Plasma etching tool and plasma etching method

Abstract

To provide a plasma etching tool capable of controlling the amount of etching in a depth (thickness) direction at an arbitrary position.SOLUTION: A plasma etching tool 100 includes a mounting surface 110 on which an insulating workpiece material w is mounted. The plasma etching tool includes a base 120 formed of an insulating material, and a conductor pattern 130 which is disposed on a surface or an interior of the base 120 and is located at a portion where an etching depth of the insulating workpiece material w should be increased when the base 120 is viewed from a direction perpendicular to the mounting surface 110.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plasma etching tool and a plasma etching method. [Background technology]

[0002] Plasma etching is used as a surface processing method in the manufacture of electronic devices such as semiconductors.

[0003] In plasma etching, there is a problem that the distribution of plasma becomes non-uniform in the surface direction, which causes non-uniform etching speed in the depth (thickness) direction within the surface, resulting in reduced flatness. As a solution to this problem, Patent Document 1 discloses a method of attracting plasma uniformly by changing the impedance of the electrostatic chuck that fixes the workpiece material within the surface, thereby changing the generated DC bias.

[0004] In addition, in plasma etching, a resist is formed in a predetermined pattern on the surface of the workpiece, and the portions where the resist is not formed are selectively etched, but there is also a problem that the etching depth varies depending on the dimensions of the portions where the resist pattern is not formed. As a solution to this problem, Patent Document 2 discloses forming a deposition layer of a different thickness in the opening of the resist depending on its size. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2002-540616 [Patent Document 2] Patent Publication No. 2022-29847 Summary of the Invention [Problem to be solved by the invention]

[0006] The technique disclosed in Patent Document 1 requires that etching be performed in advance in an apparatus to be used to check the degree of non-uniformity in plasma distribution, and then an electrostatic chuck having an impedance distribution corresponding to the degree of non-uniformity is fabricated, which is time-consuming and labor-intensive.

[0007] Furthermore, the technique disclosed in Patent Document 2 requires repeated steps of forming a deposition layer, etching, and ashing to remove the remaining deposition layer, which is time-consuming and labor-intensive.

[0008] Furthermore, when forming a resist pattern as in the technology disclosed in Patent Document 2, various processes such as coating the surface of the workpiece with resist, exposure, and development are required. In this case, cleaning with a solvent is also required to remove the resist pattern after etching. Thus, plasma etching using a resist pattern has the problem of requiring time-consuming pre- and post-treatments.

[0009] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a plasma etching tool that can be easily manufactured and enables control of the amount of etching in the depth (thickness) direction at any position. [Means for solving the problem]

[0010] In the course of research to achieve the above-mentioned object, the inventors have found that, in a processing surface of a thin insulating workpiece, the etching rate in the depth direction is higher at a location where a conductive member is arranged at the bottom of the opposing surface than at other locations, and conversely, the etching rate in the depth direction is lower at a location where an insulating member is arranged at the bottom of the opposing surface or a location where a space is formed than at a location where a conductive member is arranged.The inventors have found that the above-mentioned object can be achieved by utilizing this phenomenon and performing etching by placing, on the surface opposing the processing surface of the insulating workpiece, a jig having a conductor pattern corresponding to the shape of the location to be deeply etched, or a jig having a dielectric pattern or a recess corresponding to the shape of the location to be suppressed from etching, and have completed the present invention.

[0011] That is, a first aspect of the present invention is a plasma etching jig having a mounting surface on which an insulating workpiece is placed, characterized in that the plasma etching jig comprises a base formed of an insulating material, and a conductor pattern disposed on the surface or inside of the base and positioned at a location where it is desired to increase the etching depth of the insulating workpiece when the base is viewed from a direction perpendicular to the mounting surface.

[0012] In addition, a second aspect of the present invention is a plasma etching jig having a mounting surface on which an insulating workpiece is placed, characterized in that the plasma etching jig comprises a base formed of an insulating material, and a dielectric pattern formed of a material having a relative dielectric constant different from that of the insulating material, which is placed on the base or embedded flush with the base, constituting at least a part of the mounting surface, and which is located at a position that makes the etching depth of the insulating workpiece different when the base is viewed from a direction perpendicular to the mounting surface.

[0013] A third aspect of the present invention is a plasma etching tool having a mounting surface on which an insulating workpiece is placed, the plasma etching tool being formed of an insulating material and characterized in that a recess pattern is arranged on the mounting surface at a position where it is desired to reduce the etching depth of the insulating workpiece when viewed from a direction perpendicular to the mounting surface.

