JP2018133536A - Encapsulation material, wlp structure optical semiconductor device, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encapsulation material that can increase luminance of an optical semiconductor device manufactured from a wafer level package (WLP).SOLUTION: An encapsulation material (a white encapsulation layer 50) is used for encapsulation of an optical semiconductor element 10 in a wafer level package (WLP) structure, and contains a white pigment, and is liquid.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sealing material used for sealing a wafer-level package (WLP), a WLP structure optical semiconductor device, and a method for manufacturing the same.

  An optical semiconductor device in which an optical semiconductor element such as a light emitting diode (LED) and a phosphor are combined has an advantage of high energy efficiency, long life, and the like. It is applied to various uses such as in-vehicle use, and its demand is expanding.

  In recent years, a technique for manufacturing an optical semiconductor device by WLP has been proposed because of its small size and excellent control of emission color according to applications (for example, Patent Document 1).

JP 2012-195402 A

  Even higher brightness is demanded in optical semiconductor devices having a WLP structure. However, in the method of increasing the light emission amount of the optical semiconductor element itself, there is a concern that the junction temperature rises due to an increase in the heat generation amount of the element and that the element material deteriorates due to a direct increase in light energy.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a sealing material capable of increasing the brightness of an optical semiconductor device manufactured from WLP. It is another object of the present invention to provide a WLP structure optical semiconductor device using such a sealing material and a method for manufacturing the same.

  As a result of intensive studies by the present inventors in order to solve the above problems, it has been found that the light extraction efficiency is not sufficient even in the WLP structure optical semiconductor device including the phosphor disclosed in Patent Document 1. . Then, the present inventors pay attention to a resin layer covering an electrode connected to a semiconductor layer in WLP, and by molding this layer using a sealing material containing a white pigment and having a specific property, The present inventors have found that a semiconductor device having excellent extraction efficiency can be obtained, and have completed the present invention based on this knowledge.

  That is, this invention provides the 1st sealing material which contains a white pigment and is liquid.

  The present invention also provides a second encapsulant that is a liquid that contains a white pigment and is a liquid that is used for encapsulating an optical semiconductor element in a wafer level package (WLP) structure.

  According to the 2nd sealing material of this invention, the white sealing layer which seals the optical semiconductor element in WLP can be favorably formed by having the said structure. The white sealing layer to be formed has a sufficiently high light reflectance in the visible light region, so that the brightness of the optical semiconductor device manufactured from WLP can be increased.

  The present invention also provides a third sealing material which is a sealing material used for compression molding and contains a white pigment and is liquid.

  According to the third sealing material of the present invention, a sealing body having a sufficiently high light reflectance in the visible light region can be obtained by compression molding. By providing such a sealing body adjacent to the optical semiconductor element, the brightness of the optical semiconductor device can be increased.

  The first, second and third sealing materials according to the present invention preferably have a viscosity at 25 ° C. of 10 to 1000 Pa · S from the viewpoint of workability.

  It is preferable that the 1st, 2nd and 3rd sealing material which concerns on this invention contains an epoxy resin from a viewpoint which raises an intensity | strength more.

  The present invention also provides a WLP structure optical semiconductor device comprising a phosphor layer, an optical semiconductor element, and a white sealing layer in this order, wherein the white sealing layer includes a cured product of the sealing material according to the present invention.

  The WLP structure optical semiconductor device of the present invention can have high brightness by including a white sealing layer that is a cured product of the sealing material according to the present invention.

  The present invention also includes a step of forming a plurality of optical semiconductor elements on a substrate, a step of providing an electrode portion on the optical semiconductor element, a white sealing layer so as to cover the optical semiconductor element and the electrode portion, and a wafer level package (WLP). And a method of manufacturing a WLP structure optical semiconductor device in which the white sealing layer includes the cured product of the sealing material according to the present invention. provide.

  According to the method for manufacturing an optical semiconductor device of the present invention, a WLP including a white sealing layer containing a cured product of the sealing material according to the present invention is prepared, and the WLP is singulated to obtain an optical semiconductor device. As a result, an optical semiconductor device capable of increasing the brightness can be efficiently manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, the sealing material which enables the high brightness | luminance of the optical semiconductor device produced from WLP can be provided, WLP structure optical semiconductor device using such a sealing material, and its manufacturing method Can be provided.

FIG. 1 shows a cross-sectional view of an embodiment of a WLP structure optical semiconductor device according to the present invention. FIG. 2 is a process diagram illustrating an embodiment of a method for manufacturing a WLP structure optical semiconductor device according to the present invention. FIG. 3 is a process diagram illustrating one embodiment of a method for manufacturing a WLP structure optical semiconductor device according to the present invention. FIG. 4 is a process diagram illustrating one embodiment of a method for manufacturing a WLP structure optical semiconductor device according to the present invention.

