Multi-layer substrates and fabrication processes

• US 6,429,112 B1
• Filed: 03/18/1999
• Issued: 08/06/2002
• Est. Priority Date: 07/07/1994
• Status: Expired due to Term

• Current Assignee: Tessera, Inc. (Adeia Inc.)
• Original Assignee: Tessera, Inc. (Adeia Inc.)
• Inventors: Haba, Belgacem, Smith, John W.
• Primary Examiner(s): Graybill, David E.
• Application Number:
  US09/271,688
• Time in Patent Office: 1,237 Days
• Field of Search: 438/613-617, 438/109, 438/611, 438/FOR.342, 438/FOR.343, 228/180.22
• US Class Current: 438/611
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 23/49811 Additional leads joined to the metallisation on the insulating substrate, e.g. pins, bumps, wires, flat leads H01L23/49827 takes precedence
• CPC Class Codes: H01L 23/5385 Assembly of a plurality of insulating substrates
• 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 2924/09701 Low temperature co-fired ceramic [LTCC]
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H05K 1/0289 having a matrix lay-out, i.e. having selectively interconnectable sets of X-conductors and Y-conductors in different planes
• CPC Class Codes: H05K 2201/0397 Tab
• CPC Class Codes: H05K 2203/1327 Moulding over PCB locally or completely
• CPC Class Codes: H05K 3/4084 by deforming at least one of the conductive layers
• CPC Class Codes: H05K 3/4092 Integral conductive tabs, i.e. conductive parts partly detached from the substrate
• CPC Class Codes: H05K 3/4614 the electrical connections between the circuit boards being made during lamination
• CPC Class Codes: H05K 3/462 characterized by laminating only or mainly similar double-sided circuit boards

Abstract

Multilayer components such as circuit panels are fabricated by connecting conductive features such as traces one two or more superposed substrates using leads extending through an intermediate dielectric layer. The leads can be closely spaced to provide a high density vertical interconnection, and can be selectively connected to provide customization of the structure.

Claims

1. A method of making a multilayer circuit panel comprising:

(a) providing a first substrate and a second substrate, each such substrate including at least one dielectric layer and electrically conductive features including at least one of;

(i) one or more traces extending in one or more horizontal directions along the at least one dielectric layer; and

(ii) one or more electrically conductive planes extending in horizontal directions along the at least one dielectric layer;

(b) providing a first set of elongated, vertically-extensive leads extending at least partially between said first and second substrates and electrically connected between the electrically conductive features on said first and second substrates; and

(c) injecting a flowable material around said leads and curing said flowable material to form a first intermediate layer between said substrates surrounding said first set of leads,

said step of providing said first set of said elongated vertically-extensive leads includes connecting said elongated leads between said first and second substrates while said elongated leads are in a horizontal disposition and moving said substrates away from one another so as to bend said leads to a vertically extensive disposition.

2. A method as claimed in claim 1, wherein connecting said leads between said substrates includes providing said leads on a surface of one of said substrates, each such lead having a fixed end permanently attached to such substrate and a free end movable with respect to such substrate and juxtaposing said substrates with one another so as to connect the free ends of the leads to the other one of said substrates.

3. A method as claimed in claim 1 wherein connecting said leads between said substrates includes providing partial leads on surfaces of both of said substrates, each such partial lead having a fixed end permanently attached to the associated substrate, each such partial lead also having a free end movable with respect to the associated substrate, and juxtaposing said substrates with one another so as to connect the free ends of the partial leads to one another.

7. A method as claimed in claim 1 wherein providing said first set of leads includes connecting said first set of leads between said first substrate and a third substrate disposed between said first and second substrates, and wherein injecting said flowable material includes injecting the flowable material between the first and third substrates, the method further comprising connecting a second set of leads between said third substrate and said second substrate and injecting a flowable material between said second and third substrates to form a second intermediate layer surrounding said second set of leads.

8. A method as claimed in claim 7 wherein at least portions of said first and second sets of leads are provided on oppositely-directed faces of said third substrate.

