JP5920513B2 - Lead-free glass for sealing, sealing material, sealing material paste - Google Patents

Description

  The present invention relates to a lead-free glass for sealing, a sealing material and a sealing material paste, and in particular, a lead-free glass for sealing made of vanadium-based glass having a low softening point and improved water resistance, and a sealing material using the same And a sealing material paste.

  Resin and low-melting glass are used as sealing materials for sealing parts of electronic products and electrical products such as display panels and semiconductor packages, but low-melting glass has the advantage of higher airtightness than resin. Because it is, it has come to be used a lot. As such a low-melting glass, glass containing lead oxide as a main component has been conventionally used (see Patent Document 1).

  However, in recent years, the harmfulness of lead compounds to the human body and the environment has been regarded as a problem, and development of materials that do not contain lead oxide is desired in sealing glass, and various materials have been studied. .

  As a low-melting glass not containing lead oxide, a softening point is lower than that of lead-based sealing glass. Therefore, vanadium-based glass that can be applied at a low temperature has been proposed, and its practical application has been studied (for example, patent documents) 2). A vanadium-based glass having a further lowered softening point (Ts) and improved water resistance has also been proposed (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 2-48430 JP 2009-2221048 A JP 2010-52990 A

  However, even the vanadium-based low-melting glass as described in Patent Documents 2 and 3 is still insufficient in water resistance, and further improvement in characteristics has been a challenge when put to practical use. Further, a lead-free glass for sealing that has a lower softening point (Ts) and can be used in a low temperature range is demanded.

  Accordingly, in order to solve the above-described problems, the present invention aims to provide a novel lead-free glass for sealing that can be used in a low temperature range and has improved water resistance.

In order to solve the above problems, the present inventors have intensively studied, and as a result, found that a vanadium glass having a specific composition has a low melting point sufficient for use as a sealing application and is excellent in water resistance. It was. That is, the lead-free glass for sealing of the present invention has 10 to 55% by mass of V ₂ O ₅ , 1 to 10% by mass of P ₂ O ₅ , 32.5 to 54.5% by mass of TeO ₂ , 0 ~ 13 mass% ZnO, 0-13 mass% BaO, and 1-6 mass% CuO, ZnO and BaO are in the range of 0-13 mass% in total ZnO + BaO, It is characterized by not containing PbO and Fe ₂ O ₃ substantially.

  According to the lead-free glass for sealing, sealing material and sealing material paste of the present invention, the glass material itself has a low melting point and can be sealed at a low temperature, so that it can be safely sealed and handled easily. Since the heating temperature during the sealing operation can be sufficiently secured, the sealing operation can be performed stably.

  Moreover, since the lead-free glass for sealing, sealing material, and sealing material paste of this invention are excellent in water resistance, generation | occurrence | production of the malfunction at the time of product manufacture is suppressed, and also aged deterioration of a product is suppressed. Therefore, the electronic product and the electrical product sealed by these have high reliability and can have a long life.

It is sectional drawing which shows the structure of the semiconductor device by embodiment of this invention. It is sectional drawing which shows the manufacturing process of the semiconductor device by embodiment of this invention.

The lead-free glass for sealing of the present invention is vanadium-based glass containing V ₂ O ₅ , P ₂ O ₅ , and TeO ₂ as essential components as described above. Hereinafter, the components of the lead-free glass for sealing will be described in detail.

V ₂ O ₅ used in the present invention is a component that functions as a network former in the glass, further lowers the softening point of the glass, and imparts fluidity to the glass during melting. This V ₂ O ₅ is contained in the glass in the range of 10 to 55% by mass, and preferably 20 to 45% by mass. If V ₂ O ₅ is less than 10% by mass, the softening point becomes high, and if it exceeds 55% by mass, the glass tends to crystallize.

P ₂ O ₅ used in the present invention is a component having a function as a network former in glass. This P ₂ O ₅ is contained in the glass in the range of 1 to 10% by mass, and preferably 1.5 to 9% by mass. If P ₂ O ₅ is less than 1% by mass, the function as a network former is not exhibited and vitrification becomes difficult, and if it exceeds 10% by mass, the softening point becomes high or the water resistance decreases. .

TeO ₂ used in the present invention is a component that improves the water resistance of glass. This TeO ₂ is contained in the range of 15 to 70% by mass in the glass, and is preferably 30 to 60% by mass. If TeO ₂ is less than 15% by mass, the effect of improving the water resistance is not exhibited effectively, and if it exceeds 70% by mass, the thermal expansion coefficient increases.

