Esc with spacers and method of attaching esc

Abstract

The present invention relates to an electrostatic chuck with a spacer attached and a method for attaching the electrostatic chuck. More specifically, the invention relates to an electrostatic chuck with a spacer attached and a method for attaching the electrostatic chuck, characterized by using a ring-shaped spacer to prevent the adhesive from flowing into the ventilation hole during the process of applying an adhesive to attach a ceramic sheet to the upper surface of the electrostatic chuck. According to the present invention, by using a spacer with a hole in the center to block the area around the ventilation hole, the inflow of adhesive can be prevented, and since a drilling process is not required, the time and cost of the electrostatic chuck manufacturing process are reduced.

Description

Technology Field

[0001] The present invention relates to an electrostatic chuck with a spacer attached and a method for attaching the electrostatic chuck. More specifically, the invention relates to an electrostatic chuck with a spacer attached and a method for attaching the electrostatic chuck, characterized by using a ring-shaped spacer to prevent the adhesive from flowing into the ventilation hole during the process of applying an adhesive to attach a ceramic sheet to the upper surface of the electrostatic chuck. Background Technology

[0002] Generally, semiconductor devices can be manufactured by sequentially or repeatedly performing numerous processes such as sputtering, photolithography, etching, ion implantation, and chemical vapor deposition on a wafer placed in a chamber.

[0003] In the manufacturing process of such semiconductor devices, it is important that the wafer is tightly secured within the chamber to maintain uniform thin film characteristics.

[0004] There are mechanical chuck and electrostatic chuck (ESC) methods for fixing wafers; however, the electrostatic chuck method is widely used because it generates even attractive or repulsive forces across the entire contact surface with the wafer to ensure surface flatness and allows for effective temperature control by ensuring close contact between the wafer and the contact surface.

[0005] FIG. 1 is a perspective view showing the structure of a general type of electrostatic chuck, and FIG. 2 is an exploded perspective view showing the structure of a body and a ceramic sheet.

[0006] The electrostatic chuck (100) is composed of a body made of a metal such as aluminum and a plate made of a ceramic material attached to the upper surface of the body. As shown in FIG. 1, the body is composed of a lower body (102) and an upper body (104) that extends from the upper part of the lower body (102). Typically, in a flat cylindrical body, the diameter of the upper body (104) is smaller than the diameter of the lower body (102). However, the shape or size of the body may vary depending on the device.

[0007] The ceramic sheet (106) attached to the upper surface of the upper body (104) is made of a material capable of generating electrostatic force.

[0008] A plurality of pinholes (108, 112) and ventilation holes (110, 114) are formed in the lower body (102), the upper body (104), and the ceramic sheet (106). The pinholes (108) and ventilation holes (110) formed in the upper body (104) are formed at positions corresponding to the pinholes (112) and ventilation holes (114) formed in the ceramic sheet (106). Additionally, while it is common for the sizes of adjacent holes above and below to be the same, their sizes may differ.

[0009] Pins that push the wafer with physical force can enter and exit through the pinholes (108, 112). Helium (He) flows through the ventilation holes (110, 114). Therefore, it is necessary to ensure that the pinholes (108, 112) and ventilation holes (110, 114) are not blocked by adhesive or film.

[0010] FIG. 3 is a conceptual diagram showing a method of attaching a ceramic sheet to the upper surface of a body, and FIG. 4 is a cross-sectional view showing a first spacer blocking a ventilation hole being drilled.

[0011] Generally, the ceramic sheet (106) and the upper body (104) are attached using an adhesive. At this time, a liquid adhesive is applied to the upper surface of the upper body (104), and then the ceramic sheet (106) is placed on top of it to attach it. During the adhesive application process, the liquid adhesive must not enter the interior of the ventilation hole (110) of the upper body (104).

[0012] To do this, a first spacer (116) in the form of a sticker is first attached to the ventilation hole (110) of the upper body (104). The first spacer (116) is generally a circular sticker, but its shape may vary. Due to the attachment of the first spacer (116), the adhesive does not enter the interior of the ventilation hole (110), but if the first spacer (116) is left as is, the flow of helium becomes impossible.

