JP2012039013A - Manufacturing method of light-emitting devices - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of LED light-emitting devices capable of easily mass-producing LED light-emitting devices having uniform light-emitting characteristics (chromaticity).SOLUTION: A manufacturing method of light-emitting devices comprises: a step B of selecting LEDs 1 with uniform characteristics; a step C of aligning the LEDs 1 on an adhesive tape 40 at predetermined intervals; a step D of applying a ceramic ink 30 in which phosphors are decentralized to the aligned LEDs 1 for temporary curing; a step E of adjusting light-emitting conditions of an LED light-emitting device 10 by grinding the ceramic ink 30 on the LEDs 1; a step F of cutting and separating the LEDs 1 with the ceramic ink 30 existing on top faces and side faces of the LEDs 1; and a step G of mainly curing the ceramic ink 30 by heating each of the separated light-emitting elements.

Description

  The present invention relates to a method for manufacturing a light-emitting device including a light-emitting element such as an LED element, and more particularly to a method for manufacturing a light-emitting device that localizes phosphors only around the light-emitting elements and eliminates waste of the phosphors. .

  In recent years, since an LED element (hereinafter abbreviated as LED) is a semiconductor element, it has a long life and excellent driving characteristics, is small in size, has high luminous efficiency, and has a bright emission color. Widely used for backlights and lighting. In the present invention, an LED light emitting device will be described as an embodiment.

  In particular, in recent years, LED devices have been proposed in which phosphors are localized only around the LED to save phosphors and eliminate color unevenness that depends on the viewing angle. Electrophoresis, spraying, and printing methods are well known as methods for localizing the phosphor around the LED in this LED device. The phosphor layer is formed in a wafer state, and the LED is separated from the wafer. There is also a manufacturing method to make it. (For example, cited reference 1)

  A conventional LED light emitting device with a sealing member will be described below. FIG. 4 is a plan view of a conventional LED wafer disclosed in FIG. 1 and paragraphs 0090 to 0098 in Patent Document 1, and FIG. 5 is a cross-sectional view. In the LED wafer 120, a plurality of semiconductor layers 100 are formed on a large sapphire substrate 110, and a P electrode 102 and an N electrode 103 are provided respectively. The main light emitting surface of the semiconductor layer 100 is the sapphire substrate 110 side, and only three LEDs 100 are shown in the drawing. However, a larger number of semiconductor layers 100 are formed on the actual large format sapphire substrate 110 to constitute the LED wafer 120.

  FIG. 6 is a process diagram for manufacturing a conventional LED light-emitting device in Patent Document 1, which is simplified without departing from the spirit of the process. In FIG. 6, step A is a step of preparing an LED wafer. Since the LED wafer 120 is inverted with respect to FIG. 5, the semiconductor layer 100 is formed and disposed below the large-sized sapphire substrate 110. Process B is a groove machining process in which a groove 111 is formed between the semiconductor layers 100 on the upper surface of the sapphire substrate 110 using a cutting tool. The groove 111 increases the light emitting area of the LED 200 including the semiconductor layer 100, and the light emitting area of the LED 200 is increased by the side surface formed by the groove 111.

  In Step C and Step D, a phosphor paste (phosphor layer 130 before solidification) is poured onto the upper surface of the sapphire substrate 110 including the groove 111, and the phosphor paste is flattened by the squeegee 140 and then solidified by heating to cause fluorescence. This is a phosphor layer forming step for forming the body layer 130. As the phosphor paste, in the case of a blue LED, an epoxy resin or silicon resin containing a phosphor can be used.

  Step E is a grinding step in which the upper surface of the phosphor layer 130 formed on the upper surface of the sapphire substrate 110 is uniformly ground using a grinding tool so as to have a target thickness. After this grinding step, the chromaticity is measured and accurately adjusted to the desired chromaticity. In addition, when the target chromaticity is not obtained in this state, the adjustment to the optimum chromaticity is finally performed by redoing the phosphor layer forming process in the process C and the process D and the grinding process in the process E. I do.

