Method for predicting the state of an electrostatic chuck

Abstract

To predict aging deterioration of an electrostatic chuck.SOLUTION: There is provided a method for predicting a state of an electrostatic chuck comprising: a step for performing first plasma processing while an electrostatic chuck provided inside of a vacuum processing container and constituted so as to attract and hold a substrate by electrostatic forces and is not mounted on the substrate; a step for acquiring the processing time of the first plasma processing; a step for performing second plasma processing which is different from the first plasma processing while the substrate is placed on the electrostatic chuck and the substrate is attracted and held to the electrostatic chuck; a step for acquiring a sliding distance between the electrostatic chuck and the substrate and a sliding pressure between the electrostatic chuck and the substrate, for each processing step of the second plasma processing, the second plasma processing including one or a plurality of processing steps; and a process of predicting the state of the electrostatic chuck on the basis of the acquired processing time and the sliding distance and sliding pressure for each processing step.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a method for predicting the state of an electrostatic chuck. [Background technology]

[0002] The miniaturization of semiconductor devices has led to stricter requirements for uniformity of temperature within the surface of a substrate. For example, Patent Document 1 discloses an electrostatic chuck that can make the temperature within the surface of a substrate uniform by adjusting the number of multiple dot-shaped protrusions per unit area formed on the substrate support surface. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-257495 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides techniques that can predict degradation of an electrostatic chuck over time. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, there is provided a method for predicting a state of an electrostatic chuck, comprising the steps of: performing a first plasma processing step with no substrate placed on an electrostatic chuck provided in a vacuum processing vessel and configured to electrostatically attract and hold a substrate; acquiring a processing time for the first plasma processing step; placing the substrate on the electrostatic chuck and performing a second plasma processing step different from the first plasma processing step with the substrate being attracted and held by the electrostatic chuck; the second plasma processing step having one or more processing steps, acquiring a sliding distance between the electrostatic chuck and the substrate and a sliding pressure between the electrostatic chuck and the substrate for each processing step of the second plasma processing step; and predicting a state of the electrostatic chuck based on the acquired processing time and the sliding distance and the sliding pressure for each processing step. Effect of the Invention

[0006] According to one aspect, it is possible to predict the deterioration of an electrostatic chuck over time. [Brief description of the drawings]

[0007] [Figure 1] 1 illustrates a plasma processing system according to an embodiment; [Diagram 2] 1 is a schematic cross-sectional view showing a plasma processing apparatus according to an embodiment; [Diagram 3] FIG. 2 is a diagram showing an example of a pattern configuration of a substrate support surface of an electrostatic chuck. [Figure 4] FIG. 1 is a diagram showing an example of the surface roughness of a new electrostatic chuck and a used electrostatic chuck. [Diagram 5] 4 is a diagram for explaining a sliding distance Lp and a sliding pressure Pp according to the embodiment. FIG. [Figure 6] 4 is a flowchart showing a method for predicting a state of an electrostatic chuck according to the first embodiment. [Figure 7] 10 is a flowchart showing an information collecting method according to a second embodiment. [Figure 8] 10 is a flowchart showing a method for predicting a state of an electrostatic chuck according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0009] [Plasma processing system] In one embodiment, the plasma processing system shown in FIG. 1 includes a plasma processing apparatus 1 and a control unit 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a substrate support unit 11, and a plasma generation unit 12. The plasma processing chamber 10 is an example of a vacuum processing vessel, and has a plasma processing space therein. The plasma processing chamber 10 also has at least one gas supply port for supplying at least one processing gas to the plasma processing space, and at least one gas exhaust port for exhausting gas from the plasma processing space. The gas supply port is connected to a gas supply unit 20, which will be described later, and the gas exhaust port is connected to an exhaust system 40, which will be described later. The substrate support unit 11 is disposed in the plasma processing space, and has a substrate support surface for supporting a substrate.

[0010] The plasma generating unit 12 is configured to generate plasma from at least one processing gas supplied into the plasma processing space. The plasma formed in the plasma processing space may be a capacitively coupled plasma (CCP), an inductively coupled plasma (ICP), an electron-cyclotron-resonance plasma (ECR plasma), a helicon wave plasma (HWP), a surface wave plasma (SWP), or the like. Also, various types of plasma generating units may be used, including an alternating current (AC) plasma generating unit and a direct current (DC) plasma generating unit. In one embodiment, the AC signal (AC power) used in the AC plasma generating unit has a frequency in the range of 100 kHz to 10 GHz. Thus, the AC signal includes a radio frequency (RF) signal and a microwave signal. In one embodiment, the RF signal has a frequency in the range of 200 kHz to 150 MHz.

