JP2019187222A - Electrostatic chuck excellent in buffering - Google Patents

Abstract

To provide an electrostatic chuck with excellent buffering, which has a cushion unit made of a polyethylene foam material on a lower side of a chucking unit made of a polyimide material, thereby being excellent in buffering and restoration and thus capable of preventing damage to a substrate.SOLUTION: According to the present invention, an electrostatic chuck with excellent buffering includes: a chucking unit supporting a substrate with electrostatic force; a base plate provided on a lower portion of the chucking unit and supporting the chucking unit; and a cushion unit made of a plastic foam based material and disposed between the chucking unit and the base plate to prevent damage to the substrate supported on the chucking unit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a chuck, and more particularly, a cushioning portion made of a polyethylene foam material is provided under a chucking portion made of a polyimide material and has excellent buffering and restoring properties, thereby preventing damage to the substrate. The present invention relates to an electrostatic chuck with excellent buffering ability.

  In the next generation semiconductor and display panel process equipment, a chuck using electrostatic force is used as a core part to fix a wafer or a glass substrate. As the chuck, usually, two or more dielectric layers are formed on a base material and an electrode is inserted between the dielectric layers, and an insulating layer and a dielectric layer are formed on the base material. Examples include those in which an electrode is inserted between the layers. When a DC voltage is applied to the conductive electrode, the chuck generates a wafer or glass substrate that is the object to be processed by generating a reverse polarity in the wafer or glass substrate that is the object to be processed due to a dielectric polarization phenomenon. This is an apparatus for fixing a wafer or a glass substrate as an object to be processed using an electrostatic force generated between the substrate and a dielectric.

  On the other hand, conventionally, a chuck having a side of 1000 mm or more has been used as a single component so as to correspond to the size of the substrate for a liquid crystal panel. In this case, the conventional single chuck is made of a material having high hardness such as ceramic or metal material, and it is difficult to uniformly process the plane of the single electrostatic chuck. For this reason, conventionally, when a liquid crystal panel substrate is processed, a non-uniform load is applied to the liquid crystal panel substrate, and the liquid crystal panel substrate is frequently damaged.

  Furthermore, the conventional electrostatic attraction apparatus has a high manufacturing cost, and takes a high cost and a long processing time to give a uniform flatness during processing, and the degree of product defect is high. For this reason, there has been a demand for the development of an assembly-type electrostatic attraction apparatus capable of adsorbing a large substrate by arranging small chucks in an assembling manner. However, when assembling and using chucks to which a ceramic or metal support substrate having high hardness is applied, the processing dimensions of the chucks are different and the electrostatic adsorption forces are different. The present situation is that it is not possible to solve the problem of the electrostatic adsorption device.

  Currently, the chucking method is widely used not only in the display industry but also in the semiconductor industry. However, in the current situation, there are many accidents in which the above-mentioned problem occurs when a wafer is chucked and an expensive wafer is damaged.

  Therefore, a technique related to a chuck that can solve such a problem by providing a buffer member in the chuck is disclosed in Korean Patent Laid-Open No. 10-2007-99188. As a result, there still remains a problem that the load applied to the substrate cannot be absorbed normally.

  The technical problem to be solved by the present invention is to prevent the breakage of the substrate because the cushioning part and the restoring property are excellent because the cushioning part made of polyethylene foam material is arranged under the chucking part made of polyimide material. It is an object to provide an electrostatic chuck having excellent buffering performance.

  An electrostatic chuck excellent in shock-absorbing property according to the present invention for solving the technical problem described above is provided with a chucking part that supports a substrate using electrostatic force, and a lower part of the chucking part. A base plate that supports the king portion; and a cushion portion that is made of a plastic foam material and is disposed between the chucking portion and the base plate to prevent damage to the substrate supported by the chucking portion.

  Moreover, in this invention, it is preferable that the said cushion part has a thickness of 0.1-1 mm.

  Furthermore, in the present invention, the cushion part is preferably made of polyethylene foam.

Furthermore, in the present invention, the cushion part preferably has a compressive strength of 0.1 to 3 kgf / cm ² when the deformation rate is 25%.

  According to the chuck according to the present invention, since the cushion part made of polyethylene foam material is disposed under the chucking part made of polyimide material and has excellent buffering and restoring properties, it is possible to prevent the substrate from being damaged. A remarkable effect can be achieved.

It is a schematic cross section which shows the structure of the electrostatic chuck which was excellent in the buffer property which concerns on one Embodiment of this invention. It is a graph which shows the curve of the stress-deformation rate according to thickness of the polyethylene foam raw material which concerns on one Embodiment of this invention. It is a graph which shows the curve of the stress-deformation rate according to thickness of the polyethylene foam raw material which concerns on one Embodiment of this invention.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the electrostatic chuck 1 having excellent buffering properties according to the present embodiment includes a chucking portion 10, a base plate 20, and a cushion portion 30.

  First, the chucking unit 10 is a component that fixes and supports the substrate using an electrostatic force, and has a structure capable of generating the electrostatic force. Specifically, as shown in FIG. 1, the chucking unit 10 has a structure in which an electrode layer 13 is provided between the upper and lower dielectric layers 11 and 12 in a state where the upper and lower dielectric layers 11 and 12 are provided. You may have. The dielectric layers 11 and 12 are preferably a film made of a polyimide (PolyImide) material, and preferably have a thickness of about 20 to 100 μm.

