Photonic semiconductor devices in LLC assembly with controlled molding boundary and method for forming same
View Patent ↗Embodiments of a laminate leadless carrier package are presented. The package includes an optoelectronic chip, a substrate supporting the optoelectronic chip, a plurality of conductive slotted vias, a wire bond pad disposed on the top surface of the substrate, a wire bond coupled to the optoelectronic chip and the wire bond pad and an encapsulation covering the optoelectronic chip, the wire bond, and at least a portion of the top surface of the substrate. The slotted vias provide electrical connections between the top conductive layer and the bottom conductive layer. The substrate includes a plurality of conductive and dielectric layers laminated together including a bottom conductive layer, a top conductive layer, and a dielectric layer between the top and bottom conductive layers. The encapsulation is a molding compound, and the molding compound is pulled back from at least one of the slotted vias.
1. A process for manufacturing a plurality of laminate leadless carrier packages, comprising the steps of:
preparing a substrate, wherein preparing said substrate comprises laminating a top conductive layer, a bottom conductive layer, and a dielectric layer between said top and bottom conductive layers together, and wherein said top conductive layer comprises a die attach pad, a wire bond pad, and at least two slotted vias;
applying epoxy adhesive to said die attach pad;
mounting a photonic semiconductor chip on said die attach pad;
wire-bonding said photonic semiconductor chip with said wire bond pad using a wire bond;
temporarily filling said slotted vias with temporary fillers;
molding a molding compound to form an encapsulation covering said photonic semiconductor chip, said wire bond, and at least a portion of said top surface of said substrate;
removing said temporary fillers from the slotted vias; and
dicing said substrate into individual laminate leadless carrier packages.
2. The process of claim 1 , wherein said at least two slotted vias comprise a conductive via providing electrical connection between said top conductive layer and said bottom conductive layer.
3. The process of claim 1 , wherein said at least two slotted vias comprise a slotted via on said top conductive layer.
4. The process of claim 3 , further comprising the step of wherein said at least two slotted vias comprise a slotted via on said top conductive layer for soldering said top conductive layer to mounting pads on a printed circuit board.
5. The process of claim 4 , wherein an active area of said photonic semiconductor chip is arranged perpendicular to said printed circuit board.
6. The process of claim 4 , wherein an active area of said photonic semiconductor chip is arranged parallel to said printed circuit board.
7. The process of claim 1 , further comprising the step of forming a boundary on said top conductive layer between said encapsulation covering and a metal contact.
8. The process of claim 7 , wherein said metal contact comprises a trace on said top conductive layer configured to mechanically and/or electrically connect the photonic semiconductor devices to a mounting board in a side-looker and/or a top-looker orientation.
9. The process of claim 7 , wherein said metal contact comprises at least one of said slotted vias.
10. The process of claim 7 , wherein said boundary is configured to prevent contamination of said molding compound to the integrity of said metal contact.
11. The process of claim 1 , wherein said wire bond pad comprises a portion of said top conductive layer.
12. The process of claim 1 , wherein said molding compound is optically transparent to a band of wavelengths and filters light at particular wavelengths.
13. The process of claim 1 , further comprising the step of molding said top surface of said encapsulation as a flat surface.
14. The process of claim 1 , further comprising the step of molding said top surface of said encapsulation as a lens.
15. The process of claim 14 , wherein said lens selected from a group consisting of a cylindrical lens, a spherical lens, a torroidal lens, an aspherical lens, and a dome-shaped lens.
16. The process of claim 1 , further comprising the step of molding a footing from said encapsulation configured to stabilize said packages when mounted as side-lookers.
17. The process of claim 1 , wherein said photonic semiconductor chip is selected from said group consisting of a laser, a light-emitting-diode, a PN photodiode, a phototransistor, a PIN photodiode, an avalanche photodiode, a single-photon avalanche diode, a charge coupled device, and a silicon photomultiplier.
18. The process of claim 1 , wherein said substrate is selected from said group consisting of thin film ceramic substrates, thick film ceramic substrates, and printed circuit boards.
19. The process of claim 1 , further comprising the step of positioning an optical filter above an active area of said photonic semiconductor chip.
20. The process of claim 1 , wherein said molding further comprises encapsulating said optical filter.
21. A process for manufacturing a laminate leadless carrier package, comprising the steps of:
preparing a substrate, wherein preparing said substrate comprises laminating a top conductive layer, a bottom conductive layer, and a dielectric layer between said top and bottom conductive layers together, and wherein said top conductive layer comprises a die attach pad, a wire bond pad, and at least two slotted vias;
applying epoxy adhesive to said die attach pad;
mounting a photonic semiconductor chip on said die attach pad;
wire-bonding said photonic semiconductor chip with said wire bond pad using a wire bond;
temporarily filling said slotted vias with temporary fillers;
molding a molding compound to form an encapsulation covering said photonic semiconductor chip, said wire bond, and at least a portion of said top surface of said substrate; and
removing said temporary fillers from said slotted vias.