Light emitting devices and components having improved chemical resistance and related methods

Light emitting devices and components having excellent chemical resistance and related methods are disclosed. In one embodiment, a component of a light emitting device can include a silver (Ag) portion, which can be silver on a substrate, and a protective layer disposed over the Ag portion. The protective layer can at least partially include an inorganic material for increasing the chemical resistance of the Ag portion.

CROSS REFERENCE TO RELATED APPLICATION

This application relates and claims priority to U.S. Provisional Patent Application Ser. No. 61/510,310, filed Jul. 21, 2011, the disclosure of which is hereby incorporated by reference its entirety.

TECHNICAL FIELD

The subject matter herein relates generally to light emitting devices, components and methods. More particularly, the subject matter herein relates to light emitting devices, components and methods with improved resistance to chemicals and/or chemical vapors or gases that can adversely affect the brightness and reliability of such devices.

BACKGROUND

Light emitting diodes (LEDs), can be utilized in light emitting devices or packages for providing white light (e.g., perceived as being white or near-white), and are developing as replacements for incandescent, fluorescent, and metal halide high-intensity discharge (HID) light products. Conventional LED devices or packages can incorporate components such as metallic traces or mounting surfaces which can become tarnished, corroded, or otherwise degraded when exposed to various undesirable chemicals and/or chemical vapors. Such chemicals and/or chemical vapors can enter conventional LED devices, for example, by permeating an encapsulant filling material disposed over such components. In one aspect, undesirable chemicals and/or chemical vapors can contain sulfur, sulfur-containing compounds (e.g., sulfides, sulfites, sulfates, SOx), chlorine and bromine containing complexes, nitric oxide or nitrogen dioxides (e.g., NOx), and oxidizing organic vapor compounds which can permeate the encapsulant and physically degrade various components within the LED device via corroding, oxidizing, darkening, and/or tarnishing such components. Such degradation can adversely affect brightness, reliability, and/or thermal properties of conventional LED devices over time, and can further adversely affect the performance of the devices during operation.

Despite the availability of various light emitting devices in the marketplace, a need remains for devices and components having improved chemical resistance and related methods for preventing undesirable chemicals and/or chemical vapors from reaching and subsequently degrading components within the devices. Devices, components, and methods described herein can advantageously improve chemical resistance to undesirable chemicals and/or chemical vapors within encapsulated LED devices, while promoting ease of manufacture and increasing device reliability and performance in high power and/or high brightness applications. Described methods can be used and applied to create chemically resistant surface mount device (SMD) type of LED devices of any size, thickness, and/or dimension. Devices, components, and methods described herein can advantageously be used and adapted within any style of LED device, for example, devices including a single LED chip, multiple chips, and/or multi-arrays of LEDs and/or devices incorporating different materials for the body or submount such as plastic, ceramic, glass, aluminum nitride (AlN), aluminum oxide (Al2O3), printed circuit board (PCB), metal core printed circuit board (MCPCB), and aluminum panel based devices. Notably, devices, components, and methods herein can prevent degradation of optical and/or thermal properties of devices or packages incorporating silver (Ag) or Ag plated components by preventing tarnishing of the Ag or Ag-plated components.

DETAILED DESCRIPTION

Reference will now be made in detail to possible aspects or embodiments of the subject matter herein, one or more examples of which are shown in the figures. Each example is provided to explain the subject matter and not as a limitation. In fact, features illustrated or described as part of one embodiment can be used in another embodiment to yield still a further embodiment. It is intended that the subject matter disclosed and envisioned herein covers such modifications and variations.

As illustrated in the various figures, some sizes of structures or portions are exaggerated relative to other structures or portions for illustrative purposes and, thus, are provided to illustrate the general structures of the present subject matter. Furthermore, various aspects of the present subject matter are described with reference to a structure or a portion being formed on other structures, portions, or both. As will be appreciated by those of skill in the art, references to a structure being formed “on” or “above” another structure or portion contemplates that additional structure, portion, or both may intervene. References to a structure or a portion being formed “on” another structure or portion without an intervening structure or portion are described herein as being formed “directly on” the structure or portion. Similarly, it will be understood that when an element is referred to as being “connected”, “attached”, or “coupled” to another element, it can be directly connected, attached, or coupled to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected”, “directly attached”, or “directly coupled” to another element, no intervening elements are present.

Furthermore, relative terms such as “on”, “above”, “upper”, “top”, “lower”, or “bottom” are used herein to describe one structure's or portion's relationship to another structure or portion as illustrated in the figures. It will be understood that relative terms such as “on”, “above”, “upper”, “top”, “lower” or “bottom” are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, structure or portion described as “above” other structures or portions would now be oriented “below” the other structures or portions. Likewise, if devices in the figures are rotated along an axis, structure or portion described as “above”, other structures or portions would now be oriented “next to” or “left of” the other structures or portions. Like numbers refer to like elements throughout.

Unless the absence of one or more elements is specifically recited, the terms “comprising,” including,” and “having” as used herein should be interpreted as open-ended terms that do not preclude the presence of one or more elements.

Light emitting devices according to embodiments described herein can comprise group III-V nitride (e.g., gallium nitride (GaN)) based light emitting diodes (LEDs) or lasers that can be fabricated on a growth substrate, for example, a silicon carbide (SiC) substrate, such as those devices manufactured and sold by Cree, Inc. of Durham, N.C. Other growth substrates are also contemplated herein, for example and not limited to sapphire, silicon (Si) and GaN. In one aspect, SiC substrates/layers can be 4H polytype silicon carbide substrates/layers. Other Sic candidate polytypes, such as 3C, 6H, and15R polytypes, however, can be used. Appropriate SiC substrates are available from Cree, Inc., of Durham, N.C., the assignee of the present subject matter, and the methods for producing such substrates are set forth in the scientific literature as well as in a number of commonly assigned U.S. patents, including but not limited to U.S. Pat. No. Re. 34,861; U.S. Pat. No. 4,946,547; and U.S. Pat. No. 5,200,022, the disclosures of which are incorporated by reference herein in their entireties. Any other suitable growth substrates are contemplated herein.

As used herein, the term “Group III nitride” refers to those semiconducting compounds formed between nitrogen and one or more elements in Group III of the periodic table, usually aluminum (Al), gallium (Ga), and indium (In). The term also refers to binary, ternary, and quaternary compounds such as GaN, AlGaN and AlInGaN. The Group III elements can combine with nitrogen to form binary (e.g., GaN), ternary (e.g., AlGaN), and quaternary (e.g., AlInGaN) compounds. These compounds may have empirical formulas in which one mole of nitrogen is combined with a total of one mole of the Group III elements. Accordingly, formulas such as AlxGa1-xN where 1>x>0 are often used to describe these compounds. Techniques for epitaxial growth of Group III nitrides have become reasonably well developed and reported in the appropriate scientific literature.

