Electrostatic chucking jig

Abstract

To provide an electrostatic chucking tool that can obtain high chucking and gripping force by using a high electric field even with a low applied voltage and that can be used in a variety of processes. [Solution] The device comprises a support plate portion 2 formed of an insulating material, an upper electrode 3 formed on the upper surface, which is the adsorption surface side, of the support plate portion, and a lower electrode 4 arranged and formed on the lower surface of the support plate portion, wherein the upper electrode is formed of a plurality of linear electrode portions 3a adjacent to each other with a non-electrode portion 5 sandwiched therebetween, and a voltage is applied between the upper electrode and the lower electrode, and the plurality of linear electrode portions 3a are at the same potential.

Description

[Technical Field]

[0001] The present invention relates to an electrostatic chucking tool that attracts and holds an object to be attracted, such as a semiconductor wafer. [Background technology]

[0002] Electrostatic chucks have been used in semiconductor manufacturing processes and the like to attract and hold an object to be attracted (a workpiece) such as a semiconductor wafer by using Coulomb force to attract the charge within the object. Compared to mechanical chucks and vacuum chucks, electrostatic chucks are less likely to damage the object being chucked, and have been used in recent years as a means of chucking and gripping objects, particularly large and thin semiconductor wafers and LCD glass substrates.

[0003] For example, Patent Document 1 describes an electrostatic suction tool that has an electrode element group embedded inside an electrical insulating layer and an electrostatic suction force generating member that electrostatically suctions a thin object by applying a voltage to the electrode element group. In this electrostatic chucking tool, a group of electrode elements to which a positive voltage is applied and a group of electrode elements to which a negative voltage is applied are arranged side by side on the chucking surface side and embedded in an electrical insulating layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-101252 Summary of the Invention [Problem to be solved by the invention]

[0005] The above conventional techniques still have the following problems. The above-mentioned conventional electrostatic chucks and electrostatic adsorption tools have a disadvantage in that they have a weak gripping force for an object to be adsorbed, and therefore require the application of a high positive and negative voltage (e.g., 1000 V) to the electrode element group in order to increase the gripping force. Therefore, a thick insulating protective layer is required to cover the electrode element group to prevent the object to be adsorbed from coming into contact with the electrode element group to which the high positive and negative voltage is applied, causing dielectric breakdown. Furthermore, the insufficient gripping force limits the applicable manufacturing processes, making it particularly difficult to apply to processes in which the gripping force is reduced due to the penetration of moisture, or processes involving immersion or spraying.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an electrostatic chucking tool that can obtain high chucking and gripping forces due to a high electric field even with a low applied voltage, and that can be used in a variety of processes. [Means for solving the problem]

[0007] The present invention employs the following configuration to solve the above problems: That is, an electrostatic chucking jig of a first invention includes a support plate made of an insulating material, an upper surface electrode formed on the upper surface, which is the chucking surface side, of the support plate, and a lower surface electrode formed on the lower surface of the support plate, wherein the upper surface electrode is formed of a plurality of linear electrode portions adjacent to each other with a non-electrode portion sandwiched therebetween, and a voltage is applied between the upper surface electrode and the lower surface electrode, and the plurality of linear electrode portions are set to the same potential.

