High frequency signal transmission from the surface of a circuit substrate to a flexible interconnect cable

• US 6,867,668 B1
• Filed: 03/26/2002
• Issued: 03/15/2005
• Est. Priority Date: 03/18/2002
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Applied Micro Circuits Corporation (MACOM Technology Solutions Holdings, Inc.)
• Inventors: Dagostino, Carlos Chávez, Perez, Ronald Edward
• Primary Examiner(s): Pascal, Robert
• Assistant Examiner(s): GLENN, KIMBERLY E
• Application Number:
  US10/107,662
• Time in Patent Office: 1,085 Days
• Field of Search: 333/246, 333/238, 333/260, 174/254
• US Class Current: 333/246
• CPC Class Codes: H01L 2223/6627 Waveguides, e.g. microstrip line, strip line, coplanar line
• CPC Class Codes: H01L 2224/05572 the external layer extending out of an opening
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• 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 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• 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 23/4985 Flexible insulating substrates H01L23/49572 and H01L23/49855 take precedence
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• 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 2924/00014 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 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 2924/09701 Low temperature co-fired ceramic [LTCC]
• 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 2924/15313 : being a land array, e.g. LGA
• CPC Class Codes: H01L 2924/1903 : including wave guides
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H05K 1/0219 : Printed shielding conductors for shielding around or between signal conductors, e.g. coplanar or coaxial printed shielding conductors
• CPC Class Codes: H05K 1/0237 : High frequency adaptations H05K1/0216 takes precedence
• CPC Class Codes: H05K 1/147 : at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 2201/10734 : Ball grid array [BGA]; Bump grid array
• CPC Class Codes: H05K 3/222 : Completing of printed circuits by adding non-printed jumper connections printed jumper connections H05K3/4685
• CPC Class Codes: H05K 3/361 : Assembling flexible printed circuits with other printed circuits

Abstract

A high speed flexible interconnect cable includes a number of conductive layers and a number of dielectric layers. Conductive signal traces, located on the conductive layers, combine with the dielectric layers to form one or more high speed electrical transmission line structures. The transmission line structure may be realized as a grounded coplanar waveguide structure, a microstrip structure, a stripline structure, or the like. The cable can be coupled to destination components using a variety of connection techniques, e.g., direct bonding to a circuit substrate, direct soldering to a flip chip, mechanical attachment to a component, or integration with a circuit substrate. The cable can also be terminated with any number of known or standardized connector packages, e.g., SMA, GPPO, or V connectors.

Claims

1. An electronic component carrier substrate comprising:

an exposed device-mounting surface;

a number of conductive substrate traces located on said exposed device-mounting surface, said number of conductive substrate traces forming at least one high-frequency electrical transmission line structure; and

a number of conductive substrate pads located on said exposed device-mounting surface, each corresponding to an end of one of said number of conductive substrate traces; and

each of said number of conductive substrate traces being configured for connection to a corresponding solder ball formed on an electronic device.

2. An electronic component carrier according to claim 1, further including a number of conductive paths through the component carrier substrate, said number of conductive paths for conducting a plurality of low-speed signals.

3. An electronic component carrier according to claim 1, further comprising a ball grid array.

4. An electronic component carrier according to claim 1, wherein said conductive substrate pads are configured to mate with an electrical interconnect cable comprising:

a flexible dielectric layer; and

a flexible conductive layer coupled to said flexible dielectric layer, said flexible conductive layer comprising a number of conductive traces of said high-frequency electrical transmission line structure, each of said conductive traces terminating at an exposed conductive pad located proximate a terminating end of said electrical interconnect cable.

5. An electronic component carrier according to claim 4, wherein said conductive substrate pads and said conductive substrate traces are configured to electrically match said conductive traces of said electrical interconnect cable.

6. A method of forming an electronic assembly comprising:

providing an electronic component carrier substrate comprising;

an exposed device-mounting surface;

a number of conductive substrate traces located an said exposed device-mounting surface, said number of conductive substrate traces forming at least one high-frequency electrical transmission line structure; and

a number of conductive substrate pads located on said exposed device-mounting surface, each corresponding to an end of one of said number of conductive substrate traces;

connecting a number of solder balls of an electronic device to said number of conductive substrate traces;

providing an electrical interconnect cable comprising a flexible dielectric layer and a flexible conductive layer coupled to said flexible dielectric layer, said flexible conductive layer comprising a number of conductive traces of a high-frequency electrical transmission line structure, each of said conductive traces including an exposed conductive pad; and

establishing electrical contact between said exposed conductive pads of said electrical interconnect cable and said conductive substrate pads.

7. A method according to claim 6, wherein establishing electrical contact comprises electrically bonding said exposed conductive pads to said conductive substrate pads.

8. A method according to claim 7, wherein electrically bonding comprises ultrasonically welding said exposed conductive pads to said conductive substrate pads.

9. An electronic assembly comprising:

an electrical interconnect cable comprising;

a flexible dielectric layer;

a flexible conductive layer coupled to said flexible dielectric layer, said flexible conductive layer comprising a number of conductive traces, each of said conductive traces terminating at an exposed conductive pad;

said number of conductive traces and said flexible conductive ground layer forming a high frequency transmission line structure;

a component carrier substrate having an exposed surface and a number of conductive substrate pads located on said exposed surface, said conductive substrate pads being configured in accordance with said high-frequency electrical transmission line structure;

each of said conductive substrate pads being electrically bonded to a corresponding one of said exposed conductive pads to establish electrical signal paths from said component substrate carrier to said electrical interconnect cable;

a number of conductive substrate traces located on said exposed surface and corresponding to said number of conductive substrate pads, said number of conductive substrate traces being configured in accordance with said high-frequency electrical transmission line structure; and

an electronic device having a number of solder balls formed thereon, each of said solder balls connected to a corresponding one of said conductive substrate traces to establish electrical signal paths from said electronic device to said electrical interconnect cable.

10. An electronic assembly according to claim 9 in which the high speed transmission line structure is for carrying signals in the range of 10 Gbps-40 Gbps.

11. An electronic assembly according to claim 9 in which the high speed transmission line structure is for carrying signals above 40 Gbps.

12. An electronic assembly according to claim 9, further comprising an isolating jacket surrounding said flexible dielectric layer and said flexible conductive layer over at least a portion of the length of said electrical interconnect cable.

13. An electronic assembly according to claim 9, wherein said component carrier substrate comprises a ball grid array.