Projection photolithography

One of the methods under development at AT T Bell Laboratories for submicron lithography is deep ultraviolet projection photolithography. (O Fine line definition is obtained by use of 248 nm light and a lens of large numerical aperture. Because of the large chromatic aberration of the quartz lens a spectrally line-narrowed krypton fluoride excimer laser is used as a light source. 

When synthesizing simple polymer particles, there are two main approaches used. The first is known as flow projection photolithography and involves passing a polymer solution through microfluidic channels and exposing it to UV light as it flows past [1]. In this format, a photolithographic mask can be placed between the channel and the UV source so that only parts... 

One can distinguish between two different techniques for the production of polymer particles with microsystems (a) emulsification of liquid monomers followed by polymerization of the subsequent monomer droplets and (b) direct polymerization through continuous flow projection photolithography. 

Figure 18.2 Schematic representation of continuous flow projection photolithography. From Ref [21].

C. Y. Chang, S. Y. Yang, M. S. Wu, L. T. Jiang, and L. A. Wang, "A novel method for fabrication of plastic microlens array with aperture stop>s for projection photolithography," Japanese Journal of Applied Physics Part 1-Regular Papers Brief Communications Review Papers, vol. 46, pp. 2932-2935, May 2007. 

M. H. Wu and G. M. Whitesides, "Fabrication of arrays of two-dimensional micropatterns using microspheres as lenses for projection photolithography," Applied Physics Letters, vol. 78, pp. 2273-2275, Apr 2001. 

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