Photovoltaic wafer surface cleaning

What is wet chemical cleaning of wafer surfaces?

The wet chemical cleaning of wafer surfaces is required after several process steps in current state-of-the-art silicon solar cell production technology. Apart from the cleaning efficiency, process stability, cost, and throughput considerations have to be met.

How are solar cell wafers cleaned?

Therefore, cleaning processes for solar cell fabrication are often modified to achieve higher throughputs and lower cost of ownership. In the first treatment step (standard clean 1 – SC-1), the wafers are exposed to a hot mixture (75–85 °C) of ammonia/hydrogen peroxide/water (APM).

How to clean silicon wafers?

reason, different cleaning processes are analyzed in this section. A process developed by the RCA for microelectronics has become the standard for cleaning silicon wafers, which consists of a two oxidation steps followed by rinsings and HF dips to sequen-tially remove the organic and metallic impurities of the silicon surfaces.

What is photovoltaic silicon wafer manufacturing?

High quality and economic photovoltaic manufacturing is central to realizing reliable photovoltaic power supplies at reasonable cost. While photovoltaic silicon wafer manufacturing is at a mature, industrial and mass production stage, knowing and applying the fundamentals in solar manufacturing is essential to anyone working in this field.

How to remove organic contaminants from silicon wafers?

Removal of organic contaminants from silicon wafers can be accomplished by using strong oxidizing mixtures. The specific components and their volume ratio, as well as the oxidation process temperature (<130 °C), depend on the type of the organics to be destroyed.

How is photoresist deposited on a silicon wafer?

An etch mask containing SiO 2 or SiN x is deposited on the silicon wafer surface via thermal oxidation or PECVD. A photoresist is deposited on this layer through spin coating. The photoresist is dried and lithographically structured in regular distances with an accuracy of ~1 μm. The exposed areas are dissolved.