# US 10,483,445 B2 · Lead frame, package for light emitting device, light emitting device, and method for manufacturing light emitting device

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- Number: US 10,483,445 B2
- Document ID: US10483445B2
- Status: Granted
- Kind: B2
- Application number: 16/043,364
- Filed: 2018-07-24
- Published: 2019-02-28
- Granted: 2019-11-19
- Earliest claimed: 2017-08-31
- Assignees: Nichia Corporation
- Applicants: Nichia Corporation
- Inventors: Yasuo Kato
- Web page: https://patentgrep.com/patent/US10483445B2

## CPC

- H10H 20/857: Interconnections, e.g. lead-frames, bond wires or solder balls
- C25D 3/46: of silver
- C25D 5/10: Electroplating with more than one layer of the same or of different metals (for bearings C25D7/10)
- C25D 5/611: {Smooth layers}
- C25D 5/617: {Crystalline layers}
- C25D 5/627: {Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance}
- H10H 20/8506: {Containers}
- H10H 20/856: Reflecting means
- H10H 20/036: {of packages}
- H10H 20/0363: {of optical field-shaping means}
- H10H 20/0364: {of interconnections}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR

## Abstract

A lead frame includes a base material and two or more silver-containing layers. The base material is composed of a metal. The two or more silver-containing layers are stacked on the base material. The two or more silver-containing layers includes an uppermost silver-containing layer containing sulfur, and a lower silver-containing layer. The lower silver-containing layer contains no selenium or the lower silver-containing layer is composed substantially only of silver. A method for manufacturing a light emitting device includes: preparing a lead frame; preparing a package including the lead frame; and mounting a light emitting element on the package. The lead frame is prepared by: providing a base material; forming an underlying metal on the base material by plating to form an underlayer; and forming two or more silver-containing stacked layers on the underlayer, the two or more silver-containing stacked layers including an uppermost silver-containing layer containing sulfur.

## Claims

### Claim 1

A lead frame comprising:
a base material composed of a metal; and
two or more silver-containing layers stacked on the base material, the two or more silver-containing layers including
an uppermost silver-containing layer containing organic sulfur, and
a lower silver-containing layer, with the lower silver-containing layer containing no selenium or the lower silver-containing layer being composed substantially only of silver.

### Claim 2 (depends on 1)

The lead frame according to claim 1, wherein
a concentration of elemental sulfur in the uppermost silver-containing layer is 20 ppm to 250 ppm by weight.

### Claim 3 (depends on 1)

The lead frame according to claim 1, wherein
a glossiness in the uppermost silver-containing layer is from 0.3 to 1.4.

### Claim 4 (depends on 1)

The lead frame according to claim 1, wherein
a total thickness of the two or more silver-containing layers is 0.05 μm to 5 μm, and a ratio of the uppermost silver-containing layer and the lower silver-containing layer is 1:1 to 1:99.

### Claim 5 (depends on 1)

The lead frame according to claim 1, further comprising
an underlayer in between the base material and the silver-containing layer.

### Claim 6 (depends on 5)

The lead frame according to claim 5, wherein
the underlayer includes a layer composed of one or more metals selected from the group consisting of copper, nickel, palladium and gold.

### Claim 7 (depends on 1)

The lead frame according to claim 1, wherein
the lead frame has a substantially flat shape with no bent parts.

### Claim 8 (depends on 1)

A package comprising:
a substrate; and
the lead frame according to claim 1, embedded in the substrate with at least a part of the uppermost silver-containing layer being exposed from the substrate.

### Claim 9 (depends on 8)

A light emitting device comprising:
the package according to claim 8; and
a light emitting element mounted on an upper surface of the uppermost silver-containing layer exposed from the substrate.

### Claim 10 (depends on 9)

The light emitting device according to claim 9, further comprising
a wire connecting the light emitting element and the uppermost silver-containing layer, the wire being made of one of gold, silver, a silver alloy, copper, a copper core covered with palladium, and a copper core covered with palladium silver.

### Claim 11

A method for manufacturing a light emitting device, comprising:
preparing a lead frame by
providing a base material,
forming an underlying metal on the base material by plating to form an underlayer, and
forming two or more silver-containing stacked layers on the underlayer, by forming one or more lower silver-containing layer, and by forming an uppermost silver-containing layer containing sulfur by using material containing at least silver and sulfur;
preparing a package including the lead frame; and
mounting a light emitting element on the package.

### Claim 12 (depends on 11)

The method for manufacturing a light emitting device according to claim 11, wherein
the forming of the two or more silver-containing stacked layers is performed by electroplating.

### Claim 13 (depends on 11)

The method for manufacturing a light emitting device according to claim 11, wherein
the providing of the base material includes forming the base material by rolling.