US5390082A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chip carrier with protective coating for circuitized surface
Assignee: International Business Machines Corp
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Filing: 1993-08-03
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Granted: 1995-02-14
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Expires: 2013-08-03
Abstract
Abstract A chip carrier is disclosed which includes a chip carrier substrate and at least one semiconductor chip mounted in a flip chip configuration, via solder balls, on a circuitized surface of the chip carrier substrate. The solder balls are encapsulated in a first encapsulant having a composition which includes an epoxy. In addition, at least a portion of the circuitry on the circuitized surface is encapsulated in a second encapsulant having a composition which includes a urethane, and which composition is chosen so that the second encapsulant exhibits a modulus of elasticity which is equal to or less than about 10,000 psi. As a consequence, the second encapsulant exhibits neither internal cracks, nor interfacial cracks at the interface with the first encapsulant, nor does the second encapsulant delaminate from the circuitized surface, when the chip carrier is thermally cycled.
Inventors
- 👤 Alan W. Chase
- 👤 James W. Wilson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 05:45
CPC Classifications
H; H10; H10W; H10W74/00; H10W74/01; H10W74/012; H10W74/40; H10W74/10; H10W74/111; H10W74/114; H10W74/121; H10W74/15; H10W74/47; H10W72/00; H10W72/01; H10W72/015; H10W72/01515; H10W72/071; H10W72/075; H10W72/50; H10W72/551; H10W72/552; H10W72/5522; H10W72/851; H10W72/853; H10W72/856; H10W72/874; H10W72/884; H10W90/00; H10W90/701; H10W90/721; H10W90/724; H10W90/731; H10W90/734; H10W90/751; H10W90/754
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
158 words
A chip carrier, comprising: a substrate including a surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane and said overall composition is chosen so that said encapsulant exhibits a modulus of elasticity equal to or less than 10,000 psi at 25 degrees C.
Claim 2
Dependent Claim
158 words
A chip carrier, comprising: a substrate including a surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane and said overall composition is chosen so that said encapsulant exhibits a modulus of elasticity equal to or less than 10,000 psi at 25 degrees C.
Claim 3
Dependent Claim
26 words
The chip carrier of claim 1, wherein said encapsulant also covers and thereby encapsulates at least a portion of said upper surface of said semiconductor chip.
Claim 4
Dependent Claim
184 words
A chip carrier, comprising: a substrate including a substrate surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane, said overall composition of said encapsulant being chosen so that, when viewed under a 10 X optical microscope, said encapsulant exhibits no cracks when said chip carrier is subjected to thermal cycling between 0 degrees C. and 100 degrees C., at a frequency of three cycles per hour, for 2,000 cycles.
Claim 5
Dependent Claim
184 words
A chip carrier, comprising: a substrate including a substrate surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane, said overall composition of said encapsulant being chosen so that, when viewed under a 10 X optical microscope, said encapsulant exhibits no cracks when said chip carrier is subjected to thermal cycling between 0 degrees C. and 100 degrees C., at a frequency of three cycles per hour, for 2,000 cycles.
Claim 6
Dependent Claim
26 words
The chip carrier of claim 3, wherein said encapsulant also covers and thereby encapsulates at least a portion of said upper surface of said semiconductor chip.
Claim 7
Dependent Claim
187 words
A chip carrier, comprising: a substrate including a substrate surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane, said overall composition of said encapsulant being chosen so that, when viewed under a 10 X optical microscope, said encapsulant exhibits neither delamination from said substrate, nor cracking, when said chip carrier is thermally cycled from -40 degrees C. to +65 degrees C., at a frequency of one cycle per hour, for ten cycles.
Claim 8
Dependent Claim
187 words
A chip carrier, comprising: a substrate including a substrate surface bearing electrical circuitry which includes at least one substrate contact pad; at least one semiconductor chip mounted face-up on said substrate surface, said semiconductor chip including an upper surface bearing electrical circuitry which includes at least one chip contact pad; at least one wire bond extending from said at least one chip contact pad to said at least one substrate contact pad, which wire bond serves to electrically connect the former contact pad to the latter contact pad; and an encapsulant which covers and thereby encapsulates at least a portion of said electrical circuitry on said substrate surface and at least a portion of said at least one wire bond, Characterized In That said encapsulant has an overall composition which includes a urethane, said overall composition of said encapsulant being chosen so that, when viewed under a 10 X optical microscope, said encapsulant exhibits neither delamination from said substrate, nor cracking, when said chip carrier is thermally cycled from -40 degrees C. to +65 degrees C., at a frequency of one cycle per hour, for ten cycles.
Claim 9
Dependent Claim
26 words
The chip carrier of claim 1, wherein said encapsulant also covers and thereby encapsulates at least a portion of said upper surface of said semiconductor chip.
References Cited (Backward Citations)
US4784872A
Cited
US4623559A
Cited
US4999699A
Cited
US5121190A
Cited
US5173766A
Cited
US5185498A
Cited
US5194027A
Cited
US5243133A
Cited
US5249101A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |