TW201903814A - Substrate processing device - Google Patents

Abstract

A substrate processing apparatus includes a process chamber, a stage that is disposed in the process chamber and on which a substrate is placeable, a moving mechanism, and a focus ring. The focus ring is disposed on the stage and includes an inner focus ring disposed close to the substrate placed on the stage, a middle focus ring that is disposed outside of the inner focus ring and is movable in a vertical direction by the moving mechanism, and an outer focus ring that is disposed outside of the middle focus ring.

Description

Substrate processing device

The present invention relates to a substrate processing apparatus.

In the plasma etching apparatus, a focus ring is provided along the outer periphery of a semiconductor wafer (hereinafter referred to as "wafer") (for example, refer to Patent Document 1). The function of the focus ring is to control the plasma near the outer periphery of the wafer to improve the uniformity of the etching rate in the wafer surface.

The etching rate of the edge portion of the wafer varies with the height of the focus ring. Therefore, if the height is changed due to the loss of the focus ring, the etching rate of the edge portion of the wafer is higher than that of the center or middle portion of the wafer, etc., and it becomes difficult to control the etching of the edge portion of the wafer. characteristic. In view of this, in Patent Document 1, a driving unit that drives the focus ring up and down is provided to control the position of the top surface of the focus ring and improve the controllability of the edge portion of the wafer. [Habitual technical literature] [patent literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2008-244274

[Problems to be solved by the invention]

However, in Patent Document 1, the inner focus ring of the two divided focus rings is kept fixed, and only the outer focus ring is moved up and down. In this mechanism, if the outer focus ring is moved up and down, the etching rate of the entire wafer will be shifted. Therefore, the etching characteristics of the entire wafer change, and it is difficult to control only the etching characteristics of the edge portion of the wafer.

In view of the above problems, on one level, the object of the present invention is to maintain the processing characteristics for the entire surface of the substrate and control the processing characteristics for the edge portion of the substrate. [Technical means to solve the problem]

In order to solve the above-mentioned problem, one aspect of the present invention provides a substrate processing apparatus having a focusing ring. The focusing ring includes an inner focusing ring disposed near a substrate, and the substrate is a workpiece table placed in a processing chamber. A central focusing ring is provided. Is provided outside the inner focus ring and can be moved up and down by a moving mechanism; and an outer focus ring is provided outside the central focus ring. [Effect of the invention]

With one aspect of the present invention, it is possible to maintain the processing characteristics for the entire surface of the substrate on the one hand and control the processing characteristics for the edge portion of the substrate.

Hereinafter, the form for implementing this invention is demonstrated with reference to drawings. In this specification and the drawings, the same reference numerals are given to substantially the same configurations, and redundant descriptions are omitted.

[Substrate Processing Apparatus] First, an example of a configuration of a substrate processing apparatus 5 according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 shows an example of the structure of a substrate processing apparatus 5 according to this embodiment. In the present embodiment, a parallel-plate plasma processing apparatus of a capacitive coupling type will be described as an example of the substrate processing apparatus 5.

The substrate processing apparatus 5 includes a processing chamber 10 which is, for example, a cylindrical vacuum container made of metal such as aluminum or stainless steel. The processing chamber 10 is an example of a processing container, and the inside thereof is a processing chamber for performing plasma processing. The processing chamber 10 is grounded.

A disc-shaped workpiece stage 12 is disposed in the center of the lower portion in the processing chamber 10. The workpiece stage 12 also serves as a substrate holding stage for the lower electrode, and, for example, a wafer W to be processed is placed. The work table 12 is made of, for example, aluminum, and is supported by a conductive cylindrical support portion 16 extending vertically upward from the bottom of the processing chamber 10 and a housing 100 provided adjacent to the inside.

An annular exhaust path 18 is formed between the conductive cylindrical support portion 16 and the inner wall of the processing chamber 10. An annular baffle 20 is installed at the upper part or the inlet of the exhaust path 18, and an exhaust port 22 is provided at the bottom. In order to make the air flow in the processing chamber 10 axially symmetrical with respect to the wafer W on the work table 12, it is preferable that the exhaust ports 22 be configured so that a plurality of exhaust ports 22 are provided at regular intervals in the circumferential direction.

Each exhaust port 22 is connected to an exhaust device 26 via an exhaust pipe 24. The exhaust device 26, a vacuum pump having a turbo molecular pump, or the like, can reduce the plasma generation space S in the processing chamber 10 to a desired vacuum degree. A gate valve 28 is installed outside the side wall of the processing chamber 10 to open and close the carry-in outlet 27 of the wafer W.

The work table 12 is electrically connected to the second high-frequency power source 30 via the matching device 32 and the power supply rod 34. The second high-frequency power source 30 is capable of outputting a high-frequency LF of a first frequency (for example, 13.56 MHz) with variable power, and is suitable for controlling the energy of introducing ions into the wafer W. The matcher 32 contains a variable reactance matching circuit for matching the impedance on the second high-frequency power source 30 side with the impedance on the load (plasma, etc.) side.

An electrostatic chuck 36 is provided on the top surface of the workpiece table 12 to hold the wafer W by an electrostatic attraction force. The electrostatic chuck 36 is connected between a pair of insulating films 36b, and an electrode 36a made of a conductive film is inserted. The electrode 36a is electrically connected to the DC power source 40 through a switch 42 and a covered wire 43. The wafer W is sucked and held on the electrostatic chuck 36 by an electrostatic force by a DC current supplied from the DC power source 40.

