JP5953797B2 - Manufacturing method of semiconductor light emitting device - Google Patents

Description

  The present invention relates to a semiconductor light emitting device in which a phosphor sheet is covered on a semiconductor light emitting element and a method for manufacturing the same.

  Light emitting diodes (LEDs) are used for backlights of liquid crystal displays (LCDs) and car headlights with low power consumption, long life, and design, etc. due to their remarkable improvement in luminous efficiency. The market is rapidly expanding not only in the automotive field but also for general lighting.

  Since the emission spectrum of an LED depends on the semiconductor material forming the semiconductor light emitting element (hereinafter referred to as the LED chip), its emission color is limited. Therefore, in order to obtain white light for LCD backlight or general illumination using LEDs, it is necessary to arrange phosphors suitable for each chip on the LED chip and convert the emission wavelength. Specifically, a method of installing a yellow phosphor on an LED chip that emits blue light, a method of installing red and green phosphors on an LED chip that emits blue light, and red, green, and blue on an LED chip that emits ultraviolet light A method of installing a phosphor is proposed. Among these, the method of installing a yellow phosphor on a blue LED and the method of installing red and green phosphors on a blue LED are currently most widely adopted in terms of the luminous efficiency and cost of the LED chip. .

  As one of the specific methods for installing the phosphor on the LED chip, a method of attaching a phosphor sheet on the LED chip has been proposed (see, for example, Patent Documents 1 to 3). This method is easier to dispose a certain amount of phosphor on the LED chip than the conventional method of dispensing and curing a liquid resin in which the phosphor is dispersed on the LED chip. The resulting white LED is excellent in that the color and brightness can be made uniform.

JP 2011-233552 A JP 2009-94262 A Japanese Patent No. 2011-222852

  The method of attaching the phosphor sheet to the LED chip is a better method for stabilizing the color and brightness than using the liquid phosphor resin as described above, but includes the problem of difficulty in processing. Yes. There is a possibility that the cutting process for dividing the phosphor sheet into the size of the LED chip may be complicated, and the part corresponding to the electrode part etc. on the LED chip needs to be drilled in advance. is there. Therefore, it is important to develop a phosphor sheet material having excellent processability.

  On the other hand, in a semiconductor light emitting device (hereinafter referred to as an LED device), it is essential that the phosphor sheet completely covers the portion where the LED chip emits light to prevent light leakage from the LED chip, and fluorescence It is economically preferable to minimize the use of the body.

  Patent Document 1 discloses a method of attaching a phosphor sheet to a flip chip mounted LED chip via an adhesive layer. However, in the method disclosed here, since it is difficult to align the phosphor sheet and the LED chip, it may happen that the light emitting portion of the LED chip cannot be completely covered with the phosphor sheet.

  Patent Document 2 discloses a configuration in which a phosphor sheet covers up to a side surface in addition to a light emitting surface of an LED chip. However, in this configuration, the amount of phosphor used increases, so that the cost of the light emitting device increases.

  Further, Patent Document 3 discloses a method of cutting by dicing in a state where a phosphor sheet and an LED chip or a B-stage phosphor sheet and an LED chip are bonded together via an adhesive layer. However, the elastic modulus at room temperature of the adhesive layer and the B-stage phosphor sheet is considered to be low, and the machinability at room temperature is unknown.

  Thus, it has been difficult to obtain an LED device that prevents light leakage from the LED chip and that can minimize the use of phosphors. It is an object of the present invention to provide an LED device that achieves such characteristics.

The present invention is a method for manufacturing a semiconductor light emitting device having a phosphor sheet on the light emitting surface of a semiconductor light emitting element, wherein the storage elastic modulus at 25 ° C. is 0.5 MPa or more and the storage elastic modulus at 100 ° C. A process of affixing a phosphor sheet having a thickness of less than 0.1 MPa to a plurality of semiconductor light emitting elements formed on a circuit board in a batch while heating and simultaneously dividing the plurality of semiconductor light emitting elements into individual pieces It is a manufacturing method of the semiconductor light-emitting device including the process of cut | disconnecting the said fluorescent substance sheet.

  According to the present invention, since the phosphor sheet completely covers the LED chip, light leakage from the LED chip can be prevented. Moreover, since the area of a fluorescent substance sheet can be suppressed, the usage-amount of the fluorescent substance in an LED apparatus can be suppressed to the minimum.

The top view of the state by which the fluorescent substance sheet was laminated | stacked on the LED chip. The side view of the state by which the fluorescent substance sheet was laminated | stacked on the LED chip. The example of the LED device manufacturing process by the resin lamination sheet of this invention.

  The phosphor sheet in the present invention is used by being attached to an LED chip as a wavelength conversion layer. In the flip-chip mounted LED chip, the phosphor sheet is preferably in a state of completely covering the surface of the LED chip. On the other hand, in the LED chip mounted by wire bonding, since the electrode for connecting the wire exists on the surface of the LED chip, the phosphor sheet covers the surface excluding the electrode part of the LED chip more completely. It is preferable. In either LED device, the length m of which the edge of the LED chip is not covered with the phosphor sheet is preferably not more than 5 μm, and more preferably not more than 1 μm.

  The length m in which the edge of the LED chip is not covered with the phosphor sheet means that when a vertical line is drawn from the end of the phosphor sheet to the side of the LED chip on the upper surface of the LED chip as shown in FIG. Is defined as the distance. The length m is preferably not more than 5 μm in the entire periphery of the LED chip, and more preferably not more than 1 μm.

  By covering the surface of the LED chip as described above, light leakage from the LED can be prevented.

  Further, the length n of the edge of the phosphor sheet protruding from the LED chip is preferably not more than 5 μm and more preferably not more than 1 μm in any mounted LED chip.

  The protruding part of the phosphor sheet cannot be expected to contribute to wavelength conversion, and when the phosphor sheet and the LED chip are sealed with a transparent resin, the protruding part of the phosphor sheet is a resin. It is preferable that the protruding length n is shorter, since bubbles may be generated by hindering the sealing of.

