Pressure Batch Compensation for CD Variation
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Solution Overview
Problem
In double patterning atomic layer deposition processes, material accumulation within the processing chamber leads to changes in impedance, causing wafer-to-wafer variability in critical dimension and imbalance, which is difficult to minimize due to non-uniform deposition and etching rates.
Innovation Solution
A controller system that determines an accumulation value and adjusts pressure or duration of etching/deposition steps based on stored data to maintain desired rates, using a polynomial correlation to compensate for material accumulation, thereby reducing wafer-to-wafer variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If deposition and etching processes are performed in the processing chamber, then material accumulation occurs on chamber surfaces, but this causes wafer-to-wafer variability in critical dimension and processing imbalance
Solution Approach 1:
The system performs preliminary characterization of material accumulation patterns on chamber surfaces before processing wafers. By pre-determining the accumulation values and their impact on deposition and etching rates, the controller can proactively adjust process parameters (pressure, temperature, gas flow rates) to compensate for the accumulated material, thereby maintaining critical dimension uniformity across multiple wafers without requiring chamber cleaning between each wafer
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors process outcomes and compares them against target specifications. Based on the observed wafer-to-wafer variability caused by material accumulation, the controller dynamically adjusts process parameters for subsequent wafers, creating a closed-loop control system that compensates for accumulation effects and maintains manufacturing precision over time
2Manufacturing precision
If material accumulation is compensated by adjusting process parameters, then wafer-to-wafer variability is reduced, but process complexity increases
Solution Approach 1:
The system compensates for material accumulation by systematically varying key process parameters including pressure, temperature, and gas flow rates based on pre-characterized accumulation models. These parameter changes are implemented through the existing process control system, allowing the patent to achieve wafer-to-wafer uniformity without adding complex hardware modifications. The controller selects and adjusts parameters from the current process set, leveraging existing system capabilities
Solution Approach 2:
The system uses its own process data and existing sensors to characterize and compensate for material accumulation effects. By analyzing process outcomes from previous wafers and using this information to adjust subsequent process parameters, the system performs self-diagnosis and self-correction without requiring external intervention or complex additional measurement systems, thereby reducing the overall complexity burden
Data Source
AI summary
A controller includes an accumulation determiner configured to determine a first accumulation value that indicates an amount of accumulation of material on surfaces within a processing chamber and a pressure controller configured to obtain the first accumulation value, obtain at least one of a setpoint pressure an etching step and a duration of the etching step, and, to control the pressure within the processing chamber during the etching step, adjust a control parameter based on (i) the first accumulation value and (ii) the at least one of the setpoint pressure and the duration of the etching step.