Resources Contact Us Home
Laser spectral engineering for lithographic process

Image Number 16 for United States Patent #6671294.

An integrated circuit lithography technique called spectral engineering by Applicants, for bandwidth control of an electric discharge laser. In a preferred process, a computer model is used to model lithographic parameters to determine a desired laser spectrum needed to produce a desired lithographic result. A fast responding tuning mechanism is then used to adjust center wavelength of laser pulses in a burst of pulses to achieve an integrated spectrum for the burst of pulses approximating the desired laser spectrum. The laser beam bandwidth is controlled to produce an effective beam spectrum having at least two spectral peaks in order to produce improved pattern resolution in photo resist film. Line narrowing equipment is provided having at least one piezoelectric drive and a fast bandwidth detection control system having a time response of less than about 2.0 millisecond. In a preferred embodiment, a wavelength tuning mirror is dithered at dither rates of more than 500 dithers per second in phase with the repetition rate of the laser. In one case, the piezoelectric drive was driven with a square wave signal and in a second case it was driven with a sine wave signal. In another embodiment, the maximum displacement was matched on a one-to-one basis with the laser pulses in order to produce a desired average spectrum with two peaks for a series of laser pulses. Other preferred embodiments utilize three separate wavelength tuning positions producing a spectrum with three separate peaks.

  Recently Added Patents
Automatic logical position adjustment of multiple screens
Account and customer creation in an on-line banking model
Campanula plant named `PKMM03`
Methods and apparatus for voltage selection for a MOSFET switch device
Rose plant named `ESM R044`
Method and apparatus for decoding/encoding a video signal with inter-view reference picture list construction
Secure data exchange for processing requests
  Randomly Featured Patents
Flexible adapter for use between LGA device and printed circuit board
Superconducting multilayer architecture for radiative transient discrimination
Edible baked article
Clock translator and parallel to serial converter
Multipurpose interface for an automated meter reading device
Clothed doll
Low profile, high stretch knit prosthetic device
Portable strobe light
Data input device of semiconductor memory device
Catalyst composition for copolymerizing ethylene