Patent Description:
Semiconductor light-emitting devices including light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), and edge emitting lasers are among the most efficient light sources currently available. Materials systems currently of interest in the manufacture of high-brightness light emitting devices capable of operation across the visible spectrum include Group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also referred to as III-nitride materials. Typically, III-nitride light emitting devices are fabricated by epitaxially growing a stack of semiconductor layers of different compositions and dopant concentrations on a sapphire, silicon carbide, III-nitride, or other suitable substrate by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. The stack often includes one or more n-type layers doped with, for example, Si, formed over the substrate, one or more light emitting layers in an active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, Mg, formed over the active region. Electrical contacts are formed on the n- and p-type regions.

<FIG> illustrate a method of forming a phosphor-converted LED, described in more detail in <CIT>. In <FIG>, a base <NUM> is provided and light emitting elements (LEEs) <NUM> are placed on or adhered to base <NUM> with contacts <NUM> adjacent to base <NUM>. The LEEs <NUM> have a spacing <NUM> between adjacent elements. Base <NUM> may also be referred to as a "mold substrate. " In one embodiment, base <NUM> includes or consists essentially of an adhesive film or tape. In some embodiments, base <NUM> includes or consists essentially of a material to which has a relatively low adhesion to phosphor <NUM>, that is, it permits removal of cured phosphor <NUM> from base <NUM>.

In <FIG>, barriers <NUM> are formed. Barriers <NUM> are shown as perpendicular or substantially perpendicular to a surface <NUM>. The spacing <NUM> between adjacent LEEs <NUM> may be adjusted to control the width of cured phosphor <NUM> around the sides of LEEs <NUM> as shown in <FIG>. Spacing <NUM> between LEEs <NUM> is approximately determined by the sum of twice the desired sidewall thickness of the phosphor and the kerf (where the kerf is the width of the region removed during the singulation process of finished dies <NUM>, for example identified as kerf <NUM> in <FIG>. The thickness of cured phosphor <NUM> over the LEEs <NUM> may be controlled by controlling a thickness <NUM> of phosphor <NUM> that is formed or dispensed as shown in <FIG>. Thickness <NUM> of cured phosphor <NUM> over LEE <NUM> is given approximately by the thickness of dispensed phosphor, <NUM> less the thickness <NUM> of the LEE. Phosphor <NUM> includes or consists essentially of a phosphor and a binder. Phosphor <NUM> is contained or bounded by surface <NUM> of base <NUM> and optional sides or barriers <NUM>. Phosphor <NUM> has a bottom surface or face <NUM> and a top surface or face <NUM>, which are substantially parallel to each other.

Phosphor <NUM> is then cured, producing cured phosphor <NUM> as shown in <FIG>.

In <FIG>, white dies <NUM> are separated or singulated from the structure shown in <FIG>. White dies <NUM> may have a size ranging from about <NUM> to about <NUM>.

<CIT> describes a light emitting device in which the color dispersion of white light is minimized with respect to the emitting direction of light and a method for manufacturing thereof. Said light emitting element has first and second main surfaces opposed to each other; a wavelength converting part formed on the first main surface of the light emitting element; first and second terminals formed on the second main surface of the light emitting element; and a reflecting part formed to cover at least sides of the light emitting element and sides of the wavelength converting part.

<CIT> discloses a light emitting device with a light emitting element having an upper surface that forms a light extracting surface, a translucent material with upper and lower surfaces where light emitted from the light emitting element is incident on the lower surface and emitted to the outside through the upper surface, and a light reflecting resin that covers at least one part of the translucent material.

<CIT> describes a semiconductor structure including a light emitting layer disposed between an n-type region and a p-type region and the semiconductor structure being optically coupled to a compound substrate including a host and a ceramic layer including a luminescent material. Therein, the p-type region is below the n-type region, such that contacts connect to the n-type region and contacts connect to the p-type region. After the contacts are formed and a wafer of devices is diced into individual dice, one or more dice is being connected to a mount.