  The length n that the edge of the phosphor sheet protrudes from the LED chip is, as shown in FIG. 2, when the LED chip on which the phosphor sheet is laminated is observed from the side surface in each direction, the edge of the phosphor sheet is the LED. It is defined as the length that protrudes from the tip. The length n is preferably not more than 5 μm in the entire periphery of the LED chip, and more preferably not more than 1 μm.

When light leaks from the LED or bubbles are generated inside the LED, the color tone when the LED is turned on changes, which causes variations in the color temperature of the LED. By setting the values of m and n within the above ranges, it is possible to suppress the color temperature variation of the LEDs.
The phosphor sheet used in the LED device of the present invention is not particularly limited as long as it mainly includes a resin and a phosphor, and various sheets can be used. Other components may be included as necessary. The resin used in the present invention is a resin containing a phosphor inside, and finally forms a sheet. Therefore, any resin may be used as long as the phosphor can be uniformly dispersed therein and a sheet can be formed. Specifically, silicone resin, epoxy resin, polyarylate resin, PET modified polyarylate resin, polycarbonate resin, cyclic olefin, polyethylene terephthalate resin, polymethyl methacrylate resin, polypropylene resin, modified acrylic, polystyrene resin, and acrylonitrile / styrene Examples include copolymer resins. In the present invention, a silicone resin or an epoxy resin is preferably used from the viewpoint of transparency. Furthermore, a silicone resin is particularly preferably used from the viewpoint of heat resistance.

  The silicone resin used in the present invention is preferably a curable silicone rubber. Either one liquid type or two liquid type (three liquid type) liquid structure may be used. Examples of the curable silicone rubber include a dealcohol-free type, a deoxime type, a deacetic acid type, and a dehydroxylamine type that cause a condensation reaction with moisture in the air or a catalyst. Moreover, there is an addition reaction type as a type that causes a hydrosilylation reaction with a catalyst. Any of these types of curable silicone rubber may be used. In particular, the addition reaction type silicone rubber is more preferable in that it has no by-product accompanying the curing reaction, has a small curing shrinkage, and can easily be cured by heating.

  As an example, the addition reaction type silicone rubber is formed by a hydrosilylation reaction of a compound containing an alkenyl group bonded to a silicon atom and a compound having a hydrogen atom bonded to a silicon atom. Such materials contain alkenyl groups bonded to silicon atoms such as vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, propenyltrimethoxysilane, norbornenyltrimethoxysilane, octenyltrimethoxysilane, etc. And hydrogen atoms bonded to silicon atoms such as methylhydrogenpolysiloxane, dimethylpolysiloxane-CO-methylhydrogenpolysiloxane, ethylhydrogenpolysiloxane, methylhydrogenpolysiloxane-CO-methylphenylpolysiloxane, etc. Examples thereof include those formed by hydrosilylation reaction of the compounds having them. In addition, for example, known ones as described in JP 2010-159411 A can be used.

  By appropriately designing these resins, the storage elastic modulus at room temperature (25 ° C.) and the storage elastic modulus at high temperature (100 ° C.) can be controlled to obtain a resin useful in the practice of the present invention.

  Moreover, as what is marketed, it is also possible to select and use what has an appropriate storage elastic modulus from the silicone sealing material for general LED use. Specific examples include OE-6630A / B and OE-6520A / B manufactured by Toray Dow Corning.

  In addition, it is possible to add a dispersing agent or leveling agent for stabilizing the coating film as an additive, and an adhesion aid such as a silane coupling agent as a sheet surface modifier. It is also possible to add inorganic particles such as silicone fine particles as a phosphor sedimentation inhibitor.

  It is essential in the present invention that the storage elastic modulus of the phosphor sheet in which the phosphor is dispersed in these resins is 0.5 MPa or more at 25 ° C. and less than 0.1 MPa at 100 ° C. More desirably, it is 0.5 MPa or more at 25 ° C. and less than 0.05 MPa at 100 ° C.

  The storage elastic modulus mentioned here is a storage elastic modulus when dynamic viscoelasticity measurement is performed. Dynamic viscoelasticity means that when shear strain is applied to a material at a sinusoidal frequency, the shear stress that appears when a steady state is reached is divided into a component (elastic component) whose strain and phase match, and the strain and phase are This is a technique for analyzing the dynamic mechanical properties of a material by decomposing it into components (viscous components) delayed by 90 °. Here, what is obtained by dividing the stress component whose phase matches the shear strain by the shear strain is the storage elastic modulus G ′, which represents the deformation and tracking of the material against the dynamic strain at each temperature. It is closely related to processability and adhesion.

  In the case of the phosphor sheet in the present invention, it has a storage elastic modulus of 0.5 MPa or more at 25 ° C., so that it can be used for punching by die punching at room temperature (25 ° C.) or cutting by a blade. Even with a high shear stress, the sheet is punched and cut without surrounding deformation, so that workability with high dimensional accuracy can be obtained. The upper limit of the storage elastic modulus at room temperature is not particularly limited for the purpose of the present invention, but is preferably 1 GPa or less in view of the necessity to propose stress strain after being bonded to the LED element. When the storage elastic modulus of the phosphor sheet is less than 0.5 MPa at 25 ° C., the periphery of the sheet may be deformed in the sheet cutting process. There is a high possibility that the length n protruding from the phosphor sheet at the edge of the semiconductor light emitting element exceeds 5 μm.

  In addition, since the storage elastic modulus is less than 0.1 MPa at 100 ° C., if it is heated and pasted at 60 ° C. to 250 ° C., it quickly deforms and follows the shape of the LED chip surface, and has high adhesive strength. It is obtained. If the phosphor sheet is capable of obtaining a storage modulus of less than 0.1 MPa at 100 ° C., the storage modulus decreases as the temperature is increased from room temperature. However, in order to obtain practical adhesion, 60 ° C. or higher is preferable. In addition, when such a phosphor sheet is heated to a temperature exceeding 100 ° C., the storage elastic modulus further decreases and the sticking property is improved. However, at a temperature exceeding 250 ° C., the resin usually has thermal expansion and thermal contraction. And thermal decomposition problems are likely to occur. Therefore, a suitable heat bonding temperature is 60 ° C to 250 ° C. The lower limit of the storage elastic modulus at 100 ° C. is not particularly limited for the purpose of the present invention, but if the fluidity is too high at the time of heating and pasting on the LED element, the shape processed by cutting or punching before pasting Therefore, it is desirable that the pressure be 0.001 MPa or more.