[0011] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to perform various steps described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to perform various steps described herein. In one embodiment, a part or all of the control unit 2 may be included in the plasma processing apparatus 1. The control unit 2 may include, for example, a computer 2a. The computer 2a may include, for example, a processing unit (CPU: Central Processing Unit) 2a1, a storage unit 2a2, and a communication interface 2a3. The processing unit 2a1 may be configured to perform various control operations based on a program stored in the storage unit 2a2. The storage unit 2a2 may include a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), a solid state drive (SSD), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a local area network (LAN).

[0012] Next, a configuration example of a capacitively coupled plasma processing apparatus 1 will be described as an example of the plasma processing apparatus 1 with reference to FIG. 2. The plasma processing apparatus 1 includes a plasma processing chamber 10, a gas supply unit 20, a power supply 30, and an exhaust system 40. The plasma processing apparatus 1 also includes a substrate support 11 and a gas introduction unit. The gas introduction unit is configured to introduce at least one processing gas into the plasma processing chamber 10. The gas introduction unit includes a shower head 13. The substrate support 11 is disposed in the plasma processing chamber 10. The shower head 13 is disposed above the substrate support 11. In one embodiment, the shower head 13 constitutes at least a part of the ceiling of the plasma processing chamber 10. The plasma processing chamber 10 has a plasma processing space 10s defined by the shower head 13, a sidewall 10a of the plasma processing chamber 10, and the substrate support 11. The sidewall 10a is grounded. The shower head 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10 housing.

[0013] The substrate support 11 includes a main body 111, an electrostatic chuck 113, and a ring assembly 112. The electrostatic chuck 113 has an intermediate region (substrate support surface) 111a for supporting a substrate (wafer) W, and an annular region (ring support surface) 111b for supporting the ring assembly 112. The annular region 111b of the electrostatic chuck 113 surrounds the intermediate region 111a of the electrostatic chuck 113 in a plan view. The substrate W is disposed on the intermediate region 111a of the electrostatic chuck 113, and the ring assembly 112 is disposed on the annular region 111b of the electrostatic chuck 113 so as to surround the substrate W on the intermediate region 111a of the electrostatic chuck 113. In one embodiment, the main body 111 serves as a base for supporting the electrostatic chuck 113. The main body 111 includes a conductive member. The conductive member of the main body 111 functions as a lower electrode. The electrostatic chuck 113 is disposed on the main body 111. The upper surface of the electrostatic chuck 113 has a substrate support surface 111a. The electrostatic chuck 113 is configured to attract and hold the substrate W on the substrate support surface 111a by electrostatic force. Specifically, a desired DC voltage HV is applied to the chuck electrode 113a, and the substrate W is attracted and held on the substrate support surface 111a by electrostatic force.

[0014] The ring assembly 112 includes one or more annular members. At least one of the one or more annular members is an edge ring. Although not shown, the substrate support 11 may include a temperature adjustment module configured to adjust at least one of the electrostatic chuck 113, the ring assembly 112, and the substrate W to a target temperature. The temperature adjustment module may include a heater, a heat transfer medium, a flow path, or a combination thereof. A heat transfer fluid such as brine or gas flows through the flow path. The substrate support 11 also includes a heat transfer gas supply unit configured to supply a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a.

[0015] The shower head 13 is configured to introduce at least one processing gas from the gas supply unit 20 into the plasma processing space 10s. The shower head 13 has at least one gas supply port 13a, at least one gas diffusion chamber 13b, and multiple gas inlets 13c. The processing gas supplied to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the multiple gas inlets 13c. The shower head 13 also includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. In addition to the shower head 13, the gas introduction unit may include one or more side gas injectors (SGIs) attached to one or more openings formed in the side wall 10a.

[0016] The gas supply 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply 20 is configured to supply at least one process gas from a respective gas source 21 through a respective flow controller 22 to the showerhead 13. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Additionally, the gas supply 20 may include at least one flow modulation device to modulate or pulse a flow rate of the at least one process gas.

[0017] The power source 30 includes an RF power source 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power source 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to a conductive member of the substrate support 11 and / or a conductive member of the showerhead 13. This causes a plasma to be formed from at least one processing gas supplied to the plasma processing space 10s. Thus, the RF power source 31 can function as at least a part of the plasma generating unit 12. In addition, by supplying a bias RF signal to the conductive member of the substrate support 11, a bias potential is generated on the substrate W, and ion components in the formed plasma can be attracted to the substrate W.