Although various embodiments of LEDs disclosed herein comprise a growth substrate, it will be understood by those skilled in the art that the crystalline epitaxial growth substrate on which the epitaxial layers comprising an LED are grown can be removed, and the freestanding epitaxial layers can be mounted on a substitute carrier substrate or substrate which can have different thermal, electrical, structural and/or optical characteristics than the original substrate. The subject matter described herein is not limited to structures having crystalline epitaxial growth substrates and can be used in connection with structures in which the epitaxial layers have been removed from their original growth substrates and bonded to substitute carrier substrates.

Group III nitride based LEDs according to some embodiments of the present subject matter, for example, can be fabricated on growth substrates (e.g., Si, SiC, or sapphire substrates) to provide horizontal devices (with at least two electrical contacts on a same side of the LED) or vertical devices (with electrical contacts on opposing sides of the LED). Moreover, the growth substrate can be maintained on the LED after fabrication or removed (e.g., by etching, grinding, polishing, etc.). The growth substrate can be removed, for example, to reduce a thickness of the resulting LED and/or to reduce a forward voltage through a vertical LED. A horizontal device (with or without the growth substrate), for example, can be flip chip bonded (e.g., using solder) to a carrier substrate or printed circuit board (PCB), or wire bonded. A vertical device (with or without the growth substrate) can have a first terminal solder bonded to a carrier substrate, mounting pad, or PCB and a second terminal wire bonded to the carrier substrate, electrical element, or PCB. Examples of vertical and horizontal LED chip structures are discussed by way of example in U.S. Publication No. 2008/0258130 to Bergmann et al. and in U.S. Publication No. 2006/0186418 to Edmond et al., the disclosures of which are hereby incorporated by reference herein in their entireties.

As described further, one or more LEDS can be at least partially coated with one or more phosphors. The phosphors can absorb a portion of the LED light and emit a different wavelength of light such that the LED device or package emits a combination of light from each of the LED and the phosphor. In one embodiment, the LED device or package emits what is perceived as white light resulting from a combination of light emission from the LED chip and the phosphor. One or more LEDs can be coated and fabricated using many different methods, with one suitable method being described in U.S. patent application Ser. Nos. 11/656,759 and 11/899,790, both entitled “Wafer Level Phosphor Coating Method and Devices Fabricated Utilizing Method”, and both of which are incorporated herein by reference in their entireties. Other suitable methods for coating one or more LEDs are described in U.S. patent application Ser. No. 12/014,404 entitled “Phosphor Coating Systems and Methods for Light Emitting Structures and Packaged Light Emitting Diodes Including Phosphor Coating” and the continuation-in-part application U.S. patent application Ser. No. 12/717,048 entitled “Systems and Methods for Application of Optical Materials to Optical Elements”, the disclosures of which are hereby incorporated by reference herein in their entireties. LEDs can also be coated using other methods such electrophoretic deposition (EPD), with a suitable EPD method described in U.S. patent application Ser. No. 11/473,089 entitled “Close Loop Electrophoretic Deposition of Semiconductor Devices”, which is also incorporated herein by reference in its entirety. It is understood that LED devices, systems, and methods according to the present subject matter can also have multiple LEDs of different colors, one or more of which can be white emitting.

Referring now toFIGS. 1 to 13,FIGS. 1 and 2illustrate top and cross-sectional views of one example of a light emitting diode (LED) package or device, generally designated10. In one aspect, LED device10can comprise a surface mount device (SMD) comprising a body12which can be molded or otherwise formed about a leadframe. SMD types of LED devices can be suitable for general LED illumination applications, such as indoor and outdoor lighting, automotive lighting, and preferably suitable for high power and/or high brightness lighting applications. The subject matter disclosed herein can be suitably adapted for application within a wide range of SMD type LED device designs, not limited to dimensional and/or material variations. Notably, devices, components, and methods disclosed herein can maintain the brightness of device10even in the presence of harmful chemicals, chemical vapors, or complexes by provision of a protective barrier or protective layer P (FIG. 2) adapted to prevent harmful chemicals or complexes from tarnishing and/or otherwise degrading components within device10. In one aspect, body12can be disposed about a leadframe comprising a thermal element14and one or more electrical elements, for example, first and second electrical elements16and18, respectively. That is, thermal element14and electrical elements16and18can be collectively referred to as a “leadframe” and can be singulated from a sheet of leadframe components (not shown). A corner notch, generally designated N can be used for indicating electrical polarity of first and second electrical elements16and18. Thermal element14and first and second electrical elements16and18can comprise a material that is electrically and/or thermally conductive such as a metal or metal alloy. In one aspect, thermal element14can be electrically and/or thermally isolated one and/or both of first and second electrical elements16and18by one or more isolating portions20of the body. One or more LED chips or LEDs22can be mounted over thermal element14using any suitable die attach technique(s) and/or material(s), for example only and not limited to die attach adhesive (e.g., silicone, epoxy, or conductive silver (Ag) epoxy) or a metal-to-metal die attach technique such as flux or no-flux eutectic, non-eutectic, or thermal compression die attach.

LEDs22can electrically communicate with one and/or both first and second electrical elements16and18via one or more electrical connectors such as electrically conductive wire bonds24. For illustration purposes, LEDs22with two electrical contacts on the same side (e.g., upper surface) are shown as electrically connected to two electrical elements (e.g.,16and18) via wire bonds24. However, LEDs22having one electrical contact on the upper surface that is electrically connected with a single electrical element is also contemplated. Any type or style of LED22can be used in device10, for example, LED22can comprise a horizontally structured chip (e.g., having at least two electrical contacts on a same side of the LED) or a vertically structured chip (e.g., with electrical contacts on opposing sides of the LED) with or without a growth substrate. LED22can comprise one or more substantially straight cut and/or beveled (i.e., angled) cut sides or surfaces. LED22can comprise a direct attach build (e.g., bonded to a carrier substrate) or a build incorporating a grown substrate such as sapphire, SiC, or GaN. LEDs22having any build, structure, type, style, shape, and/or dimension are contemplated herein. Wire bonds24or other electrical attachment connectors and related methods can be adapted to communicate, transmit, or convey an electrical current or signal from electrical elements16and18to one or more LEDs22thereby causing illumination of the one or more LEDs22. Thermal element14and/or first and second electrical elements16and18, respectively, can be coated, plated, deposited, or otherwise layered with a reflective material (FIG. 2), such as, for example and without limitation, Ag or a Ag-containing alloy for reflecting light from the one or more LEDs22.

