Laser lithography

The microstructure is part of a bottom plate a top plate serves as a cover [21]. Direct-write laser lithography and wet-chemical etching were employed for microfabrication of the bottom plate. Holes were drilled in the top plate to give conduits for the inlet and outlet ports. The top and bottom plates were bonded thermally. 

New Negative Deep-UV Resist for KrF Excimer Laser Lithography... 

A photosensitive composition, consisting of an aromatic azide compound (4,4 -diazidodi-phenyl methane) and a resin matrix (poly (styrene-co-maleic acid half ester)), has been developed and evaluated as a negative deep UV resist for high resolution KrF excimer laser lithography. Solubility of this resist in aqueous alkaline developer decreases upon exposure to KrF excimer laser irradiation. The alkaline developer removes the unexposed areas of this resist. 

KrF excimer laser lithography that utilizes shorter wavelength has become of great interest as a means of fabricating 0.3-0.5 micron patterns in semiconductors (1-3). ... 

Azide-phenolic resin photoresists have been reported by workers at Hitachi. They are used for i-line (12) or for deep UV light (13), and the applications to KrF excimer laser lithography have not been demonstrated. 

In this paper, the material characteristics and lithographic evaluation of this new resist are demonstrated. The resist meets the requirements for KrF excimer laser lithography, which exhibits high sensitivity, high resolution and high aspect ratio pattern profiles. 

A negative deep UV resist, consisting of a photosensitive 4,4 -diazidodiphenyl methane and a poly-(styrene-co-maleic acid half ester) resin, has been found to meet the requirements needed for KrF excimer laser lithography. 

We achieved high aspect ratio sub-half-micron pattern fabrication in 1.0 micron film thickness using this new resist. We are convinced that this new resist could make possible simple and efficient single-layer-resist system for KrF excimer laser lithography. 

It is confirmed that the polymer matrix around ablated area was also affected strongly by laser ablation. The change of the matrix properties are brought about over a few tens of pin. This type of information is basically important and indispensable for practical applications such as excimer laser lithography. The time-resolved fluorescence spectroscopy is one of the powerful characterization methods for ablated polymer matrix. 

Keywords Laser lithography Optical nonlinearities Optical structm-ing Photopolymerization Quantum lithography... 

The field of laser lithography (also often called laser microfabrication) branched out from multiphoton excitation microscopy and has become established during the last decade. The principles of two-photon microscopy, which has enabled high-resolution 3D imaging [3,4] and optical memory [5], were gradually adapted for 3D laser hthography [6]. A relevant collection of seminal papers on the field can be found in [7]. 

Expressions accounting for the nonlinear absorption, which is the main mechanism enabling 3D laser lithography, can be easily obtained by assuming the photomodification to be dependent on the intensity as a... 

Self-focusing is not usually desired for laser lithography and should be avoided by maintaining the power of cw or pulsed laser beam below the self-focusing threshold in the material. Its value depends on the nonhnear part of the refractive index, H2, (n = no + ri2l), as follows [46] ... 

Among the mechanisms of nonlinear absorption, TPA is the most important and widely used for 3D laser lithography in resists and resins. TPA requires smaller incident powers than higher-order processes, for example multipho-... 

Figure 4. (A) Time dependence of AFM (open circle) and magnetic (solid circle) dot size and (B) TEM micrograph of a patterned Co-C film with direct laser lithography.

Poster 16. Sung Kwan Kim, Yang-Soo Kim and Kwangsoo No (Korea Advanced Institute of Science and Technology) The Electronic Structures and Optical Properties of Hf-O-N Thin Films as a Phase Shift Mask for ArF Laser Lithography... 

Chemical amplification type positive resist compositions provided in Table 1 were prepared by Takemoto [4] and were suitable for excimer laser lithography using ArF and KrF lasers. 

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