Substrate Grinding Alignment for Uniform Wafer Flatness
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Solution Overview
Problem
Conventional grinding methods for semiconductor substrates fail to achieve uniform thickness due to non-uniform thickness distribution in the second substrate, especially when a metal film is present, leading to degraded flatness of the first substrate after grinding.
Innovation Solution
A substrate processing method that measures the thickness distribution of both substrates before and after grinding, adjusts the relative inclination of the substrate holder and grinder based on difference data to optimize the grinding process, and performs finishing grinding while accounting for device layer interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional grinding methods are used on combined substrates, then the grinding process can be completed, but the flatness of the first substrate deteriorates due to non-uniform thickness distribution in the second substrate
Solution Approach 1:
The patent measures the thickness distribution of the second substrate before bonding to the first substrate, and uses this information to pre-adjust the inclination of the substrate holder. This preliminary action compensates for non-uniform thickness distribution before the grinding process begins, preventing flatness deterioration during grinding.
Solution Approach 2:
The patent implements a feedback mechanism where the measured thickness distribution data of the second substrate is used to dynamically adjust the substrate holder inclination. The system continuously monitors and adjusts based on the actual thickness variations, ensuring uniform flatness of the first substrate after grinding.
2Manufacturing precision
If the substrate holder inclination is adjusted based on thickness distribution measurements, then the flatness of the first substrate is improved, but the device complexity increases due to additional measurement and adjustment mechanisms
Solution Approach 1:
The substrate holder is designed with multi-functionality, serving both as a support structure and as an adjustable inclination mechanism. The same holder that positions the substrate also provides the degree of freedom for inclination adjustment, eliminating the need for separate adjustment mechanisms and reducing overall device complexity.
Solution Approach 2:
The patent combines the thickness measurement function and the inclination adjustment function into an integrated system. The measurement data from the thickness distribution measurement is directly used to control the substrate holder inclination, merging the measurement and control functions into a unified process that reduces system complexity.
Data Source
AI summary
A substrate processing method includes measuring a first thickness distribution of a first substrate in a first one of multiple combined substrates before being subjected to a finishing grinding; measuring a second thickness distribution of the first substrate in a second one of the multiple combined substrates before being subjected to the finishing grinding; deciding a relative inclination between a substrate holder configured to hold the second one of the multiple combined substrates and a grinder configured to perform the finishing grinding on the corresponding combined substrate, based on first difference data between the first thickness distribution and the second thickness distribution; and performing finishing grinding on the first substrate in the second one of the multiple combined substrates while holding the second one of the multiple combined substrates at the inclination which is decided.