Semiconductor Substrate Backside Texturing for Lithographic Distortion
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Solution Overview
Problem
In integrated circuit manufacturing, the backside of semiconductor substrates often becomes contaminated and uneven, leading to significant distortion during chucking on imaging scanners, which affects the alignment of lithographic layers and overall performance.
Innovation Solution
The backside of semiconductor substrates is texturized to create a uniform coefficient of friction, reducing distortion by employing chemical etching, plasma processing, or mechanical polishing to improve slippage uniformity across chuck pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the backside of semiconductor substrates is left smooth and clean, then handling and processing is easier, but significant distortion occurs during chucking due to non-uniform slippage
Solution Approach 1:
The backside surface morphology is changed from smooth to texturized by modifying the physical state and structure of the surface. This texturization creates a more uniform coefficient of friction across the backside surface, which reduces non-uniform slippage during chucking and improves wafer distortion uniformity.
Solution Approach 2:
The backside texturization is performed as a preliminary process step before lithography and other critical manufacturing steps. By preparing the backside surface in advance, the patent prevents distortion issues from affecting subsequent processing steps, ensuring better overlay performance without interfering with ease of manufacture.
2Manufacturing precision
If chemical etching or plasma processing is used to texturize the backside, then slippage uniformity improves, but process complexity and time increase
Solution Approach 1:
The patent replaces mechanical polishing methods with chemical etching or plasma processing to create backside texturization. These alternative methods can achieve the desired surface morphology more efficiently and with better uniformity control, reducing the overall process time while maintaining or improving slippage uniformity.
3Manufacturing precision
If mechanical polishing is used to texturize the backside, then distortion uniformity improves, but surface contamination and scratches increase
Solution Approach 1:
The patent replaces mechanical polishing with chemical etching or plasma processing methods. These non-mechanical approaches create the necessary surface texturization without introducing mechanical scratches, particle contamination, or surface damage that would result from mechanical contact during polishing.
Solution Approach 2:
Plasma processing is performed in a controlled inert or reactive plasma environment that prevents contamination from external sources. The plasma process itself cleans the surface while simultaneously texturizing it, ensuring that no extraneous particles or contaminants are introduced during the texturization process.
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 results in more uniform wafer distortion signatures and enhanced overlay performance during lithography, improving the alignment of multiple lithographic layers.
Implementation Method 1
employing chemical etching, plasma processing, or mechanical polishing to improve slippage uniformity
Implementation Method 2
employing chemical etching, plasma processing, or mechanical polishing to improve slippage uniformity
Implementation Method 3
employing chemical etching, plasma processing, or mechanical polishing to improve slippage uniformity
Data Source
AI summary
Embodiments described relate to a method and apparatus for reducing lithographic distortion. A backside of a semiconductor substrate may be texturized. Then a lithographic process may be performed on the semiconductor substrate having the texturized backside.