JP6963214B2 - Glass powder and sealing material using it - Google Patents

Description

The present invention relates to a glass powder and a sealing material using the same, and particularly to a glass powder suitable for a sealing treatment by laser light (hereinafter, laser sealing) and a sealing material using the same.

In recent years, an organic EL display has been attracting attention as a flat display panel. Conventionally, an organic resin-based adhesive having low-temperature curability has been used as an adhesive material for an organic EL display. However, since the organic resin adhesive cannot completely block the infiltration of gas and moisture, the active element and the organic light emitting layer having low water resistance are liable to deteriorate, and the display characteristics of the organic EL display deteriorate over time. Was occurring.

On the other hand, the sealing material containing the glass powder is less likely to allow gas or moisture to permeate than the organic resin adhesive, so that the airtightness inside the organic EL display can be ensured.

However, since the glass powder has a higher softening temperature than the organic resin adhesive, there is a risk that the active element and the organic light emitting layer are thermally deteriorated at the time of sealing. Under these circumstances, laser sealing is drawing attention. According to laser sealing, it is possible to locally heat only the part to be sealed, and the sealed object such as a non-alkali glass substrate can be sealed without thermally deteriorating the active element or the organic light emitting layer. can do.

Further, in addition to the above-mentioned organic EL display, it is being studied to maintain the characteristics of the airtight package and extend the service life. For example, in an airtight package on which an LED element is mounted, a low-temperature firing substrate (LTCC) having aluminum nitride and thermal vias is used as the substrate from the viewpoint of thermal conductivity. In this case as well, the substrate and the lid (lid) are used. ) Is preferably laser-sealed. In particular, in an airtight package in which an LED element that emits light in the ultraviolet wavelength region is mounted, it becomes easy to maintain the emission characteristics in the ultraviolet wavelength region by laser sealing. Further, it is possible to prevent thermal deterioration of the LED element by laser sealing.

U.S. Pat. No. 6416375 Japanese Unexamined Patent Publication No. 2006-315902

According to the research by the present inventor, the fluidity of the sealing material is important for laser sealing. When the fluidity of the sealing material is high, the laser sealing strength is improved, and airtight leakage or the like is less likely to occur due to mechanical impact or the like. Then, in order to improve the fluidity of the sealing material, it is effective to lower the melting point of the sealing material.

However, in order to increase the fluidity of the sealing material, it is necessary to increase the content of the refractory filler powder or increase the softening component in the glass powder, and the coefficient of thermal expansion of the sealing material increases. It becomes easier to do. As a result, it becomes difficult to match the coefficient of thermal expansion of the sealed object such as the non-alkali glass substrate, the aluminum nitride substrate, and the LTCC, cracks occur in the sealed object and the sealing material layer, and it becomes difficult to ensure airtightness. ..

Therefore, the present invention has been made in view of the above circumstances, and the technical problem thereof is to devise a glass powder having high fluidity at the time of laser sealing and a low coefficient of thermal expansion and a sealing material using the same. By doing so, it is possible to suppress deterioration of the characteristics of the organic EL display, the airtight package, and the like.

As a result of diligent studies, the present inventor has found that the above technical problems can be solved by strictly regulating the glass composition range of the glass powder, and proposes the present invention. That is, the glass powder of the present invention has a glass composition of Bi ₂ O ₃ + CuO 83 to 95%, Bi ₂ O ₃ 75 to 90%, B ₂ O ₃ 3 to 12%, ZnO 1 to 10% in terms of glass composition. , Al ₂ O _{30 to} 5%, CuO 4 to 15%, Fe ₂ O _{30 to} 5%, MgO + CaO + SrO + BaO 0 to 7%, and is characterized in that it contains substantially no PbO. Here, "Bi ₂ O ₃ + CuO" refers to the total amount of _{Bi 2} O _{3 and CuO.} "MgO + CaO + SrO + BaO" refers to the total amount of MgO, CaO, SrO and BaO. "Substantially free of PbO" refers to a case where the content of PbO in the glass composition is less than 0.1% by mass.

According to the investigation by the present inventor, the _{total amount of Bi 2} O ₃ and Cu O has a great influence on increasing the fluidity at the time of laser sealing. The glass powder of the present invention has a Bi ₂ O ₃ + CuO content of 83 to 95% by mass in the glass composition. If _{the content of Bi 2} O ₃ + CuO is regulated to 83% by mass or more, the fluidity at the time of laser sealing can be improved. On the other hand, if _{the content of Bi 2} O ₃ + CuO is regulated to 95% by mass or more, the glass is devitrified at the time of laser sealing, and it becomes easy to secure the desired fluidity.

Further, the glass powder of the present invention has a CuO content of 4 to 15% by mass in the glass composition. When the CuO content is regulated to 4% by mass or more, the light absorption characteristics are improved, so that the fluidity at the time of laser sealing can be improved. On the other hand, if the CuO content is restricted to 15% by mass or less, the glass is less likely to be devitrified during laser sealing.

Further, the glass powder of the present invention has a ZnO content of 1 to 10% by mass in the glass composition. If the ZnO content is regulated to 1% by mass or more, the coefficient of thermal expansion can be reduced. On the other hand, if the ZnO content is restricted to 10% by mass or less, when the Bi ₂ O ₃ + CuO content is 83% by mass or more, the glass is less likely to be devitrified during laser sealing.

