Wafer Grinding Displacement Control for Thickness Uniformity
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Solution Overview
Problem
Existing methods for grinding semiconductor wafers result in significant variations in thickness, which are not adequately addressed by conventional techniques, leading to inefficiencies in the production of semiconductor devices.
Innovation Solution
A production apparatus and method that utilizes a rotating grindstone, a holding unit, and a displacement unit to displace the wafer in the rotation axis direction, allowing precise control of grinding amounts by using an air suction pipe and air bag to adjust the central and outer regions of the wafer independently, thereby reducing thickness variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional grinding methods are used to grind semiconductor wafers, then the wafer thickness can be reduced, but significant variations in thickness occur
Solution Approach 1:
The wafer back surface is divided into multiple regions (central region and outer regions) that are independently controllable. The air bag system allows separate displacement control of different wafer regions, enabling independent thickness adjustment for each zone to achieve uniform overall thickness
Solution Approach 2:
The system dynamically adjusts wafer position during the grinding process. The air suction pipe and air bag can independently displace the wafer back surface in real-time based on measured thickness variations, allowing continuous optimization of thickness uniformity during grinding
2Manufacturing precision
If the entire wafer is ground uniformly, then the grinding process is simple, but thickness variations cannot be corrected
Solution Approach 1:
The air bag system is divided into multiple independent air bags corresponding to different wafer regions. Each air bag can be independently controlled to displace specific areas of the wafer back surface, allowing localized thickness correction without complicating the overall grinding mechanism
Solution Approach 2:
The air suction pipe and air bag act as intermediary devices between the measurement system and the grinding process. They enable indirect control of wafer position by displacing the back surface, providing a simple mechanism to achieve precise thickness uniformity
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 method effectively reduces thickness variations by up to 1 μm, enhancing the uniformity of semiconductor wafers and improving the quality of semiconductor devices through controlled grinding and polishing processes.
Implementation Method 1
the air suction pipe holds the wafer by generating negative pressure, displacing a central region of the wafer in a rotation axis direction
Implementation Method 2
the air bag displaces an outer region of the wafer in the rotation axis direction when the air bag holds the wafer by generating positive pressure
Data Source
AI summary
A production apparatus includes: a rotating body configured to rotate a grindstone to cut a first surface of an object; a holding unit configured to contact a second surface of the object; and a displacement unit configured to displace at least a portion of the second surface of the object in a rotation axis direction of the rotating body.