KR20130110381A - Manufacturing method of semiconductor light emitting device having a wavelength conversion layer - Google Patents

Abstract

PURPOSE: A method of manufacturing a semiconductor light emitting device including a wavelength conversion layer improves the color distribution of the light emitting device manufactured from a substrate by leveling the rear surface of the substrate before the wavelength conversion layer is formed. CONSTITUTION: A wafer (11) in which a semiconductor laminate (15) is formed is provided. Multiple electrodes (16) are formed on the semiconductor laminate. The lower surface of the wafer is polished by using a polishing device (G1). A structure with a specific height is formed on the electrodes. A wavelength conversion layer composed of resin containing wavelength conversion materials is formed on the semiconductor laminate. The wavelength conversion layer is polished to expose the structure.

Description

Manufacturing method of semiconductor light emitting device having a wavelength conversion layer {Manufacturing Method of Semiconductor Light Emitting Device having a Wavelength Conversion Layer}

The present invention relates to a method for manufacturing a semiconductor light emitting device, and more particularly, to a method for manufacturing a semiconductor light emitting device having a wavelength conversion layer.

In general, a semiconductor light emitting diode (Semiconductor light emitting diode) is a device used to transmit a signal converted from the electrical energy into the infrared, visible light or light by using the characteristics of the compound semiconductor, the current group III-V compound semiconductor Light emitting diodes using are widely commercialized.

Each chip constituting the light emitting device may be formed by growing a semiconductor layer on one wafer and then separating the wafer into chips by a cutting process. A process of forming a wavelength conversion layer including a wavelength conversion material such as phosphor particles and quantum dots is formed on the upper surface of each separated light emitting device.

In this case, in order to perform the process of forming the wavelength conversion layer on the upper surface of the individual devices, a process of aligning each chip is performed separately.

In addition, in order to improve the color coordinate yield, it is necessary to keep the thickness of the wavelength conversion layer constant. However, the wafer is bent due to the difference in thermal expansion coefficient with the epitaxial, and thus, the wafer has a predetermined curvature on the surface to which the wavelength conversion layer is applied, thus making it difficult to form a wavelength conversion layer having a uniform thickness. . Such nonuniform thickness of the wavelength conversion layer can cause a large variation in the color difference index indicating the difference in color.

This deviation in color difference index may be caused by the epitaxial itself. In other words, even in the epitaxial growth process, the difference in the growth conditions depending on the wafer region may cause a difference in the composition or thickness of the active layer, so that the primary wavelength light of each light emitting device region may have a different spectrum according to the position of the wafer. . The color difference index problem may also occur due to the problem of epitaxial itself.

Accordingly, the art provides a new method of manufacturing a semiconductor light emitting device that can form a wavelength conversion layer with a uniform thickness so that the color difference index can be managed in a certain allowable range.

According to an aspect of the present invention, there is provided a method including preparing a wafer having a top surface on which semiconductor stacks for a plurality of light emitting devices are formed, wherein a plurality of electrodes for the plurality of light emitting devices are formed on the semiconductor stack. Grinding the lower surface of the wafer to planarize, forming a structure having a predetermined height on the plurality of electrodes, and using a resin containing a wavelength conversion material on the semiconductor laminate so that the structure is covered. Forming a wavelength conversion layer formed, and polishing the wavelength conversion layer to a desired thickness so that the structure is exposed; provides a light emitting device manufacturing method comprising a.

The forming of the wavelength conversion layer may include applying a liquid resin containing the wavelength conversion material on the semiconductor laminate, and curing the liquid resin containing the wavelength conversion material to form the wavelength conversion layer. It may include a step.

In this case, in the preferred embodiment of the present invention, the step of accelerating the precipitation of the wavelength conversion material in the liquid resin between the step of applying and the curing may further comprise.

Accelerating the precipitation of the wavelength conversion material may be a step of maintaining a liquid resin containing the wavelength conversion material at a temperature equal to or higher than the previous process temperature and lower than a curing start temperature.

Accelerating the precipitation of the wavelength conversion material may be a step of maintaining the liquid resin containing the wavelength conversion material at 80 to 100 ℃ for at least 5 minutes.

The structure is a photoresist material, and after the polishing, may further include removing the structure to expose the electrode. Alternatively, the structure may be a conductive bump.

In certain embodiments, prior to forming the wavelength conversion layer, the method may further include half dicing a wafer on which the semiconductor stack is formed so that at least the semiconductor stack is separated into individual light emitting devices.

The forming of the wavelength conversion layer may include forming the wavelength conversion layer so that a wavelength conversion material is filled in the half dicing region.

Cutting the wafer may include cutting the wafer such that the wavelength conversion layer is maintained in a side region of the light emitting device obtained by half dicing.

The wafer is a conductive wafer, and the plurality of electrodes may be formed such that one electrode is positioned in each light emitting device region.

According to another aspect of the present invention, there is provided a method including: providing a wafer having a top surface on which semiconductor laminates for a plurality of light emitting devices are formed, wherein a plurality of electrodes for the plurality of light emitting devices are formed on the semiconductor laminate; Forming a structure having a predetermined height on the substrate, applying a liquid resin containing the wavelength conversion material on the semiconductor laminate to cover the structure, and forming the structure of the wavelength conversion material in the liquid resin. Accelerating the precipitation, curing the liquid resin containing the wavelength conversion material to form the wavelength conversion layer, and polishing the wavelength conversion layer to a desired thickness so that the structure is exposed. Provided is a device manufacturing method.

