Why High Temperature Quartz Baths Are Required for Silicon Wafer Cleaning

Silicon wafers undergo many process steps during the manufacture of semiconductor components. Cleaning the wafers properly is a key factor for successful fabrication. These process steps include etching and diffusion, both of which involve the use of a masking material which helps guide the etching chemicals or diffusion targets. When the cleaning is done, the masking material is removed. If traces of contaminants are left or introduced, it will result in an inferior and defective semiconductor product.

Aggressive chemicals are used in silicon wafer cleaning to remove organic masking material and other possible impurities. In this cleaning application, there needs to be a container that can resist the action of these aggressive chemicals, while remaining inert so as not to become the source of contamination itself.

 Quartz baths provide an ideal solution to the challenges of silicon wafer cleaning and for maintaining the high levels of wafer cleanliness. They provide a clean and safe container for silicon wafer cleaning because they can withstand the chemical reactions. Quartz baths typically hold the wafers and the cleaning chemicals, but some processes require heating, circulating the solution or adding chemicals, depending on the various materials used.

Quartz baths are impervious to strong chemicals such as hydrochloric acid, sulfuric acid, and hydrogen peroxide. The baths remain unaffected by these chemicals while the chemicals clean the silicon wafers. With SPM clean, sulfuric acid and hydrogen peroxide are mixed at a constant temperature of 100 degrees centigrade. Periodic spiking of hydrogen peroxide is necessary because it decomposes in the solution. This mixture of these strong chemicals, combined with high temperature, effectively cleans the silicon wafer without affecting the quartz bath container.

The electrical and physical structures that make up the semiconductor components are ultra-sensitive to contaminants. Even a single contaminant can interfere with the entire etching or diffusion process. Such interference from these contaminants can reduce the yield of the semiconductor components and affect the productivity of the semiconductor manufacturing facility. That is why it is extremely important to use bath containers for these process steps — they should be inert and should not become another source of contamination themselves.

If you would like more information about Modutek’s quartz baths, read the complete article “Why High Temperature Quartz Baths Are Required for Silicon Wafer Cleaning”. Contact Modutek at 866–803–1533 for a free consultation to discuss your needs.