Laser marking method and ablative coating for use therein

• US 4,707,722 A
• Filed: 01/09/1987
• Issued: 11/17/1987
• Est. Priority Date: 12/17/1984
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Asher, Reginald K., Folk, Lee E.
• Primary Examiner(s): James, Andrew J.
• Assistant Examiner(s): CLARK, SHEILA V
• Application Number:
  US07/004,779
• Time in Patent Office: 312 Days
• Field of Search: 357/67, 357/71, 357/68, 357/65, 427/305, 427/304, 427/53.1, 174/52 FP
• US Class Current: 257/741
• CPC Class Codes: B41M 5/262 recording or marking of inorganic surfaces or materials, e.g. glass, metal, or ceramics marking of plastic artifacts with inorganic additives B41M5/267
• CPC Class Codes: C23C 18/06 Coating on selected surface areas, e.g. using masks
• CPC Class Codes: C23C 18/143 Radiation by light, e.g. photolysis or pyrolysis
• CPC Class Codes: C23C 18/32 Coating with nickel, cobalt or mixtures thereof with phosphorus or boron C23C18/50 takes precedence
• CPC Class Codes: C23F 4/02 by evaporation
• CPC Class Codes: H01L 2223/54433 containing identification or tracking information
• CPC Class Codes: H01L 2223/54486 Located on package parts, e.g. encapsulation, leads, package substrate
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Laser marking of metal surfaces, particularly semiconductor device packages, is accomplished by depositing an electroless nickel layer on the surface, converting the nickel surface to a form in which it is highly absorptive of radiant energy and exposing the converted nickel surface to laser energy through a mask. The resulting mark is highly resistant to abrasion and corrosion. In addition, the method is highly suitable for use with automated laser marking equipment. Furthermore, it appears that the presence of the converted electroless nickel surface in the region of welds increases the hermeticity of the welds. This is particularly useful in packages of the TO-3 type and similar types.

Claims

1. A semiconductor device package comprising:

at least one metal surface;

a layer of nickel coating said at least one metal surface, said layer of nickel having an upper portion converted to a radiant energy absorptive form, said upper portion defining an opening therethrough exposing a lower nonconverted portion of said layer of nickel.

2. A package according to claim 1 wherein:

said upper portion of said layer of nickel comprises an electroless nickel layer which has been exposed to an acid solution.

3. A package according to claim 2 wherein said acid solution comprises:

nitric acid; and

acetic acid.

4. A package according to claim 1 wherein said upper portion of said layer of nickel is approximately 10-20 microinches in thickness.

5. A package according to claim 1

wherein the opening defined by said upper portion of said layer of nickel was created by removing a portion of said upper portion of said layer of nickel by exposure to radiant energy.

6. A semiconductor device package comprising:

a substrate having a first surface;

an inner portion of a nickel layer having a first surface and a second surface connected to said first surface of said substrate; and

an upper converted portion of said nickel layer absorptive of laser energy, said upper converted portion having a first surface connected to said first surface of said nickel layer.

7. The semiconductor device package of claim 6 wherein said upper converted portion of said nickel layer defines at least one opening therethrough.

8. The semiconductor device package of claim 7 wherein the at least one opening of siad upper converted portion of said nickel layer is representative of a semiconductor device contained in said semiconductor device package.