JP5371359B2 - Phosphor-containing glass plate and method for manufacturing light-emitting device - Google Patents

Abstract

The present invention relates to a method for manufacturing the glass plate comprising phosphor and a method for manufacturing a light emitter. The method for manufacturing the light emitter comprises the following steps: mixing the glass powder with the phosphor powder comprising at least one component selected from sulfide phosphor, aluminate phosphor and silicate phosphor thereby preparing the powder mixture of phosphor powder and glass powder; heating and softening the powder mixture for providing an integrated material; solidifying the integrated material for providing the glass dispersed with phosphor; fusing the glass dispersed with phosphor to the installation part which is installed with the light emitting component through hot pressing, and simultaneously sealing the light emitting component on the installation part through the glass dispersed with the phosphor.

Description

  The present invention relates to a method for manufacturing a phosphor-containing glass plate in which phosphors are uniformly dispersed, and a method for manufacturing a light-emitting device that uses this to seal a light-emitting element.

2. Description of the Related Art In recent years, light emitting diode (LED) lamps that emit white light have been put into practical use, and are used for applications such as lighting equipment and backlights of liquid crystal displays.
In general, a white LED lamp is composed of a blue LED chip made of a group III nitride compound semiconductor that emits blue light, and a yellow phosphor that emits yellow wavelength-converted light using light emitted from the LED chip as excitation light. It is manufactured by sealing an LED chip with a transparent resin such as epoxy or silicone containing powder.

Also, in order to obtain higher color rendering than the above-mentioned white LED lamp, there is also a white LED lamp that seals an LED chip by adding a green phosphor powder or a red phosphor powder to a transparent resin in addition to a yellow phosphor powder. Proposed.
JP 2006-253336 A Japanese Patent Laid-Open No. 2002-203989 JP 2003-258308 A

  However, in the conventional white LED lamp, since the transparent resin is used as the sealing material, the transparent resin near the LED chip is yellowed by the light emitted from the LED chip, heat, or the like, and the light extraction efficiency is increased over time. It deteriorates to. In particular, when a short wavelength LED chip that emits blue light or the like having high energy is used, yellowing of the transparent resin appears significantly.

  In addition, since the transparent resin has gas permeability, the fluorescent characteristics of the phosphor powder contained in the transparent resin often deteriorate with time due to reaction with gas (particularly moisture) in the atmosphere. This deterioration in characteristics is prominent in sulfide phosphors, aluminate phosphors, and silicate phosphors that are easily hydrolyzed and inferior in moisture resistance. These phosphors are useful as high-efficiency green phosphors and red phosphors, but it has been difficult to maintain their characteristics for the above reasons.

  As described above, it is difficult to say that sealing with a transparent resin sufficiently satisfies the heat resistance, light resistance, and non-gas permeability characteristics required for an LED lamp.

  In order to solve these problems caused by the transparent resin, a glass-sealed LED lamp that seals the LED chip with a glass having heat resistance, light resistance, and non-gas permeability not developed in the transparent resin has been developed (for example, (See Patent Document 1 and Patent Document 2.)

  In the case of obtaining white light in a glass-sealed LED lamp, a method of incorporating phosphor powder into glass is generally conceivable, as in the case of a transparent resin. In this case, it is desirable to uniformly disperse the phosphor in order to suppress the color unevenness of the light emitted from the LED lamp. However, since glass is highly viscous even at the temperature at which softening begins (deflection point (At)), it is practically difficult to uniformly disperse the phosphor. In order to obtain a low viscosity enough to uniformly disperse the phosphor in the glass, it is necessary to heat to a temperature of about 1000 ° C. However, under such a high temperature, the phosphor and glass react and the phosphor loses its fluorescence characteristics.

  In order to uniformly disperse the phosphor in the glass, glass powder and inorganic phosphor powder are added to a resin binder and mixed, and after forming a preform with a desired shape by pressure molding, the preform is A method of forming a phosphor-containing glass by removing a resin binder while firing has been proposed (see, for example, Patent Document 3). However, in this method, there is a concern that the glass properties such as strength and transparency are deteriorated by the resin binder residue. Moreover, bubbles are generated in the glass due to vaporization of the residue during firing, and gas permeability is obtained. For this reason, it is impossible to suppress the deterioration of the fluorescence characteristics of the phosphor having poor moisture resistance.

  Therefore, it is conceivable to obtain white light by adding phosphor powder to a sol-gel glass precursor (solution consisting of solvent: alcohol, solute: metal alkoxide) that can be formed at a relatively low temperature. However, since the sol-gel glass is porous and has gas permeability, it is impossible to suppress deterioration of the fluorescence characteristics of the phosphor having poor moisture resistance. Moreover, since the sol-gel glass has a large volume change before and after vitrification, cracks occur when a thick film is formed. For these reasons, it is difficult to use as a sealing material that requires a certain film thickness.

  The present invention has been made in view of the above problems, and is capable of preventing the deterioration of a phosphor having poor moisture resistance and manufacturing a light emitting device having excellent heat resistance, light resistance, and non-gas permeability. It aims to provide a method.

In order to achieve the above object, the present invention provides a method for manufacturing a light-emitting device in which a light-emitting element is sealed with a phosphor-containing glass, and the crushed glass obtained by pulverizing ZnO-based glass is passed through a classification water tank. A glass powder generating step for generating a glass powder having a predetermined particle size range in which the upper limit value is 200 μm and is not removed as a supernatant by the water tank; and the glass powder having the predetermined particle size range; Mixing a phosphor powder having at least one of a sulfide phosphor, an aluminate phosphor and a silicate phosphor to produce a mixed powder in which the phosphor powder is dispersed in the glass powder When, the mixed powder after being integrated stably heated and softened at a temperature that does not cause crystallization even with glass ZnO-based phosphor dispersed glass solidifying the mixed powder product That the glass forming process, fusing the single said phosphor dispersion glass mounting portion in which a plurality of light emitting element is mounted by hot pressing, the phosphor dispersion glass the plurality of light emitting elements on the mounting portion A light-emitting device comprising: a glass-sealing step that seals the light-emitting device; and a singulation step that separates the plurality of light-emitting elements sealed with the phosphor-dispersed glass into individual light- emitting devices. A manufacturing method is provided.