Inside the work table 12, for example, a ring-shaped refrigerant flow path 44 extending in the circumferential direction is provided. A cooling medium, such as cooling water cw, is circulated and supplied to the cooling medium flow path 44 from the cooling unit through pipes 46 and 48; the temperature of the wafer W on the electrostatic chuck 36 can be controlled by the temperature of the cooling medium. In addition, a heat radiation gas, such as helium gas, from the heat radiation gas supply portion is supplied between the top surface of the electrostatic chuck 36 and the back surface of the wafer W through the gas supply pipe 50. Furthermore, in order to carry in and out of the wafer W, an ejector pin that penetrates the work table 12 in the vertical direction and can be moved up and down, and an elevating mechanism thereof are provided.

The air-jet head 51 provided in the ceiling opening of the processing chamber 10 is installed to block the ceiling opening of the processing chamber 10 via a seal ring 54 covering the outer edge portion thereof. The jet head 51 is formed of silicon. The air jet head 51 also has a function of an opposite electrode (upper electrode) facing the workpiece table 12 (lower electrode).

The gas injection head 51 is formed with a gas introduction port 56 through which gas is introduced. A diffusion chamber 58 branched from the gas introduction port 56 is provided inside the air-jet head 51. The gas output from the gas supply source 66 is supplied to the diffusion chamber 58 through the gas introduction port 56, diffuses, and is introduced into the plasma generation space S from a plurality of gas supply holes 52.

The air jet head 51 is electrically connected to the first high-frequency power source 57 via the matching device 59 and the power supply line 60. The first high-frequency power supply 57 can generate a high-frequency HF for a plasma with a variable power output. The first high-frequency power supply 57 is suitable for generating a plasma with a high-frequency discharge. 40MHz). The matching device 59 stores a variable reactance matching circuit for matching the impedance on the side of the first high-frequency power supply 57 and the impedance on the load (plasma, etc.) side.

The control unit 74 includes, for example, a microcomputer, and controls operations of each section in the substrate processing apparatus 5 and operations of the entire apparatus. The various sections in the substrate processing apparatus 5 include an exhaust device 26, a first high-frequency power supply 57, a second high-frequency power supply 30, a matching device 32, a matching device 59, a switch 42 for an electrostatic chuck, A gas supply source 66, a cooling unit, a heat radiation gas supply unit, and the like.

When the substrate processing apparatus 5 performs various processes such as etching, the gate valve 28 is first opened, and the wafer W is carried into the processing chamber 10 and placed on the electrostatic chuck 36. Then, after closing the gate valve 28, a predetermined gas is introduced into the processing chamber 10 from the gas supply source 66 at a predetermined flow rate and flow ratio, and the pressure in the processing chamber 10 is reduced to a predetermined setting by the exhaust device 26 value. Furthermore, the first high-frequency power supply 57 is turned on, and a high-frequency HF for plasma is generated at a predetermined power output, and then supplied to the air jet head 51 through the matching device 59 and the power supply line 60.

On the other hand, when a high-frequency LF for controlling ion introduction is applied, the second high-frequency power source 30 is turned on, and a high-frequency LF is output at a predetermined power, and then passed through the matcher 32 and the power supply rod 34. Applied to the work table 12. Furthermore, the heat-dissipating gas is supplied from the heat-dissipating gas supply portion to the contact surface between the electrostatic chuck 36 and the wafer W, and at the same time, the switch 42 is turned on, and a DC voltage from the DC power source 40 is applied to the electrode 36a of the electrostatic chuck 36. Then, the heat-dissipating gas is locked into the above-mentioned contact surface by the electrostatic adsorption force.

[Focus Ring Divided into Three Parts] A focus ring FR is provided on the outer peripheral side of the work table 12 to surround the outer edge of the wafer W in a ring shape. The function of the focus ring FR is to control the plasma on the outer peripheral side of the wafer W to improve the uniformity of processing such as the in-plane etching rate of the wafer W.

The etching rate of the edge portion of the wafer W varies with the height of the focus ring FR. Therefore, if the height of the focus ring FR is changed, the etching rate of the edge portion of the wafer W will change, and it will be difficult to control the edge portion.

In view of this, the focus ring FR of this embodiment is divided into three parts, and has an inner focus ring 38i, a central focus ring 38m, and an outer focus ring 38o, and the central focus ring 38m can be moved up and down by the moving mechanism 200. The moving mechanism 200 includes an ejector pin 102. The ejector pin 102 is moved up and down by the power generated by the piezoelectric actuator 101 via the member 104a and the bearing portion 105. As a result, the connecting portion 103 moves up and down, and the central focus ring 38m connected to the connecting portion 103 also moves up and down. In addition, in this embodiment, the edge portion of the wafer W means an annular portion of 140 mm to 150 mm in the radial direction from the center of the wafer W.

(Structure of Focus Ring) Next, the structure of the focus ring FR and its surroundings will be described in detail with reference to FIGS. 2 and 3. The up-and-down movement of the center focus ring 38m will be described with reference to FIG. 4.

FIG. 2 is an enlarged view showing an example of a longitudinal section of the focus ring FR and its periphery. FIG. 2 illustrates a focus ring FR, a moving mechanism 200 and a piezoelectric actuator 101 in this embodiment.

Fig. 3 (a) is a perspective view of each part of the focus ring FR divided into three parts, Fig. 3 (b) is a top view of each part of the focus ring FR divided into three parts, and Fig. 3 (c) is an AA section of Fig. 3 (b) 3 (d) is a cross-sectional view taken along the line BB of FIG. 3 (b).

