JP2022145477A - Work-piece processing device - Google Patents

Abstract

To provide a work-piece processing device capable of realizing a high processing rate and stably processing a work-piece formed using a difficult-to-process material in a short time.SOLUTION: In a work-piece processing device 1 according to the present invention that performs processing by bringing a processing head 14 into sliding contact with a work-piece W held on the upper surface of a holding plate 20, the processing head 14 includes a plasma electrode 30 that is rotatably provided and generates plasma and irradiates the surface of the work-piece W to be processed. The plasma electrode 30 is divided into a plurality of divided electrodes 32 in the circumferential direction, and a slit portion 36 provided between adjacent divided electrodes is configured as a plasma generation space, and a processing pad 40 is provided on the bottom surface of each divided electrode 32.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a work processing apparatus, and more particularly, to a work processing apparatus that processes a surface of a work held by a holding plate by bringing a processing head into sliding contact with the work.

Surface processing is essential for substrates (workpieces) exemplified by wafers in fabricating semiconductor power devices. In particular, since wide bandgap semiconductor substrates represented by silicon carbide (SiC), gallium nitride (GaN), and diamond are hard and fragile, there is a problem that high-efficiency processing is difficult with conventional mechanical processing. In addition, "processing" in the present application broadly includes processing for removing the surface, such as grinding for shaving the surface, polishing for reducing surface roughness, and flattening for increasing flatness.

When processing the substrate, it is conceivable to use a processing method called P-CVM (Plasma Chemical Vaporization Machining). This method is a chemical processing method using plasma under atmospheric pressure, and its high radical density enables highly efficient processing. However, this is a processing method that performs isotropic etching, and since it processes not only the convex portions of the surface but also the concave portions of the surface, it is not suitable for the purpose of flattening.

Therefore, in Patent Document 1 (Japanese Patent Laid-Open No. 2015-159257), Patent Document 2 (Japanese Patent Laid-Open No. 2015-179830), etc., silicon carbide (SiC), gallium nitride (GaN), diamond and other difficult-to-process materials Therefore, a method and apparatus for highly efficient and highly accurate processing by combining plasma processing and machining are disclosed.

JP 2015-159257 A JP 2015-179830 A

However, in the conventional work processing apparatus exemplified in Patent Document 1, a mechanical section for performing CMP (Chemical Mechanical Polishing) and a mechanical section for performing plasma processing are separately arranged. Since the machining is alternately repeated, the takt time becomes long and the production efficiency decreases.

On the other hand, in the conventional work processing apparatus exemplified in Patent Document 2, since the mechanism part that performs plasma processing is built into the surface plate, the slurry sticks at the built-in location, and the influence of the slurry There were problems such as unstable plasma generation depending on (wet environment).

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a work processing apparatus capable of achieving a high processing rate and stably processing a work made of a difficult-to-process material in a short period of time. intended to

The present invention solves the above-described problems by means of solving means described below as one embodiment.

A work processing apparatus according to the present invention is a work processing apparatus for processing a surface to be processed by bringing a processing head into sliding contact with a work held on an upper surface of a holding plate, wherein the processing head is rotatable. and a plasma electrode for generating plasma and irradiating the surface to be processed of the workpiece, wherein the plasma electrode is divided into a plurality of divided electrodes in the circumferential direction, and between the adjacent divided electrodes It is a requirement that a slit portion provided in is configured as a plasma generation space, and that a processing pad is provided on the bottom surface of each of the divided electrodes.

