Singulation Street Light Trap Layer for WLCSP Dielectric Patterning
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Solution Overview
Problem
In Wafer Level Chip Scale Packages (WLCSP), the existing methods face challenges in accurately removing the second buildup dielectric layer above singulation streets to prevent partial or complete polymerization, which affects the precise formation of singulation street trenches and redistribution pattern terminals, leading to potential defects in the electronic component packages.
Innovation Solution
A singulation street exposure light trap layer is formed using a dielectric material that traps and diffuses exposure light, preventing it from reflecting and polymerizing the second buildup dielectric layer above singulation streets, ensuring complete removal and precise formation of singulation street trenches and redistribution pattern terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exposure light is used to pattern the second buildup dielectric layer, then the dielectric layer can be removed to form singulation street trenches, but the exposure light reflects off the singulation streets and causes partial or complete polymerization of the dielectric layer above the singulation streets, preventing complete removal
Solution Approach 1:
A singulation street exposure light trap layer is introduced as an intermediary between the singulation streets and the second buildup dielectric layer. This light trap layer absorbs and diffuses the reflected exposure light, preventing it from reaching and polymerizing the dielectric layer above the singulation streets, thereby enabling complete and precise removal of the dielectric layer to form accurate singulation street trenches
Solution Approach 2:
The reflected exposure light, which originally causes harmful polymerization, is converted into a beneficial effect by using it to form the light trap layer itself. The light trap layer is created in the singulation street regions, and when exposure light reflects off this layer, it is absorbed and diffused, preventing polymerization of the dielectric layer while enabling precise trench formation
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 approach ensures the accurate and complete removal of the second buildup dielectric layer above singulation streets, enhancing the precision of singulation street trenches and redistribution pattern terminals, thereby improving the quality and reliability of electronic component packages.
Implementation Method 1
A singulation street exposure light trap layer 326 is formed on singulation streets 206. Singulation street exposure light trap layer 326 traps and diffuses the exposure light thus preventing the exposure light from being reflected to the portion of second buildup dielectric layer 750 above singulation streets 206.
Data Source
AI summary
A method includes forming a first buildup dielectric layer on a wafer. The wafer includes electronic components delineated from one another by singulation streets. A singulation street exposure light trap layer is formed on the singulation streets. A second buildup dielectric layer is applied and patterned by being selectively exposed to an exposure light. The singulation street exposure light trap layer traps and diffuses the exposure light thus preventing the exposure light from being reflected to the portion of the second buildup dielectric layer above the singulation streets. In this manner, complete removal of the second buildup dielectric layer above the singulation streets is insured.