[0014] Furthermore, a fourth aspect of the present invention is a plasma etching method including placing an insulating workpiece on a mounting surface of a plasma etching jig according to any one of the first to third aspects, and placing the jig in a chamber of a plasma etching apparatus, evacuating air from the chamber, introducing a process gas into the chamber after evacuation, supplying power to a plasma generating electrode placed in the chamber to convert the process gas into plasma, and etching a surface of the insulating workpiece with the generated plasma. Effect of the Invention

[0015] According to the present invention, it is possible to provide a plasma etching tool that can be easily manufactured and that allows the amount of etching in the depth (thickness) direction to be controlled at any position. [Brief description of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing an embodiment (first embodiment) of a plasma etching jig according to a first aspect of the present invention. [Diagram 2] 3 is a cross-sectional view showing an example of an arrangement of conductive members in the first embodiment. FIG. [Diagram 3] 3 is a cross-sectional view showing an example of an arrangement of conductive members in the first embodiment. FIG. [Figure 4] 3A to 3C are cross-sectional views showing the results of plasma etching using the plasma etching jig according to the first embodiment. [Diagram 5] FIG. 4 is a cross-sectional view showing a modified example of the first embodiment. [Figure 6] FIG. 4 is a cross-sectional view showing a modified example of the first embodiment. [Figure 7] 4 is a cross-sectional view showing an embodiment (second embodiment) of a plasma etching jig according to a second aspect of the present invention. FIG. [Figure 8] 11A to 11C are cross-sectional views showing the results of plasma etching using the plasma etching jig according to the second embodiment. [Figure 9] 11A to 11C are cross-sectional views showing the results of plasma etching using the plasma etching jig according to the second embodiment. [Figure 10] FIG. 11 is a cross-sectional view showing a modified example of the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view showing a modified example of the second embodiment. [Figure 12] FIG. 11 is a cross-sectional view showing an embodiment (third embodiment) of a plasma etching jig according to a third aspect of the present invention. [Figure 13] 11A to 11C are cross-sectional views showing the results of plasma etching using the plasma etching jig according to the third embodiment. [Figure 14] 11A to 11C are cross-sectional views showing the results of plasma etching using the plasma etching jig according to the third embodiment. [Figure 15] FIG. 11 is a cross-sectional view showing a modified example of the third embodiment. [Figure 16] FIG. 11 is a cross-sectional view showing a modified example of the third embodiment. [Figure 17] FIG. 11 is a cross-sectional view showing an example of the configuration of a plasma etching apparatus used in a plasma etching method according to a fourth aspect of the present invention. [Figure 18] 1 is a cross-sectional view showing a structure of a test jig 1 according to an experimental example 1. FIG. [Figure 19] FIG. 2 is a cross-sectional view showing the arrangement of an insulating workpiece (quartz plate) on a test jig 1 and the area that has been etched. [Figure 20] 20 is a graph showing the results of measuring the height distribution of the quartz plate after local plasma etching in the regions a to c in FIG. 19. [Figure 21] 1 is a cross-sectional view showing the structure of a test jig 2-1 according to an experimental example 2 and the arrangement of an insulating workpiece (quartz plate). [Figure 22] 10 is a cross-sectional view showing the structure of a test jig 2-2 according to an experimental example 2 and the arrangement of an insulating workpiece (quartz plate). [Diagram 23] 22 is a graph showing the results of measuring the height distribution of a quartz plate after local plasma etching in the region indicated by the arrow in FIG. 21. [Figure 24] 23 is a graph showing the results of measuring the height distribution of a quartz plate after local plasma etching in the region indicated by the arrow in FIG. 22. [Diagram 25] 10 is a cross-sectional view showing the structure of a test jig 3 according to an experimental example 3 and the arrangement of an insulating workpiece (quartz plate). FIG. [Figure 26] 13 is a graph showing the results of measuring the height distribution of a quartz plate in the vicinity of a region where local plasma etching was performed in Experimental Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Each aspect of the present invention will be described in detail below based on one embodiment, but the present invention is not limited to this embodiment.

[0018] One embodiment of the present invention includes each of the following aspects [1] to [8]. [1] A plasma etching tool having a mounting surface on which an insulating workpiece is placed, the plasma etching tool comprising: a base made of an insulating material; and a conductor pattern disposed on or inside the base and positioned at a location where it is desired to increase the etching depth of the insulating workpiece when the base is viewed from a direction perpendicular to the mounting surface. [2] The plasma etching jig according to [1], wherein the distance of the conductor pattern from the mounting surface varies depending on the position. [3] The plasma etching jig according to [1] or [2], wherein the conductor pattern is grounded. [4] The plasma etching jig according to [1] or [2] above, wherein the conductor pattern is made of a resin having a dispersed particulate conductive material. [5] A plasma etching tool having a mounting surface on which an insulating workpiece is placed, the plasma etching tool comprising: a base made of an insulating material; and a dielectric pattern formed of a material having a dielectric constant different from that of the insulating material, the dielectric pattern being placed on the base or embedded flush in the base to form at least a part of the mounting surface and located at a position that makes the etching depth of the insulating workpiece different when the base is viewed from a direction perpendicular to the mounting surface. [6] The plasma etching jig according to [5], wherein the dielectric pattern is made of a particulate dielectric material dispersed in a resin. [7] A plasma etching tool having a support surface on which an insulating workpiece is placed, the tool being formed of an insulating material and characterized in that a recess pattern is arranged on the support surface at a position that reduces the etching depth of the insulating workpiece when viewed from a direction perpendicular to the support surface. [8] A plasma etching method comprising: placing an insulating workpiece on a mounting surface of the plasma etching jig described in any one of [1] to [7] above, and placing the jig in a chamber of a plasma etching apparatus; exhausting air from the chamber; introducing a process gas into the chamber after exhaustion; supplying power to a plasma generating electrode placed in the chamber to generate plasma from the process gas; and etching a surface of the insulating workpiece with the generated plasma. [9] The plasma etching method according to [8] above, wherein the plasma generation is carried out in a plasma generating tube through which the process gas flows and in which the plasma generating electrode is disposed on the outer periphery.