[0018] In one embodiment, the RF power supply 31 includes a first RF generating unit 31a and a second RF generating unit 31b. The first RF generating unit 31a is coupled to the conductive member of the substrate support 11 and / or the conductive member of the shower head 13 via at least one impedance matching circuit, and is configured to generate a source RF signal (source RF power) for plasma generation. In one embodiment, the source RF signal has a frequency in the range of 13 MHz to 150 MHz. In one embodiment, the first RF generating unit 31a may be configured to generate a plurality of source RF signals having different frequencies. The generated one or more source RF signals are supplied to the conductive member of the substrate support 11 and / or the conductive member of the shower head 13. The second RF generating unit 31b is coupled to the conductive member of the substrate support 11 via at least one impedance matching circuit, and is configured to generate a bias RF signal (bias RF power). In one embodiment, the bias RF signal has a lower frequency than the source RF signal. In one embodiment, the bias RF signal has a frequency in the range of 400 kHz to 13.56 MHz. In one embodiment, the second RF generator 31b may be configured to generate multiple bias RF signals having different frequencies. The generated bias RF signal or signals are provided to the conductive members of the substrate support 11. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0019] The power supply 30 may also include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generator 32a and a second DC generator 32b. In one embodiment, the first DC generator 32a is connected to a conductive member of the substrate support 11 and configured to generate a first DC signal. The generated first DC signal is applied to the conductive member of the substrate support 11. In one embodiment, the first DC signal may be applied to another electrode, such as an electrode in an electrostatic chuck. In one embodiment, the second DC generator 32b is connected to a conductive member of the showerhead 13 and configured to generate a second DC signal. The generated second DC signal is applied to the conductive member of the showerhead 13. In various embodiments, the first and second DC signals may be pulsed. The first and second DC generating units 32a, 32b may be provided in addition to the RF power supply 31, or the first DC generating unit 32a may be provided in place of the second RF generating unit 31b.

[0020] The exhaust system 40 may be connected to, for example, a gas exhaust port 10e provided at the bottom of the plasma processing chamber 10. The exhaust system 40 may include a pressure regulating valve and a vacuum pump. The pressure in the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbomolecular pump, a dry pump, or a combination thereof.

[0021] [Electrostatic chuck] Next, the pattern configuration of the substrate support surface 111a of the electrostatic chuck 113 will be described with reference to FIG. 3. FIG. 3(a) is a top view of the substrate support surface 111a of the electrostatic chuck 113. FIG. 3(b) is a view showing a cross section taken along line AA of FIG. 3(a). The substrate support surface 111a is formed, for example, in a circular shape having a diameter smaller than that of the substrate W to be placed thereon. As a result, when the substrate W is placed on the substrate support surface 111a, the outer periphery of the substrate W protrudes outward from the end of the substrate support surface 111a. The substrate support surface 111a of the electrostatic chuck 113 has a ring-shaped protrusion (hereinafter referred to as a seal portion 26) that annularly surrounds the outermost periphery, and a dot pattern of multiple cylindrical protrusions 25a, 25b, and 25c located inside the seal portion 26. The seal portion 26 and the multiple protrusions 25a, 25b, 25c have flat upper surfaces at the same height, and come into contact with the substrate W when the substrate W is placed on it. Therefore, the substrate W is supported by the seal portion 26 of the substrate supporting surface 111a and the multiple protrusions 25a, 25b, 25c. Hereinafter, the protrusions 25a, 25b, 25c are also collectively referred to as protrusions 25.

[0022] The substrate supporting surface 111a is divided into a central region Ra, an intermediate region Rb, and an outer circumferential region Rc. The central region Ra is located in a range from the center of the substrate W to 80% of the radius of the substrate W from the center to the outer circumferential region. The intermediate region Rb is located in a range from 80% to 90% of the radius of the substrate W when viewed from the center of the substrate W. The outer circumferential region Rc is located in a range from 90% to 98% of the radius of the substrate W when viewed from the center of the substrate W.

[0023] A plurality of convex portions 25a are evenly arranged in the central region Ra of the substrate support surface 111a. A plurality of convex portions 25b are evenly arranged in the middle region Rb of the substrate support surface 111a so that the density of the convex portions 25 is lower than that in the central region Ra. A plurality of convex portions 25c are evenly arranged in the outer peripheral region Rc of the substrate support surface 111a so that the density of the convex portions 25 is higher than that in the middle region Rb. A ring-shaped seal portion 26 is arranged on the outermost periphery. As shown in FIG. 3, the convex portions 25 in the outer peripheral region Rc are dense, the convex portions 25b in the middle region Rb are sparse, and the convex portions 25a in the central region are dense, so that the in-plane temperature of the substrate W can be made uniform. In addition, the outermost ring-shaped seal portion 26 seals the heat transfer gas such as helium gas supplied between the substrate support surface 111a and the substrate W, and the amount of heat transfer gas leaking from between the substrate support surface 111a and the substrate W can be suppressed.

