PV Material Process Equipment
DESIGNED FOR THE PV INDUSTRY
Wafab International offers several types of tools for silicon processing:
- Silicon raw materials cleaning – etching and cleaning of raw silicon “chunks”
- Silicon substrate etching and cleaning – for blank solar substrate materials
- Solar cell cleaning, etching and surface preparation – for surface treatment of printed solar cells
Silicon “chunk” cleaning – usually requires a dilute cleaning solution with ultrasonic agitation capability. Typical process sequence is a multistep process including initial clean and rinse with ultrasonics, dilute acid wash, final rinse and dry. Similar tools are also used to clean scrap material from the ingot process – where “tops” and “tails” of the silicon ingots are collected and chemically processed and reclaimed previous to remelt into the crystal growing/ingot pulling tools. Wafab process tools may provide high volume processing of loads up to 450 lbs. using special robot assist mechanisms.
Throughput volumes range from 600 to 2,000+ pieces per hour using robot-assisted equipment. All process chemicals are automatically dispensed, monitored and maintained within the process tanks in such cases. Frequently multiple cassettes are processed simultaneously in order to provide maximum throughput.
Silicon substrate processing – is required for the blank poly or monocrystaline Si substrates after wire sawing, previous to final solar circuit processing. In this process blank substrates are removed from the wire saw carrier bar and then placed into process cassettes. Typically blank substrates are loaded into either 50-piece or 100-piece carriers and then processed through a series of chemical tanks using a robotic device. For small volume R&D type applications a simple manually loaded process station may be adequate.
Typical process flows involve a series of brief chemical treatments, rinses and drying steps. Wafab provides all the tools required for such applications including a wide range of chemical handling equipment, process fixtures and process tools.
Solar cell processing – follows after the solar cellcircuitry is printed or otherwise applied onto the blanksilicon substrates. In this final manufacturing step finished solar cells may be final cleaned or specially treated using process tools which are similar in design to the previously described blank silicon processing equipment.