  In addition, the electrode layer 13 may be formed to have a specific pattern, and may be disposed by a method of being attached between the upper and lower dielectric layers 11 and 12 in a state of being formed by a separate process. In addition to copper (Cu), which is a typical electrode material, it is preferably made of gold (Au), silver (Ag), tungsten (W), molybdenum (Mo), nickel (Ni), or the like.

  Next, as shown in FIG. 1, the base plate 20 is a component that forms the basis of the chuck 1 according to the present embodiment and has a plate shape as a whole, and supports the chucking portion 10 at a lower portion. Accordingly, the base plate 20 is preferably made of a metal material whose shape does not change, and more preferably an aluminum material.

  Next, as shown in FIG. 1, the cushion portion 30 is a component that is disposed between the chucking portion 10 and the base plate 20 and prevents breakage of the substrate supported by the chucking portion 10. Accordingly, the cushion part 30 is made of a plastic foam material having a buffering force, such as polyethylene foam (PolyEthylene Foam), polypropylene foam (PolyPropylene Foam), acrylic resin foam (Acrylic Foam), and polyurethane foam (PolyUrethan Foam). It is preferable to consist of a porous material.

  In particular, the cushion portion 30 is preferably made of polyethylene foam because it has excellent impact and resilience. This will be described in detail below.

The polyethylene foam preferably has a compressive strength of 0.1 to 3 kgf / cm ² when the deformation rate is 25%. At this time, the thickness of the polyethylene foam is preferably 0.1 to 1 mm. When the thickness of the polyethylene foam exceeds 1 mm, not only does it take a long time until the bonded object is subjected to sufficient pressure during the process, but there is a problem that the bonded object is difficult to receive sufficient pressure, There is a problem that the recoverability is significantly deteriorated. On the other hand, when it is less than 0.1 mm, there is a problem that the buffering property is inferior.

In the present invention, the polyethylene foam preferably has a cushion variation of 1.20% or more when a pressure of 0.1 kgf / cm ² is applied.

  As described above, when the cushion part 30 is formed from polyethylene foam, polypropylene foam (PolyPropylene Foam), acrylic resin foam (Acrylic Foam), and polyurethane foam (PolyUrethan Foam), the present inventors experimentally The effect was confirmed from the following Tables 1 and 2, and it was reconfirmed that the same result was obtained by actually applying the product. Tables 1 and 2 below are simple experimental results for helping understanding of the present invention, and it goes without saying that the scope of protection is not limited or limited.

  As shown in FIG. 2 and FIG. 3, such a polyethylene foam is improved in cushioning performance as the thickness of the polyethylene foam increases under the same compression deformation condition, and thus the cushioning performance is improved. If it exceeds, the restoring force will be reduced, it will be difficult to apply sufficient pressure to the bonded object, and it will take a long time, so it is not suitable for the chuck.

（表２）
加えられた圧力が０．１ｋｇｆ／ｃｍ^２であるときのクッションの変化量

このような特性を有するポリエチレンフォーム材質のクッション部は、上記表１及び２に記載されているように、同じ量の変化に必要な圧力が先行特許のシリコンラバーに比べてはるかに小さく、同じ圧力が加えられたときの変化量がはるかに多いということを確認することができ (Table 1)

(Table 2)
Cushion change amount when applied pressure is 0.1 kgf / cm ²

As described in Tables 1 and 2 above, the cushion part made of polyethylene foam material having such characteristics has a much smaller pressure required for the same amount of change than the silicone rubber of the prior patent, and the same pressure. You can see that the amount of change when

チャックに採用されるクッション部に必要な他の物性である復元力を測定するために、圧縮強度が２５％であるときの力で２４時間かけて圧力を加えた後、２２時間待った状態で厚さの変化量を測定する方式を利用する。 (Table 3)

In order to measure the restoring force, which is another physical property required for the cushion part employed in the chuck, after applying pressure for 24 hours with the force when the compressive strength is 25%, the thickness is waited for 22 hours. A method for measuring the amount of change in height is used.

  When the restoring force is measured by this method, as shown in Table 3 below, it can be seen that since the deformation value of the material made of polyethylene foam is small, the restoring property is most excellent.

  Meanwhile, the cushion portion 30 is adhered to the base plate 10 with an adhesive layer 40. Similarly, as shown in FIG. 1, an adhesive layer 50 is interposed between the cushion portion 30 and the lower dielectric layer 12 to firmly bond the two together.

DESCRIPTION OF SYMBOLS 1 Electrostatic chuck excellent in buffering property according to an embodiment of the present invention 10 Chucking portion 20 Base plate 30 Cushion portion 40 Adhesive layer

Claims (3)

A chucking portion that supports the substrate using electrostatic force;
A base plate disposed under the chucking portion and supporting the chucking portion;
A cushion part made of a plastic foam-based material and disposed between the chucking part and the base plate to prevent damage to the substrate supported by the chucking part;
An electrostatic chuck with excellent cushioning. The cushion part is
The electrostatic chuck having excellent buffering properties according to claim 1, wherein the electrostatic chuck has a thickness of 0.1 to 1 mm.
2. The electrostatic chuck having excellent buffering properties according to claim 1, wherein the electrostatic chuck is made of polyethylene foam. The cushion part is
The electrostatic chuck with excellent shock-absorbing property according to claim ² , wherein when the deformation rate is 25%, the compressive strength is 0.1 to 3 kgf / cm ² .

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