Patent Application
20250153305
This application is based on and claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2023-0157687, filed on Nov. 14, 2023, in the Korean Intellectual Property Office, the disclosure of which is incorporated by reference herein in its entirety.
The present disclosure relates to a chemical mechanical polishing pad and a chemical mechanical polishing apparatus including the chemical mechanical polishing pad, and more particularly, to a chemical mechanical polishing pad having grooves formed therein and a chemical mechanical polishing apparatus including the chemical mechanical polishing pad.
Chemical mechanical polishing processes using chemical mechanical polishing apparatuses are used to planarize substrates when manufacturing semiconductor devices. Also, the chemical mechanical polishing process is performed to polish the surface of the substrate using chemical mechanical interaction between the substrate and a chemical mechanical polishing pad. In addition, the chemical mechanical polishing pad has grooves with various patterns for smooth supply of slurry abrasives.
Embodiments of the present disclosure provide a chemical mechanical polishing pad having a constant polishing rate and applying uniform pressure to a substrate, and a chemical mechanical polishing apparatus including the chemical mechanical polishing pad.
According to an aspect of the present disclosure, chemical mechanical polishing pad is provided and includes a body having a cylindrical shape and extending in a vertical direction, the body including: a plurality of first grooves extending downward in the vertical direction from an upper surface of the body; and a plurality of second grooves extending downward in the vertical direction inside the body, wherein each of the plurality of first grooves is exposed upward in the vertical direction from the upper surface of the body, wherein each of the plurality of second grooves is inside the body such that an upper surface of each of the plurality of second grooves is below the upper surface of the body, and wherein at least two of the plurality of first grooves have different depths from each other.
According to an aspect of the present disclosure, a chemical mechanical polishing apparatus is provided and includes: a plate configured to rotate about a vertical axis; a chemical mechanical polishing pad on an upper surface of the plate; a polishing head facing the chemical mechanical polishing pad in a vertical direction; and a slurry supply above the plate, spaced apart from the polishing head in a horizontal direction, and configured to discharge polishing slurry toward an upper surface of the chemical mechanical polishing pad. The chemical mechanical polishing pad includes a body including: a plurality of first grooves extending downward in the vertical direction from the upper surface of the chemical mechanical polishing pad; and a plurality of second grooves extending downward in the vertical direction inside the body such that an upper surface of each of the plurality of second grooves is below an upper surface of the body, wherein at least two of the plurality of first grooves have different depths in the vertical direction from each other, and wherein the upper surfaces of at least two of the plurality of second grooves are at different vertical levels from each other.
According to an aspect of the present disclosure, a chemical mechanical polishing apparatus is provided and includes: a plate configured to rotate about a vertical axis; a chemical mechanical polishing pad on an upper surface of the plate; a polishing head facing the chemical mechanical polishing pad in a vertical direction; a slurry supply above the plate, spaced apart from the polishing head in a horizontal direction, and configured to discharge polishing slurry toward an upper surface of the chemical mechanical polishing pad; and a pad cleaner above the chemical mechanical polishing pad and configured to clean the chemical mechanical polishing pad. The chemical mechanical polishing pad includes a body including: a plurality of first grooves extending downward in the vertical direction from the upper surface of the chemical mechanical polishing pad; and a plurality of second grooves extending downward in the vertical direction inside the body such that upper surfaces of each of the plurality of second grooves are below an upper surface of the body, wherein at least two of the plurality of first grooves have different depths in the vertical direction from each other, and wherein the upper surfaces of at least two of the plurality of second grooves are at different vertical levels from each other, wherein at least one of the plurality of first grooves and at least one of the plurality of second grooves overlap each other in the horizontal direction, and wherein each of the plurality of first grooves and the plurality of second grooves has a spiral cross-section on an horizontal plane.
Aspects of embodiments of the present disclosure are not limited to the aforementioned aspects, and other aspects not described above will be clearly understood by those skilled in the art from the following description.
Embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which:
Hereinafter, non-limiting example embodiments of the present disclosure are described in detail with reference to the accompanying drawings. The same reference numerals are given to the same elements in the drawings, and repeated descriptions thereof may be omitted.
It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers present.
