Polishing apparatus for substrate and polishing method for substrate using the same

Abstract

One embodiment of the present invention provides a substrate polishing device comprising: a platen having a polishing pad attached to its upper surface and installed to be rotatable in one direction; a temperature control unit having a lower surface in contact with the polishing pad and controlling the surface temperature of the polishing pad; a polishing head installed on the polishing pad, spaced apart from the temperature control unit in the one direction, and rotating a semiconductor substrate by pressing it against the polishing pad; a slurry supply unit installed on the polishing pad, spaced apart from the polishing head in the one direction, and supplying a slurry to the polishing pad; and a cleaning unit disposed on the outer edge of the platen and cleaning the lower surface by contacting at least a portion of the lower surface of the temperature control unit, wherein the temperature control unit contacts at least a portion of the upper surface of the cleaning unit of the polishing pad while the platen is rotating.

Description

Technology Field

[0001] The present invention relates to a substrate polishing apparatus and a substrate polishing method using the same. Background Technology

[0003] The manufacturing of semiconductor devices can be performed through various processes. For example, the manufacturing of semiconductor devices may proceed through photolithography, etching, and deposition processes on a wafer. Prior to each process, it may be necessary to flatten the surface of the wafer. To this end, a polishing process may be performed on the wafer. The polishing process can be carried out in various ways. For example, a chemical mechanical polishing (CMP) process may be used to flatten the wafer.

[0004] Recently, in order to improve the efficiency of the CMP process, a temperature control unit is brought into contact with a polishing pad placed on a platen where the CMP process is performed to control the surface temperature of the polishing pad. However, the surface of the temperature control unit is contaminated by the slurry and polishing pad byproducts used in the CMP process, and a problem arises in which the temperature control efficiency of the temperature control unit is reduced. The problem to be solved

[0006] One of the technical problems that the technical concept of the present invention aims to solve is to provide a substrate polishing device and a substrate polishing method capable of cleaning a temperature control unit while the CMP process is being performed. means of solving the problem

[0008] One embodiment of the present invention provides a substrate polishing device comprising: a platen having a polishing pad attached to its upper surface and installed to be rotatable in one direction; a temperature control unit having a lower surface in contact with the polishing pad and controlling the surface temperature of the polishing pad; a polishing head installed on the polishing pad, spaced apart from the temperature control unit in the one direction, and rotating a semiconductor substrate by pressing it against the polishing pad; a slurry supply unit installed on the polishing pad, spaced apart from the polishing head in the one direction, and supplying a slurry to the polishing pad; and a cleaning unit disposed on the outer edge of the platen and cleaning the lower surface by contacting at least a portion of the lower surface of the temperature control unit, wherein the temperature control unit contacts at least a portion of the upper surface of the cleaning unit of the polishing pad while the platen is rotating.

[0009] One embodiment of the present invention provides a substrate polishing method comprising: a step of placing a semiconductor substrate on the upper surface of a platen using a polishing head; a step of contacting the semiconductor substrate on a polishing pad that rotates in one direction; and a step of supplying a slurry onto the polishing pad, polishing the semiconductor substrate by rotating the polishing head, and contacting a temperature control unit to the polishing pad, wherein a first region of the lower surface of the temperature control unit contacts the polishing pad to control the surface temperature of the polishing pad, wherein the step of controlling the surface temperature of the polishing pad includes a step of cleaning the lower surface of the temperature control unit by contacting at least a portion of a second region other than the first region of the lower surface of the temperature control unit with a cleaning unit disposed on the outer edge of the platen. Effects of the invention

[0011] A substrate polishing apparatus and a substrate polishing method according to one embodiment of the present invention may clean the temperature control unit by arranging a cleaning unit capable of cleaning the temperature control unit on the outer edge of a platen, so that the temperature control unit can be cleaned during the performance of a CMP process.

[0012] The various and beneficial advantages and effects of the present invention are not limited to those described above and will be more easily understood in the process of explaining specific embodiments of the present invention. Brief explanation of the drawing

[0014] FIG. 1 is a schematic perspective view of a substrate polishing device according to one embodiment. Figure 2 is a plan view of Figure 1 from direction 'A'. FIGS. 3 to 5 are various variations of the substrate polishing device of FIG. 1. Specific details for implementing the invention

[0015] Hereinafter, embodiments of the present invention will be described as follows with reference to the attached drawings.