Further, the glass powder of the present invention has a content of MgO + CaO + SrO + BaO in the glass composition of 7% by mass or less. If the content of MgO + CaO + SrO + BaO is regulated to 7% by mass or less, the coefficient of thermal expansion tends to be lowered while ensuring the fluidity at the time of laser sealing.

The glass powder of the present invention does not substantially contain PbO in the glass composition. In this way, it is possible to meet the environmental demands of recent years.

Secondly, the glass powder of the present invention preferably has a ZnO content of less than 1 to 5% by mass.

Third, the glass powder of the present invention preferably has a mass ratio (Bi ₂ O ₃ + CuO) / ZnO of 15 to 70. Here, "(Bi ₂ O ₃ + CuO) / ZnO" refers to a value obtained by dividing the total amount of _{Bi 2} O _{3 and CuO by the content of ZnO.}

Fourth, the glass powder of the present invention preferably has a content of MgO + CaO + SrO + BaO of less than 0 to 2.0% by mass. In this way, the coefficient of thermal expansion can be reliably reduced while ensuring good fluidity during laser sealing. As a result, long-term reliability after laser sealing can be improved.

Fifth, in the sealing material containing the glass powder and the fire-resistant filler powder, the sealing material of the present invention is the above-mentioned glass powder, and the content of the glass powder is 50 to 95% by volume. , The content of the fire resistant filler powder is preferably 5 to 50% by volume.

Sixth, in the sealing material of the present invention, the refractory filler powder is cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, β-. It is preferably one or more selected from quartz solid solution and spojumen. These refractory filler powders have good compatibility with the above glass powders and have low thermal expansion. Therefore, when these refractory filler powders are used, the coefficient of thermal expansion of the sealing material can be lowered so as to match the coefficient of thermal expansion of the object to be sealed without devitrifying the glass powder at the time of sealing.

Seventh, the sealing material of the present invention preferably further contains 0 to 25% by volume of a laser absorber.

Eighth, in the sealing material of the present invention, the laser absorber is one or more selected from Cu-based oxides, Fe-based oxides, Cr-based oxides, Mn-based oxides and composite oxides thereof. Is preferable. In this way, the laser light can be easily converted into heat energy, so that the laser sealing strength can be increased. Here, the “~ system oxide” refers to an oxide containing an explicit component as an essential component.

Ninth, the sealing material of the present invention is preferably used for laser sealing. By doing so, since the sealing material layer can be locally heated, it is possible to prevent thermal deterioration of the element having low heat resistance. The light source of the laser light used for laser sealing is not particularly limited, but for example, a semiconductor laser, a YAG laser, a CO ₂ laser, an excimer laser, an infrared laser and the like are suitable because they are easy to handle. Further, the emission center wavelength of the laser light is preferably 500 to 1600 nm, particularly preferably 750 to 1300 nm in order for the sealing material to accurately absorb the laser light.

It is the schematic sectional drawing for demonstrating one Embodiment of the airtight package which concerns on this invention.

The glass powder of the present invention has a glass composition of Bi ₂ O ₃ + CuO 83 to 95%, Bi ₂ O ₃ 75 to 90%, B ₂ O ₃ 3 to 12%, ZnO 1 to 10%, Al. _{It is characterized by containing 2} O _{30 to} 5%, CuO 4 to 15%, Fe ₂ O _{30 to} 5%, MgO + CaO + SrO + BaO 0 to 7%, and substantially no PbO. The reasons for limiting the glass composition range of the glass powder as described above are shown below. In the description of each glass component,% notation indicates mass%.

The _{total amount of Bi 2} O ₃ and Cu O has a great influence on increasing the fluidity at the time of laser sealing. The content of Bi ₂ O ₃ + CuO is 83 to 95%, preferably 85 to 92%, particularly 87 to 91%. If _{the content of Bi 2} O ₃ + CuO is too small, the glass does not sufficiently soften and flow even when irradiated with laser light, and it becomes difficult to secure the laser sealing strength. However, if _{the content of Bi 2} O ₃ + CuO is too large, the glass will be devitrified during laser sealing, and the desired fluidity cannot be secured.

Bi ₂ O ₃ is a main component for lowering the softening point, and its content is 75 to 90%, preferably 76 to 86%, more preferably more than 77 to 84%, still more preferably 78 to 82. %. If _{the content of Bi 2} O ₃ is too small, the softening point becomes too high, and it becomes difficult for the glass to soften even when irradiated with laser light. On the other hand, if _{the content of Bi 2} O ₃ is too large, the glass becomes thermally unstable, and the glass tends to be devitrified at the time of laser sealing.

B ₂ O ₃ is a component forming a glass network, and its content is 3 to 12%, preferably 4 to 10%, and more preferably 5 to 9%. If _{the content of B 2} O ₃ is too small, the glass becomes thermally unstable, and the glass tends to be devitrified during laser sealing. On the other hand, if _{the content of B 2} O ₃ is too large, the softening point becomes too high, and even if the glass is irradiated with laser light, it becomes difficult for the glass to soften.

ZnO is a component that lowers the coefficient of thermal expansion. The ZnO content is 1-10%, preferably 2-7%, 2.5-6%, particularly less than 3-5%. If the ZnO content is too low, the coefficient of thermal expansion tends to be high. On the other hand, if the content of ZnO is too large _{, the glass becomes thermally unstable when the content of Bi 2} O ₃ + CuO is 83% or more, and the glass tends to be devitrified at the time of laser sealing.

