Optoelectronic package with controlled fiber standoff

• US 6,595,699 B1
• Filed: 08/03/2001
• Issued: 07/22/2003
• Est. Priority Date: 08/03/2001
• Status: Active Grant

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Deane, Peter, Pham, Ken, Nguyen, Luu Thanh, Mazotti, William Paul, Roberts, Bruce Carlton
• Primary Examiner(s): Healy, Brian
• Application Number:
  US09/922,946
• Time in Patent Office: 718 Days
• Field of Search: 385/88, 385/94, 385/89, 385/90, 385/91, 385/92, 385/93, 385/14
• US Class Current: 385/88
• CPC Class Codes: G02B 6/4202 for coupling an active element with fibres without intermediate optical elements, e.g. fibres with plane ends, fibres with shaped ends, bundles
• CPC Class Codes: G02B 6/4212 the intermediate optical element being a coupling medium interposed therebetween, e.g. epoxy resin, refractive index matching material, index grease, matching liquid or gel
• CPC Class Codes: G02B 6/4231 with intermediate elements, e.g. rods and balls, between the elements
• CPC Class Codes: H01L 2224/73207 Bump and wire connectors

Abstract

An optoelectronic component is described that includes a photonic device carried by a substrate. A support structure having a relatively higher portion and a relatively lower portion is formed on or attached to the substrate. In a preferred embodiment, the support structure is a dam structure formed by dispensing a flowable material onto the substrate and hardening the dispensed material. The optoelectronic component further includes one or more optical fibers, with each optical fiber being in optical communication with an active facet on the photonic device. The relatively higher and lower portions of the support structure are arranged to position the optical fiber(s) at a desired standoff distance from the photonic device and to slightly incline the distal tip of each optical fiber relative to the top surface of the photonic device. The described packaging approach can be used in both single fiber and multi-channel devices. In some specific embodiments, the support structure is arranged to engage a fiber termination that holds the optical fiber(s). An optically clear cap may also be provided to cover the active facet of the photonic device. In embodiments where the support structure surrounds the photonic device, the support structure may be used as a containment for the cap. With this arrangement, a flowable clear topping material is dispensed over the photonic device without requiring a traditional molding operation.

Claims

1. An optoelectronic package comprising:

a substrate;

a photonic device carried by the substrate, the photonic device having a top surface that includes an active facet thereon;

an optical support structure attached to the substrate, the optical support structure having a relatively higher portion and a relatively lower portion;

an optically clear cap that covers the active facet of the photonic device, the optically clear cap being contained by the optical support structure; and

an optical fiber in optical communication with the active facet on the photonic device, the optical fiber having a distal tip that is substantially perpendicular to a longitudinal axis of the optical fiber; and

wherein the relatively higher and lower portions of the optical support structure are arranged to position the distal tip of the optical fiber at a desired standoff distance from the photonic device with a small angle of inclination relative to the top surface of the photonic device.

2. An optoelectronic package as recited in claim 1 wherein the optical support structure is a dam structure formed by dispensing a flowable material onto the substrate and hardening the dispensed material, the dam structure having the relatively higher portion and the relatively lower portion.

3. An optoelectronic package as recited in claim 1 wherein the optical support structure is formed by spacers.

4. An optoelectronic package as recited in claim 2 wherein the optically clear cap is formed by dispensing a flowable clear material over the photonic device such that it is contained by the dam structure and hardening the flowable clear material.

5. An optoelectronic package as recited in claim 1 wherein the optical support structure directly contacts a cladding portion of the optical fiber.

6. An optoelectronic package as recited in claim 1 wherein the optical support structure directly contacts a fiber termination that is attached to the optical fiber.

7. An optoelectronic package as recited in claim 2 wherein the dam structure is formed from a plurality of dams.

8. An optoelectronic package as recited in claim 2 wherein the dam structure is formed by dispensing and curing an epoxy based material.

9. An optoelectronic package as recited in claim 1 wherein the substrate has electrically conductive traces thereon that are electrically connected to the photonic device, the optoelectronic package further comprising a semiconductor die in electrical communication with the photonic device through the conductive traces.

10. An optoelectronic package as recited in claim 9 wherein the substrate is formed from a flex material and the die is directly soldered to the substrate, the optoelectronic package further comprising an optical component support block that supports the flex material.

