← Back to Patent Explorer
US5409157A Expired / Lapsed US ⏱️ 0.0 years remaining

Composite transversely plastic interconnect for microchip carrier

Assignee: Avago Technologies International Sales Pte Ltd
•
Filing: 1994-03-07
•
Granted: 1995-04-25
•
Expires: 2014-03-07
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A composite transversely plastic interconnect for a microcarrier produces a carrier-to-substrate bond having low electrical resistance and high mechanical strength, significant bond height to mediate TCE mismatch between dissimilar carrier and substrate materials, and sufficient gap between the carrier and the substrate to permit effective post solder cleaning of the interconnect. A contact array consisting of solder balls is placed directly onto either of a carrier or a substrate interconnect surface with a stencil positioned to the chosen interconnect surface. The solder balls may have a selected melting temperature. Additionally, the solder balls may have a metallic coating, such as nickel or copper, or molten solder. The carrier and substrate are joined by mating an interconnect surface of each and applying heat. Solder paste may be applied to one of the interconnect surfaces to add additional height to the joint and compensate for lack of coplanarity between the carrier and the substrate.

Inventors

  • 👤 Voddarahalli K. Nagesh
  • 👤 Daniel J. Miller
  • 👤 Robert A. Schuchard
  • 👤 Jeffrey G. Hargis

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 16:14
CPC Classifications
B; B23; B23K; B23K1/00; B23K1/0008; B23K1/0016; H; H01; H01R; H01R4/00; H01R4/02; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/341; H05K3/3431; H05K3/3436; H10; H10W; H10W90/00; H10W90/701; B23K2101/00; B23K2101/36; B23K2101/40; H05K2201/00; H05K2201/10; H05K2201/10227; H05K2201/10234; H05K2201/10613; H05K2201/10621; H05K2201/10719; H05K2201/10727; H05K2201/10954; H05K2201/10992; H05K2203/00; H05K2203/04; H05K2203/041; H05K2203/0415; H05K2203/0435; H10W72/00; H10W72/01; H10W72/012; H10W72/01221; H10W72/01225; Y; Y02; Y02P; Y02P70/00; Y02P70/50; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802; Y10T428/24826; Y10T428/29; Y10T428/2982; Y10T428/2991

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 123 words
A process for forming a microcontact spacer for providing mechanical and electrical interconnection between a microcarrier having an interconnect surface on which at least one solder pad is formed and a substrate on which at least one complementary solder pad is formed, comprising the steps of: printing solder paste onto said microcarrier solder pad; placing at least one solder ball of selected size onto the microcarrier solder pad; leveling said solder ball by pushing said solder ball into said solder paste from a common plane to compensate for variations in solder ball size; and applying heat to melt said solder paste to bond said solder ball to said microcarrier surface, wherein said solder paste melts at a different temperature than said solder ball.
Claim 2
Dependent Claim 123 words
A process for forming a microcontact spacer for providing mechanical and electrical interconnection between a microcarrier having an interconnect surface on which at least one solder pad is formed and a substrate on which at least one complementary solder pad is formed, comprising the steps of: printing solder paste onto said microcarrier solder pad; placing at least one solder ball of selected size onto the microcarrier solder pad; leveling said solder ball by pushing said solder ball into said solder paste from a common plane to compensate for variations in solder ball size; and applying heat to melt said solder paste to bond said solder ball to said microcarrier surface, wherein said solder paste melts at a different temperature than said solder ball.
Claim 3
Dependent Claim 18 words
The process of claim 1, further comprising the step of: printing solder paste on said substrate solder pad.
Claim 4
Dependent Claim 77 words
The process of claim 1, further comprising the steps of: aligning said microcarrier with said substrate; pressing said microcarrier and said substrate together; forcing the solder ball formed on the microcarrier into electrical and mechanical contact with said substrate solder paste; and heating said microcarrier and substrate in a furnace to reflow said solder paste at said substrate solder pad and complete interconnection therebetween, wherein said solder paste melts am a different temperature than said solder ball.
Claim 5
Dependent Claim 92 words
A process for forming a microcontact spacer for providing mechanical and electrical interconnection between a microcarrier having an interconnect surface on which at least one solder pad is formed and a substrate on which at least one complementary solder Dad is formed, comprising the steps of: printing solder paste onto said microcarrier solder pad; placing at least one solder ball of selected size and having a coating of a barrier metal onto the microcarrier solder pad; leveling said solder ball; and applying heat to bond said solder ball to said microcarrier surface.
Claim 6
Dependent Claim 92 words
A process for forming a microcontact spacer for providing mechanical and electrical interconnection between a microcarrier having an interconnect surface on which at least one solder pad is formed and a substrate on which at least one complementary solder Dad is formed, comprising the steps of: printing solder paste onto said microcarrier solder pad; placing at least one solder ball of selected size and having a coating of a barrier metal onto the microcarrier solder pad; leveling said solder ball; and applying heat to bond said solder ball to said microcarrier surface.
Claim 7
Dependent Claim 18 words
The process of claim 4, wherein said barrier metal is selected from one of placed nickel or copper.
Claim 8
Dependent Claim 17 words
The process of claim 4, wherein said microcontact spacer is first formed on said substrate solder pad.

References Cited (Backward Citations)

JPS63117450A Cited
US4771159A Cited
EP0396484A2 Cited
US5093986A Cited
WO1991020095A1 Cited
US5251806A Cited
US5060844A Cited
US5147084A Cited
US5118027A Cited
JPH05129374A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1998-04-24 1998-10-24 1999-04-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2002-04-24 2002-10-24 2003-04-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2006-04-24 2006-10-24 2007-04-25 $7700.00 Window Closed / Lapsed

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag