CN104904010B - Luminescent device including filter and protective layer - Google Patents

Abstract

Method according to an embodiment of the invention is attached to base including offer（62）Multiple LED（60）.By filter（102）It is attached at least one in the multiple LED.Protective layer is formed above the filter（104）.Reflecting layer is formed above the base（74）.Remove the part in the reflecting layer being placed in above the protective layer.

Description

Luminescent device including filter and protective layer

Technical field

The present invention relates to the luminescent device with filter and protective layer.

Background technology

Including light emitting diode（LED）, resonator light emitting diode（RCLED）, vertical cavity laser diodes（VCSEL）With Light emitting semiconductor device including edge emitter laser is one of currently available most efficient light source.Can be across can in manufacture Seeing the material system of current interest in the high brightness luminescent device that spectrum is operated includes Group III-V semiconductor, special Binary, ternary and the quaternary alloy of the galliums of III- nitride materials, aluminium, indium and nitrogen are not also known as.Generally, it is organic by metal Thing chemical vapor deposition（MOCVD）, molecular beam epitaxy（MBE）Or other epitaxy technologies pass through in sapphire, silicon carbide, III- Nitrogen or the stacking of other suitable substrate Epitaxial growth different components and the semiconductor layer of doping concentration light to make III- nitrogen Device.The stacking usually includes one or more n-layers doped with the Si for example formed above substrate, formed at this One or more of active area luminescent layer is in above n-layer or multiple n-layers, and it is active at this doped with for example being formed One or more p-type layers of Mg above area.Electric contact is formed in these n-types and p-type area.

Fig. 1 illustrates in US 7256483 flip-chip LED in greater detail.The LED includes n-layer 16, active Layer 18 and is grown in sapphire growth substrate（It is not shown）On p-type layer 20.The part of P layers 20 and active layer 18 is in LED shapes It is etched into during process, and metal 50（Metal layer adds jointing metal）With on the same side of p- contacting metals 24 Contact n-layer 16.Underfill material 52 can be deposited in the space below LED to reduce the thermal gradient across LED, increase LED The mechanical strength of annex between package substrate, and prevent pollutant from contacting LED materials.By n- metals 50 and p- metals 24 The pad 22A and 22B being joined respectively in package substrate 12.Using via 28A and 28B and/or metal wire by package substrate 12 Engagement pad 22A and 22B be connected to can welding electrode 26A and 26B.Remove growth substrates, the surface of exposing n-type layer 16.It is such as logical Cross and carry out optical electro-chemistry etching using KOH solutions to make the surface roughening to improve light extraction.

The content of the invention

It is an object of the invention to provide the luminescent device with filter.The filter is protected by protective layer.

Method according to an embodiment of the invention includes providing the multiple LED for being attached to base.Filter is attached to institute State at least one in multiple LED.Protective layer is formed above the filter.Reflecting layer is formed above the base.Go Except the part in the reflecting layer being placed in above the protective layer.

Embodiments of the invention include the multiple LED for being attached to base.Filter is placed in above LED.By hyaline layer It is placed in above filter.Reflecting material is placed between adjacent LED.

Brief description of the drawings

Fig. 1 illustrates the flip-chip LED with roughening top surface.

Fig. 2 is disposed upon the top view of one group of LED on base.

Fig. 3 is disposed upon the section view of the LED on base.

Fig. 4 is disposed upon the section view of the filter on wavelength conversion layer.

Fig. 5 illustrates the square structure into Fig. 4 after protective layer on the filter.

Fig. 6 is illustrated in unification（singulation）Fig. 5 structure afterwards.

Fig. 7 is attached to the section view of the LED illustrated in Fig. 3 Fig. 6 structure.

Fig. 8 illustrates the structure of Fig. 7 after Fig. 7 superstructure formation reflecting layer.

Fig. 9 illustrates the structure of Fig. 8 after the thinning top surface to expose protective layer in reflecting layer is made.

Figure 10 is disposed upon the section view of the smooth layer between filter and wavelength conversion layer.

Embodiment

In order to meet that, for the specification for application, the light that filtering LED is launched is sometimes necessary.In the reality of the present invention Apply in example, filter is placed in the light path that LED is launched.Can on the filter it is square into protective layer with LED's Ambient light filter during processing and/or operation.Although light emitting semiconductor device is transmitting blue light or UV light in following example III- nitrogen LED, but light emitting semiconductor device in addition to the LED of such as laser diode can be used and by such as Other materials of other III-V materials, III- phosphides, III- arsenides, II-VI material, ZnO or the material based on Si etc Light emitting semiconductor device obtained by material system.

