Kao cleaning solutions are used to strip dry films in the manufacture of electronic components, such as those used in smartphones. More and more companies are turning to the dry film method of fabricating tiny circuit boards in order to meet the demand for ever more compact, high-performance, low-cost electronics (Figure 1).
In the dry film method, metal circuits are formed using resin film as a mold for microfabrication. The resin film need to be completely removed after processing, for any residual film may cause the component to malfunction. To aid stripping, particularly in microcircuitry, cleaners containing solvents are used to penetrate the resin and cause it to swell and peel off from the substrate, but such solvents are problematical from an environmental standpoint. By applying interface-control technology, Kao developed a selective stripping solution that achieves rapid penetration and outperforms other companies' products in stripping dry film (Figure 2) without attacking the resin of the core parts or the metal circuits. In addition, Kao's stripping solution has twice the durability of its competitors', which means less frequent exchange of solution and lower manufacturing costs. Moreover, by focusing on interfacial phenomena and mixture design, Kao achieved all this with a water-based solution that places a minimal burden on the environment.
Kao will continue to pursue development of precision cleaning technology based on interface science to support our advanced information society.
Figure 1. Circuit Board Fabrication Using the Dry Film Method
Figure 2. Stripping Performance (track width 15 microns, 3-minute immersion)