OPTOCOUPLER

• US 20110235974A1
• Filed: 03/23/2010
• Published: 09/29/2011
• Est. Priority Date: 03/23/2010
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Maasi, Gopinath, Tay, Thiam Siew Gary
• Granted Patent: US 8,412,006 B2
• Time in Patent Office: Days
• US Class Current: 385/39
• CPC Class Codes: G02B 6/4274 Electrical aspects G02B6/4263 and G02B6/4265 take precedence
• CPC Class Codes: G02B 6/43 Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 23/66 High-frequency adaptations
• 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 2924/3025 Electromagnetic shielding
• CPC Class Codes: Y10T 29/49204 Contact or terminal manufacturing

Abstract

An optocoupler with optical transmitter and receiver dies attached to a single conductive pad is presented. One of the optical transmitter and receiver dies may be attached directly to the conductive pad, while the other one of the optical transmitter and receiver dies may be attached to the conductive pad by means of three layers of materials comprising an isolation layer sandwiched between two attachment layers. A multi-channel optocoupler with multiple transmitter and/or receiver dies is also presented, in which one of the optical transmitter and receiver dies may be attached directly to the conductive pad. The other optical transmitter or receiver dies may be attached to the conductive pad by means of three layers of materials comprising an isolation layer sandwiched between two attachment layers.

Claims

1. An optocoupler comprising:

a substrate;

a plurality of conductive traces on the substrate;

a conductive pad located on the substrate;

an optical transmitter die, the optical transmitter die operable to emit light;

a first conductive trace of the plurality of conductive traces configured to provide power to the optical transmitter die from a first power supply;

an optical receiver die, the optical receiver die operable to receive light generated by the optical transmitter die; and

a second conductive trace of the plurality of conductive traces configured to provide power to the optical receiver die from a sec- and power supply, the first conductive trace being electrically isolated from the second conductive trace;

wherein one of the optical transmitter and receiver dies is attached directly to the conductive pad, the other one of the optical transmitter and receiver dies is attached to the conductive pad through three layers of materials comprising an isolation layer sandwiched between two attachment layers.

2. The optocoupler of claim 1, further comprising a clear encapsulant that encapsulates the substrate, the conductive pad, the plurality of conductors, the optical transmitter and receiver dies, wherein the clear encapsulant is configured to transfer light from the optical transmitter die to the optical receiver die.

3. The optocoupler of claim 2, wherein the clear encapsulant is coated with a reflective material such that the clear encapsulant functions as a light guide channeling light from the optical transmitter die to the optical receiver die.

4. The optocoupler of claim 1, further comprising:

a clear encapsulant encapsulating at least a portion of the optical transmitter and receiver dies, the clear encapsulant configured to direct light from the optical transmitter die to the optical receiver die; and

an opaque encapsulant encapsulating the clear encapsulant and the substrate.

5. The optocoupler of claim 4, wherein the clear encapsulant has a shape configured to focus light emitted from the optical transmitter die to the optical receiver die.

6. The optocoupler of claim 4, wherein the clear encapsulant is formed using a first molding process and the opaque encapsulant is formed using a second molding process.

7. The optocoupler of claim 1, wherein the optical transmitter die comprises a light emitting diode and the optical receiver die comprises a photo detector.

8. The optocoupler of claim 7, wherein the optical receiver die comprises an amplifier circuit operable to amplify photocurrent induced by light received at the photo detector of the optical receiver die.

9. The optocoupler of claim 1, wherein the three layers of materials are configured to provide electrical isolation, while permitting thermal conductivity between the one of the optical transmitter and receiver dies, and the conductive pad.

10. The optocoupler of claim 1, further comprising at least a second optical transmitter die, wherein the second optical transmitter die is attached to the conductive pad through three layers of materials comprising an isolation layer sandwiched between two attachment layers.

11. The optocoupler of claim 1, further comprising at least a second optical receiver die, the second optical receiver die is attached to the conductive pad through three layers of materials comprising an isolation layer sandwiched between two attachment layers.

12. The optocoupler of claim 1, wherein the conductive pad further comprises an elevated portion, the optical transmitter die is attached to the elevated portion of the conductive pad such that a portion of light emitted from the optical transmitter die is configured to be received directly by the optical receiver die.

13. An optocoupler comprising:

a substrate;

a plurality of conductive traces located on the substrate;

an optical transmitter die, the optical transmitter die operable to emit light, the optical transmitter die configured to be powered from a first power supply through one of the plurality of conductive traces;

an optical receiver die, the optical receiver die operable to receive light emitted by the optical transmitter die, the optical receiver die configured to be powered from a second power supply through one of the plurality of conductive traces; and

a conductive pad located on the substrate, wherein one of the optical transmitter and receiver dies is attached directly to the conductive pad, the other one of the optical transmitter and receiver dies is attached to the conductive pad through three layers of materials comprising an isolation layer sandwiched between two securing layers.

14. The optocoupler of claim 13, further comprising:

a clear encapsulant encapsulating at least a portion of the optical transmitter and receiver dies, the clear encapsulant configured to convey light from the optical transmitter die to the optical receiver die; and

an opaque encapsulant encapsulating the clear encapsulant and the substrate.

15. The optocoupler of claim 14, wherein the clear encapsulant has a shape configured to focus light emitted from the optical transmitter die to the optical receiver die.

16. The optocoupler of claim 13, wherein the optical transmitter die further comprises a light emitting diode and the optical receiver die further comprises a photo detector.

17. The optocoupler of claim 13, further comprising at least a second optical transmitter or receiver die, the second optical transmitter or receiver die attached to the conductive pad through three layers of materials comprising an isolation layer sandwiched between two securing layers.

18. The optocoupler of claim 13, wherein the conductive pad further comprising an elevated portion, the optical transmitter die attached to the elevated portion of the conductive pad and the optical receiver die attached to the conductive pad outside of the elevated portion such that a portion of light emitted from the optical transmitter die operable to be received directly by the optical receiver die.

19. The optocoupler of claim 13, wherein the three layers of materials configured to provide electrical isolation, while permitting thermal conductivity between the one of the optical transmitter and receiver dies and the conductive pad.

20. A method of manufacturing an optocoupler, the method comprising:

providing a substrate with a conductive pad and a plurality of electrically conductive traces on a top surface of the substrate;

forming an insulating material on a portion of a first optical die or on a first portion of the conductive pad, the insulating material forms a first securing layer;

forming an isolation material on the first securing layer, the isolation material forms an isolation layer on the first securing layer;

forming an insulating material on the isolation layer, the insulating material forms a second securing layer such that the isolation layer is sandwiched between the first and second securing layers;

forming an insulating material on a second optical die or on a second portion of the conductive pad;

attaching the first and second optical dies to the first and second portions of the conductive pad respectively;

encapsulating a portion of the conductive pad and the first and second optical dies with a clear encapsulant; and

encapsulating the substrate and the clear encapsulant with an opaque encapsulant;

wherein the first optical die is configured to be powered by a first power supply and the second optical die is configured to be powered by a second power supply through the plurality of electrically conducing traces;

wherein one of the first and second optical dies comprises an optical transmitter die and the other of the first and second optical dies comprises an optical receiver die.