  Next, in step F, the LED wafer 120 is set on the processing table with the phosphor layer 130 facing upward, and the boundary of the semiconductor layer 100 (the center of the groove 111) is cut and separated using a cutting jig (blade) 150. Then, the individualized LEDs 200 shown in the process G are mass-produced.

  Further, in FIG. 4 and paragraphs 0112 to 0120 of the cited document 1, as another embodiment, a manufacturing method of the LED light emitting device similar to that of FIG. 6 is disclosed. The difference from FIG. 6 is that the LED included in the large sapphire substrate is an ultraviolet LED, and that the phosphor layer formed on the LED is formed using a glass-based binder that does not deteriorate due to the emission of the ultraviolet LED. is there. Then, the phosphor layer (paste-like) is formed and heat-cured in the same manner as in Steps C and D of FIG. 6, and then grinding in Step E and cutting and separation in Step F are performed.

  As described above, in the proposal of Patent Document 1, a plurality of LEDs are formed on a single large sapphire substrate, a phosphor layer is provided on the plurality of LEDs, and chromaticity adjustment is performed while grinding the phosphor layer. Is doing. When the desired chromaticity cannot be obtained, the phosphor layer formed after the characteristic measurement is peeled off and re-formed.

JP 2004-221536 A

  Recently, the thickness of the sapphire substrate 110 has become around 100 μm as the LED light-emitting element becomes thinner. However, since the total reflection components on the upper surface and the lower surface in the sapphire substrate 110 are not reduced, the amount of light emitted from the side surface of the sapphire substrate 110 is large. However, since the LED 200 has a portion without the phosphor layer 130 on the side surface of the sapphire substrate 110, the luminous efficiency is lowered. In particular, as the sapphire substrate 110 becomes thinner, the influence of this loss increases. As a countermeasure, if the exposed portion of the sapphire substrate 110 is thinned, the sapphire substrate 110 is easily broken during the manufacturing process.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems, and in an LED light emitting device manufacturing method that performs batch production using a highly reliable ceramic ink as a phosphor layer, an expensive phosphor material is used. The manufacturing method which can manufacture the LED light emitting element with good luminous efficiency easily can be provided.

In order to achieve the above object, the production method of the present invention comprises:
In a method for manufacturing a semiconductor light emitting device, a semiconductor light emitting device is flip-chip mounted on a circuit board, and a phosphor is provided around the semiconductor light emitting device.
Aligning the light emitting elements on the adhesive sheet at a predetermined interval;
Applying and curing a ceramic ink in which the phosphor is dispersed in the light emitting element; and
Cutting and separating the ceramic ink between the light emitting elements so that the thickness of the ceramic ink applied to the upper surface of the light emitting element is substantially equal to the thickness of the ceramic ink left on the side surface;
And a step of flip-chip mounting the light emitting element on a circuit board.

  In the step of aligning the light emitting elements on the adhesive sheet at a predetermined interval, it is preferable to select light emitting elements having uniform characteristics in advance and align the light emitting elements on the adhesive sheet at the predetermined interval.

  In the step of applying and curing the ceramic ink, the method preferably includes a step of temporarily curing the ceramic ink after the step of temporarily curing the ceramic ink and cutting and separating the ceramic ink between the light emitting elements.

  After the step of applying and curing the ceramic ink, it is preferable to provide a step of adjusting the light emission conditions of the light emitting element by grinding the ceramic ink on the light emitting element.

  Before the step of aligning the light emitting elements on the adhesive sheet at a predetermined interval, a step of forming bump electrodes on the light emitting elements in a wafer state, a step of cutting and separating into individual light emitting elements, and the characteristics of the light emitting elements And a measuring step.

  A step of forming a bump electrode on the light emitting element may be provided between the step of applying and curing the ceramic ink and the step of cutting and separating the ceramic ink between the light emitting elements.

