Substrate support and substrate processing apparatus

Abstract

To provide a substrate support capable of appropriately adjusting the temperature of a substrate by means of a heat transfer medium flowing through a channel formed in a base.SOLUTION: A substrate support that supports a substrate includes a conductive base portion inside which a flow path is formed in which a temperature control fluid of the substrate flows, an electrostatic adsorption portion disposed on the upper surface of the base portion and having a support surface for the substrate on the upper surface, and a metal joint portion that joins the base portion and the electrostatic adsorption portion to each other, and the base portion includes a body member forming at least a portion of a side surface of the flow path and a bottom surface of the flow path, and a heat transfer member forming the top surface of the flow path and performing heat transfer between the temperature control fluid and the electrostatic adsorption portion.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a substrate support and a substrate processing apparatus.

Background Art

[0002] Patent Document 1 discloses a substrate processing apparatus including a base provided therein with a flow path for a refrigerant extending to an inlet and an outlet, and a mounting table having an electrostatic chuck provided on an upper surface of the base via an adhesive and having a heater provided therein or on a lower surface thereof.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The technology according to the present disclosure provides a substrate support that can appropriately adjust the temperature of a substrate by a heat transfer medium flowing through a flow path formed in a base.

Means for Solving the Problems

[0005] One aspect of the present disclosure is a substrate support for supporting a substrate, including a conductive base portion having a flow path formed therein through which a temperature control fluid for the substrate flows, an electrostatic adsorption portion disposed on an upper surface of the base portion and having an upper surface as a support surface for the substrate, and a metal bonding portion that mutually bonds the base portion and the electrostatic adsorption portion. The base portion includes a main body member that forms at least a part of a side surface of the flow path and a bottom surface of the flow path, and a heat transfer member that forms a top surface of the flow path and performs heat transfer between the temperature control fluid and the electrostatic adsorption portion.

Effects of the Invention

[0006] According to the present disclosure, a substrate support capable of appropriately adjusting the substrate temperature by a heat transfer fluid flowing through a flow path formed in a base can be provided.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0008] In the manufacturing process of semiconductor devices, an etching process is performed on an etching target layer (for example, a silicon-containing film) formed by laminating on the surface of a semiconductor substrate (hereinafter simply referred to as "substrate") using a mask layer (for example, a resist film) on which a pattern is previously formed as a mask. This etching process is generally performed in a plasma processing apparatus including a substrate support that adsorbs and holds a substrate using electrostatic force.

[0009] Patent Document 1 discloses a substrate processing apparatus including such a substrate support (mounting table). The substrate support described in Patent Document 1 is formed by bonding a base in which a flow path for a refrigerant is formed and an electrostatic chuck provided with a heater for heating the substrate via an adhesive.

[0010] By the way, in recent plasma processing apparatuses, as the aforementioned etching process, a 3D NAND HARC (High Aspect Ratio Contact) process (hereinafter simply referred to as the "HARC process") of deeply digging holes in a substrate formed by stacking may be performed. However, in such a HARC process, while there is a requirement to appropriately form deep holes by increasing the RF (Radio Frequency) power, there is a risk that the holes cannot be appropriately formed due to the increase in the temperature of the substrate caused by the increase in the RF power. For example, the holes formed on the substrate may be blocked due to the increase in the temperature of the substrate, and thus there is a risk that the holes cannot be appropriately dug deeper.

[0011] Here, as a countermeasure method for suppressing the blockage of holes and appropriately performing the HARC process, for example, keeping the substrate to be processed below a desired temperature, that is, appropriately cooling the substrate, can be considered.

[0012] Cooling of the substrate supported by the substrate support is generally performed by a refrigerant flowing through a flow path formed inside the base of the substrate support, as disclosed in Patent Document 1. However, when the base having the flow path and the electrostatic chuck for supporting the substrate are joined via an adhesive, as in the substrate support (mounting table) disclosed in Patent Document 1, the substrate may not be appropriately cooled. Specifically, as the adhesive for joining the base and the electrostatic chuck, an adhesive made of a resin material having a large thermal resistance (hereinafter referred to as a "resin adhesive") is often used, and there is a risk that the heat transfer from the refrigerant to the substrate is inhibited by the resin adhesive, so that the substrate cannot be appropriately cooled.

[0013] Therefore, as a result of intensive studies by the present inventors, it has been found that by joining a base on which a flow path is formed and an electrostatic chuck that supports a substrate using a metal solder with low thermal resistance instead of adhesion with the above-described resin adhesive, heat conduction can be promoted and the substrate can be appropriately cooled. However, on the other hand, since the base and the electrostatic chuck are generally composed of members with different linear expansion coefficients, there is a concern that these bases and electrostatic chucks may be damaged due to the thermal stress generated during the metal joining.