[0013] So, as shown in FIG. 4, after the attachment of the ceramic sheet (106) is finished, a perforating device (120) is inserted through the ventilation hole (110) to pierce the center of the first spacer (116). Helium can move through the first spacer (116) pierced by the perforating device (120).

[0014] However, when the ceramic sheet (106) is attached using this process, a burr generated during the drilling process remains in the center of the first spacer (116), which may hinder the movement of helium. In addition, since the process of drilling the first spacer (116) must be performed by inserting the drilling device (120) through each ventilation hole (110), there was a problem of taking a long time and incurring costs. Prior art literature

[0015] (Patent Document 0001) KR 10-2418014 B1 The problem to be solved

[0016] The present invention, aimed at solving the aforementioned problems, provides an electrostatic chuck with a spacer attached and a method for attaching the electrostatic chuck, wherein a second spacer in the form of a ring with a hole in the center is attached to a ventilation hole before applying adhesive to the upper surface of an upper body, and adhesive is injected through the gap after covering with a ceramic sheet, thereby preventing liquid adhesive from entering the ventilation hole while allowing the bonding process to proceed. means of solving the problem

[0017] The present invention, devised to solve the aforementioned problems, is an electrostatic chuck for fixing a semiconductor wafer, comprising: a lower body (102); an upper body (104) extending from the upper portion of the lower body (102) and having a plurality of pinholes (108) and a plurality of ventilation holes (110); a ceramic sheet (106) attached to the upper surface of the upper body (104) to generate electrostatic force, having a plurality of pinholes (112) and a plurality of ventilation holes (114) formed at positions corresponding to the pinholes (108) and ventilation holes (110) formed in the upper body (104); and an adhesive layer (126) formed between the upper surface of the upper body (104) and the lower surface of the ceramic sheet (106) to bond the upper body (104) and the ceramic sheet (106). It includes a second spacer (122) attached to a position corresponding to the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106) on the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106); wherein the second spacer (122) is in the shape of a ring with an opening formed in the center.

[0018] The opening of the second spacer (122) may be circular, and the diameter of the opening is relatively larger than or equal to the diameter of the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106).

[0019] The second spacer (122) is attached between the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106), and is characterized by preventing liquid adhesive from flowing into the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106).

[0020] The adhesive layer (126) is characterized by being formed by introducing a liquid adhesive through an open space formed on the side of the surface where the upper body (104) and the ceramic sheet (106) meet.

[0021] The adhesive layer (126) is characterized by being formed by liquid adhesive introduced through the pinhole (108) of the upper body (104) and introduced between the upper surface of the upper body (104) and the lower surface of the ceramic sheet (106).

[0022] According to another embodiment, the present invention comprises a method for attaching a ceramic sheet of an electrostatic chuck for fixing a semiconductor wafer, the method comprising: a step of attaching a second spacer (122) at a position corresponding to a ventilation hole (110) of the upper body (104) and a ventilation hole (114) of the ceramic sheet (106) on the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106); a step of attaching the lower surface of the ceramic sheet (106) to the upper surface of the upper body (104), and then flipping the ceramic sheet (106) so that it faces downward and placing it in an adhesive container (206) installed on the inner bottom of a chamber (202); a step of introducing a liquid adhesive into the adhesive container (206) so that the adhesive flows into the space between the upper body (104) and the ceramic sheet (106); and a step of making the air pressure inside the chamber (202) into a vacuum state.

[0023] According to another embodiment, the present invention is a method for attaching a ceramic sheet of an electrostatic chuck for fixing a semiconductor wafer, comprising the steps of: attaching a second spacer (122) at a position corresponding to the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106) on the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106); attaching the lower surface of the ceramic sheet (106) to the upper surface of the upper body (104), and then flipping the ceramic sheet (106) so that it faces downward and placing it in an adhesive container (206) installed on the inner bottom of a chamber (202); and injecting a liquid adhesive through a pinhole (108) formed in the upper body (104) using an adhesive injector (208) so that the adhesive flows into the space between the upper body (104) and the ceramic sheet (106). It includes the step of making the air pressure inside the chamber (202) into a vacuum state. Effects of the invention

