JP2008112763A - Electrostatic chuck - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic chuck having strong adsorption force and preventing ununiformity in an adsorption plane. <P>SOLUTION: The electrostatic chuck comprises an electrode forming layer 8 consisting of an insulating layer 1 made of an insulating material, first electrodes 2 and second electrodes 3; and electrode protective layers 4, 5 for covering the surface of the electrode forming layer. The first electrodes each have a mesh pattern, the second electrodes each have a concave portion 31, and each concave portion 31 is disposed so as to face the mesh window 41 of the mesh electrode. The convex portion of the second electrode may be formed on a planar electrode, may be provided on, e.g., a cross point of electrodes having a mesh pattern or each convex electrode may be formed as a sole electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic chuck having a structure that has high durability against dielectric breakdown, exhibits a high adsorption force with respect to not only a conductive material but also an insulating material, and does not cause in-plane unevenness of adsorption.

  An electrostatic chuck exhibits an adsorption function in a vacuum and is easy to handle, and thus is indispensable in an IC manufacturing process. In particular, an electrode sheet for an electrostatic chuck composed of a plastic film and a copper foil can be manufactured at a low cost. Therefore, an electrostatic chuck device using the electrode sheet is widely used.

  The electrostatic chuck device used in the IC manufacturing process is generally a single-pole type. In this electrostatic chuck device, a semiconductor wafer is regarded as an electrode and a voltage is applied via a dielectric. As a result, a high adsorptive power is developed.

  In recent years, an attempt has been made to use an electrostatic chuck device to fix an insulating material such as plastic or glass. In this case, since it is difficult for the monopolar electrostatic chuck apparatus to exhibit an electrostatic attraction force, a bipolar electrostatic chuck incorporating two or more electrically insulated electrode surfaces is used. Such a bipolar electrostatic chuck has a structure in which two or more electrode surfaces electrically insulated on the same surface are disposed, and a potential difference of several thousand volts is applied between the two electrodes. Thus, the insulating material is electrostatically adsorbed (see, for example, Patent Documents 1 and 2).

  In this type of bipolar electrostatic chuck, insulation between electrodes may be ensured by filling an organic material such as an adhesive or a pressure-sensitive adhesive (hereinafter referred to as an adhesive). There is a problem that breakdown due to dielectric breakdown occurs in a short period of time due to problems at the time, foreign substances present in the adhesive, etc., foreign substances and bubbles mixed in the process of filling the adhesive and the like.

  In addition, when the electrostatic chuck is heated and used, the insulation resistance value of an insulating material such as an adhesive is remarkably lowered to increase the leakage current between the electrodes. When metals such as copper and silver are used as the material, the electrode material gradually elutes into the insulating material such as the adhesive layer due to ionization due to the effect of the electric field around the electrode, and ends. Has a problem of so-called electromigration that causes dielectric breakdown.

  In order to improve these points, there has been proposed an electrostatic chuck electrode sheet in which a first electrode layer is provided on one surface of an insulating layer and a second electrode layer is provided on the other surface (see Patent Document 3). . The electrode sheet specifically disclosed in this patent document is a comb-shaped electrode in which the first electrode layer is patterned, and the second electrode layer is provided on the entire surface of the insulating layer and has no electrode pattern. These are so-called solid electrodes. In the electrode sheet provided with such a comb-shaped electrode, the wiring between the portion close to the power source of the comb-shaped electrode (source portion) and the portion far from the power source (terminal portion) is a thin and long conductive portion. Yes. In the electrode having such a structure, a potential difference between the source portion and the end portion of the electrode is generated, resulting in a nonuniform voltage on the same electrode surface. This problem becomes more prominent as the electrode pattern becomes finer and the total length of adjacent electrodes in a unit area becomes longer. That is, as the wiring between the source portion and the end portion of the electrode becomes “thin” and “long”, the influence of the slight internal resistance of the electrode made of a conductive material such as metal becomes more conspicuous, and the potential difference between the source portion and the end portion tends to occur. Become. Therefore, the electrostatic chuck device using such an electrode sheet has a problem that non-uniformity of electric charge occurs in the electrostatic adsorption surface, and the member to be adsorbed (plastic, glass, etc.) cannot be held with a uniform force. In other words, the attracted member is distorted to generate internal stress, or in the worst case, the attracted member is dropped due to partial adsorption failure.

