Optical Sensor Trench Light Blocking
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Solution Overview
Problem
Existing methods for manufacturing optical sensors are inefficient and costly, particularly when it comes to blocking light entry from specific directions, as they often require complex processes like thick coatings or wafer-level packaging that increase size and weight, or are not feasible due to back grinding limitations.
Innovation Solution
A method involving a carrier with optical sensor elements and a light entrance surface, where trenches are formed between elements and filled with opaque material to block unwanted light, allowing for efficient production and surface-mountability, while maintaining a thin opaque coating that does not significantly increase the sensor's footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If thick coating layers are applied as side walls on a single die level to block light, then light blocking is achieved, but the production process becomes complicated and the size and weight of the optical sensor device increase
Solution Approach 1:
The patent transitions from single-die-level coating to wafer-level processing, adding a dimensional aspect to the manufacturing approach. Multiple optical sensor elements are processed simultaneously on a wafer, with trenches formed and coated at the wafer level before singulation, thereby simplifying the production process while achieving effective light blocking.
Solution Approach 2:
The patent combines multiple functions into the wafer-level processing step: trench formation, opaque coating application, and light blocking are all achieved in the same manufacturing stage. This merging of operations eliminates the need for separate thick coating steps on individual dies, reducing production complexity.
2Ease of manufacture
If wafer-level packaging is used to coat optical sensors, then the production is cheaper and smaller, but the process becomes inefficient and complicated requiring back grinding
Solution Approach 1:
The patent performs preliminary actions by forming trenches and applying opaque coatings at the wafer level before the sensors are singulated and packaged. This preliminary processing eliminates the need for back grinding and subsequent individual die coating, thereby improving manufacturing efficiency while maintaining the cost and size advantages of wafer-level production.
3Object-affected harmful factors
If wafer-level processes are used to block light from bottom side, then light blocking is achieved, but the process requires back grinding which is not feasible in every case
Solution Approach 1:
Instead of blocking light from the bottom side through back grinding, the patent inverts the approach by forming trenches and applying opaque coatings on the front side of the wafer at the wafer level. This inverted methodology achieves the same light blocking function without requiring back grinding, thereby improving process feasibility and adaptability to different sensor designs.
4Object-affected harmful factors
If opaque coating is applied to cover side surfaces, then light blocking is achieved, but the footprint of the optical sensor increases significantly
Solution Approach 1:
The patent applies local quality by forming trenches only in specific locations where light blocking is needed, rather than coating the entire side surface. The opaque material is deposited selectively within the trench structures, providing localized light blocking functionality while preserving the original sensor footprint and not increasing the overall device area.
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 cost-effective and efficient production of optical sensors with controlled light entry, reducing material usage and processing complexity, allowing for simultaneous manufacturing of thousands of sensors on a wafer level, and ensuring the sensors are surface-mountable with minimal footprint increase.
Implementation Method 1
forming a trench between two optical sensor elements... coating the trench with an opaque material... ensuring that the light entrance surface is free of the opaque material above the optical sensor elements
Data Source
AI summary
A method for manufacturing an optical sensor is provided. The method comprises providing an optical sensor arrangement which comprises at least two optical sensor elements on a carrier, where the optical sensor arrangement comprises a light entrance surface at the side of the optical sensor elements facing away from the carrier. The method further comprises forming a trench between two optical sensor elements in a vertical direction which is perpendicular to the main plane of extension of the carrier, where the trench extends from the light entrance surface of the sensor arrangement at least to the carrier. Moreover, the method comprises coating the trench with an opaque material, forming electrical contacts for the at least two optical sensor elements on a back side of the carrier facing away from the optical sensor elements, and forming at least one optical sensor by dicing the optical sensor arrangement along the trench. Each optical sensor comprises an optical sensor element, and the light entrance surface is free of electrical contacts and at least partially free of the opaque material above the optical sensor elements. Furthermore, an optical sensor is provided.