Methods of making microelectronic connections with liquid conductive elements

• US 6,238,938 B1
• Filed: 05/04/1999
• Issued: 05/29/2001
• Est. Priority Date: 05/02/1996
• Status: Expired due to Term

• Current Assignee: Tessera, Inc. (Adeia, Inc.)
• Original Assignee: Tessera, Inc. (Adeia, Inc.)
• Inventors: Smith, John W.
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): JONES, JOSETTA I
• Application Number:
  US09/305,028
• Time in Patent Office: 756 Days
• Field of Search: 438/10, 438/15, 438/106
• US Class Current: 438/10
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/02333 being a bump
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/13 of an individual bump connector
• CPC Class Codes: H01L 2224/13022 the bump connector being at least partially embedded in the surface
• CPC Class Codes: H01L 2224/13099 Material
• CPC Class Codes: H01L 2224/14181 On opposite sides of the body
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/17051 Bump connectors having different shapes
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2224/8192 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 23/055 the leads having a passage through the base H01L23/057 takes precedence
• CPC Class Codes: H01L 23/48 Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• CPC Class Codes: H01L 23/49816 Spherical bumps on the substrate for external connection, e.g. ball grid arrays [BGA]
• CPC Class Codes: H01L 24/10 Bump connectors bumps on insulating substrates, e.g. chip carriers, H01L23/49816; Manufacturing methods related thereto
• CPC Class Codes: H01L 24/13 : of an individual bump connector
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00013 : Fully indexed content
• CPC Class Codes: H01L 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01013 : Aluminum [Al]
• CPC Class Codes: H01L 2924/01015 : Phosphorus [P]
• CPC Class Codes: H01L 2924/01019 : Potassium [K]
• CPC Class Codes: H01L 2924/01022 : Titanium [Ti]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/0103 : Zinc [Zn]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01039 : Yttrium [Y]
• CPC Class Codes: H01L 2924/01042 : Molybdenum [Mo]
• CPC Class Codes: H01L 2924/01047 : Silver [Ag]
• CPC Class Codes: H01L 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/01074 : Tungsten [W]
• CPC Class Codes: H01L 2924/01075 : Rhenium [Re]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01082 : Lead [Pb]
• CPC Class Codes: H01L 2924/01087 : Francium [Fr]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/014 : Solder alloys
• CPC Class Codes: H01L 2924/15174 : in different layers of the multilayer substrate
• CPC Class Codes: H01L 2924/15311 : being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/16152 : Cap comprising a cavity for hosting the device, e.g. U-shaped cap
• CPC Class Codes: H01L 2924/16195 : Flat cap [not enclosing an internal cavity]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/19105 : in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/3025 : Electromagnetic shielding
• CPC Class Codes: H01L 2924/351 : Thermal stress
• CPC Class Codes: Y10T 29/49126 : Assembling bases
• CPC Class Codes: Y10T 29/49135 : and shaping, e.g., cutting or bending, etc.
• CPC Class Codes: Y10T 29/49144 : by metal fusion
• CPC Class Codes: Y10T 29/49146 : with encapsulating, e.g., potting, etc.

Abstract

A method of making a microelectronic assembly includes providing a first element and a second element with confronting, spaced-apart interior surfaces defining a space therebetween and contacts on the interior surfaces and masses of an electrically conductive material having a melting temperature below about 125° C. in the space so that each mass is disposed between a contact on the first element and a contact on the second element and so that the masses electrically connect the contacts to one another. A flowable liquid material is then introduced around the masses and between the confronting surfaces, and the liquid material is then cured to form a compliant dielectric layer disposed between the confronting surfaces and intimately surrounding each mass.

Claims

1. A method of operating a microelectronic assembly having first and second elements and having masses of a conductive material electrically interconnecting said elements and having a compliant material surrounding the masses, the method including the step of transmitting signals between said elements through said masses, said masses being in an at least partially liquid state at least some times during operation of the assembly, said compliant layer physically containing said liquid masses.

2. A method as claimed in claim 1 wherein said signals are transmitted through said masses while said masses are in said at least partially liquid state.

3. A method as claimed in claim 1 wherein said masses are in a solid state at least some times during operation of the assembly, the method further comprising the step of melting said masses during operation of the assembly.

4. A method as claimed in claim 3 wherein said assembly generates heat during operation, and wherein said masses are melted by the heat generated in said assembly.

5. A method as claimed in claim 3 further comprising the step of freezing said masses.

6. A method as claimed in claim 5 wherein said melting and freezing steps are performed repeatedly.

7. A method as claimed in claim 1 wherein said masses have a melting temperature below about 125°

C.

8. The method of claim 1, wherein first element comprises one or more semiconductor chips.

9. The method of claim 1, wherein said second element comprises a dielectric sheet.