Segmented Wire Cutting Support for Wafer Edge Quality
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Solution Overview
Problem
Current wire cutting technologies with bonded abrasives, particularly diamond wire cutting, face issues such as material tearing (chipping) at the edges of wafers, contamination of silicon powders, and difficulties in detecting the completion of cutting and separating wafers from the support, leading to reduced productivity and contamination during the recycling of silicon powders.
Innovation Solution
A support system for wire cutting that is composed of two different materials, where the first material is semiconductor silicon and the second material is chosen from epoxy resin, ceramic, or graphite, with a varying density and geometry to match the cutting difficulty of silicon, and includes longitudinal channels for cleaning fluids and witness parts to facilitate wire exit and cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a support made of material easier to cut than silicon is used, then wire cutting speed is improved, but material tearing (chipping) occurs at the edges of wafers
Solution Approach 1:
The support is segmented into multiple materials with different cutting resistances. The first material (e.g., silicon) has cutting resistance similar to the workpiece, while the second material (e.g., epoxy resin, ceramic, or graphite) has lower cutting resistance. This segmentation allows the wire to cut through the support at different speeds, improving overall cutting speed while maintaining wafer edge quality by using the harder first material at the cutting interface.
Solution Approach 2:
Different regions of the support have different material properties tailored to specific functions. The region in contact with the workpiece uses material with cutting resistance similar to silicon to prevent chipping, while other regions use easier-to-cut materials to improve wire penetration speed. This local differentiation of material properties resolves the contradiction between cutting speed and edge quality.
2Productivity
If the support material is easier to cut than silicon, then cutting efficiency is improved, but silicon powder contamination increases
Solution Approach 1:
The support is divided into materials that do not contaminate silicon powder. By using materials like epoxy resin, ceramic, or graphite instead of softer metals or composites that generate contamination, the system maintains high cutting efficiency while preventing silicon powder contamination. The first material (silicon or similar) and second material (non-contaminating) work together to achieve this.
Solution Approach 2:
The invention changes the material composition parameters of the support to eliminate contamination sources. By selecting materials with appropriate physical and chemical properties (hardness, bonding strength, chemical inertness), the support achieves both high cutting efficiency and minimal silicon powder contamination, enabling effective recycling of silicon powders.
3Ease of manufacture
If the support structure is simplified, then manufacturing cost is reduced, but detection of cutting completion and wafer separation becomes difficult
Solution Approach 1:
The support includes witness parts made of materials with different colors or optical properties. These witness parts serve as visual indicators of cutting progress and completion. The color difference between the first material (e.g., silicon-gray), second material (e.g., epoxy-resin colored), and workpiece allows easy visual detection of cutting completion and facilitates wafer separation without complicating the support structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution improves the surface quality of wafers by reducing chipping, increases productivity by ensuring timely wire exit and cutting completion detection, and minimizes silicon powder contamination, allowing for effective recycling and better cleaning of wafers.
Implementation Method 1
The cutting of the workpiece is made possible by the abrasion produced between the wire and the workpiece
Implementation Method 2
improves the surface quality of wafers by reducing chipping, increases productivity by ensuring timely wire exit and cutting completion detection, and minimizes silicon powder contamination, allowing for effective recycling and better cleaning of wafers
Data Source
Figure 1A~1C
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Figure 5~6
AI summary
The main object of the invention is a support (1) for cutting by bonded abrasive wire of at least one part to be cut made of a first material, characterized in that the support (1) is made by an assembly of different materials comprising at least the first material, the first material of the support (1) being distributed inhomogeneously with the other materials of the support (1).