  Furthermore, in the wiring in which the portion between the power supply portion (source flow portion) near the power source and the portion far from the power supply (end portion) of the electrode sheet provided with such a comb-shaped electrode is a thin and long conductive portion, Transmission may be delayed. The delay of the electrical signal is not only worsening the responsiveness of the chucking / removing of the electrostatic chuck, but also hinders when it is desired to sucking / removing at a timely timing. Furthermore, since it takes time until the electric field at the adsorption interface becomes steady after the voltage is applied, it is difficult to instantaneously obtain a stable adsorption force. When the voltage application is stopped, it takes time for the charge at the end portion to escape, so that it tends to remain as a residual charge, the electrostatic attraction force tends to remain, and it is easy to prevent the instantaneous separation. This problem becomes more prominent as the electrode pattern becomes finer and the total extension of adjacent electrodes in a unit area becomes longer. That is, as the wiring between the source and end portions of the electrode becomes “thin” and “long”, it takes longer time for an electrical signal transmitted at a constant speed to reach the end portion of the electrode. A time difference is likely to occur in the potential change. Therefore, the electrostatic chuck device using such an electrode sheet has a slow adsorption / detachment operation, and when incorporated in the manufacturing process, there is a possibility that the interlocking of the preceding and subsequent processes may be hindered.

In addition, in the electrostatic chuck in which the first electrode layer is provided on one surface of the insulating layer and the second electrode layer is provided on the other surface, manufacturing defects such as etching defects, deformation due to foreign object biting, etc. In rare cases, a part of the first electrode layer is disconnected due to a trouble during use.
When the first electrode layer is a comb-shaped electrode, it is impossible to apply a voltage to the electrode on the terminal side of the disconnected portion, and thus there is a possibility that the electrostatic adsorption force as designed cannot be expressed. .
If the area of such a portion where voltage cannot be applied is large, it cannot be used as an electrostatic chuck. In the unlikely event that a wire breaks due to a trouble during use, the processed semi-finished product may be dropped and destroyed.

Moreover, in the conventional electrostatic chuck, many convex shapes may be formed on the surface of the electrostatic chuck in order to control the temperature of the electrostatic chucking surface (see, for example, Patent Document 4). At this time, since the object to be adsorbed is separated from the electrode by the height of the convex portion, a device such as applying a higher voltage than that in the case where there is no convex portion is required to obtain an electrostatic attraction force.
Japanese Patent Laid-Open No. 11-54602 JP 2000-211961 A JP-A-2005-64105 JP 2006-32461 A

  The present invention has been made for the purpose of solving the above-mentioned problems in the conventionally proposed electrode sheet for electrostatic chucks having a two-layer electrode structure. Accordingly, an object of the present invention is to provide an electrostatic chuck having a structure in which in-plane non-uniformity of adsorption does not occur and good durability and stable adsorption force are expressed. It is another object of the present invention to provide an electrostatic chuck having a structure capable of expressing a high attracting force even when an uneven shape is formed on the attracting surface.

  That is, the electrostatic chuck according to the first aspect of the present invention covers an electrode constituent layer composed of an insulating layer made of an insulating material, a first electrode, and a second electrode, and a surface of the electrode constituent layer. The first electrode is a mesh electrode having a mesh pattern, the second electrode is a three-dimensional electrode having a large number of embossed projections, and the second electrode The electrode is arranged with respect to the first electrode through the insulating layer so that the convex portion faces the first electrode side, and further at the position of the mesh window of the mesh pattern of the first electrode. It is characterized by a structure in which the convex portions are arranged.

  The electrostatic chuck of the second aspect of the present invention covers an insulating layer made of an insulating material, an electrode component layer composed of a first electrode and a second electrode, and a surface of the electrode component layer. And the first electrode is a mesh electrode having a mesh pattern, and the second electrode has a mesh window position of the mesh pattern of the first electrode having a convex shape. A three-dimensional mesh electrode configured by a three-dimensional mesh pattern having an intersection at the position of the mesh window, and the second electrode is disposed with respect to the first electrode via the insulating layer and is an electrode A structure in which the convex portion of the second three-dimensional mesh pattern is arranged so as to face the first electrode side at the position of the mesh window of the first electrode when seen through from the vertical direction of the constituent layer. .

