KR20060003490A - Electrode static chuck - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic chuck for wafer holding in a semiconductor manufacturing apparatus, wherein an edge region of the dielectric plate is refracted in an electrostatic chuck including a dielectric plate, a cooling plate, and a connection film for joining the dielectric plate and the cooling plate. . Here, the upper edge region of the dielectric plate on which the wafer is held may be refracted, or the edge region of the surface on which the dielectric plate and the cooling plate are coupled may be refracted. In this way, a predetermined path difference can be given to the edge of the indium film that bonds the ceramic plate and the cooling plate of the electrostatic chuck to prevent damage to the indium film by an external plasma. By eliminating the gap, the contact can be improved, and the outer space of the ceramic plate and cooling plate can be reduced to 5 mm or less, thereby making the bonding area wider, and extending the life of the electrostatic chuck.

Electrostatic chuck, path difference, indium film, ceramic plate, cooling plate, chamber, wafer

Description

Electrostatic chuck

1 is a cross-sectional view of an electrostatic chuck according to the prior art.

2A and 2B are conceptual views for briefly explaining the technical principle of the electrostatic chuck according to the present invention.

3A is a cross-sectional view of an electrostatic chuck according to a first embodiment of the present invention, and FIG. 3B is a conceptual diagram of separation of the electrostatic chuck according to the first embodiment of the present invention. 3C to 3E are conceptual views illustrating a deformable example of the region A of FIG. 3A.

4 is a cross-sectional view of the electrostatic chuck with the opposite step of FIG. 3A.

5A and 5B are cross-sectional views of an electrostatic chuck according to a second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

2, 112: electrode 10, 110: ceramic plate

20, 30, 120: cooling plate 40, 130: indium film

50: O-ring 140: groove

150: refraction plate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing apparatus, and more particularly, to an electrostatic chuck (ESC) for wafer holding used in the manufacture of semiconductor devices.

In general, a semiconductor device is formed through a plurality of processes including a process of depositing and etching certain materials on a wafer. Each of these processes is carried out in a chamber, each of which is a hermetically sealed container having its own unique working environment. In the chamber, a chuck, which is usually a means for fixing a wafer, is installed to support a wafer loaded into the chamber.

The chuck is classified into a mechanical chuck, a vacuum chuck, and an electrostatic chuck according to a method of fixing a wafer. A mechanical chuck refers to a chuck using a fixing means having a physical gripping force such as an arm or a clamp for fixing a wafer seated on a support surface. Such a mechanical chuck has a disadvantage in that the grip force on the wafer is nonuniform, resulting in uneven contact between the wafer and the chuck guy, causing deformation of the wafer. Vacuum chuck also refers to a chuck that causes the wafer to be gripped by lowering the pressure in the space between the wafer and the chuck to less than the pressure inside the chamber. However, there is a disadvantage in that the semiconductor does not exhibit proper gripping force due to uneven pressure in the chamber during the manufacturing process.

Thus, the electrostatic chuck has been developed to maintain a uniform grip between the wafer and the support. The electrostatic chuck uses a method of fixing and supporting the wafer by using the voltage difference between the wafer and the electrode installed inside the chuck. Such electrostatic chucks are widely used to support wafers in vapor deposition apparatuses or chamber apparatuses for etching.

1 is a cross-sectional view of an electrostatic chuck according to the prior art.

Referring to FIG. 1, the electrostatic chuck includes a ceramic plate 10 having internal electrodes 2 embedded therein, and internal and external cooling plates for dissipating heat from ceramic plate 10 under the ceramic plate 10. 20 and 30. In general, the electrostatic chuck inside the deposition chamber using the high density plasma uses indium 40, in which bonding between the ceramic plate 10 and the internal cooling plate 20 can serve as a buffer.