Document <CIT> discloses a light emitting device providing a colour conversion plate containing different phosphors regions and outputs fluorescence. The colour conversion plate can have multiple first regions containing the first phosphor on a light emitting element side, being arranged with a predetermined spacing therebetween, and second regions containing the second phosphor on the upper surface, being arranged with a predetermined spacing therebetween. Side surfaces of the semiconductor light emitting element and the colour conversion plate are surrounded by an optical reflection frame.

Document <CIT> discloses a light emitting apparatus and a production method. The apparatus includes a light emitting device, a transparent member receiving incident light emitted from the device, and a covering member. The transparent member is formed of an inorganic material light conversion member including an externally exposed emission surface, and a side surface contiguous to the emission surface. The covering member contains a reflective material, and covers at least the side surfaces of the transparent member. Only the emission surface serves as the emission area of the apparatus.

It is an object of the invention to provide a wavelength converted semiconductor light emitting device with a small source size.

A lighting structure according to the invention is defined in claim <NUM> and includes a semiconductor light emitting device and a flat wavelength converting element attached to the semiconductor light emitting device, wherein an area of the wavelength converting element is greater than an area of a top surface of the semiconductor light emitting device. The flat wavelength converting element includes a wavelength converting layer for absorbing light emitted by the semiconductor light emitting device and emitting light of a different wavelength. The flat wavelength converting element further includes a transparent layer. The wavelength converting layer is formed on the transparent layer. The lighting structure further comprises a reflective material disposed on the sides of the semiconductor light emitting device.

A method according to the invention is defined in claim <NUM> and includes forming a wavelength converting element including a wavelength converting layer disposed on a transparent layer. The wavelength converting element is then attached to a wafer of semiconductor light emitting devices. The wavelength converting element and the wafer of semiconductor light emitting devices are then diced to form a plurality of lighting elements. The plurality of lighting elements are then disposed on a handling substrate. A reflective material is disposed between the plurality of lighting elements.

Another method according to the invention is defined in claim <NUM> and includes forming a wavelength converting element, the wavelength converting element including a wavelength converting layer disposed on a transparent layer, wherein the wavelength converting element is rigid. The wavelength converting element is then attached to a plurality of diced semiconductor light emitting devices disposed on a handling substrate. The wavelength converting element is then diced to form a plurality of lighting elements. After said dicing, disposing the plurality of lighting elements on a handling substrate and disposing a reflective material between the plurality of lighting elements.

Because the phosphor extends over the edges of the LEE in <FIG>, the devices illustrated in <FIG> have a larger source size than the light emitting diode without the phosphor layer. Because of the large source size, the devices illustrated in <FIG> may be less bright than the same amount of light emitted in a smaller source size. The large source size makes the devices illustrated in <FIG> undesirable in some applications.

Embodiments of the invention include wavelength converted devices with a relatively small source size, which may be inexpensive to manufacture.

Though in the examples below the semiconductor light emitting device are III-nitride LEDs that emits blue or UV light, semiconductor light emitting devices besides LEDs such as laser diodes and semiconductor light emitting devices made from other materials systems such as other III-V materials, III-phosphide, III-arsenide, II-VI materials, ZnO, or Sibased materials may be used.

<FIG> illustrates a III-nitride LED <NUM> that may be used in embodiments of the present invention. Any suitable semiconductor light emitting device may be used and embodiments of the invention are not limited to the device illustrated in <FIG>. The device of <FIG> is formed by growing a III-nitride semiconductor structure on a growth substrate <NUM> as is known in the art. The growth substrate is often sapphire but may be any suitable substrate such as, for example, SiC, Si, GaN, or a composite substrate. A surface of the growth substrate on which the III-nitride semiconductor structure is grown may be patterned, roughened, or textured before growth, which may improve light extraction from the device. A surface of the growth substrate opposite the growth surface (i.e. the surface through which a majority of light is extracted in a flip chip configuration) may be patterned, roughened or textured before or after growth, which may improve light extraction from the device.

