TW201349602A - Method of manufacturing LED device and LED wafer - Google Patents

Abstract

A method of manufacturing LED device and an LED wafer are provided. The method includes the following steps: forming an epitaxial structure having a plurality of LED mesas on an epitaxial substrate; replacing the epitaxial substrate with a cooling substrate; measuring the wavelengths of the light from the LED mesas and generating a wavelength data accordingly; disposing a grid board on the epitaxial structure, which grid board has a plurality of injection holes to expose the LED mesas respectively; and coating phosphor glue on the LED mesas through the injection holes to form lighting devices on the cooling substrate.

Description

Method for manufacturing light-emitting diode element and light-emitting diode wafer

The present invention relates to a method of fabricating a light-emitting diode, and more particularly to a method of fabricating a light-emitting diode element and a light-emitting diode wafer formed using the method.

Light Emitting Diode (LED) is a solid-state light-emitting element composed of P-type and N-type semiconductor materials, which can generate self-radiating light in the ultraviolet, visible and infrared regions. LEDs have many advantages such as power saving, long life and high brightness. Recently, LEDs have become more and more widely used in environmental protection, energy saving and carbon saving. For example, traffic signs, street lamps, flashlights, LCD backlight modules or For example, various types of lighting devices such as LED bulbs.

In the conventional LED manufacturing process, the wavelength of the LED is different due to the position of the LED on the wafer due to the process variation of the epitaxial process. In general, the wavelength distribution of the light-emitting diodes will exhibit a circumferential distribution, taking a 2-inch substrate as an example, and the wavelength from the center of the wafer is about ±5 nm. Performing a wafer level package under such wavelength distribution conditions causes the mixed white light lumens and color dots to fall within different bins, that is, in different wavelength ranges. The LED components thus produced need to be further classified to converge the wavelengths in the same gear.

Depending on the application, the customer will require that the wavelength and electrical properties of the LED components be within certain tolerances, so the manufacturer must first test and classify the LEDs before shipping. Light-emitting diodes can be classified according to wavelength, illuminating angle, luminous intensity, and operating voltage. Due to the increasing demand for LED wavelength distribution in commercial applications, such as LED display screens or display-related applications, the wavelength distribution Requirements even in the range of 0.5nm . Therefore, for LED manufacturers, this will increase testing, classification and manufacturing costs.

Embodiments of the present invention provide a method of fabricating a light emitting diode device and a light emitting diode wafer having uniform light emitting wavelength characteristics. Before the package, the component electrical test is performed first, and then according to the test result, the phosphor paste of different phosphor powder ratios is applied to the respective light-emitting diode components, so that the wavelength distribution of the entire light-emitting diode wafer can be Convergence and within the required error range, such as within the same bin. Thereby, the effect of uniform illumination of the entire wafer is achieved, and after packaging, it can be applied to the same product without classification.

Embodiments of the present invention provide a method for fabricating a light emitting diode device, comprising the steps of: forming an epitaxial structure on an epitaxial growth substrate having a plurality of mesa light emitting diodes; a heat dissipating substrate is substituted for the epitaxial growth substrate; measuring an emission wavelength of each of the high-profile LEDs to generate a wavelength measurement data; and an adhesive plate is disposed on the epitaxial structure to prevent overflow, the annotation The rubber sheet has a plurality of glue injection holes respectively exposing the high-profile light-emitting diodes; and coating the fluorescent glue on the light-emitting diodes via the injection holes to form a plurality of the heat-dissipating substrates Light-emitting elements.

In the embodiment of the present invention, the step of applying the fluorescent glue to each of the high-profile light-emitting diodes through the injection holes to form a plurality of light-emitting elements further comprises: adjusting the firefly according to the wavelength measurement data. The phosphor concentration or composition ratio in the photo-adhesive is such that the emission wavelengths of the respective light-emitting elements are in a specific range.

In the embodiment of the present invention, the method further includes: after coating the phosphor paste on each of the high-profile LEDs, forming a separate light-emitting component by using the cutting process to form the light-emitting elements on the heat-dissipating substrate. .