  In the electrostatic chuck according to the first aspect of the present invention, since the first electrode has an electrode pattern made of a mesh electrode, not only the end portion far from the power source is eliminated, but also the thin and long wiring is eliminated. Therefore, when a voltage is applied so that a potential difference is generated between the electrode pair composed of the first electrode and the second electrode, the potential in the electrode constituent layer surface becomes uniform, and the charge in the electrostatic chuck attracting surface The effect is that the distribution is uniform. That is, the voltage drop at the end of the electrode is prevented, the in-plane electric field distribution becomes uniform, and the member to be adsorbed (plastic, glass, etc.) can be held with a uniform force. Furthermore, the delay of the electrostatic adsorption response at the electrode end due to the charge transfer being delayed toward the end is prevented. Furthermore, even if a part of the first electrode layer is disconnected due to a manufacturing failure such as defective etching or a trouble during use such as deformation due to foreign matter biting, it is a mesh electrode. A voltage is also applied to the electrode portion ahead of the disconnection portion. Therefore, it is possible to prevent the internal stress of the member to be attracted from being generated and to prevent the attracting member from dropping due to partial suction failure. In addition, since a highly insulating insulating layer is interposed between both electrodes, the electromigration is not affected even if there is an abnormality in the patterned electrode or if foreign matter or bubbles are mixed. Can be used stably for a long time. Further, the second electrode is a three-dimensional electrode having a number of embossed convex portions, and the convex portion of the second electrode is connected to the first electrode via the insulating layer with respect to the first electrode. When the voltage is applied so that a potential difference is generated between the two electrodes because the convex portion is arranged at the position of the mesh window of the mesh pattern of the first electrode. Since an electric field is easily formed between the mesh electrode as the first electrode and the convex portion of the second electrode disposed at a height close to the mesh electrode, the second electrode without the convex portion as in the prior art. As compared with the case of this electrode, a stronger electric field is generated on the side of the object to be adsorbed, thereby producing an effect that the electrostatic attraction force can be strongly expressed.

  Furthermore, in the electrostatic chuck according to the second aspect of the present invention, an insulating layer made of an insulating material, an electrode constituent layer composed of the first electrode and the second electrode, and a surface of the electrode constituent layer are provided. The electrode protective layer is made of an insulating material to be coated, and the first electrode is a mesh electrode having a mesh pattern like the electrostatic chuck of the first aspect of the present invention, and the second electrode is The mesh electrode position of the mesh pattern of the first electrode is a three-dimensional mesh electrode having a convex shape and is roughly constituted by a mesh pattern having an intersection at the mesh window position, and the second electrode is the first electrode. When the electrode is disposed through the insulating layer and seen through from the vertical direction of the electrode constituent layer, the convex portion of the second three-dimensional mesh pattern is located at the position of the mesh window of the first electrode. Is roughly arranged to face the electrode side of Therefore, when a voltage is applied so as to generate a potential difference between the two electrodes, the mesh electrode as the first electrode and the convex portion of the mesh electrode of the second electrode disposed at a height close to the mesh electrode An electric field is easily formed between the two. Thereby, the electrostatic chuck of the second aspect has an effect that a strong electric field similar to or higher than that of the electrostatic chuck of the first aspect is generated on the attracted member side, and the electrostatic attractive force can be strongly expressed. Produce.

  In addition, in the electrostatic chuck according to claim 6 of the present invention, in the electrode protective layer on the side serving as the electrostatic chucking surface of the electrostatic chuck of the first or second aspect, Since a convex portion is formed on the surface in accordance with the position of the convex portion, when a voltage is applied so that a potential difference is generated between the two electrodes, the mesh electrode as the first electrode and a high voltage adjacent to this are used. An electric field is easily formed between the second electrode and the convex portion of the second electrode, and the height of the convex portion is attracted from the electrode as compared with a conventional electrostatic chuck having a convex portion on the surface. The problem that the body is separated is eliminated, a strong electric field is generated on the side of the object to be adsorbed, and an effect that the electrostatic attraction force can be strongly expressed is produced.

  As described above, the electrostatic chuck of the present invention has high durability against dielectric breakdown, does not cause in-plane adsorption non-uniformity, and exhibits high adsorption force not only for conductive materials but also for insulating materials. Can do. In addition, an electrostatic chuck having a structure capable of expressing a high attracting force even when an uneven shape is formed on the attracting surface can be provided. For this reason, the electrostatic chuck of the present invention has a very high utility value especially for use in attracting and fixing a plate-shaped object to be adsorbed made of an insulating material such as glass or plastic.

