Tokyo Electron Limited

Kabushiki Kaisha Toshiba

Rie Inazawa, Legal Representative

Eiichi Nishimura

Vaidyanathan Balasubramaniam

Masaaki Hagihara

Hisataka Hayashi

Tokuhisa Ohiwa

Koichiro Inazawa

Kazuto Ogawa

Shuhei Ogawa

Yasunori Hatamura

A method is provided for low-pressure plasma ashing to remove photoresist remnants and etch residues that are formed during preceding plasma etching of dielectric layers. The ashing method uses a two-step plasma process involving an oxygen-containing gas, where low or zero bias is applied to the substrate in the first cleaning step to remove significant amount of photoresist remnants and etch residues from the substrate, in addition to etching and removing detrimental fluoro-carbon residues from the chamber surfaces. An increased bias is applied to the substrate in the second cleaning step to remove the remains of the photoresist and etch residues from the substrate. A chamber pressure less than 20 mTorr is utilized in the second cleaning step. The two-step process reduces the memory effect commonly observed in conventional one-step ashing processes. A method of endpoint detection can be used to monitor the ashing process.

Low-pressure removal of photoresist and etch residue

The present invention is a method of etching a lower layer film () of an organic material formed on a surface layer () of a substrate, using an upper layer film () of an Si-containing organic material as a mask. A mixed gas containing an NHgas and an Ogas is supplied into the processing vessel as an etching gas, so as to perform etching by a plasma of the etching gas. When the etching gas is supplied into the processing vessel, a CD shift value of etching can be controlled by adjusting a flow ratio of Ogas to the NHgas. Specifically, a satisfactory CD shift value can be obtained when the flow ratio is from 0.5 to 20%, and preferably, 5 to 10%.

Etching method

A method is provided for plasma ashing to remove photoresist remnants and etch residues formed during preceding plasma etching of dielectric layers. The ashing method uses a two-step plasma process involving a hydrogen-containing gas, where low or zero bias is applied to the substrate in the first cleaning step to remove significant amount of photoresist remnants and etch residues from the substrate, in addition to etching and removing detrimental fluorocarbon residues from the chamber surfaces. An increased bias is applied to the substrate in the second cleaning step to remove the remains of the photoresist and etch residues from the substrate. A chamber pressure less than 20 mTorr is utilized in the second cleaning step. The two-step process reduces the memory effect commonly observed in conventional one-step ashing processes. A method of endpoint detection can be used to monitor the ashing process.

An etching method etches an organic film by using an inorganic film as a mask at a high etch rate, in a satisfactory etch profile in a satisfactory in-plane uniformity without causing the inorganic film to peel off. An organic film formed on a workpiece is etched by using an inorganic film as a mask with a plasma produced by discharging an etching gas in a processing vessel (). The etching method uses a mixed gas containing NHgas and Ogas for etching the organic film when the organic film is to be etched in a pattern having an opening ratio of 40% or above. The etching method uses NHgas as an etching gas for etching the organic film when the organic film is to be etched in a pattern having an opening ratio below 40%.

Growing community of inventors

Yamanashi-ken, Japan

Rie Inazawa, Legal Representative