Dry etching method
First Claim
1. A dry etching method of processing a polycide layer, comprising the steps of:
- forming a polycide layer on an oxide layer, the polycide layer being comprised of a first polysilicon layer and a refractory metal silicide layer in this order;
forming a patterned resist on said polycide layer;
providing an undercut in said refractory metal silicide layer which contacts the patterned resist by a first isotopical dry etching; and
performing an anisotropic dry etching of said polycide layer using said patterned resist as a mask wherein a gas used in said anisotropic dry etching includes Br.
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Abstract
An object of this invention is to provide a dry etching method enabling a higher productivity and a higher yield without giving any bad effect to a substrate (such as, for instance, damages to a gate oxide film bed) even in a case where a side wall protection film is formed and then the side wall protection film must be removed later.
This invention is a dry etching method for processing a polycide layer, in which a poly Si layer and a refractory metal silicide layer are formed in this order on an oxide film bed, by etching resist patterns selectively formed on said polycide layer into a mask, wherein the undercut 6 is provided in the refractory metal silicide layer 2 or other layers contacting the resist pattern 1 and then the refractory metal silicide layer 2 and the poly Si layer 3 are isotropically etched.
16 Citations
9 Claims
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1. A dry etching method of processing a polycide layer, comprising the steps of:
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forming a polycide layer on an oxide layer, the polycide layer being comprised of a first polysilicon layer and a refractory metal silicide layer in this order; forming a patterned resist on said polycide layer; providing an undercut in said refractory metal silicide layer which contacts the patterned resist by a first isotopical dry etching; and performing an anisotropic dry etching of said polycide layer using said patterned resist as a mask wherein a gas used in said anisotropic dry etching includes Br. - View Dependent Claims (2, 3, 4)
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5. A dry etching method of processing a polycide layer, comprising the steps of:
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forming a polycide layer on an oxide layer, the polycide layer being comprised of a first polysilicon layer and a refractory metal silicide layer in this order; forming a patterned resist on said polycide layer; providing an undercut in said refractory metal silicide layer which contacts the patterned resist; and performing an anisotropic etching of said polycide layer using said patterned resist as a mask, wherein said oxide layer is formed on a Si substrate with said first polysilicon layer and said refractory metal silicide layer formed on said oxide layer to form a polycide layer as a whole, and said step of providing an undercut is further defined as carrying out a first dry etching step with an ECR plasma etching system to provide said undercut in a portion corresponding to a section beneath the patterned resist and said step of performing an anisotropic etching is further defined as carrying out a second dry etching step and a third dry etching step, which is over-etching, by anisotropically processing the remaining refractory metal silicide layer and the first polysilicon layer, and at the same time under the condition where an appropriate selection ratio is ensured during over-etching removing the patterned resist, and comprising a final step of cleaning and drying the semiconductor wafer using a spin cleaning device. - View Dependent Claims (6, 7, 8, 9)
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Specification