Patterned Sacrificial Layer for Precise Cavity Etching
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Solution Overview
Problem
Existing methods for creating cavity structures in semiconductor devices often result in longer processing times and excessive undercut due to limited release hole locations, which affect the shape and precision of anchor structures during etching.
Innovation Solution
A patterned sacrificial layer is used, with pre-defined channels and strategically placed release holes to control etching distance and shape, allowing for precise formation of cavities and anchor structures without excessive undercut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If release holes are used for etching around the anchor structure, then the cavity structure can be formed, but the processing time increases and excessive undercut occurs
Solution Approach 1:
The sacrificial layer is patterned before the etching process to pre-define the cavity shape and etching paths. This preliminary patterning establishes precise etching boundaries and controlled access points, eliminating the need for extended etching times and preventing excessive undercut of the anchor structure.
Solution Approach 2:
The sacrificial layer is divided into patterned regions with different etch selectivity, creating distinct etching zones. This segmentation allows selective removal of sacrificial material in specific areas while preserving other regions, enabling precise cavity formation with controlled dimensions and minimal undercut.
2Manufacturing precision
If release holes are limited to certain locations, then the etching process can be controlled, but the anchor structure shape is affected and precision is reduced
Solution Approach 1:
The patterned sacrificial layer serves as an intermediary structure that mediates between the release holes and the anchor structure. It provides a controllable etching pathway that is independent of release hole locations, allowing precise anchor structure formation regardless of where release holes are positioned in the device layout.
3Productivity
If etching is performed from limited release hole locations, then the process can be simplified, but excessive undercut occurs and processing time increases
Solution Approach 1:
The sacrificial layer is patterned before etching to pre-define the cavity shape and etching paths. This preliminary patterning establishes precise etching boundaries and controlled access points, eliminating the need for extended etching times and preventing excessive undercut of the anchor structure.
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 enables more precise control over etching distance and shape, reducing processing time and minimizing undercut, while maintaining structural integrity and uniformity across the wafer.
Implementation Method 1
The sacrificial layer is etched through the at least one release hole
Data Source
AI summary
A method includes forming a sacrificial layer over a bottom substrate. The sacrificial layer is patterned based on a desired etching distance. A top layer is formed over the sacrificial layer. At least one release hole is formed through the top layer. The sacrificial layer is etched through the at least one release hole.