  ZnO used in the present invention is an arbitrary component that suppresses the devitrification of the glass and lowers the softening point and the thermal expansion coefficient of the glass. This ZnO is contained in the glass in the range of 0 to 13% by mass. When ZnO exceeds 13% by mass, the thermal expansion coefficient of the lead-free glass for sealing increases, cracks and microcracks occur in the interface between the sealed object and the sealing material and in the sealing material, and a hermetic seal is obtained. There is a risk of not.

  BaO used in the present invention is an arbitrary component that suppresses devitrification of the glass and lowers the viscosity of the glass. This BaO is contained in the glass in the range of 0 to 13% by mass. If BaO exceeds 13% by mass, the softening point becomes high, and sealing at low temperatures becomes difficult. In addition, an increase in the thermal expansion coefficient of the lead-free glass for sealing may cause cracks or microcracks in the interface between the material to be sealed and the sealing material or in the sealing material, and there is a possibility that airtight sealing cannot be obtained. .

  Moreover, ZnO and BaO which are optional components are contained in a range of 0 to 13% by mass of these total amounts ZnO + BaO in the glass. When this total amount exceeds 13% by mass, the thermal expansion coefficient of the lead-free glass for sealing increases, cracks and microcracks are generated in the interface between the sealed object and the sealing material and in the sealing material, and the hermetic sealing is achieved. May not be obtained.

Other components include CuO, MgO, CaO, SrO and the like, and can be contained within a range that does not impair the effects of the present invention. In particular, CuO is a component that improves chemical durability, and is preferably contained in an amount of 1 to 6% by mass.
Moreover, the desired average thermal expansion coefficient of the lead-free glass for sealing is 140 × 10 ⁻⁷ / ° C. or less. If it exceeds 140 × 10 ⁻⁷ / ° C., it is difficult to sufficiently reduce the average thermal expansion coefficient as a sealing material even if an inorganic filler is added. Moreover, the fluidity at the time of sealing the sealing material may be reduced. Preferably, it is 125 × 10 ⁻⁷ / ° C. or less, and more preferably 115 × 10 ⁻⁷ / ° C. or less. The lower limit value of the average thermal expansion coefficient is not particularly limited, but if it is intentionally limited, it is preferably 80 × 10 ⁻⁷ / ° C. or higher, more preferably 90 × 10 ⁻⁷ / ° C. or higher.

Further, sealing lead-free glass of the present invention is substantially free of PbO and Fe ₂ O _3. PbO is a component that has a heavy load on the environment and the human body and is not preferable for use in the product itself. Further, Fe ₂ O ₃ is, the firing temperature during sealing to increase the softening point (Ts) is increased, not to exhibit the effect of the present invention with the inclusion of this. Here, “substantially not contained” means that the amount contained in the glass is 0.1% by mass or less.

  By setting it as the above mixing | blending, the lead-free glass for sealing excellent in water resistance with a low melting point is obtained. Here, the low melting point in the present invention means that the lead-free glass for sealing has a softening point of 375 ° C. or lower, preferably 365 ° C. or lower, particularly preferably 355 ° C. or lower. When the softening point is low, the temperature at the time of sealing can be lowered, so that the sealing process can be performed in a low temperature range, the thermal influence on the workpiece can be reduced, and the heat energy consumption can be reduced. Further, since the work can be performed at a low temperature, the sealing operation can be performed safely and reliably.

  Further, the water resistance is evaluated by a mass reduction amount when the lead-free glass for sealing is immersed in ion exchange water at 45 ° C. for 72 hours, and the mass reduction amount is preferably 1.0% or less, preferably 0.5% It is more preferable that it is below, and it is especially preferable that it is 0.3% or less. When this water resistance is lowered, the glass component comes out due to contact with moisture and the amount of mass reduction increases, and the glass may be altered to impair the function as a sealing material. In such a case, it is conceivable that the product deteriorates with time and has a short life. In addition, the electrical conductivity of the ion exchange water used here is 1-2 μS / cm.

  Crystallization is determined by whether or not a crystallization peak appears when measurement is performed in the range of 25 ° C. (room temperature) to 500 ° C. with a differential thermal analyzer (TG-8110, manufactured by Rigaku Corporation).

