Wafer Edge Plasma Etching for Precise Wafer-to-Wafer Bonding
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Solution Overview
Problem
Conventional wafer edge trimming processes using mechanical trimming methods result in wider trimmed portions and often lead to wafer chipping, which can compromise the integrity and precision of wafer bonding in integrated circuit packaging.
Innovation Solution
The process involves using an etching method, specifically plasma etching, to trim the edges of wafers, forming a recessed top surface with a planar inner portion and a raised outer portion, which reduces the trimmed width and avoids mechanical chipping by eliminating the need for physical force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical trimming methods are used to trim wafer edges, then the trimming process is simple and fast, but the trimmed portions become wider and wafer chipping occurs
Solution Approach 1:
The patent replaces mechanical trimming methods with plasma etching technology. Instead of using mechanical force to remove material, the invention uses plasma chemistry to selectively etch the wafer edges, thereby avoiding mechanical chipping and achieving narrower, more precise trimmed portions while maintaining high productivity
2Ease of manufacture
If mechanical trimming methods are used to trim wafer edges, then the process is straightforward, but wafer chipping occurs compromising integrity
Solution Approach 1:
The invention substitutes mechanical trimming with plasma etching, replacing physical contact and force with a chemical vapor deposition-based etching process. This eliminates the mechanical stress that causes chipping and maintains wafer integrity, while the process remains manufacturable through standardized plasma processing equipment
Solution Approach 2:
The patent changes the fundamental parameter of the trimming process from mechanical force to plasma chemical reactions. By controlling plasma parameters such as power, gas flow, and pressure, the process achieves precise edge trimming without the harmful mechanical effects, thereby improving reliability while maintaining ease of manufacture
3Length of stationary object
If mechanical trimming is performed, then the trimmed width is larger, but the surface profile becomes uneven with chipping
Solution Approach 1:
The patent replaces mechanical trimming with plasma etching, which removes material through chemical reactions rather than mechanical abrasion. This produces a smooth, uniform surface profile without chipping or unevenness, while achieving the desired narrower trimmed width appropriate for hybrid and fusion bonding applications
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 allows for narrower trimmed edges and prevents wafer chipping, enhancing the precision and reliability of wafer bonding while maintaining a smooth surface profile, suitable for hybrid and fusion bonding in integrated circuit packaging.
Implementation Method 1
performing a wafer edge trimming process to trim an edge portion of the first wafer... The wafer edge trimming process is performed through an etching process, which may be a plasma etching process
Data Source
AI summary
A method includes forming an etching mask over a first wafer. The etching mask covers an inner portion of the first wafer. A wafer edge trimming process is performed to trim an edge portion of the first wafer, with the etching mask protecting the inner portion of the first wafer from being etched. The edge portion forms a full ring encircling the inner portion of the first wafer. The method further includes removing the etching mask, and bonding the first wafer to a second wafer.