Chuck table for wafer grinding apparatus

Abstract

The embodiment relates to a chuck table for a wafer grinding device that uniformly transmits indirect vacuum pressure across the entire surface of a wafer. According to one aspect of an embodiment, a chuck table for a wafer grinding device is provided, comprising: a hollow portion on which a wafer is placed; a body portion on which the hollow portion is placed; and a vacuum channel provided inside the body portion and including a channel connected to the side of the hollow portion.

Description

Technology Field

[0001] The embodiment relates to a chuck table for a wafer grinding device that uniformly transmits indirect vacuum pressure across the entire surface of a wafer. Background Technology

[0002] A silicon wafer, which is widely used as a material for manufacturing semiconductor devices, refers to a thin sheet of single-crystal silicon made from polycrystalline silicon as a raw material.

[0003] These wafers are manufactured by growing polycrystalline silicon into a single-crystal silicon ingot, followed by a slicing process that cuts the rod-shaped silicon ingot into a thin wafer, a lapping process that flattens the thickness of the wafer, an etching process that removes or mitigates damage caused by mechanical grinding, a polishing process that mirrors the wafer surface, and a cleaning process that cleans the wafer.

[0004] Among the processes for manufacturing silicon wafers, a grinding process is additionally performed to grind the surface of the sliced ​​silicon wafer before the lapping or polishing process.

[0005] This grinding process is added to meet the high flatness required as semiconductor devices become more highly integrated, and it controls the thickness and flatness of the silicon wafer.

[0006] FIG. 1 is a side cross-sectional view showing a chuck table for a wafer grinding device of the prior art, and FIG. 2 is a drawing showing the operating state of the chuck table for a wafer grinding device of the prior art and the shape of the wafer after the process in sequence.

[0007] As shown in FIG. 1, a chuck table for a wafer grinding device of the prior art may include a porous section (10) made of a porous material on which a wafer (W) is placed, a body section (20) on which the porous section (10) is placed, and a plurality of vertical passages (30) vertically provided inside the body section (20) to communicate with the porous section (10) and provide vacuum pressure.

[0008] When looking at the operating state of a chuck table for a wafer grinding device of the prior art, as shown in FIG. 2, when vacuum pressure is provided to the vertical channels (30), the vacuum pressure is directly transmitted to the lower surface of the wafer (W) through the holes (10), and the wafer (W) is vacuum-adsorbed onto the chuck table.

[0009] Because the shape of the wafer (W) is curved according to the vacuum pressure distribution, the central part of the wafer (W) where vacuum pressure is not applied remains relatively bulging, whereas the peripheral part of the wafer (W) where vacuum pressure is applied remains relatively concave.

[0010] In this way, when a chuck table holding a wafer (W) in vacuum suction rotates in the forward direction and a grinding wheel equipped with a tip, which is a cutting tool in contact with the surface of the wafer (W), rotates in the opposite direction to perform the grinding process, the center of the wafer (W) is ground relatively more, while the periphery of the wafer (W) is ground relatively less, so a step difference occurs on the surface of the wafer (W).

[0011] According to conventional chuck tables, vacuum pressure is applied through multiple vertical channels located below the periphery of the wafer. Consequently, a pattern caused by the vacuum pressure is transferred to the lower surface of the wafer, and significant variations within the wafer surface occur, leading to a problem of surface step difference on the wafer after the grinding process. The problem to be solved

[0012] The embodiments aim to solve the aforementioned problems and other problems.

[0013] Another objective of the embodiment is to provide a chuck table for a wafer grinding device that uniformly transmits indirect vacuum pressure across the entire surface of the wafer. means of solving the problem

[0014] According to one aspect of an embodiment, a chuck table for a wafer grinding device is provided, comprising: a hollow portion on which a wafer is placed; a body portion on which the hollow portion is placed; and a vacuum channel provided inside the body portion and including a channel connected to the side of the hollow portion.

[0015] According to one aspect of the embodiment, the porous portion may be composed of a porous material capable of transmitting vacuum pressure in a disc type having a diameter smaller than the diameter of the wafer.

[0016] According to one aspect of the embodiment, the vacuum channel may be configured as a bypass channel connecting the side of the porous portion and the lower surface of the body portion.

[0017] According to one aspect of the embodiment, the vacuum channel may further include a vertical channel connecting the lower surface of the porous portion and the lower surface of the body portion.

[0018] According to one aspect of the embodiment, the vacuum channel can transmit vacuum pressure in a direction inclined from the center to the edge of the wafer. Effects of the invention

[0019] According to the embodiment, vacuum pressure is indirectly transmitted in a slanted direction from the center of the wafer to the edge through the side of the hollow portion supporting the wafer, thereby preventing the transfer of a pattern caused by vacuum pressure to the bottom surface of the wafer. In addition, by ensuring that vacuum pressure is transmitted uniformly across the entire bottom surface of the wafer to minimize variations within the wafer (W) surface, the grinding process can be performed while the overall shape of the wafer is flat, thereby improving the step difference on the wafer surface and providing the advantage of providing uniform grinding quality. Brief explanation of the drawing

[0020] FIG. 1 is a side cross-sectional view showing a chuck table for a wafer grinding device of the prior art. FIG. 2 is a drawing showing the operating state of a chuck table for a wafer grinding device of the prior art and the shape of the wafer after the process in sequence. FIG. 3 is a side cross-sectional view showing a chuck table for a wafer grinding device of the first embodiment. FIG. 4 is a drawing showing the operating state of the chuck table for the wafer grinding device of the first embodiment and the wafer shape after the process in sequence. FIG. 5 is a side cross-sectional view showing a chuck table for a wafer grinding device of the second embodiment. FIG. 6 is a drawing showing the operating state of the chuck table for the wafer grinding device of the second embodiment and the wafer shape after the process in sequence. Specific details for implementing the invention

[0021] Hereinafter, the present embodiment will be examined in detail with reference to the attached drawings.

