US5616953A
Expired / Lapsed
US
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Lead frame surface finish enhancement
Assignee: Micron Technology Inc
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Filing: 1994-09-01
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Granted: 1997-04-01
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Expires: 2014-09-01
Abstract
Abstract An multiple lead semiconductor integrated circuit package incorporating a silicon die wire bonded to a lead frame plated by high purity copper. The die and the lead frame are encapsulated in an epoxy compound with lead fingers from the lead frame extending outside of the encapsulated compound. The high copper plating on the lead frame, which lead frame is not composed of high purity copper, increases the conductivity thereof so as to improve the signal speed for the lead frame. A thinner copper plating on the lead frame can be used without a decrease in signal speed as frequency of the signal is increased.
Inventors
- 👤 Jerrold L. King
- 👤 Syed S. Ahmad
- 👤 Jerry M. Brooks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:16
CPC Classifications
H; H10; H10W; H10W70/00; H10W70/40; H10W70/411; H10W70/415; H10W70/456; H10W70/457; H10W72/00; H10W72/071; H10W72/075; H10W72/30; H10W72/351; H10W72/353; H10W72/354; H10W72/50; H10W72/531; H10W72/536; H10W72/5363; H10W72/5366; H10W72/551; H10W72/552; H10W72/5522; H10W72/59; H10W72/851; H10W72/853; H10W72/865; H10W72/874; H10W72/884; H10W72/90; H10W72/951; H10W72/952; H10W74/00; H10W74/10; H10W90/00; H10W90/701; H10W90/731; H10W90/736; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
108 words
A semiconductor package comprising: a semiconductor die; a lead frame having a conductivity IACS rating of less than or equal to about 3.0%, comprising a frame and a lead finger; a plate, composed of at least 97.5% copper substantially covering the lead frame; means for electrically interconnecting the semiconductor die and the lead frame; and a compound substantially encapsulating the semiconductor die, the lead frame, and the means for electrically interconnecting the semiconductor die and the lead frame, the lead finger having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and uncovered by the compound.
Claim 2
Dependent Claim
108 words
A semiconductor package comprising: a semiconductor die; a lead frame having a conductivity IACS rating of less than or equal to about 3.0%, comprising a frame and a lead finger; a plate, composed of at least 97.5% copper substantially covering the lead frame; means for electrically interconnecting the semiconductor die and the lead frame; and a compound substantially encapsulating the semiconductor die, the lead frame, and the means for electrically interconnecting the semiconductor die and the lead frame, the lead finger having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and uncovered by the compound.
Claim 3
Dependent Claim
21 words
The semiconductor package as defined in claim 1, wherein the plate has a substantially constant thickness of less than 0.0006 inches.
Claim 4
Dependent Claim
21 words
The semiconductor package as defined in claim 2, wherein the plate has a substantially constant thickness of at least 0.00002 inches.
Claim 5
Dependent Claim
19 words
The semiconductor package as defined in claim 1, wherein the plate is composed of at least about 99.9% copper.
Claim 6
Dependent Claim
18 words
The semiconductor package as defined in claim 1, wherein the lead frame is composed of substantially no copper.
Claim 7
Dependent Claim
18 words
The semiconductor package as defined in claim 1, wherein the plate is further composed of about 0.15% phosphorous.
Claim 8
Dependent Claim
26 words
The semiconductor package as defined in claim 1, wherein the lead frame has a magnetic permeability of less than or equal to about 5.15 E-05 Henry/meters.
Claim 9
Dependent Claim
52 words
The semiconductor package as defined in claim 1, further comprising a plurality of lead fingers, each lead finger of said plurality of lead fingers having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and not covered by the compound.
Claim 10
Dependent Claim
16 words
The semiconductor package as defined in claim 8, wherein the semiconductor package is an inline-lead package.
Claim 11
Dependent Claim
16 words
The semiconductor package as defined in claim 9, wherein the semiconductor package is a thin-small-outline package.
Claim 12
Dependent Claim
42 words
The semiconductor package as defined in claim 9, wherein a portion of each said lead finger that is uncovered by the compound is partially covered by both the plate and a lead-tin plating, and is partially covered solely by the lead-tin plating.
Claim 13
Dependent Claim
17 words
The semiconductor package as defined in claim 9, wherein the semiconductor package is a small-outline J-lead package.
Claim 14
Dependent Claim
32 words
The semiconductor package as defined in claim 11, wherein the portion of each said lead finger that is uncovered by the compound is covered by both the plate and a lead-tin plating.
Claim 15
Dependent Claim
25 words
The semiconductor package as defined in claim 1, wherein the means for electrically interconnecting the semiconductor die and the lead frame comprises a bonding wire.
Claim 16
Dependent Claim
24 words
The semiconductor package as defined in claim 1, wherein the means for electrically interconnecting the semiconductor die and the lead frame comprises tab bonding.
Claim 17
Dependent Claim
24 words
The semiconductor package as defined in claim 1, wherein the means for electrically interconnecting the semiconductor die and the lead frame comprises adhesive bonding.
Claim 18
Dependent Claim
16 words
The semiconductor package as defined in claim 1, wherein the semiconductor die is a silicon die.
Claim 19
Dependent Claim
15 words
The semiconductor package as defined in claim 1, wherein the semiconductor die is gallium arsenide.
Claim 20
Dependent Claim
102 words
A semiconductor package comprising: a semiconductor die; a lead frame, composed of substantially no copper, comprising a frame and a lead finger; a plate substantially covering the lead frame and being composed of at least 97.5% copper; means for electrically interconnecting the semiconductor die and the lead frame; and a compound substantially encapsulating the semiconductor die, the lead frame, and the means for electrically interconnecting the semiconductor die and the lead frame, the lead finger having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and uncovered by the compound.
Claim 21
Dependent Claim
102 words
A semiconductor package comprising: a semiconductor die; a lead frame, composed of substantially no copper, comprising a frame and a lead finger; a plate substantially covering the lead frame and being composed of at least 97.5% copper; means for electrically interconnecting the semiconductor die and the lead frame; and a compound substantially encapsulating the semiconductor die, the lead frame, and the means for electrically interconnecting the semiconductor die and the lead frame, the lead finger having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and uncovered by the compound.
Claim 22
Dependent Claim
18 words
The semiconductor package as defined in claim 19, wherein said plate is composed of at least 99.9% copper.
Claim 23
Dependent Claim
25 words
The semiconductor package as defined in claim 19, wherein the lead frame has a conductivity IACS rating of less than or equal to about 3.0%.
Claim 24
Dependent Claim
52 words
A semiconductor package as defined in claim 21, further comprising a plurality of lead fingers, each lead finger of said plurality of lead fingers having an end on the frame inside and covered by the compound and an opposite free end extending from the frame outside and not covered by the compound.
Claim 25
Dependent Claim
51 words
The semiconductor package as defined in claim 22, wherein the semiconductor package is an inline-lead package, and wherein a portion of each said lead finger that is uncovered by the compound is partially covered by both the plate and a lead-tin plating, and is partially covered solely by the lead-tin plating.
Claim 26
Dependent Claim
32 words
The semiconductor package as defined in claim 23, wherein the portion of each said lead finger that is uncovered by the compound is covered by both the plate and a lead-tin plating.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-31 | 2000-09-30 | 2001-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-31 | 2004-09-30 | 2005-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-31 | 2008-09-30 | 2009-04-01 | $7700.00 | Window Closed / Lapsed |