In the embodiment of the present invention, the epitaxial growth is replaced by the heat dissipation substrate The step of: bonding the epitaxial structure to a temporary substrate; removing the epitaxial growth substrate; attaching the epitaxial structure to one of the temporary substrates to a heat dissipation substrate, and the heat of the heat dissipation substrate The conductivity is greater than the heat conductivity of the epitaxial growth substrate; and the temporary substrate is removed.

Another embodiment of the present invention provides a light emitting diode wafer including a heat dissipation substrate and an epitaxial structure. The epitaxial structure is disposed on the heat dissipation substrate, and the epitaxial structure has a plurality of high-profile light-emitting diodes. Each of the high-profile light-emitting diodes is coated with a fluorescent glue to form a plurality of light-emitting elements on the heat-dissipating substrate, and the light-emitting wavelengths of the light-emitting elements are in a specific range.

In summary, in the embodiment of the present invention, before the wafer is cut, the fluorescent glue is coated on the individual light-emitting diodes, and the pre-coated phosphor powder is adjusted according to the light-emitting wavelength of the light-emitting diode (ie, LED mesa). In proportion, the illumination wavelength of the entire LED can be located in a specific range, such as in the same file. Thereby, the process of the light-emitting diode and the cost of the classification of the light-emitting diodes are simplified.

The above described features and advantages of the present invention will be more apparent from the following description.

In the following, the invention will be described in detail by the embodiments of the invention, and the same reference numerals are used in the drawings.

Embodiments of the present invention provide a method for fabricating a light-emitting diode element, which uses a jig to separate a compartment on a light-emitting diode wafer, and then applies different ratios according to the electrical properties (eg, wavelength) of the individual light-emitting diode elements. The phosphor is used to homogenize the wavelength of the light-emitting diode elements on the entire wafer. Thereby, the problem of uneven distribution of light emission wavelength caused by process variation is improved, and the light emitting diode wafer is made After the package is diced, a light-emitting diode element having a uniform optical wavelength can be obtained. In addition, since the entire light-emitting diode wafer has a similar light-emitting wavelength, it can also be used as a single light source.

Please refer to FIG. 1 and FIG. 2A to FIG. 2I. FIG. 1 is a flow chart of a method for manufacturing a light-emitting diode element according to an embodiment of the present invention, and FIGS. 2A to 2I are light-emitting diodes according to an embodiment of the invention. Schematic diagram of the process of the component. First, referring to step S110 and FIG. 2A, an epitaxial structure 220 is formed on the epitaxial growth substrate 210 by using a light emitting diode epitaxial process, and the epitaxial structure 220 has a plurality of mesa light-emitting diodes 221, 222. The material of the epitaxial growth substrate 210 is, for example, sapphire, GaP, GaAs, AlGaAs, or tantalum carbide (SiC). The epitaxial growth substrate 210 of the present embodiment is exemplified by a sapphire substrate, and the lattice direction is, for example, (0001). However, the present invention does not limit the substrate material and lattice direction used.

The epitaxial structure 220 can be formed by metal organic chemical vapor deposition (MOCVD), liquid phase epitaxy (LPE) or molecular beam epitaxy (MBE). Formed, the embodiment is not limited. The epitaxial structure 220 may define a P-type semiconductor layer, an N-type semiconductor layer, an active layer, and a metal electrode of the light-emitting diode element through a process such as lithography, etching, ion implantation, deposition, or the like to form a mesa light-emitting device. Polar body. Each of the high-profile LEDs represents a light-emitting diode element.

