TWI716725B - Plasma processing device - Google Patents

Abstract

The present invention relates to a plasma processing device, comprising an upper electrode and a lower electrode. The upper electrode has a plurality of protruding post electrodes which made by conducting material and protruded out of one surface of the upper electrode and connected to a plasma producing source. A plasma deficiency area which has no protruding post electrodes is disposed in the center part of the upper electrode. A plurality of protruding post electrodes are disposed on the outer edge of the plasma deficiency to the outer edge of the upper electrode and formed a ringlike plasma distributed area and also a plasma processing area. The lower electrode is rotatable and made of conducting material and covered with dielectric.

Description

Plasma processing device

The present invention relates to a plasma processing device, in particular to a high-efficiency large-area planar atmospheric plasma processing device that can process multiple workpieces at the same time, improve plasma uniformity and the material removal rate of the polishing process.

Silicon-based power components face the limitations of material development, and it is difficult to meet the market's new demands for high frequency, high temperature, high power, high performance, resistance to harsh environments, and portability. Silicon carbide (SiC) is a wide band gap semiconductor material with physical properties such as high withstand voltage, high saturated electron drift rate, and high thermal conductivity, and is suitable for high-power and high-temperature semiconductor components. The third-generation semiconductor materials represented by SiC will be widely used in fields including optoelectronic devices and power electronic devices; with its excellent semiconductor performance, it will be able to highlight major revolutionary functions in modern industrial fields and provide huge applications Prospects and market potential.

Although silicon carbide wafers have excellent material quality, due to the hardness and brittleness of silicon carbide (the Mohs hardness is 9.25~9.5, second only to diamond's superhard material), the material still needs to be removed in the final polishing process. With a depth of 1 to 2 microns (μm), this process takes about several hours or even more than ten hours with the traditional chemical mechanical polishing (CMP) process, which becomes a bottleneck for wafer production and high processing costs. Therefore, the upstream wafer manufacturing industry is seeking to improve the material removal rate of polishing processing of large-size (diameter ≧ 4 inches) SiC wafers.

For planar atmospheric plasma, the main consideration is that if the plasma generation in the atmosphere is set as a planar electrode, when the gap between the two electrodes is inclined, according to the Paschen's curves under the same parameter conditions, the plasma It will be naturally concentrated and generated at a position where the distance between the two electrodes is small, and cannot be redistributed after generation. Therefore, it is difficult to control the accuracy of the electrode spacing when manufacturing large-area atmospheric pressure electrodes.

Accordingly, how to have a "plasma processing device" that can process multiple workpieces at the same time, improve the plasma uniformity and the material removal rate of the polishing process, is an urgent issue for those in the relevant technical field.

In one embodiment, the present invention provides a plasma processing device, including: an upper electrode, which includes a plurality of columnar electrodes protrudingly disposed on one surface of the upper electrode and connected to a plasma source, and a central area of the upper electrode In the plasma depletion zone, there is no columnar electrode in the plasma depletion zone. A plurality of columnar electrodes are arranged from the outermost periphery of the plasma depletion zone to the periphery of the upper electrode. The plurality of columnar electrodes generate a circular plasma distribution area. A plasma treatment zone is formed from the outermost periphery of the plasma depletion zone to the periphery of the upper electrode; and the lower electrode has a built-in electrode coated with a dielectric material, and the lower electrode is grounded and driven to rotate.

10: Upper electrode

11: Seat

111: cylindrical electrode

112: Kit

113: spacer

114: The first cooling runner

1141: Inflow

1142: outflow end

115: first cover

1151: fluid inlet

1152: fluid outlet

1153: second gas inlet

116: First gas inlet

117: Second cooling runner

12: Shell

121: first hole

122: Stoma

123: second cover

13: Plasma depleted area

20, 20A: lower electrode

21, 21A: Carrier

23, 23A: cover

22, 22A: Built-in electrodes

30: Workpiece

40: Mask

41: Cavity

411: Vent Hole

412: ball

42: support frame

43: Linkage device

C1~C9: circle

D1, D2, D3, D4, D5, D6, D7, D8: diameter

F1: First direction

R1: peripheral

R2: Perimeter

X1: axial

Fig. 1 is a schematic diagram of an exploded structure of an embodiment of the present invention.

2 is a schematic diagram of an embodiment of the distribution position of the columnar electrodes of the present invention.

Fig. 3 is a schematic diagram of the A-A cross-sectional structure of Fig. 1.

Fig. 4 is a schematic structural view of an embodiment of the cooling channel of the present invention.

