TW201314815A - Electrostatic chuck and manufacturing method thereof - Google Patents

Abstract

An electrostatic chuck includes a substrate, an electrode layer, and a mixed dielectric material. The electrode layer is configured to induce electrostatic force and disposed on the substrate. The mixed dielectric material covers the electrode layer, including a first polymer and a plurality of electrically conductive particles, wherein the volume resistivity of the mixed dielectric material is between 10<SP>8</SP> and 10<SP>12</SP> ohm-centimeter.

Description

Electrostatic chuck and manufacturing method thereof

The present invention relates to an electrostatic chuck.

An electrostatic chuck typically includes at least one electrode and a dielectric layer overlying the electrode. A voltage is applied to at least one of the electrodes such that the electrostatic chuck and the transporting workpiece respectively collect electrically opposite charges, and the workpiece is adsorbed by an electrostatic force generated between the opposite charges. The electrostatic chuck can be distinguished according to the mechanism of action of the material of the dielectric layer and the electrostatic force. In general, there are two types of electrostatic chucks: the Coulomb chuck and the Johnsen Rahbek chuck.

The dielectric layer of the Coulomb electrostatic chuck has a high resistance value (eg, greater than 10 ¹² ohms ‧ cm). When a voltage is applied to the electrodes, the electrodes concentrate the charge and the opposite charges are accumulated on the workpiece, two of which are separated by a dielectric layer.

The electrostatic pressure (P) of a monopolar Coulomb electrostatic chuck can be expressed by the following formula:

Among them, F table electrostatic force, A is the electrode area, V _o is the applied voltage, ε ₀ is the permittivity of air gap, K is the relative permittivity of the dielectric layer, t _D It is the thickness of the dielectric layer, and δ is the total gap between the workpiece and the surface of the dielectric layer.

It can be seen from the formula (1) that the electrostatic pressure is inversely proportional to the dielectric layer thickness (t _D ). Therefore, in order to obtain a large electrostatic pressure, the thickness of the general Coulomb electrostatic chuck dielectric layer is preferably as small as possible.

The dielectric layer of the Johnson Labeck electrostatic chuck has a finite resistance value. When a voltage is applied to the electrode, current flows through the dielectric layer and the workpiece, forming a charge layer between the dielectric layer and the workpiece, resulting in a stronger Appeal. The electrostatic pressure generated by the Johnson Labec electrostatic chuck can be distinguished by the portion of the Coulomb effect and the portion produced by the Johnson Labeb effect. Usually the Coulomb effect is too small to be negligible.

The dielectric layer of the Coulomb type electrostatic chuck is usually made of a polymer material such as polyimide (PI) or polyethylene (PE). The thickness of the dielectric layer is typically less than 100 microns to maintain high electrostatic forces. However, thin PI or PE dielectric layers are susceptible to damage, particularly when particles are present on the workpiece, which may scratch the PI or PE dielectric layer when the thin PI or PE dielectric layer is in intimate contact with the workpiece.

The dielectric layer of the Johnson Labeke electrostatic chuck can be made of ceramic materials such as sintered alumina or aluminum nitride. The sintered dielectric layer is glued to a pedestal and covers the electrodes on the pedestal. Since the dielectric layer needs to be separately sintered and then fixed by gluing, the manufacturing process is complicated, and when the bonding is performed, the bonding failure is liable to occur. In addition, the raw embryos are prepared in advance according to the susceptor and then sintered. It is quite inconvenient to make different raw embryos for different shapes of the base. Furthermore, as the handling of the workpiece is increased, larger electrostatic chucks are also required; large ceramic dielectric layers are not easily sintered and combined, and large ceramic dielectric layers are heavy and unfavorable for use.

One aspect of the invention provides an electrostatic chuck that is lighter than an electrostatic chuck that uses a ceramic dielectric layer.

Another aspect of the present invention provides an electrostatic chuck that can be used in an adsorbent glass or a poly(ethylene terephthalate) film.

Yet another aspect of the present invention provides an electrostatic chuck that is electrostatically adsorbed to carry a workpiece by Johnson Labebeck.

An embodiment of the invention provides an electrostatic chuck comprising a substrate, an electrode layer, and a hybrid dielectric material. The electrode layer is used to generate electrostatic attraction, wherein the electrode layer is disposed on the substrate. A mixed dielectric material covers the electrode layer. The mixed dielectric material comprises a first polymer material and a plurality of conductive particles, wherein the mixed dielectric material has a bulk resistance of from 10 ⁸ to 10 ¹² ohms ‧ cm.