[0008] In this electrostatic chucking jig, the upper electrode is formed of multiple linear electrode portions adjacent to each other with non-electrode portions sandwiched between them, and a voltage is applied between the upper and lower electrodes, while the multiple linear electrode portions are at the same potential.As a result, electric field curves (electric force lines) seep upward from the non-electrode portions between the adjacent linear electrode portions, strengthening the electric field on the chucking surface and achieving a high chucking force for objects to be chucked, such as semiconductor wafers. This increases the average electric field strength on the plane of the adsorption surface, improving the electrostatic force and resulting in high adsorption and gripping forces. It also makes it possible to achieve a high electric field on the adsorption surface side even with a low applied voltage, and the reduction in circuit voltage makes it possible to achieve this with a low-load circuit. Conventional electrostatic chucks have a single-layer electrode structure in which both an electrode to which a positive voltage is applied and an electrode to which a negative voltage is applied are disposed on the same plane on the attracting surface side, and therefore an electric field is generated mainly in the planar direction. In contrast, in the electrostatic attracting jig of the present invention, a voltage is applied to a two-layer electrode structure in which an upper electrode and a lower electrode are disposed spaced apart from each other above and below, and therefore an electric field is generated mainly in the vertical direction. This makes it possible to generate a strong electric field from the non-electrode portions between the linear electrode portions toward the object to be attracted above, even when a low voltage is applied. Furthermore, because stronger adsorption and gripping forces can be achieved with a higher electric field than before, the technology is highly resistant to moisture penetration, making it possible to apply the technology to processes involving immersion or spraying.

[0009] The electrostatic chucking jig of the second invention is characterized in that, in the first invention, an insulating material is filled in the non-electrode portions between adjacent linear electrode portions, and the top surface is made flat. In other words, in this electrostatic suction jig, the non-electrode areas between adjacent linear electrode portions are filled with insulating material, and the top surface, which serves as the suction surface, is made flat, making it difficult for air or moisture to penetrate between the suctioned semiconductor wafer or the like, thereby achieving higher adhesion and suction properties.

[0010] The electrostatic chucking jig of the third invention is characterized in that, in the first or second invention, the upper surface electrode is a stripe-shaped electrode in which the multiple linear electrode portions extend in a fixed direction with spaces between each other. In other words, in this electrostatic suction jig, the upper surface electrode is a striped electrode in which multiple linear electrode portions extend in a fixed direction at intervals from each other, so that a strong electric field can be obtained above the linear non-electrode portions formed between the multiple linear electrode portions.

[0011] The electrostatic suction tool of the fourth invention is characterized in that, in the first or second invention, the upper surface electrode is a mesh electrode formed in a grid pattern by the plurality of linear electrode portions intersecting each other. In other words, in this electrostatic suction jig, the upper surface electrode is a mesh electrode formed by the intersection of multiple linear electrode portions in a grid pattern, so that a strong electric field can be obtained above the rectangular non-electrode portions formed between the multiple intersecting linear electrode portions.

[0012] The electrostatic suction tool of the fifth invention is characterized in that, in the first or second invention, the upper surface electrode is a spiral electrode formed by connecting the multiple linear electrode portions in a spiral shape. In other words, in this electrostatic suction jig, the upper surface electrode is a spiral electrode formed by connecting multiple linear electrode portions in a spiral shape, so that a strong electric field can be obtained above the spiral non-electrode portion formed between multiple linear electrode portions that are connected in a spiral shape in units of one turn, for example.

[0013] The electrostatic chucking tool of a sixth invention is the electrostatic chucking tool of any one of the first to fifth inventions, characterized in that the width of the linear electrode portion is 1 μm or more and 1000 μm or less. [Effects of the Invention]

[0014] According to the present invention, the following effects are achieved. That is, in the electrostatic chucking jig according to the present invention, the upper electrode is formed of a plurality of linear electrode portions adjacent to each other with non-electrode portions sandwiched therebetween, and a voltage is applied between the upper electrode and the lower electrode while the plurality of linear electrode portions are at the same potential. Therefore, a high electric field can be obtained even with a low applied voltage, and a high chucking force and gripping force can be obtained for an object to be chucked, such as a semiconductor wafer, and the jig can be adapted to a variety of processes. Therefore, the electrostatic chucking jig of the present invention is particularly suitable as a transport or process fixture in the post-processing of semiconductors. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a main part of a first embodiment of an electrostatic chucking jig according to the present invention. [Figure 2] 4 is a conceptual diagram showing an electric field curve from a non-electrode portion between linear electrode portions in the first embodiment. FIG. [Figure 3] FIG. 2 is a perspective view of a main part showing the upper surface of the electrostatic chucking jig in the first embodiment. [Figure 4] FIG. 2 is a perspective view showing an electrostatic chucking jig in the first embodiment. [Figure 5] FIG. 11 is a perspective view of a main part showing the upper surface of the electrostatic chucking jig in the second embodiment. [Figure 6] FIG. 11 is a perspective view of a main part showing the upper surface of the electrostatic chucking jig in the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] A first embodiment of an electrostatic chucking tool according to the present invention will be described below with reference to Fig. 1 to Fig. 4. Note that in the drawings used in the following description, the scale has been appropriately changed so that each component is recognizable or easily recognizable.