[0014] The technology according to the present disclosure has been made in view of the above circumstances, and provides a substrate support that can appropriately cool a substrate by a heat transfer fluid flowing through a flow path formed in a base. Hereinafter, a plasma processing system as a substrate processing apparatus according to the present embodiment will be described with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

[0015] <Plasma Processing Apparatus> First, the plasma processing system according to the present embodiment will be described. FIG. 1 is a longitudinal sectional view showing an outline of the configuration of the plasma processing system according to the present embodiment.

[0016] The plasma processing system includes a capacitively coupled plasma processing apparatus 1 and a control unit 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. Further, the plasma processing apparatus 1 includes a substrate support 11 and a gas introduction unit. The substrate support 11 is disposed inside the plasma processing chamber 10. 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 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. Inside the plasma processing chamber 10, a plasma processing space 10s defined by the shower head 13, the side wall 10a of the plasma processing chamber 10, and the substrate support 11 is formed. The plasma processing chamber 10 has at least one gas supply port for supplying at least one processing gas to the plasma processing space 10s and at least one gas discharge port for discharging gas from the plasma processing space 10s. The side wall 10a is grounded. The shower head 13 and the substrate support 11 are electrically insulated from the plasma processing chamber 10.

[0017] The substrate support 11 includes a main body member 111 and a ring assembly 112. The upper surface of the main body member 111 has a central region 111a (substrate support surface) for supporting a substrate (wafer) W and an annular region 111b (ring support surface) for supporting the ring assembly 112. The annular region 111b surrounds the central region 111a in a plan view. The ring assembly 112 includes one or more annular members, and at least one of the one or more annular members is an edge ring.

[0018] As shown in FIG. 2, in one embodiment, the main body member 111 includes a base 113 and an electrostatic chuck 114. The base 113 and the electrostatic chuck 114 are laminated and joined via a metal bonding layer 115.

[0019] In one embodiment, the base 113 includes a main body member 113a and a heat transfer member 113b. The main body member 113a and the heat transfer member 113b are laminated and joined via an adhesive member 113c.

[0020] The main body member 113a is made of a conductive member such as an Al alloy, for example. The conductive member of the main body member 113a functions as a lower electrode. A flow path C is formed on the upper surface of the main body member 113a, which is the surface on the side to which the heat transfer member 113b is joined. In other words, the main body member 113a has an uneven shape in which the flow path C is formed in a cross-sectional view. A heat transfer medium (temperature control fluid) from a chiller unit (not shown) is circulated and supplied to the flow path C. By circulating the heat transfer medium through the flow path C, the ring assembly 112, the electrostatic chuck 114 described later, and the substrate W are adjusted to a desired temperature. As the heat transfer medium, for example, a refrigerant such as cooling water can be used.

[0021] In FIG. 2, the case where the flow path C is formed below the central region 111a (substrate W) in the main body member 113a is illustrated as an example, but the flow path C may be further formed below the annular region 111b corresponding to the ring assembly 112.

[0022] The heat transfer member 113b is made of a conductive member such as a composite material of Al and Si or a composite material of Al and SiC (hereinafter, these may be collectively referred to as an "Al-based composite material") in some cases. More specifically, the heat transfer member 113b is made of a conductive member having a linear expansion coefficient similar to that of the electrostatic chuck 114 described later. The heat transfer member 113b is formed, for example, in a disk shape having substantially the same diameter as the main body member 113a, and is joined to the upper surface of the main body member 113a so as to close the flow path C formed in the main body member 113a from above. In other words, the heat transfer member 113b can function as the top surface of the flow path C formed in the main body member 113a.

[0023] The adhesive member 113c joins the main body member 113a and the heat transfer member 113b. The material of the adhesive member 113c is not particularly limited, but an adhesive having a large thermal resistance, such as the above-described resin adhesive, can be used, for example.

[0024] Further, in one embodiment, a metal contact band 113d for electrically connecting the base body member 113a and the heat transfer member 113b is provided on the base 113. The contact band 113d can be formed of, for example, at least one of a composite material of Ti and Al, stainless steel, or BeCu.

[0025] The electrostatic chuck 114 is joined to the upper surface of the base 113 (more specifically, the heat transfer member 113b) via a metal bonding layer 115 described later. The upper surface of the electrostatic chuck 114 has the aforementioned central region 111a and annular region 111b. Inside the electrostatic chuck 114, a first electrode 114a for adsorbing and holding the substrate W and a second electrode 114b for adsorbing and holding the ring assembly 112 are provided. The electrostatic chuck 114 is configured by sandwiching the first electrode 114a and the second electrode 114b between a pair of dielectric films made of a dielectric such as ceramics.

[0026] In FIG. 2, the case where the central region 111a for holding the substrate W on the upper surface and the annular region 111b for holding the ring assembly 112 on the upper surface in the electrostatic chuck 114 are integrally formed is illustrated as an example. However, the configuration of the electrostatic chuck 114 is not limited to this, and the central region 111a and the annular region 111b of the electrostatic chuck 114 may be configured independently. By configuring the central region 111a and the annular region 111b independently in this way, the temperature adjustment of the substrate W and the temperature adjustment of the ring assembly 112 can be thermally separated and performed independently.