Another embodiment of the present invention provides an electrostatic chuck comprising a substrate, an electrode layer, and a mixed dielectric material. The electrode layer is used to generate electrostatic attraction, wherein the electrode layer is disposed on the substrate. A mixed dielectric material covers the electrode layer. The mixed dielectric material comprises a first polymer material and a plurality of conductive particles, wherein the conductive particles are between 3% and 30% by weight based on the total weight of the mixed dielectric material.

According to still another aspect of the present invention, a method for fabricating an electrostatic chuck includes the steps of: mixing a plurality of conductive particles into a polymer material to obtain a mixed solution; and coating the mixed solution on a substrate to form a coating layer. And hardening the coating to obtain a mixed dielectric material, wherein the mixed dielectric material has a bulk resistance of from 10 ⁸ to 10 ¹² ohms ‧ cm.

The technical features and advantages of the present disclosure have been broadly described above, and the detailed description of the present disclosure will be better understood. Other technical features and advantages of the subject matter of the claims of the present disclosure will be described below. It will be appreciated by those skilled in the art that the present invention may be practiced with the same or equivalents. It is also to be understood by those of ordinary skill in the art that this invention is not limited to the spirit and scope of the disclosure as defined by the appended claims.

Fig. 1 is a cross-sectional view showing an electrostatic chuck 1 according to an embodiment of the present invention. Referring to FIG. 1, the electrostatic chuck 1 includes a substrate 11, an electrode layer 13, and a mixed dielectric material 14. The electrode layer 13 is used to generate electrostatic attraction, wherein the electrode layer 13 is disposed on the substrate 11. The hybrid dielectric material 14 covers the electrode layer 13.

2 shows a schematic diagram of a hybrid dielectric material 14 in accordance with an embodiment of the present invention. Referring to Figure 2, the hybrid dielectric material 14 has a finite resistivity such that the electrostatic chuck 1 can be a Johnson Labec electrostatic chuck. The hybrid dielectric material 14 may include a polymer material 141 and a plurality of conductive particles 142, wherein a plurality of conductive particles 142 are mixed in the polymer material 141.

The polymer material 141 may have a high body resistance value, for example, a body resistance value greater than 10 ¹⁴ ohms ‧ cm. In an embodiment, the polymer material 141 may comprise an epoxy resin, a silicone, an acrylic or a polystyrene, or the like.

A plurality of conductive particles 142 are mixed with the high molecular resistance 141, thereby obtaining a lower dielectric resistance mixed dielectric material 14. The conductive particles 142 may comprise a metal such as silver, copper or the like. Conductive particles 142 may also comprise a metal oxide such as titanium dioxide (TiO ₂ ), tin dioxide (SnO ₂ ), zinc oxide (ZnO) or the like. Further, the conductive particles 142 may include nano metal particles such as silver nanoparticles, copper nanoparticles or the like. The conductive particles 142 may also contain nano metal oxide particles such as titanium dioxide nanoparticles, tin dioxide nanoparticles, zinc oxide nanoparticles or the like.

By mixing a sufficient amount of the conductive particles 142 in the polymer material 141, a mixed dielectric material 14 having a low bulk resistance can be obtained. The mixed dielectric material 14 having a lower body resistance value allows current to flow therethrough when the voltage is applied to the electrode layer 13. In an embodiment, the hybrid dielectric material 14 can be between 10 ⁸ and 10 ¹² ohms ‧ cm. As such, when a voltage is applied to the electrode layer 13, current can flow through the hybrid dielectric material 14 to form a charge layer between the hybrid dielectric material 14 and the workpiece.

By changing the mixing amount of the plurality of conductive particles 142, the body resistance of the mixed dielectric material 14 can be adjusted so that the electrostatic chuck 1 can be a Johnson Labec electrostatic chuck. In one embodiment, the weight of the plurality of electrically conductive particles 142 is between 3% and 30%, based on the total weight of the mixed dielectric material 14. The mixed dielectric material 14 is mixed with 3% to 30% by weight of the conductive particles 142 to obtain a mixed dielectric material 14 having a volume resistance value of from 10 ⁸ to 10 ¹² ohms ‧ cm.