Then, referring to step S120 and FIG. 2B to FIG. 2E, the epitaxial growth substrate 210 is replaced by the heat dissipation substrate 212. Alternatively, the epitaxial structure 220 is first adhered to a temporary substrate 230, as shown in FIG. 2B. After the front surface of the epitaxial growth substrate 210 is fixed to the temporary substrate 230, the epitaxial growth substrate 210 is removed, as shown in FIG. 2C. Show. Then, the back surface of the epitaxial structure 220 (ie, not attached to one side of the temporary substrate 230) is attached to the heat dissipation substrate 212 as shown in FIG. 2D. Next, the temporary substrate 230 is removed as shown in FIG. 2E. The epitaxial structure 220 and the heat dissipation substrate 212 may be bonded together by the thermal conductive adhesive 213. However, the embodiment does not limit the material of the thermal conductive adhesive 213 and the bonding manner between the epitaxial structure 220 and the heat dissipation substrate 212.

The temporary substrate 230 is, for example, a ceramic substrate, a metal substrate, or a plastic substrate, and the embodiment is not limited. The heat dissipation substrate 212 is, for example, a metal substrate or a germanium substrate, and the embodiment is not limited. It should be noted, however, that the heat conductivity of the heat sink substrate 212 must be greater than the heat conductivity of the epitaxial growth substrate 210. That is to say, the heat dissipation effect of the heat dissipation substrate 212 is better than that of the epitaxial growth substrate 210.

In the present embodiment, the fixing between the temporary substrate 230 and the epitaxial growth substrate 210 can be performed by heating the temporary substrate 230 and the epitaxial growth substrate 210 by using a solid wax. The method of removing the epitaxial growth substrate 210 can be realized by using an LED grinder, and the steps are as follows: firstly, the front surface of the epitaxial growth substrate 210 is adhered to a metal disc or a ceramic disc of a fixed wafer, and then ground to remove the epitaxial crystal. The excess thickness of the substrate 210 is grown. Next, the heat dissipation substrate 212 is adhered to the bottom surface of the polished epitaxial growth substrate 210 (ie, the bottom surface of the epitaxial structure 220) to replace the original epitaxial growth substrate 210. The metal disk or ceramic disk used to fix the wafer on the LED grinder can be regarded as the temporary substrate 230 in this embodiment. Of course, in this embodiment, the epitaxial structure 220 can also be attached to the temporary substrate 230 by using other bonding methods, which is not limited in this embodiment.

It should be noted that the thickness of the epitaxial growth substrate 210 may be removed according to requirements, and part of the thickness may be retained to enhance the structural strength of the epitaxial structure 220 to avoid chipping. Therefore, in step S120, although the epitaxial growth substrate 210 is replaced by the heat dissipation substrate 212, in practice, the partial thickness of the epitaxial crystal remains. The long substrate 210 can be allowed. That is to say, the heat dissipation substrate 212 can be used to replace the thickness of the majority of the epitaxial growth substrate 210 or completely replace the thickness of the epitaxial growth substrate 210 to achieve heat dissipation and reinforcement structure.

The epitaxial structure 220 and the heat dissipation substrate 212 may be adhered by using a heat dissipating adhesive or a silver adhesive, as long as the effects of fixing and heat conduction can be achieved, and the embodiment is not limited thereto.

Referring to steps S130 and 2F, after the epitaxial growth substrate 210 is replaced by the heat dissipation substrate 212, the emission wavelengths of the high-profile LEDs 221 and 222 are measured to generate a wavelength measurement data. The electrical measurement method can be measured by using a light-emitting diode measuring device or a sorting device, and the wavelength measuring data includes light intensity, wavelength, reference voltage, color temperature and the like, and the most important one is the wavelength. In the classification of LEDs, it can be divided into multiple bin stages with reference to the above information such as wavelength and operating voltage. The light-emitting diodes in the same bin level have electrical properties similar to those of the light-emitting wavelength, for example, in the wavelength range of 5 nm or 1 nm. Distinguish each bin.

Next, referring to step S140 and FIG. 2G, the adhesive plate 240 is disposed on the epitaxial structure 220. The adhesive plate 240 has a plurality of injection holes 241 and 242 for exposing the high-profile LEDs 221 and 222, respectively. The hole walls 241a, 242a of the respective injection holes 241, 242 are respectively located around the corresponding high-profile LEDs 221, 222 to form a compartment, and the function thereof is mainly to avoid overflow during the injection.