[10] The plasma etching method according to [9], wherein the process gas in the chamber is converted into plasma while being sucked from the tip of the plasma generating tube.

[0019] [Plasma etching fixture] (First embodiment) A first embodiment of a plasma etching jig according to a first aspect of the present invention is shown in Fig. 1. The plasma etching jig 100 according to the first embodiment has a mounting surface 110 on which an insulating workpiece w is placed, and is characterized by comprising a base 120 made of an insulating material, and a conductor pattern 130 disposed on or inside the base 120 and positioned at a location where it is desired to increase the etching depth of the insulating workpiece w when the base 120 is viewed from a direction perpendicular to the mounting surface 110.

[0020] The placement surface 110 is a surface on which the insulating workpiece w is placed, and is in direct contact with the surface of the insulating workpiece w facing the surface to be processed. The placement surface 110 may be continuously formed of a base 120 as shown in Fig. 1, may be discontinuously formed of a conductor pattern 130 as shown in Fig. 2, or may be continuously formed of both the base 120 and the conductor pattern 130 as shown in Fig. 3.

[0021] The base 120 is made of an insulating material. The insulating material has a significantly weaker effect of drawing in plasma than a conductive material. In addition, the insulating material has the effect of significantly weakening the drawing in of plasma by the conductive material by being interposed between the conductive material and the plasma. Therefore, by forming the base from an insulating material, the effect on the etching rate of the conductive material located on the opposite side of the insulating workpiece material w with respect to the plasma etching jig 100 can be significantly reduced, and the etching rate of the insulating workpiece material w at the location where the conductor pattern 130 described later is not arranged when the base 120 is viewed from a direction perpendicular to the mounting surface 110 can be significantly reduced.

[0022] The material for forming the base 120 is not limited as long as it has electrical insulation and excellent shape stability. When the plasma etching tool 100 is used at room temperature, a resin material such as polyimide or silicone can be used. On the other hand, when the plasma etching tool 100 is used at high temperature, a ceramic material such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), sialon (Si3N4·Al2O3), or glass can be used.

[0023] The thickness of the substrate 120 is not particularly limited, but in order to obtain a sufficient chucking force when the plasma etching tool 100 and the insulating workpiece w are electrostatically chucked during plasma etching, the thickness of the substrate 120 is preferably 2000 μm or less, and more preferably 500 μm or less. On the other hand, in order to sufficiently reduce the influence of the conductive material located on the opposite side of the plasma etching tool 100 from the insulating workpiece w on the etching rate, the thickness of the substrate 120 is preferably 10 μm or more, and more preferably 30 μm or more.

[0024] A conductor pattern 130 is disposed on the base 120. The conductor pattern 130 is disposed at a position where the etching depth of the insulating workpiece w is to be increased when the base 120 is viewed from a direction perpendicular to the mounting surface 110. Since the conductor pattern 130 has a strong effect of attracting plasma, the etching speed of the insulating workpiece w increases at the position where the conductor pattern 130 is disposed, and the etching depth increases. By utilizing this phenomenon, a predetermined uneven pattern can be formed in the workpiece surface of the insulating workpiece w, as shown in FIG. 4.

[0025] The conductive pattern 130 may be disposed on the surface of the base 120 or may be disposed inside the base 120. When it is desired to increase the difference in etching depth depending on the position of the insulating workpiece material w, it is preferable to dispose the conductive pattern 130 so that the surface of the conductive pattern 130 is exposed on the surface of the base 120 as shown in FIG. 3, and it is more preferable to place the conductive pattern 130 on the surface of the base 120 as shown in FIG. 2. On the other hand, when it is not necessary to increase the difference in etching depth depending on the position of the insulating workpiece material w, it is preferable to dispose the conductive pattern 130 inside the base 120 as shown in FIG. 1. In this case, the greater the distance from the surface (mounting surface 110) of the base 120 to the conductive pattern 130, the smaller the difference in etching depth depending on the position of the insulating workpiece material w can be. The distance from the surface of the base 120 to the conductive pattern 130 is preferably 1500 μm or less, more preferably 500 μm or less, and even more preferably 50 μm or less, from the viewpoint of fully exerting the etching promotion effect of the conductive pattern 130.

