KR102400344B1 - Package airframe and airtight package using it - Google Patents

Abstract

The package base of the present invention is characterized in that it has a substantially rectangular base, a substantially frame-like frame portion formed along an outer periphery of the base, and a stress buffer portion in all or a part of an inner wall corner of the frame portion.

Description

Package airframe and airtight package using it

The present invention relates to a package base and a hermetic package using the same, and more particularly, to a package base having a cavity for accommodating internal elements, and a hermetic package using the same.

The hermetic package generally includes a package base, a glass cover having light transmission properties, and internal elements accommodated therein.

Internal elements such as a sensor element mounted inside the hermetic package may be deteriorated by moisture entering from the surrounding environment. Conventionally, in order to integrate a package base and a glass cover, the organic resin adhesive which has low-temperature curability has been used. However, since the organic resin-based adhesive cannot completely shield moisture or gas, there is a risk of deterioration of internal elements over time.

On the other hand, when used for a sealing material containing glass powder and refractory filler powder, the sealing portion is less likely to be deteriorated by moisture in the surrounding environment, so that it is easy to secure the airtight reliability of the hermetic package.

However, since the glass powder has a higher softening temperature than the organic resin adhesive, there is a risk of thermal deterioration of the internal element during sealing. Due to these circumstances, laser sealing has recently been attracting attention. According to the laser sealing, it is possible to locally heat only the portion to be sealed, and the package body and the glass cover can be hermetically integrated without thermally deteriorating the internal elements.

Japanese Patent Laid-Open No. 2013-239609 Japanese Patent Laid-Open No. 2014-236202

By the way, the package body generally has a substantially rectangular base and a substantially frame-shaped frame part provided along the outer periphery of the said base. An internal element is accommodated in the internal space (cavity) formed by this base part and a frame part.

In recent years, the width of the frame portion has been narrowed due to progress in miniaturization of the hermetic package. When the width of the frame part is narrowed, the package body is easily deformed when the precursor of the package body is fired and sintered to obtain the package body. There is a fear that it will not be possible.

Therefore, the present invention has been made in view of the above circumstances, and its technical object is to create a package body that is hardly deformed or cracked even when the width of the frame portion is narrowed.

The present inventors discover that the said technical problem can be solved by forming a stress buffer part in the edge part of the inner wall of a cavity, and propose as this invention. That is, the package base of the present invention is characterized in that it has a substantially rectangular base, a substantially frame-like frame portion formed along the outer periphery of the base, and a stress buffer portion in all or a part of an edge portion of an inner wall of the frame portion.

The package base of the present invention has a substantially rectangular base and a substantially frame-like frame portion formed along the outer periphery of the base. In this way, it becomes easy to accommodate internal elements, such as a sensor element, in a cavity.

According to the investigation of the present inventors, after firing and sintering of the precursor of the package body, if a stress buffer is formed at the edge of the inner wall by paying attention to the fact that dents or cracks are likely to occur in the edge of the frame of the frame of the package body, the dents or cracks found to be more difficult to occur. Therefore, the package base of the present invention has a stress buffering portion at all or a part of the inner wall corners of the frame portion, that is, at least one of the four inner wall corners of the frame portion has a stress buffering portion at the inner wall corner portions.

Second, in the package base of the present invention, when viewed from the top of the frame portion, it is preferable that the stress buffer portion has an arc shape.

Third, in the package base of the present invention, when viewed from the top of the frame portion, it is preferable that the stress buffer portion is linear, and the angle between the stress buffer portion and the adjacent inner wall is 100° to 160°.

Fourth, in the package body of the present invention, when viewed from the top side of the frame portion, it is preferable that the outer wall corner of the frame portion is not chamfered. That is, it is preferable that the outer shape of the edge portion of the outer wall of the frame portion is substantially rectangular when viewed from the top portion side of the frame portion.

Fifth, in the package substrate of the present invention, it is preferable that the package substrate be any one of glass ceramic, aluminum nitride, and aluminum oxide, or a composite material thereof.

Hereinafter, the package base body of this invention is demonstrated, referring drawings. Fig. 1 (a) is a schematic perspective view for explaining an embodiment of a conventional package base body, and Fig. 1 (b) is an enlarged schematic perspective view of the main part X of an embodiment of a conventional package base body. As can be seen from FIG. The inner wall edge portion 4 of the frame portion 3 is formed so that the angle between the adjacent inner walls is 90°. The edge part 5 of the outer wall of the frame part 3 is formed so that the angle formed between adjacent outer walls may become 90 degrees. As can be seen from Fig. 1(b), due to the firing of the precursor of the package body 1 and shrinkage during sintering, stress in the direction of the arrow is generated, and the inner wall edge portion 4 of the frame portion 3 is A point of concentration of stress or strain occurs. And the crack 6 is generate|occur|produced from the edge part 4 of the inner wall of the frame part 3 by this concentration of stress and deformation|transformation amount.