[0027] The metal bonding layer 115 joins the heat transfer member 113b of the base 113 and the electrostatic chuck 114. As the metal bonding layer 115, a material with a low thermal resistance (high thermal conductivity), such as a metal solder like Al solder or Ag solder, can be selected so that heat transfer between the heat transfer member 113b and the electrostatic chuck 114 is appropriately performed.

[0028] Although illustration is omitted, the substrate support 11 may be further provided with a heating module such as a heater for heating at least one of the ring assembly 112, the electrostatic chuck 114, and the substrate W. The heater as the heating module may be provided, for example, below the first electrode 114a and / or the second electrode 114b inside the electrostatic chuck 114. Further, the substrate support 11 may include a heat transfer gas supply unit configured to supply a heat transfer gas (backside gas) between the back surface of the substrate W and the upper surface of the electrostatic chuck 114.

[0029] The shower head 13 is configured to introduce at least one process 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 a plurality of gas introduction ports 13c. The process gas supplied from the gas supply unit 20 to the gas supply port 13a passes through the gas diffusion chamber 13b and is introduced into the plasma processing space 10s from the plurality of gas introduction ports 13c. Further, the shower head 13 includes a conductive member. The conductive member of the shower head 13 functions as an upper electrode. Note that the gas introduction unit may include one or more side gas injectors (SGI) attached to one or more openings formed in the side wall 10a in addition to the shower head 13.

[0030] The gas supply unit 20 may include at least one gas source 21 and at least one flow controller 22. In one embodiment, the gas supply unit 20 is configured to supply at least one process gas from the corresponding gas source 21 to the shower head 13 via the corresponding flow controller 22. Each flow controller 22 may include, for example, a mass flow controller or a pressure-controlled flow controller. Further, the gas supply unit 20 may include one or more flow modulation devices for modulating or pulsing the flow rate of at least one process gas.

[0031] The power supply 30 includes an RF power supply 31 coupled to the plasma processing chamber 10 via at least one impedance matching circuit. The RF power supply 31 is configured to supply at least one RF signal (RF power), such as a source RF signal and a bias RF signal, to the conductive member (lower electrode) of the substrate support 11 and / or the conductive member (upper electrode) of the shower head 13. Thereby, plasma is formed from at least one processing gas supplied to the plasma processing space 10s. Accordingly, the RF power supply 31 can function as at least a part of a plasma generation unit configured to generate plasma from one or more processing gases in the plasma processing chamber 10. Also, by supplying a bias RF signal to the lower electrode, a bias potential is generated on the substrate W, and the ion component in the formed plasma can be drawn into the substrate W.

[0032] In one embodiment, the RF power supply 31 includes a first RF generation unit 31a and a second RF generation unit 31b. The first RF generation unit 31a is coupled to the lower electrode and / or the upper electrode 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 generation 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 lower electrode and / or the upper electrode. The second RF generation unit 31b is coupled to the lower electrode 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 frequency lower than that of 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 generation unit 31b may be configured to generate a plurality of bias RF signals having different frequencies. The generated one or more bias RF signals are supplied to the lower electrode. Also, in various embodiments, at least one of the source RF signal and the bias RF signal may be pulsed.

[0033] In addition, the power supply 30 may include a DC power supply 32 coupled to the plasma processing chamber 10. The DC power supply 32 includes a first DC generation unit 32a and a second DC generation unit 32b. In one embodiment, the first DC generation unit 32a is connected to the lower electrode and configured to generate a first DC signal. The generated first bias DC signal is applied to the lower electrode. In one embodiment, the first DC signal may be applied to other electrodes such as the adsorption electrode in the electrostatic chuck 114. In one embodiment, the second DC generation unit 32b is connected to the upper electrode and configured to generate a second DC signal. The generated second DC signal is applied to the upper electrode. In various embodiments, at least one of the first and second DC signals may be pulsed. Note that the first and second DC generation units 32a and 32b may be provided in addition to the RF power supply 31, or the first DC generation unit 32a may be provided in place of the second RF generation unit 31b.

[0034] The exhaust system 40 can be connected to, for example, a gas outlet 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 internal pressure of the plasma processing space 10s is adjusted by the pressure regulating valve. The vacuum pump may include a turbo molecular pump, a dry pump, or a combination thereof.

[0035] The control unit 2 processes computer-executable instructions that cause the plasma processing apparatus 1 to execute various processes described in the present disclosure. The control unit 2 may be configured to control each element of the plasma processing apparatus 1 to execute the various processes described herein. In one embodiment, 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 RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a combination thereof. The communication interface 2a3 may communicate with the plasma processing apparatus 1 via a communication line such as a LAN (Local Area Network).

[0036] As described above, various exemplary embodiments have been described. However, the present invention is not limited to the above-described exemplary embodiments, and various additions, omissions, substitutions, and changes may be made. Also, it is possible to form other embodiments by combining elements in different embodiments.