[0026] The material of the conductor pattern 130 is not particularly limited as long as it includes a conductive material and is physically and chemically stable in the environment in which the plasma etching jig 100 is used. When the conductor pattern 130 is exposed on the surface of the base 120 or is disposed inside the base 120 without sintering, copper (Cu), stainless steel, etc. can be used. In this case, the conductor pattern 130 may be a resin having a particulate conductive material dispersed therein. When the conductor pattern 130 is a resin having a particulate conductive material dispersed therein, there is an advantage that the etching depth of the insulating workpiece w can be changed simply by changing the mixing ratio of the resin and the conductive material. On the other hand, when the base 120 is a ceramic material, for example, and the conductor pattern 130 is disposed inside the base 120 with sintering, tungsten (W), molybdenum (Mo), etc. can be used.

[0027] The conductive pattern 130 may be grounded. This allows the plasma to be sufficiently drawn in and a desired etching depth to be obtained even if the dimensions of the conductive pattern 130 are small when viewed in a direction perpendicular to the mounting surface 110.

[0028] (Modification of the first embodiment) As a modification of the first embodiment, as shown in Fig. 5, there is a plasma etching tool 100' in which a plurality of conductive patterns 130 are arranged inside a substrate 120 with the distance from the surface varying depending on the position. In a situation in which the plasma density increases toward the periphery of an insulating workpiece w and unevenness in thickness occurs, this plasma etching tool 100' acts to increase the plasma density near the center, thereby reducing unevenness in thickness. The same effect can also be obtained by a plasma etching tool 100'' in which conductive patterns 130 of different widths are arranged as shown in Fig. 6.

[0029] Second Embodiment An embodiment of the plasma etching jig according to the second aspect of the present invention is shown as the second embodiment in Fig. 7. The plasma etching jig 200 according to the second embodiment has a mounting surface 210 on which an insulating workpiece w is mounted, and is characterized by including a base 220 made of an insulating material, and a dielectric pattern 230 made of a material having a relative dielectric constant different from that of the insulating material, disposed on the base 220 or embedded flush with the base 220, constituting at least a part of the mounting surface 210, and positioned at a location that makes the etching depth of the insulating workpiece w different when the base 220 is viewed from a direction perpendicular to the mounting surface 210.

[0030] The placement surface 210 is a surface on which the insulating workpiece w is placed, and is in direct contact with a surface of the insulating workpiece w facing the surface to be processed. The placement surface 210 may be continuously formed of both a base 220 and a dielectric pattern 230, as shown in FIG.

[0031] The base 220 is made of an insulating material. As described above, the insulating material has the effect of significantly weakening the attraction of the plasma by the conductive material by being interposed between the conductive material and the plasma. Therefore, by forming the base 220 from an insulating material, even if a conductive material such as an electrostatic electrode in an electrostatic chuck is present on the opposite side of the insulating workpiece w with respect to the plasma etching jig 200, the effect of the conductive material on the etching rate can be significantly reduced.

[0032] The insulating material forming the base 220 is not limited as long as it has electrical insulation properties and excellent shape stability, and examples thereof include soda glass, sapphire, and polyurethane.

[0033] The thickness of the substrate 220 is not particularly limited, but in order to obtain a sufficient chucking force when the plasma etching tool 200 and the insulating workpiece w are electrostatically chucked during plasma etching, the thickness is preferably 2000 μm or less, and more preferably 500 μm or less. On the other hand, in order to sufficiently reduce the influence of the conductive material located on the opposite side of the plasma etching tool 200 from the insulating workpiece w on the etching rate, the thickness of the substrate 220 is preferably 10 μm or more, and more preferably 30 μm or more.

[0034] The dielectric pattern 230 is formed of a material having a relative dielectric constant different from that of the insulating material forming the base 220. The dielectric pattern 230 is disposed on the base 220 or embedded flush with the base 220 to form at least a part of the mounting surface 210. When the relative dielectric constant of the material forming the dielectric pattern 230 is smaller than that of the insulating material forming the base 220, the position of the dielectric pattern 230 in the mounting surface 210 is set to a position where the etching depth of the insulating workpiece material w is desired to be reduced when the base 220 is viewed from a direction perpendicular to the mounting surface 210. On the other hand, when the relative dielectric constant of the material forming the dielectric pattern 230 is larger than that of the insulating material forming the base 220, the dielectric pattern 230 is disposed at a position where the etching depth of the insulating workpiece material w is desired to be increased when the base 220 is viewed from a direction perpendicular to the mounting surface 210. Since a material with a small relative dielectric constant has a small amount of charge that moves when an AC electric field is applied (the polarization that occurs is small), the mounting surface 210 formed of a material with a small relative dielectric constant has a small effect of attracting plasma during plasma etching, and the etching rate of the insulating workpiece w placed thereon is low. For this reason, by forming the base 220 and the dielectric pattern 230 from materials with different relative dielectric constants, the etching depth can be made different depending on the position in the mounting surface. By utilizing this phenomenon, as shown in FIG. 8, a predetermined uneven pattern can be formed in the processing surface of the insulating workpiece w. Note that FIG. 8 and FIG. 9 described later show an example in which a jig is used in which the relative dielectric constant of the material forming the dielectric pattern 230 is smaller than that of the insulating material forming the base 220. From the viewpoint of forming a clear uneven pattern in the processing surface of the insulating workpiece w, the difference in the relative dielectric constant of the material forming the dielectric pattern 230 from the material forming the base 220 is preferably 1 or more, more preferably 5 or more, and even more preferably 10 or more.