According to the present invention, even a workpiece formed using a difficult-to-process material can be processed while modifying and etching the surface to be processed, so that the processing rate can be increased. In addition, plasma processing and processing can be performed at the same time, that is, in a continuous process without rearranging workpieces between mechanisms. It becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS It is front sectional drawing which shows the example of the workpiece processing apparatus which concerns on 1st embodiment of this invention. FIG. 2 is a sectional view taken along line II-II in FIG. 1; 2 is an enlarged view showing an example of a machining head in the workpiece machining apparatus of FIG. 1; FIG. 3 is a cross-sectional view showing another example of a machining head in the work machining apparatus of FIG. 1; FIG. FIG. 2 is a perspective view showing an example of a plasma electrode of a machining head in the workpiece machining apparatus of FIG. 1; 3 is a perspective view showing another example of the plasma electrode of the machining head in the workpiece machining apparatus of FIG. 1; FIG. 3 is a perspective view showing another example of the plasma electrode of the machining head in the workpiece machining apparatus of FIG. 1; FIG. 3 is a perspective view showing another example of the plasma electrode of the machining head in the workpiece machining apparatus of FIG. 1; FIG. 3 is a cross-sectional view showing another example of a plasma electrode of the machining head in the workpiece machining apparatus of FIG. 1; FIG. FIG. 5 is a front cross-sectional view showing an example of a work processing device according to a second embodiment of the present invention; FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10; FIG. 11 is a cross-sectional view showing another example of a machining head in the work machining apparatus of FIG. 10; FIG. 11 is a cross-sectional view showing another example of a machining head in the work machining apparatus of FIG. 10; FIG. 11 is a cross-sectional view showing another example of a machining head in the work machining apparatus of FIG. 10; 10 is an enlarged view of the XV part in FIG. 9. FIG. 3 is a diagram visualizing the intensity of plasma generation in the samples shown in Table 1. FIG. 3 is a cross-sectional view showing another example of a plasma electrode of the machining head in the workpiece machining apparatus of FIG. 1; FIG.

(First embodiment)
A first embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a front cross-sectional view (schematic diagram) showing an example of a work processing apparatus 1 according to this embodiment. 2 is a cross-sectional view (schematic diagram) taken along the line II--II in FIG. 3 is an enlarged view (schematic view) of the machining head 14 in the workpiece machining apparatus 1 of FIG. In addition, in all the drawings for explaining each embodiment, members having the same function are denoted by the same reference numerals, and repeated description thereof may be omitted.

The work processing apparatus 1 according to the present embodiment is a device for processing (surface processing) a work W on a holding plate 20 fixed to the upper surface of a rotary table 12 by pressing a processing head 14 into sliding contact with the work W. be.

On the other hand, the workpiece W to be processed is a substrate (as an example, a disk-shaped wafer) formed using so-called difficult-to-process materials such as silicon carbide (SiC), gallium nitride (GaN), and diamond. The outer diameter and thickness are not particularly limited (for example, the outer diameter is about several centimeters to several tens of centimeters, and the thickness is about several μm to several mm).

Further, the holding plate 20 according to the present embodiment holds (sticks) one or more works W on the holding surface (upper surface), and the surface to be processed (upper surface) of the works W is used for the work processing of the processing head 14 . It acts to abut on the surface (lower surface). In this embodiment, the lower surface of the work W is adhered to the holding surface (upper surface) of the holding plate 20 by a known peelable adhesive, but the present invention is not limited to this. A method such as fitting by forming a recess may be used. The holding plate 20 is required to have high flatness accuracy and be made of a material that is difficult to deform, and is generally made of glass, ceramics, or the like.

Next, the turntable 12 according to the present embodiment is formed in a circular shape in plan view using a metal material (eg, a stainless alloy, etc.), and is supported by a bearing 44 to support a driving device (eg, an electric motor). (in the direction of arrow A). The holding plate 20 is held (fixed) at a predetermined position on the turntable 12 via a carrier 22 . This carrier 22 is generally formed using a metal material (eg, a stainless alloy, etc.).

Here, the carrier 22 is meshed with the sun gear 16 and the internal gear 18 which are arranged so as to coincide with the central axis of the rotary disc 12, and is rotated by the rotation of the rotary disc 12. (in the direction of arrow C) and revolves (in the direction of arrow D). The rotation of the carrier 22 causes the holding plate 20 to rotate (in the direction of arrow C) and revolve (in the direction of arrow D). In this embodiment, four carriers 22 are arranged between the sun gear 16 and the internal gear 18, but the configuration is not limited to this.