Body12can comprise any suitable material molded or otherwise disposed about thermal element14and/or first and second elements16and18, respectively. In one aspect, body12can comprise a ceramic material such as a low temperature co-fired ceramic (LTCC) material, a high temperature co-fired ceramic (HTCC) material, alumina, aluminum nitride (AlN), aluminum oxide (Al2O3), glass, and/or an Al panel material. In other aspects, body12can comprise a molded plastic material such as polyamide (PA), polyphthalamide (PPA), liquid crystal polymer (LCP) or silicone. At least one electrostatic discharge (ESD) protection device25can be disposed within device10and can be electrically connected to electrical elements16and18reverse biased with respect to LEDs22. ESD device25can protect against damage from ESD within device10. In one aspect, different elements can be used as ESD protection devices25such as various vertical silicon (Si) Zener diodes, different LEDs arranged reverse biased to LEDs22, surface mount varistors and lateral Si diodes. As illustrated, ESD device25can comprise a vertically structured device having one electrical contact on the bottom and another electrical contact on the top; however, horizontally structured devices are also contemplated.

Still referring toFIGS. 1 and 2, body12of device10can comprise a cavity, generally designated26, for example, a reflector cavity optionally coated with a reflective material for reflecting light from the one or more LEDs22. AsFIG. 2illustrates, cavity26can be filled at least partially or completely with a filling material, such as an encapsulant28. Encapsulant can optionally comprise one or more phosphor materials adapted to emit light of a desired wavelength when activated by light emitted from the one or more LEDs22. Thus, in one aspect, device10can emit light having a desired wavelength or color point that can be a combination of light emitted from phosphors disposed in encapsulant28and from the light emitted from one or more LEDs22. In one aspect, thermal element14and first and second electrical elements16and18can comprise an inner portion30and an outer portion32. In one aspect, inner portion30and outer portion32can comprise electrically and/or thermally conductive materials. Outer portion32may be applied such that it entirely surrounds inner portion30as shown, or in other aspects outer portion32can optionally plate, coat, or comprise a layer over a single surface or two or more surfaces of portion30.

In one aspect, outer portion32can comprise a highly reflective Ag substrate, substrate containing Ag, or layer of material such as Ag for maximizing light output from device10and for assisting in heat dissipation by conducting heat away from the one or more LEDs22. Outer portion32can also comprise a substrate of Ag-containing alloy instead of pure Ag, and such alloy can contain other metals such as titanium (Ti) or nickel (Ni). Inner portion30can comprise a metal or metal alloy such as copper (Cu) substrate or Cu-alloy substrate. In one aspect, an optional layer of material (not shown) can be disposed between inner portion30and outer portion32, such as a layer of Ni for providing a barrier between the Ag and Cu, thereby preventing defects caused by migratory Cu atoms, such as a defect commonly known as “red plague”. In other aspects, outer portion32can be directly attached to and/or directly coat inner portion30. Outer portion32can advantageously reflect light emitted from the one or more LEDs22thereby improving optical performance of device10. Upper surfaces of thermal element14and electrical elements16and18can be disposed along a floor34of cavity26such that respective upper surfaces of thermal and electrical elements are disposed along the same plane and/or different planes. First and second electrical elements16and18can extend from one or more lateral sides of body12and form one or more external tab portions, generally designated36and38. Tab portions36and38can bend to form one or more lower mounting surfaces such that device10can be mounted to an underlying substrate. Tab portions36and38can outwardly bend away from each other or inwardly bend towards each other thereby adapting either a J-bend or gull-wing orientation as known in the art. However, any configuration of external tabs36and38is contemplated.

Referring toFIG. 2, a filling material can be disposed and filled to any level within cavity26and may be partially disposed below and/or above a top surface40of device10. In one aspect, filling material can comprise an encapsulant28that it is filled to a level flush with top surface40of device as shown. In other aspects, encapsulant28can be filled such that it forms a concave or convex surface with respect to top surface40of device10as indicated by the dotted lines. In one aspect, encapsulant28can be adapted for dispensing within cavity26. Encapsulant28can comprise a selective amount of one or more phosphors adapted to emit light or combinations of light providing device10having a desired color point or color temperature. In one aspect, encapsulant28can comprise a silicone material, such as a methyl or phenyl silicone encapsulant.

Typically, SMD type devices, such as device10, do not have secondary optics (e.g., a secondary lens) for preventing harmful chemicals or complexes from permeating the device and thereby degrading Ag or Ag-alloyed outer portions32of thermal and/or electrical elements. In some aspects, encapsulant28can provide physical protection against foreign solids and liquids, but may not provide adequate protection against gaseous chemicals or airborne elements such as sulfur, oxygen, or moisture which can tarnish or otherwise degrade outer portion32where outer portion comprises Ag (e.g., pure Ag, Ag-alloys or Ag plating). In some aspects, Ag-containing components such as outer portion32of thermal and electrical elements14,16, and18can over time become tarnished, corroded, or otherwise degraded where the device10has poor chemical resistance. This can decrease the brightness of device10. In one aspect, undesirable chemicals, vapors, or complexes C can permeate encapsulant28and potentially interact with outer portion32of elements, for example, by tarnishing such elements thereby resulting in degradation to optical, physical, electrical, and/or thermal properties such as a loss in brightness output and the noticeable darkening of surfaces along cavity floor34. In this embodiment, undesirable chemical vapors or complexes C can permeate the encapsulant28as indicated by the dotted trajectory lines shown inFIG. 2and could potentially adversely affect outer portion32if not deflected from surfaces within the device as shown. Notably, the current subject matter optimizes the chemical resistance of device10by incorporating a protective layer P serving as a protective barrier or barrier layer disposed over one or more surfaces of device10, within device10, and/or over components of device10to prevent complexes C from reaching, interacting with, and/or adversely affecting components such as Ag-containing outer portion32of thermal and electrical elements14,16, and18.