Referring to step S150 and FIGS. 2H and 2I, the glue injection devices 251 and 252 apply the phosphor paste to the high-profile LEDs 221 and 222 via the injection holes 241 and 242 to form the light-emitting elements 261 and 262. After the adhesive board 240 is removed, the phosphor paste adheres to the high-profile LEDs 221 and 222, thereby adjusting the wavelengths of the light-emitting elements 261 and 262. In addition, the phosphor paste also has a protective effect, and a protective layer can be formed on the high-profile LEDs 221 and 222. The phosphor paste coated by the individual high-profile LEDs 221 and 222 will be based on individual high-profile LEDs. The wavelength measurement data of 221 and 222 adjust the phosphor powder concentration or the composition ratio thereof, so that the light emission wavelengths of the light-emitting elements 261 and 262 are in a specific range, for example, 1 nm or 5 nm, and the embodiment does not limit the specific range. Value.

It should be noted that the glue injection devices 251 and 252 can uniformly distribute the phosphor powder in each independent space by means of potting or dusting to apply the fluorescent substance on the high-profile LEDs 221 and 222. . This embodiment does not limit the coating method of the coated phosphor, nor does it limit the composition of the phosphor.

It should be noted that, in this embodiment, the wavelength of the light-emitting elements on the entire wafer may be in the same bin or the partial regions of the wafer may be in the same gear according to design requirements. With the manufacturing method of the present embodiment, the light-emitting wavelengths of all the light-emitting diode crystal grains can be adjusted before the wafer is cut, thereby simplifying the manufacturing process and the classification cost of the light-emitting diode. In addition, with the manufacturing method of the present embodiment, the adjusted wafer can be subjected to a wafer-level package, and the wavelength generated by each of the light-emitting diode elements can be located in the same file.

After the phosphor paste is applied to each of the high-profile LEDs 221 and 222, the light-emitting elements 261 and 262 on the heat-dissipating substrate 212 are separated into light-emitting elements 261 and 262 by a dicing process. The cutting is performed together with the heat dissipation substrate 212 to form the light-emitting elements 261, 262 having the heat-dissipating substrate at the bottom, and the cutting manner is, for example, laser cutting, but the embodiment is not limited thereto.

It should be noted that, in this embodiment, the cutting process of the wafer may be performed at any stage, for example, before or after the measurement process (step S130), or in the fluorescent glue (powder) coating process (step S150). Before or after, the embodiment is not limited. In other words, the process steps in this embodiment may have the following three procedures in accordance with the order: cutting→pointing→upper phosphor powder; spotting→cutting→upper phosphor powder; Spot test → upper phosphor powder → cutting; Since the wafer after cutting can still maintain its original shape for the process of measuring and coating the phosphor, the user can cut the wafer according to the process requirements, and then measure and fluoresce. The procedure of the powder; or the procedure of cutting and polishing the phosphor first; or the procedure of measuring and polishing the phosphor before performing the cutting process. That is to say, this embodiment does not limit the time during which the wafer cutting process occurs, as long as the process of wafer measurement and the upper phosphor is not affected.

In addition, referring to FIG. 2H and FIG. 2I, the electrodes (Pad) 271 and 272 on the high-profile LEDs 221 and 222 may be covered first to avoid the fluorescent glue (powder) before the application of the fluorescent glue (powder). ) coated on the electrodes 271, 272. Then, after the phosphor paste (powder) is applied, the cover is removed to expose the electrodes 271, 272. In this embodiment, a specific structure may be designed on the adhesive board 240 to cover the electrodes 271 and 272; or the electrodes 271 and 272 may be covered by a removable material such as photoresist, and then removed by a process. The remaining embodiments of the cover electrodes 271, 272 should be easily inferred by those skilled in the art after the disclosure of the present invention, and the present embodiment will not be repeated.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of the adhesive sheet 240 according to the embodiment. The glue plate 240 has a plurality of honeycomb-type compartments that can be used to space the respective high-profile LEDs 221, 222. Each compartment 310 has a glue injection hole 241 and a hole wall 241a surrounding the glue injection hole 241. When the adhesive plate 240 is overlaid on the wafer (ie, the epitaxial structure), a spacer may be formed on the epitaxial structure 220 to be spaced apart from the light emitting diode epitaxial structure (ie, the high-profile LED 221, 222). It should be noted that FIG. 3 is only a schematic view of the adhesive sheet 240 of the embodiment, and the embodiment is not limited thereto.