Next, the processing head 14 according to the present embodiment is supported at a position above the turntable 12 so as to be vertically movable, and is driven by a driving device (not shown) such as an electric motor disposed on the support frame 10 . It is configured to be rotatable (in the direction of arrow B). As an example, it is configured by a known mechanism including splines or the like. In addition, the lower surface is configured as a work processing surface for processing the work W, and is further provided with a plasma electrode 30 for generating plasma and irradiating the surface of the work W to be processed.

Here, the plasma electrode 30 according to the present embodiment is divided into a plurality of split electrodes 32, and slit portions 36 provided between adjacent split electrodes 32 are configured as plasma generation spaces (details described later). A processing pad 40 is provided on the bottom surface of each split electrode 32 .

The plasma is generated by supplying a base gas (rare gas such as He) and a reaction gas from each reservoir (not shown) to the slit portion 36 through the pipe 46, and generating a predetermined voltage between the adjacent electrodes forming the slit portion 36. can be generated by applying Specific examples of the reaction gas include fluorine-based gas and oxygen gas when the workpiece is SiC, etc., chlorine-based gas and oxygen gas when the workpiece is GaN, and fluorine gas when the workpiece is diamond. A system gas, oxygen gas, or hydrogen gas is preferably used.

According to the above configuration, the holding plate 20 can be rotated and revolved via the carrier 22 by rotating (rotating) the turntable 12 . At the same time, the machining head 14 can be rotated (rotated) so as to be pressed against and slidably contacted with the workpiece W held by the holding plate 20 . At this time, plasma can be generated by the rotating plasma electrode 30 to irradiate the surface of the workpiece W to be processed. Therefore, the surface of the work W to be processed can be processed while being modified or etched (both or one of them depending on the material of the work W and the type of reaction gas) by plasma irradiation. can be improved. Compared to an apparatus that alternately performs a plasma processing step and a processing step using separately arranged mechanisms as exemplified in Patent Document 1, according to the present embodiment, these steps are performed simultaneously, that is, the workpiece W Since the processing can be carried out continuously without requiring rearrangement or the like, processing can be performed in a short period of time, and production efficiency can be improved.

In the work processing apparatus 1 according to the present embodiment, the slit portion 36 can pass through the entire region of the processed surface of all the works W whose positions are relatively changed by the movement (rotation) of each mechanism, and the processing pad A plurality of (for example, two) processing heads 14 are arranged with an outer diameter and an arrangement that allow sliding contact with the head 40 . According to this, the processing rate can be improved, and processing can be performed in a short time. However, the number of processing heads 14 to be arranged is not limited to the above, and as a modified example, three or more may be arranged (not shown).

As yet another modified example, as shown in FIG. 4 (a cross-sectional view at a position corresponding to FIG. 2), one processing head 14 may be provided. In this case, the device may be simplified by adopting a configuration in which the holding plate 20 does not revolve but only rotates (not shown).

Further, the work processing device 1 according to the present embodiment is configured to include a slurry supply device for supplying slurry (not shown). According to this, it is possible to appropriately set the supply (including non-supply) of the slurry in the machining process according to the material of the workpiece W and the machining conditions.

Next, an embodiment of the plasma electrode 30 provided on the processing head 14 will be described in detail. The plasma electrode 30 according to the present embodiment is formed in a circular shape when viewed from the bottom, and is symmetrical with respect to the axial center point S. ) divided into split electrodes 32 . As described above, the slit portion 36, which is a space portion provided between the split electrodes, is configured as a plasma generation space. Therefore, usually, an even number of split electrodes are provided so that adjacent split electrodes have different polarities. Although the constituent material of the split electrodes 32 is not particularly limited, the split electrodes 32 are formed using a conductive material.

