Inclined Sidewall Semiconductor Packages for Optical Coupling
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Solution Overview
Problem
In semiconductor device packages, the distance between a light emitter and an optical sensor results in lower optical transmission efficiency and accuracy due to uneven sidewalls during the manufacturing process of optical devices, which complicates the integration with optical fibers or laser diodes and increases costs when polishing and applying anti-reflection films.
Innovation Solution
The semiconductor device package features a substrate with a passivation layer and an optical element, where the sidewall of the substrate is inclined at an angle of approximately 87 to 89 degrees, and the distance between the sidewalls of adjacent optical devices is less than 2 micrometers, achieved through a manufacturing process involving Deep Reactive Ion Etching and backside grinding to reduce roughness and distance, thereby improving light transmission quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the distance between light emitter and optical sensor is reduced, then optical transmission efficiency is improved, but manufacturing precision requirements increase due to tighter coupling tolerances
Solution Approach 1:
The substrate sidewall is pre-formed with an inclined angle of 87-89 degrees during the manufacturing process, positioning the optical element's sidewall in advance to achieve the desired small lateral distance. This preliminary geometric configuration enables tight coupling between optical components while maintaining manufacturing feasibility through standard semiconductor fabrication techniques.
2Ease of manufacture
If blade saw cutting is used to singulate wafers, then manufacturing cost is reduced, but sidewall uniformity deteriorates affecting light transmission quality
Solution Approach 1:
The patent replaces the mechanical blade saw cutting process with Deep Reactive Ion Etching (DRIE), a plasma-based chemical etching process. This substitution eliminates the mechanical contact that causes uneven sidewalls, producing vertically uniform sidewalls with high precision while remaining compatible with semiconductor manufacturing workflows.
Solution Approach 2:
The invention changes the manufacturing parameter from mechanical cutting to controlled chemical etching with specific process parameters (plasma chemistry, temperature, pressure). This parameter change transforms the sidewall formation mechanism, achieving uniform sidewalls through controlled chemical reactions rather than mechanical force.
3Manufacturing precision
If polishing and anti-reflection coating are applied to sidewalls, then light transmission quality is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The invention converts the potential harm of exposed sidewalls into a benefit by designing the optical element geometry such that the sidewall itself becomes the functional light transmission interface. The inclined sidewall configuration naturally guides light without requiring additional polishing or coating processes, turning what would be a problematic surface into a useful optical component.
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 configuration enhances light transmission efficiency and accuracy by reducing the distance between optical components, simplifying the manufacturing process, and maintaining low surface roughness, thus improving the integration of optical devices with optical fibers or laser diodes without the need for costly polishing and anti-reflection coatings.
Implementation Method 1
achieved through a manufacturing process involving Deep Reactive Ion Etching
Implementation Method 2
backside grinding to reduce roughness
Data Source
AI summary
A semiconductor device includes a substrate, a passivation layer and an optical element. The substrate includes a surface and a sidewall. The passivation layer is disposed on the surface of the substrate. The optical element is disposed in the substrate and exposed from the sidewall of the substrate. The sidewall of the substrate is inclined towards the surface of the substrate at an angle of approximately 87 degrees to approximately 89 degrees.