[0037] <Method for Processing a Substrate by a Plasma Processing Apparatus> Next, an example of a method for processing a substrate W in the plasma processing apparatus 1 configured as described above will be described. In the plasma processing apparatus 1, an etching process (for example, a HARC process) is performed on the substrate W.

[0038] First, the substrate W is carried into the interior of the plasma processing chamber 10 and placed on the electrostatic chuck 114 of the substrate support 11. Next, a voltage is applied to the suction electrode of the electrostatic chuck 114, whereby the substrate W is adsorbed and held by the electrostatic chuck 114 by electrostatic force.

[0039] When the substrate W is adsorbed and held by the electrostatic chuck 114, next, the inside of the plasma processing chamber 10 is decompressed to a predetermined degree of vacuum. Next, a processing gas is supplied from the gas supply unit 20 to the plasma processing space 10s through the shower head 13. Further, source RF power for plasma generation is supplied from the first RF generation unit 31a to the lower electrode, and thereby, the processing gas is excited to generate plasma. At this time, bias RF power may be supplied from the second RF generation unit 31b. Then, in the plasma processing space 10s, an etching process is performed on the substrate W by the action of the generated plasma.

[0040] When ending the etching process, the supply of the source RF power from the first RF generation unit 31a and the supply of the processing gas from the gas supply unit 20 are stopped. When bias RF power has been supplied during the etching process, the supply of the bias RF power is also stopped.

[0041] Next, the adsorption and holding of the substrate W by the electrostatic chuck 114 is stopped, and the substrate W after the etching process and the electrostatic chuck 114 are discharged. Then, the substrate W is detached from the electrostatic chuck 114, and the substrate W is carried out of the plasma processing apparatus 1. Thus, a series of etching processes is completed.

[0042] <Method for cooling a substrate supported by a substrate support> FIG. 3 is a longitudinal sectional view showing an example of the configuration of a conventional substrate support 200 provided in, for example, a substrate processing apparatus disclosed in Patent Document 1. In the following description, elements having the same configuration as the substrate support 11 according to the technology of the present disclosure are denoted by the same reference numerals, and detailed description thereof is omitted.

[0043] As shown in FIG. 3, the conventional substrate support 200 includes an electrostatic chuck 114 and a base 201. The electrostatic chuck 114 and the base 201 are laminated and joined via an adhesive 202.

[0044] The electrostatic chuck 114 has the same configuration as the electrostatic chuck 114 used for the substrate support 11 according to the present embodiment shown in FIG. 2. That is, for example, the first electrode 114a and the second electrode 114b are sandwiched between insulating materials made of an insulating material such as ceramic. Further, the substrate W and the ring assembly 112 are adsorbed and held on the upper surface of the electrostatic chuck 114.

[0045] The base 201 is made of a conductive member such as an Al alloy, for example. The conductive member of the base 201 functions as a lower electrode. A flow path C is formed in the base 201.

[0046] The adhesive 202 joins the electrostatic chuck 114 and the base 201. As described above, generally, a resin adhesive having a large thermal resistance (low thermal conductivity) is used as the adhesive 202.

[0047] Here, when the substrate W is supported by the conventional substrate support 200 configured as described above and the HARC process as an etching process is performed, there is a possibility that holes cannot be appropriately deep-etched in the substrate W. Specifically, as described above, when RF is applied to the lower electrode at high power, the substrate W adsorbed and held by the electrostatic chuck 114 becomes hot due to this, and as a result, the formed holes may be blocked and etching may not proceed.

[0048] As a method for suppressing such blockage of the holes, it is conceivable to cool the substrate W held by the electrostatic chuck 114 by heat transfer from the refrigerant flowing through the flow path C formed in the base 201. However, when the base 201 in which the flow path C is formed and the electrostatic chuck 114 that adsorbs and holds the substrate W are joined by an adhesive 202 that is a resin adhesive having a large thermal resistance (thermal conductivity: 0.2 to 0.3 W / mK), heat transfer from the refrigerant to the substrate W may be inhibited by the resin adhesive, and there is a possibility that the substrate W cannot be appropriately cooled.

[0049] Therefore, in the substrate support 11 according to the present embodiment, as shown in FIG. 2, the base 113 in which the flow path C is formed and the electrostatic chuck 114 are joined by a metal bonding layer 115 having a small thermal resistance, such as a metal solder (thermal conductivity: 100 to 160 W / mK) such as Al solder or Ag solder. Further, in the substrate support 11 according to the present embodiment, the base 113 in which the flow path C is formed is divided into a main body member 113a that forms at least a part of the bottom surface and the side surface of the flow path C and is composed of a conductive member, and a heat transfer member 113b that forms the top surface of the flow path C and is composed of a conductive member having a linear expansion coefficient similar to that of the electrostatic chuck 114. The main body member 113a and the heat transfer member 113b are adhered by a resin adhesive having a small thermal resistance in one example.