From another point of view, the manufacturing method using the above-described light emitting diode element The emission wavelength of the entire wafer can be adjusted in the same file. Please refer to FIG. 4. FIG. 4 is a schematic diagram of a light emitting diode wafer according to another embodiment of the present invention. The light emitting diode wafer 400 includes a heat dissipation substrate 410 and an epitaxial structure 420. The epitaxial structure 420 has a plurality of high-profile light-emitting diodes disposed on the heat dissipation substrate 410. The epitaxial structure 420 may be formed on a light-emitting diode substrate (such as a germanium substrate, a sapphire substrate, etc.), and then the heat-dissipating substrate 410 may be used instead of the original light-emitting diode substrate. The heat dissipation substrate 410 is, for example, a tantalum substrate or a metal substrate.

Each of the high-profile light-emitting diodes is coated with a fluorescent paste to form a plurality of light-emitting elements on the heat-dissipating substrate 410. By adjusting the composition of the phosphor powder (such as the ratio of YAG phosphor powder, red phosphor powder, yellow phosphor powder, and green phosphor powder), the light-emitting wavelength of the light-emitting element 421 on the light-emitting diode wafer 400 is located. Within a specific range. In general, fluorescent materials for LEDs mostly use phosphate, citrate and aluminate as the substrate, and then add transition metal or rare earth element as a sensitizer or activator in the crystal lattice, so that photoluminescence can be achieved. The effect is to change the color of the LED and improve the luminous efficiency. This embodiment does not limit the material of the phosphor powder or the formulation of the phosphor paste.

White LEDs can be composed of blue LEDs and yellow phosphors, or blue LEDs with green and red phosphors. The phosphor powder is mixed with a binder (such as epoxy resin) to form a fluorescent gel. In addition, the fluorescent glue may be added with a functional material such as a brightener or a curing agent, and the composition of the fluorescent gel is not limited in this embodiment. Adjusting the proportion of phosphor in the phosphor can change the wavelength of the excitation light, thereby achieving the effect of adjusting the wavelength of the LED. Those skilled in the art, after having disclosed the invention, should be able to easily infer an embodiment of changing the wavelength by adjusting the phosphor powder, which is not described in detail in this embodiment.

It should be noted that this embodiment can divide the entire diode wafer 400 into three regions 411, 412, 413 according to the electrical properties of the individual components. Area 411 412 and 413 respectively apply phosphor pastes having different phosphor powder ratios, thereby adjusting the light-emitting wavelength thereof so that the entire diode wafer 400 is located within a specific wavelength range. After adjustment, the light-emitting wavelength of the light-emitting element 421 on the entire diode wafer 400 can converge to a specific wavelength range for use by a particular product or a particular customer. Of course, in this embodiment, different phosphor pastes may be separately coated according to the electrical properties of the individual components, thereby adjusting the light-emitting wavelength thereof. In addition, the embodiment can also be divided into light-emitting regions having different wavelengths according to design requirements. For example, the regions 411, 412, and 413 are formed into three light-emitting regions of different wavelengths.

In summary, the present invention replaces the original growth substrate with a heat dissipation substrate, and adjusts the applied fluorescent glue according to the electrical properties of the individual light-emitting diode elements to enable the light-emitting diode component after coating the fluorescent glue ( That is, the light-emitting elements can have similar emission wavelengths. Thereby, the invention can make the illumination wavelength of the whole wafer in the same gear, thereby reducing the classification cost, and can make the light-emitting components produced by the whole wafer be applied to the same product without additional classification.

