Wafer Edge Trimming via Dry Etching to Prevent Delamination
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Solution Overview
Problem
The bevel edges formed during semiconductor device fabrication processes can lead to non-uniform stress and potential cracking or delamination of wafers, necessitating an effective method for edge trimming to enhance process reproducibility and stability.
Innovation Solution
A method involving the direct bonding of substrates and subsequent dry etching to trim the edge regions, eliminating mechanical stress and thermal stress associated with traditional mechanical trimming, thereby improving process reproducibility and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If mechanical edge trimming is used to remove bevel edges, then the edge quality is improved, but mechanical stress and thermal stress are introduced causing crack and delamination
Solution Approach 1:
The patent replaces the mechanical trimming system with a chemical etching system. Instead of using mechanical tools to physically remove material from the wafer edge, the invention uses chemical etchants to selectively remove the bevel edge region through chemical reactions, thereby eliminating the introduction of mechanical stress and thermal stress that cause cracking and delamination.
Solution Approach 2:
The patent changes the physical-chemical parameters of the trimming process by transitioning from mechanical removal to chemical etching. The etching process uses controlled chemical reactions with specific etchants to remove material, changing the fundamental mechanism from mechanical force to chemical dissolution, which eliminates stress introduction while maintaining edge quality.
2Ease of manufacture
If mechanical trimming tools are used, then edge trimming can be performed, but contamination risk increases and process reproducibility decreases
Solution Approach 1:
The patent replaces mechanical trimming tools with a chemical etching process. This substitution eliminates the variability associated with mechanical tool wear, positioning accuracy, and operator skill, thereby improving process reproducibility. The chemical etching process can be more precisely controlled through parameters such as etchant concentration, temperature, and exposure time.
Solution Approach 2:
The patent employs an inert or controlled chemical environment during the etching process to prevent contamination. By using controlled chemical reactions in a regulated atmosphere, the process minimizes the introduction of foreign particles and contaminants that would otherwise be introduced by mechanical tools, thereby maintaining higher cleanliness and process consistency.
3Device complexity
If bevel edges are retained from wafer thinning, then the fabrication process is simplified, but non-uniform stress is introduced to the wafer edge
Solution Approach 1:
The patent extracts or removes the problematic bevel edge region from the wafer through chemical etching. By selectively removing only the bevel edge portion while leaving the main wafer structure intact, the invention eliminates the source of non-uniform stress without requiring complete redesign of the fabrication process, thus maintaining relative simplicity while solving the stress problem.
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 enhances process reproducibility, reduces the risk of delamination and chipping, and lowers costs by eliminating the need for mechanical tools, while maintaining high cleanliness and preventing contamination.
Implementation Method 1
removing an edge region of the first substrate using a dry etching process
Data Source
AI summary
There is provided a method for fabricating a substrate structure capable of enhancing process reproducibility and process stability by trimming a bevel region of a substrate using a wafer level process. The method includes providing a first substrate including first and second surfaces opposite each other and a first device region formed at the first surface, providing a second substrate including third and fourth surfaces opposite each other and a second device region at the third surface, bonding the first substrate and the second substrate to electrically connect the first device region and the second device region, and forming a trimmed substrate. The forming the trimmed substrate includes etching an edge region of the second substrate bonded to the first substrate.