Laser Polishing Pad Conditioning Device
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Solution Overview
Problem
Existing methods for conditioning polishing pads in semiconductor wafer processing result in non-uniform roughness and shortened pad lifetime due to uneven cutting and potential debris creation, leading to defects in substrates.
Innovation Solution
A laser-based conditioning device that emits a beam with a wavelength range non-reactive to polishing fluids but reactive with the pad material, allowing for controlled and uniform conditioning of the polishing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an abrasive conditioning disk is used to condition the polishing surface, then the polishing surface can be roughened, but the roughness across the polishing surface becomes non-uniform
Solution Approach 1:
The patent replaces the mechanical abrasive conditioning disk system with an optical laser system. The laser beam conditions the polishing surface through optical energy rather than mechanical abrasion, eliminating the non-uniform roughness problem caused by uneven cutting of the abrasive disk while achieving consistent and uniform surface conditioning.
Solution Approach 2:
The patent changes the conditioning mechanism from mechanical (abrasive disk) to optical (laser beam). By adjusting laser parameters such as wavelength, power, and scanning speed, uniform conditioning is achieved without the variability inherent in mechanical abrasive systems. The laser parameters are controlled to ensure consistent energy delivery across the polishing surface.
2Manufacturing precision
If optical energy (laser) is used to cut into the polishing surface, then conditioning can be achieved, but the optical energy interacts with polishing fluids causing boiling and pore rupture
Solution Approach 1:
The patent carefully selects and controls the laser wavelength parameter to be non-absorptive by the polishing fluid. This parameter change allows the laser energy to pass through the fluid without causing boiling, while still being absorbed by the pad material to achieve the desired conditioning effect. The wavelength is optimized to differentiate between fluid and pad interaction.
Solution Approach 2:
The laser wavelength acts as an intermediary that selectively interacts with the pad material while being transparent to the polishing fluid. This intermediary property allows the laser energy to condition the pad surface without transferring harmful thermal effects to the fluid, avoiding pore rupture and maintaining process stability.
3Manufacturing precision
If abrasive cutting is used to condition the pad, then the polishing surface can be roughened, but large asperities are produced that may break loose and create substrate defects
Solution Approach 1:
The patent replaces mechanical abrasive cutting with optical laser ablation. This substitution eliminates the generation of large asperities that characterize mechanical cutting, as the laser removes material through vaporization rather than mechanical fracture. The result is a conditioned surface without loose debris particles that could contaminate substrates.
Solution Approach 2:
The patent converts the potential harm of excessive material removal into a benefit by using controlled laser ablation. The laser energy is precisely controlled to remove only the necessary amount of pad material to create the desired surface profile, avoiding the creation of large asperities while still achieving effective conditioning. The process transforms what could be harmful over-cutting into precise, controlled material removal.
4Manufacturing precision
If fluid jet systems are used to condition the polishing pad, then conditioning can be achieved, but great amounts of fluid are consumed and operating costs increase
Solution Approach 1:
The patent replaces the fluid-based jet conditioning system with an optical laser system. This substitution eliminates the need for large volumes of conditioning fluid, thereby reducing fluid consumption and associated operating costs while maintaining effective pad conditioning through optical energy delivery.
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
The solution achieves uniform conditioning of the polishing pad, reducing debris and extending pad lifetime while maintaining a consistent removal rate and surface quality.
Implementation Method 1
an optical device comprising a laser emitter adapted to emit a beam toward a polishing surface of the polishing pad
Implementation Method 2
the beam having a wavelength range that is substantially non-reactive with a polishing fluid utilized in the polishing process, but is reactive with the polishing pad
Data Source
AI summary
A method and apparatus for conditioning a polishing pad is provided. In one embodiment, a pad conditioning device for a substrate polishing process is provided. The pad conditioning device includes an optical device coupled to a portion of a polishing station adjacent a polishing pad, the optical device comprising a laser emitter adapted to emit a beam toward a polishing surface of the polishing pad, the beam having a wavelength range that is substantially non-reactive with a polishing fluid utilized in the polishing process, but is reactive with the polishing pad.