Laser Array Heating for Plasma Etch CD Uniformity
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Solution Overview
Problem
The challenge in semiconductor manufacturing is achieving uniformity in plasma etching processes across semiconductor substrates due to spatial variations in plasma density, process chemistry, and substrate temperature, which affects critical dimension uniformity, especially as feature sizes decrease.
Innovation Solution
A laser-based system is employed to control substrate temperature locally and precisely by using laser emitters and lenses to heat discrete portions of the substrate, combined with a controller for feedback and adjustment, allowing independent temperature control of different areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used, then manufacturing process is simple, but critical dimension uniformity deteriorates due to spatial variations in plasma density, process chemistry, and substrate temperature
Solution Approach 1:
The substrate surface is divided into multiple discrete regions, each independently heated by separate laser emitters. This segmentation allows different temperature profiles to be applied to different areas of the substrate, compensating for spatial variations in plasma density and chemistry, thereby improving critical dimension uniformity across the entire substrate.
Solution Approach 2:
Each region of the substrate receives customized heating from dedicated laser emitters, creating locally optimized temperature conditions. This local quality control enables precise compensation for spatial variations in process parameters, achieving uniform etching results across regions that would otherwise exhibit significant variation.
2Adaptability or versatility
If uniform substrate temperature is maintained, then process uniformity improves, but ability to compensate for spatial variations deteriorates
Solution Approach 1:
The system dynamically adjusts the temperature of each substrate region in real-time based on spatial variations in plasma density and chemistry. Laser emitters are controlled to provide varying temperature levels across different areas, enabling the system to adapt to local process conditions while maintaining overall process uniformity through coordinated control.
Solution Approach 2:
The temperature parameter is varied across different spatial regions of the substrate rather than maintaining a single uniform value. By changing the temperature parameter locally to match spatial variations in plasma conditions, the system achieves both adaptability to local variations and overall process uniformity.
3Manufacturing precision
If feature size is decreased, then device density improves, but critical dimension uniformity deteriorates due to increased sensitivity to process variations
Solution Approach 1:
For small features, the system applies locally optimized heating to each region where etching occurs. This local quality control ensures that each small feature experiences optimal temperature conditions specific to its location, compensating for the increased sensitivity to process variations that accompanies smaller feature sizes.
Solution Approach 2:
The system replaces conventional uniform thermal control with optically-based localized heating using laser emitters. This substitution enables precise spatial control of temperature without the mechanical constraints of conventional heating methods, allowing optimal temperature profiles for small features while maintaining overall process stability.
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 uniformity and critical dimension uniformity by precisely controlling substrate temperature, improving the precision and density of etched features such as trenches, vias, and finFET devices.
Implementation Method 1
A laser-based system is employed to control substrate temperature locally and precisely by using laser emitters and lenses to heat discrete portions of the substrate
Data Source
AI summary
An apparatus includes a processing chamber, a substrate support in the processing chamber, a plasma source coupled to the processing chamber, and a plurality of heating devices arranged on the processing chamber. Each heating device is configured to emit laser beam on a substrate positioned on the substrate support to heat the substrate.