Method for forming pitch independent contacts and a semiconductor device having the same

• US 5,219,793 A
• Filed: 06/03/1991
• Issued: 06/15/1993
• Est. Priority Date: 06/03/1991
• Status: Expired due to Term

• Current Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Nguyen, Bich-Yen, Roman, Bernard J., Roth, Scott S., Lin, Jung-Hui, Mazure, Carlos A., Cooper, Kent J., Ray, Wayne J.
• Primary Examiner(s): QUACH, TUAN N
• Application Number:
  US07/709,554
• Time in Patent Office: 743 Days
• Field of Search: 437/195, 437/228, 437/947, 437/981, 437/241, 437/193, 437/982, 437/225, 437/229, 437/978, 156/651, 156/652, 156/653, 156/657, 156/661.1, 148/DIG. 20
• US Class Current: 438/624
• CPC Class Codes: H01L 21/76897 Formation of self-aligned vias or contact plugs, i.e. involving a lithographically uncritical step self-aligned silicidation on field effect transistors H01L29/665
• CPC Class Codes: Y10S 148/02 Contacts, special
• CPC Class Codes: Y10S 438/97 Specified etch stop material

Abstract

A contact is formed in a semiconductor device (10), independent of underlying topography or pitch. In one method of the present invention, an insulating layer (18) is deposited over a semiconductor substrate (12). An etch stop layer (20) is deposited over the insulating layer. A frame structure (22) is formed on the etch stop material and defines at least one contact region (23 and/or 25) within which the etch stop material is exposed. The exposed portions of the etch stop material are removed from the contact region to expose a portion of the insulating layer. The exposed portion of the insulating layer is then anisotropically etched and at least one contact (30 and/or 32) is formed in the contact region. Depending on where the contact region is positioned, either a self-aligned contact or a non-self-aligned contact may be formed, or both types of contacts may be formed simultaneously.

Claims

1. A method for forming a pitch-independent contact in a semiconductor device, comprising the steps of:

providing a semiconductor substrate;

depositing a first insulating layer over the semiconductor substrate;

depositing an etch stop layer of a first material which overlies the insulating layer;

depositing a second insulating layer over the etch stop layer, the second insulating layer being substantially planar and having the ability to be etches selectively to the first material;

depositing and patterning a photoresist layer on the second insulating layer;

etching the second insulating layer, using the photoresist layer as an etch mask, to form a frame structure which has a first opening formed therein, the first opening exposing all portions of the etch stop layer underlying the first opening;

removing the exposed portions of the etch stop layer to expose portions of the first insulating layer underlying the first opening;

anisotropically etching the exposed portions of the first insulating layer to form a second opening in the second insulating layer, wherein the second opening defines a contact region and wherein the second opening is smaller than the first opening; and

forming a contact in the contact region.

2. The method of claim 1 wherein the step of depositing an etch stop layer of a first material comprises depositing a conductive etch stop material.

3. The method of claim 2 further comprising the steps of:

removing the frame structure to expose remaining portions of the first material; and

removing selected portions of the remaining portions of the first material.

4. The method of claim 3 wherein the step of removing selected portions of the remaining portions of the first material comprises patterning and etching selected portions of the remaining portions of the first material to form a local interconnect.

5. The method of claim 1 wherein the step of forming a contact in the contact region comprises forming a contact to the semiconductor substrate.

6. The method of claim 1 wherein the step of forming a contact in the contact region comprises forming a contact which is separated from the semiconductor substrate by a non-conductive material.

7. The method of claim 1 wherein the step of depositing an etch stop layer comprises depositing a layer of material selected from the group consisting of polysilicon, titanium nitride (TiN), and silicon nitride (Si₃ N₄).

8. The method of claim 1 wherein the step of depositing a second insulating layer comprises depositing a second insulating layer of a second material which is compatible with temperatures in excess of 450°

C.

