Stereochemical control in the ester enolate Claisen rearrangement. 2. Chairlike vs boatlike transition-state selection
摘要:
The preference for chair- and boatlike transition-state geometries in the ester enolate Claisen rearrangement of straight chain, carbocyclic, and heterocyclic propanoates was investigated. A novel stereoelectronic effect in pyranoid and furanoid glycal systems leads to a significant relative stabilization of the boatlike vs the chairlike TS double-ended-dagger. The preferred transition state in six- and five-membered carbocyclic systems is highly dependent on steric factors, as the energy difference between chair- and boatlike TS double-ended-dagger tends to be small. With straight-chain substrates, a significant contribution of the boatlike TS double-ended-dagger to the rearrangement product mixture is only expected in bis-donor substituted allylic esters.
Stereochemical control in the ester enolate Claisen rearrangement. 2. Chairlike vs boatlike transition-state selection
摘要:
The preference for chair- and boatlike transition-state geometries in the ester enolate Claisen rearrangement of straight chain, carbocyclic, and heterocyclic propanoates was investigated. A novel stereoelectronic effect in pyranoid and furanoid glycal systems leads to a significant relative stabilization of the boatlike vs the chairlike TS double-ended-dagger. The preferred transition state in six- and five-membered carbocyclic systems is highly dependent on steric factors, as the energy difference between chair- and boatlike TS double-ended-dagger tends to be small. With straight-chain substrates, a significant contribution of the boatlike TS double-ended-dagger to the rearrangement product mixture is only expected in bis-donor substituted allylic esters.
Novel sulfonyldiazomethanes, photoacid generators, resist compositions, and patterning process
申请人:——
公开号:US20040167322A1
公开(公告)日:2004-08-26
A chemical amplification type resist composition comprising a specific benzenesulfonyldiazomethane containing a long-chain alkoxyl group at the 2-position on benzene ring has many advantages including improved resolution, improved focus latitude, minimized line width variation or shape degradation even on long-term PED, minimized debris left after coating, development and peeling, and improved pattern profile after development and is thus suited for microfabrication.
BASIC COMPOUND, CHEMICALLY AMPLIFIED RESIST COMPOSITION, AND PATTERNING PROCESS
申请人:Hatakeyama Jun
公开号:US20120141938A1
公开(公告)日:2012-06-07
A chemically amplified resist composition comprising a base polymer, an acid generator, and an amine quencher in the form of a β-alanine, γ-aminobutyric acid or 5-aminovaleric acid derivative having an acid labile group-substituted carboxyl group has a high contrast of alkaline dissolution rate before and after exposure and forms a pattern of good profile at a high resolution, minimal roughness and wide focus margin.
ONIUM SALT, CHEMICALLY AMPLIFIED RESIST COMPOSITION, AND PATTERNING PROCESS
申请人:Shin-Etsu Chemical Co., Ltd.
公开号:US20200223796A1
公开(公告)日:2020-07-16
A novel onium salt of formula (1) and a chemically amplified resist composition comprising the same as a PAG are provided. When processed by photolithography using KrF or ArF excimer laser, EB or EUV, the resist composition has a high sensitivity and reduced acid diffusion and is improved in exposure latitude, MEF, and LWR.
Photoacid generators, chemically amplified resist compositions, and patterning process
申请人:Ohsawa Youichi
公开号:US20070292768A1
公开(公告)日:2007-12-20
A photoacid generator has formula (1). A chemically amplified resist composition comprising the photoacid generator has advantages including a high resolution, focus latitude, long-term PED dimensional stability, and a satisfactory pattern profile shape. When the photoacid generator is combined with a resin having acid labile groups other than those of the acetal type, resolution and top loss are improved. The composition is suited for deep UV lithography.
POSITIVE RESIST COMPOSITION AND PATTERNING PROCESS
申请人:NISHI Tsunehiro
公开号:US20100062374A1
公开(公告)日:2010-03-11
A positive resist composition comprises (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) an acid generator. The resin (A) is a polymer comprising recurring units containing a non-leaving hydroxyl group represented by formula (1) wherein R
1
is H, methyl or trifluoromethyl, X is a single bond or methylene, m is 1 or 2, and the hydroxyl group attaches to a secondary carbon atom. The composition is improved in resolution when processed by lithography.