Surface patterning is the general term used to describe high-precision fabrication methods that modify substrates.
There is an increasing need for detailed surface structures across a range of scientific disciplines and many ways in which such surface patterns can be produced.
This article explores surface patterning with shadow masks, which has become an important instrument for rapidly fabricating thin film components destined for microelectronics in a repeatable way.
Transparent gold electrodes on a flexible substrate fabricated via shadow masking. Image Credit: Platypus Technologies, LLC
Shadow Masks: Explained
Shadow masks are metal sheets with patterned holes cut out of them. These sheets are then positioned on top of a substrate like silicon, ceramics or glass, or flexible films during metal deposition.
The areas of the substrate that will and will not be coated with metal are determined by the pattern on the shadow mask.
When coupled with e-beam metal deposition, shadow masking is a one-step process for the creation of high-quality patterned sensors, bonding pads, heating wires, electrodes and other features commonly found in microelectronic devices.
Shadow Masks: Advantages
Shadow masks used with e-beam metal deposition utilize metals with very high purity, unlike screen-printing methods, which require organic inks. There are a number of consequential advantages of metal patterns made with shadow masks:
- Low surface roughness (<5 nm)
- Extremely high reproducibility
- High purity metals (>99.999% for Au, Pt along with other metals)
Unwelcome contamination can result from residual organic materials from the inks of screen-printed features. Screen printing can also result in rough surface features and edges, which render the results far less reproducible and less repeatable.
Shadow masking, when compared to photolithography-based methods of surface patterning, does not require expensive photo-activated materials or photomasks, nor expensive processing equipment like spin-coaters, hot plates and solvent benches.
When compared to photolithography, shadow masking is easier to implement and at a lower cost.
Applications with relatively-low resolution (large features >250 µm) are well-suited to shadow masks, whilst photolithography-based methods are recommended for fabricating fine features(1 to 250 µm) with tight tolerances.
Platypus Technologies: Surface Patterning with Shadow Masks
Platypus Technologies offers services in both design and fabrication of shadow masks with custom patterns, sensors, heating lines, metal deposition to create electrodes and other circuit lines.
Platypus Technologies offers a wide range of metal surfaces (Ag, Pt, W, Cr, Ni Au, Ag, Al, Ti) and substrates (ceramic, glass, flexible films, silicon, ceramic) to suit even the most complex projects and to produce custom coatings.
Platypus Technologies’ dicing and cutting services also singulate devices for plug-and-play applications. Contact Platypus Technologies today to find out more.
This information has been sourced, reviewed and adapted from materials provided by Platypus Technologies, LLC.
For more information on this source, please visit Platypus Technologies, LLC.