Semiconductor Light-Emitting Lens Alignment via Backside Exposure
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Solution Overview
Problem
The existing method for aligning current injection regions and lenses in semiconductor light-emitting devices, such as VCSELs, is prone to misalignment due to refractive index differences between substrates and air, leading to potential deterioration in threshold values and yield, and requires costly exposure devices with limited accuracy.
Innovation Solution
A method involving a light-blocking structure on the substrate's surface, where a photosensitive layer is formed on the opposite side and patterned using light to create a lens that matches the light-blocking structure's shape, allowing for precise alignment and lens formation without the need for substrate alignment during exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If alignment marks on the substrate and photomask are overlapped through the substrate for exposure, then the current injection region and photomask can be aligned, but misalignment occurs due to refractive index difference between substrate and air
Solution Approach 1:
A photosensitive layer is introduced as an intermediary medium between the substrate and photomask. This layer is applied on the back surface of the substrate and exposed through the substrate, allowing the exposure pattern to be transferred accurately without being affected by refractive index differences at the air-substrate interface. The photosensitive layer acts as a mediator that receives the exposure pattern directly on the substrate surface, eliminating alignment errors caused by optical path differences.
2Ease of manufacture
If exposure is performed through the substrate to pattern the photosensitive member, then the lens can be formed on the substrate, but measurement errors increase and development delays occur
Solution Approach 1:
The photosensitive layer serves as an intermediary that enables direct patterning on the substrate without requiring precise measurement through the substrate. By applying the photosensitive layer on the back surface and exposing through the substrate, the pattern is transferred directly to the photosensitive layer, which then forms the lens structure. This eliminates the need for complex measurements through the substrate, reducing measurement errors and accelerating development.
3Manufacturing precision
If a photomask is used for exposure, then the photosensitive member can be patterned, but the process requires costly exposure devices with limited accuracy support
Solution Approach 1:
The photosensitive layer applied directly on the substrate back surface acts as an intermediary that simplifies the exposure process. Instead of requiring complex photomask alignment and expensive exposure devices with substrate transmission capability, the photosensitive layer receives the exposure pattern directly through the substrate, enabling accurate pattern transfer using simpler and more cost-effective exposure equipment.
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 enables high-accuracy alignment of current injection regions and lenses, improving the electrical and optical properties of the light-emitting device while reducing production costs and complexity.
Implementation Method 1
applying light having the exposure wavelength to the substrate from the side of the first main surface and forming the photosensitive layer into a pattern corresponding to the light-blocking structure
Data Source
AI summary
To provide a semiconductor light-emitting device that has excellent productivity and is capable of aligning a current injection region and a lens with high accuracy, and a method of producing the semiconductor light-emitting device. A method of producing a light-emitting device according to the present technology includes: forming a light-blocking structure that is a structure opaque to an exposure wavelength on a side of a first main surface of a substrate having the first main surface and a second main surface on a side opposite to the first main surface; forming a photosensitive layer that is formed of a photosensitive material on a side of the second main surface of the substrate; applying light having the exposure wavelength to the substrate from the side of the first main surface and forming the photosensitive layer into a pattern corresponding to the light-blocking structure; and forming a lens using the photosensitive layer.