[0050] When the base 113 and the electrostatic chuck 114 are joined by a metal solder (metal bonding layer 115) as in the present embodiment, the base 113 and the electrostatic chuck 114 are heated by the melted metal solder. At this time, if the difference in the linear expansion coefficient between the base 113 and the electrostatic chuck 114 is large, the base 113 or the electrostatic chuck 114 may be damaged due to the residual stress caused by the thermal stress generated during joining.

[0051] For example, as in the conventional substrate support 200 shown in FIG. 3, when a base 201 made of an aluminum alloy (linear expansion coefficient: about 23e-6 / °C) and an electrostatic chuck 114 made of ceramics (linear expansion coefficient: about 7 to 8e-6 / °C) are joined by a metal solder, since the linear expansion amount of the base 201 is larger than that of the electrostatic chuck 114, if the metal bonding layer (metal solder) cannot sufficiently relieve the residual stress, the electrostatic chuck 114 will be damaged.

[0052] Therefore, in the present embodiment, as described above, the heat transfer member 113b of the base 113 that is directly joined to at least the electrostatic chuck 114 is formed of a conductive member having a coefficient of linear expansion similar to that of the electrostatic chuck 114 (ceramics), for example, an Al-based composite material (coefficient of linear expansion: about 7 to 9e-6 / °C). In this way, by reducing the difference in the coefficient of linear expansion between the electrostatic chuck 114 and the heat transfer member 113b joined via the metal bonding layer 115, the thermal stress generated when the electrostatic chuck 114 and the base 113 are joined can be reduced. That is, the residual stress generated between the electrostatic chuck 114 and the heat transfer member 113b can be reduced, thereby appropriately suppressing damage to the base 113 and the electrostatic chuck 114 due to the difference in the coefficient of linear expansion.

[0053] According to the present embodiment, the base 113 is configured by being divided into the main body member 113a and the heat transfer member 113b in this way. By reducing the difference in the coefficient of linear expansion between the heat transfer member 113b directly joined to the electrostatic chuck 114 and the electrostatic chuck 114 to be joined, the base 113 and the electrostatic chuck 114 can be appropriately joined using a metal brazing material, and the substrate support 11 according to the present embodiment can be formed.

[0054] And according to the present embodiment, by joining the base 113 and the electrostatic chuck 114 with a metal brazing material (metal bonding layer 115) in this way, heat transfer from the refrigerant flowing through the flow path C to the electrostatic chuck 114 (substrate W) is promoted as compared with the conventional case, and the substrate W can be appropriately cooled via the metal bonding layer 115. That is, it becomes possible to achieve both an increase in the RF high power applied to the lower electrode and a reduction in the temperature of the substrate W.

[0055] Also at this time, in addition to directly contacting the refrigerant by functioning as the top surface of the flow path C, the heat transfer member 113b is joined to the main body member 113a having a large heat capacity by a resin adhesive having a small thermal resistance. Thereby, heat transfer from the refrigerant to the heat transfer member 113b is directly performed, and heat transfer from the heat transfer member 113b to the main body member 113a is suppressed, so that heat transfer from the refrigerant to the electrostatic chuck 114 (substrate W) can be performed more appropriately.

[0056] Note that the conductive member constituting the heat transfer member 113b is not limited to the Al-based composite material as shown in the present embodiment, and any conductive member can be arbitrarily selected as long as it has a small coefficient of linear expansion difference from the electrostatic chuck 114 (ceramics). Specifically, as a result of intensive studies by the present inventors, for example, by forming the heat transfer member 113b of a conductive member having a coefficient of linear expansion difference of 3e-6 / °C or less from the electrostatic chuck 114 (ceramics), it is possible to appropriately suppress damage caused by the coefficient of linear expansion difference. Examples of other conductive members having a coefficient of linear expansion difference of 3e-6 / °C or less from ceramics include Ti alloys (coefficient of linear expansion difference: 2e-6 / °C).

[0057] Here, even when the heat transfer member 113b is formed of a conductive member having a small coefficient of linear expansion difference from the electrostatic chuck 114 as described above, if a metal solder having a high bonding temperature between the heat transfer member 113b and the electrostatic chuck 114 is selected for bonding, there is a risk of damaging the electrostatic chuck 114 due to the thermal stress generated during bonding. Specifically, even when the coefficient of linear expansion difference between the heat transfer member 113b and the electrostatic chuck 114 is small, when the bonding temperature is high, the difference in the amount of expansion and contraction deformation during bonding becomes large, which may cause damage to the electrostatic chuck 114.

[0058] Therefore, in the present embodiment, in order to suppress damage to the electrostatic chuck 114 caused by the thermal stress generated during such bonding, it is desirable to select a metal solder used as the metal bonding layer 115 having a bonding temperature of, for example, 700°C or less. By selecting a metal solder having a bonding temperature below the desired temperature in this way, the difference in the amount of expansion and contraction deformation generated during bonding can be reduced, that is, damage to the electrostatic chuck 114 can be suppressed and the base 113 (heat transfer member 113b) and the electrostatic chuck 114 can be appropriately bonded.