[0017] As shown in Figures 1 to 4, the electrostatic suction jig 1 of this embodiment comprises a support plate portion 2 made of an insulating material, an upper surface electrode 3 formed on the upper surface, which is the suction surface side, of the support plate portion 2, and a lower surface electrode 4 formed on the lower surface of the support plate portion 2 and arranged opposite the upper surface electrode 3. The support plate portion 2 has the upper surface on which the upper electrode 3 is formed, and the lower surface opposite to the upper surface on which the lower electrode 4 is formed. The upper surface electrode 3 is formed of a plurality of linear electrode portions 3a adjacent to each other with non-electrode portions 5 sandwiched therebetween. In the electrostatic chucking jig 1 of this embodiment, a voltage is applied between the upper electrode 3 and the lower electrode 4, and the plurality of linear electrode portions 3a are set to the same potential.

[0018] Even if the electrostatic chucking jig 1 of this embodiment is detached from the power supply mechanism after voltage has been applied thereto, the electrostatic chucking jig 1 can retain charge due to the capacitor structure of the upper electrode 3 and the lower electrode 4, which are spaced apart vertically, and can therefore maintain the state of chucking the object to be attracted. That is, the electrostatic chucking jig 1 of this embodiment can be used not only as an electrostatic chuck that attracts an object to be attracted by applying a voltage from a power supply mechanism, but also as a portable jig that can be transported individually while attracting an object to be attracted even when separated from the power supply mechanism. In this case, the attracting state can be released by removing the charge from the electrostatic chucking jig 1 in the attracting state.

[0019] In the electrostatic chucking jig 1 of this embodiment, the non-electrode portions 5 between adjacent linear electrode portions 3a are filled with an insulating material, and the uppermost surface serving as the chucking surface is made flat. In other words, the upper surfaces of the linear electrode portions 3a and the upper surface of the insulating material filling the non-electrode portions 5 are flush with each other. In the electrostatic chucking jig 1 of this embodiment, a substrate 6 is adhered to the lower surface of the lower electrode 4, and the entire jig is formed in a disk shape corresponding to the shape and size of the object to be chucking, such as a semiconductor wafer.

[0020] As shown in FIG. 3, the upper surface electrode 3 is a stripe-shaped electrode in which a plurality of linear electrode portions 3a extend in a fixed direction at intervals from one another. As shown in FIG. 4, the upper electrode 3 includes an equal potential electrode portion 3c that extends in a circular shape on the outer edge of the upper surface of the support plate portion 2 and is connected to all of the linear electrode portions 3a. That is, during use, for example, by applying a voltage of 0V to the equipotential electrode portion 3c and +1000V to the lower electrode 4, all of the connected linear electrode portions 3a are at the same potential of 0V.

[0021] The upper electrode 3 (the linear electrode portion 3a and the equipotential electrode portion 3c) is made of a noble metal such as Au, Ag, Pt, etc. By making the upper electrode 3 of such a noble metal, it is possible to prevent oxidation over time and maintain hydrophobicity for a long period of time. The lower electrode 4 is made of, for example, Cu, and is a so-called solid electrode formed in a circular shape to cover the entire lower surface. The non-electrode portion 5 is an area between adjacent linear electrode portions 3a where no electrode is present, and as the insulating material filling the non-electrode portion 5, for example, a resin such as polyimide can be used.