  Hereinafter, embodiments of the present invention will be described in detail.

  In this specification, “WLP (Wafer-Level Package)” indicates a package in which a plurality of optical semiconductor elements are collectively sealed by a single sealing layer, and “WLP structured optical semiconductor device” An optical semiconductor device obtained by dividing the WLP into pieces by means such as dicing is shown. Examples of the configuration of the WLP structure optical semiconductor device include the optical semiconductor device described in Patent Document 1 and the optical semiconductor device described in the embodiments described later, but the present invention is not limited thereto.

  Examples of the optical semiconductor element include a light emitting diode (LED). In this specification, when the optical semiconductor element in WLP is LED, the WLP structure optical semiconductor device obtained from it may be called WLP structure LED.

  In this specification, the thickness of a layer means that at least a part of the layer has the numerical value.

[Encapsulant]
The sealing material which concerns on this embodiment contains a resin component and a white pigment, and is a liquid state. The sealing material according to the present embodiment can be a white sealing material.

  Here, “liquid” means fluidity at room temperature and normal pressure (1 atm, 25 ° C.). More specifically, when the sealing material is tilted by 45 °, it means that the shape cannot be held for 10 minutes or more, and the shape changes. In the present embodiment, from the viewpoint of ease of handling and workability during production use, the sealing material preferably has a viscosity at 25 ° C. of 10 to 1000 Pa · S, more preferably 100 to 900 Pa · S. Preferably, it is more preferably 100 to 700 Pa · S. If the viscosity of the sealing material is 10 Pa · S or more, dripping from the supply nozzle can be further reduced during molding, and if it is 1000 Pa · S or less, the discharge property to the mold can be improved during molding. The viscosity here is a value measured based on JIS Z 8803, and specifically means a value measured by an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., PE-80L). The calibration of the viscometer can be performed based on JIS Z 8809-JS14000.

  The sealing material according to this embodiment that is liquid at 25 ° C. can be suitably used in compression molding. In this specification, compression molding refers to a molding method in which a sealing material is put into a heated mold recess (cavity) and molded by applying pressure and heat.

  In the sealing material of the present embodiment, the resin component can include an epoxy resin and a curing agent.

  As the epoxy resin, an alicyclic epoxy resin and an epoxy resin having an isocyanurate skeleton are preferable. Moreover, it is preferable that an epoxy resin does not have an aromatic ring from a viewpoint which suppresses the fall of the light reflectivity by light irradiation more fully. It is preferable to select an epoxy resin whose cured product has high transparency. The epoxy resin is preferably a resin with relatively little coloring.

  Examples of the alicyclic epoxy resin include 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, 1-epoxyethyl-3,4-epoxycyclohexane, and bis (3,4-epoxycyclohexylmethyl). ) Adipate and the like. As 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate, commercially available products of Celoxide 2021, Celoxide 2021A, and Celoxide 2021P (manufactured by Daicel Chemical Industries, Ltd., trade name) can be used. 1-epoxyethyl-3,4-epoxycyclohexane is Epicoat YX8000, Epicoat YX8034 (above, Japan Epoxy Resin Co., Ltd., trade name), Celoxide 2081, Epolide GT401, EHPE3150 (above, Daicel Chemical Industries, Ltd., Commodity) Name) etc. can be used.

  Preferred alicyclic epoxy resins include 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate and bis (3,4-epoxycyclohexylmethyl) adipate.

  Examples of the epoxy resin having an isocyanurate skeleton include triglycidyl isocyanurate. As the triglycidyl isocyanurate, commercially available products such as TEPIC-PAS (manufactured by Nissan Chemical Industries, Ltd., trade name) can be used.

  Examples of the epoxy resin other than the above include bisphenol F type epoxy resin, bisphenol A type epoxy resin, bisphenol S type epoxy resin, and the like. Commercially available products such as YDF-8170C, Epicoat 828, and YL980 (trade name, manufactured by Japan Epoxy Resin Co., Ltd.) can be used as these resins.

  From the viewpoint of making the sealing material easy to be liquid, the epoxy resin is preferably liquid at room temperature. Examples of such an epoxy resin include 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate and 1-epoxyethyl-3,4-epoxycyclohexane. Among commercially available products, Celoxide 2021, Celoxide 2021A, Celoxide 2021P (above, Daicel Chemical Industries, trade name), Epicoat YX8000, Epicoat YX8034 (above, Japan Epoxy Resin Corporation, trade name), Celoxide 2081, Eporide GT401 (Above, Daicel Chemical Industries, Ltd., trade name).

  An epoxy resin can be used individually by 1 type or in combination of 2 or more types.

  The content of the epoxy resin in the sealing material is preferably 1 to 20% by mass and more preferably 5 to 15% by mass based on the total amount of the sealing material. When the content is 1% by mass or more, a uniform cured product tends to be obtained, and when the content is 20% by mass or less, a decrease in reflectance tends to be sufficiently suppressed.