  As described above, according to the manufacturing method of the present invention, the ceramic ink containing the phosphor is collectively applied to the light emitting elements arranged on the adhesive sheet, and after the ceramic ink is cured, the upper surface of the LED light emitting element and The ceramic ink is cut so that the side ceramic ink layers have substantially the same thickness. As a result, the LED light-emitting device that covers the side of the light-emitting element with the ceramic ink containing the phosphor and suppresses the decrease in the light emission efficiency while localizing the expensive phosphor material around the LED light-emitting element and saving the usage amount, It can be produced by a simple method based on coating and cutting.

It is process drawing which shows the manufacturing method of the LED light-emitting device in 1st Embodiment of this invention. It is process drawing which shows the manufacturing method of the LED light-emitting device in 2nd Embodiment of this invention. It is sectional drawing which shows the state which comprised the lens in the LED light-emitting device shown in FIG. It is a top view of the conventional LED wafer. It is AA sectional drawing of the LED wafer shown in FIG. It is process drawing which shows the manufacturing method of the conventional LED light-emitting device.

(First embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process diagram showing a method for manufacturing an LED light emitting device according to a first embodiment of the present invention. In FIG. 1, step A is a step of forming bumps on a wafer LED (light emitting element). P electrode bumps 2a and N electrode bumps 3a are formed on the P electrode 2 and N electrode 3 in each LED region included in the LED wafer 20 bonded to the adhesive sheet 40 by plating. Step B shows a step of cutting and separating individual LEDs and a step of measuring the characteristics of each LED. First, each LED area of the LED wafer 20 is cut and separated by scribing to form a plurality of LEDs 1. Next, in a state where the adhesive sheet 40 is stretched and the operability is improved, a probe for inspection is brought into contact with the P electrode bump 2a and the N electrode bump 3a of each LED 1, and the light emission characteristics of each LED 1 are measured. Sort. If necessary, the back surface (sapphire substrate) side of the LED wafer 20 may be ground before scribing.

  Step C is a step of aligning the LEDs on the adhesive sheet at a predetermined interval. The LEDs 1 of the same rank ranked in the process B are aligned and arranged on the support plate 50 (adhesive sheet) at a predetermined interval. Step D is a step of applying and curing the ceramic ink. In step C, the ceramic ink 30 in which the phosphor is dispersed and mixed is applied between the upper surfaces of the plurality of LEDs 1 and the elements (LEDs 1) arranged and arranged on the support plate 50 at predetermined intervals. Further, the applied ceramic ink is heated at about 90 ° C. to perform temporary curing of the ceramic ink. The ceramic ink is obtained by kneading particles such as a phosphor together with a catalyst and a solvent in a binder that becomes glassy when crosslinked. In this embodiment, organopolysiloxane is used as the binder. This ceramic ink is temporarily cured at about 90 ° C. (30 minutes), and is finally cured at about 160 ° C. (2 hours 30 minutes).

  Step E is a step of grinding the ceramic ink on the light emitting element to adjust the light emission conditions of the light emitting element. A portion 30a of the ceramic ink 30 temporarily cured in the process D is ground, and the thickness of the ceramic ink 30 is adjusted in accordance with characteristics (such as peak wavelengths) of the plurality of LEDs 1 arranged on the support plate 50 at predetermined intervals. The light emission characteristic (chromaticity) of the LED 1 provided with the ceramic ink layer 30 is adjusted to a desired value. In this case, since the characteristics of the plurality of LEDs 1 arranged in advance on the support plate 50 are within a certain rank (peak wavelength, etc.), the ceramic ink layer 30 covering the plurality of LEDs 1 arranged at predetermined intervals. By aligning the thickness of the LED with a constant thickness, the light emission characteristics (chromaticity) of all the LEDs 1 provided with the ceramic ink layer 30 can be accepted products that fall within a certain rank (chromaticity). Become. In this case, the calculation is performed in advance according to the light emission characteristics (such as peak wavelength) of the plurality of LEDs 1 arranged in alignment (for example, the relationship between the target chromaticity and the ceramic ink thickness with respect to the peak wavelength is confirmed in an experiment). The ceramic ink 30 may be ground to a thickness, or the light emission characteristics of the LED 1 may be measured while being ground to keep it within the standard.