11. An optoelectronic package as recited in claim 6 further comprising a plurality of optical fibers and wherein:

the photonic device has a plurality of facets, each facet being associated with an individual optical fiber; and

the fiber termination holds the plurality of optical fibers.

12. An optoelectronic package as recited in claim 4 wherein the cap is formed from an epoxy material.

13. An optoelectronic package comprising:

a substrate;

a photonic device carried by the substrate, the photonic device having a top surface that includes a plurality of active facets thereon;

a dam structure formed by dispensing a flowable material onto the substrate and hardening the dispensed material, the dam structure having a relatively higher portion and the relatively lower portion;

a plurality of optical fibers, each optical fiber being in optical communication with an associated one of the active facets on the photonic device, the optical fibers each having a longitudinal axis and a distal tip that is substantially perpendicular to the longitudinal axis;

a fiber termination that holds the plurality of optical fibers; and

wherein the relatively higher and lower portions of the optical support structure are arranged to engage the fiber termination to position the distal tips of the optical fibers at a desired standoff distance from the photonic device and to incline the distal tips of the optical fibers a designated small angle relative to the top surface of the photonic device.

14. An optoelectronic package as recited in claim 13 wherein the optically clear cap that covers the active facets of the photonic device is formed by dispensing a flowable clear material over the photonic device such that it is contained by the dam structure and hardening the flowable clear material.

15. An optoelectronic package as recited in claim 14 wherein the dam structure is formed from a plurality of dams.

16. An optoelectronic package as recited in claim 14 wherein the dam structure is formed by dispensing and curing an epoxy based material.

17. An optoelectronic package as recited in claim 14 wherein the cap is formed from an epoxy material.

18. An optoelectronic package comprising:

a substrate formed from a flex material having electrically conductive traces thereon;

an optical component support block that supports the flex material;

a photonic device carried by the substrate, the photonic device having a top surface that includes a plurality of active facets thereon;

a semiconductor die carried by the substrate, the semiconductor die being in electrical communication with the photonic device through the conductive traces;

a dam structure formed by dispensing a flowable material onto the substrate and hardening the dispensed material, the dam structure having a relatively higher portion and the relatively lower portion;

an optically clear cap that covers the active facets of the photonic device, the cap being contained by the dam structure;

a plurality of optical fibers, each optical fiber being in optical communication with an associated one of the active facets on the photonic device, the optical fibers each having a longitudinal axis and a distal tip that is substantially perpendicular to the longitudinal axis;

a fiber termination that holds the plurality of optical fibers; and

wherein the relatively higher and lower portions of the optical support structure are arranged engage the fiber termination to position the distal tips of the optical fibers at a desired standoff distance from the photonic device with a designated small angle of inclination formed between the top surface of the photonic device and the distal tips of the optical fibers.

19. An optoelectronic package as recited in claim 18 wherein the dam structure is formed from a plurality of dams, the dams being formed by dispensing and curing an epoxy based material.

20. An optoelectronic package as recited in claim 18 wherein the cap is formed from an epoxy material.

21. A method of packaging an optoelectronic device comprising:

attaching a photonic device directly or indirectly to a substrate;

forming a dam structure having relatively higher and relatively lower sections on the substrate by dispensing accurate volumes of a flowable material on the base substrate and hardening the dispensed material to form the dam structures;

dispensing an optically clear cap in a region bounded by the dam structure to cover the active facets of the photonic device; and

positioning a fiber termination that carries at least one optical fiber over the photonic device such that the relatively higher and lower portions of the optical support structure engage the fiber termination to position the optical fibers at a desired standoff distance from the photonic device with a small angle of inclination formed between a top surface of the photonic device and a distal tip of each optical fiber.

22. A method as recited in claim 21 wherein the dispensed optical material is selected from the group consisting of an epoxy, an epoxy like material and a silicone gel.

23. A method as recited in claim 22 further comprising electrically connecting the photonic device to substrate by wire bonding and wherein:

the height of the dam structure is sufficiently high to prevent the optical fiber from contacting a bonding wire formed by the wire bonding; and

the cap encapsulates the bonding wire.

24. A method as recited in claim 21 wherein forming the dam structure comprises forming a plurality of dams, wherein a first dam forms the relatively lower portion of the dam structure and a second dam forms the relatively higher portion of the dam structure.

25. A method as recited in claim 21 wherein the dispensed flowable material is an epoxy based material and the hardening is accomplished by curing the epoxy based material.