Semiconductor Light Emitting Device Cleavage via Dummy Pattern Guidance
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Solution Overview
Problem
In semiconductor light-emitting devices, irregularities in the end surface due to cleavage deviations cause differences in level that can overlap with the light-emitting unit, affecting light-emitting properties and reliability.
Innovation Solution
The method involves forming dummy patterns on the wafer apart from the light-emitting units, where cleavage offset occurs, and using these patterns to guide the cleavage direction, ensuring that differences in level are prevented from overlapping the light-emitting unit by forming a laminated structure with light-emitting units, electrode patterns, and dummy patterns, and cleaving along the orientation from the dummy patterns toward the light-emitting units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If cleavage is performed on a single-crystal wafer with thin films grown on it, then flat mirror surfaces are obtained on the end surfaces, but the normal development of cleavage is interfered and difference in level occurs on the end surface
Solution Approach 1:
A groove is formed in advance at a position deeper than the thin films on the single-crystal wafer, before the cleavage process. This preliminary groove structure guides the cleavage to occur at a controlled location, preventing the cleavage front from deviating due to interference from the thin films, thereby eliminating difference in level on the end surface while maintaining the flat mirror surface quality
2Reliability
If electrode patterns are formed on the wafer, then conduction is achieved, but the cleavage may contact the electrode pattern causing difference in level to overlap the light-emitting unit
Solution Approach 1:
The groove is preliminarily formed at a specific position that is deeper than the thin films and strategically located to intercept the cleavage front before it can contact the electrode patterns. This preliminary groove structure ensures that even if electrode patterns are formed on the wafer, the cleavage will follow the groove path and not deviate to contact the electrode patterns, preventing difference in level from overlapping the light-emitting unit while maintaining conduction reliability
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 effectively prevents differences in level from overlapping the light-emitting unit on the end surface, ensuring improved light-emitting properties and reliability by correctly aligning the cleavage direction with the dummy patterns.
Implementation Method 1
a scratch is formed on a single-crystal wafer on which a laminated structure having light-emitting units is formed and electrode patterns and dummy patterns are formed; the single-crystal wafer is cleaved to originate on the scratch along a cleavage orientation
Data Source
AI summary
A laminated structure having light-emitting units is formed on a single-crystal wafer. Electrode patterns are formed on the single-crystal wafer opposite the light-emitting units. Dummy patterns are formed on the single-crystal wafer at a location spaced apart from a location opposite the light-emitting units, and offset from a desired cleavage line intersecting the light-emitting units. A scratch is formed on the desired cleavage line. The wafer is cleaved, originating on the scratch, along the cleavage line orientation, in the direction from the dummy pattern, toward the light-emitting units.