JP7548665B2 - Mounting table assembly, substrate processing apparatus and substrate processing method - Google Patents

Description

The present disclosure relates to a mounting table assembly, a substrate processing apparatus, and a substrate processing method.

For example, Patent Document 1 discloses a substrate processing apparatus that includes a substrate holder that electrostatically attracts the back surface of a focus ring (edge ring) to a focus ring mounting surface, and a heat transfer gas supply unit that supplies a heat transfer gas to the back surface of the focus ring.

JP 2015-062237 A

This disclosure provides a technology that reduces the amount of heat transfer gas leaking when the edge ring is attached.

According to one aspect of the present disclosure, a mounting table assembly for mounting a substrate is provided, the mounting table assembly comprising a base, an electrostatic chuck disposed on the base, and a plurality of edge rings disposed around the substrate, the edge ring being composed of a plurality of edge ring pieces divided in the circumferential direction, the electrostatic chuck having a substrate adsorption portion for adsorbing the substrate and an edge ring adsorption portion for adsorbing the plurality of edge ring pieces, and the edge ring adsorption portion each having a heat transfer gas groove through which a heat transfer gas is supplied to each of the regions to which the plurality of edge rings are adsorbed.

This disclosure provides a technology that reduces the amount of heat transfer gas leaking when the edge ring is attached.

FIG. 1 is a cross-sectional view showing a schematic configuration of a substrate processing apparatus according to this embodiment. FIG. 2 is an enlarged cross-sectional view of the periphery of an edge ring of the substrate processing apparatus according to this embodiment. FIG. 3 is a top view of the mounting table assembly of the substrate processing apparatus according to the present embodiment. FIG. 4 is a top view of the electrostatic chuck of the substrate processing apparatus according to the present embodiment. FIG. 5 is a cross-sectional view of the electrostatic chuck of the substrate processing apparatus according to the present embodiment. FIG. 6 is a diagram for explaining the supply of a heat transfer gas to an electrostatic chuck of the substrate processing apparatus according to this embodiment. FIG. 7 is a diagram for explaining pressure control of the heat transfer gas to the electrostatic chuck of the substrate processing apparatus according to this embodiment. FIG. 8 is a diagram illustrating the correlation between the edge ring temperature and the pressure setting value in the substrate processing apparatus according to this embodiment. FIG. 9 is a diagram illustrating an example of the distribution of the etching rate in the substrate processing apparatus according to this embodiment. FIG. 10 is a diagram for explaining the relationship between the pressure of the heat transfer gas on the rear surface of the wafer and the temperature of the wafer. FIG. 11 is a diagram for explaining a substrate processing method in the substrate processing apparatus according to the present embodiment. FIG. 12 is a diagram illustrating the supply of power to the electrostatic chuck of the substrate processing apparatus according to this embodiment. FIG. 13 is a diagram for explaining a substrate processing method in the substrate processing apparatus according to the present embodiment. FIG. 14 is a diagram for explaining the variation rate of the etching rate and the number of processed substrates in the substrate processing apparatus according to this embodiment. FIG. 15 is a cross-sectional view of an end portion of an edge ring of the substrate processing apparatus according to this embodiment. FIG. 16 is a cross-sectional view of an end portion of an edge ring of the substrate processing apparatus according to this embodiment. FIG. 17 is a cross-sectional view of an end portion of an edge ring of the substrate processing apparatus according to this embodiment.

The following describes the embodiments of the present disclosure with reference to the drawings. In this specification and the drawings, the same reference numerals are used to designate substantially identical components, and redundant description will be omitted. For ease of understanding, the scale of each part in the drawings may differ from the actual scale. In directions such as parallel, right angle, orthogonal, horizontal, vertical, up/down, left/right, deviations that do not impair the effects of the embodiment are permitted. The shape of the corners is not limited to right angles, and may be rounded in a bow shape. Parallel, right angle, orthogonal, horizontal, and vertical may include approximately parallel, approximately right angle, approximately orthogonal, approximately horizontal, and approximately vertical.

<Overall configuration of substrate processing apparatus 1>
First, an example of the overall configuration of a substrate processing apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of the substrate processing apparatus 1 according to the present embodiment. In the present embodiment, an example will be described in which the substrate processing apparatus 1 is an RIE (Reactive Ion Etching) type substrate processing apparatus. However, the substrate processing apparatus 1 may be a plasma etching apparatus or a plasma CVD (Chemical Vapor Deposition) apparatus, etc.

In FIG. 1, the substrate processing apparatus 1 has a grounded cylindrical processing vessel 2 made of metal, for example, aluminum or stainless steel, and a disk-shaped mounting table 10 for mounting a substrate W is disposed within the processing vessel 2. The mounting table 10 includes a base 100 and an electrostatic chuck 200. The base 100 functions as a lower electrode. The base 100 is made of, for example, aluminum. The base 100 is supported by a cylindrical support 13 that extends vertically upward from the bottom of the processing vessel 2 via an insulating cylindrical holding member 12.

An exhaust path 14 is formed between the side wall of the processing vessel 2 and the cylindrical support 13, and an annular baffle plate 15 is disposed at the entrance or midway of the exhaust path 14, and an exhaust port 16 is provided at the bottom, to which an exhaust device 18 is connected via an exhaust pipe 17. Here, the exhaust device 18 has a dry pump and a vacuum pump, and reduces the pressure of the processing space in the processing vessel 2 to a predetermined vacuum level. In addition, the exhaust pipe 17 has an automatic pressure control valve (hereinafter referred to as "APC"), which is a variable butterfly valve, and the APC automatically controls the pressure in the processing vessel 2. In addition, a gate valve 20 that opens and closes a transfer port 19 for the substrate W is attached to the side wall of the processing vessel 2.

A radio frequency (RF) power source is connected to the base 100 via a matching unit. In the example shown in FIG. 1, a first radio frequency power source 21a is connected to the base 100 via a matching unit 22a. A second radio frequency power source 21b is connected to the base 100 via a matching unit 22b. The first radio frequency power source 21a supplies radio frequency power for plasma generation of a predetermined frequency (e.g., 40 MHz) to the base 100. The second radio frequency power source 21b supplies radio frequency power for ion attraction of a predetermined frequency (e.g., 400 kHz) lower than that of the first radio frequency power source 21a to the base 100.