The present invention will be described below with reference to the drawings.
FIG. 1 is a partial schematic cross-sectional view of an example of the electrostatic chuck according to the first aspect of the present invention, and FIG. 2 is a plan view of an electrode constituent layer of the electrostatic chuck shown in FIG. 1A is a cross-sectional view taken along line AA ′ in FIG. 2, and FIG. 1B is a cross-sectional view taken along line BB ′ in FIG.
As shown in FIGS. 1 and 2, the electrostatic chuck according to the first aspect of the present invention includes an electrode constituent layer 8 and electrode protective layers 4 and 5 covering both sides thereof. , An insulating layer 1 made of an insulating material, a first electrode 2, and a second electrode 3. The first electrode 2 is a mesh electrode having a mesh pattern as shown in FIG. 2, while the second electrode 3 has a number of embossed protrusions 31 as shown in FIG. It is a three-dimensional electrode, and the second electrode 3 is arranged so that the embossed convex portion 31 faces the first electrode 2 side with respect to the first electrode 2 with the insulating layer 1 interposed therebetween. The convex portion 31 is arranged at the position of the mesh window 41 of the mesh pattern of one electrode 2. FIG.12 (b) is a perspective view of one place of the embossed convex part 31 in Fig.11 (a).
The electrode protective layers 4 and 5 and the insulating layer 1 may be made of a single insulating material, or may be made of a plurality of different materials. Furthermore, the electrode protective layers 4 and 5 and the insulating layer 1 can all be made of the same material. In this case, the electrode protective layers 4 and 5 and the insulating layer 1 shown in FIG. Needless to say, it becomes a substance.
The second electrostatic chuck of the present invention is different from the second electrostatic chuck except that a convex portion is provided on the mesh pattern electrode, for example, at the intersection of the mesh pattern as shown in FIG. The configuration of is the same.

  3 to 7 are partial schematic cross-sectional views of other examples of the electrostatic chuck of the present invention. 3 and 6, the height of the top surface of the second electrode 3 is lower than the height of the top surface of the first electrode 2, that is, the height of the convex portion of the second electrode. The dimension is shorter than the thickness dimension of the insulating layer. In the electrostatic chucks of FIGS. 4 and 5, the top surface of the second electrode 3 is flush with the top surface of the first electrode 2. In the electrostatic chuck of FIG. 7, the height of the top surface of the second electrode 3 is higher than the height of the top surface of the first electrode 2, that is, the convex portion of the second electrode is the first. It is provided through the mesh window of the electrode. Further, in the electrostatic chuck of FIG. 4, concave portions are formed on the opposing surfaces of the embossed convex portions 31 of the second electrode 3 on the electrode side surface of the electrode protective layer 4. On the other hand, in the electrostatic chucks of FIGS. 5 to 7, each embossed convex portion 31 of the second electrode 3 is disposed so as to face the first electrode 2 side through the insulating layer 1. An embossed convex portion 31 is arranged at the position of the mesh window of the mesh pattern of the electrode 2. And the convex part 42 is formed in the adsorption | suction surface of the electrode protective layer 4 which touches a 1st electrode in the position of each embossed convex part 31 of a 2nd electrode. The concave portion formed between the convex portions 42 can be a flow path for a fluid such as nitrogen gas used for the purpose of adjusting the temperature of the adsorbent.

  FIG. 8 is a schematic cross-sectional view of another example of the electrostatic chuck of the present invention. The electrostatic chuck shown in FIG. 8 is an electrostatic chuck in the case where the electrostatic chuck 10 having the structure shown in FIG. The electrostatic chuck 10 is configured such that the electrode protective layer 4 in contact with the first electrode is stuck on the base 7 with an adhesive layer 6 so as to be an adsorption surface. FIG. 9 is a plan view of an electrode constituent layer of the electrostatic chuck according to the second aspect of the present invention. In the electrode constituent layer of the electrostatic chuck according to the second aspect of the present invention shown in FIG. 9, the second electrode 3 having a mesh pattern having a convex shape at the intersection is shown on the first electrode 2 which is a mesh electrode. It is configured to be laminated via an insulating layer made of an insulating material that is not formed.

  Next, each layer constituting the electrostatic chuck of the present invention will be described. For the lamination and molding of the electrode protective layer, the first electrode, the second electrode, and the insulating layer constituting the electrostatic chuck, various materials are fused. By appropriate methods, such as a method of bonding by adhesion, a method of bonding various materials without using an adhesive, a method of directly forming each layer by vapor deposition, sputtering, plating, thermal spraying, aerosol deposition, injection molding, press molding, etc. What is necessary is just to implement and it is not limited at all.

As the insulating material constituting the insulating layer, there are no ceramic materials such as silicon carbide, silicon nitride, alumina, zirconia, organic polymer materials such as polyimide, inorganic polymer materials ceramic such as silicone compounds, plastic film, etc. It is not limited. When using a plastic film as an insulating material for forming an insulating layer, films of polyimide, polyethylene terephthalate, polyethylene naphthalate, aramid, polyolefin, polyethersulfone, polyetherketone, polytetrafluoroethylene, polyphenylene sulfide, etc. A plastic film is preferred. In particular, a highly heat-resistant polyimide film can be preferably used because the leakage current does not increase even at high temperatures and the risk of electromigration is extremely small.
The insulating layer may be a laminate of two or more of the above films.