[0024] However, if the surface roughness RA of the convex portions 25a, 25b, and 25c of the substrate supporting surface 111a and the seal portion 26 deteriorates, the heat transfer gas leaks between the substrate supporting surface 111a and the substrate W, reducing the heat transfer effect. In particular, if the surface roughness RA of the seal portion 26 deteriorates, the amount of leakage of the heat transfer gas increases.

[0025] 4 is a graph showing an example of the surface roughness RA of a new electrostatic chuck (New) and a used electrostatic chuck (Old). The horizontal axis indicates the radial position (central region Ra, intermediate region Rb, outer peripheral region Rc) of the substrate support surface 111a, and the vertical axis indicates the surface roughness RA. The used electrostatic chuck (Old) has a worsened surface roughness RA overall compared to the new electrostatic chuck (New). In particular, the used electrostatic chuck (Old) has a noticeable worsening of the surface roughness RA in the outer peripheral region Rc.

[0026] When the surface roughness RA in the outer circumferential region Rc deteriorates, the amount of leakage of the heat transfer gas increases, which leads to an uneven temperature distribution on the substrate support surface 111a, which leads to a deterioration in the product yield and a decrease in productivity. Therefore, when the amount of leakage of the heat transfer gas reaches a certain level or more, it is determined that the electrostatic chuck 113 has reached the end of its life, and the electrostatic chuck 113 needs to be replaced.

[0027] Therefore, in the method for predicting the state of an electrostatic chuck according to the present embodiment, the amount of deterioration of the electrostatic chuck 113 over time is calculated, and the life of the electrostatic chuck 113 is predicted based on the calculation result. The substrate support surface 111a of the electrostatic chuck 113 changes over time due to (a) surface roughening during cleaning, and (b) smoothing caused by sliding between the substrate W and the electrostatic chuck 113 during substrate processing. In (a), the substrate support surface 111a of the electrostatic chuck 113 is exposed to plasma by waferless dry cleaning performed using plasma in a state in which the substrate W is not placed on the electrostatic chuck 113, and thus the surface roughness of the substrate support surface 111a occurs. The waferless dry cleaning (WLDC) process is an example of a first plasma processing process performed in a state in which the substrate W is not placed on the electrostatic chuck 113. The longer the processing time of the waferless dry cleaning, the greater the surface roughness of the electrostatic chuck 113.

[0028] In (b), due to the difference in linear thermal expansion coefficient between the substrate W made of silicon and the electrostatic chuck 113 made of ceramic, the difference in expansion and contraction between the substrate W and the electrostatic chuck 113 in response to temperature changes causes friction between the substrate W and the electrostatic chuck 113. The greater the friction between the substrate W and the electrostatic chuck 113, the more the surface roughness RA of the electrostatic chuck 113 is alleviated by the friction, and the surface roughness of the electrostatic chuck 113 becomes smaller.

[0029] From the above, the amount of deterioration over time can be calculated from the integrated amount of surface roughness of the electrostatic chuck 113 caused by (a) waferless dry cleaning and (b) rubbing between the substrate W and the electrostatic chuck 113. The state of the surface roughness RA of the outermost sealing portion 26 affects the life of the electrostatic chuck 113. Therefore, the amount of leakage of the heat transfer gas can be predicted by estimating the degree of damage to the sealing portion 26, and the life of the electrostatic chuck 113 can be determined based on the prediction result.

[0030] (Calculation of sliding distance Lp) In order to calculate the amount of deterioration (damage) of the electrostatic chuck 113 over time, the following equation (1) is used, which is a numerical representation of (a) and (b).

[0031]

number

[0032] Lp indicates the distance over which the electrostatic chuck 113 and the substrate W rub against each other. In other words, the sliding distance Lp indicates the distance over which the electrostatic chuck 113 and the substrate W rub against each other when they expand and contract in response to temperature changes, since they have different linear expansion coefficients. For example, assume that the substrate W expands by a distance Lp relatively outward from the electrostatic chuck 113 in response to temperature changes from the state shown in FIG. 5(a) to the state shown in FIG. 5(b). The distance at this time is the distance over which the electrostatic chuck 113 and the substrate W rub against each other. In this specification, this distance is defined as the sliding distance Lp.