Fig. 2(a) is a schematic diagram for explaining one embodiment of the package body of the present invention, and is a schematic view when viewed from the top side of the frame part, and Fig. 2(b) is a schematic diagram for explaining another embodiment of the package body of the present invention. It is a schematic diagram for doing so, and is a schematic diagram when it sees from the top part side of a frame part. As can be seen from FIG. 2A , the package base 10 has a substantially rectangular base 11 and a substantially frame-shaped frame portion 12 formed along the outer periphery of the base 11 . The inner wall edge portions 13 of the frame portion 12 all have the stress buffer portion 14 . The stress buffer portion 14 has an arc shape of 0.5 mm or more when viewed from the top of the frame portion 12 . This stress buffering portion 14 makes it difficult to concentrate stress or deformation on the inner wall edge portion 13 of the frame portion 12 . In addition, the outer wall edge part 15 of the frame part 12 is formed so that the angle which the outer walls make|form becomes 90 degrees when seen from the top part side of the frame part 12, and is not chamfered.

The package base 20 has the substantially rectangular base 21 and the substantially frame-shaped frame part 22 formed along the outer periphery of the base 21 so that FIG.2(b) may show. The inner wall edge portion 23 of the frame portion 22 has a stress buffer portion 24 . The stress buffer part 24 is connected to the inner wall adjacent to the stress buffer part 24 at an angle of 135 degrees when seen from the top side of the frame part 22. As shown in FIG. This stress buffering part 24 makes it difficult to concentrate stress or deformation on the edge part 23 of the inner wall of the frame part 22 . In addition, all of the outer wall edge portions 25 of the frame portion 22 are formed so that the angle between the outer walls is 90° when viewed from the top of the frame portion 22 , and are not chamfered.

Sixth, in the hermetic package of the present invention, in which the package base and the glass lid are hermetically sealed through a sealing material layer, it is preferable that the package base is the package base.

Seventh, in the hermetic package of the present invention, it is preferable that the average thickness of the sealing material layer is less than 8.0 µm. In this way, the precision of laser sealing can be increased.

Hereinafter, the hermetic package of the present invention will be described with reference to the drawings. It is a schematic sectional drawing for demonstrating one Embodiment of the hermetic package of this invention. The hermetic package 30 is equipped with the package base|substrate 31 and the glass cover 32 so that FIG. 3 may show. Further, the package body 31 has a substantially rectangular base 33 and a substantially frame-shaped frame portion 34 formed along the outer periphery of the base 33 . In addition, stress buffering portions (not shown) are formed at the corners of the inner wall at four places of the frame portion 34 .

The internal element 35 is accommodated in the frame part 34 of the package body 31 (in the space comprised by the frame part 34, the base 33, and the glass lid 32). In addition, an electric wiring (not shown) electrically connecting the internal element 35 and the outside is formed in the package body 31 .

The sealing material layer 36 is disposed over the entire perimeter of the top of the frame portion 34 between the top of the frame portion 34 of the package body 31 and the surface of the glass lid 32 on the inner element 35 side. has been Further, the sealing material layer 36 contains bismuth-based glass and refractory filler powder, but does not substantially contain a laser absorber. The width of the sealing material layer 36 is smaller than the width of the top of the frame portion 34 of the package body 31 , and is spaced apart from the edge of the glass lid 32 . In addition, the average thickness of the sealing material layer 36 is less than 8.0 mu m.

In addition, the hermetic package 30 can be produced as follows. First, the glass lid 32 on which the sealing material layer 36 is previously formed is placed on the package base 31 so that the sealing material layer 36 and the top of the frame portion 34 come into contact with each other. Then, the laser beam L emitted from the laser irradiation apparatus is irradiated along the sealing material layer 36 from the glass cover 32 side, pressing the glass cover 32 using a press jig|tool. As a result, the sealing material layer 36 softens and flows and reacts with the surface layer of the top portion of the frame portion 34 of the package body 31 so that the package body 31 and the glass lid 32 are hermetically integrated into the hermetic package ( 30) is formed.

