Upgrades needed to process larger wafers, says VDMA

German engineering association the VDMA (Verbandes Deutsches Maschinenbau Anlage) has published an update to its annual International Technology Roadmap for Photovoltaics (ITRPV) report.

In the update, the organization notes the growing importance of wafer size to German PV equipment suppliers – with Chinese solar manufacturer Longi introducing a 166mm ‘M6’ wafer this year before Zhonghuan Semiconductor pushed an even larger format with the 210mm ‘kwafoo’ wafer it launched in August.

German solar production line equipment suppliers are watching developments in the wafer market closely, and the VDMA has indicated only wafer sizes smaller than the 161.7mm ‘M4’ size can be processed on existing lines without modification. The engineering association says wafers on a 166mm-plus scale will require new lines for both mono and multicrystalline technologies, and for both cell and module production.

Throughput fears

In its report, the VDMA also found disparities in the throughput of various stages of cell production, presenting another potential barrier to cost reductions. The ITRPV study found chemical processes – batch and inline – are set to achieve throughputs approaching 9,000 wafers per hour by 2021 while processes such as metallization, classification and thermal processing are struggling to reach 6,000 per hour.

The report says the disparities could continue for the next decade, with wet chemical processes set to achieve rapidly increasing throughput up to 15,000 wafers per hour in 2029, challenging other stages to keep up. “A maximum of >10,000 wafers/hour is expected by 2023 for metallization and test equipment but this will require significant engineering efforts,” reads the report. “Thermal processing is expected to somewhat lag in terms of throughput. So innovative equipment/process solutions for increased throughput in thermal processing are required.”