Optical Sensor Metal-Via Layout for Crosstalk Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical crosstalk between light-sensitive parts of semiconductor-based sensor devices due to stray light and electromagnetic radiation, which conventional light protection measures fail to adequately block, affects the functionality of active circuitry.
Innovation Solution
The optical sensor device features a stack of metal layers with a via structure arranged such that no direct path is provided between active circuitry and light-sensitive structures, with the via structure interconnecting the metal layers and semiconductor body in a manner that blocks electromagnetic radiation, preventing it from reaching the active circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional light protection measures are used, then the device structure remains simple, but optical crosstalk between light-sensitive parts and active circuitry cannot be adequately blocked
Solution Approach 1:
The device is segmented into distinct functional regions: a light-sensitive area with aperture openings for light entry, and active circuitry areas separated by via structures. This segmentation prevents stray light from reaching the active circuitry while maintaining electrical connectivity where needed, thereby reducing optical crosstalk without requiring complex additional shielding components.
Solution Approach 2:
The metal layers are configured with locally optimized properties: they form apertures specifically over the light-sensitive area to allow light entry, while in other regions they provide electromagnetic shielding. The via structures are strategically placed to provide local electrical connections while blocking light paths. This local differentiation of metal layer functionality achieves effective light blocking with minimal structural complexity.
2Reliability
If metal layers are added to block electromagnetic radiation, then optical crosstalk is reduced, but the device complexity increases
Solution Approach 1:
The metal layers serve multiple functions simultaneously: they provide electromagnetic shielding to block stray light from reaching active circuitry, they form apertures to define the field of view for the light-sensitive area, and they serve as interconnection layers for electrical contacts. This multi-functionality reduces the need for additional dedicated shielding structures, thereby maintaining reliability while limiting the increase in device complexity.
3Illumination intensity
If apertures are created in metal layers for light entry, then light-sensitive area functionality is enabled, but electromagnetic radiation may reach active circuitry
Solution Approach 1:
The metal layers are segmented to create apertures specifically positioned over the light-sensitive area, allowing light to enter while the surrounding metal regions continue to provide electromagnetic shielding. The via structures are segmented and positioned to block light paths while allowing electrical connectivity in specific locations, thus enabling light entry without compromising electromagnetic protection of the active circuitry.
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 effectively reduces optical crosstalk by blocking stray light and electromagnetic radiation, ensuring the integrity of active circuitry and improving the performance of optical sensor devices.
Implementation Method 1
The via structure is arranged in such a fashion that any straight line that is parallel to the light-sensitive area and traverses the aperture opening between the light-sensitive area and the upper metal layer is limited in both of its opposite directions by the via structure
Implementation Method 2
the light-sensitive structure is configured to convert electromagnetic radiation incident on the structure into an electric current based on the photoelectric effect
Data Source
AI summary
An optical sensor device comprises a semiconductor body with a light-sensitive area, metal layers which are arranged above the light-sensitive area and comprise an upper metal layer and a lower metal layer, wherein the upper metal layer is located at a greater distance from the light-sensitive area than the lower metal layer. The optical sensor device further comprises an aperture opening in the metal layers above the light-sensitive area and a via structure, which is arranged outside the aperture opening and interconnects the metal layers and/or the semiconductor body. The via structure is arranged in such a fashion that any straight line that is parallel to the light-sensitive area and traverses the aperture opening between the light-sensitive area and the upper metal layer is limited in both of its opposite directions by the via structure.