US5889317A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Leadframe for integrated circuit package
Assignee: Fu Sheng Industrial Co Ltd
•
Filing: 1997-06-06
•
Granted: 1999-03-30
•
Expires: 2017-06-06
Abstract
Abstract A leadframe for an IC package and a method of manufacturing the same are provided. The leadframe can be manufactured in such a manner as to provide suitable bondability, molding compound characteristic, and solderability. The leadframe includes a base structure made from a conductive material. A silver plating is formed over the base structure of the leadframe, and a palladium plating is formed over the silver plating. Depending on actual requirements, a copper layer and a nickel plating can be formed between the silver plating and the base structure of the leadframe, and a palladium/nickel plating can be found between the silver and palladium platings. Further, a gold layer can be formed over the palladium plating. The palladium plating and the palladium/nickel plating can be formed all over the leadframe or selectively formed only in the external-lead area of the leadframe. The structure of the layering of one silver layer beneath the palladium plating allows the prevention of the occurrence of pin holes in the platings so that the bondability and solderability of the leadframe can be assured.
Inventors
- 👤 Chih-Kung Huang
- 👤 Wei-Jen Lai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:38
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/456; H10W70/457; H10W72/00; H10W72/071; H10W72/073; H10W72/07351; H10W72/07352; H10W72/075; H10W72/30; H10W72/321; H10W72/351; H10W72/352; H10W72/353; H10W72/354; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/59; H10W72/851; H10W72/874; H10W72/884; H10W72/90; H10W72/951; H10W72/952; H10W74/00; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
73 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a first silver layer formed selectively over the base structure of the leadframe; and a palladium plating formed over the first silver layer.
Claim 2
Dependent Claim
73 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a first silver layer formed selectively over the base structure of the leadframe; and a palladium plating formed over the first silver layer.
Claim 3
Dependent Claim
16 words
The leadframe of claim 1, wherein said base structure is made from an alloy of copper.
Claim 4
Dependent Claim
16 words
The leadframe of claim 1, wherein said base structure is made from an alloy of nickel/ferrite.
Claim 5
Dependent Claim
56 words
The leadframe of claim 1, wherein said first silver layer is formed selectively only in the bonding area and external-lead area; said leadframe further includes a second silver layer formed over the first silver layer in the bonding area; and said palladium plating is formed selectively only over the first silver layer in the external-lead area.
Claim 6
Dependent Claim
21 words
The leadframe of claim 4, further including: a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 7
Dependent Claim
53 words
The leadframe of claim 4, further including: a palladium/nickel plating formed selectively only over the first silver layer in the external-lead area such that said palladium/nickel plating is layered between said first silver layer and said palladium plating; and a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 8
Dependent Claim
66 words
The leadframe of claim 1, wherein said first silver layer is formed selectively only over the base structure in the external lead area and the bonding area excluding the die pad; said leadframe further includes a second silver layer formed over the first silver layer in the bonding area; and said palladium plating is formed selectively only over the first silver layer in the external-lead area.
Claim 9
Dependent Claim
38 words
The leadframe of claim 7, further including: a palladium/nickel plating formed selectively only over the first silver layer in the external-lead area such that said palladium/nickel plating is layered between said first silver layer and said palladium plating.
Claim 10
Dependent Claim
21 words
The leadframe of claim 7, further including: a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 11
Dependent Claim
53 words
The leadframe of claim 7, further including: a palladium/nickel plating formed selectively only over the first silver layer in the external-lead area such that said palladium/nickel plating is layered between said first silver layer and said palladium plating; and a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 12
Dependent Claim
40 words
The leadframe of claim 1, wherein said first silver layer is formed selectively only over the base structure in the bonding area and the external-lead area; and said palladium plating is formed over the entire base structure of the leadframe.
Claim 13
Dependent Claim
36 words
The leadframe of claim 1, wherein said first silver layer is formed selectively only over the base structure in the bonding area; and said palladium plating is formed over the entire base structure of the leadframe.