  In the light emitting device employing such a manufacturing method, the sulfide phosphor, the aluminate phosphor, and the silicate phosphor having poor moisture resistance are contained in the non-gas-permeable glass. Deterioration of characteristics is suppressed. These phosphors have sufficient heat resistance to the temperature at which the powder glass is integrated by softening, so that the characteristics do not deteriorate due to glass melting. In addition, since the light emitting element is sealed with glass in which these phosphors are uniformly dispersed, color unevenness occurs in the mixed light of the emitted light emitted from the light emitting element and the wavelength converted light emitted from the phosphor. Hateful.

  In said manufacturing method, in the said glass sealing process, a several light emitting element is arrange | positioned on the said mounting part, and after the said glass sealing process, it has an individualization process separated into each light-emitting device. Is preferable in order to improve mass productivity.

  Moreover, it may have a phosphor layer forming step of forming a phosphor layer containing a phosphor different from the phosphor powder on the surface of the glass sealing portion after the glass sealing step or the singulation step. It is preferable because a phosphor having no heat resistance up to the glass melting temperature can be used.

  Furthermore, it further includes a plate-like processing step of processing the phosphor-dispersed glass generated in the glass generation step into a plate shape, and the phosphor-dispersed glass processed into a plate shape in the glass sealing step. Fusing to the flat mounting portion is preferable for improving the mass productivity of the phosphor-dispersed glass.

In order to achieve the above object, the present invention passes the pulverized glass obtained by pulverizing ZnO-based glass through a water tank for classification, and is a particle size that is not removed as a supernatant by this water tank, and its upper limit is 200 μm. A glass powder generating step for generating a glass powder having a predetermined particle size range, a glass powder having the predetermined particle size range, a sulfide phosphor, an aluminate phosphor, and a silicate phosphor. A mixing step of mixing phosphor powder having at least one kind to produce a mixed powder in which the phosphor powder is dispersed in the glass powder, and stably crystallizing the mixed powder using ZnO-based glass A glass generation step for solidifying the mixed powder to produce a phosphor-dispersed glass after heating and softening at a temperature that does not cause crystallization, and a plate-like processing step for forming the phosphor-dispersed glass into a plate shape The No possible to provide a manufacturing method of the phosphor-containing glass plate according to claim.

  In the manufacturing method described above, a phosphor glass plate that is uniformly dispersed can be obtained without losing the fluorescence characteristics of the phosphor.

  According to the method for manufacturing a light emitting device of the present invention, it is possible to obtain a light emitting device excellent in heat resistance, light resistance and non-gas permeability while preventing deterioration of a phosphor having poor moisture resistance.

  1 to 7 show an embodiment of the present invention, FIG. 1 is a sectional view of an LED lamp, and FIG. 2 is a sectional view of an LED chip used in the present embodiment.

  An LED lamp (light emitting device) 1 shown in FIG. 1 includes a flip chip type LED chip (light emitting element) 2, a wiring board 3 on which the LED chip 2 is mounted, a wiring 4 formed on the wiring board 3, and an LED chip. 2 and a glass sealing portion 6 which is bonded to the wiring substrate 3 and contains a phosphor 7.

LED chip 2, as shown in FIG. 2, the surface of the crystal growth substrate 20, a gallium nitride compound semiconductor _{(Al 1-X-Y In} X Ga Y N, 0 ≦ X ≦ 1,0 ≦ Y ≦ 1, A buffer layer 21 composed of 0 ≦ X + Y ≦ 1), an n-type layer 22, a light emitting layer 23, and a p-type layer 24 are sequentially stacked by metal organic vapor phase epitaxy (MOVPE method). Since this LED chip 2 is epitaxially grown at 700 ° C. or higher, the heat resistant temperature is 600 ° C. or higher, and it has a heat resistance of 500 ° C. or higher, which is a processing temperature in sealing processing using low-melting glass. . Further, as the electrodes of the LED chip 2, a p-side electrode 25 provided on almost the entire surface of the p-type layer 24 and a p-side pad electrode 26 provided on a part of the p-side electrode 25 are formed. A predetermined region of the chip 2 is exposed by dry etching from the p-type layer 24 to the n-type layer 22, and an n-side electrode 27 is formed on the n-type layer 22 on the bottom surface. Au bumps 28 are formed on the p-side pad electrode 26 and the n-side electrode 27, respectively.

The crystal growth substrate 20 is made of sapphire (Al ₂ O ₃ ), spinel (MgAl ₂ O ₄ ), gallium nitride (GaN), silicon carbide (SiC), gallium oxide (Ga ₂ O ₃ ), or the like.

The p-side electrode 25 is made of ITO (Indium-Tin-Oxide) having a thermal expansion coefficient equivalent to that of the p-type layer 24. Since ITO has a thermal expansion coefficient equivalent to that of a gallium nitride semiconductor (5 × 10 ⁻⁶ / ° C.), the p-side electrode from the LED chip 2 caused by a difference in thermal expansion coefficient from the LED chip 2 Peeling can be suppressed. A hollow portion 5 (refractive index: about 1.0) that is not filled with glass is formed between the LED chip 2 and the wiring substrate 3. Accordingly, even when ITO (refractive index: about 2.0), which is a transparent conductive material, is used, the difference in refractive index from the hollow portion in contact with the transparent conductive material is large and the critical angle is small. The light is reflected in the direction of the crystal growth substrate 20 at the interface between the hollow portion and ITO.

  The n-side electrode 27 is formed of vanadium (V) / aluminum (Al) / gold (Au). The arrangement of the n-side electrode 27 may be formed at the corner of the LED chip 2 as shown in FIGS. 3 (a) and 4 (a), or as shown in FIGS. 3 (b) and 4 (b). You may form in the center part of one side.