However, the indium 40 is damaged due to NF ₃ generated during the cleaning process, causing the problem that the indium bonding 40 falls. In order to solve this problem, a method of sealing the outermost part of the coupling surface between the ceramic plate 10 and the cooling plate 20 by using an O-ring 50 is used. That is, the O-ring 50 serving as a barrier is positioned at the outermost portion of the region where the indium 40 is bonded to prevent damage to the indium 40 due to the plasma generated inside the chamber.

When the above-described O-ring 50 is used, damage to the indium bonding 50 due to NF ₃ plasma generated inside the chamber can be prevented as mentioned above, but the O-ring 50 may be replaced with a ceramic plate ( There are many problems due to the addition between 10) and the cooling plate 20.

First, since the temperature of the portion where the ceramic plate 10 is not bonded to the cooling plate 20 is high, the O-ring 50 damage is damaged by NF ₃ plasma, and particles are generated by the damage. Problem occurs. In addition, a problem arises in that the O-ring 50 needs to be replaced periodically due to damage.

In addition, the cooling plate 20 uses a material having excellent thermal conductivity, whereas the O-ring 50 uses a material having low thermal conductivity. Therefore, a difference in thermal conductivity occurs in a portion where the O-ring 50 is present in the lower portion of the ceramic plate 10. As a result, a stress due to heat is generated in the ceramic plate 10 and eventually causes a problem that the ceramic plate 10 is destroyed when used for a long time.

Therefore, the present invention can prevent damage to the indium bonding by the plasma generated inside the chamber by providing a predetermined step in the outermost region of the dielectric plate in order to solve the above problems, and because the O-ring is not used It provides an electrostatic chuck that can strengthen the coupling between the dielectric plate and the cooling plate.

An electrostatic chuck comprising a dielectric plate according to the present invention, a cooling plate for heat dissipation of the dielectric plate, a connection film for coupling between the cooling plate and the dielectric plate, and a refractive plate coupled to an edge region of the dielectric plate. To provide.

Here, the upper edge region of the dielectric plate on which the wafer is held is refracted. In this case, ceramic is used as the dielectric plate, aluminum is used as the cooling plate, and indium is used as the connection film. In addition, a predetermined groove may be formed in the cooling plate positioned below the outermost region of the connection layer.

In addition, the edge of the surface where the dielectric plate and the cooling plate is coupled to provide an electrostatic chuck refracted.

Here, a predetermined groove may be formed in the inner edge region of the cooling plate due to the refraction, and the shape of the refraction may be at least one of a stepped step shape, a triangular pyramid shape, a pulse shape, and an uneven shape.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like numbers refer to like elements in the figures.

The technical principle of the electrostatic chuck according to the present invention will be briefly described.

2A and 2B are conceptual views for briefly explaining the technical principle of the electrostatic chuck according to the present invention.

Electrostatic chucks in the form of ceramic plates can be divided into high resistance, medium resistance and low resistance according to the degree of resistance between the DC electrode and the surface. In the case of high resistance, in order to clamp the wafer properly, the DC voltage should be relatively high and the distance between the electrode and the surface should be shorter than the low resistance. In this case, the low resistance is 10 ¹⁰ Ωcm to 10 ¹¹ Ωcm, and the high resistance is about 10 ¹⁴ Ωcm.

2A is a view for explaining the electrode aspect and the technical principle according to the case of low resistance, the inner electrode of the electrostatic chuck and the surface of the electrostatic chuck is separated by about 1 to 1.5mm. Therefore, when a predetermined voltage is applied to the electrode, a predetermined current is applied from the electrode plate and charged with a positive charge on the surface of the electrostatic chuck on which the wafer is held. In addition, the lower surface of the wafer is charged with negative charge and the upper surface is charged with positive charge by electromagnetic induction. Therefore, the electrostatic chuck grips the wafer through the electric force that interacts with the positive charge on the surface of the electrostatic chuck and the negative charge on the wafer surface.