[0017] Referring to FIGS. 1 to 3, a substrate polishing apparatus according to one embodiment will be described. FIG. 1 is a schematic perspective view of a substrate polishing apparatus according to one embodiment, and FIG. 2 is a plan view seen from direction 'A' of FIG. 1.

[0019] Referring to FIGS. 1 and 2, the substrate polishing device (1) may have a temperature control unit (20), a polishing head (30), a slurry supply unit (40), and a conditioner (50) sequentially arranged along one direction (D1), which is the rotational direction of the platen (10), on a platen (10), and a cleaning unit (60) may be spaced apart and arranged on the outer edge of the platen (10). The substrate polishing device (1) of one embodiment may be used in a process of chemical mechanical polishing a semiconductor substrate (W), such as a wafer.

[0021] The platen (10) may be formed in a disc shape, and a polishing pad (11) providing a place for chemical mechanical polishing of the semiconductor substrate (W) may be attached to its upper surface. The upper surface of the polishing pad (11) may serve as a polishing surface for polishing the semiconductor substrate (W). Additionally, the platen (10) may have a rotation axis (12) connected to its lower portion and may rotate in one direction (D1) by a driving device such as a motor. The platen (10) may rotate clockwise or counterclockwise around the rotation axis (12). One embodiment is described by citing the case where the platen (10) rotates clockwise.

[0023] The temperature control unit (20) can be used to raise or lower the surface temperature of the polishing pad (11) by maintaining a temperature higher or lower than the surface temperature of the polishing pad (11). The temperature control unit (20) can be positioned above the polishing pad (11) and spaced apart from the slurry supply unit (40). Additionally, the temperature control unit (20) can be positioned at the front end of the polishing head (30) with respect to one direction (D1) and at the rear end of the conditioner (50). The temperature control unit (20) can be made of ceramic material and can be formed in a disc shape, but is not limited thereto and can be modified into various shapes. The lower surface of the temperature control unit (20) can be formed as a flat surface and can directly contact the upper surface of the polishing pad (11) to control the surface temperature of the polishing pad (11).

[0024] According to an embodiment, the temperature control unit (20) may be driven by a driving device such as a motor, with a driving shaft (21) connected to the upper part. The driving shaft (21) may rotate the temperature control unit (20), move it in a direction parallel to the upper surface of the polishing pad (11), or move up and down relative to the upper surface of the polishing pad (11). When the driving shaft (21) rotates, the temperature control unit (20) may rotate at a constant rotational speed due to the rotation of the driving shaft (21). At this time, the direction of rotation of the driving shaft (21) may be the same direction as the direction (D1) in which the platen (10) rotates. Additionally, when the driving shaft (21) moves in a direction parallel to the upper surface of the polishing pad, the temperature control unit (20) may move in a straight line or reciprocate on the polishing pad (11), and according to an embodiment, the temperature control unit (20) may reciprocate between the polishing pad (11) and the cleaning unit (60). Additionally, when the drive shaft (21) moves up and down relative to the upper surface of the polishing pad (11), the temperature control unit (20) may be separated from or come into contact with the upper surface of the polishing pad (11) as the drive shaft (21) moves up and down.

[0025] The temperature control unit (20) may be positioned to overlap the upper surface of the polishing pad (11) and the upper surface of the cleaning unit (60), respectively. That is, the lower surface (20U) of the temperature control unit (20) may have a first area (AR1) and a second area (AR2) which is an area other than the first area (AR1), and the first area (AR1) may be in contact with the upper surface of the polishing pad (11), and at least a portion of the second area (AR2) may be in contact with the upper surface of the cleaning unit (60). Additionally, according to an embodiment, the temperature control unit (20) may come into contact with the upper surface of the polishing pad (11) and the upper surface of the cleaning unit (60) simultaneously or alternately as the drive shaft (21) moves in a straight direction (D2).

[0026] In the temperature control unit (20), an inlet pipe (22) and an outlet pipe (23) through which fluid flows are arranged so that the temperature of the temperature control unit (20) can be controlled as the temperature of the fluid is controlled.

[0027] As such, the temperature control unit (20) controls the surface temperature of the polishing pad (11) by directly contacting the polishing pad (11), so compared to the case where the surface temperature of the polishing pad (11) is controlled by spraying a temperature control fluid onto the polishing pad (11), the speed of temperature control is faster and there is an advantage that the mixing of the temperature control fluid and the slurry applied to the polishing pad (11) can be prevented. However, as the temperature control unit (20) is in direct contact with the polishing pad (11), the lower surface (20U) of the temperature control unit (20) can easily become contaminated by contaminants such as the slurry or polishing by-products applied to the polishing pad (11). If the contaminants attached to the lower surface (20U) of the temperature control unit (20) solidify, it may cause a problem that lowers the temperature control efficiency of the temperature control unit (20). In one embodiment, the substrate polishing device (1) can resolve the problem of low temperature control efficiency of the temperature control unit (20) by cleaning contaminants of the temperature control unit (20) using the cleaning unit (60). This will be described later.