Fig. 1 (a) is a schematic perspective view for explaining an embodiment of a conventional package base, and Fig. 1 (b) is an enlarged schematic perspective view of the main part X of an embodiment of a conventional package base.
Fig. 2(a) is a schematic diagram for explaining one embodiment of the package body of the present invention, and is a schematic diagram when viewed from the top side of the frame part, and Fig. 2(b) is a schematic diagram for explaining another embodiment of the package body of the present invention. It is a schematic diagram for doing so, and is a schematic diagram when it sees from the top part side of a frame part.
It is a schematic sectional drawing for demonstrating one Embodiment of the hermetic package of this invention.
Fig. 4 is a schematic diagram showing the softening point of the sealing material as measured by a macro-type DTA device.

The package base of the present invention has a substantially rectangular base and a substantially frame-like frame portion formed along the outer periphery of the base. In this way, it becomes easy to accommodate internal elements, such as a sensor element, in the frame part of a package body. Moreover, the effective area functioning as a device can be enlarged.

The package base of the present invention has a stress-absorbing portion on all or a part of the inner wall edge of the frame portion, and preferably has a stress-absorbing portion on all of the inner wall edge of the frame portion. In this way, after firing and sintering the precursor of the package base, deformation or cracks are less likely to occur in the package base.

It is preferable that the stress buffer part has an arc shape when seen from the top side of a frame part, and it is preferable that it is an arc shape with a radius of curvature of 0.5 mm or more, 1.0 mm or more, especially 1.5 mm or more. In this way, after firing and sintering the precursor of the package base, deformation or cracks are less likely to occur in the package base.

It is preferable that the stress buffer portion is linear when viewed from the top of the frame portion and is connected to the adjacent inner wall at an angle of 100° to 160°, in particular, an angle of 125 to 145°. In this way, after firing and sintering the precursor of the package base, deformation or cracks are less likely to occur in the package base.

It is preferable that the edge portion of the outer wall of the frame portion is not chamfered when viewed from the top side of the frame portion. In this way, the strength of the package body can be increased.

The width of the top of the frame portion is preferably 100 to 6000 μm, 500 to 4500 μm, particularly 1000 to 3000 μm. If the width of the top of the frame is too narrow, deformation or cracks are likely to occur when the precursor of the package base is fired and sintered. On the other hand, when the width of the top of the frame portion is too wide, the effective area functioning as a device becomes small. In addition, as the width of the top of the frame is narrower, dents or cracks are more likely to occur at the edge of the inner wall of the frame when the precursor of the package base is fired and sintered. get bigger

The height of the frame portion of the package base, that is, the height obtained by subtracting the thickness of the base from the package base, is preferably 200 to 4000 µm, particularly 500 to 3000 µm. In this way, it becomes easy to achieve thickness reduction of an airtight package, accommodating an internal element appropriately.

The thickness of the base of the package base is preferably 0.1 to 6.0 mm, particularly preferably 0.2 to 4.5 mm. Thereby, thickness reduction of an airtight package can be aimed at.

It is preferable that the surface roughness Ra of the top part of a frame part is less than 2.0 micrometers. When this surface roughness Ra becomes large, the precision of laser sealing will fall easily. Here, "surface roughness Ra" can be measured by, for example, a stylus type or non-contact type laser film thickness meter or surface roughness meter.

It is preferable that the package base is any one of glass ceramic, aluminum nitride, and aluminum oxide, or a composite material thereof (for example, one in which the base is made of aluminum nitride and the frame is made of glass ceramic and both are integrated). Since the glass ceramic can be manufactured by firing the green sheet laminate, the degree of freedom in shape is increased, and thus it is easy to form the stress buffer portion at the edge of the inner wall of the package body. Since aluminum nitride and aluminum oxide have good heat dissipation properties, it is possible to appropriately prevent a situation in which the temperature of the hermetic package excessively rises.

Glass ceramics, aluminum nitride, and aluminum oxide are preferably those in which a black pigment is dispersed (it is formed by firing and sintering in a state in which the black pigment is dispersed). In this way, the package base can absorb the laser light passing through the sealing material layer. As a result, since the portion in contact with the sealing material layer of the package body is heated during laser sealing, the formation of the reaction layer at the interface between the sealing material layer and the top of the frame portion of the package body can be promoted.

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

The hermetic package of the present invention is an hermetic package in which a sealing material layer is disposed between the top of the frame portion of the package body and the glass lid as described above, and the package body is the package body. Hereinafter, the hermetic package of this invention is demonstrated in detail.

The above embodiment is suitable for the package base, and description of overlapping portions is omitted here for convenience.

