# Patent

## Title
Semiconductor photonic package

## Abstract

A method for assembling a semiconductor photonic package device includes bonding a portion of a first surface of a semiconductor die portion to a portion of a carrier portion, bonding a single mode optical ferrule portion to a portion of the first surface of the semiconductor die portion, and disposing a cover plate assembly in contact with the optical ferrule portion and the carrier portion.

## Background
FIELD OF INVENTION
The present invention relates generally to packaging semiconductor dies, and more specifically, to semiconductor dies having both optical input and outputs and electrical inputs and outputs.
DESCRIPTION OF RELATED ART
Semiconductor devices having optical input and outputs have often been used in telecommunications devices. The packaging of such devices has been expensive compared to the packaging of semiconductor devices having electrical inputs and outputs. As nanophotonic semiconductor devices have become more prevalent, efficient and economical packaging and packaging processes are desired.
BRIEF SUMMARY
According to an exemplary embodiment of the present invention, a method for assembling a semiconductor photonic package device includes bonding a portion of a first surface of a semiconductor die portion to a portion of a carrier portion, bonding a single mode optical ferrule portion to a portion of the first surface of the semiconductor die portion, and disposing a cover plate assembly in contact with the optical ferrule portion and the carrier portion.
According to another exemplary embodiment of the present invention, a semiconductor photonic package device includes a carrier portion having a first planar surface and a cavity communicative with the first planar surface, a semiconductor die portion having a first planar surface, the first planar surface of the semiconductor die portion disposed on the first planar surface of the carrier portion, and a single mode optical ferrule portion partially disposed on the first planar surface of the semiconductor die portion, and comprising a cover portion arranged in contact with the first planar surface of the optical ferrule portion.
Additional features and advantages are realized through the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the features, refer to the description and to the drawings.



BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The forgoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1A illustrates a bottom view of a semiconductor die portion.
FIG. 1B illustrates a side view of the semiconductor die portion.
FIG. 1C illustrates a bottom view of a semiconductor die portion and a laser die portion.
FIG. 1D illustrates a side view of the laser die portion bonded to the semiconductor die portion.
FIG. 2A illustrates a bottom view of the resultant structure following the bonding of the semiconductor die portion to a carrier portion.
FIG. 2B illustrates a cut away view along the line 2B of FIG. 2A.
FIG. 3A illustrates a bottom view of the resultant assembly following the deposition of a single mode optical ferrule.
FIG. 3B illustrates a cut away view along the line 3B of FIG. 3A.
FIG. 4A illustrates a top view following the deposition of a heat spreader portion.
FIG. 4B illustrates a cut away view along the line 4B of FIG. 4A.
FIG. 5A illustrates a top view of an exemplary embodiment of an assembly
FIG. 5B illustrates a cut away view along the line 5B of FIG. 5A.
FIG. 6A illustrates a bottom view of an alternate exemplary embodiment of an assembly.
FIG. 6B illustrates a cut away view along the line 6B of FIG. 6A.
FIG. 7A illustrates a bottom view of an alternate exemplary embodiment of an assembly.
FIG. 7B illustrates a cut away view along the line 7B of FIG. 7A.
FIG. 8A illustrates a bottom view of an alternate exemplary embodiment of an assembly.
FIG. 8B illustrates a cut away view along the line 8B of FIG. 8A.