The thermal expansion coefficient (α) of the LED chip 2 is equivalent to the thermal expansion coefficient (α) of the crystal growth substrate that occupies most of the thickness direction. For example, when a sapphire substrate is employed as the crystal growth substrate, the thermal expansion coefficient of the GaN layer of the LED chip 2 is 5 × 10 ⁻⁶ / ° C., but the thermal expansion coefficient of the LED chip 2 as a whole is that of the sapphire substrate. It becomes equivalent to 7 × 10 ⁻⁶ / ° C. equivalent to the rate (α).

The wiring substrate 3 is made of a ceramic substrate such as alumina (Al ₂ O ₃ ), and is formed with a thickness of 0.25 mm and a 1.0 mm square. The thermal expansion coefficient (α) of alumina is 7 × 10 ⁻⁶ / ° C., which is equivalent to the thermal expansion coefficient (α) of the LED chip. As shown in FIG. 1A and FIG. 1C, the wiring 4 of the wiring board 3 is formed on the surface of the board and is electrically connected to the LED chip 2 and on the back surface of the board. And a back surface wiring 42 that can be connected to an external terminal. The front surface wiring 41 and the back surface wiring 42 include tungsten (W) / nickel (Ni) / gold (Au) patterned according to the electrode shape of the LED chip 2. The front surface wiring 41 and the back surface wiring 42 are electrically connected by a via 43 made of W through the wiring substrate 3 in the thickness direction. Each via 43 is diagonally arranged on the wiring board 3 in plan view.

As shown in FIG. 1B, the glass sealing portion 6 is made of ZnO—B ₂ O ₃ —SiO ₂ —Nb ₂ O ₅ —Na ₂ O—Li ₂ O-based low melting glass (hereinafter referred to as this composition). The low-melting-point glass is represented as “low-melting-point glass A”), and one of the phosphors 7 consisting of the green phosphor 7g, the yellow phosphor 7y, and the red phosphor 7r is uniformly dispersed. In FIG. 1B, an enlarged cross-sectional view of the portion A is shown, but the phosphors 7 are uniformly dispersed in any region of the glass sealing portion 6. The green phosphor 7g and the red phosphor 7r are made of a sulfide phosphor, an aluminate phosphor, or a silicate phosphor. Examples of the yellow phosphor 7y include a YAG (Yttrium Aluminum Garnet, Y ₃ Al ₅ O ₁₂ : Ce ³⁺ ) phosphor.

The sulfide phosphor is a phosphor containing sulfur in the matrix of the phosphor, and examples thereof include the following phosphors.
(AE) Ga ₂ S ₄ : Eu ²⁺ green phosphor (AE) S: Eu ²⁺ red phosphor In the above, AE is at least one of Ca and Sr.

The aluminate phosphor is a phosphor having Al ₂ O ₃ as a base, and examples thereof include the following phosphors.
(AE) M ₂ O ₄ : Eu ²⁺ green phosphor In the above, AE is at least one of Ca, Sr, and Ba, and M is at least one of B, Al, and Ga.

Silicate phosphors are phosphors based on SiO ₂ , and examples thereof include the following phosphors.
(AE) ₃ MO ₅ : Eu ²⁺ orange phosphor (AE): At least one of Ca, Sr, and Ba.
In the above, M is at least one of Si and Ge.

As shown in FIG. 1, the glass sealing portion 6 is formed in a rectangular parallelepiped shape on the wiring substrate 3 and has a thickness of 0.5 mm. The side surface 6 a of the glass sealing portion 6 is formed by separating the plate glass bonded to the wiring board 3 by hot press processing together with the wiring board 3 with a dicer. Moreover, the upper surface 6b of the glass sealing part 6 is one surface of the plate glass adhere | attached with the wiring board 3 by the hot press process. This low-melting glass has a glass transition temperature (Tg) of 490 ° C., a yield point (At) of 520 ° C., and a glass transition temperature (Tg) that is sufficiently lower than the formation temperature of the epitaxial growth layer of the LED chip 2. It has become. In this embodiment, the glass transition temperature (Tg) is lower by 200 ° C. or more than the formation temperature of the epitaxial growth layer. Moreover, the thermal expansion coefficient ((alpha)) in 100 to 300 degreeC of low melting glass is 6 * 10 < ^-6 > / ^degreeC . When the thermal expansion coefficient (α) exceeds the glass transition temperature (Tg), a larger numerical value is obtained. As a result, the low-melting glass is bonded to the wiring board 3 at about 600 ° C. and can be hot pressed. Moreover, the refractive index of the low melting glass of the glass sealing part 6 is 1.7.

The composition of the low melting point glass is arbitrary as long as the glass transition temperature (Tg) is lower than the heat resistant temperature of the LED chip 2 and the thermal expansion coefficient (α) is equivalent to that of the wiring board 3. As a glass having a relatively low glass transition temperature and a relatively small coefficient of thermal expansion (α), a ZnO—SiO ₂ —R ₂ O system (where R is at least one selected from alkali metal elements such as Li, Na, and K) is used. ) Glass, phosphate glass and lead glass. Among these glasses, ZnO—SiO ₂ —R ₂ O-based glass has better moisture resistance than phosphoric acid-based glass and does not contain environmentally hazardous substances like lead glass. Material.

Low melting glass is generally processed with a viscosity that is orders of magnitude higher than the level of high viscosity in resins. Furthermore, in the case of glass, the viscosity does not decrease to a general resin sealing level even if the yield point exceeds several tens of degrees Celsius. Further, if the viscosity is set to a level at the time of general resin molding, it will require a temperature exceeding the crystal growth temperature of the LED chip, or will adhere to the mold, making sealing and molding difficult. For this reason, it is preferable to process at 10 ⁴ poise or more.

