Recessed Semiconductor Wafer Structure for Stress-Balanced Etching
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Solution Overview
Problem
Semiconductor wafers without integrated devices face challenges in maintaining uniformity and stability during film formation and etching processes due to differences in surface areas and stress distribution, leading to potential warpage and inefficiencies in film removal.
Innovation Solution
A semiconductor wafer design featuring recesses with exposed inner walls and partitions to increase surface area, allowing for stress dispersion and improved film formation and etching processes, utilizing metal-assisted chemical etching and other methods to create recesses with controlled dimensions and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a semiconductor wafer without integrated devices is used, then film formation and etching processes can be performed, but warpage occurs due to non-uniform stress distribution
Solution Approach 1:
The wafer surface is segmented into multiple regions with different stress characteristics. By creating a first region with tensile stress and a second region with compressive stress, the patent divides the uniform wafer structure into functionally distinct zones that collectively balance overall stress distribution, preventing warpage while maintaining processability.
Solution Approach 2:
Different regions of the wafer are assigned different local stress properties. The first region is engineered to have tensile stress while the second region has compressive stress, creating local quality variations that compensate for each other and achieve global stress balance, thereby maintaining wafer flatness during processing.
2Stability of the object's composition
If the wafer surface area is increased to improve stress distribution, then warpage is reduced, but the wafer becomes more susceptible to deformation
Solution Approach 1:
The patent applies counterbalancing stress principles by creating regions with opposite stress signs (tensile and compressive). These opposing stress fields act as mechanical counterweights that neutralize each other's deforming effects, allowing the wafer to maintain both large surface area for stress distribution and sufficient rigidity through stress equilibrium.
Solution Approach 2:
The wafer structure employs asymmetric stress distribution with distinct tensile and compressive regions rather than uniform stress. This asymmetric design creates a balanced stress system where the asymmetry in local stress states produces symmetry in overall structural stability, preventing both warpage and excessive deformation.
3Manufacturing precision
If metal-assisted chemical etching is used to create recesses, then precise control of recess dimensions is achieved, but additional manufacturing steps are required
Solution Approach 1:
A metal layer is introduced as an intermediary element in the etching process. This metal layer serves as a sacrificial mask and etching catalyst, enabling precise recess formation through metal-assisted chemical etching. The intermediary metal layer facilitates controlled material removal while maintaining dimensional accuracy, justifying the additional process step through superior precision.
Solution Approach 2:
The patent utilizes parameter changes in the etching process, specifically changing the chemical environment and etching mechanism by introducing metal-assisted chemical etching. This parameter change enables precise control of recess dimensions through controlled metal dissolution and selective etching, achieving manufacturing precision that outweighs the increased process complexity.
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 increased surface area and stress dispersion prevent warpage, enhance film removal, and enable repeated use for continuous film formation and etching, improving the uniformity and reliability of semiconductor devices.
Implementation Method 1
utilizing metal-assisted chemical etching and other methods to create recesses with controlled dimensions and orientations
Data Source
AI summary
A semiconductor wafer includes a surface having at least one recess including an inner wall surface. The inner wall surface is exposed.