Nonplanar photolithography with computer-generated holograms.
We outline a method for accomplishing photolithography on grossly nonplanar substrates. First we compute an approximation of the diffraction pattern that will produce the desired light-intensity distribution on the substrate to be patterned. This pattern is then digitized and converted into a format suitable for manufacture by a direct-write method. The resultant computer-generated hologram mask is then used in a custom alignment tool to expose the photoresist-coated substrate. The technique has many potential applications in the packaging of microelectronics and microelectromechanical systems.
Maiden
A
A
School of Engineering, University of Durham, Durham DH1 3LE, UK. a.m.maiden@durham.ac.uk
McWilliam
R
R
Purvis
A
A
Johnson
S
S
Williams
G L
GL
Seed
N L
NL
Ivey
P A
PA