Electrostatic Chuck Deflection Force Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor manufacturing, substrate supports often apply excessive clamping forces due to manufacturing variances, leading to defects such as craters, embedded particles, and film stress on workpieces, necessitating a more consistent and predictable clamping method to reduce defects.
Innovation Solution
A method utilizing a sensor assembly within an electrostatic chuck to monitor deflection forces on a workpiece, adjusting the chucking voltage and backside gas pressure to maintain forces below a threshold, and simultaneously ramping up these parameters to minimize the clamping force, thereby reducing defects and particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the target clamping force is increased to provide a factor of safety against manufacturing variances, then the reliability of workpiece holding is improved, but the workpiece is subjected to excessive clamping force causing damage and defects
Solution Approach 1:
The patent employs a feedback control system that uses a load cell to measure the actual clamping force applied to the workpiece. The control system compares the measured force against a target force and dynamically adjusts the chucking voltage to maintain the desired force level, eliminating the need for excessive safety margins while ensuring reliable workpiece holding
Solution Approach 2:
The system transitions from static, predetermined clamping force settings to dynamic adjustment of clamping force. The chucking voltage is continuously modified based on real-time feedback from the load cell, allowing the system to adapt to manufacturing variances without applying excessive force, thus resolving the contradiction between reliability and workpiece damage
2Stability of the object's composition
If manufacturing personnel increase the target clamping force to counter variances, then the consistency of workpiece holding is improved, but defects such as craters, embedded particles, and film stress increase
Solution Approach 1:
The load cell provides real-time feedback on the actual clamping force, enabling the control system to maintain consistent force levels without exceeding safe thresholds. This feedback mechanism ensures clamping force consistency while preventing the generation of defects such as craters, embedded particles, and film stress that result from excessive force
Solution Approach 2:
The patent replaces the mechanical approach of increasing clamping force with a control system approach. Instead of applying higher mechanical force to ensure consistency, the system uses electronic feedback and voltage adjustment to achieve force consistency, thereby eliminating the harmful effects of excessive clamping
3Reliability
If a factor of safety is applied to the target clamping force, then the sufficiency of clamping force is improved, but the chucking force becomes greater than necessary causing workpiece damage
Solution Approach 1:
The feedback control system using a load cell eliminates the need for safety factors by providing real-time verification of adequate clamping force. The system adjusts the chucking voltage to achieve the minimum necessary force for reliable workpiece holding, preventing excessive force application while maintaining sufficiency
Solution Approach 2:
The system changes the control parameter from a static target force with safety margin to a dynamic force level based on actual measurements. By continuously monitoring and adjusting the clamping force, the system maintains the minimum necessary force without requiring excessive safety margins, thus resolving the contradiction between sufficiency and force magnitude
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 effectively minimizes chucking forces on workpieces, reducing defects and particle generation, ensuring consistent and predictable clamping while maintaining secure holding during processing.
Implementation Method 1
An electrostatic force or other force ('clamping force') often is used to precisely hold the workpiece to a workpiece support surface of the substrate support
Implementation Method 2
A backside gas pressure is applied at a minimum pressure. The chucking voltage and or backside gas pressure is adjusted such that the deflection force is less than a threshold value
Data Source
AI summary
Embodiments disclosed herein include a method for minimizing chucking forces on a workpiece disposed on a electrostatic chuck within a plasma processing chamber. The method begins by placing a workpiece on an electrostatic chuck in a processing chamber. A plasma is struck within the processing chamber. A deflection force is monitored on the workpiece. A chucking voltage is applied at a minimum value. A backside gas pressure is applied at a minimum pressure. The chucking voltage and or backside gas pressure is adjusted such that the deflection force is less than a threshold value. And the chucking voltage and the backside gas pressure are simultaneously ramped up.