(Hybrid) bonding

Two hermetic seal-bonded chips

Hybrid bonding

As microfluidic devices gain in on-chip complexity, bonding has become a challenging process for device manufacturers. Especially for systems used in biological, pharmaceutical, or medical applications, new methods have been developed to leave the sensitive biological material undamaged during the bonding process.

 

Micronit is experienced in the bonding of polymer, glass, silicon, and hybrid devices and can offer customer-specific bonding solutions when needed. We provide solutions for the integration of porous membranes, flexible films, sensors, and biosensors as well as for assembly, sealing, packaging, and labeling of lab-on-a-chip devices.

Temperature-dependent bonding technologies

Temperature is an important factor in determining which bonding process to use. Bonding at low temperatures is necessary when dealing with devices that contain temperature-sensitive elements, like certain coatings, polymers, or biological materials. Hermetically sealed bond interfaces can be achieved at room temperature with a laser-assisted process.

 

In a product development process, we will always discuss the specific bonding requirements of the product with our customers. Overseeing the entire manufacturing process and considering costs and scalability, the right choices in materials and processes can be made.

Wafer bonding

There are different wafer bonding techniques, such as

  • Direct/fusion bonding

  • Anodic bonding

  • Eutectic bonding

  • Adhesive bonding

  • Laser-assisted room temperature bonding

Direct/fusion bonding

Fusion or direct bonding is a technique that joins two or more wafers of the same material together. Fusion bonding is conducted at high temperatures, which makes the bond as strong as the mechanical strength of the base material. However, direct bonding at lower temperatures is also feasible.

Anodic bonding

Anodic bonding is a technique that allows two or more wafers of different materials (e.g. silicon and glass) to be bonded. The process of anodic bonding is usually done at 400°C, which is a lower temperature than used for direct bonding. The lower temperature reduces the tension in glass and silicon layers and keeps the biological/chemical characteristics of any integrated elements intact.

Eutectic bonding

Eutectic bonding is based on the ability of silicon or glass to form a eutectic alloy with certain metals. Through the application of pressure and heightened temperatures, a material bound connection is forged between two wafers, connected by a thin metal layer. An established eutectic alloy is gold-silicon.

Adhesive bonding

In adhesive bonding, substrates of different types of materials are connected by an intermediate layer. The intermediate adhesive layer can be a type of glue, or for instance, a photo-patternable dry film resist/adhesive. Bonding temperatures depend on the material of the bonding partners and on the type of intermediate layer.

Laser-assisted room temperature bonding

Micronit has developed this patented bonding process that can generate hermetic bonds, while only locally applying heat. Substrates can be of glass or silicon, or a hybrid combination of both. In this technique, first, a prebond is made using a metal interlayer. After this, the formed prebond is fortified by laser processing. Because the use in high temperatures is avoided, temperature-sensitive components, like biomaterials or liquids, can be part of the bonded stack.

 

Micronit offers a broad range of bonding capabilities so that requirements for hybrid integration and specific applications or materials can be met.

 

Are you looking for some more detailed info on our bonding capabilities? We have an application note on this topic.

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 bonding solution? Please contact our experts!