HIGH PERFORMANCE LIGHT EMITTING DIODE WITH VIAS
High performance light emitting diode with vias. In accordance with a first embodiment of the present invention, an article of manufacture includes a light emitting diode. The light emitting diode includes a plurality of filled vias configured to connect a doped region on one side of the light emitting diode to a plurality of contacts on the other side of the light emitting diode. The filled vias may comprise less that 10% of a surface area of the light emitting diode.
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This application claims the benefit of priority of U.S. patent application Ser. No. 13/543,697 filed Jul. 6, 2012 and U.S. patent application Ser. No. 14/466,993 filed Aug. 23, 2014.
FIELD OF INVENTIONEmbodiments of the present invention relate to the field of integrated circuit design and manufacture. More specifically, embodiments of the present invention relate to systems and methods for high performance light emitting diodes with vias.
BACKGROUNDLight emitting diodes (LEDs) are gaining wide acceptance in a variety of area-illumination applications, for example, architectural lighting, residential illumination, industrial lighting, outdoor lighting, theatrical lighting and the like.
Conventional light emitting diodes typically have electrical contacts facing in the same direction, e.g., away from a substrate. Some types of LEDs may have electrical contacts at two different levels, e.g., in a “stair step” arrangement. However, the electrical contacts are still typically facing in the same direction.
Unfortunately, such contacts and associated structures tend to block some light output from an LED. In addition, such contact structures present a rather poor path for conducting thermal heat away from an LED. Further, convention contact structures generally result in an uneven electrical field distribution within the LED, leading to a further decrease in power efficiency and light output.
SUMMARY OF THE INVENTIONTherefore, what is needed are systems and methods for high performance light emitting diodes with vias. What is additionally needed are systems and methods for high performance light emitting diodes with vias that enable wafer level packaging, improved thermal conduction and electrical field distribution, and further enable electrical contacts on opposite sides. A further need exists for systems and methods for high performance light emitting diodes with vias that are compatible and complementary with existing systems and methods of integrated circuit design, manufacturing and test. Embodiments of the present invention provide these advantages.
In accordance with a first embodiment of the present invention, an article of manufacture includes a light emitting diode. The light emitting diode includes a plurality of filled vias configured to connect a doped region on one side of the light emitting diode to a plurality of contacts on the other side of the light emitting diode. The filled vias may comprise less that 10% of a surface area of the light emitting diode.
In accordance with another embodiment of the present invention, a light emitting diode apparatus includes an n-doped semiconductor region, a multiple quantum well (MQW) region disposed on said n-doped semiconductor region and a p-doped semiconductor region disposed on said MQW region. The apparatus also includes a plurality of filled vias through said p-doped semiconductor region and through said MQW region, contacting said n-doped semiconductor region. Both terminals of said light emitting diode apparatus are on the same side of said light emitting diode apparatus as said p-doped semiconductor region.
In accordance with yet another embodiment of the present invention, an apparatus includes a light emitting diode. The light emitting diode includes an n-doped semiconductor region, a multiple quantum well (MQW) region disposed on said n-doped semiconductor region and a p-doped semiconductor region disposed on said MQW region. In addition, the apparatus includes a plurality of filled vias through said p-doped semiconductor region and through said MQW region, contacting said n-doped semiconductor region and a carrier substrate. The apparatus further includes a conductive pattern supported by said carrier substrate and metal for electrically coupling said plurality of filled vias to said conductive pattern. The carrier substrate may be configured to couple thermal energy away from said light emitting diode.
The detailed description is described with reference to accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
Reference will now be made in detail to various embodiments of the invention, High Performance Light Emitting Diode with Vias, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with these embodiments, it is understood that they are not intended to limit the invention to these embodiments. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims. Furthermore, in the following detailed description of the invention, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be recognized by one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the invention.
Notation and NomenclatureSome portions of the detailed descriptions which follow (e.g., process 200, 300, 330, 340, 350, 400) are presented in terms of procedures, steps, logic blocks, processing, and other symbolic representations of operations on data bits that may be performed on computer memory. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. A procedure, computer executed step, logic block, process, etc., is here, and generally, conceived to be a self-consistent sequence of steps or instructions leading to a desired result. The steps are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in a computer system. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.