In addition, FIG. 2B is a view for explaining the electrode aspect and the technical principle according to the case of high resistance, the inner electrode of the electrostatic chuck and the surface of the electrostatic chuck is separated by about 0.3 to 0.5mm. Therefore, when a predetermined voltage is applied to the electrode, the electrode plate is charged with a predetermined positive charge, and the lower surface of the wafer is charged with a negative charge. Thus, the electrostatic chuck grips the wafer through an electrical force that interacts with the positive charge on the electrode surface and the negative charge on the wafer surface.

An electrostatic chuck that adsorbs a wafer by using the above-described technical principle holds a wafer thereon, and includes a dielectric plate including internal electrodes, a cooling plate for dissipating heat from the dielectric plate, and a cooling plate and a dielectric plate. It includes a connection film that serves as a buffer for bonding, it characterized in that the refractive portion is formed in the edge region of the dielectric plate and the cooling plate. The refractive portion refers to giving a predetermined path difference to prevent damage of the connection film in the ceramic plate.

In this case, the refraction portion may be formed in one piece in which the shape between the cooling plate and the dielectric plate is changed. That is, the refraction portion may be formed by giving a refraction including stepped steps, protrusions or recesses of various shapes to the edge region of the surface where the dielectric plate and the cooling plate are bonded. In addition, a path difference may be provided by using a separate refractive plate having a predetermined step in the upper edge region of the dielectric plate on which the wafer is held and having a corresponding step. As such, given a predetermined path difference within the ceramic plate, F radicals may be recombined to minimize damage to the connection film.

Ceramic is used as the dielectric plate, aluminum is used as the cooling plate, and indium is used as the connection film. In addition, a ceramic is used as the refractive plate.

Hereinafter, an electrostatic chuck including a protection part for protecting the connection film through a predetermined refraction and a protection part for protecting the connection film through a separate refraction plate will be described in detail with reference to the drawings.

3A is a cross-sectional view of an electrostatic chuck according to a first embodiment of the present invention, and FIG. 3B is a conceptual diagram of separation of the electrostatic chuck according to the first embodiment of the present invention. 3C to 3E are conceptual views illustrating a deformable example of the region A of FIG. 3A.

3A to 3E, the electrostatic chuck according to the first embodiment of the present invention includes a ceramic plate 110, a ceramic plate 110 having a predetermined refraction portion formed at an edge thereof, and having an electrode 112 embedded therein. And a cooling plate 120 having a corresponding refractive portion, and an indium film 130 for bonding the cooling plate 120 and the ceramic plate 110 to each other.

In addition, the cooling plate 120 may further include a groove 140 formed in the inner edge region of the refracting portion. The apparatus may further include a cooling unit (not shown) that performs temperature control and cooling of the wafer. In addition, a plurality of lift pins (not shown) may be further included to facilitate loading and unloading of the wafer. The cooling unit may be formed in the form of a plurality of tubes through which the coolant or cooling helium gas is introduced and discharged, and may be formed through the cooling plate 120 and the ceramic plate 110. In addition, the lift pin may also be formed through the cooling plate 120 and the ceramic plate 110. In addition, the electrode 112 may further include an RF voltage path (not shown) capable of applying an RF voltage.

The ceramic plate 110 fixes the wafer through the aforementioned technical principle. That is, a predetermined channel may be formed on the surface of the ceramic plate 110, or a channel may be formed on the electrode 112 inside the ceramic plate 110. The ceramic plate 110 may have various sizes and shapes according to the size and shape of the wafer. In this embodiment, it is preferable to form a 200mm or 300mm wafer to hold a size. That is, it can be formed equal to or larger than the size of the wafer.

The cooling plate 120 may be manufactured using a material capable of dissipating heat from the ceramic plate 110 to the outside. In this embodiment, it is preferable to manufacture the cooling plate 120 using aluminum as its main component.

In the present invention, a predetermined path for preventing damage to the indium film 130 that bonds the ceramic plate 110 and the cooling plate 120 by the plasma generated inside the chamber (especially NF ₃ generated during the cleaning process). In the present embodiment, the indium film 130 is damaged by giving a step (see region A in FIG. 3A) by a predetermined refraction in the edge region of the surface where the ceramic plate 110 and the cooling plate 120 contact each other. Can be prevented.

