US 7,115,491 B2 · Method for forming self-aligned contact in semiconductor device

Abstract

A method for forming a self-aligned contact on a semiconductor substrate provided with a plurality of field-effect transistors. The method comprises the steps of: forming a thin nitride insulating layer on a gate structure and a diffusion region of the transistor; forming a first insulating layer, which is then planarized to expose the nitride insulating layer on the gate structure; etching through the first insulating layer to form a first part of a contact hole; forming a first part of a contact in said first part of the contact hole; forming a second insulating layer; etching through the second insulating layer to form a second part of the contact hole; and forming a second part of the contact in the second part of the contact hole. The two-stage etching process for forming a conductive contact effectively prevents over-etching and short-circuiting between a wordline and a bitline.

Claims16

Dependent claims

A method for forming a self-aligned contact in a semiconductor device, comprising the steps of:

(a) providing a substrate having at least one gate structure and at least one diffusion region adjacent said gate structure;
(b) forming a thin layer along a profile of said gate structure, including an entire top portion of said gate structure, and said diffusion region;
(c) forming a first insulating layer at least covering said gate structure and said diffusion region;
(d) removing a portion of said first insulating layer to expose the entire portion of said thin layer atop said gate structure;
(e) forming a first part of a contact hole through said first insulating layer and exposing at least a portion of said diffusion region;
(f) forming a first part of a contact in said first part of said contact hole;
(g) forming a second insulating layer at least covering said gate structure and said first part of said contact;
(h) forming a second part of said contact hole through said second insulating layer and exposing at least a portion of said first part of said contact;
and
(i) forming a second part of said contact in said second part of said contact hole.

7 more elements

A method for forming a self-aligned contact in a semiconductor device, comprising the steps of:

(a) providing a substrate having a plurality of gate structures and diffusion regions adjacent said gate structures, each of said gate structures including a conductive layer;
(b) forming a thin layer along a profile of said gate structures, including an entire top portion of said gate structure, has been inserted after “said gate and said diffusion regions;
(c) forming a first insulating layer at least covering said gate structures and said diffusion regions;
(d) removing a portion of said first insulating layer to expose the entire portion of said thin layer atop said gate structures;
(e) forming a first part of a first type contact hole through one of said gate structures and exposing at least a portion of said conductive layer of said gate structure;
(f) forming a first part of a second type contact hole through said first insulating layer and exposing at least a portion of said diffusion region;
(g) simultaneously forming a first part of a first type contact and a first part of a second type contact in said first part of said first type contact hole and said first part of said second type contact hole, respectively;
(h) forming a second insulating layer at least covering said gate structures, said first part of said first type contact and said first part of said second type contact;
(i) simultaneously forming a second part of said first type contact hole and a second part of said second type contact hole through said second insulating layer and exposing at least a portion of said first part of said first type contact and at least a portion of said first part of said second type contact;
and
(j) simultaneously forming a second part of said first type contact and a second part of said second type contact in said second part of said first type contact hole and said second part of said second type contact hole, respectively.

8 more elements

Dependencies are inferred from the claim text.

Method for forming self-aligned contact in semiconductor device

Life of this patent

Method for forming self-aligned contact in semiconductor device

Life of this patent

Abstract

Claims16