Method of making an integrated circuit microwave interconnect and components

• US 5,453,154 A
• Filed: 11/15/1993
• Issued: 09/26/1995
• Est. Priority Date: 10/21/1991
• Status: Expired due to Term

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Glenn, Michael A., Thomas, Michael E., Saadat, Irfan A.
• Primary Examiner(s): Hearn, Brian E.
• Assistant Examiner(s): GURLEY, LYNNE ANN
• Application Number:
  US08/153,078
• Time in Patent Office: 680 Days
• Field of Search: 437/203, 437/927, 437/246, 437/195, 333/239, 333/248, 333/254, 333/260, 156/630, 156/656
• US Class Current: 216/18
• CPC Class Codes: H01P 3/00 Waveguides; Transmission lines of the waveguide type

Abstract

An integrated circuit microwave interconnect is formed upon a surface by disposing a dielectric layer over the surface and patterning the dielectric layer to form a dielectric region. The dielectric region is then surrounded by a surrounding metal layer. In one embodiment the surface may be a non-metal upon which a metal layer is disposed prior to disposing the dielectric layer. In this embodiment an additional metal layer is disposed adjoining the first metal surface on both sides of the dielectric region after patterning the layer to form the dielectric region. Thus, the two metal layers thereby form the surrounding metal layer around the dielectric region. The microwave interconnect may be formed upon the surface of the substrate, above the surface of the substrate in a floating configuration, or in a trench within the substrate. An opening may be provided through the surrounding metal layer and a second dielectric region, in communication with the first dielectric region by way of the opening, may be formed. The second dielectric region is also surrounded by metal to provide a three-dimensional microwave interconnect. The dielectric material within the surrounding metal layers may be removed by an etching process and a vacuum, partial vacuum, or inert gas may be provided within the surrounding metal layers.

Claims

1. A method of fabricating an integrated circuit microwave interconnect on a substrate, said method comprising the steps of:

(a) forming a trench in the surface of said substrate;

(b) disposing a first layer of metal over at least the inner surface of said trench;

(c) disposing a first layer of dielectric material in said trench over said first metal layer; and

(d) disposing a second layer of metal over said first layer of dielectric material, said second metal layer adjoining said first metal layer on both sides of said first layer of dielectric material to form a surrounding metal layer which surrounds said first layer of dielectric material.

2. The method of fabricating an integrated circuit microwave interconnect of claim 1, comprising the further steps of:

(j) forming a first opening in said first surrounding metal layer;

(k) forming a second patterned region in communication with said first patterned region by way of said opening; and

,

(l) surrounding said second patterned region with a second surrounding metal layer.

3. The method of fabricating an integrated circuit microwave interconnect of claim 2, wherein step (k) comprises the steps of:

(m) disposing a second layer of dielectric material in said first opening and over at least a portion of said first surrounding metal layer; and

,

(n) patterning said second layer of dielectric material to form said second patterned region.

4. The method of fabricating an integrated circuit microwave interconnect of claim 1, comprising the further step of removing said first patterned region from within said first surrounding metal layer.

5. The method of fabricating an integrated circuit microwave interconnect of claim 4, comprising the further steps of:

(o) forming a second opening in at least one of said first and second surrounding metal layers; and

(p) removing at least one of said first and second patterned regions from within at least one of said first and second surrounding metal layers by way of said second opening.

6. The method of fabricating an integrated circuit microwave interconnect of claim 1, comprising the further steps of:

(q) forming a plurality of said microwave interconnect; and

(r) coupling said microwave interconnects to each other.

7. The method of fabricating an integrated circuit microwave interconnect of claim 6, wherein step (r) comprises the step of coupling said microwave interconnects to each other to form a microwave directional coupler.

8. The method of fabricating an integrated circuit microwave interconnect of claim 6, wherein step (r) comprises the step of coupling said microwave interconnects to each other to form a magic tee.

9. The method of fabricating an integrated circuit microwave interconnect of claim 6, wherein step (r) comprises the step of coupling said microwave interconnects to each other to form a microwave circulator.

10. The method of fabricating an integrated circuit microwave interconnect of claim 1, comprising the further steps of:

(s) forming at least two microwave interconnect branches, at least one of said microwave interconnect branches having variable energy propagation characteristics for receiving energy and transmitting said energy in accordance with said variable energy propagation characteristics;

(t) coupling said microwave interconnect branches to said microwave interconnect to permit energy applied to said microwave interconnect to be received and transmitted by said microwave connect branches;

(u) forming energy source means adapted to apply further energy to said interconnect branch having said variable energy propagation characteristics to provide differing energy propagation characteristics between said microwave interconnect branches in accordance with said further energy.

11. A method of fabricating an integrated circuit microwave interconnect on a substrate in accordance with claim 1 wherein step (c) comprises the steps of:

(i) disposing said first layer of said dielectric material in said trench over said first metal layer; and

(ii) removing said dielectric material from the field leaving said dielectric material only in said trench.

12. A method of fabricating an integrated circuit microwave interconnect on a substrate in accordance with claim 1 wherein said substrate comprises a metal substrate, said method comprising the steps of:

(a) forming said trench in the surface of said metal substrate;

(b) disposing said first layer of dielectric material in said trench; and

(c) disposing said layer of metal over said first layer of dielectric material, said second metal layer adjoining said metal substrate on both sides of said first layer of dielectric material to form a surrounding metal structure which surrounds said first layer of dielectric material.

13. A method of fabricating an integrated circuit microwave interconnect on a substrate, said method comprising the steps of:

(a) providing a first layer of metal on a surface of said substrate;

(b) disposing a first layer of dielectric material over said first layer of metal;

(c) patterning said first layer of dielectric material to form a first patterned region;

(d) disposing a second layer of metal over said first patterned region, said second metal layer adjoining said first metal layer on both sides of first patterned region to form a surrounding metal layer which surrounds said first patterned region;

(e) removing said first patterned region from within said first surrounding metal layer;

(f) forming at least two microwave interconnect branches, at least one of said microwave interconnect branches having variable energy propagation characteristics for receiving energy and transmitting said energy in accordance with said variable energy propagation characteristics;

(g) coupling said microwave interconnect branches to said microwave interconnect to permit energy applied to said microwave interconnect to be received and transmitted by said microwave interconnect branches; and

(h) forming energy source means adapted to apply further energy to said interconnect branch having said variable energy propagation characteristics to provide differing energy propagation characteristics between said microwave interconnect branches in accordance with said further energy.