Accelerating the precipitation of the wavelength conversion material may be a step of maintaining a liquid resin containing the wavelength conversion material at a temperature equal to or higher than the previous process temperature and lower than a curing start temperature.

Accelerating the precipitation of the wavelength conversion material may be a step of maintaining the liquid resin containing the wavelength conversion material at 80 to 100 ℃ for at least 5 minutes.

By forming the back surface of the substrate before forming the wavelength conversion layer, color scattering of the light emitting device manufactured from the substrate can be greatly reduced. In combination with or alone, a wavelength converting material-containing liquid resin is applied to form a wavelength converting layer, and before curing, the precipitation is accelerated to uniform the distribution of wavelength converting materials such as phosphors in the resin. It can be further improved.

1A to 1G are cross-sectional views illustrating processes for manufacturing a semiconductor light emitting device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an example of a light emitting device equipped with the semiconductor light emitting device shown in FIG. 1G.
3 is a cross-sectional view for each step for explaining a subsequent step of the semiconductor light emitting device manufacturing method according to the specific example of one embodiment of the present invention.
FIG. 4 is a cross-sectional view illustrating an example of a light emitting device having the semiconductor light emitting device manufactured in FIG. 3.
5A and 5B show chromatic dispersion of a semiconductor light emitting device manufactured according to the conventional example A1 (without the planarization process of the substrate back surface).
6A and 6B show chromatic dispersion of a semiconductor light emitting device manufactured according to the conventional example A2 (without the planarization process of the substrate back side).
7A and 7B show chromatic dispersion of a semiconductor light emitting device manufactured according to Example B1 of the present invention.
8A and 8B show color dispersion of a semiconductor light emitting device manufactured according to Example B2 of the present invention.
9A and 9B show color dispersion of a semiconductor light emitting device manufactured according to Example B3 of the present invention.
10A and 10B show color dispersion of a semiconductor light emitting device manufactured according to Example B4 of the present invention.
11 is a process flowchart for explaining a phosphor precipitation process that can be employed in the present invention.
12 is a graph showing a change in viscosity with temperature of a resin that can be employed in the present invention.
Fig. 13 is a color coordinate system showing color dispersion of a light emitting device manufactured according to the conventional example D1.
Fig. 14 is a color coordinate system showing color scatter of a light emitting device manufactured according to Example E2 of the present invention.
15A to 15H are cross-sectional views for each process for explaining a method for manufacturing a semiconductor light emitting device according to another embodiment (half dicing application example) of the present invention.
16 is a cross sectional view for each step for explaining a subsequent step in the method for manufacturing a semiconductor light emitting device according to a specific example of another embodiment of the present invention.
17 and 18 are a plan view and a side cross-sectional view showing an example of a semiconductor light emitting element that can be employed in the present invention.
Fig. 19 is a side sectional view showing another example of the semiconductor light emitting element employable in the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1D are cross-sectional views of processes for describing a method of manufacturing a semiconductor light emitting device according to an embodiment of the present invention.

As shown in FIG. 1A, a wafer 11 on which semiconductor stacks 15 for a plurality of light emitting devices are formed is provided.

The semiconductor laminate 15 may include a first conductive semiconductor layer 15a and a second conductive semiconductor layer 15b and an active layer 15c disposed therebetween. A plurality of electrodes 16 for the plurality of light emitting devices is formed on the semiconductor stack 15.

In the present embodiment, the wafer 11 may be a conductive wafer, and if necessary, the conductive wafer 10 may be used as an electrode on one side. Although one electrode 16 is illustrated in each of the individual light emitting device regions, the present invention is not limited thereto and may be implemented as an electrode structure having a plurality of electrodes or extension electrodes having various shapes.

For example, the semiconductor laminate adopted in this embodiment may be a semiconductor laminate for forming a semiconductor light emitting element having the structure shown in Figs.

In general, as shown in FIG. 1A, there may be a non-planar element I on the back side of the substrate 11 used as a wafer, and in particular, the semiconductor laminate 15 and the substrate 11 Since the material is composed of different materials, stress may be generated during the growth process or the cooling process after the growth due to the difference in the coefficient of thermal expansion, which may cause the wafer to bend in a certain direction. The backside of the substrate 11 may provide a non-flat surface due to this non-flat element 11 or bending.

This non-flat surface is a step of forming a wavelength conversion layer (Fig. 1D) or polishing the wavelength conversion layer on the semiconductor laminate 15 on the opposite side by using the back surface of the substrate as a base surface in a subsequent step (Fig. 1E). ), It becomes difficult to form a wavelength conversion layer having a uniform thickness. This distribution of thickness may result in a large difference in color scatter. In order to prevent this, the present inventor proposes a method of smoothly polishing the rear surface of the substrate 11 prior to the process of forming the wavelength conversion layer.

That is, as illustrated in FIG. 1B, a process of polishing the back surface of the substrate 11 to be flattened is performed.

The semiconductor laminate 15 is disposed on the support panel S, and in this state, the back surface of the substrate 11 may be polished to have a flat surface by using the polishing apparatus G1. Through the polishing process, the back surface of the substrate 11 is flattened, thereby ensuring a uniform thickness of the wavelength conversion layer formed in a subsequent process. The color scatter improvement effect according to this will be described in more detail with reference to the related embodiments.

Subsequently, as shown in FIG. 1C, structures 17 and 18 having a predetermined height h are formed on the plurality of electrodes 16.