[0035] The thickness of the dielectric pattern 230 is not particularly limited, but when the thickness is 5 μm or less, the thinner the pattern, the smaller the effect of reducing the etching rate. Therefore, as shown in Figure 9, the thickness of the dielectric pattern 230 can be changed at each position to form patterns of different depths within the workpiece surface of the insulating workpiece material w.

[0036] (Modification of the second embodiment) As a modification of the second embodiment, as shown in Fig. 10, there is a plasma etching jig 200' in which the entire surface of the mounting surface 210 is constituted by a dielectric pattern 230, and the thickness of the dielectric pattern 230 is changed depending on the position on the mounting surface 210 within a range of 500 µm or less. In a situation in which the plasma density increases toward the periphery of the insulating workpiece w and unevenness in thickness occurs, this plasma etching jig 200' acts to increase the plasma density near the center, thereby reducing unevenness in thickness. Moreover, the same effect can be obtained by a plasma etching jig 200'' in which dielectric patterns 230 of different widths are arranged, as shown in Fig. 11.

[0037] (Third embodiment) An embodiment of a plasma etching jig according to a third aspect of the present invention is shown as a third embodiment in Fig. 12. The plasma etching jig 300 according to the third embodiment has a mounting surface 310 on which an insulating workpiece w is placed, and is characterized in that it is made of an insulating material and has a recess pattern 330 arranged on the mounting surface 310 at a location that reduces the etching depth of the insulating workpiece w when viewed from a direction perpendicular to the mounting surface 310.

[0038] The placement surface 310 is a surface on which the insulating workpiece w is placed, and is in direct contact with the surface of the insulating workpiece w that faces the surface to be processed.

[0039] The plasma etching jig 300 is made of an insulating material. As described above, the insulating material has the effect of significantly weakening the attraction of plasma by the conductive material by being interposed between the conductive material and the plasma. Therefore, by forming the base from an insulating material, even if a conductive material such as an electrostatic electrode in an electrostatic chuck is present on the opposite side of the plasma etching jig 300 from the insulating workpiece w, the effect of the conductive material on the etching rate can be significantly reduced.

[0040] The insulating material to be used is not limited as long as it has electrical insulation and excellent shape stability. Examples include resin materials such as polyimide, silicone, and polyurethane, ceramic materials such as aluminum oxide (Al2O3), aluminum nitride (AlN), silicon nitride (Si3N4), and sialon (Si3N4·Al2O3), and glass. From the viewpoint of fully demonstrating the effect of reducing the influence on the etching rate of the conductive material located on the opposite side of the insulating workpiece material w with respect to the plasma etching jig 300 described above, and from the viewpoint of increasing the difference in etching rate with the location where the recess pattern 330 described later is arranged, materials with a relatively large relative dielectric constant such as soda glass, sapphire, and urethane are preferable. The relative dielectric constant of the insulating material is preferably 2 to 30, more preferably 3 to 25, and even more preferably 5 to 20.

[0041] The thickness of the plasma etching jig 300 is not particularly limited, but in the case where the plasma etching jig 300 and the insulating workpiece w are electrostatically chucked and held during plasma etching, the thickness is preferably 2000 μm or less, more preferably 500 μm or less, in order to obtain a sufficient chucking force. On the other hand, in order to sufficiently reduce the influence of the conductive material located on the opposite side of the plasma etching jig 300 from the insulating workpiece w on the etching rate, the thickness of the plasma etching jig 300 is preferably 10 μm or more, more preferably 30 μm or more.

[0042] The mounting surface 310 has a recess pattern 330 arranged at a position where the etching depth of the insulating workpiece w is to be reduced when viewed from a direction perpendicular to the mounting surface 310. The recess pattern 330 is an area where the insulating workpiece w mounted on the mounting surface 310 comes into contact with a low vacuum gas (atmospheric gas used during etching) having an extremely small relative dielectric constant, without being affected by the etching rate of the conductive material, even if a conductive material such as an electrostatic electrode in an electrostatic chuck is present on the opposite side of the insulating workpiece w with respect to the plasma etching jig 300, and thus the etching rate is significantly reduced. Therefore, the etching depth can be reduced more than at a position in direct contact with the mounting surface 310. By utilizing this phenomenon, a predetermined uneven pattern can be formed in the processing surface of the insulating workpiece w, as shown in FIG. 13.

