Search

CN-121973049-A - Abrasive grain, abrasive block and grinding wheel for thinning wafer

CN121973049ACN 121973049 ACN121973049 ACN 121973049ACN-121973049-A

Abstract

The application relates to the technical field of integrated circuit manufacturing, and provides abrasive particles, abrasive blocks and grinding wheels for thinning a wafer. The preparation method of the composite nano coating comprises the steps of immersing abrasive particles into zirconium/cerium composite nano sol, drying to obtain sol coated abrasive particles, heating the sol coated abrasive particles to 450-550 ℃ and calcining for 2-4 hours to obtain the composite nano coating coated on the abrasive particle surfaces. Through the technical scheme, the problems of short service life of the grinding wheel and poor surface quality of the thinned wafer in the related technology are solved.

Inventors

  • ZHANG LIFEI
  • LU XINCHUN
  • ZHAO YING
  • ZHAO DEWEN

Assignees

  • 清华大学

Dates

Publication Date
20260505
Application Date
20251028

Claims (11)

  1. 1. The abrasive particles for thinning the wafer are characterized in that the surfaces of the abrasive particles are coated with a composite nano coating, and the components comprise cerium oxide and zirconium oxide; The preparation method of the composite nano coating comprises the following steps of immersing the abrasive particles into zirconium/cerium composite nano sol, drying to obtain sol coated abrasive particles, heating the sol coated abrasive particles to 450-550 ℃ and calcining for 2-4 hours to obtain the composite nano coating coated on the surface of the abrasive particles.
  2. 2. The abrasive particle for thinning the wafer according to claim 1, wherein the raw material of the composite nano coating comprises zirconium/cerium composite nano sol, and the zirconium/cerium composite nano sol comprises, by weight, 1-1.5 parts of an oxygen-containing zirconium source, 1.8-2.5 parts of an oxygen-containing cerium source and 2-3.5 parts of complexing acid.
  3. 3. The abrasive grain for thinning of a wafer according to claim 2, wherein the zirconium-containing source is zirconium nitrate, the cerium-containing source is cerium nitrate, and the cerium nitrate is cerium nitrate recovered from a cerium-containing polishing waste liquid by using ammonium nitrate as a recovery agent.
  4. 4. A wafer thinning abrasive block comprising the abrasive grain for wafer thinning according to any one of claims 1 to 3.
  5. 5. The wafer thinning abrasive according to claim 4, further comprising a ceramic matrix comprising silicon oxide, aluminum oxide, boron oxide.
  6. 6. Grinding wheel for wafer thinning, characterized by comprising: A wafer thinning abrasive block according to claim 4 or 5; The air holes are distributed in a multi-stage stacking manner and penetrate through the inside of the grinding block, each air hole consists of large air holes, medium air holes and small air holes with different particle sizes, the medium air holes are filled in gaps among the large air holes, and the small air holes are filled in the rest gaps to form a multi-stage pore system taking the large air holes as a main part.
  7. 7. The grinding wheel for thinning a wafer according to claim 6, wherein the raw materials of the grinding wheel comprise abrasive grains, polymer microspheres, ceramic bond sol and zirconium/cerium composite nano sol for coating the abrasive grains.
  8. 8. The grinding wheel for thinning a wafer according to claim 6, wherein the polymer microsphere is a polymer microsphere modified with a silane coupling agent.
  9. 9. The grinding wheel for thinning a wafer according to claim 7, wherein the polymer microspheres include first polymer microspheres having an average particle diameter of 100 to 110 μm, second polymer microspheres having an average particle diameter of 15 to 25 μm, and third polymer microspheres having an average particle diameter of 3 to 5 μm.
  10. 10. The grinding wheel for thinning the wafer according to claim 9, wherein the weight ratio of the first polymer microsphere to the second polymer microsphere to the third polymer microsphere is 3-4:2.5-3.5:2-3.
  11. 11. The grinding wheel for thinning the wafer according to claim 7, wherein the ceramic bond sol comprises, by weight, 28-32 parts of an oxygen-containing silicon source, 5-6.5 parts of an oxygen-containing aluminum source, 1.5-2 parts of an oxygen-containing boron source and 4-6 parts of a complexing acid.

