Chartered Semiconductor Manufacturing Ltd (corporation)

National Univ. of Singapore

Nanyang Technology Univ.

Yuan-Ping Lee

Lap Chan

Mei Sheng Zhou

Mei-Sheng Zhou

Chee Tee Chua

Jian-Hui Ye

Yong-Feng Lu

A process for curing low-k spin-on dielectric layers based on alkyl silsesquioxane polymers by laser scanning is described wherein curing is achieved by both photothermal and photochemical mechanisms. The layers are deposited by spin deposition, dried and cured by raster scanning with a pulsed laser at energies between 0.1 and 1 Joules/cm.sup.2. Because the laser causes heating of the layer, a nitrogen jet is applied in the wake of the scanning laser beam to rapidly cool the layer and to inhibit oxidation and moisture absorption. The laser induced heating also assists in the discharge of moisture and by-products of the polymerization process. The laser operates at wavelengths between 200 and 400 nm. Insulative layers such as silicon oxide are sufficiently transparent at these so that oxide segments overlying the polymer layer do not inhibit the curing process. Implementation of the laser scanning feature is readily incorporated into an existing spin-on deposition and curing tool.

Laser curing of spin-on dielectric thin films

A method of stripping photoresist and polymer from a wafer after a dry etch of a nitrade or a polysilicon layer that immerses the wafer in a peroxydisulfate (S.sub.2 O.sub.8.sup.2-)/HCl wet bath and while the wafer is still immersed, irradiates the wafer with a UV laser. The method comprises: (a) forming an silicon nitride layer 24 and a photoresist pattern 28 over a semi conductor structure 10; (b) dry etching the silicon nitride layer 24 thus forming a polymer 30 over the photoresist pattern, and the silicon nitride layer, (c) Immersing the substrate, the photoresist pattern, the polymer 30 in a liquid bath 34 comprising (1) peroxydisulfate (S.sub.2 O.sub.8.sup.2-), (2) HCl, and (3) water; and irradiating the photoresist pattern 28 and polymer layer 30 with a UV laser thereby removing the photoresist 28 and polymer 30.

Photoresist and polymer removal by UV laser aqueous oxidant

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Singapore, Singapore

Yuan-Ping Lee