[0043] The depth of the recess pattern 330 is not particularly limited. However, when the depth is 5 μm or less, the thinner the recess pattern, the smaller the effect of reducing the etching rate. Therefore, as shown in FIG. 14, the thickness of the recess pattern 330 can be changed at each position to form patterns of different depths within the workpiece surface of the insulating workpiece material w.

[0044] (Modification of the third embodiment) As a modification of the third embodiment, as shown in Fig. 15, there is a plasma etching jig 300' in which the depth of the recess pattern 330 formed on the mounting surface 310 is changed depending on the position on the mounting surface 310 within a range of 5 µm or more and 500 µm or less. In a situation in which the plasma density increases toward the periphery of the insulating workpiece material w and unevenness in thickness occurs, this plasma etching jig 300' acts to increase the plasma density near the center, thereby reducing unevenness in thickness. Moreover, the same effect can be obtained by a plasma etching jig 300'' in which recess patterns 330 of different widths are arranged as shown in Fig. 16.

[0045] Although the first to third embodiments and their modified examples have been described above, the present invention may be implemented by combining the respective embodiments. For example, when viewed from a direction perpendicular to the mounting surface, a plasma etching jig in which a dielectric pattern having a higher relative dielectric constant than the conductor pattern or the insulating material forming the base is disposed at a location where the etching depth of the insulating workpiece material is desired to be increased, and a dielectric pattern having a lower relative dielectric constant than the insulating material forming the base is disposed or a recess is formed at a location where the etching depth of the insulating workpiece material is desired to be decreased, is also within the scope of the present invention.

[0046] [Plasma etching method] (Fourth embodiment) An embodiment of the plasma etching method according to the fourth aspect of the present invention will be described as the fourth embodiment. FIG. 17 shows an example of the configuration of a plasma etching apparatus that can be used in the fourth embodiment. The plasma etching apparatus shown in FIG. 17 is a local plasma etching apparatus, but the plasma etching method according to the present invention is not limited to using this apparatus. FIG. 17 also shows a case where the plasma etching tool 100 according to the first embodiment is used as a representative embodiment of the present invention, but the usable plasma etching tool is not limited to this.

[0047] The plasma etching apparatus 500 includes a chamber 51 for accommodating an insulating workpiece w therein, a vacuum pump (not shown) for reducing the pressure inside the chamber 51, a gas supply means 52 for introducing a process gas into the chamber 51, a plasma generation electrode 53 for converting the process gas inside the chamber 51 into plasma, a high-frequency power source 54 for supplying power to the plasma generation electrode 53, a plasma generation tube 55 through which the process gas flows and on whose outer periphery the plasma generation electrode 53 is disposed, and an electrostatic chuck 56 disposed inside the chamber 51 for adsorbing and holding the insulating workpiece w and the plasma etching jig according to any one of the first to third embodiments on which the insulating workpiece w is placed.

[0048] The plasma etching method using the plasma etching apparatus 500 can be carried out by the following procedure. First, the plasma etching jig 100 is placed on the electrostatic chuck 56 arranged in the chamber 51 of the plasma etching apparatus 500, and the insulating workpiece w is placed thereon. Next, the electrostatic chuck 56 is operated to adsorb and hold the plasma etching jig 100 and the insulating workpiece w. Next, after exhausting the air in the chamber 51, the gas in the chamber 51 containing the process gas is sucked from the tip of the plasma generating tube 55 while supplying the process gas from the gas supply means 52. Next, power is supplied from the high frequency power source 54 to the plasma generating electrode 53 arranged around the plasma generating tube 55, and plasma is generated to etch the insulating workpiece w.

[0049] According to the plasma etching method of the fourth embodiment, etching can be performed in a predetermined pattern by simply placing the insulating workpiece w on the plasma etching jig of the first to third embodiments, which can be easily fabricated, and then etching the workpiece. EXAMPLES

[0050] Each embodiment of the present invention will be described in more detail below based on examples, but the present invention is not limited to these examples in any way.

[0051] [Experimental Example 1] In order to confirm the effect of the plasma etching jig according to the first embodiment, the following experiment was carried out.

[0052] (Preparation of test jig 1) First, a polyimide (Kapton) tape T1 having a length of 75 mm, a width of 20 mm, and a thickness of 35 μm was prepared, and a copper foil M1 having a length of 20 mm, a width of 15 mm, and a thickness of 10 μm was placed near the center of the surface of the tape. Next, a polyimide tape T2 having the same dimensions as the polyimide tape T1 was attached so as to overlap the polyimide tape T1, covering the copper foil M1. Next, a copper foil M2 having the same dimensions as the copper foil M1 was placed on the polyimide tape T2, at a distance of 5 mm or more from the copper foil M1 in the length direction. Next, a copper foil M3 having a length of 10 mm, a width of 15 mm, and a thickness of 10 μm was placed on the polyimide tape T2 so that one end in the length direction overlaps the copper foil M1. Next, a copper foil M4 having the same size as the copper foil M3 was placed on the polyimide tape T2 at a position on the opposite side of the copper foil M2 from the copper foil M3, at a distance of 10 mm or more in the length direction from the copper foil M3. Next, a polyimide tape T3 having the same dimensions as the polyimide tape T2 was attached so as to overlap the polyimide tape T2, covering the copper foils M2, M3 and M4 to obtain a test jig 1. The structure of the test jig 1 is shown in FIG. 18. In this test jig 1, the polyimide tapes T1 to T3 each correspond to a substrate, and the copper foils M1 to M4 each correspond to a conductor pattern.