  The sealing material of this embodiment may contain a thermosetting resin other than an epoxy resin. Examples of thermosetting resins other than epoxy resins include urethane resins, silicone resins, polyester resins, and modified resins thereof. As these thermosetting resins, it is preferable to select those having high transparency of the cured product. These thermosetting resins are preferably those with relatively little coloration.

  The curing agent used in the present embodiment can be used without particular limitation as long as it reacts with the epoxy resin, but a curing agent with relatively little coloring is preferable. Examples of the epoxy resin curing agent include acid anhydride curing agents, isocyanuric acid derivatives, and phenol curing agents.

  In the present embodiment, the curing agent is preferably an acid anhydride curing agent. By using an acid anhydride curing agent as the curing agent, it becomes easy to form a cured product that can sufficiently suppress a decrease in light reflectance due to heating or light irradiation.

  Examples of the acid anhydride curing agent include phthalic anhydride, maleic anhydride, trimellitic anhydride, pyromellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methyl nadic anhydride, nadic anhydride, glutaric anhydride. Acid, dimethylglutaric anhydride, succinic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, norbornene dicarboxylic acid anhydride, methylnorbornene dicarboxylic acid anhydride, norbornane dicarboxylic acid anhydride, methyl norbornane dicuronic acid anhydride Is mentioned.

  Isocyanuric acid derivatives include 1,3,5-tris (1-carboxymethyl) isocyanurate, 1,3,5-tris (2-carboxyethyl) isocyanurate, 1,3,5-tris (3-carboxypropyl) ) Isocyanurate, 1,3-bis (2-carboxyethyl) isocyanurate and the like.

  In this embodiment, among the curing agents described above, phthalic anhydride, trimellitic anhydride, hexahydrophthalic anhydride, tetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, glutaric anhydride, anhydrous It is preferable to use dimethyl glutaric acid, diethyl glutaric anhydride, or 1,3,5-tris (3-carboxypropyl) isocyanurate.

  The curing agent preferably has a molecular weight of 100 to 400 from the viewpoint of moldability and mechanical properties of the cured product. Moreover, as a hardening | curing agent, the acid anhydride which hydrogenated all the unsaturated bonds of the aromatic ring is more preferable than the acid anhydride which has an aromatic ring from a viewpoint of preventing discoloration more. As the acid anhydride curing agent, an acid anhydride generally used as a raw material for the polyimide resin may be used.

  A hardening | curing agent can be used individually by 1 type or in combination of 2 or more types.

  The curing agent is such that the active group (acid anhydride group or hydroxyl group) in the curing agent capable of reacting with the epoxy group is 0.5 to 1.5 equivalents relative to 1 equivalent of the epoxy group in the epoxy resin. It is preferable to mix | blend, and it is more preferable to mix | blend so that it may become 0.7-1.2 equivalent. If the active group is 0.5 equivalents or more, a decrease in the curing rate of the sealing material can be suppressed, and a decrease in the glass transition temperature of the obtained cured body can be suppressed, and a sufficient elastic modulus tends to be obtained. There is. On the other hand, when the active group is 1.5 equivalents or less, a decrease in strength after curing tends to be suppressed.

  From the viewpoint of making the sealing material liquid, the acid anhydride curing agent is preferably liquid at room temperature. Examples of such acid anhydride curing agents include methylhexahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

  The resin component according to the present embodiment can further contain a curing accelerator as necessary. That is, the sealing material according to the present embodiment can further contain a curing accelerator as necessary.

  Examples of the curing accelerator include amine compounds, imidazole compounds, organic phosphorus compounds, alkali metal compounds, alkaline earth metal compounds, and quaternary ammonium salts. Among these curing accelerators, it is preferable to use an amine compound, an imidazole compound, or an organic phosphorus compound.

  Examples of the amine compound include 1,8-diaza-bicyclo [5.4.0] undecene-7, triethylenediamine, and 2,4,6-tris (dimethylaminomethyl) phenol. Examples of the imidazole compound include 2-ethyl-4-methylimidazole. Furthermore, examples of the organic phosphorus compound include triphenylphosphine, tetraphenylphosphonium tetraphenylborate, tetra-n-butylphosphonium-o, o-diethylphosphorodithioate, tetra-n-butylphosphonium-tetrafluoroborate, tetra -N-butylphosphonium-tetraphenylborate.

  A hardening accelerator can be used individually by 1 type or in combination of 2 or more types.

  The blending amount of the curing accelerator is preferably 0.01 to 8 parts by mass and more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the epoxy resin. When the blending amount of the curing accelerator is 0.01 parts by mass or more, a sufficient curing acceleration effect is easily obtained, and when it is 8 parts by mass or less, discoloration of the obtained cured product can be suppressed.

