Spin Etching

Spin etching for post-treatment after wafer thinning. Wafer thinning (backside grinding) is a key step in IC and MEMS fabrication, used to:

• Achieve the required device thickness (ICs, MEMS)
• Meet specific thickness requirements based on functionality (MEMS)
• Reduce substrate series resistance in vertical devices (power devices)

A study by Dr. K. Gottfried of Fraunhofer ENAS demonstrated that spin etching with HNO₃/HF/CH₃COOH on a POLOS^® Advanced Spin Station successfully removed 10 µm of silicon, while almost completely eliminating grinding-induced substrate damage.

Compared to CMP, this spin etching method offers:

• A simple, cost-effective process setup
• Significantly faster processing times
• High and tunable etch rates
• The ability to process backside-ground wafers directly, without additional cleaning

Standard capabilities:

• Compatible with 100 mm, 150 mm, and 200 mm wafers
• Minimal conversion time (< 15 minutes)
• Supported chemicals
  • KOH
  • HNO₃/HF/CH₃COOH (HNA)
• Continuous wafer rotation
• Puddle mode processing
• Flexible dispense options
  • Fixed position
  • Oscillating movement over wafer diameter
  • Spray dispense
  • Flush dispence

System requirements:

• Spin Wet Station

Recommended models:

• Up to 150 mm*
• Up to 200 mm*
• Up to 300 mm*

* All units support puddle etching with adjustable spin speeds from 1 to 7,000 rpm, and programmable chuck rotation in both clockwise and counterclockwise directions.