Double-Disc Grinding Apparatus for Silicon Wafer Nanotopography Control
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Solution Overview
Problem
Conventional double-disc grinding methods struggle to maintain the nanotopography quality of silicon wafers, with the nanotopography level often exceeding 0.2 μm due to inadequate control over the workpiece holder's position along the axial direction of rotation, leading to degradation in the final product.
Innovation Solution
A double-disc grinding apparatus with a workpiece holder supported from the outer peripheral side, where the interval between the workpiece holder and static pressure support members is set to not greater than 50 μm, and the static pressure is maintained at not lower than 0.3 MPa, using a workpiece holder with parallelism and flatness of 5 μm or below, and grinding stones with diamond abrasive grains of 1 μm or below, to stabilize the workpiece holder position and suppress nanotopography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the interval between the workpiece holder and static pressure support members is increased, then the workpiece holder position stability improves, but the nanotopography quality deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the interval between the workpiece holder and static pressure support members to a specific range (5-50 μm) and setting the static pressure to a specific range (0.3-2.0 MPa). These parameter optimizations simultaneously achieve both workpiece holder position stability and nanotopography quality control, resolving the technical contradiction between stability and precision.
2Stability of the object's composition
If the static pressure is increased, then the workpiece holder position control improves, but the nanotopography degradation increases
Solution Approach 1:
The patent optimizes the static pressure parameter to a specific range (0.3-2.0 MPa) that simultaneously achieves workpiece holder position control and prevents nanotopography degradation. This parameter optimization resolves the contradiction by finding the optimal pressure level that provides sufficient support stability without causing excessive force on the workpiece.
3Device complexity
If conventional double-disc grinding is used, then the manufacturing process is simple, but the nanotopography level exceeds acceptable limits
Solution Approach 1:
The patent maintains the simplicity of conventional double-disc grinding while improving nanotopography control by optimizing specific parameters: the interval between workpiece holder and support members (5-50 μm) and static pressure (0.3-2.0 MPa). These parameter changes enable the process to meet stringent nanotopography requirements without increasing device complexity.
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
This configuration effectively stabilizes the workpiece holder position, significantly reducing nanotopography variations and improving the nanotopography level to meet recent demands, while allowing for high-quality grinding and reduced manufacturing costs.
Implementation Method 1
a pair of static pressure support members that are positioned on both sides of the workpiece holder and support the workpiece holder from both sides along an axial direction of the rotation thereof in a contactless manner based on a static pressure of a fluid
Implementation Method 2
a pair of grinding stones that simultaneously grind both surfaces of a workpiece supported by the workpiece holder
Data Source
AI summary
A workpiece double-disc grinding apparatus including a holder that supports a thin-plate-like workpiece from an outer periphery along a radial direction and is rotatable; a pair of static pressure support members that support the holder from both sides along an axial direction of the rotation thereof in a contactless manner based on a static fluid pressure; and a pair of grinding stones that simultaneously grind both surfaces of a workpiece supported by the holder, in which an interval between the holder and the static pressure support member is not greater than 50 μm, and the static pressure of the fluid that is not lower than 0.3 MPa. As a result, the workpiece double-disc grinding apparatus and a workpiece double-disc grinding method can stabilize a position of the holder, which can be a cause that degrades a nanotopography of the workpiece in the double-disc grinding for the workpiece.