[0024] According to the present invention, by using a spacer with a hole in the center to block the area around the ventilation hole, the inflow of adhesive can be prevented, and since a drilling process is not required, the time and cost of the electrostatic chuck manufacturing process are reduced. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view showing the structure of a general type of electrostatic chuck. FIG. 2 is an exploded perspective view showing the structure of the body and the ceramic sheet. FIG. 3 is a conceptual diagram showing a method of attaching a ceramic sheet to the upper surface of a body. FIG. 4 is a cross-sectional view showing the first spacer blocking the ventilation hole being pierced. FIG. 5 is a conceptual diagram showing an attachment method according to an embodiment of the present invention. FIG. 6 is a perspective view showing the second spacer attached to the upper surface of the upper body. FIG. 7 is a cross-sectional view showing the state of infiltrating adhesive between an upper body with a second spacer attached and a ceramic sheet. FIG. 8 is a conceptual diagram showing a method of penetrating an adhesive according to a first embodiment. FIG. 9 is a conceptual diagram illustrating a method of penetrating an adhesive according to a second embodiment. Specific details for implementing the invention

[0026] Hereinafter, "an electrostatic chuck with a spacer attached and a method for attaching an electrostatic chuck" according to an embodiment of the present invention will be described with reference to the drawings.

[0027] FIG. 5 is a conceptual diagram showing an attachment method according to an embodiment of the present invention, FIG. 6 is a perspective view showing a state in which a second spacer is attached to the upper surface of an upper body, and FIG. 7 is a cross-sectional view showing a state in which an adhesive is infiltrated between an upper body with a second spacer attached and a ceramic sheet.

[0028] The electrostatic chuck (100) of the present invention has a structure identical to a conventional structure, and an upper body (104) with a small diameter is formed on top of a lower body (102) at the bottom, and a plurality of pin holes (108) and ventilation holes (110) are formed penetrating in the vertical direction in the upper body (104) and the lower body (102). In addition, pin holes (112) and ventilation holes (114) are formed at the same locations in a ceramic sheet (106) attached to the upper surface of the upper body (104) so ​​that helium and pins can pass through.

[0029] The structure and material of the upper body (104), lower body (102), and ceramic sheet (106) are the same as those of the electrostatic chuck (100) in the prior art.

[0030] An adhesive is applied to the upper surface of the upper body (104) to attach a ceramic sheet (106), and after attachment, an adhesive layer (126) is formed between the upper body (104) and the ceramic sheet (106) so that the upper body (104) and the ceramic sheet (106) can be joined.

[0031] Before applying adhesive to the upper body (104), the second spacer (122) is first attached to the ventilation hole (110). The second spacer (122) can be a ring-shaped sticker with a hole in the center. Various materials such as paper, vinyl film, aluminum foil, and plastic sheet can be used for the second spacer (122). Since the second spacer (122) does not require a perforation process, it is acceptable to use a material that is not easily perforated. However, it is preferable to use a material with low absorbency so that the adhesive does not penetrate and flow into the ventilation hole (110).

[0032] The second spacer (122) includes an opening with a diameter of R1 in the center of a circle with a diameter of R2. The opening generally has a size corresponding to the ventilation hole (110). The diameter of the opening of the second spacer (122) may be smaller than the diameter of the ventilation hole (110), but it is preferable to form it equal to or larger than the diameter of the ventilation hole (110) to facilitate the flow of helium.

[0033] In the present invention, the shape of the second spacer (122) is described as being in the shape of a ring, but it may be manufactured in a square or other shape as long as it can form a structure that blocks the surroundings of the ventilation hole (110).

[0034] The second spacer (122) can be manufactured in the form of a single-sided or double-sided sticker. The second spacer (122) can be attached to the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106). Regardless of where it is attached, it is preferable to attach it at the same location as the ventilation holes (110, 114). It is preferable to manufacture the second spacer (122) as a double-sided sticker so that it can be attached simultaneously to the upper surface of the upper body (104) and the lower surface of the ceramic sheet (106).

[0035] Additionally, since the second spacer (122) must form a barrier to prevent adhesive injected from the side from flowing into the ventilation holes (110, 114) while ensuring that the ventilation holes (110) of the upper body (104) and the ventilation holes (114) of the ceramic sheet (106) communicate with each other when the upper body (104) and the ceramic sheet (106) are in contact, it is preferable to manufacture it in a shape having a thickness greater than a certain size. Due to the second spacer (122) placed between the upper body (104) and the ceramic sheet (106), a small space is formed between the upper body (104) and the ceramic sheet (106), and the adhesive that penetrates into this space can form an adhesive layer (126) after curing.

