Publication details for Professor Alan PurvisIvey, P.A., McWilliam, R., Maiden, A., Williams, G.L., Purvis, A. & Seed, N.L. (2006). Photolithography on Three Dimensional Substrates. 56th Electronic Components and Technology Conference (ECTC 2006), San Diego, California, IEEE.
- Publication type: Edited works: conference proceedings
- ISSN/ISBN: 0569-5503
- DOI: 10.1109/ECTC.2006.1645660
- View online: Online version
- Durham research online: DRO record
Author(s) from Durham
Photolithography is the primary technique for patterning
planar substrates. However, some higher-density packaging
solutions require fine features to be patterned onto grossly
non-planar substrates, for example, in mechanical, optical and
fluidic microsystems and in novel packaging schemes.
Standard photolithography cannot be used in these cases
because the inevitable gap between the (planar) mask and
(non-planar) substrate causes diffractive line broadening and
loss of resolution. We address this issue by realising the mask
as a Computer Generated Hologram (CGH), which can then
be illuminated to generate an image in space corresponding to
the required non-planar profile. The CGHs are derived from
analytical expressions and encode both amplitude and phase
information. We illustrate the performance with a 100μm line
exposed onto a substrate in the form of a plane/slope/plane, in
which the change in depth is 40mm. Enhancements to the line
shape are discussed that make the technique more robust to
manufacturing process variations. The fact that features in the
range 10-100μm can be imaged at large distance whilst
coping with significant changes of depth indicates that the
technique shows great potential in the microelectronics
IEEE catalog number 06CH377766C.
Conference dates: 30 May-2 June 2006.