[0053] (Plasma Etching Test) A quartz plate having a thickness of 300 μm as an insulating workpiece w was placed on the fabricated test jig 1 so as to overlap the polyimide tape T3 as shown in FIG. 19, and placed in a chamber of a suction plasma etching device equipped with a plasma generating tube having a diameter of 4 mm. After exhausting the chamber, carbon tetrafluoride (CF4) as an etching gas was supplied from the gas supply means at a flow rate of 90 SCCM, while the gas in the chamber containing the etching gas was sucked from the tip of the plasma generating tube. At this time, the pressure in the chamber was 800 Pa, and the back pressure of the plasma generating tube was 500 Pa. The distance between the tip of the plasma generating tube and the quartz plate was 0.2 mm, and power was supplied from an RF power source with an output of 50 W to the plasma generating electrode arranged around the plasma generating tube, generating plasma, and etching of the quartz plate was performed in each of the regions a to c in FIG. 19. The etching time was 600 seconds.

[0054] (Measurement of etching depth) The height distribution in the longitudinal direction (left-right direction in FIG. 19) of the test jig 1 was measured for each of the regions a to c of the etched quartz plate using a laser microscope (Keyence Corporation, VK-100X type). The results are shown in FIG.

[0055] From FIG. 20, it can be seen that deep and uniform etching was achieved in region a, where a conductor pattern was formed across the entire etching region directly below the mounting surface. It can also be seen that etching of different depths was achieved in region b, where a conductor pattern was arranged directly below the mounting surface for a portion of the etching region, and a conductor pattern was arranged away from the mounting surface for the remainder of the etching region. It can also be seen that etching of a shallower depth was achieved in region c, where a conductor pattern was arranged directly below the mounting surface for a portion of the etching region, and no conductor pattern was arranged for the remainder of the etching region. From these results, it was confirmed that etching of various patterns is possible depending on the arrangement of the conductor pattern in the plasma etching jig.

[0056] [Experimental Example 2] In order to confirm the effect of the plasma etching jig according to the second embodiment, the following experiment was carried out.

[0057] (Preparation of test jig 2-1) First, a quartz glass plate G1 (relative dielectric constant: 3.5 to 4.5) having a length of 10 mm, a width of 10 mm, and a thickness of 1 mm, and a sapphire (single crystal alumina) plate A1 of the same dimensions (surface perpendicular to the thickness direction: (11-20) surface (however, the "-" on the left side of the number is originally written above the number), relative dielectric constant: 11.5) were prepared. Next, a copper foil M having a length of 70 mm, a width of 50 mm, and a thickness of 300 μm was prepared, and the quartz glass plate G1 was placed on one side in the length direction, and the alumina single crystal plate A1 was placed on the other side, so that the ends in the width direction overlapped the copper foil M, respectively, to obtain a test jig 2-1 in which the boundary between the quartz glass plate G1 and the alumina single crystal plate A1 was located at the center in the length direction of the copper foil M. The structure of the test jig 2-1 is shown in FIG. 21.

[0058] (Preparation of test jig 2-2) Test jig 2-2 was fabricated in the same manner as test jig 2-1, except that the quartz glass plate G1 was replaced with a 0.5 mm thick sapphire (single crystal alumina) plate A2 (surface perpendicular to the thickness direction: (0001) plane, relative dielectric constant: 9.41), and the alumina single crystal plate A1 was replaced with a 0.5 mm thick single crystal strontium titanate plate S1 (surface perpendicular to the thickness direction: (001) plane, relative dielectric constant: 310). The structure of test jig 2-2 is shown in FIG. 22.

[0059] (Plasma Etching Test and Etching Depth Measurement) On the fabricated test jig 2-1, a quartz plate having a thickness of 300 μm was placed as an insulating workpiece material w so as to straddle the quartz glass plate G1 and the sapphire plate A1 as shown in FIG. 21, and plasma etching was performed in the same manner as in Experimental Example 1, and the etching depth was measured. On the fabricated test jig 2-2, a quartz plate having a thickness of 300 μm was placed as an insulating workpiece material w so as to straddle the sapphire plate A2 and the single crystal strontium titanate plate S1 as shown in FIG. 22, and plasma etching was performed in the same manner as in Experimental Example 1, and the etching depth was measured. Plasma etching and the measurement of the etching depth were performed in the areas indicated by the arrows in FIG. 21 and FIG. 22. The measurement results of the etching depth are shown in FIG. 23 and FIG. 24, respectively.

