Method of making flip-chip microwave integrated circuit

• US 5,614,442 A
• Filed: 06/07/1995
• Issued: 03/25/1997
• Est. Priority Date: 08/31/1994
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Tserng, Hua Q.
• Primary Examiner(s): Niebling, John
• Assistant Examiner(s): LEBENTRITT, MICHAEL
• Application Number:
  US08/477,717
• Time in Patent Office: 657 Days
• Field of Search: 437/60, 437/64, 437/209, 437/228, 437/902, 257/276, 257/728, 257/735, 257/579
• US Class Current: 438/122
• CPC Class Codes: H01L 2223/6627 Waveguides, e.g. microstrip line, strip line, coplanar line
• CPC Class Codes: H01L 2223/6644 Packaging aspects of high-frequency amplifiers
• CPC Class Codes: H01L 2223/6683 for monolithic microwave integrated circuit [MMIC]
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/45099 Material
• 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 2224/48464 the other connecting portion not on the bonding area also being a ball bond, i.e. ball-to-ball
• CPC Class Codes: H01L 2224/73257 Bump and wire connectors
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2225/06513 Bump or bump-like direct electrical connections between devices, e.g. flip-chip connection, solder bumps
• CPC Class Codes: H01L 2225/06541 Conductive via connections through the device, e.g. vertical interconnects, through silicon via [TSV]
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H01L 23/4821 Bridge structure with air gap
• CPC Class Codes: H01L 23/5381 Crossover interconnections, e.g. bridge stepovers
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• 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 25/16 : the devices being of types provided for in two or more different main groups of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. forming hybrid circuits
• CPC Class Codes: H01L 25/18 : the devices being of types provided for in two or more different subgroups of the same main group of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N
• 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 2924/01005 : Boron [B]
• CPC Class Codes: H01L 2924/01006 : Carbon [C]
• CPC Class Codes: H01L 2924/01029 : Copper [Cu]
• CPC Class Codes: H01L 2924/01033 : Arsenic [As]
• CPC Class Codes: H01L 2924/01067 : Holmium [Ho]
• 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 2924/10329 : Gallium arsenide [GaAs]
• CPC Class Codes: H01L 2924/1305 : Bipolar Junction Transistor [BJT]
• CPC Class Codes: H01L 2924/1306 : Field-effect transistor [FET]
• CPC Class Codes: H01L 2924/13063 : Metal-Semiconductor Field-Effect Transistor [MESFET]
• CPC Class Codes: H01L 2924/13064 : High Electron Mobility Transistor [HEMT, HFET [heterostructure FET], MODFET]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/1423 : Monolithic Microwave Integrated Circuit [MMIC]
• CPC Class Codes: H01L 2924/19041 : being a capacitor
• CPC Class Codes: H01L 2924/30107 : Inductance
• CPC Class Codes: H01L 2924/3011 : Impedance
• CPC Class Codes: H01L 2924/351 : Thermal stress

Abstract

A flip-chip integrated circuit 1100 having a transistor 1108 formed at a frontside surface of a substrate 1104. An airbridge 1106 may be formed over portions of the transistor wherein a top surface of the airbridge is spaced from the frontside surface by a distance approximately equal to, or greater than, the thickness of the substrate. The circuit may also include a transmission line 1114 at the frontside surface and a heatsink 1102 coupled to the airbridge.

Claims

1. A method of fabricating an integrated circuit, said method comprising the steps of:

(a) forming at least one transistor at a frontside surface of a substrate;

(b) forming at least one transmission line at said frontside surface;

(c) forming an airbridge over portions of said transistor wherein a top surface of said airbridge is spaced from said frontside surface by a distance approximately equal to, or greater than, the thickness of said substrate;

(d) forming a conducting via through said substrate coupling said at least one transistor to a bond pad at said backside surface; and

(e) coupling a heatsink to said airbridge.

2. The method of claim 1, wherein said dielectric material is polyimide.

3. The method of claim 1, further comprising the step of forming a groundplane at said backside surface of said substrate.

4. The method of claim 1, wherein said heatsink comprises a dielectric.

5. The method of claim 4, wherein said dielectric is taken from the group consisting of AIN and BeO.

6. The method of claim 4, wherein said dielectric heatsink is coupled to a metal heatsink.

7. The method of claim 4, wherein said heatsink is metal.