Process Analysis and Topography Evaluation for Monocrystalline Silicon Laser Cutting-Off.

Area of Science:

• Materials Science
• Manufacturing Engineering
• Laser Processing

Background:

• Monocrystalline silicon's brittleness and low fracture toughness pose challenges for high-precision cutting.
• Efficient wafer cutting is crucial for semiconductor manufacturing.

Purpose of the Study:

• Investigate the impact of laser process parameters on groove dimensions and the machining affected zone (MAZ) during monocrystalline silicon cutting.
• Determine optimal laser processing conditions for improved cutting quality and efficiency.

Main Methods:

• Systematic variation of laser cutting parameters including cutting times, scanning speed, laser frequency, and pulse width.
• Analysis of groove width, machining affected zone (MAZ) size, and recast layer formation.
• Evaluation of surface quality after post-processing wiping.

Main Results:

• Laser cutting creates a groove and a surrounding MAZ, both affecting cutting quality.
• Post-processing wiping effectively removes thermal products, eliminating the MAZ and recast layer, restoring the surface.
• Increasing cutting times initially widens the groove but shows complex behavior beyond 80 passes.
• Lower scanning speed and increased laser frequency generally enlarge groove/crack width but reduce MAZ.
• Laser pulse width impacts quality irregularly, with 0.3 ns yielding the best results.

Conclusions:

• Laser process parameters significantly influence monocrystalline silicon cutting quality.
• Post-processing wiping is a viable method to enhance cutting quality by removing the MAZ and recast layer.
• Optimizing parameters like cutting times, speed, frequency, and pulse width is essential for efficient and high-quality laser cutting.