Claim 14
Dependent Claim
101 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a copper layer formed over said base structure; a nickel plating formed over said copper layer; a silver layer formed over the nickel plating in the bonding area; and a palladium plating formed over the silver layer and those portions of the nickel plating that are uncovered by the silver layer.
Claim 15
Dependent Claim
101 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a copper layer formed over said base structure; a nickel plating formed over said copper layer; a silver layer formed over the nickel plating in the bonding area; and a palladium plating formed over the silver layer and those portions of the nickel plating that are uncovered by the silver layer.
Claim 16
Dependent Claim
130 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a copper layer formed over said base structure; a nickel plating formed over said copper layer; a first silver layer formed selectively only over the nickel plating in the bonding area and the external-lead area; a second silver layer selectively only over the first silver layer in the bonding area; a palladium plating formed selectively only over the first silver layer in the external-lead area; and a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 17
Dependent Claim
130 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a copper layer formed over said base structure; a nickel plating formed over said copper layer; a first silver layer formed selectively only over the nickel plating in the bonding area and the external-lead area; a second silver layer selectively only over the first silver layer in the bonding area; a palladium plating formed selectively only over the first silver layer in the external-lead area; and a gold layer formed selectively only over the palladium plating in the external-lead area.
Claim 18
Dependent Claim
79 words
A leadframe for an IC package to mount a semiconductor chip thereon comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a silver layer formed over the entire base structure of the leadframe: a palladium/nickel plating formed over the silver layer and a palladium plating formed over the palladium/nickel plating.
Claim 19
Dependent Claim
79 words
A leadframe for an IC package to mount a semiconductor chip thereon comprising: a base structure of a conductive material, the base structure including an external-lead area and a package area including a bonding area said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a silver layer formed over the entire base structure of the leadframe: a palladium/nickel plating formed over the silver layer and a palladium plating formed over the palladium/nickel plating.
Claim 20
Dependent Claim
20 words
The leadframe of claim 4, further including: a nickel layer formed between said base structure and said first silver layer.
Claim 21
Dependent Claim
20 words
The leadframe of claim 4, further including: a copper layer formed between said base structure and said first silver layer.
Claim 22
Dependent Claim
29 words
The leadframe of claim 4, further including: a copper layer formed over said base structure; and a nickel layer formed between said copper layer and said first silver layer.
Claim 23
Dependent Claim
38 words
The leadframe of claim 4, further including: a palladium/nickel plating formed selectively only over the first silver layer in the external-lead area such that said palladium/nickel plating is layered between said first silver layer and said palladium plating.
Claim 24
Dependent Claim
74 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of an alloy of nickel/ferrite, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a first silver layer formed over the entire base structure of the leadframe; and a palladium plating formed over the first silver layer.
Claim 25
Dependent Claim
74 words
A leadframe for an IC package to mount a semiconductor chip thereon, comprising: a base structure of an alloy of nickel/ferrite, the base structure including an external-lead area and a package area including a bonding area, said bonding area further including a die pad therein for mounting a semiconductor chip thereon; a first silver layer formed over the entire base structure of the leadframe; and a palladium plating formed over the first silver layer.
References Cited (Backward Citations)
US4141029A
Cited
JPS54152867A
Cited
JPS5792854A
Cited
JPS60147148A
Cited
JPS6142941A
Cited
JPS61140160A
Cited
EP0250146A1
Cited
US5138431A
Cited
US5384204A
Cited
JPH04115558A
Cited
US5583379A
Cited
US5650661A
Cited
US5635755A
Cited
US5530283A
Cited
US5675177A
Cited
US5684329A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-03-29 | 2002-09-28 | 2003-03-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-03-29 | 2006-09-28 | 2007-03-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-03-29 | 2010-09-28 | 2011-03-30 | $7700.00 | Window Closed / Lapsed |