  Examples of white pigments include alumina, magnesium oxide, antimony oxide, titanium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, barium sulfate, magnesium carbonate, barium carbonate, and inorganic hollow particles. Examples of the inorganic hollow particles include sodium silicate glass, aluminum silicate glass, borosilicate soda glass, and shirasu.

  A white pigment can be used individually by 1 type or in combination of 2 or more types.

  Among the above white pigments, alumina, magnesium oxide, antimony oxide, titanium oxide, zirconium oxide, aluminum hydroxide, magnesium hydroxide, and inorganic hollow are in view of thermal conductivity, light reflection characteristics, moldability, and flame retardancy. It is preferable to use one or more selected from the group consisting of particles.

  From the viewpoint of light reflection characteristics, it is preferable to use a white pigment having a large refractive index difference from the epoxy resin. Examples of the white pigment having a large refractive index difference from the epoxy resin include titanium oxide and inorganic hollow particles. Of these, titanium oxide is preferably used.

  The average particle diameter of the white pigment is preferably in the range of 0.1 to 50 μm, and more preferably in the range of 0.1 to 10 μm. When the average particle size is 0.1 μm or more, it becomes easy to prevent the dispersibility from being deteriorated due to aggregation of particles, and when it is 50 μm or less, sufficient light reflection characteristics tend to be obtained. The average particle diameter of the white pigment is measured by a laser beam type particle size distribution analyzer (for example, Beckman Coulter LS 13 320).

  The content (filling amount) of the white pigment in the encapsulant of the present embodiment is preferably 5 to 50% by mass based on the total amount of components that become solid after the encapsulant is cured, and is 10 to 30% by mass. It is more preferable that When this content is 5% by mass or more, sufficient light reflection characteristics are easily obtained, and when it is 50% by mass or less, moldability tends to be maintained and a good molded article tends to be easily produced. is there.

  The sealing material of this embodiment can further contain an inorganic filler other than the white pigment.

Examples of the inorganic filler include silica, barium sulfate, magnesium carbonate, and barium carbonate. From the viewpoint of moldability, the inorganic filler is preferably silica. Moreover, it is preferable that the center particle diameter of an inorganic filler is 1-100 micrometers from a viewpoint of improving packing property with a white pigment. The central particle diameter can be determined as a mass average value D ₅₀ (or median diameter) in particle size distribution measurement by a laser light diffraction method.

  From the viewpoint of moldability, the content (filling amount) of the inorganic filler in the sealing material of the present embodiment is based on the total amount of components that become a solid content after curing of the sealing material. The total amount is preferably 40 to 90% by mass, more preferably 50 to 85% by mass, and particularly preferably 60 to 85% by mass.

  The sealing material of this embodiment can further contain a coupling agent.

  Although it does not specifically limit as a coupling agent, For example, a silane coupling agent and a titanate coupling agent are mentioned. Examples of the silane coupling agent include epoxy silane, amino silane, cationic silane, vinyl silane, acrylic silane, mercapto silane, and composites thereof. The coupling agent can be used in any amount, but the amount of the coupling agent is preferably 5% by mass or less based on the total amount of the sealing material.

  As the other additive, an antioxidant, a light stabilizer, an ultraviolet absorber, a release agent, an ion trapping agent, a flexible material, and the like may be added to the sealing material of this embodiment. Examples of the flexibilizer include acrylic resins, urethane resins, silicone resins, polyester resins, and silicone / caprolactone block copolymers.

  The sealing material of the present embodiment preferably has a light reflectance of 80% or more, more preferably 90% or more with respect to light having a wavelength of 460 nm when the cured material has a thickness of 1 mm. For the cured product having a thickness of 1 mm, a test piece having a thickness of 1 mm ± 0.1 mm is obtained by pressure-molding a sealing material on a hot plate at 150 ° C. and post-curing at 150 ° C. for 2 hours. be able to. The light reflectance can be measured using a spectrocolorimeter (for example, CM-600d, manufactured by Konica Minolta, Inc.).

  From the viewpoint of improving the heat resistant colorability, the sealing material of the present embodiment is preferably such that the light reflectance for light having a wavelength of 460 nm when the cured product is left at 150 ° C. for 200 hours is 70% or more, What becomes 75% or more is more preferable, and what becomes 80% or more is still more preferable.

  From the viewpoint of further increasing the brightness of the optical semiconductor device, the sealing material of the present embodiment preferably has a light reflectance of 80% or more in the entire region of the cured product having a wavelength of 350 to 800 nm, and is 95% or more. It is more preferable that

  From the viewpoint of further improving the heat resistant colorability, the sealing material of this embodiment has a light reflectance of 70% or more in the entire wavelength range of 350 to 800 nm when the cured product is left at 150 ° C. for 200 hours. Is preferable, more preferably 75% or more, and still more preferably 80% or more.

