Photolithography is an essential step in the manufacturing process of electronic semiconductor components. To create the necessary structures, substrates are coated with a photoresist and then exposed through a mask. The central component of the resist is usually a polymer whose chemical structure changes during exposure, making the resist locally soluble or insoluble in a selective solvent for the subsequent structuring steps.
The manufacture of increasingly compact and powerful electronic devices requires ever-higher component density, which in turn necessitates ever-smaller structures. This also places greater demands on the binder polymer in the photoresist, which must be capable of reproducing these structures, which can be as small as a few nanometers in size. In order to reproduce the structures sharply, it is advantageous if the polymer has a narrow molecular weight distribution and a high degree of purity (Fig. 1).
In a customer order, a manufacturing process was developed that allows well-defined polymers to be produced more easily and inexpensively than commercially available competing products. In addition, compared to the state of the art, this process allows the use of a large number of different monomers in order to individually adjust the properties of the resists, such as sensitivity, adhesion, etching stability, or solubility, according to customer requirements. The polymers produced using this process have also been optimized in terms of the temperature stability required for the process. The process has been granted a patent and is granted in the EU, US, JP, KR, and CN.
The results are summarized as follows:
These developments were pursued internally so that the polymers could be suitable for both positive and negative resists. The current status is TRL7. As part of Fraunhofer's internal AHEAD program, a company was founded to market the patented developments of Fraunhofer LBF under license: Supurior GmbH.
