Microfluidics – Services for Design, Manufacturing, Instrumentation

Sandwich Structures for Microfluidic Manifolds

GeSiM offers different approaches for micromachining of 3D structures. Microfluidic devices are easily made from silicon/glass sandwiches. However, many applications require optical transparent channel structures. Glass/glass sandwiches are precise but more expensive and give high accuracy.

PDMS microfluidics keeps prices close to disposables but requires more initial instrumentation. Please refer to the GeSiM MicCell or even the Micro-Contact-Printers. The latter one prints your microfluidic devices (NIL – Nano-Imprint-Lithography) including sample handling by onboard pipettors.

Different sandwich methods for microfluidic devices

3D Microfluidics from Hard Materials

• Anisotropic wet-chemical etching of Si with KOH: inexpensive batch process, smooth surface, side wall angle depends on crystal orientation
• Anisotropic plasma-enhanced dry Si etching (ASE/Bosch process): single wafers, dense structures, vertical side walls
• Super-rough surfaces by etching in SF₆/C₄F₈ plasma
• Isotropic wet etching of glass with HF: round channels, 3 – 700 µm deep
• Ultrasonic drilling and micro-blasting for 150 – 1000 µm thick glass, Si, quartz

Etched channel structure of a micromachined sieve

KOH etched sieve structure

Micro pores, realized by ASE at presence of insulated platinum electrodes

GeSiM dispenser structure: View from the pump chamber of the fluid inlet

Photoemulsion Masks with your Design

We supply cost effective photo emulsion masks for patterns down to 25 microns. Smaller features are available with chrome masks from an external source. The photo emulsion masks are based on glass substrates 5″ x 5″ as well as on films of diverse sizes.

If desired we also offer CAD services for your particular application.

Design Guidelines – Technical Information on the GeSiM Mask Service

We accept CAD data accordingly to the following rules, as well as create plot files based on your specs.

Supported data formats

• AutoCAD™ DXF up to release 12 (preferred),
• Gerber RS 274X,
• GDS-II, CIF.

Lithography equipment (Left), photoemulsion mask (Right)

Design guidelines

For 5” masks, the plotting area is restricted to 100 mm x 100 mm. For a centered image on the mask, the outer dimensions of the drawing must be exactly 100 mm x 100 mm. Placing of four small squares (e.g. 50 microns x 50 microns) in the corners of the layout supports this contraint.

In DXF files, please use only solids, circles and closed polylines with a width of zero. These patterns will be filled by our software. Do not try to fill them with the hatch command. Avoid “islands”, try to split complex figures in separate parts instead. For text information, use only the text command, never dtext or mtext. Please set the font to txt.shx.

Download our sample file as a design template.

Thin Film Services – Coating Technologies

GeSiM offers the deposition of conducting and insulating films by

• Physical Vapor Deposition
• Plasma-Enhanced Chemical Vapor Deposition
• Screen Printing

PVD and PECVD applies to all kind of substrates up to 4 inch diameter.

Screen Printing

• Dispensing of the state of the art adhesives on printed circuit boards and micro system substrates for surface mounted device packaging.
• Dispensing of silicon rubber.
• Includes sieve design and production.
• Typical thickness of printed materials in the range of 15 to 35 Microns.

Bonding – Connecting Microfluidic Chips with and without Glue

In order to achieve closed fludic channels MEMS technologies offers different – material dependent – methods. The GeSiM engineering service covers:

• Anodic bonding
• Silicon fusion bonding
• Die bonding using adhesives
• Wire bonding