Since the hybrid dielectric material 14 has a lower bulk resistance, current can flow through the hybrid dielectric material 14 to form a charge layer between the hybrid dielectric material 14 and the workpiece, such that the electrostatic chuck 1 can utilize Johnson Labec force. Adsorb the workpiece, not just the Coulomb force. Due to this effect, the thickness of the mixed dielectric material 14 on the substrate 11 can be increased without affecting the electrostatic attraction of the electrostatic chuck 1. The thicker hybrid dielectric material 14 can have greater mechanical strength, is less susceptible to damage, and is particularly less susceptible to particle scratching. In one embodiment, the thickness of the hybrid dielectric material 14 on the substrate 11 can be greater than 100 microns. In another embodiment, the thickness of the hybrid dielectric material 14 on the substrate 11 can be between 200 microns and 500 microns.

Further, the electrostatic chuck 1 made of the mixed dielectric material 14 is lighter in weight than the sintered ceramic material, and is convenient to use.

A plurality of conductive particles 142 are mixed in a liquid polymer material, and the mixed solution is applied to the substrate 11 to form a coating layer. After the coating layer is hardened, the mixed dielectric material 14 is obtained. In one embodiment, the method of applying the mixed liquid comprises methods such as spin coating, brush coating, or soaking.

The material of the substrate 11 can be determined for the application, or as determined by the processing of the overlying layer. In the present embodiment, the substrate 11 contains a metal including aluminum, aluminum alloy, stainless steel, or the like. Alternatively, the substrate 11 can have any shape, the shape of which can be determined according to the needs of the application.

Referring to FIG. 1 , when the substrate 11 comprises a metal, the electrostatic chuck 1 may further comprise a polymer material 12 disposed between the substrate 11 and the electrode layer 13 to electrically isolate the substrate 11 and the electrode layer 13 . . In an embodiment, the polymeric material 12 may comprise an epoxy resin, a sulfhydryl resin, an acrylate or a polystyrene. The thickness of the polymer material 12 needs to be sufficient to electrically isolate the substrate 11 from the electrode layer 13. In one embodiment, the polymer material 12 may have a thickness of about 0.1 to 1.0 millimeter.

Referring to FIG. 1, the electrode layer 13 is formed on the polymer material 12. The electrode layer 13 is coupled to a power supply 16 by a wire 15, thereby providing a voltage so that the electrostatic chuck 1 can adsorb the workpiece. The material of the electrode layer 13 may comprise molybdenum or tungsten. In one embodiment, the electrode layer 13 is fabricated by a printing process.

Fig. 3 is a cross-sectional view showing an electrostatic chuck 1' according to an embodiment of the present invention. Referring to FIG. 3, the electrostatic chuck 1' includes a substrate 11', an electrode layer 13 as described above, and a hybrid dielectric material 14 as described above. The substrate 11' contains an insulating material. The electrode layer 13 is formed directly on the substrate 11'. The hybrid dielectric material 14 covers the electrode layer 13.

In the present embodiment, the substrate 11' may include a protrusion 111 formed on a surface 112 of the substrate 11'. The electrode layer 13 is formed on the surface of the projection 111. The hybrid dielectric material 14 covers the projections 111 and the surface 112 and extends to the side surface of the substrate 11' as shown in FIG.

In an embodiment, the material of the substrate 11' may be made of a material such as quartz or ceramic.

In one embodiment, the electrode layer 13 is coupled to a power supply 16 by a wire 15, thereby providing a voltage such that the electrostatic chuck 1' can adsorb the workpiece. The material of the electrode layer 13 may comprise molybdenum or tungsten. The electrode layer 13 can be formed on the projections 111 of the substrate 11' by thermal spraying, wherein the thermal spraying includes flame spraying, plasma spraying, arc spraying, spray gun spraying, and high-speed oxygen/fuel spraying. In another embodiment, the electrode layer 13 is formed by a deposition process.

The mixed dielectric material 14 covers the substrate 11'. In one embodiment, the mixed dielectric material 14 can be made of a mixture comprising conductive particles 142 and a polymer solution, and the mixture can be coated by spin coating or brush coating. Or soaking or the like to cover the substrate 11'.

The technical content and the technical features of the present disclosure have been disclosed as above, but those skilled in the art should understand that the teachings and disclosures of the present disclosure are disclosed without departing from the spirit and scope of the disclosure as defined by the appended claims. Can be used for various substitutions and modifications. For example, many of the processes disclosed above may be implemented in different ways or in other processes, or a combination of the two.

