Controlled impedence interposer substrate

• US 5,854,534 A
• Filed: 11/16/1995
• Issued: 12/29/1998
• Est. Priority Date: 08/05/1992
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Roman, James J., Moresco, Larry L., Lee, Michael G., Wang, Wen-chou Vincent, Peters, Michael G., Beilin, Solomon I., Kudzuma, David, Chou, William T., Murase, Teruo, Swamy, Som S.
• Primary Examiner(s): Arroyo, Teresa M.
• Application Number:
  US08/559,369
• Time in Patent Office: 1,139 Days
• Field of Search: 257/723, 257/664, 257/691, 257/700, 257/698, 361/794
• US Class Current: 257/691
• CPC Class Codes: H01L 21/486 Via connections through the substrate with or without pins
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 23/49827 Via connections through the substrates, e.g. pins going through the substrate, coaxial cables H01L23/49822, H01L23/49833, H01L23/4985, H01L23/49861 take 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 23/5385 Assembly of a plurality of insulating substrates
• CPC Class Codes: H01L 23/5387 Flexible insulating substrates H01L23/5388 takes precedence
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• CPC Class Codes: H01L 25/0652 the devices being arranged next and on each other, i.e. mixed assemblies
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA
• CPC Class Codes: H01L 2924/19041 being a capacitor
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H05K 1/144 Stacked arrangements of planar printed circuit boards
• CPC Class Codes: H05K 2201/10378 Interposers

Abstract

An interposer substrate for mounting an integrated circuit chip to a substrate, and method of making the same, are shown. The interposer substrate comprises power supply paths and controlled impedance signal paths that are substantially isolated from each other. Power supply is routed though rigid segments and signals are routed though a thin film flexible connector that runs from the upper surface of the interposer substrate to the lower surface. Bypass capacitance is incorporated into the interposer substrate and connected to the power supply so that it is positioned very close to the integrated circuit chip. The interposer may be fabricated by forming a multilayered thin film structure including the signal paths over a rigid substrate having vias formed therein, removing the central portion of the substrate leaving the two end segments, and folding and joining the end segments such that the vias are connected. In another embodiment of the invention, a separate power plate is provided for carrying the power lines. Portions of the power plate, with a multilayered thin film structure thereon, are cut and folded to form interposers. Methods of making single-chip interposers are also disclosed.

Claims

1. An interposer substrate for coupling an integrated circuit chip to a multichip module substrate, comprising:

a rigid member having a first surface for mounting to said multichip module substrate and a second surface for receiving said integrated circuit chip,

power distribution means for coupling power from said multichip module substrate to said integrated circuit chip, said power distribution means having a plurality of vias formed through said rigid member from said first surface to said second surface and wherein power is routed through said rigid member from said first surface to said second surface; and

,

controlled impedance signal path means for coupling signals from said multichip module substrate to said integrated circuit chip;

wherein said power distribution means and said controlled impedance signal path means are substantially isolated from each other.

2. The interposer of claim 1 further comprising:

a flexible, controlled impedance thin film connector, said thin film connector being mounted at one end thereof on said first surface and at a second end thereof on said second surface,

wherein said signals are routed through said flexible, controlled impedance connector without passing through the body of said rigid member.

3. The interposer of claim 1 comprising an integral bypass capacitor coupled to said power distribution means.

4. The interposer of claim 1 comprising an integral terminal resistor coupled to said signal path means.

5. The interposer of claim 1 wherein said controlled impedance signal path means comprises a strip line.

6. The interposer of claim 2 wherein said rigid member comprises first and second segments, wherein said power distribution means comprises a plurality of vias formed through said first and second segments, and wherein said first and second segments are joined together by interconnecting ends of the vias formed in said first segment with ends of the vias formed in said second segment.

7. The interposer of claim 6 wherein said flexible connector comprises a first conductive layer, a first dielectric layer formed on said first conductive layer, a second conductive layer comprising a plurality of evenly spaced apart, substantially parallel signal lines formed on said first dielectric layer, a second dielectric layer formed on said second conductive layer, and a third conductive layer formed on said second dielectric layer.