As a specific configuration example, regarding the plasma electrode 30 having a plurality of split electrodes 32 that are symmetrical with respect to the axial center point S, FIG. FIG. 7 shows the case of eight. However, it is not limited to these numbers. By the way, it can be said that these examples are configurations equally divided in the circumferential direction. 9 to 14 below, the configuration of FIG. 6 is used as an example.

According to such a configuration, plasma can be generated in the slit portion 36 provided between the split electrodes, and the surface of the workpiece W to be processed can be irradiated with the plasma. Therefore, as the number of slits 36 set in the circumferential direction increases, the number of times plasma is generated (irradiation amount) per rotation of the processing head 14 can be increased, and the processing surface of the workpiece W can be modified and etched. can be increased, and the processing rate and production efficiency can be further improved.

On the other hand, irrespective of the number of split electrodes 32, the processing pad 40 provided on the bottom surface is, as shown in FIG. ) to extend outward (in a direction intersecting the side surface) by a predetermined length and to have an upwardly inclined extension portion 40a. According to this, when the bottom surface of the rotating processing head 14 presses and slides against the work W, the edge of the work W can be pushed under the extending portion 40a. can be prevented from coming into contact with the edge and peeling off.

Next, modified examples of the plasma electrode 30 will be described. Specifically, as shown in FIG. 8, a plate-shaped or block-shaped additional electrode 34 is provided in the slit portion 36 in parallel with the electrode surface of the split electrode 32 . That is, in plan view, the additional electrode 34 divides the slit portion 36 into spaces in the circumferential direction, and each space is configured as a plasma generation space. In addition, although the constituent material of the additional electrode 34 is not particularly limited, it is formed using a conductive material.

With such a configuration, the number of slit portions 36 provided, that is, the plasma generation space can be increased without increasing the number of split electrodes 32 provided in the processing head 14 . It is possible to increase the number of plasma generation times (irradiation amount) per rotation in the work W, enhance the modification action and etching action of the processed surface of the work W, and further improve the processing rate and production efficiency. Become.

Another modified example of the plasma electrode 30 will be described. Specifically, as shown in FIG. 9 (a cross-sectional view of a position corresponding to FIG. 3), at least one of the two side surfaces 32a and 32b facing each other via the slit portion 36 (FIG. A protruding portion 38 is provided at the lower end position of the configuration example) so as to protrude in a direction to reduce the interval dimension (circumferential dimension) of the slit portion 36 .

According to such a configuration, plasma can be generated intensively at the position of the projecting portion 38 of the plasma electrode 30, that is, at the lower end position closer to the workpiece W. As shown in FIG. Therefore, since the amount of plasma irradiation acting on the work W can be increased, the modification action and etching action of the surface to be processed of the work W can be enhanced, and the processing rate and production efficiency can be further improved. .

Here, the inventors further studied the configuration of the protruding portion 38 in order to generate plasma capable of enhancing the above effect. As an example, Table 1 and FIG. 16 show the results of experiments conducted using samples (1) to (5) having different configurations of the protrusions 38 (see FIG. 15, but the processing pad 40 is not shown for the sake of simplification). shown in Table 1 shows the measurement results of the power [W] required to stably generate plasma. On the other hand, FIG. 16 shows the intensity of plasma generation at a predetermined distance (set to 2 mm, for example) from the lower surface of the plasma electrode 30, visualized using a plasma indicator (registered trademark) manufactured by Sakura Crepas Co., Ltd. Yes (dark areas indicate high (strong) intensity).

As shown in Table 1, the configurations (Samples (2) to (5)) having the projecting portion 38 generate plasma more stably than the configuration (Sample (1)) having no projecting portion 38. A result was obtained that required power can be reduced, that is, energy can be saved.

Moreover, as shown in FIGS. 16A to 16E, the protrusions 38 are provided on both of the two side surfaces 32a and 32b of the plasma electrode 30 with the same radial dimension (including substantially the same dimension) (Sample (4), (5)) can generate plasma with a higher (strong) intensity than the configuration (samples (2) and (3)) provided only on one side. Results were obtained that could be increased. In addition, the above effect can be obtained by setting the radial spacing dimension c between the two side surfaces 32a and 32b to be five times or more the radial spacing dimension a between the two protrusions 38A and 38B. It was also confirmed that it is suitable for obtaining reliably.