The structures 17 and 18 employed in the present embodiment may be formed of a material capable of maintaining the structure without greatly deforming in the wavelength conversion layer forming and polishing process. The structures 17 and 18 employable in this embodiment can be classified into two types depending on whether they remain in the final product. That is, the structure may be divided into a sacrificial pattern 17 or a conductive bump 18 such as a conventional bonding metal that can be easily removed in a subsequent process (after the polishing process).

Preferably, the height of the structures 17 and 18 may be set in consideration of the desired thickness of the final wavelength converting layer. Specifically, the structures 17 and 18 are preferably formed at a height h sufficient so that the upper end thereof is higher than the top height of the final wavelength conversion layer 19 of FIG. 1D.

In addition, when the structure is to be removed as the sacrificial pattern 17, it is preferable to secure a sufficient bonding area to facilitate the wire connection to the electrode located on the bottom of the removed region.

As shown in FIG. 1D, the wavelength conversion layer 19 is formed on the semiconductor laminate 15 to cover the structures 17 and 18. That is, as described above, the wavelength conversion layer 19 may be formed to a sufficient thickness t1 to cover the structure 17.

The wavelength conversion layer 19 employed in the present embodiment may be a transparent resin layer containing the wavelength conversion material (P). However, the present invention is not limited thereto and may be a wavelength conversion layer of various known types. For example, the wavelength conversion layer 19 is a film composed of a wavelength conversion material itself, and may be a ceramic phosphor film manufactured by a sputtering process using a ceramic phosphor as a target. The wavelength conversion layer 19 may be formed to an appropriate thickness in consideration of this, because a predetermined thickness is removed in a subsequent polishing process.

The wavelength converting material P employed in the present embodiment may be a phosphor or a quantum dot or a combination thereof. The wavelength converting material is converted into yellow or yellowish orange together with yellow or red and green or red and green to obtain white light. It may be a substance.

The phosphor may be a YAG-based, TAG-based, silicate-based, sulfide-based, or nitride-based phosphor. As quantum dots, a nano crystal material exhibiting a quantum confinement effect, and includes Si-based nanocrystals, II-VI compound semiconductor nanocrystals, III-V compound semiconductor nanocrystals, and IV-VI compound semiconductors. It may be a nanocrystal.

The resin containing the wavelength conversion material may be at least one of epoxy, silicon, polystyrene, and acrylate.

If necessary, the wavelength conversion layer 19 may further include a light scattering powder such as Al ₂ O ₃ or TiO ₂ .

The wavelength conversion layer 19 employed in the present embodiment is not limited thereto, but the first and second layers 19a and 19b may be sequentially formed in separate processes. Screen printing, spin coating, dispensing, spray coating, tape attaching, electrophoresis, deposition process, sputtering and compression molding It can be formed using a known process.

In this example, the wavelength conversion layer 19 is illustrated as covering the structures 17 and 18, but is not limited thereto. That is, if the wavelength conversion layer 19 is provided with a sufficient thickness, it may also be considered that the structures 17 and 18 are formed in an exposed form. In the present wavelength converting layer forming process, the back surface of the previously planarized substrate is provided as a flat base to maintain a high flatness of the working surface, thereby helping to uniformly provide the wavelength converting layer.

As shown in FIG. 1E, the wavelength conversion layer 19 is polished to expose the structures 17 and 18.

The wavelength conversion layer 19 is polished to be reduced to a desired thickness using a predetermined polishing apparatus G2. The structures 17 and 18 may be exposed through the surface of the wavelength conversion layer 19 polished through the polishing process. The thickness t of the final wavelength conversion layer 19 can be defined by this process. In particular, in the polishing process for controlling the thickness, the work surface to be polished is processed to have a high flatness of the back surface of the substrate 11 provided as the base surface, and thus the flatness of the final wavelength conversion layer can be maintained at a high level. Can be guaranteed.

As described above, the subsequent process may then proceed in different ways depending on the type of structure employed in this embodiment. As a representative example of the structure, as described above, the process according to the sacrificial pattern 17 and the conductive bump 18 can be divided.

First, FIGS. 1F and 1G will be described as an example of employing the sacrificial pattern 17 as a structure.

As shown in FIG. 1F, the sacrificial pattern 17 is removed to expose the electrode 16.

In the region O from which the sacrificial pattern is removed, an electrode may be exposed to provide a bonding region. The sacrificial pattern removing process may be performed by decomposing the sacrificial pattern 17 by applying an appropriate solvent or by dissolving the interface. When the sacrificial pattern 17 is a photoresist pattern, the flux may penetrate along the surface of the sacrificial pattern to easily peel off the sacrificial pattern 17, which is a photoresist.

The sacrificial pattern removal process can be maintained almost intact without significantly damaging the polished wavelength conversion layer 19 by selectively reacting only with the material constituting the sacrificial pattern 17.

Subsequently, as illustrated in FIG. 1G, the wafer 11 on which the semiconductor laminate 15 is formed is cut so that the plurality of light emitting devices 10 are obtained.

The process of separating the wafer 11 on which the semiconductor stack 15 is formed in units of elements is not limited thereto, and may be performed using a known process such as dry etching and mechanical cutting.

In the above-described embodiment, since the surface of the deposited electrode is provided as it is without forming a separate conductive bump in the bonding region, as shown in FIG. 2, strong bonding strength can be ensured at the time of wire bonding. FIG. 2 is a cross-sectional view showing an example of a light emitting device equipped with the semiconductor light emitting device manufactured in FIG. 1G.

