Wafer Holding Table with Segmented Pins for Resin Bubble Prevention
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Solution Overview
Problem
Conventional protective member forming apparatuses face issues with air bubbles entering the protective member during the curing process, leading to non-uniform thickness of wafers when ground, due to residue from the holding surface causing a gap between the wafer and the resin.
Innovation Solution
A protective member forming apparatus with a holding table featuring upright pins and an annular wall, which minimizes residue accumulation by sucking and holding the wafer securely, and using an adhesive tape with a non-adhesive tape base to prevent air bubbles from entering between the wafer and the resin, ensuring uniform thickness during grinding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a flat holding surface is used to prevent wafer breaking under strong pressing force, then wafer strength is improved, but resin separation and air bubble entry occur due to residue accumulation
Solution Approach 1:
The holding surface is segmented into multiple pin members instead of a continuous flat surface. This segmentation prevents resin from spreading across the entire surface and accumulating, while still providing sufficient holding points to prevent wafer breaking during the pressing process.
Solution Approach 2:
The holding surface uses pin members with spaces between them, creating a porous-like structure that allows resin to be contained in specific areas rather than spreading uniformly across a flat surface. This prevents residue accumulation that causes air bubble formation.
2Productivity
If strong pressing force is applied to spread resin quickly, then productivity is improved, but wafer breaking occurs due to reaction force on flat holding surface
Solution Approach 1:
The segmented pin structure distributes the pressing force through multiple contact points, reducing the reaction force concentration that causes wafer breaking while still enabling effective resin spreading across the wafer surface.
3Ease of manufacture
If a flat holding surface is used, then ease of manufacture is improved, but air bubbles enter protective member due to gap formation from residue
Solution Approach 1:
The pin member structure, while slightly more complex than a flat surface, provides a systematic solution that prevents resin accumulation and air bubble formation, achieving better manufacturing precision with reasonable manufacturing complexity.
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 apparatus effectively suppresses air bubble entry into the protective member, allowing for uniform thickness in wafers during grinding processing by securely holding the wafer and spreading the resin without gaps, thus ensuring consistent grinding results.
Implementation Method 1
a suction path that penetrates the base and communicates with a suction source inside the annular wall
Implementation Method 2
the other surface of the as-sliced wafer held by the holding surface is pressed against the liquid resin. Thereby, the liquid resin is pushed to spread across the whole of the other surface of the as-sliced wafer
Implementation Method 3
The liquid resin pushed to spread is cured by curing means. Thereby, the protective member is formed
Data Source
AI summary
A holding table for holding a wafer includes plural pins, and a wafer holding surface includes the tips of the plural pins. Therefore, small dust enters between the pins and thus is less readily left between the wafer holding surface and the wafer. Therefore, when the wafer is sucked and held, a gap is less readily made between the wafer holding surface and the wafer. Thus, the occurrence of the situation in which the wafer is held in a waving state is suppressed. For this reason, when a liquid resin is pushed to spread over the lower surface of the wafer, an air bubble enters less readily between the liquid resin and the wafer. This can suppress entry of the air bubble in a protective member obtained by curing the liquid resin.