ChemicalWasteDisposalforBOESOP
Document ID: HF-WASTE-001 Process: Silicon Dioxide Wet Etching Waste Handling Location: HackerFab Wet Chemistry Lab - ESC 232
1. Purpose
To ensure the safe collection, storage, and disposal of buffered oxide etch (BOE) waste generated during silicon dioxide wet etching processes.
This SOP minimises risks associated with toxic fluoride exposure, corrosive chemical handling, and environmental contamination.
2. Scope
This procedure applies to:
HF solutions used for oxide etching
Buffered oxide etch (NH₄F + HF)
HF-contaminated rinse water
Any fluoride-containing liquid waste generated during the etching process
3. Responsibilities
Operator
Follow waste collection procedures
Label waste containers correctly
Report spills immediately
Process Lead / Lab Supervisor
Ensure proper containers and labels are available
Verify waste storage compliance
4. Required Equipment and Materials
HF-compatible waste container (HDPE or polypropylene)
Secondary containment tray (it catches chemicals if the primary container has leaks/spills)
Hazardous waste labels
PTFE or plastic funnels
HF spill kit
Calcium gluconate gel (for emergency exposure)
HF safe gloves; safety glasses
5. Waste Collection Procedure
Step 1 – Preparation
Ensure the waste container is made of HF-compatible plastic (never glass; HF dissolves glass).
Verify the container is placed in secondary containment.
Step 2 – Waste Transfer
After etching, transfer the used HF/BOE solution into the designated HF waste container using a plastic funnel.
Do not overfill containers (max ~80% capacity).
Step 3 – Rinse Waste
Collect any HF-contaminated rinse water in the same labeled waste container unless instructed otherwise by lab policy.
Step 4 – Labelling
Chemical contents: HF / BOE with fluoride ions
Hazard class: Corrosive, toxic
Date
Lab location
Responsible researcher
6. Storage Requirements
HF waste containers must:
Be stored in secondary containment
Remain closed when not in use
Be kept in the designated chemical waste storage area
Never be stored in glass containers
7. Waste Disposal
When the container approaches 80% capacity:
Seal the container.
Submit a hazardous waste pickup request through the institutional chemical waste disposal system (e.g., Waterloo ESF).
Store waste in the designated waste accumulation area until pickup.
8. Emergency Procedures
Chemical Spill
Evacuate area if necessary.
Use HF spill kit to neutralize and contain the spill.
Report incident to lab supervisor and safety office.
Skin Exposure
Immediately rinse affected area with running water for at least 15 minutes.
Apply calcium gluconate gel to exposed area.
Seek medical attention immediately.
9. PPE Requirements
Personnel must wear:
Lab coat
Chemical-resistant gloves (HF-rated)
Safety goggles
Face shield