Referring to FIG. 2, a semiconductor light emitting device 10 is shown bonded using a conductive adhesive layer 27 on a circuit board 21 having first and second circuit patterns 26a and 26b. In the semiconductor light emitting device 10, the electrode 16 and the second circuit pattern 26b may be electrically connected through a wire (W).

In this embodiment, since the wire W is not connected to the electrode 16 through a conductive bump (not shown) containing a relatively large number of defects, the wire W is directly connected to the surface of the electrode 16, thereby providing a strong bonding strength. It provides an advantage that can be guaranteed.

The sacrificial pattern 17 employed in the foregoing embodiments may be a photoresist. The photoresist has an advantage of being able to stably maintain the exposed area of the electrode even during the wavelength conversion layer forming process, and to be easily and easily peeled off by an appropriate solvent. In addition, the photoresist also has the advantage that a precise pattern formation process is possible.

Unlike the previous example, the structure may be provided with conductive bumps 19, as shown in FIG.

As shown in Fig. 3, the resultant shown in Fig. 1E can be cut into individual individual unit units. In the individually cut semiconductor light emitting device 10 ', the conductive bumps 18 are not only exposed by the wavelength conversion layer being removed by the preceding polishing process, but also together with the second layer 19b of the wavelength conversion layer 19. It may be polished to have the same plane as the planarized surface of the second layer 19b.

In this structure, the exposed flat top surface of the conductive bump 18 may be provided as a bonding area for connecting with the circuit pattern 26b of the external circuit board, as shown in FIG.

As described above, according to the above-described embodiment, the step of flattening the back surface of the substrate 11 is preceded by the wavelength conversion layer forming step (especially, the thickness adjusting step). Even after execution, the wavelength conversion layer 15 can have a constant thickness regardless of the position of the individual chips on the wafer (substrate). As a result, variation in chromaticity due to variation in thickness of the wavelength conversion layer can be minimized.

Hereinafter, operations and effects of the introduction of the substrate back planarization process will be described with reference to specific embodiments.

< Conventional example A>

A nitride semiconductor light emitting device having 455 nm wavelength light was manufactured by growing a nitride single crystal on Si-Al wafers (two wafers) under MOCVD equipment.

The flatness of the wafer backside was measured. As a result, the flatness (deviation) of each of the wafers A1 and A2 was measured at 10.1 µm and 10.7 µm.

Subsequently, a photoresist structure is formed on each electrode without any additional process on the back surface of the wafer, and a phosphor-containing resin (phosphor: resin weight compounding ratio of a red phosphor and a green phosphor is mixed with a silicone resin using a spin coating process). 0.9: 1). Subsequently, the phosphor layer was polished to a thickness of about 70 μm and the photoresist structure was exposed, and then an appropriate flux was applied to remove the exposed photoresist.

For the final result, the color characteristics of all the chip units at each wafer level were measured, and the chromaticity of each virtual wafer area and the whiteness of each chip were displayed in the 1931 color coordinate system.

5A and 5B show color dispersion of a semiconductor light emitting device manufactured according to the conventional example A1, and Figs. 6A and 6B show color dispersion of the semiconductor light emitting device manufactured according to the conventional example A2.

< Example B>

The process was performed under the same conditions as in Conventional Example A, except that a planarization process for the back surface of the substrate was introduced.

A nitride semiconductor light emitting device having 455 nm wavelength light was manufactured by growing a nitride single crystal on Si-Al wafers (four wafers) using MOCVD equipment under the same conditions.

Subsequently, an additional polishing process was performed on the wafer back side to improve the flatness of the wafer back side. As a result of measuring the improved flatness of the back surface of the wafer, the flatness (deviation) of each of the wafers B1, B2, B3, and B4 was 6.1 µm, 4.7 µm, 5.7 µm and 5.7 µm, respectively.

Subsequently, a photoresist structure was formed on each electrode under the same conditions as in the conventional example A, and a phosphor-containing resin (a phosphor: resin weight ratio of 0.9 was obtained by mixing a red phosphor and a green phosphor with a silicone resin using a spin coating process). : 1) was applied. Subsequently, the phosphor layer was polished to a thickness of about 70 μm and the photoresist structure was exposed, and then an appropriate flux was applied to remove the exposed photoresist.

Similarly to the conventional example A, the color characteristics of all the chip units at each wafer level were measured for the final result of this example B, and the chromaticity for each virtual wafer region and the whiteness of each chip were displayed in the 1931 color coordinate system.

Referring to the color scattering obtained in FIGS. 7 to 10, relatively uniform chromaticity appears in the entire wafer area as compared to FIGS. 5 and 6. As a result, the color coordinates of each chip are distributed in a more dense area, thereby greatly improving color scattering. I could confirm that.

As described above, it can be seen that the planarization process of the rear surface of the substrate has a large influence on the color scattering prior to the planarization of the wavelength conversion layer, and the color scattering can be improved through the planarization process of the rear surface of the substrate. .

According to another aspect of the present invention, when the liquid resin is used in the process of forming the wavelength conversion layer to improve color scattering, the distribution of the wavelength conversion material in the resin layer may be uniformed by accelerating the precipitation rate of the wavelength conversion material. . Since the difference in the spatial distribution of the wavelength conversion material also causes a deviation in chromaticity, it provides a method of improving the uniformity of the distribution of the wavelength conversion material (sedimentation induction) through the precipitation acceleration process. Scattering improvement through this precipitation acceleration may be carried out alone or in combination with the preceding process.