  Next, in the sealing material of the present invention, the raw material powder mixture is placed in a container such as a platinum crucible so as to have the above blending ratio, and this is heated and melted in a heating furnace such as an electric furnace for a predetermined time. It is possible to vitrify, shape this melt into a sheet with a water-cooled roller, and pulverize it to an appropriate particle size with a pulverizer to obtain a lead-free glass for sealing. The particle size of the lead-free glass for sealing is preferably in the range of 0.05 to 100 μm, and the coarse particles by the pulverization may be classified and removed. However, in the lead-free glass for sealing used as a sealing material for ultra-thin display panels for small devices, it is recommended that the particle size is 10 μm or less, more preferably 6 μm or less.

  For the above pulverization, various dry pulverizers such as a ball mill conventionally used for the production of glass powder can be used. In particular, wet pulverization is preferably used for a fine particle size of 3 μm or less. This wet pulverization is pulverized in an aqueous solvent such as water or an aqueous alcohol solution using pulverization media (balls or beads) made of alumina or zirconia having a diameter of 5 mm or less, and is pulverized more finely than dry pulverization. However, since it is fine pulverization using an aqueous solvent, the glass composition as the pulverized product needs to have high water resistance.

  The sealing material of the present invention can be composed of only the lead-free glass for sealing obtained as described above. It is composed of an inorganic filler such as an expansion filler. The blending amount of the inorganic filler is appropriately set according to the purpose, but is preferably 40% by volume or less with respect to the sealing material. If the blending amount of the inorganic filler exceeds 40% by volume, the fluidity of the sealing material at the time of sealing may be reduced, and the adhesive strength may be reduced. The sealing material contains lead-free glass for sealing and 0 to 40% by volume of an inorganic filler. The lower limit value of the content of the inorganic filler is not particularly limited.

  A typical example of the inorganic filler is a low expansion filler. A low expansion filler has a lower thermal expansion coefficient than a lead-free glass for sealing. The sealing material may contain an inorganic filler other than the low expansion filler. As described above, the content of the low expansion filler is preferably 40% by volume or less. The lower limit of the content of the low expansion filler is not particularly limited, and is appropriately set according to the difference in thermal expansion coefficient between the lead-free glass for sealing and the semiconductor substrate for elements or the substrate for sealing. However, in order to obtain a practical blending effect (adjustment of the thermal expansion coefficient of the sealing material and improvement of the sealing strength), it is preferable to blend 5% by volume or more.

The low expansion filler is at least one selected from silica, alumina, zirconia, zirconium silicate, aluminum titanate, mullite, cordierite, eucryptite, spodumene, zirconium phosphate compound, tin oxide compound, and quartz solid solution. It is preferable to use seeds. Examples of the zirconium phosphate-based compound include (ZrO) ₂ P ₂ O ₇ , NaZr ₂ (PO ₄ ) ₃ , KZr ₂ (PO ₄ ) ₃ , Ca _0.5 Zr ₂ (PO ₄ ) ₃ , and NbZr (PO ₄ ). ₃ , Zr ₂ (WO ₃ ) (PO ₄ ) ₂ , and composite compounds thereof.

  The sealing material paste of this embodiment consists of a mixture of a sealing material and a vehicle. As the vehicle, for example, a binder component such as methyl cellulose, ethyl cellulose, carboxymethyl cellulose, oxyethyl cellulose, benzyl cellulose, propyl cellulose, nitrocellulose or the like dissolved in a solvent such as terpineol, butyl carbitol acetate, ethyl carbitol acetate, or methyl Acrylic resins (binder components) such as (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl methacrylate, methyl ethyl ketone, terpineol, butyl carbitol acetate, ethyl carbitol acetate, etc. Those dissolved in a solvent are used.

  The mixing ratio of the sealing material and the vehicle is appropriately set according to the desired paste viscosity and the like, and is not particularly limited. The viscosity of the sealing material paste may be adjusted to the viscosity corresponding to the device applied to the sealing substrate or the device semiconductor substrate, the mixing ratio of the organic resin (binder component) and the solvent, and the sealing material and the vehicle. The mixing ratio can be adjusted. The sealing material paste may contain a known additive in a glass paste like an antifoaming agent or a dispersing agent. A known method using a rotary mixer equipped with a stirring blade, a roll mill or the like can be applied to the preparation of the sealing material paste.

