A polymer compound containing a repeating unit shown by the formula (1c) and one or more repeating units selected from a repeating unit shown by the formula (2) and a repeating unit shown by the formula (3), ##STR00001##
wherein M.sub.b.sup.+ represents a sulfonium cation shown by the formula (a) or an iodonium cation shown by the formula (b), ##STR00002## This polymer compound is suitable as a base resin of a resist composition capable of forming a resist film that allows pattern formation with extremely high resolution, small LER, and excellent rectangularity.

A resist composition comprising a base polymer and a metal salt of carboxylic acid or sulfonamide is provided, the metal being selected from calcium, strontium, barium, cerium, aluminum, indium, gallium, thallium scandium, and yttrium. The resist composition exhibits a sensitizing effect and an acid diffusion suppressing effect and forms a pattern having improved resolution, LWR and CDU.

A resist composition comprising a base polymer and a metal salt of an iodinated aromatic group-containing carboxylic acid, the metal being selected from among sodium, magnesium, potassium, calcium, rubidium, strontium, cesium, barium, cobalt, nickel, copper, zinc, cadmium, tin, antimony, zirconium, hafnium, cerium, aluminum, and indium, exhibits a sensitizing effect and an acid diffusion suppressing effect and forms a pattern having improved resolution, LWR and CDU.

A resist composition comprising a 2,5,8,9-teraaza-1-phosphabicyclo[3.3.3]undocane, biguanide or phosphazene salt of an iodinated aromatic group-containing carboxylic acid exhibits a sensitizing effect and an acid diffusion suppressing effect and forms a pattern having improved resolution, LWR and CDU.

A resist composition comprising a base polymer and a 2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane salt compound offers a high dissolution contrast, minimal LWR, and dimensional stability on PPD.

A positive resist composition comprising a polymer adapted to be decomposed under the action of acid to increase its solubility in alkaline developer and a sulfonium compound of specific structure has a high resolution. When the resist composition is processed by lithography, a pattern with minimal LER can be formed.

Various vinyl addition polymers of nadic anhydride are disclosed. Examples of such polymers include copolymers and terpolymers of nadic anhydride with a wide variety of norbornene-type monomers. The nadic anhydride polymers are found to be useful in forming a wide variety of photosensitive compositions, both positive and negative, which are capable of forming high resolution imageable films exhibiting excellent dielectric properties (low-k) and thermal properties, and thus are useful in the fabrication of a variety of microelectronic and optoelectronic devices, among others.

A pattern forming method including a step of coating a substrate with an actinic ray-sensitive or radiation-sensitive resin composition and forming an actinic ray-sensitive or radiation-sensitive film; a step of simultaneously irradiating the actinic ray-sensitive or radiation-sensitive film with a plurality of electron beams; and a step of developing the actinic ray-sensitive or radiation-sensitive film after the irradiation with electron beams is provided. The composition contains a resin (A), a photoacid generator (B), and an acid diffusion control agent (C) and a molar ratio (Qp) between the photoacid generator (B) and the acid diffusion control agent (C), which is represented by Equation (1) is 0.3 or greater.

Qp(molar ratio)=Acid diffusion control agent (C)/Photoacid generator (B) (1)

A radiation-sensitive composition contains a polymer having an acid-releasable group, and a compound (Q) represented by formula (1). In the formula (1), L.sup.1 represents an ester group, CONR.sup.3, a (thio)ether group, or a sulfonyl group. R.sup.4 represents a hydrogen atom, a substituted or unsubstituted C1 to C20 monovalent hydrocarbon group, a halogen atom, a hydroxy group, or a nitro group. R.sup.5 represents a C1 to C20 monovalent hydrocarbon group, a C1 to C20 monovalent halogenated hydrocarbon group, or a halogen atom, and optionally two R.sup.5s taken together represent an alicyclic structure together with the carbon atom(s) between the two R.sup.5s. L.sup.2 represents a single bond or a divalent linking group.

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Disclosed in the present invention are a bottom anti-reflective coating for deep ultraviolet lithography, a preparation method therefor and the use thereof. A polymer disclosed in the present invention is prepared by the following method: (1) preheating a solvent I; (2) mixing a monomer as shown in formula (A), a monomer as shown in formula (B), a monomer as shown in formula (C), a cross-linking agent as shown in formula (L), and an initiator and a solvent II to obtain a mixed solution; and (3) adding the mixed solution to a preheated solvent and perform a polymerization reaction, wherein step (1) and step (2) are in no particular order. The bottom anti-reflective coating for deep ultraviolet lithography can reduce the reflectivity, and after the bottom anti-reflective coating is spin-coated with a photoresist, no scum formed by the bottom anti-reflective coating is observed.

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