Dry etching method

Claim 2

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.

Claim 3

A dry etching method according to claim 1, wherein the first isotropical dry etching is performed in an ECR plasma etching system.

Claim 4

A dry etching method according to claim 1, wherein said polycide layer to be etched has a stacking structure for forming a silicon-based electrode layer.

Claim 5

A dry etching method according to claim 1, wherein the gas used in the second etching step is selected from the group consisting of SF 6 /HBr, Cl 2 /O 2 and Cl 2 /HBr.

Claim 6

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; 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.

Claim 7

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; 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.

Claim 8

A dry etching method according to claim 5, wherein the gas used in the first etching step is SF 6 .

Claim 9

A dry etching method according to claim 5, wherein the gas used in the second etching step is selected from the group consisting of SF 6 /HBr, Cl 2 /O 2 and Cl 2 /HBr.

Claim 10

A dry etching method according to claim 5, wherein the gas used in the third etching step is O 2 /HBr.

Claim 11

A dry etching method according to claim 8, wherein the gas used in the first etching step is SF 6 and the gas used in the second etching step is selected from a group consisting of SF 6 /HBr, Cl 2 /O 2 and Cl 2 /HBr.