  As long as the above storage elastic modulus can be obtained as a phosphor sheet, the resin contained therein may be in an uncured or semi-cured state. Then, it is preferable that resin contained is a thing after hardening. If the resin is in an uncured or semi-cured state, the curing reaction proceeds at room temperature during storage of the phosphor sheet, and the storage elastic modulus may be out of the proper range. In order to prevent this, it is desirable that the resin is completely cured, or has been cured to such an extent that the storage elastic modulus does not change for a long period of about one month when stored at room temperature.

  The phosphor absorbs blue light, violet light, and ultraviolet light emitted from the LED chip, converts the wavelength, and emits red, orange, yellow, green, and blue light with wavelengths different from those of the LED chip. To be released. Thereby, a part of the light emitted from the LED chip and a part of the light emitted from the phosphor are mixed to obtain a multicolor LED including white. Specifically, a white LED can be emitted using a single LED chip by optically combining a blue LED with a phosphor that emits a yellow emission color by light from the LED.

  The phosphors as described above include various phosphors such as a phosphor that emits green light, a phosphor that emits blue light, a phosphor that emits yellow light, and a phosphor that emits red light. Specific phosphors used in the present invention include known phosphors such as organic phosphors, inorganic phosphors, fluorescent pigments, and fluorescent dyes. Examples of organic phosphors include allylsulfoamide / melamine formaldehyde co-condensed dyes and perylene phosphors. Perylene phosphors are preferably used because they can be used for a long period of time. Examples of the fluorescent material that is particularly preferably used in the present invention include inorganic phosphors. The inorganic phosphor used in the present invention is described below.

Examples of phosphors that emit green light include SrAl ₂ O ₄ : Eu, Y ₂ SiO ₅ : Ce, Tb, MgAl ₁₁ O ₁₉ : Ce, Tb, Sr ₇ Al ₁₂ O ₂₅ : Eu, (Mg, Ca, Sr , At least one of Ba) and Ga ₂ S ₄ : Eu.

Examples of phosphors that emit blue light include Sr ₅ (PO ₄ ) ₃ Cl: Eu, (SrCaBa) ₅ (PO ₄ ) ₃ Cl: Eu, (BaCa) ₅ (PO ₄ ) ₃ Cl: Eu, (Mg, ₂ B ₅ O ₉ Cl: Eu, Mn, (Mg, Ca, Sr, Ba, at least one) (PO ₄ ) ₆ Cl ₂ : Eu, Mn, etc. .

As phosphors emitting green to yellow, at least cerium-activated yttrium / aluminum oxide phosphors, at least cerium-enriched yttrium / gadolinium / aluminum oxide phosphors, at least cerium-activated yttrium / aluminum There are garnet oxide phosphors and at least cerium activated yttrium gallium aluminum oxide phosphors (so-called YAG phosphors). Specifically, Ln ₃ M ₅ O ₁₂ : R (Ln is at least one selected from Y, Gd, and La. M includes at least one of Al and Ca. R is a lanthanoid series. in _{a), (Y 1-x Ga} x) 3 (Al 1-y Ga y) 5 O 12:. R (R is, Ce, Tb, Pr, Sm , Eu, Dy, at least 1 or more selected from Ho 0 <Rx <0.5, 0 <y <0.5) can be used.

Examples of phosphors that emit red light include Y ₂ O ₂ S: Eu, La ₂ O ₂ S: Eu, Y ₂ O ₃ : Eu, and Gd ₂ O ₂ S: Eu.

As the phosphor corresponding to the current mainstream of the blue LED _{emission, Y 3 (Al, Ga)} 5 O 12: Ce, (Y, Gd) 3 Al 5 O 12: Ce, Lu 3 Al 5 O 12: Ce, Y ₃ Al ₅ O ₁₂ : YAG phosphor such as Ce, TAG phosphor such as Tb ₃ Al ₅ O ₁₂ : Ce, (Ba, Sr) ₂ SiO ₄ : Eu phosphor and Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce phosphor, silicate phosphor such as (Sr, Ba, Mg) ₂ SiO ₄ : Eu, (Ca, Sr) ₂ Si ₅ N ₈ : Eu, (Ca, Sr) AlSiN ₃ : Eu, CaSiAlN ₃ : Nitride phosphor such as Eu, Cax (Si, Al) ₁₂ (O, N) ₁₆ : Oxynitride phosphor such as Eu, and (Ba, Sr, Ca) Si ₂ O ₂ N ₂ : E Examples include phosphors such as u-based phosphors, Ca ₈ MgSi ₄ O ₁₆ Cl ₂ : Eu-based phosphors, SrAl ₂ O ₄ : Eu, and Sr ₄ Al ₁₄ O ₂₅ : Eu.

  Among these, YAG-based phosphors, TAG-based phosphors, and silicate-based phosphors are preferably used in terms of light emission efficiency and luminance.

  In addition to the above, known phosphors can be used according to the intended use and the intended emission color.

  The particle size of the phosphor is not particularly limited, but preferably has a D50 of 0.05 μm or more, more preferably 3 μm or more. Further, those having a D50 of 30 μm or less are preferred, and those having a D50 of 20 μm or less are more preferred. Here, D50 refers to the particle size when the accumulated amount from the small particle size side is 50% in the volume-based particle size distribution obtained by measurement by the laser diffraction / scattering particle size distribution measurement method. When D50 is in the above range, the dispersibility of the phosphor in the phosphor sheet is good, and stable light emission is obtained.