AsFIG. 2illustrates, and in one aspect, protective layer P can be directly disposed over outer portion32of elements as shown along cavity floor34. Protective layer P can be applied before attaching the one or more LEDs22to thermal element14such that protective layer P can be disposed between LED22and outer portion32of thermal/electrical components or elements. Protective layer P can be used either alone or in combination with a phenyl silicone encapsulant for improving the chemical resistance of LED devices as described herein.FIGS. 4 to 13illustrate various other alternative locations of protective layer P for providing protection against chemical complexes C within LED devices or packages. In one aspect, undesired chemicals, vapors, or complexes C can comprise chemical vapors containing sulfur, sulfur containing compounds (sulfides, sulfites, sulfates, SOx), chlorine or bromine containing complexes, nitric oxide or nitrogen dioxide (NOx), and/or oxidizing organic vapor compounds. Complexes C can degrade the Ag components (e.g., outer portion32of thermal/electrical elements) and result in a loss of brightness output and noticeable darkening of surfaces within the device. The current subject matter can optimize the chemical resistance of device10and components within device10such that harmful vapors, chemicals, or complexes C cannot reach Ag-containing components (e.g., outer portion32) as illustrated by the dotted trajectory of complexes C being repelled from the surface of protective layer P, thereby minimizing the damage to reflective Ag components, and further minimizing and/or totally preventing any loss in brightness from device10and/or darkening of components within device10.

Protective layer P can be directly and/or indirectly disposed over vulnerable components within devices described herein, such as located directly or indirectly over Ag or Ag-alloy containing components. Protective layer P can be adapted for application to a variety of surfaces of components within LED devices which is advantageous. In one aspect, protective layer P can be directly applied to portions of surfaces of Ag or Ag-alloy containing components (e.g., outer portions32of thermal element14and electrical elements16,18) alone and/or layer P can be applied to portions of surfaces of LED chips22including underfills, on or over wires, wire bonds24, wire bond balls (e.g., ball formed where wire24attaches to LED chip22), and on surfaces of the LED housing or body all of which, when comprising a portion or layer of Ag over the surface, can comprise Ag-containing components. Protective layer P can be applied over portions of a ceramic or plastic body of LED device, for example, isolating portions20of body12(FIG. 2). Notably, protective layer P can be selectively applied at or parallel to any number of processing steps within the manufacturing process (e.g., before/after die attachment of LED, before/during/after encapsulation, seeFIGS. 4 to 13) for providing broad protection against chemical vapors, such as but not limited to, nitric oxide or nitrogen dioxide (NOx), oxidizing organic vapor compounds, sulfur, sulfur-containing compounds (e.g., sulfides, sulfates, SOx) and chlorine- or bromine-containing complexes. Notably, when a protective layer P is incorporated, devices described herein can exhibit excellent chemical, including sulfur, resistance and long lasting protection against chemical complexes C as compared to conventional devices. In one aspect, improved devices, such as device10, can retain approximately 95% or more of its initial brightness value (e.g., measured in lumens) when exposed to a sulfur environment as compared to conventional devices which may only retain approximately 60% of its initial brightness value when exposed to the same sulfur environment. Depending on the level of sulfur present and severity of the environment, improved devices such as device10can retain approximately 100% of their initial brightness value.

Various devices, for example, SMD type devices shown and described herein can comprise a protective barrier or protective layer P. Protective layer P is not limited in application or use, and can be used in devices comprising ceramic, plastic, PCB, MCPCB, or laminate substrates or submounts and can advantageously be applied over multiple surfaces, including LEDs22disposed within the SMDs. Protective layer P can at least partially comprise an inorganic material for increasing chemical resistance of the substrate. The inorganic material can comprise an inorganic coating, an inorganic film with an organic or silicone matrix material, and/or an inorganic oxide coating having a thickness ranging from approximately 1 nm to 100 μm. As used herein “inorganic coating(s)”, “inorganic layer(s)”, “inorganic film(s)” and/or “inorganic oxide coating(s)” can include some organic material or component in the mixture in addition to the inorganic material or component. Such coating(s), layer(s), and/or film(s) as used herein can be mostly inorganic, primarily SiOxin nature, however, there may generally be some organic component remaining. Any sub-range of protective layer P thickness between approximately 1 nm and 100 μm is also contemplated herein, for example, thicknesses ranging between approximately 1 and 10 nm; 10 nm and 50 nm; 50 nm and 200 nm; 200 nm and 400 nm; 400 and 600 nm; 600 and 800 nm; 800 nm and 1 μm; 1 μm and 5 μm; 5 μm and 10 μm; 10 μm and 50 μm; and 50 μm and 100 μm are contemplated. Protective layer P can also comprise a thickness ranging from approximately 1 nm to 100 nm, 100 nm to 500 nm, and 0.5 μm to 20 μm are also contemplated herein. In one aspect, a thicker protective layer P can provide superior barrier protection of Ag components against harmful chemical complexes C, thereby improving the brightness retention of LED device10. Protective layer P can be applied via any suitable technique, such as, for example and without limitation, spinning on, dispensing, brushing, painting, dipping, plating, spraying, screen-printing and/or chemical or physical vapor deposition (CVD or PVD) techniques. Of note, however, spinning on, brushing, painting, spraying, etc. may be advantageous, as such techniques can be easier to apply than CVD or PVD processing (e.g., as such techniques do not require a vacuum, require less equipment, and reduce the cost).

In one aspect, protective layer P can comprise a Si-containing inorganic oxide coating. For example, protective layer P can comprise an inorganic oxide coating selected from the group consisting of, but not limited to, organosilicate glass, organosilicate solution, organosilicate dispersion, organosilicate sol-gel, Si-containing spin-on glass (SOG) materials, spin-on polymer materials, and/or spin-on dielectric materials. As noted earlier, and as used herein “inorganic oxide coating(s)” are mostly inorganic, primarily SiOxin nature, however, there may generally be some organic component remaining hence the “organosilicate” terminology. Precursors of inorganic or inorganic oxide in solution, dispersion, sol-gel, or liquid form can be used to form protective layer P. SOG materials can comprise glasses selected from various product or glass families, such as the silicate family, phosphosilicate family, siloxane family, methylsiloxane family, silsesquioxane family, and dopant-containing variations of these families. Spin-on dielectric materials are mostly delivered in solution form known as flowable oxides. Spin-on materials can be supplied, for example, by suppliers such as Filmtronics, Inc., headquartered in Butler, Pa., Desert Silicon, LLC headquartered in Glendale, Ariz., or Honeywell Electronic Materials having sales offices in North America, Asia, and Europe.