11 is a process flowchart for explaining a new wavelength conversion layer forming process that can be employed in the present invention.

Referring to FIG. 11, the process of forming the wavelength conversion layer may be started by applying a liquid resin containing the wavelength conversion material on the semiconductor laminate (S101). The liquid resin can be suitably used as long as it is a curable resin having a silicone resin, an epoxy resin, or a mixture thereof as well as other known light transmissive properties. The present coating process may employ any of the processes described in FIG. 1D.

Then, in step S103, the precipitation of the wavelength conversion material in the liquid resin is accelerated. Of course, the process may be carried out before the liquid resin is cured, preferably before the curing start temperature.

In particular, since there may be a temperature section that can maintain a viscosity higher than room temperature in a certain temperature range before curing, prior to the present curing process, it is possible to obtain a desired precipitation acceleration process by maintaining a certain time in this temperature section. In particular, after the coating step of the wavelength conversion layer, it is possible to sufficiently accelerate the precipitation of the wavelength conversion material by maintaining a predetermined time at a temperature condition that can maintain a viscosity equal to or higher than the coating step temperature.

Referring to FIG. 12, it can be seen that a temperature section having a high viscosity exists before the curing start temperature of the curable liquid resin. Fig. 14 shows the viscosity change with the temperature of the other mixed resin (b) together with the silicone resin (a). In the case of the silicone resin, it has a relatively low viscosity at 80 to 100 ° C, and in the case of a specific mixed resin, it can be confirmed that the resin has a relatively low viscosity at 60 to 120 ° C.

Thus, by maintaining a constant time in this temperature section before curing, for example, 5 minutes or more, 10 minutes or more, the precipitation is accelerated and the wavelength conversion material according to the process variation (especially the waiting time between application and curing). The difference in chromaticity due to the nonuniform distribution of can be reduced.

Subsequently, the liquid resin containing the wavelength conversion material is cured to form the wavelength conversion layer (S105). Since the wavelength conversion material in the wavelength conversion layer obtained by curing is subjected to the precipitation accelerating process, the wavelength conversion material may be in the most precipitated state, and as a result, a uniform distribution of the wavelength conversion material may be obtained.

Hereinafter, operations and effects of the introduction of the substrate back planarization process will be described with reference to specific embodiments.

< Example  C>

A nitride semiconductor light emitting device having 455 nm wavelength light was manufactured by growing a nitride single crystal on Si-Al wafers (2: C1, C2) using MOCVD equipment.

Subsequently, an additional polishing process was performed on the wafer back surface to improve the flatness of the wafer back surface (flatness: 5.7 μm).

Subsequently, a photoresist structure was formed on each electrode under the same conditions as in the conventional example A, and a phosphor-containing resin (a phosphor: resin weight ratio of 0.9 was obtained by mixing a red phosphor and a green phosphor with a silicone resin using a spin coating process). : 1) was applied.

Subsequently, after curing for 5 minutes at a temperature (eg, 50 ° C.) applied during the coating process for 5 minutes before curing, the mixture was cured at 150 ° C. for 60 minutes in a heating oven.

Next, the phosphor layer was polished to a specific thickness (C1: 77 mu m, C2: 68 mu m) and the photoresist structure was exposed, and then an appropriate flux was applied to remove the exposed photoresist.

< Example  D>

The same conditions as in Example C were carried out except that a precipitation accelerating step was introduced in the wavelength conversion layer (phosphor layer) formation step.

A nitride semiconductor light emitting device having 455 nm wavelength light was manufactured by growing a nitride single crystal on Si-Al wafers (three wafers) under MOCVD equipment.

Subsequently, a photoresist structure was formed on each electrode under the same conditions as in the conventional example A, and a phosphor-containing resin (a phosphor: resin weight ratio of 0.9 was obtained by mixing a red phosphor and a green phosphor with a silicone resin using a spin coating process). : 1) was applied.

Subsequently, after curing for 10 minutes at 80 ° C. using an IR oven prior to curing to accelerate the precipitation of the phosphor, the mixture was cured at 150 ° C. for 60 minutes in a heating oven.

Next, the phosphor layer was polished to a specific thickness (D1: 66 μm, D2: 70 μm, D3: 68 μm) and the photoresist structure was exposed, and then an appropriate flux was applied to remove the exposed photoresist.

< Example E>

The same conditions as in Example D were carried out except that the wavelength conversion layer formation process conditions (precipitation acceleration conditions, etc.) were slightly different.

A nitride semiconductor light emitting device having 455 nm wavelength light was manufactured by growing a nitride single crystal on Si-Al wafers (two wafers) under MOCVD equipment.

Subsequently, a photoresist structure was formed on each electrode under the same conditions as in the conventional example A, and a phosphor-containing resin (a phosphor: resin weight ratio of 0.9 was obtained by mixing a red phosphor and a green phosphor with a silicone resin using a spin coating process). : 1) was applied.

Subsequently, 200 minutes at 80 ° C. was used for 200 minutes using an IR oven before curing to accelerate the precipitation of the phosphor, followed by curing at 150 ° C. for 60 minutes in a heating oven.

Next, the phosphor layer was polished to a specific thickness (E1: 70 μm, E2: 72 μm) and the photoresist structure was exposed, and then an appropriate flux was applied to remove the exposed photoresist.

Along with Example C, the color characteristics of all the chips obtained at each wafer level for the final products of Examples D and E were measured and the distribution characteristics of the color coordinates were confirmed. As a result, it was confirmed that the color scattering can be greatly improved by additionally introducing a process for accelerating the precipitation of the wavelength conversion material as in Examples D and E as compared with Example C.

13 and 14 are color coordinate systems showing the color scatter of Examples C1 and E2, and the distribution tendency of the color coordinates to influence the precipitation is that Example E2 shows a slight red shift, but the color scatter is much improved. Can be.

Therefore, if the type or content of the phosphor is appropriately adjusted, even if the precipitation acceleration process is used, the effect of improving color scattering can be expected to satisfy 80% or more of the desired target color coordinate region.

As such, when the liquid resin is used in the process of forming the wavelength conversion layer in order to improve color scattering, the distribution of the wavelength conversion material in the resin layer may be uniformed by accelerating the precipitation rate of the wavelength conversion material. Since the difference in the spatial distribution of the wavelength conversion material also causes chromaticity deviation, it can be improved by uniformizing the distribution (sedimentation induction) of the wavelength conversion material through the precipitation acceleration process. Scattering improvement through this precipitation acceleration may be carried out alone or in combination with the preceding process.

15A to 15H are cross-sectional views illustrating processes for manufacturing a semiconductor light emitting device according to one embodiment of the present invention.

As shown in FIG. 15A, the semiconductor laminate 35 may include a first conductive semiconductor layer 35a and a second conductive semiconductor layer 35b and an active layer 35c disposed therebetween. A plurality of electrodes 36 for the plurality of light emitting devices are formed on the semiconductor stack 35.

Since the semiconductor laminate 35 and the substrate 31 are made of different materials, stress is generated during the growth process or the cooling process after the growth due to the difference in the coefficient of thermal expansion. As shown in FIG. Non-planar elements on the back of the substrate may be generated in a predetermined direction or during or after the process.

Next, as shown in Fig. 15B, a step of polishing the back surface of the substrate 31 to be flattened is performed.

The semiconductor laminate 35 is disposed on the support panel S, and in this state, the back surface of the substrate 11 may be polished to have a flat surface by using the polishing apparatus G1. Through the polishing process, the back surface of the substrate 31 is flattened, thereby ensuring a uniform thickness of the wavelength conversion layer formed in a subsequent process.

As shown in Fig. 15C, the wafer 31 on which the semiconductor stack 35 is formed is half dicing so that at least the semiconductor stack 35 is separated into individual light emitting device units.

Through this process, the side surface of the semiconductor laminate 35 may be exposed through the half diced region HD. As in the present embodiment, a portion of the wafer 31 may be diced to completely expose the side surface of the semiconductor laminate 35.

As shown in FIG. 15D, a structure 37 having a predetermined height h is formed on the plurality of electrodes 36.

The structures 37 and 38 employed in the present embodiment may be formed of a material capable of maintaining the structure without greatly deforming in the wavelength conversion layer forming and polishing process. The structures 37 and 38 employable in the present embodiment have a sacrificial pattern 37 that can be easily removed in a subsequent process (after polishing), depending on whether it remains in the final product, and a conductive bump made of a conventional bonding metal. (38).

Preferably, the heights of the structures 37 and 38 may be set in consideration of the desired thickness of the final wavelength converting layer. Specifically, the structures 37 and 38 may be formed at a sufficient height h so that the height of the upper end thereof is higher than the top height of the final wavelength conversion layer 39.

As shown in FIG. 15E, the wavelength conversion layer 39 is formed on the semiconductor laminate 35 so that the structures 37 and 38 are covered.

As described above, the wavelength conversion layer 39 may be formed to a sufficient thickness t1 to cover the structures 37 and 38.

The wavelength conversion layer 39 employed in the present embodiment may be a light transmissive resin layer containing the wavelength conversion material (P). However, the present invention is not limited thereto and may be a wavelength conversion layer of various known types. The contents described in FIG. 1D may be combined with reference to describe specific contents of the process.

In particular, in the present process, the wavelength conversion layer 39 may be formed to cover the structures 37 and 38 while the wavelength conversion material is filled in the half diced region HD.

As shown in Fig. 15F, the wavelength conversion layer 39 is polished so that the structures 37 and 38 are exposed.

The wavelength conversion layer 39 is polished to be reduced to a desired thickness by using a predetermined polishing device G2. The structures 37 and 38 may be exposed through the surface of the wavelength conversion layer 39 polished through the polishing process. The thickness t2 of the final wavelength conversion layer 39 may be defined by the present process. In particular, in the polishing process for adjusting the thickness, the work surface to be polished may be maintained by being processed to have a high flatness of the back surface of the substrate 31 provided as the base surface, and the final wavelength conversion layer 39 may be thick (t2). ) Uniformity can be ensured at a high level.

As described above, the structure employed in the present embodiment can be largely divided into the sacrificial pattern 37 and the conductive bumps 38, depending on whether handled in a subsequent process.

The embodiment shown in Figs. 15G and 15H illustrates a subsequent process of the type employed as the sacrificial pattern.

First, as shown in FIG. 15G, the sacrificial pattern 37 is removed to expose the electrode 36.