Therefore, the ceramic plate 110 having the step is manufactured in a shape where the edge region is recessed and the central region is protruded. That is, the ceramic plate 120 has a shape where both edges are recessed when viewed in its cross section as shown in FIG. 3A, but the center region of the circular plate protrudes as shown in FIG. 3B.

The step of the ceramic plate 110 may be formed to have a single refractive surface (surface connecting the upper and lower surfaces) as shown in FIGS. 3A to 3C. That is, as shown in FIG. 3A, the refractive surface may have a vertical shape, and as shown in FIG. 3C, the refractive surface may have a predetermined slope. In addition, the above-described refractive portion may be a step shape having a plurality of steps.

The thickness of the recessed region of the ceramic plate 110 (T1 in FIG. 3A) is preferably about 1 to 70% of the total thickness of the ceramic plate, and the width of the recessed region (L1 in FIG. 3A) is the entire ceramic plate. It is preferable that it is about 0.1 to 10% of the width which (110) has. When the width of the ceramic plate 110 is larger than the above-described range, the coupling between the ceramic plate 110 and the cooling plate 120 is not easy, and heat transfer may not be effective. The external surface of 110 may be easily damaged. In addition, when the O-ring is mounted, a predetermined groove (Groove) must be formed to process it and at least 5 mm of edge space is required. However, in the present invention, the outer space can be reduced to 5 mm or less, thereby making the bonding area wider.

Meanwhile, the cooling plate 120 is formed to correspond to the ceramic plate 110. That is, the edge region protrudes, and the center region is produced in a recessed shape. This is because not only the adhesion between the two plates can be facilitated, but also the heat transfer area can be widened, and the damage of the indium film 130 which bonds the two plates by external elements can be prevented. In addition, in order to prevent breakage of the indium film 130 that may occur when the ceramic plate 110 and the cooling plate 120 are bonded using indium, an inner edge area of the cooling plate 120 (ie, A predetermined groove 140 may be further formed on the outer surface of the surface.

The above-described groove 140 may be formed in a trench shape along the outermost periphery of the recessed surface, may be formed in the form of a plurality of holes as well as in the form of a lattice. That is, the groove 140 is to compensate for the surface area is reduced when the indium of the liquid is fixed, the depth and thickness of the groove 140 may be changed according to the above reason. In addition, it is effective that the groove 140 has a predetermined slope to compensate for the reduction in surface area. It is effective that the inclination is about 100 to 170 ° based on the surface of the lower recessed surface. If the inclination of the groove 140 is less than the above-described range, it is difficult to receive compensation due to the reduction of the surface area through the indium introduced into the groove 140, and if it is larger than this, the protrusion of the cooling plate 120 may be damaged. This is because the indium is not easily introduced into the groove 140 and thus loses the purpose of the present application of forming the groove 140.                     

In addition, the above-described refractive portion may be formed in various forms as well as steps.

As shown in FIG. 3D, the ceramic plate 110 of the present invention has a recessed area in the shape of a triangular pyramid. Meanwhile, the cooling plate 120 has a triangular pyramid-shaped protruding region at its edge to correspond thereto. In addition, as shown in FIG. 3E, the ceramic plate 110 has a recessed region at the edge thereof, and the cooling plate 120 has a pulse-shaped protruding region at the edge thereof so as to correspond thereto. The trench may be formed to have a predetermined slop as well as a right angle shape. This can prevent the invasive plasma from penetrating the inside.

The manufacture of the ceramic plate 110 and the cooling plate 120 in the first embodiment may be formed by using a mold having the refraction of the above-described structure, and after the cylindrical plate is manufactured, it is formed through mechanical processing. You may. In addition, it may be formed by combining a plurality of cylindrical plates of which the edge region is changed.

As shown in FIG. 3, a predetermined step of a recessed shape is formed at the edge of the ceramic plate 110, and a predetermined step of protruding shape may be formed at the edge of the cooling plate 120 to correspond thereto. The opposite is also possible.

