Nitride Semiconductor Pad Electrode Wet Etching Process
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Solution Overview
Problem
The existing methods for manufacturing nitride semiconductor light emitting elements require a large number of steps, which hampers productivity and efficiency.
Innovation Solution
A method that reduces the number of steps by forming the pad electrode layer and protective layer using wet etching, where a metal multi-layered film with Cr, Ru, Ni, or Pd as the lowermost layer and Au as the upper layer is used, allowing for the pad electrodes to be formed in close contact with the overall electrode and n-type nitride semiconductor layer, and the protective layer is applied without removing the resist pattern, thereby simplifying the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pad electrode and protective layer are formed in independent different steps using conventional methods, then the manufacturing precision and reliability are maintained, but the number of manufacturing steps increases, reducing productivity
Solution Approach 1:
The patent combines the pad electrode formation and protective layer formation into a single integrated process step. The protective layer is formed to cover the entire surface including pad electrode regions, and subsequent patterning removes the protective layer from pad electrode areas to expose them. This merging of steps reduces the total number of manufacturing operations while maintaining the functional separation of pad electrodes and protective regions.
Solution Approach 2:
The protective layer is formed preliminarily over the entire surface before pad electrode exposure. This preliminary formation allows the protective layer to be deposited in one continuous process, and then selective removal is performed later to expose pad electrodes. This approach eliminates the need for precise alignment during protective layer deposition and reduces the number of separate formation steps.
2Manufacturing precision
If multiple resist patterns and etching steps are used to form pad electrodes and protective layers separately, then the manufacturing precision is maintained, but the manufacturing time and process complexity increase
Solution Approach 1:
The patent merges the patterning operations for pad electrodes and protective layer into a single resist pattern formation and etching sequence. The protective layer is patterned using one resist application and etching process, which simultaneously defines both the protective layer boundaries and the pad electrode exposure areas, eliminating the need for separate resist patterns and alignment steps.
Solution Approach 2:
The single resist pattern serves multiple functions: it defines the boundaries of the protective layer, identifies areas where the protective layer should be removed to expose pad electrodes, and guides the etching process to achieve both protective layer formation and pad electrode exposure in one operation. This multi-functional resist pattern reduces the number of sequential steps required.
3Reliability
If conventional multi-step processes are used for forming pad electrodes and protective layers, then the reliability of pad electrode adhesion is maintained, but the number of process steps increases, affecting productivity
Solution Approach 1:
The patent combines pad electrode formation and protective layer formation into one integrated process flow. The protective layer is deposited over the entire surface in one step, and subsequent selective removal exposes pad electrodes that were formed in close contact with the underlying structure. This merging maintains adhesion reliability by avoiding multiple handling and deposition cycles while improving throughput.
Solution Approach 2:
The protective layer is formed preliminarily over the pad electrode areas before final exposure. This preliminary coverage allows the pad electrodes to be formed with proper adhesion to the underlying nitride semiconductor layer and overall electrode in one continuous process, without requiring separate adhesion promotion steps that would increase process complexity.
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 enhances productivity by reducing the manufacturing steps, ensuring high reliability and low peeling rates of the pad electrodes while minimizing damage to the nitride semiconductor light emitting element structure, thereby improving the overall efficiency and adhesiveness of the nitride semiconductor light emitting elements.
Implementation Method 1
A pad electrode layer forming step, a resist pattern forming step, a pad electrode layer etching step, a protective layer forming step and a resist pattern removing step are sequentially performed
Data Source
AI summary
To provide a method of manufacturing a nitride semiconductor light emitting element, which has a small number of steps and thus, can improve productivity, the method of manufacturing a nitride semiconductor light emitting element including a nitride semiconductor light emitting element structure having an n-type nitride semiconductor layer and a p-side nitride semiconductor layer which are laminated on a substrate, an n-side pad electrode connecting surface and a p-side pad electrode connecting surface which are formed on the same plane of the substrate; a n-side pad electrode on the n-side pad electrode connecting surface; and a p-side pad electrode on the p-side pad electrode connecting surface, and in the manufacturing method, a pad electrode layer forming step, a resist pattern forming step, a pad electrode layer etching step, a protective layer forming step and a resist pattern removing step are sequentially performed.