The mass ratio (Bi ₂ O ₃ + CuO) / ZnO is preferably 15 to 70, 20 to 50, 23 to 45, and particularly 25 to 40. If the mass ratio (Bi ₂ O ₃ + CuO) / ZnO is too small, the glass does not sufficiently soften and flow even when irradiated with laser light, and it becomes difficult to secure the laser sealing strength. On the other hand, if the mass ratio (Bi ₂ O ₃ + CuO) / ZnO is too large, the coefficient of thermal expansion tends to be high.

Al ₂ O ₃ is a component that enhances water resistance. Its content is preferably 0 to 5%, 0 to 3%, particularly 0.1 to 2%. If _{the content of Al 2} O ₃ is too large, the softening point becomes too high, and even if the glass is irradiated with laser light, it becomes difficult for the glass to soften.

CuO is a component that enhances the light absorption characteristics, that is, a component that absorbs laser light and softens the glass. Further, when _{the content of Bi 2} O ₃ is more than 77%, it is a component that suppresses devitrification during laser sealing. The content of CuO is preferably 4 to 15%, 5 to 12%, 6 to 11%, particularly more than 7 to 10%. If the content of CuO is too small, the light absorption characteristic becomes poor, and even if the glass is irradiated with laser light, the glass becomes difficult to soften. On the other hand, if the content of CuO is too large, the balance of the components in the glass composition is impaired, and conversely, the glass tends to be devitrified.

Fe ₂ O ₃ is a component that enhances the light absorption characteristic, that is, a component that absorbs laser light and softens the glass. Further, when _{the content of Bi 2} O ₃ is more than 77%, it is a component that suppresses devitrification during laser sealing. The content of Fe ₂ O ₃ is preferably 0 to 5%, 0.05 to 4%, 0.1 to 3%, and particularly 0.2 to 2%. If _{the content of Fe 2} O ₃ is too small, the light absorption characteristics are poor, and the glass is difficult to soften even when irradiated with laser light. On the other hand, if _{the content of Fe 2} O ₃ is too large, the component balance in the glass composition is impaired, and conversely, the glass tends to be devitrified.

MgO, CaO, SrO and BaO are components that enhance thermal stability. However, when _{the content of Bi 2} O ₃ + CuO is 83% or more and the total amount of MgO, CaO, SrO and BaO is too large, the coefficient of thermal expansion is lowered while ensuring fluidity at the time of laser sealing. It becomes difficult to make it. Therefore, the total amount and individual content of MgO, CaO, SrO and BaO are preferably 0 to 7%, 0 to 5%, 0 to 3%, less than 0 to 2.0%, 0 to 1%, 0 to 0. It is less than 1.0%, 0 to 0.5%, especially less than 0 to 0.1%.

The mass ratio (Bi ₂ O ₃ + CuO) / (MgO + CaO + SrO + BaO) is preferably 35 or more, 50 or more, 100 or more, and particularly 150 or more. If the mass ratio (Bi ₂ O ₃ + CuO) / (MgO + CaO + SrO + BaO) is too small, it becomes difficult to reduce the coefficient of thermal expansion while ensuring fluidity during laser sealing. In addition, "(Bi ₂ O ₃ + CuO) / (MgO + CaO + SrO + BaO)" _{refers to a value obtained by dividing the total amount of Bi 2} O ₃ and CuO by the total amount of MgO, CaO, SrO and BaO.

In addition to the above components, for example, the following components may be introduced. The total amount to be introduced is preferably 12% or less, 10% or less, and particularly preferably 5% or less.

SiO ₂ is a component that enhances water resistance. Its content is preferably 0 to 10%, 0 to 5%, and particularly preferably less than 0 to 1%. If _{the content of SiO 2} is too large, the softening point becomes too high, and it becomes difficult for the glass to soften even when irradiated with laser light.

Sb ₂ O ₃ is a component that suppresses devitrification. The content of Sb ₂ O ₃ is preferably 0 to 5%, 0 to 2%, and particularly 0 to 1%. Sb ₂ O ₃ is a component that suppresses devitrification during laser sealing when the content of _{Bi 2} O _{3 is more than 77%.} However, if _{the content of Sb 2} O ₃ is too large, the component balance in the glass composition is impaired, and conversely, the glass tends to be devitrified.

Nd ₂ O ₃ is a component that suppresses devitrification. The content of Nd ₂ O ₃ is preferably 0 to 5%, 0 to 2%, and particularly 0 to 1%. Nd ₂ O ₃ is a component that suppresses devitrification during laser sealing when the content of _{Bi 2} O _{3 is more than 77%.} However, if _{the content of Nd 2} O ₃ is too large, the component balance in the glass composition is impaired, and conversely, the glass tends to be devitrified.

Li ₂ O, Na ₂ O, K ₂ O and Cs ₂ O are components that lower the softening point, but have the effect of promoting devitrification during melting. Therefore, the total content of these components is preferably 2% or less, particularly preferably less than 1%.

P ₂ O ₅ is a component that suppresses devitrification during melting, but if the amount added is more than 1%, the glass tends to be phase-separated during melting.

La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ are components that suppress phase separation during melting, but if the content of each component is more than 3%, the softening point becomes too high, and the softening point becomes too high. Even if it is irradiated with laser light, the glass is hard to soften.

NiO, V ₂ O ₅ , CoO, MoO ₃ , TiO ₂ , CeO ₂ and MnO ₂ are components that enhance the light absorption characteristics. The content of each component is preferably less than 0-10%, particularly 0-7%. If the content of each component is too high, the glass tends to be devitrified during laser sealing.

