Electroless plating liquid and semiconductor device

• US 6,717,189 B2
• Filed: 06/14/2001
• Issued: 04/06/2004
• Est. Priority Date: 06/01/2001
• Status: Expired due to Term

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Nakamura, Kenji, Inoue, Hiroaki, Matsumoto, Moriji
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): TRAN, MAI HUONG C
• Application Number:
  US09/880,005
• Publication Number:
  US 20020185658A1
• Time in Patent Office: 1,027 Days
• Field of Search: 313/582, 313/584, 313/585, 313/586, 427/35, 427/36, 427/304, 428/209, 106/1.11, 106/1.23, 96/384
• US Class Current: 257/200
• CPC Class Codes: C23C 18/1607 by direct patterning
• CPC Class Codes: C23C 18/1635 Composition of the substrate
• CPC Class Codes: C23C 18/34 using reducing agents
• CPC Class Codes: C23C 18/50 with alloys based on iron, cobalt or nickel
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/0209 Cleaning of wafer backside
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• CPC Class Codes: H01L 21/6723 comprising at least one plating chamber electroless plating apparatuses C23C, electroplating apparatuses C25D
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: Y10S 428/901 Printed circuit
• CPC Class Codes: Y10T 428/24917 including metal layer

Abstract

The present invention relates to an electroless-plating liquid useful for forming a protective film for selectively protecting surface of exposed interconnects of a semiconductor device which has an embedded interconnect structure formed by an electric conductor, such as copper or silver, embedded in fine recesses for interconnects formed in a surface of a semiconductor substrate, and also to a semiconductor device in which surfaces of exposed interconnects are selectively protected with a protective film. The electroless-plating liquid contains cobalt ions, a complexing agent and a reducing agent containing no alkali metal.

Claims

1. A semiconductor device comprising:

an interconnect made of copper, copper alloy, silver, or silver alloy, embedded in a trench in a surface of an insulating film, wherein said trench is covered by a barrier layer; and

a protective film having a thickness in a range of from 0.1 nm to 500 nm, said protective film selectively covering an exposed surface of said interconnect, and said protective film being formed by an electroless-plating process using an electroless-plating liquid without using palladium, said electroless-plating liquid comprising;

(i) cobalt ions;

(ii) a complexing agent; and

(iii) an alkylamine borane that is free from alkali metal.

2. The semiconductor device according to claim 1, wherein said electroless-plating liquid further comprises at least one of

(i) a stabilizer selected from one or more kinds of heavy metal compounds and sulfur compounds, and

(ii) a surfactant.

3. The semiconductor device according to claim 1, wherein said electroless-plating liquid has a pH adjusting agent that is free from alkali metal.

4. The semiconductor device according to claim 1, wherein said protective film has a thickness within a range of from 10 nm to 100 nm.

5. A semiconductor device comprising:

an interconnect made of copper, copper alloy, silver, or silver alloy, embedded in a trench in a surface of an insulating film, wherein said trench is covered by a barrier layer; and

a protective film having a thickness in a range of from 0.1 nm to 500 nm, said protective film selectively covering an exposed surface of said interconnect, and said protective film being formed by an electroless-plating process using an electroless-plating liquid without using palladium, said electroless-plating liquid comprising;

(i) cobalt ions;

(ii) a complexing agent;

(iii) a compound containing a refractory metal; and

(iv) an alkylamine borane that is free from alkali metal.

6. The semiconductor device according to claim 5, wherein said refractory compound comprises at least one of tungsten and molybdenum.

7. The semiconductor device according to claim 5, wherein said electroless-plating liquid further comprises at least one of

(i) a stabilizer selected from one or more kinds of heavy metal compounds and sulfur compounds, and

(ii) a surfactant.

8. The semiconductor device according to claim 5, wherein said electroless-plating liquid has a pH adjusting agent that is free from alkali metal.

9. The semiconductor device according to claim 5, wherein said protective film has a thickness within a range of from 10 nm to 100 nm.