  Step F is a step of cutting and separating the ceramic ink between the LEDs. A cutting jig (blade) 150 is provided so that the thickness of the ceramic ink 30 covering the upper surface of the LED 1 and the thickness of the ceramic ink 30 on the side surface remain substantially the same between the plurality of LEDs 1 arranged in alignment at a predetermined interval. Is used to cut the ceramic ink 30 and separate the LED 1. At this time, the support plate 50 is not cut. Step G is a step of fully curing the ceramic ink. The ceramic ink 30 is vitrified by performing a heat treatment at a high temperature (about 160 ° C.). This completes the LED 10.

  Step H is a step of flip-chip mounting the light emitting element on the circuit board. The completed LED 1 is flip-chip mounted on the sub-board 60 (circuit board) to complete the LED light emitting device 10. Actually, the LEDs 1 are not mounted on the individual sub-boards 60, but the plurality of LEDs 1 are flip-chip mounted on a collective board (not shown) from which a plurality of sub-boards 60 can be obtained by cutting and separating. In many cases, individual LED light emitting devices 10 are obtained by cutting and separating the LED. In order to prevent phosphor hydrolysis and electrode corrosion, it is preferable to seal the LED 1 with a transparent resin (not shown) in a collective substrate state.

  As described above, according to this embodiment, the LEDs 1 having the same emission characteristics (peak wavelength, etc.) are aligned on the support plate 50 in advance. Even without grinding in step E, the thickness of the ceramic ink layer 30 on the LED 1 is the same for each LED device 10, so that the light emission characteristics (chromaticity) of the LED devices 10 are also equal. When chromaticity management is not strict, it is not necessary to select light emitting elements having uniform characteristics in advance and align the light emitting elements on the adhesive sheet at a predetermined interval.

  In the present embodiment, the thickness for grinding the phosphor-containing ceramic ink 30 in step E can be determined for each lot (support plate 50). For this reason, since the LED light-emitting device 10 having desired light emission characteristics (chromaticity) can be obtained even if the support plates are different, it is suitable for mass production. This process can also be omitted when chromaticity management is not strict.

  In the present embodiment, the ceramic ink 30 is ground and cut in a semi-cured soft state, and after the step of cutting and separating the ceramic ink between the LEDs 1, the step of fully curing the ceramic ink (step F) is provided. For this reason, processing is easy, and production cost can be reduced and yield can be improved. Even if the ceramic ink 30 is fully cured in the process D, the process F can be omitted if a manufacturing apparatus capable of grinding and cutting the ceramic ink 30 can be prepared.

  In the present embodiment, before the step of aligning the light emitting elements on the adhesive sheet at a predetermined interval (step C), a step of forming bump electrodes on the light emitting elements in the wafer state (step A), and an individual light emitting element A process of cutting and separating (process B) and a process of measuring characteristics of the light emitting element (process B) were provided. Processes A and B are suitable when the package maker receives supply from the LED element maker on the LED wafer. If the characteristics (such as peak wavelength) are known and individual LEDs 1 with P and N electrode bumps 2a and 3a are available, steps A and B can be omitted.

Usually, the LED 1 for flip chip mounting includes a reflective layer on the P and N electrode bumps 2a, 3a side, so that the light emitted from the LED 1 to the sub-board 60 side is small. For this reason, even if there is no phosphor layer here, the light emission loss does not increase.
(Second Embodiment)

  Next, the manufacturing method of the LED light-emitting device in 2nd Embodiment of this invention is demonstrated using FIG. FIG. 2 is a process diagram showing a method for manufacturing an LED light-emitting device according to a second embodiment of the present invention, and is a process diagram showing a method for manufacturing an LED light-emitting device according to the first embodiment. The same numbers are assigned and duplicate descriptions are omitted.

