Non-Contact Wafer Testing via Optical Symmetry Analysis
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Solution Overview
Problem
The existing methods for testing micro LEDs on wafers are time-consuming and risk damaging the micro LEDs due to physical contact, necessitating a more efficient and non-contact method to determine wafer quality in the epitaxial process.
Innovation Solution
A non-contact wafer testing method and system that uses incident light to generate a surface image of the wafer, analyzing symmetry and measurement ranges to quickly assess the quality of the wafer, thereby preventing damage and improving testing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a probe contacts the micro LED electrodes to test light emission, then the micro LED quality can be determined, but the testing time increases and the micro LED may be damaged
Solution Approach 1:
The patent replaces the mechanical contact testing method with an optical non-contact testing method. Instead of using a physical probe to contact the micro LED electrodes, the system uses light emission characteristics to determine micro LED quality. The wafer inspection system captures images of the wafer surface and analyzes light emission patterns, thereby eliminating mechanical contact while maintaining testing accuracy and significantly reducing testing time.
Solution Approach 2:
The patent creates an optical copy or image of the wafer surface to perform quality assessment. By capturing images of the wafer and analyzing the light emission patterns in these images, the system determines micro LED quality without physically interacting with the devices. This copying approach allows parallel processing of multiple micro LEDs simultaneously, reducing overall testing time.
2Reliability
If a probe contacts the micro LED electrodes to test light emission, then the micro LED quality can be determined, but the micro LED may be damaged
Solution Approach 1:
The patent replaces the mechanical contact testing method with an optical non-contact testing method. Instead of using a physical probe to contact the micro LED electrodes, the system uses light emission characteristics to determine micro LED quality. The wafer inspection system captures images of the wafer surface and analyzes light emission patterns, thereby eliminating mechanical contact while maintaining testing accuracy and significantly reducing testing time.
Solution Approach 2:
The patent introduces light as an intermediary medium to transfer information about micro LED quality. Rather than directly contacting the micro LED with a probe, the system uses light emission as a mediator to assess the functional status of the micro LEDs. This intermediary approach allows quality determination without applying mechanical stress or risk of damage to the delicate micro LED structures.
3Reliability
If individual micro LEDs are tested one by one or sampled, then quality can be assessed, but the testing efficiency decreases
Solution Approach 1:
The patent merges the testing of multiple micro LEDs into a single unified process. Instead of testing individual micro LEDs separately or using sampling methods, the system captures an image of the entire wafer and analyzes light emission patterns from all micro LEDs simultaneously. This merging approach maintains comprehensive quality assessment while dramatically improving testing efficiency by processing the entire wafer in one operation.
Solution Approach 2:
The patent transitions from one-dimensional individual testing to two-dimensional parallel testing by capturing the entire wafer surface in an image. This dimensional change allows simultaneous analysis of multiple micro LEDs across the wafer surface, transforming the testing process from sequential to parallel execution and thereby significantly enhancing productivity.
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 allows for rapid determination of wafer quality by examining symmetry in the surface image, enabling quicker adjustment of recipes and variables in subsequent processes without physical contact, thus speeding up the testing process and ensuring the quality of micro LEDs.
Implementation Method 1
a light emitting module is provided, to provide an incident light toward a wafer
Implementation Method 2
a light receiving module is provided, to receive light from the wafer, and to generate a wafer surface image corresponded to the wafer
Data Source
AI summary
Herein disclosed are a wafer, a wafer testing system, and a method thereof. Said wafer testing method comprises the following steps. First, an incident light is provided toward a wafer. And, a wafer surface image corresponded to the wafer is generated. Then, determining whether the wafer surface image has a plurality of first strips and a plurality of second strips, and the plurality of first strips and the plurality of second strips are symmetrical. When the wafer surface image has the plurality of first strips and the plurality of second strips, and the plurality of first strips and the plurality of second strips are symmetrical, a qualified signal corresponded to the wafer is provided.