Ultra Thin Wafer Backside Processing Using Tape Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for ultra thin wafer backside processing face challenges such as low throughput and high risk of wafer breakage during carrier removal and edge ring processing, particularly for wafers thinner than 4 mils, which also result in reduced active area and increased costs.
Innovation Solution
A method and apparatus utilizing a high temperature grinding and dicing tape supported by a ring, allowing for wafer mounting, backside grinding, and subsequent processing steps like ion implantation, annealing, and metallization, while minimizing direct handling and enabling high throughput with low wafer breakage risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temporary support substrate or carrier is adhered to the front side of a device wafer to facilitate wafer back grinding and handling, then wafer warping is reduced and breakage is prevented, but removal of the carrier involves complex operations leading to low throughput and high risk of wafer breakage
Solution Approach 1:
The patent removes the temporary carrier substrate entirely from the process. Instead of adhering a carrier to the wafer front side, the invention uses a rigid edge ring formed directly on the wafer periphery through etching or mechanical back grinding, eliminating the need for carrier adhesion and subsequent complex removal operations, thereby improving throughput while maintaining wafer support and preventing breakage during handling and processing
Solution Approach 2:
The patent segments the wafer structure by creating a rigid edge ring that separates the peripheral support function from the active device area. This edge ring acts as an independent structural element that provides mechanical support and handling capability without requiring a separate carrier substrate, thus simplifying the overall process and improving throughput
2Reliability
If a rigid edge ring is formed on the periphery of a thin wafer to facilitate handling and processing, then wafer support is improved, but throughput during wafer thinning and edge ring removal is low and active area is reduced
Solution Approach 1:
The patent inverts the conventional approach by forming the rigid edge ring through etching or mechanical back grinding of the wafer itself rather than adhering a separate ring. This inversion allows the edge ring to be integrated with the wafer structure, eliminating the need for separate attachment and removal steps, thereby improving throughput during wafer thinning while maintaining handling stability
Solution Approach 2:
The patent merges the edge ring formation with the wafer back grinding process. By combining these operations into a single integrated process step, the patent eliminates separate handling steps and improves throughput during wafer thinning, while the resulting rigid edge ring continues to provide the necessary structural support and handling capability
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 achieves high wafer throughput with low breakage risk and high wafer area usage, enabling processing of wafers down to 2 mils thickness at a low cost, with improved processing efficiency and reduced machine and consumables costs.
Implementation Method 1
mounting a ring and a wafer to a high temperature grinding and dicing tape with a wafer front side adhered to the tape
Implementation Method 2
grinding a wafer back side
Implementation Method 3
back side processing such as ion implantation
Implementation Method 4
annealing
Data Source
AI summary
A method and apparatus for ultra thin wafer backside processing are disclosed. The apparatus includes an outer ring holding a high temperature grinding and/or dicing tape to form a support structure. An ultra thin wafer or diced wafer is adhered to the tape within the ring for wafer backside processing. The wafer backside processing includes ion implantation, annealing, etching, sputtering and evaporation while the wafer is in the support structure. Alternative uses of the support structure are also disclosed including the fabrication of dies having metalized side walls.