4. A method of making a multilayer circuit panel comprising:

(a) providing a first substrate and a second substrate, each such substrate including at least one dielectric layer and electrically conductive features including at least one of;

(i) one or more traces extending in one or more horizontal directions along the at least one dielectric layer; and

(ii) one or more electrically conductive planes extending in horizontal directions along the at least one dielectric layer;

(b) providing a first set of elongated, vertically-extensive leads extending at least partially between said first and second substrates and electrically connected between the electrically conductive features on said first and second substrates; and

(c) injecting a flowable material around said leads and curing said flowable material to form a first intermediate layer between said substrates surrounding said first set of leads,

wherein providing first set of said vertically-extensive leads includes connecting said leads between said first and second substrates while said leads are in a horizontal disposition and moving said substrates away from one another so as to bend said leads to a vertically extensive disposition,

wherein connecting said leads between said substrates includes providing partial leads on surfaces of both of said substrates, each such partial lead having a fixed end permanently attached to the associated substrate, each such partial lead also having a free end movable with respect to the associated substrate, and juxtaposing said substrates with one another so as to connect the free ends of the partial leads to one another, and

wherein said partial leads on said first substrate extend in a first horizontal direction and said partial leads on said second substrate extend in a second horizontal direction transverse to said first horizontal direction, whereby the connected partial leads form generally L-shaped composite leads.

5. A method as claimed in claim 4 wherein said conductive features of said first substrate include a nearest layer of traces at or adjacent the surface of said first substrate bearing said partial leads, at least some of said traces in said nearest layer adjacent said leads extending generally in an x horizontal direction, said partial leads on said first substrate extending generally in said x horizontal direction.

6. A method as claimed in claim 5 wherein said conductive features of said second substrate include a nearest layer of traces at or adjacent the surface of said second substrate bearing said partial leads of said second substrate, at least some of said traces in said nearest layer of said second substrate adjacent such partial leads extending generally in a y horizontal direction perpendicular to said x horizontal direction, said partial leads on said second substrate extending generally in said y horizontal direction.

9. A method of making a multilayer circuit panel comprising:

(a) providing a first substrate and a second substrate, each such substrate including at least one dielectric layer and electrically conductive features including at least one of;

(i) one or more traces extending in one or more horizontal directions along the at least one dielectric layer; and

(ii) one or more electrically conductive planes extending in horizontal directions along the at least one dielectric layer;

(b) providing a first set of elongated, vertically-extensive leads extending at least partially between said first and second substrates and electrically connected between the electrically conductive features on said first and second substrates; and

(c) injecting a flowable material around said leads and curing said flowable material to form a first intermediate layer between said substrates surrounding said first set of leads,

the method further comprising repeating the aforesaid steps, using the multilayer circuit panel formed in the first performance of such steps as a substrate in the second performance of such steps, so as to form a final multilayer panel including at least two layers of leads extending through at least two intermediate layers.

10. A method of providing electrical connections between substrates having electrically conductive features thereon, the method comprising:

(a) providing a plurality of substrates and a first set of leads in a generally horizontal disposition on a surface of one of said substrates, each such lead having a fixed end permanently attached to one of said substrates and a free end movable with respect to such substrate;

(b) electrically connecting the leads between conductive features on different ones of said substrates by making bonds at free ends of the leads;

(c) moving the substrates away from one another so as to deform the leads to a vertically-extensive disposition; and

(d) selectively controlling at least one of steps (a) and (b) so as to selectively control the connections between conductive features on different substrates provided by said leads.

11. A method as claimed in claim 10 wherein said selectively controlling includes selectively controlling said bond-making step.

12. A method as claimed in claim 11 wherein said bond-making step includes activating a bonding material at the free ends of the leads, said selectively controlling including selectively providing the bonding material at less than all of said free ends.

13. A method as claimed in claim 12 wherein said bonding material is selected from the group consisting of solders, eutectic bonding materials, diffusion bonding materials and conductive polymeric compositions.

14. A method as claimed in claim 10 wherein said selectively controlling includes selectively providing connections between the fixed ends of said leads and conductive features on the substrate carrying such leads.

15. A method as claimed in claim 10 wherein said selectively controlling includes selectively providing said leads.

16. A method of providing electrical connections between a first element and a second element comprising:

(a) providing said first and second element with elongated partial leads extending in horizontal directions along lead-bearing surfaces of the elements, the partial leads on each element having fixed ends attached to that element and free ends movable with respect to that element, the partial leads on said first element being elongated in a first horizontal direction, the partial leads on the second element being elongated in a second horizontal direction transverse to the first horizontal direction;

(b) juxtaposing the lead-bearing surfaces of the first and second element so that the tip ends of the partial leads on the first element are engaged with the free ends of the partial leads on the second element, and bonding at least some of the engaged partial tip ends to one another to thereby form composite, crooked leads extending between the first and second elements.

17. A method as claimed in claim 16 further comprising moving said first and second elements away from one another to thereby bend said crooked leads to a vertically-extensive disposition.

18. A method as claimed in claim 17 wherein, prior to moving said elements, the free ends of the partial leads are releasably attached to said elements.

19. A method as claimed in claim 16 further comprising selectively controlling said bonding so that less than all of said partial leads on said first element are connected to partial leads on said second element.