Packaging a substrate with an LED into an interconnect structure only through top side landing pads on the substrate

• US 9,985,004 B2
• Filed: 07/27/2017
• Issued: 05/29/2018
• Est. Priority Date: 01/09/2011
• Status: Active Grant

• Current Assignee: Bridgelux Incorporated
• Original Assignee: Bridgelux Incorporated
• Inventors: West, R. Scott, Tong, Tao, Kwon, Mike, Solomensky, Michael
• Primary Examiner(s): Ho, Anthony
• Application Number:
  US15/660,958
• Publication Number:
  US 20170338209A1
• Time in Patent Office: 306 Days
• Field of Search: 438 28
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• 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 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49113 the connectors connecting different bonding areas on the semiconductor or solid-state body to a common bonding area outside the body, e.g. converging wires
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 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 2924/00014 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: H01L 2924/07811 Extrinsic, i.e. with electrical conductive fillers
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 2933/005 relating to encapsulations
• CPC Class Codes: H01L 2933/0058 relating to optical field-shaping elements
• CPC Class Codes: H01L 2933/0066 relating to arrangements for conducting electric current to or from the semiconductor body
• CPC Class Codes: H01L 2933/0075 relating to heat extraction or cooling elements
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/64 : Heat extraction or cooling elements
• CPC Class Codes: H01L 33/642 : characterized by the shape

Abstract

Standardized photon building blocks are packaged in molded interconnect structures to form a variety of LED array products. No electrical conductors pass between the top and bottom surfaces of the substrate upon which LED dies are mounted. Microdots of highly reflective material are jetted onto the top surface. Landing pads on the top surface of the substrate are attached to contact pads disposed on the underside of a lip of the interconnect structure. In a solder reflow process, the photon building blocks self-align within the interconnect structure. Conductors in the interconnect structure are electrically coupled to the LED dies in the photon building blocks through the contact pads and landing pads. Compression molding is used to form lenses over the LED dies and leaves a flash layer of silicone covering the landing pads. The flash layer laterally above the landing pads is removed by blasting particles at the flash layer.

Claims

1. A device comprising:

a light emitting diode (LED) die;

a substrate with a top surface and a bottom surface, wherein the LED die is disposed adjacent to the top surface of the substrate, and wherein no electrical conductor passes through the substrate from the top surface to the bottom surface;

landing pads disposed on the top surface of the substrate;

an interconnect structure having an opening, wherein the interconnect structure forms a lip around the opening; and

contact pads disposed on an underside of the lip of the interconnect structure, wherein the substrate is electrically connected to the interconnect structure only by the landing pads being attached to the contact pads, and wherein the LED die is electrically coupled to at least one of the contact pads.

2. The device of claim 1, wherein the landing pads are attached to the contact pads by solder bonds, and wherein the substrate is mechanically connected to the interconnect structure only by the solder bonds.

3. The device of claim 1, wherein the landing pads and the contact pads are attached to each other by solder.

4. The device of claim 1, wherein the substrate is connected to the interconnect structure by heating the landing pads such that each of the landing pads aligns with one of the contact pads.

5. The device of claim 1, wherein the interconnect structure has a conductor, and wherein the conductor of the interconnect structure is electrically coupled to the LED die.

6. The device of claim 1, wherein the opening and lip are both circular, wherein a section of the landing pads is disposed laterally inside the opening adjacent to a first contact pad, wherein the LED die is electrically coupled to the first contact pad through the section of the landing pads and through first and second wire bonds, wherein the first and second wire bonds attach to the LED die at corners of the LED die, wherein the LED die is electrically coupled to a second LED die through third and fourth wire bonds, wherein the third and fourth wire bonds attach to the second LED die at corners of the second LED die and attach to the LED die towards the middle of a side of the LED die, and wherein the second LED die is electrically coupled to a second contact pad through fifth and sixth wire bonds that attach to the second LED die towards the middle of a side of the second LED die.

7. The device of claim 6, further comprising:

a lens that is overmolded over the LED die and over the first, second, third, fourth, fifth and sixth wire bonds.

8. The device of claim 1, wherein the interconnect structure is taken from the group consisting of:

a molded interconnect device (MID), an FR-4 epoxy circuit board, and a lead frame structure.

9. A device comprising:

a first light emitting diode (LED) die;

a second LED die;

a substrate with a top surface and a bottom surface, wherein the first LED die and the second LED die are disposed adjacent to the top surface of the substrate, and wherein no electrical conductor passes through the substrate from the top surface to the bottom surface;

landing pads disposed on the top surface of the substrate;

an interconnect structure having a circular opening, wherein the interconnect structure forms a lip around the circular opening; and

contact pads disposed on an underside of the lip of the interconnect structure, wherein the substrate is electrically connected to the interconnect structure only by the landing pads being attached to the contact pads, wherein a section of the landing pads is disposed laterally inside the circular opening but adjacent to a first contact pad, wherein the first LED die is electrically coupled to the first contact pad through the section of the landing pads and through first and second wire bonds, wherein the first and second wire bonds attach to the first LED die at corners of the first LED die, wherein the first LED die is electrically coupled to the second LED die through third and fourth wire bonds, wherein the third and fourth wire bonds attach to the second LED die at corners of the second LED die and attach to the first LED die towards the middle of a side of the first LED die, and wherein the second LED die is electrically coupled to a second contact pad through fifth and sixth wire bonds that attach to the second LED die towards the middle of a side of the second LED die.

10. The device of claim 9, wherein the interconnect structure is taken from the group consisting of:

a molded interconnect device (MID), an FR-4 epoxy circuit board, and a lead frame structure.

11. The device of claim 9, wherein a lens is overmolded over the LED die and over the first, second, third, fourth, fifth and sixth wire bonds.

12. A device comprising:

a light emitting diode (LED) die;

a substrate with a top surface and a bottom surface, wherein the LED die is disposed adjacent to the top surface of the substrate, and wherein no electrical conductor passes through the substrate from the top surface to the bottom surface; and

landing pads disposed on the top surface of the substrate, wherein the landing pads are configured to attach to contact pads disposed on an underside of a lip of an interconnect structure, wherein the lip is formed around an opening in the interconnect structure, wherein the substrate is configured to be electrically coupled to the interconnect structure only by the landing pads being attached to the contact pads such that the LED die is electrically coupled to at least one of the contact pads.

13. The device of claim 12, further comprising:

wire bonds that electrically connect the LED die to the landing pads; and

a lens that is overmolded over the LED die and over the wire bonds.

14. A device comprising:

a light emitting diode (LED) die;

a substrate with a top surface and a bottom surface, wherein the LED die is disposed adjacent to the top surface of the substrate, and wherein no electrical conductor passes through the substrate from the top surface to the bottom surface; and

landing pads disposed on the top surface of the substrate, wherein the device is adapted to connect to an interconnect structure having an opening, wherein a lip is formed around the opening, wherein the landing pads are adapted to attach to contact pads disposed on an underside of the lip, wherein the substrate is adapted to be electrically connected to the interconnect structure only by the landing pads being attached to the contact pads, and wherein the device is adapted to electrically couple the LED die to at least one of the contact pads.

15. The device of claim 14, further comprising:

a lens that is overmolded over the LED die.