Fig. 2 is attached to one group of LED 60 of base top view.In fig. 2, it is illustrated that base is attached to 2x2 arrays 62 four LED 60.As indicated by the application, can suitably it be arranged single led or any number of LED with any 60 are attached to base 62.In certain embodiments, power is supplied to LED 60 using the joint sheet 72 on base 62.

Can for example be configured to launch falling for most of light from the top surface of the LED with any LED 60 in figure below Cartridge chip device.Suitable LED 60 example is illustrated in Fig. 1, but can use any suitable LED.In order to III- nitrogen LED are formed, as it is known in the art, growing III- nitrogen semi-conductor structures first in growth substrates.Growth substrates Can be any suitable substrate, such as sapphire, SiC, Si, GaN or compound substrate.Semiconductor structure includes being clipped in n Luminous zone or active area between type area and p-type area.Can growing n-type area, and it can include different component and mix first Multiple layers of miscellaneous concentration, such as the plurality of layer include such as cushion or nucleating layer, and/or are designed to promote growth substrates The preparation layer of the layer of removal etc（The preparation layer can be n-type or unintentionally adulterate）, and efficiently send out for luminous zone The n-type penetrating the desired particular optical of light, material or electrical properties and design or even p-type device layer.It is raw above n-type area Long luminous zone or active area.The example of suitable luminous zone includes single thick or thin luminescent layer, or including by barrier layer Multiple quantum well radiation areas of the multiple thin or thick luminescent layer separated.It is then possible to p-type is grown above luminous zone Area.Similar to n-type area, p-type area can include multiple layers of different component, thickness and doping concentration, and the plurality of layer has including non- The layer or n-layer of meaning doping.The gross thickness of all semi-conducting materials is less than 10 μm and one in certain embodiments in device It is less than 6 μm in a little embodiments.In certain embodiments, p-type area is grown first, followed by active area and n-type area.

Metal p contacts are formed in p-type area.If most of be just exported by the surface relative with p contacts is partly led Body structure（Such as in flip chip devices）, then p contacts can be reflexive.Half can be made by being operated by standard lithographic Conductor structure is patterned and the semiconductor structure is etched to remove a part for the whole thickness of p-type area and luminous zone A part for whole thickness is to form the table top on the surface for exposing the n-type area for being formed on metal n contacts, to form upside-down mounting core Piece device.Table top and p contacts and n contacts can be formed in any suitable manner.Form table top and p contacts and n contacts It is well known to those skilled in the art.

Fig. 3 is attached to the section view of four LED 60 of base 62 simplification.LED can be 2x2 arrays, linear battle array Row or any other part suitably arranged.It can be installed on single-base 62 more more or less than illustrated four LED.P contacts and n contacts, gold stud bump can be passed through（gold stud bump）Or any other suitable connection mechanism will LED 60 is connected to base 62.Can be by the underfill of such as epoxy resin, silicones or any other suitable material etc In any space below material injection LED, between LED 60 and base 62.Such as removing the place later of growth substrates etc During managing step, base 62 and underfill can mechanically support semiconductor structure.Any suitable base can be used.Close The example of suitable base includes the insulation of the conductive via with being used to be formed to the electrical connection of semiconductor structure or semi-insulating chip （Such as silicon wafer or ceramic wafers）, metal structure or any other suitable base.In certain embodiments, in semiconductor junction Thick metal bond pads are formed on structure to support semiconductor structure during the processing of growth substrates etc is such as removed.Can be Growth substrates partly or are generally removed before or after LED 60 is attached into base 62, or growth substrates can leave A part as device.The semiconductor structure exposed by removing growth substrates can be roughened, pattern or line Physics and chemistry is to improve light extraction.

During with the process phase independence illustrated in Fig. 3, Wavelength transformational structure is prepared, as illustrated in Fig. 4,5 and 6 's.

In Fig. 4, light filter layer 102 is formed on Wavelength transformational structure 100.Wavelength transformational structure 100 is pre-production Wavelength converting member（The self-supporting being formed separately with Fig. 3 LED 60 and base 62（self-supporting）Ripple Long translation building block）, it includes the light absorbed by LED transmittings and launches one or more wavelength convert materials of the light of different wave length Material.One example of suitable Wavelength transformational structure 100 is self-supporting wavelength converting ceramic plate.Wavelength converting ceramic can be example Such as it is sintered into the powder phosphor of self-supporting slab.Except phosphor itself, the plate, which does not include typically, combines agent material.Suitably Plate can for example be at least 50 μ m-thicks in certain embodiments, in certain embodiments no more than 500 μ m-thicks, in some embodiments In at least 100 μ m-thicks, and be no more than 300 μ m-thicks in certain embodiments.Another example of suitable Wavelength transformational structure 100 It is to be placed in transparent material to form the powder material for transformation of wave length of self supporting structure.The example of suitable transparent material includes Silicones, glass and epoxy resin.