  Here, the yield point of glass and the coefficient of thermal expansion have a correlation because the factor of the bonding force of the glass acts, and generally, when the yield point is low, the coefficient of thermal expansion increases, Large thermal expansion coefficient. The yield point at which the thermal expansion coefficient (α) of the glass is equivalent to the thermal expansion coefficient of the ceramic substrate (α = 5 ppm / ° C. to 10 ppm / ° C.) is 450 ° C. or higher, and the viscosity is such that the glass can be uniformly dispersed. Therefore, the temperature becomes 1000 ° C. or more, and the fluorescent property of the phosphor is lost. Further, at a temperature at which the glass can be in a solid phase (crystal) state instead of a glass state, it becomes more cloudy due to crystallization as the viscosity becomes higher at a higher temperature. In the present invention, the glass and the phosphor are powdered, and the glass is uniformly dispersed in a softened state with a high viscosity within 200 ° C. from the yield point. It can be set so as not to cause white turbidity.

  The phosphor includes a yellow phosphor 7y, a red phosphor 7r, and a green phosphor 7g. In the present embodiment, a YAG phosphor is used as the yellow phosphor 7y, and a sulfide phosphor, an aluminate phosphor, or a silicate phosphor is used as the red phosphor 7r and the green phosphor 7g. Note that only one of the red phosphor 7y and the green phosphor may be used.

  The manufacturing method of this LED lamp 1 is demonstrated below, referring process explanatory drawing of FIG.

First, the low melting glass A is pulverized and classified by sieving to produce glass powder having a minimum particle size of 20 μm, a maximum particle size of 60 μm, and an average particle size of 30 μm. In addition, the production | generation method of glass powder is mentioned later. Glass transparency This glass powder and a plurality of kinds of phosphors 7r, 7y, 7g having an average particle diameter of 10 μm are mixed at a predetermined ratio, and the phosphor powders 7r, 7y, 7g are uniformly dispersed in the glass powder. Powder 10 is produced. At this stage, a light diffusing powder having an average particle diameter of 20 μm may be added at a predetermined ratio and uniformly dispersed together with the phosphor powders 7r, 7y, and 7g in the glass powder. Examples of the material of the light diffusing powder include zirconia (ZrO ₂ ), alumina (Al ₂ O ₃ ), and silica (SiO ₂ ). When such a light diffusing powder is contained, the light diffusibility in the glass sealing part 6 of the LED lamp 1 is improved, and the mixing of the emitted light of the LED chip 2 and the wavelength converted light of the phosphor 7 is improved. The uneven color of the emitted light from the LED lamp is further suppressed.

  6A and 6B are explanatory views showing a production process and a processing state of the phosphor-dispersed glass. FIG. 6A shows a processing apparatus for producing the phosphor-dispersed glass from the mixed powder, and FIG. 6B shows a fluorescence generated from the mixed powder. (C) shows a state in which the obtained phosphor-dispersed glass has been sliced into a plate shape so as to have a uniform thickness.

First, the mixed powder 10 produced by the mixed powder of glass powder and phosphor powder is melted while applying a load, and then the mixed powder 10 is solidified to produce a phosphor-dispersed glass 11. That is, as shown in FIG. 6A, a cylindrical side surface frame 81 that surrounds a predetermined region on the lower base 80 is provided on the flat upper surface of the lower base 80 to form a concave portion that opens upward. The recess 82 has the same cross section in the vertical direction, and the lower portion of the load jig 83 formed corresponding to the cross-sectional shape of the recess can move up and down in the recess. After the mixed powder 10 is put into the recess, a load jig 83 that pressurizes the recess is set. Then, the air atmosphere is reduced to 7.6 Torr and heated to 650 ° C., and the load jig 83 is used to apply a pressure of 20 kg / cm ² to the mixed powder 10 to soften the glass. The softening conditions for the glass may be normal pressure or no pressure. Thus, it is preferable to soften the glass at a temperature within 200 ° C. from the yield point (At). When the glass is softened at a temperature exceeding this temperature, the glass is crystallized when the glass is solidified, and is easily devitrified. Thereafter, the melted mixed powder 10 is cooled and solidified to disperse the phosphor 7 without causing residual bubbles or white turbidity of an optically affecting size as shown in FIG. 6B. The phosphor-dispersed glass 11 can be obtained. Here, the residual bubbles having a size that affects optically are bubbles having a diameter of 100 μm or more with respect to the LED chip 2 of 300 μm square. There is a possibility that the emitted light re-enters the LED chip 2 and causes a decrease in luminous efficiency. The produced phosphor-dispersed glass 11 is sliced and processed into a plate shape corresponding to the thickness of the glass sealing portion 6 (plate processing step) as shown in FIG. In this embodiment, the thickness of the glass sealing part 6 is 0.5 mm.

  In the present embodiment, no binder is used when the phosphor-dispersed glass 11 is produced. Thereby, the characteristic of glass, such as intensity | strength and transparency, does not deteriorate with the residue of a binder like what bakes mixed powder using a resin binder. Further, when the LED chip 2 is sealed, the airtightness is not impaired by the bubbles.

  The phosphor-dispersed glass 11 thus obtained is dispersed almost uniformly because the phosphor 7 is dispersed before melting. Specifically, any phosphor {10 × (phosphor The average particle width) / (phosphor-containing volume ratio) 1/3} 3, and the phosphor-containing volume ratio is preferably in the range of 50 to 200% with respect to the overall average, and in the range of 80 to 125%. More desirably. The phosphor-dispersed glass 11 actually obtained has a content volume ratio of the phosphors 9 of 9 areas obtained by dividing into 3 equal parts in three orthogonal directions, and is in the range of 80 to 125%. The phosphor 7 is uniformly dispersed. In addition, it is more desirable that the content volume ratio of the phosphor 7 in each area is in the range of 90 to 112%. Here, if necessary, the degree of pulverization of the glass is increased so that the size is equal to that of the phosphor 7 particles, so that the glass can be uniformly dispersed in a more micro area.