[0029] The polishing head (30) may be positioned above the polishing pad (11) at a distance from the temperature control unit (20). Additionally, it may be positioned at the front end of the slurry supply unit (40) with respect to one direction (D1). A semiconductor substrate (W) to be chemically mechanically polished may be attached to the lower part of the polishing head (30) by vacuum. The polishing head (30) can chemically mechanically polish the surface of the semiconductor substrate (W) by applying a constant polishing load to the semiconductor substrate (W) to bring the semiconductor substrate (W) into contact with the polishing pad (11) and rotating it by the rotation axis (32). Additionally, according to the embodiment, the polishing head (30) may perform reciprocating motion along with rotational motion on the polishing pad (11).

[0031] The slurry supply unit (40) may be positioned above the polishing pad (11) at a distance from the polishing head (30). The slurry supply unit (40) may be positioned at the front end of the polishing head (30) with respect to one direction (D1). The slurry supply unit (40) is provided with at least one nozzle (41) and can spray slurry (SL) onto the surface of the polishing pad (11) through the nozzle (41). The slurry (SL) sprayed from the slurry supply unit (40) can be discharged to the outer edge of the platen (10) after being used to polish the surface of the semiconductor substrate (W) at the polishing head (30). According to an embodiment, the slurry supply unit (40) may spray the slurry (SL) while it is heated or cooled. The slurry (SL) supplied from the slurry supply unit (40) can be used to perform a chemical mechanical polishing process by reacting with the surface of a semiconductor substrate (W) attached to a polishing head (30).

[0033] The cleaning unit (60) may be positioned on the outer edge of the platen (10). The cleaning unit (60) may include a disc-shaped cleaning unit body (61), a cleaning pad (62) coupled to the upper surface of the cleaning unit body (61), and a cleaning unit body rotation axis (63) coupled to the lower surface (20U) of the cleaning unit body (61). According to an embodiment, the cleaning unit (60) may further include a cleaning liquid supply unit (64) that sprays cleaning liquid (CL) onto the cleaning pad (62). According to an embodiment, the cleaning unit body rotation axis (63) may be replaced with a support axis that does not rotate. The cleaning unit (60) may be used to clean the temperature control unit (20).

[0034] According to an embodiment, the cleaning body (61) may rotate at a constant rotational speed by the rotation of the cleaning body rotation axis (63). For example, the cleaning body (61) may rotate in the same direction (D1) as the platen (10) rotates. However, it is not limited thereto, and according to an embodiment, the cleaning body (61) may not rotate.

[0035] The cleaning pad (62) may be placed on the lower surface of the cleaning body (61). The cleaning pad (62) may be disc-shaped like the cleaning body, but is not limited thereto and may be modified into various shapes.

[0036] The cleaning pad (62) may be formed from a non-woven fabric material. For example, the cleaning pad (62) may be formed by compressing polyethylene fibers or the like into a polymer. The cleaning pad (62) may come into contact with the temperature control unit (20) to wipe away contaminants (ABP) attached to the temperature control unit (20). If the cleaning unit (60) includes a cleaning liquid supply unit (64), the cleaning liquid supply unit (64) may spray a cleaning liquid (CL) onto the cleaning pad (62) to improve the cleaning effect of the cleaning pad (62). The cleaning liquid supply unit (64) may have at least one nozzle and may spray the cleaning liquid (CL) onto the cleaning pad (62). For example, ultrapure water (De-Ionized Water) may be used as the cleaning liquid (CL). Additionally, the cleaning solution (CL) may be heated or cooled to the same temperature as the temperature control unit (20) in order to maintain the surface temperature of the cleaning pad (62) in contact with the polishing pad (11) at the same temperature as the surface temperature of the polishing pad (11).

[0038] As previously explained, the temperature control unit (20) employed in the substrate polishing device (1) of one embodiment is in direct contact with the polishing pad (11), so as shown in FIG. 2, the lower surface (20U) can be easily contaminated by contaminants (ABP), such as slurry or polishing byproducts applied to the polishing pad (11). A cleaning unit (60) positioned on the outer edge of the polishing pad (11) can clean the contaminants (ABP) by contacting the second region (AR2) of the lower surface (20U) of the temperature control unit (20). Therefore, the problem of low temperature control efficiency of the temperature control unit (20) can be resolved in the substrate polishing device (1) of one embodiment.