[0033] Pp indicates the pressure difference between when the substrate W is attracted to the electrostatic chuck 113 and when it is not attracted. The pressure applied to the substrate W is the pressure difference between the pressure when attracted, which is determined by the DC voltage HV applied to the chuck electrode 113a, and the pressure when not attracted when the DC voltage HV is turned off, as shown by the arrows in Fig. 5(b). In this specification, this pressure is defined as the sliding pressure Pp. In the following description, the applied DC voltage HV is assumed to be constant, but the DC voltage HV may be variable.

[0034] According to formula (1), the larger the sliding distance Lp and the sliding pressure Pp, the more the surface of the electrostatic chuck 113 is polished, and it is possible to smooth the surface of the electrostatic chuck 113 that has become rough due to friction with the substrate W. In other words, it can be seen that the larger the sliding distance Lp and the sliding pressure Pp, the more the roughness of the surface of the electrostatic chuck 113 is alleviated, and the less damage (amount of deterioration over time) is caused.

[0035] In formula (1), the multiplication value of the sliding distance Lp and the sliding pressure Pp is calculated for each processing step indicated by Σ (Full Step), and the multiplication values ​​of the sliding distance Lp and the sliding pressure Pp calculated for all steps are added. The sliding distance Lp and the sliding pressure Pp are calculated in a second plasma processing different from the first plasma processing, which is an example of waferless dry cleaning. For example, an etching process or a film formation process is given as an example of the second plasma processing. When the second plasma processing is composed of one or more processing steps, a value is calculated by multiplying the multiplication value of Lp and Pp by a correction coefficient R in each processing step, and the calculation of this multiplication value is repeated for the number of steps, and the multiplication values ​​(Lp×Pp×R) of all steps are added.

[0036] In formula (1), R is a correction coefficient, which is set to a constant. C indicates the number of substrates W processed per hour. Therefore, the value in the brackets {} in formula (1) indicates the damage per substrate W. The damage per fixed period of time (amount of deterioration over time) can be calculated by multiplying the value in the brackets {} in formula (1) by the number of substrates W processed per hour, C.

[0037] The sliding pressure Pp has a different value depending on the dot pattern. In this disclosure, the sliding pressure Pp when the dot pattern shown in FIG. 3 has a dense outer peripheral region Rc, a sparse intermediate region Rb, and a dense central region is used in a simulation for calculating the amount of deterioration over time using the formula (1) described below.

[0038] (Calculation of sliding distance Lp) As shown in formula (2), the sliding distance Lp is the absolute value of the difference between the sliding distance Lesc of the electrostatic chuck 113 and the sliding distance Lwafer of the substrate W between processing steps included in the substrate processing, such as an etching process, which is an example of the second plasma processing. Specifically, the sliding distance Lp is calculated using formulas (2), (3), and (4).

[0039] Lp = |Lesc-Lwafer| (2) Lesc=ΔTesc×r×CTEesc...(3) Lwafer=ΔTwafer×r×CTEwafer...(4) In equation (3), ΔTesc is the temperature difference of the electrostatic chuck 113 between processing steps, r is the radius of the electrostatic chuck 113, and CTEesc is the thermal expansion coefficient of the electrostatic chuck 113. In equation (4), ΔTwafer is the temperature difference of the substrate W between processing steps, and CTEwafer is the thermal expansion coefficient of the substrate W. The temperature difference ΔTesc is the difference between the temperature of the electrostatic chuck 113 measured in the previous processing step and the temperature of the electrostatic chuck 113 measured in the current processing step. The temperature difference ΔTwafer is the difference between the substrate temperature measured in the previous processing step and the substrate temperature measured in the current processing step. The diameter of the electrostatic chuck 113 (twice the radius r) is the inner diameter of the seal portion 26.

[0040] (Calculation of sliding pressure Pp) The sliding pressure Pp is calculated using equation (5).

[0041] Pp=(F HV -F BP ) / S sB (5) F HV indicates an electrostatic adsorption force, that is, a force with which the substrate W is pressed against the electrostatic chuck 113 by an electrostatic force generated by applying a DC voltage HV to the chuck electrode 113a. The value of the DC voltage HV applied to the chuck electrode 113a may be constant or variable.

[0042] F BP is a force that is generated in a direction lifting the substrate W from the electrostatic chuck 113 by supplying a heat transfer gas between the back surface of the substrate W and the substrate support surface 111a. sB is the surface area of ​​the upper surface of the seal portion 26.

[0043] Therefore, from equation (5), it is understood that the sliding pressure Pp can be calculated from the difference between the force pressing the substrate W against the electrostatic chuck 113 and the force lifting the substrate W.

