Specific Process Knowledge/Etch/DRIE-Pegasus/Pegasus-4/Slow etch

The slow etch

This work is done by Berit Herstrøm @Nanolab.dtu, is nothing else is stated The slow etch is designed to etch slow at low powers to etch thin films and to avoid overheating of samples mounted on a carrier with Capton/polyimide tape

Parameter	Recipe name: Slow Etch	Recipe name: Slow Etch2
Coil Power [W]	350	200
Platen Power [W]	25	50
Platen temperature [oC]	20	20
H2 flow [sccm]	15	15
CF4 flow [sccm]	30	30
Pressure [mTorr]	3	10

Typical results	Slow Etch	Slow Etch2
Etch of SRN	~43nm/min [measured 39-50 nm/min over a 6" wafer]	23-25 nm/min [4" on carrier]]
Etch rate of Si3N4	~49 nm/min [4" on carrier]	24-26 nm/min [4" on carrier]
Etch rate of SiO2	~42nm/min [41-43 nm/min over a 6" wafer]	13.7-14.7 nm/min [4" on carrier]
Etch rate of Mir resist]	~nm/min	~17 nm/min
Tested etch time without burning the resist	3 min	30 min
Profile [o]

• Map of etch rate measurements for 'Slow Etch'
• 
  Etch rate map of SiO2 etch on 6" wafer
• 
  Etch rate map of SRN etch on 6" wafer

• Map of etch rate measurements for 'Slow Etch2'
• 
  Etch rate map of Si3N4 etch on 4" wafer (on 6" carrier)
• 
  Etch rate map of SRN etch on 4" wafer (on 6" carrier)
• 
  Etch rate map of SiO2 etch on 4" wafer (on 6" carrier)
• 
  Etch rate map of Si etch on 4" wafer (on 6" carrier)