It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the present invention, discussions utilizing terms such as “depositing” or “processing” or “sputtering” or “coating” or “placing” or “slicing” or “forming” or “mounting” or “applying” or “roughening” or “filling” or “accessing” or “performing” or “generating” or “adjusting” or “creating” or “executing” or “continuing” or “indexing” or “computing” or “translating” or “calculating” or “determining” or “measuring” or “gathering” or “running” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
As used herein, and by those of ordinary skill in the art, the term “via” may be used to describe or refer to a hole or a filled hole, generally used to electrically couple circuit elements at different levels of a multi-level structure. In accordance with embodiments of the present invention, vias may also have a “trench” structure, e.g., a hole or filled hole in which the length is much greater than the width. In general, herein, vias may be illustrated as generally circular in vertical cross section. However, it is to be understood that vias and/or filled vias may have any suitable shape.
High Performance Light Emitting Diode with ViasDisposed on top of the substrate 110 are two layers of insulation 112 and 116. Insulation 112 and 116 may comprise, for example, silicon dioxide (Si02), silicon nitride (Si3N4), benzo-cyclo-butene (BCB), spin-on glass, and the like. In between layers 112 and 116 is a layer of patterned metal 115. Patterned metal 115 routes electrical signals for the LED, as will be described further below. Patterned metal 115 may comprise, for example, aluminum (Al), copper (Cu), nickel (Ni), gold (Au) and the like.
Light emitting diode 100 additionally comprises lower metal 120. Lower metal 120 contacts conductive portions of paternal metal 115. Lower metal 120 may comprise copper (Cu), nickel (Ni), gold (Au), tin (Sn) and the like. The material chosen should be selected to effective bonding to upper metal 130. Upper metal 130 is bonded to lower metal 120. Upper metal 130 may comprise copper (Cu), nickel (Ni), gold (Au), tin (Sn) and the like. The material chosen should be selected to effective bonding to lower metal 120. Upper metal 130 is in electrical contact with contact 155 and or via 140.
Filled vias 140 provides an electrical path from patterned metal 115, through some instances of lower metal 120 and upper metal 130, to the n-type semiconducting material, e.g., n-gallium nitride (n-GaN), of the light emitting diode proper. Filled vias 140 may form an array of separated pillars, in some embodiments. Filled vias 140 may from long trenches (in a direction parallel to the MQW plan), in some embodiments. Filled vias 140 may from an enclosed loop of thin side walls wrapping around the device, in some embodiments. In addition, filled vias 140 may directly contact optional layer 170 of a transparent conductive material, further described below. Filled vias 140 may comprise, for example, chrome/gold (Cr/Au), titanium/gold, titanium/aluminum/nickel/gold (Ti/Al/Ni/Au) stacks, and the like.
In accordance with embodiments of the present invention, vias 140 may also be described as a “trench” structure, e.g., a filled hole in which the length, e.g., perpendicular to the plane of
Contact 155 provides electrical contact from some instances of upper metal 130 to the p-type semiconducting material, e.g., p-gallium nitride (p-GaN), of the light emitting diode proper. Contact 155 may comprise, for example, chrome/gold (Cr/Au), nickel/gold (Ni/Au), nickel palladium/gold (Ni/Pd/Au) stacks, and the like.
Light emitting diode 100 further comprises insulating structures 150. Insulating structure 150 insulate the p-type semiconducting material from filled vias 140 and from some upper metal 130.
Light emitting diode 100 comprises a stack of active materials 190 that emits light. For example, stack 190 may comprise a p-type semiconducting material, e.g., p-gallium nitride (p-GaN), multiple quantum wells (MQW) and n-type semiconducting material, e.g., n-gallium nitride (n-GaN). The top surface 160, e.g., n-GaN, of the active stack 190 may be roughened in order to improve light extraction, in accordance with embodiments of the present invention.
Light emitting diode 100 comprise an optional layer 170 of a transparent conductive material, e.g., indium tin oxide (ITO), supported by a metal grid 145 (
As illustrated in
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As illustrated in
In
In accordance with embodiments of the present invention, the substrate wafer 310 can also be etched deeply, leaving a thin layer of substrate material remaining, and this thin layer can be finally polished off after other process operations are complete, e.g., after seed layer removal.
As illustrated in
It is appreciated that the processes described above may take place at a wafer level. For example, substrate 292 (
In addition, in accordance with embodiments of the present invention, the wafer may be singulated, e.g., cut between vias and contact structures, into smaller-area light emitting diodes.
In accordance with embodiments of the present invention, the high efficiency light emitting diode with vias may be coupled to a heat sink, e.g., on the bottom of substrate 310.
With reference to the top view in
With reference to the bottom view in
Light appliance 600 additionally comprises a body portion 620 that houses power conditioning electronics (not shown) that convert 110 V AC input electrical power (or 220 V AC, or other selected input electrical power) to electrical power suitable for driving a plurality of light emitting diode devices 640. Body portion 620 may also comprise, or couple to, optional heat sink features (not shown).