In the region O from which the sacrificial pattern is removed, an electrode may be exposed to provide a bonding region. The sacrificial pattern removing process may be performed by decomposing the sacrificial pattern 37 by applying an appropriate solvent or by dissolving the interface.

Subsequently, as shown in Fig. 15H, the wafer 31 on which the semiconductor laminate 35 is formed is cut so that the plurality of light emitting elements 30 are obtained.

In the present cutting process, the wavelength conversion layer 38 may be maintained in the side region of the light emitting device 30 obtained by the half dicing. In addition, by appropriately adjusting the cutting width in the device separation process, the thickness of the wavelength conversion layer 39 located on the side surface can be controlled to a desired thickness range.

In the present embodiment, the wavelength conversion layer 39 can be additionally applied to the side surfaces of the semiconductor laminate 35 except for the wafer 31 to substantially secure the wavelength conversion region. As described above, in the manufacturing process using half dicing, the wafer may be a conductive wafer, and may be advantageously employed in a form in which one electrode is positioned in each light emitting device region.

Further, in the present embodiment, the half dicing process is illustrated as being performed after the wafer 31 is prepared and before the sacrificial pattern 37 is formed, but is satisfied that the half dicing process is performed before the wavelength conversion layer 39 is formed. . That is, it may be executed after the sacrificial pattern 37 is formed as necessary.

Unlike the previous example, the structure may be provided with conductive bumps 39, as shown in FIG.

As shown in Fig. 16, the resultant shown in Fig. 15F can be cut into each individual element unit. In the individually cut semiconductor light emitting device 30 ', the conductive bumps 38 are not only exposed by the wavelength conversion layer being removed by the previous polishing process, but also have a substantially same plane by polishing the wavelength conversion layer 39. Can be. In this structure, the exposed flat top surface of the conductive bump 38 may be provided as a bonding region.

17 and 18 are a plan view and a side cross-sectional view showing an example of a semiconductor light emitting element that can be employed in the present invention.

As shown in FIGS. 17 and 18, the semiconductor light emitting device 200 may include a conductive substrate 210, a first electrode layer 220, an insulating layer 230, a second electrode layer 240, and a second conductive semiconductor. The layer 250b, the active layer 250c, and the first conductivity type semiconductor layer 250a are included.

The first electrode layer 220 is not only stacked on the conductive substrate 210, but as shown, a portion of the first electrode layer 220 is formed in the insulating layer 230, the second electrode layer 240, and the second conductive layer. The first conductive semiconductor layer 250a extends through the contact hole 280 penetrating the semiconductor semiconductor layer 250b and the active layer 250c and penetrating a predetermined region of the first conductive semiconductor layer 250a. In contact with the conductive substrate 210 and the first conductivity-type semiconductor layer 250a is provided to be electrically connected.

That is, the first electrode layer 220 electrically connects the conductive substrate 210 and the first conductive semiconductor layer 270, and electrically connects the contact hole 280 to the contact hole 280. ), More precisely, is electrically connected through the contact hole 280 through the contact area 290 where the first electrode layer 220 and the first conductive semiconductor layer 250a contact each other.

On the other hand, the insulating layer 220 to electrically insulate the first electrode layer 220 from other layers except for the conductive substrate 210 and the first conductivity type semiconductor layer 250a on the first electrode layer 220. Is provided. That is, the insulating layer 220 is not only between the first electrode layer 220 and the second electrode layer 240 but also the second electrode layer 240 and the second conductivity type semiconductor exposed by the contact hole 280. It is also provided between the side surfaces of the layer 250b and the active layer 250c and the first electrode layer 220. In addition, the insulating layer 220 may also be insulated from the side surface of the first conductive semiconductor layer 250a through which the contact hole 280 passes.

The second electrode layer 240 is provided on the insulating layer 220. Of course, as described above, the second electrode layer 240 does not exist in predetermined regions through which the contact hole 280 passes. In this case, as shown in the drawing, the second electrode layer 240 includes at least one or more exposed regions, ie, exposed regions 245, in which a part of an interface contacting the second conductive semiconductor layer 250b is exposed. An electrode pad part 247 may be provided on the exposed area 245 to connect an external power source to the second electrode layer 240.

In addition, the semiconductor laminate 250 is not formed on the exposed region 245. In addition, the exposed region 245 is preferably formed at the edge of the semiconductor light emitting device 200 as shown, in order to maximize the light emitting area of the semiconductor light emitting device 200. Meanwhile, the second electrode layer 240 preferably includes one of Ag, Al, and Pt metal, which is electrically connected to the second conductive semiconductor layer 250b. As a layer having a property of minimizing contact resistance of the second conductivity-type semiconductor layer 250b and reflecting the light generated by the active layer 250c to the outside to increase the luminous efficiency. It is because it is preferable to be provided.

The second conductivity type semiconductor layer 250b is provided on the second electrode layer 240, and the active layer 250c is provided on the second conductivity type semiconductor layer 250b, and the first conductivity type semiconductor is provided. The layer 250a is provided on the active layer 250b. In this case, the first conductivity-type semiconductor layer 250a may be an n-type nitride semiconductor, and the second conductivity-type semiconductor layer 250b may be a p-type nitride semiconductor.

Alternatively, in another light emitting device 300 employable in the present invention, the first electrode layer connected to the contact hole may be exposed to the outside.

Referring to FIG. 19, in the light emitting device 300, a second conductive semiconductor layer 350b, an active layer 350c, and a first conductive semiconductor layer 350a are formed on the conductive substrate 310. In this case, the second electrode layer 340 may be disposed between the second conductive semiconductor layer 350b and the conductive substrate 310, and unlike the previous embodiment, the second electrode layer 340 is not necessarily required.

