Packaging photon building blocks having only top side connections in a molded interconnect structure

• US 9,130,139 B2
• Filed: 01/16/2014
• Issued: 09/08/2015
• 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
• Primary Examiner(s): Ho, Anthony
• Application Number:
  US14/156,617
• Publication Number:
  US 20140131747A1
• Time in Patent Office: 600 Days
• Field of Search: 438/22, 257/79, 257/88
• US Class Current: 1/1
• 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. An LED system, comprising:

a substrate with a top surface;

an array of LED dies mounted on the top surface of the substrate, wherein electrical connections to the LED dies are made only through a plurality of top-side contacts disposed on the top surface of the substrate; and

a compression molded lens formed over at least one of the LED dies, the compression molded lens made of a material, wherein the material is disposed over substantially all of the top surface of the substrate except for over the plurality of top-side contacts.

2. The LED system of claim 1, wherein the substrate is a portion of a closed board that has been detached from the closed board.

3. The LED system of claim 1, further comprising:

a plurality of solder connections formed on the plurality of top-side contacts; and

a plurality of leads coupled to the plurality of solder connections.

4. The LED system of claim 1, wherein the substrate is rectangular and has four upper edges, and wherein the material extends to each of the four upper edges of the substrate.

5. The LED system of claim 1, wherein the substrate has a bottom surface, and wherein the substrate has no electrical contact on the bottom surface.

6. The LED system of claim 1, wherein the substrate is rectangular and has four upper edges, and wherein there are less than three millimeters between one of the four upper edges of the substrate and an edge of the compression molded lens.

7. An LED system, comprising:

a substrate with an array of LED dies disposed on a top surface of the substrate, wherein electrical connections to the array of LED dies are made through a plurality of top-side contacts disposed only on the top surface of the substrate; and

a molded lens formed over at least one of the LED dies, wherein the molded lens is made of a material disposed over substantially all of the top surface of the substrate except for over the plurality of top-side contacts, wherein the material is selectively removed from areas above the plurality of top-side contacts.

8. The LED system of claim 7, wherein the substrate is a portion of a closed board that has been detached from the closed board.

9. The LED system of claim 7, further comprising:

a plurality of solder connections formed on the plurality of top-side contacts; and

a plurality of leads coupled to the plurality of solder connections.

10. The LED system of claim 7, wherein the substrate is rectangular and has four upper edges, and wherein the material extends to each of the four upper edges of the substrate.

11. The LED system of claim 7, wherein the substrate has a bottom surface, and wherein the substrate has no electrical contact on the bottom surface.

12. The LED system of claim 7, wherein the substrate is rectangular and has four upper edges, and wherein there are less than three millimeters between one of the four upper edges of the substrate and an edge of the molded lens.

13. An LED system, comprising:

a substrate with an array of LED dies disposed on a top surface of the substrate, wherein electrical connections to the array of LED dies are made through a plurality of top-side contacts disposed only on the to surface of the substrate, wherein the substrate is rectangular and has four sides, and wherein a cut pattern is present on each of the four sides; and

a molded lens formed over at least one of the LED dies, wherein the molded lens is made of a material disposed over substantially all of the top surface of the substrate except for over the plurality of top-side contacts, wherein the material is selectively removed from areas above the plurality of top-side contacts.

14. The LED system of claim 13, wherein the cut pattern is a v-cut pattern with a thin middle portion that is rougher than cut portions above and below the thin middle portion.

15. The LED system of claim 13, wherein the cut pattern is a saw-blade cut pattern.

16. The LED system of claim 13, wherein the cut pattern is a laser-machined cut pattern.

17. The LED system of claim 13, wherein the cut pattern is a punch-cut pattern.

18. An LED system, comprising:

a substrate with a to surface, wherein the substrate is rectangular and has four sides, and wherein a cut pattern is present on each of the four sides;

an array of LED dies, wherein electrical connections to the LED dies are made only through a plurality of top-side contacts disposed on the top surface of the substrate; and

a compression molded lens formed over at least one of the LED dies, the compression molded lens made of a material, wherein the material is disposed over substantially all of the to surface of the substrate except for over the plurality of top-side contacts.

19. The LED system of claim 18, wherein the cut pattern is a v-cut pattern with a thin middle portion that is rougher than cut portions above and below the thin middle portion.

20. The LED system of claim 18, wherein the cut pattern is a saw-blade cut pattern.