The maximum particle size D _max of the glass powder is preferably 10 μm or less, particularly 5 μm or less. If the maximum particle size D _max of the glass powder is too large, the time required for laser sealing becomes long, it becomes difficult to make the gap between the objects to be sealed uniform, and the accuracy of laser sealing tends to decrease. Here, the "maximum particle size D _max " refers to a value measured by a laser diffractometer, and the cumulative amount is accumulated from the smallest particle in the volume-based cumulative particle size distribution curve measured by the laser diffractometer. The particle size is 99%.

In the glass powder of the present invention, the softening point is preferably 480 ° C. or lower, 450 ° C. or lower, and particularly preferably 350 to 430 ° C. If the softening point of the glass powder is too high, it becomes difficult for the glass to soften during laser sealing, so that the laser sealing strength cannot be increased unless the output of the laser beam is increased. Here, the "softening point" refers to the temperature of the fourth inflection point as measured by macro-type differential thermal analysis.

The sealing material of the present invention is a sealing material containing a glass powder and a fire-resistant filler powder, wherein the glass powder is the above-mentioned glass powder, the content of the glass powder is 50 to 95% by volume, and the fire-resistant filler is used. The powder content is preferably 5 to 50% by volume. The glass powder is a material that acts as a flux and softens and flows during laser sealing to airtightly integrate the objects to be sealed. The refractory filler powder is a material that acts as an aggregate to reduce the coefficient of thermal expansion of the sealing material and increase the mechanical strength of the sealing material layer.

In the sealing material of the present invention, the content of the refractory filler powder is preferably 1 to 50% by volume, 10 to 45% by volume, 20 to 40% by volume, and particularly 22 to 35% by volume. If the content of the refractory filler powder is too large, the content of the glass powder becomes relatively small, and it becomes difficult to secure the desired fluidity and laser sealing strength. If the content of the refractory filler powder is too small, the effect of adding the refractory filler powder becomes poor.

Various materials can be used as the fire-resistant filler powder. Among them, cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, β -Quartz solid solution and spojumen are preferable. These refractory filler powders have a low coefficient of thermal expansion, high mechanical strength, and good compatibility with the glass powder of the present invention.

The maximum particle size D _max of the refractory filler powder is preferably 15 μm or less, less than 10 μm, less than 5 μm, and particularly less than 0.5 to 3 μm. If the maximum particle size D _max of the refractory filler powder is too large, it becomes difficult to make the gap between the objects to be sealed uniform, and it becomes difficult to narrow the gap between the objects to be sealed, so that the airtight package can be made thinner and smaller. It becomes difficult. If the gap between the objects to be sealed is large and the difference in the coefficient of thermal expansion between the objects to be sealed and the material layer to be sealed is large, cracks or the like are likely to occur in the objects to be sealed or the material layer to be sealed.

The sealing material of the present invention may further contain a laser absorber in order to absorb the laser light and convert it into heat energy, and the content thereof is preferably 0 to 25% by volume, particularly 0 to 10. Volume%. If the content of the laser absorber is too large, the laser absorber tends to melt into the glass during laser sealing, and the thermal stability of the sealing material tends to be impaired.

The average particle size D ₅₀ of the laser absorber is preferably 0.01 to 3 μm, 0.1 to 2.5 μm, 0.3 to 2 μm, and particularly 0.5 to 1.5 μm. The maximum particle size D _max of the laser absorber is preferably less than 20 μm, less than 10 μm, 6 μm or less, and particularly 0.5 to 4 μm. If the particle size of the laser absorber is too small, the laser absorber tends to melt into the glass during laser sealing, and the thermal stability of the sealing material tends to be impaired. On the other hand, if the particle size of the laser absorber is too large, it becomes difficult to uniformly disperse the laser absorber in the sealing material, and there is a possibility that sealing failure may occur locally. Here, "average particle size D ₅₀ " refers to a value measured by a laser diffractometer, and the cumulative amount thereof is cumulative from the smallest particle in the volume-based cumulative particle size distribution curve measured by the laser diffractometer. The particle size is 50%.

Various materials can be used as the laser absorber, and among them, Cu-based oxides, Fe-based oxides, Cr-based oxides, and Mn-based oxides are used from the viewpoint of compatibility with the glass powder of the present invention. And these composite oxides are preferred. Among them, Cu-based oxides and this composite oxide are particularly preferable from the viewpoint of light absorption characteristics, and Mn-based oxides and this composite oxide are particularly preferable from the viewpoint of compatibility with the glass powder of the present invention.

The laser absorber is preferably black. When a black laser absorber is used, it becomes easy to convert the light energy of the laser beam into heat energy, and even if foreign matter is mixed in the sealing material, the appearance of the sealing material layer is less likely to be deteriorated. Examples of the black laser absorber include Al-Cu-Fe-Mn-based composite oxide, Al-Fe-Mn-based composite oxide, Co-Cr-Fe-based composite oxide, and Co-Cr-Fe-Mn-based composite oxidation. Material, Co-Cr-Fe-Ni-based composite oxide, Co-Cr-Fe-Mn-based composite oxide, Co-Cr-Fe-Ni-Zn-based composite oxide, Co-Fe-Mn-Ni-based composite oxidation things, Cr-Cu-based composite oxide, Cr-Cu-Mn-based composite oxide, Cr-Fe-Mn-based composite oxide, Fe-Mn-based composite _oxide, Cr _{2 O} 3, C are preferred, the present invention From the viewpoint of compatibility with glass powder, an Al-Fe-Mn-based composite oxide is particularly preferable.

