Etching glass channels for microfluidics

Introduction

This article describes the process of preparing microfluidic channels etched in glass. The channels are formed by HF based wet etch of borosilicate glass (Pyrex or Borofloat). As such the channels will have semi-circular shaped sidewalls.

Associated documents and references

Equipment needed

Process run card

Step

Clean

Machine

Wbgen-nonhf

Process

10min in Nanostrip @ 90°C

Comments
  • use pyrex dish
  • Rinse and dry in verteq

Disposal of nanostrip: wait for solution to cool down and dump it into a bath of running water. Rinse your dish under DIW.

Done date

 

 

 

Step

aSi growth

Machine

LPCVD Tylan

Process
  • aSi525 – 2h30
  • target: 150nm

 

Comments

Use polysilicon boat

Done date

 

 

 

Step

Measure aSi thickness

Machine

SOPRA Ellipsometer:

Process

aSi on glass @ 57° 

 Wafer ID

aSi thickness (nm)

 

 

 

 

 

 

 

 

Comments

 

Done date

 

 

 

Step

Photolithography

Machine

EVG620 – SiteCoat– Yes Oven

Process
  • Yes Oven: prime for 5min (program #1) (optional)
  • Sitecoate: 6C14NEBR
  • EVG aligner: Expose 1 scan @ 90 mJ/cm2.
  • SiteCoat: D1813_45.LN 45s dev + 90s HB @ 90°C

Comments

 

Done date

 

 

 

Step

Etch aSi

Machine

AMAT P5000

Process
  • NANOTOOLS POLY ETCH: 40s

Comments

 

Done date

 

 

 

Step

Glass Etch

Machine

Acid HF bench

Process
  • 10:1 HF49%:HCl @ RT.
  • Let rest for 5min prior to etch
  • average etch rate: 5um/min.
  • Photoresist strip wbsolvent : 10min ACE + IPA + DIW.
  • Strip aSi in TMAH bench @ 85°C

Comments

 

Done date

 

 

 

 

Step

inspection

Machine
  • Microscope and haze lamp
  • Measure depth of cavities

Process

Inspec all wafers for defects and remaining silicon. Redo TMAH in case of remaining aSi.

Comments

 Wafer ID

Cavity Depth in µm

 

 

 

 

 

 

 

 

 

Done date