[0022] FIG. 3 is a side cross-sectional view showing a chuck table for a wafer grinding device of the first embodiment, and FIG. 4 is a drawing showing the operating state of the chuck table for a wafer grinding device of the first embodiment and the wafer shape after the process in sequence.

[0023] As shown in FIGS. 3 and 4, the chuck table for a wafer grinding device of the first embodiment includes a hollow portion (110) on which a wafer (W) is placed, a body portion (120) on which the hollow portion (110) is placed, and a bypass channel (132), which is a vacuum channel provided inside the body portion (120) to connect the side of the hollow portion (110) and the lower surface of the body portion (120).

[0024] The porous section (110) is composed of a porous material containing pores capable of transmitting vacuum pressure and may be configured in a disc shape having a diameter smaller than the diameter of the wafer (W). The size and shape of the porous section (110) are not limited.

[0025] The body portion (120) may consist of an upper body that accommodates the side and bottom of the hollow portion (110) and a lower body provided on the lower side of the upper body, but it may also be composed of a single structure.

[0026] A bypass channel (132) may be formed inside the body portion (120) to be connected to the side of the porous portion (110) in order to transmit vacuum pressure to the porous portion (110). Since a plurality of bypass channels (132) are provided at regular intervals along the side of the porous portion (110), that is, along the circumference of the porous portion (110), vacuum pressure can be transmitted uniformly throughout the entire porous portion (110).

[0027] The above-mentioned bypass channel (132) can be configured in various ways to transmit vacuum pressure in a direction inclined from the center to the edge of the wafer (W), and is not limited to these configurations.

[0028] When a wafer (W) is placed on the chuck table for the wafer grinding device of the first embodiment configured as above and vacuum pressure is provided through the bypass channel (132), as shown in FIG. 4, the vacuum pressure is transmitted to the side of the porous section (110) through the bypass channel (132) and then transmitted to the entire lower surface of the wafer (W) through the porous section (110).

[0029] Therefore, due to the structure of the bypass channel (132), vacuum pressure is transmitted indirectly from the center of the wafer (W) to the edge in a slanted direction, so that a pattern caused by vacuum pressure is prevented from being transferred to the bottom surface of the wafer (W). In addition, by ensuring that vacuum pressure is transmitted uniformly across the entire bottom surface of the wafer (W) to minimize fluctuations within the wafer (W) surface, the grinding process can be carried out while the overall shape of the wafer (W) is flat, thereby improving the step difference on the wafer surface and providing uniform grinding quality.

[0031] FIG. 5 is a side cross-sectional view showing a chuck table for a wafer grinding device of the second embodiment, and FIG. 6 is a drawing showing the operating state of the chuck table for a wafer grinding device of the second embodiment and the wafer shape in sequence.

[0032] The chuck table for the wafer grinding device of the second embodiment is configured in the same way as the first embodiment as shown in FIGS. 5 and 6, and may include a bypass channel (132) and a vertical channel (134) to provide vacuum pressure.

[0033] While the bypass channel (132) is formed inside the body part (120) to be connected to the side of the porous section (110), the vertical channel (134) can be formed in the body part (120) to be connected to the bottom surface of the porous section (110). Since a plurality of bypass channels (132) are provided at regular intervals along the side of the porous section (110), that is, along the circumference of the porous section (110), and a plurality of vertical channels (134) are provided at regular intervals on the bottom surface of the porous section (110), a more uniform and strong vacuum pressure can be transmitted throughout the entire porous section (110).

[0034] The above-mentioned bypass channel (132) and vertical channel (134) can be configured in various ways to transmit vacuum pressure in a direction inclined from the center to the edge of the wafer (W), and are not limited to these configurations.

[0035] In the second embodiment configured as described above, the chuck table for the wafer grinding device also transmits vacuum pressure indirectly from the center of the wafer (W) to the edge in a slanted direction, just like in the first embodiment, and transmits it uniformly across the entire bottom surface of the wafer (W), thereby preventing the transfer of a pattern caused by vacuum pressure to the bottom surface of the wafer (W) and providing uniform grinding quality.

[0037] The above description is merely an illustrative explanation of the technical concept of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications and variations within the scope of the essential characteristics of the present invention.

[0038] Accordingly, the embodiments disclosed in this invention are intended to explain, not limit, the technical concept of the invention, and the scope of the technical concept of the invention is not limited by these embodiments.

[0039] The scope of protection of the present invention shall be interpreted by the claims below, and all technical ideas within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention. Explanation of the symbols

[0040] 110 : Multi-purpose 120 : Body 132 : Bypass Euro 134 : Vertical Euro W : Wafer

Claims

Claim 1 A chuck table for a wafer grinding device comprising: a porous portion on which a wafer is placed; a body portion on which the porous portion is placed; and a vacuum channel provided inside the body portion and connected to the side of the porous portion. Claim 2 In claim 1, the above-mentioned porous portion is a chuck table for a wafer grinding device composed of a porous material capable of transmitting vacuum pressure in a disc type having a diameter smaller than the diameter of the wafer. Claim 3 A chuck table for a wafer grinding device according to claim 1, wherein the vacuum channel is composed of a bypass channel connecting the side of the porous portion and the lower surface of the body portion. Claim 4 A chuck table for a wafer grinding device according to claim 1, wherein the vacuum channel further comprises a vertical channel connecting the lower surface of the porous portion and the lower surface of the body portion. Claim 5 In any one of claims 1 to 4, the vacuum channel is a chuck table for a wafer grinding device that transmits vacuum pressure in a direction inclined from the center to the edge of the wafer.

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