Plasma Etching Wafer Strain Removal
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Solution Overview
Problem
Conventional plasma etching methods struggle to effectively remove processing strains, debris, and modified layers from deep positions within wafers without causing excessive etching on the surface, particularly in grooves formed during wafer processing.
Innovation Solution
A method involving the application of a protective film, forming grooves or cut grooves, and using an etching gas in a plasma state delivered through a supply nozzle into a vacuum chamber, where radicals are more prevalent than ions, allowing for targeted removal of processing strains and debris from deep positions without excessive surface etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a grinding process is used to thin the wafer, then the size and weight of device chips are reduced, but processing strains are generated on the ground surface
Solution Approach 1:
The patent converts the harmful processing strains generated by grinding into a beneficial treatment process. By applying plasma etching to the ground surface, the same plasma that could potentially cause damage is instead used to remove the strained material layer, transforming the harmful effect into a useful strain removal mechanism that improves wafer quality.
2Object-generated harmful factors
If plasma etching is applied to remove processing strains, then strains are removed from the wafer, but it is difficult to reach deep positions in grooves without excessive surface etching
Solution Approach 1:
The patent applies local quality by creating non-uniform plasma distribution that is concentrated in specific regions. The plasma generation is localized to areas where it is most needed (at the wafer surface and penetrating into grooves) rather than being uniformly distributed. This allows effective strain removal from deep positions while minimizing excessive etching on the exposed surface, achieving both goals simultaneously.
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 effective removal of processing strains and debris from deep within wafers without excessive etching on the surface, improving the precision and efficiency of wafer processing.
Implementation Method 1
turning an etching gas into a plasma state outside of a vacuum chamber which houses the wafer therein, and delivering the etching gas in the plasma state into the vacuum chamber through a supply nozzle connected to the vacuum chamber
Implementation Method 2
applying a laser beam having a wavelength that is absorbable by the wafer to the wafer to form processed grooves in the wafer
Data Source
AI summary
A method of processing a wafer includes a plasma etching step of supplying an etching gas in a plasma state to the wafer to remove processing strains, debris, or modified layers. The plasma etching step includes turning an etching gas into a plasma state outside of a vacuum chamber which houses the wafer therein and delivering the etching gas in the plasma state into the vacuum chamber through a supply nozzle connected to the vacuum chamber.