then, when the second plasma treatment is completed, the wafer W is carried out of the chamber 10 and a series of processes is completed (step S26).

According to the process described with reference to FIGS. 5 and 6, stress is generated due to the temperature difference between the mounting table 11 and the wafer W, and rubbing is suppressed to generate particles. For example, when different plasma treatments under a plurality of conditions are continuously performed in the same chamber 10 as plasma treatments, the wafer holding method according to the present disclosure can be applied before each plasma treatment to control the temperature conditions and the like. Even if there is a change, the generation of particles can be suppressed.

Although the case where the wafer holding method according to the present disclosure is applied at the start of plasma processing and between a plurality of plasma treatments has been described here, the scope of application of the present disclosure is not limited to this. That is, when control such as changing the set temperature of the mounting table 11 is adopted during the plasma processing, the wafer holding method according to the present disclosure may be applied each time the set temperature is changed.

Further, in the embodiment described above, the case where the mounting table 11 has an electrostatic chuck 13 as an adsorbent and the wafer W is adsorbed by electrostatic adsorption has been illustrated and described. However, the scope of this disclosure is not limited to this. For example, vacuum suction may be used as an adsorbent for adsorbing the wafer W on the mounting table 11. In that case, in addition to the torque meter 80, a pressure gauge or the like may be used as the adsorption state detection unit.

Further, in the above embodiment, the wafer W has been described as an adsorption target, but the scope of application of the present disclosure is not limited to this. For example, in a plasma processing apparatus, members such as an edge ring and a focus ring around a wafer may be attracted and held by the mounting table 11. The present disclosure is useful for any member that is adsorbed and held in such a chamber and may be stressed by temperature differences.

Further, the plasma processing device 1 of the above embodiment is a capacitive coupling type plasma processing device, but the plasma processing device to which the present disclosure is applied is not limited to this. For example, the plasma processing device may be an inductively coupled plasma processing device.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The above embodiments may be omitted, replaced or modified in various embodiments without departing from the scope of the appended claims and their gist.

1 Plasma processing equipment 10 Chamber 11 Mounting table 20 Lifter 70 Control unit 80 Torque meter W Wafer

Claims (7)

It is a substrate processing device
With the chamber
A mounting table provided inside the chamber on which the substrate is placed, and
A lifter that raises and lowers the substrate with respect to the above-mentioned stand, and
A suction state detecting unit provided on the lifter to detect the suction state between the substrate and the above-mentioned table, and a suction state detecting unit.
The lifter and the control unit for controlling the adsorption state detection unit are provided.
In the control unit, the stress generated between the substrate and the above-mentioned pedestal due to the operation of the lifter and the adsorption state detecting unit is set to be equal to or less than the maximum static friction force between the substrate and the pedestal. A processing apparatus that adjusts the temperature difference between the substrate and the above-mentioned pedestal and controls the holding of the substrate on the above-mentioned pedestal. The processing device according to claim 1, wherein the adsorption state detection unit is a torque meter that measures torque in the lifter. The above-mentioned pedestal has an electrostatic chuck that attracts and holds the substrate on the pedestal by applying a voltage.
The processing device according to claim 1, wherein the adsorption state detecting unit is a capacitance meter attached to a voltage supply line to the electrostatic chuck. The above-mentioned pedestal has an electrostatic chuck that attracts and holds the substrate on the pedestal by applying a voltage.
The processing device according to claim 1, wherein the adsorption state detection unit is a galvanometer attached to a voltage supply line to the electrostatic chuck. The processing apparatus according to any one of claims 1 to 4, wherein a heat transfer gas is supplied between the substrate and the above-mentioned table in a state where the substrate is placed. A substrate holding method for holding a substrate in a processing apparatus including a chamber and a mounting table provided inside the chamber on which the substrate is placed.
When the substrate is carried into the chamber and the substrate is placed on the mounting table, the stress generated between the substrate and the mounting table is the maximum rest between the substrate and the mounting table. A substrate holding method in which the temperature difference between the substrate and the above-mentioned table is adjusted so as to be equal to or less than the frictional force, and the substrate is held by the above-mentioned table. A substrate holding method for holding a substrate in a processing apparatus including a chamber and a mounting table provided inside the chamber on which the substrate is placed.
When performing a plurality of processes having different set temperatures in the chamber, the stress generated between the substrate and the above-mentioned pedestal between the plurality of processes is the maximum static friction force between the substrate and the pedestal. A substrate holding method in which the temperature difference between the substrate and the above-mentioned table is adjusted so as to be as follows, and the substrate is held on the above-mentioned table.

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