A shower head 24, which also functions as an upper electrode, is disposed on the ceiling of the processing vessel 2. This allows high frequency powers of two frequencies to be supplied between the base 100 and the shower head 24 from the first high frequency power source 21a and the second high frequency power source 21b.

An electrostatic chuck 200 is provided on the upper surface of the base 100, which attracts the substrate W by electrostatic attraction. The electrostatic chuck 200 has a disk-shaped substrate attraction portion 200a on which the substrate W is placed, and an annular edge ring attraction portion 200b formed to surround the substrate attraction portion 200a. The substrate attraction portion 200a protrudes upward in the figure relative to the edge ring attraction portion 200b. The upper surface of the substrate attraction portion 200a is a substrate mounting surface 200a1 on which the substrate W is placed. The upper surface of the edge ring attraction portion 200b is an edge ring mounting surface 200b1 on which the edge ring 300 is placed. The edge ring mounting surface 200b1 is configured to mount the edge ring 300 around the substrate mounting surface 200a1. The edge ring 300 is also called a focus ring. As described below, in the substrate processing apparatus 1 of this embodiment, the edge ring 300 is composed of multiple edge ring pieces 301 to 306.

The substrate adsorption unit 200a is formed by sandwiching a substrate adsorption electrode plate 210 made of a conductive film between a pair of dielectric films. A DC power supply 27 is electrically connected to the substrate adsorption electrode plate 210. The edge ring adsorption unit 200b is formed by sandwiching an edge ring adsorption electrode plate 220 made of a conductive film between a pair of dielectric films. A DC power supply 28 is electrically connected to the edge ring adsorption electrode plate 220. As described later, in the substrate processing apparatus 1 of this embodiment, the edge ring adsorption unit 200b is provided with a plurality of edge ring adsorption electrode plates. A DC power supply 28 is connected to each of the plurality of edge ring adsorption electrode plates. In this disclosure, when there is no particular need to distinguish between them, the electrode plates of each edge ring adsorption unit 200b are collectively referred to as edge ring adsorption electrode plates 220.

The combination of the mounting table 10 and the edge ring 300 is sometimes referred to as the mounting table assembly 5.

The DC power supplies 27 and 28 are capable of changing the level and polarity of the DC voltage they supply. The DC power supply 27 applies a DC voltage to the substrate adsorption electrode plate 210 under the control of the control unit 43 described later. The DC power supply 28 applies a DC voltage to the edge ring adsorption electrode plate 220 under the control of the control unit 43. The electrostatic chuck 200 generates an electrostatic force such as a Coulomb force by the voltage applied from the DC power supply 27 to the substrate adsorption electrode plate 210, and adsorbs and holds the substrate W to the electrostatic chuck 200 by the electrostatic force. The electrostatic chuck 200 also generates an electrostatic force such as a Coulomb force by the voltage applied from the DC power supply 28 to the edge ring adsorption electrode plate 220, and adsorbs and holds the edge ring 300 to the electrostatic chuck 200 by the electrostatic force. The DC power supply 28 can apply individual voltages to each of the multiple edge ring adsorption electrode plates.

In the present embodiment, the electrostatic chuck 200 has the substrate adsorption portion 200a and the edge ring adsorption portion 200b integrated together, but the substrate adsorption portion 200a and the edge ring adsorption portion 200b may each be separate electrostatic chucks. That is, the substrate adsorption electrode plate 210 and the edge ring adsorption electrode plate 220 may each be sandwiched between independent dielectric films. In addition, although an example of a monopolar electrode is shown for the edge ring adsorption electrode plate 220 in this embodiment, it may also be a bipolar electrode. In the case of a bipolar electrode, the edge ring 300 can be adsorbed even when plasma is not generated.

Inside the base 100, a flow path 110 is provided that extends, for example, in the circumferential direction. A coolant at a predetermined temperature, for example, cooling water, is circulated and supplied to the flow path 110 from the chiller unit 32 via pipes 33 and 34, and the processing temperature of the substrate W on the electrostatic chuck 200 and the temperature of the edge ring 300 are controlled by the temperature of the coolant. The coolant is an example of a temperature adjustment medium (temperature control medium) that is circulated and supplied to the flow path 110. The temperature control medium not only cools the base 100 and the substrate W, but may also heat them.

The electrostatic chuck 200 is connected to a first heat transfer gas supply unit 35 via a gas supply line 36. The first heat transfer gas supply unit 35 uses the gas supply line 36 to supply a heat transfer gas to a space between the substrate adsorption unit 200a of the electrostatic chuck 200 and the substrate W. The electrostatic chuck 200 is connected to a second heat transfer gas supply unit 45 via a gas supply line 46. The second heat transfer gas supply unit 45 uses the gas supply line 46 to supply a heat transfer gas to a space between the edge ring adsorption unit 200b of the electrostatic chuck 200 and the edge ring 300. As the heat transfer gas, a gas having thermal conductivity, such as He gas, is preferably used. The heat transfer gas is supplied from the second heat transfer gas supply unit 45 corresponding to each of the multiple edge rings.

By supplying a heat transfer gas between the electrostatic chuck 200 and the substrate W, and between the electrostatic chuck 200 and the edge ring 300, the heat input from the plasma to the substrate W or the edge ring 300 can be efficiently transferred to the base 100.

The shower head 24 in the ceiling portion has an electrode plate 37 on the lower surface having a number of gas vent holes 37a, and an electrode support 38 that detachably supports the electrode plate 37. A buffer chamber 39 is provided inside the electrode support 38, and a process gas supply unit 40 is connected to a gas inlet 38a that communicates with the buffer chamber 39 via a gas supply pipe 41.

Each component of the substrate processing apparatus 1 is connected to the control unit 43. For example, the exhaust device 18, the first high frequency power supply 21a, the second high frequency power supply 21b, the matching unit 22a, the matching unit 22b, the DC power supply 27, the DC power supply 28, the chiller unit 32, the first heat transfer gas supply unit 35, the second heat transfer gas supply unit 45, and the process gas supply unit 40 are connected to the control unit 43. The control unit 43 controls each component of the substrate processing apparatus 1.

