Galvanic signal path isolation in an encapsulated package using a photonic structure

• US 10,444,432 B2
• Filed: 10/31/2017
• Issued: 10/15/2019
• Est. Priority Date: 10/31/2017
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Cook, Benjamin Stassen, Revier, Daniel Lee
• Primary Examiner(s): Petkovsek, Daniel
• Application Number:
  US15/799,740
• Publication Number:
  US 20190131682A1
• Time in Patent Office: 714 Days
• CPC Class Codes: G02B 1/005 made of photonic crystals or photonic band gap materials photonic band-gap structures or photonic lattices in integrated optics G02B6/1225; photonic band-gap structures or photonic lattices in optical fibres G02B6/02295
• CPC Class Codes: G02B 2006/12123 Diode
• CPC Class Codes: G02B 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02B 6/4204 the coupling comprising intermediate optical elements, e.g. lenses, holograms encapsulated active devices H01S5/02208, H01L33/52
• CPC Class Codes: G02B 6/428 containing printed circuit boards [PCB]
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 2223/6677 for antenna, e.g. antenna included within housing of semiconductor device antennas per se H01Q
• CPC Class Codes: H01L 2224/29005 Structure
• CPC Class Codes: H01L 2224/29011 comprising apertures or cavities
• CPC Class Codes: H01L 2224/29199 Material of the matrix
• CPC Class Codes: H01L 2224/29299 Base material
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/45099 Material
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48245 the item being metallic
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4903 Connectors having different sizes, e.g. different diameters
• CPC Class Codes: H01L 2224/73265 : Layer and wire connectors
• CPC Class Codes: H01L 23/16 : Fillings or auxiliary members in containers or encapsulations, e.g. centering rings H01L23/42, H01L23/552 take precedence
• CPC Class Codes: H01L 23/295 : containing a filler H01L23/296 takes precedence
• CPC Class Codes: H01L 23/3107 : the device being completely enclosed
• CPC Class Codes: H01L 23/3121 : a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/3135 : Double encapsulation or coating and encapsulation
• CPC Class Codes: H01L 23/495 : Lead-frames or other flat leads H01L23/498 takes precedence; lead frame interconnections between components H01L23/52
• CPC Class Codes: H01L 23/49513 : having bonding material between chip and die pad
• CPC Class Codes: H01L 23/49537 : Plurality of lead frames mounted in one device
• CPC Class Codes: H01L 23/49541 : Geometry of the lead-frame
• CPC Class Codes: H01L 23/49548 : Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/49575 : Assemblies of semiconductor devices on lead frames
• CPC Class Codes: H01L 23/66 : High-frequency adaptations
• CPC Class Codes: H01L 24/29 : of an individual layer connector
• CPC Class Codes: H01L 24/32 : of an individual layer connector
• CPC Class Codes: H01L 24/48 : of an individual wire connector
• CPC Class Codes: H01L 25/0655 : the devices being arranged next to each other
• 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 2924/00012 : Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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: H01P 1/2005 : Electromagnetic photonic bandgaps [EPB], or photonic bandgaps [PBG]
• CPC Class Codes: H01P 3/10 : Wire waveguides, i.e. with a single solid longitudinal conductor
• CPC Class Codes: H01P 3/123 : with a complex or stepped cross-section, e.g. ridged or grooved waveguides H01P3/14 takes precedence
• CPC Class Codes: H01P 3/16 : Dielectric waveguides, i.e. without a longitudinal conductor
• CPC Class Codes: H01P 5/087 : Transitions to a dielectric waveguide

Abstract

An encapsulated package is provided that includes a pair integrated circuit (IC) die. A radio frequency (RF) circuit on one of the IC die is operable to transmit an RF signal having a selected frequency. An RF circuit on the other IC die is operable to receive the RF signal Encapsulation material encapsulates the IC die. A photonic waveguide couples between the RF transmitter and RF receiver to form galvanic path isolation between the two IC die. The photonic waveguide is formed by a photonic structure within the encapsulation material.