4 is a cross-sectional view of the electrostatic chuck with the opposite step of FIG. 3A.

Referring to FIG. 4, in the present embodiment, the electrostatic chuck includes a ceramic plate 110 having an electrode 112 embedded therein and a predetermined refractive portion formed at an edge region thereof, and a cooling plate having a refractive portion corresponding to the ceramic plate 110. 120 and an indium film 130 for adhering the cooling plate 120 and the ceramic plate 110 to each other.                     

In the above, a step of a protruding shape is formed at the edge of the ceramic plate 110, and a terminal of a recessed shape is formed at the edge of the cooling plate 120 to correspond thereto. In this case, the recess region is effectively recessed within a range in which the electrode 112 inside the ceramic plate 110 is not damaged. In addition, the region recessed in the lower portion of the ceramic plate preferably has the same diameter as the diameter of the wafer held on the ceramic plate 110. The shape of the refraction portion may be various shapes including stepped steps, triangular pyramids, pulses, and the like.

In the present invention, a predetermined path difference is prevented in order to prevent damage to the indium film 130 which bonds the ceramic plate 110 and the cooling plate 120 by the plasma generated inside the chamber (especially, NF ₃ generated during the cleaning process). However, in the present exemplary embodiment, damage to the indium layer 130 may be prevented by giving a step due to a predetermined refraction in the edge region of the surface where the ceramic plate 110 and the cooling plate 120 contact each other.

In addition, the outer space (refer to T1 in FIG. 4) can be reduced to 0.1 mm to 5 mm or less than the conventional O-ring, thereby making the bonding area wider, and eliminating the gap between the contact surfaces due to the O-ring. The contact between the ceramic plate 110 and the cooling plate 120 may be better.

Briefly looking at the manufacturing method of the above-described electrostatic chuck as follows.

In the manufacturing of the electrostatic chuck according to the first embodiment, the ceramic plate 110 having a predetermined step at both edges and the cooling plate 130 having the step corresponding to the step are manufactured by the aforementioned method. do. Indium is applied to the liquid phase at the interface between the ceramic plate 110 and the cooling plate 130. The fixing process is performed to fix the liquid indium to bond the ceramic plate 110 and the cooling plate 130 to each other. It is effective to minimize the difference in temperature in the ceramic plate 110 by allowing the front surface to be bonded between the ceramic plate 110 and the cooling plate 120. In this embodiment, indium may be applied to the lower surface of the recessed region of the cooling plate 110 to strengthen the coupling between the ceramic plate 110 and the cooling plate 120. In addition, since the indium expands at a high temperature and contracts at a low temperature, the groove 140 may be formed in the lower predetermined region of the cooling plate 120 to compensate for a phenomenon that the surface area of the indium is reduced during the fixing process. In addition, the formation of the grooves 140 may prevent a phenomenon in which indium flows back when the two plates are bonded.

As mentioned above, in the first embodiment, the refraction portion is given to the edge of the ceramic plate and the path difference in which the plasma is introduced by giving the refraction portion to the cooling plate is correspondingly provided. Can be.

5A to 5C are cross-sectional views of an electrostatic chuck according to a second embodiment of the present invention.

5A to 5C, the electrostatic chuck according to the second embodiment of the present invention includes a ceramic plate 110 having an electrode 112 embedded therein and a predetermined step formed in an edge region thereof, and the ceramic plate 150. The ceramic plate 120 has a step corresponding to the step between the cooling plate 120, the indium film 130 and the ceramic plate 110 to bond the cooling plate 120 and the ceramic plate 110 It includes a refracting plate 150 mounted to the cooling plate 120.

The apparatus may further include a cooling unit (not shown) that performs temperature control and cooling of the wafer. In addition, a plurality of lift pins (not shown) may be further included to facilitate loading and unloading of the wafer. The plurality of pipes and lift pins constituting the cooling unit may be formed through the ceramic plate and the cooling plate. In addition, the electrode 112 may further include an RF voltage path for applying an RF voltage.