In the sealing material of the present invention, the coefficient of thermal expansion is preferably 85 × 10 ^-7 / ° C or less, 82 × 10 ^-7 / ° C or less, 79 × 10 ^-7 / ° C or less, and particularly 50 × 10 ^-7 / ° C. It is above and 76 × 10 ^-7 / ° C. or less. In this way, when the object to be sealed has a low expansion, the stress remaining on the object to be sealed or the material layer for sealing becomes small, so that cracks are less likely to occur in the material layer to be sealed or the material to be sealed. Here, the "coefficient of thermal expansion" refers to a value measured by a push rod type coefficient of thermal expansion measurement (TMA) device, and the measurement temperature range is 30 to 300 ° C.

In the sealing material of the present invention, the softening point is preferably 510 ° C. or lower, 480 ° C. or lower, and particularly 350 to 450 ° C. If the softening point of the sealing material is too high, the sealing material layer becomes difficult to soften at the time of laser sealing, so that the laser sealing strength cannot be increased unless the output of the laser beam is increased.

The sealing material of the present invention may be used in a powder state, but it is easy to handle if it is uniformly kneaded with a vehicle and processed into a sealing material paste. The vehicle is mainly composed of a solvent and a resin. The resin is added for the purpose of adjusting the viscosity of the sealing material paste. Further, if necessary, a surfactant, a thickener and the like can be added. The sealing material paste is applied onto the object to be sealed using a coating machine such as a dispenser or a screen printing machine, and then subjected to a debindering step.

As the resin, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethylstyrene, polyethylene carbonate, methacrylic acid ester and the like can be used. In particular, acrylic acid ester and nitrocellulose are preferable because they have good thermal decomposability.

As solvents, N, N'-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyl lactone (γ-BL), tetraline, butyl carbitol acetate, ethyl acetate, isoamyl acetate, diethylene glycol monoethyl ether, diethylene glycol Monoethyl ether acetate, benzyl alcohol, toluene, 3-methoxy-3-methylbutanol, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene Glycol monobutyl ether, propylene carbonate, dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone and the like can be used.

Since the sealing material of the present invention has high fluidity at the time of laser sealing and has a low coefficient of thermal expansion, it can be suitably used for laser sealing of a package base of an airtight package and a glass lid. The airtight package according to the present invention is an airtight package in which a package base and a glass lid are airtightly sealed via a sealing material layer, and the sealing material layer is a sintered body of the sealing material, and the sealing is performed. The coating material is the above-mentioned sealing material. Hereinafter, the airtight package according to the present invention will be described in detail.

The package substrate preferably has a base portion and a frame portion provided on the base portion. By doing so, it becomes easy to accommodate an internal element such as a sensor element in the frame portion of the package substrate. The frame portion of the package base is preferably formed in a frame shape along the outer edge region of the package base. In this way, the effective area that functions as a device can be expanded. Further, it becomes easy to accommodate an internal element such as a sensor element in the space inside the package substrate, and it becomes easy to perform wiring joining and the like.

The surface roughness Ra of the surface of the region where the sealing material layer is arranged at the top of the frame portion is preferably less than 1.0 μm. When the surface roughness Ra of this surface becomes large, the accuracy of laser sealing tends to decrease. Here, the "surface roughness Ra" can be measured by, for example, a stylus type or non-contact type laser film thickness meter or a surface roughness meter.

The width of the top of the frame is preferably 100 to 7000 μm, 200 to 6000 μm, and particularly 300 to 5000 μm. If the width of the top of the frame is too narrow, it becomes difficult to align the sealing material layer with the top of the frame. On the other hand, if the top of the frame is too wide, the effective area that functions as a device becomes small.

The package substrate is preferably any one of glass ceramic, aluminum nitride, and aluminum oxide, or a composite material thereof (for example, one in which aluminum nitride and glass ceramic are integrated). Since glass-ceramic easily forms a reaction layer with a sealing material layer, a strong sealing strength can be ensured by laser sealing. Further, since the thermal via can be easily formed, the situation where the temperature of the airtight package rises excessively can be appropriately prevented. Since aluminum nitride and aluminum oxide have good heat dissipation, it is possible to appropriately prevent a situation in which the temperature of the airtight package rises excessively.

The glass ceramic, aluminum nitride, and aluminum oxide preferably have a black pigment dispersed (sintered in a state in which the black pigment is dispersed). In this way, the package substrate can absorb the laser light transmitted through the sealing material layer. As a result, the portion of the package substrate that comes into contact with the sealing material layer is heated during laser sealing, so that the formation of a reaction layer can be promoted at the interface between the sealing material layer and the package substrate.

The package substrate in which the black pigment is dispersed has a property of absorbing the laser light to be irradiated, for example, the total light transmittance at a thickness of 0.5 mm and the wavelength of the laser light to be irradiated (808 nm) is 10% or less. (Preferably 5% or less). In this way, the temperature of the sealing material layer tends to rise at the interface between the package substrate and the sealing material layer.

The thickness of the base of the package substrate is preferably 0.1 to 2.5 mm, particularly preferably 0.2 to 1.5 mm. As a result, the airtight package can be made thinner.