  On the other hand, separately from the phosphor-dispersed glass 11, a wiring board 3 with vias 3 a is prepared, and W paste is screen-printed on the surface of the wiring board 3 according to the wiring. Next, the wiring substrate 3 on which the W paste is printed is heat-treated at a temperature of about 1000 ° C. to burn W on the wiring substrate 3, and further, Ni wiring and Au plating are performed on the W to form the wiring 4 (wiring substrate). Forming step). The surface of the polycrystalline alumina may be roughened by omitting the flattening step by polishing when the wiring 4 is refined, and may have a micro unevenness due to the grain boundary of the polycrystalline alumina, or by blasting. What gave the uneven | corrugated formation process may be used.

  Next, the plurality of LED chips 2 are electrically joined to the surface wiring 41 of the wiring 4 of the wiring board 3 by the Au bumps 28 (element mounting process).

Thereafter, the wiring substrate 3 on which each LED chip 2 is mounted is set in the lower mold 91 and the plate-like phosphor-dispersed glass 30 is set in the upper mold 92. A heater is disposed in each of the lower mold 91 and the upper mold 92, and the temperatures of the molds 91 and 92 are independently adjusted. Next, as shown in FIG. 7, the phosphor-dispersed glass 11 is placed on the mounting surface of the substantially flat wiring substrate 3 and hot pressing is performed by pressing the lower mold 91 and the upper mold 92. Thereby, the phosphor dispersed glass 11 is fused to the wiring substrate 3 on which the LED chip 2 is mounted, and the LED chip 2 is sealed on the wiring substrate 3 by the phosphor dispersed glass 11 (glass sealing step). Here, FIG. 7 is a schematic explanatory view showing a state of hot pressing. In the present embodiment, processing was performed by pressurization at about ²⁰ to 40 kgf / cm ² .

Thereby, the fluorescent substance dispersion | distribution glass 30 is adhere | attached through the wiring board 3 and the oxide contained in these. The viscosity of the low-melting glass in hot pressing is preferably 10 ⁵ to 10 ⁷ poise. By setting this viscosity range, it is possible to improve the yield by suppressing bonding of the glass to the upper mold 92 due to low viscosity, glass outflow, etc., and high viscosity. It is possible to suppress a decrease in the bonding strength of glass to the wiring board 3, an increase in the amount of collapse of each Au bump 28, and the like.

  Further, as described above, the surface of the wiring substrate 3 is made of polycrystalline alumina and has a rough surface, and the interface of the bonding portion on the glass sealing portion 6 side is rough along the surface of the wiring substrate 3. It is formed. This is realized by applying pressure during hot press processing and processing in a reduced-pressure atmosphere lower than atmospheric pressure. Here, as long as the glass sufficiently enters the dent of the roughened polycrystalline alumina, the pressure conditions during hot press processing and the pressure reduction conditions of the atmosphere are arbitrary, and pressurization during hot press and pressure reduction of the atmosphere It goes without saying that only one of the above may be performed. As a result, an anchor effect occurs between the glass sealing portion 6 and the wiring substrate 3, and the bonding strength between the glass sealing portion 6 and the wiring substrate 3 can be increased.

  In order to shorten the cycle time of hot pressing, a preheating stage is provided before pressing to heat the glass sealing part 6 in advance, or a slow cooling stage is provided after pressing to control the cooling rate of the glass sealing part 6. You may do it. Moreover, it is also possible to press in a preheating stage and a slow cooling stage, and the process at the time of a hot press process can be changed suitably.

  By obtaining the above steps, an LED lamp precursor 13 as shown in FIG. 7 in a state where a plurality of LED lamps 1 are connected in the vertical and horizontal directions is manufactured. Thereafter, the wiring board 3 integrated with the glass sealing portion 6 is set on a dicer, and each LED chip 2 is diced into individual pieces to complete the LED lamp 1 (individualization step). Both the glass sealing part 6 and the wiring board 3 are cut by a dicer, so that the side surfaces of the wiring board 3 and the glass sealing part 6 are flush with each other.

Further, as shown in FIG. 8, a phosphor layer 8 such as sol-gel glass or silicone resin containing phosphor may be formed in a portion other than the surface where the external connection terminal 44 of the LED lamp 1 is disposed. In this case, a phosphor such as a BOS (Barium Ortho Silicate, Ba ₂ SiO ₄ ) phosphor can be used, and the dimming property of the LED lamp 1 can be improved. When such a phosphor layer is provided, the phosphor 7y does not have to be mixed in the low melting point glass.

  In the LED lamp 1 obtained by such a manufacturing method, when current is passed through the LED chip 2 through the wiring 4, blue light is emitted from the LED chip 2. Part of the blue light emitted from the LED chip 2 is converted into red light, green light, and yellow light by the phosphor 7 in the glass sealing portion 6. Then, these lights are mixed and white light is emitted from the LED lamp.

  Here, since the phosphors 7 are uniformly dispersed in the glass sealing portion 6, the light emitted from the LED chip 2 can be uniformly wavelength-converted regardless of the emitted angle, and the outside. Color unevenness does not occur in the emitted light.

Moreover, since generation | occurrence | production of the bubble in the glass sealing part 6 is suppressed, light is not scattered and reflected in the glass sealing part 6, but light extraction efficiency can be ensured. Moreover, the airtightness of the LED chip 2 is not impaired by the bubbles.

  Here, the particle size of the glass in the mixed powder 10 should be in the range of several μm to 200 μm to avoid mixing of impurities and physical damage during pulverization, suppressing generation of residual bubbles during glass melting, and fluorescence. Desirable for uniformly dispersing the body 7 in the glass. As a result, the phosphor 7 does not exist in a continuous area having a diameter of 300 μm or more.