Dopant-containing SOG or spin-on dielectric materials in various delivery forms can also be used to form protective layer P. Notably, the application of SOG materials to components within LED devices can be optimized in terms of adopting novel application methods, curing schedules, and/or curing temperatures. In one aspect, SOG materials can be, but are not limited to application via spin-on techniques. For example, novel methods of applying SOG materials can include dispensing, dipping, painting, screen printing, brushing, and spraying such materials such that they achieve the unexpected result of protecting LED components from undesirable chemical components which can permeate LED devices. Notably, protective layer P can, but does not have to have a uniform thickness. Also of note, SOG materials typically need to be cured at temperatures of greater than approximately 300° C. In some aspects, SOG materials require curing at temperatures greater than approximately 425° C. As LED devices can comprise bodies (e.g., body12) that are formed from molded plastic which can melt at approximately 300° C. or less, SOG materials can be cured via novel curing schedules including curing at temperatures that are less than approximately 300° C. such that the plastic body is not susceptible to softening and/or melting. In some aspects, protective layer P can comprise SOG materials cured at temperatures of approximately 300° C. or less such as approximately 250° C. or less, approximately 200° C. or less, approximately 150° C. or less, or approximately 100° C. or less.

Such novel curing schedules and temperatures can unexpectedly produce films which do not crack or shrink and which can be useful for protecting the LED device and/or components within the LED device against undesirable chemical components that can permeate the encapsulant of LED devices. The SOG materials described herein can be chosen for use depending on the type of package body or device used (e.g., ceramic based body, molded plastic body, etc.) and optimized cure schedules/temperatures and/or application method can be considered before adopting a given material for protective layer P. Conventional wisdom regarding the manufacture of LED packages or devices conflicts with using SOG materials within and/or over surfaces of such devices, as SOG materials can be difficult to apply, susceptible to cracking and/or shrinking, and can require high curing temperatures. Notably, devices and components herein can unexpectedly incorporate SOG materials which are optimized with respect to application and/or curing techniques and adapted for use in LED devices described herein to provide excellent chemical resistance against undesired chemicals, chemical vapors, or chemical complexes which can tarnish, corrode, or adversely affect components and brightness of LED devices.

FIGS. 3 and 4illustrate top perspective and cross-sectional views of another embodiment of an LED package or device, generally designated50. LED device50can also be optimized for chemical resistance by incorporating a protective layer P, for example, on an external surface of device50and/or on internal surfaces of device (FIG. 4). LED device50can comprise an SMD type device, similar to device10in that a secondary optics is not used. Thus, the possibility of degradation of device components exists where undesirable chemical vapors or complexes C permeate the filling material of the device (FIG. 4). LED device50can comprise a submount52over which an emission area, generally designated54, can be disposed. Emission area54can comprise one or more LEDs22disposed under a filling material, such as an encapsulant58(seeFIG. 4). In one aspect, emission area54can be substantially centrally disposed with respect to submount52of LED device50. In the alternative, emission area54can be disposed at any location over LED device50, for example, in a corner or adjacent an edge. Any location is contemplated, and more than one emission area54is also contemplated. For illustration purposes, a single, circular emission area54is shown; however, the number, size, shape, and/or location of emission area54can change subject to the discretion of LED device consumers, manufacturers, and/or designers. Emission area54can comprise any suitable shape such as a substantially circular, square, oval, rectangular, diamond, irregular, regular, or asymmetrical shape. LED device50can further comprise a retention material56at least partially disposed about emission area54where retention material56can be referred to as a dam. Retention material56can comprise any material such as a silicone, ceramic, thermoplastic, and/or thermosetting polymer material. In one aspect, retention material56is adapted for dispensing about emission area54, which is advantageous as it is easy to apply and easy to obtain any desired size and/or shape.

Submount52can comprise any suitable mounting substrate, for example, a printed circuit board (PCB), a metal core printed circuit board (MCPCB), an external circuit, a dielectric laminate panel, a ceramic panel, an Al panel, AlN, Al2O3, or any other suitable substrate over which lighting devices such as LEDs may mount and/or attach. LEDs22disposed in emission area54can electrically and/or thermally communicate with electrical elements disposed with submount52, for example, conductive traces (FIG.4). Emission area54can comprise a plurality of LED chips, or LEDs22disposed within and/or below a filling material58such as illustrated inFIG. 4. LEDs22can comprise any suitable size and/or shape of chip and can be vertically structured (e.g., electrical contacts on opposing sides) and/or horizontally structured (e.g., contacts on the same side or surface). LEDs22can comprise any style of chip for example, straight cut and/or bevel cut chips, a sapphire, SiC, or GaN growth substrate or no substrate. One or more LEDs22can form a multi-chip array of LEDs22electrically connected to each other and/or electrically conductive traces in combinations of series and parallel configurations. In one aspect, LEDs22can be arranged in one or more strings of LEDs, where each string can comprise more than one LED electrically connected in series. Strings of LEDs22can be electrically connected in parallel to other strings of LEDs22. Strings of LEDs22can be arranged in one or more pattern (not shown). LEDs22can be electrically connected to other LEDs in series, parallel, and/or combinations of series and parallel arrangements depending upon the application.

Referring toFIG. 3, LED device50can further comprise at least one opening or hole, generally designated60, that can be disposed through or at least partially through submount52for facilitating attachment of LED device50to an external substrate, circuit, or surface. For example, one or more screws can be inserted through the at least one hole60for securing device50to another member, structure, or substrate. LED device50can also comprise one or more electrical attachment surfaces62. In one aspect, attachment surfaces62comprise electrical contacts such as solder contacts or connectors. Attachment surfaces62can be any suitable configuration, size, shape and/or location and can comprise positive and negative electrode terminals, denoted by the “+” and/or “−” signs on respective sides of device50, through which an electrical current or signal can pass when connected to an external power source.

One or more external electrically conductive wires (not shown) can be physically and electrically attached to attachment surfaces62via welding, soldering, clamping, crimpling, inserting, or using any other suitable gas-tight solder free attachment method known in the art. That is, in some aspects, attachment surfaces62can comprise devices configured to clamp, crimp, or otherwise attached to external wires (not shown). Electrical current or signal can pass into LED device50from the external wires electrically connected to device10at the attachment surfaces62. Electrical current can flow into the emission area54to facilitate light output from the LED chips disposed therein. Attachment surfaces62can electrically communicate with LEDs22of emission area54via conductive traces64and66(FIG. 4). That is, in one aspect attachment surfaces62can comprise a same layer of material as first and second conductive traces64and66(FIG. 4) and therefore can electrically communicate to LEDs22attached to traces64and66via electrical connectors such as wire bonds24. Electrical connectors can comprise wire bonds24or other suitable members for electrically connecting LEDs22to first and second conductive traces64and66(FIG. 4).

