Glass Microfluidic Chip Customization and Processing

Glass has superior optical properties, hydrophilic properties, and stable properties, so it has become one of the most widely used microfluidic chip materials.

In the field of the chemical industry, a large number of acids, bases, and organic reagents are often used. Glass, as an excellent chemical and corrosion-resistant material, is bound to become the first choice of microfluidic chip substrate in organic experiments where acids and bases are needed. It is possible to obtain good results from a variety of biochemical experiments using microfluidic chips.

Chip Etching

The commonly used method of fabricating glass-based microfluidic chips is standard lithography combined with wet etching. The mask with a pattern structure is covered on the glass pre-coated with a thin photoglue layer and a sacrificial layer (uniform chromium plate). Then, under the irradiation of parallel ultraviolet light of a certain intensity, the pattern on the mask is transferred to the uniform chromium plate. After that, the desired microstructure can be created on the uniform chromium plate by developing, fixing and wet etching. The uniform chromium plate with microstructure is then bonded with a glass cover to produce a complete chip.

Chip Bonding

There are many ways to bond glass-based microfluidic chips. Although some researchers have tried simple reversible bonding methods such as epoxy resin bonding method and film bonding method, the effect is not ideal, so the application range of irreversible high-temperature bonding method is wider. Alfa Chemistry uses high temperature bonding to bond glass-based chips. The high-temperature bonding method refers to bonding two clean glass sheets to be bonded together, and then transferring them to a muffle furnace, and raising the temperature above the annealing temperature of the glass by heating and pressing. The bonding process of the entire chip is completed through temperature control stages such as annealing and cooling.

Glass Chip Material

• Optical Glass

B270 glass is a kind of colorless, high-transmittance glass melted from superior-purity raw materials, which is easy to process. It has a high transmittance and hardness from ultraviolet to infrared wavelengths. It is one of the most effective optical glass materials. With excellent chemical resistance and optical properties, it is often used in scientific instruments, glasses, and microscopes.

• Quartz Glass

Quartz glass has a low thermal expansion coefficient, strong chemical resistance, high temperature resistance (up to 900^oC), excellent optical properties, such as uniformity and high ultraviolet transmittance. It is suitable for microfluidic chips for microfluidic flow cells, microreactors and ultraviolet spectrophotometry. Quartz glass is also more resistant to thermal shock than other types of glass.

• Borosilicate Glass

D263 and Borofloat 33, provide an extremely durable and flexible material that can resist extreme temperatures as well as many strong chemicals, including acids, saline solutions, chlorine, oxidizing, and corrosive chemicals. Common applications include high-precision lenses, laboratory equipment, and pharmaceutical containers.

Alfa Chemistry

Glass chip has good chemical properties, easy lithography and etching, various bonding processes, excellent light transmittance, and can also be reused. Alfa Chemistry can provide chips with different depths and widths of channels according to customer requirements.

References

• Toan, N.V.; et al. Glass Patterning: Technologies and Applications. 2018.
• Ku, X.; et al. Low-cost rapid prototyping of glass microfluidic devices using a micromilling technique[J]. Microfluidics & Nanofluidics. 2018, 22(8):82.

Our products and services are for research use only.