  In the present invention, the phosphor content is preferably 53% by weight or more of the whole phosphor sheet, more preferably 57% by weight or more, and further preferably 60% by weight. By setting the phosphor content in the phosphor sheet within the above range, the light resistance of the phosphor sheet can be improved. The upper limit of the phosphor content is not particularly specified, but is preferably 95% by weight or less of the entire phosphor sheet and 90% by weight or less from the viewpoint that a phosphor sheet excellent in workability can be easily produced. More preferably, it is more preferably 85% by weight or less, and particularly preferably 80% by weight or less.

  The film thickness of the phosphor sheet in the present invention is determined from the phosphor content and desired optical characteristics. Since the phosphor content is limited from the viewpoint of workability as described above, the film thickness is preferably 10 μm or more. Moreover, since the phosphor sheet in the present invention has a large phosphor content, it is excellent in light resistance even when the film thickness is large. On the other hand, from the viewpoint of improving the optical properties and heat resistance of the phosphor sheet, the thickness of the phosphor sheet is preferably 1000 μm or less, more preferably 200 μm or less, and even more preferably 100 μm or less. . By setting the phosphor sheet to a film thickness of 1000 μm or less, light absorption and light scattering by the binder resin can be reduced, so that the phosphor sheet is optically excellent.

  The film thickness of the phosphor sheet in the present invention is a film thickness (average film thickness) measured based on JIS K7130 (1999) plastic-film and sheet-thickness measuring method A for measuring thickness by mechanical scanning. ).

  The heat resistance indicates resistance to heat generated in the LED chip. The heat resistance can be evaluated by comparing the luminance when the LED emits light at room temperature and when the LED emits light at a high temperature, and measuring how much the luminance at the high temperature decreases.

  The LED is in an environment where a large amount of heat is generated in a small space, and particularly in the case of a high power LED, the heat generation is significant. Due to such heat generation, the temperature of the phosphor increases, and the luminance of the LED decreases. Therefore, it is important how efficiently the generated heat is radiated. In this invention, the sheet | seat excellent in heat resistance can be obtained by making a sheet | seat film thickness into the said range. In addition, when the sheet thickness varies, the amount of phosphor varies for each LED chip, and as a result, the emission spectrum (color temperature, luminance, chromaticity) varies. Therefore, the variation in sheet thickness is preferably within ± 5%, more preferably within ± 3%. The film thickness variation referred to here is a thickness measurement method based on a method A of measuring thickness by mechanical scanning in JIS K7130 (1999) plastic-film and sheet-thickness measurement method, and is shown below. Calculated by the formula.

  More specifically, it is obtained by measuring the film thickness using a micrometer such as a commercially available contact-type thickness meter using the measurement conditions of the method A of measuring the thickness by mechanical scanning. The difference between the maximum value or the minimum value of the film thickness and the average film thickness is calculated, and this value is divided by the average film thickness, and the value expressed in 100 minutes is the film thickness variation B (%).

Film thickness variation B (%) = {(maximum film thickness deviation value * −average film thickness) / average film thickness} × 100
* For the maximum film thickness deviation value, the one with the larger difference from the average film thickness is selected from the maximum value or the minimum value.

  A method for producing a phosphor sheet in the present invention will be described. In addition, the following is an example and the preparation method of a fluorescent substance sheet is not limited to this. First, a solution in which a phosphor is dispersed in a resin (hereinafter referred to as “sheet-forming phosphor dispersion”) is prepared as a coating solution for forming a phosphor sheet. The phosphor-dispersing resin for sheet preparation can be obtained by mixing the phosphor and the resin in an appropriate solvent. When an addition reaction type silicone resin is used, when a compound containing an alkenyl group bonded to a silicon atom and a compound having a hydrogen atom bonded to a silicon atom are mixed, the curing reaction may start even at room temperature. It is also possible to extend the pot life by adding a hydrosilylation reaction retarder such as a compound to the phosphor dispersion resin for sheet preparation. It is also possible to mix a dispersion agent and leveling agent for stabilizing the coating film as an additive, and an adhesion aid such as a silane coupling agent as a sheet surface modifier, and the like in the phosphor dispersion resin for sheet preparation. is there. It is also possible to mix alumina fine particles, silica fine particles, silicone fine particles and the like as the phosphor sedimentation inhibitor with the phosphor-dispersing resin for sheet preparation.

  In order to make fluidity appropriate, a solvent can also be added to make a solution. A solvent will not be specifically limited if the viscosity of resin of a fluid state can be adjusted. For example, toluene, methyl ethyl ketone, methyl isobutyl ketone, hexane, acetone, terpineol and the like can be mentioned.

  After preparing these components to a predetermined composition, the mixture is homogeneously mixed and dispersed with a homogenizer, a revolving stirrer, a three-roller, a ball mill, a planetary ball mill, a bead mill, etc. A phosphor-dispersed resin is obtained. Defoaming is preferably carried out under vacuum or reduced pressure conditions after mixing or dispersing.

  Next, the phosphor dispersion resin for sheet preparation is applied on the substrate and dried. Application is reverse roll coater, blade coater, slit die coater, direct gravure coater, offset gravure coater, reverse roll coater, blade coater, kiss coater, natural roll coater, air knife coater, roll blade coater, varibar roll blade coater, toe. A stream coater, rod coater, wire bar coater, applicator, dip coater, curtain coater, spin coater, knife coater or the like can be used. In order to obtain the uniformity of the phosphor sheet thickness, it is preferable to apply with a slit die coater. The phosphor sheet in the present invention can also be produced by using a printing method such as screen printing, gravure printing, and lithographic printing. When using a printing method, screen printing is particularly preferably used.

  The sheet can be dried using a general heating device such as a hot air dryer or an infrared dryer. For heating and curing the sheet, a general heating device such as a hot air dryer or an infrared dryer is used. In this case, the heat curing conditions are usually 40 to 250 ° C. for 1 minute to 5 hours, preferably 100 ° C. to 200 ° C. for 2 minutes to 3 hours.