As shown in FIGS. 2 and 3, the inner focus ring 38 i is a member that surrounds the wafer W from below and is the innermost member of the focus ring FR near the outermost periphery of the wafer W. The central focus ring 38m is a member provided to surround the inner focus ring 38i outside the inner focus ring 38i. The outer focus ring 38o is a member provided outside the center focus ring 38m, and is the outermost member of the focus ring FR. The inner focus ring 38i and the outer focus ring 38o are fixed to the top surface of the electrostatic chuck 36. The central focus ring 38m can be moved up and down by the moving mechanism 200.

The center focus ring 38m has, as shown in FIGS. 3 (a) and 3 (b), an annular portion 38m1 surrounding the peripheral edge portion of the wafer W, and three claw portions 38m2. The claw portions 38 m 2 are arranged at regular intervals on the outer peripheral side of the ring portion 38 m 1 and are rectangular members protruding from the outer peripheral side of the ring portion 38 m 1. As shown in FIG. 2, the longitudinal section of the annular portion 38 m 1 is L-shaped. When the center focus ring 38m is lifted upward, the L-shaped step portion of the ring portion 38m1 will be separated from the state in which it contacts the step portion of the inner focus ring 38i having an L-shaped longitudinal section.

(Movement mechanism and drive unit) The claw portion 38m2 of the center focus ring 38m is connected to the ring-shaped connecting portion 103. The connecting portion 103 moves up and down inside the space 16 a provided in the conductive cylindrical support portion 16.

The moving mechanism 200 is a mechanism for moving the central focus ring 38m up and down. The moving mechanism 200 includes an ejector pin 102 and a bearing portion 105. The moving mechanism 200 is mounted on the casing 100 arranged around the work table 12 and moves up and down by the power of the piezoelectric actuator 101 mounted on the casing 100. The ejector pin 102 may also be formed of sapphire.

The case 100 is formed of an insulator such as alumina. The casing 100 is inside the conductive cylindrical support portion 16, and the side portion and the bottom portion are provided adjacent to the conductive cylindrical support portion 16. A recessed portion 100 a is formed on the lower side of the inside of the case 100. A moving mechanism 200 is provided inside the casing 100. The ejector pin 102 penetrates the housing 100 and the work table 12 and is in contact with the bottom surface of the connecting portion 103 in the space 16 a of the conductive cylindrical support portion 16. The bearing portion 105 is fitted to a member 104 a provided inside the housing 100. The pin hole of the ejector pin 102 is provided with an O-ring 111 for dividing the vacuum space and the atmospheric space.

The lower end of the ejector pin 102 is fitted into the recessed portion 105 a at the front end of the bearing portion 105. By the positioning performed by the piezoelectric actuator 101 and the bearing portion 105 is moved up and down through the member 104a, the ejector pin 102 is moved up and down, and the bottom surface of the connecting portion 103 is pushed up or down. Thereby, 38 m of center focus rings are moved up and down via the connection part 103.

The upper end of the piezoelectric actuator 101 is locked to the member 104a with a screw 104c; the lower end of the piezoelectric actuator 101 is locked to the member 104b with a screw 104d. Thereby, the piezoelectric actuator 101 is fixed between the members 104 a and 104 b and fixed to the case 100.

The piezoelectric actuator 101 is a positioning element using a piezoelectric effect, and can perform positioning at a resolution of 0.006 mm (6 μm). The ejector pin 102 moves up and down in accordance with the amount of displacement of the piezoelectric actuator 101 in the vertical direction. As a result, the central focus ring of 38m will move by 0.006mm as the minimum unit and only move a predetermined height.

The ejector pins 102 are provided corresponding to the claw portions 38m2 provided at three positions in the circumferential direction of the central focus ring 38m at equal intervals as shown in Figs. 3 (a) and 3 (b). With this structure, the ejector pin 102 will lift the central focus ring 38m from three places through the ring-shaped connecting portion 103 to be raised to a predetermined height.

A concave portion 138 is formed on the bottom surface of the outer focus ring 38o above the claw portion 38m2 of the central focus ring 38m to be wider than the claw portion 38m2. Once the center focus ring 38m is moved to the uppermost position by the pushing up of the ejector pin 102, the claw portion 38m2 will be retracted into the inside of the recessed portion 138. Thereby, the outer focus ring 38o can be kept fixed, and the central focus ring 38m is pushed upward.

In FIG. 3 (d), which shows the BB section of FIG. 3 (b), the space where the recess 138 does not exist and the ejector pin 102 are shown. By moving the ejector pin 102 upward, the ring shape is formed. The connection portion 103 is pushed up in the space 16 a of the conductive cylindrical support portion 16.

Returning to FIG. 2; the piezoelectric actuator 101 is located in the inner space of the housing 100 below the ejector pin 102 and is disposed one-to-one with the ejector pin 102. In other words, three moving mechanisms 200 and piezoelectric actuators 101 are provided one-to-one correspondingly to the ejector pins 102 existing at three locations inside the housing 100. The members 104a, 104b are ring members, and the three piezoelectric actuators 101 are connected to each other by the members 104a, 104b which are locked up and down. The piezoelectric actuator 101 according to this embodiment is an example of a driving unit.

As described above, in this structure, the work table 12 and the electrostatic chuck 36 are supported by the casing 100, and the moving mechanism 200 and the driving unit are mounted on the casing 100. Thereby, it is not necessary to change the design of the electrostatic chuck 36, and only the central focus ring 38m can be moved up and down using the existing electrostatic chuck 36. Furthermore, as shown in FIG. 2, in the structure of this embodiment, a predetermined space is provided between the top surface of the electrostatic chuck 36 and the bottom surface of the central focusing ring 38m, so that the central focusing ring 38m can not only move upward, You can also move down. With this, the central focusing ring 38m can not only move upward, but also move a predetermined height downward in a predetermined space. By making the central focusing ring 38m not only move upwards, but also downwards, the control range of the sheath can be enlarged.