The control unit 43 includes a central processing unit (CPU) and a storage device such as a memory (not shown), and reads and executes the programs and processing recipes stored in the storage device to perform the desired processing in the substrate processing device 1. The control unit 43 also performs an electrostatic adsorption process to electrostatically adsorb the edge ring 300.

In the substrate processing apparatus 1, first, the gate valve 20 is opened, and the substrate W to be processed is loaded into the processing vessel 2 and placed on the _{electrostatic} chuck 200. Then, in the substrate processing apparatus 1, a processing gas (e.g., a mixed gas consisting of _C4F8 gas, _O2 gas, and Ar gas) is introduced into the processing vessel 2 from the processing gas supply unit 40 at a predetermined flow rate and flow rate ratio, and the pressure in the processing vessel 2 is set to a predetermined value by the exhaust device 18 or the like.

In addition, in the substrate processing apparatus 1, high frequency powers of different frequencies are supplied to the base 100 from the first high frequency power supply 21a and the second high frequency power supply 21b. In addition, in the substrate processing apparatus 1, a DC voltage is applied from the DC power supply 27 to the substrate attracting electrode plate 210 of the electrostatic chuck 200, and the substrate W is attracted to the electrostatic chuck 200. In addition, in the substrate processing apparatus 1, a DC voltage is applied from the DC power supply 28 to the edge ring attracting electrode plate 220 of the electrostatic chuck 200, and the edge ring 300 is attracted to the electrostatic chuck 200. The processing gas discharged from the shower head 24 is turned into plasma, and the substrate W is etched by the radicals and ions in the plasma.

<Adsorption of Edge Ring 300>
The adsorption of the edge ring 300 will be described. FIG. 2 is an enlarged cross-sectional view of the periphery of the edge ring 300 of the substrate processing apparatus 1 according to this embodiment. In the substrate processing apparatus 1 of this embodiment, the edge ring 300 includes a plurality of edge ring pieces 301 to 306 divided in the circumferential direction. The substrate processing apparatus 1 also includes edge ring adsorption electrode plates 221 to 226 corresponding to the edge ring pieces 301 to 306, respectively (see FIGS. 3 and 5). Here, the edge ring piece 301 and the edge ring adsorption electrode plate 221 will be used for the description among the edge ring pieces 301 to 306 and the edge ring adsorption electrode plates 221 to 226 corresponding to the edge ring pieces 301 to 306.

The edge ring piece 301 is attracted to the electrostatic chuck 200 by the edge ring attracting electrode plate 221. The edge ring attracting electrode plate 221 has a power supply section 221a to which a voltage is supplied from the DC power supply 28. The edge ring attracting electrode plate 221 also has a through hole 221b through which the gas supply line 46 passes.

The electrostatic chuck 200 has a heat transfer gas supply hole 231a on the edge ring mounting surface 200b1 through which heat transfer gas is supplied from the gas supply line 46.

The heat transfer gas is supplied from the second heat transfer gas supply unit 45 to the heat transfer gas supply hole 231a via the gas supply line 46. The second heat transfer gas supply unit 45 includes a gas supply source 45a and a pressure control valve 45b1. As described below, the second heat transfer gas supply unit 45 includes pressure control valves 45b1 to 45b6 corresponding to the multiple edge ring pieces 301 to 306, respectively. In FIG. 2, one edge ring piece 301 will be described.

The heat transfer gas supplied to the heat transfer gas supply hole 231a is supplied between the back surface 301c of the edge ring piece 301 and the edge ring mounting surface 200b1 via the heat transfer gas groove 231 (see FIG. 4) provided in the edge ring mounting surface 200b1.

The processing vessel 2 is an example of a processing chamber.

<Edge ring 300 of substrate processing apparatus 1>
FIG. 3 is a top view of the mounting table assembly 5 of the substrate processing apparatus 1 according to this embodiment. The mounting table assembly 5 includes a plurality of edge rings 300 that are mounted on and attracted to the edge ring mounting surface 200b1 of the electrostatic chuck 200. Specifically, the mounting table assembly 5 includes six edge ring pieces 301 to 306. The edge ring pieces 301 to 306 are arranged around the substrate mounting surface 200a1, i.e., the substrate W. The edge ring pieces 301 to 306 each have the same shape. The number of edge ring pieces may be two or more as long as the edge ring mounting surface 200b1 can be entirely covered. From the viewpoints of suppressing the amount of leakage of the heat transfer gas and workability, three to nine pieces are preferable, and four to eight pieces are more preferable. In addition, the shape of the edge ring pieces may also be such that the edge ring mounting surface 200b1 is divided at unequal intervals in the circumferential direction.

<Edge ring mounting surface 200b1 of electrostatic chuck 200>
Next, the edge ring mounting surface 200b1 of the electrostatic chuck 200 (edge ring adsorption portion 200b) will be described. FIG. 4 is a top view of the electrostatic chuck 200 of the substrate processing apparatus 1 according to this embodiment. The electrostatic chuck 200 has heat transfer gas grooves 231 to 236 on the edge ring mounting surface 200b1 of the electrostatic chuck 200, corresponding to the edge ring pieces 301 to 306, respectively. Specifically, the electrostatic chuck 200 has a heat transfer gas groove 231 in a region where the edge ring piece 301 is adsorbed (a portion facing the back surface of the edge ring piece 301). Similarly, the edge ring adsorption portion 200b has heat transfer gas grooves 232, 233, 234, 235, and 236 in portions facing the back surfaces of the edge ring pieces 302, 303, 304, 305, and 306, respectively. Each of the heat transfer gas grooves 231 to 236 is formed to be recessed in a direction perpendicular to the edge ring mounting surface 200b1. Each of the heat transfer gas grooves 231 to 236 has a heat transfer gas supply hole 231a to 236a. The heat transfer gas supplied from the heat transfer gas supply hole 231a is filled between the edge ring piece 301 and the heat transfer gas groove 231. The same applies to the edge ring pieces 302 to 306 and the heat transfer gas grooves 232 to 236. Since the heat transfer gas grooves 231 to 236 have the heat transfer gas supply holes 231a to 236a, respectively, and are provided separately, the heat transfer gas can be supplied independently to each of the heat transfer gas grooves 231 to 236. The shape of the heat transfer gas grooves is not limited to a sector shape, and the heat transfer gas grooves may be divided in the radial or circumferential direction as long as they are connected to the heat transfer gas supply holes.