  As a base material, a well-known metal, a film, glass, a ceramic, paper, etc. can be used without a restriction | limiting in particular. Specifically, metal plates and foils such as aluminum (including aluminum alloys), zinc, copper, iron, cellulose acetate, polyethylene terephthalate (PET), polyethylene, polyester, polyamide, polyimide, polyphenylene sulfide, polystyrene, polypropylene, polycarbonate A film of plastic such as polyvinyl acetal or aramid, a paper laminated with the plastic, or a paper coated with the plastic, a paper laminated or vapor-deposited with the metal, or a plastic film laminated or vapor-deposited with the metal. Can be mentioned. Moreover, when the base material is a metal plate, the surface may be subjected to plating treatment or ceramic treatment such as chromium or nickel. Among these, it is preferable that a base material is a flexible film form from the adhesiveness at the time of sticking a fluorescent substance sheet to an LED element. Further, a film having a high strength is preferred so that there is no fear of breakage when handling a film-like substrate. Resin films are preferred in terms of their required characteristics and economy, and among these, PET films are preferred in terms of economy and handleability. In addition, when a high temperature of 200 ° C. or higher is required when the resin is cured or the phosphor sheet is bonded to the LED, a polyimide film is preferable in terms of heat resistance. The surface of the base material may be subjected to a mold release treatment in advance for ease of peeling of the sheet.

  Although there is no restriction | limiting in particular in the thickness of a base material, 25 micrometers or more are preferable as a minimum, and 40 micrometers or more are more preferable. Moreover, as an upper limit, 1000 micrometers or less are preferable and 500 micrometers or less are more preferable.

  In this invention, when a sheet | seat is affixed on a LED chip, it heats and affixes. The heating temperature is preferably 60 ° C. or higher and 250 ° C. or lower, and more preferably 60 ° C. or higher and 150 ° C. or lower. By setting the temperature to 60 ° C. or higher, the resin design for increasing the difference in elastic modulus between the room temperature and the attaching temperature becomes easy. Moreover, since the thermal expansion and thermal shrinkage of a base material and a fluorescent substance sheet can be made small by setting it as 250 degrees C or less, the precision of bonding can be improved. In particular, when the phosphor sheet is previously punched and aligned with a predetermined portion on the LED element, the positional accuracy of the bonding is important. In order to increase the accuracy of bonding, it is more preferable to bond at 150 ° C. or lower. Furthermore, in order to improve the reliability of the LED device according to the present invention, it is preferable that there is no stress strain between the phosphor sheet and the LED chip. Therefore, the bonding temperature is preferably around the operating temperature of the LED device, preferably within ± 20 ° C. of the operating temperature. When the LED device is lit, the temperature rises from 80 ° C to 130 ° C. Therefore, the bonding temperature is preferably 60 ° C. or higher and 150 ° C. or lower in order to bring the operating temperature and the bonding temperature closer. Therefore, the characteristics of the phosphor sheet designed to sufficiently reduce the storage elastic modulus at 100 ° C. are important.

  In the present invention, since the phosphor sheet itself plays a role as an adhesive layer, it is not necessary to prepare an adhesive layer separately. Moreover, when using an adhesive layer dare, it is preferable to match | combine a fluorescent substance sheet and a storage elastic modulus.

  As a method of attaching the phosphor sheet to the LED chip, the phosphor sheet is cut into individual pieces and then attached to individual LED chips, and the phosphor sheet is attached to a plurality of LED elements such as a wafer level. There is a method of cutting the phosphor sheet at the same time as element dicing, such as wafer dicing, but in the present invention, after the phosphor sheet is attached to a plurality of LED elements, the element pieces are separated. A method of simultaneously cutting the phosphor sheet simultaneously with the conversion is preferably used. By using this method, not only the cutting process can be shortened, but also the alignment of the phosphor sheet and the LED element is not required, so that the values of m and n can be made not to exceed at least 5 μm. Of course, it is possible not to exceed a smaller value, for example, 1 μm, and it is possible to make it substantially 0 if the accuracy is particularly improved. In a process including alignment, there is a high possibility that alignment variations of about 5 to 10 μm will occur.

  Hereinafter, the method will be described in detail using an example using a wafer level LED chip. When affixing phosphor sheets on a wafer level LED chip in a lump, the phosphor sheet is bonded to the LED chip at a high temperature after pasting with a thermocompression tool having a heating part of about 100 mm square. Then, it is allowed to cool to room temperature, and the substrate is peeled off. By providing the relationship between the temperature and the elastic modulus as in the present invention, the phosphor sheet after being allowed to cool to room temperature after heat sealing can be easily peeled off from the substrate while firmly adhering to the LED element. It becomes possible.

  A method for cutting the phosphor sheet will be described. As described above, the phosphor sheet is cut together with the wafer dicing after the phosphor sheet is attached to the wafer-level LED element. Since processing with a laser gives high energy, it is very difficult to avoid scorching of the resin and deterioration of the phosphor, and cutting with a blade is desirable. In order to improve workability when cutting with a blade, it is very important that the storage elastic modulus of the phosphor sheet at 25 ° C. is 0.5 MPa or more. As a cutting method with a blade, there are a method of pushing and cutting a simple blade and a method of cutting with a rotary blade, both of which can be suitably used. As an apparatus for cutting with a rotary blade, an apparatus used for cutting (dicing) a semiconductor substrate called a dicer into individual chips can be suitably used. If the dicer is used, the width of the dividing line can be precisely controlled by the thickness of the rotary blade and the condition setting, so that higher processing accuracy can be obtained than when cutting with a simple cutting tool.

  An example of the process of dicing all together after bonding the phosphor sheet and the wafer is shown in FIG. The process of FIG. 3 includes a process of heating and attaching the phosphor sheet to a plurality of LED elements and a process of dicing the phosphor sheet and the LED element at once. In the process of FIG. 3, the phosphor sheet 1 in the present invention is not cut in advance, and the phosphor sheet 1 side is applied to the wafer 3 provided with the LED elements before dicing as shown in FIG. Align them facing each other. Next, as shown in (b), the phosphor sheet 1 and the LED element wafer 3 before dicing are crimped by the thermocompression bonding tool 6. At this time, it is preferable to perform the pressure bonding step under vacuum or under reduced pressure so that air is not caught between the phosphor sheet 1 and the LED element 3. After the pressure bonding, the substrate 5 is allowed to cool to room temperature. After the substrate 5 is peeled off as shown in (c), the wafer 3 is diced, and at the same time, the phosphor sheet 1 is cut into individual pieces as shown in (d). A singulated LED chip with a phosphor sheet is obtained.