However, the driving section is not limited to the piezoelectric actuator 101, and a motor capable of positioning control at a resolution of 0.006 mm may be used. In addition, the driving unit may be one or plural. Furthermore, the driving unit may share a motor that moves the "ejector pin for pushing up the wafer W" up and down. In this case, a mechanism capable of switching the power of the motor between the ejector pin for the wafer W and the ejector pin 102 for the center focus ring 38m using a gear and a power switching unit, and The resolution of 0.006mm controls the mechanism of the ejector pin 102 moving up and down. However, since the diameter of the central focusing ring 38m disposed on the outer periphery of the 300mm wafer W is about 310mm, which is relatively large, it is preferable to provide a driving section for each ejector pin 102 as in this embodiment.

The control section 74 controls the positioning of the piezoelectric actuator 101 so that the displacement amount of the piezoelectric actuator 101 in the up-down direction will be a weight corresponding to the loss of 38 m of the central focus ring.

If the height of the wafer W and the top surface of the focus ring FR is the same, the height of the sheath on the wafer W in the etching process and the height of the sheath on the focus ring FR can be made the same. Then, by making the heights of the sheaths the same, the uniformity of the etching rate in the entire surface of the wafer W can be improved.

If the focusing ring FR is a new product, since the sheath on the wafer W and the sheath on the focusing ring FR are the same height (flat) during the etching process, the entire etching rate on the surface of the wafer W will be uniform. . At this time, as shown in FIG. 4 (a-1), the center focus ring 38m is not pushed up (0mm) by the ejector pin 102. 4 (a-1) illustrates a state of the A-A section of FIG. 3 (b), and FIG. 4 (b-1) illustrates a state of a corresponding B-B section of FIG. 3 (b).

However, if the focus ring FR is lost due to plasma processing such as etching, the height of the sheath of the focus ring FR will be lower than the height of the sheath of the wafer W. As a result, the etching rate of the edge portion of the wafer W may increase rapidly, or the etching shape may be tilted. The so-called tilt of the etched shape means that the sheath is skewed at the edge of the wafer W due to the loss of the focus ring, causing ions to be introduced into the wafer W from an oblique direction, thereby making the etched shape unable to be vertical and inclined.

In view of this, in this embodiment, as long as the focus ring FR is lost, the central focus ring 38m is pushed up by as much as possible, thereby making the wafer W and the height of the sheath on the focus ring FR consistent. Thereby, it is possible to prevent the etching rate of the edge portion of the wafer W from being soared or the etching shape from being tilted.

When controlling the amount of displacement of the piezoelectric actuator 101 in the up and down direction to become a weight (distance) corresponding to the loss of the focus ring FR, the distance corresponding to the loss of 38 m of the center focus ring is only required relative to the center focus ring. The loss of 38m can be in the range of 1 to 1.5 times. For example, the height of the central focus ring 38m during wafer W processing may be the same as the height of the inner focus ring 38i and the outer focus ring 38o, or may be up to 1.5 times the loss of the central focus ring 38m. The moving mechanism 200 pushes the center focus ring 38m up to a predetermined amount with a resolution of 0.006 mm.

For example, in the case where the loss amount of the center focus ring is 38m and it is to be controlled twice, if the loss amount of the focus ring FR is 1.0mm, the height corresponding to the loss amount of the center focus ring 38m will be 1.0. mm. Therefore, in this case, the control section 74 positions the piezoelectric actuator 101 such that the central focus ring 38m is moved upward by a factor of 1.0 mm. As a result, as shown in Figs. 4 (a-2) and (b-2), the center focus ring 38m moves upward by 1.0 mm.

In this embodiment, if the focus ring FR is a new product, the thickness of each part of the focus ring FR is as shown in FIG. 5, the thickness of the inner peripheral side of the inner focus ring 38i is 2.9 mm, and the thickness of the outer peripheral side is 1.4 mm. .

The thickness of the thickest part of the central portion of the center focusing ring 38 m is 3.9 mm, the thickness on the inner peripheral side is 2.5 mm, and the thickness on the outer peripheral side is 1.6 mm. The thickness of the outer focus ring 38o is 2.9 mm (= 1.3 mm + 1.6 mm), and the thickness of the portion with the recess 138 is 1.3 mm.

The upper limit 移动 of the moving distance of the central focus ring 38m depends on the stroke of the moving mechanism 200. In this embodiment, the stroke of the moving mechanism 200 is 0.9 mm. Therefore, even if the loss of the focus ring FR reaches 0.9 mm, as long as the moving mechanism 200 is moved to the upper limit 値, the focus ring FR can obtain the same etching characteristics as in the case of the new product.

The lower limit 移动 of the moving distance of the central focusing ring 38m is the resolution of the piezoelectric actuator 101, which is 0.006mm. In other words, when the loss of the center focus ring 38m reaches 0.006mm or more, the control unit 74 of this embodiment moves the center focus ring 38m upward by a distance corresponding to the loss amount in units of 0.006mm. When the moving distance of the center focus ring 38m reaches 0.9 mm or more, the control unit 74 controls to cause the focus ring FR to be replaced. However, the upper limit 値 of the moving distance of the center focus ring 38m is not limited to 0.9 mm, and may be set to a number 小于 smaller than 0.9 mm.

(Dimensions and materials) The size of the wafer W is 300 mm. As shown in FIG. 5, the outer diameter of the inner focus ring 38i of this embodiment is 309 mm. The ring portion 38m1 of the center focusing ring 38m in this embodiment has an inner diameter of 302 mm and an outer diameter of 316 mm. The outer diameter of the outer focus ring 38o in this embodiment is 360 mm.