The coupling of the cooling plate 120 and the ceramic plate 110 uses the indium film 130, because indium can enhance the bond between dissimilar metals, and both materials can facilitate heat transfer. However, indium has a problem of being easily damaged by NF ₃ .

Therefore, in the present embodiment, the edge portion of the electrostatic chuck may be covered by the refracting plate to prevent the penetration of NF ₃ to cause recombination of F radicals. Further, the refractive plate 150 is mounted at the edge of the electrostatic chuck without changing the size of the electrostatic chuck, and recessed in a part of the edge region of the ceramic plate 110 and / or the cooling plate 120 to give a predetermined path difference. The refractive step by is formed. That is, the refracting plate 150 is manufactured in a '-' shape and mounted to be connected to the upper surface of the ceramic plate 110 and the sidewall surfaces of the ceramic plate 110 and the cooling plate 120.

Thus, the indium film can be sufficiently protected without using an O-ring for protecting the indium film between the ceramic plate 110 and the cooling plate 120. As a result, problems such as the lifting of the adhesive surface caused by the introduction of the O-ring and the increase in the width of the edge region can be prevented.

The ceramic plate 110 may have various sizes and shapes according to the size and shape of the wafer. In this embodiment, it is preferable to produce a size and disc shape capable of holding a 200 mm or 300 mm wafer. The ceramic plate 110 of the present embodiment has a step that is refracted due to the protruding central region. Here, the wafer is positioned above the protruding center region. That is, the shape of the present embodiment may be manufactured as the shape inverting the ceramic plate of Figure 3b. In this case, the refractive surface may have a vertical shape or may have a predetermined slope. In addition to this, the above-described step may be a step shape having a plurality of refractive surfaces. In addition, a predetermined region of the edge (outer peripheral surface) of the cooling plate 120 is also recessed so that a part of the refracting plate is located.

The above-described manufacturing of the ceramic plate 110 may be formed by using a mold having the above-described shape. After manufacturing the cylindrical ceramic plate 110, the edge of the ceramic plate 110 may be processed through a predetermined processing process. The region may be formed by removing the region, or may be formed by combining the first ceramic plate and the second ceramic plate having a smaller diameter than the first ceramic plate.

The cooling plate 120 may be manufactured using a material capable of dissipating heat from the ceramic plate 110 to the outside. In this embodiment, it is preferable to manufacture the cooling plate 120 using aluminum as its main component. In addition, the size of the cooling plate 120 is larger than that of the ceramic plate 110. That is, it is most preferable to form the cooling plate 120 in the same size as the sum of the ceramic plate 110 and the refracting plate 150 mounted on the side surface thereof.

The refracting plate 150 is manufactured in the form of a circular ring and is formed to have a step corresponding to the step of the ceramic plate 110. The refraction plate 150 may be attached to the edge of the ceramic plate 110 to provide a path difference to the intrusion path of the external plasma. Thereby, damage of indium by F radical can be minimized. The refracting plate 150 is formed of one plate without a gap.

In addition, by providing a predetermined step in the upper edge region of the cooling plate 120, the refracting plate 150 is mounted in the step region of the ceramic plate 110 and the cooling plate 120, thereby providing a cooling plate 120 and The bonding surface between the ceramic plates 110, that is, the indium film 130 may be effectively protected from an external plasma.

This forms a stepped step over the ceramic plate 110 and the cooling plate 120 as shown in FIG. 5B, and mounts the refracting plate 150 corresponding to the step. That is, at least one step may be formed in both the ceramic plate 110 and the cooling plate 120. The surface where the ceramic plate 110 and the cooling plate 120 are bonded may be the same, or the cooling plate 120 may be wider than the ceramic plate 110. In addition, a predetermined groove may be formed in the cooling plate 120 positioned below the outermost region of the indium film 130 for bonding the ceramic plate 110 and the cooling plate 120 to each other. Such grooves have a structure as described in the first embodiment, and the formation of the grooves can prevent the phenomenon that the surface area of indium is reduced during the fixing process of the indium film.

