TWI841907B - Polishing pad, method for manufacturing polishing pad and polishing apparatus - Google Patents

Abstract

The present invention relates to a polishing pad including a polishing layer. The polishing layer includes a plurality of foaming pores, and a diameter of each of the foaming pores is 1 μm to 10 μm. The invention also relates to a method for manufacturing a polishing pad and a polishing apparatus.

Description

Polishing pad, method for manufacturing polishing pad, and polishing device

The present invention relates to a polishing pad with micro holes, a method for manufacturing the polishing pad and a polishing device.

Polishing generally refers to the wear control of the initially rough surface in the chemical-mechanical polishing (CMP) process, which uses a polishing slurry containing abrasive particles to be evenly dispersed on the upper surface of a polishing pad, and a substrate to be polished is pressed against the polishing pad and rubbed with repeated regular movements. The substrate to be polished is an object such as a semiconductor, a storage medium substrate, an integrated circuit, a liquid crystal display flat glass, an optical glass, and an optoelectronic panel. During the polishing process, a polishing pad must be used to polish the substrate to be polished, so the quality of the polishing pad will directly affect the polishing effect of the substrate to be polished.

In order to achieve a good polishing effect, the polishing pad may generally have a plurality of holes so that the polishing slurry can be contained in the holes. Referring to FIG. 1A and FIG. 1B, the top view and the cross-sectional enlarged view of the conventional polishing pad are shown respectively. The polishing pad has a plurality of holes, the opening size of which is about 100 μm and the depth can reach about 500 μm. Since the holes of the conventional polishing pad are relatively large, the impurities or agglomerated polishing particles and other residues generated during the polishing process are easily blocked in the holes, causing scratches on the surface of the substrate to be polished.

The present invention provides a polishing pad, comprising: A polishing layer having a plurality of foamed holes, and the diameter of each foamed hole is 1 μm to 10 μm.

The present invention also provides a method for manufacturing the aforementioned polishing pad, comprising: (a) providing a base layer; (b) forming a foaming resin on the base layer, the foaming resin comprising an abrasive layer and a fleece layer, the abrasive layer having a plurality of foaming holes, and the diameter of each foaming hole is 1 μm to 10 μm; and (c) removing the fleece layer.

The present invention also provides a polishing device, comprising: a polishing disc; a substrate to be polished; a polishing pad as mentioned above, which is attached to the polishing disc and used to polish the substrate to be polished; and a polishing slurry, which contacts the substrate to be polished for polishing.

The present invention provides a polishing pad, comprising: A polishing layer having a plurality of foamed holes, and the diameter of each foamed hole is 1 μm to 10 μm.

Please refer to Fig. 2A, which is a cross-sectional schematic diagram of a polishing pad 1 according to an embodiment of the present invention. The polishing pad 1 comprises a polishing layer 11 having a plurality of foamed holes 12, and the diameter of each foamed hole is 1 μm to 10 μm.

According to the present invention, the "polishing pad" refers to a pad used to support a substrate to be polished during the chemical mechanical polishing process. The polishing pad rubs the substrate to be polished with repeated regular movements and cooperates with a polishing slurry containing abrasive particles to wear the initially rough surface of the substrate to be polished to a smooth surface.

The polishing layer 11 of the present invention is a portion of the polishing pad used for rubbing the substrate to be polished. The polishing layer 11 has a plurality of foaming holes 12, and the diameter of each foaming hole 12 is 1 μm to 10 μm, preferably 1 μm to 8 μm, and more preferably 1 μm to 5 μm.

In detail, the material of the grinding layer 11 can be a foaming resin, and the foaming holes can be holes formed by the foaming resin. The term "foaming resin" mentioned in the present invention refers to a material containing a thermoplastic resin and a thermally decomposed foaming agent. The resin preferably includes at least one selected from the group consisting of: polyurethane, polyolefin, polycarbonate, polyvinyl alcohol, nylon, elastic rubber, polystyrene, polyaromatic molecules, fluoropolymers, polyimide, bridged polyurethane, bridged polyolefin, polyether, polyester, polyacrylate, elastic polyethylene, polytetrafluoroethylene, poly(ethylene terephthalate), polyaromatic amide, polyaromatic, polymethyl methacrylate, copolymers thereof, block copolymers thereof, mixtures thereof and blends thereof.

The foaming method of the foaming resin according to the present invention can be chemical foaming or physical foaming, wherein chemical foaming is to use a reagent that can undergo a chemical reaction to generate gas, and the gas generated after the reaction is evenly distributed in the resin composition. On the other hand, physical foaming is to inject gas into the resin composition and evenly distribute the injected gas in the resin composition by stirring.