However, the respective outer diameters of the inner focus ring 38i, the central focus ring 38m, and the outer focus ring 38o are not limited to the above dimensions. For example, the outer diameter of the inner focus ring 38i may be 2.5% to 3.5% larger than the outer diameter of the wafer W. In addition, the outer diameter of the center focus ring 38 m may be 4.5% to 5.5% larger than the outer diameter of the wafer W. In addition, the outer diameter of the outer focus ring 38o may be larger than the outer diameter of the wafer W by 19.5% to 20.5%.

The respective materials of the inner focus ring 38i, the central focus ring 38m, and the outer focus ring 38o are formed of any one of Si (silicon), SiO ₂ (silicon dioxide), and SiC (silicon carbide). The materials of the inner focus ring 38i, the central focus ring 38m, and the outer focus ring 38o may be the same or different.

However, the material of the central focus ring 38m is preferably harder than the materials of the inner focus ring 38i and the outer focus ring 38o. For example, if the center focus ring 38m is made of SiO ₂ or SiC, which is less prone to loss than Si, and it is difficult to wear the center focus ring 38m during processing, the etching rate will not change easily and the focus ring FR can be extended Of life.

For example, it is preferable that the material of each of the inner focus ring 38i and the outer focus ring 38o is Si, and the material of the center focus ring 38m is SiO ₂ or SiC.

[Result of Etching Rate of Three-Part Focusing Ring] Next, referring to FIG. 6 and FIG. 7, an example of the etching rate in the case of using the three-part focusing ring FR in this embodiment will be compared with a comparative example. Explain. In FIG. 6, FIG. 6 (c) shows an example of the etching rate of the focus ring FR in this embodiment, and FIGS. 6 (a) and (b) show an example of the etching rate of the focus ring FR1, FR2 of the comparative example. The diagram in FIG. 7, FIG. 7 (c) is the focus ring FR of this embodiment, and FIGS. 7 (a) and (b) are the focus rings FR1 and FR2 of the comparative example, and are used to explain the generation of plasma. .

The focus ring FR1 (Standard FR1) of the comparative example of FIG. 6 (a) is an undivided focus ring as shown in the hardware structure (HW) and Condition (condition). The focus ring FR2 (2pieces FR2) of the comparative example is a two-part focus ring. (c) The focus ring FR (3pieces FR) of this embodiment is a focus ring divided into three parts.

As shown in Condition, between the focus ring FR1 and the electrostatic chuck 36 of the comparative example of FIG. 6 (a), a polymer sheet 136 which is an insulator is sandwiched to promote heat conduction between the focus ring FR1 and the electrostatic chuck 36.

There is no polymer sheet between the focus ring FR2 of the comparative example of FIG. 6 (b) and the focus ring FR of this embodiment of FIG. 6 (c) and the electrostatic chuck 36. However, if a polymer sheet is sandwiched between the inner focus ring 38i and the outer focus ring 38o of the focus ring FR of this embodiment in FIG. 6 (c) and the electrostatic chuck 36, the focus ring FR and the electrostatic chuck are promoted. Thermal conductivity between 36 is preferred.

As shown by ER (etch rate), in any of the cases shown in Figures 6 (a) to (c), when the focus ring is new (that is, POR in Figure 6 (a), Figure 6 (b), and The etching rate at (c) of 0 mm) is uniform throughout the entire surface of the wafer W.

On the other hand, when the focus ring FR1 of the comparative example of FIG. 6 (a) is used, a 1 mm Consumption (when the focus ring loses 1 mm) of the wafer W is etched at the edge of the wafer W Soaring. Therefore, it can be seen that the etching rate cannot be controlled at the edge portion of the wafer W.

In the focus ring FR2 of the comparative example of FIG. 6 (b), the inner focus ring is fixed, and only the outer focus ring is moved up and down. In this case, the sharp increase in the etching rate at the edge portion is suppressed, and the edge portion of the wafer W can be controlled more than the focus ring FR1 of the comparative example of FIG. 6 (a). However, as the height of the outer focus ring is increased from 0 mm to 1 mm and 2 mm, the shift amount of the overall etching rate in the wafer W plane becomes larger.

On the other hand, in the focus ring FR of this embodiment in FIG. 6 (c), the inner focus ring 38i and the outer focus ring 38o are fixed, and only the center focus ring 38m is moved up and down. Thereby, the edge portion of the wafer W is controlled, and the soaring of the etching rate at the edge portion is further suppressed. In addition, even if the height of the center focus ring 38 m is increased from 0 mm to 1 mm and 2 mm, the overall etching rate in the wafer W plane does not change.

For the comparative example and the graph in the middle of FIG. 6 in this embodiment, please refer to the bottom of FIG. 6, that is, the graph that makes the etching rate at the center of the wafer W uniform. The ER% of the bottom graph is obtained by ER (x) / ER (Center) × 100. x represents the radius of the wafer W. In the lowermost graph of FIG. 6, when the focus ring FR1 of the comparative example of FIG. 6 (a) is used, the etching rate of the edge portion of the wafer W cannot be controlled. When the focus ring FR2 of the comparative example of FIG. 6 (b) is used, the etching rate of the edge portion of the wafer W can be controlled. Similarly, when the focus ring FR of this embodiment shown in FIG. 6 (c) is used, the etching rate of the edge portion of the wafer W can be controlled. However, if the focus ring FR2 is divided into two parts as shown in FIG. 6 (b), since the etching rate is increased in the middle section of the wafer W, the overall etching characteristics are changed. On the other hand, if the three-part focus ring FR of this embodiment shown in FIG. 6 (c) is used, the etching rate of the edge portion of the wafer W can be controlled without causing changes in the overall etching characteristics.