FIG. 5 is a schematic structural view of an embodiment of the present invention in which pores are arranged between a plurality of columnar electrodes.

FIG. 6 is a schematic diagram of a top view combined structure of an embodiment of the mask and the upper electrode and the lower electrode of the present invention.

FIG. 7 is a schematic diagram of the B-B cross-sectional structure of FIG. 6 and the mask is in the process position.

Fig. 8 is a schematic diagram of the B-B cross-sectional structure of Fig. 6 and the mask is in the feeding and discharging position.

FIG. 9 is a three-dimensional exploded structural diagram of an embodiment of the lower electrode of the present invention.

FIG. 10 is a three-dimensional exploded structural diagram of another embodiment of the lower electrode of the present invention.

Please refer to FIG. 1 for an embodiment of a plasma processing apparatus of the present invention, which includes an upper electrode 10 and a grounded and driven lower electrode 20. The upper electrode 10 can move up and down, that is, close to or separate from the lower electrode 20. The upper electrode 10 is used to provide plasma source and process gas. The lower electrode 20 functions as a platform for the workpiece 30 and as a ground electrode for plasma power supply. The area between the upper electrode 10 and the lower electrode 20 is a plasma generation area. The lower electrode 20 can be used as a ground electrode of a large-area plasma auxiliary processing device alone, or shared with a chemical mechanical polishing device, and can be used as a polishing disc of a chemical mechanical polishing device at the same time.

Please refer to FIG. 1 and FIG. 2, a plurality of columnar electrodes 111 are provided on one surface of the upper electrode 10 (that is, the bottom surface of the upper electrode 10 in the figure), and a plasma depletion region 13 is provided in the central area of the upper electrode 10. There is no columnar electrode 111 in the plasma depletion zone 13. Since there is no columnar electrode distribution in the plasma depletion zone 13, the plasma depletion zone 13 can be a blind plate or be provided with gas inlet and outlet channels. The range from the outermost periphery R1 of the plasma depletion zone 13 to the periphery R2 of the upper electrode 10 is provided with a plurality of columnar electrodes 111. The shaped electrode 111 generates an annular plasma distribution area, that is, a plasma treatment area is formed from the outermost periphery R1 of the plasma depletion region 13 to the periphery R2 of the upper electrode 11. The aforementioned annular plasma distribution area and plasma treatment area both cover the range where the workpiece 30 is placed. For example, the workpiece 30 shown in the figure is circular, and the radial width of the aforementioned annular plasma distribution area and plasma treatment area is at least equal to the diameter of the workpiece 30.

Please refer to FIG. 2 to illustrate the arrangement of the columnar electrode of the present invention. However, the illustration is only an illustrative example, and is not limited to the number and number of turns shown. The columnar electrode 111 is a conductive material covered with a dielectric material. The plurality of columnar electrodes 111 surround a circle center to form a plurality of concentric circles C1~C9. At least one columnar electrode 111 is arranged in each circle. The number in each columnar electrode 111 in the figure represents the circle in which it is located, so as to facilitate identification The columnar electrodes 111 on each circle C1~C9. The number of columnar electrodes 111 on two adjacent concentric circles is the same. For example, the first ring C1 and the second ring C2 are provided with three columnar electrodes 111, and the sixth ring C6 and the seventh ring C7 are both provided with four columnar electrodes. There are five cylindrical electrodes 111 in the eighth circle C8 and the ninth circle C9. There are five cylindrical electrodes 111 in the eighth circle C8 and the ninth circle C9; or, for two adjacent concentric circles, the number of cylindrical electrodes 111 in the outer circle is more than that in the inner circle The number of columnar electrodes 111, for example, the fifth circle C5 is provided with three columnar electrodes 111. The outer edge of the circular track formed by the cylindrical electrodes on each circle is at least tangent to the inner edge of the adjacent circular track, for example, the cylindrical electrode 111 of the first circle C1 and the third circle C3 The diameter is the same, and the radial distance between the first ring C1 and the third ring C3 is equal to the diameter of the cylindrical electrode 111, or if the radial distance between the first ring C1 and the third ring C3 is smaller than the diameter of the cylindrical electrode 111 Or, and so on. A circular plasma distribution area can be formed by the circular trajectory of the columnar electrode 111 from the first circle C1 to the ninth circle C9.

Regarding the number of columnar electrodes in each circle, the following formula can be followed: (the circle diameter * the ratio of the circumference) / the base number is rounded to an integer value. Among them, the method of determining the base is based on the following formula: (circumference length that each cylindrical electrode is responsible for in a certain circle after correction-base)/base*100%, and then select the smallest difference in the circumference of each circle. For example, when the base number is set to 80 and 100, the maximum error rate is ~9.2% (the bar numbers are 112 and 91 respectively).