  The above-mentioned lead-free glass for sealing, sealing material, and sealing material paste are used in a sealing process for a semiconductor device or the like (for example, a bonding process between a semiconductor substrate for elements and a sealing substrate). FIG. 1 shows a configuration example of a semiconductor device using the lead-free glass for sealing, the sealing material, and the sealing material paste of this embodiment. Examples of the semiconductor device 1 shown in FIG. 1 include, but are not limited to, a pressure sensor, an acceleration sensor, a gyro sensor, a micromirror, an optical device using a CCD element or a CMOS element, and the like.

  The semiconductor device 1 includes an element semiconductor substrate 2 and a sealing substrate 3. Various semiconductor substrates typified by Si substrates are applied to the element semiconductor substrate 2. As the sealing substrate 3, a semiconductor substrate (Si substrate or the like), a glass substrate, a ceramic substrate, or the like is used. An element portion 4 corresponding to the semiconductor device 1 is provided on the surface 2 a of the element semiconductor substrate 2. The element unit 4 includes a sensor element, a mirror element, a light modulation element, a light detection element, and the like, and has various known structures. The semiconductor device 1 is not limited to the structure of the element unit 4.

  A first sealing region 5 is provided along the outer periphery of the element portion 4 on the surface 2 a of the element semiconductor substrate 2. The first sealing region 5 is provided so as to surround the element portion 4. A second sealing region 6 corresponding to the first sealing region 5 is provided on the surface 3 a of the sealing substrate 3. The element semiconductor substrate 2 and the sealing substrate 3 are formed in a predetermined manner so that the surface 2a having the element portion 4 and the first sealing region 5 and the surface 3a having the second sealing region 6 face each other. It is arranged with a gap. A gap between the element semiconductor substrate 2 and the sealing substrate 3 is sealed with a sealing layer 7.

  The sealing layer 7 is formed between the sealing region 5 of the element semiconductor substrate 2 and the sealing region 6 of the sealing substrate 3 so as to seal the element portion 4. The element portion 4 is hermetically sealed with a package including the element semiconductor substrate 2, the sealing substrate 3, and the sealing layer 7. The sealing layer 7 is composed of a melt-fixed layer of the sealing material of this embodiment. The package is hermetically sealed in a state corresponding to the semiconductor device 1. For example, when the semiconductor device 1 is a MEMS, the package is generally hermetically sealed in a vacuum state.

  Next, the manufacturing process of the semiconductor device 1 of this embodiment will be described with reference to FIG. First, as shown in FIG. 2A, a sealing material layer (firing layer of sealing material) 8 is formed in the sealing region 6 of the sealing substrate 3. In forming the sealing material layer 8, first, a sealing material paste is applied to the sealing region 6 and dried to form an application layer of the sealing material paste. The specific configuration of the sealing material and the sealing material paste is as described above.

  The sealing material paste is applied onto the sealing region 6 by applying a printing method such as screen printing or gravure printing, or is applied along the sealing region 6 using a dispenser or the like. The coating layer of the sealing material paste is dried, for example, at a temperature of 120 ° C. or more for 10 minutes or more. A drying process is implemented in order to remove the solvent in an application layer. If the solvent remains in the coating layer, the binder component may not be sufficiently removed in the subsequent firing step.

  The sealing material layer 8 is formed by baking the coating layer of the sealing material paste described above. In the firing step, first, the coating layer is heated to a temperature below the glass transition point of the sealing lead-free glass that is the main component of the sealing material, and after removing the binder component in the coating layer, the softening point of the sealing lead-free glass or higher. The lead-free glass for sealing is melted and baked on the sealing substrate 3. In this way, the sealing material layer 8 composed of the fired layer of the sealing material is formed.

  Next, as shown in FIG. 2B, a sealing substrate 3 having a sealing material layer 8 and an element semiconductor substrate 2 having an element portion 4 produced separately from the surface 2a and the surface 3a. Are laminated via the sealing material layer 8 so as to face each other. A gap is formed on the element portion 4 of the element semiconductor substrate 2 based on the thickness of the sealing material layer 8. Thereafter, the laminate of the sealing substrate 3 and the element semiconductor substrate 2 is heated to a temperature equal to or higher than the softening point of the lead-free glass for sealing in the sealing material layer 8 to melt and solidify the lead-free glass for sealing. Thus, the sealing layer 7 for hermetically sealing the gap between the element semiconductor substrate 2 and the sealing substrate 3 is formed (FIG. 2C).