In conclusion, if the focus ring FR of this embodiment shown in FIG. 6 (c) is used, the moving distance of the center focus ring 38m will be increased in accordance with the loss of the center focus ring 38m. Thereby, on the one hand, the entire etching characteristics in the surface of the wafer W can be maintained, and on the other hand, the etching rate of the edge portion of the wafer W can be controlled. Furthermore, the problem that the etching shape is inclined at the edge portion of the wafer W can be suppressed.

By this focus ring FR, by moving the center focus ring 38m up and down in response to the loss of the center focus ring 38m, the loss of the focus ring FR can be made up and the life of the focus ring FR can be extended.

Next, the operation of the focus ring FR and the generation of the plasma will be described with reference to FIG. 7. Columns (a) and (b) of FIG. 7 schematically illustrate a mechanism for generating a plasma when the focus rings FR1 and FR2 of the comparative example are used.

The “RF Path” in FIG. 7 represents the power flow of high-frequency RF between the electrostatic chuck 36 and each of the focus rings FR, FR1, and FR2. When the focusing ring FR1 of the comparative example is used, when the sheath is flat, the high-frequency HF power generated by the plasma generated from the first high-frequency power supply 57 is transmitted to the central electrostatic chuck 36 and On the outer focus ring FR1 side, a current of almost the same degree flows, and a plasma is generated in the plasma generation space S. The etching characteristics of the generated plasma will increase the etching rate at the edge of the wafer W with the loss of the focus ring FR1.

In the case where the focusing ring FR2 of the comparative example is used, as shown in column (b) of FIG. 7, when the sheath is flat, the electric current flowing to the electrostatic chuck 36 side by the power of the high-frequency RF is more focused than the focusing current. There is more current on the ring FR1 side. The reason is as follows.

Below the outer focus ring that is pushed up, a space U1 is created. Due to the application of high-frequency RF power, an electrostatic capacitance is generated in the space U1. The electrostatic capacitance generated in the space U1 suppresses the current flow on the focus ring side. Therefore, it is easier for a current to flow on the electrostatic chuck 36 side than on the focus ring side. Therefore, compared to the case of the focusing ring FR1 shown in FIG. 7 (a), more current flows to the electrostatic chuck 36 side, and the plasma generated in the plasma generation space S will be the plasma density in the center. Higher. Accordingly, as the outer focus ring is increased in the focus ring FR2, the overall etching rate in the surface of the wafer W is increased.

In contrast, in the focus ring FR of this embodiment, as shown in FIG. 7 (c), when the height of the focus ring FR and the sheath of the electrostatic chuck 36 is the same, the high-frequency RF power flows to the electrostatic chuck 36. The current with the focus ring FR1 will be almost the same.

This is because in the focus ring FR of this embodiment, the focus ring FR is divided into three parts, and only the central focus ring 38m moves up and down, so that the vicinity of the edge portion of the wafer W, when the central focus ring 38m is pushed up, The minimum space U2 is formed. Thereby, the electrostatic capacitance generated in the space U2 is minimized, and the current flowing to the electrostatic chuck 36 side and the focusing ring FR1 side can be made to the same degree. Thus, in this embodiment, the height of the focusing ring FR and the sheath of the electrostatic chuck 36 can be made uniform by pushing up the central focusing ring 38m without causing the entire etching rate in the wafer W to shift. Thereby, the etching rate of the edge portion of the wafer W can be controlled.