[0059] FIG. 4 is a table showing the relationship between the above base 113 and the electrostatic chuck 114, specifically, the correspondence between the coefficient of linear expansion difference and the bonding temperature of the metal solder.

[0060] As described above, in the substrate support 11 according to the present embodiment, the base 113 in which the flow path C is formed is formed of a conductive member having a linear expansion coefficient difference of 3e-6 / °C or less from the electrostatic chuck 114, and it is desirable to join the base 113 to the electrostatic chuck 114 with a metal solder having a high thermal conductivity and a joining temperature of 700°C or less. In such a case, for example, as shown in FIG. 4, at least the heat transfer member 113b of the base 113 is formed of an Al-based composite material (linear expansion coefficient difference: 1e-6 / °C), and it is desirable to use Al solder or Ag solder (joining temperature: 500 to 700°C) as the metal joining layer 115.

[0061] <Effects of the substrate support according to the present disclosure> As described above, according to the substrate support 11 according to the present embodiment, the base 113 in which the flow path C is formed and the electrostatic chuck 114 that adsorbs and holds the substrate W are joined by the metal joining layer 115 having a small thermal resistance. At this time, the upper surface side of the base 113 joined to the electrostatic chuck 114 (the heat transfer member 113b in the embodiment) is configured by using a conductive member having a small linear expansion coefficient difference from the electrostatic chuck 114, preferably 3e-6 / °C or less, so that breakage of the base 113 and the electrostatic chuck 114 due to thermal stress during metal joining can be appropriately suppressed.

[0062] And by joining the base 113 and the electrostatic chuck 114 in this way, that is, joining them with the metal joining layer 115 having a small thermal resistance, heat transfer from the refrigerant to the substrate W is appropriately performed, so that the substrate W can be appropriately cooled. Also at this time, the heat transfer member 113b directly joined to the electrostatic chuck 114 functions as the top surface of the flow path C, and the heat transfer member 113b and the main body member 113a are joined by a resin adhesive having a large thermal resistance, so that heat transfer from the refrigerant to the substrate W can be performed more appropriately.

[0063] In addition, in this embodiment, since heat transfer between the refrigerant and the substrate W can be appropriately performed, for example, even when performing a HARC process as an etching process, the substrate W can be appropriately cooled. In other words, in the substrate support 11 according to this embodiment, it is possible to achieve both RF high-power and low-temperature of the substrate W, and holes can be appropriately formed deeply in the substrate W.

[0064] Also, even when RF is applied at high power during the HARC process and the heat transfer member 113b and the electrostatic chuck 114 are heated, the difference in the amount of expansion and contraction deformation between the heat transfer member 113b and the electrostatic chuck 114, that is, the generated residual stress can be reduced. And, since the generated residual stress becomes small in this way, breakage due to the difference in the linear expansion coefficients of the base 113 and the electrostatic chuck 114 during the HARC process is appropriately suppressed. In other words, breakage of the base 113 and the electrostatic chuck 114 can be suppressed not only during metal bonding but also during the HARC process.

[0065] Furthermore, according to this embodiment, as the metal bonding layer 115 that joins the base 113 and the electrostatic chuck 114, a metal solder (for example, Al solder or Ag solder) with a bonding temperature of 700°C or lower is selected. Thereby, the thermal stress generated during the joining of the base 113 and the electrostatic chuck 114 can be reduced, that is, breakage of the electrostatic chuck 114 due to thermal stress can be appropriately suppressed, and the base 113 and the electrostatic chuck 114 can be appropriately joined.

[0066] Also, according to the substrate support 11 according to this embodiment, by joining the base 113 and the electrostatic chuck 114 to each other with the metal bonding layer 115 in this way, the thermal responsiveness of the substrate support 11 and the substrate W during the etching process is improved. That is, for example, since the thermal followability during a hybrid operation in which RF is alternately applied at high power and low power during the etching process can be improved, such RF power switching can be repeated in a shorter time.

[0067] In the above embodiments, the base 113 is configured by joining a main body member 113a having a concavo-convex shape in cross-sectional view and a heat transfer member 113b having a substantially flat plate shape. However, the configuration of the base 113 is not limited to this.

[0068] FIG. 5 is a longitudinal sectional view showing an outline of the configuration of a substrate support according to the second embodiment.

[0069] As shown in FIG. 5, in the substrate support 211 according to the second embodiment, the base 213 and the electrostatic chuck 114 are joined to each other via a metal bonding layer 115. Further, in the base 213, for example, a main body member 213a having a concavo-convex shape facing upward in cross-sectional view and a heat transfer member 213b having a concavo-convex shape facing downward in cross-sectional view are connected to each other via an adhesive member 213c.

[0070] The main body member 213a is made of a conductive member such as an Al alloy and functions as a lower electrode. Further, as described above, the main body member 213a has a concavo-convex shape facing upward in cross-sectional view. The concavo-convex shape forms a flow path C by being arranged to face the concavo-convex shape formed in the heat transfer member 213b described later. In other words, the concavo-convex shape formed in the main body member 213a defines at least a part of the bottom surface of the flow path C and the side surface of the flow path C.