In the present embodiment, the contact hole 380 having the contact region 390 in contact with the first conductivity-type semiconductor layer 350a is connected to the first electrode layer 320, and the first electrode layer 320 is moved to the outside. It is exposed and has an electrical connection 345. The electrode pad part 347 may be formed in the electrical connection part 345. The first electrode layer 320 may be electrically separated from the active layer 350c, the second conductive semiconductor layer 350b, the second electrode layer 340, and the conductive substrate 310 by the insulating layer 330.

In the above embodiment, unlike the contact hole was connected to the conductive substrate, in the present embodiment, the contact hole 380 is electrically separated from the conductive substrate 310 and the first electrode layer 320 connected to the contact hole 380. ) Is exposed to the outside. Accordingly, the conductive substrate 310 is electrically connected to the second conductivity type semiconductor layer 350b to have a different polarity as in the previous embodiment.

Accordingly, such a light emitting device can partially secure the light emitting area by forming a part of the first electrode on the light emitting surface and placing the remaining part under the active layer. Even when the current is applied, the current can be uniformly distributed, thereby alleviating the current concentration phenomenon in the high current operation.

As described above, the light emitting device shown in FIGS. 18 and 19 has first and second main surfaces facing each other, and the first and second conductive semiconductor layers providing the first and second main surfaces, respectively, and between them. A semiconductor laminate having an active layer formed thereon, a contact hole connected to a region of the first conductivity-type semiconductor layer from the second main surface through the active layer, and formed on a second main surface of the semiconductor laminate; It can be described as including a first electrode connected through the contact hole in one region of the conductive semiconductor layer, and a second electrode formed on the second main surface of the semiconductor laminate and connected to the second conductive semiconductor layer. have. Here, one of the first and second electrodes may have a structure that is drawn out in the lateral direction of the semiconductor laminate.

The present invention is not limited to the above-described embodiments and the accompanying drawings, but is intended to be limited only by the appended claims. It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

Claims (13)

Providing a wafer having an upper surface on which semiconductor laminates for a plurality of light emitting elements are formed, wherein a plurality of electrodes for the plurality of light emitting elements are formed on the semiconductor laminate;
Grinding the lower surface of the wafer such that the lower surface of the wafer is flattened;
Forming a structure having a predetermined height on the plurality of electrodes;
Forming a wavelength conversion layer made of a resin containing a wavelength conversion material on the semiconductor laminate to cover the structure; And
Polishing the wavelength conversion layer to a desired thickness so that the structure is exposed.
The method of claim 1,
Forming the wavelength conversion layer,
And applying a liquid resin containing the wavelength conversion material on the semiconductor laminate, and curing the liquid resin containing the wavelength conversion material to form the wavelength conversion layer.
3. The method of claim 2,
Between the coating step and the curing step, further comprising the step of accelerating the precipitation of the wavelength conversion material in the liquid resin.
The method of claim 3,
Accelerating the precipitation of the wavelength conversion material,
And maintaining the liquid resin containing the wavelength conversion material at a temperature equal to or higher than the previous process temperature and lower than a curing start temperature.
The method of claim 3,
Accelerating the precipitation of the wavelength conversion material,
Light-emitting device manufacturing method characterized in that the step of maintaining the liquid resin containing the wavelength conversion material at 80 ~ 100 ℃ for at least 5 minutes.
The method of claim 1,
The structure is a photoresist material,
After the polishing, further comprising removing the structure so that the electrode is exposed.
The method of claim 1,
The structure is a light emitting device manufacturing method characterized in that the conductive bump.
The method of claim 1,
And prior to forming the wavelength conversion layer, half dicing a wafer on which the semiconductor stack is formed such that at least the semiconductor stack is separated into individual light emitting devices.
9. The method of claim 8,
The forming of the wavelength conversion layer may include forming the wavelength conversion layer such that a wavelength conversion material is filled in the half dicing region.
The cutting of the wafer may include cutting the wafer such that the wavelength conversion layer is maintained in a side region of the light emitting device obtained by the half dicing.
The method of claim 1,
The wafer is a conductive wafer, the plurality of electrodes is a semiconductor light emitting device manufacturing method, characterized in that formed in each of the light emitting device area one electrode.
Providing a wafer having an upper surface on which semiconductor laminates for a plurality of light emitting elements are formed, wherein a plurality of electrodes for the plurality of light emitting elements are formed on the semiconductor laminate;
Forming a structure having a predetermined height on the plurality of electrodes;
Applying a liquid resin containing the wavelength conversion material on the semiconductor laminate to cover the structure;
Accelerating precipitation of the wavelength conversion material in the liquid resin;
Curing the liquid resin containing the wavelength conversion material to form the wavelength conversion layer; And
Polishing the wavelength conversion layer to a desired thickness so that the structure is exposed.
12. The method of claim 11,
Accelerating the precipitation of the wavelength conversion material,
And maintaining the liquid resin containing the wavelength conversion material at a temperature lower than the curing start temperature while being higher than the previous process temperature.
The method of claim 1,
Accelerating the precipitation of the wavelength conversion material,
Light-emitting device manufacturing method characterized in that the step of maintaining the liquid resin containing the wavelength conversion material at 80 ~ 100 ℃ for at least 5 minutes.

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