Optical Element Dicing with Barrier Material for Thermal Reliability
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Solution Overview
Problem
Existing light-shaping optical elements, such as polymer-on-glass diffusers, face challenges in reliability during thermal cycling due to defects at the dicing edges and corners when diced into small sizes, leading to delamination or cohesive failure.
Innovation Solution
A die with a substrate and optical elements separated by a barrier material, where the wafer is diced along a street to minimize damage, and the method involves dispensing an elastomeric material, using a soft mold tool with a photomask, and applying a barrier material to reduce cross-talk and enhance separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If light-shaping optical elements are diced into small sizes (3x2 mm or smaller), then the optical elements can be used in compact applications, but defects form along the dicing edge and in corners leading to delamination or cohesive failure during thermal cycling
Solution Approach 1:
The patent introduces dicing streets that completely separate adjacent optical elements, dividing the wafer into independent sections. This segmentation prevents stress and defects from propagating between elements during dicing and thermal cycling, thereby maintaining reliability even when elements are diced to small sizes.
Solution Approach 2:
The patent applies a barrier material to the dicing streets before dicing the wafer. This preliminary action protects the edges and corners of optical elements from damage during the subsequent dicing process, preventing the formation of defects that would lead to delamination or cohesive failure during thermal cycling.
2Productivity
If multiple optical elements are placed on a wafer for batch processing, then productivity increases, but cross-talk between adjacent optical elements occurs
Solution Approach 1:
The barrier material creates optical and physical separation between adjacent optical elements on the wafer. This segmentation allows batch processing of multiple elements while preventing cross-talk, as each element is isolated in its own dicing street-defined region.
Solution Approach 2:
The barrier material acts as an intermediary substance placed in the dicing streets between optical elements. It provides both mechanical separation during dicing and optical isolation to prevent cross-talk, enabling high-density wafer-level processing without harmful interactions between elements.
3Reliability
If barrier material is applied to dicing streets before dicing, then damage to individual dies during dicing is reduced, but an additional manufacturing step is required
Solution Approach 1:
The patent combines the barrier material application step with the existing wafer processing workflow. The barrier material is applied to dicing streets as part of the standard fabrication process, merging protection functionality with routine manufacturing operations to minimize additional complexity.
Solution Approach 2:
The barrier material is applied in advance to the dicing streets before the dicing process occurs. This preliminary protection step prevents edge and corner damage during dicing, and because it is performed before the critical dicing operation, it integrates smoothly into the existing manufacturing sequence without requiring major process reorganization.
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
The solution effectively reduces damage during dicing, inhibits cross-talk between optical elements, and enhances the reliability of light-shaping optical elements by ensuring a continuous interface between the substrate and optical elements, improving thermal cycling performance.
Implementation Method 1
dispensing an elastomeric material onto a substrate; contacting the elastomeric material with a soft mold tool including a photomask; and curing portions of the elastomeric material
Data Source
AI summary
A die including a substrate; and a plurality of optical elements on a portion of a surface of the substrate; in which each optical element, of the plurality of optical elements, includes at least one optical function; and in which each optical element, of the plurality of optical elements, is separated one from another by a barrier material is disclosed. A wafer including a plurality of dies; a method of making a wafer; and a method of making a die are also disclosed.