In addition, as shown in FIG. 5C, damage to the indium film 130 is caused by a strong plasma generated during the cleaning process, and a refractive plate having a predetermined refractive portion at an edge of the upper ceramic plate 110 and having a corresponding refractive portion is provided. By mounting the upper portion of the ceramic plate 110 using the 150, the indium film 130 may be secured. That is, the 'b' shaped refraction portion is formed at the edge of the ceramic plate 110, and the refractive plate 150 is formed in the 'a' shape so as to correspond thereto. As a result, the lower indium film 130 may be protected from the plasma through adhesion of the ceramic plate 110 and the refractive plate 150. In addition, by forming a predetermined groove, it is possible to prevent the phenomenon that the surface area of indium is reduced during the fixing step.

Briefly looking at the manufacturing method of the electrostatic chuck according to the second embodiment described above.

First, the ceramic plate 110 having a predetermined step in the upper edge region is bonded onto the cooling plate 120 using liquid indium. That is, the liquid indium is coated on the cooling plate 120, and then the ceramic plate 110 is mounted thereon, and then the liquid indium is fixed to bond the ceramic plate 110 and the cooling plate 120 to each other. . At this time, the front surface of the ceramic plate 110 is bonded to minimize the difference in temperature in the ceramic plate 110. Since liquid indium may reduce its surface area when it is fixed, it is effective to apply a sufficient amount to the surface of the cooling plate 120.

The refracting plate 150 is mounted on the sidewall of the ceramic plate 110 having a step. As a result, only the upper surface of the ceramic plate 110 is exposed and the side surface of the ceramic plate 110 is protected by the refractive plate 150. In addition, F radicals may be recombined through a predetermined step formed in the ceramic plate 110, thereby minimizing damage to the indium film 130 due to F radicals.

As described above, the present invention can prevent the damage of the indium film by an external plasma by giving a predetermined path difference to the edge of the indium film bonding the ceramic plate and the cooling plate of the electrostatic chuck.

In addition, due to the indium film and the cooling plate to release the heat of the ceramic plate can reduce the thermal stress received by the ceramic plate.

In addition, a refractive portion is provided at the edge of the region where the ceramic plate and the cooling plate are coupled, and a predetermined groove is formed in the lower part of the step of the cooling plate to minimize the difference in temperature in the ceramic plate, and the liquid indium surface area when the indium is fixed It can compensate for the shrinkage and prevent backflow of indium when bonding two plates.

In addition, the contact can be improved by removing the O-ring to eliminate the gap between the connecting surfaces due to the O-ring.

In addition, by removing the O-ring and placing the refractive portion in the edge region, the outer space of the ceramic plate and the cooling plate can be reduced to 5 mm or less, thereby making the bonding area wider.

In addition, by attaching the refracting plate in the outer circumferential surface area on the ceramic plate, it is possible to give a path difference to the intrusion path of the plasma and to protect the ceramic plate.

Claims (7)

Dielectric plates; A cooling plate for heat dissipation of the dielectric plate; A connection film for coupling between the cooling plate and the dielectric plate; And An electrostatic chuck comprising a refracting plate that couples to an edge region of the dielectric plate. The method of claim 1, An electrostatic chuck in which the upper edge region of the dielectric plate on which the wafer is held is refracted. The method according to claim 1 or 2, An electrostatic chuck using ceramic as the dielectric plate, aluminum as the cooling plate, and indium as the connection film. The method of claim 1, An electrostatic chuck having a predetermined groove formed in the cooling plate positioned below the outermost region of the connection film. Electrostatic chuck with the refraction of the edge region of the surface where the dielectric plate and cooling plate join. The method of claim 5, The electrostatic chuck has a predetermined groove formed in the inner edge region of the cooling plate due to the deflection. The method of claim 5, The shape of the refraction is at least one of stepped stepped shape, triangular pyramid shape, pulse shape and irregularities shape.

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