The height of the frame portion of the package substrate, that is, the height obtained by subtracting the thickness of the base portion from the package substrate is preferably 100 to 2500 μm, particularly 200 to 1500 μm. In this way, it becomes easy to reduce the thickness of the airtight package while properly accommodating the internal elements.

Various glasses can be used as the glass lid. For example, non-alkali glass, alkaline borosilicate glass, and soda-lime glass can be used. The glass lid may be laminated glass in which a plurality of glass plates are bonded together.

A functional film may be formed on the surface of the glass lid on the inner element side, or a functional film may be formed on the outer surface of the glass lid. In particular, an antireflection film is preferable as the functional film. As a result, the light reflected on the surface of the glass lid can be reduced.

The thickness of the glass lid is preferably 0.1 mm or more, 0.15 to 2.0 mm, and particularly 0.2 to 1.0 mm. If the thickness of the glass lid is small, the strength of the airtight package tends to decrease. On the other hand, if the glass lid is thick, it becomes difficult to reduce the thickness of the airtight package.

The sealing material layer softens and deforms by absorbing laser light to form a reaction layer on the surface layer of the package substrate, and has a function of airtightly integrating the package substrate and the glass lid.

The difference in thermal expansion coefficient between the glass lid and the sealing material layer is ^{preferably less than 50 × 10-7} / ° C. and less than 40 × ^10-7 / ° C., particularly preferably 30 × ^10-7 / ° C. or less. If the difference in the coefficient of thermal expansion is too large, the stress remaining in the sealed portion becomes unreasonably high, and the airtightness reliability of the airtight package tends to decrease.

The sealing material layer is preferably formed so that the contact position with the frame portion is separated from the inner edge of the top of the frame and is separated from the outer edge of the top of the frame. It is more preferably formed at a position separated from the inner edge of the top of the frame portion by 50 μm or more, 60 μm or more, 70 to 2000 μm, and particularly 80 to 1000 μm. If the distance between the inner edge of the top of the frame and the sealing material layer is too short, it will be difficult for the heat generated by local heating to escape during laser sealing, and the glass lid will be easily damaged during the cooling process. .. On the other hand, if the distance between the inner edge of the top of the frame and the sealing material layer is too long, it becomes difficult to miniaturize the airtight package. Further, it is preferably formed at a position separated from the outer edge of the top of the frame portion by 50 μm or more, 60 μm or more, 70 to 2000 μm, and particularly 80 to 1000 μm. If the distance between the outer edge of the top of the frame and the sealing material layer is too short, the heat generated by local heating during laser sealing is difficult to escape, and the glass lid is easily damaged during the cooling process. .. On the other hand, if the distance between the outer edge of the top of the frame and the sealing material layer is too long, it becomes difficult to miniaturize the airtight package.

The sealing material layer is preferably formed so that the contact position with the glass lid is 50 μm or more, 60 μm or more, 70 to 1500 μm, and particularly 80 to 800 μm away from the edge of the glass lid. If the distance between the edge of the glass lid and the sealing material layer is too short, the surface temperature difference between the surface on the inner element side and the surface of the outer surface of the glass lid in the edge region of the glass lid during laser sealing will increase. It becomes large and the glass lid is easily damaged.

The sealing material layer is preferably formed on the center line in the width direction of the top of the frame, that is, in the central region of the top of the frame. In this way, when the laser is sealed, the heat generated by the local heating can easily escape, so that the glass lid is less likely to be damaged. If the width of the top of the frame is sufficiently large, it is not necessary to form the sealing material layer on the center line in the width direction of the top of the frame.

The average thickness of the sealing material layer is preferably less than 8.0 μm, particularly 1.0 μm or more and less than 7.0 μm. The smaller the average thickness of the sealing material layer, the smaller the α-ray emission rate in the airtight package, so that it becomes easier to prevent soft errors in the internal element. The smaller the average thickness of the sealing material layer, the better the accuracy of laser sealing. Further, when the coefficient of thermal expansion of the sealing material layer and the glass lid are inconsistent, the stress remaining in the sealing portion after laser sealing can be reduced. Examples of the method for regulating the average thickness of the sealing material layer as described above include a method of applying a thin coating of the sealing material paste and a method of polishing the surface of the sealing material layer.

The maximum width of the sealing material layer is preferably 1 μm or more and 2000 μm or less, particularly 100 μm or more and 1500 μm or less. When the maximum width of the sealing material layer is narrowed, the sealing material layer can be easily separated from the edge of the frame portion, so that the stress remaining in the sealing portion after laser sealing can be easily reduced. Further, the width of the frame portion of the package substrate can be narrowed, and the effective area functioning as a device can be expanded. On the other hand, if the maximum width of the sealing material layer is too narrow, the sealing material layer is likely to be bulk fractured when a large shear stress is applied to the sealing material layer. Further, the accuracy of laser sealing tends to decrease.

Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view for explaining an embodiment of an airtight package according to the present invention. As can be seen from FIG. 1, the airtight package 1 includes a package base 10 and a glass lid 11. Further, the package base 10 has a base portion 12 and a frame-shaped frame portion 13 on the outer peripheral edge of the base portion 12. The internal element 14 is housed in the space surrounded by the frame portion 13 of the package base 10. An electric wiring (not shown) for electrically connecting the internal element 14 and the outside is formed in the package base 10.