The semiconductor structure includes a light emitting or active region sandwiched between n- and p-type regions. An n-type region <NUM> may be grown first and may include multiple layers of different compositions and dopant concentration including, for example, preparation layers such as buffer layers or nucleation layers, and/or layers designed to facilitate removal of the growth substrate, which may be n-type or not intentionally doped, and n- or even p-type device layers designed for particular optical, material, or electrical properties desirable for the light emitting region to efficiently emit light. A light emitting or active region <NUM> is grown over the n-type region. Examples of suitable light emitting regions include a single thick or thin light emitting layer, or a multiple quantum well light emitting region including multiple thin or thick light emitting layers separated by barrier layers. A p-type region <NUM> may then be grown over the light emitting region. Like the n-type region, the p-type region may include multiple layers of different composition, thickness, and dopant concentration, including layers that are not intentionally doped, or n-type layers.

After growth, a p-contact is formed on the surface of the p-type region. The p-contact <NUM> often includes multiple conductive layers such as a reflective metal and a guard metal which may prevent or reduce electromigration of the reflective metal. The reflective metal is often silver but any suitable material or materials may be used. After forming the p-contact <NUM>, a portion of the p-contact <NUM>, the p-type region <NUM>, and the active region <NUM> is removed to expose a portion of the n-type region <NUM> on which an n-contact <NUM> is formed. The n- and p-contacts <NUM> and <NUM> are electrically isolated from each other by a gap <NUM> which may be filled with a dielectric such as an oxide of silicon or any other suitable material. Multiple n-contact vias may be formed; the n- and p-contacts <NUM> and <NUM> are not limited to the arrangement illustrated in <FIG>. The n- and p-contacts may be redistributed to form bond pads with a dielectric/metal stack, as is known in the art.

In order to form electrical connections to the LED <NUM>, one or more interconnects <NUM> and <NUM> are formed on or electrically connected to the n- and p-contacts <NUM> and <NUM>. Interconnect <NUM> is electrically connected to n-contact <NUM> in <FIG>. Interconnect <NUM> is electrically connected to p-contact <NUM>. Interconnects <NUM> and <NUM> are electrically isolated from the n- and p-contacts <NUM> and <NUM> and from each other by dielectric layer <NUM> and gap <NUM>. Interconnects <NUM> and <NUM> may be, for example, solder, stud bumps, gold layers, or any other suitable structure. The semiconductor structure, n- and p-contacts <NUM> and <NUM>, and interconnects <NUM> and <NUM> are shown in the following figures as LED structure <NUM>.

The substrate <NUM> may be thinned or entirely removed. In some embodiments, the surface of substrate <NUM> exposed by thinning is patterned, textured, or roughened to improve light extraction.

Many individual LEDs are formed on a single wafer then diced from a wafer of devices. Any suitable device may be used. The invention is not limited to the particular LED illustrated in <FIG>. The combined thickness of substrate <NUM> and LED structure <NUM> may be at least <NUM> in some embodiments, no more than <NUM> in some embodiments, at least <NUM> in some embodiments, and no more than <NUM> in some embodiments. The substrate <NUM> may be no more than <NUM> thick in some embodiments, no more than <NUM> thick in some embodiments, and at least <NUM> thick in some embodiments.

Separate from the LEDs, a wavelength converting element is formed, as illustrated in <FIG>. The wavelength converting element includes a support substrate <NUM> and a wavelength converting layer <NUM>. The wavelength converting element is formed on a wafer scale, meaning that the wavelength converting element illustrated in <FIG> can be thought of as a wafer of many individual wavelength converting elements.

In some embodiments, the support substrate <NUM> becomes part of the light emitting device. In these embodiments, the support substrate <NUM> may be transparent to the light emitted by the LED and/or the light emitted by the phosphor. The support substrate may also be sufficiently robust to withstand any processing steps that occur after attaching the wavelength converting element to an LED and to withstand the operating conditions of the light emitting device, and may be formed of a material that is optically suitable for the light emitting device. The support substrate <NUM> may be, for example, glass, silicone, polymer, polyethylene terephthalate (PET), or any other suitable material.