  At this time, the lead-free glass for sealing has good adhesion between the semiconductor substrate 2 and the sealing layer 7, and the hermetic sealing property by the sealing layer 7 can be enhanced. Furthermore, since the lead-free glass for sealing is excellent in water resistance, moisture in the air does not adsorb to itself, and water vapor is not generated as outgas with heating and melting at the time of sealing, The function of the semiconductor device is not deteriorated. Therefore, it is possible to provide the semiconductor device 1 that is excellent in device characteristics and reliability in addition to hermetic sealing properties with good reproducibility.

  In addition, although the semiconductor device was demonstrated to the example above, the sealing object by the lead-free glass for sealing of this invention does not have a restriction | limiting in particular, For example, an electron tube, a fluorescent display tube, a fluorescent display panel, a plasma display panel, organic Examples thereof include openings and joints of various electronic parts and electrical products such as EL display panels, liquid crystal display backlight panels, and semiconductor packages.

  Next, specific examples of the present invention and evaluation results thereof will be described. In addition, the following description does not limit this invention, The modification | change in the form along the meaning of this invention is possible.

[Create lead-free glass for sealing]
Example 1
First, in terms of mass ratio, V ₂ O ₅ is 39.0%, P ₂ O ₅ is 3.0%, TeO ₂ is 51.0%, ZnO is 4.0%, BaO is 2.0%, CuO is 1 The raw material powder was mixed so that it might become 0.0%, and the lead-free glass for sealing was obtained. The transition point (Tg), softening point (Ts), and thermal expansion coefficient (average thermal expansion coefficient (α)) at 30 to 250 ° C. of the obtained lead-free glass for sealing were measured, and water resistance was further evaluated. The results are shown in Table 1.

(Examples 2 to 13)
A lead-free glass for sealing was prepared in the same manner as in Example 1 except that the composition of the lead-free glass for sealing was changed to the conditions shown in Tables 1 and 2. Table 1 and Table 2 show the transition point, softening point, thermal expansion coefficient, and water resistance evaluation of the lead-free glass for sealing obtained at that time.

[Transition point, softening point]
Using a differential thermal analyzer (TG-8110 manufactured by Rigaku Corporation), α-alumina was used as a reference (standard sample), and the sample glass was measured under the measurement conditions of a heating rate of 10 ° C./min and a temperature range of 25 ° C. (room temperature) to 500 ° C. The transition point [Tg] and the softening point [Ts] were measured.

[Average thermal expansion coefficient (α)]
The average thermal expansion coefficient (α) was measured with a thermomechanical analyzer (TMA8310 manufactured by Rigaku Corporation). In this measurement, lead-free glass (30 g) for sealing is melted and cured in a mold and formed into a cylinder of 5 mmΦ × 20 mm (sample diameter × height), and an upper bottom surface formed in parallel is used as a measurement sample. The temperature was increased from 25 ° C. (room temperature) to 250 ° C. at a rate of 10 ° C./min, and the average thermal expansion coefficient (α) was determined. Moreover, quartz glass was used for the standard sample. Although it is a thing of the lead-free glass for sealing described in the said Table 1 and 2, as an average thermal expansion coefficient ((alpha)) of the sealing material which mix | blended the inorganic filler, 70-100x10 < ^-7 > / degreeC is preferable. .

[Glass crystallization]
Crystallization was judged by whether or not a crystallization peak appeared when measurement was performed in a range of 25 ° C. (room temperature) to 500 ° C. with a differential thermal analyzer (TG-8110 manufactured by Rigaku Corporation).

(Water resistance evaluation)
Each lead-free glass (30 g) for sealing is melted and cured in a mold to form a cylinder of 5 mmΦ × 20 mm (sample diameter × height), and each columnar sample is stored in a container containing 20 mL of ion-exchanged water. Immerse in water, place the container in a thermostat set at 45 ° C, take out the sample after 72 hours, dry at 60 ° C for 2 hours, measure the mass of the sample after natural cooling, The mass reduction rate was calculated. The water resistance was evaluated based on a mass reduction rate of ◎ ... 0 to 0.3% or less, ○ ... more than 0.3% to 1.0%, x ... more than 1.0%.

(Comparative Examples 1-6)
A lead-free glass for sealing was prepared in the same manner as in Example 1 except that the composition of the lead-free glass for sealing was changed to the conditions shown in Tables 3 and 4. Table 3 and Table 4 show the transition point (Tg), softening point (Ts), average thermal expansion coefficient (α), and water resistance evaluation of the lead-free glass for sealing obtained at that time.