Referring to
The plate 20 may support the chemical mechanical polishing pad 100 and may be configured to be rotatable. According to embodiments, the plate 20 may have a cylindrical shape, and the upper surface of the plate 20 may be flat. The plate 20 may have a footprint greater than a footprint of the chemical mechanical polishing pad 100. The plate 20 may receive rotational power from a motor located in a lower base, and accordingly, the plate 20 may be rotated in a certain direction, such as clockwise or counterclockwise, by a rotary shaft perpendicular to the surface of the plate 20.
In the drawings, an X-axis direction and a Y-axis direction may represent directions parallel to the upper or lower surface of the plate 20, and the X-axis direction and the Y-axis direction may be perpendicular to each other. The Z-axis direction may be perpendicular to the upper or lower surface of the plate 20 and represent a rotation axis of the plate 20. In other words, the Z-axis direction may be perpendicular to the X-Y plane.
Also, in the drawings, a first horizontal direction, a second horizontal direction, and a vertical direction may be understood as follows. The first horizontal direction may be understood as the X-axis direction, the second horizontal direction may be understood as the Y-axis direction, and the vertical direction may be understood as the Z-axis direction.
The chemical mechanical polishing pad 100 may be disposed on the upper surface of the plate 20. The chemical mechanical polishing pad 100 may rotate clockwise or counterclockwise about the Z-axis by the rotation of the plate 20. The chemical mechanical polishing pad 100 may be in direct contact with an object to be polished (hereinafter, referred to as a workpiece) when a polishing process is performed. The chemical mechanical polishing pad 100 may chemically and/or mechanically polish the surface of the workpiece using nano-abrasive particles in the polishing slurry. Here, the workpiece may include, for example, a substrate W, and the polishing surface of the chemical mechanical polishing pad 100 may include, for example, a surface in direct contact with the workpiece and a portion corresponding to a certain depth from the contact surface. The configuration of the chemical mechanical polishing pad 100 is described below in detail with reference to
The polishing head 10 may be located above the plate 20. The polishing head 10 may be spaced apart from the upper surface of the plate 20 by a certain distance in a vertical direction Z. The polishing head 10 may hold the workpiece. The polishing head 10 may be configured to rotate the workpiece. The polishing head 10 may rotate clockwise or counterclockwise about the Z axis. According to embodiments, the rotation direction of the polishing head 10 may be the same as or opposite to the rotation direction of the plate 20.
The slurry supply unit 40 may be configured to discharge polishing slurry onto the upper surface of the chemical mechanical polishing pad 100. The slurry supply unit 40 may receive the polishing slurry from a polishing slurry tank. The slurry supply unit 40 may include a nozzle that discharges the polishing slurry toward the chemical mechanical polishing pad 100 and a voltage supply unit that applies a certain voltage to the nozzle. The polishing slurry stored in the nozzle may be charged by the voltage applied from the voltage supply unit, and accordingly, the polishing slurry may be discharged onto the upper surface of the chemical mechanical polishing pad 100. According to embodiments, the polishing slurry may include nano-abrasive particles having an average particle diameter of less than about 10 nm. The slurry supply unit 40 may be located above the chemical mechanical polishing pad 100. The slurry supply unit 40 may be spaced apart from the upper surface of the chemical mechanical polishing pad 100 by a certain distance in the vertical direction Z. According to embodiments, the slurry supply unit 40 may be located above the center of the chemical mechanical polishing pad 100.
The pad cleaning unit 30 may be located above the chemical mechanical polishing pad 100 and spaced apart from the upper surface of the chemical mechanical polishing pad 100 by a certain distance in the vertical direction Z. According to embodiments, the pad cleaning unit 30 may be located above an edge region of the chemical mechanical polishing pad 100. The pad cleaning unit 30 may keep the surface roughness of the polishing surface of the chemical mechanical polishing pad 100 constant so that the workpiece may be effectively polished during the polishing process. For example, the pad cleaning unit 30 may clean the polishing surface of the chemical mechanical polishing pad 100 while the workpiece is being polished or when the polishing process is stopped. Accordingly, the surface roughness of the polishing surface of the chemical mechanical polishing pad 100 may be recovered or maintained. The pad cleaning unit 30 may rotate clockwise or counterclockwise about the Z axis.
Referring to
According to embodiments, the body 110 may include a polymer, for example, polyurethane. The polyurethane may be obtained by, for example, mixing a hardening agent with a polyurethane precursor that is obtained through a reaction of an isocyanate compound and a polyol compound.
