Method for making circular tubular channels with two silicon wafers

Patent · Mon Jan 01 00:00:00 EST 1996

OSTI ID:870689

Yu, Conrad M ^[1]; Hui, Wing C ^[2]

---

1. Antioch, CA
2. Campbell, CA

A two-wafer microcapillary structure is fabricated by depositing boron nitride (BN) or silicon nitride (Si.sub.3 N.sub.4) on two separate silicon wafers (e.g., crystal-plane silicon with [100] or [110] crystal orientation). Photolithography is used with a photoresist to create exposed areas in the deposition for plasma etching. A slit entry through to the silicon is created along the path desired for the ultimate microcapillary. Acetone is used to remove the photoresist. An isotropic etch, e.g., such as HF/HNO.sub.3 /CH.sub.3 COOH, then erodes away the silicon through the trench opening in the deposition layer. A channel with a half-circular cross section is then formed in the silicon along the line of the trench in the deposition layer. Wet etching is then used to remove the deposition layer. The two silicon wafers are aligned and then bonded together face-to-face to complete the microcapillary.

• 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 5575929
• OSTI ID: 870689
• Country of Publication: United States
• Language: English

Related Subjects

method
circular
tubular
channels
silicon
wafers
two-wafer
microcapillary
structure
fabricated
depositing
boron
nitride
bn
separate
crystal-plane
100
110
crystal
orientation
photolithography
photoresist
create
exposed
deposition
plasma
etching
slit
entry
created
path
desired
ultimate
acetone
remove
isotropic
etch
hf
hno
cooh
erodes
trench
layer
channel
half-circular
section
formed
line
wet
aligned
bonded
face-to-face
complete
plasma etching
silicon nitride
boron nitride
silicon wafer
wet etching
silicon wafers
tubular channel
plasma etch
crystal orientation
/216/