Submicron patterned metal hole etching

Patent · Sat Jan 01 00:00:00 EST 2000

OSTI ID:873341

McCarthy, Anthony M ^[1]; Contolini, Robert J ^[2]; Liberman, Vladimir ^[3]; Morse, Jeffrey ^[4]

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1. Menlo Park, CA
2. Lake Oswego, OR
3. Needham, MA
4. Martinez, CA

A wet chemical process for etching submicron patterned holes in thin metal layers using electrochemical etching with the aid of a wetting agent. In this process, the processed wafer to be etched is immersed in a wetting agent, such as methanol, for a few seconds prior to inserting the processed wafer into an electrochemical etching setup, with the wafer maintained horizontal during transfer to maintain a film of methanol covering the patterned areas. The electrochemical etching setup includes a tube which seals the edges of the wafer preventing loss of the methanol. An electrolyte composed of 4:1 water: sulfuric is poured into the tube and the electrolyte replaces the wetting agent in the patterned holes. A working electrode is attached to a metal layer of the wafer, with reference and counter electrodes inserted in the electrolyte with all electrodes connected to a potentiostat. A single pulse on the counter electrode, such as a 100 ms pulse at +10.2 volts, is used to excite the electrochemical circuit and perform the etch. The process produces uniform etching of the patterned holes in the metal layers, such as chromium and molybdenum of the wafer without adversely effecting the patterned mask.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 6139716
• OSTI ID: 873341
• Country of Publication: United States
• Language: English

Related Subjects

submicron
patterned
metal
etching
wet
chemical
process
holes
layers
electrochemical
wetting
agent
processed
wafer
etched
immersed
methanol
prior
inserting
setup
maintained
horizontal
transfer
maintain
film
covering
tube
seals
edges
preventing
loss
electrolyte
composed
water
sulfuric
poured
replaces
electrode
attached
layer
reference
counter
electrodes
inserted
connected
potentiostat
single
pulse
100
10
volts
excite
circuit
perform
etch
produces
uniform
chromium
molybdenum
adversely
effecting
mask
counter electrodes
electrodes connected
electrochemical etching
metal layers
chemical etching
metal layer
counter electrode
process produces
single pulse
wetting agent
chemical process
wet chemical
submicron patterned
patterned metal
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