Various types of glass can be used as the glass cover. For example, alkali-free glass, alkali borosilicate glass, and soda-lime glass can be used. Moreover, the laminated glass which laminated|stacked the glass plate of several sheets may be sufficient as a glass cover.

A functional film may be formed on the surface of the inner element side of a glass lid, and a functional film may be formed in the surface of the outer side of a glass lid. In particular, an antireflection film is preferable as the functional film. Thereby, the light reflected by the surface of a glass cover can be reduced.

The thickness of the glass cover is preferably 0.1 mm or more, 0.15-2.0 mm, and particularly 0.2-1.0 mm. When the thickness of a glass cover is small, the intensity|strength of an airtight package will fall easily. On the other hand, when the thickness of a glass cover is large, it will become difficult to achieve thickness reduction of an airtight package.

The difference in the coefficient of thermal expansion between the glass cover and the sealing material layer is preferably less than 50×10 ^-7 /°C, less than 40×10 ^-7 /°C, and particularly preferably 30×10 ^-7 /°C or less. When this difference in thermal expansion coefficient is too large, the stress remaining in a sealing part will become high unreasonably, and it will become easy to fall the airtight reliability of an airtight package.

The sealing material layer is softened and deformed at the time of laser sealing, and has a function of forming a reaction layer on the surface layer of the package substrate to airtightly integrate the package substrate and the glass lid.

Preferably, the sealing material layer is formed so that the contact position with the frame is spaced apart from the inner edge of the top of the frame, and is spaced apart from the edge of the outer edge of the top of the frame, and 50 from the inner edge of the top of the frame. ㎛ or more, 60㎛ or more, 70 to 2000㎛, more preferably formed in a position spaced apart from 80 to 1000㎛. If the distance between the inner end edge of the top of the frame and the sealing material layer is too short, heat generated by local heating during laser sealing is difficult to be discharged, so that the glass cover is easily damaged in the cooling process. On the other hand, when the distance between the inner end edge of the top of the frame portion and the sealing material layer is too long, it becomes difficult to reduce the size of the hermetic package. Further, it is preferably formed at a position spaced apart from the outer edge 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, heat generated by local heating during laser sealing is difficult to be discharged, so that the glass cover is easily damaged during the cooling process. On the other hand, when the distance between the outer edge of the top of the frame and the sealing material layer is too long, it becomes difficult to reduce the size of the hermetic package.

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

It is preferable that the sealing material layer is formed on the center line in the width direction of the top of the frame portion, that is, it is formed in the central region of the top of the frame portion. In this way, since heat generated by local heating during laser sealing is easily discharged, the glass cover is less likely to be damaged. In addition, when the width of the top of the frame portion 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 portion.

The average thickness of the sealing material layer is preferably less than 8.0 mu m, in particular not less than 1.0 mu m, and less than 6.0 mu m. As the average thickness of the sealing material layer is smaller, the stress remaining in the sealing portion after laser sealing can be reduced when the thermal expansion coefficients of the sealing material layer and the glass lid are mismatched. In addition, it is also possible to increase the precision of laser sealing. In addition, as a method of regulating the average thickness of the sealing material layer as described above, a method of thinly coating a composite powder paste and a method of polishing the surface of the sealing material layer are exemplified.

The average width of the sealing material layer is preferably 1 µm or more, 2000 µm or less, 10 µm or more, 1000 µm or less, 50 µm or more, and 800 µm or less, particularly 100 µm or more, and 600 µm or less. When the average width of the sealing material layer is narrowed, the sealing material layer is easily separated from the edge of the frame portion, so that it is easy to reduce the stress remaining in the sealing portion after laser sealing. In addition, the width of the frame portion of the package body can be narrowed, and the effective area functioning as a device can be enlarged. On the other hand, if the average width of the sealing material layer is too narrow, bulk fracture of the sealing material layer is likely to be applied when a large shear stress is applied to the sealing material layer. In addition, the accuracy of laser sealing tends to decrease.

The surface roughness Ra of the sealing material layer is preferably less than 0.5 mu m, 0.2 mu m or less, particularly 0.01 to 0.15 mu m. Further, the surface roughness RMS of the sealing material layer is preferably less than 1.0 µm, 0.5 µm or less, particularly 0.05 to 0.3 µm. In this way, the adhesion between the package base and the sealing material layer is improved, and the precision of laser sealing is improved. Here, "surface roughness RMS" can be measured by, for example, a stylus type or non-contact type laser film thickness meter or a surface roughness meter. In addition, as a method of regulating the surface roughness Ra and RMS of the sealing material layer as described above, a method of polishing the surface of the sealing material layer and a method of reducing the particle size of the refractory filler powder are exemplified.

