Wafer Grinding Wheel With Angular Diamond Grains
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Solution Overview
Problem
The challenge in semiconductor processing is to grind silicon wafers thinner while preventing surface cracking, which existing grinding techniques struggle to achieve effectively due to inadequate control over grinding quality and surface integrity.
Innovation Solution
A grinding wheel with diamond abrasive grains of high aspect ratio and angular shape, mixed with a bonding material, is used to reduce contact area and shear stress, thereby enhancing grinding speed and preventing cracks, and the bonding material is designed to detach during grinding to maintain consistent grinding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional grinding techniques are used to grind silicon wafers thinner, then productivity is improved, but the risk of surface cracking increases
Solution Approach 1:
The grinding wheel uses diamond abrasive grains with specifically controlled local geometric properties (aspect ratio of 1:2.5 to 1:3.5, angular shape with grinding angles of 90° or less) to create localized optimal cutting conditions that reduce surface stress and prevent cracking while maintaining high grinding speed
Solution Approach 2:
The invention changes the geometric parameters of the abrasive grains (aspect ratio, angular shape, grinding angle) to optimize the cutting mechanism. These parameter changes enable the grains to cut more efficiently with reduced contact area and shear stress, thereby preventing surface cracking while improving productivity
2Manufacturing precision
If diamond abrasive grains with high aspect ratio and angular shape are used, then manufacturing precision is improved by reducing contact area and shear stress, but device complexity increases
Solution Approach 1:
The invention specifies precise geometric parameters for the diamond abrasive grains (aspect ratio of 1:2.5 to 1:3.5, angular shape with grinding angles of 90° or less) to optimize cutting performance. These controlled parameters reduce contact area and shear stress, improving grinding quality while the parameters themselves provide a clear manufacturing specification
3Productivity
If the bonding material is designed to detach during grinding, then productivity is improved through consistent grinding quality, but reliability of the grinding wheel structure decreases
Solution Approach 1:
The bonding material is intentionally designed to detach together with worn abrasive grains during the grinding process. This controlled discarding of bonding material maintains consistent grinding performance by exposing fresh abrasive grains, while the overall wheel structure remains intact and reliable
Solution Approach 2:
The bonding material's detachment characteristics are controlled through its physical and chemical parameters, enabling it to release abrasive grains at appropriate rates during grinding. This parameter control ensures consistent grinding quality while maintaining wheel structural integrity
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 grinding wheel effectively reduces the risk of cracking and improves grinding quality by minimizing contact area and shear stress, allowing for efficient processing of silicon wafers with increased strength and surface uniformity.
Implementation Method 1
A process of grinding an unnecessary rear portion of a wafer is performed before a package process in a semiconductor process. A silicon wafer may be subjected to rough grinding, fine grinding, and polishing.
Data Source
AI summary
A grinding wheel includes a plurality of wheel tips. The plurality of wheel tips include a plurality of diamond abrasive grains and a bonding material mixed with the diamond abrasive grains. The plurality of diamond abrasive grains have a ratio of a length in a long axis direction to a width in a short axis direction of 1:2.5 to 1:3.5 and includes edges or vertices having a grinding angle of 90° or less.