When considering the expansion of the processing area, the number of outer columnar electrodes will also increase. The number of columnar electrodes with the smallest error solution may be too high, so the error rate can be increased. For example, the circumference error rate is ~10%, but the total The number of columnar electrodes is lower than when the error rate is not increased. For example, when the base is set to 110, the maximum error rate is ~10%, and the total number of columnar electrodes is 82.

When the base is different, the influence on the total number of columnar electrodes is as follows: When the base is 70:

When the base is 100:

When the base is 130:

Second, the design of the position of the columnar electrode. After obtaining the number of cylindrical electrodes in each circle according to the above, use the excel random number function rand()*360 to randomly generate angle changes to determine the distribution angle of the first cylindrical electrode in each circle, and the second to nth columns of the circle Shape electrodes, the distribution is evenly distributed. For example, if there are three cylindrical electrodes in the first circle, the spacing is 360/3=120; if there are four cylindrical electrodes in the third circle, the spacing is 360/4=90, and so on, if the angle exceeds 360 degrees Correction (minus 360 degrees); when taking random numbers, if the distance between two adjacent circles is less than the diameter of the cylindrical electrode, the random number will be retaken, and if there is an overlap, it will be moved in a full circle or a single point depending on the situation. The pattern arrangement of the columnar electrodes needs to be more evenly distributed across the entire surface to avoid regular patterns. Regular patterns (for example, the columnar electrodes of each circle are arranged on the same radial line) will form a depleted area for processing, so columnar The electrode must be adjusted to avoid this type of processing depletion zone.

Regarding the actual verification data of the above-mentioned columnar electrode adjustment, you can refer to the following table, which is the number of columnar electrodes per circle and the columnar electrode distribution position calculated with the base 110 as an example:

Secondly, a formula can be used to determine the position design of the columnar electrode. When the cylindrical electrodes in the number of turns are the same, the calculation method for the angular interval between the X-th circle and the X+1-th circle of the cylindrical electrode distribution is: 360/2n (n is the number of cylindrical electrodes in the X circle and X+1 circle) ； Among them, when n is an odd number, it is negative; when n is an even number, it is positive. Distribute the electrodes in each circle on the premise that the number of columns in each circle is evenly distributed in 360 degrees. That is, when the number of columnar electrodes is 3, the distribution pitch is 360/3=120 degrees to calculate. The number of columns in the first circle and the second circle is 3, so the difference in the arrangement of the column electrodes in the first circle and the second circle is: 360/(2*-3)=-60. Assuming that the columnar electrodes in the first circle are set at 0, 120, and 240 degrees, the column electrodes in the second circle are based on the 0 degrees of the first column electrode in the first circle, and the interval between the column electrodes is 360 Under the premise of /3=120, set at (0(360)-60)300, (300+120)60, (60+120)180 (round angle concept, 1 circle=360 degrees, 320+120=440 over One lap, so 440-360=60).

If the number of turns of x and x+1 is different, the calculation formula used is: (360/n-360/n+1); where, when n is an odd number, the front of the bracket is negative; when n is an even number, the bracket Take the front. When (360/n-360/n+1)<10, the formula is changed to: (360/n-360/n+1)*n/2; where n is an odd number, the front of the bracket is negative; n is When the number is even, the front of the parenthesis shall be positive. So the first point of the third circle is 60-(360/3-360/4)=30, and the third circle is divided into: 30, 120, 210, 300. If the number of convex points in the fourth circle is the same as that of the third circle, the distance between the first points=30+360/(2*4)=75, that is, the distribution of the fourth circle is: 75, 145, 235, 325

According to the above formula, the distribution of each point of the columnar electrode is

In summary, the distribution principle of the columnar electrodes of the present invention includes: in the annular area where the columnar electrodes are distributed, the number of columns in two adjacent circles is the same in the inner and outer rings or the outer ring is more than the inner ring; The number of columns increases from the inner ring to the outer ring; for concentric sources in two adjacent rings, the difference in diameter between the outer ring and the inner ring should not exceed twice the diameter of the cylindrical electrode, so that the inner and outer cylindrical electrodes can at least be tangent ; But the preferred design is slightly less than twice the diameter of the cylindrical electrode, so that the electrode processing area of the cylindrical inner and outer ring partially overlaps.