As shown inFIG. 4, a filling material58can be disposed between inner walls of retention material56. Filling material58can comprise an encapsulant that can include a predetermined, or selective, amount of one or more phosphors and/or lumiphors in an amount suitable for any desired light emission, for example, suitable for white light conversion or any given color temperature or color point. Alternatively, no phosphors may be included in filling material58. Filling material58can comprise a silicon encapsulant material, such as a methyl and/or phenyl silicone material. Filling material58can interact with light emitted from the plurality of LEDs22such that a perceived white light, or any suitable and/or desirable wavelength of light, can be observed. Any suitable combination of encapsulant and/or phosphors can be used, and combinations of differently colored phosphors and/or LEDs22can be used for producing any desired color points(s) of light. Retention material56can be adapted for dispensing, positioning, damming, or placing, about at least a portion of emission area54. After placement of retention material56, filling material58can be selectively filled to any suitable level within the space disposed between one or more inner walls of retention material56. For example, filling material58can be filled to a level equal to the height of retention material56or to any level above or below retention material56, for example, as indicated by the broken lines terminating at retention material56shown inFIG. 4. The level of filling material58can be planar or curved in any suitable manner, such as concave or convex (e.g., see broken lines inFIG. 4).

FIG. 4illustrates retention material56dispensed or otherwise placed over submount52after wire bonding the one or more LEDs22such that retention material56is disposed over and at least partially covers at least a portion of the wire bonds24. For example, wire bonds24of the outermost edge LEDs in a given set or string of LEDs22can be disposed within retention material14. For illustration purposes, only four LEDs22are illustrated and are shown as electrically connected in series via wire bonds24, however, device can contain many strings of LEDs22of any number, for example, less than four or more than four LEDs22can be electrically connected in series, parallel, and/or combinations of series and parallel arrangements. Strings of LEDs22can comprise diodes of the same and/or different colors, or wavelength bins, and different colors of phosphors can be used in the filling material58disposed over LEDS22that are the same or different colors in order to achieve emitted light of a desired color temperature or color point. LEDs22can attach to conductive pad70or intervening layers (e.g., layers68and/or protective layer P, described below) disposed between LED22and conductive pad70using any die attach technique or materials as known in art and mentioned above, for example epoxy or metal-to-metal die attach techniques and materials.

LEDs22can be arranged, disposed, or mounted over an electrically and/or thermally conductive pad70. Conductive pad70can be electrically and/or thermally conductive and can comprise any suitable electrically and/or thermally conducting material. In one aspect, conductive pad70comprises a layer of Cu or a Cu substrate. LEDs22can be electrically connected to first and second conductive traces64and66. One of first and second conductive traces64and66can comprise an anode and the other a cathode. Conductive traces64and66can also comprise a layer of electrically conductive Cu or Cu substrate. In one aspect, conductive pad70and traces64and66can comprise the same Cu substrate from which traces64and66have been singulated or separated from pad70via etching or other removal method. After etching, an electrically insulating solder mask72can be applied such that it is at least partially disposed between conductive pad70and respective conductive traces64and66. Solder mask72can comprise a white material for reflecting light from LED device50. One or more layers of material can be disposed between LEDs22and conductive pad70. Similarly, one or more layers of material can be disposed over conductive traces64and66. For example and in one aspect, a first intervening layer or substrate of material68can be disposed between LEDs22and conductive pad70and disposed over traces64and66. First layer of material68can comprise a layer of reflective Ag or Ag-alloy material for maximizing brightness of light emitted from LED device50. That is, first layer of material68can comprise a Ag or Ag-containing substrate adapted to increase brightness of device50. One or more additional layers of material (not shown) can be disposed between first layer68and conductive pad70and/or first layer68and traces64and66, for example, a layer of Ni can be disposed therebetween for providing a barrier between the Cu of pad and traces70,64, and66and the Ag of layer68.

Notably, a protective layer P can be at least partially disposed over and/or adjacent to Ag components within device50, for example, over first layer68of material which can coat conductive pad70and traces64and68. Protective layer P can provide a barrier over the Ag coated components thereby preventing such components from being physically or electrically degraded via tarnishing, oxidizing, corroding, or other degrading phenomenon caused when harmful chemical, vaporous, or atmospheric complexes C permeate filling material58. As described earlier, complexes C such as sulfur, sulfides, sulfates, chlorine complexes, bromine complexes, NOR, oxygen, and/or moisture can damage Ag coatings or Ag coated components, such as layer68which can coat Cu components including pad70and/or traces64and66. As described earlier, protective layer P can comprise an inorganic coating or inorganic oxide coating such as a Si-containing inorganic oxide layer which can repel or prevent complexes C from reaching vulnerable components within LED device50as shown by the broken lines and arrows. As previously described, protective layer P can comprise an inorganic coating or inorganic oxide coating selected from the group consisting of, but not limited to, organosilicate glass, organosilicate solution, organosilicate dispersion, organosilicate sol-gel, Si-containing spin-on glass (SOG) materials, spin-on polymer materials, and/or spin-on dielectric materials. Protective layer P can comprise SOG materials optimized by implementing novel application and/or curing techniques. That is, SOG materials can be, but do not have to be applied by spin-on techniques. SOG materials can also be applied via novel application methods such as dispensing, dipping, painting, screen printing, brushing, and spraying such materials which achieve the unexpected result of protecting LED components within device50from undesirable chemical components or complexes C capable of permeating LED device50without cracking and/or shrinking, and while maintaining good adhesion within device50. Also of note, SOG materials can be cured via novel curing schedules including curing at temperatures that are less than approximately 300° C. such that LED device50and/or components within LED device50(e.g., retention material56or encapsulant) are not damaged by the curing temperature.

FIG. 4further illustrates a cross-section of submount52over which LEDs22can be mounted or otherwise arranged. Submount52can comprise, for example, conductive pad70, first and second conductive traces64and66, and solder mask72at least partially disposed between conductive pad70and each of conductive traces64and/or66. Conductive traces64,66and conductive pad70can be coated with a first layer68, for example Ag. Protective layer P can be disposed over Ag as shown, or similar to any of the embodiments illustrated inFIGS. 5 to 13. Submount52can further comprise a dielectric layer74, and a core layer76. Solder mask72can directly adhere to portions of dielectric layer74. For illustration purposes, submount52can comprise a MCPCB, for example, those available and manufactured by The Bergquist Company of Chanhassan, Minn. Any suitable submount52can be used, however. Core layer76can comprise a conductive metal layer, for example copper or aluminum. Dielectric layer74can comprise an electrically insulating but thermally conductive material to assist with heat dissipation through submount52.

