Unique metal lift-off process for the LED manufacturing industry


At the beginning of 2017 the AP&S metal lift-off process, which was launched in 2012 and runs successfully at several AP&S key customers sites within Europe today, was further developed and adjusted for the use in LED production.

“The lighting market is of high interest for our company. The semiconductor-based technologies like LEDs are on the rise and manufacturers of LED lighting systems are looking for reliable partners offering them depth of technical expertise and efficient solutions. The AP&S range already includes several wet process tools for this industry. However, we decided to further develop our existing metal lift-off process in order to meet the specific requirements of the LED sector. Now we are able to offer our customers a revolutionary solution, perfectly fitting to their key challenges like automated high volume production, prevention of damages on the substrate and ensuring of highest quality results”, says Uwe Müller, Director Business Unit Single Wafer.

The AP&S metal lift-off process is a single wafer spin process, offering three outstanding USP’s: 

  1. Superb solvent performance, without impact on substrate and structures
  2. Use of DMSO (dimethyl sulfoxide), an EH&S uncritical substance (EU & US)
  3. Optimized 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 commonly used technology for performing lift-off is based on the single wafer spin clean, which requires mandatory pre-soak and high temperature for solvents. Further disadvantage of these equipment 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.

By using DMSO at elevated temperatures combined with Megasonic agitation AP&S metal lift-off process offers high safety for workers, environment and equipment and guarantees a constant solvent performance over an extended period. The process 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. All interested parties are welcome to test the AP&S metal lift-off process in the AP&S demo center, an in-house application laboratory at the company’s headquarters in Donaueschingen, Germany. “I look forward to welcome customers and potential partners in our demo center and to demonstrate them our unique metal lift-off process. Our whole process developing team is curious about receiving feedback concerning our specially adjusted solution for the LED market”, concludes Stefan Zürcher, responsible Process Engineer.