As mentioned above, the foaming hole 12 can be a hole formed by the foaming resin, and the foaming hole 12 is preferably a connected hole. The "connected hole" mentioned in the present invention refers to at least two holes connected to form a hole similar to an ant hole. The hole is preferably a connected multi-hole hole, which is beneficial to the flow of the polishing liquid, the distribution of the polishing particles and the removal of the polishing residue.

Preferably, the material of the polishing layer 11 may be polyurethane, which may be formed by a wet process to adjust the hole diameter of the foamed hole 12 and to form interconnected holes.

On the other hand, preferably, the polishing layer 11 includes a polishing surface 13, and the foamed pores 12 are exposed on the polishing surface 13. The density of the foamed pores 12 on the polishing surface 13 is 15,000 pores/mm ² to 20,000 pores/mm ² .

In the polishing pad of the present invention, since the diameter of the foamed holes 12 of the polishing layer 11 is less than 10 μm, the impurities or agglomerated polishing particles and other residues generated during the polishing process are not easily blocked in the foamed holes 12, thereby avoiding scratches on the surface of the substrate to be polished. In addition, when the foamed holes 12 are interconnected holes, the circulation of the polishing liquid can be promoted to help discharge impurities or agglomerated polishing particles and other residues.

Please refer to FIG. 2B, which is a cross-sectional schematic diagram of a polishing pad 1b of another embodiment of the present invention. As shown in FIG. 2B, the polishing pad 1b is roughly similar to the polishing pad 1 in FIG. 2A, but the polishing pad 1b further includes a base layer 14, and the polishing layer 11 is attached to the base layer 14. The material of the base layer 14 can be a non-woven fabric, a non-woven fabric impregnated with polyurethane, or a polyethylene terephthalate film. In one embodiment, the base layer 14 can provide a buffering effect.

The term "nonwoven" as used herein refers to manufactured sheets, webs or felts of directional or randomly oriented fibers, which are held together by friction and/or cohesion and/or adhesion, and does not include paper and products that incorporate binding yarns or filaments that are knitted, knitted, tufted, sewn or bonded by wet milling (whether or not with additional needles). The fibers may be natural or artificial. They may be fixed-length or continuous filaments or may be formed in situ. Depending on the method of forming the web, nonwovens typically include synthetic nonwovens, needle-rolled nonwovens, meltblown nonwovens, spunbond nonwovens, dry-laid nonwovens, wet-laid nonwovens, sewed nonwovens or spunlace nonwovens. Compared with woven fabrics, non-woven fabrics have better material properties.

In a preferred specific embodiment of the present invention, the grinding layer 11 can be formed by using the base layer 14 as a carrier, and forming a foamed resin on the base layer 14, the foamed resin having the foamed holes 12, and then grinding or scraping the foamed resin surface to a certain thickness to form the grinding surface 13, and exposing the foamed holes 12 on the grinding surface 13, as described in detail below.

Figures 3A and 3B respectively show the top view and cross-sectional view of a polishing pad of an embodiment of the present invention under a scanning electron microscope (SEM) at 1,000 times magnification. As shown in Figures 3A and 3B, the maximum diameter of the foamed holes of the polishing pad of the present invention is about 6.40 μm, the minimum diameter is about 3.30 μm, the average diameter is about 4.11 μm, and the holes can be interconnected.

The present invention also provides a method for manufacturing the aforementioned polishing pad, comprising: (a) providing a base layer; (b) forming a foaming resin on the base layer, the foaming resin comprising an abrasive layer and a fleece layer, the abrasive layer having a plurality of foaming holes, and the diameter of each foaming hole is 1 μm to 10 μm; and (c) removing the fleece layer.

Please refer to FIGS. 4A to 4D , which are schematic diagrams of steps of a method for manufacturing the polishing pad 1 or the polishing pad 1 b according to an embodiment of the present invention.

FIG. 4A shows step (a) of providing a base layer 14. The material of the base layer 14 may be a non-woven fabric or a polyethylene terephthalate film as mentioned above, so it will not be described in detail here.

FIG4B shows step (b) of forming a foamed resin 3 on the base layer 14. The foamed resin 3 includes a grinding layer 31 and a fleece layer 34. The grinding layer 31 has a plurality of foamed holes 32, and the diameter of each foamed hole 32 is 1 μm to 10 μm. In step (b) of the method, the foamed resin 3 is preferably polyurethane and is formed by a wet method to adjust the hole diameter of the foamed hole 32 and form a connected hole. In addition, the material of the base layer 14 is preferably non-woven fabric. By adjusting the density, humidity, etc. of the non-woven fabric, the hole shape of the foamed resin 3 can be adjusted.

For example, step (b) of the method may include: (b1)   applying a solution containing the foaming resin on the base layer; (b2)   curing the foaming resin; (b3)   washing the cured foaming resin; and (b4)   drying the cured foaming resin.

In step (b1) of the method, a suitable solvent for the foaming resin 3 may include dimethylformamide (DMF). In addition to the solvent, the solution containing the foaming resin may optionally contain additives such as surfactants. In one embodiment, the concentration of the foaming resin in the solution containing the foaming resin is preferably in the range of 2 wt % to 60 wt %.

In step (b2) of the method, the base layer 14 and the foaming resin 3 may be placed in a curing solution for curing. The curing solution may contain about 45 wt% to about 70 wt% of dimethylformamide in water, preferably about 55 wt% to about 65 wt%, and more preferably about 60 wt%. Curing conditions are well known to those skilled in the art. Curing is preferably carried out at room temperature (about 25°C) and normal pressure (about 1 atmosphere), and soaking for about 1 hour to about 5 hours, preferably about 1 hour to about 5 hours, and more preferably about 3 hours. Since the solution containing the foaming resin is applied on the base layer 14 in step (b1), the foaming resin 3 is attached to the base layer 14 after curing in step (b2).

For example, in one embodiment of the present invention, a curing solution containing about 60 wt% of dimethylformamide in water is used and immersed for about 3 hours to form the foamed resin 3. The foamed resin 3 includes a grinding layer 31, and the diameter of the foamed holes 32 thereof is 1 μm to 10 μm, and the cross-sectional view of the grinding layer 31 magnified 2,600 times under a scanning electron microscope is shown in FIG4C.

In a preferred embodiment of the present invention, the method for manufacturing a polishing pad further comprises a washing step (b3) after step (b2). The purpose of washing is to remove residues from the base layer 14 and the foamed resin 3. In an embodiment of the present invention, washing is performed with water and, if necessary, an extrusion wheel is used. The washing conditions are well known to those skilled in the art. Preferably, the base layer 14 and the foamed resin 3 are washed in water at 50 to 90° C. and then subjected to an extrusion wheel several times.

In step (b4) of the method, the purpose of drying is to remove excess solvent (or wash water). Drying conditions are well known to those skilled in the art. In one embodiment of the present invention, drying is air drying, and the drying temperature is in the range of 100°C to 160°C.

According to the aforementioned wet method, as shown in FIG. 4B , a foamed resin 3 can be formed on the base layer 14, which includes a grinding layer 31 and a fleece layer 34 at the same time. Among them, the holes 341 of the fleece layer 34 are relatively large, so it must be removed in a subsequent step. The grinding layer 31 has tiny foamed holes 32, which are suitable for grinding purposes. Therefore, after removing the fleece layer 34 in step (c), the foamed resin 3 can be formed into a grinding layer 11 as shown in FIG. 2B , which has a grinding surface 13, and the foamed holes 12 are exposed on the grinding surface 13. Thereby, a grinding pad 1b as shown in FIG. 2B can be formed, which includes the grinding layer 11 and the base layer 14.

In step (c) of the method, the fleece layer 34 may be removed by mechanical grinding such as sandblasting. The conditions of mechanical grinding are well known to those skilled in the art. In one embodiment, step (c) of the method may include removing 1/10 to 1/2 of the thickness of the foamed resin to fully remove the fleece layer 34.

In addition, in one embodiment, as shown in FIG. 4D , step (c0) can be performed before step (c) to remove the base layer. Since the foaming resin 3 will gradually dry and increase the bonding force with the base layer 14, it is better to remove the base layer 14 after the foaming resin 3 is formed. Then, the fleece layer 34 is removed, and the foaming resin 3 is formed into a polishing layer 11 as shown in FIG. 2A , which has a polishing surface 13, and the foaming holes 12 are exposed on the polishing surface 13. Thereby, a polishing pad 1 as shown in FIG. 2A can be formed, which includes the polishing layer 11.

The present invention also provides a polishing device, comprising: a polishing disc; a substrate to be polished; a polishing pad as mentioned above, which is attached to the polishing disc and used to polish the substrate to be polished; and a polishing slurry, which contacts the substrate to be polished for polishing.