9. A method for forming a pitch-independent contact in a semiconductor device, comprising the steps of:

providing a semiconductor substrate having two conductive members formed thereon, each of the conductive members having an overlying dielectric layer;

conformally depositing a first insulating material over the conductive members and the semiconductor substrate;

conformally depositing a conductive etch stop layer which overlies the first insulating material;

depositing a second insulating material overlying the conductive etch stop layer;

etching the second insulating material selective to the underlying conductive etch stop layer to form a disposable frame structure which defines first and second spaced apart contact regions, the first contact region overlying at least a portion of one of the two conductive members and the conductive etch stop layer being exposed within both the first and second contact regions;

removing the conductive etch stop layer exposed within the first and second contact regions to expose a portion of the first insulating material within each contact region;

anisotropically etching the exposed portions of the first insulating material to form at least one sidewall spacer along a side of one of the conductive members and to expose a portion of the semiconductor substrate within the first contact region;

forming a first contact in the first contact region which is electrically coupled to the exposed portion of the semiconductor substrate;

removing the disposable frame structure to expose remaining portions of the conductive etch stop layer; and

etching portions of the exposed conductive etch stop layer.

10. The method of claim 9 wherein the step of forming a contact comprises depositing a blanket layer of conductive material onto the semiconductor device and subsequently etching the blanket layer of conductive material to form a contact.

11. The method of claim 9 wherein the step of depositing a conductive etch stop layer comprises depositing polysilicon.

12. The method of claim 11 wherein the step of etching the second insulating material selective to the underlying conductive etch stop layer comprises etching the second insulating material selective to the underlying conductive etch stop layer by using a plasma etch which employs CF₄, CHF₃, and argon gases.

etching portions of the exposed conductive etch stop layer.

13. The method of claim 9 wherein the step of etching portions of the exposed conductive etch stop layer comprises removing all exposed portions of the conductive etch stop layer.

14. The method of claim 9 wherein the step of etching portions of the exposed conductive etch stop layer comprises etching portions of the exposed conductive etch stop layer to form a local interconnect.

15. The method of claim 9 further comprising the step of forming a second contact in the second contact region.

16. The method of claim 15 wherein the step of forming a second contact comprises forming a second contact which is separated from the semiconductor substrate by a non-conductive material.

17. The method of claim 15 wherein the step of forming a second contact comprises forming a second contact which is in electrical contact with the semiconductor substrate.

18. The method of claim 15 further comprising the step of forming a local interconnect from the portions of the conductive etch stop layer exposed as a result of removing the disposable frame structure, the local interconnect being electrically coupled to the first contact.

19. The method of claim 15 further comprising the step of forming a local interconnect from the portions of the conductive etch stop layer exposed as a result of removing the disposable frame structure, the local interconnect being electrically coupled to the second contact.

20. A method for forming a pitch-independent contact in a semiconductor device, comprising the steps of:

providing a semiconductor substrate;

depositing a first insulating layer over the semiconductor substrate;

depositing an etch stop layer which overlies the first insulating layer;

depositing a second insulating layer overlying the etch stop layer, the second insulating layer having the ability to be etched selectively to the etch stop layer;

patterning the second insulating layer to form a frame structure, the frame structure having an opening which defines a contact region and exposes the etch stop layer within the contact region;

removing the exposed etch stop layer within the contact region to expose a portion of the first insulating layer;

anisotropically etching the exposed portion of the insulating layer within the contact region;

forming a contact in the contact region; and

removing the frame structure from the device.

21. The method of claim 20 wherein the step of depositing an etch stop layer comprises depositing a conductive etch stop layer.

22. The method of claim 21 wherein the step of removing the frame structure comprises removing the frame structure to expose remaining portions of the etch stop layer, and further comprising the step of removing portions of the etch stop layer which become exposed as a result of removing the frame structure.

23. The method of claim 22 wherein the step of removing portions of the etch stop layer which become exposed as a result of removing the frame structure comprises removing all portions of the etch stop layer which become exposed as a result of removing the frame structure.

24. The method of claim 22 wherein the step of removing portions of the etch stop layer which become exposed as a result of removing the frame structure comprises removing portions of the etch stop layer which become exposed as a result of removing the frame structure to form a local interconnect.