<Edge Ring Adsorption Electrode Plate 220 of Electrostatic Chuck 200>
Next, the edge ring attracting electrode plate 220 of the electrostatic chuck 200 will be described. Fig. 5 is a cross-sectional view of the electrostatic chuck 200 of the substrate processing apparatus 1 according to this embodiment. Specifically, it is a cross-sectional view taken along a plane parallel to the edge ring mounting surface 200b1 at the edge ring attracting electrode plate 220 of the electrostatic chuck 200.

The electrostatic chuck 200 includes edge ring adsorption electrode plates 221-226 corresponding to the edge ring pieces 301-306, respectively. Specifically, the electrostatic chuck 200 includes the edge ring adsorption electrode plate 221 inside the area where the edge ring piece 301 is adsorbed (the portion facing the back surface of the edge ring piece 301). Similarly, the electrostatic chuck 200 includes edge ring adsorption electrode plates 222, 223, 224, 225, 226 inside the portions facing the back surfaces of the edge ring pieces 302, 303, 304, 305, 306, respectively. Each of the edge ring adsorption electrode plates 221-226 has a power supply portion 221a-226a that is powered by the DC power source 28. In addition, each of the edge ring adsorption electrode plates 221-226 has a through hole 221b-226b through which the gas supply line 46 passes. The edge ring adsorption electrode plates 221-226 each have a power supply section 221a-226a and are provided separately, so that a voltage can be supplied (applied) independently to each of the edge ring adsorption electrode plates 221-226.

The amount of heat transfer gas leakage can be controlled by controlling the voltage applied to the edge ring adsorption electrode plates 221-226. By controlling the applied voltage and thus controlling (reducing) the amount of leakage, the temperature of the edge ring pieces 301-306 can be stabilized.

<Supply of Heat Transfer Gas to Electrostatic Chuck 200>
Next, an example of a method for controlling the mounting table assembly 5 will be described. Here, the supply of heat transfer gas to the electrostatic chuck 200 will be described. FIG. 6 is a diagram for explaining the supply of heat transfer gas to the electrostatic chuck 200 of the substrate processing apparatus 1 according to this embodiment. The heat transfer gas supply holes 231a to 236a of the heat transfer gas grooves 231 to 236 provided corresponding to the edge ring pieces 301 to 306 are connected to a second heat transfer gas supply unit 45. The second heat transfer gas supply unit 45 includes pressure control valves 45b1 to 45b6 corresponding to the heat transfer gas grooves 231 to 236. The pressure of each of the pressure control valves 45b1 to 45b6 can be set by the control unit 43. Each of the pressure control valves 45b1 to 45b6 controls the pressure of the heat transfer gas to be supplied to a set pressure value. The mounting table assembly 5 is controlled by controlling the heat transfer gas to the electrostatic chuck 200.

The control unit 43 may set the pressure setting value of each pressure control valve 45b1-45b6 to the same value. In addition, the control unit 43 may change the pressure setting value of each pressure control valve 45b1-45b6 based on the substrate processing results of the substrate processing apparatus 1. For example, the pressure setting value of the pressure control valve corresponding to the edge ring piece close to the area with a fast processing rate may be changed (e.g., increased) so as to slow down the processing rate. Furthermore, the control unit 43 may change the pressure setting value of each pressure control valve 45b1-45b6 based on the temperature of each edge ring piece 301-306. For example, the pressure setting value of the pressure control valve corresponding to the edge ring piece with a high temperature may be changed (e.g., increased).

Here, we will explain a control method for changing the pressure setting value of each pressure control valve 45b1-45b6 based on the temperature of each edge ring piece 301-306. Figure 7 is a diagram for explaining the pressure control of the heat transfer gas to the electrostatic chuck 200 of the substrate processing apparatus 1 according to this embodiment. Specifically, it is a flowchart of the control performed by the control unit 43. Each processing step (process) will be explained.

(Step S10)
First, the control unit 43 acquires correlation information (data showing the correlation) between the temperature of the edge ring piece (edge ring temperature) and the pressure set value of the pressure control valve from the memory. The memory stores correlation information (data showing the correlation) between the edge ring temperature measured in advance and the pressure set value of the pressure control valve. FIG. 8 is a diagram for explaining the correlation between the edge ring temperature and the pressure set value of the pressure control valve of the substrate processing apparatus 1 according to the present embodiment. FIG. 8(a) is a diagram showing the relationship between the edge ring temperature (T) measured in step S30 described later and the pressure set value (P) of the heat transfer gas to be controlled by the pressure control valve. On the other hand, FIG. 8(b) is a diagram showing the edge ring temperature (T') when the heat input from the plasma is assumed to be constant and the pressure set value (P) of the heat transfer gas is controlled according to FIG. 8(a). The memory is an example of a storage unit.

The location for storing the correlation information (data showing the correlation) between the edge ring temperature and the pressure setting value of the pressure control valve is not limited to a memory, but can be anything that can store information, such as a disk device.

(Step S20)
Next, the control unit 43 performs control so as to supply the heat transfer gas to the heat transfer gas groove to perform substrate processing.

(Step S30)
Next, the control unit 43 performs control so as to measure the temperature of the edge ring piece corresponding to the pressure control valve. For example, the control unit 43 performs control so as to measure the temperature of the edge ring piece 301 corresponding to the pressure control valve 45b1. The temperature of the edge ring piece may be measured optically, or may be measured by providing a temperature sensor that measures the temperature of the edge ring piece and bringing the temperature sensor into contact with the edge ring piece.

(Step S40)
Next, the control unit 43 determines a pressure setting value of the pressure control valve from the temperature of the edge ring piece whose temperature was measured in step S30, for example, the temperature of the edge ring piece 301, and the correlation information (data indicating the correlation) acquired in step S10. Then, the control unit 43 controls the pressure of the pressure control valve corresponding to the edge ring whose temperature was measured in step S30, for example, the pressure control valve 45b1 corresponding to the edge ring piece 301, to the pressure setting value determined above.