The rule for the number of cylindrical electrodes in each circle from the inside to the outside can include: minimum error solution: the smallest difference in the circumference of each circle is calculated after selecting the "base"; (1) the calculation method of sweeping the circumference error: error (each The circumference of the circle column number-cardinality) / cardinality * 100%; (2) Consider the second best solution of the column number setting: consider the total number of column numbers, if you consider the outer column when expanding the processing area The number of bars will also increase, and the next best solution can be selected (circumference error rate ~10%, but the total bar number is lower than the next best solution with the best error rate).

The principle of the distribution method of columnar electrodes is: (1) Each circle of columnar electrodes is evenly distributed; that is, the distribution interval is 360 degrees/n, where n is equal to the number of columnar electrodes in the circle; (2) Two adjacent circles Avoid columnar electrodes on the extension line at the same angle. When the distance between the inner and outer rings is less than 2 times the diameter, there will be partial overlap; (3) The distribution of columnar electrodes can be set by setting a certain reference point of a certain circle, adding a certain fixed value movement angle, obtaining the first point distribution angle with random numbers, and introducing a self-defined formula ( The formula is not unique) and the way of manual distribution; (4) If the first point is determined by random numbers, if the distance between two adjacent circles is less than the diameter of the columnar electrode, then the random number is retaken (to avoid overlapping columnar electrodes ); (5) The distribution of the columnar electrodes must be evenly distributed toward the entire disk surface to avoid the formation of regular patterns.

Solutions for overlapping adjacent circles: (1) The setting of the integral cylindrical electrode of the inner ring or the outer ring moves an angle at the same time; (2) The remaining points do not move, and the overlap point moves so that the two adjacent points are staggered (the distance between the center of the circle and the center of the circle is at least Equal to the diameter of the columnar electrode).

Please refer to FIG. 1 and FIG. 3, the upper electrode 10 includes a base 11 made of conductive material and a housing 12 made of dielectric material. A plurality of columnar electrodes 111 are provided on one surface of the seat body 11 (that is, the bottom surface of the seat body 11 in the figure). The columnar electrodes 111 are protrudingly arranged on one surface of the seat body 11 of the upper electrode 10 and are connected to a plasma source. Each column electrode 111 is a cylinder, and its axial end faces the lower electrode 20. As shown in FIG. 3, the columnar electrode 111 is integrally formed with the seat body 11. In addition, the columnar electrode 111 and the seat body 11 can also be fixed by a connecting member, for example, arranged on the top of the columnar electrode 111 A protruding column extends into the seat body 11 and is fixed with a C-ring. Each cylindrical electrode 111 is sheathed with a dielectric kit 112. A plurality of first holes 121 are provided at the position of the housing 12 corresponding to the plurality of columnar electrodes 111, the seat 11 is disposed in the housing 12, and the plurality of columnar electrodes 111 of the sleeve 112 are covered by the corresponding first holes 121 protrudes outside the housing 12. A plurality of pores 122 are distributed in the range of the plasma depletion region 13 of the upper electrode 10. A spacer made of dielectric material is provided on the surface of the base body 11 with a plurality of columnar electrodes 111 113, for example, ceramic sheet, Teflon sheet. A first cooling channel 114 and a first gas inlet 116 are provided on the seat body 11 opposite to the surface on which the plurality of columnar electrodes 111 are provided (that is, the top surface of the seat body 11 in the figure). A second cooling channel 117 is provided at the axial center of each cylindrical electrode 111 to communicate with the first cooling channel 114 to form a cooling path.

Please refer to FIG. 3 and FIG. 4, the first cooling channel 114 is a continuous channel, which has an inflow end 1141 and a first flow out end 1142. A first cover 115 made of conductive material is provided on the surface of the base body 11 opposite to the surface where the plurality of columnar electrodes 111 are provided to cover the first cooling channel 114. The first cover 115 is provided with a fluid inlet 1151, a fluid outlet 1152 and a second gas inlet 1153, and the second gas inlet 1153 communicates with the gas hole 122 through the first gas inlet 116. The cooling fluid enters the inflow end 1141 from the fluid inlet 1151, and then flows out of the first cooling channel 114 from the outflow end 1142 via the fluid outlet 1152. In addition, the housing 12 has a second cover 123 made of dielectric material, which is disposed on the surface of the housing 12 opposite to the surface where the plurality of columnar electrodes 111 are provided, and covers the first cover 115. After the second cover plate 123 is sealed, the first cooling channel 114 and the second cooling channel 117 can form a closed circulating channel, and fluid can be introduced to cool the upper electrode 10 to maintain the temperature of the upper electrode 10.

Please refer to FIG. 5, which shows an example structure of an air intake method in which pores 122 are arranged between a plurality of columnar electrodes 111, which is different from that shown in FIG. 3 where pores 122 are arranged in the range of the plasma depletion zone 13 Examples.

