How To Distinguish Material Selection Criteria Between Semiconductor Cleanroom-Grade And General Machine Tool-Grade Granite

   Growing demand for semiconductor inspection gear, lithography equipment, linear motor stages and precision machine tools has caused widespread confusion over granite selection. Many manufacturers supply ordinary machine-tool granite to semiconductor cleanrooms, triggering particle shedding, ion leaching, thermal precision drift and pore contamination that cut production yields. As a full-spectrum ultra-precision substrate supplier serving both cleanroom and general machining sectors, UNPARALLELED® develops quantifiable grading standards covering ore source, physical performance, cleanroom compatibility, processing and inspection to guide equipment makers.
   UNPARALLELED uses self-developed high-density black granite (≈3100kg/m³) for both grades, with separate ore screening rules.                                           
General machine-tool granite only needs compact rock without through cracks (density ≥2900kg/m³). Minor micro-pores are acceptable; basic natural aging suffices. It fits PCB drillers, standard CMMs and CNC bases, tolerating workshop dust and temperature swings.
   Cleanroom-grade granite requires premium homogeneous ore with water absorption ≤0.1% and no loose crystal clusters. It undergoes long-term natural aging plus staged constant-temperature stress relief to eliminate micro-deformation under temperature cycles. Radioactivity and metal ion leaching tests are mandatory to avoid wafer contamination. Unlike cheap marble or low-density granite from small factories that shed dust and cannot meet ISO 5/6 cleanroom standards, UNPARALLELED strictly classifies materials in line with its commitment of "No cheating, No concealment, No misleading".
   Physical indicators follow DIN, ASME, JIS and GB standards to separate the two grades.
   Machine-tool grade: linear expansion ≤7×10⁻⁶/℃, Mohs hardness ≥6.5, Shore hardness ≥70, Ra 0.32–0.63μm, complying with DIN876 Grade 0/1, focusing on rigidity and basic precision.
   Cleanroom grade: thermal expansion limited to ≤4×10⁻⁶/℃ with nano polishing (Ra ≤0.05μm) to reduce dust adhesion. Zero micro-pores deliver near-zero water absorption and no particle shedding after wiping. Higher damping suppresses micro-vibration for nanometer wafer positioning, with deformation kept below 0.5μm after 100 temperature cycles to stop long-run precision drift.
   Unique cleanroom compatibility tests only apply to cleanroom-grade granite:
   Particle emission test: particle counters measure 0.1μm particles after repeated wiping, with strict limits for cleanroom products.
Ion leaching test: low metal ion release prevents wafer short-circuit and lens fouling.
   Surface sealing: special low-outgassing coating fills micro gaps; machine-tool granite only gets simple polishing without sealing.
Processing environments draw clear distinctions.
   Machine-tool granite is machined in ordinary CNC workshops with common abrasives and coolants, mass-produced on four Taiwan Nante grinders for low-cost machine bases.
   Cleanroom-grade granite is fully processed in the 10,000㎡ Class 10,000 constant-temperature clean workshop with 1000mm thick anti-vibration concrete floor and 2m deep shock trenches. Silent overhead cranes and dust-free diamond abrasives are adopted, while 30+ year veteran grinders conduct nano mirror polishing. Workpieces age in isolated clean assembly zones with much higher production costs.
   Differentiated multi-stage outgoing inspection and traceability systems enable quick identification.
   Machine-tool granite receives three basic geometric tests (size, flatness, verticality) via standard Mitutoyo gauges with simple dimensional reports.
Cleanroom-grade granite undergoes full traceable testing including particle emission, ion leaching, water absorption and thermal deformation.                Measuring equipment such as Mahr 0.5μm dial gauges, Renishaw laser interferometers and WYLER levels are traceable to provincial and municipal metrology institutes. Each workpiece carries a unique serial code storing full lifecycle test records to pass strict semiconductor supplier audits.
Equipped with ISO triple system, CE certification and over 20 global patents, UNPARALLELED supplies two granite grades worldwide. Machine-tool grade products serve Bosch, THK, HIWIN and domestic CNC manufacturers; cleanroom-grade substrates support Samsung, Apple, Akribis, STI Semiconductor and Flex for perovskite coating, femtosecond inspection, AOI and X-ray clean lines. The R&D team cooperates with NUS, Changchun Institute of Optics and global metrology institutes to update cleanroom grading standards annually.
   Adhering to the quality policy "The precision business can't be too demanding" and the spirit "Dare to be first; Courage to innovate", UNPARALLELED will standardize granite grading to eliminate mixed material application, reduce precision loss and cleanroom pollution, and advance the global ultra-precision industry to fulfill its mission of promoting ultra-precision industrial development.