Patent US6239484B1 successfully refreshed from Google Patents.
US6239484B1
Expired / Lapsed
US
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Underfill of chip-under-chip semiconductor modules
Assignee: International Business Machines Corp
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Filing: 1999-06-09
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Granted: 2001-05-29
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Expires: 2019-06-09
Abstract
Abstract A chip-under-chip module and a substrate for making the module. The module comprises a first larger chip, a second smaller chip attached to the underside of the first chip, a substrate having a top surface to which the first chip is mounted, a cavity into which the second chip fits when the first chip is mounted on the top surface, and an access channel connecting the cavity to the top surface. Underfill is disposed under the first chip between the first chip and the substrate, between the first and second chips, within the cavity, and within the access channel. A process for manufacture of such a module comprises the steps of forming the substrate having the cavity and access channel in the substrate, connecting the first chip to the substrate, and dispensing underfill through the access channel.
Inventors
- 👤 Kevin A. Dore
- 👤 David L. Edwards
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 16:38
CPC Classifications
H; H10; H10W; H10W74/00; H10W74/01; H10W74/012; H10W70/00; H10W70/60; H10W70/67; H10W70/68; H10W72/00; H10W72/30; H10W74/10; H10W74/15; H10W90/00; H10W70/682; H10W72/071; H10W72/072; H10W72/073; H10W72/851; H10W72/853; H10W72/856; H10W90/20; H10W90/291; H10W90/701; H10W90/721; H10W90/722; H10W90/724; H10W90/731; H10W90/734
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
117 words
A chip-under-chip module comprising: a larger first chip; a smaller second chip mounted under said first chip; a substrate having a top surface to which said first chip is mounted, said substrate having a cavity into which said second chip fits when said first chip is mounted on said top surface, and an underfill access channel connecting said cavity to an access point not underlying said first chip; and underfill disposed under said first chip in said cavity, between said first chip and said substrate, between said first and second chip, and in said channel, said channel aiding the flow of underfill to distribute underfill around said second chip and between said first and said second chips.
Claim 2
Dependent Claim
117 words
A chip-under-chip module comprising: a larger first chip; a smaller second chip mounted under said first chip; a substrate having a top surface to which said first chip is mounted, said substrate having a cavity into which said second chip fits when said first chip is mounted on said top surface, and an underfill access channel connecting said cavity to an access point not underlying said first chip; and underfill disposed under said first chip in said cavity, between said first chip and said substrate, between said first and second chip, and in said channel, said channel aiding the flow of underfill to distribute underfill around said second chip and between said first and said second chips.
Claim 3
Dependent Claim
17 words
The module of claim 1 wherein said underfill is one of a heat-curable and a radiation-curable resin.
Claim 4
Dependent Claim
17 words
The module of claim 1 wherein said channel and said cavity have equivalent depths within said substrate.
Claim 5
Dependent Claim
17 words
The module of claim 1 wherein said channel and said cavity have different depths within said substrate.
Claim 6
Dependent Claim
23 words
The module of claim 1 wherein said channel has a floor and a curved end wall connecting said floor to said top surface.
Claim 7
Dependent Claim
23 words
The module of claim 1 wherein said channel has a sloping depth from said top surface to a maximum depth at said cavity.
Claim 8
Dependent Claim
56 words
The module of claim 1 wherein said underfill forms a fillet between an edge of said first chip and said substrate top surface at a first distance from said first chip and in which said channel extends from said first chip a second distance that is essentially the same as or greater than said first distance.
Claim 9
Dependent Claim
15 words
The module of claim 7 wherein said channel extends to an edge of said substrate.
Claim 10
Dependent Claim
24 words
The module of claim 1 further comprising solder balls connecting said first chip to said second chip and said first chip to said substrate.
Claim 11
Dependent Claim
14 words
The module of claim 9 wherein said solder balls are controlled collapse chip connections.
Claim 12
Dependent Claim
15 words
The module of claim 10 wherein all of said connections have a same melting temperature.
Claim 13
Dependent Claim
20 words
The module of claim 10 wherein some of said connections have a different melting temperature than others of said connections.
Claim 14
Dependent Claim
27 words
The module of claim 1 wherein said substrate further comprises a recess in which said first chip is disposed and said channel is located within said recess.
Claim 15
Dependent Claim
20 words
The module of claim 1 formed by a process of dispensing said underfill into said cavity through said access channel.
Claim 16
Dependent Claim
134 words
A substrate for receiving a stacked chip subassembly comprising a first chip having a first area on which there is mounted a second chip having a second area smaller than said first area, the substrate comprising: (a) a surface; (b) a cavity extending to said surface, dimensioned to receive the second chip but not the first chip, and (c) an underfill access channel extending from said cavity to an access point on said substrate surface located at a distance from said cavity such that when said first chip is placed on said substrate with said second chip contained in said cavity, the access point is not covered by the first chip, said access channel aiding the flow of underfill to distribute underfill around said second chip and between said first and said second chips.
Claim 17
Dependent Claim
134 words
A substrate for receiving a stacked chip subassembly comprising a first chip having a first area on which there is mounted a second chip having a second area smaller than said first area, the substrate comprising: (a) a surface; (b) a cavity extending to said surface, dimensioned to receive the second chip but not the first chip, and (c) an underfill access channel extending from said cavity to an access point on said substrate surface located at a distance from said cavity such that when said first chip is placed on said substrate with said second chip contained in said cavity, the access point is not covered by the first chip, said access channel aiding the flow of underfill to distribute underfill around said second chip and between said first and said second chips.
Claim 18
Dependent Claim
24 words
The substrate according to claim 15 wherein said channel has a floor angled relative to the substrate surface with increasing depth approaching said cavity.
Claim 19
Dependent Claim
12 words
The substrate of claim 15 wherein said substrate is a ceramic substrate.
Claim 20
Dependent Claim
12 words
The substrate of claim 15 wherein said substrate is an organic substrate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-05-28 | 2004-11-27 | 2005-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-05-28 | 2008-11-27 | 2009-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-05-28 | 2012-11-27 | 2013-05-29 | $7700.00 | Window Closed / Lapsed |