Photolithographic Service
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Combining advanced lithography concepts with advanced fabricating instruments, Creative Biolabs provides our clients with the most robust and stable solutions for lithography demands of different sizes and precisions. Our processing capabilities cover wafers from 1 to 12 inches, and achieve stable manufacturing accuracy at the micron level.
Photolithographic
Photolithography is a precision machining approach inherited from the microelectronics and semiconductor industries. Photolithography in the strict sense refers to the process of transferring the channel design created on a photomask to a sacrificial photoresist film. Lithography can precisely control the shape of the pattern and obtain sub-micron fabricate accuracy. Here at Creative Biolabs, we are capable of printing the preset device outline on the photoresist with the highest precision and stability. Our workflow will include the upstream and downstream processing procedures of photolithography, you may select your exiting point and processing procedure freely.
Fig 1. Complete workflow of photolithography. (Creative Biolabs)
Photomask Construction
The construction of the photomask is the first step in microfluidic fabrication. Photomask networks designed with industrial graphics software are printed onto special films. Patterned chromium is deposited onto the quartz plate for transferring the channel design to other substrates. The geometric accuracy of micro-fabrication objects is obviously not better than that of photomasks, and our micron-scale pattern deposition technology will be the best choice for you to build functional microfluidic chips.
Substrate Pretreatment and Photoresist Coating
In order to improve the adsorption capacity of the substrate to the photoresist, the surface of the substrate will be thoroughly dehydrated and modified. A photoresist that is sensitive to UV radiation with resist properties is then smeared on one side of the substrate. The spin-coating craft and empirical parameters allow Creative Biolabs to apply the photoresist to the maximum uniformity and flatness on the substrate surface and form a sub-micron adhesion layer.
Soft Baking
The photoresist film formed after spin coating still has 10-30% solvent content, which can be reduced to about 5% by high-temperature baking. This step avoids the contamination of the photoresist film by particles in the environment, and also reduces the uneven stress caused by centrifugal force during the spin coating.
Exposure
The pre-processed photomask and the substrate covered with photoresist film are placed under a uniform UV beam, and selectively irradiated with a specific wavelength. The photosensitive agent in the photoresist composition will undergo a photochemical reaction, so that the chemical properties of the photosensitive areas of the positive resist or non-photosensitive areas of the negative resist are modified locally, making them soluble in the developer solution. In this way, the pattern on the mask will be completely transferred to the substrate.
Development
After the exposure, the substrate covered with photoresist film will be immersed in a developing solution. The resist polymer in specific areas will be broken down and melted in the developing solution, and then removed from the substrate.
Hard Bake
After the development is completed, the photoresist pattern has been basically determined. High-temperature treatment can remove the remaining solvent in the photoresist, make it more stable, improve the etching resistance and enhance the adhesion of the photoresist to the base material. In addition, the photoresist at high temperatures will soften temporarily, thereby correcting micro-defects generated during processing.
Etching
Etching is a commonly used technology to obtain the desired channel depth and structure along the photoresist pattern on the substrate. According to the precision demands or topology requirements, Creative Biolabs provides the most suitable etching procedure.
Photoresist Removal and Sealing
If you no longer need photoresist as a protective layer, but expect to directly use glass or silicon plates as the substrate of microfluidic chips, we provide thorough photoresist removal and channel sealing services. Hydrophilic/hydrophobic modification of channel surfaces or surface conjugation services for biological reagents is also available.
Fig 2. Schematic of photolithography protocol. (Creative Biolabs)
Our Services
Precise microfabrication platforms and ultra-clean laboratory configurations allow Creative Biolabs to perform cutting-edge technologies such as electron beam lithography, contact lithography and stepper lithography. Combining a variety of lithography concepts with abundant manufacturing experience, we provide our clients with photolithographic services for high-precision standard chips or customized chips. You may design the microfluidic chip according to your own needs, or directly entrust us with designing and fabricating.
Please don't hesitate to contact us for any needs.
For Research Use Only. Not For Clinical Use.