  When the LED chip is mounted on the circuit board by wire bonding, it is desirable to make a hole in the portion in advance before bonding the phosphor sheets in order to remove the phosphor sheet of the electrode portion. . Although known methods such as laser processing and die punching can be suitably used for drilling, laser processing causes burning of the resin and deterioration of the phosphor, so punching with a die is more desirable. When punching is performed, punching cannot be performed after the phosphor sheet is attached to the LED chip. Therefore, it is essential to perform punching before attaching the phosphor sheet. Punching with a mold can open a hole of any shape or size depending on the electrode shape of the LED chip to be bonded. Any size and shape of the hole can be formed by designing the mold, but the electrode joint portion on the LED chip inside and outside the 1 mm square is preferably 500 μm or less in order not to reduce the area of the light emitting surface. The hole diameter is 500 μm or less according to the size. In addition, an electrode for performing wire bonding or the like needs to have a certain size and is at least about 50 μm, so that the hole diameter is about 50 μm in accordance with the size. If the size of the hole is too larger than the electrode, the light emitting surface is exposed, light leakage occurs, and the color characteristics of the LED light emitting device deteriorate. On the other hand, if it is too small than the electrode, the wire touches at the time of wire bonding, resulting in poor bonding. Therefore, in the drilling process, it is necessary to process a small hole having a hole diameter of 50 μm or more and 500 μm or less with high accuracy within ± 10%. In order to improve punching accuracy, the storage elasticity of the phosphor sheet at 25 ° C. It is very important that the rate is 0.5 MPa or more.

  In the case of aligning and bonding the phosphor sheet subjected to perforation processing to the LED element wafer, a bonding apparatus having an optical alignment (alignment) mechanism is required. At this time, it is difficult to align the phosphor sheet and the LED element wafer in terms of work, and in practice, it is often performed to align the phosphor sheet and the LED element wafer in a light contact state. Is called. At this time, if the phosphor sheet has adhesiveness, it is very difficult to move it in contact with the LED element wafer. The phosphor sheet according to the present invention is not sticky if it is aligned at room temperature, so that it is easy to align the phosphor sheet and the LED element wafer in light contact.

  When the LED chip is flip-chip mounted on the circuit board, the bottom surface of the LED chip and the circuit board are joined through bumps or the like, so that it is not necessary to perform the above-described drilling process. Therefore, a process can be shortened rather than the mounting by wire bonding.

  Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these.

<Silicone resin>
Silicone resin 1: OE6520 (Toray Dow Corning Silicone)
Silicone resin 2: OE6630 (Toray Dow Corning Silicone)
Silicone resin 3: X-32-2528 (Shin-Etsu Chemical)
Silicone resin 4: KER6075 (Shin-Etsu Chemical)
<Dynamic elastic modulus measurement>
Measuring device: Viscoelasticity measuring device ARES-G2 (manufactured by TA Instruments)
Geometry: Parallel disk type (15mm)
Strain: 1%
Angular frequency: 1 Hz
Temperature range: 25 ° C to 140 ° C
Temperature increase rate: 5 ° C./min Measurement atmosphere: In the air <Measurement sample adjustment for dynamic viscoelasticity measurement>
30 parts by weight of each of silicone resins 1 to 4 and 70 parts by weight of phosphor “NYAG-02” (manufactured by Intematix: Ce-doped YAG phosphor, specific gravity: 4.8 g / cm ³ , D50: 7 μm) The phosphor sheet resin solution was coated with a “serapeel” BLK (manufactured by Toray Film Processing Co., Ltd.) using a slit die coater to form a film having a thickness of 100 μm. This operation was performed for each of the silicone resins 1 to 4. Film formation temperature is 1 hour at 120 ° C for silicones 1, 2 and 4. Since silicone 3 is a silicone adhesive used in a semi-cured state, it was heated at 120 ° C. for 10 minutes.

  Eight films having a thickness of 100 μm were stacked, and heat-pressed on a 100 ° C. hot plate to produce an integrated film (sheet) having a thickness of 800 μm, and cut into a diameter of 15 mm to obtain a measurement sample.

  Table 1 shows the storage elastic modulus of each sheet (containing 70 wt% phosphor) at room temperature (25 ° C.), 100 ° C., and 140 ° C.

<Adhesion test>
After the phosphor sheet laminated on the substrate is bonded to the LED element at 100 ° C. or 150 ° C. and pressed for a predetermined time, it is returned to room temperature, and when the substrate is peeled off, the phosphor sheet is all adhered to the LED element. The minimum time that does not remain on the substrate was taken as the bondable time. When the thermocompression bonding time is 100 ° C. within 10 minutes, all the phosphor sheets adhere to the LED elements and do not remain on the base material are designated as adhesive A. If the material that adheres within minutes is Adhesive B, and it does not adhere to the LED element even if it is heat-pressed at 150 ° C. for 10 minutes or partially remains on the substrate Adhesiveness C (adhesion failure).

Example 1
Using a polyethylene container having a volume of 300 ml, 30% by weight of silicone resin 1 and “NYAG-02” (manufactured by Intematix, Inc .: Ce-doped YAG phosphor, specific gravity: 4.8 g / cm ³ , D50: 7 μm) was mixed in a proportion of 70% by weight.

  Thereafter, using a planetary stirring and defoaming device “Mazerustar KK-400” (manufactured by Kurabo Industries), stirring and defoaming were carried out at 1000 rpm for 20 minutes to obtain a phosphor-dispersed resin for sheet preparation. Using a slit die coater, the sheet-dispersing phosphor-dispersed resin was applied as a substrate on “Therapy” BLK (manufactured by Toray Film Processing Co., Ltd.), heated at 120 ° C. for 1 hour, and dried to give a film thickness of 90 μm, 100 mm. A corner phosphor sheet was obtained.

