Semiconductor device having box-shaped cylindrical storage nodes and fabrication method thereof

• US 7,273,780 B2
• Filed: 05/26/2005
• Issued: 09/25/2007
• Est. Priority Date: 06/24/2004
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Sang-Ho
• Primary Examiner(s): LUU, CHUONG A
• Application Number:
  US11/137,440
• Publication Number:
  US 20050285176A1
• Time in Patent Office: 852 Days
• Field of Search: 438/253, 438/244, 438/396, 438/445, 438/190, 438/239, 438/250
• US Class Current: 438/253
• CPC Class Codes: H01L 21/76816 Aspects relating to the layout of the pattern or to the size of vias or trenches layout of the interconnections per se H01L23/528; CAD of ICs G06F30/00
• CPC Class Codes: H01L 28/91 made by depositing layers, e.g. by depositing alternating conductive and insulating layers
• CPC Class Codes: H10B 12/033 the capacitor extending over the transistor

Abstract

A method of forming box-shaped cylindrical storage nodes includes forming an interlayer insulating layer on a semiconductor substrate. Buried contact plugs are formed to penetrate the interlayer insulating layer. A molding layer and a photoresist layer are then sequentially formed on the substrate. Using a first phase shift mask having line-and-space patterns, the photoresist layer is exposed, forming first exposure regions. Using a second phase shift mask having line-and-space patterns, the photoresist layer is exposed again, forming second exposure regions intersecting the first exposure regions. The photoresist layer is then developed, forming a photoresist pattern having rectangular-shaped openings formed at intersections of the first and the second exposure regions. The molding layer is etched using the photoresist pattern as an etch mask, forming storage node holes exposing the buried contact plugs. Storage nodes are formed inside the storage node holes.

Claims

1. A method of fabricating a semiconductor device, comprising:

forming an interlayer insulating layer on a semiconductor substrate;

forming buried contact plugs penetrating the interlayer insulating layer;

sequentially forming a molding layer and a photoresist layer on the semiconductor substrate having the buried contact plugs formed thereon;

exposing the photoresist layer using a first phase shift mask having line-and-space type patterns, to form first exposure regions;

exposing the photoresist layer having the first exposure regions, using a second phase shift mask having line-and-space type patterns, to form second exposure regions intersecting the first exposure regions;

developing the photoresist layer having the first and the second exposure regions, to form a photoresist pattern having rectangular-shaped openings, the rectangular-shaped openings being formed at cross points of the first and the second exposure regions;

using the photoresist pattern in a process of etching the molding layer to form storage node holes exposing the buried contact plugs; and

forming storage nodes inside the storage node holes.

2. The method of claim 1, further comprising after forming the molding layer, forming a hard mask layer on the molding layer, and wherein using the photoresist pattern in the process of etching the molding layer to form the storage node holes exposing the buried contact plugs comprises,

patterning the hard mask layer using the photoresist pattern as an etch mask, to form a hard mask pattern;

and

etching the molding layer using the hard mask pattern as an etch mask to form the storage node holes exposing the buried contact plugs.

3. The method according to claim 2, wherein the hard mask layer is formed of a material layer having an etch selectivity relative to the molding layer.

4. The method according to claim 1, wherein a thickness of one of the first exposure regions and the second exposure regions is smaller than a thickness of the photoresist layer, and a thickness of the overlapping exposure regions of the first exposure regions and the second exposure regions is the same as the thickness of the photoresist layer.

5. The method according to claim 1, wherein the pattern intervals of the line-and-space type patterns in the first phase shift mask and the second phase shift mask are the same.

6. The method according to claim 1, further comprising, after forming the buried contact plugs, forming buffer conductive layer patterns on the semiconductor substrate having the buried contact plugs formed thereon, the buffer conductive layer patterns being in contact with the buried contact plugs and having a wider area than the buried contact plugs.

7. The method according to claim 1, further comprising, after forming the buried contact plugs, forming an etch stop layer on the semiconductor substrate having the buried contact plugs, and

wherein forming the storage node holes comprises sequentially etching the molding layer and the etch stop layer, to form storage node holes exposing the buried contact plugs.

8. The method according to claim 1, further comprising, after forming the storage node holes, cleaning the inside of the storage node holes using a wet cleaning solution.

9. A method of fabricating a semiconductor device, comprising:

forming an interlayer insulating layer on a semiconductor substrate;

forming buried contact plugs penetrating the interlayer insulating layer;

sequentially forming a molding layer, a first hard mask layer, and a second hard mask layer on the semiconductor substrate having the buried contact plugs formed thereon;

patterning the second hard mask layer, to form line-and-space type upper hard mask patterns;

patterning the first hard mask layer to form line-and-space type lower hard mask patterns, wherein the lines of the lower hard mask patterns are arranged at an angle with respect to the lines of the upper hard mask pattern when viewed from a plan view, above;

etching the molding layer using the upper and the lower hard mask patterns as etch masks to form storage node holes exposing the buried contact plugs; and

forming storage nodes inside the storage node holes.

10. The method according to claim 9, wherein the pattern intervals of the line-and-space type patterns in the lower hard mask patterns and the upper hard mask patterns are the same.

11. The method according to claim 9, wherein the first hard mask layer is formed of a material layer having an etch selectivity relative to the molding layer.

12. The method according to claim 9, wherein the second hard mask layer is formed of a material layer having an etch selectivity relative to the molding layer.

13. The method according to claim 9, wherein the second hard mask layer is formed of a material layer having an etch selectivity relative to the first hard mask layer.

14. The method according to claim 9, further comprising, after forming the buried contact plugs, forming buffer conductive layer patterns on the semiconductor substrate having the buried contact plugs formed thereon, the buffer conductive layer patterns being in contact with the buried contact plugs and having a wider area than the buried contact plugs, and

wherein forming the storage node holes comprises etching the molding layer using the upper and the lower hard mask patterns as etch masks to form the storage node holes exposing the buffer conductive layer patterns.

15. The method according to claim 9, further comprising, after forming the buried contact plugs, forming an etch stop layer on the semiconductor substrate having the buried contact plugs, and

wherein forming the storage node holes comprises sequentially etching the molding layer and the etch stop layer using the upper and the lower hard mask patterns as etch masks, to form storage node holes exposing the buried contact plugs.

16. The method according to claim 9, further comprising, after forming the storage node holes, cleaning the inside of the storage node holes using a wet cleaning solution.

17. A method of fabricating a semiconductor device, comprising:

forming an interlayer insulating layer on a semiconductor substrate;

forming buried contact plugs penetrating the interlayer insulating layer;

sequentially forming a molding layer and a hard mask layer on the semiconductor substrate having the buried contact plugs formed thereon;

patterning the hard mask layer to form line-and-space type hard mask patterns;

forming a photoresist layer on the semiconductor substrate having the hard mask patterns;

patterning the photoresist layer to form line-and-space type photoresist patterns, wherein the lines of the photoresist patterns are arranged at an angle with respect to the lines of the hard mask pattern when viewed from a plan view, above;

etching the molding layer using the photoresist patterns and the hard mask patterns as etch masks to form storage node holes exposing the buried contact plugs; and

forming storage nodes inside the storage node holes.

18. The method according to claim 17, wherein the pattern intervals of the line-and-space type patterns in the photoresist patterns and the hard mask patterns are same.

19. The method according to claim 17, wherein the hard mask patterns are formed of a material layer having an etch selectivity relative to the molding layer.

20. The method according to claim 17, further comprising, after forming the buried contact plugs, forming buffer conductive layer patterns on the semiconductor substrate having the buried contact plugs formed thereon, the buffer conductive layer patterns being in contact with the buried contact plugs and having a wider area than the buried contact plugs, and

wherein forming the storage node holes comprises etching the molding layer using the photoresist patterns and the hard mask patterns as etch masks, to form the storage node holes exposing the buffer conductive layer patterns.

21. The method according to claim 17, further comprising, after forming the buried contact plugs, forming an etch stop layer on the semiconductor substrate having the buried contact plugs, and

wherein forming the storage node holes comprises sequentially etching the molding layer and the etch stop layer using the photoresist patterns and the hard mask patterns as etch masks, to form the storage node holes exposing the buried contact plugs.

22. The method according to claim 17, after forming the storage node holes, the method further comprising cleaning the inside of the storage node holes using a wet cleaning solution.