Surface functionalization & deposition

Close-up deposition tool

Surface functionalization & deposition

In order to develop new, reliable, efficient, and multifunctional micro- and nanocomponents for lab-on-a-chip devices, precise control of the surface properties of the materials is essential. Surface functionalization using various (bio)chemical and physical processes allows for the modification of material properties, without altering their bulk characteristics. Micronit offers solutions for surface activation and finetuning of surface properties. We also provide solutions for localized surface modification, functionalization of closed microchannels, adhesives, and elastomers dispensing. Next to that, Micronit offers spotting of biomolecules, microarrays, and biosensors fabrication. We provide services in anti-stiction, antifouling, and protective coatings along with metallization and electrode definition on polymers, glass, and silicon.

Thin Film Deposition

The deposition of thin layers (coatings) on silicon or glass substrates is conducted through physical, chemical, or laser induced techniques. The thickness of the layers differs from a few nanometers to several micrometers. The most used processes are Physical Vapor Deposition (PVD), Chemical Vapor Deposition (CVD), and Pulsed Laser Deposition (PLD).

 

Physical Vapor Deposition is the general term describing a multitude of methods to deposit thin films on various surfaces. These deposition methods consist of pure physical processes, such as vaporization of the layer forming material in a vacuum or sputtering, whereby the material is atomized through an ion bombardment and transferred into the gaseous phase in order to be deposited. In Chemical Vapor Deposition, a chemical step takes place before the source material is deposited onto the substrate. Pulsed Laser Deposition uses pulses of laser energy to remove material from the surface of a target and deposits the ablated material as a thin film onto the substrate.

 

All of these processes produce pure, high-performance, and strong materials. The choice of technique depends on the type of application the material will be used for. Micronit also offers deposition of metals or dielectric materials.

Technical details

  • Depositions of a few nm to 15 µm

  • Controlled refractive index

  • Adjustable stress

Sputtering and evaporation

  • Cr, Au, Ni, Al, Pt, Pd, Ti, Ta, Cu, SiO2, ITO, CuNi, etc

  • Thickness up to 2000 nm (depending on stress and adhesion)

  • Electroplating > 2 µm

  • Multi layers

  • Annealing (re-crystallization, stress reduction, and diffusion of alloys)

Plasma Deposition – PECVD

  • Thin films of Sio2, Sin, and ONO are most commonly used.

  • Oxide (LF/HF)

  • Nitride (LF/HF)

  • Silicon-oxynitride (adjustable refractive index / tension)

Furnace processes

  • Wet oxidation

  • Dry oxidation

  • Annealing

  • Doping

  • Stoichiometric nitride

  • Stress resistant nitride

  • LPCVD (LTO, PSG, TEOS)

  • LPCVD poly silicon

Automated spotting of reagents

Lab-on-a-chip assays often require one or more reagents to obtain test results. These reagents can be added as a liquid during the assay, but they can also be pre-loaded onto the device in a dried format. This dried format is reconstituted during the assay. Pre-loading of reagents reduces handling steps for the end user and ensures a longer shelf life of the product.

 

Reagents are deposited onto the substrate via spotting. At Micronit, we can deposit picoliter spots with high accuracy, using an in-house automated piezo actuated non-contact dispensing system. This technology is ideal for depositing reagents or spotting microarrays on microscope slides, biosensors, membranes, microfluidic devices, and many other substrates. The reagents can be deposited in your desired array and with a droplet volume of choice on basically any substrate type. Droplets can be spotted individually, on top of each other, or overlapping. Regulation of humidity and temperature allows for the controlled drying of reagents for consistent functional results. Pre-loading of reagents ensures the most economic use of costly reagents and sample volumes and reduces the assay turnaround time.

 

Our experts have experience in spotting various reagents, including proteins (i.e. enzymes, antibodies), nucleic acids (i.e. oligonucleotides), buffers, nanoparticles (i.e. beads), sugars, and surfactants that allow us to support the development, integration, and/or miniaturization of your microfluidic assay.

Spotting specifications for non-contact low volume liquid dispensing

  • Spotting area up to 80x36cm in size

  • Standard droplets of 360-440pl

  • Additional droplet range extension to 100-800pl

  • Exact spot dimensions are dependent on reagent and substrate combination

  • Typically: 400pl - Ø 125/150µm | 10nl – Ø ~350µm

  • Spotting accuracy < 5µm

  • Time to spot 1µl < 30s

  • A cooling unit for reagents and target area

  • Controllable humidity

Customized quality control includes:

  • Target recognition and quality control of the spotted samples

  • Stroboscope camera for visual droplet shape and volume control

Functional areas

The integration of on-chip functional areas in the form of nanocoatings is a capability that is becoming more and more essential as the complexity of devices increases. Specific chemical coating methods offer capabilities for local surface modification. Biocompatible, bioselective, or biorepellent coatings, as well as coatings that cause the local immobilization of molecules, can be deposited. These coatings are used on devices for medical engineering and biotechnology and are applied in genomics, proteomics, drug-delivery analysis, molecular assembly, tissue engineering, biosensor development, nanoscale imaging, etc.

 

According to your wishes and needs, we modify the surface of your chip! The modification can be conducted both locally or on the entire surface.

Why work with us?

At Micronit, we specialize in accompanying our customers all the way from idea to production. Are you looking for a development and manufacturing partner? Take a look at our route to success!

Is your project in need of a solution in the field of deposition, surface functionalization, and activation? Please contact our experts!