The sealing material layer is preferably formed of a sintered body of a composite powder including at least a glass powder and a refractory filler powder. The glass powder is a component that is softened and deformed during laser sealing to airtightly integrate the package body and the glass cover. The refractory filler powder acts as an aggregate and is a component that increases mechanical strength while lowering the thermal expansion coefficient of the sealing material. In addition to the glass powder and the refractory filler powder, the sealing material layer may contain a laser absorbing material in order to improve light absorption characteristics.

Various materials can be used as the composite powder. Among them, it is preferable to use a composite powder containing a bismuth-based glass powder and a refractory filler powder from the viewpoint of increasing the sealing strength. As the composite powder, it is preferable to use a composite powder containing 55 to 95% by volume of bismuth-based glass powder and 5 to 45% by volume of refractory filler powder, and 60 to 85% by volume of bismuth-based glass powder and 15 to 40% by volume. It is more preferred to use a composite powder containing . When the refractory filler powder is added, it becomes easy to match the thermal expansion coefficient of the sealing material layer to the thermal expansion coefficient of the glass lid and the package base. As a result, it is easy to prevent a situation in which unreasonable stress remains in the sealed portion after laser sealing. On the other hand, when the content of the refractory filler powder is too large, the content of the glass powder is relatively small, so that the surface smoothness of the sealing material layer is lowered, and the precision of laser sealing is easily lowered.

The softening point of the composite powder is preferably 510°C or less, 480°C or less, in particular 450°C or less. When the softening point of the composite powder is too high, it becomes difficult to increase the surface smoothness of the sealing material layer. The lower limit of the softening point of the composite powder is not particularly set, but considering the thermal stability of the glass powder, the softening point of the composite powder is preferably 350°C or higher. Here, a "softening point" is a 4th inflection point at the time of measuring with a macro-type DTA apparatus, and it corresponds to Ts in FIG.

The bismuth-based glass preferably contains 28 to 60% of Bi ₂ O ₃ , 15 to 37% of B ₂ O ₃ , and 1 to 30% of ZnO in mol% as a glass composition. The reason for limiting the content range of each component as mentioned above is demonstrated below. In addition, in description of a glass composition range, % indication points out mol%.

Bi ₂ O ₃ is a main component for lowering the softening point. The content of Bi ₂ O ₃ is preferably 28 to 60%, 33 to 55%, and particularly 35 to 45%. When there is too little content _of Bi2O3, a softening point becomes _high too much, and softening fluidity|liquidity will fall easily. _On the other hand, when there is too much content _of Bi2O3, it will become easy to devitrify glass at the time of laser sealing, and it originates in this devitrification and softening fluidity|liquidity will fall easily.

B ₂ O ₃ is an essential component as a glass-forming component. The content of B ₂ O ₃ is preferably 15 to 37%, 19 to 33%, particularly 22 to 30%. When there is too little content _{of B2O3} , since a glass network becomes difficult to form, it becomes easy to devitrify glass at the time of laser sealing. On the other hand, when there is too much content _{of B2O3} , the viscosity of glass will become high and softening fluidity will fall easily.

ZnO is a component which improves devitrification resistance. The content of ZnO is preferably 1 to 30%, 3 to 25%, 5 to 22%, particularly 5 to 20%. When content of ZnO becomes outside the said range, the component balance of a glass composition will crumble, and devitrification resistance will fall easily on the contrary.

In addition to the above components, for example, the following components may be added.

SiO2 is _a component which improves water resistance. The content of SiO ₂ is preferably 0 to 5%, 0 to 3%, 0 to 2%, and particularly 0 to 1%. When there is too much content _of SiO2, there exists a possibility that a softening point may rise unreasonably. In addition, the glass tends to be devitrified at the time of laser sealing.

Al ₂ O ₃ is a component that improves water resistance. The content of Al ₂ O ₃ is preferably 0 to 10%, 0.1 to 5%, and particularly preferably 0.5 to 3%. When there is too much content _{of Al2O3} , there exists a possibility that a softening point may rise unreasonably.

Li ₂ O, Na ₂ O, and K ₂ O are components that reduce devitrification resistance. Accordingly, the contents of Li ₂ O, Na ₂ O, and K ₂ O are preferably 0 to 5%, 0 to 3%, and particularly preferably less than 0 to 1%, respectively.