[0071] The heat transfer member 213b is made of a conductive member (for example, an Al-based composite material) having a coefficient of linear expansion similar to that of the electrostatic chuck 114. Further, as described above, the heat transfer member 213b has a concavo-convex shape facing downward in cross-sectional view. The concavo-convex shape forms a flow path C by being arranged to face the concavo-convex shape formed in the main body member 213a. In other words, the concavo-convex shape formed in the heat transfer member 213b defines at least a part of the top surface of the flow path C and the side surface of the flow path C.

[0072] The adhesive member 213c joins the main body member 213a and the heat transfer member 213b. As the adhesive member 213c, for example, a resin adhesive having a large thermal resistance can be used.

[0073] According to the substrate support 211 according to the second embodiment, by forming the heat transfer member 213b connected via the electrostatic chuck 114 and the metal bonding layer 115 to have an uneven shape in cross-section, the contact area between the heat transfer member 213b and the flow path C can be increased. Thereby, the amount of heat transfer from the refrigerant to the heat transfer member 213b, in other words, the cooling capacity of the electrostatic chuck 114 (substrate W) by the heat transfer member 213b can be improved, and the substrate W can be cooled more appropriately.

[0074] Also, in the present embodiment, similar to the substrate support 11 according to the first embodiment, the main body member 213a and the heat transfer member 213b are bonded by a resin adhesive having a large thermal resistance. Thereby, heat transfer between the heat transfer member 213b and the main body member 213a having a large heat capacity can be suppressed, that is, the substrate W can be cooled more appropriately.

[0075] Subsequently, FIG. 6 is a longitudinal sectional view showing an outline of the configuration of the substrate support according to the third embodiment.

[0076] As shown in FIG. 6, in the substrate support 311 according to the third embodiment, the base 313 and the electrostatic chuck 114 are joined to each other via the metal bonding layer 115. Further, in the base 313, for example, a main body member 313a having an uneven shape upward in cross-section and a heat transfer member 313b having a substantially disc shape are joined via an adhesive member 313c.

[0077] The main body member 313a is made of a conductive member (for example, an Al-based composite material) having a coefficient of linear expansion similar to that of the electrostatic chuck 114, for example, and functions as a lower electrode. Further, as described above, the main body member 313a has an uneven shape upward in cross-section. The uneven shape forms the flow path C by being blocked by the heat transfer member 313b described later. In other words, the uneven shape formed in the main body member 313a defines the bottom surface of the flow path C and the side surface of the flow path C.

[0078] The heat transfer member 313b is made of a conductive member (e.g., an Al-based composite material) having a coefficient of linear expansion similar to that of the electrostatic chuck 114, for example. The heat transfer member 313b is laminated and disposed on the main body member 313a so as to close the uneven shape formed on the main body member 313a. In other words, the heat transfer member 313b defines the top surface of the flow path C.

[0079] The bonding member 313c bonds the main body member 313a and the heat transfer member 313b. As the bonding member 313c, for example, a resin adhesive having a large thermal resistance can be used.

[0080] According to the substrate support 311 according to the third embodiment, as described above, the main body member 313a and the heat transfer member 313b forming the base 313 are each made of the same conductive material. Thereby, even when the main body member 313a and the heat transfer member 313b are each heated to a high temperature by applying RF at high power in, for example, the HARC process, a difference in the amount of expansion and contraction deformation is suppressed between the main body member 313a and the heat transfer member 313b. That is, breakage of the base 313 during the HARC process is suppressed, and the substrate W can be more stably adsorbed and held by the substrate support 311.

[0081] As described above in the first to third embodiments, by configuring at least the heat transfer member joined via the electrostatic chuck 114 and the metal bonding layer 115 with a conductive member having a coefficient of linear expansion similar to that of the electrostatic chuck 114, damage to the substrate support due to residual stress generated due to the difference in the coefficient of linear expansion between the electrostatic chuck 114 and the heat transfer member can be suppressed.

[0082] On the other hand, as shown in the first to third embodiments, the main body member disposed below the heat transfer member can be configured by any member such as an Al-based composite material having a coefficient of linear expansion similar to that of the electrostatic chuck 114 or an Al alloy used in a conventional substrate support. For example, by configuring the main body member with an Al-based composite material having a linear expansion coefficient similar to that of the electrostatic chuck 114, damage to the base due to high temperature in the HARC process can be suppressed. Also, for example, Al alloys and the like conventionally used for substrate supports are members that are inexpensive and easy to process compared to Al-based composite materials. That is, by configuring the main body member with an Al alloy or the like, the flow path C can be easily formed in the main body member, and the cost of forming the substrate support can be reduced.

[0083] Note that, as shown in the first to third embodiments above, the main body member and the heat transfer member constituting the base are joined by, for example, a resin adhesive having a large thermal resistance. However, depending on the type of refrigerant flowing through the flow path C, the resin adhesive may be soluble in the refrigerant. In such a case, as shown in FIGS. 2, 5, and 6, when the resin adhesive is provided facing the flow path C, when the resin adhesive comes into contact with the refrigerant, the resin adhesive may be damaged when the refrigerant is passed through, and there is a risk that the main body member and the heat transfer member may peel off.