Description

Abrasive grain, abrasive block and grinding wheel for thinning wafer The application is a divisional application of patent application of the application with the application number 2025115434798, which is filed on the day of 2025, 10 and 28. Technical Field The application relates to the technical field of integrated circuit manufacturing, in particular to abrasive particles, abrasive blocks and grinding wheels for wafer thinning. Background Three-dimensional integrated circuits (3D ICs) are an important technological path for the semiconductor industry to continue moore's law, improving chip performance and integration. The core idea is to stack a plurality of chips or functional layers in a vertical direction, and realize interlayer electrical connection Through-Silicon Via (TSV) and other interconnection technologies, so as to realize higher functional density in a limited space. Wafer thinning is a critical support process in 3D IC fabrication, the main purpose of which is to thin the wafer from the original thickness to an ultra-thin state suitable for vertical integration. Ultra-thin wafers are the physical basis for achieving 3D stacking and are critical to optimizing electrical performance and thermal management. As the number of stacked layers of 3D ICs increases, the demand for thickness reduction of individual wafers is becoming increasingly stringent. Meanwhile, 3D IC technology places extremely high demands on the surface quality of thinned wafers, including excellent total thickness bias (Total Thickness Variation, TTV) and extremely low surface roughness (Roughness Average, ra), to ensure accuracy, uniformity and stability of subsequent bonding processes. To achieve the above-mentioned thinning objective, the wafer thinning apparatus generally processes an ultrathin wafer by using a physical grinding action of a grinding wheel. The equipment has to precisely design and control the grinding structure and the grinding process, and can meet the processing requirements (such as thickness is less than or equal to 10 mu m, TTV is less than or equal to 1.5 mu m and Ra is less than or equal to 5 nm) of ultrathin wafers, and simultaneously, the manufacturing cost and the production efficiency are both considered. The wafer thinning grinding wheel is used as an important component in wafer thinning equipment, and the performance quality of the wafer thinning grinding wheel directly determines the surface quality of the thinned wafer. Ideally, the grinding wheel should meet three requirements simultaneously (1) proper elasticity is required to buffer the grinding stress, (2) sufficient rigidity is required to ensure the shape surface quality, and (3) excellent self-sharpening is also maintained to achieve stable grinding. However, the existing grinding wheel has poor mechanical property and low fracture toughness, and cannot bear the stress of high-speed grinding, so that the surface quality of the thinned wafer is poor. Disclosure of Invention The present application addresses, or at least alleviates, one or more of the above-identified problems and other problems of the prior art by providing abrasive particles, abrasive segments, and grinding wheels for wafer thinning. The technical scheme of the application is as follows: the application provides wafer thinning equipment, which comprises a grinding device and an adsorption platform, wherein the adsorption platform is used for supporting a wafer and driving the wafer to rotate; the grinding device is arranged above the adsorption platform in a lifting way, and the lower part of the grinding device is provided with a grinding wheel for grinding the wafer; The grinding wheel comprises a base material and a plurality of grinding blocks, and the grinding blocks are fixed on the base material through an adhesive layer; the abrasive brick comprises: a ceramic matrix; Abrasive particles distributed in the ceramic matrix; the composite nano coating is coated on the surface of the abrasive particles and used for enhancing the interface bonding strength of the abrasive particles and the ceramic matrix; The components of the composite nano coating comprise cerium oxide and zirconium oxide. As a further technical scheme, the raw materials of the composite nano coating comprise zirconium/cerium composite nano sol, wherein the zirconium/cerium composite nano sol comprises, by weight, 1-1.5 parts of an oxygen-containing zirconium source, 1.8-2.5 parts of an oxygen-containing cerium source and 2-3.5 parts of complexing acid. The method is characterized in that the oxygen-containing zirconium source is zirconium nitrate, the oxygen-containing cerium source is cerium nitrate, and the cerium nitrate is cerium nitrate recovered from cerium-containing grinding waste liquid by taking ammonium nitrate as a recovery agent. As a further technical scheme, the grinding wheel further comprises air holes distributed in a multi-stage stacking mode. As a further technical scheme,