A photoresist layer is coated over a wafer. The photoresist layer includes a metal-containing material. An extreme ultraviolet (EUV) lithography process is performed to the photoresist layer to form a patterned photoresist. The wafer is cleaned with a cleaning fluid to remove the metal-containing material. The cleaning fluid includes a solvent having Hansen solubility parameters of delta D in a range between 13 and 25, delta P in a range between 3 and 25, and delta H in a range between 4 and 30. The solvent contains an acid with an acid dissociation constant less than 4 or a base with an acid dissociation constant greater than 9.

Disclosed are a resin containing a structural unit represented by formula (I), a structural unit represented by formula (a1-1), a structural unit represented by formula (a1-2) and a structural unit represented by formula (a2-A), and a resist composition including the same: ##STR00001##

A curable composition and a permanent resist film made using this curable composition are provided. The composition dissolves well in solvents, gives coatings superior in alkali developability, thermal decomposition resistance, light sensitivity, and resolution, and is particularly suitable for the formation of permanent resist films. Specifically, the composition is a curable composition for permanent resist films and contains a phenolic hydroxyl-containing compound (A) that has a molecular structure represented by structural formula (1):

##STR00001##

(where R.sup.1 is hydrogen, alkyl, or aryl, and n is an integer of 2 to 10; R.sup.2 is alkyl, alkoxy, aryl, aralkyl, or halogen, and m is an integer of 0 to 4; if m is 2 or more, the plurality of R.sup.2s may be the same or different from one another, and may be bonded to either of the two aromatic rings in the naphthylene structure) and a photosensitizer (B1) or curing agent (B2).

A resist composition comprising a base polymer and a sulfonium salt of iodized benzoic acid offers a high sensitivity and minimal LWR independent of whether it is of positive or negative tone.

A method of forming a pattern, the method including exposing under KrF excimer laser beams, a chemical for photolithography coated through spin coating, including a resin ingredient having a mass-average molecular weight (Mw) of 2000 to 50000 and an organic solvent having a saturated vapor pressure of 1 kPa or more (1 atm, 20° C.) and a viscosity of 1.1 cP (1 atm, 20° C.) or less.

A resist underlayer film-forming composition for lithography including a copolymer having a structural unit of the following Formula (1) to Formula (3), a crosslinking agent, an organic acid catalyst, and a solvent: ##STR00001##
(wherein R.sup.1s are independently a hydrogen atom or a methyl group, R.sup.2 is a C.sub.1-3 alkylene group, A is a protective group, R.sup.3 is an organic group having a 4-membered ring to 7-membered ring lactone framework, adamantane framework, tricyclodecane framework or norbornane framework, R.sup.4 is a linear, branched or cyclic organic group having a carbon atom number of 1 to 12 in which at least one hydrogen atom is substituted with a fluoro group and which optionally has at least one hydroxy group as a substituent).

Provided is a method of fabricating a micro-nano structure, including: forming a reflective layer and a fluid polymer layer sequentially on a surface of a substrate; pressurizing the substrate and a mask having a micro-nano pattern to attach to each other, squeezing the fluid polymer layer into a light-transmission area of the mask, and curing the fluid polymer layer; and exposing, wherein a fluid polymer in the light-transmission area is configured to sense light under a combined effect of a transmitted light and a light reflected by the reflective layer, such that a micro-nano structure is obtained. The method solves the problem of limited diffraction, improves the processing resolution by reducing the transmission loss of evanescent waves through reflective light field enhancement, and reduces the difficulty and cost of mask processing and pattern defects by using shallow pressurizing in combination with exposure.

A polymer comprising recurring units derived from vinylanthraquinone, recurring units derived from acid labile group-substituted hydroxystyrene, and recurring units derived from hydroxystyrene is provided. The polymer is used as a base resin to formulate a positive resist composition having a high resolution and minimal LER.

Embodiments of a photomask removal apparatus for removing photoresist off of a photomask are provided herein. In some embodiments, a nozzle head for removing photoresist off of a photomask includes: a nozzle portion having a first side and an opposing second side and a flow path extending from the first side to the second side, wherein the flow path includes an orifice disposed between the first side and the second side and a nozzle that extends from the orifice to a nozzle exit on the second side, and wherein the flow path in the nozzle increases in width at an angle from the orifice to the second side; and a vacuum portion coupled to the nozzle portion, wherein the vacuum portion includes a first side and an opposing second side that faces the nozzle exit, wherein the vacuum portion includes a vacuum port extending from the second side.

An underlayer is formed to cover the upper surface of a substrate and a guide pattern is formed on the underlayer. A DSA film constituted by two types of polymers is formed in a region on the underlayer where the guide pattern is not formed. Thermal processing is performed while a solvent is supplied to the DSA film on the substrate. Thus, a microphase separation of the DSA film occurs. As a result, patterns made of the one polymer and patterns made of another polymer are formed. Exposure processing and development processing are performed in this order on the DSA film after the microphase separation such that the patterns made of another polymer are removed.