Acid Bench 02
Acid Bench 02 is used for acid processing on CMOS-clean wafers for a variety of purposes. The Buffered HF (BHF) tank and dilute HF tanks (users set the concentration) are generally used for wet etching of silicon dioxide selective to silicon. The hot phosphoric tank is generally used for selective wet etching of silicon nitride selective to silicon dioxide and/or silicon. The Nanostrip tank is generally used for wafer cleaning and/or removal of positive photoresist from silicon wafers.
|Acid Bench 02|
|Technology||Wet chemical processing|
|Materials Restriction||CMOS Clean|
|Sample Size||4" and 6" wafers|
|Supported Processes||Supported Processes|
- Update this with announcements as necessary
- Please do not change nanostrip between 9:30-11:00 on Mondays. There are 2 scheduled tank changes in the lab during that time, and doing an extra tank will overwhelm the AWN.
- Buffered HF (BHF)
- Phosphoric acid
- Hydrofluoric acid (HF)
- Sulfuric acid (H2SO4)
- Hydrogen peroxide (H2O2)
- Hydrochloric acid (HCl)
|Warning:||You must use the buddy system for all chemical processing. No processing if you are alone in the lab. If the yellow warning lights are on it means that there are 2 or 1 people in the lab.|
Working with chemicals can be very dangerous. Chemicals used at this bench are some of the most hazardous in the lab. To minimize the chance of accident, make sure you always:
- Wear proper PPE at the bench. This includes apron, faceshield, and Trionic gloves
- LNF Glove Policy
- Know the properties and hazards of chemicals you are working with. If you don’t know, find out by reading about them or asking staff.
- Plan the details of your process. Before you start working, plan what quantities of chemicals and sample carriers you will use. Plan how you will rinse your sample and what you will do with any waste generated. Make sure you know how the controllers work.
- Only process 4” and 6” wafers.
- Do not use this bench without proper training
- Waste from this bench goes into the LNF's acid waste neutralization system and then to the city sewers. No solvents can be used or disposed of in this bench.
Acid Bench 02 consists of:
- Recirculating Buffered HF (BHF) tank
- Heated bath for etching with Phosphoric acid at 165 degrees Celsius for nitride etching
- Heated bath for Nanostrip cleaning and photoresist removal
- Unheated chemical bath for Hydrofluoric acid (HF) Etching
- A Quick Dump Rinse ("QDR") for rinsing wafers
- A Bottle wash station for rinsing empty acid bottles before disposal.
- 4 inch and 6 inch wafers
- Silicon Substrates ONLY
The Acid Bench 02 is designated as a CMOS Clean class tool. Below is a list of approved materials for the tool. Approved means the material is allowed in the tool under normal circumstances. If a material is not listed, please create a helpdesk ticket or email firstname.lastname@example.org for any material requests or questions.
LNF Standard Processes in this bench
- Buffered HF (BHF) for etching silicon dioxide
- Hydrofluoric acid (HF) for etching silicon dioxide
- Hot Phosphoric acid ("Hot Phos") for etching silicon nitride
- Nanostrip for cleaning wafers and stripping approved positive photoresists
- Piranha Etch for cleaning silicon wafers
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Standard Operating Procedure
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- Take the General Wet Bench Training, if you haven't already. Online training here: https://rise.articulate.com/share/vn2Zf8VUbSpxQ4KFh-snYwzwluJ7i24U
- Read through this page and the Standard Operating Procedure above.
- Practice with your mentor or another authorized user until you are comfortable with tool operation.
- Fill out Process Information Form. You will need to fill this out for each bench you plan on using.
- Open a Helpdesk ticket and request a checkout.
- A tool engineer will schedule a time for checkout.
- Complete the Acid Bench 02 quiz.
- If you pass the quiz the tool engineer will authorize you on the tool. If not you will be contacted to repeat. -->
- Buffered HF is changed on an as-needed basis when crystallization is observed or when etch rate changes considerably.
- Hot Phosphoric, and HF are generally user-maintained baths. Please fill out helpdesk ticket if you need training or assistance.
- Nano-strip Tank Change process can be found here and user done. Remember that if the nanostrip is over 1 week old, you should drain, rinse, and refill the tank.