Furthermore, another modified example of the plasma electrode 30 will be described. Specifically, as shown in FIG. 17 (a cross-sectional view of a position corresponding to FIG. 3), two side surfaces 32a and 32b facing each other with the slit portion 36 therebetween are not provided with the projecting portion 38 (this If so, the axial region) is formed using an insulating material. According to this, it is possible to suppress the discharge to the area where the projecting portion 38 is not provided, so that the plasma can be generated more intensively between the two projecting portions 38A and 38B. Therefore, the amount of plasma irradiation acting on the workpiece W can be increased.

Ceramics, heat-resistant glass, quartz, resin and the like are used as examples of the insulating material. Here, examples of the resin include POM (polyacetal resin), PVC (polyvinyl chloride resin), ultra-high molecular weight polyethylene resin, phenol resin, etc. when the plasma irradiation time is set to be relatively short. It is preferably used. On the other hand, when the plasma irradiation time is set to a relatively short time, heat resistance is required. resin) and the like are preferably used. When selecting the material and setting the thickness in the radial direction, the dimensional stability against the processing conditions, chemical resistance, etc. are taken into consideration.

(Second embodiment)
Next, a work processing device 1 according to a second embodiment of the present invention will be described. Here, FIG. 10 is a front cross-sectional view (schematic diagram) showing an example of the work processing apparatus 1 according to this embodiment. 11 is a sectional view (schematic diagram) taken along line XI-XI in FIG.

The work processing apparatus 1 according to this embodiment has the same basic configuration as that of the first embodiment described above, but has differences particularly in the mechanism for rotating the holding plate 20 and the like. The present embodiment will be described below with a focus on the difference. It should be noted that the modifications shown in FIGS. 8 and 9 can be similarly applied to the present embodiment.

Specifically, in the present embodiment, the holding plate 20 is held (fixed) on the rotating disk 12 by aligning it with the central axis of the rotating disk 12 without using a carrier. there is That is, when the turntable 12 is rotated (in the direction of arrow A), the holding plate 20 is rotated (in the direction of arrow C). The processing head 14 is configured to rotate (in the direction of arrow B) as in the first embodiment.

Compared to the first embodiment described above, only one holding plate 20 is held on the rotary table 12. Therefore, although the number of workpieces W that can be processed at the same time is reduced, the size of the apparatus can be greatly reduced. It is possible to plan

On the other hand, as for the processing heads 14, a plurality of (for example, two) are arranged. However, the present invention is not limited to this configuration, and as a modification, a configuration (not shown) in which three or more processing heads 14 are arranged may be employed.

As another modified example, as shown in FIG. 12 (a cross-sectional view of a position corresponding to FIG. 11), one processing head 14 may be arranged with its axis aligned with the rotating disk 12. good. In the case of this configuration, the turntable 12 can be set to a low speed state or a stopped state when the processing head 14 is rotated to perform processing. In particular, when only workpieces W that can be processed while the rotary table 12 is in a stopped state are to be processed, a simple device configuration without a rotating mechanism can be used, thereby reducing the cost of the device.

As another modification, as shown in FIGS. 13 and 14 (both of which are cross-sectional views corresponding to FIG. 11), one machining head 14 is arranged eccentrically with respect to the rotating disk 12. It may be configured to be FIG. 13 shows an example in which a plurality of workpieces W having a smaller diameter than the radius of the holding plate 20 are held (attached) on the holding surface (upper surface) of the holding plate 20 and processed. On the other hand, FIG. 14 shows an example in which one work W having a diameter larger than the radius of the holding plate 20 is held (attached) on the holding surface (upper surface) of the holding plate 20 and processed. In any case, according to this configuration, it is possible to machine the entire surface of the work W with only one machining head 14 . Therefore, as compared with the case where a plurality of processing heads 14 are provided, the device configuration can be simplified, and the cost of the device can be reduced.