The isocyanate compound may include, for example, aliphatic isocyanate and/or aromatic isocyanate and may include, for example, diisocyanate. For example, the isocyanate compounds may include, but not limited to, ethylene diisocyanate, hexamethylene diisocyanate, bis(isocyanatomethyl)cyclohexane, norbornane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, naphthalene diisocyanate, phenylene diisocyanate, tolidine diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, xylene diisocyanate, or a combination thereof.
For example, the polyol compound may include, but not limited to, polyether polyol, polyester polyol, polycarbonate polyol, polyester polycarbonate polyol, acrylic polyol, or a combination thereof.
Also, the body 110 may include acrylonitrile butadiene styrene copolymer (ABS) resin. The ABS resin may include, but not limited to, acrylonitrile, butadiene, and styrene, or a combination thereof.
The first groove 120 may extend downward in the vertical direction Z from the upper surface of the body 110. The inside of the body 110 may be exposed by the first groove 120. A plurality of first grooves 120 may be provided. The plurality of first grooves 120 may be spaced apart from each other by a certain distance. At least two of the plurality of first grooves 120 may have different depths from each other.
The second groove 130 may extend downward in the vertical direction Z inside the body 110. The second groove 130 is located inside the body 110, and thus, the second groove 130 may be understood as an empty space formed inside the body 110. The second groove 130 may be surrounded by the body 110. A plurality of second grooves 130 may be provided. The plurality of second grooves 130 may be spaced apart from each other by a certain distance. At least two of the plurality of second grooves 130 may have different depths from each other.
The first groove 120 is exposed upward in the vertical direction Z from the upper surface of the body 110, and thus, the polishing slurry provided during the polishing process may fill the first groove 120. On the other hand, the second groove 130 is not exposed to the outside by the body 110, and thus, the polishing slurry may not be provided into the second groove 130. However, when the upper surface of the body 110 wears down as the polishing process progresses, the second groove 130 may be exposed upward in the vertical direction Z from the upper surface of the body 110. At this moment, the polishing slurry may fill the second groove 130. That is, at the beginning of the polishing process when the body 110 does not wear down, the polishing slurry may fill the first grooves 120. However, when the body 110 has worn down to a certain depth or more, the polishing slurry may fill the second grooves 130.
Each of the first grooves 120 extends downward in the vertical direction Z from the upper surface of the body 110, and thus, the upper ends of the first grooves 120 may all be on the same plane. Here, each of the upper ends of the first grooves 120 may be a virtual surface and may be defined as a virtual surface at the same vertical level as the upper surface of the body 110. The first grooves 120 may disappear due to wear of the body 110. For example, when wear of the body 110 progresses to the depth of a certain first groove 120, the first groove 120 may no longer exist. However, the plurality of first grooves 120 have different depths from each other. Therefore, even if one of the first grooves 120 disappears due to wear of the body 110, another first groove 120, which has a greater depth than the disappeared first groove 120, may still exist despite the wear of the body 110. That is, even though the body 110 is wearing down, some of the plurality of first grooves 120 may disappear at a certain point in time, but other first grooves 120 may still exist. However, the first grooves 120 that still exist may have a smaller volume than before the body 110 has worn down.
Each of the second grooves 130 may extend downward in the vertical direction Z inside the body 110, and the upper ends (e.g., upper surfaces) of at least two of the plurality of second grooves 130 may be at different vertical levels from each other. Here, each of the upper ends of the second grooves 130 is a virtual surface and may be defined as a vertical surface at the highest vertical level of each of the second grooves 130. The upper ends of at least two of the plurality of second grooves 130 are at different vertical levels from each other. Therefore, when the second groove 130 is exposed upward from the body 110 in the vertical direction Z as the body 110 is wearing down, another second groove 130 may still be inside the body 110 such as to not be exposed. For example, when the upper end of one second groove 130 is at a higher vertical level than the upper end of another second groove 130, the second groove 130, of which the upper end is at a higher vertical level among the two second grooves 130, may be exposed earlier in the vertical direction Z due to wear of the body 110 and the second groove 130, of which the upper end is at a lower vertical level between the two second grooves 130, may be exposed upward in the vertical direction Z after the body 110 further wears down. Accordingly, the second groove 130, of which the upper end is at a higher vertical level, may be first filled with the polishing slurry. According to embodiments, the lower surfaces of the second grooves 130 may all be at the same vertical level.
