CN-122008020-A - Grinding structure, preparation method and grinding wheel for thinning wafer

CN122008020ACN 122008020 ACN122008020 ACN 122008020ACN-122008020-A

Abstract

The application discloses a grinding structure, a preparation method and a grinding wheel for thinning a wafer, wherein the grinding structure comprises a flexible combination body and a plurality of first rigid microstructures, the first rigid microstructures are arranged in the flexible combination body in a three-dimensional mode at intervals and are stacked in the feeding direction of the grinding structure, and the interval spaces among the first rigid microstructures are filled by the flexible combination body. The thinning method adopts wafer thinning equipment and comprises the step of simultaneously improving the feeding speed and the rotating speed of the grinding wheel. When the wafer is ground and thinned, the grinding efficiency can be improved, the surface damage of the wafer can be reduced, the surface roughness of the wafer is reduced, the surface of the wafer is smoother, and the high-precision integration requirement of the core particle is met.

Inventors

ZHANG LIFEI
LU XINCHUN
XING YI
ZHAO DEWEN

Assignees

清华大学

Dates

Publication Date: 20260512
Application Date: 20251028

Claims (14)

1. A grinding structure for thinning a wafer, characterized by comprising a flexible bond and a plurality of first rigid microstructures, wherein the plurality of first rigid microstructures are arranged in the flexible bond in a three-dimensional manner at intervals and stacked in a feeding direction of the grinding structure, and the interval spaces among the plurality of first rigid microstructures are filled by the flexible bond; The grinding structure comprises a plurality of composite grinding layers which are stacked along the feeding direction, each composite grinding layer comprises a flexible bonding layer and a plurality of first rigid microstructures which are distributed in the flexible bonding layer at intervals, and the flexible bonding layers of the composite grinding layers are bonded to form the flexible bonding body; the first rigid microstructure comprises a rigid sheet of rigid material.
2. The grinding structure of claim 1, characterized by comprising at least one of the following features 1) -4): 1) The two adjacent first rigid microstructures in the feeding direction are staggered and stacked; 2) The width of the first rigid microstructure in the vertical direction of the feeding direction is 20-30 mu m; 3) The width of the interval between two adjacent first rigid microstructures in the feeding direction is 10-20 microns, and the width of the interval between two adjacent first rigid microstructures in the vertical direction in the feeding direction is 5-10 microns; 4) The first rigid microstructure has a face portion and an edge portion, the face portion having an opposite charge from at least a portion of the edge portion.
3. The grinding structure of claim 1, wherein, The first rigid microstructure is sheet-like.
4. The grinding structure of claim 1, wherein, The rigid sheet body is a lamellar mineral sheet, a graphene oxide sheet, a hexagonal boron nitride sheet and/or a molybdenum disulfide sheet.
5. The grinding structure of claim 1, wherein, The first rigid microstructure further comprises a molecular interface modification layer formed by an anionic high molecular polymer, and the molecular interface modification layer is positioned on the surface of the rigid sheet body.
6. The grinding structure of claim 5, wherein, The first rigid microstructure further comprises a nano-reinforcing layer formed by nano-particles, wherein the nano-reinforcing layer is positioned on the surface of the molecular interface modification layer and/or the surface of the rigid sheet body.
7. The grinding structure of claim 6, wherein, The material of the nano particles is silicon dioxide, aluminum oxide, nano zirconium oxide, titanium carbide, amorphous calcium carbonate or hydroxyapatite; The particle size of the nano particles is 100 nm-200 nm.
8. A grinding structure according to claim 1 to 3, characterized in that, The grinding structure further comprises a plurality of second rigid microstructures, and the plurality of second rigid microstructures are dispersed in the flexible combination; the second rigid microstructure includes abrasive particles.
9. A grinding structure according to claim 1 to 3, characterized in that, The flexible combination body is made of polyimide resin, polyurethane, polyimide resin, epoxy resin or silicone rubber.
10. A method of manufacturing a grinding structure according to any one of claims 1 to 9, comprising the steps of: preparing a coating liquid, namely dispersing a plurality of first rigid microstructures in a bonding agent; Coating, curing and forming, namely coating a layer of coating liquid by a slit, dispersing a plurality of first rigid microstructures in a layer of bonding agent until the layer of bonding agent is cured to form a flexible bonding layer, forming a composite grinding layer by matching the flexible bonding layer with the plurality of first rigid microstructures, coating and forming the next composite grinding layer on the composite grinding layer, and repeating the steps until a plurality of layers of composite grinding layers are laminated to form the grinding structure.
11. The method of manufacturing a grinding structure of claim 10, further comprising the step of manufacturing a plurality of said first rigid microstructures, comprising the steps of: preparing a plurality of rigid sheets; preparing saturated aqueous solution of anionic high molecular polymer; placing each rigid sheet body in the saturated aqueous solution for molecular interface modification, so that the anionic high molecular polymer forms a molecular interface modification layer on the surface of each rigid sheet body, and the charge of the face part of the first rigid microstructure is opposite to the local charge of the edge part of the first rigid microstructure; In the coating, curing and forming step, the first rigid microstructures of two adjacent composite grinding layers can be stacked in a staggered manner through the action of electrostatic attraction.
12. The method of manufacturing a grinding structure of claim 11, wherein said preparing a plurality of said first rigid microstructures further comprises: And mixing each rigid sheet body with the molecular interface modification layer with nano particles to form a nano reinforcing layer on the surface of the rigid sheet body and the surface of the molecular interface modification layer by the nano particles.
13. The method of preparing a grinding structure of claim 10 wherein said formulating a coating solution further comprises dispersing abrasive particles in said binder.
14. A grinding wheel for thinning a wafer, characterized by comprising a grinding wheel base and a plurality of grinding structures according to any one of claims 1 to 9, a plurality of the grinding structures being fixed to the grinding wheel base by an adhesive layer; the grinding structures are arranged at intervals along the circumferential direction of the grinding wheel matrix.