Moreover, in this embodiment, since the mixed powder 10 was melted while applying a load, the powder can be dissolved at a lower temperature than when no load is applied. In addition, since processing near the yield point (At) is possible, even when an unstable ZnO-based glass is used, crystallization can be prevented stably. The phosphor 7 can be uniformly dispersed even if the glass is melted without applying a load, or the glass may be melted by applying a pressure of 50 kgf / cm ² using a press machine. . In addition, the grade of a pressure-reduced atmosphere and the grade of pressurization can be suitably set according to the characteristic of glass. Further, it is not always necessary to perform both the decompression of the atmosphere and the pressurization to the glass, and it is a matter of course that the glass may be melted under either the decompression atmosphere or the pressurization.

  Moreover, since the low melting glass A is used as the glass sealing part 6, the stability and weather resistance of the glass sealing part 6 can be made favorable. Therefore, even when the LED lamp 1 is used over a long period of time in a harsh environment or the like, the deterioration of the glass sealing portion 6 is suppressed, and the temporal decrease in light extraction efficiency is effectively suppressed. Can do. Furthermore, since the glass sealing part 6 has a high refractive index and a high transmittance characteristic, it is possible to realize both high reliability and high luminous efficiency.

However, even if the low-melting glass A is used, the desired phosphor conversion efficiency may not be obtained. Therefore, the present inventor conducted the following experiment in order to investigate the cause.
A glass powder of low melting glass A classified as a sample was prepared by the following three methods.

  First, glass powders having various compositions as raw materials were prepared so as to have the composition of the low-melting glass A.

  Then, the 1st sample was produced by the following processes. First, the prepared glass powder was melted and then solidified in the atmosphere. Then, the solidified glass was pulverized in the atmosphere by a ball mill so that the maximum particle size was about 100 μm or less, thereby producing a glass powder. Next, a glass powder having a maximum particle size of 60 μm and a minimum particle size of 20 μm was extracted by passing through a 60 μm sieve and a 20 μm sieve.

  In the second and third samples, the prepared glass powder was melted and dropped into room temperature water to produce crushed glass powder by thermal shock. Then, a mixture of glass powder and room temperature water, which was pulverized by a ball mill in a state in which room temperature water was included and was reduced to 60 μm or less with a sieve, was produced. Next, a classification water tank filled with room temperature water was prepared separately from the above water tank. And the mixture of said glass powder and normal temperature water was inject | poured into the water tank for a classification | category, the fine glass powder supernatant was removed, and the glass powder which permeate | transmitted the sieve was extracted. According to such a method, a glass powder having a particle size of about 20 μm or less becomes a supernatant, and thus a glass powder classified into a maximum particle size of 60 μm and a minimum particle size of 20 μm can be extracted.

  Thereafter, the second sample was dried at a temperature of 100 ° C. and a treatment time of 2 hours. The third sample was dried at a temperature of 100 ° C. and a treatment time of 24 hours to completely remove moisture from the glass powder.

Next, using each of the first to third samples, each (Sr, Ca) S: Eu ²⁺ phosphor powder was mixed so that the phosphor powder would be 10 wt% of the total weight of the mixed powder, and then the glass was softened By doing so, three types of phosphor-containing plate-like glass 12 having a thickness of 0.7 mm were prepared.

Then, these three kinds of phosphor-containing plate-like glass 12 are irradiated with the wavelength of blue light (peak wavelength: 450 nm) from the light source to excite the (Sr, Ca) S: Eu ²⁺ phosphor to convert wavelength converted light (peak). Wavelength: 650 nm). Based on the values detected by the output detector 100 for the light from these light sources and the peak wavelength output of the wavelength-converted light, the results of calculating the wavelength conversion efficiency of each phosphor-containing sheet glass 12 are shown. It is shown in 1.

  As apparent from Table 1, it is better to form the phosphor-containing plate glass 12 using the sample 2 and the sample 3 prepared by the wet classification than using the sample 1 prepared by the dry classification. Was found to be obtained. The reason for this is thought to be that in dry classification, glass powder is easily charged with static electricity and impurities are likely to adhere to its surface.

In addition, it can be seen from the results of the phosphor-containing plate-like glass 12 produced by the sample 2 and the sample 3 that it is preferable to sufficiently dry even the sample produced by wet classification.
Accordingly, when producing the phosphor-containing plate-like glass 12, it is desirable to use wet classification of the glass powder as a raw material. More specifically, after using wet classification, moisture is completely removed from the glass powder. Is desirable.

  In addition, since glass having a yield point (At) lower than the epitaxial growth temperature of the semiconductor layer of the LED chip 2 is used as the glass sealing portion 6, the LED chip 2 is not damaged by thermal damage during hot pressing, and the semiconductor. Processing sufficiently lower than the crystal growth temperature of the layer is possible. Furthermore, by setting the plate-like low melting point glass and the wiring board 3 in parallel and hot pressing in a high viscosity state, the low melting point glass moves in parallel to the surface of the wiring board 3 and adheres to the surface, No void is generated to seal the GaN-based LED chip 2.

  Moreover, since the wiring board 3 and the glass sealing part 6 adhere | attach based on the chemical bond through an oxide, stronger sealing strength is obtained. Therefore, even a small package with a small bonding area can be realized.

  Furthermore, since the thermal expansion coefficient (α) of the wiring substrate 3 and the glass sealing portion 6 is the same, adhesion failure such as peeling and cracking is less likely to occur even at room temperature or low temperature after being bonded at high temperature. In addition, cracks are easily generated in the tensile stress in glass, but cracks are not easily generated in the compressive stress, and the glass sealing portion 6 has a slightly smaller thermal expansion coefficient (α) than the wiring substrate 3.

  Furthermore, glass generally has a characteristic that the coefficient of thermal expansion (α) increases at a temperature equal to or higher than the Tg point. When glass sealing is performed at a temperature equal to or higher than the Tg point, not only the Tg point or lower but also the Tg Considering the coefficient of thermal expansion (α) at a temperature equal to or higher than this point is desirable for stable glass sealing. That is, the glass material constituting the glass sealing portion 6 is equivalent in consideration of the thermal expansion coefficient (α) including the thermal expansion coefficient at a temperature equal to or higher than the above Tg point and the thermal expansion coefficient (α) of the wiring board 3. The coefficient of thermal expansion (α) of the substrate suppresses the internal stress that causes warping of the wiring board 3 and the adhesion between the wiring board 3 and the glass sealing portion 6 is obtained. It is possible to prevent shear fracture. Therefore, since the size of the wiring board 3 and the glass sealing part 6 can be increased and a large amount of LED lamps can be produced at once, high mass productivity can be obtained.

