Etching Silicon Wafers Without Hydrofluoric Acid

Hydrogen fluoride is an excellent etching chemical for silicon wet etching in wafer fabrication, etching rapidly to remove silicon oxide, for example, after an initial RCA clean. Although it is effective, hydrogen fluoride is toxic, dangerous and can be deadly if proper procedures are not followed.

Some of the dangers of exposure to hydrofluoric acid include:

• Vapor that can cause lungs to fill up with liquid
• Affects nerves at sites where the skin has been exposed to the acid and initially, the victims may feel a little pain as a result.
• Can penetrate deep into the body and destroy the tissues and bones. This often can cause long-lasting damage.
• Disrupts calcium chemistry of the blood, eventually leading to cardiac arrest.
• Even a small amount can cause skin burns that may be slow to heal. It can also result in death if treatment is delayed.

Hydrofluoric acid is also a hazardous waste and its discharge is tightly regulated. The acid must first be neutralized and the discharge limits on fluoride and metals must be followed. The safety and environmental considerations have resulted in the search for alternatives.

Depending on the specific silicon wet etching application, other etching chemicals may be used which are more suitable and safer replacements for hydrofluoric acid. Some of these include potassium hydroxide (KOH), tetramethylammonium hydroxide (TMAH) and nitride etch.

Modutek can help customers make the change by recommending equipment that supports an alternative chemical etchant. The company has over 35 years of experience and expertise in providing wet bench and wafer fabrication equipment and can advise customers about alternatives.

Read the complete article "Etching Silicon Wafers Without Hydrofluoric Acid" to get more details. If you have questions or would like a free quote or consultation, please contact Modutek at 866-803-1533 or email modutek@modutek.com.