MgO, CaO, SrO, and BaO are components which increase devitrification resistance, but are components which raise a softening point. Therefore, the content of MgO, CaO, SrO, and BaO is preferably 0 to 20%, 0 to 10%, and particularly preferably 0 to 5%, respectively.

In order to lower the softening point of bismuth-based glass, it is necessary to introduce a large amount of Bi ₂ O ₃ into the glass composition, but if the content of Bi ₂ O ₃ is increased, the glass tends to devitrify during laser sealing, and due to this devitrification, softening fluidity It becomes easy to fall. In particular, when the content of Bi ₂ O ₃ is 30% or more, the tendency becomes remarkable. When CuO is added as this countermeasure, the fall _of devitrification resistance can be suppressed effectively even if content of Bi2O3 is ₃₀ % or more. In addition, the addition of CuO can enhance the laser absorption characteristics at the time of laser encapsulation. The content of CuO is preferably 0 to 40%, 1 to 40%, 5 to 35%, 10 to 30%, and particularly 13 to 25%. When there is too much content of CuO, the component balance of a glass composition will be impaired and devitrification resistance will fall easily on the contrary. In addition, the total light transmittance of the sealing material layer becomes too low, making it difficult to locally heat the boundary region between the package base and the sealing material layer.

Fe ₂ O ₃ is a component that improves devitrification resistance and laser absorption characteristics. The content of Fe ₂ O ₃ is preferably 0 to 10%, 0.1 to 5%, and particularly 0.4 to 2%. When there is too much content _of Fe2O3, the component balance of a glass composition will collapse, and devitrification resistance will fall easily _on the contrary.

MnO is a component that enhances laser absorption characteristics. The content of MnO is preferably 0 to 25%, particularly 5 to 15%. When there is too much content of MnO, devitrification resistance will fall easily.

_Sb2O3 is _a component which improves devitrification resistance. The content of Sb ₂ O ₃ is preferably 0 to 5%, particularly 0 to 2%. When there is too much content _{of Sb2O3} , the component balance of a glass composition will collapse, and devitrification resistance will fall easily on the contrary.

The average particle diameter D ₅₀ of the glass powder is preferably less than 15 µm, 0.5 to 10 µm, and particularly 1 to 5 µm. The softening point of a glass powder falls, so that average particle _diameter D50 of a glass powder is small. Here, "average particle _diameter D50" refers to the value measured on a volume basis by the laser diffraction method.

As the refractory filler powder, one or more selected from cordierite, zircon, tin oxide, niobium oxide, zirconium phosphate ceramics, willemite, β-eucliptite, and β-quartz solid solution is preferable, and in particular, β- Eucliptite or cordierite is preferred. These refractory filler powders have a high mechanical strength in addition to a low coefficient of thermal expansion, and have good compatibility with bismuth-based glass.

The average particle diameter D ₅₀ of the refractory filler powder is preferably less than 2 µm, particularly 0.1 µm or more, and less than 1.5 µm. If the average particle diameter D ₅₀ of the refractory filler powder is too large, the surface smoothness of the sealing material layer tends to decrease, and the average thickness of the sealing material layer tends to increase, and consequently, the laser sealing accuracy tends to decrease.

The 99% particle size D ₉₉ of the refractory filler powder is preferably less than 5 μm, 4 μm or less, particularly 0.3 μm or more, and 3 μm or less. If the 99% particle diameter D ₉₉ of the refractory filler powder is too large, the surface smoothness of the sealing material layer tends to decrease, and the average thickness of the sealing material layer tends to increase, and as a result, the accuracy of laser sealing tends to decrease. Here, "99% particle size D ₉₉ " refers to a value measured on a volume basis by laser diffraction method.

The sealing material layer may further contain a laser absorber in order to enhance light absorption characteristics, but the laser absorber has an action of promoting devitrification of the bismuth-based glass. Therefore, the content of the laser absorbing material in the sealing material layer is preferably 15% by volume or less, 10% by volume or less, 5% by volume or less, 1% by volume or less, 0.5% by volume or less, particularly substantially free (0.1% by volume). hereinafter) is preferred. When the devitrification resistance of the bismuth-based glass is good, the laser absorbing material may be introduced in an amount of 1% by volume or more, particularly 3% by volume or more, in order to improve the laser absorption characteristics. In addition, Cu-based oxides, Fe-based oxides, Cr-based oxides, Mn-based oxides, and spinel-type composite oxides thereof can be used as the laser absorber.

