Wafer Partial Cuts Reduce Warpage During Thinning
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Solution Overview
Problem
Current wafer thinning technologies face challenges such as wafer warpage, breakage, and increased costs due to high adhesion strength grinding tape and the need for specialized equipment like dedicated lasers, which are not effectively addressed by existing methods like Dicing Before Backgrind (DBG).
Innovation Solution
The implementation of a wafer system with partial cuts formed on the topside within the wafer rim, allowing for thinning from the backside without traversing through the entire thickness, which reduces wafer warpage, eliminates the need for special alignment systems and high-cost grinding tape, and avoids the use of dedicated lasers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer diameter is increased to meet large volume production demands, then productivity increases, but wafer warpage and breakage worsen
Solution Approach 1:
The wafer is segmented into multiple regions through partial cuts that divide the wafer into separate zones. This segmentation allows different regions to be handled independently during thinning, reducing the overall warpage stress across the entire wafer structure while maintaining production efficiency.
Solution Approach 2:
The patent applies local quality by performing thinning operations on specific regions of the wafer rather than uniformly across the entire wafer. The partial cuts enable selective thinning in areas where it is most needed, reducing overall warpage while maintaining structural integrity in critical regions.
2Stability of the object's composition
If Dicing Before Backgrind (DBG) is used to reduce wafer stress, then wafer stability improves, but device complexity and manufacturing cost worsen
Solution Approach 1:
Instead of performing complete dicing before backgrind, the patent applies partial cuts that do not fully separate the wafer into individual dice. This partial action is sufficient to reduce wafer stress and improve stability during thinning, while avoiding the complexity and cost of complete dicing and subsequent re-alignment operations.
3Manufacturing precision
If dedicated laser and alignment systems are used for cutting die attach film in DBG, then manufacturing precision improves, but device complexity and cost worsen
Solution Approach 1:
The patent extracts and eliminates the need for dedicated laser systems and special alignment equipment by using partial cuts that can be performed with standard wafer processing equipment. The die attach film cutting function is achieved through the partial cut structure itself, removing the requirement for specialized cutting equipment.
4Reliability
If thick grinding tape with high adhesion strength is used to hold separated dice, then reliability improves, but cost worsens
Solution Approach 1:
The patent uses partial cuts that do not fully separate the wafer into individual dice, eliminating the need for thick high-adhesion grinding tape. The partial cut structure provides sufficient support during thinning without requiring expensive specialized tape materials, thereby reducing manufacturing costs while maintaining reliability.
Data Source
AI summary
A wafer system is provided including providing a wafer having a topside and a backside, forming a partial cut from the topside of the wafer within a wafer rim and thinning the wafer from the backside for exposing the partial cut at the backside within the wafer rim.