In Wavelength transformational structure 100（It is a variety of）Material for transformation of wave length can be conventional phosphor, organic phosphor, amount Sub- point, organic semiconductor, II-VI or III-V semiconductors, II-VI or III-V semiconductor-quantum-points or nanocrystal, dyestuff, gather Compound or luminous material.Any suitable powder phosphor can be used, including but not limited to based on garnet phosphor, Such as,（Its InAnd）、、、、And based on nitrogen Phosphor（Such asWith）.

Wavelength transformational structure 100 can include single material for transformation of wave length, material for transformation of wave length mixing or be formed as single Only layer rather than the multiple material for transformation of wave length mixed.The material for transformation of wave length that can will launch the light of different colours is pacified Put in the individual region of Wavelength transformational structure 100 or be blended together.

Light filter layer 102 can be deposited on the side of Wavelength transformational structure 100.In certain embodiments, filter Layer 102 is dichroic filter.Dichroic filter can be by such asEtc it is alternate （alternating）The thin layer of material and any other suitable material is formed.The thickness of filter layer 102 can be in some realities It is at least 10nm to apply in example, in certain embodiments no more than 5 μ m-thicks, at least 1 μ m-thick, and at some in certain embodiments It is no more than 2 μ m-thicks in embodiment.Total number of plies can be at least 2 layers in certain embodiments in light filter layer 102, in some realities Apply no more than 50 layers, in certain embodiments at least 10 layers in example, and be no more than 30 layers in certain embodiments.Each layer can To be identical thickness or the layer of different-thickness can be used.Can by being sputtered including megatron, DC sputtering, etc. from Dichroic filter layer 102 is deposited on wavelength and turned by any appropriate technology of son vapour deposition, chemical vapor deposition and evaporation Change in structure 100.

In certain embodiments, as illustrated in figure 10, disposed between Wavelength transformational structure 100 and filter 102 Smooth layer 103.The surface of Wavelength transformational structure 100 can play a role in terms of the validity of filter 102.In some implementations In example, if filter 102 is smoother, its performance is improved；Correspondingly, can be before filter 102 be deposited in ripple Smooth layer 103 is formed in long transformational structure 100, the smooth layer 103 is designed to be formed thereon the smooth of placement filter 102 Surface.For example, wavelength converting ceramic plate can have the surface Root Mean Square between 10nm and 600 μm（RMS）Roughness.If RMS roughness is more than such as 300 μm in some embodiments, then can be before filter 102 is formed in Wavelength transformational structure 100 Top forms smooth layer 103.Smooth layer 103 can be for example, one or more Si oxides, one or more titanyls Compound, one or more silicon nitrides, one or more transition metal oxides, or one or more transitional metal nitrides Thing.Smooth layer 103 can for example be at least 5nm thickness in certain embodiments, in certain embodiments no more than 500 μ m-thicks, At least 1 μ m-thick in some embodiments, and it is no more than 20 μ m-thicks in certain embodiments.

Change in the thickness of dichroic filter layer 102 may undesirably increase the " color extracted from device Cloud "（The distribution of the color point extracted from device）Size and/or interference for being launched by material for transformation of wave length and LED The color target of combination spectrum.

Correspondingly, in Figure 5, it has been created above clearly in light filter layer 102（clear）Non-wavelength translation and protection layer 104.The protective layer 104 can include such as silicone compounds KJR9222A/B and KRJ9226D, and other materials.One In a little embodiments, protective layer 104 have with the identical refractive index of light filter layer 102, to avoid the side between layer 102 and 104 Loss at boundary.Can use includes such as silk-screen printing, lamination, post forming（overmolding）, casting etc. it is various Any one in technology to form protective layer 104 above light filter layer 102.

In order to promote formation of the protective layer 104 above light filter layer 102, light filter layer 102 can be subjected to usual 2 minutes With 30 minutes between such as oxygen plasma, UV ozone etc. processing.In order to maximize the validity of the processing, the processing The delay between formation with protective layer 104（If any）A few houres should not be exceeded.

The thickness of protective layer 104 will be depended on for microballon explosion（micro-bead blasting）Effect reduces thick The expected degree of control of other processes of degree, and can be from 2 to 100 μm.Assuming that conventional treatment technology, then 20-40 μ M protective layer thickness typically will be enough.If silicones is used as into protection materials, the timetable solidified can be 80 DEG C 1 hour, then 120 DEG C 1 hour, and be then followed by 150 DEG C 4 hours.

