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US5833471A Expired / Lapsed US ⏱️ 0.0 years remaining

Hold-down collar for attachment of IC substrates and elastomeric material to PCBS

Assignee: Sun Microsystems Inc
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Filing: 1996-06-11
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Granted: 1998-11-10
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Expires: 2016-06-11
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Abstract

Abstract A land grid array package or a ball grid array package is electrically connected by an elastomeric type layer (containing alternating elements of conductive and non-conductive silicone) to a printed wire board or motherboard. A hold-down collar engages the peripheral edges of the package and snaps into holes in the board in such manner as to create pressure on the elastomeric layer, causing the layer to compress and create through-going electrical paths between exposed lands or conductive elements on the bottom of the package and exposed conductive elements on the wiring board. In one embodiment, solder balls adhere to the exposed conductive elements on the bottom of the package. In this embodiment the collar is initially in two pieces which are fitted together to engage both the top and bottom edges of the substrate.

Inventors

  • 👤 Erich H. Selna

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-05 07:03
CPC Classifications
H; H05; H05K; H05K7/00; H05K7/02; H05K7/12; H05K3/00; H05K3/30; H05K3/32; H05K3/325

Claims Analysis

Total Claims: 15
Claim 1
Independent Claim 191 words
In combination an I-C package having an array of conductive members in a first array on a lower surface of said package and having peripheral top edges, a layer of soft elastomeric material formed with a plurality of conductive and non-conductive vertical elements beneath said package, a printed wire board below said layer having a plurality of conductive lands in a second array on an upper surface of said board, said board underlying said layer and being formed with hold-down collar engaging means, a hold-down collar having in-turned flanges engaging said top edges of said package, legs extending downward relative to said flanges and having board-engaging means cooperable with said collar-engaging means to apply downward force to said flanges and secure said collar to said board, said layer being formed with apertures, said legs passing through said apertures and thereby aligning said layer relative to said first array and said second array, said collar being vertically dimensioned so that when said collar is secured to said board said layer is compressed and conductive elements are exposed to establish electrical circuits between pluralities of said members and corresponding pluralities of said lands.
Claim 2
Dependent Claim 191 words
In combination an I-C package having an array of conductive members in a first array on a lower surface of said package and having peripheral top edges, a layer of soft elastomeric material formed with a plurality of conductive and non-conductive vertical elements beneath said package, a printed wire board below said layer having a plurality of conductive lands in a second array on an upper surface of said board, said board underlying said layer and being formed with hold-down collar engaging means, a hold-down collar having in-turned flanges engaging said top edges of said package, legs extending downward relative to said flanges and having board-engaging means cooperable with said collar-engaging means to apply downward force to said flanges and secure said collar to said board, said layer being formed with apertures, said legs passing through said apertures and thereby aligning said layer relative to said first array and said second array, said collar being vertically dimensioned so that when said collar is secured to said board said layer is compressed and conductive elements are exposed to establish electrical circuits between pluralities of said members and corresponding pluralities of said lands.
Claim 3
Dependent Claim 22 words
The combination of claim 1 in which said package comprises a substrate and encapsulating material on an upper surface of said substrate.
Claim 4
Dependent Claim 30 words
The combination of claim 1 in which said board engaging means comprise prongs on said legs and said collar engaging means comprise apertures in said board to receive said prongs.
Claim 5
Dependent Claim 31 words
The combination of claim 1 in which each said conductive member comprises a second land on the underside of said package and a ball of solder adhered to said second land.
Claim 6
Dependent Claim 23 words
The combination of claim 1 in which said collar comprises a vertical skirt depending from said flanges, said legs depending from said skirt.
Claim 7
Dependent Claim 17 words
The combination of claim 5 in which said package, said layer and said collar are substantially rectangular.
Claim 8
Dependent Claim 226 words
In combination an I-C package having an array of conductive members in a first array on a lower surface and having peripheral top edges, a layer of soft elastomeric material formed with a plurality of conductive and non-conductive vertical elements beneath said package, a printed wire board below said layer having a plurality of conductive lands in a second array on an upper surface of said board, said board underlying said layer and being formed with hold-down collar engaging means, a hold-down collar having first in-turned flanges engaging said top edges of said package, legs extending downward relative to said flanges and having board-engaging means cooperable with said collar-engaging means to apply downward force to said flanges and secure said collar to said board, said collar being vertically dimensioned so that when said collar is secured to said board said layer is compressed and conductive elements are exposed to establish electrical circuits between pluralities of said members and corresponding pluralities of said lands, said collar further comprising second in-turned flanges spaced below said first in-turned flanges a distance substantially equal to the thickness of said package at said top edges, said collar being initially formed in at least two pieces and re-assembled together surrounding said package, said first-mentioned flanges engaging said package above said top edges and said second flanges engaging the bottom of said package.
Claim 9
Dependent Claim 226 words
In combination an I-C package having an array of conductive members in a first array on a lower surface and having peripheral top edges, a layer of soft elastomeric material formed with a plurality of conductive and non-conductive vertical elements beneath said package, a printed wire board below said layer having a plurality of conductive lands in a second array on an upper surface of said board, said board underlying said layer and being formed with hold-down collar engaging means, a hold-down collar having first in-turned flanges engaging said top edges of said package, legs extending downward relative to said flanges and having board-engaging means cooperable with said collar-engaging means to apply downward force to said flanges and secure said collar to said board, said collar being vertically dimensioned so that when said collar is secured to said board said layer is compressed and conductive elements are exposed to establish electrical circuits between pluralities of said members and corresponding pluralities of said lands, said collar further comprising second in-turned flanges spaced below said first in-turned flanges a distance substantially equal to the thickness of said package at said top edges, said collar being initially formed in at least two pieces and re-assembled together surrounding said package, said first-mentioned flanges engaging said package above said top edges and said second flanges engaging the bottom of said package.
Claim 10
Dependent Claim 31 words
The combination of claim 7 in which said second in-turned flanges have a thickness less than the distance between the underside of said package and the upper surface of said layer.
Claim 11
Dependent Claim 63 words
A hold-down collar for attaching an I-C package and an underlying layer of elastomeric material to a printed wire board comprising a first in-turned flange, legs extending downward relative to said flange and printed wire board engaging means on said legs, a second in-turned flange spaced below said first flange, said collar being initially formed in at least two pieces and re-assembled together.
Claim 12
Dependent Claim 63 words
A hold-down collar for attaching an I-C package and an underlying layer of elastomeric material to a printed wire board comprising a first in-turned flange, legs extending downward relative to said flange and printed wire board engaging means on said legs, a second in-turned flange spaced below said first flange, said collar being initially formed in at least two pieces and re-assembled together.
Claim 13
Dependent Claim 28 words
A collar according to claim 9 which further comprises a vertical skirt depending from said flange, said legs depending from said flange, said legs depending from said skirt.
Claim 14
Dependent Claim 20 words
A collar according to claim 9 in which said board engaging means comprises prongs adjacent lower ends of said legs.
Claim 15
Dependent Claim 15 words
A collar according to claim 9 in which said flange is substantially rectangular and horizontal.

References Cited (Backward Citations)

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US4641176A Cited
US4422728A Cited
DE3701310A1 Cited
US5216583A Cited
JPH0498219A Cited
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EP0813356A1 Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 2001-11-09 2002-05-11 2002-11-10 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2005-11-09 2006-05-11 2006-11-10 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2009-11-09 2010-05-11 2010-11-10 $7700.00 Window Closed / Lapsed

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