Referring to FIG. 5 , a schematic diagram of a polishing device having a polishing pad of the present invention is shown. The polishing device 5 includes a pressure plate 51, an adsorption pad 52, a substrate to be polished 53, a polishing disc 54, a polishing pad 55 and a polishing slurry 56, and the polishing pad 55 can be the polishing pad 1 or the polishing pad 1b as described above. The pressure plate 51 is opposite to the polishing disc 54. The adsorption pad 52 is adhered to the pressure plate 51 by a backing layer (not shown in the figure), and the adsorption pad 52 is used to adsorb and fix the substrate to be polished 53. The polishing pad 55 is fixed to the polishing disc 54 and faces the pressure plate 51 to polish the substrate to be polished 53.

The operation of the polishing device 5 is as follows. First, the substrate 53 to be polished is placed on the adsorption pad 52, and the substrate 53 to be polished is adsorbed by the adsorption pad 52. Then, the polishing disc 54 and the pressure plate 51 rotate in opposite directions, and at the same time, the pressure plate 51 is moved downward, so that the polishing pad 55 contacts the surface of the substrate 53 to be polished. By continuously replenishing the polishing slurry 56 and the polishing pad 55, the substrate 53 to be polished can be polished.

The above embodiments are only for illustrating the principle and effect of the present invention, but not for limiting the present invention. The modification and changes made to the above embodiments by a person with ordinary knowledge in the technical field to which the present invention belongs shall not violate the spirit of the present invention. The scope of the rights of the present invention shall be as listed in the scope of the patent application described below.

1: Grinding pad 1a: Grinding pad 11: Grinding layer 12: Foaming holes 13: Grinding surface 14: Base layer 3: Foaming resin 31: Grinding layer 32: Foaming holes 34: Fleece layer 341: Holes 5: Grinding device 51: Pressure plate 52: Adsorption pad 53: Substrate to be polished 54: Grinding disc 55: Grinding pad 56: Grinding slurry

FIG. 1A shows an enlarged top view of a conventional polishing pad.

FIG. 1B shows an enlarged cross-sectional view of a conventional polishing pad.

FIG. 2A is a schematic cross-sectional view of a polishing pad according to an embodiment of the present invention.

FIG. 2B is a schematic cross-sectional view of a polishing pad according to another embodiment of the present invention.

FIG. 3A is a top view of a polishing pad according to an embodiment of the present invention, magnified 1,000 times under a scanning electron microscope (SEM).

FIG. 3B is a cross-sectional view of a polishing pad according to an embodiment of the present invention at a magnification of 1,000 times under a scanning electron microscope (SEM).

FIG. 4A shows one or more steps of a method for manufacturing a polishing pad according to an embodiment of the present invention.

FIG. 4B shows one or more steps of a method for manufacturing a polishing pad according to an embodiment of the present invention.

FIG4C shows a cross-sectional view of the polishing layer of the foamed resin according to an embodiment of the present invention at a magnification of 2,600 times under a scanning electron microscope (SEM).

FIG. 4D shows one or more steps of a method for manufacturing a polishing pad according to an embodiment of the present invention.

FIG5 is a schematic cross-sectional view of a polishing device according to an embodiment of the present invention.

Claims (8)

A polishing pad comprises: a polishing layer having a polishing surface and a plurality of foamed holes, wherein the foamed holes are interconnected holes, each of which has a diameter of 1 μm to 10 μm, and a foamed hole density of the polishing surface is 15,000/mm ² to 20,000/mm ² . As in claim 1, the polishing pad, wherein the material of the polishing layer is polyurethane. The polishing pad as claimed in claim 1 further comprises a base layer, the polishing layer is attached to the base layer, and the material of the base layer is non-woven fabric or polyethylene terephthalate film. A method for manufacturing a polishing pad as claimed in any one of claims 1 to 3, comprising: (a) providing a base layer; (b) forming a foaming resin on the base layer, the foaming resin comprising an abrasive layer and a fleece layer, the abrasive layer having a plurality of foaming holes, and the diameter of each foaming hole is 1 μm to 10 μm; and (c) removing the fleece layer. The method of claim 4, wherein step (b) comprises forming the foaming resin by a wet process. The method of claim 4, wherein step (c) comprises removing 1/10 to 1/2 of the thickness of the foaming resin. The method of claim 4, wherein before step (c), it further comprises: (c0) removing the base layer. A polishing device comprises: a polishing disc; a substrate to be polished; a polishing pad according to any one of claims 1 to 3, which is attached to the polishing disc and used to polish the substrate to be polished; and a polishing slurry, which contacts the substrate to be polished for polishing.