For example, if the temperature of the edge ring piece 301 measured in step S30 is T1, the pressure control valve 45b1 is controlled based on FIG. 8(a) to adjust the pressure setting value to P1. As a result, assuming that the heat input from the plasma is constant, it can be seen from FIG. 8(b) that the temperature of the edge ring piece 301 will eventually become T1'.

(Step S50)
Next, the control unit 43 judges whether all the pressure control valves have been controlled. If there is any pressure control valve that is not being controlled (if "No" in step S50), the process returns to step S20 and is repeated. For example, if the control of the pressure control valve 45b1 is finished and the control of the pressure control valve 45b2 is not being performed, the process returns to step S20 and the pressure control valve 45b2 is controlled. The same applies to the other pressure control valves. If all the pressure control valves have been controlled (if "Yes" in step S50), the process proceeds to step S60.

(Step S60)
Next, the control unit 43 judges whether the substrate processing is completed. If the substrate processing is completed (Yes in step S60), the processing is terminated. If the processing is not completed (No in step S60), the processing returns to step S30 and is repeated. Between step S20 and step S60, the process of processing the substrate is performed in parallel.

By performing the above processing, the pressure set value of the pressure control valve, i.e., the pressure supplied to each heat transfer gas groove, is changed based on the temperature of the corresponding edge ring piece by referring to a memory unit that stores correlation information (data showing the correlation) between the temperature of the edge ring piece and the pressure set value. Note that a substrate processing method including this control method is an example of a substrate processing method using the substrate processing apparatus 1.

In step S30, the temperature of the edge ring piece was measured, but the temperature may be estimated from the substrate processing results, and the estimated result may be used as the temperature of the edge ring piece. Also, the temperature during etching may be fed back and controlled.

Figure 9 is a diagram illustrating an example of the distribution of the etching rate in the substrate processing apparatus 1 according to this embodiment. For example, in Figure 9, region RA of the substrate W (wafer) indicates the region where it is desired to increase the etching rate. Also, in Figure 9, region RB of the substrate W (wafer) indicates the portion where it is desired to decrease the etching rate.

First, the region RA of the substrate W (wafer) will be described. If it is desired to increase the etching rate of the region RA of the substrate W (wafer), the pressure of the heat transfer gas of the edge ring piece 306 adjacent to the region RA is increased. FIG. 10 is a diagram for explaining the relationship between the pressure of the heat transfer gas on the back surface of the wafer and the temperature of the wafer. Increasing the pressure of the heat transfer gas on the back surface of the wafer decreases the temperature of the wafer. Similarly, for the edge ring piece 306, increasing the pressure of the heat transfer gas of the edge ring piece 306 decreases the temperature of the edge ring piece 306. By lowering the temperature of the edge ring piece 306, the etching rate in the region RA of the substrate W (wafer) near the edge ring piece 306 can be increased. Note that the above description is an example, and depending on the film type (film material) of the substrate W, lowering the temperature of the etching ring piece may decrease the etching rate. In this case, the etching rate can be increased by increasing the temperature of the edge ring piece.

Next, the region RB of the substrate W (wafer) will be described. If it is desired to lower the etching rate of the region RB of the substrate W (wafer), the pressure of the heat transfer gas of the edge ring piece 303 adjacent to the region RB is lowered. As with FIG. 10, when the pressure of the heat transfer gas of the edge ring piece 303 is lowered, the temperature of the edge ring piece 303 also increases. By raising the temperature of the edge ring piece 303, the etching rate in the region RB of the substrate W (wafer) adjacent to the edge ring piece 303 can be lowered. Note that the above description is an example, and depending on the film type of the substrate W, raising the temperature of the etching ring piece may increase the etching rate. In this case, the etching rate can be lowered by lowering the temperature of the edge ring piece.

In this way, the edge ring 300 is composed of multiple edge ring pieces 301-306 divided in the circumferential direction, and the temperature controllability of the edge ring can be improved by independently controlling the pressure of each edge ring piece 301-306. In other words, the temperature can be controlled for each area corresponding to the divided edge ring pieces 301-306.

Furthermore, a substrate processing method using the substrate processing apparatus 1 will be described. FIG. 11 is a diagram for explaining the substrate processing method of the substrate processing apparatus 1 according to this embodiment. Specifically, it is a flowchart of the control performed by the control unit 43. Each processing step (process) will be described.

(Step S110)
First, the control unit 43 performs control so that the edge ring pieces 301, 302, 303, 304, 305, and 306 are attracted to the edge ring attracting portion 200b.

(Step S120)
Next, the control unit 43 performs control so as to supply the heat transfer gas to the heat transfer gas groove to perform substrate processing.

(Step S130)
Next, the control unit 43 starts processing (substrate processing) of the substrate W (wafer). As the substrate processing, for example, etching of the substrate W (wafer) is performed.

(Step S140)
Next, the control unit 43 controls the pressure of the heat transfer gas for each region, i.e., for each edge ring piece.

(Step S150)
Next, the control unit 43 judges whether the substrate processing is completed. If the substrate processing is completed (Yes in step S150), the processing is terminated. If the processing is not completed (No in step S150), the processing returns to step S140 and is repeated. Between step S130 and step S150, a process of processing the substrate is performed in parallel.

By performing the above process, the temperature of each edge ring piece can be controlled.

<Supply of Power to Electrostatic Chuck 200>
Next, an example of a method for controlling the mounting table assembly 5 will be described. Here, the supply of power to the electrostatic chuck 200 will be described. FIG. 12 is a diagram for explaining the supply of power to the electrostatic chuck 200 of the substrate processing apparatus 1 according to this embodiment. The edge ring adsorption electrode plates 221 to 226 provided corresponding to the edge ring pieces 301 to 306 are connected to a DC power source 28. The DC power source 28 includes voltage conversion units 28b1 to 28b6 corresponding to the edge ring adsorption electrode plates 221 to 226. The voltage conversion units 28b1 to 28b6 can set the voltages to be output by the control unit 43. The voltage conversion units 28b1 to 28b6 perform control so that the voltages to be output are set to the set voltage values. The mounting table assembly 5 is controlled by controlling the power to the electrostatic chuck 200.

