Laser Annealing Control for Cracked Semiconductor Substrates
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Solution Overview
Problem
The challenge in semiconductor manufacturing is that laser annealing can cause unnecessary heating and adhesion issues when cracks occur on the substrate, leading to reduced yield rates, as existing methods either discard cracked substrates or fail to prevent heating of unintended surfaces.
Innovation Solution
A method and apparatus that detect cracks on the substrate and control the laser annealing process to ensure a lower time integral of laser light exposure in the crack region compared to other areas, using an inspection unit, stage, optical unit, scanning section, and control unit to adjust the laser light scanning accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate is discarded when a crack is detected, then the adhesion problem between stage and substrate is avoided, but the yield rate is reduced
Solution Approach 1:
The patent applies local quality by making the laser irradiation selective - different regions of the substrate receive different amounts of laser energy based on crack detection. The control unit adjusts the laser light amount so that crack regions receive reduced irradiation while non-crack regions receive normal irradiation, allowing localized treatment rather than discarding the entire substrate.
Solution Approach 2:
The patent applies preliminary action by detecting cracks before laser annealing treatment and pre-planning the irradiation pattern. The inspection unit detects cracks in advance, and the control unit creates a treatment plan that avoids full irradiation of crack regions, preventing adhesion problems before they occur while preserving usable substrate areas.
2Productivity
If laser annealing is performed on a substrate with cracks, then the yield rate is maintained, but unnecessary heating and adhesion problems occur
Solution Approach 1:
The patent makes the laser irradiation spatially non-uniform by reducing the light amount in crack regions while maintaining normal irradiation in non-crack regions. This localized quality control ensures that heating occurs only where needed for annealing, preventing unnecessary heating in crack areas that would cause adhesion problems.
Solution Approach 2:
The patent implements feedback control by using inspection data from crack detection to dynamically adjust the laser irradiation parameters. The control unit receives crack location information and uses this feedback to modify the laser light amount in real-time, ensuring that irradiation is optimized based on the actual substrate condition.
3Ease of manufacture
If uniform laser irradiation is applied across the substrate, then the annealing process is simple, but crack regions experience excessive heating
Solution Approach 1:
The patent applies dynamics by making the laser irradiation parameters variable rather than static. The control unit dynamically adjusts the laser light amount based on the spatial location relative to detected cracks, creating a dynamic irradiation pattern that adapts to the substrate's actual condition while maintaining automated control.
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 approach allows for effective laser annealing on substrates with cracks while minimizing heating and adhesion problems, thereby maintaining yield rates and preventing unnecessary substrate discard.
Implementation Method 1
The laser annealing step being one of the manufacturing steps of the semiconductor device is a step of locally heating the semiconductor substrate using a laser to activate, for example, the semiconductor layer.
Implementation Method 2
an inspection unit configured to detect a crack generated on a main surface of a substrate
Data Source
AI summary
A crack generated on a main surface of a substrate is detected, and the main surface of the substrate is scanned with the laser light in order that a time integral of a light amount of laser light for annealing with which a unit area in a crack region including the detected crack is irradiated is smaller than a time integral of a light amount of the laser light with which a unit area in a region different from the crack region is irradiated, to perform laser annealing treatment on the substrate.