[0044] There is a correlation between the arrangement of the protrusions 25 and the sliding pressure Pp. As shown in Fig. 3, when the arrangement of the protrusions 25 is denser in the outer peripheral region Rc than in the intermediate region Rb, as the usage time of the electrostatic chuck 113 increases, the sliding pressure Pp decreases near the seal portion 26 in the outermost peripheral region. It can be seen from formula (1) that as the sliding pressure Pp decreases, damage to the electrostatic chuck 113 increases.

[0045] A simulation was performed in which a second process (substrate processing) was performed based on multiple types of process recipes, and the amount of deterioration over time of the electrostatic chuck 113 (Damage in formula (1)) was calculated using formulas (1) to (5). Changing the DC voltage HV changes the value of the sliding pressure Pp. In the simulation, the DC voltage HV was set to several values. As a result of the simulation, various values ​​of the amount of deterioration over time of the electrostatic chuck 113 were calculated according to the type of process recipe and the DC voltage HV. It was confirmed that the amount of deterioration over time of the electrostatic chuck 113 obtained by the simulation was almost the same as the amount of deterioration over time of the electrostatic chuck 113 obtained as a result of actually performing the second process (substrate processing) under the same conditions as the simulation conditions.

[0046] As described above, the inventors have found that the amount of deterioration over time of the electrostatic chuck 113 can be predicted from the surface roughness of the electrostatic chuck 113 and the degree of wear of the electrostatic chuck 113, and have proven that the amount of deterioration over time of the electrostatic chuck 113 can be calculated from formula (1). The inventors expressed the surface roughness of the electrostatic chuck 113 as the processing time Tw of the waferless dry cleaning, and determined that the longer the processing time Tw, the greater the amount of deterioration over time of the electrostatic chuck 113. The inventors also expressed the degree of wear of the electrostatic chuck 113 as a value (Lp×Pp×R) obtained by multiplying the product of the sliding distance Lp and the sliding pressure Pp by a correction coefficient R, and determined that the greater the degree of wear, the smaller the amount of deterioration over time.

[0047] From the above, the amount of deterioration over time of the electrostatic chuck 113 can be calculated using formula (1), and the state of the electrostatic chuck 113 can be predicted based on the calculated amount of deterioration over time. That is, the amount of deterioration over time of the electrostatic chuck 113 is calculated using the processing time Tw of the waferless dry cleaning, the sliding distance Lp, the sliding pressure Pp, and the correction coefficient R, and the state of the electrostatic chuck 113 is predicted based on the calculation result, thereby predicting the life of the electrostatic chuck 113. For example, when the amount of deterioration over time is equal to or greater than a preset threshold, it is determined that the deterioration of the electrostatic chuck 113 has exceeded an allowable range, and a warning is issued, so that replacement of the electrostatic chuck 113 can be promoted or the time for replacement can be notified.

[0048] [First embodiment] Hereinafter, the method for predicting the state of an electrostatic chuck according to the first embodiment will be described with reference to Fig. 6. Fig. 6 is a flowchart showing the method for predicting the state of an electrostatic chuck according to the first embodiment. This process is executed by a processing unit 2a1 of a control unit 2.

[0049] When this process is started, the control unit 2 supplies a cleaning gas into the plasma processing chamber 10, supplies an RF signal from the RF power supply 31, and executes waferless dry cleaning (WLDC) (step S1). The control unit 2 obtains the processing time Tw of the waferless dry cleaning from a timing means such as a timer (step S2).

[0050] Next, the control unit 2 prepares the substrate W on the electrostatic chuck 113, and applies a DC voltage HV to the chuck electrode 113a to attract and hold the substrate W on the electrostatic chuck 113 (step S3). Next, the control unit 2 supplies a processing gas into the plasma processing chamber 10, supplies an RF signal from the RF power supply 31, and performs plasma processing of the substrate W for each processing step (step S4).

[0051] Next, the control unit 2 obtains the sliding distance Lp between the substrate W and the electrostatic chuck 113 (step S5), and obtains the sliding pressure Pp between the substrate W and the electrostatic chuck 113 (step S6). In this way, the control unit 2 obtains the sliding distance Lp and the sliding pressure Pp measured during the plasma processing of the substrate in real time. However, this is not limited to the above, and the control unit 2 may obtain the temperature difference ΔTesc and the temperature difference ΔTwafer between the processing steps in step S5, and calculate the sliding distance Lp by substituting ΔTesc and the temperature difference ΔTwafer, the radius r of the electrostatic chuck 113, CTEesc, and CTEwafer into the formulas (2) to (4). Furthermore, the control unit 2 calculates the electrostatic adsorption force F HV , the force applied to the substrate during dechucking F BP and add F to equation (5). HV , F BP , the surface area S of the upper surface of the seal portion 26 sB The sliding pressure Pp may be calculated by substituting the above.