Other functions and effects are the same as those of the above-described first embodiment, so repeated descriptions will be omitted.

As described above, according to the present invention, even a workpiece formed using a difficult-to-process material can be processed while modifying and etching the surface to be processed, so that the processing rate is increased. becomes possible. In addition, plasma processing and processing can be performed at the same time, that is, in a continuous process without rearranging workpieces between mechanisms. It becomes possible.

In addition, the present invention is not limited to the embodiments described above, and various embodiments are conceivable. Specifically, the rotation mechanism of the holding plate is configured to be selected from only rotation, only revolution, rotation and revolution, or non-rotation. Either revolving or non-rotating can be selected, and there are as many configuration examples as the number of combinations thereof (except for a combination in which the holding plate is non-rotating and the processing head is non-rotating). These configuration examples can also provide the same kind of effects as described above.

Incidentally, the above-described first embodiment corresponds to the case where the rotation mechanism of the holding plate rotates and revolves, and the rotation mechanism of the processing head rotates. Further, the above-described second embodiment corresponds to the case where the rotation mechanism of the holding plate is configured to rotate, and the rotation mechanism of the processing head is configured to rotate. In particular, in the case of these embodiments, the effect of improving the processing rate and production efficiency is enhanced.

Regarding the work to be processed, a disk-shaped wafer has been described as an example, but it is not limited to this, and other flat plate-shaped (especially disk-shaped) workpieces can also be processed. can be applied as well.

1 Work processing device 12 Turntable 14 Processing head 20 Holding plate 22 Carrier 30 Plasma electrodes 32, 32A to 32H Split electrodes 34, 34A to 34D Additional electrode 36 Slit 38 Protrusion 40 Processing pad 40a Extension W Work

Claims (9)

A work processing device for processing a surface to be processed by bringing a processing head into sliding contact with a work held on an upper surface of a holding plate,
The processing head is rotatably provided and has a plasma electrode that generates plasma and irradiates the surface to be processed of the workpiece,
The plasma electrode is divided into a plurality of divided electrodes in the circumferential direction, and a slit portion provided between the adjacent divided electrodes is configured as a plasma generation space. A work processing device, comprising a processing pad. 2. The workpiece processing apparatus according to claim 1, wherein said plasma electrode is formed in a circular shape when viewed from the bottom, and is divided into two or more divided electrodes which are symmetrical with respect to an axial center point. 2. The plasma electrode has a projecting portion projecting in a direction to reduce the radial dimension of the slit portion at a lower end position of at least one of two side surfaces facing each other through the slit portion. Alternatively, the work processing apparatus according to claim 2. 4. The work processing apparatus according to claim 3, wherein the protrusions are formed in a shape that protrudes in the same radial dimension at lower end positions on both of the two side surfaces. 5. The work processing apparatus according to claim 4, wherein the radial interval between the two side surfaces is five times or more the radial interval between the two protrusions. . 6. A work processing apparatus according to claim 4, wherein said side surface is formed using an insulating material in a region where said projecting portion is not provided. The plasma electrode further has a plate-shaped or block-shaped additional electrode in the slit section, and in a plan view, the slit section becomes a space divided by the additional electrode, and each of the spaces is configured as a plasma generation space. 7. The work processing device according to any one of claims 1 to 6, characterized in that it is The machining head has an outer diameter and an arrangement that allow the slit portion to pass through and the machining pad to slide against the entire area of the machining surface of all the workpieces whose positions are relatively changed. 8. The work processing device according to any one of claims 1 to 7, wherein a plurality of the work pieces are provided. 9. The processing pad according to any one of claims 1 to 8, wherein the processing pad has an upwardly sloping extending portion extending outward by a predetermined length from the side surface of the plasma electrode. work processing equipment.

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