Furthermore, a substrate processing method using the substrate processing apparatus 1 will be described. FIG. 13 is a diagram for explaining the substrate processing method of the substrate processing apparatus 1 according to this embodiment. Specifically, it is a flowchart of the control performed by the control unit 43. Each processing step (process) will be described.

(Step S210)
First, the control unit 43 performs control so that the edge ring pieces 301, 302, 303, 304, 305, and 306 are attracted to the edge ring attracting portion 200b.

(Step S220)
Next, the control unit 43 performs control so as to supply the heat transfer gas to the heat transfer gas groove to perform substrate processing.

(Step S230)
Next, the control unit 43 starts processing (substrate processing) of the substrate W (wafer). As the substrate processing, for example, etching of the substrate W (wafer) is performed.

(Step S240)
Next, the control unit 43 controls the voltage applied to the electrodes for each region, i.e., for each electrode of the edge ring piece.

(Step S250)
Next, the control unit 43 judges whether the substrate processing is completed. If the substrate processing is completed (Yes in step S250), the processing is terminated. If the processing is not completed (No in step S250), the processing returns to step S140 and is repeated. Between step S230 and step S250, a process of processing the substrate is performed in parallel.

By performing the above process, the temperature of each edge ring piece can be controlled.

For example, the process will be described with reference to FIG. 9. The area RA of the substrate W (wafer) will be described. If it is desired to increase the etching rate of the area RA of the substrate W (wafer), the voltage supplied to the edge ring adsorption electrode plate 226 corresponding to the edge ring piece 306 adjacent to the area RA is increased. Increasing the voltage supplied to the edge ring adsorption electrode plate 226 corresponding to the edge ring piece 306 reduces the temperature of the edge ring piece 306. By lowering the temperature of the edge ring piece 306, the etching rate in the area RA of the substrate W (wafer) near the edge ring piece 306 can be increased. Note that the above description is an example, and depending on the film type of the substrate W, lowering the temperature of the etching ring piece may reduce the etching rate. In this case, the etching rate can be increased by raising the temperature of the edge ring piece.

Next, the region RB of the substrate W (wafer) will be described. If it is desired to lower the etching rate of the region RB of the substrate W (wafer), the voltage supplied to the edge ring adsorption electrode plate 223 corresponding to the edge ring piece 303 adjacent to the region RB is lowered. If the voltage supplied to the edge ring adsorption electrode plate 223 corresponding to the edge ring piece 306 is lowered, the temperature of the edge ring piece 303 increases. By raising the temperature of the edge ring piece 303, the etching rate in the region RB of the substrate W (wafer) near the edge ring piece 303 can be lowered. Note that the above description is an example, and depending on the film type of the substrate W, raising the temperature of the etching piece may increase the etching rate. In this case, the etching rate can be lowered by lowering the temperature of the edge ring piece.

In this way, the edge ring 300 is composed of multiple edge ring pieces 301-306 divided in the circumferential direction, and the voltage that attracts each edge ring piece 301-306 can be controlled independently, thereby improving the temperature controllability of the edge ring. In other words, the temperature can be controlled for each area corresponding to the multiple divided edge ring pieces 301-306.

<Setting the heat transfer gas pressure and power supply voltage>
The pressure of the heat transfer gas and the set value of the voltage of the power supply may be determined, for example, by the number of substrates or the number of lots processed in the substrate processing apparatus 1. For example, FIG. 14 is a diagram for explaining the variation rate of the etching rate and the number of substrates processed in the substrate processing apparatus 1 according to this embodiment. The horizontal axis indicates the radial position of the wafer to be processed. The vertical axis indicates the variation rate of the etching rate. Line N1 indicates the variation rate of the etching rate when one wafer is processed (first wafer). Line N10 indicates the variation rate of the etching rate when ten wafers are processed (tenth wafer). Line N25 indicates the variation rate of the etching rate when 25 wafers are processed (25th wafer).

When the number of wafers that have undergone substrate processing increases, the etching rate of the wafer, especially the edge, decreases. The reason why the etching rate of the wafer decreases when the number of wafers that have undergone substrate processing increases is because the temperature of the edge ring rises when the substrate processing is performed. Note that FIG. 14 shows the results of a test of the fluctuation when the edge ring is not adsorbed and cooling gas is not introduced. Therefore, the settings of the pressure of the heat transfer gas and the voltage of the power supply may be changed based on data showing the correlation between the etching rate and the number of wafers that have undergone substrate processing (number of wafers processed). In addition, since the number of wafers that have undergone substrate processing (number of wafers processed) can be considered to be the time during which the substrate is processed, that is, the processing time of the substrate, the etching rate and the processing time of the substrate may be set based on data showing the correlation between the processing time of the substrate. Furthermore, the setting of the voltage of the power supply may be changed based on correlation information (data showing the correlation) between the temperature of the edge ring piece and the voltage setting value.

The temperature of the edge ring piece may be controlled by combining control of the pressure of the heat transfer gas supplied to the edge ring piece and control of the voltage supplied to the electrode.

<End Structure of Edge Ring Pieces 301 to 306>
The structure of the divided portion of the edge ring 300, that is, the end structure of the edge ring pieces 301 to 306 will be described. The end structure of the edge ring pieces 301 to 306 is preferably a structure in which the edge ring mounting surface 200b1 is not exposed to plasma between adjacent edge ring pieces, for example, at the joint between the end 301b of the edge ring piece 301 and the end 302a of the edge ring piece 302 in FIG. 3 and the joint between the end 301a of the edge ring piece 301 and the end 306b of the edge ring piece 306. Specifically, each of the edge ring pieces 301 to 306 preferably has a complementary structure in which the ends of the adjacent edge ring pieces 301 to 306 overlap in the vertical direction at both ends in the circumferential direction. The end structures of the edge ring piece 301 and the edge ring pieces 302 and 306 adjacent to this edge ring piece 301 will be described below. Note that in the following description, a specific edge ring piece will be described, but the same applies to other edge ring pieces.

[First Example]
FIG. 15 is a cross-sectional view of an edge ring piece 301A of the substrate processing apparatus 1 according to this embodiment, and end portions of edge ring pieces 302A and 306A adjacent to the edge ring piece 301A.