Please refer to FIG. 1 and FIG. 5, the upper electrode 10 includes a base 11 made of conductive material and a housing 12 made of dielectric material. A plurality of columnar electrodes 111 are provided on one surface of the seat body 11 (that is, the bottom surface of the seat body 11 in the figure). The columnar electrodes 111 are protrudingly arranged on one surface of the seat body 11 of the upper electrode 10 and are connected to a plasma source. Each column electrode 111 is a cylinder, and its axial end faces the lower electrode 20. As shown in Figure 5, the columnar electrode 111 is integrally formed with the base body 11. In addition, it can also be connected to the fixing method. The cylindrical electrode 111 and the seat body 11 are combined in a similar manner. For example, a protrusion is arranged on the top of the cylindrical electrode 111 to extend into the seat body 11 and then fixed by a C-ring. Each cylindrical electrode 111 is sheathed with a dielectric kit 112. A plurality of first holes 121 are provided at the position of the housing 12 corresponding to the plurality of columnar electrodes 111, the seat 11 is disposed in the housing 12, and the plurality of columnar electrodes 111 of the sleeve 112 are covered by the corresponding first holes 121 protrudes outside the housing 12. A plurality of pores 122 are distributed between the plurality of columnar electrodes 111. A spacer 113 made of dielectric material, such as a ceramic sheet or a Teflon sheet, is provided on the surface of the base body 11 where the plurality of columnar electrodes 111 are provided. A first cooling channel 114 and a first gas inlet 116 are provided on the seat body 11 opposite to the surface on which the plurality of columnar electrodes 111 are provided (that is, the top surface of the seat body 11 in the figure). A second cooling channel 117 is provided at the axial center of each cylindrical electrode 111 to communicate with the first cooling channel 114 to form a cooling path.

Please refer to FIG. 4 and FIG. 5, the first cooling channel 114 is a continuous flow channel, which has an inflow end 1141 and a first flow out end 1142. A first cover 115 made of conductive material is provided on the surface of the base body 11 opposite to the surface where the plurality of columnar electrodes 111 are provided to cover the first cooling channel 114. The first cover 115 is provided with a fluid inlet 1151, a fluid outlet 1152 and a second gas inlet 1153. The cooling fluid enters the inflow end 1141 from the fluid inlet 1151, and then flows out of the first cooling channel 114 from the outflow end 1142 via the fluid outlet 1152. The process gas passes through the second gas inlet 1153 and the first gas inlet 116 from the outside, and then flows out of the housing 12 through a plurality of air holes 122 respectively, and flows to the plasma generation area between the upper electrode 10 and the lower electrode 20. In addition, the housing 12 has a second cover 123 made of dielectric material, which is disposed on the surface of the housing 12 opposite to the surface where the plurality of columnar electrodes 111 are provided, and covers the first cover 115. After the second cover plate 123 is sealed, the first cooling channel 114 and the second cooling channel 117 can form a closed circulating channel, and fluid can be introduced to cool the upper electrode 10 to maintain the temperature of the upper electrode 10.

It must be noted that the housing 12 made of dielectric material, the set 112 made of dielectric material, the spacer 113 made of dielectric material, and the second cover plate 123 made of dielectric material used in the above embodiment are used to make each The columnar electrode 111 uniformly excites the plasma, and prevents the charged particles from directly bombarding the conductive electrode when the plasma is generated to form arc discharge damage to the electrode. However, the technical means that can be used to achieve this objective are not limited to this. For example, the housing 12 and the assembly 112 can be combined into a dielectric material that entirely covers the upper electrode 10 and the columnar electrode 111. In addition, FIGS. 1 to 5 respectively show the three-dimensional, bottom-view, and cross-sectional structures of the upper electrode, which are only schematic diagrams and not drawn to scale.

Please refer to FIG. 6 and FIG. 7, a shield 40 is provided between the upper electrode 10 and the lower electrode 20. The shield 40 includes a cavity 41, a support frame 42 and a linkage device 43. The cavity 41 is ring-shaped, and its inner diameter is larger than the outer diameters of the upper electrode 10 and the lower electrode 20. The cavity 41 is provided with at least one air hole 411, and the cavity 41 is provided with a valve (not shown in the figure) to control the process gas in and out of the cavity. The direction of the body 41. The material of the cavity 41 is not limited, and may be metal or dielectric material. The support frame 42 is arranged on the top of the cavity 41. The support frame 42 is in a hollow ring shape and is used as an upper baffle. The material of the support frame 42 is not limited, and can be metal or dielectric material. The linkage device 43 is connected to the cavity 41 and can drive the cavity 41 and the support frame 42 to move synchronously.

