CMP Conditioner Load Sensor for Normal Force Control
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Solution Overview
Problem
The existing chemical mechanical polishing apparatuses face challenges in uniformly supplying slurry to a substrate due to inconsistent application of normal force on the platen pad, leading to clogged pores and reduced slurry delivery efficiency, which affects the lifespan of the platen pad and the polishing process.
Innovation Solution
A conditioner with a disk holder, piston rod, housing, and load sensor is used to measure and control the normal force applied to the conditioning disk, ensuring uniform force distribution and maintaining a predetermined force value, thereby evenly dispersing slurry on the platen pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a cylinder is used to apply downward force to the conditioning disk, then the platen pad surface can be cut, but the normal force becomes inconsistent causing uneven slurry supply
Solution Approach 1:
A load sensor is installed on the piston rod to detect the normal force applied to the conditioning disk in real-time, and this detection value is fed back to a controller that adjusts the pneumatic pressure to maintain consistent normal force
Solution Approach 2:
The traditional purely mechanical cylinder system is replaced with a system that incorporates a load sensor and controller to electronically monitor and adjust the normal force, transitioning from open-loop mechanical control to closed-loop electromechanical control
2Productivity
If pressure is continuously applied to the platen pad to maintain contact, then polishing can proceed, but the foaming pores become clogged obstructing slurry supply
Solution Approach 1:
The conditioner applies normal force intermittently through controlled pneumatic pressure cycles, allowing the platen pad pores to remain open for slurry supply while still achieving sufficient contact pressure for polishing when needed
3Productivity
If the conditioning disk is not pressurized with adequate force, then the platen pad pores remain closed, but excessive force shortens the platen pad lifespan
Solution Approach 1:
The load sensor provides real-time feedback on the normal force applied, allowing the controller to adjust pneumatic pressure to maintain the optimal force range that opens pores effectively without exceeding the threshold that would damage the platen pad
Solution Approach 2:
The system dynamically adjusts the pneumatic pressure parameter based on load sensor feedback to maintain the normal force within an optimal range, changing the pressure level as needed to achieve pore opening without excessive force
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 solution ensures consistent and efficient slurry supply to the substrate, extends the lifespan of the platen pad, and maintains a smooth chemical polishing process by uniformly cutting the platen pad and applying a controlled normal force.
Implementation Method 1
a load sensor installed to receive the normal force that the piston rod delivers and measuring the normal force
Implementation Method 2
a piston rod delivering a normal force to the disk holder
Implementation Method 3
a holder 32 is gripping a conditioning disk 31 contacting the platen pad 11... diamond particles attached on the surface thereof contacting the platen pad 11
Data Source
AI summary
Provided are a conditioner of a chemical mechanical polishing apparatus for polishing a substrate over a platen pad that rotates and a method thereof. The conditioner includes a disk holder, a piston rod, a housing, and a load sensor. The disk holder secures a conditioning disk that finely cuts a surface of the platen pad. The piston rod delivers a normal force to the disk holder. The housing covers at least a portion of the piston rod. The load sensor is installed to receive the normal force that the piston rod delivers to the piston rod and measuring the normal force.