[0040] Referring again to FIG. 1, the conditioner (50) may be placed between the slurry supply unit (40) and the temperature control unit (20). The conditioner (50) may perform a conditioning process to reproduce the roughness of the polishing pad (11) by polishing the surface of the polishing pad (11) with a disc to which diamond particles are attached, in order to make the surface condition of the polishing pad (11) uniform.

[0042] The cleaning unit (60) can be modified in various ways. FIGS. 3 to 5 are examples of various modifications to the cleaning unit.

[0043] Referring to FIG. 3, the substrate polishing device (1A) of one embodiment differs from the previously described embodiment in that the center of the cleaning pad (62A) of the cleaning unit (60A) has a protruding shape. Since the other configurations are identical to those of the previously described embodiment, they are omitted to prevent duplication of description.

[0044] In one embodiment, the cleaning pad (62A) may include a lower cleaning pad (62A_1) and an upper cleaning pad (62A_2). The lower cleaning pad (62) may be disc-shaped, and an upper cleaning pad (62) having a smaller diameter than the lower cleaning pad (62) may be placed in the center of the lower cleaning pad (62). That is, the cleaning pad (62A) in one embodiment may have a shape with a protruding center. The lower cleaning pad (62) may be placed to form a co-plane with the lower surface (20U) of the temperature control unit (20), and the upper cleaning pad (62) may be placed to correspond to the side surface (20E) of the temperature control unit (20). Accordingly, the lower cleaning pad (62) can clean the lower surface (20U) of the temperature control unit (20), and the upper cleaning pad (62) can clean the side surface (20E) of the temperature control unit (20). Therefore, the cleaning unit (60A) of one embodiment has the advantage of being able to clean both the lower surface (20U) and the side surface (20E) of the temperature control unit (20).

[0046] Referring to FIG. 4, the substrate polishing device (1B) of one embodiment differs from the previously described embodiment in that the cleaning unit (60B) has a brush attached to it. The other configurations are identical to those of the previously described embodiment, so they are omitted to avoid duplication of description.

[0047] In one embodiment, the cleaning unit (60B) may include a cleaning unit body (61) and a brush (62B). The cleaning unit body (61) may move back and forth along the direction (D3) in which the platen (10) is positioned to adjust the distance between the cleaning unit (60B) and the platen (10).

[0048] The brush (62B) is positioned on the side of the cleaning unit body (61B) toward the platen (10), so that as the cleaning unit (60B) moves, it may be separated from or come into contact with the temperature control unit (20). The upper surface of the brush (62B) may be positioned to have a higher level than the lower surface (20U) of the temperature control unit (20), and the lower surface of the brush (62B) may be positioned to have a lower level than the lower surface (20U) of the temperature control unit (20). Thus, the brush (62B) may come into contact with both the lower surface (20U) and the side surface (20E) of the temperature control unit (20) simultaneously. Therefore, the cleaning unit (60B) of one embodiment has the advantage of being able to clean both the lower surface (20U) and the side surface (20E) of the temperature control unit (20).

[0050] Referring to FIG. 5, the substrate polishing device (1C) of one embodiment differs from the previously described embodiment in that the cleaning unit (60C) is cylindrical in shape. Since the other configurations are identical to those of the previously described embodiment, they are omitted to avoid duplication of description.

[0051] A cleaning pad (62) of one embodiment may include a cylindrical cleaning body (61C) having a rotation axis (63) arranged parallel to the side (20E) of the temperature control unit (20), and a brush (62C) arranged on the side of the cleaning body (61C). The brush (62C) may be formed of polyvinyl alcohol. The brush (62C) rotates in a direction (D4) perpendicular to the side (20E) of the temperature control unit (20) by the rotation axis (63), and can simultaneously clean the lower surface (20U) and the side (20E) of the temperature control unit (20). Therefore, the cleaning unit (60C) of one embodiment has the advantage of being able to clean both the lower surface (20U) and the side (20E) of the temperature control unit (20).

[0053] Next, a substrate polishing method according to one embodiment will be described. The substrate polishing method according to one embodiment can be performed using the substrate polishing device (1) of FIG. 1. Since the substrate polishing device (1) of FIG. 1 has been described previously, a detailed description is omitted.