DETAILED DESCRIPTION
The embodiments described herein offer methods and resultant structures that include packaging of micro and nano fabricated semiconductor dies having both optical and electrical inputs and outputs.
FIG. 1A illustrates a bottom view of a semiconductor die portion 102. FIG. 1B illustrates a side view of the semiconductor die portion 102. FIG. 1C illustrates a bottom view of a semiconductor die portion 102 and a laser die portion 104 that is bonded to recess arranged in a first substantially planar surface 101 of the semiconductor die portion 102. The semiconductor die portion 102 includes a second substantially planar surface 103 opposing and arranged substantially parallel to the first surface 101. The semiconductor die portion 102 is a portion of a semiconductor material substrate such as, for example, a silicon or a germanium material. The semiconductor die portion 102 may have a thickness of approximately 50 microns (μm) to 3 millimeters (mm) and preferably between 500 μm and 1 mm. The width and length of the semiconductor die portion 102 are approximately 1 mm to 35 mm and preferably between 5 mm to 10 mm. The first surface 101 may include nanostructures that include, for example, electronic devices and waveguides. The laser die portion 104 includes a substrate that includes a III-V material such as, for example, InP or GaAs with a micro or nanostructure that includes a waveguiding structure and a coherent infrared light generating structure. The coherent infrared light includes a wavelength between 800 nanometers (nm) and 1700 nm and preferably between 1200 nm and 1650 nm. The laser die portion 104 is bonded to a first substantially planar surface 101 of the semiconductor die portion 102 using, for example, a flip-chip bonding process. The flip-chip bonding process forms an electrical connection between conductive contacts on the semiconductor die portion 102 and the laser die portion 104 by arranging conductive solder pads or solder bumps (not shown) on the semiconductor die portion 102 in contact with corresponding conductive solder pads or solder bumps on the laser die portion 104 and affecting the reflow of the solder to result in an electrical and mechanical connection between the corresponding solder on the semiconductor die portion 102 and the laser die portion 104. The flip-chip bonding process may include a flux dispense process when some solders are used. Following the flip-chip bonding process, an underflow and cure of a suitable non-conductive material such as an adhesive that may include, for example an optically transparent adhesive (described below) may be performed to affect a mechanical bond between the semiconductor die portion 102 and the laser die portion 104. The laser die portion 104 and the semiconductor die portion 102 are optically coupled by, for example, a butt coupling or an adiabatic coupling that is defined by waveguide features arranged on the surface 101 of the semiconductor die portion 102 and corresponding features on the laser die portion 104. An optical under fill may be formed between the semiconductor die portion 102 and the laser die portion 104 that improves optical coupling between the semiconductor die portion 102 and the laser die portion 104 and improves the mechanical strength of the arrangement. The FIG. 1D illustrates a side view of the laser die portion 104 bonded to the semiconductor die portion 102.
FIGS. 2A and 2B illustrate, respectively, a bottom view and a cut away view along line 2B of the resultant structure following the bonding of the first surface 101 of the semiconductor die portion 102 to a first substantially planar surface 201 of a carrier portion 202. The semiconductor die portion 102 may be bonded to the carrier portion 202 using a suitable bonding process such as, for example, a flip-chip bonding process similar to the process described above. The carrier portion 202 includes a cut out portion 203 that exposes a portion of the first surface 101 of the semiconductor die portion 102 following the bonding process. The carrier portion 202 includes a cavity 205 that may include a recess or an orifice that is communicative with the first surface 201 of the carrier portion 202 and a second substantially planar surface 207 of the carrier portion 202. The cavity 205 is operative to receive the laser die portion 104 such that the surface 101 of the semiconductor die portion 102 may be arranged substantially parallel to the surface 201 of the carrier portion 202. The carrier portion 202 includes, for example, a polymeric substrate with conductive contacts arranged on the surface 201 that correspond to conductive contacts arranged on the surface 101 of the semiconductor die portion 102. The carrier portion includes conductive contacts 204 that are arranged on the surface 207 of the carrier portion 202. The conductive contacts 204 may be connected to corresponding contacts on, for example, a printed circuit board (not shown) such that the assembly may be connected to the printed circuit board.
FIG. 3A illustrates a bottom view of the resultant assembly following the deposition of a single mode optical ferrule 302 on the surface 101 of the semiconductor die portion 102. In this regard, the optical ferrule 302 contains polymer and single-mode optical waveguides. A single-mode optical waveguide is a waveguide that can guide only one transverse electric mode and one transverse magnetic mode. The optical waveguides may include optical fibers or polymer waveguides. The optical waveguides extend in the ferrule from distal end 301 to the silicon die. The optical waveguides are placed within the ferrule at pre-determined positions at distal end 301 for connection to one optical fiber or an array of optical fibers. For example, an even number of optical waveguides may be positioned at distal end 301 on a plane substantially parallel to 101 with a spacing of 250 um between waveguide centers. In such arrangement, the waveguide position may be compatible with an MT or MPO optical connector standard known by people of skill in the art. The ferrule may include mechanical interfacing structures to align and secure in position at distal end 301 a compatible optical fiber connector with compatible optical and mechanical interface to the said ferrule. An example of such interfacing structure is a pair of holes or pins as in the MT or the MPO optical connector standard know to people of skill in the art. The said optical waveguides interface optically in region 306 to waveguide features arranged on the semiconductor die portion 102. The optical ferrule portion 302 is at least partially arranged in the cut out portion 203 of the carrier portion 202. The optical ferrule 302 includes a waveguide interface portion 306 that may include optical fiber or polymer waveguide that is bonded or connected to a portion of the semiconductor die portion 102 to affect an optical butt