As noted earlier, device50can comprise a package which does not require or use any secondary optics to keep harmful elements from degrading conductive pad70. Notably, devices, components and methods disclosed herein provide for improved or optimized chemical resistance and improved chemical properties where zero or minimum loss of brightness occurs, even in the presence of harmful chemicals and can be applicable to any SMD type device or multi-array device disclosed herein. Such improvements can prevent Ag coated components from tarnishing, darkening, corroding, or otherwise degrading.

As described earlier, protective layer P can least partially comprise an inorganic material for increasing chemical resistance of the substrate. Such inorganic material of protective layer P can comprise an inorganic coating, an inorganic film with an organic matrix material, and/or an inorganic oxide coating having a thickness ranging from approximately 1 nm to 100 μm. Any sub-range of protective layer P thickness between approximately 1 nm and 100 μm is also contemplated herein, for example, thicknesses ranging between approximately 10 nm and 50 nm; 50 nm and 200 nm; 200 nm and 400 nm; 400 and 600 nm; 600 and 800 nm; 800 nm and 1 μm; 1 μm and 5 μm; 5 μm and 10 μm; 10 μm and 50 μm; and 50 μm and 100 μm are contemplated. Protective layer P can also comprise a thickness ranging from approximately 1 nm to 100 nm, 100 nm to 500 nm, and 0.5 μm to 20 μm are also contemplated herein.

Of note, one or more additional processing techniques or steps can optionally be performed during manufacture of devices described herein for improving adhesion between one or more layers within the devices. Such optionally processing steps can be used and applied to devices previously shown and described, as well as those inFIGS. 5 through 13described hereinbelow. For example, such optional techniques can be performed to one or more surfaces prior to deposition or application of one or more adjacent surfaces within a device. Techniques and/or optional processing steps can be performed on surfaces or layers, such as, for example and without limitation, Cu surfaces (e.g., inner portion30of elements14,16, and/or18of device10and/or surfaces of conductive pad70, traces64and66of device50), Ag surfaces (e.g., outer portion32of elements14,16, and/or18of device10, layer of material68of device50), and/or surfaces of protective layer P. In one aspect, one or more of these surfaces can be physically, chemically, or thermally prepared or treated to improve adhesion between the treated surface and adjacent surface(s) or adjacent layer(s). Optional processing steps that are physical in nature can comprise, for example and without limitation, sandblasting, plasma etching, brushing, lapping, sanding, burnishing, grinding, and/or any suitable form of surface roughening (e.g., physically texturizing the surface) to improve adhesion between one or more layers or surfaces within devices shown and described herein. Optional processing steps that are chemical in nature can comprise, for example and without limitation, chemical etching, applying solvents, applying organic solvents, applying acids, applying bases, vapor degreasing, priming, or any suitable chemically process for treating a surface to improve adhesion between one or more layers or surfaces within devices shown and described herein. Optional thermal processing steps can comprise, without limitation, prebaking, preheating, or any suitable thermal treatment that improves adhesion between one or more layers or surfaces within devices shown and described herein.

FIGS. 5 to 13are cross-sections of previously described LED device10which illustrate various locations or placement of protective layer P within and/or over different surfaces of device10. The location of protective layer P shown and described inFIGS. 5 to 13are equally applicable to device50(FIGS. 3 and 4) as well as any other LED component or embodiment (e.g., downset seeFIG. 13, through-hole, TV backlighting downset component), however, for illustration purposes only device10has been illustrated in such numerous embodiments. At least one protective layer P can be used within the LED device for improving chemical resistance of the device by providing a barrier of protection against chemical complexes C (FIGS. 2, 4). In one aspect, protective layer P can prevent Ag components from tarnishing, corroding, darkening and/or degrading thereby retaining brightness and optical properties of LED device even in the presence of complexes C (FIGS. 2, 4).FIGS. 5 to 13illustrate a protective coating or layer P which can be applied directly and/or indirectly over the Ag coated thermal and electrical components14and16,18at different locations with respect to device components and/or at different stages of production of device10. The placement of protective layer P can be dictated by the order of processing steps. For example, if the LED chip22or wire bonds24are installed before protective layer P is applied, protective layer P will usually coat the LED chips22and wire bonds as well as the Ag surface. Other processing steps may involve the masking or removal of protective layer P. All processing sequences and therefore placements of protective layer P are contemplated and are not limited to such exemplary sequences and/or locations as described herein.

Two or more protective layers, for example, a first and a second protective layer, P1and P2, respectively, can be used within device10for protecting against harmful chemical complexes which may permeate device10and degrade components of device10(SeeFIG. 8). Initially of note, and for illustration purposes only, the number of protective layers shown herein may be limited to two, however, any suitable number of protective layers can be applied at any step in the production process and/or at any location within device10, and such application steps and/or locations are contemplated herein. As described earlier, protective layer P (and/or P1and P2,FIG. 8) can at least partially comprise inorganic material such as an inorganic coating, an inorganic film with an organic matrix material, and/or an inorganic oxide coating having a thickness ranging from approximately 1 nm to 100 μm. Any sub-range of thickness between approximately 1 nm and 100 μm is contemplated. Protective layer P can be delivered and/or applied in any form to device10, such as but not limited to application of a solution, dispersion, sol-gel, SOC material (e.g., in solution form), spin-on polymer material, spin-on dielectric material (e.g., as a flowable oxide) or combinations thereof. Protection layer P can provide protection against undesired chemicals, chemical vapors, and chemical complexes C (FIGS. 2, 4) serving as an anti-oxidation, anti-corrosion layer over Ag and Cu, and substrates containing such metals.

AsFIG. 5illustrates, protective layer P can be applied, deposited, or otherwise disposed over electrical and thermal elements16,18, and14before the processing step of molding the device body12about the leadframe components. That is, protective layer P can extend to a location at least partially within a portion of the molded plastic body12such that it contacts one or more surfaces of body12. In one aspect, protective layer P can be disposed between one or more portions of body12as illustrated. Protective layer P can also be disposed between LED22and outer portion32of thermal element14. As previously described, outer portion32can comprise a layer of Ag (or Ag-alloy coating or plating) over which protective layer P can provide a protective barrier for protecting against complexes which can tarnish, oxidize, or corrode the Ag. Protective layer P can retain optical properties (e.g., brightness) of device10despite exposure to undesired chemical complexes which may permeate the device. Protective layer P may also optionally be applied such that it fully extends over floor34of cavity26and within portions of body12such that layer P extends over isolating portions20of body as well as Ag coated components (e.g., over outer portions32of elements14,16, and18).