[0022] The support plate portion 2 is made of a resin such as polyimide. The base material 6 is made of an insulating material such as a resin such as polycarbonate or glass. A thin protective layer made of an insulating material may be formed on the upper surfaces of the upper electrode 3 and the non-electrode portion 5 filled with the insulating material. For example, by forming the protective layer from an organic polymer compound that is a fluororesin such as PTFE (polytetrafluoroethylene), hydrophobicity with a contact angle of 90° or more can be obtained.

[0023] The linear electrode portion 3a is formed in a rectangular cross section, for example, 100 μm wide and 100 μm thick. The linear electrode portion 3a has a predetermined width sufficient to function as an electrode, and the width is preferably, for example, 1 μm to 1000 μm. The interval between adjacent linear electrode portions 3a (the width of the non-electrode portion 5) is set to, for example, 50 μm. The interval between adjacent linear electrode portions 3a is preferably in the range of 10 to 200 μm. The thickness of the support plate 2 is set to, for example, 1 to 200 μm. That is, the vertical distance between the upper electrode 3 and the lower electrode 4 is set to, for example, 1 to 200 μm.

[0024] As described above, in the electrostatic chucking jig 1 of this embodiment, the upper electrode 3 is formed of a plurality of adjacent linear electrode portions 3a with non-electrode portions 5 sandwiched therebetween, and a voltage is applied between the upper electrode 3 and the lower electrode 4, and the plurality of linear electrode portions 3a are set to the same potential. As a result, as shown in FIG. 2, the electric field curve (electric force lines) E seeps out upward from the non-electrode portions 5 between the adjacent linear electrode portions 3a, thereby strengthening the electric field on the chucking surface and enabling a high chucking force to be obtained for an object to be chucked, such as a semiconductor wafer.

[0025] That is, in this embodiment, the upper electrode 3 is a stripe-shaped electrode in which multiple linear electrode portions 3a extend in a fixed direction at intervals from each other, so that a strong electric field can be obtained above the linear non-electrode portions 5 formed between the multiple linear electrode portions 3a. This increases the average electric field strength on the plane of the adsorption surface, improving the electrostatic force and resulting in high adsorption and gripping forces. It also makes it possible to achieve a high electric field on the adsorption surface side even with a low applied voltage, and the reduction in circuit voltage makes it possible to achieve this with a low-load circuit.

[0026] In a conventional electrostatic chuck, an electrode to which a positive voltage is applied and an electrode to which a negative voltage is applied are both disposed on the same plane on the attracting surface side, and therefore an electric field is generated mainly in a planar direction. In contrast, in the electrostatic attracting jig 1 of the present embodiment, a voltage is applied to a two-layer electrode structure consisting of an upper electrode 3 and a lower electrode 4 disposed spaced apart from each other above and below, and therefore an electric field is generated mainly in a vertical direction. This makes it possible to generate a strong electric field from the non-electrode portions 5 between the linear electrode portions 3 a toward the object to be attracted above, even when a low voltage is applied.

[0027] Furthermore, the electrostatic suction jig 1 of this embodiment can obtain a stronger suction and gripping force at a higher electric field than conventional ones, and therefore has high resistance to moisture penetration, making it applicable to processes involving immersion or spraying. Furthermore, since the non-electrode portions 5 between adjacent linear electrode portions 3a are filled with an insulating material and the top surface, which serves as the adsorption surface, is made flat, air and moisture are less likely to penetrate between the adsorbed semiconductor wafer, etc., and higher adhesion and adsorption properties can be achieved.

[0028] Next, second and third embodiments of the electrostatic chucking tool according to the present invention will be described below with reference to Figures 5 and 6. In the following description of each embodiment, the same components as those described in the above embodiments will be denoted by the same reference numerals, and their description will be omitted.