The sealing material layer 15 is a sintered body of the sealing material, which contains glass powder and refractory filler powder, but substantially no laser absorber. The glass powder has a glass composition of Bi ₂ O ₃ + CuO 83 to 95%, Bi ₂ O ₃ 75 to 90%, B ₂ O ₃ 3 to 12%, ZnO 1 to 10%, Al. _It contains 2 O _{30 to} 5%, CuO 4 to 15%, Fe ₂ O _{30 to} 5%, MgO + CaO + SrO + BaO 0 to 7%, and substantially no PbO. Further, the sealing material layer 15 is arranged between the top of the frame portion 13 of the package base 10 and the surface of the glass lid 11 on the internal element 14 side over the entire circumference of the top of the frame portion 13. The width of the sealing material layer 15 is smaller than the width of the top of the frame portion 13 of the package base 10, and is further separated from the edge of the glass lid 11. Further, the average thickness of the sealing material layer 15 is less than 8.0 μm.

The airtight package 1 can be produced as follows. First, the glass lid 11 on which the sealing material layer 15 is formed in advance is placed on the package substrate 10 so that the sealing material layer 15 and the top of the frame portion 13 are in contact with each other. Subsequently, while pressing the glass lid 11 with a pressing jig, the laser light L emitted from the laser irradiation device is irradiated from the glass lid 11 side along the sealing material layer 15. As a result, the sealing material layer 15 softens and flows and reacts with the surface layer of the top of the frame portion 13 of the package base 10, so that the package base 10 and the glass lid 11 are airtightly integrated, and the airtight structure of the airtight package 1 is formed. Is formed.

The present invention will be described in detail based on examples. The following examples are merely examples. The present invention is not limited to the following examples.

Tables 1 and 2 show Examples (Samples Nos. 1 to 11) and Comparative Examples (Samples Nos. 12 to 15) of the present invention.

The glass powders listed in the table were prepared as follows. First, a glass batch containing raw materials such as various oxides and carbonates was prepared so as to have the glass composition shown in the table, and this was placed in a platinum crucible and melted at 1000 to 1100 ° C. for 1 to 2 hours. Next, the obtained molten glass was formed into flakes by a water-cooled roller. Finally, after pulverizing the flaky glass with a ball mill, _{glass powder having an average particle diameter D 50} of 1.0 μm and a maximum particle diameter D _max of 4 μm was obtained by air classification.

Cordierite, β-eucryptite and β-quartz solid solution were used as the refractory filler powder. These refractory filler powders are adjusted to an average particle size D of ₅₀ 1.0 μm and a maximum particle size of D _{max of 3 μm by air classification.}

An Al—Fe—Mn-based composite oxide was used as the laser absorber. _{The average particle size D 50} of the Al—Fe—Mn-based composite oxide was 1.0 μm, and the maximum particle size D _max was 2.5 μm.

The glass powder, the refractory filler powder, and the laser absorber were mixed at the mixing ratios shown in the table, and the sample No. 1 to 8 and 12 to 14 were prepared. Further, the glass powder and the refractory filler powder were mixed at the mixing ratio shown in the table, and the sample No. 9 to 11 and 15 were prepared. Sample No. The coefficient of thermal expansion, fluidity, laser sealing strength and airtightness were evaluated for 1 to 15.

The coefficient of thermal expansion is a value measured by a TMA device in a temperature range of 30 to 300 ° C. As the TMA measurement sample, each sample was densely sintered and then processed into a predetermined shape.

For fluidity, a powder having a mass corresponding to the synthetic density of each sample is dry-pressed in a button shape with an outer diameter of 20 mm using a mold, and this is placed on a high-strain point glass substrate having a thickness of 40 mm × 40 mm × 2.8 mm. Then, the temperature was raised in air at a rate of 10 ° C./min, the temperature was maintained at 510 ° C. for 10 minutes, the temperature was lowered to room temperature at 10 ° C./min, and the diameter of the obtained button was measured for evaluation. Specifically, the case where the flow diameter was 17.5 mm or more was evaluated as “◯”, and the case where the flow diameter was less than 17.5 mm was evaluated as “x”. The synthetic density is a theoretical density calculated by mixing the density of the glass powder and the density of the refractory filler powder by the volume ratio in the table.

A laser-sealed sealing structure (type A in the table) was prepared as follows. First, each sample and vehicle (tripropylene glycol monobutyl ether containing ethyl cellulose resin) are uniformly kneaded with a three-roll mill to form a paste, and then an alkali-free glass substrate (OA-10, 40 mm × manufactured by Nippon Electric Glass Co., Ltd.). On a 0.5 mm thickness, coefficient of thermal expansion of 38 × ^10-7 / ° C), apply in a frame shape (15 μm thickness, 0.6 mm width) along the edge of the non-alkali glass substrate, and in a drying oven at 120 ° C. It was dried for 10 minutes. Next, the temperature is raised from room temperature at 10 ° C./min, fired at 510 ° C. for 10 minutes, and then lowered to room temperature at 10 ° C./min to incinerate the resin components in the paste (debinder treatment) and to seal the sealing material. Fixing was performed to form a sealing material layer on a non-alkali glass substrate. Next, another non-alkali glass substrate (40 mm × 0.5 mm thick) on which the sealing material layer is not formed is accurately overlaid on the non-alkali glass substrate having the sealing material layer, and then the sealing material. By irradiating a laser beam having a wavelength of 808 nm from the non-alkali glass substrate side having the layer along the sealing material layer, the sealing material layer was softened and flowed, and the non-alkali glass substrates were air-sealed. The irradiation conditions (output, irradiation speed) of the laser beam were adjusted according to the average thickness of the sealing material layer. Finally, the obtained sealing structure was dropped onto concrete from 1 m above, and the one where peeling did not occur in the laser-sealed part was designated as "○", and the one where peeling occurred was designated as "x". The adhesive strength after laser sealing, that is, the laser sealing strength was evaluated.