Please refer to FIGS. 3 and 7, the second gas inlet 1153, the first gas inlet 116, the air hole 122 of the upper electrode 10, the plasma generation area between the upper electrode 10 and the lower electrode 20, the air hole 411 of the cavity 40, A connected process gas passage is formed inside the cavity 41. According to this, if the second gas inlet 1153 is connected to a gas mixing tank for a process gas, and the cavity 41 is connected to an exhaust gas treatment system, the process gas can be introduced into the first The second gas inlet 1153 flows through the first gas inlet 116, the air hole 122 of the upper electrode 10, the plasma generation area between the upper electrode 10 and the lower electrode 20, the air hole 411 of the cavity 40, and the inside of the cavity 41, and then discharges to the exhaust gas Processing system. At this time, the air hole 122 is an air supply port, and the air hole 411 is an air suction port. The flow direction of the process gas is shown in the direction of the arrows in FIGS. 3 and 7.

Conversely, if the cavity 41 is connected to a gas mixing tank for a process gas, and the second gas inlet 1153 is connected to an exhaust gas treatment system, the process gas can be introduced into the cavity 41 and flow through the air holes 411 of the cavity 40 After the plasma generation area between the upper electrode 10 and the lower electrode 20, the air holes 122 of the upper electrode 10, the first gas inlet 116, and the second gas inlet 1153, they are discharged to the exhaust gas treatment system. The direction of the process gas entering and exiting the cavity is controlled by the valve of the cavity 41. At this time, the air hole 411 is an air supply port, and the air hole 122 is an air suction port. The flow direction of the process gas is opposite to the arrow direction shown in FIGS. 3 and 7.

Please refer to Figures 7 and 8, the linkage device 43 controls the cavity 41 to move back and forth parallel to the first direction F1 between a process position (position shown in Figure 7) and a feeding and discharging position (position shown in Figure 8). A plurality of balls 412 are provided on the inner side of the cavity 41 to contact the outer edge of the upper electrode 10, and are used to guide the shield 40 to move up and down. The first direction F1 is parallel to the axial direction X1 of the columnar electrode 111 and perpendicular to the horizontal plane. As shown in FIG. 7, when the cavity 41 is in the process position, the lower edge of the cavity 41 is aligned with or lower than the bottom surface of the bottom electrode 20. As shown in Fig. 8, when the linkage device 43 lifts the cavity 41 up to position the cavity 41 at the feeding and discharging position, the lower edge of the cavity 41 is higher than the top surface of the lower electrode 20, so that the lower electrode 20 can be processed by plasma The zone is moved out to replace the new workpiece 30 to be subjected to plasma treatment, and then the interlocking device 43 lowers the cavity 41 to the process position shown in FIG. 9 to perform the plasma operation of the workpiece 30.

The functions of the shield 40 provided in the present invention include: (1) Cover the space between the upper and lower electrodes, stabilize the gas composition, and avoid the influence of external air; (2) Have ventilation and exhaust holes, which can quickly replace the residual reaction gas after the process is completed ; (3) It has a guiding device that does not interfere with loading and unloading; (4) A gas guide (or exhaust hole) can be set to change the process gas intake mode. When using this method, you can The air hole 122 is omitted.

Please refer to the embodiment shown in FIG. 9, the lower electrode 20 includes a carrier 21, a cover 23 and a built-in electrode 22. The built-in electrode 22 is a ring-shaped member, and the carrier 21 and the cover 23 are dielectric Material, sandwich the built-in electrode 22 between them and wrap the built-in electrode 22 outside.

Please refer to Figures 2 and 9, the central circular area of the circular track formed by the built-in electrode 22 corresponds to the plasma depletion zone 13. The diameter of the circular track formed by the built-in electrode 22 D1 is equal to or greater than the outer diameter D2 of the circular track formed by the cylindrical electrode 111 at the outermost periphery, and the inner diameter of the circular track formed by the built-in electrode 22 is the diameter of the circular track D3 (also That is, the inner diameter D3 of the built-in electrode 22 is equal to or smaller than the inner diameter D4 of the circular track formed by the cylindrical electrode 111 at the innermost circumference. It must be noted that the reason why the built-in electrode 22 is designed as a ring in this embodiment is that since the plasma depletion region 13 of the upper electrode 10 does not generate plasma, the lower electrode 20 corresponds to the plasma of the upper electrode 10. The position of the depletion zone 13 does not need to be provided with a lower electrode, which can save cost. In other words, the built-in electrode 22 can also be provided as a circular piece without considering the cost.