  Step A is a step of aligning the LED elements on the adhesive sheet at a predetermined interval. The LEDs 1 of the same rank, which are ranked in advance, are arranged and arranged on the adhesive sheet 40 at a predetermined interval. At this time, the electrode forming surface of the LED 1, that is, the P electrode and N electrode (not shown) side is attached to the adhesive sheet 40 with the surface facing downward. Step B is a step of applying and curing the ceramic ink. In step A, the ceramic ink 30 in which phosphors are dispersed and mixed between the upper surfaces of the plurality of LEDs 1 arranged and arranged at predetermined intervals on the adhesive sheet 40 is applied. Further, the applied ceramic ink 30 is heated at about 90 ° C., whereby the ceramic ink 30 is temporarily cured.

  Step C is a step of adjusting the light emission conditions of the LED 1 by grinding the ceramic ink on the LED 1. A portion 30a of the ceramic ink 30 temporarily cured in the process B is ground, and the thickness of the ceramic ink 30 is adjusted according to the characteristics (peak wavelength, etc.) of the plurality of LEDs 1 arranged on the adhesive sheet 40 at a predetermined interval. The light emission characteristic (chromaticity) of the LED 1 is adjusted to a desired value. In this case, since the characteristics of the plurality of LEDs 1 arranged in advance on the support plate 50 are within a certain rank, the thickness of the ceramic ink 30 covering the plurality of LEDs 1 arranged at predetermined intervals is constant. By aligning the thickness, it becomes possible to make the light emission characteristics (chromaticity) of all the LEDs 1 acceptable products within a certain rank.

  Process D is a process of attaching to a new support plate (adhesive sheet). A support plate 50 (adhesive sheet) is affixed to the upper surface of the ceramic ink 30 ground in step C, and the adhesive sheet 40 on the upper surface is peeled by reversing from this state. Step E is a step of forming a plated electrode. A plated electrode film 5 that covers the entire surface is formed on the electrode surface of the LED 1 exposed by peeling off the adhesive sheet 40. Step F is a step of forming a resist film. A resist film 6 having openings in the bump formation region, that is, the P electrode and N electrode portions of each LED 1 is formed. The resist film 6 is formed by applying the resist film 6 applied on the entire surface to the P electrode 2 and the opening 6P corresponding to the P electrode 2 and the N electrode 3 by photolithography.

  Step G is a step of forming bump electrodes. By using the plated electrode film 5 formed in the step E as a common electrode, bump electrodes are grown on the openings 6P and 6N of the resist film 6 by electrolytic plating, whereby P electrode bumps 2a and N are formed on the openings 6P and 6N, respectively. Electrode bumps 3a are formed. Step H is a step of removing the resist film 6. The resist film 6 is removed using a processing solution. Further, the exposed plating electrode 5 is also removed using the P and N electrode bumps 2a and 3a as a mask.

  In Step I, between the LEDs 1, the thickness of the ceramic ink applied to the upper surface of the LED 1 and the thickness of the ceramic ink left on the side surface are substantially equal so as not to cut the support plate 50 (newly re-adhered adhesive sheet). This is a step of cutting and separating the ceramic ink. Similar to the step of cutting and separating the ceramic ink in step F shown in FIG. 1, the ceramic ink 30 mixed with the phosphor remaining on the side surface of the LED 1 has a predetermined thickness between the plurality of LEDs 1 arranged at predetermined intervals. Then, the ceramic ink 30 is cut and separated using a cutting jig (blade) 150 so that the LED 1 is mass-produced. Step I includes a step of fully curing the ceramic ink after cutting. Here, the ceramic ink 30 is vitrified by performing a heat treatment at a high temperature (about 160 ° C.). This completes LED1. Process J is a process in which the LED 1 is flip-chip mounted on the sub-board 10 (circuit board). The completed LED 1 is flip-chip mounted on the sub-board 60 to complete the LED light emitting device 10.

