Laser Polishing Ceramic Surfaces for Semiconductor Processing
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Solution Overview
Problem
As-deposited ceramic coatings on semiconductor manufacturing equipment often have high surface roughness and porosity, leading to cracking, flaking, and particle contamination in plasma processing chambers, which can render devices inoperable and reduce yield.
Innovation Solution
Laser polishing methods using a pulsed laser beam with a frequency of 50 kHz or more and a spot size of 10 mm² or less are applied to ceramic substrates or coated substrates to reduce surface roughness and porosity, allowing for precision sub-millimeter scale polishing without substantial material removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If as-deposited ceramic coatings are used to protect processing components, then resistance to chemical corrosion and plasma erosion is improved, but surface roughness and porosity increase leading to cracking and flaking
Solution Approach 1:
The patent applies laser polishing with specific parameters (pulse frequency of 1-100 kHz, spot size of 0.1-10 mm, power density of 10-1000 W/mm²) to modify the surface parameters of ceramic coatings. This changes the physical state of the coating surface, reducing roughness and porosity while maintaining the protective properties of the ceramic material.
Solution Approach 2:
The patent replaces traditional mechanical polishing methods with laser-based surface modification. The laser beam scans across the ceramic surface, melting and re-solidifying the material to create a smooth surface without mechanical contact, thereby avoiding further damage to the brittle ceramic coating.
2Manufacturing precision
If traditional polishing methods are used on ceramic coatings, then surface roughness is reduced, but substantial material removal occurs compromising coating integrity
Solution Approach 1:
The patent replaces mechanical polishing with laser surface melting. The laser beam delivers controlled thermal energy to the ceramic surface, melting a thin layer that then re-solidifies as a smooth surface. This non-contact method removes minimal material while achieving the desired surface finish.
Solution Approach 2:
The patent utilizes the phase transition of ceramic material from solid to liquid and back to solid through controlled laser heating. The laser beam heats the surface above the melting point, creates a molten layer, and upon cooling, this layer solidifies with reduced roughness and porosity, preserving the underlying coating structure.
3Reliability
If high surface roughness ceramic coatings are used, then protective properties are maintained, but particle contamination occurs rendering devices inoperable
Solution Approach 1:
The patent modifies the surface parameters of the ceramic coating through laser polishing. By controlling laser parameters (pulse frequency, spot size, power density), the surface roughness is reduced from micrometer-scale to sub-micrometer-scale, eliminating the rough features that would otherwise generate particles during plasma processing.
Solution Approach 2:
The patent converts the inherently rough and porous nature of as-deposited ceramic coatings into a smooth, dense surface through laser-induced melting and re-solidification. The same material that initially causes particle contamination is transformed into a particle-free protective surface that maintains all the original protective properties.
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 laser polishing methods effectively reduce surface roughness by over 10% and porosity by over 30%, extending the lifetime of processing components by preventing cracking and flaking, and maintaining the integrity of patterned surfaces in plasma processing chambers.
Implementation Method 1
scanning at least a portion of the workpiece surface with a pulsed laser beam
Implementation Method 2
laser polishing methods using a pulsed laser beam with a frequency of 50 kHz or more and a spot size of 10 mm² or less are applied to ceramic substrates or coated substrates to reduce surface roughness and porosity
Data Source
AI summary
Embodiments of the present disclosure provide methods of laser assisted modification, i.e., laser polishing, of ceramic substrates, or ceramic coated substrates, to desirably reduce the surface roughness and porosity thereof. In one embodiment, a method of laser polishing a workpiece surface includes scanning at least a portion of the workpiece surface with a pulsed laser beam. The laser beam has a pulse frequency of about 50 kHz or more and a spot size of about 10 mm2 or less and the workpiece surface comprises a ceramic material.