Nxp B.v.

Koninklijke Philips Corporation N.v.

Peter Zandbergen

David Van Steenwinckel

Jeroen Herman Lammers

Peter Dirksen

Johannes Van Wingerden

Yuri Aksenov

Anja Vanleenhove

Laurent Marinier

Hans Kwinten

Robert Duncan Morton

The invention relates to a method of photolithography comprising the steps of: providing a substrate and forming a layer of a photoresist on the substrate, performing a first exposure in which a predetermined part of the layer of photoresist is irradiated through a mask having a pattern for forming a latent image of said pattern in the layer of the photoresist, performing a pretreatment on the layer of the photoresist to remove a predetermined part of the latent image before performing the fixation. The method provides an improved process window. The invention further relates to a photoresist for use within the method of the invention.

Photolithography

A method of irradiating to pattern a photosensitive layer such as a resist (L) immersed in a fluid (L), involves applying a removable transparent layer (L, L), projecting the radiation onto the resist through the immersion fluid and through the transparent layer, such that imperfections in the fluid are out of focus as projected on the surface, and subsequently removing the transparent layer. The transparent layer can help distance such imperfections from the focus of the radiation on the surface and so can reduce or eliminate shadowing. Hence the irradiation can be more complete, and defects reduced. It can be particularly effective for imperfections in the form of small bubbles or particles in the immersion fluid especially at the fluid/surface interface for example. The radiation can be for any purpose including inspection, processing, patterning and so on. The removal of the transparent layer can be combined with a step of developing the resist layer.

Removable pellicle for immersion lithography

The present invention provides a method of lithographic patterning. The method comprises: applying to a surface to be patterned a photoresist () comprising a polymer resin, a photocatalyst generator which generates a catalyst on exposure to actinic radiation, and a quencher; exposing the photoresist () to actinic radiation through a mask pattern (); carrying out a post-exposure bake; and then developing the photoresist () with a developer to remove a portion of the photoresist which has been rendered soluble in the developer. Either the polymer resin is substantially insoluble in the developer prior to exposure to actinic radiation and rendered soluble in the developer by the action of the catalyst, and by the action of the quencher during the bake, or the polymer resin is soluble in the developer prior to exposure to actinic radiation and rendered substantially insoluble in the developer by the action of the catalyst, and by the action of the quencher during the bake.

Lithographic method

The present invention provides a method of lithographic patterning in order to the strength of the patterned photoresist. The method comprises: applying to a surface to be patterned a photoresist () comprising a polymer resin, a photocatalyst generator which generates a catalyst on exposure to actinic radiation, and a quencher; and exposing the photoresist () to actinic radiation through a mask pattern (). This is followed, in either order, by carrying out a post-exposure bake; and developing the photoresist () with a developer to remove a portion of the photoresist which has been exposed to the actinic radiation. The polymer resin is substantially insoluble in the developer prior to exposure to actinic radiation and rendered soluble in the developer by the action of the catalyst, and wherein the polymer resin is crosslinked by the action of the quencher during the bake.

A method of achieving frequency doubled lithographic patterning is described. An optical pattern () having a first period (p) is used to expose conventional acid-catalysed photoresist () on substrate (), leaving regions of high exposure (), regions of low exposure () and intermediate regions (). Processing proceeds leaving regions () which received high exposure very polar, i.e. hydrophilic, regions () of low exposure very apolar, i.e. hydrophobic, and the intermediate regions having intermediate polarity. A developer of intermediate polarity such as propylene glycol methyl ether acetate is then used to dissolve only the intermediate regions () leaving photoresist patterned to have a pitch (p) half that of the optical period (p). Alternatively, the photoresist is removed from the apolar and polar regions leaving only the intermediate regions () again with the same pitch (p) half that of the optical period (p).

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Hechtel-Eksel, Belgium

Peter Zandbergen