Flexible dielectric electronic substrate and method for making same

• US 7,154,046 B2
• Filed: 02/09/2004
• Issued: 12/26/2006
• Est. Priority Date: 06/01/1999
• Status: Expired due to Fees

• Current Assignee: Amerasia International Technology, Inc.
• Original Assignee: Amerasia International Technology, Inc.
• Inventors: Chung, Kevin Kwong-Tai
• Primary Examiner(s): DINH, TUAN T
• Application Number:
  US10/774,882
• Publication Number:
  US 20040159462A1
• Time in Patent Office: 1,051 Days
• Field of Search: 174258-264, 361782-784, 361792-795, 29830-832, 29852-854, 156/306.6, 156/275.1, 156/275.3, 257787-790, 257723-724, 428209-210, 428/901, 428/473.5, 428/195.1
• US Class Current: 174/259
• CPC Class Codes: B32B 2425/00 Cards, e.g. identity cards, credit cards
• CPC Class Codes: B32B 2429/00 Carriers for sound or information
• CPC Class Codes: B32B 37/203 One or more of the layers being plastic
• CPC Class Codes: G06K 19/07743 External electrical contacts
• CPC Class Codes: G06K 19/07745 Mounting details of integrated circuit chips
• CPC Class Codes: G06K 19/07747 at least one of the integrated circuit chips being mounted as a module
• CPC Class Codes: H01L 2224/02379 Fan-out arrangement
• CPC Class Codes: H01L 2224/05001 Internal layers
• CPC Class Codes: H01L 2224/05023 the whole internal layer protruding from the surface
• CPC Class Codes: H01L 2224/05026 the internal layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05124 Aluminium [Al] as principal constituent
• CPC Class Codes: H01L 2224/05144 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05147 Copper [Cu] as principal constituent
• CPC Class Codes: H01L 2224/05155 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05548 Bonding area integrally formed with a redistribution layer on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/05639 Silver [Ag] as principal constituent
• CPC Class Codes: H01L 2224/05644 Gold [Au] as principal constituent
• CPC Class Codes: H01L 2224/05655 Nickel [Ni] as principal constituent
• CPC Class Codes: H01L 2224/05664 Palladium [Pd] as principal constituent
• CPC Class Codes: H01L 2224/05669 Platinum [Pt] as principal constituent
• CPC Class Codes: H01L 2224/0616 : Random array, i.e. array with no symmetry
• CPC Class Codes: H01L 2224/16225 : the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16235 : the bump connector connecting to a via metallisation of the item
• CPC Class Codes: H01L 2224/16237 : the bump connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/32225 : the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/45124 : Aluminium (Al) as principal constituent
• CPC Class Codes: H01L 2224/45144 : Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 : Arched
• CPC Class Codes: H01L 2224/48227 : connecting the wire to a bond pad of the item
• 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 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 2225/0651 : Wire or wire-like electrical connections from device to substrate
• CPC Class Codes: H01L 2225/06517 : Bump or bump-like direct electrical connections from device to substrate
• CPC Class Codes: H01L 2225/0652 : Bump or bump-like direct electrical connections from substrate to substrate
• CPC Class Codes: H01L 2225/06527 : Special adaptation of electrical connections, e.g. rewiring, engineering changes, pressure contacts, layout
• CPC Class Codes: H01L 2225/06541 : Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV] manufacturing via connections per se H01L21/76898
• CPC Class Codes: H01L 2225/06572 : Auxiliary carrier between devices, the carrier having an electrical connection structure
• CPC Class Codes: H01L 2225/06579 : TAB carriers; beam leads
• CPC Class Codes: H01L 2225/06582 : Housing for the assembly, e.g. chip scale package [CSP]
• CPC Class Codes: H01L 2225/06586 : Housing with external bump or bump-like connectors
• CPC Class Codes: H01L 23/055 : the leads having a passage through the base H01L23/057 takes precedence
• CPC Class Codes: H01L 23/49838 : Geometry or layout
• CPC Class Codes: H01L 23/4985 : Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 23/49855 : for flat-cards, e.g. credit cards cards per se G06K19/00
• CPC Class Codes: H01L 23/5387 : Flexible insulating substrates H01L23/5388 takes precedence
• CPC Class Codes: H01L 24/45 : of an individual wire connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 24/73 : Means for bonding being of different types provided for in two or more of groups H01L24/10, H01L24/18, H01L24/26, H01L24/34, H01L24/42, H01L24/50, H01L24/63, H01L24/71
• CPC Class Codes: H01L 25/0657 : Stacked arrangements of devices
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 : the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01014 : Silicon [Si]
• CPC Class Codes: H01L 2924/01028 : Nickel [Ni]
• CPC Class Codes: H01L 2924/01046 : Palladium [Pd]
• CPC Class Codes: H01L 2924/0105 : Tin [Sn]
• CPC Class Codes: H01L 2924/01078 : Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 : Gold [Au]
• CPC Class Codes: H01L 2924/01322 : Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 2924/09701 : Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/12042 : LASER
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15173 : in a single layer of the multilayer substrate
• 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 2924/19041 : being a capacitor
• CPC Class Codes: H01Q 1/2225 : used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
• CPC Class Codes: H01Q 1/36 : Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewithH01Q1/08, H01Q1/14 take precedence
• CPC Class Codes: H01Q 1/38 : formed by a conductive layer on an insulating support patch antennas H01Q9/0407; microstrip dipole antennas H01Q9/065; microstrip slot antennas H01Q13/106; transmission line microstrip antennas H01Q13/206; manufacturing reflecting surfaces using insulating material for supporting the reflecting surface H01Q15/142
• CPC Class Codes: H01Q 23/00 : Antennas with active circuits or circuit elements integrated within them or attached to them
• CPC Class Codes: H01Q 7/00 : Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
• CPC Class Codes: H01Q 7/005 : with variable reactance for tuning the antenna
• CPC Class Codes: H05K 1/0393 : Flexible materials H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups
• CPC Class Codes: H05K 1/113 : Via provided in pad; Pad over filled via
• CPC Class Codes: H05K 1/165 : incorporating printed inductors
• CPC Class Codes: H05K 2201/0355 : Metal foils
• CPC Class Codes: H05K 2201/0394 : Conductor crossing over a hole in the substrate or a gap between two separate substrate parts
• CPC Class Codes: H05K 2201/10674 : Flip chip
• CPC Class Codes: H05K 3/4069 : for via connections in organic insulating substrates
• CPC Class Codes: H05K 3/423 : characterised by electroplating method