  The light reflection characteristics of the sealing material described above can be realized by appropriately adjusting the blending amounts of various components constituting the sealing material. More specifically, for example, an epoxy resin and a cured product are used. This can be achieved by highly filling the thermosetting resin component and white pigment having a high refractive index.

  According to the sealing material in which the cured product having a thickness of 1 mm has the above-described light reflection characteristics, it is easy to increase the brightness and reduce the size of the WLP structure optical semiconductor device.

  In the sealing material of the present embodiment, the cured product preferably has a linear expansion coefficient (thermal expansion coefficient) in the range from 25 ° C. to the glass transition temperature of 1 to 30 ppm / ° C., and 2 to 20 ppm / ° C. More preferably. When the linear expansion coefficient is within the above range, the reliability of the temperature cycle of the WLP structure optical semiconductor device manufactured by the sealing material can be further improved.

  As for the sealing material of this embodiment, it is preferable that the shrinkage rate of hardened | cured material is -0.1 to 0.5%, and it is more preferable that it is 0 to 0.2%. If it is this range, the curvature of a wafer can be reduced more and reliability can be improved.

  As for the sealing material of this embodiment, it is preferable that the glass transition temperature of hardened | cured material is 50-200 degreeC, and it is more preferable that it is 80-150 degreeC. When the glass transition temperature of the cured product is 50 ° C. or higher, the difference in linear expansion coefficient from other members tends to be small, and peeling from other members is less likely to occur. Moreover, it becomes easy to maintain the melt processability of a sealing material as the glass transition temperature of hardened | cured material is 200 degrees C or less.

  The elastic modulus at 25 ° C. of the cured product is preferably 1 GPa or more, and more preferably 3 GPa or more. Moreover, it is preferable that the elasticity modulus in 25 degreeC of hardened | cured material is 25 GPa or less, and it is more preferable that it is 20 GPa or less. When the elastic modulus is within the above range, it becomes easy to suppress warping of WLP.

  The sealing material of the present embodiment can be obtained by uniformly dispersing and mixing the various components described above, and means and conditions thereof are not particularly limited. For example, when each component is a liquid, a planetary mixer, two rolls, three rolls, a bead mill, a ball mill, and the like can be mentioned, but there is no particular limitation as long as the liquid can be made uniform. Since the work of kneading and removing bubbles in the paste can be performed simultaneously in a short time, a self-revolving vacuum defoaming stirrer may be used.

[WLP]
The WLP of this embodiment includes a phosphor layer, an optical semiconductor element, and a white sealing layer in this order. The white sealing layer may be provided so as to cover at least a part of the optical semiconductor element including the cured product of the sealing material of the present embodiment described above.

  The phosphor layer according to this embodiment is formed in a sheet shape. Although the thickness of a fluorescent substance layer is not limited, 20-500 micrometers is preferable and 50-300 micrometers is more preferable. A fluorescent substance layer can be formed from the fluorescent substance composition containing fluorescent substance and resin, for example.

The phosphor composition is not particularly limited. For example, when a yellow phosphor capable of converting blue light into yellow light is used, a white LED device can be obtained by combining with a blue light emitting diode. Examples of such a phosphor include strontium barium silicon oxide ((Sr, Ba, Eu) ₂ SiO ₄ ) doped with europium. The resin is a matrix in which the phosphor is dispersed. For example, a transparent resin such as a silicone resin, an epoxy resin, or an acrylic resin can be used. From the viewpoint of durability, a silicone resin is preferable.

  The optical semiconductor element can be formed in a predetermined pattern on the upper surface of the phosphor layer. In addition, the optical semiconductor element may include an electrode portion for electrically connecting to the substrate. The electrode portion includes an anode electrode and a cathode electrode, and is formed using, for example, gold or aluminum. The material of the electrode part is preferably gold. The thickness of the anode electrode and the cathode electrode is, for example, 10 to 300 nm, preferably 20 to 200 nm. The electrode portion may be provided with bumps. Examples of the material for forming the bump include conductors such as gold, silver, lead, tin, and alloys thereof (specifically, solder).

  The white sealing layer contains a cured product of the sealing material of the present embodiment, and may be provided so as to cover at least a part of the optical semiconductor element and the electrode part. At least a part of the electrode part is exposed for electrical connection with the substrate. Although the thickness of a white sealing layer is not specifically limited, About 10-2000 micrometers is preferable from a viewpoint of fully coat | covering an optical semiconductor element and an electrode part, and a viewpoint of size reduction.

  From the viewpoint of productivity, 5000 or more optical semiconductor elements are preferably arranged in the WLP of this embodiment, and more preferably 10,000 or more are arranged. As the number of optical semiconductor elements increases, the number of optical semiconductor devices that can be produced at one time can be increased.