[0029] The second embodiment differs from the first embodiment in that, in the first embodiment, the upper surface electrode 3 is a striped electrode in which a plurality of linear electrode portions 3a extend in a fixed direction at intervals from each other, whereas, in the electrostatic chucking jig 21 of the second embodiment, the upper surface electrode 23 is a mesh electrode in which a plurality of linear electrode portions 23a intersect to form a lattice pattern, as shown in FIG. 5.

[0030] In the second embodiment, all of the linear electrode portions 23a are connected to each other and are conductive, so the equal-potential electrode portion 3c of the first embodiment is not necessary, and all of the linear electrode portions 23a will be at the same potential if an external voltage is applied to any of the linear electrode portions 23a. As described above, in the electrostatic chucking jig 21 of the second embodiment, the upper surface electrode 23 is a mesh electrode in which a plurality of linear electrode portions 23a are intersected to form a grid, and therefore a strong electric field can be obtained above the rectangular non-electrode portions 23b formed between the intersecting linear electrode portions 23a.

[0031] Next, the third embodiment differs from the first embodiment in that, whereas in the first embodiment, the upper surface electrode 3 is a striped electrode in which a plurality of linear electrode portions 3a extend in a fixed direction at intervals from one another, in the electrostatic chucking jig 31 of the third embodiment, as shown in FIG. 6, the upper surface electrode 33 is a spiral electrode formed by a plurality of linear electrode portions 33a connected in a spiral shape.

[0032] As described above, in the electrostatic chucking jig 21 of the second embodiment, the upper surface electrode 33 is a spiral electrode formed by connecting a plurality of linear electrode portions 33a in a spiral shape, and therefore, a strong electric field can be obtained above the spiral non-electrode portion 33b formed between the plurality of linear electrode portions 33a connected in a spiral shape in units of one turn, for example.

[0033] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0034] For example, in each of the above embodiments, linear electrode portions that extend with a constant width are used, but it is also possible to use linear electrode portions whose width varies or that extend in a serpentine manner instead of a straight line. Furthermore, in each of the above embodiments, the linear electrode portions extend regularly, such as in a striped, mesh, or spiral pattern, but it is also possible to use an electrostatic suction jig in which multiple linear electrode portions are arranged irregularly on the upper surface of the support plate portion. [Explanation of symbols]

[0035] 1.21,31…Electrostatic attraction fixture, 2…Support plate, 3.23,33…Upper electrode, 4…Lower electrode, 3a,23a,33a…Linear electrode section

Claims

1. a support plate portion formed of an insulating material; an upper surface electrode formed on an upper surface of the support plate portion, which is an adsorption surface side; a lower surface electrode formed on the lower surface of the support plate portion, the upper surface electrode is formed of a plurality of linear electrode portions adjacent to each other with non-electrode portions interposed therebetween, An electrostatic chucking jig, characterized in that a voltage is applied between the upper electrode and the lower electrode, and the plurality of linear electrode portions are set to the same potential.

2. 2. The electrostatic chucking jig according to claim 1, An electrostatic chucking jig, characterized in that an insulating material is filled in the non-electrode portions between adjacent linear electrode portions, and the uppermost surface is made flat.

3. 3. The electrostatic chucking jig according to claim 1, The electrostatic chucking jig is characterized in that the upper surface electrode is a stripe-shaped electrode in which the plurality of linear electrode portions extend in a fixed direction at intervals from each other.

4. 3. The electrostatic chucking jig according to claim 1, The electrostatic chucking jig is characterized in that the upper surface electrode is a mesh electrode formed in a lattice shape by the plurality of linear electrode portions intersecting each other.

5. 3. The electrostatic chucking jig according to claim 1, The electrostatic chucking tool is characterized in that the upper surface electrode is a spiral electrode formed by connecting the plurality of linear electrode portions in a spiral shape.

6. 3. The electrostatic chucking jig according to claim 1, An electrostatic chucking jig characterized in that the width of the linear electrode portion is 1 μm or more and 1000 μm or less.

Images