In some embodiments, the support substrate <NUM> is removed, and does not become part of the light emitting device. In these embodiments, the support substrate <NUM> material is selected for cost and suitability for the processing steps to which the support substrate <NUM> is subjected. If the support substrate <NUM> is removed after processing, the support substrate need not be transparent.

The wavelength converting layer <NUM> includes a wavelength converting material which may be, for example, conventional phosphors, organic phosphors, quantum dots, organic semiconductors, II-VI or III-V semiconductors, II-VI or III-V semiconductor quantum dots or nanocrystals, dyes, polymers, or other materials that luminesce. The wavelength converting material absorbs light emitted by the LED and emits light of one or more different wavelengths. Unconverted light emitted by the LED is often part of the final spectrum of light extracted from the structure, though it need not be. Examples of common combinations include a blue-emitting LED combined with a yellow-emitting wavelength converting material, a blue-emitting LED combined with green- and red-emitting wavelength converting materials, a UV-emitting LED combined with blue- and yellow-emitting wavelength converting materials, and a UV-emitting LED combined with blue-, green-, and red-emitting wavelength converting materials. Wavelength converting materials emitting other colors of light may be added to tailor the spectrum of light extracted from the structure.

The wavelength converting layer <NUM> may include a transparent material such as silicone that is mixed with the wavelength converting material. The wavelength converting layer <NUM> is formed and attached to the support substrate <NUM> by any suitable technique. In some embodiments, a wavelength converting layer <NUM> that is a wavelength converting material mixed with a transparent material is dispensed, screen printed, stenciled, spin-casted, laminated, molded or otherwise formed on a glass support substrate <NUM>. The wavelength converting layer <NUM> may be formed by a process that includes curing, for example by exposing the wavelength converting layer to light and/or to elevated temperature. For example, a laminated wavelength converting layer <NUM> may be cured at a temperature greater than <NUM> in some embodiments and less than <NUM> in some embodiments. In some embodiments the wavelength converting layer <NUM> is partially cured when it is disposed on the support substrate, and partially cured during a later processing step such as, for example, when it is attached to light emitting devices.

The wavelength converting layer <NUM> may have a thickness of at least <NUM> in some embodiments, no more than <NUM> in some embodiments, at least <NUM> in some embodiments, and no more than <NUM> in some embodiments. The support substrate <NUM> may be thinner than the wavelength converting layer <NUM> in some embodiments, though this is not required. A transparent support substrate <NUM> such as glass may have a thickness of at least <NUM> in some embodiments, at least <NUM> in some embodiments, no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, and no more than <NUM> in some embodiments.

In <FIG>, the wavelength converting element illustrated in <FIG> is attached to a wafer of LEDs before the LED wafer is diced. The surface of the wavelength converting layer <NUM> opposite the support substrate <NUM> is attached to the surface of substrate <NUM> opposite the LED structures 12A - 12F. The wavelength converting element may be attached to the LED wafer by any suitable technique, such as gluing with silicone or any other suitable adhesive, or heating the wavelength converting element such that the transparent material in the wavelength converting layer <NUM> adheres to the substrate <NUM>.

The structure illustrated in <FIG> is then diced into individual LEDs, or groups of LEDs. The structure illustrated in <FIG> is diced for example by cutting through the support substrate <NUM>, the wavelength converting layer <NUM>, the substrate <NUM>, and a portion of the LED structures 12A-12F in the regions <NUM> illustrated in <FIG>. The layers may be cut together in a single cutting step, or individual layers may be separately cut in multiple cutting steps. For example, the substrate <NUM> and LED structure <NUM> may be cut by, for example, scribing and breaking, before or after the support substrate <NUM> and wavelength converting layer <NUM> are cut by, for example, sawing. Any suitable cutting technique(s) may be used such as, for example, sawing, laser scribing, scribe-and-break, blade cutting, or any other suitable process. Though only six individual LEDs are illustrated in <FIG>, an LED wafer may include many more individual LEDs.