coupling or an adiabatic coupling between the semiconductor die portion 102 and the waveguide interface portion 306. The waveguide interface portion 306 may be bonded to the semiconductor die portion 102 by, for example, an optical adhesive disposed therebetween that has a transparency in the infrared wavelength spectrum that the laser die portion 104 operates in. The optical loss in the spectrum for the optical adhesive is below 20 dB/cm and preferably below 5 dB/cm. The ferrule is between approximately 1 mm to 2 mm in height, 2 mm to 6.4 mm in width, and 3 mm to 15 mm in length. The bonding process may include, for example, the deposition of the optical adhesive on a portion of the semiconductor die portion 102 and/or the waveguide interface portion 306. The optical ferrule portion 302 is arranged on the semiconductor die portion 102, and the optical adhesive is cured. The curing may be performed with, for example, ultra violet (UV} light, with thermal treatment, or both. An under fill process may be performed following the curing of the optical adhesive to affect a mechanical connection between the semiconductor die portion 102 and the carrier portion 202 and, in some embodiments, the optical ferrule portion 302 and the semiconductor die portion 102. FIG. 3B illustrates a cut away view along the line 3B (of FIG. 3A).
FIG. 4A illustrates a top view following the deposition of a heat spreader portion 402 on the surface 103 of the semiconductor die portion 102. The heat spreader portion 402 includes a thermally conductive material such as, for example a metallic material. The heat spreader portion 402 may be disposed by applying a thermal interface material (not shown) on a portion of the heat spreader portion 402 and/or the surface 103 of the semiconductor die portion 102. The heat spreader portion 402 is arranged on the surface 103 of the semiconductor die portion 102 and the thermal interface material is cured. In some exemplary embodiments, the heat spreader portion 402 may be mechanically connected to the carrier portion 202 with, for example, an adhesive disposed therebetween. The heat spreader portion 402 is optional and may be included in some exemplary embodiments as desired. FIG. 4B illustrates a cut away view along the line 4B (of FIG. 4A).
FIG. 5A illustrates a top view of an exemplary embodiment of an assembly 500 following the deposition of a cover plate assembly 502 on the surface 401 of the heat spreader portion 402. FIG. 5B illustrates a cut away view along the line 5B (of FIG. 5A). Referring to FIG. 5B, the cover plate assembly 502 may be disposed on the device by, for example, applying an adhesive to the surface 401 of the heat spreader portion 402 and/or a surface of the cover plate assembly 502. An adhesive may also be applied such that the adhesive is disposed between the cover plate assembly 502 and a portion of the optical ferrule 302 and a portion of the carrier portion 202. The cover plate assembly 502 may be fabricated from, for example, a plastic or polymer material, or in some embodiments a thermal conductive material such as a metallic material. The cover plate assembly 502 may include mechanical features such as, for example, latches to provide a mechanical connection between the cover plate assembly 502 and an optical fiber connector. In one embodiment the coverplate include a through-hole in which the heat spreader fits for direct contact between the heat spreader and an external device such as a heat sinking device.
FIG. 6A illustrates a bottom view of an alternate exemplary embodiment of an assembly 600. The assembly 600 is similar to the assembly 500 described above, and includes a bottom cover portion 602 that is arranged over the optical ferrule portion 302. The bottom cover portion 602 may include, for example, a plastic, polymer, or metallic component that is secured to the assembly 600 using, for example, a mechanical or adhesive bonding means. Alternatively, the bottom cover portion 602 may be formed from a polymer that is applied and cured to form a rigid or semi-rigid bottom cover portion 602. A laser cover portion 604 may be arranged to fill or cover a portion of the cavity 205. The laser cover portion 602 may be fabricated using, for example, a similar method as described above regarding the fabrication and deposition of the bottom cover portion 602. FIG. 6B illustrates a cut away view along the line 6B (of FIG. 6A).
FIG. 7A illustrates a bottom view of an alternate exemplary embodiment of an assembly 700. The assembly 700 is similar to the assembly 500 described above, and includes a bottom cover portion 602 that is arranged over the optical ferrule portion 302. In this regard, the cavity 205 does not pass through the semiconductor die portion 205. The FIG. 7B illustrates a cut away view along the line 7B (of FIG. 7A).
FIG. 8A illustrates a bottom view of an alternate exemplary embodiment of an assembly 800. The assembly 800 is similar to the assembly 500 described above, and includes a bottom cover portion 602 that is arranged over the optical ferrule portion 302. FIG. 8B illustrates a cut away view along the line 8B (of FIG. 8A). Referring to FIG. 8B, the assembly 802 does not include a separate heat spreader portion 402 (of FIG. 4). In the illustrated embodiment, the cover plate assembly 802 may contact the surface 103 of the semiconductor die portion 102 and may include a heat spreader portion 804 integrated with the cover plate assembly 802. A thermal interface material (not shown) may disposed between the surface 103 of the semiconductor die portion 102 and the heat spreader portion 804 of the cover plate assembly 802. The cover plate assembly 802 may include mechanical features such as, for example, latches to provide a mechanical connection between the cover plate assembly 502 and an optical fiber connector.
The exemplary embodiments described herein provide a method for fabrication and a resultant device that includes a laser die and a semiconductor die packaged having an optical and an electrical connection in an integrated package. The fabrication methods and components used in fabrication offer an economical and efficient process and an economical resultant device.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof.
The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.
The diagrams depicted herein are just one example. There may be many variations to this diagram or the steps (or operations) described therein without departing from the spirit of the invention. For instance, the steps may be performed in a differing order or steps may be added, deleted or modified. All of these variations are considered a part of the claimed invention.
While the preferred embodiment to the invention had been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the claims which follow. These claims should be construed to maintain the proper protection for the invention first described.