The thermal expansion coefficient of the sealing material layer is preferably 55×10 ^-7 to 95×10 ^-7 /°C, 60×10 ^-7 to 82×10 ^-7 /°C, particularly 65×10 ^-7 to 76×10 ^-7 /°C. In this way, the thermal expansion coefficient of the sealing material layer matches that of the glass cover or the package base, so that the sealing material layer is less likely to be bulk broken by shear stress. In addition, the "coefficient of thermal expansion" is the value measured with the TMA (press-bar type|mold coefficient of thermal expansion measurement) apparatus in the temperature range of 30-300 degreeC.

Although the sealing material layer can be formed by various methods, it is preferable to form it by application|coating and sintering of a composite powder paste among them. And it is preferable to use an applicator such as a dispenser or a screen printing machine for application of the composite powder paste. In this way, the dimensional accuracy of the sealing material layer (the dimensional accuracy of the width of the sealing material layer) can be increased. Here, the composite powder paste is a mixture of the composite powder and vehicle. And the vehicle usually includes a solvent and a resin. The resin is added for the purpose of adjusting the viscosity of the paste. In addition, if necessary, a surfactant, a thickener, and the like may be added.

The composite powder paste is usually produced by kneading the composite powder and the vehicle by means of three rollers or the like. A vehicle usually contains a resin and a solvent. As the resin used for the vehicle, acrylic acid ester (acrylic resin), ethyl cellulose, polyethylene glycol derivative, nitrocellulose, polymethyl styrene, polyethylene carbonate, polypropylene carbonate, methacrylic acid ester, etc. can be used. As a solvent used in the vehicle, N,N'-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyllactone (γ-BL), tetralin, butylcarbitol acetate, ethyl acetate, acetic acid Isoamyl, 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 mono Methyl 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.

The composite powder paste may be applied on the top of the frame portion of the package body, but is preferably applied in a frame shape along the outer peripheral edge region of the glass lid. In this way, baking of the sealing material layer with the package base becomes unnecessary, and thermal deterioration of internal elements such as deep ultraviolet LED elements can be suppressed.

As a method for manufacturing the hermetic package of the present invention, it is preferable to hermetically seal the package base and the glass lid by irradiating laser light from the glass lid side toward the sealing material layer and softening and deforming the sealing material layer to obtain an airtight package. In this case, although the glass lid may be disposed below the package base, it is preferable to arrange the glass lid above the package base from the viewpoint of laser sealing efficiency.

Various lasers can be used as the laser. In particular, a semiconductor laser, a YAG laser, _a CO2 laser, an excimer laser, and an infrared laser are preferable at the point of handling.

The atmosphere in which laser sealing is performed is not specifically limited, An atmospheric atmosphere may be sufficient, and an inert atmosphere, such as a nitrogen atmosphere, may be sufficient.

It is preferable to perform laser sealing in the state which pressed the glass cover. Thereby, the intensity|strength of laser sealing can be raised.

Example

Hereinafter, the present invention will be described in detail based on Examples. In addition, the following examples are mere examples. The present invention is not limited in any way to the following examples.

Initially, various oxides and carbonates to contain 39% of Bi ₂ O ₃ , 23.7% of B ₂ O ₃ , 14.1% of ZnO, 2.7% of Al ₂ O ₃ , 20% of CuO, and 0.6% of Fe ₂ O ₃ in mol% as a glass composition. The glass batch which combined raw materials, such as these, was prepared, this was put into a platinum crucible, and it melted at 1200 degreeC for 2 hours. Next, the obtained molten glass was shape|molded into flake shape with the water-cooling roller. Finally, the flaky bismuth-based glass was pulverized with a ball mill and air-classified to obtain a bismuth-based glass powder.

Furthermore, 90.0 mass % of bismuth-type glass powder and 10.0 mass % of refractory filler powder were mixed in the ratio, and the composite powder was produced. Here, the average particle diameter D ₅₀ of the bismuth-based glass powder was 1.0 μm, and the 99% particle diameter D ₉₉ was 2.5 μm, the average particle diameter D ₅₀ of the refractory filler powder was 1.0 μm, and the 99% particle diameter D ₉₉ was 2.5 μm. Also, the refractory filler powder is β-eucliptite.

As a result of measuring the coefficient of thermal expansion of the obtained composite powder, the coefficient of thermal expansion was 71 × 10 ^-7 /°C. In addition, the thermal expansion coefficient is measured with a press-bar type TMA apparatus, and the measurement temperature range is 30-300 degreeC.

