The surface micro-quality of semiconductor equipment granite bases, characterized by nanoscale roughness, zero micro-defects, ultra-high cleanliness, non-magnetic and contamination-free properties, and uniform micro-morphology, directly determines wafer yield and long-term equipment stability.
I. Surface Roughness (Core Indicator)
Working Surfaces (Benchmarks / Guides / Vacuum Surfaces): Ra ≤ 0.01–0.05 μm (10–50 nm); High-end lithography machines / inspection platforms require Ra ≤ 0.01 μm (10 nm), mirror finish, no tactile sensation when touched.
Non-working Surfaces / Sides: Ra ≤ 0.2–0.5 μm, free of tool marks and grinding traces.
Measurement: Full inspection using high-precision roughness meters (precision 0.01 μm) or white light interferometers.
II. Microscopic Defects (Zero Tolerance)
No cracks, pores, pinholes, chipped edges, pits, scratches, tool marks, or residual grinding particles.
Microscopic Inspection (Electron Microscope): ≤3 defects >1 μm per square centimeter; free-floating particles strictly prohibited.
Edges / Holes: Uniform chamfer C0.5–C2, free of burrs and sharp angles to prevent flaking and wafer contamination.
III. Cleanliness and Surface Contaminants
Free of dust, stone powder, water stains, oil stains, fingerprints, and residual protective agents.
No oil seepage, efflorescence, yellowing, or exudates; suitable for Class 1–100 cleanrooms.
Protection: Use only food-grade, non-volatile, dust-free specialized protective agents; ordinary industrial protection prohibited.
IV. Micro-Morphology and Consistency
Uniform micro-peaks and valleys, no waviness, no undulations, no local protrusions/depressions.
Consistent gloss on the same working surface, no light/dark sides, no color difference; uniform micro-texture direction.
Flatness: Grade 000, ≤1 μm/m; flatness of any 100×100 mm area ≤0.5 μm.
V. Non-Magnetic Properties and Material Purity
Stone free of ferromagnetic minerals, impurities, white veins, yellow lines, pores, and porosity.
Premium Jinan Green / Indian Black: Ultra-fine grain, uniform blackness, density ≥2.7 g/cm³, water absorption rate <0.1%.
VI. Critical Process Assurance
Processed in a constant temperature workshop (20±0.1℃) with full-process wet dust-free grinding.
Post-grinding: High-pressure pure water rinse → dust-free drying → dust-free packaging; full-process cleanliness control.
Summary
Nanoscale mirror finish roughness, zero microscopic defects, ultra-high cleanliness, non-magnetic and contamination-free properties, and uniform micro-morphology are the hard requirements for semiconductor granite bases.