Please refer to FIG. 10, the lower electrode 20A includes a carrier 21A, three lids 23A, and three built-in electrodes 22A. The built-in electrode 22A is a circular piece, and the carrier 21A and the lid 23A are made of dielectric material. , The built-in electrode 22A is sandwiched therebetween and covered outside the built-in electrode 22A. However, the number of built-in electrodes 22A is not limited to three.

Please refer to Figures 2 and 10, the central circular area of the circular track formed by the built-in electrode 22A corresponds to the plasma depletion zone 13. The diameter of the circular track formed by the built-in electrode 22A D5 is equal to or greater than the outer diameter D2 of the circular track formed by the cylindrical electrode 111 located at the outermost periphery, and the inner diameter of the circular track formed by the built-in electrode 22A is the diameter of the circular track The diameter D6 is equal to or smaller than the inner edge diameter D4 of the circular track formed by the cylindrical electrode 111 located at the innermost circumference. The diameter D7 of the built-in electrode 22A is equal to or greater than the diameter D8 of the workpiece 30 to be processed.

In this embodiment, the built-in electrode 22A is designed as a circular piece, and the workpiece only needs to be placed at a position where the built-in electrode 22A is provided, as shown in FIG. 1. Therefore, compared with the embodiment shown in FIG. 9, this embodiment can further reduce the manufacturing cost of the bottom electrode; in addition, the user can determine the number of built-in electrodes 22A, for example, three inner electrodes can be installed as shown in FIG. The Tibetan electrode 22A can also be provided with only one or two; when three built-in electrodes 22A are provided, one workpiece and two workpieces can be processed at a time as required, and a maximum of three workpieces can be processed; when two are provided With the built-in electrode 22A, one workpiece or two workpieces can be processed at a time as required. Plasma is generated only when the workpiece is placed in the corresponding position of the built-in electrode, which can reduce power consumption.

Figures 9 and 10 show that the built-in electrode of the present invention can be composed of a single ring member or a plurality of circular members, so that the electrode protrusions can generate plasma at all times or from time to time.

According to the above design principles, it can be concluded that the setting criteria of the plasma depletion zone 13 of the present invention include: (1) Confirm the size of the lower electrode 20, for example, the diameter is 355mm, or other dimensions; (2) Confirm the workpiece 20 to be processed For example, a wafer with a diameter of 4 inches, or other size workpieces; (3) the outermost columnar electrode 111 distribution: equal to or slightly larger than the innermost layer of the inner electrode 22, 22A distribution periphery; (4) the innermost layer Distribution of the columnar electrodes 111: equal to or slightly smaller than the lower electrode 20.

In summary, the plasma processing device of the present invention is a large area atmospheric plasma processing device that can be used for hard and brittle materials (such as silicon carbide) to improve polishing efficiency. The reactive species generated by plasma dissociation gas produce physical and chemical reactions with the surface of hard and brittle materials to achieve the effect of surface modification or form volatile species to remove from the surface, and solve the problem of mechanical chemical polishing in the hard and brittle material surface polishing process removal Too low efficiency leads to the problem of high processing costs. The invention includes: an upper electrode with an asymmetrical columnar structure, the columnar electrodes are arranged to form a circular plasma processing area; a lower electrode with a built-in electrode, the design of the built-in electrode matches the ring shape of the upper electrode The plasma processing area is set up. When a high-frequency plasma source (such as RF) is excited on the upper electrode, plasma is generated at the convex pillar structure of the upper electrode and the corresponding built-in electrode of the lower electrode. The bottom electrode is connected with a device that can provide rotational kinetic energy, and the speed of rotation can be adjusted. When the bottom electrode rotates, the cylindrical electrode distribution design in the annular area of the top electrode enables the plasma processing range to cover the entire processing surface to achieve multiple workpieces (For example, multiple SiC wafers) the target of simultaneous processing. The plasma system used in the present invention is generated in the atmosphere, has a large area and does not require a vacuum chamber, but a movable shield is arranged between the upper and lower electrodes to reduce the interference of the external environment and quickly remove the process gas after the process is completed.

In addition, the present invention is dry processing and can be carried out in an atmospheric environment, and is easy to integrate with mechanical chemical polishing equipment. Experimental verification shows that the polishing removal efficiency (the best at this stage) of commercially available 4-inch silicon carbide hard and brittle wafer materials has been increased from 0.23 to 1.51um/hr (657% increase).

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.