[0052] Next, the control unit 2 determines whether all the processing steps of the plasma processing have been performed (step S7). If the control unit 2 determines that all the processing steps of the plasma processing have not been performed, it repeats the processing of steps S4 to S7 until all the processing steps of the plasma processing have been performed. If the control unit 2 determines that all the processing steps of the plasma processing have been performed, it reads from the storage unit 2a2 equation (1) which is a formula for calculating the amount of deterioration over time of the electrostatic chuck 113 (step S8). Next, the control unit 2 substitutes the acquired processing time Tw, sliding distance Lp, and sliding pressure Pp into equation (1) to calculate the amount of deterioration over time of the electrostatic chuck 113 (step S9).

[0053] Next, the control unit 2 determines whether the calculated deterioration amount over time of the electrostatic chuck 113 is equal to or greater than a preset threshold, and if so, issues a warning (step S10), and ends this process. An example of issuing a warning is to notify by display and / or sound the time to replace the electrostatic chuck 113. If the deterioration amount over time is smaller than the preset threshold, it is determined that the deterioration amount over time of the electrostatic chuck 113 is within an allowable range and no warning is necessary, and ends this process.

[0054] As described above, according to the method for predicting the state of an electrostatic chuck according to the first embodiment, the state of the electrostatic chuck 113 can be predicted based on the processing time Tw of the waferless dry cleaning (WLDC) and the sliding distance Lp and sliding pressure Pp in the plasma processing of the substrate. That is, the surface roughness RA of the electrostatic chuck 113 is monitored based on the processing time Tw, and the degree of wear of the electrostatic chuck 113 is monitored based on the sliding distance Lp and the sliding pressure Pp. The processing time Tw is a factor that accelerates the deterioration of the electrostatic chuck 113 over time, and the sliding distance Lp and the sliding pressure Pp are factors that improve the deterioration of the electrostatic chuck 113 over time. Therefore, the amount of deterioration of the electrostatic chuck 113 over time can be calculated based on the processing time Tw, the sliding distance Lp, and the sliding pressure Pp, and the life of the electrostatic chuck 113 can be predicted or the time to replace the electrostatic chuck 113 can be notified.

[0055] [Second embodiment] Next, a method for predicting the state of an electrostatic chuck according to a second embodiment will be described with reference to Figs. 7 and 8. Fig. 7 is a flowchart showing an information collecting method according to the second embodiment. Fig. 8 is a flowchart showing a method for predicting the state of an electrostatic chuck according to the second embodiment. Note that the steps in Figs. 7 and 8 are given the same step numbers as those in Fig. 6 when they are the same processes. This process is executed by a processing unit 2a1 of a control unit 2.

[0056] The method for predicting the state of an electrostatic chuck according to the second embodiment differs from the method for predicting the state of an electrostatic chuck according to the first embodiment in that steps S1 and S2 in FIG. 6 are not executed consecutively with the processing from step S3 onward in FIG. 6 as a series of processing, but are executed at separate times.

[0057] That is, in the second embodiment, the processes corresponding to steps S1 and S2 in Fig. 6 are performed in steps S1 and S20 shown in Fig. 7. Specifically, when this process is started, the control unit 2 supplies a cleaning gas into the plasma processing chamber 10, supplies an RF signal from the RF power supply 31, and performs waferless dry cleaning (step S1). The control unit 2 stores the processing time Tw of the waferless dry cleaning in the storage unit 2a2 (step S20), and ends this process. This allows information on the processing time Tw to be collected.

[0058] The method for predicting a state of an electrostatic chuck according to the second embodiment shown in Fig. 8 is started without interlocking with the timing of collecting information on the processing time Tw shown in Fig. 7. However, this process is started after information on the processing time Tw is stored in the storage unit 2a2. When this process is started, the control unit performs the same processes of steps S3 to S7 as those of the first embodiment.

[0059] When the control unit 2 determines in step S7 that all the processing steps of the plasma processing have been executed, the control unit 2 reads from the storage unit 2a2 the formula (1) for calculating the amount of deterioration over time of the electrostatic chuck 113 (step S8). In addition, the control unit 2 acquires the processing time Tw from the storage unit 2a2 (step S21).

[0060] According to the method for predicting the state of an electrostatic chuck according to the second embodiment, the acquired processing time Tw, sliding distance Lp, and sliding pressure Pp are substituted into equation (1) to calculate the amount of deterioration over time of the electrostatic chuck 113 (step S9). The subsequent processing steps are the same as those in the first embodiment, and therefore will not be described.