As explained above, if the focus ring FR is divided into three parts according to this embodiment, only the central focus ring 38m will move up and down. This makes it possible to control the etching characteristics of the edge portion of the wafer W without changing the etching characteristics of the entire plasma treatment in the wafer W surface. This makes it possible to suppress, for example, a rapid increase in the etching rate at the edge portion of the wafer W or a tilt of the etched shape. (Focus Ring FR of Modification) Next, the focus ring FR, the movement mechanism 200, and the drive unit of the modification will be described with reference to FIG. 8. In this modification, the piezoelectric actuator 101 is also used as an example of the driving section, but the invention is not limited to this. Compared with the moving mechanism 200 of the embodiment shown in FIG. 2, the moving mechanism 200 of this modification example in FIG. 8 has been simplified, and the diameter of the central focusing ring 38 m in the radial direction has been shortened. The work table 12 is supported by a conductive cylindrical support portion 16 extending vertically upward from the bottom of the processing chamber 10 and a housing 100 provided adjacent to the inside. In this modification, the moving mechanism 200 is provided on the lower side of the electrostatic chuck 36 and is not provided on the outer peripheral side of the electrostatic chuck 36. Specifically, the electrostatic chuck 36 and the work table 12 are provided in communication with the through-hole 36c and the through-hole 12a. The pin hole of the ejector pin 102 is provided with an O-ring 110 for dividing the vacuum space and the atmospheric space. The ejector pin 102 penetrates the through-hole 12a and the through-hole 36c, and its front end portion abuts the bottom surface of the central focus ring 38m and is connected to the central focus ring 38m. The base end portion of the ejector pin 102 is fitted to the member 104a. The upper end of the piezoelectric actuator 101 is locked to the member 104a with a screw 104c; the lower end of the piezoelectric actuator 101 is locked to the member 104b with a screw 104d. Thereby, the piezoelectric actuator 101 is in contact with the ejector pin 102 and the center focus ring 38m via the member 104a. With this structure, the ejector pin 102 moves up and down in accordance with the displacement amount of the piezoelectric actuator 101 in the vertical direction. As a result, the central focus ring of 38m will move by 0.006mm as the minimum unit and only move a predetermined height. In this modification, a predetermined space is provided between the top surface of the electrostatic chuck 36 and the bottom surface of the central focus ring 38m. With this, the central focusing ring 38m can not only move upward, but also move a predetermined height downward in a predetermined space. In this modification, the moving mechanism 200 is disposed more inward than the outer peripheral ends of the electrostatic chuck 36 and the workpiece table 12, and the ejector pin 102 penetrates the inside of the workpiece table 12 and the electrostatic chuck 36. Thereby, the ejector pin 102 can lift the central focus ring 38m from directly below, and move it up and down. Furthermore, with this structure, the central focus ring 38m of this modification can be shortened in length in the diameter direction compared to the central focus ring 38m of the embodiment shown in FIG. 2. Similarly, by arranging the ejector pin 102 more inward than the outer peripheral end portions of the electrostatic chuck 36 and the work table 12, the length in the diameter direction of the member 104 a can be shortened. Thereby, the deflection of the center focus ring 38m and the deflection of the member 104a can be minimized, and the position accuracy of the center focus ring 38m in the height direction can be improved. As a result, the height of the sheath on the wafer W and the sheath on the focus ring FR can be aligned more accurately, the uniformity of the overall etching rate in the wafer W surface can be improved, and tilting can be prevented. Furthermore, the moving mechanism 200 of the present modification does not require the housing 100, the bearing portion 105, and the connecting portion 103 included in the moving mechanism 200 of the embodiment of FIG. cost. Furthermore, with the focus ring FR of this modification, a predetermined space is provided below the center focus ring 38m, thereby forming a structure in which the center focus ring 38m can move not only upward but also downward. Therefore, the lower limit 値 of the moving distance of the central focus ring 38m is the same as that of the embodiment of FIG. 2, and it is the resolution of the piezoelectric actuator 101. On the other hand, the upper limit 値 of the moving distance of the central focusing ring 38m will be smaller than "the height of a predetermined space provided between the top surface of the electrostatic chuck 36 and the bottom surface of the central focusing ring 38m, and the thickness of the central focusing ring 38m The numbers you add up. With this, the central focusing ring 38m can be moved not only upward, but also downward, and the control range of the sheath can be enlarged. Furthermore, according to the focus ring FR of this modification, compared with the focus ring FR of the embodiment shown in FIG. 2, the length in the diameter direction becomes shorter, and the length of the claw portion 38 m 2 becomes shorter. Thereby, the singularity of the electrostatic capacitance generated by the protruding structure of the 38m2 claw portion becomes smaller, and the adverse effect on the etching characteristics disappears or becomes smaller, so the uniformity of the etching rate can be further improved. In the above embodiment and modification, the height of the peak portion of the top surface of the central focus ring 38m during processing may be the same as or higher than the height of the peak portion of the top surface of the inner focus ring 38i and the outer focus ring 38o. .

As mentioned above, although the board | substrate processing apparatus was demonstrated based on the said embodiment, the board | substrate processing apparatus of this invention is not limited to the said embodiment, Various deformation | transformation and improvement are possible within the range of this invention. The matters described in the plural embodiments may be combined in a range where no contradiction occurs.

For example, although the high-frequency power RF is applied to the above embodiment, it is not limited to this, and a direct current (DC) may be applied.

Furthermore, the present invention is applicable not only to the parallel flat-plate type dual-frequency application device of FIG. 1 but also to other substrate processing devices. As for the substrate processing device, a capacitively coupled plasma (CCP) device, an inductively coupled plasma (ICP) processing device, and a plasma processing using a radial wire slot antenna can be used. Device, Helicon Wave Plasma (HWP) device, Electron Cyclotron Resonance Plasma (ECR) device, surface wave plasma processing device, etc.

Furthermore, the substrate processing apparatus may be a device that performs a predetermined process such as heat treatment of the substrate without generating plasma. The substrate processing device may or may not have an electrostatic chuck 36.

In addition, in this specification, the semiconductor wafer W is demonstrated as an example of a to-be-processed object. However, the object to be processed is not limited to this, and may be various substrates for LCD (Liquid Crystal Display), FPD (Flat Panel Display), photomask, CD substrate, printed substrate, and the like.

