Packaging technique for the fabrication of polarized light emitting diodes

• US 7,518,159 B2
• Filed: 06/21/2006
• Issued: 04/14/2009
• Est. Priority Date: 06/21/2005
• Status: Expired due to Fees

• Current Assignee: Japan Science And Technology Agency
• Original Assignee: Japan Science And Technology Agency, Regents of the University of California (University of California)
• Inventors: DenBaars, Steven P., Nakamura, Shuji, Masui, Hisashi
• Primary Examiner(s): VU, HUNG K
• Application Number:
  US11/472,186
• Publication Number:
  US 20060284206A1
• Time in Patent Office: 1,028 Days
• Field of Search: 257 79-103, 257/E33.003, 257/E33.006, 438/22, 438/24, 438/25, 438/26, 438/27, 438/29
• US Class Current: 257/98
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: H01L 2223/54426 for alignment
• CPC Class Codes: H01L 2223/54473 for use after dicing
• CPC Class Codes: H01L 2223/54486 Located on package parts, e.g. encapsulation, leads, package substrate
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/16 with a particular crystal structure or orientation, e.g. polycrystalline, amorphous or porous
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/483 Containers

Abstract

A polarized light emitting diode (LED) includes a marker indicating a polarization direction. A package for the LED also includes a marker indicating the polarization direction. The markers on the LED and package are used for mutual alignment, wherein the LED is attached in a favorable orientation with respect to a package, so that the polarization direction of emitted light from the package is apparent. The marker is placed on the LED before die separation and the marker is placed on the package before alignment. The marker on the LED comprises a photolithographic pattern, an asymmetric die shape, a notch on the die, or a scratch on the die, while the marker on the package comprises an electrode shape or pattern, an asymmetric package shape, a notch on the package, or a scratch on the package. Finally, the LED or package may be installed in an external circuit or system that also indicates the polarization direction.

Claims

1. A polarized light emitting diode (LED) apparatus, comprising:

at least one LED, for emitting polarized light, including at least one first marker indicating a light polarization direction of the LED; and

a package, for containing the LED, including at least one second marker indicating a light polarization direction of the package;

wherein the LED is positioned within the package by aligning the first marker with the second marker.

2. The polarized LED apparatus of claim 1, wherein the LED is attached in a favorable orientation with respect to the package, so that the light polarization direction of emitted light from the LED is apparent.

3. The polarized LED apparatus of claim 1, wherein the first marker on the LED and the second marker on the package are used for mutual alignment.

4. The polarized LED apparatus of claim 1, wherein the first marker is placed or defined on the LED before die separation and the second marker is placed or defined on the package before alignment.

5. The polarized LED apparatus of claim 1, wherein the first marker on the LED comprises a photolithographic pattern, an electrode shape or pattern, an asymmetric die shape, a notch on the die, ot a scratch on the die.

6. The polarized LED apparatus of claim 1, wherein the second marker on the package comprises an electrode shape or pattern, an asymmetric package shape, a notch on the package, or a scratch on the package.

8. The polarized LED apparatus of claim 1, wherein the package contains an array of the polarized LEDs.

7. The polarized LED apparatus of claim l, wherein the LED is installed in an external circuit or system that utilizes the light polarization, and the external circuit or system includes at least one third marker indicating a light polarization direction of the external circuit or system, wherein the package is positioned within the external circuit aligning the second marker with the third marker.

9. A method of fabricating a polarized light emitting diode (LED) apparatus, comprising:

obtaining at least one LED, for emitting polarized light, including at least one first marker indicating a light polarization direction of the LED;

obtaining a package, for containing the LED, including at least one second marker indicating a light polarization direction of the package; and

positioning the LED within the package by aligning the first marker with the second marker.

10. The method of claim 9, wherein the light polarization direction is determined from the LED'"'"'s crystallographic orientation.

11. The method of claim 9, wherein the LED is attached in a favorable orientation with respect to the package, so that the polarization direction of emitted light from the LED is apparent.

12. The method of claim 9, wherein the first marker on the LED and the second marker on the package are used for mutual alignment.

13. The method of claim 12, wherein the first marker is placed or defined on the LED before die separation and the second marker is placed or defined on each package before alignment.

14. The method of claim 12, wherein the first marker on the LED comprises a photolithographic pattern, an electrode shape or pattern, an asymmetric die shape, a notch on the die, or a scratch on the die.

15. The method of claim 12, wherein the second marker on the package comprises an electrode shape or pattern, an asymmetric package shape, a notch on the package, or a scratch on the package.

16. The method of claim 9, wherein the LED is installed in an external circuit or system that utilizes the light polarization, and the external circuit or system includes at least one third marker indicating a light polarization direction of the external circuit or system, wherein the package is positioned within the external circuit by aligning the second marker with the third marker.

17. The method of claim 9, wherein the package contains an array of the polarized LEDs.

18. A light emitting diode (LED) apparatus, comprising:

at least one LED, having at least one orientation dependent emission characteristic, including at least one first marker indicating an orientation of the LED for which the orientation dependent emission characitinsoc is a maximum; and

a package, for containing the LED, including at least one second marker indicating an orientation of the package for which the orientation dependent emission characteristic is a maximum;

wherein the LED is positioned within the package by aligning the first marker with the second marker.

19. A method of fabricating at least one light emitting diode (LED) apparatus, comprising:

obtaining at least one LED, having an orientation dependent emission characteristic, including at least one first marker indicating an orientation of the LED for which the orientation dependent characteristic is a maximum; and

obtaining a package, for containing the LED, including at least one second marker indicating an orientation of the package for which the orientation dependent emission characteristic is a maximum;

wherein the LED is positioned within the package by aligning the first marker with the second marker.