[0084] Therefore, in order to suppress damage to the resin adhesive by the refrigerant in this way, for example, as shown in FIG. 7, a sealing member 113e (e.g., an O-ring or the like) for preventing contact between the refrigerant and the adhesive member 113c (resin adhesive) may be provided on the contact surface between the adhesive member 113c and the flow path C. By providing the sealing member 113e in this way to prevent contact between the refrigerant and the adhesive member 113c, damage to the adhesive member 113c can be appropriately suppressed.

[0085] Also, for example, as shown in FIG. 8, in order to suppress damage to the resin adhesive by the refrigerant, a weir 113f for reducing the flow velocity of the refrigerant flowing through the flow path C may be formed in the vicinity of the contact surface between the adhesive member 113c and the flow path C. The shape and arrangement of the weir 113f are not particularly limited, but for example, it is provided on the upstream side in the flow direction of the refrigerant in the flow path C with respect to the adhesive member 113c to reduce the flow velocity of the refrigerant coming into contact with the adhesive member 113c. As a result, the dissolution amount of the adhesive member 113c with respect to the refrigerant per unit time / per unit flow rate can be reduced, that is, damage to the adhesive member 113c can be suppressed.

[0086] Note that either one of the sealing member 113e shown in FIG. 7 and the weir 113f shown in FIG. 8 may be provided, or both of them may be provided. Specifically, for the flow rate C formed on one substrate support, either one of them may be provided as shown in FIGS. 7 and 8, or both the sealing member 113e and the weir 113f may be provided (illustration omitted).

[0087] In the above embodiments, the case where the base and the electrostatic chuck are joined via a metal bonding layer which is a metal solder such as Al solder or Ag solder has been described as an example. However, the joining member between the base and the electrostatic chuck is not limited to such a metal solder. Specifically, it is sufficient that the base and the electrostatic chuck are joined using a joining member having a higher thermal conductivity than at least the resin adhesive (thermal conductivity: 0.2 to 0.3 W / mK) that has joined the base and the electrostatic chuck in the conventional substrate support. As a result, the amount of heat transfer from the refrigerant to the substrate W can be increased as compared with at least the conventional substrate support, that is, at least the substrate W can be appropriately cooled.

[0088] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The above embodiments may be omitted, substituted, or changed in various forms without departing from the scope and gist of the appended claims.

Explanation of Reference Numerals

[0089] 11 Substrate support 113 Base 113a Body member 113b Heat transfer member 114 Electrostatic chuck 115 Metal bonding layer C Flow path W substrate

Claims

1. A substrate support for supporting a substrate, comprising: a conductive base portion having a flow path formed therein through which a temperature control fluid for the substrate flows; an electrostatic adsorption portion disposed on the upper surface of the base portion and having a support surface for the substrate on the upper surface; a metal bonding portion that joins the base portion and the electrostatic adsorption portion to each other; wherein the base portion includes a main body member forming at least a part of a side surface of the flow path and a bottom surface of the flow path; a heat transfer member forming a top surface of the flow path and performing heat transfer between the temperature control fluid and the electrostatic adsorption portion; an adhesive made of a resin material that joins the main body member and the heat transfer member to each other; and is a substrate support.

2. The substrate support according to claim 1, further comprising a sealing member for preventing contact between the temperature control fluid and the resin material.

3. The substrate support according to claim 1 or 2, wherein a weir for reducing a contact flow rate of the temperature control fluid flowing through the inside of the flow path with respect to the resin material is formed inside the flow path.

4. The substrate support according to any one of claims 1 to 3, wherein the heat transfer member is composed of a member having a linear expansion coefficient difference of 3e-6 or less with respect to the electrostatic adsorption portion.

5. The substrate support according to claim 4, wherein the heat transfer member is composed of at least one of a composite material of Al and Si, a composite material of Al and SiC, or a Ti alloy.

6. The substrate support according to any one of claims 1 to 5, wherein the main body member is composed of the same member as the heat transfer member.

7. The substrate support according to any one of claims 1 to 5, wherein the main body member is composed of an Al alloy.

8. The substrate support according to any one of claims 1 to 7, wherein the metal bonding portion is a metal solder having a bonding temperature of 700°C or less.

9. The substrate support according to claim 8, wherein the metal solder is at least one of an Al solder or an Ag solder.

10. The substrate support according to any one of claims 1 to 9, further comprising a contact band for electrically connecting the main body member and the heat transfer member.

11. A substrate processing apparatus for processing a substrate, comprising: a processing chamber that defines a processing space for the substrate; the substrate support according to any one of claims 1 to 10 disposed inside the processing space; a gas supply unit that supplies a processing gas to the processing space; and a plasma generation unit that generates plasma in the processing space by the processing gas.

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