  Further, according to the inventor's confirmation, peeling and cracking did not occur even in the liquid phase thermal shock test 1000 cycles at -40 ° C ← → 100 ° C. Furthermore, as a basic confirmation of the bonding of a 5 mm x 5 mm glass piece to a ceramic substrate, an experiment was conducted with various combinations of thermal expansion coefficients (α) for both glass and ceramic substrates. When the ratio of the coefficient of thermal expansion (α) of the lower member to the member of 0.85 is 0.85 or more, it was confirmed that bonding can be performed without causing cracks. Although it depends on the rigidity, size, etc. of the member, the fact that the coefficient of thermal expansion (α) is equal indicates this range.

Further, the inventor conducted the following accelerated deterioration test in order to confirm the effect of the LED lamp of the present embodiment. FIG. 10 is a graph showing the results of the accelerated deterioration test. As a test sample, a red phosphor (sulfide phosphor (CaS: Eu ²⁺ )) added to the LED lamp of the present embodiment and a conventional silicon resin-sealed LED lamp, and a green phosphor (sulfur sulfide). The sample was added with a phosphor (CaGa ₂ S ₄ : Eu ²⁺ )), and a current of 20 mA was applied to the LED chip under high temperature and high humidity of 60 ° C. and 90% humidity. This was done by measuring the maintenance factor of the luminous intensity of the emitted light. In the measurement result of the LED lamp of the present embodiment, as shown in FIGS. 10A and 10B, the luminous intensity of the emitted light is maintained even when the energization time is 3000 hours, but the measurement result of the conventional LED lamp. Then, as shown in FIGS. 10C and 10D, in any of the phosphors, the luminous intensity of the emitted light decreases before the energization time is 1000 hours.

Since the LED chip 2 can be flip-mounted to eliminate the need for a wire, there is no problem with electrodes even when processing in a highly viscous state. The viscosity of the low-melting glass during the sealing process is as hard as 10 ⁴ to 10 ⁸ poise, and the physical properties are greatly different from that of the epoxy resin before the thermosetting treatment is a liquid of about 5 poise. As a result, when sealing a face-up type LED chip in which the electrode on the chip surface and a power supply member such as a lead are electrically connected with a wire, the wire may be crushed or deformed during glass sealing. Can prevent this. In addition, when sealing a flip chip type LED chip in which an electrode on the chip surface is flip-mounted on a power supply member such as a lead through a bump such as gold (Au), the direction of the power supply member is directed to the LED chip based on the viscosity of the glass. Although pressure is applied to the bumps, the bumps may be crushed or a short circuit may occur between the bumps, which can also be prevented.

  Since the front surface wiring 41 of the wiring board 3 is drawn out to the back surface wiring 42 by the via 43, the manufacturing process is not required without requiring special measures to prevent the glass from entering unnecessary portions or covering the electrical terminals. Can be simplified. In addition, since the plate-like phosphor-dispersed glass 11 can be collectively sealed with respect to the plurality of LED chips 2, the plurality of LED lamps 1 can be easily mass-produced by separating them with a dicer. Since low-melting glass is processed in a high-viscosity state, it is not necessary to take sufficient measures against the flow of sealing material like resin, and external terminals are pulled out to the back surface without using vias. If it is sufficient, mass production is possible.

  In addition, the flip mounting of the LED chip 2 has the effect of overcoming the problems in realizing glass sealing and realizing an ultra-small LED lamp 1 of 0.5 mm square. This is because a wire bonding space is not required, and the glass sealing portion 6 and the wiring substrate 3 having the same thermal expansion coefficient member are selected, and the solid bonding based on the chemical bond enables a small space. This is due to the fact that no interfacial delamination occurs even with adhesion.

  Furthermore, since the thermal expansion coefficient (α) of the LED chip 2 and the glass sealing portion 6 is equivalent, the thermal expansion coefficient (α) of the members including the wiring board 3 is equivalent, and high temperature processing and normal temperature in glass sealing are achieved. The internal stress is extremely small even in the temperature difference between and a stable workability without causing cracks. Further, since the internal stress can be reduced, the impact resistance is improved and the glass-sealed LED having excellent reliability can be obtained.

Furthermore, by using the wiring substrate 3 made of alumina, it is possible to reduce the member cost and easily obtain it, so that the mass productivity and the reduction of the device cost can be realized. Further, since the Al ₂ O ₃ is excellent in thermal conductivity, it large amount of light of a certain margin configured for high output. Furthermore, the wiring board 3 is optically advantageous because of its low light absorption.

  In the above-described embodiment, the LED lamp 1 using the gallium nitride compound semiconductor as the LED chip 2 has been described. However, the LED chip is not limited to the GaN-based LED chip 2, for example, zinc selenide. It may be an LED chip made of another semiconductor material such as (ZnSe).

Moreover, what was formed based on the scribing process can be used for the LED chip 2. In this case, the LED chip 2 formed by scribing may have sharp irregularities on the side surface which is a cut portion, and it is desirable to coat the side surface of the LED chip 2 with a chip coating material. As this chip coating material, for example, a light-transmitting SiO ₂ -based coating material can be used. By using the chip coating material, cracks and voids can be prevented during overmolding.

Moreover, although the glass sealing part 6 of said embodiment is excellent in weather resistance, there exists a possibility that the glass sealing part 6 may change in quality, when dew condensation arises according to the use conditions etc. of an apparatus. For this, it is desirable to have a device configuration in which condensation does not occur, but it is also possible to prevent the glass from being deteriorated due to condensation in a high temperature state by applying a silicon resin coat or the like to the surface of the glass sealing portion 6. it can. Furthermore, as a coating material to be applied to the surface of the glass sealing portion 6, an inorganic material such as a SiO ₂ system, an Al ₂ O ₃ system, or the like is preferable as it has not only moisture resistance but also acid resistance and alkali resistance.