Claims

1. A device, comprising:

a first integrated circuit (IC) die having an electromagnetic transmitter circuit, the electromagnetic transmitter circuit having an output configured to emit an electromagnetic signal;

a second IC die having an electromagnetic receiver circuit, the electromagnetic receiver circuit having an input configured to receive the electromagnetic signal, the second IC die spaced apart from the first IC die;

a leadframe having first and second die attach pads, the first die attach pad separated from the second die attach pad;

a photonic structure including a photonic waveguide coupled between the output of the electromagnetic transmitter circuit and the input of the electromagnetic receiver circuit, a portion of the photonic structure being located between the first IC die and the first die attach pad; and

an encapsulation material encapsulating the first IC die, the second IC die and the photonic waveguide.

2. The device of claim 1, wherein the photonic waveguide includes a photonic bandgap (PBG) structure.

3. The device of claim 2, wherein the PBG structure has a bandgap that includes a frequency of the electromagnetic signal.

4. The device of claim 2, wherein the PBG structure is a multilayer PBG structure, in which layers of the multilayer PBG structure have respective photonic bandgaps with different frequency ranges.

5. The device of claim 4, wherein the respective photonic bandgap of at least one of the layers of the multilayer PBG structure includes a frequency of the electromagnetic signal.

6. The device of claim 4, wherein a first layer of the multilayer PBG structure includes a first matrix of periodically spaced nodes having a first intrinsic property within the encapsulation material, and a second layer of the multilayer PBG structure includes a second matrix of periodically spaced nodes having a second intrinsic property within the encapsulation material, and the encapsulation material has a third intrinsic property, and the first intrinsic property is different from the second intrinsic property and different from the third intrinsic property.

7. The device of claim 1, wherein the photonic structure is a photonic resonant structure having a pass band that includes a frequency of the electromagnetic signal.

8. The device of claim 1, wherein a frequency of the electromagnetic signal is an optical frequency.

9. The device of claim 1, wherein a frequency of the electromagnetic signal is a radio frequency.

10. The device of claim 1, wherein the second IC die is spaced apart from the first IC die by a separation distance that exceeds a voltage breakdown distance.

11. The device of claim 1, wherein the photonic structure includes a matrix of periodically spaced nodes within the encapsulation material, the encapsulation material has a first intrinsic property, and the nodes have a second intrinsic property that is different from the first intrinsic property.

12. The device of claim 11, wherein the nodes have a permittivity that is greater than a permittivity of the encapsulation material.

13. The device of claim 1, wherein the photonic structure includes a diffusion of particles within the encapsulation material, the encapsulation material has a first intrinsic property, and the nodes have a second intrinsic property that is different from the first intrinsic property.

14. The device of claim 1, wherein the photonic waveguide has a rectangular cross section in which a long side of the cross section is twice as long as a short side of the cross section.

15. A method, comprising:

forming a photonic structure including a photonic waveguide;

through a portion of the photonic structure, attaching a first integrated circuit (IC) die having an electromagnetic transmitter to a first die attach pad of a leadframe, the portion of the photonic structure being located between the first IC die and the first die attach pad;

attaching a second IC die having an electromagnetic receiver to a second die attach pad of the leadframe, in which the first die attach pad is separated from the second die attach pad, the first IC die is spaced apart from the second IC die, and the photonic waveguide is coupled between an output of the electromagnetic transmitter and an input of the electromagnetic receiver; and

with an encapsulation material, encapsulating the first IC die, the second IC die and the photonic waveguide.

16. The method of Claim 15, wherein forming the photonic structure comprises forming a matrix of periodically spaced nodes within the encapsulating material, in which the encapsulation material has a first intrinsic property, and the nodes have a second intrinsic property that is different from the first intrinsic property.

17. The method of Claim 15, wherein forming the photonic structure comprises:

forming a first matrix of periodically spaced nodes within the encapsulating material, the first matrix having a first lattice constant; and

forming a second matrix of periodically spaced nodes within the encapsulating material, the second matrix having a second lattice constant.

18. The method of Claim 15, wherein forming the photonic structure comprises diffusing particles within the encapsulating material, in which the encapsulation material has a first intrinsic property, and the particles have a second intrinsic property that is different from the first intrinsic property.