How Process Controls Improve KOH Etching Results

Potassium hydroxide etching, or KOH etching, is a process for creating silicon microstructures. It is widely used because it etches quickly, and can be set to etch at different speeds in different directions. For instance, technicians may want to etch downward into the silicon wafer more quickly than etching in a horizontal direction. They may want to create a rectangular shape, when the long side has a different etch rate compared to the short side.

The etching direction is influenced by the crystal lattice orientation of the silicon wafer and the possible doping of the wafer with boron. The etching speed, on the other hand, depends on the KOH mixture concentration and the temperature. The concentration can vary from 10% to 50% with 30% KOH by weight representing a common value. The mixture is heated to between 60 to 80 degrees centigrade and held steady at the temperature that gives the desired etch speed. Given the correct crystal orientation, doping in the right places and the correct etch speed, the microstructures will be done at a given time.

Compared to other processes, KOH etching is less hazardous. It is a versatile process for creating silicon microstructures. However, precise and responsive controls are required to get superior results.

To achieve KOH etching results, the etching process has to be set up to include the above mentioned factors to produce the desired result every time the process runs.

Modutek’s Teflon tanks are designed to provide precise temperature controls and accurate support equipment that an effective KOH process requires. Wet bench equipment from Modutek can deliver the KOH mixture to the Teflon tanks at precisely the right concentration.

The precise controls mean that each rate remains exactly at the desired level. The dimensions of the silicon microstructures are etched exactly as intended and the KOH process delivers high-quality output. Modutek provides a full product line of wet bench processing equipment and can adapt the KOH etching tanks and other processing equipment to meet the needs of customers.

The complete article, How Process Controls Improve KOH Etching Results, provides additional information. If you have questions, contact Modutek at 866-803-1533 or email sales@modutek.com to request a free consultation to discuss your wet bench processing equipment needs.