Although the embodiments of the present invention have been disclosed as above, the present invention is not limited to the above-described embodiments, and those skilled in the art can make some modifications without departing from the scope of the present invention. The scope of protection of the present invention is therefore defined by the scope of the appended claims.

210‧‧‧ epitaxial growth substrate

220‧‧‧ epitaxial structure

221, 222‧‧‧High-profile light-emitting diode

230‧‧‧ Temporary substrate

212‧‧‧heating substrate

213‧‧‧thermal adhesive

221, 222‧‧‧High-profile light-emitting diode

240‧‧‧Injection sheet

241, 242‧‧‧ injection hole

241a, 242a‧‧‧ hole wall

251, 252‧‧‧ glue injection device

261, 262‧‧‧Lighting elements

271, 272‧‧‧ electrodes

310‧‧‧ Compartment

400‧‧‧ Diode Wafer

410‧‧‧heating substrate

411, 412, 413‧‧‧ areas

420‧‧‧ epitaxial structure

421‧‧‧Lighting elements

S110~S150‧‧‧ Flowchart steps

1 is a flow chart of a method of fabricating a light emitting diode device in accordance with an embodiment of the present invention.

2A-2I are schematic diagrams showing processes of a light emitting diode device according to an embodiment of the invention.

FIG. 3 is a schematic view of the glue plate according to the embodiment.

4 is a schematic diagram of a light emitting diode wafer according to another embodiment of the present invention.

S110~S150‧‧‧ Flowchart steps

Claims (8)

A method for fabricating a light-emitting diode element, comprising: forming an epitaxial structure on an epitaxial growth substrate, the epitaxial structure having a plurality of high-profile light-emitting diodes; and replacing the epitaxial growth substrate with a heat-dissipating substrate; Measure the illuminating wavelength of each of the high-profile LEDs to generate a wavelength measurement data; and set an adhesive plate on the epitaxial structure, the squeegee has a plurality of injection holes to expose the respective a high-profile light-emitting diode; and coating the phosphor paste on the light-emitting diodes via the injection holes to form a plurality of light-emitting elements on the heat-dissipating substrate. The method for manufacturing a light-emitting diode element according to claim 1, wherein the step of applying a fluorescent glue to each of the high-profile light-emitting diodes via the injection holes to form a plurality of light-emitting elements The method further includes: adjusting the phosphor powder concentration or the composition ratio in the phosphor paste according to the wavelength measurement data, so that the light emission wavelengths of the light-emitting elements are in a specific range. The method for manufacturing a light-emitting diode device according to claim 1, further comprising: after applying the fluorescent glue to each of the high-profile light-emitting diodes, the heat-dissipating substrate is formed by a cutting process The light-emitting elements form separate light-emitting elements. The method for manufacturing a light-emitting diode device according to claim 1, wherein the step of replacing the epitaxial growth substrate with the heat dissipation substrate comprises: attaching the epitaxial structure to a temporary substrate; removing the Lei a crystal growth substrate; the epitaxial structure is not attached to one surface of the temporary substrate and attached to a heat dissipation substrate, and the thermal conductivity of the heat dissipation substrate is greater than the thermal conductivity of the epitaxial growth substrate; And removing the temporary substrate. The method for producing a light-emitting diode element according to any one of claims 1 to 4, wherein the epitaxial growth substrate is a sapphire substrate, and the heat dissipation substrate is a germanium substrate or a metal substrate. The method for manufacturing a light-emitting diode element according to claim 5, wherein the hole walls of each of the injection holes are respectively located around the corresponding high-profile light-emitting diodes to prevent overflow. A light-emitting diode wafer includes: a heat-dissipating substrate; and an epitaxial structure disposed on the heat-dissipating substrate, the epi-crystal structure having a plurality of high-profile light-emitting diodes; wherein each of the high-profile light-emitting diodes The phosphors are respectively coated on the body to form a plurality of light-emitting elements on the heat-dissipating substrate, and the light-emitting wavelengths of the light-emitting elements are in a specific range. The light-emitting diode wafer according to claim 7, wherein the heat-dissipating substrate is a germanium substrate or a metal substrate.