  The thickness of the insulating layer is not limited in any way, but the range of 1 to 300 μm is preferable, and the range of 12.5 to 300 μm is preferable in consideration of availability and ease of handling. . If the thickness of the insulating layer is less than 1 μm, the insulation is insufficient, and dielectric breakdown occurs at a voltage with a potential difference of several thousand volts. On the other hand, when the thickness is larger than 300 μm, the adsorptive power decreases, which is not preferable. The insulating layer may be formed by, for example, dissolving the insulating material in a solvent and directly coating it on the second electrode layer, or may be formed directly on the second electrode layer by other methods. . The insulating layer may be formed by laminating a film made of the insulating material on the second electrode layer. Moreover, in the case of a film, you may laminate | stack two or more.

  The first electrode is a mesh electrode, but the mesh shape, thickness, and hole size can be set as appropriate. For example, the mesh line width of the mesh pattern of the first electrode is preferably 0.01 mm or more and 5 mm or less, and the area of the mesh window is preferably 0.5 mm 2 or more. Moreover, it is preferable that the distance between the part except the convex part of a 1st electrode and a 2nd electrode is 0.01 mm or more. Further, for example, the mesh as shown in FIG. 2 may be a square mesh electrode, the mesh as shown in FIG. 10 may be a circular mesh electrode, and the mesh as shown in FIG. 11 may be a hexagonal mesh electrode. . The first electrode can be formed by an appropriate method such as vapor deposition, adhesion, and application of various metal foils, conductive films, conductive pastes, and the like. The material and thickness are not limited at all, but the film thickness is preferably as long as it is within a range that can ensure conductivity over a long period of time, and a metal foil having a thickness of 150 μm or less, particularly 35 μm or less, for example, Copper foil is preferred. A thickness greater than 150 μm is not preferable because it is difficult to produce a pattern.

On the other hand, in the case of the electrostatic chuck of the first aspect, the second electrode has a large number of embossed convex portions 31 as shown in FIGS. Further, in the case of the electrostatic chuck of the second aspect, it is a three-dimensional mesh electrode having a convex shape 62 as shown in FIG. What is necessary is just to set suitably the convex-shaped part of these 2nd electrodes in the state insulated from the 1st electrode in each mesh window of the mesh pattern of the 1st electrode. In the second electrode of FIG. 12 which is an example of the second electrode in the electrostatic chuck of the first aspect, a plurality of island electrodes 33 having embossed convex portions 31 are electrically connected by the thin line portions 32. ing. Further, the second electrode of FIG. 13A, which is another example of the second electrode in the electrostatic chuck of the first aspect, is composed of a flat plate 51 and has a large number of embossed convex portions 52. . 12 (b) and 13 (b) are perspective views of one portion of the embossed convex portion 52 in FIG. 12 (a) or 13 (a). FIG. 14A is an example of the second electrode in the electrostatic chuck of the second embodiment, which is made of a mesh electrode and has a convex shape 62 between the electrode wires 61 constituting the mesh. . FIG.14 (b) is a perspective view of one place of the convex shape 62 in Fig.14 (a).
The second electrode can be formed of various metal foils and conductive films. The material and the thickness are not limited at all, but the film thickness is not limited as long as it can be embossed and is generally set in the range of 0.1 to 100 μm.
Moreover, the electrode protective layer 5 which shape | molded the convex part previously can also be utilized as a method of forming an embossed convex part. In this case, the electrode protective layer 5 can be a ceramic molded product, a plastic molded product, a metal cast product whose surface is insulated with an oxide film, etc., and various metal foils or conductive films are appropriately attached to these surfaces, or An electrode pattern may be formed by applying conductive paste, metalizing by vapor deposition, or the like, and etching or blasting as necessary. When the embossed convex portion is formed of metal, the metal itself can be used as the second electrode. In this case, however, it is necessary to coat the electrode with an electrode protective layer made of another insulating material.