In <FIG>, the LEDs that were diced in <FIG> are placed on a handling substrate <NUM>. Only a portion of a single handling substrate <NUM> including three LEDs 38A, 38B, and 38C is illustrated in <FIG>. The processes illustrated in <FIG> may be undertaken at a scale where hundreds or thousands of LEDs are disposed on a single handling substrate <NUM>. The handling substrate <NUM> is any suitable structure from which the LEDs may be later removed, such as, for example, wafer handling tape. The LEDs may be spaced at least <NUM> apart in some embodiments, at least <NUM> apart in some embodiments, at least <NUM> apart in some embodiments, and no more than <NUM> apart in some embodiments.

A reflective material <NUM> is disposed over LEDs 38A, 38B, and 38C. Reflective material may be, for example, white or reflective particles such as TiO<NUM> disposed in a transparent material. The reflective particles and the transparent material may form a contrast in index of refraction, which scatters and/or reflects light. The reflective material may be formed by any suitable technique; for example the reflective material may be molded, dispensed, laminated, or otherwise disposed over the LEDs.

In some embodiments, as illustrated in <FIG>, excessive <NUM> reflective material <NUM> is formed over the tops of LEDs 38A, 38B, and 38C. The excessive material <NUM> illustrated in <FIG> may be removed, as illustrated in <FIG>. The excessive material <NUM> may be removed by any suitable technique, including dry bead blasting, wet bead blasting, grinding, polishing, mechanical techniques, or etching. After the excessive material is removed, the tops <NUM> of LEDs 38A, 38B, and 38C are exposed. The top surface <NUM> is a surface of support substrate <NUM> opposite the wavelength converting layer <NUM>. In some embodiments, the technique for removing excessive material <NUM> is selected to roughen, polish, texture, or pattern the top surface <NUM>, for example to improve light extraction from the device. Alternatively, the top surface may be roughened, polished, textured, or patterned in a separate processing step.

In some embodiments, after removing the excessive material <NUM> shown in <FIG>, the top surface <NUM> of reflective material <NUM> between LEDs is at the same level as the top surface of LEDs 38A, 38B, 38C. In some embodiments, as illustrated in <FIG>, after removing the excessive reflective material, the top surface <NUM> of reflective material <NUM> between LEDs is at a different level than the top surface of LEDs 38A, 38B, 38C. In particular, the top surface <NUM> of reflective material <NUM> between LEDs may be below the top surface of LEDs 38A, 38B, 38C. Reducing the thickness of the reflective material to below the top surface of the LEDs may be useful, for example, in embodiments as described below where the support substrate <NUM> is removed after forming the reflective material.

The LEDs may then be separated into individual devices or groups of devices by cutting the reflective material between LEDs, for example in regions <NUM> illustrated in <FIG>. The LEDs may then be removed from the handling substrate <NUM> by any technique suitable to the particular handling substrate used. Because reflective material <NUM> is disposed on the sides of the LED, light is extracted from the final device primarily through the top surface of the LED (the surface of the support substrate <NUM> of the wavelength converting member in the embodiment illustrated in <FIG>). The thickness of the reflective material on the sides of the LEDs after cutting may be at least <NUM> in some embodiments, at least <NUM> in some embodiments, at least <NUM> in some embodiments, and no more than <NUM> in some embodiments.

In some embodiments, as illustrated in <FIG>, <FIG>, the wavelength converting element wafer illustrated in <FIG> is attached to a group of LEDs after the LEDs are separated from a wafer of LEDs. In these embodiments, the LED wafer is diced before the wavelength converting element wafer. It may be difficult to simultaneously dice the wavelength converting element and the LED wafer, as described above in reference to <FIG>.