[0061] As described above, according to the method for predicting the state of an electrostatic chuck according to the second embodiment, it is not necessary to perform waferless dry cleaning and plasma processing of a substrate consecutively, and the time-dependent deterioration of the electrostatic chuck can be predicted using the processing time Tw of the waferless dry cleaning stored in advance, thereby making it possible to predict the life and replacement time of the electrostatic chuck.

[0062] The electrostatic chuck state prediction method according to the embodiment disclosed herein should be considered as illustrative and not restrictive in all respects. The embodiments can be modified and improved in various forms without departing from the scope and spirit of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent.

[0063] The plasma processing apparatus of the present disclosure can be applied to any type of apparatus, including Atomic Layer Deposition (ALD) apparatus, Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

[0064] Furthermore, although a plasma processing apparatus has been given as an example of a substrate processing apparatus, the substrate processing apparatus may be an apparatus that performs a predetermined process on a substrate (e.g., a film formation process, an etching process, etc.) and is not limited to a plasma processing apparatus. [Explanation of symbols]

[0065] 1. Plasma processing equipment 2. Control section 2a Computer 2a1 Processing section 2a2 Storage section 2a3 Communication Interface 10 Plasma Processing Chamber 11 Substrate support 13. Shower Head 21 Gas Source 20 Gas supply section 25a, 25b, 25c, 25 convex part 26 Seal part 30 power supply 31 RF power supply 31a First RF generation unit 31b Second RF generation unit 32a First DC generation unit 32b Second DC generation section 40 Exhaust system 111 Main body 111a Board support surface 112 Ring Assembly 113 Electrostatic Chuck

Claims

1. performing a first plasma processing in a state where the substrate is not placed on an electrostatic chuck that is provided in a vacuum processing vessel and configured to attract and hold the substrate by electrostatic force; acquiring a processing time of the first plasma processing; placing the substrate on the electrostatic chuck, and performing a second plasma treatment different from the first plasma treatment while the substrate is attracted and held by the electrostatic chuck; the second plasma processing includes one or more processing steps, and acquiring a sliding distance between the electrostatic chuck and the substrate and a sliding pressure between the electrostatic chuck and the substrate for each processing step of the second plasma processing; a process of predicting a state of the electrostatic chuck based on the acquired processing time, the sliding distance and the sliding pressure for each processing step; A method for predicting a state of an electrostatic chuck, comprising:

2. 1. A method for monitoring a state of an electrostatic chuck provided in a vacuum processing vessel and configured to attract and hold a substrate by electrostatic force, comprising: performing a first plasma processing operation without placing a substrate on an electrostatic chuck; and monitoring a state of the electrostatic chuck by referring to a storage unit that stores a processing time of the first plasma processing operation in advance, the method comprising the steps of: placing the substrate on the electrostatic chuck, and performing a second plasma treatment different from the first plasma treatment while the substrate is attracted and held by the electrostatic chuck; the second plasma processing includes one or more processing steps, and acquiring a sliding distance between the electrostatic chuck and the substrate and a sliding pressure between the electrostatic chuck and the substrate for each processing step of the second plasma processing; a process of predicting a state of the electrostatic chuck based on a processing time of the first plasma processing and the obtained sliding distance and sliding pressure for each processing step by referring to the storage unit; A method for predicting a state of an electrostatic chuck, comprising:

3. The sliding distance is calculated by the product of a temperature difference between the processing steps, a radius of the electrostatic chuck, and a thermal expansion coefficient of the electrostatic chuck. The state prediction method according to claim 1 or 2.

4. The sliding pressure is calculated based on a pressure difference between when the substrate is attracted to the electrostatic chuck and when the substrate is not attracted to the electrostatic chuck. The state prediction method according to any one of claims 1 to 3.

5. calculating an amount of deterioration of the electrostatic chuck over time based on a processing time of the first plasma processing, the sliding distance, the sliding pressure, and a correction coefficient, and predicting a life of the electrostatic chuck based on a result of the calculation; The state prediction method according to any one of claims 1 to 4.

6. issuing a warning when the amount of deterioration over time exceeds a predetermined threshold; The state prediction method according to claim 5 .

7. The outermost periphery of the electrostatic chuck has a ring-shaped protrusion. The state prediction method according to any one of claims 1 to 6.

8. a plurality of cylindrical protrusions on a substrate support surface of the electrostatic chuck, the cylindrical protrusions being located inside the ring-shaped protrusion; a density of the plurality of protrusions in an outer circumferential region of the electrostatic chuck is higher than a density of the plurality of protrusions in an intermediate region of the electrostatic chuck; The state prediction method according to claim 7.

9. The first plasma treatment is a waferless dry cleaning. The state prediction method according to any one of claims 1 to 8.

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