The electrode constituent layer can be formed by various methods. For example, various metal foils, conductive films, conductive pastes, etc. were used on one surface of an insulating plastic film as an insulating layer, and a mesh-like electrode pattern was formed by vapor deposition, sticking, coating, etching, etc. A hole is made in the insulating plastic film in the mesh portion of the mesh electrode. On the other hand, various metal foils and conductive films are embossed to produce a second electrode, which can be attached to the other surface of the insulating plastic film. An electrode configuration layer for the chuck is formed. The electrode constituent layer for the electrostatic chuck of the second aspect is a portion of the second electrode on the surface opposite to the surface on which the first electrode is present of the electrode constituent layer manufactured as described above. Can be formed by appropriately removing the film by etching or the like.
In addition, the formation method of the electrode constituent layer is not limited at all, and various methods can be used. For example, a single-sided conductive plastic film sheet is prepared by pasting various metal foils or conductive films on one side of an insulating plastic film, which is an insulating layer, or applying a conductive paste or metalizing by vapor deposition. The first electrode is formed by forming a mesh pattern on the conductive side surface of the single-sided conductive sheet by etching or blasting. The second electrode is formed by creating another single-sided conductive sheet by the above-described method and embossing it by press working or the like. Thereafter, the sheet of the first electrode and the sheet of the second electrode are fused or bonded so that the embossed convex portion of the second electrode sheet is located in the mesh window of the electrode pattern of the first electrode sheet. If it overlaps and fixes by filling, bonding, etc., the electrode structure layer for the electrostatic chuck of a 1st aspect will be formed. Further, the electrode constituent layer for the electrostatic chuck of the second aspect is formed on the conductive side surface of the single-sided conductive sheet for the second electrode sheet when the electrode constituent layer is formed as described above. The second electrode pattern may be formed by etching or blasting.

  In order to ensure the insulation with respect to a to-be-adsorbed object and a base material, both surfaces of the said electrode structure layer are coat | covered with an electrode protective layer. Moreover, in order to prevent discharge from occurring, the edge of the electrode constituent layer needs to be in a state of being sealed with an electrode protective layer so that the electrode is not exposed to the outside.

  As a suitable material for the electrode protective layer, the same insulating materials used for the insulation between the first electrode and the second electrode can be used, but various inorganic materials including insulating alumina can be used. Also, polymer materials such as epoxy resin compositions can be listed.

  The film thickness of the electrode protective layer on the adsorption surface provided on the electrode constituent layer is set in the range of 1 to 300 μm. If the distance from the object to be adsorbed to the electrode constituent layer is smaller than 1 μm, the mechanical strength is insufficient, so that there is no durability. Although it is more desirable to set in the range of 25 to 150 μm, in actual use, it may be determined as appropriate depending on the desired function of the electrostatic chuck device and the characteristics of the material used. Moreover, it is preferable that an electrode protective layer consists of a polyimide film with a thickness of 12.5-300 micrometers. In addition, the film thickness of the electrode protective layer on the substrate side may be set as appropriate as long as it can ensure insulation between the substrate and the substrate. Moreover, although the height of the convex part 42 of an electrode protective layer can be set freely, about 0-2 mm is preferable in general, and if it is further 0-0.7 mm, it is more preferable. If the electrostatic attraction surface is too far from the first electrode, the electric field strength at the electrostatic attraction surface becomes weak and it is difficult to obtain a sufficient electrostatic attraction strength.

  Note that the electrode protective layer can be either a single-layer structure or a laminated structure of a plurality of materials. In the case of a laminated structure, a conductive material may be included as long as insulation is ensured.

  The electrostatic chuck of the present invention may adhere a sheet comprising the above electrode constituent layer and electrode protective layer on a substrate. In that case, it sticks so that the electrode protective layer of the side which touches the 1st electrode may become an adsorption surface. The substrate is not particularly limited, and for example, a metal substrate such as an aluminum substrate can be used.

  In the present invention, the insulating layer, the electrode, the electrode constituent layer, and the substrate may be laminated by an appropriate method, for example, it may be attached via an adhesive layer. As the adhesive constituting the adhesive layer, a non-conductive adhesive is preferable, but in order to ensure high insulation reliability, epoxy resin, phenol resin, diallyl phthalate resin, thermoplastic polyimide resin, maleimide resin, etc. An adhesive composed of: These resins may be used alone or in combination of two or more. Further, various elastomers such as NBR may be blended in order to impart flexibility, and various inorganic fillers including metal powder and alumina may be dispersed in order to improve thermal conductivity. It is also effective to add a coupling agent in order to improve the adhesive properties. The adhesive may be in the form of liquid or solid. In addition, since it does not require high insulation unless it is a part in contact with the electrode constituent layer, there is no limitation in selecting an adhesive or the like, and a conductive adhesive or the like may be used in some cases. I do not care.

  The thickness of the adhesive layer is preferably thinner as long as the interlayer adhesion can be secured. Specifically, it is 100 μm or less, more preferably 1 to 50 μm.

There are no restrictions on the method of laminating with adhesive, but in order to ensure ease of handling and thickness accuracy after lamination, a solid adhesive is applied to the peelable film at a predetermined thickness at room temperature. It is desirable to transfer and use a so-called dry film.
Moreover, you may use the plastic film with an adhesive agent by which the normal temperature solid adhesive agent was apply | coated to the single side | surface or both surfaces beforehand. Furthermore, for example, a net electrode may be provided on the polyimide film without using an adhesive or the like by using a structure in which a silver foil is directly laminated on one side of the polyimide film.