  In the manufacturing method according to the second embodiment, a bump electrode is formed on the LED (steps D to H) between the step B of applying and curing the ceramic ink and the step I of cutting and separating the ceramic ink between the LEDs. ). This is a manufacturing method suitable for a case where a package maker receives supply of an LED having no bumps from an LED element maker.

The manufacturing method of the present invention uses a ceramic ink that can withstand high heat as a phosphor binder, thereby ensuring heat resistance against high temperatures applied to the LED and circuit board during flip-chip mounting. If the LED is not provided with a reflective layer, the use of a highly reflective aluminum layer for the plated electrode 5 increases the reflection efficiency of the P and N electrode bumps and improves the light emission efficiency of the LED device 10.
(Third embodiment)

Next, an LED light-emitting device according to a third embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view of an LED light emitting device in which a lens 80 is provided on the LED light emitting device 10 produced by the manufacturing method shown in FIG. That is, the LED light-emitting device 10 created in the process H of FIG. 1 is formed with a hemispherical lens 80 by molding a transparent resin, and the light-emitting shape (light flux distribution) of the LED light-emitting device 10 is improved. As described in the first embodiment, when the lens 80 is simultaneously formed while the LEDs 1 are sealed with the collective substrate, the manufacturing efficiency is improved.

1,200 LED
2, 102 P electrode 2a P electrode bump 3, 103 N electrode 3a N electrode bump 5 Plating electrode film 6 Resist film 6P, 6N Opening 10, 200 LED light emitting device 20, 120 LED wafer 30, 30a Ceramic ink 40 Adhesive sheet 50 support plate 60 sub-substrate 80 lens 100 semiconductor layer 110 sapphire substrate 111 groove 130 phosphor paste 140 squeegee
150 cutting jig

Claims (6)

In a method for manufacturing a semiconductor light emitting device, a semiconductor light emitting device is flip-chip mounted on a circuit board, and a phosphor is provided around the semiconductor light emitting device.
Aligning the light emitting elements on the adhesive sheet at a predetermined interval;
Applying and curing a ceramic ink in which the phosphor is dispersed in the light emitting element; and
Cutting and separating the ceramic ink between the light emitting elements so that the thickness of the ceramic ink applied to the upper surface of the light emitting element is substantially equal to the thickness of the ceramic ink left on the side surface;
And a step of flip-chip mounting the light-emitting element on a circuit board.   In the step of aligning the light emitting elements on the adhesive sheet at a predetermined interval, light emitting elements having uniform characteristics are selected in advance, and the light emitting elements are aligned on the adhesive sheet at the predetermined interval. The manufacturing method of the light-emitting device of Claim 1.   The step of pre-curing the ceramic ink in the step of applying and curing the ceramic ink, and the step of fully curing the ceramic ink after the step of cutting and separating the ceramic ink between the light emitting elements. The manufacturing method of the light-emitting device as described in any one of 1 or 2.   4. The method according to claim 1, further comprising a step of adjusting a light emission condition of the light emitting element by grinding the ceramic ink on the light emitting element after the step of applying and curing the ceramic ink. 5. The manufacturing method of the light-emitting device of description.   Before the step of aligning the light emitting elements on the adhesive sheet at a predetermined interval, a step of forming bump electrodes on the light emitting elements in a wafer state, a step of cutting and separating into individual light emitting elements, and the characteristics of the light emitting elements The method for manufacturing a light emitting device according to claim 1, further comprising a step of measuring. 5. A bump electrode is formed on the light emitting element between the step of applying and curing the ceramic ink and the step of cutting and separating the ceramic ink between the light emitting elements. The manufacturing method of the light-emitting device as described in any one of these.

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