LAM 9400/Processes/LNF Aluminum

From LNF Wiki
Jump to navigation Jump to search

About this Process
Process Details
Equipment LAM 9400
Technology RIE
Material Aluminum
Mask Materials Photoresist, SiO2
Gases Used BCl3, HBr
Date Created November 2018
Authored By Ashley Jian & Shawn Wright

This is a fast anisotropic aluminum etch.

Etch Profile

LAM 9400 Aluminum 500nm.png
LAM 9400 Aluminum 700nm.png
LAM 9400 Aluminum 3000nm.png

Etch Rates

These were measured using 1cm pieces on a 6" Si carrier. At this point we have limited data on how stable these etch rates are.

Main Etch

  • Aluminum: 536 nm/min
  • ALD Al2O3: 11 nm/min (49:1)
  • SPR: 41 nm/min (13:1)
  • SiO2: 36 nm/min (15:1)
  • PMMA: 36 nm/min (15:1)
  • ZEP: 29 nm/min (18:1)

Break Through

The breakthrough step is typically set to ~10 seconds, or enough time to get through any native oxide on the aluminum.

  • Aluminum: 88 nm/min
  • ALD Al2O3: 28 nm/min
  • SPR: 29.6 nm/min
  • SiO2: 48.4 nm/min
  • PMMA: 73.4 nm/min
  • ZEP: 49.4 nm/min
  • GaN (N-Polar): 18.7 nm/min

SF6 Ash

This is a short ashing step intended to replace Cl embedded in the sidewalls of the features with F in order to reduce how much corrosion happens when the sample encounters moisture in the air. Even small amounts of Cl on the surface of aluminum can form a HCl corrosion cell that can continually corrode aluminum. Below is an example of HCl corrosion on aluminum. It can also help to go from the etch directly into a DI water tank or QDR to attempt to rinse off any HCl.

Aluminum corrosion on lines.jpg


Parameter Break Through Main Etch SF6 Ash
Pressure 5 mTorr 20 mTorr 20 mTorr
TCP Power 600 W 600 W 400 W
Bias Power 50 W 50 W -
HBr Flow 25 sccm 40 sccm -
BCl3 Flow 25 sccm 10 sccm -
SF6 Flow - - 90 sccm
O2 Flow - - 10 sccm
Time 10 sec (typ) Variable 20 sec (typ)