Further, a laser-sealed sealing structure (type B in the table) was prepared as follows. First, each sample and vehicle (tripropylene glycol monobutyl ether containing ethyl cellulose resin) are uniformly kneaded with a three-roll mill to form a paste, and then an alkali-containing glass substrate (BDA manufactured by Nippon Electric Glass Co., Ltd., 10 mm × 0. 2 mm thick, coefficient of thermal expansion 66 × ^10-7 / ° C), applied in a frame shape (15 μm thickness, 0.3 mm width) along the edge of the alkali-containing glass substrate, and placed in a drying oven at 120 ° C. for 10 minutes. It was dry. Next, the temperature is raised from room temperature at 10 ° C./min, fired at 510 ° C. for 10 minutes, and then lowered to room temperature at 10 ° C./min to incinerate the resin components in the paste (debinder treatment) and to seal the sealing material. The fixing was performed to form a sealing material layer on the alkali-containing glass substrate. Next, the LTCC substrate (10 mm × 1.5 mm thickness, coefficient of thermal expansion 66 × 10 ^-7 / ° C.) is accurately overlaid on the alkali-containing glass substrate having the sealing material layer, and then the sealing material layer is formed. By irradiating the sealing material layer with laser light having a wavelength of 808 nm from the alkali-containing glass substrate side, the sealing material layer was softened and flowed, and the alkali-containing glass substrate and the LTCC substrate were air-sealed. The irradiation conditions (output, irradiation speed) of the laser beam were adjusted according to the average thickness of the sealing material layer. Finally, the obtained sealing structure was dropped onto concrete from 1 m above, and the one where peeling did not occur in the laser-sealed part was designated as "○", and the one where peeling occurred was designated as "x". The adhesive strength after laser sealing, that is, the laser sealing strength was evaluated.

The airtightness of the sealing structure (types A and B in the table) was evaluated as follows. A sealing structure was prepared for each sample in the same manner as in the evaluation of the laser sealing strength. However, unlike the evaluation of laser sealing strength, before laser sealing, a 300 nm thick metal Ca film (type A: □ 25 mm) is placed on a glass substrate corresponding to the central portion of the frame formed by the sealing material layer. , Type B: □ 5 mm, each) was formed by vacuum deposition. Next, the sealed structure after laser sealing was held for 24 hours in a constant temperature and humidity chamber maintained at 121 ° C., 100% humidity, and 2 atm. After that, the airtightness was evaluated by assigning "◯" to the metal Ca film having a metallic luster and "x" to indicate the transparent one. When the metal Ca film reacts with water, it becomes transparent calcium hydroxide.

As can be seen from Table 1, the sample No. In Nos. 1 to 11, since the glass composition of the glass powder was regulated within a predetermined range, the evaluation of fluidity, laser sealing strength and airtightness was good. On the other hand, sample No. Since Nos. 12 and 15 did not contain CuO in the glass powder, the evaluation of fluidity, laser sealing strength and airtightness was poor. Sample No. Since No. 13 does not contain ZnO in the glass powder, the evaluation of the laser sealing strength and the airtightness was poor in the type A sealing structure. Sample No. In No. 14, since _{the content of Bi 2} O ₃ + CuO in the glass powder was small, the evaluation of fluidity, laser sealing strength and airtightness was poor.

The glass powder of the present invention and the sealing material using the same include dye-sensitized solar cells, CIGS-based thin film compound solar cells, etc., in addition to laser sealing of organic EL devices such as organic EL displays and organic EL lighting devices. It is also suitable for laser sealing of solar cells, OLED packages, laser sealing of airtight packages such as LED packages, and the like.

1 Airtight package 10 Package base 11 Glass lid 12 Base 13 Frame 14 Internal element 15 Sealing material layer L Laser light

Claims (7)

As the glass composition, by mass%, Bi ₂ O ₃ + CuO 83 to 95%, Bi ₂ O ₃ 75 to 90%, B ₂ O ₃ 3 to 12%, ZnO 1 to less than 5 %, Al ₂ O _{3 to} 5 %, CuO 4 to 15%, Fe ₂ O _{30 to} 5%, MgO + CaO + SrO + BaO 0 to less than 0.1 %, and substantially no PbO. The glass powder according to claim 1, wherein the mass ratio (Bi ₂ O ₃ + CuO) / ZnO is 15 to 70. In sealing materials containing glass powder, refractory filler powder and laser absorbers
The glass powder is the glass powder according to claim 1 or 2 .
The content of the glass powder is 50 to 95% by volume,
A sealing material characterized in that the content of the refractory filler powder is 5 to 50% by volume. The refractory filler powder is one or more selected from cordierite, willemite, alumina, zirconium phosphate compound, zircon, zirconia, tin oxide, quartz glass, β-eucryptite, and spodium. The sealing material according to claim 3. The sealing material according to claim 3 or 4 , further comprising a laser absorber in an amount of 0 to 25% by volume. The fifth aspect of claim 5, wherein the laser absorber is one or more selected from Cu-based oxides, Fe-based oxides, Cr-based oxides, Mn-based oxides, and composite oxides thereof. Sealing material. The sealing material according to any one of claims 3 to 6 , wherein the sealing material is used for laser sealing.

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