10‧‧‧Upper electrode

111‧‧‧Cylinder electrode

12‧‧‧Shell

122‧‧‧Stomata

123‧‧‧Second cover

13‧‧‧Depleted area of plasma

20‧‧‧Lower electrode

21‧‧‧Carrier

30‧‧‧Workpiece

Claims (16)

A plasma processing device includes: an upper electrode, which includes a plurality of columnar electrodes protrudingly arranged on one surface of the upper electrode and connected to a plasma source, and a plasma depletion region is provided in the central area of the upper electrode. There is no columnar electrode in the plasma depletion zone, and a plurality of the columnar electrodes are arranged from the outermost periphery of the plasma depletion zone to the periphery of the upper electrode. The plurality of columnar electrodes generate a circular plasma distribution zone. A plasma treatment zone is formed from the outermost periphery of the plasma depletion zone to the periphery of the upper electrode; the plurality of columnar electrodes form a plurality of concentric circles around a circle center, and at least one columnar electrode is provided in each circle, wherein each The outer edge of the circular trajectory formed by the cylindrical electrode on a circle is at least tangent to the inner edge of the adjacent circular trajectory, and the circular trajectory of the plurality of circular cylindrical electrodes forms the circular plasma Distribution area; and a lower electrode, which has a built-in electrode coated with a dielectric material, and the lower electrode is grounded and driven to rotate. The plasma processing device described in item 1 of the scope of patent application, wherein the built-in electrode is a ring-shaped piece or at least a round piece, and the center circular area of the circular track formed by it corresponds to the electric In the slurry depletion zone, the diameter of the circular track formed by it is equal to or greater than the outer diameter of the circular track formed by the columnar electrode located at the outermost periphery. The plasma processing device described in item 2 of the scope of patent application, wherein the built-in electrode is a ring-shaped piece with an inner edge diameter equal to or smaller than the circular track formed by the cylindrical electrode at the innermost circumference Inner edge diameter. In the plasma processing device described in item 2 of the scope of patent application, the built-in electrode is composed of a plurality of circular pieces arranged in a ring shape. The plasma processing device described in item 2 of the scope of patent application, wherein the built-in electrode The diameter of is equal to or greater than the diameter of the pretreated workpiece. The plasma processing device according to the first item of the scope of patent application, wherein the upper electrode includes a base body made of conductive material, the plurality of columnar electrodes are arranged on one surface of the base body, and the base body is provided with a first cooling channel ; The axial center of each columnar electrode is provided with a second cooling channel communicating with the first cooling channel to form a cooling path. In the plasma processing device described in item 1 of the scope of patent application, a plurality of pores are distributed in the range of the plasma depletion zone. The plasma processing device described in item 1 of the scope of patent application, wherein a shield is provided between the upper electrode and the lower electrode, and the shield includes: a cavity in a ring shape with an inner diameter larger than the upper electrode With the outer diameter of the lower electrode, the cavity is provided with at least one air hole; a support frame, which has a hollow ring shape, is connected to the cavity; and a linkage device, which drives the cavity to move synchronously with the support frame. The plasma processing device described in item 8 of the scope of patent application, wherein the pores of the upper electrode, the plasma generating area between the upper electrode and the lower electrode, the pores of the cavity, and the inside of the cavity form a connection Through the process gas path. In the plasma processing device described in claim 9, wherein one of the pores of the upper electrode and the inside of the cavity is connected to a gas mixing tank for process gas, and the other is connected to an exhaust gas processing system. The plasma processing device described in item 8 of the scope of patent application, wherein the cavity is provided with a valve to control the direction of the process gas in and out of the cavity. The plasma processing device described in item 8 of the scope of patent application, wherein the linkage device Control the cavity to move reciprocally between a process position and a material feeding and discharging position in parallel to a first direction, the first direction being parallel to the axial direction of the columnar electrode and perpendicular to the horizontal plane, when the cavity is at the process position, The lower edge of the cavity is aligned with or higher than the top surface of the lower electrode. When the cavity is located at the feeding and discharging position, the lower edge of the cavity is higher than the top surface of the lower electrode. In the plasma processing device described in item 8 of the scope of patent application, the material of the cavity and the support frame is metal or dielectric material. According to the plasma processing device described in item 1 of the scope of patent application, the plurality of columnar electrodes are conductive materials covered with dielectric materials. The plasma processing device described in the first item of the scope of patent application, wherein the number of the columnar electrodes on the concentric circles of two adjacent circles is the same. In the plasma processing device described in item 1 of the scope of the patent application, the number of the columnar electrodes located on the outer ring of the concentric circles of two adjacent circles is greater than the number of the columnar electrodes located on the inner ring.

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