Description

Grinding structure, preparation method and grinding wheel for thinning wafer The application is a divisional application of patent application of the application with the application number 2025115509690, which is filed on the day of 2025, 10 and 28. Technical Field The application relates to the technical field of semiconductor grinding, in particular to a grinding structure, a preparation method and a grinding wheel for thinning a wafer. Background With the rapid development of the semiconductor industry towards high-density integration and high-performance packaging, the core (Chiplet) integration technology has become one of core paths breaking through the bottleneck of the moore's law by virtue of the advantages of flexible combination, cost optimization, performance improvement and the like. Under the technical framework, the wafer thinning is used as a key process link, and the processing quality of the wafer thinning directly influences the heat dissipation performance, the packaging thickness and the bonding reliability of the chip. By precisely removing the redundant material on the back of the wafer, the wafer thinning process can remarkably reduce signal transmission delay, reduce packaging volume and provide basic support for multi-chip stacking, so that strict requirements are placed on the processing precision, surface quality and processing efficiency of wafer thinning, wherein thickness uniformity, namely total thickness deviation (Total Thickness Variation, TTV) is required to be controlled at a micrometer level or even a nanometer level, and the surface is required to be free from scratches and subsurface damage. Currently, grinding wheel grinding becomes one of the main processes of wafer thinning by virtue of the high efficiency advantage, and material removal is realized by a grinding wheel rotating at a high speed. However, the core challenge faced by this process is the stress concentration phenomenon during operation of the grinding wheel, which is particularly pronounced under high speed rotation and heavy duty machining conditions. Stress concentration not only can initiate initiation and expansion of microscopic cracks in the grinding wheel, increase the risk of sudden fracture, but also affect the processing quality of the wafer, fundamentally restrict the working stability of the grinding wheel and the processing precision of wafer thinning, and become main bottlenecks for improving the reliability of Chiplet integration technology. In the prior art, the stress concentration can be reduced by reducing the grinding depth and increasing the rotating speed of the grinding wheel, but the Material Removal Rate (MRR) is reduced, so that the service life of the grinding wheel is shortened. Therefore, the service life and the processing efficiency of the grinding wheel are required to be considered on the premise of ensuring the processing quality. Disclosure of Invention The application aims to provide a grinding structure, a preparation method and a grinding wheel for wafer thinning, which are used for solving the technical problems that the existing grinding wheel is easy to cause stress concentration phenomenon when the wafer is thinned, so that the grinding wheel works unstably and the processing precision of the wafer thinning is limited. The above object of the present application can be achieved by the following technical solutions: The application provides wafer thinning equipment, which comprises a grinding wheel, wherein the grinding wheel is arranged on a grinding shaft of the wafer thinning equipment, the grinding wheel comprises a grinding wheel matrix and a plurality of grinding structures, the plurality of grinding structures are fixed on the grinding wheel matrix through adhesive layers, the grinding structures comprise flexible combination bodies and a plurality of first rigid microstructures, the plurality of first rigid microstructures are arranged in the flexible combination bodies in a three-dimensional mode at intervals and stacked in the feeding direction of the grinding structures, and the interval spaces among the plurality of first rigid microstructures are filled by the flexible combination bodies. In an embodiment of the present application, the grinding structure includes a plurality of composite grinding layers stacked along the feeding direction, each of the composite grinding layers includes a flexible bonding layer and a plurality of first rigid microstructures distributed in the flexible bonding layer at intervals, and the flexible bonding layers of each of the composite grinding layers are bonded to form the flexible bonded body. In an embodiment of the present application, two adjacent first rigid microstructures in the feeding direction are stacked in a staggered manner. In an embodiment of the present application, a width of the first rigid microstructure in a direction perpendicular to the feeding direction is 20 μm to 30 μm. In the embodiment of