According to embodiments, the cross-sections, on the Y-Z plane, of at least two first grooves 120 among the plurality of first grooves 120 may have the same shape and area. Here, the cross-sections on the Y-Z plane of the first grooves 120 include virtual planes, and each of the virtual planes may have the same shape and area as the cross-section on the Y-Z plane of a material when the first groove 120 is filled with the material. However, since the depths of at least any two of the plurality of first grooves 120 may be different from each other, the shapes and areas of the two first grooves 120 may be different from each other.
According to embodiments, the cross-sections, on the Y-Z plane, of at least two second grooves 130 among the plurality of second grooves 130 may have the same shape and area. Here, the cross-sections on the Y-Z plane of the second grooves 130 include virtual planes, and each of the virtual planes may have the same shape and area as the cross-section on the Y-Z plane of a material when the second groove 130 is filled with the material.
Various embodiments of cross-sections of the first groove 120 and the second groove 130 on the Y-Z plane are described below with reference to
According to embodiments, the width of each of the plurality of first grooves 120 and the second grooves 130 in the horizontal direction may be the same as each other. That is, the cross-sections of the first groove 120 and the second groove 130 on the X-Y plane may have the same width.
According to embodiments, at least one of the plurality of first grooves 120 and at least one of the plurality of second grooves 130 may overlap each other in the horizontal directions X and Y.
The cross-section on the X-Y plane of each of the plurality of first grooves 120 may have a spiral shape. For example, the cross-section on the X-Y plane of each of the plurality of first grooves 120 may have a spiral shape of which the radius gradually increases from the center of the body 110 toward the edge of the body 110. The plurality of first grooves 120 may be spaced apart from each other by a certain distance in the horizontal directions X and Y on the X-Y plane. Here, the cross-section on the X-Y plane of each of the plurality of first grooves 120 includes a virtual plane, and the virtual plane may be substantially the same as the cross-section on the X-Y plane of a material when each of the first grooves 120 is filled with the material.
The cross-section on the X-Y plane of each of the plurality of second grooves 130 may have a spiral shape. The plurality of second grooves 130 may be formed inside the body 110 and have a spiral cross-section on the X-Y plane inside the body 110. Here, the cross-section on the X-Y plane of each of the plurality of second grooves 130 includes a virtual plane, and the virtual plane may be substantially the same as the cross-section on the X-Y plane of a material when each of the second grooves 130 is filled with the material.
According to embodiments, the second grooves 130 may be formed through methods, such as 3D printing, molding, or laser cutting. The 3D printing may include fused deposition modeling (FDM), stereolithography (SLA), and digital light processing (DLP) methods.
In the chemical mechanical polishing pad 100 according to embodiments of the present disclosure, at least two of the first grooves 120 may have different depths, and at least two of the second grooves 130 formed inside the body 110 may have upper ends at different heights from each other. Accordingly, as the body 110 gradually wears down, the first grooves 120 do not disappear all at once but gradually disappear at least one by one. The second grooves 130 exposed from the body 110 upward in the vertical direction Z may also be exposed upward in the vertical direction Z at different times (e.g., one by one), rather than being simultaneously exposed upward from the body 110 in the vertical direction Z. Accordingly, the polishing slurry may be simultaneously provided into the first groove 120 and the second groove 130, which are formed in the body 110. Therefore, compared to the case in which the first grooves 120 disappear all at once and the second grooves 130 are fully exposed at once, a more constant amount of polishing slurry may remain in the chemical mechanical polishing pad 100 according to embodiments of the present disclosure.
For example, in a comparative embodiment, when the first grooves 120 disappear all at once and the second grooves 130 are exposed all at once, the volume of each of the first grooves 120 continues to decrease as the body 110 wears down. In addition, in the comparative embodiment, the second grooves 130 are not exposed in the vertical direction Z until all of the first grooves 120 disappear. Therefore, the volumes of the polishing slurry filling the chemical mechanical polishing pad 100 are gradually reduced. In addition, at the moment when all of the first grooves 120 disappear and all of the second grooves 130 are exposed, the volumes of the polishing slurry filling the chemical mechanical polishing pad 100 sharply increases. Accordingly, in a comparative embodiment, the polishing rate may change sharply during the polishing process.
