Wet chemical processes
Wafer cleaning is commonly the first step and may be used repeatedly throughout a process fabrication sequence. This may involve the use of acid and basic solutions, followed by a water rinse.
Cleans are designed to remove organic or metallic surface contamination as well as particulates. Furnace pre-cleans consist of a Piranha clean followed by silicon clean 1(SC1) and then silicon clean 2(SC2). Short etch steps are often done prior to metallization to ensure good contacts to semiconductors. Micro Electro-Mechanical Systems (MEMS) processes can utilize a long buffered oxide etches (BOE) for the release step.
Wet chemical etching is available with the following chemicals:
- Buffered oxide etch (BOE = NH4F + HF) and HF solutions (such as 10 parts H2O + 1 part 49%HF)
- NH4OH + DI H20
- DIH2O + HNO3 + H3PO4 + C2H4O2 (Moly and Al Etching)
- DIH2 + HNO3 + HCL ( ITO Etching)
- PCT Megasonic clean (can be used with Detergent8 soap or without)
- Each chemical tank has a QDR rinse tank associated with it.
- Spin Rinse Dryer to Dry the wafers after rinse
- SRS Solvent Strip chemistry
Equipment and hoods
- One acid hood
- One solvent hood
- Other chemistries can be used. Please check with FEDC staff.
- Wafer cleaning