[WLP structure optical semiconductor device]
The WLP structure optical semiconductor device of the present embodiment has a structure including a phosphor layer, an optical semiconductor element, and a white sealing layer in this order, and the white sealing layer includes a cured product of the sealing material of the present embodiment. The phosphor layer, the optical semiconductor element, and the white sealing layer can be the same as those described above. The WLP structure optical semiconductor device of this embodiment can be manufactured by, for example, separating the WLP into pieces.

  FIG. 1 is a cross-sectional view showing an embodiment of a WLP structure optical semiconductor device of the present invention. A WLP structure optical semiconductor device 100 shown in FIG. 1 includes a phosphor layer 30, an optical semiconductor element 10 formed on the upper surface of the phosphor layer, and an anode electrode 12 and a cathode electrode 14 connected to the optical semiconductor element 10. The electrode part 16 and the white sealing layer 20 sealed so as to cover the optical semiconductor element 10 and the electrode part 16 are provided.

  The WLP structure optical semiconductor device 100 may further have a configuration in which it is flip-chip mounted on a base substrate.

[Method for Manufacturing WLP Structure Optical Semiconductor Device]
The manufacturing method of the WLP structure optical semiconductor device according to the present embodiment includes a step S1 of forming a plurality of optical semiconductor elements on a substrate, a step S2 of providing an electrode part on the optical semiconductor element, and covering the optical semiconductor element and the electrode part. Step S3 for providing a white sealing layer, and Step S4 for separating the optical semiconductor device from the WLP including the optical semiconductor element and the white sealing layer are provided. The order of the steps is not particularly limited, but the above order is preferable.

(Process S1)
First, a substrate is prepared (FIG. 2A). The substrate 40 may be, for example, a sheet obtained by processing the above-described phosphor layer composition, or a sapphire substrate. When the substrate 40 is the phosphor layer 30, a step of removing the substrate, which will be described later, and a step of forming the phosphor layer on the surface from which the substrate has been removed can be omitted. When the substrate 40 is a sapphire substrate, the rigidity of the substrate is high, so that the work stability is improved. Hereinafter, a case where the substrate 40 is a phosphor layer will be described.

  A plurality of semiconductor elements 10 are formed on the upper surface (one surface in the thickness direction) of the prepared substrate 40 (phosphor layer 30) (FIG. 2B). A plurality of semiconductor elements 10 are formed on the upper surface of the phosphor layer at intervals in the plane direction.

(Process S2)
An electrode portion 16 that is electrically connected to the semiconductor element is provided on the upper surface (one surface in the thickness direction, the side surface opposite to the substrate side in the present embodiment) of each semiconductor element 10 (FIG. 3A). The electrode portion 16 can be formed by a known patterning method. A plurality of electrode portions can be provided corresponding to each semiconductor element. In this embodiment, a pair of anode electrodes and cathode electrodes are provided as electrode portions.

(Process S3)
A white sealing layer 50 is formed on the substrate so as to cover the plurality of optical semiconductor elements 10 and the electrode portions 16 (FIG. 3B). The method of forming the white sealing layer is not particularly limited, for example, a method of applying the sealing material of the present embodiment on the substrate using a laminator, an applicator, etc., and curing by heating or heating and pressing, Alternatively, the white sealing layer can be formed by compression molding or the like.

  In the present embodiment, it is preferable to simultaneously mold and cure the sealing material. For example, when compression molding is performed, the molding temperature is preferably 120 to 180 ° C. as the condition. The molding time is preferably 1 to 15 minutes.

  In the present embodiment, after forming the white sealing layer, the following steps Sa and Sb can be performed in order to obtain a WLP including the optical semiconductor element and the white sealing layer used in step S4.

(Process Sa)
When the portion of the electrode portion that comes into contact with the electrode portion of another substrate in the electrode portion is buried by the step of providing the white sealing layer, the white sealing layer is partially removed so that the end of the electrode portion is exposed. Is preferred. Specifically, in the white sealing layer, the upper part (the part on the opposite side of the white sealing layer from the substrate side) that is above the upper surface of the electrode part is removed. The upper portion of the white sealing layer is removed by flattening the surface using, for example, etching, machining (specifically, grinding), a grinding method, or the like (FIG. 4). (A)).

(Process Sb)
When using a phosphor layer as a substrate as in the present embodiment, it is not necessary to provide this step, but when using a sapphire substrate or the like, it is preferable to provide a step of forming a phosphor layer. In this case, the process of removing a board | substrate from the laminated body in which the white sealing layer was provided, and forming a fluorescent substance layer in the removed surface can be provided. For example, a laser lift-off method can be used for removing the substrate, and the phosphor layer can be formed by using the same method as described above as appropriate. Moreover, when using a sapphire substrate, you may provide a fluorescent substance layer on the surface on the opposite side to the white sealing layer side, without removing the said board | substrate.

