Advantages of HF-Last Etching and IPA Drying in One Chamber

After cleaning, a silicon wafer needs to be effectively cleaned and dried with no particle contamination. Clean wafers are important to avoid errors in the next processing steps to produce devices that are of superior quality and free from defects. Using the single chamber HF-last and IPA vapor dryer show a considerable reduction in wafer substrate particle counts.

By the final stage of silicon wafer cleaning, the silicon oxide layer has to be removed and the cleaned wafer dried free from contaminants. However, transferring the wafers from the HF etching process to a separate drying chamber will likely cause the wafers to pick up particles.

Modutek now has a solution to this problem: the single-chamber HF-last and IPA vapor dryer, which can help to significantly reduce the particle count on wafer substrates.

In the single chamber process, Modutek uses IPA vapor drying in a free-standing unit with one DI water rinsing and drying. This method, also called the Marangoni drying technique, results in clean wafer substrates -- having no contamination or watermarks.

Modutek has modified the IPA vapor dryer to include HF (hydrofluoric) acid injection before the start of the standard IPA vapor drying process. The HF acid injection ratio is controlled and provides an etch to bare silicon. When the silicon is etched, it is then rinsed to a controlled pH level. Once the appropriate pH levels are reached, it is then followed by the IPA drying process without moving the silicon wafers. This results in the low particle count on the wafer.

Initial field results from the single chamber HF-Last IPA dyer that Modutek has supplied to customers are showing outstanding results. Within the 0.3 to 5 micron range, fewer than 20 particles (adders) were added to etched substrates which are substantially below what was achieved in previous processes in this field trail.

For more details read the complete article “Advantages of HF-Last Etching and IPA Drying in One Chamber” to learn more about Modutek’s IPA vapor dryers. Call Modtuek at 866-803-1533 or send an email to Modutek@modutek.com if you have questions or would like to get a free consultation.