Moreover, the scope of the present invention is not limited to the particular process, machine, manufacture, composition, means, method or method of the particular embodiments disclosed. It should be understood by those of ordinary skill in the art that, based on the teachings of the present disclosure, the process, the machine, the manufacture, the composition of the material, the device, the method, or the steps, whether present or future developers, The revealer performs substantially the same function in substantially the same manner, and achieves substantially the same result, and can also be used in the present disclosure. Accordingly, the scope of the following claims is intended to cover such <RTIgt; </ RTI> processes, machines, manufactures, compositions, devices, methods or steps.

1, 1'. . . Electrostatic chuck

11, 11'. . . Base

12. . . Polymer Materials

13. . . Electrode layer

14. . . Mixed dielectric material

15. . . wire

16. . . Power Supplier

111. . . Protrusion

112. . . surface

141. . . Polymer Materials

142. . . Conductive particles

Figure 1 is a cross-sectional view showing an electrostatic chuck according to an embodiment of the present invention;

2 shows a schematic view of a hybrid dielectric material in accordance with an embodiment of the present invention;

Figure 3 is a cross-sectional view showing an electrostatic chuck according to an embodiment of the present invention.

1. . . Electrostatic chuck

11. . . Base

12. . . Polymer Materials

13. . . Electrode layer

14. . . Mixed dielectric material

15. . . wire

16. . . Power Supplier

Claims (20)

An electrostatic chuck comprising: a substrate; an electrode layer disposed on the substrate, the electrode layer for generating electrostatic attraction; and a mixed dielectric material covering the electrode layer, the mixed dielectric material comprising a first high The molecular material and the plurality of conductive particles, wherein the mixed dielectric material has a bulk resistance value of 10 ⁸ to 10 ¹² ohms ‧ cm. The electrostatic chuck according to claim 1, wherein the first polymer material has a bulk resistance greater than 10 ¹⁴ ohms ‧ cm. The electrostatic chuck according to claim 1, wherein the conductive particles are nano metal particles or metal oxides. The electrostatic chuck according to claim 1, wherein each of the conductive particles comprises titanium oxide, tin dioxide, zinc oxide, silver or copper. The electrostatic chuck according to claim 1, wherein the first polymer material comprises an epoxy resin, a sulfhydryl resin, an acrylate or a polystyrene. The electrostatic chuck according to claim 1, wherein the substrate comprises an insulating material, and the electrode layer is formed directly on the substrate. The electrostatic chuck of claim 6, wherein the substrate comprises quartz or ceramic. The electrostatic chuck according to claim 1, further comprising a second polymer material, wherein the second polymer material is interposed between the substrate and the electrode layer. The electrostatic chuck of claim 8, wherein the substrate comprises a metal. An electrostatic chuck comprising: a substrate; an electrode layer disposed on the substrate, the electrode layer for generating electrostatic attraction; and a mixed dielectric material covering the electrode layer, the mixed dielectric material comprising a polymer material And a plurality of metal particles, wherein the metal particles are between 3% and 30% by weight based on the total weight of the mixed dielectric material. The electrostatic chuck according to claim 10, wherein the mixed dielectric material has a bulk resistance of from 10 ⁸ to 10 ¹² ohms ‧ cm. The electrostatic chuck according to claim 10, wherein the first polymer material has a bulk resistance greater than 10 ¹⁴ ohms ‧ cm. The electrostatic chuck according to claim 10, wherein the conductive particles are nano metal particles or metal oxides. The electrostatic chuck according to claim 10, wherein each of the conductive particles comprises titanium dioxide, tin dioxide, zinc oxide, silver or copper. The electrostatic chuck according to claim 10, wherein the first polymer material comprises an epoxy resin, a sulfhydryl resin, an acrylate or a polystyrene. The electrostatic chuck according to claim 10, wherein the substrate comprises an insulating material, and the electrode layer is formed directly on the substrate. The electrostatic chuck of claim 16, wherein the substrate comprises quartz or ceramic. The electrostatic chuck according to claim 10, further comprising a second polymer material, wherein the second polymer material is interposed between the substrate and the electrode layer. The electrostatic chuck of claim 18, wherein the substrate comprises a metal. A method for manufacturing an electrostatic chuck, comprising the steps of: mixing a plurality of conductive particles into a polymer material to obtain a mixed solution; applying the mixed solution to a substrate to form a coating; and hardening the coating Obtaining a mixed dielectric material, wherein the mixed dielectric material has a bulk resistance of from 10 ⁸ to 10 ¹² ohms ‧ cm.