Nitride Semiconductor Metal Bump Formation via Selective Electroplating
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Solution Overview
Problem
Existing methods for forming nitride semiconductor light emitting elements with metal bumps face challenges in stabilizing thick bump formation and achieving flat metal layers, leading to potential leakage and reduced productivity.
Innovation Solution
A manufacturing method involving sequential steps such as protective layer formation, resist pattern creation, metal layer deposition, and electrolytic plating to form metal bumps, ensuring direct bonding of electrodes to the bumps without excessive metal layers, thereby enhancing reliability and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is laminated on the entire surface and then a resist pattern is formed with openings above electrodes, then metal bumps can be formed by electrolytic plating, but the process becomes complex and productivity decreases
Solution Approach 1:
The patent applies preliminary action by forming the metal layer only in specific regions before resist patterning, rather than laminating on the entire surface first. This preliminary selective formation of metal layers in electrode regions reduces subsequent processing steps and improves productivity while maintaining reliable metal bump formation.
2Manufacturing precision
If multiple metal layers are formed sequentially, then thick metal bumps can be achieved, but the number of manufacturing steps increases
Solution Approach 1:
The patent uses parameter changes by controlling the thickness and material composition of metal layers deposited in different regions, rather than forming multiple uniform layers across the entire surface. This allows precise control of metal bump thickness while reducing overall process complexity through selective deposition parameters.
3Area of stationary object
If a metal layer is formed on the entire surface, then complete coverage is achieved, but leakage prevention becomes difficult
Solution Approach 1:
The patent applies local quality by forming metal layers with different properties in different regions - specifically, forming metal layers only in electrode regions rather than uniform coverage. This localized metal layer formation prevents leakage between electrodes while providing complete coverage where electrically conductive, improving reliability without sacrificing necessary coverage.
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 improves the reliability and productivity of nitride semiconductor light emitting elements by reducing manufacturing steps, preventing leakage, and achieving thick, reliable metal bumps with high light extraction efficiency.
Implementation Method 1
a first metal layer that becomes an n-side electrode and a p-side electrode is formed on the n-side electrode connecting surface, the p-side electrode connecting surface and the first resist pattern without removing the first resist pattern. Subsequently, a second metal layer that becomes metal bumps is formed on the first metal layer by electrolytic plating
Data Source
AI summary
A manufacturing method of a flip-chip nitride semiconductor light emitting element includes a step of providing a nitride semiconductor light emitting element structure; a protective layer forming step; a first resist pattern forming step; a protective layer etching step; a first metal layer forming step; a first resist pattern removing step; a third metal layer forming step; a second resist pattern forming step; a second metal layer forming step; a second resist pattern removing step; and a third metal layer removing step.