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CN-121973091-A - Grinding pad for improving uniformity of wafer edge and preparation method and application thereof

CN121973091ACN 121973091 ACN121973091 ACN 121973091ACN-121973091-A

Abstract

The invention belongs to the technical field of wafer manufacturing, and relates to a polishing pad for improving uniformity of a wafer edge, a preparation method and application thereof. The preparation method comprises the steps of uniformly coating an adhesive on one side surface of a grinding layer, attaching a buffer layer made of foaming polyurethane, and drying to obtain the grinding pad. The polishing pad provided by the invention adopts the foaming polyurethane as the buffer layer, overcomes the defects of the traditional non-woven fabric, and simultaneously adopts the adhesive to attach the polishing layer and the buffer layer, so that the influence of the adhesive layer on the deformation characteristic of the buffer layer is considered, and the edge uniformity of the wafer is effectively improved.

Inventors

  • HUANG KE
  • ZHENG RUILIN

Assignees

  • 沐科恒益(江苏)电子制造有限责任公司

Dates

Publication Date
20260505
Application Date
20260323

Claims (10)

  1. 1. The utility model provides an improve polishing pad of wafer edge degree of consistency, includes the grinding layer and the buffer layer of range upon range of setting, its characterized in that, the material of buffer layer is foaming polyurethane, just laminate each other through the adhesive between the grinding layer and the buffer layer.
  2. 2. The polishing pad of claim 1, wherein the buffer layer has a compression ratio of 9% -16%.
  3. 3. The polishing pad of claim 2, wherein the buffer layer has a compression ratio of 9% -12%.
  4. 4. The polishing pad of any one of claims 1-3, wherein the buffer layer has a porosity of 45% -55%.
  5. 5. The polishing pad of claim 4, wherein the buffer layer has a porosity of 45% -50%.
  6. 6. The polishing pad of claim 5, wherein the buffer layer has uniformly distributed internal voids in the horizontal direction.
  7. 7. The polishing pad of any one of claims 1-3, wherein the buffer layer has a thickness of 3-63 mils.
  8. 8. The polishing pad for improving uniformity of an edge of a wafer according to any one of claims 1 to 3, wherein the adhesive comprises at least one of epoxy, polyurethane, acrylate, or phenolic.
  9. 9. A method for preparing the polishing pad according to any one of claims 1 to 8, wherein the method comprises uniformly coating an adhesive on one side surface of a polishing layer, attaching a buffer layer made of foamed polyurethane, and drying to obtain the polishing pad.
  10. 10. Use of a polishing pad according to any one of claims 1 to 8, in a chemical mechanical polishing line for semiconductor wafers.

Description

Grinding pad for improving uniformity of wafer edge and preparation method and application thereof Technical Field The invention belongs to the technical field of wafer manufacturing, relates to a polishing pad for improving the uniformity of a wafer edge, and particularly relates to a polishing pad for improving the uniformity of the wafer edge, and a preparation method and application thereof. Background Chemical Mechanical Polishing (CMP) is a key process for realizing global planarization of a wafer in a semiconductor wafer manufacturing process, the polishing effect directly determines the surface quality of the wafer and the yield of subsequent chip manufacturing processes, the polishing uniformity of an edge area of the wafer is an important quality control point, the edge uniformity deviation can cause the failure of the edge chip of the wafer, the effective utilization rate of the wafer is greatly reduced, and therefore, the industry has strict requirements on the uniformity control capability of a CMP polishing pad. In the prior art, commercial CMP polishing pads generally adopt a double-layer structure with a polishing layer and a buffer layer combined, and the two layers are separated clearly. The polishing layer directly performs polishing action with the wafer, the material and the surface structure of the polishing layer determine the polishing rate of the wafer, the polishing layer belongs to a core functional layer of the polishing pad, the buffer layer mainly plays roles of uniformly distributing pressure and absorbing vibration, contact pressure distribution in the polishing process is regulated through self deformation characteristics, and the polishing layer belongs to a key structural layer for controlling the polishing uniformity of the wafer. At present, the mainstream buffer layer is mostly prepared by adopting non-woven fabrics, and the material is a universal choice for industry because of mature processing technology and low cost, but has inherent defects, and is difficult to meet the high-precision wafer edge uniformity requirement. Firstly, the non-woven fabric has strong water absorption, the polishing solution containing moisture can be continuously used in the CMP polishing process, the buffer layer can obviously expand after absorbing the polishing solution, the overall thickness of the polishing pad is continuously changed along with the polishing process, the surface is irregularly fluctuated, the stability of polishing pressure is damaged, and the inconsistent polishing quantity of each area of the wafer is directly caused. Secondly, the non-woven fabric is softer in texture, the compression ratio is generally in a higher range of 14% -20%, the deformation amount is larger, and in order to prevent the wafer from sliding in the polishing process, a positioning ring is arranged to apply continuous limiting pressure to the polishing pad, the pressure can enable the buffer layer to generate obvious local deformation, irregular fluctuation of polishing contact pressure of the edge area of the wafer is caused, or insufficient edge polishing is caused, or excessive edge polishing is caused, and finally the problem that the polishing non-uniformity of the wafer is maintained at a level of 4.5% -5% and the edge uniformity is poor is outstanding. In addition, the laminating of current grinding layer and buffer layer adopts the double faced adhesive tape to realize more, and though the simple operation, not enough with the cohesion of buffer layer, mechanical vibration and pressure in the polishing process easily lead to both layering for grinding pad structural stability is impaired, further aggravates polishing uniformity deviation. If the adhesive type is replaced, the influence of the adhesive layer on the deformation characteristics of the buffer layer is considered, and no adaptive adhesive scheme is found in the industry. Therefore, how to provide a polishing pad for improving the uniformity of the wafer edge, overcomes the defects of the existing non-woven fabric buffer layer, and simultaneously combines the influence of the adhesive layer on the deformation characteristics of the buffer layer, thus becoming a problem to be solved by those skilled in the art. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a polishing pad for improving the uniformity of the edge of a wafer, and a preparation method and application thereof, so that the defects existing in the existing non-woven fabric buffer layer are overcome, and meanwhile, the influence of a glue layer on the deformation characteristic of the buffer layer is considered. In order to achieve the aim of the invention, the invention adopts the following technical scheme: In a first aspect, the present invention provides a polishing pad for improving uniformity of a wafer edge, including a polishing layer and a buffer layer stacked together, where the buffer layer is made