8. The interposer of claim 6 wherein said vias are joined by solder bumps.

9. The interposer of claim 6 wherein said vias are joined by wire interconnects.

10. An interposer substrate for coupling an integrated circuit chip to a multichip module substrate, comprising:

a first rigid member having coplanar first and second faces, said first rigid member having a plurality of vias formed therein, said vias providing electrical connection between said first and second faces;

a second rigid member having coplanar first and second faces, said second rigid member having a plurality of vias formed therein, said vias providing electrical connection between said first and second faces;

wherein the first face of said second rigid member is mounted on the first face of said first rigid member, and wherein electrical connection is made between vias in each of said rigid member such that the second face of said first rigid member is electrically coupled to the second face of said second rigid member;

a bypass capacitor formed on the second face of said first rigid member, the plates of said capacitor being electrically connected to at least some of said vias; and

,

a controlled impedance flexible connector containing a plurality of signal paths linking opposite ends thereof, the first end of said flexible connector being attached to said second surface of said first rigid member and the second end of said flexible connector being attached to said second surface of said second rigid member.

11. The interposer of claim 10 further comprising a terminal resistor formed on a face of one of said rigid members and electrically coupled to one of said signal paths.

12. The interposer of claim 10 wherein said flexible connector comprises a thin film multilayered structure comprising plurality of polyimide and metal layers.

13. The interposer of claim 10 wherein said comprises a thin film multilayered structure comprising plurality of benzocyclobutene and metal layers.

14. The interposer of claim 10 wherein said rigid members comprise silicon or ceramic.

15. A power plate for carrying a plurality of IC chips and for coupling signals from the chips to a signal module substrate, the signal module substrate having a plurality of signal lines formed thereon, said power plate comprising:

a substrate having a plurality of first substrate parts at which IC chips may be mounted, a plurality of power lines which route power to said first parts, and a plurality of second substrate parts underlying said first substrate parts, said first parts comprising a plurality of first interconnectors for coupling to integrated circuit chips, second parts having a plurality of second interconnectors for coupled to the signal lines of a signal module; and

a plurality of flexible thin film connectors interconnecting said first and second interconnectors of said first and second substrate parts, respectively.

16. The power plate of claim 15 wherein said substrate comprises a plurality of openings, each opening being adjacent to a first substrate part;

and wherein at least one opening has a thin film connector passes through it.

17. The power plate of claim 15, in which said thin film connectors are integrally formed with said first and second interconnectors.

18. The module of claim 15, in which said power lines are coupled to said chips by vias extending through said first substrate parts.

19. The power plate of claim 15, in which said second substrate parts are formed by cutting said second substrate parts out of said power plate and folding them under said first parts, thereby forming openings in said power plate.

20. The module of claim 15, in which a capacitive layer providing bypass capacitance for said power lines is formed on said substrate between said first interconnectors on said first substrate parts and said chips.

21. A multichip module for integrated circuit chips, comprising:

a) a signal module having a first plurality of signal lines formed thereon for interconnecting said integrated circuit chips;

b) a power plate having a substrate, said substrate having a plurality of power lines for powering said integrated circuit chips; and

c) means for connecting said first signal lines of said signal module to said integrated circuit chips, said connecting means including;

first parts of said substrate having formed thereon a plurality of second signal lines adapted to be connected to integrated circuit chips affixed to said parts;

second substrate parts underlying first parts and having formed thereon a plurality of third signal lines adapted to be connected to said first signal lines formed on said signal module; and

a plurality of flexible, controlled impedance thin film connectors interconnecting said second and third signal lines of said first and second substrate parts, respectively, and

d) wherein said power plate and said signal module are spaced from one another by said second substrate parts.

22. The multichip module of claim 21 wherein said substrate of said power plate comprises a plurality of openings, each opening being adjacent to a first substrate part of said power plate,

wherein at least one said opening has a thin film connector passing through it, and

wherein said multichip module is multilayered by stacking sets of said signal modules and power plates over each other, and spacing said signal modules from one another by substantially interposers extending through said openings in said power plates.

23. The module of claim 22, in which said second substrate parts are formed by cutting said second substrate parts out of said power plate and folding them under said first parts, thereby forming said openings in said power plate.