Another example of suitable protective layer 104 is optical clear solid film, is such as formed at the top of light filter layer 102 Individual layerOr.The advantages of solid protective layer 104, is utilizing and above-described dichroic The identical instrument of filter 102 and the number that processing step can be reduced in the case of depositing solid protective layer simultaneously.Solid-state is protected Sheath 104 can be no more than 5 μ m-thicks in certain embodiments, and it is thick to be no more than 500nm in certain embodiments.

In figure 6, for example, by sawing or any other suitable technology in area 106 to including Wavelength transformational structure 100th, light filter layer 102, smooth layer 103（If there is）And the structure of protective layer 104 carries out scribing（diced）.

In the figure 7, LED 60 will be attached to by the structure of scribing, the LED 60 is attached to base 62.Illustrate One joint sheet 110 in the left side of base 62.Each Wavelength transformational structure 100 can be connected to by LED by adhesive 108 60.Any suitable adhesive can be used.One example of suitable adhesive is disposed between the tops of LED 60, in wavelength On the surface relative with light filter layer 102 of transformational structure 100 or silicones on both surfaces.For example, in some realities Apply in example, adhesive 108 is dropwise distributed above each LED 60（It is distributed as a series of drop）.

In certain embodiments, material for transformation of wave length can be placed in adhesive phase 108.For example, can be by powder Phosphor is mixed with layer of silicone adhesive 108, is then placed in the tops of LED 60.

In certain embodiments, to the selection of the material for transformation of wave length in any Wavelength transformational structure in device（Such as ripple Long transformational structure 100 and adhesive phase 108, the amount of used material for transformation of wave length, filter material and thickness）It is selected to Matching by the light launched of LED 60 peak wavelength so that the non-switched pump light from LED 60 of combination and leave this The light wavelength conversion of structure meets predetermined specification, such as is exported for color point and lumen.

The non-conversion light launched by LED 60 is often from a part for the final spectrum of the light of the structure extraction, although simultaneously Need not be such.The example of common combination includes the blue transmitting LED being combined with yellow launch wavelength transition material and green transmitting Blue transmitting LED, the UV being combined with blue transmitting and yellow launch wavelength transition material being combined with red launch wavelength transition material Launch LED, and launch LED with the UV that the material for transformation of wave length of blue transmitting, green transmitting and red transmitting is combined.Hair can be added The material for transformation of wave length of the light of other colors is penetrated with customized（tailor）From the spectrum of the light of structure transmitting.

In certain embodiments, LED 60 transmitting with blue peak wavelength light, Wavelength transformational structure 100 include absorb by The light and green and/or gold-tinted the one or more material for transformation of wave length of transmitting that LED 60 launches, and such as absorb and come from LED 60 blue light or light wavelength conversion and the material for transformation of wave length of the phosphor of transmitting feux rouges etc from Wavelength transformational structure 100 It is positioned in adhesive phase 108.In certain embodiments, light of the transmittings of LED 60 with blue peak wavelength, and wavelength turns Change the one or more that structure 100 includes absorbing by the light launched of LED 60 and launching some or all of green, yellow and feux rouges Material for transformation of wave length so that the material for transformation of wave length not added is positioned in adhesive phase 108.

In fig. 8, reflecting material 74 is formed above LED 60 and base 62.Reflecting material 74 fills adjacent LED 60 Between area 70.Reflecting material 74 can be the transparent or reflective support matrix for being for example such as placed in such as silicones etc （matrix）In TiO₂Or the reflection grain of alumina particle etc.Can be by including for example by reflection grain and branch support group In the mixture press-in area 70 of body or mould（molding）Any suitable technology form layer of reflective material 74.Such as Fig. 8 In it is illustrated, in the area 76 for the over top that reflecting material 74 can be placed in the protective layer 104 above each device. In some embodiments, by the skill for such as promoting molding of thinner area 112 of formation reflecting material etc above joint sheet 110 Art forms reflecting material 74, as illustrated in fig. 8.

In fig.9, make reflecting material 74 thinning to expose the top 78 of the protective layer 104 of the tops of LED 60 and exposed region Joint sheet 110 in 114.When reflecting material 74 is removed, the ambient light filter layer 102 of protective layer 104 is against damages.It can lead to Cross including any suitable of such as etching or such as mechanical technique of microballon explosion, wet pearl explosion, dry pearl explosion and grinding etc Technology remove excessive reflecting material 74.For example, in dry pearl explosion, 80 μm of sodium bicarbonate particle hits instead in the gas flow Penetrate the surface of material 74.In another example, in wet pearl explosion, 180 μm of plastic grain in water slurry is guided to reflection At the surface of material 74.Due to different etching mechanism, when protective layer 104 is silicones dry pearl explosion be suitable, And when protective layer 104 is silicones or such asEtc solid-state material when wet pearl explosion be suitable 's.