5‧‧‧ substrate processing equipment

10‧‧‧Processing Room

12‧‧‧Workbench

12a‧‧‧through hole

16‧‧‧ Conductive cylindrical support

16a‧‧‧space

18‧‧‧ exhaust path

20‧‧‧ Baffle

22‧‧‧ exhaust port

24‧‧‧Exhaust pipe

26‧‧‧Exhaust

27‧‧‧ moved into the exit

28‧‧‧Gate Valve

30‧‧‧The second high frequency power supply

32‧‧‧ Matcher

34‧‧‧Power Rod

36‧‧‧ electrostatic chuck

36a‧‧‧electrode

36b‧‧‧ insulating film

36c‧‧‧through hole

38i‧‧‧Inner focus ring

38m‧‧‧central focus ring

38m1‧‧‧Ring

38m2‧‧‧claw

38o‧‧‧outer focus ring

40‧‧‧DC Power

42‧‧‧Switch

43‧‧‧ Envelope

44‧‧‧Refrigerant flow path

46, 48‧‧‧ Piping

50‧‧‧Gas supply pipe

51‧‧‧jet head

52‧‧‧Gas supply hole

54‧‧‧Seal Ring

56‧‧‧Gas inlet

57‧‧‧The first high-frequency power supply

58‧‧‧ Diffusion chamber

59‧‧‧ Matcher

60‧‧‧Power line

66‧‧‧Gas supply source

74‧‧‧Control Department

100‧‧‧shell

100a‧‧‧Concave

101‧‧‧ Piezo actuator

102‧‧‧ ejector pin

103‧‧‧Connection Department

104a, 104b‧‧‧ components

104c, 104d‧‧‧screw

105‧‧‧bearing department

105a‧‧‧ recess

111, 110‧‧‧circle

136‧‧‧ molecular flakes

138‧‧‧ recess

200‧‧‧ mobile agency

Cw‧‧‧ cooling water

FR, FR1, FR2 ‧‧‧ focus ring

LF, HF‧‧‧HF

U1, U2‧‧‧ space

W‧‧‧ Wafer

[Fig. 1] A diagram showing an example of a substrate processing apparatus according to an embodiment. [FIG. 2] A diagram showing an example of a focus ring, a moving mechanism, and a driving unit according to an embodiment. [Fig. 3] (a) to (d), in one embodiment, a perspective view, a top view, and a cross-sectional view of a focusing ring divided into three parts. [Fig. 4] (a-1), (a-2), (b-1), and (b-2) are diagrams for explaining the upward and downward movement of the focus ring of an embodiment. [Fig. 5] A diagram illustrating the diameter of a focus ring according to an embodiment. [FIG. 6] (a)-(c) is a figure which shows an example of the etching rate of the focus ring of an embodiment and a comparative example. [FIG. 7] (a)-(c) is a figure explaining the plasma generation of the focus ring of one Embodiment and a comparative example. [Fig. 8] A diagram showing an example of a focus ring, a moving mechanism, and a driving unit according to a modification.

Claims (20)

A substrate processing device has a focusing ring. The focusing ring includes: an inner focusing ring, which is arranged near a substrate, and the substrate is a workpiece table placed in a processing chamber; a central focusing ring, which is arranged outside the inner focusing ring and borrows It can be moved up and down by a moving mechanism; and an outer focus ring is provided outside the central focus ring. For example, the substrate processing apparatus of the scope of application for a patent, wherein the moving mechanism moves the central focus ring to a height corresponding to a loss amount of the central focus ring. For example, the substrate processing apparatus of the scope of patent application No. 1 or 2 further includes: a housing arranged around the workpiece table and provided with the moving mechanism; and a driving part provided inside the housing and driven up and down The mobile agency. For example, the substrate processing apparatus of claim 3, wherein the plurality of driving units are connected to each other by a member, and are mounted to the housing through the member. For example, the substrate processing device of the third patent application range, wherein the lower limit 値 of the moving distance of the central focus ring is the resolution of the driving unit; the upper limit 値 of the moving distance of the central focus ring is smaller than the central focus ring Of the thickness. For example, the substrate processing apparatus of the scope of application for patents No. 1 or 2, wherein the moving mechanism penetrates the inside of the workpiece table; the substrate processing apparatus further includes a driving portion, which is arranged more inward than the outer peripheral end portion of the workpiece table. And drive the moving mechanism up and down. For example, the substrate processing apparatus of claim 6 of the patent application, wherein the plurality of driving sections are connected to each other by a member, and the moving mechanism is connected through the member. For example, the substrate processing device of the sixth scope of the patent application, wherein the lower limit 値 of the moving distance of the central focus ring is the resolution of the driving unit; the upper limit 値 of the moving distance of the central focus ring is smaller than the value set at A value obtained by adding the height of a predetermined space between the top surface of the workpiece table and the bottom surface of the central focus ring to the thickness of the central focus ring. For example, the substrate processing apparatus of claim 1 or 2, wherein the moving mechanism includes an ejector pin. For example, the substrate processing apparatus of the scope of application for patent No. 9, wherein the ejector pin is formed of sapphire. For example, the substrate processing device of the scope of application for patent No. 9, wherein the ejector pin penetrates the inside of the workpiece table and the electrostatic chuck disposed on the top surface of the workpiece table; on the top surface of the electrostatic chuck and the central focus ring There is an established space between the bottom surfaces. For example, the substrate processing apparatus in the scope of the patent application No. 5 wherein the resolution of the driving section is 0.006 mm. For example, the substrate processing apparatus of claim 3 in the patent application scope, wherein the driving unit is a piezoelectric actuator. For example, the substrate processing apparatus of the scope of application for patents No. 1 or 2, wherein the height of the peak portion of the top surface of the central focus ring in the processing chamber processing is higher than the top surfaces of the inner focus ring and the outer focus ring The peak. For example, the substrate processing apparatus of the scope of application for patents 1 or 2, wherein the inner focus ring, the central focus ring and the outer focus ring are each formed of the same material or different materials. For example, the substrate processing apparatus according to item 1 or 2 of the patent application scope, wherein the material of the inner focus ring, the central focus ring, and the outer focus ring is any one of silicon, silicon dioxide, and silicon carbide. For example, the substrate processing apparatus of claim 1 or 2, wherein the central focus ring is formed of a harder material than the materials of the inner focus ring and the outer focus ring. For example, the substrate processing device for which the scope of patent application is item 1 or 2, wherein the outer diameter of the inner focus ring is 2.5% to 3.5% larger than the outer diameter of the substrate. For example, the substrate processing apparatus for which the scope of the patent application is item 1 or 2, wherein the outer diameter of the central focus ring is 4.5% to 5.5% larger than the outer diameter of the substrate. For example, the substrate processing device of the scope of application for patents No. 1 or 2, wherein the outer diameter of the outer focus ring is larger than the outer diameter of the substrate by 19.5% to 20.5%.