BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic top view of a first conventional polishing pad having a surface pattern on the surface;
FIG. 2 is a schematic top view of a second conventional polishing pad having a surface pattern on the surface;
FIG. 3 is a schematic cross-sectional view of a polishing pad having hollow fibers according to the present invention;
FIG. 4 is diagram of an SEM photo of the hollow fibers used in the present invention;
FIG. 5 is a schematic cross-sectional view of a polishing pad having hollow fibers according to another embodiment of the present invention; and
FIGS. 6-7 are schematic views of a flow for fabricating the polishing pad having hollow fibers according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a polishing pad having hollow fibers, which is applied in a chemical mechanical polishing (CMP) process to polish or grind a workpiece to be ground. The workpiece to be ground may be, but is not limited to, a semiconductor, a storage medium substrate, an integrated circuit, an LCD flat panel glass, an optical glass or a photoelectric panel.
Referring to FIG. 3, it is a schematic cross-sectional view of a polishing pad having hollow fibers according to the present invention. The polishing pad 3 comprises a body 31 and a plurality of hollow fibers 32. The body 31 has a polishing surface 33. In this embodiment, the material of the body 31 is high solid PU, and the body 31 has a plurality of continuous or discontinuous holes 34 therein. However, the material of the body 31 also can be acryl resin or another resin.
FIG. 4, it is a diagram of an SEM photo of the hollow fibers used in the present invention. The hollow fibers used in the present invention are conventional hollow fibers. Referring to FIG. 3, the hollow fiber 32 is located within the body 31 and has an opening on the polishing surface 33, and the openings of the hollow fibers 32 are distributed uniformly. In this embodiment, the material of the hollow fibers 32 is selected from a group consisting of PP, PET, and Nylon. The ratio of the hollow area of the section of each of the hollow fibers 32 to the total area of the section thereof (hollowed ratio) is 10-30%.
In the present invention, the hollow area of the section of each hollow fiber 32 is larger than the sectional area of the polishing particles (not shown) in a polishing slurry, which allows the polishing slurry and polishing particles to flow within the hollow fibers 32. The polishing slurry and polishing particles thereby achieve a thorough circulation on the polishing pad 3 via the hollow fibers 32, unlike the transmission of the polishing slurry in the conventional polishing pad 1, 2 (FIG. 1 and FIG. 2), which is limited by the polishing area ratio occupied by the grooves. Moreover, in the present invention, since the flowability of the polishing slurry and polishing particles is superior, the processing time for the workpiece to be ground is uniform and can be estimated and controlled, unlike the processing time for the polishing slurry to be applied to the workpiece to be ground in the conventional polishing pad 1, 2 (FIG. 1 and FIG. 2), which cannot be estimated and controlled.
In this embodiment, the openings of the hollow fibers 32 are uniformly distributed, that is, the hollow fibers 32 are uniformly distributed on the polishing surface 33, and the hollow fibers 32 are vertical to the polishing surface 33. However, the openings of the hollow fibers 32 also can be arranged in a particular pattern, for example, arranged in a plurality of concentric circles, or arranged in a “#” shape.
Preferably, in other embodiment, the hollow fibers 32 further protrude from the polishing surface 33, as shown in FIG. 5. The effect of removing the residuals after the grinding process can be achieved in this embodiment by utilizing the toughness characteristic of the hollow fibers 32 themselves.
Preferably, the polishing pad 3 further comprises a plurality of grooves (not shown) located on the polishing surface 33. As seen from the top, the grooves can be a plurality of linear grooves arranged in “#” shape, or a plurality of concentric circular grooves.
The present invention further comprises a method for making the polishing pad 3, which comprises the following steps. First, a plurality of hollow fibers 32 as shown in FIG. 4 is provided. Then, referring to FIG. 6, the hollow fibers 32 are vertically arranged on a substrate 40. In this embodiment, the hollow fibers 32 are arranged on the substrate 40 by using electrostatic adsorption method. In this embodiment, the hollow fibers 32 are vertically distributed on the substrate 40 uniformly. However, the hollow fibers 32 can also be arranged into a particular pattern, for example, into a plurality of concentric circles, or into a “#” shape.
Next, referring to FIG. 7, a body 31 is formed to cover the hollow fibers 32. In this embodiment, the material of the body 31 is a High Solid PU, and the body 31 has a plurality of continuous or discontinuous holes 34 therein. However, the material of the body 31 also can be acryl resin or another resin.
Finally, the substrate 40 is removed, and the polishing pad 3 as shown in FIG. 3 is formed after overturning for 180 degrees.
While several embodiments of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention may not be limited to the particular forms as illustrated, and that all modifications which maintain the spirit and scope of the present invention are within the scope as defined in the appended claims.
Patent Application
20080064310