FIG. 6illustrates an embodiment of device10where protective layer P has been deposited after the processing step of molding the body12, but prior to the LED die attach step, wire bonding step, and/or application of encapsulant28step. Thus, protective layer P can extend to a location within device10that is below LED22and along at least a portion of cavity floor34. Protective layer P can extend between upper surfaces of thermal element14and LED22. In one aspect, protective layer P can be disposed over the entire surface of cavity floor34, thus, disposed over surfaces of each of thermal and electrical elements14,16, and18and isolating portions20of body12. In a further aspect, protective layer P can optionally extend along one or more side walls of reflector cavity26as indicated. In addition, since wire bonding to an inorganic protective layer P may be difficult, additional processing steps such as masking and/or etching protective layer P may be employed and are contemplated herein.

FIG. 7illustrates an embodiment of device10where protective layer P can be applied after the processing step of wire bonding but before the processing step of application of encapsulant28. In one aspect, protective layer P can at least partially coat surfaces of wire bonds24, LED22, walls of cavity26, cavity floor34, and surfaces of thermal element14and electrical elements16and18(e.g., outer portions32of elements14,16, and18).

FIG. 8illustrates an embodiment where more than one protective layer can be applied, for example, a first protective layer P1and a second protective layer P2. First and second protective layers P1and P2can be applied at any processing step during production of LED device10(and/or device50), thereby assuming the placement illustrated and described in any ofFIGS. 2, 4, and 5 to 13(e.g., the only difference being application of more than one protective layer P). Each of first and second protective layers P1and P2can comprise inorganic material incorporated into an inorganic coating, inorganic oxide coating, or Si-containing coating as previously described. Protective layers P1and P2can comprise any thickness ranging from approximately 1 nm to 100 μm. Thicknesses less than 1 nm and/or greater than 100 μm can also be used, however, where more than one layer is present. First and second layers P1and P2can be applied as shown over outer portions32of thermal and electrical elements14,16, and18before die attaching LED22. First and second layers P1and P2can optionally extend up side walls of reflector cavity26as shown.

FIG. 9illustrates another embodiment of device10, where protective layer P has been applied after the processing step of die attach but before the step of applying encapsulant28. That is, protective layer P can be located such that it extends about the side and upper surfaces of LED22, and over portions of wire bond24, where wire bond24attaches to LED22(e.g., at wire bond ball). Protective layer P can also be disposed entirely over floor34of cavity over outer portions32of elements14,16, and18as well as isolating portions20of body12. Protective layer P can optionally extend up side walls of cavity26. Notably, protective layer P can, but does not need to comprise a uniform thickness. For example, wetting properties of layer P tend to create thicker areas, or fillets around features within LED device10. For example, layer P may be thicker in areas T surrounding LED22as indicated. Thinner areas of protective layer P are also contemplated.

FIG. 10illustrates an embodiment of device10where protective layer P has been applied after die attachment of LED22but prior to application of encapsulant28. AsFIG. 10illustrates, protective layer P can be located and applied subsequently over a first layer80. First layer80can comprise any type of coating or layer, for example, an adhesion coating or layer, a light-affecting coating or layer, or another protective barrier coating or layer such as an inorganic coating or oxide. In one aspect, first layer80comprises a layer of light-affecting material such as a layer of encapsulant containing phosphor material that emits light of a desired color point when activated by light from the LED22. First layer80can be disposed between portions of LED22and protective layer P, between outer portions32of elements14,16, and18and protective layer P, and/or between isolating portions20of body12and protective layer P. In an alternative embodiment, LED chip22can comprise a horizontally structured (i.e., both contacts on the same side, a bottom side) chip that is directly attached (e.g., no wire bonds) to electrical elements16and18. That is, electrical contacts or bond pads (not shown) disposed on a bottom surface of LED22could directly attach to electrical elements16and18via electrically conductive die attach adhesive (e.g., silicone, epoxy, or conductive silver (Ag) epoxy) such that the electrical contacts of LED22electrically communicate directly to elements16and18without the need for wire bonds24. First layer80can then be applied over LED22and can comprise a layer of encapsulant containing phosphor. Protective layer P can then be applied over each of LED chip22and first layer80as indicated.

FIGS. 11 and 12illustrate further embodiments of device10, where protective layer P has been applied after and/or during the processing step of application (e.g., dispensing) of encapsulant28. For example, inFIG. 11, protective layer P can be disposed over an upper surface of encapsulant28. Protective layer P can optionally extend over external surfaces of device10, for example, over top surface40of body12. Protective layer P can be disposed at a location such that complexes C (FIG. 2) can be repelled before permeating any portion of encapsulant28.FIG. 12illustrates protective layer P applied during the processing step of application of encapsulant28. In this embodiment, protective layer P can be disposed between portions of encapsulant28, such that undesirable complexes C (FIG. 2) can be prevented from reaching Ag coated components (e.g., outer portion32of elements14,16, and18) thereby preventing any potential damage, corrosion, or darkening that may occur to the Ag components. That is, protective layer P can be disposed between layers or portions of encapsulant28or between two or more separate encapsulation steps. This can advantageously allow device10to incur approximately zero, or minimal, brightness loss during operation, even in the presence of harmful chemicals, chemical vapors, oxygen, or moisture.

FIG. 13illustrates a further embodiment of device10. Device10can comprise two electrical elements16and18to which LED22can electrically connect. Tab portions36and38can bend inwardly towards each other thereby adapting either a J-bend. In this embodiment, LED22can comprise a vertically structured device with a first electrical contact or bond pad on a bottom surface and a second electrical contact or bond pad on the opposing top surface. The first electrical contact can electrically and physically connect with first electrical element16via a die attach adhesive (e.g., silicone, flux, solder, epoxy, etc.) and second electrical contact can electrically and physically connect to second electrical element18via wire bond24. In this embodiment, LED device10comprises a downset or recessed type of package where LED22and/or at least a first electrical element can be on a different plane than other components of the LED package or device (e.g., on a different plane from second electrical element18). In this embodiment, protective layer P can be applied in any of the locations shown inFIGS. 5-12. For illustrations purposes, protective layer P is shown as applied before attaching and wire bonding LED22. However, any suitable sequence for placing and/or location of protective layer P is contemplated, for example, along one or more sidewalls of device10and/or applied in combination with other layers. Protective layer P can be applied such that it is disposed over a portion of body12(e.g., between 16 and 18) and can be subsequently removed as shown via optional masking and/or etching steps if desired.

Embodiments of the present disclosure shown in the drawings and described above are exemplary of numerous embodiments that can be made within the scope of the appended claims. It is contemplated that the configurations of LED devices optimized for chemical resistance and methods of making the same can comprise numerous configurations other than those specifically disclosed, including combinations of those specifically disclosed.