[Creation of sealing material paste]
(Example 14)
The lead-free glass for sealing obtained in Example 1 and cordierite powder as a low expansion filler were prepared. Further, 10% by mass of ethyl cellulose as a binder component was dissolved in 90% by mass of a solvent composed of butyl carbitol acetate to prepare a vehicle.

  A sealing material was prepared by mixing 90% by volume of the above-mentioned lead-free glass for sealing and 10% by volume of cordierite powder. A sealing material paste was prepared by mixing 80% by mass of the sealing material with 20% by mass of the vehicle.

  Next, a sealing material paste was applied to the outer peripheral region of the sealing substrate made of a glass substrate by a screen printing method (line width: 750 μm), and then dried under conditions of 120 ° C. × 10 minutes. This coating layer was baked in a heating furnace under conditions of 400 ° C. × 10 minutes, thereby forming a sealing material layer on the glass substrate.

  Next, a sealing substrate having a sealing material layer and a glass substrate of the same material were laminated. The laminate of the sealing substrate and the glass substrate was placed in a heating furnace and heat-treated at 400 ° C. for 10 minutes to seal the sealing substrate and the glass substrate. Next, the sealing properties of the semiconductor devices thus fabricated were evaluated, and the results are shown in Table 5.

(Examples 15 to 19)
A sealing material paste was prepared in the same manner as in Example 14, except that the type of sealing lead-free glass used and the blending ratio of cordierite were changed to the conditions shown in Table 5. Further, in the same manner as in Example 14 except that these sealing material pastes were used, a sealing material layer forming step on the sealing substrate, and a sealing step between the sealing substrate and the glass substrate made of the same material (Heating step) was performed. Next, the sealing property of the glass substrate thus prepared was evaluated, and the results are shown in Table 5.

[Sealability]
Regarding the glass substrate laminates of Examples 14 to 19, the glass substrate made of the same material as the sealing substrate was sealed, and the unsealed glass substrate was marked x.

  As is clear from Tables 1 to 4, the lead-free glass for sealing obtained in Examples 1 to 13 has a melting point as low as 375 ° C. or lower and very excellent water resistance. Moreover, it turned out that the sealing material paste obtained using this lead-free glass for sealing has favorable sealing property, and can fully endure practical use.

  The lead-free glass, sealing material, and sealing paste of the present invention can be used in a low temperature range, have excellent water resistance, and have good sealing properties, so that various electronic products and electrical products can be used. Can be widely used for sealing.

  DESCRIPTION OF SYMBOLS 1 ... Semiconductor device, 2 ... Element semiconductor substrate, 2a, 3a ... Surface, 3 ... Sealing substrate, 4 ... Element part, 5 ... 1st sealing area | region, 6 ... 2nd sealing area | region, 7 ... Sealing layer, 8 ... sealing material layer

Claims (8)

And _V 2 _{O 5} of 10 to 55 wt%, and _P 2 _{O 5} of 1 to 10 mass%, and TeO ₂ of from 32.5 to 54.5 wt%, and 0-13 wt% of ZnO, 0 to 13 It contains 1% by mass of BaO and 1-6% by mass of CuO, and ZnO and BaO have a total amount of ZnO + BaO in the range of 0 to 13% by mass and substantially contain PbO and Fe ₂ O ₃ . Lead-free glass for sealing, characterized by not. The lead-free glass for sealing according to claim 1, wherein the blending amount of the V ₂ O ₅ is 15 to 50% by mass and the blending amount of the TeO ₂ is 32.5 to 54.5% by mass.   The lead-free glass for sealing according to claim 1 or 2, which does not crystallize at a temperature of 500 ° C or lower.   The lead-free glass for sealing according to any one of claims 1 to 3, wherein the softening point is 375 ° C or lower.   The lead-free glass for sealing according to any one of claims 1 to 4, wherein a mass reduction rate when immersed in ion-exchanged water at 45 ° C for 72 hours is 0.3% or less.   A sealing material comprising the lead-free glass for sealing according to any one of claims 1 to 5 and an inorganic filler in the range of 0 to 40% by volume.   The inorganic filler is at least one selected from silica, alumina, zirconia, zirconium silicate, aluminum titanate, mullite, cordierite, eucryptite, spodumene, zirconium phosphate compound, tin oxide compound, and quartz solid solution. The sealing material according to claim 6, wherein the sealing material is a low expansion filler.   A sealing material paste comprising a mixture of the sealing material according to claim 6 or 7 and a vehicle.

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