Full Wafer Thickness Map Reflectometry for SOI Cleaving
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Solution Overview
Problem
The mechanical cleavage of silicon on insulator (SOI) wafers often results in non-uniform device layer thickness and can fail to cleave along the desired plane, leading to inefficiencies in the manufacturing process due to lack of timely feedback for process adjustments.
Innovation Solution
A thickness measuring system using an RGB camera and incoherent, uncollimated light sources to capture and produce thickness maps for semiconductor structures, allowing for real-time monitoring and adjustment of the cleaving process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical cleavage is used to separate bonded wafers, then the device layer can be formed, but non-uniform thickness and cleave failures occur
Solution Approach 1:
The patent implements real-time optical monitoring during the mechanical cleavage process to detect thickness variations and cleave propagation. This feedback mechanism allows for immediate detection of non-uniform thickness and potential cleave failures, enabling process adjustments to maintain manufacturing precision while using mechanical cleavage for ease of manufacture.
Solution Approach 2:
The patent replaces operator observation with an optical measurement system that uses light reflection and interference patterns to measure thickness. This substitution of mechanical/optical automation for manual inspection enables continuous real-time monitoring, resolving the contradiction between automated mechanical cleavage and precise thickness control.
2Device complexity
If operator observation is used to monitor cleave variations, then no additional equipment is needed, but timely feedback for process adjustment is not provided
Solution Approach 1:
The patent replaces manual operator observation with an automated optical measurement system that continuously monitors thickness during cleavage. This substitution eliminates the time delay associated with manual inspection and provides immediate feedback, resolving the contradiction between simple monitoring setup and timely process adjustment capability.
Solution Approach 2:
The optical measurement system operates continuously throughout the cleavage process, providing uninterrupted real-time data on thickness variations. This continuous monitoring enables immediate detection and response to process deviations, eliminating the intermittent nature of operator observation and reducing feedback time.
3Measurement precision
If conventional thickness measurement methods are used, then equipment is available, but real-time monitoring during cleaving is not achieved
Solution Approach 1:
The patent sets up the optical measurement system to monitor thickness before and during the cleavage process, allowing for predictive detection of potential failures and proactive process adjustments. This preliminary and continuous measurement approach maintains high measurement precision while enabling real-time monitoring that improves productivity by preventing defects rather than detecting them after the fact.
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
Enables accurate and timely thickness mapping of SOI wafers, improving the uniformity of the device layer and reducing the likelihood of cleaving failures by providing immediate feedback for process optimization.
Implementation Method 1
a camera positioned above a center of a semiconductor structure to capture light reflected by the semiconductor structure
Data Source
AI summary
A method of measuring a thickness of a semiconductor structure includes illuminating the semiconductor structure with the incoherent, uncollimated light from at least one light source, and capturing, using a camera, at least one image of the semiconductor structure illuminated by the light from the light source. The at least one image includes separate first color, second color, and third color images, the first, second, and third colors being different from each other. Thickness maps are produced for at least two layers of the semiconductor structure based on the first color, second color, and third color images and reference first color, second color, and third color images of a reference silicon wafer.