When a voltage is applied so that a potential difference is generated between the first electrode and the second electrode of the electrostatic chuck of the present invention, the object to be adsorbed on the electrode protective layer on the side where the first electrode and the second electrode exist Will be adsorbed. As the voltage application method, any method can be applied as long as a potential difference can be generated between the first electrode and the second electrode. That is, a method of applying voltages of different polarities between the first electrode and the second electrode, a method of grounding the first electrode (ground electrode), and applying a + or-voltage to the second electrode Any method of grounding the second electrode and applying a + or-voltage to the first electrode may be used. However, it is most preferable to ground the first electrode and apply a DC voltage to the second electrode. If these methods are adopted, it is possible to prevent the occurrence of dielectric breakdown even when foreign matter is present between the object to be adsorbed and the adsorption surface during use, or when flaws occur on the adsorption surface.
Hereinafter, the present invention will be described with reference to more specific examples, but the present invention is not limited thereto.

  One side of a polyimide film (trade name: Kapton 200H, manufactured by Toray DuPont Co., Ltd., 50 μm thick) with a 20 μm thick adhesive film, 12 μm thick copper foil (Mitsui Metal Mining Co., Ltd., trade name: TQ-VLP) was laminated. Subsequently, by etching, a mesh electrode (shape shown in FIG. 2) having an area of 90 × 90 mm composed of a mesh portion (conductive portion) having a width of 0.8 mm and a mesh portion (insulating portion) having a size of 5 mm × 5 mm is first. Formed as an electrode. Next, an adhesive film similar to the above was stuck on the other surface of the polyimide film, and then a hole having a size of 4 mm × 4 mm was formed in each mesh portion of the mesh electrode by sandblasting. On the other hand, embossing is performed on a copper foil having a thickness of 12 μm to form a second electrode having an uneven shape that engages with the hole, and the formed second electrode is formed on the back surface of the polyimide film. Through the adhesive film similar to the above, it was stuck so that the convex part of the second electrode was located in the hole part of the polyimide film, and an electrode constituent layer was produced.

  A polyimide film (Kapton 200H) was laminated on both surfaces of the electrode constituent layer produced as described above via an adhesive film having a thickness of 20 μm, respectively, to obtain an electrostatic chuck of the present invention.

  Next, this electrostatic chuck was cut into a predetermined size and then adhered to a 5 × 100 × 100 mm aluminum substrate using an adhesive film having a thickness of 20 μm.

  In addition, the adhesive film used for said sticking is as follows. A composition having a weight ratio of 1: 1 between a resole phenol resin (trade name: Shonor CKM-908A, manufactured by Showa Polymer Co., Ltd.) and NBR (trade name: Nipol 1001, manufactured by Nippon Zeon Co., Ltd.) is used as an adhesive. This composition was dissolved in methyl ethyl ketone to prepare an adhesive paint having a solid content of 30% by weight, applied to one side of a releasable polyethylene terephthalate film (thickness 38 μm), and then heated and dried at 150 ° C. for 3 minutes. Thus, an adhesive film having a thickness of 20 μm is prepared.

  Moreover, lamination | stacking of the adhesive film on a polyimide film or copper foil, and lamination | stacking of the copper foil or polyimide film on an adhesive film were all implemented by 150 degreeC high temperature continuous lamination.

  The electrostatic chuck and the aluminum base material are bonded together by a vacuum press at 150 ° C./30 minutes, and after the vacuum press operation, a heat treatment at 150 ° C./12 hours is performed in a ventilated oven to complete the heat curing of the adhesive. Was done.

  Except that the polyimide film used for the adsorption surface is Upilex 75S (manufactured by Ube Industries, thickness 75 μm) instead of Kapton 200H, an electrostatic chuck is manufactured according to the same materials and working conditions as in Example 1, It stuck on the aluminum base material.

[Comparative Example 1]
As a comparative example, an electrostatic chuck having a first electrode and a second electrode, the layer configuration is exactly the same as the first mode, the second mode, and the third mode except that the second electrode is not embossed. With the same configuration, an electrostatic chuck having a suction surface size of 90 mm × 90 mm was prepared and adhered to an aluminum substrate.