1A, 1B, and 1C are cross-sectional views of an LED lamp showing an embodiment of the present invention. FIG. 1A is a cross-sectional view of the entire LED lamp, and FIG. ) Is an enlarged cross-sectional view of part A (glass sealing part) of FIG. 1A, and FIG. 1C is an enlarged cross-sectional view of part B (wiring board) of FIG. It is sectional drawing of the whole lamp | ramp. FIG. 2 is a cross-sectional view of an LED chip using an embodiment of the present invention. FIGS. 3A and 3B are plan views showing electrode forming surfaces of LED chips using the embodiment of the present invention. FIGS. 4A and 4B are top views of the LED lamp showing the formation state of the wiring on the wiring board using the embodiment of the present invention. FIG. 5 is a flowchart showing a method of manufacturing an LED lamp showing an embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating a processing state of the phosphor-dispersed glass according to the embodiment of the present invention. FIG. 6A is a cross-sectional view of a processing apparatus that generates the phosphor-dispersed glass from the mixed powder. The side view of the fluorescent substance dispersion | distribution glass produced | generated from mixed powder is shown, (c) has shown the side view of the state which sliced the obtained fluorescent substance dispersion | distribution glass. FIG. 7 is a flowchart showing a hot press working state according to the embodiment of the present invention. FIG. 8 is a cross-sectional view of an LED lamp that is a modification of the embodiment of the present invention. FIG. 9 is a schematic diagram showing an experimental method for examining the effect of the embodiment of the present invention. 10 (a), (b), (c), and (d) are graphs showing the measurement results of the high-temperature and high-humidity test of the glass-sealed LED lamp of the embodiment of the present invention and the conventional resin-sealed LED lamp. 10 (a) is a graph of the green phosphor-added LED lamp of the present invention, FIG. 10 (b) is a graph of the red phosphor-added LED lamp of the present invention, and FIG. 10 (c) is a conventional graph. FIG. 10D is a graph of a conventional red phosphor-added LED lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LED lamp 2 LED chip 3 Wiring board 4 Wiring 41 Front surface wiring 42 Back surface wiring 43 Via 44 External connection terminal 5 Hollow part 6 Glass sealing part 7 Phosphor 8 Phosphor layer 10 Mixed powder 11 Phosphor dispersion glass 12 Plate-like fluorescence Body-dispersed glass 13 LED lamp precursor 20 Crystal growth substrate 21 Buffer layer 22 N-type layer 23 Light-emitting layer 24 p-type layer 25 p-side electrode 26 p-side pad electrode 27 n-side electrode 28 Au bump 80 Lower base 81 Side frame 82 Recess 83 Load jig 91 Lower mold 92 Upper mold 100 Output detector

Claims (6)

In a method for manufacturing a light emitting device in which a light emitting element is sealed with phosphor-containing glass,
A glass powder obtained by pulverizing ZnO-based glass through a water tank for classification and having a particle diameter that is not removed as a supernatant by the water tank and that has an upper limit of 200 μm and having a predetermined particle diameter range. A glass powder production process to produce;
The glass powder having the predetermined particle size range is mixed with phosphor powder having at least one of sulfide phosphor, aluminate phosphor and silicate phosphor, and the phosphor powder is mixed with the glass. A mixing step for producing a mixed powder dispersed in the powder;
A glass production process in which the mixed powder is heated and softened at a temperature at which stable crystallization does not occur even if ZnO-based glass is used and then integrated, and then the mixed powder is solidified to produce a phosphor-dispersed glass. When,
Fusing the single said phosphor dispersion glass mounting portion in which a plurality of light emitting element is mounted by hot pressing, a sealed glass for sealing by the phosphor dispersion glass the plurality of light emitting elements on the mounting portion Stop process ,
A method of manufacturing a light-emitting device, comprising: a step of dividing the plurality of light-emitting elements sealed with the phosphor-dispersed glass into individual light-emitting devices . A phosphor layer forming step of forming a phosphor layer containing a phosphor different from the phosphor powder on the surface of the glass sealing portion after the glass sealing step or the singulation step is characterized in that The manufacturing method of the light-emitting device of Claim 1 . The method further includes a plate-like processing step of processing the phosphor-dispersed glass generated in the glass generation step into a plate shape, and the phosphor-dispersed glass processed into a plate shape in the glass sealing step is flat. method of manufacturing a light-emitting device according to claim 1 or claim 2, characterized in that fusing the mounting portion.   The method for manufacturing a light-emitting device according to claim 1, wherein the glass powder generation step includes a wet classification step of wet-classifying the pulverized glass and a drying step of drying the wet-classified glass powder. A glass powder obtained by pulverizing ZnO-based glass through a water tank for classification and having a particle diameter that is not removed as a supernatant by the water tank and that has an upper limit of 200 μm and having a predetermined particle diameter range. A glass powder production process to produce;
The glass powder having the predetermined particle size range is mixed with phosphor powder having at least one of sulfide phosphor, aluminate phosphor and silicate phosphor, and the phosphor powder is mixed with the glass. A mixing step for producing a mixed powder dispersed in the powder;
A glass production process in which the mixed powder is heated and softened at a temperature at which stable crystallization does not occur even if ZnO-based glass is used and then integrated, and then the mixed powder is solidified to produce a phosphor-dispersed glass. When,
The manufacturing method of the fluorescent substance containing glass plate characterized by including the plate-shaped process process which makes the said fluorescent substance dispersion | distribution glass into plate shape. 6. The phosphor-containing glass plate according to claim 5 , wherein the glass powder generation step includes a wet classification step of wet-classifying the pulverized glass and a drying step of drying the wet-classified glass powder. Production method.

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