Further, along the outer periphery of a glass cover made of borosilicate glass (BDA manufactured by Nippon Electric Glass Co., Ltd., 30 mm × 20 mm × thickness 0.2 mm), the composite powder was used to form a frame-like sealing material layer. . In detail, first, the composite powder, vehicle, and solvent are kneaded so that the viscosity is about 100 Pa·s (25°C, Shear rate: 4), and then kneaded with a 3 roll mill until the powder is uniformly dispersed. It was paste-formed, and the composite powder paste was obtained. As the vehicle, an ethyl cellulose resin dissolved in a glycol ether-based solvent was used. Then, along the outer peripheral edge of the glass lid, the composite powder paste was printed in the form of a frame by a screen printing machine. Further, a sealing material layer having an average width of 400 µm and an average thickness of 6 µm was formed on the glass cover by drying at 120° C. for 10 minutes in an atmospheric atmosphere and then baking at 500° C. for 10 minutes in an atmospheric atmosphere.

Next, a package base having a substantially rectangular base and a substantially frame-shaped frame portion formed along the outer periphery of the base was produced. In detail, a green sheet (MLB manufactured by Nippon Electric Glass Co., Ltd.) is obtained to obtain a package base having dimensions of 30 mm × 20 mm in outer shape, 2.5 mm in width of the frame, 2.5 mm in height of the frame, and 1.0 mm in thickness of the base. -26B) was laminated and pressed, and then fired at 870° C. for 20 minutes to obtain a package base made of glass ceramic. Here, a stress buffer portion having a curvature radius of 2 mm is formed in all of the corner portions of the inner wall of the frame portion in a plan view, and no dents or cracks were observed in the stress buffer portion. In addition, the surface roughness Ra of the top part of the frame part of a package base|substrate was 0.2 micrometer.

Finally, the package base and the glass lid were laminated with the sealing material layer interposed therebetween. Then, while pressing the glass cover using a pressing jig, a semiconductor laser having a wavelength of 808 nm, an output of 4 W, and an irradiation diameter of φ 0.5 mm is irradiated from the glass cover side toward the sealing material layer at an irradiation rate of 15 mm/sec, and the sealing material layer is irradiated with By softening and deforming, the package base and the glass cover were hermetically integrated to obtain an hermetic package.

Cracks and hermetic reliability were evaluated for the obtained hermetic package. First, as a result of observing the sealing portion and the edge portion of the inner wall of the package body with an optical microscope, the occurrence of cracks was not confirmed. Then, after performing a high-temperature, high-humidity and high-pressure test: HAST test (Highly Accelerated Temperature and Humidity Stress test) on the obtained airtight package, the vicinity of the sealing material layer was observed. As a result, deterioration, cracks, peeling, etc. were not confirmed at all. In addition, the conditions of a HAST test are 121 degreeC, 100% of humidity, 2 atm, and 24 hours.

(industrial applicability)

The package base of the present invention can be suitably applied to an airtight package in which internal elements such as a sensor element are mounted, but in addition to that, a deep ultraviolet LED element, a piezoelectric vibration element, a wavelength conversion element in which quantum dots are dispersed in a resin, etc. It can be suitably applied to packages, etc.

1, 10, 20, 31: package gas 2, 11, 21, 33: donation
3, 12, 22, 34: frame portion 4, 13, 23: inner wall corner portion
5, 15, 25: outer wall edge part 6: crack
14, 24: stress buffer 30: airtight package
32: glass cover 35: internal element
36: sealing material layer L: laser beam

Claims (7)

A package body comprising: a rectangular base; a frame part formed along the outer periphery of the base part;
A sealing material layer comprising at least a glass powder and a sintered body of a composite powder comprising a refractory filler powder having an average particle diameter D ₅₀ of less than 2 μm is provided between the top of the frame portion of the package body and the glass lid. The method of claim 1,
An airtight package characterized in that the stress buffer portion has an arc shape when viewed from the top of the frame portion. The method of claim 1,
An airtight package, characterized in that the stress buffer portion is linear when viewed from the top of the frame portion, and the angle between the stress buffer portion and the adjacent inner wall is 100° to 160°. 4. The method according to any one of claims 1 to 3,
An airtight package characterized in that the edge portion of the outer wall of the frame portion is not chamfered when viewed from the top side of the frame portion. 4. The method according to any one of claims 1 to 3,
Airtight package, characterized in that the package base is any one of glass ceramic, aluminum nitride, aluminum oxide, or a composite material thereof. delete 6. The method of claim 5,
An airtight package, characterized in that the average thickness of the sealing material layer is less than 8.0 μm.

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