In <FIG>, previously diced LEDs are disposed on a handling substrate <NUM>. Only a portion of a single handling substrate <NUM> including four LEDs 52A, 52B, 52C, and 52D is illustrated in <FIG>. The processes illustrated in <FIG> may be undertaken at a scale where hundreds of LEDs are disposed on a single handling substrate <NUM>. The handling substrate <NUM> is any suitable structure from which the LEDs may be later removed, such as, for example, wafer handling tape.

A wavelength converting element wafer, as described above in <FIG>, is attached to a top surface of the LEDs by any appropriate material or technique. The wavelength converting element wafer may be attached such that the wavelength converting layer <NUM> is disposed between the LEDs and the support substrate <NUM>, as illustrated in <FIG>, though the opposite orientation, where the support substrate <NUM> is disposed between the LEDs and the wavelength converting layer <NUM>, is also possible.

The wavelength converting element wafer is then cut in regions <NUM> to form single devices or groups of devices. Cutting the wavelength converting element wafer between two LEDs 52A and 52B is illustrated in <FIG>.

In a completed device, the wavelength converting member over a single LED is preferably as close as possible to the size of the top surface of the LED, in order to limit the source size and thereby improve the efficiency of the device. Exemplary LEDs 52A and 52Bare therefore spaced as close together on handling substrate <NUM> as possible. The spacing of LEDs 52A and 52B may be determined by the width of the kerf <NUM> resulting from cutting the wavelength converting element, and the tolerance of the wavelength converting element cutting operation.

The width of the kerf may vary depending on the cutting technique used. A kerf <NUM> formed by, for example, sawing, may be no more than <NUM> wide in some embodiments, no more than <NUM> wide in some embodiments, no more than <NUM> wide in some embodiments, and at least <NUM> wide in some embodiments.

The spacing <NUM> between neighboring devices may be no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, and at least <NUM> in some embodiments. The overhang <NUM>, or the length that the wavelength converting member extends out beyond the LED after cutting, may be no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, no more than <NUM> in some embodiments, and at least <NUM> in some embodiments.

As illustrated in <FIG>, the wavelength converting layer <NUM> over each LED is substantially flat in that it does not extend down over the sides of the LED. According to the invention, the area of the wavelength converting layer is larger than the area of the top surface of the LED. The area of the wavelength converting layer may be at least <NUM> % of the area of the top surface of the LED in some embodiments, at least <NUM> % of the area of the top surface of the LED in some embodiments, no more than <NUM> % of the area of the top surface of the LED in some embodiments, no more than <NUM> % of the area of the top surface of the LED in some embodiments, and no more than <NUM> % of the area of the top surface of the LED in the invention.

In <FIG>, after cutting the wavelength converting element wafer as illustrated in <FIG> to form individual LEDs or groups of LEDs, the LEDs 60A, 60B and 60C are removed from the handling substrate <NUM> and placed on a different handling substrate <NUM>. The different handling substrate <NUM> may be any suitable material and may be the same type of handling substrate as handling substrate <NUM>, such as, for example, wafer handling tape. Alternatively, the LEDs may be left on the handling substrate <NUM> illustrated in <FIG>, which may be stretched to space the LEDs further apart. The LEDs in <FIG> may be spaced at least <NUM> apart in some embodiments, at least <NUM> apart in some embodiments, at least <NUM> apart in some embodiments, and no more than <NUM> apart in some embodiments.

A reflective material <NUM> is molded over the LEDs, as described above in reference to <FIG>.

In <FIG>, excessive reflective material over the tops of the LEDs is removed, as described above in reference to <FIG>. As described above in reference to <FIG>, after the excessive material is removed, the tops <NUM> of LEDs 60A, 60B, and 60C are exposed. The top surface <NUM> is a surface of support substrate <NUM> opposite the wavelength converting layer <NUM>. In some embodiments, the technique for removing excessive reflective material is selected to roughen, polish, texture, or pattern the top surface <NUM>, for example to improve light extraction from the device.

