Selective Ambient Light Shielding at Semiconductor Chip Level
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electromagnetic shielding methods encapsulate semiconductor devices entirely, which is inadequate for devices with photonic components that require selective exposure to ambient light, as they fail to allow necessary light exposure while preventing electromagnetic interference.
Innovation Solution
Integration of a light shielding layer with passivation layers to isolate ambient light from photo-sensitive circuits, using a conductive material for efficient shielding and electrical isolation, and a deep trench to prevent light entry from the sides, allowing selective exposure through self-aligned device structures with minimal processing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PCB-level shielding encapsulates the entire semiconductor device, then electromagnetic interference is blocked, but photonic components cannot receive necessary ambient light
Solution Approach 1:
The shielding structure is segmented into region-specific zones: complete shielding over circuit regions and selective transparency over photonic component regions. This allows different parts of the device to have different shielding requirements, enabling both EMI protection for circuits and light access for photonic components without requiring full encapsulation.
Solution Approach 2:
The passivation layer structure implements local quality by varying its composition and thickness across different device regions. Circuit areas receive full shielding with conductive materials, while photonic areas maintain light transmission properties. This localized differentiation resolves the contradiction between uniform shielding and selective light exposure.
2Adaptability or versatility
If a light shielding layer is integrated at chip level, then selective light exposure is achieved, but processing complexity increases
Solution Approach 1:
The light shielding layer is merged with the existing passivation layer structure rather than being implemented as a separate component. By integrating the shielding function into the passivation layers that are already part of the semiconductor fabrication process, the solution achieves selective light exposure without adding significant processing complexity or requiring separate shielding components.
Solution Approach 2:
The passivation layers serve multiple functions simultaneously: they provide electrical isolation, mechanical protection, and region-specific electromagnetic shielding. This multi-functionality eliminates the need for separate dedicated shielding structures, reducing overall device complexity while achieving selective light exposure capabilities.
3Object-affected harmful factors
If conductive material is used for light shielding, then shielding efficiency is improved, but electrical isolation requirements increase
Solution Approach 1:
The electrical isolation function is merged with the light shielding function in the same passivation layer structure. The conductive shielding material is deposited within the passivation layer framework, which inherently provides electrical isolation through its insulating properties and structural design. This integration eliminates the need for separate isolation structures while maintaining both shielding efficiency and electrical safety.
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
Effectively shields ambient light from photo-sensitive circuits while allowing necessary light exposure to photonic components, enhancing the performance of semiconductor devices with reduced processing costs and avoiding the need for external casings.
Implementation Method 1
a light shielding layer that block ambient light from reaching such circuits
Implementation Method 2
The light shielding layer is preferably a conductive material, as it is more efficient in shielding ambient light than non-conductive material
Data Source
AI summary
A semiconductor device having a substrate with at least one photo-detecting region and at least one bond pad is provided. A first passivation layer is deposited over the substrate and over step portions at the edges of the bond pad and a trench having sidewalls and a bottom surface is formed in the substrate. A light shielding layer is deposited over the first passivation layer and covering the trench sidewalls. The light shielding layer has end portions at the photo-detecting region, at step portions at the edges of the bond pad and at the bottom surface of the trench. A second passivation layer is deposited over the light shielding layer. A third passivation layer is deposited over the end portions of the light shielding layer at the photo-detecting region and at the step portions at edges of the bond pad.