## Claims

1. A semiconductor photonic package device comprising:
a carrier portion having a first planar surface and a cavity communicative with the first planar surface;
a semiconductor die portion having a first planar surface, the first planar surface of the semiconductor die portion disposed on the first planar surface of the carrier portion;
a single mode optical ferrule portion partially disposed on the first planar surface of the semiconductor die portion;
a cover portion arranged in contact with a first planar surface of the optical ferrule portion; and
a laser die portion disposed on the first surface of the semiconductor die portion, wherein the laser die portion is partially arranged in a cavity of the carrier portion;
wherein the cover portion covers the semiconductor die portion, the single mode optical ferrule portion, and the cavity of the carrier portion;
wherein the laser die portion is disposed at a far end of the semiconductor die portion in a length direction such that the laser die portion is not centered on the semiconductor die portion;
wherein the far end of the semiconductor die portion is over the cavity, such that the laser die portion is in the cavity; and
wherein over half of the semiconductor die portion, in the length direction, does not cover the cavity.

2. The device of claim 1, wherein further a heat spreader portion disposed on a second planar surface of the semiconductor die portion, the second planar surface of the semiconductor die portion is substantially parallel to the first planar surface of the semiconductor die portion;
wherein the cover portion further covers the heat spreader portion.

3. The device of claim 1, wherein the cavity of the carrier portion is communicative with the first planar surface of the carrier portion and a second planar surface of the carrier portion, the second planar surface of the carrier portion is arranged in parallel with the first planar surface of the carrier portion.

4. The device of claim 1, wherein the cover portion is arranged in contact with the first planar surface of the carrier portion and in contact with the optical ferrule portion.

5. The device of claim 1, wherein the cavity of the carrier portion is communicative with the first planar surface of the carrier portion and a second planar surface of the carrier portion, the second planar surface of the carrier portion is arranged in parallel with the first planar surface of the carrier portion.

6. The device of claim 1, wherein a heat spreader portion is disposed on a second planar surface of the semiconductor die portion, the second planar surface of the semiconductor die portion is substantially parallel to the first planar surface of the semiconductor die portion.

7. The device of claim 1, wherein about less than one-fourth of the semiconductor die portion, in the length direction, covers the cavity.