[0054] First, a semiconductor substrate (W) can be attached to the polishing head (30) of the substrate polishing device (1) and placed on the platen (10).

[0055] Next, a semiconductor substrate (W) can be brought into contact with a polishing pad (11) that rotates in one direction (D1).

[0056] Next, a slurry (SL) is supplied onto the polishing pad (11), and the polishing head (30) is rotated to polish the semiconductor substrate (W), and the surface temperature of the polishing pad (11) can be controlled by contacting the temperature control unit (20) with the polishing pad (11). At this time, the first region (AR1) of the lower surface (20U) of the temperature control unit (20) is contacted with the polishing pad (11), and at least a portion of the second region (AR2) of the lower surface (20U) of the temperature control unit (20) is contacted with the cleaning unit (60) located on the outer edge of the platen (10) so that the lower surface (20U) of the temperature control unit (20) can be cleaned.

[0058] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, and such are also to be considered to fall within the scope of the present invention. Explanation of the symbols

[0060] 1: Substrate polishing device 10: Platen 11: Grinding pad 12: Rotating shaft 20: Temperature control unit 21: Drive shaft 22: Inlet pipe 23: Outlet pipe 30: Grinding head 40: Slurry supply unit 50: Conditioner 60: Cleaning unit 61; Cleaning unit body 62: Cleaning pad 63: Cleaning solution body rotation axis 64: Cleaning solution supply unit CL: Cleaning solution SL: Slurry W: Semiconductor substrate

Claims

Claim 1 A substrate polishing device comprising: a platen having a polishing pad attached to its upper surface and installed to be rotatable in one direction; a temperature control unit having a lower surface in contact with the polishing pad and controlling the surface temperature of the polishing pad; a polishing head installed on the polishing pad, spaced apart from the temperature control unit in one direction, and rotating a semiconductor substrate by pressing it against the polishing pad; a slurry supply unit installed on the polishing pad, spaced apart from the polishing head in one direction, and supplying a slurry to the polishing pad; and a cleaning unit disposed on the outer edge of the platen and cleaning the lower surface by contacting at least a portion of the lower surface of the temperature control unit, wherein the temperature control unit includes a first region that contacts the polishing pad while the platen is rotating and a second region that protrudes outward from the platen and contacts at least a portion of the upper surface of the cleaning unit. Claim 2 A substrate polishing device according to claim 1, wherein the cleaning unit comprises: a cleaning unit body; a cleaning pad connected to the upper surface of the cleaning unit body; and a cleaning unit body rotation axis connected to the lower surface of the cleaning unit body, wherein the upper surface of the cleaning pad is disposed coplanar with the upper surface of the polishing pad. Claim 3 A substrate polishing device according to paragraph 2, wherein the cleaning pad comprises: a disc-shaped lower cleaning pad; and an upper cleaning pad having a diameter smaller than the diameter of the lower cleaning pad and positioned in the center of the lower cleaning pad, wherein the upper surface of the lower cleaning pad contacts the lower surface of the temperature control unit and the side surface of the upper cleaning pad contacts the side surface of the temperature control unit. Claim 4 delete Claim 5 In paragraph 2, the cleaning unit comprises: a cylindrical cleaning unit body having a rotation axis parallel to the side of the temperature control unit; and a brush disposed on the side of the cleaning unit body, forming a substrate polishing device. Claim 6 In paragraph 2, the cleaning pad is a substrate polishing device made of a material different from the polishing pad. Claim 7 In paragraph 6, the cleaning pad is a substrate polishing device made of non-woven fabric. Claim 8 In claim 1, the temperature control unit is a substrate polishing device that rotates in one direction in contact with the polishing pad. Claim 9 delete Claim 10 A substrate polishing method comprising: a step of placing a semiconductor substrate on the upper surface of a platen using a polishing head; a step of contacting the semiconductor substrate onto a polishing pad rotating in one direction; and a step of supplying a slurry onto the polishing pad, polishing the semiconductor substrate by rotating the polishing head, and contacting a temperature control unit to the polishing pad, wherein a first region of the lower surface of the temperature control unit contacts the polishing pad to control the surface temperature of the polishing pad, wherein the step of controlling the surface temperature of the polishing pad includes a step of cleaning the lower surface of the temperature control unit by contacting at least a portion of a second region protruding outward from the outer surface of the platen other than the first region that contacts the polishing pad with the second region of the lower surface of the temperature control unit with a cleaning unit disposed on the outer surface of the platen.

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