Light appliance 600 may additionally comprise optional optics 630. Optics 630 comprise diffusers and/or lenses for focusing and/or diffusing light from the plurality of light emitting diode devices 640 into a desired pattern.
Light appliance 600 comprises a plurality of high efficiency light emitting diode with vias devices. Individual instances of plurality of high efficiency light emitting diode with vias devices may correspond to assemblies previously described herein. For example light appliance 600 may include one or more instances of a high efficiency light emitting diode with vias 100. Each instance of a high efficiency light emitting diode with vias 100 may comprise one or more light emitting diodes. It is appreciated that not all high efficiency light emitting diode with vias 100 need be identical, and that not all light emitting diodes in a single instance of high efficiency light emitting diode with vias 100 need be identical.
It is to be further appreciated that appliance 600 may comprise a plurality of individual, different, LED devices. For example, one instance of an electronic device may be a blue light emitting diode comprising a sapphire substrate. Another instance of an electronic device may be a green light emitting diode comprising a gallium phosphide (GaP) substrate. Another instance of an electronic device may be a red light emitting diode comprising a gallium arsenide (GaAs) substrate. The three instances of electronic devices may be arranged such that the light from such three colors may be combined to produce a variety of spectral colors. For example, a plurality of light emitting diode devices may operate in combination to produce a “white” light output.
In accordance with embodiments of the present invention, device 600 may include additional electronics associated with the LED devices. In one exemplary embodiment, such additional electronics may comprise circuits to implement a white balance among tri-color LEDs.
Embodiments in accordance with the present invention provide systems and methods for high performance light emitting diodes with vias. In addition, embodiments in accordance with the present invention provide systems and methods for high performance light emitting diodes with vias that enable wafer level packaging, improved thermal conduction and electrical field distribution, and further enable electrical contacts on opposite sides. Further, embodiments in accordance with the present invention provide systems and methods for high performance light emitting diodes with vias that are compatible and complementary with existing systems and methods of integrated circuit design, manufacturing and test.
Various embodiments of the invention are thus described. While the present invention has been described in particular embodiments, it should be appreciated that the invention should not be construed as limited by such embodiments, but rather construed according to the below claims.
Claims
1. A method comprising:
- filling a plurality of vias of a light emitting diode; and
- connecting the plurality of vias to a doped region on one side of the light emitting diode and to a plurality of contacts on the other side of the light emitting diode.
2. The method of claim 1 wherein the vias comprise less than 10% of a surface area of the light emitting diode.
3. The method of claim 1 wherein a distance between any two vias in less than 200 um.
4. The method of claim 1 further comprising adding a transparent conductor on the one side of the light emitting diode, and wherein the plurality of filled vias are electrically coupled to the transparent conductor.
5. The method of claim 1 further comprising adding a plurality of conductive traces on the one side of the light emitting diode, and wherein the plurality of filled vias are electrically coupled to the conductive traces.
6. The method of claim 1 further comprising:
- adding a phosphor layer and an optical element bonded to the one side of the light emitting diode.
7. The method of claim 1 further comprising: adding a carrier wafer bonded to the plurality of filled vias.
8. The method of claim 7 wherein the carrier wafer comprises at least one material of the set of silicon, ceramic, glass, tungsten, molybdenum, invar, aluminum, nickel, steel, brass and copper.
9. The method of claim 7 wherein the carrier wafer comprises a printed circuit board laminate.
10. The method of claim 7 wherein the carrier wafer is characterized as having a thermal conductivity greater than 10 W/mK.
11. The method of claim 7 wherein the carrier wafer is further coupled to a heat sink device.
12. The method of claim 5 wherein the conductive traces are placed laterally on top of the surface of the carrier wafer and are configured to make electrical contact with external circuitry.
13. The method of claim 5 wherein the conductive traces are placed laterally on top of the surface of the carrier wafer and are configured to make electrical contact with external circuitry, while a second electrode is configured to make electrical contact with external circuitry through the thickness of the carrier wafer.
14. The method of claim 7 wherein both electrodes or the light emitting diode connect to external circuitry through the thickness of the carrier wafer.
15. The method of claim 1 wherein a substrate utilized for growing the light emitting diode is absent.
16. The method of claim 1 further comprising connecting to electronics to convert a source of alternating current to direct current for use by the light emitting diode; and a base to couple the electronics to the source of alternating current.
Type: Application
Filed: Feb 10, 2017
Publication Date: Jan 30, 2020
Applicant: Invensas Corporation (San Jose, CA)
Inventors: Ilyas Mohammed (Santa Clara, CA), Liang Wang (Milpitas, CA)
Application Number: 15/430,428