  The Shore hardness of the phosphor layer after formation is preferably D50 or more. When the Shore hardness of the resin constituting the phosphor layer is greater than D50, the sagging of the resin can be reduced and the productivity can be improved. Furthermore, a resin layer that does not contain a phosphor may be formed on the phosphor layer. For example, if the refractive index of the resin layer is made smaller than the refractive index of the phosphor layer, the light emission of the optical semiconductor element and the efficiency of taking out the fluorescence of the phosphor layer to the outside can be improved. Further, when the thickness of the phosphor layer is limited by the specification of chromaticity, the thickness of the package can be suitably adjusted by providing the resin layer.

  When the laminate provided on the substrate is transferred to another substrate as in this embodiment, for example, a rigid support substrate such as a silicon substrate is attached to the laminate via a bonding metal such as solder. A technique for joining and holding is widely used. At this time, stress in the bonding process may remain between the laminate and the support substrate. There is also a stress caused by the difference in thermal expansion coefficient between the substrate and the optical semiconductor element. This stress is released when the substrate is removed from the laminate, but at the same time, it may remain as a residual stress between the laminate and the support substrate. These residual stresses cause cracks in the laminate, which is a thin film, or cause the support substrate to bend. For this reason, the flatness of the main surface of the laminate after removing the substrate may be impaired, and it may be difficult to control the thickness of the fluorescent layer formed thereon.

  On the other hand, in the manufacturing method of the WLP structure optical semiconductor device according to the present embodiment, the stacked body after the substrate is removed is formed by the white sealing layer containing the cured product of the sealing material according to the present embodiment. Retained. Since this white sealing layer is flexible and can absorb stress, it becomes easy to maintain the flatness of the laminate, and the controllability of the film thickness of the fluorescent layer formed thereon can be improved. it can.

(Process S4)
The optical semiconductor device is separated into pieces from the WLP (WLP 110 shown in FIG. 4A) according to the present embodiment obtained through the above steps. The optical semiconductor device is cut, for example, by cutting (dicing) the white sealing layer and the phosphor layer between the optical semiconductor elements of the WLP (FIG. 4B). In this way, a plurality of WLP structure optical semiconductor devices 200 are obtained by being individualized (separated).

  As described above, the WLP structure optical semiconductor device according to this embodiment can be manufactured.

  In the present embodiment, the following steps can be further performed on the WLP structure optical semiconductor device obtained above.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to a following example.

[Preparation of sealing material]
(Examples 1 to 3, Comparative Example 1)
The components shown in Table 1 below were blended in the amounts shown in the same table, and kneaded in a self-revolving mixer under conditions of a kneading temperature of 50 ° C. or less and a kneading time of 10 minutes. A stop was obtained. In addition, the number in a table | surface represents a mass part. In the table, the viscosity of the encapsulant at 25 ° C. is measured using an E-type viscometer (manufactured by Tokyo Keiki Co., Ltd., VISCONIC EHD type (trade name)) (cone angle 3 °, rotation speed 10 min ⁻¹ ). Shows the measured value.

The details of each component in Table 1 are as follows.
Epoxy resin 1: triglycidyl isocyanurate (manufactured by Nissan Chemical Industries, Ltd., trade name “TEPIC-PAS”)
Epoxy resin 2: Alicyclic epoxy resin (manufactured by Daicel Chemical Industries, Ltd., trade name “Celoxide 2021P”)
Epoxy resin 3: bisphenol F type epoxy resin (trade name “YDF-8170C” manufactured by Japan Epoxy Resin Co., Ltd.)
Epoxy resin 4: trifunctional epoxy resin (made by Japan Epoxy Resin Co., Ltd., trade name “JER630”)
Curing agent: 3or4-methyl-hexahydrophthalic anhydride (manufactured by Hitachi Chemical Co., Ltd., trade name “HN5500”)
Curing accelerator: Tetra-n-butylphosphonium-o, o-diethyl phosphorodithioate (made by Nippon Chemical Industry Co., Ltd., trade name “PX-4ET”)
Coupling agent: γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”)
Silicone: Both-end modified silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X-22-4952”)
Inorganic filler 1: Silica (manufactured by Nippon Steel & Sumikin Materials Co., Ltd., trade name “ST7010-2”, average particle size 10 μm)
Inorganic filler 2: Silica (manufactured by Admatechs, trade name “SO-25R”, average particle size 0.6 μm)
White pigment: Titanium oxide (Ishihara Sangyo Co., Ltd., trade name "Taipeke PFC107")
Black pigment: Carbon black (trade name “MA-100” manufactured by Mitsubishi Chemical Corporation)

[Evaluation of sealing material]
The obtained sealing material was molded by compression molding (150 ° C., 10 minutes, clamp pressure 100 kN), post-cured at 150 ° C. for 2 hours, and a test piece having a thickness of 1 mm ± 0.1 mm was prepared. Was evaluated. The evaluation results are shown in Table 1.

