1 Housing
- Stable modular main frame, completely covered by PP-panels
- Main systems for bath management, electrical cabinets and process control units are integrated into housing
- Safety gas sensor system for detection of harmful gas concentrations (NOX, H2, HF)
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2 Load / Unload Conveyor
- Manual or automated feed-in and take-out of wafer carriers
- Integrated carrier buffer
- Safety interlock of human or automation interaction
- RFID transponder identification
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3 Central Robot Handling
- Automated AC servo booster handling system guarantees quick, reliable and gentle carrier motion
- Up to 3 parallel working x-z-robots
- Sensitive crash protection sensor system
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4 Pre-Cleaning, Saw Damage Removal
- Initial cleaning and surface conditioning of incoming wafers material in hot alkaline cleaning mixtures
- Optional ultrasonic power integration for improvement of cleaning efficiency
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5 Alkaline Texturing (ALTEX)
- Preferably dedicated for texturing of monocrystalline Si wafers
- Removal of crystalline surface defects, forming random pyramides
- Uniform etching
- Compliant to international safety standards for atmospheres
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6 Acidic Texturing (ISOTEX)
- Preferred process for state-of-the-art texturing of multicrystalline Si wafers
- Removal of crystalline surface defects by using HF-HNO3 mixtures
- Excellent temperature control
- NOX-emmisson control during ongoing process and carrier transfer
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7 Porous Si-Etch (PorSi)
- Short dip-treatment in a cold alkaline solution etches off the thin layer of porous silicon, caused by previous isotexturing step
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8 Cleaning
- Using HF and HCl for effective removal of metal contaminations and native oxides
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9 Oxide etch (PSG removal)
- Removal of P-doped SiO2-layer from wafers, formed during previous POCl-diffusion
- Self-limiting ambient DHF etch step
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10 Rinsing
- Optimized rinsing technology in terms of
- Fresh water flow
- Partial water reclaim
- Mechanical support and temperature enhancements
- Intelligent combination of highly effective dump-spray rinse and water-saving multi-cascade overflow rinse
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11 Drying
- Stress-free 2-step drying process ensures perfect uniform, chemical and spot-free drying of wafers down to 150 μm with lowest risk of breakage
- Compatible with all common low surface carrier types
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12 Integrated Process Control
- Weight determination of wafer carriers pre- and post process for internal etch rate control
- Individual chemical bath management for filling and spiking of chemicals and DI-water
- Temperature control of all heated and cooled process steps
- Control of recirculation and injection flow rates
- Individual process time control
- Optional online/offline analysis of chemical compositions by titration, conductivity measurement and/or IR spectroscopy
- Resistivity measurement
- Process data storage and logging
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13 Central Machine Control Systems - Siemens SIMATIC S7 PLC system
- PC-based graphical user interface (WINCC)
- Bus systems for internal communication of sub-assembly systems
- OPC interfaces for external data exchange
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