In FIG. 15, the left end of edge ring pieces 301A, 302A, and 306A is one end, and the right end is the other end. Edge ring pieces 301A and 302A have first inclined surfaces 301Aa and 302Aa, respectively, at one end. Edge ring pieces 301A and 306A have second inclined surfaces 301Ab and 306Ab, respectively, at the other end. Here, when edge ring 300 is attached to edge ring suction portion 200b, first inclined surface 301Aa of edge ring piece 301A abuts against second inclined surface 306Ab of adjacent edge ring piece 306A. Similarly, second inclined surface 301Ab of edge ring piece 301A abuts against first inclined surface 302Aa of adjacent edge ring piece 302A. That is, the first inclined surface 301Aa of the edge ring piece 301A is a complementary inclined surface that overlaps vertically with the second inclined surface 306Ab of the adjacent edge ring piece 306A. Also, the second inclined surface 301Ab of the edge ring piece 301A is a complementary inclined surface that overlaps vertically with the first inclined surface 302Aa of the adjacent edge ring piece 302A. Therefore, according to the first example, it is possible to avoid exposure of the edge ring mounting surface 200b1 to plasma at the joint between the edge ring piece 301A and the edge ring pieces 302A and 306A adjacent to this edge ring piece 301A.

[Second Example]
FIG. 16 is a cross-sectional view of an edge ring piece 301B of the substrate processing apparatus 1 according to this embodiment and end portions of edge ring pieces 302B and 306B adjacent to this edge ring piece 301B.

In FIG. 16, the left end of edge ring pieces 301B, 302B, and 306B is one end, and the right end is the other end. Edge ring pieces 301B and 302B have first step portions 301Ba and 302Ba at one end, respectively. Edge ring pieces 301B and 306B have second step portions 301Bb and 306Bb at the other end, respectively. Here, when edge ring 300 is attached to edge ring suction portion 200b, first step portion 301Ba of edge ring piece 301B fits into second step portion 306Bb of adjacent edge ring piece 306B. Similarly, second step portion 301Bb of edge ring piece 301B fits into first step portion 302Ba of adjacent edge ring piece 302B. That is, the first step portion 301Ba of the edge ring piece 301B is a complementary step portion that overlaps vertically with the second step portion 306Bb of the adjacent edge ring piece 306B. Also, the second step portion 301Bb of the edge ring piece 301B is a complementary step portion that overlaps vertically with the first step portion 302Ba of the adjacent edge ring piece 302B. Therefore, according to the second example, it is possible to avoid exposure of the edge ring mounting surface 200b1 to plasma at the joints between the edge ring piece 301B and the edge ring pieces 302B and 306B adjacent to this edge ring piece 302B.

[Third Example]
FIG. 17 is a cross-sectional view of an edge ring piece 301C of the substrate processing apparatus 1 according to this embodiment and end portions of edge ring pieces 302C and 306C adjacent to this edge ring piece 301C.

In FIG. 17, the left end of edge ring pieces 301C, 302C, and 306C is one end, and the right end is the other end. Edge ring pieces 301C and 302C each have a convex portion 301Ca, 302Ca at one end. Edge ring pieces 301C and 306C each have a concave portion 301Cb, 306Cb at the other end. Here, when edge ring 300 is attached to edge ring suction portion 200b, convex portion 301Ca of edge ring piece 301C fits into concave portion 306Cb of adjacent edge ring piece 306C. Similarly, concave portion 301Cb of edge ring piece 301C fits into convex portion 302Ca of adjacent edge ring piece 302C. That is, the convex portion 302Ca of the edge ring piece 301C is a complementary convex portion that overlaps vertically with the concave portion 306Cb of the adjacent edge ring piece 306C. Also, the concave portion 301Cb of the edge ring piece 301C is a complementary concave portion that overlaps vertically with the convex portion 302Ca of the adjacent edge ring piece 302C. Therefore, according to the third example, it is possible to avoid exposure of the edge ring mounting surface 200b1 to plasma at the joints between the edge ring piece 301C and the edge ring pieces 302C and 306C adjacent to this edge ring piece 301C.

The above edge ring end examples may be the same as those used in the mounting table assembly 5 or may be combined.

<Action and Effects>
Conventionally, the edge ring is molded as a single piece, and due to the processing accuracy, there is a certain difference between the flatness of the edge ring mounting surface of the electrostatic chuck and the flatness of the back surface of the edge ring. In addition, since the edge ring is thicker than the substrate W, even if the edge ring is attracted to the electrostatic chuck, it is difficult for the edge ring to deform to match the surface shape of the etching ring mounting surface. In particular, when the flatness of the edge ring mounting surface changes due to a temperature change of the electrostatic chuck during substrate processing, it is difficult for the edge ring to follow the change in the surface shape of the edge ring mounting surface. For this reason, with the edge ring molded as a single piece, it is difficult to suppress the leakage of the heat transfer gas between the edge ring and the electrostatic chuck.

In contrast, according to the mounting table assembly 5 of this embodiment, the edge ring 300 is composed of multiple edge ring pieces 301 to 306. Therefore, even if there is a difference between the flatness of the edge ring mounting surface 200b1 of the electrostatic chuck 200 and the flatness of the back surface of the edge ring 300 (edge ring pieces 301 to 306), the edge ring 300 can be mounted according to the surface shape of the edge ring mounting surface 200b1. Furthermore, even if the flatness of the edge ring mounting surface 200b1 changes due to a temperature change in the electrostatic chuck 200 during substrate processing, the edge ring 300 can follow the change in the surface shape of the edge ring mounting surface 200b1. Therefore, according to the mounting table assembly 5 of this embodiment, leakage of the heat transfer gas can be effectively suppressed. As a result, the pressure of the heat transfer gas can be kept constant during substrate processing, thereby improving the heat transfer efficiency between the edge ring 300 and the electrostatic chuck 200.

Furthermore, the mounting table assembly 5 of this embodiment is provided with heat transfer gas grooves 231-236 for each region in which the multiple edge ring pieces 301-306 are placed. Therefore, the amount of heat transfer gas supplied to each heat transfer gas groove 231-236 can be controlled independently, making it possible to control the temperature of each edge ring piece 301-306.

