International Business Machines Corporation

Leon H Kaplan

Steven M Zimmerman

Richard D Kaplan

Doris P Pulaski

Steven Michael Zimmerman

John Baldwin Lounsbury

Nungavaram S Viswanathan

A laser ablation mask and a method of fabrication therefor. The mask has a pattern of clear areas and scattering areas. The scattering areas are covered with randomly formed facets. The facets act as scattering centers. Areas clear of facets transmit laser energy. Scattering areas refract laser energy. Laser energy directed at the mask, will pass through the clear mask areas to selectively ablate an organic layer placed opposite the mask. However, laser energy is scattered when striking and passing through the scattering areas such that insufficient laser energy passes directly through the mask to reach the organic layer for ablation to occur. The mask is formed by depositing and patterning a metal mask layer on a quartz plate. The patterned mask layer protects intended clear areas. Scattering areas are formed in unprotected plate areas by subjecting the plate to a polymethacrylic acid/bifluoride solution.

Laser ablation mask and method of fabrication

Tantalum (or hafnium) oxide layers, alternated with silicon oxide layers in a dielectric stack reflector type mask for high power laser ablation, are wet etched at a high temperature with a highly caustic solution, preferably potassium hydroxide, to provide a much increased manufacturing yield in comparison with known processes such as ion milling. High feature density is achieved through the use of a resist which is built in two patterning steps. Preferably, a chromium layer is deposited and covered with an organic resist which is patterned by an optical or electron beam exposure. The chromium is then etched by means of the resist mask to form a resist for the caustic wet etch of the tantalum (or hafnium) oxide either separately or together with silicon oxide layers of the dielectric stack reflector mask to be used in the laser ablation process at high power.

Fabrication of laser ablation masks by wet etching

A process for producing a resist pattern by dry development using a resist comprising from 70 to 50% by weight of a novolac resin and from 30 to 50% by weight of a poly(ether pentene sulfone).

Dry-developed, negative working electron resist system

Improved resolution in optical lithography, as used in the very large scale integration of electronic circuits, is obtained by employing a thin film of 4-phenylazo-1-naphthylamine between silicon substrate and overlying layer of light sensitive photoresist. The 4-phenylazo-1-naphthylamine acts as a stable, highly light absorbent medium exhibiting chemical and physical compatibility with the silicon substrate and photoresists with ether-type solvent systems.

Resolution in optical lithography

Exposed patterns in phenol-formaldehyde Novolak resin/diazo ketone resist layers are developed in an oxygen plasma by treating the resist layers, prior to development, with a magnesium salt. This produces a negative pattern. Positive patterns are produced by combining the process with decarboxylation of the exposed areas followed by blanket exposure.

Plasma develoment of resists

A resist composition includes an alkali soluble resin, a light sensitive diazo compound, and a thermally activated free radical initiator. Resist masks are formed from the above composition by providing a layer of resist on a substrate, exposing the layer patternwise to radiation, removing portions of the layer with a developing solution, and heating the remaining portions of the layer at a temperature which activates the initiator and cross-links the resist to improve the physical characteristics of the resist layer and minimize pattern distortion.

Photoresist O-quinone diazide containing composition and resist mask

Method for removing layers of organic material

Carboxylic acids are included in resists to increase their speed and adhesion.

Photoresist process and photosensitive O-quinone diazide article with

Positive photoresist layers including a base soluble resin and a diazo ketone sensitizer are treated with hydrogen ion following initial exposure to achieve changes in the developed resist profile and/or development in a negative mode.

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Yorktown Heights, NY, United States of America

Leon H Kaplan