AP&S adapts metal lift-off process for LED production
The company's metal lift-off process is a single wafer spin process, that is said to offer a number of important benefits. These include good solvent performance, without impact on substrate and structures; the use of DMSO (dimethyl sulphoxide), an EH&S uncritical substance (EU & US); and an optimised process time with an positive impact to the overall throughput
Common wet chemical lift-off processes work with batch immersion or spray application, which often cause critical residues and x-contamination, such as metal flakes. Another widely used lift-off technology is based on the single wafer spin clean, which requires mandatory pre-soak and high temperature for solvents.
Another disadvantage of these technologies is the use of chemicals like NMP (n-methyl-2-pyrolidone) or Acetone. NMP is an EH&S critical substance, which causes severe irritation at skin, eye area as well as in respiratory system and carries the risk to damage fertility and harm unborn child. Acetone is highly flammable and residues after processing with acetone represent a well-known problem.
AP&S says that by using DMSO at elevated temperatures combined with Megasonic agitation, its metal lift-off process offers high safety for workers, environment and equipment and it guarantees a constant solvent performance over an extended period. The process also guarantees damage free lift-off for sensitive applications and sensitive substrates.
There are no residues left on the substrate after processing and DMSO substance itself is easy to rinse off with DI water or lower solvent. For the AP&S customers it means low chemical consumption, cost reduction in the production chain and enhanced process capability.
The AP&S lift-off solution is available for all types of metal layers, alloys and further protection layers used in the semiconductor industry.
Companies can test the metal lift-off process in the AP&S demo centre, an in-house application laboratory at the company's headquarters in Donaueschingen, Germany.