[0036] If necessary, a filter (124) may be inserted into the ventilation hole (110), but depending on the model of the electrostatic chuck, the filter (124) may not be used. The filter (124) inserted into the ventilation hole (110) is a porous filter made of a porous material and is used to control the flow rate of gas while ensuring the movement of gaseous helium during the semiconductor wafer processing process. Since the ventilation performance of the filter (124) must be maintained, it must be sealed so that adhesive does not penetrate during the attachment process of the ceramic sheet (106).

[0037] The electrostatic chuck (100) of the present invention is characterized by using a ring-shaped second spacer (122) with a central opening formed therein so that adhesive does not flow into the ventilation holes (110, 114) during the process of attaching the upper body (104) and the ceramic sheet (106).

[0038] With the second spacer (122) attached to a position corresponding to the ventilation holes (110, 114) on the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106), the upper body (104) and the ceramic sheet (106) are brought into close contact. A space of the same height as the thickness of the second spacer (122) is created between the upper surface of the upper body (104) and the lower surface of the ceramic sheet (106). In this state, if adhesive is injected through the side or through the pinhole (108), the adhesive can flow into the space where the adhesive layer (126) is to be formed. After removing air bubbles from the adhesive and uniformly dispersing the adhesive inside the vacuum chamber and then curing it, the attachment of the ceramic sheet (106) is completed.

[0039] As illustrated in FIG. 7, an adhesive layer (126) is formed between the upper body (104) and the ceramic sheet (106). When the adhesive flows into the space between the upper surface of the upper body (104) and the lower surface of the ceramic sheet (106), it comes into contact with the outer edge of the ring-shaped second spacer (122). Since the liquid adhesive is prevented from flowing further by the second spacer (122), it cannot enter the interior of the ventilation holes (110, 114) that are in communication with the inner opening of the ring.

[0040] Therefore, the attachment process can be completed without a separate process of perforating the second spacer (122) after the attachment process, while preventing the inflow of adhesive.

[0041] FIG. 8 is a conceptual diagram showing a method of infiltrating an adhesive according to a first embodiment, and FIG. 9 is a conceptual diagram showing a method of infiltrating an adhesive according to a second embodiment.

[0042] To uniformly inject adhesive into the space, an attachment device (200) of the structure shown in FIGS. 8 and 9 can be used.

[0043] The attachment method according to the first embodiment illustrated in FIG. 8 is characterized by introducing an adhesive from the side of the electrostatic chuck (100).

[0044] After attaching a second spacer (122) between the upper body (104) and the ceramic sheet (106), adhesive injection and dispersion are carried out inside a vacuum chamber (202).

[0045] A jig (204) is installed on the inner bottom of a vacuum chamber (202). An adhesive container (206) is placed on top of the jig (204). The adhesive container (206) may be structured to hold a certain amount of adhesive. The adhesive container (206) may be made of various materials such as aluminum foil, a metal tray, or a ceramic container. Additionally, it is desirable to have a depth sufficient to hold a larger amount than the amount of adhesive.

[0046] For the attachment process of the electrostatic chuck (100), the ceramic sheet (106) is flipped over so that it faces downward and placed in the adhesive container (206). The upper surface of the ceramic sheet (106) is in close contact with the bottom surface of the adhesive container (206), and the side of the surface where the upper body (104) and the ceramic sheet (106) meet is left open.

[0047] In this state, liquid adhesive is poured into the adhesive container (206). The poured adhesive flows into the space between the upper body (104) and the ceramic sheet (106). Since the upper surface of the ceramic sheet (106) is in close contact with the bottom surface of the adhesive container (206), the adhesive cannot spread to the upper surface of the ceramic sheet (106). Therefore, the adhesive cannot enter the ventilation hole (114) formed in the ceramic sheet (106).

[0048] If necessary, the entire upper surface of the ceramic sheet (106) may be masked with adhesive tape so that the adhesive does not enter the interior of the ventilation hole (114).