Abstract

A molecularly flexible dielectric electronic substrate for receiving an electronic device has a modulus of elasticity less tan about 500,000 psi. The molecularly flexible dielectric substrate comprises one or more sheets or layers of a molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi and having patterned metal foil electrical conductors thereon. The molecularly flexible dielectric adhesive may have a low glass transition temperature and the ability to withstand soldering.

Claims

1. A molecularly flexible dielectric electronic substrate having a modulus of elasticity less than about 500,000 psi, said molecularly flexible dielectric electronic substrate comprising:

a first layer of molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C.;

a metal foil on a first surface of said first layer of molecularly flexible dielectric adhesive, wherein said metal foil is patterned to define a pattern of electrical conductors having a plurality of contact sites for receiving a plurality of contacts of an electronic device; and

a plurality of electrically conductive vias through said first layer of molecularly flexible dielectric adhesive, said plurality of electrically conductive vias being in a pattern for providing electrical connection between ones of said pattern of electrical conductors on the first surface of said first layer of molecularly flexible dielectric adhesive and corresponding contact sites on a second surface of said first layer of molecularly flexible dielectric adhesive opposite the first surface thereof.

2. The molecularly flexible dielectric electronic substrate of claim 1 wherein said plurality of contact sites are in a pattern corresponding to a pattern of contacts of an electronic device.

3. The molecularly flexible dielectric electronic substrate of claim 1 further comprising an electronic device having a plurality of contacts soldered to corresponding ones of the contacts sites of the patterned metal foil on said molecularly flexible dielectric adhesive layer.

4. The molecularly flexible dielectric electronic substrate of claim 1 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 100,000 psi.

5. The molecularly flexible dielectric electronic substrate of claim 1 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 20,000 psi.

6. The molecularly flexible dielectric electronic substrate of claim 1 further comprising a plated electrically conductive layer on at least the contact sites of said metal foil.

7. A molecularly flexible dielectric electronic substrate comprising:

at least one layer of molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and baying the ability to withstand soldering at a temperature of about 220°

C.;

a metal foil on one surface of said layer of molecularly flexible dielectric adhesive, wherein said metal foil is patterned to define a pattern of electrical conductors having a plurality of contact sites for receiving the contacts of an electronic device;

an electronic device having a plurality of contacts soldered to corresponding contacts sites of the patterned metal foil on said molecularly flexible dielectric adhesive layer; and

a protective enclosure surrounding said electronic device and attached at least along its periphery to said molecularly flexible dielectric adhesive layer.

8. A molecularly flexible dielectric electronic substrate comprising:

at least one layer of molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C.;

a metal foil on one surface of said layer of molecularly flexible dielectric adhesive, wherein said metal foil is patterned to define a pattern of electrical conductors having a plurality of contact sites for receiving the contacts of an electronic device;

an electronic device having a plurality of contacts soldered to corresponding contacts sites of the patterned metal foil on said molecularly flexible dielectric adhesive layer; and

an underfill adhesive bonding said electronic device and said molecularly flexible dielectric adhesive layer.