(Measurement of initial light reflectance)
About the test piece produced by the said method, the light reflectance (%) with respect to the light of wavelength 460nm of the cured film surface was measured using the spectrocolorimeter (CM-600d, Konica Minolta Co., Ltd. product).

(Heat-resistant)
The test piece prepared by the above method was heated at 150 ° C. for 200 hours. About the test piece after a heating, the light reflectance (%) with respect to the light of wavelength 460nm of the cured film surface was measured using the spectrocolorimeter (CM-600d, Konica Minolta Co., Ltd. make).

(Glass transition temperature and coefficient of thermal expansion)
The sealing material is thermoformed into a cylindrical shape having a diameter of 4 mm and a length of 20 mm with a mold temperature of 175 ° C., a molding pressure of 6.9 MPa, a curing time of 300 seconds, and post-curing at 150 ° C. for 2 hours. A test piece was prepared. The thermal expansion amount was measured for the test piece using a thermomechanical analyzer TMA8140 (trade name, manufactured by Rigaku Corporation) at a temperature rising rate of 3 ° C./min and a measurement temperature range of 0 to 250 ° C. The intersection of the tangent line and the tangent line on the high temperature side was defined as the glass transition temperature, and the gradient of the low temperature side straight line as the coefficient of thermal expansion.

(Elastic modulus)
The sealing material was molded into a size of 10 mm × 70 mm × 3 mm by compression molding (150 ° C., 10 minutes, clamp pressure 100 kN), and post-cured at 150 ° C. for 2 hours to prepare a test piece. About the obtained test piece, the bending elastic modulus (MPa) in 25 degreeC was calculated | required by the three-point support type | mold bending test based on JIS-K-6911 using A & D Co., Ltd. tensilon.

(Shrinkage factor)
The sealing material was formed into a size of length 80 mm × width 10 mm × thickness 3 mm by compression molding (150 ° C., 10 minutes, clamp pressure 100 kN), and post-cured at 150 ° C. for 2 hours to obtain a test piece. . From the length of the mold at the molding temperature (175 ° C.) measured in advance and the length of the test piece at room temperature (25 ° C.), the molding shrinkage rate (%) was obtained by the following formula.
Mold shrinkage (%) = [(D−d) / D] × 100
D: Mold cavity length d: Specimen length

<Warpage>
A sealing material was molded on a 300 mm × 300 mm silicon wafer by compression molding (150 ° C., 10 minutes, clamp pressure 100 kN) to a thickness of 150 μm and post-cured at 150 ° C. for 2 hours to obtain a test piece. The amount of warpage at room temperature was measured using a 3D heated surface shape measuring device (manufactured by Akrotrix).

  As is clear from the results shown in Table 1, according to the sealing materials of Examples 1 to 3, it was confirmed that a cured product having a high initial light reflectance and excellent heat discoloration was obtained. By forming the white sealing layer on the WLP with the sealing materials of Examples 1 to 3, it is possible to increase the luminance of the optical semiconductor device manufactured from the WLP and maintain it for a long time.

  DESCRIPTION OF SYMBOLS 10 ... Optical semiconductor element, 12 ... Anode electrode, 14 ... Cathode electrode, 16 ... Electrode part, 20, 50 ... White sealing layer, 30 ... Phosphor layer, 40 ... Substrate, 100 ... WLP structure semiconductor device, 110 ... WLP

Claims (7)

  A sealing material that contains a white pigment and is liquid. A sealing material used for sealing an optical semiconductor element in a wafer level package (WLP) structure,
A sealing material that contains a white pigment and is liquid. A sealing material used for compression molding,
A sealing material that contains a white pigment and is liquid.   The sealing material as described in any one of Claims 1-3 whose viscosity in 25 degreeC is 10-1000 Pa.S.   The sealing material as described in any one of Claims 1-4 containing an epoxy resin. A phosphor layer, an optical semiconductor element, and a white sealing layer are provided in this order,
The WLP structure optical semiconductor device in which the said white sealing layer contains the hardened | cured material of the sealing material as described in any one of Claims 1-5. Forming a plurality of optical semiconductor elements on a substrate;
Providing an electrode portion on the optical semiconductor element;
A step of obtaining a wafer level package (WLP) by providing a white sealing layer so as to cover the optical semiconductor element and the electrode portion; and a step of obtaining a WLP structure optical semiconductor device by dividing the WLP into pieces.
With
The manufacturing method of the WLP structure optical semiconductor device in which the said white sealing layer contains the hardened | cured material of the sealing material as described in any one of Claims 1-5.

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