Metallized substrate

• US 5,616,422 A
• Filed: 05/09/1995
• Issued: 04/01/1997
• Est. Priority Date: 02/28/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Gaudiello, John G., Ballard, Gerald L.
• Primary Examiner(s): ZIMMERMAN, JOHN J
• Application Number:
  US08/437,753
• Time in Patent Office: 693 Days
• Field of Search: 428/601, 428/621, 428/624, 428/625, 428/626, 428/674, 428/936, 174/256
• US Class Current: 428/621
• CPC Class Codes: C23C 18/40 using reducing agents
• CPC Class Codes: H05K 3/24 Reinforcing the conductive pattern by solder coating H05K3/3457
• CPC Class Codes: H05K 3/244 Finish plating of conductors, especially of copper conductors, e.g. for pads or lands selective plating methods H05K3/243; finish plating of conductors made by printing techniques H05K3/246; solder as finish H05K3/3457, e.g. by plating H05K3/3473
• CPC Class Codes: Y10S 428/936 Chemical deposition, e.g. electroless plating
• CPC Class Codes: Y10T 428/12535 with additional, spatially distinct nonmetal component
• CPC Class Codes: Y10T 428/12903 Cu-base component

Abstract

An electroless metal plating bath composition, a corresponding method for electrolessly depositing a metal onto a substrate surface, as well as the resulting, metallized substrate, are disclosed. The inventive bath composition includes water, a soluble source of the metal ions it is desired to chemically reduce at, and deposit onto, the substrate surface of interest, and a complexing agent for the metal ions. In addition, the bath composition includes a soluble source of any one or more of a select group of what are termed mediator ions, which group includes palladium (Pd), platinum (Pt), silver (Ag), ruthenium (Ru), iridium (Ir), osmium (Os) and rhodium (Rh) ions, as well as a complexing agent for the mediator ions. Moreover, the bath composition includes a chemical reducing agent, which primarily serves to chemically reduce the mediator ions at the substrate surface of interest. Significantly, by using an appropriate ratio of the concentration of the metal ions in solution to the concentration of the mediator ions in solution, and depending upon which mediator ions are used, the inventive bath composition serves to electrolessly deposit the metal of interest onto the substrate surface of interest, with the resulting deposited metal containing less than or equal to about 3.0 atomic percent, or less than or equal to about 2.0 atomic percent, or even less than or equal to about 1.0 atomic percent, of the corresponding mediator metal.

Claims

1. A device, comprising:

an electrically insulating substrate;

a first metallic layer overlying said substrate;

an electrolessly deposited, second metallic layer overlying said first metallic layer, a composition of said second layer consisting of about 97 atomic percent or more of a first metal and about 0.22 to about 3.0 atomic percent of a second metal substantially uniformly distributed throughout said first metal, said second metal being chosen from the group consisting of palladium, platinum, silver, ruthenium, iridium, osmium and rhodium, said second metallic layer including trace amounts of phosphorus or boron.

2. The device of claim 1, wherein said first metal is copper.

3. The device of claim 1, wherein said first metallic layer is patterned and said second metallic layer is correspondingly patterned.

4. A device, comprising:

an electrically insulating substrate;

a first metallic layer overlying said substrate;

an electrolessly deposited, second metallic layer overlying said first metallic layer, a composition of said second layer consisting of about 98 atomic percent or more of a first metal and about 0.22 to about 2.0 atomic percent of a second metal substantially uniformly distributed throughout said first metal, said second metal being chosen from the group consisting of palladium, platinum and silver, said second metallic layer including trace amounts of phosphorus or boron.

5. The device of claim 4, wherein said first metal is copper.

6. The device of claim 4, wherein said first metallic layer is patterned and said second metallic layer is correspondingly patterned.

7. A device, comprising:

an electrically insulating substrate;

a first metallic layer overlying said substrate; and

an electrolessly deposited, second metallic layer overlying said first metallic layer, a composition of said second layer consisting of about 99 atomic percent or more of a first metal and about 0.22 to about 1.0 atomic percent of a second metal, palladium, substantially uniformly distributed throughout said first metal, said second metallic layer including trace amounts of phosphorus or boron.

8. The device of claim 7, wherein said first metal is copper.

9. The device of claim 7, wherein said first metallic layer is patterned and said second metallic layer is correspondingly patterned.