  Next, the electrostatic chuck adhered to the aluminum base material obtained in Example 1, Example 2 and Comparative Example 1 was applied to the first electrode in an atmosphere of atmospheric pressure and pressure of 20 Pa, respectively at +1 kV or 0 kV, and the second When −1 kV is applied to the electrode, a glass plate having a size of 90 mm × 90 mm and a thickness of 1 mm is adsorbed, and the tensile strength in the vertical direction and the horizontal direction between the adsorption surface and the glass plate is compared by a load cell. Even in this case, it was confirmed that the electrostatic chucks of Example 1 and Example 2 according to the present invention having an embossed shape as the second electrode have a better attracting force.

It is a partial typical sectional view of an example of the electrostatic chuck of the 1st mode of the present invention. It is a partial schematic plan view of an example of the electrostatic chuck of the first aspect of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial typical sectional view of other examples of the electrostatic chuck of the present invention. It is a partial schematic plan view which shows an example of the electrode structure of the electrostatic chuck of the 2nd aspect of this invention. It is a top view of an example of the 1st electrode. It is a top view of other examples of the 1st electrode. It is a top view of an example of the 2nd electrode. It is a top view of other examples of the 2nd electrode. It is a top view of other examples of the 2nd electrode.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Insulating layer, 2 ... 1st electrode, 3 ... 2nd electrode, 4 ... Electrode protective layer, 5 ... Electrode protective layer, 6 ... Adhesive layer, 7 ... Base | substrate, 8 ... Electrode structure layer, 31, 52 DESCRIPTION OF SYMBOLS ... Embossed convex part, 32 ... Fine wire part, 33 ... Island-like electrode, 41 ... Mesh window, 42 ... Convex part, 51 ... Flat plate, 61 ... Electrode wire which comprises mesh, 62 ... Convex shape.

Claims (13)

  An insulating layer made of an insulating material, an electrode constituent layer made up of the first electrode and the second electrode, and an electrode protective layer made of an insulating material covering the surface of the electrode constituent layer, 1 electrode is a mesh electrode having a mesh pattern, the second electrode is a three-dimensional electrode having a number of embossed projections, and the second electrode has the insulating layer with respect to the first electrode. The convex portion is disposed so as to face toward the first electrode, and the convex portion is disposed at the position of the mesh window of the mesh pattern of the first electrode. Chuck.   An insulating layer made of an insulating material, an electrode constituent layer made up of the first electrode and the second electrode, and an electrode protective layer made of an insulating material covering the surface of the electrode constituent layer, One electrode is a mesh electrode having a mesh pattern, and the second electrode is a three-dimensional mesh pattern in which the mesh window position of the mesh pattern of the first electrode is convex and has an intersection at the position of the mesh window The second electrode is arranged through the insulating layer with respect to the first electrode, and when viewed through the electrode constituting layer from the vertical direction, the second three-dimensional network electrode An electrostatic chuck having a structure in which convex portions of a pattern are roughly arranged so as to face the first electrode side at a position of a mesh window of the first electrode.   The electrostatic chuck according to claim 1, wherein the convex portion of the second electrode penetrates the mesh window of the first electrode.   3. The electrostatic chuck according to claim 1, wherein an apex or a top surface of the convex portion of the second electrode is flush with the first electrode.   The electrostatic chuck according to claim 1, wherein a height dimension of the convex portion of the second electrode is shorter than a thickness dimension of the insulating layer.   6. The electrode protection layer according to claim 1, wherein a convex portion is provided by aligning a surface on the first electrode side serving as an electrostatic adsorption surface with a convex portion of the second electrode. The electrostatic chuck according to any one of the above.   The electrostatic chuck according to claim 6, wherein the unevenness of the electrode protective layer is a flow path for a temperature adjusting fluid.   The mesh line width of the mesh pattern of the first electrode is 0.01 mm or more and 5 mm or less, and the area of the mesh window is 0.5 mm 2 or more. 2. The electrostatic chuck according to claim 1.   9. The static according to claim 1, wherein a distance between portions of the first electrode and the second electrode excluding the convex portion is 0.01 mm or more. Electric chuck.   The electrostatic chuck according to claim 1, wherein the first electrode and the second electrode are made of a metal foil having a thickness of 150 μm or less.   11. The electrostatic chuck according to claim 1, wherein the electrode protective layer covering the surface of the electrode constituting layer is made of a polyimide film having a thickness of 12.5 to 300 μm.   The electrostatic chuck according to claim 1, wherein the insulating layer made of an insulating material is a polyimide film having a thickness of 12.5 to 300 μm.   The electrostatic chuck according to any one of claims 1 to 12, wherein the electrostatic chuck according to any one of claims 1 to 12 is attached to a substrate so that an electrode protective layer in contact with the first electrode is an adsorption surface. Electrostatic chuck.

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