  A phosphor sheet of 100 mm square was arranged so that the phosphor sheet surface was in contact with the surface of the blue LED element 4 inch wafer. After returning the sample pressure-bonded with a heating plate at 100 ° C. for 8 minutes from the base material side to room temperature and then peeling off the base material, the phosphor sheet was completely adhered on the blue LED, and the phosphor sheet was attached to the base material. Can be peeled off without leaving any residue, and the adhesiveness was good.

  Next, the wafer of the blue LED element was diced into a size of 1 mm square from the back surface (the surface opposite to the surface on which the phosphor sheet was attached) with a dicing apparatus (manufactured by DISCO). . The cut surface had a good shape with no burrs or chips, and no reattachment of the cut portion occurred.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the edge of each chip sample was observed from above and from the four sides using an SEM, and the phosphor sheet was covered at the edge of the LED element. The length m which is not broken and the length n which the phosphor sheet protrudes at the edge of the LED element were obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  After bonding the LED chip to the substrate through the bumps, create 10 LEDs with the same phosphor sheet sealed with transparent resin, connect them to a DC power source, and check that all 10 LEDs are lit. did. The correlated color temperature (CCT) of all 10 samples was measured with a color illuminometer (Konica Minolta CL200A), and the difference between the maximum value and the minimum value was evaluated as the color temperature variation. The results are shown in Table 2.

(Example 2)
A phosphor sheet was obtained in the same manner as in Example 1. Thereafter, when a hole having a diameter of 200 μm was punched into the phosphor sheet with a die punching device (manufactured by UHT), the punching workability was good. A phosphor sheet of 100 mm square was arranged so that the phosphor sheet surface was in contact with the surface of the blue LED element 4 inch wafer. After aligning the hole of the phosphor sheet and the surface electrode of the LED chip and returning the sample pressure-bonded with a heating plate at 100 ° C. for 8 minutes from the base material side to room temperature, the base material was peeled off. Was completely adhered on the blue LED and could be peeled off cleanly without any phosphor sheet remaining on the substrate, and the adhesion was good.

  Next, the wafer of the blue LED element was diced from the back surface (the surface opposite to the surface on which the phosphor sheet was attached) with a dicing apparatus (manufactured by DISCO). The cut surface had a good shape with no burrs or chips, and no reattachment of the cut portion occurred.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the edge of each chip sample was observed from above and from the four sides using an SEM, and the phosphor sheet was covered at the edge of the LED element. The length m which is not broken and the length n which the phosphor sheet protrudes at the edge of the LED element were obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  After wire bonding the surface electrode of the LED chip, ten LED chips with the same phosphor sheet sealed with a transparent resin were prepared, connected to a DC power source, and turned on, and all 10 were confirmed to be lit. The correlated color temperature (CCT) of all 10 samples was measured with a color illuminometer (Konica Minolta CL200A), and the difference between the maximum value and the minimum value was evaluated as the color temperature variation. The results are shown in Table 2.

Example 3
A phosphor sheet was obtained in the same manner as in Example 1 except that the silicone resin 2 was used instead of the silicone resin 1. A phosphor sheet of 100 mm square was arranged so that the phosphor sheet surface was in contact with the surface of the blue LED element 4 inch wafer. After returning the sample pressure-bonded with a heating plate at 100 ° C. for 8 minutes from the base material side to room temperature and then peeling off the base material, the phosphor sheet was completely adhered on the blue LED, and the phosphor sheet was attached to the base material. Can be peeled off without leaving any residue, and the adhesiveness was good.

  Next, the wafer of the blue LED element was diced from the back surface (the surface opposite to the surface on which the phosphor sheet was attached) with a dicing apparatus (manufactured by DISCO). The cut surface had a good shape with no burrs or chips, and no reattachment of the cut portion occurred.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the edge of each chip sample was observed from above and from the four sides using an SEM, and the phosphor sheet was covered at the edge of the LED element. The length m which is not broken and the length n which the phosphor sheet protrudes at the edge of the LED element were obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  After bonding the LED chip to the substrate through the bumps, create 10 LEDs with the same phosphor sheet sealed with transparent resin, connect them to a DC power source, and check that all 10 LEDs are lit. did. The correlated color temperature (CCT) of all 10 samples was measured with a color illuminometer (Konica Minolta CL200A), and the difference between the maximum value and the minimum value was evaluated as the color temperature variation. The results are shown in Table 2.

(Comparative Example 1)
Using the silicone resin 3 instead of the silicone resin 1, a phosphor-containing silicone resin for sheet preparation is prepared and applied on “Therapy” BLK (manufactured by Toray Film Processing Co., Ltd.) as a base material, and at 120 ° C. for 10 minutes. Heating and drying were performed to obtain a phosphor sheet having a thickness of 90 μm and a square of 100 mm. When a hole having a diameter of 200 μm was punched in the phosphor sheet in the same manner as in Example 2, the silicone resin 3 had a low elasticity at room temperature and was sticky so that it adhered to the mold. The average diameter of the holes was significantly smaller than the design.

  Using the same die bonding apparatus as in Example 2, thermocompression bonding was performed on a blue LED element at 100 ° C. for 10 seconds, the substrate was peeled off, and thermosetting was performed at 150 ° C. for 30 minutes. When the substrate was peeled off after returning to room temperature, the phosphor sheet was completely adhered onto the blue LED, and the phosphor sheet could be removed cleanly without any phosphor sheet remaining on the substrate, and the adhesion was good. It was.

  Next, when the wafer of the blue LED element was diced from the back surface (the surface opposite to the surface on which the phosphor sheet was pasted) with a dicing device (manufactured by DISCO), the cut surface was variably cut. There were about half of the spots where the cut occurred, and some of the cut parts were reattached.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the edge of each chip sample was observed from above and from the four sides using an SEM, and the phosphor sheet was covered at the edge of the LED element. The length m which is not broken and the length n which the phosphor sheet protrudes at the edge of the LED element were obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  When the surface electrode of the LED chip was wire-bonded, the size of the holes processed in advance in the phosphor sheet was small, and some wire bonders were in contact. Ten pieces sealed with resin after wire bonding were prepared and connected to a direct current power source to light up, but three of the ten pieces could not be lit due to poor bonding. Increasing the number of samples produced, obtaining 10 LED light emitting devices with phosphor sheets that light normally, and measuring the correlated color temperature (CCT) of all 10 samples with a color illuminometer (Konica Minolta CL200A) The difference between the maximum value and the minimum value was evaluated as the color temperature variation. As shown in Table 2, the value of m was 5.4 μm, the value of n exceeded 6.1 μm and 5 μm, and as a result, the color temperature variation was as large as 110K.

