Otherwise, the next step removes the wrong areas of the substrate, resulting in an ineffective product. As with any production step in the photolithography process, precision is key to achieving the desired results in the development phase. The concentration of the photoresist developer (e.g. TMAH) should be within an optimal range to effectively remove the photoresist in the intended area.
For example, a typical TMAH solution should have a concentration between 2.38% and 2.62%. An accurate real-time analyzer helps keep chemical properties under control and working effectively.
Wet etching step
Wet etching (or isotropic etching) is a rapid method of etching materials. Companies use various types of chemicals to create a pattern on the substrate of a given material (usually silicon wafers). Currently, there is a trend towards smaller and more compact chipsets, therefore the challenge of this process is to create more precise and complex patterns on the substrate using the right chemical concentrations.