[0060] 23 and 24, it can be seen that the etching depth of the insulating workpiece w is greater on the mounting surface formed of a material having a large relative dielectric constant. From this result, it was confirmed that the etching depth can be locally increased by using a jig on which a dielectric pattern having a larger relative dielectric constant than the substrate is formed, and conversely, the etching depth can be locally decreased by using a jig on which a dielectric pattern having a smaller relative dielectric constant than the substrate is formed, and that etching of various patterns is possible by selecting the arrangement of the dielectric pattern and the relative dielectric constant.

[0061] [Experimental Example 3] In order to confirm the effect of the plasma etching jig according to the third embodiment, the following experiment was carried out.

[0062] (Preparation of test jig 3) A hole slide glass SG (T8-R004, manufactured by Toshin Riko Co., Ltd.) was prepared as the test jig 3. As shown in the cross-sectional view of Fig. 25, this was a glass plate with a thickness of 1.3 mm, in which a recess with a diameter of 14 mm to 15 mm and a maximum depth of 600 µm was formed in the center of the surface, and the depth of the recess increased from the vicinity of the circumference toward the center.

[0063] (Plasma Etching Test) As shown in Figure 25, a 300 μm-thick quartz plate as an insulating workpiece material w was placed on the test jig 3 so as to cover the recess, and a plasma etching test was performed near the boundary between the recess and the flat portion in the same manner as in Experimental Example 1.

[0064] (Measurement of etching depth) For the etched quartz plate, the height distribution in the length direction of the hole slide glass (the left-right direction in FIG. 25) was measured in the same manner as in Experimental Example 1. The results are shown in FIG.

[0065] It can be seen from Fig. 26 that shallower etching was achieved on the recessed pattern arranged on the mounting surface of the plasma etching jig made of an insulating material than on the mounting surface in contact with the insulating workpiece. This result confirmed that etching of various patterns is possible depending on the arrangement of the recessed pattern on the plasma etching jig. [Industrial Applicability]

[0066] According to the present invention, it is possible to provide a plasma etching tool that can be easily manufactured and enables processing with high dimensional accuracy in the depth (thickness) direction. Therefore, the present invention is useful in that it can improve the processing accuracy of a plasma etching device in a simple manner. In particular, the present invention is useful in that it can perform extremely high-precision processing in a local plasma etching device that generates plasma inside a plasma generating tube, particularly a suction plasma etching device. [Explanation of symbols]

[0067] 100, 200, 300, Plasma etching fixture 110, 210, 310 Placement surface 120, 220 base 130 Conductor Pattern 230 Dielectric Pattern 330 recess pattern 500 Plasma Etching Equipment 51 Chamber 52 Gas supply means 53 Plasma generating electrode 54 High frequency power supply 55 Plasma Generator Tube 56 Electrostatic Chuck w Insulating workpiece material

Claims

1. A plasma etching tool having a mounting surface on which an insulating workpiece is placed, A substrate formed of an insulating material, and A conductor pattern is disposed on the surface or inside of the substrate, and is located at a position where the etching depth of the insulating workpiece is desired to be increased when the substrate is viewed from a direction perpendicular to the mounting surface. A plasma etching tool comprising:

2. The plasma etching tool according to claim 1 , wherein the distance of the conductor pattern from the mounting surface varies depending on the position.

3. The plasma etching tool according to claim 1 , wherein the conductor pattern is grounded.

4. 2. The plasma etching tool according to claim 1, wherein the conductor pattern is made of a resin in which particulate conductive material is dispersed.

5. A plasma etching tool having a mounting surface on which an insulating workpiece is placed, A substrate formed of an insulating material, and The insulating material is made of a material having a different dielectric constant, The mounting surface is at least partly covered by the support member. and When the substrate is viewed from a direction perpendicular to the mounting surface, the insulating material is located at a position that makes the etching depth of the insulating material different. Dielectric Pattern A plasma etching tool comprising:

6. 6. The plasma etching tool according to claim 5, wherein the dielectric pattern is made of a resin in which particulate dielectric material is dispersed.

7. A plasma etching tool having a mounting surface on which an insulating workpiece is placed, formed of an insulating material, and A recess pattern is arranged on the mounting surface at a location where the etching depth of the insulating workpiece is to be reduced when viewed from a direction perpendicular to the mounting surface. A plasma etching tool comprising:

8. placing an insulating workpiece on the mounting surface of the plasma etching jig according to any one of claims 1 to 7 and disposing the jig in a chamber of a plasma etching apparatus; evacuating the air within the chamber; introducing a process gas into said chamber after evacuation; supplying power to a plasma generating electrode disposed in the chamber to generate plasma from the process gas; and Etching the surface of the insulating workpiece with the generated plasma.

2. A plasma etching method comprising:

9. 9. The plasma etching method according to claim 8, wherein the plasma generation is performed in a plasma generating tube inside which the process gas flows and on the outer periphery of which the plasma generating electrode is disposed.

10. 10. The plasma etching method according to claim 9, wherein the process gas in the chamber is converted into plasma while being sucked from a tip of the plasma generating tube.

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