Furthermore, the mounting table assembly 5 of this embodiment is provided with edge ring adsorption electrode plates 221-226 for each area on which multiple edge ring pieces 301-306 are placed. Therefore, the adsorption force for each edge ring piece 301-306 can be controlled independently, and the temperature distribution for each edge ring piece 301-306 can be controlled.

The substrate processing apparatus according to the present embodiment disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiment can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above-described 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.

The substrate processing apparatus disclosed herein can be applied to any type of apparatus, such as Capacitively Coupled Plasma (CCP), Inductively Coupled Plasma (ICP), microwave plasma generating apparatus, such as plasma generated by a Radial Line Slot Antenna (RLSA), Electron Cyclotron Resonance Plasma (ECR), and Helicon Wave Plasma (HWP).

REFERENCE SIGNS LIST 1 substrate processing apparatus 5 mounting table assembly 100 base 200 electrostatic chuck 200b1 edge ring mounting surface 231 to 236 heat transfer gas groove 300 edge ring 301 to 306, 301A to 301C, 302A to 302C, 306A to 306C edge ring piece W substrate

Claims (16)

A mounting table assembly for mounting a substrate, comprising:
The base and
an electrostatic chuck disposed on the base;
an edge ring disposed around a periphery of the substrate;
Equipped with
the edge ring is composed of a plurality of edge ring pieces divided in a circumferential direction,
the electrostatic chuck has a substrate attracting portion that attracts the substrate and an edge ring attracting portion that attracts the plurality of edge ring pieces,
the edge ring suction portion has a plurality of heat transfer gas grooves provided separately in correspondence with the respective regions to which the plurality of edge ring pieces are suctioned, and into which a heat transfer gas is supplied;
Each of the plurality of heat transfer gas grooves has a heat transfer gas supply hole .
Mounting platform assembly. the edge ring suction portion includes electrodes for suctioning the edge ring pieces in the respective regions,
The stage assembly of claim 1 . 3 . The mounting table assembly according to claim 1 , wherein each of the edge ring pieces has a complementary structure at both circumferential ends thereof that vertically overlaps an end of an adjacent edge ring piece. Each of the plurality of edge ring pieces has a first inclined surface at one end and a second inclined surface at the other end that abuts against the first inclined surface of an adjacent edge ring piece.
The stage assembly of claim 3 . Each of the plurality of edge ring pieces has a first step portion at one end and a second step portion at the other end that fits into the first step portion of an adjacent edge ring piece.
The stage assembly of claim 3 . Each of the plurality of edge ring pieces has a recess at one end and a protrusion at the other end that fits into the recess of an adjacent edge ring piece.
The stage assembly of claim 3 . The edge ring is composed of 3 to 9 edge ring pieces.
The stage assembly of claim 1 . a processing chamber;
a mounting table assembly according to claim 1 , which is disposed within the processing chamber;
A control unit;
The substrate processing apparatus includes: a temperature sensor for measuring a temperature of the edge ring piece;
The substrate processing apparatus according to claim 8 . a processing chamber;
a mounting table assembly for mounting a substrate;
A control unit.
The mounting table assembly includes:
The base and
an electrostatic chuck disposed on the base;
an edge ring disposed around a periphery of the substrate;
Equipped with
the edge ring is composed of a plurality of edge ring pieces divided in a circumferential direction,
the electrostatic chuck has a substrate attracting portion that attracts the substrate and an edge ring attracting portion that attracts the plurality of edge ring pieces,
the edge ring suction portion has a heat transfer gas groove through which a heat transfer gas is supplied in each of the regions to which the edge ring pieces are suctioned;
A substrate processing method using a substrate processing apparatus, comprising:
(a) adsorbing the plurality of edge ring pieces to the edge ring adsorption portion;
(b) supplying a heat transfer gas to the heat transfer gas groove to perform substrate processing;
(c) processing the substrate;
(d) controlling the pressure of the heat transfer gas for each of the regions;
A method for processing a substrate. The step (d) is a step of controlling the pressure of the heat transfer gas for each of the regions based on data showing a correlation between an etching rate and a processing time or a processing number of the substrates.
The method of claim 10 . a temperature sensor for measuring a temperature of each of the edge ring pieces;
The step (d) comprises:
(d-1) measuring the temperatures of the edge ring pieces using the temperature sensor;
(d-2) controlling the pressure of the heat transfer gas for each of the regions based on data indicating a correlation between the temperature of the edge ring piece and the heat transfer gas supplied to the heat transfer gas groove, and based on the measured temperatures of the plurality of edge ring pieces ;
The method of claim 10 . a processing chamber;
a mounting table assembly for mounting a substrate;
A control unit.
The mounting table assembly includes:
The base and
an electrostatic chuck disposed on the base;
an edge ring disposed around a periphery of the substrate;
Equipped with
the edge ring is composed of a plurality of edge ring pieces divided in a circumferential direction,
the electrostatic chuck has a substrate attracting portion that attracts the substrate and an edge ring attracting portion that attracts the plurality of edge ring pieces,
the edge ring suction portion has a heat transfer gas groove through which a heat transfer gas is supplied and an electrode for suctioning the edge ring pieces in each of the regions to which the edge ring pieces are suctioned;
A substrate processing method using a substrate processing apparatus, comprising:
(a) adsorbing the plurality of edge ring pieces to the edge ring adsorption portion;
(b) supplying a heat transfer gas to the heat transfer gas groove;
(c) processing the substrate;
(d) controlling a voltage applied to the electrode for each of the regions;
A method for processing a substrate. The step (d) is a step of controlling a voltage applied to the electrode for each of the regions based on data showing a correlation between an etching rate and a processing time or a processing number of the substrates.
The method of claim 13 . a temperature sensor for measuring a temperature of each of the edge ring pieces;
The step (d) comprises:
(d-1) measuring the temperatures of the edge ring pieces using the temperature sensor;
(d-2) controlling the voltage applied to the electrode for each of the regions based on data indicating a correlation between the temperature of the edge ring piece and the voltage applied to the electrode, and based on the measured temperatures of the plurality of edge ring pieces ;
The method of claim 13 . The step (d) further includes a step of controlling the pressure of the heat transfer gas for each of the regions.
The method of claim 13 .

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