Protective layer 104 is protected and preserves the thickness of light filter layer 102, potentially avoids undesirably increasing color The thickness change of point cloud.Protective layer 104 should be sufficiently thick to adapt to be used to remove the removal of the technology of excessive reflecting material 74 Change without allowing the break-through of light filter layer 102 to damage.Reflecting material 74 can less be resistant to and remove compared with protective layer 104 Journey.The surface roughening of protective layer 104 can be promoted for removing the technology of excessive reflecting material 74, the surface roughening can be with Improve light extraction.

In certain embodiments, after excessive reflecting material 74 is eliminated, the top surface 78 of protective layer 104 is sudden and violent Dew, as illustrated in Fig. 9.The reflecting material 74 between LED 60 in area 70 prevents light from LED 60 side and wavelength The side escape of transformational structure 100 so that pass through the big of LED 60 top, Wavelength transformational structure 100 and light filter layer 102 Part light is extracted.In certain embodiments, reflecting material 74 and LED 60 side, Wavelength transformational structure, filter 102 with And a part for protective layer 104 directly contacts, as illustrated in Fig. 9.In certain embodiments, the top surface of reflecting material 74 Flushed with the top surface 78 of protective layer 104（Planarization）.

In certain embodiments, the top surface 78 of diaphragm 68 is roughened, textures or patterned is carried with improving light Take.Can be by removing the same process of excessive reflecting material 74 or in one or more individually processing steps on surface It is upper to form roughening, veining or patterning.

Although the present invention is described in detail, skilled artisans will appreciate that, the disclosure is given, can be with The modification of the present invention is made in the case of the spirit without departing from inventive concepts described herein.Therefore, it is not intended that this is sent out Bright scope is restricted to illustrated and description specific embodiment.

Claims (15)

1. a kind of method for making luminescent device, including：

The multiple LED for being attached to base are provided；

Filter is attached at least one in the multiple LED；

Protective layer is formed above the filter；

Reflecting layer is formed above the base to cover the protective layer and to fill the gap between LED；And

The part in the reflecting layer being placed in above the protective layer is removed to allow light to leave protective layer, and thus prevents light Escaped from LED side.

2. the method as described in claim 1, in addition to：Filter is formed on Wavelength transformational structure, wherein filter is attached It is connected at least one including the Wavelength transformational structure is adhered into the LED in the multiple LED.

3. method as claimed in claim 2, wherein the Wavelength transformational structure is wavelength converting ceramic.

4. method as claimed in claim 2, wherein the filter is dichroic filter.

5. method as claimed in claim 2, wherein the Wavelength transformational structure is adhered into the LED is included in the wavelength Silicones bonding layer is disposed between transformational structure and the LED.

6. method as claimed in claim 5, in addition to：Material for transformation of wave length is placed in the silicones bonding layer.

7. method as claimed in claim 2, wherein filter is formed on Wavelength transformational structure is included in Wavelength transformational structure Chip on form filter, methods described, which is additionally included in, adheres to the Wavelength transformational structure before the LED to described The chip of Wavelength transformational structure carries out scribing.

8. method as claimed in claim 2, in addition to：Before filter is formed, pacify above the Wavelength transformational structure Material is put to form smooth surface.

9. a kind of luminescent device, including：

It is attached to multiple LED of base；

The filter being placed in above the LED；

The hyaline layer being placed in above the filter；And

The reflecting material being filled between adjacent LED, but the reflecting material does not cover the hyaline layer, to allow light to leave Bright layer simultaneously prevents light from being escaped from LED side.

10. luminescent device as claimed in claim 9, in addition to：The ripple being placed between the filter and the multiple LED Long transformational structure.

11. luminescent device as claimed in claim 10, wherein, the Wavelength transformational structure is wavelength converting ceramic.

12. luminescent device as claimed in claim 10, in addition to：It is placed in the Wavelength transformational structure and the multiple LED Between bonding layer.

13. luminescent device as claimed in claim 12, in addition to：The material for transformation of wave length being placed in the bonding layer.

14. luminescent device as claimed in claim 9, wherein, the filter is dichroic filter.

15. luminescent device as claimed in claim 10, in addition to：Be placed in the filter and the Wavelength transformational structure it Between smooth layer.