However, in the chemical mechanical polishing pad 100 according to embodiments of the present disclosure, the first grooves 120 do not disappear at the same time, and the second grooves 130 may also be sequentially exposed in the vertical direction Z. Accordingly, the volume of the polishing slurry filling the chemical mechanical polishing pad 100 may be maintained relatively constant, and the polishing rate may also be maintained constant.
In addition, each of the first grooves 120 and the second grooves 130 of the chemical mechanical polishing pad 100 according to embodiments of the present disclosure may have a spiral cross-section on the X-Y plane. Accordingly, uniform pressure may be applied to the entire workpiece (e.g., a substrate) in contact with the chemical mechanical polishing pad 100. For example, when the polishing process is in progress, the workpiece may be pressed in the vertical direction Z by the chemical mechanical polishing pad 100. Here, the body 110 may be a main object, of the chemical mechanical polishing pad 100, that applies pressure to the workpiece. Although the first grooves 120 and the second grooves 130 are filled with the polishing slurry, the polishing slurry is usually provided as a fluid. Therefore, the pressure applied to the workpiece by the first grooves 120 and the second grooves 130 may be insignificant compared to the pressure applied to the workpiece by the body 110. Therefore, a workpiece is pressed by the body 110 in contact with the workpiece, and a portion of the body 110, in which the first grooves 120 and the second grooves 130 are not formed, may apply pressure to the workpiece.
Since each of the first grooves 120 and the second grooves 130 has a spiral shape on the cross-section of the X-Y plane, a portion of the body 110, excluding a region in which the first grooves 120 and second grooves 130 having the spiral cross-sections on the X-Y plane are formed, may apply pressure to the workpiece. Here, assuming that an arbitrary concentric circle is drawn on the chemical mechanical polishing pad 100 and the workpiece is brought into contact with the concentric circle, the above-described portion of the body 110 may have a relatively equal area no matter where the arbitrary concentric circle is drawn. Accordingly, no matter which part of the chemical mechanical polishing pad 100 the workpiece is brought into contact with, the workpiece may be in contact with the body 110 with the same area because each of the first grooves 120 and the second grooves 130 has the spiral cross-section on the X-Y plane. Accordingly, uniform pressure may be applied to the workpiece by the chemical mechanical polishing pad 100 during the polishing process.
Referring to
Referring back to the region BB of the body 110, the first grooves 121, 123, and 125 may be exposed from the body 110 in the vertical direction Z. Accordingly, the first grooves 121, 123, and 125 may be filled with the polishing slurry via the upper ends of the first grooves 121, 123, and 125. Also, the three second grooves 131, 133, and 135 may be arranged in the region BB of the body 110. The second grooves 131, 133, and 135 may be arranged inside the body 110 and have upper ends at different vertical levels from each other. The second grooves 131, 133, and 135 are all arranged inside the body 110, without being exposed to the outside, and may thus not be filled with the polishing slurry.
In
The second groove 131 having the highest vertical level among the second grooves 130 in the region BB of the body 110 may be exposed upward in the vertical direction Z due to wear of the body 110. According to embodiments, the total sum of the volume of the first groove 123 lost due to wear of the body 110 and the volumes of the first grooves 121-1 and 125-1 reduced due to the wear of the body 110 may be substantially equal to the volume of the second groove 131 exposed in the vertical direction Z due to the wear of the body 110. Accordingly, the chemical mechanical polishing pad 100 may accommodate the volume of polishing slurry that is substantially the same as the volume of polishing slurry that might be accommodated before the polishing process proceeds.
In
In the region BB of the body 110, the second groove 133 is exposed upward in the vertical direction Z due to wear of the body 110, and the volume of the second groove 131-1 may be less than the volume of the second groove 131 of
Therefore, even though the body 110 has worn down as the polishing process progresses, the volume of the polishing slurry contained in the chemical mechanical polishing pad 100 is maintained constant, and thus, the polishing rate may be maintained constant during the polishing process.
Referring to
Also, as shown in
Referring to
At least one second groove 130 is located below each of the first grooves 120, and thus, the second grooves 130 located below the first grooves 120 are exposed upward in the vertical direction Z due to wear of the body 110 even if the first grooves 120 disappear due to wear of the body 110. Accordingly, the volume of polishing slurry accommodated in the chemical mechanical polishing pad 101 may be maintained relatively constant.
While non-limiting example embodiments have been particularly shown and described in the present disclosure, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2023-0157687 | Nov 2023 | KR | national |