[0049] The adhesive enters the space between the upper body (104) and the ceramic sheet (106), and some of it flows into the pinhole (108) formed in the upper body (104).

[0050] In this state, if the air pressure inside the chamber (202) is made into a vacuum, the adhesive enters along the pinhole (108) and enters the interior of the upper body (104) and the lower body (102). Additionally, as the adhesive flows in the vacuum state, the air remaining inside the adhesive is expelled, allowing the adhesive to be uniformly dispersed.

[0051] When the adhesive is sufficiently introduced and maintained for a certain period of time, or when the electrostatic chuck (100) is moved into the chamber (202) to dry, the adhesive hardens and the attachment of the upper body (104) and the ceramic sheet (106) is completed.

[0052] In the first embodiment, the adhesive is introduced through the side of the electrostatic chuck (100) and is introduced into the interior of the body through the pinhole (108).

[0053] Meanwhile, the attachment method according to the second embodiment illustrated in FIG. 9 is characterized by introducing an adhesive inside the electrostatic chuck (100).

[0054] The electrostatic chuck (100) is placed in the adhesive container (206) inside the chamber (202) in the same manner as in the first embodiment.

[0055] In this state, liquid adhesive is injected through the pinhole (108) formed in the upper body (104) and the lower body (102). Since the electrostatic chuck (100) is in a flipped state with the ceramic sheet (106) facing downward, adhesive will be injected into the interior of the pinhole (108) from the bottom surface of the lower body (102). The adhesive can be injected through an adhesive injector (208) in the form of a nozzle.

[0056] The injected adhesive reaches the space between the upper body (104) and the ceramic sheet (106) and spreads to the sides to fill the space. If the adhesive is continuously injected, it can exit through the side space of the electrostatic chuck (100).

[0057] Even at this time, the adhesive cannot enter the interior of the ventilation hole (110) due to the blocking action of the second spacer (122). In addition, since the upper surface of the ceramic sheet (106) is in close contact with the bottom surface of the adhesive container (206), the adhesive cannot flow into the ventilation hole (114) formed in the ceramic sheet (106).

[0058] After sufficient adhesive has been injected, the inside of the chamber (202) is made into a vacuum. As before, air bubbles inside the adhesive are expelled, allowing the adhesive to be uniformly dispersed.

[0059] Then, the bonding process of the upper body (104) and the ceramic sheet (106) is completed by going through the curing process of the adhesive in the same way.

[0060] The ceramic sheet (106) can be easily attached using the structure and method described above, and since the drilling work after the attachment process is eliminated, the time and cost of the process are reduced.

[0061] Although preferred embodiments of the present invention have been described above with reference to the attached drawings, it will be understood by those skilled in the art that the technical configuration of the present invention described above may be implemented in other specific forms without altering the technical concept or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive, and the scope of the present invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention. Explanation of the symbols

[0062] 100 : Electrostatic chuck 102 : Lower body 104 : Upper body 106 : Ceramic sheet 108, 112: Pinholes 110, 114: Ventilation holes 116: First spacer 118, 126: Adhesive layer 120 : Drilling device 122 : Second spacer 124 : Filter 200 : Attachment device 202: Chamber 204: Jig 206 : Adhesive container 208 : Adhesive injector

Claims

Claim 1 delete Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 A method for attaching a ceramic sheet of an electrostatic chuck that fixes a semiconductor wafer, comprising the steps of: attaching a second spacer (122) at a position corresponding to the ventilation hole (110) of the upper body (104) and the ventilation hole (114) of the ceramic sheet (106) on the upper surface of the upper body (104) or the lower surface of the ceramic sheet (106); attaching the lower surface of the ceramic sheet (106) to the upper surface of the upper body (104), and then flipping the ceramic sheet (106) so that it faces downward and placing it in an adhesive container (206) installed on the inner bottom of the chamber (202); introducing a liquid adhesive into the adhesive container (206) so that the adhesive flows into the space between the upper body (104) and the ceramic sheet (106) and into the pinhole (108) formed in the upper body (104); and creating a vacuum state in the air pressure inside the chamber (202) so that the adhesive A method for attaching a ceramic sheet of an electrostatic chuck, comprising the step of entering the interior of the upper body (104) and the lower body (102) while following the pinhole (108). Claim 7 delete

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