Plasma Process Run-to-Run Control with Dynamic Variable Addition
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Solution Overview
Problem
Plasma processing apparatuses face challenges in maintaining stable process performance due to fluctuations in process conditions, leading to interruptions and reduced operating rates, as existing Run-to-Run control methods often result in parameter corrections exceeding defined limits, causing control errors and process failures.
Innovation Solution
A plasma processing apparatus and method utilizing N+1 correction amount calculating units and N manipulated variable adding units to dynamically adjust parameters within defined limits, allowing for stable process performance without interrupting plasma processing, by prioritizing manipulated variables and adding additional variables when necessary to prevent parameter exceedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Run-to-Run control is applied to correct recipe parameters for each processing cycle, then process performance stability is improved, but control errors occur when correction amounts exceed parameter limits
Solution Approach 1:
The patent implements dynamic manipulation variable addition, where the system adaptively adds new manipulation variables (such as gas flow rates, pressure, or power parameters) based on real-time process conditions. When existing variables reach their correction limits, the system dynamically introduces additional variables to continue achieving process performance targets without exceeding parameter boundaries, thereby maintaining both reliability and precision.
Solution Approach 2:
The system changes the set of manipulation variables available for control. By adding new manipulation variables to the control system, it expands the degrees of freedom for recipe correction. This allows the system to find alternative parameter combinations that achieve the desired process performance without any single parameter exceeding its defined limits, thus resolving the contradiction between stability and precision.
2Productivity
If parameter corrections are applied to maintain process performance, then operating rate is improved, but process interruptions occur due to control errors
Solution Approach 1:
The system performs preliminary identification of additional manipulation variables before they are needed. By proactively determining potential backup variables and their relationships with process outcomes, the system ensures that when control errors occur or parameters approach limits, the additional variables are already prepared and can be immediately activated to maintain process continuity without interruptions.
Solution Approach 2:
The patent implements a cushioning mechanism by having standby manipulation variables ready before control errors occur. These additional variables act as a buffer or safety margin, preventing process interruptions by providing alternative control pathways when primary parameters reach their correction limits or cause control errors.
3Adaptability or versatility
If multiple manipulation variables are used for control, then flexibility is improved, but system complexity increases
Solution Approach 1:
The patent segments the manipulation variables into primary and additional categories. The primary variables are used for normal operation, while additional variables are maintained as backups or supplements. This segmentation allows the system to maintain simplicity during routine operation while having the flexibility to activate additional variables when needed, thus balancing adaptability with manageable complexity.
Solution Approach 2:
The additional manipulation variables are designed to serve multiple functions: they can act as backup variables when primary variables reach limits, as supplement variables to enhance control precision, or as alternative control pathways when control errors occur. This multi-functionality allows the system to maintain flexibility without proportionally increasing complexity, as the same additional variables serve multiple control needs.
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
Enables uninterrupted plasma processing with minimized control errors, ensuring stable process performance results and maintaining high operating rates by effectively managing parameter corrections within predetermined ranges.
Implementation Method 1
introduce plasma generation gas into the processing chamber and generate plasma
Implementation Method 2
plasma generation gas into the processing chamber and generate plasma
Data Source
AI summary
Method for carrying out plasma processing on a wafer under Run-to-Run control by using a plasma processing apparatus having a plasma processing chamber, a process monitor which monitors a condition in the plasma processing chamber, and an actuator which controls parameters which are constituent elements of a plasma processing condition. The method includes the steps of making one of the parameters a (N−1)th manipulated variable, calculating a first difference between a process monitor value in the plasma processing obtained by the process monitor and a desired value of the process monitor value in the plasma processing, calculating a correction amount of the (N−1)th manipulated variable on the basis of the first difference and a previously obtained correlation between the process monitor value in the plasma processing and the (N−1)th manipulated variable, wherein N is a natural number equal to or larger than 2.