Semiconductor Light Extraction Surface Pattern Control
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Solution Overview
Problem
Conventional methods for forming uneven patterns on semiconductor light emitting devices using wet-etching with alkaline solutions result in irregular convex portions and require expensive equipment or lengthy processes, limiting the efficiency of light extraction.
Innovation Solution
A method involving the formation of pressed marks on the light extraction surface using a harder substrate with protrusions, followed by wet-etching with an alkaline solution, where the pressed marks act as etching masks to create desired convex portions with facets, allowing for controlled arrangement and increased height of the convex features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet-etching is applied to the light extraction surface using an alkaline solution, then etching treatment can be performed, but the convex portions become irregularly arranged due to dissolving erosion
Solution Approach 1:
The invention applies preliminary mechanical pressing to create pressed marks on the light extraction surface before etching. These pressed marks serve as pre-formed patterns that guide the subsequent etching process, ensuring that convex portions are formed in regular arrangements rather than irregular patterns from direct etching alone
Solution Approach 2:
The pressed marks act as an intermediary between the pressing process and the etching process. They transfer the pattern information from the mechanical pressing to the chemical etching, serving as a bridge that ensures regular arrangement of convex portions while maintaining the simplicity of wet-etching
2Manufacturing precision
If photolithography or nanoimprint method is used to form regular uneven patterns, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts and utilizes the pressed marks that are naturally formed during the manufacturing process as etching masks. Instead of adding complex photolithography or nanoimprint processes, it takes out and leverages the existing pressed marks to achieve regular convex portion arrangements, thereby simplifying the overall process
Solution Approach 2:
The pressed marks, which are byproducts of the pressing process, serve a dual function: they mark the positions for convex portions and act as etching masks. This self-service approach eliminates the need for separate mask formation processes, reducing device complexity while maintaining manufacturing precision
3Manufacturing precision
If multiple processes are used from mask formation to etching treatment, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The invention merges the mask formation function with the pressing process by utilizing the pressed marks as etching masks. This combination eliminates separate mask formation steps, reducing the number of processes from multiple steps (mask formation, etching) to integrated steps (pressing with mask function, etching), thereby improving productivity while maintaining precision
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 method enables the formation of convex portions in a desired arrangement, enhancing light extraction efficiency by increasing the effective area of the light extraction surface and simplifying the process compared to traditional techniques.
Implementation Method 1
applying wet-etching using an alkaline solution, to the surface of the nitride semiconductor layer
Data Source
AI summary
When an uneven pattern is formed on a light extraction surface composed of a semiconductor crystal by wet-etching using an alkaline solution, a plurality of convex portions cannot be formed in a desired arrangement. A method of manufacturing a semiconductor light emitting device includes a light extraction surface composed of a semiconductor crystal, wherein when the uneven pattern is formed by a plurality of convex portions on the light extraction surface, first, a plurality of impressions are formed on the light extraction surface of a semiconductor layer composed of a semiconductor crystal using a processing substrate, and next, by applying wet-etching to the light extraction surface using an alkaline solution, to thereby form convex portions with a portion where each impression is formed as a top portion, and a plurality of facets of the semiconductor crystal as a side face thereof.