In some embodiments, after removing the excessive reflective material, the top surface <NUM> of reflective material <NUM> between LEDs is at the same level as the top surface of LEDs 60A, 60B, 60C. In some embodiments, as illustrated in <FIG>, after removing the excessive reflective material, the top surface <NUM> of reflective material <NUM> between LEDs is at a different level than the top surface <NUM> of LEDs 60A, 60B, 60C. In particular, the top surface <NUM> of reflective material <NUM> between LEDs may be below the top surface <NUM> of LEDs 60A, 60B, 60C. Reducing the thickness of the reflective material to below the top surface of the LEDs may be useful, for example, in embodiments as described below where the support substrate <NUM> is removed after forming the reflective material.

The reflective material may be cut in regions <NUM> to form individual LEDs or groups of LEDs, then the devices are removed from the handling substrate <NUM>, as described above in reference to <FIG>.

<FIG> illustrates a device, which is not an embodiment of the present invention, where the support substrate <NUM> is removed from the wavelength converting layer <NUM>. In the structure illustrated in <FIG>, after forming the reflective material and removing excess reflective material, but before cutting the reflective material to form individual LEDs or groups of LEDs illustrated in either <FIG> or <FIG>, the support substrate <NUM> is removed from the devices.

In embodiments where the support substrate is removed, the support substrate may be a material that is selected for ease of removal. For example, the support substrate may be PET. A layer of adhesive such as a silicone adhesive or a thermal release adhesive may be disposed between the wavelength converting layer <NUM> and the support substrate <NUM> when the wavelength converting element illustrated in <FIG> is formed.

The support substrate pieces <NUM> illustrated in <FIG> or <FIG> may be removed by, for example, tape-to-tape transfer, thermal release, or any other suitable technique, resulting in the structure illustrated in <FIG>.

After removing the support substrate, the top surface <NUM> of each of the three LEDs 72A, 72B, and 72C is a surface of the wavelength converting layer <NUM>. The surface of wavelength converting layer <NUM> may be textured, patterned, or roughened, for example to improve light extraction, during or after the removal of the support substrate. During the removal of excess reflective material, the reflective material may be thinned such that after removing the support substrate, the top surface <NUM> of the LEDs is at substantially the same level as the top surface <NUM> of the reflective material <NUM>, though this is not required - the top surfaces <NUM> of the LEDs may be above or below the top surface <NUM> of the reflective material.

After removing the support substrates, the reflective material between LEDs is cut in regions <NUM>, to separate the devices into individual LEDs or groups of LEDs.

Claim 1:
A lighting structure comprising:
a semiconductor light emitting device (<NUM>) on a substrate (<NUM>); and
a flat wavelength converting element attached to the substrate (<NUM>) opposite to the semiconductor light emitting device (<NUM>), an area of the wavelength converting element being greater but no more than <NUM>% than an area of a top surface of the semiconductor light emitting device (<NUM>) and the substrate (<NUM>);
the flat wavelength converting element comprising:
a wavelength converting layer (<NUM>) attached to the substrate (<NUM>) for absorbing light emitted by the semiconductor light emitting device (<NUM>) and emitting light of a different wavelength; and
a transparent layer (<NUM>) attached to the wavelength converting layer (<NUM>) opposite to the substrate (<NUM>) such that the transparent layer (<NUM>) forms the top surface (<NUM>) of the lighting structure, wherein the wavelength converting layer (<NUM>) is formed on the transparent layer (<NUM>),
the lighting structure further comprising a reflective material (<NUM>, <NUM>) disposed on the sides of the semiconductor light emitting device (<NUM>),
wherein the reflective material (<NUM>) covers the side surfaces of the semiconductor light emitting device (<NUM>), the substrate (<NUM>) and the wavelength converting layer (<NUM>), wherein the top surface (<NUM>) of the reflective material (<NUM>) is below the top surface (<NUM>) of the transparent layer (<NUM>).