9. The molecularly flexible dielectric electronic substrate of claim 8 wherein said underfill adhesive includes molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi.

10. A molecularly flexible dielectric electronic substrate comprising:

a first layer of molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C.;

a first metal foil on a first exposed surface of said first layer of molecularly flexible dielectric adhesive, wherein said first metal foil is patterned to define a pattern of first electrical conductors having a plurality of contact sites for receiving the contacts of an electronic device;

a second metal foil on a second exposed surface of said first layer of molecularly flexible dielectric adhesive opposing the first surface thereof, wherein said metal foil is patterned to define a pattern of second electrical conductors; and

a plurality of electrically conductive vias through said first layer of molecularly flexible dielectric adhesive, said plurality of electrically conductive vias being in a pattern for providing electrical connection between ones of said first electrical conductors and ones of said second electrical conductors.

11. The molecularly flexible dielectric electronic substrate of claim 10 further comprising:

a second layer of molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C., wherein said second layer of molecularly flexible dielectric adhesive adheres to the second surface of said first layer of molecularly flexible dielectric adhesive with said patterned second metal foil therebetween;

a third metal foil oh an exposed surface of said second layer of molecularly flexible dielectric adhesive, wherein said third metal foil is patterned to define a pattern of third electrical conductors; and

a plurality of second electrically conductive vias through said second layer of molecularly flexible dielectric adhesive, said plurality of second electrically conductive vias being in a pattern for providing electrical connection between ones of said second electrical conductors and ones of said third electrical conductors.

12. The molecularly flexible dielectric electronic substrate of claim 10 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 100,000 psi.

13. The molecularly flexible dielectric electronic substrate of claim 10 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 20,000 psi.

14. The molecularly flexible dielectric electronic substrate of claim 10 in combination with at least one electronic device having a plurality of contacts thereon connected to at least certain ones of the contact sites of said first electrical conductors.

15. The molecularly flexible dielectric electronic substrate of claim 10 wherein said conductive vias are built up of plated metal.

16. The molecularly flexible dielectric electronic substrate of claim 10 further comprising a plated electrically conductive layer an at least the contact sites of said first metal foil.

17. The molecularly flexible dielectric electronic substrate of claim 11 wherein said conductive vias are built up of plated metal.

18. The molecularly flexible dielectric electronic substrate of claim 11 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 100,000 psi.

19. The molecularly flexible dielectric electronic substrate of claim 11 wherein said molecularly flexible dielectric adhesive has a modulus of elasticity less than about 20,000 psi.

20. A method for making a molecularly flexible electronic substrate for receiving an electronic device comprising:

providing a sheet of metal foil;

providing on one a first surface of the sheet of metal foil a first layer of a molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C., the first layer of molecularly flexible dielectric adhesive having a plurality of via openings therein;

building up electrically conductive material on the first surface of the metal foil to fill the plurality of via openings in the first layer of molecularly flexible dielectric adhesive, thereby forming a plurality of electrically conductive vias therein;

wherein the plurality of electrically conductive vias are in a pattern for providing electrical connection between the metal foil and corresponding contact sites on a second surface of the first layer of molecularly flexible dielectric adhesive opposite the first surface thereof;

patterning the metal foil to form a pattern of contacts and conductors electrically connected to the electrically conductive vias in the first molecularly flexible dielectric adhesive layer; and

plating at least one of the electrically conductive vias and the contacts of the patterned metal foil to provide external contacts.

21. The method of claim 20 further comprising:

providing a second metal foil on the second surface of the first layer of molecularly flexible dielectric adhesive opposing the first surface thereof, wherein the second metal foil electrically connects to the plurality of electrically conductive vias in the first molecularly flexible dielectric adhesive layer; and

patterning the second metal foil to form a pattern of contacts and conductors electrically connected to ones of the plurality of electrically conductive vias in the first molecularly flexible dielectric adhesive layer.

22. The method of claim 20 further comprising:

after said patterning the metal foil, providing on the surface of the electrical conductors of the patterned sheet of metal foil not having the first layer of molecularly flexible dielectric adhesive thereon a second layer of a molecularly flexible dielectric adhesive having a modulus of elasticity less than about 500,000 psi, having a glass transition temperature less than about 0°

C., and having the ability to withstand soldering at a temperature of about 220°

C., the at-least second layer of molecularly flexible dielectric adhesive having a plurality of via openings therein; and

building up electrically conductive material on the metal foil to fill the plurality of via openings in the second layer of molecularly flexible dielectric adhesive, thereby forming a plurality of electrically conductive vias therein.

23. The method of claim 20 further comprising electrically connecting contacts of at least one electronic device to corresponding ones of the plurality of electrically conductive vias.