Copolymers, polymer resin composition for buffer layer method of forming a pattern using the same and method of manufacturing a capacitor using the same

• US 7,776,685 B2
• Filed: 02/19/2009
• Issued: 08/17/2010
• Est. Priority Date: 08/20/2005
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Jung-Hoon, Ahn, Sun-Yul, Kang, Kyong-Rim, Kim, Young-Ho, Kim, Tae-Sung
• Primary Examiner(s): Pham; Thanhha
• Assistant Examiner(s): Tran; Tony
• Application Number:
  US12/379,348
• Publication Number:
  US 20090162986A1
• Time in Patent Office: 544 Days
• Field of Search: 438/253, 438/256, 438/396, 438/399, 257/E21.648
• US Class Current: 438/253
• CPC Class Codes: C08F 220/06 Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• CPC Class Codes: C08F 220/1806 C6-(meth)acrylate, e.g. (cyclo)hexyl (meth)acrylate or phenyl (meth)acrylate
• CPC Class Codes: C08F 220/26 Esters containing oxygen in addition to the carboxy oxygen
• CPC Class Codes: H01L 21/32139 using masks
• CPC Class Codes: H01L 28/91 made by depositing layers, e.g. by depositing alternating conductive and insulating layers

Abstract

The invention is directed to particular polymer compositions that may be generally characterized by the formula:

wherein the variables L, M and N represent the relative molar fractions of the monomers and satisfy the expressions 0<L≦0.8; 0<M≦0.2; 0<L≦0.35; and L+M+N=1; and, wherein R¹, R² and R³ are independently selected from C₁-C₆ alkyls and derivatives thereof. The invention is also directed to polymer compositions that, when used to form a buffer layer or pattern, can be more easily removed from the surface of a semiconductor substrate, thereby increasing productivity and/or reducing the likelihood of defects and failures associated with residual photoresist material.

Claims

1. A method of forming a capacitor comprising:

forming an insulating layer on a semiconductor substrate;

forming an opening in the insulating layer;

forming a conductive layer on an upper surface of the insulating layer and a lower surface and sidewalls of the opening;

forming a buffer layer on the conductive layer, the buffer layer filling the opening and including a major portion of a copolymer having from 61 to 75 weight percent benzyl methacrylate;

from 8 to 15 weight percent alkyl acrylic acid; and

with a remainder being hydroxy alkyl methacrylate;

removing an upper portion of the buffer layer using a developer solution to expose an upper portion of the conductive layer, a lower portion of the buffer layer substantially filling the opening;

removing the upper portion of the conductive layer to separate lower electrode structures;

removing the lower portion of the buffer layer;

forming a dielectric layer on the lower electrode structures; and

forming an upper electrode on the dielectric layer.

2. The method of forming a capacitor according to claim 1, wherein:

the remainder is from 17 to 24 weight percent.

3. The method of forming a capacitor according to claim 1, wherein:

the copolymer has a mean molecular weight of 6700 to 7500.

4. The method of forming a capacitor according to claim 1, wherein:

the copolymer includes at least three monomers and has a structure corresponding to Formula I;

wherein the variables L, M and N represent the relative molar fractions of the monomers and satisfy the expressions

0<

L≦

0.8;

0<

M≦

0.25;

0<

N≦

0.35; and

L+M+N=1; and

, wherein

R¹, R² and R³ are independently selected from C₁-C₆ alkyls and derivatives thereof.

5. The method of forming a capacitor according to claim 4, wherein:

the variables L and M also satisfy the expressions

45≦

L≦

0.65; and

0.15≦

M≦

0.25.

6. The method of forming a capacitor according to claim 5, wherein:

N also satisfies the expression

0.20≦

N≦

0.27.

7. The method of forming a capacitor according to claim 5, wherein:

the alkyl acrylic acid consists essentially of methyl acrylic acid and M also satisfies the expression

0.17≦

M≦

0.25.

8. The method of forming a capacitor according to claim 4, wherein:

the alkyl acrylic acid is selected from a group of consisting of the C₁-C₄ acrylic acids and mixtures thereof; and

the hydroxy alkyl methacrylate is selected from a group of consisting of the C₁-C₄ hydroxy alkyl methacrylates and mixtures thereof.

9. The method of forming a capacitor according to claim 8, wherein:

the alkyl acrylic acid includes a major portion of methyl acrylic acid; and

the hydroxy alkyl methacrylate includes a major portion of hydroxy ethyl methacrylate.

10. The method of forming a capacitor according to claim 4, wherein:

the alkyl acrylic acid consists essentially of methyl acrylic acid; and

the hydroxy alkyl methacrylate consists essentially of hydroxy ethyl methacrylate.

11. A method of forming a semiconductor device comprising:

forming an electric element on a semiconductor substrate;

forming an insulating layer on the electric element;

forming an opening in the insulating layer to expose a contact region on the electric element;

forming a conductive layer on an upper surface of the insulating layer and a lower surface and sidewalls of the opening;

forming a buffer layer on the conductive layer, the buffer layer filling the opening and including a major portion of a copolymer having from 61 to 75 weight percent benzyl methacrylate;

from 8 to 15 weight percent alkyl acrylic acid; and

with a remainder being hydroxy alkyl methacrylate;

removing an upper portion of the buffer layer using a developer solution to expose an upper portion of the conductive layer, a lower portion of the buffer layer substantially filling the opening;

removing the upper portion of the conductive layer to separate lower electrode structures;

removing the lower portion of the buffer layer and the insulating layer;

forming a dielectric layer on the lower electrode structures; and

forming an upper electrode on the dielectric layer.

12. The method of forming a semiconductor device according to claim 11, wherein:

the developer solution includes from 1 to 5 wt % tetramethyl ammonium hydroxide in an aqueous solution.

13. The method of forming a semiconductor device according to claim 12, wherein:

removing the upper portion of the buffer layer using a developer solution maintains an average removal rate of at least 30 Å

/second.

14. The method of forming a semiconductor device according to claim 11, wherein:

removing the lower portion of the buffer layer includes an ashing process that maintains an average removal rate of at least 150 Å

/second.