(Comparative Example 2)
Fabricate a phosphor-containing silicone resin for sheet preparation using silicone resin 4 instead of silicone resin 1, apply it on “Therapy” BLK (manufactured by Toray Film Processing Co., Ltd.), and heat at 120 ° C. for 10 minutes And dried to obtain a phosphor sheet having a thickness of 90 μm and a square of 100 mm.

  Using the same die bonding apparatus as in Example 1, a 100 mm square phosphor sheet was placed so that the phosphor sheet surface was in contact with the surface of a blue LED element 4 inch wafer and thermocompression bonded at 150 ° C. for 10 minutes. When the base film was peeled off after returning to room temperature, the phosphor sheet was incompletely bonded to the blue LED element wafer, and peeled off from the LED element wafer together with the base material, making it impossible to evaluate as an LED chip. there were.

(Comparative Example 3)
A phosphor sheet was obtained in the same manner as in Example 1 using the silicone resin 4 instead of the silicone resin 1. A silicone resin 3 not containing a phosphor is applied on it with a slit die coater, heated at 120 ° C. for 10 minutes and dried to form a 10 μm thick adhesive layer on a 90 μm thick phosphor sheet. A phosphor sheet of the type was obtained.

  A 100 mm square phosphor sheet was placed on the surface of a blue LED element 4 inch wafer and pressed for 8 minutes. When the substrate was peeled off, the phosphor sheet was completely adhered onto the blue LED, and the phosphor sheet could be removed cleanly without any phosphor sheet remaining on the substrate, and the adhesiveness was good.

  Next, when the wafer of the blue LED element was diced from the back surface (the surface opposite to the surface on which the phosphor sheet was pasted) with a dicing device (manufactured by DISCO), the cut surface was variably cut. There were about half of the spots where the cut occurred, and some of the cut parts were reattached.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the edge of each chip sample was observed from above and from the four sides using an SEM, and the phosphor sheet was covered at the edge of the LED element. The length m which is not broken and the length n which the phosphor sheet protrudes at the edge of the LED element were obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  After bonding the LED chip to the substrate through the bumps, create 10 LEDs with the same phosphor sheet sealed with transparent resin, connect them to a DC power source, and check that all 10 LEDs are lit. did. The correlated color temperature (CCT) of all 10 samples was measured with a color illuminometer (Konica Minolta CL200A), and the difference between the maximum value and the minimum value was evaluated as the color temperature variation. As shown in Table 2, the value of m exceeded 5.1 μm, the value of n exceeded 6.3 μm and 5 μm, and as a result, the color temperature variation was as large as 105K.

(Comparative Example 4)
A phosphor sheet was obtained in the same manner as in Example 1. Next, the phosphor sheet was separated into 1 mm square × 10000 pieces using a cutting device (GCUT manufactured by UHT). The phosphor sheet and the substrate were cut together and completely separated. The cut surface had a good shape with no burrs or chips, and no reattachment of the cut portion occurred. The phosphor sheet cut to 1 mm square was arranged so that the phosphor sheet surface was in contact with the chip surface of the substrate on which the blue LED chip previously cut to 1 mm square was similarly mounted. Using a die bonding apparatus (manufactured by Toray Engineering), the phosphor sheet and the surface electrode of the LED chip are aligned and pressed and bonded with a heating head at 100 ° C. from the substrate side. The bonding time is 8 minutes. Met. After returning the sample pressure-bonded for 8 minutes to room temperature and then peeling off the substrate, the phosphor sheet was completely adhered onto the blue LED, and the phosphor sheet could be removed cleanly without any phosphor sheet remaining on the substrate. Adhesion was good.

  For 10 LED chip samples with a 1 mm square phosphor sheet produced in the same manner, the end face of each chip sample was observed from four directions using SEM, and the length m not covered with the phosphor sheet at the edge of the LED element Then, the length n protruding from the phosphor sheet at the edge of the LED element was obtained, and the average value was calculated for 10 samples. The results are shown in Table 2.

  Ten LED with the same phosphor sheet sealed with a transparent resin were prepared, connected to a DC power source and turned on, and it was confirmed that all 10 were turned on. The correlated color temperature (CCT) of all 10 samples was measured with a color illuminometer (Konica Minolta CL200A), and the difference between the maximum value and the minimum value was evaluated as the color temperature variation. As shown in Table 2, the values of m exceeded 6.8 μm and n values exceeded 6.7 μm and 5 μm due to variations in the alignment of the phosphor sheet and the LED chip, resulting in variations in color temperature. Has grown to 115K.

DESCRIPTION OF SYMBOLS 1 Phosphor sheet 2 Length m which is not covered with the phosphor sheet at the edge of the semiconductor light emitting device
3 Wafer 4 Length n that the phosphor sheet protrudes at the edge of the semiconductor light emitting device
5 Base material 6 Thermocompression bonding tool

Claims (2)

A method for manufacturing a semiconductor light emitting device including a phosphor sheet on a light emitting surface of a semiconductor light emitting element, wherein a storage elastic modulus at 25 ° C. is 0.5 MPa or more and a storage elastic modulus at 100 ° C. is 0.1 MPa. A phosphor sheet that is less than less than a plurality of semiconductor light-emitting elements formed on a circuit board while heating, and the phosphor sheets that are collectively separated into individual pieces of the plurality of semiconductor light-emitting elements A method for manufacturing a semiconductor light-emitting device, including a step of cutting the substrate. The method for manufacturing a semiconductor light emitting device according to claim 1 , wherein an adhesive layer is not included between the phosphor sheet and the semiconductor light emitting element.

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