Two-step stripping method for removing via photoresist during the fabrication of partial-via dual damascene features
OwnerChih-Ning Wu, Wen-Liang Lien +2inventors
InventorsChih-Ning Wu, Wen-Liang Lien, Charlie Lee, Meiling Li
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Abstract
A two-step stripping method for removing via photoresist during the fabrication of trench-first partial-via dual damascene features is disclosed. In the first cleaning step, inert gas (He, Ar, N2)/fluorocarbon plasma is used to contact the remaining “Via Photo” for a short time period not exceeding 20 seconds. Thereafter, in the second cleaning step, a reducing plasma is used to completely strip the remaining “Via Photo”, thereby preventing the low-k or ultra low-k carbon-containing dielectric layer from potential carbon depletion.
Claims17
A two-step stripping method for removing via photoresist during the fabrication of trench-first partial-via dual damascene features, comprising:
- preparing a semiconductor substrate provided thereon with a dielectric layer, a hard mask layer over the dielectric layer, and a first bottom anti-reflection coating (BARC) layer over the hard mask layer, wherein the hard mask layer comprises a metal layer;
- forming, on the first BARC layer, a pattern of a trench photoresist layer comprising a trench opening exposing a portion of the subjacent first BARC layer;
- etching the exposed first BARC layer and the underlying hard mask layer through the trench opening to form a trench recess in the hard mask layer;
- stripping the trench photoresist layer and the first BARC layer;
- depositing a second BARC layer over the hard mask layer and filling the trench recess thereof;
- forming, on the second BARC layer, a pattern of a via photoresist layer comprising a via opening, which is located above the trench recess, thereby exposing a portion of the subjacent second BARC layer;
- etching the exposed second BARC layer, the underlying hard mask layer and the dielectric layer through the via opening to form a via recess in an upper portion of the dielectric layer;
- and
- stripping the via photoresist layer using a two-step cleaning process comprising a first cleaning step:
- contacting the via photoresist layer with hydrogen-free fluorocarbon plasma in a short period of time not exceeding 20 seconds, and thereafter, proceeding a second cleaning step:
- completely removing the via photoresist layer by using reducing plasma.
A partial-via dual damascene process, comprising:
- preparing a semiconductor substrate provided thereon with a dielectric layer, a hard mask layer over the dielectric layer, and a first bottom anti-reflection coating (BARC) layer over the hard mask layer, wherein the hard mask layer comprises a metal layer;
- forming, on the first BARC layer, a pattern of a first photoresist layer comprising a trench opening exposing a portion of the subjacent first BARC layer;
- etching the exposed first BARC layer and the underlying hard mask layer through the trench opening to form a trench recess in the hard mask layer;
- stripping the first photoresist layer and the first BARC layer;
- depositing a second BARC layer over the hard mask layer and filling the trench recess thereof;
- forming, on the second BARC layer, a pattern of a second photoresist layer comprising a via opening, which is located above the trench recess, thereby exposing a portion of the subjacent second BARC layer;
- etching the exposed second BARC layer, the underlying hard mask layer and the dielectric layer through the via opening to form a via recess in an upper portion of the dielectric layer;
- contacting the second photoresist layer with CF4 plasma for a time period not exceeding 20 seconds for removing metallic residues on surface of the second photoresist layer and preventing the dielectric layer from carbon depletion;
- stripping the second photoresist layer by using reducing plasma;
- and
- performing a dry etching to etch the dielectric through the via recess.
Dependencies are inferred from the claim text.