JP5545589B2 - Manufacturing method of sealing material - Google Patents

Description

The present invention relates to a method for producing a sealing material suitable for a ceramic package or a flat display device. In particular, the present invention relates to a method for producing a sealing material suitable for an IC ceramic package or a plasma display panel (hereinafter referred to as PDP).

  Conventionally, glass has been used as a sealing material for ceramic packages and the like. Glass is excellent in chemical durability and heat resistance as compared with a resin-based adhesive, and is suitable for ensuring airtightness of a ceramic package or the like.

  These glasses are required to have various properties such as mechanical strength, fluidity, and electrical insulation depending on the application, but are required to be usable at least at temperatures that do not deteriorate the components used in ceramic packages. The Therefore, a low melting point lead borate glass has been widely used as a glass satisfying the above characteristics (see Patent Document 1).

However, recently, environmental problems have been pointed out with respect to PbO contained in lead borate glass, and it is desired to replace lead borate glass with lead-free glass containing no PbO. For this reason, various lead-free glasses have been developed as substitutes for lead borate glass. In particular, bismuth-based glass (Bi ₂ O ₃ —B ₂ O ₃ -based glass) described in Patent Document 2 and the like has characteristics that are substantially equivalent to those of lead borate glass, such as thermal expansion coefficient. Although it is a promising alternative candidate, the reality is that characteristics such as fluidity and thermal stability still do not reach the lead borate glass.

Bismuth-based glass usually has a thermal expansion coefficient of about 10 to 120 × 10 ⁻⁷ / ° C., and using these, high strain point glass (about 85 × 10 ⁻⁷ / ° C.), alumina substrate (about (76 × 10 ⁻⁷ / ° C.) or the like is sealed, a large tensile stress remains inside the sealing layer (sealed portion formed of the sealing material), which causes cracks and cracks. For this reason, a sealing material is generally used in which a low expansion refractory filler powder is added to bismuth glass powder to match the thermal expansion coefficient of the object to be sealed.

Generally, as the refractory filler powder, willemite, cordierite, β-eucryptite, zircon, tin oxide, mullite, alumina, zirconia and the like are used. Moreover, it is known that the thermal expansion coefficient of the sealing material decreases as the content of the refractory filler powder increases.
Japanese Unexamined Patent Publication No. Sho 63-315536 JP 2003-095597 A

  As described above, as the content of the refractory filler powder is increased, the thermal expansion coefficient of the sealing material is lowered, but the fluidity of the sealing material is easily lowered accompanying this. If the fluidity of the sealing material is lowered, it becomes difficult to seal the object to be sealed at a low temperature, and the sealing conditions required for various applications cannot be satisfied. For example, if the IC ceramic package is sealed at a high temperature after the IC element is mounted on the IC ceramic package, the characteristics of the IC element are likely to be deteriorated, resulting in a problem that the product yield is reduced. Therefore, the sealing material used for this application is required to be able to be sealed at a low temperature of 460 ° C. or lower.

By the way, conventionally, attempts have been actively made to improve the glass composition as a means for improving the fluidity of the sealing material. However, in reality, almost no attempt has been made to improve the fluidity of the sealing material by improving the refractory filler powder. As described above, bismuth-based glass has a problem in fluidity, and thus has a great benefit in improving the refractory filler powder. Further, in the bismuth-based glass, when the content of Bi ₂ O ₃ in the glass composition is large, for example, when the content of Bi ₂ O ₃ is 76% by mass or more, the content of components other than Bi ₂ O ₃ Is relatively less, and there is less room for improving the glass composition. In that case, the benefits of improving the refractory filler powder are greater.

  Accordingly, the present invention provides a sealing material containing bismuth-based glass powder and a refractory filler powder, improving the refractory filler powder and improving the fluidity of the sealing material, thereby providing a ceramic package or a flat display device. It is a technical problem to improve the characteristics of these.

As a result of diligent efforts, the inventor has regulated the content of the refractory filler powder to 5 to 50% by volume in the sealing material containing the bismuth-based glass powder and the refractory filler powder. The present inventors have found that the above technical problem can be solved by making the shape substantially spherical, and propose as the present invention. That is, the sealing material according to the present invention is a sealing material containing a bismuth-based glass powder and a refractory filler powder, wherein the content of the refractory filler powder is 5 to 50% by volume, and the refractory filler powder is substantially the same. It is spherical, and the surface of the refractory filler powder, the average particle diameter D _50, characterized in that the crystal powder is adhered to 1 nm to 1 [mu] m. Here, “substantially spherical” as used in the present invention is not limited to a true sphere. For example, in a refractory filler powder, the shortest diameter passing through the center of gravity of the refractory filler powder is divided by the longest diameter. A value of 0.5 or more, preferably 0.7 or more. The “bismuth-based glass” as used in the present invention refers to the case where the content of Bi ₂ O ₃ in the glass composition is 20% by mass or more, desirably 67 to 90% by mass, more desirably 76 to 90% by mass. . “Average particle diameter D ₅₀ of crystal powder” refers to a value obtained by measuring the primary particle diameter of crystal powder.

The sealing material according to the present invention contains bismuth glass powder. Bismuth-based glass has better thermal stability and a lower melting point than other lead-free glasses.

The sealing material which concerns on this invention contains 5-50 volume% of refractory filler powders. In this way, the thermal expansion coefficient of the sealing material is high strain point glass (thermal expansion coefficient: about 85 × 10 ⁻⁷ / ° C.), alumina substrate (thermal expansion coefficient: about 76 × 10 ⁻⁷ / ° C.), etc. The thermal expansion coefficient can be matched. Here, it is important that the thermal expansion coefficient of the sealing material is designed to be about 5 to 30 × 10 ⁻⁷ / ° C. lower than the sealed object. This is because the stress remaining in the sealing layer is set to the compression side to prevent cracking of the sealing layer. When the content of the refractory filler powder is more than 50% by volume, the content of the glass powder that is a flux is relatively reduced, and the fluidity of the sealing material is likely to be lowered.

In the sealing material according to the present invention , the shape of the refractory filler powder is substantially spherical. If it does in this way, when glass powder softens, the fluidity of glass powder will become difficult to be inhibited by refractory filler powder, and as a result, the fluidity of sealing material will improve. Moreover, when the shape of the refractory filler powder is substantially spherical, it becomes easy to obtain a smooth glaze layer. Furthermore, if the shape of the refractory filler powder is substantially spherical, even if a part of the refractory filler powder is exposed on the surface of the glaze layer, the stress of the refractory filler powder is substantially spherical, so the stress in this part is Even if the object to be sealed is dispersed and brought into contact with the glaze layer, undue stress is hardly applied to the object to be sealed, and as a result, airtightness of the ceramic package or the like is easily secured.

  Methods for obtaining a substantially spherical refractory filler powder include methods such as (1) melting method, (2) granulation method, and (3) crystallized glass method. (1) The melting method is a method of obtaining a refractory filler powder by passing a finely pulverized material of the refractory filler powder through a high-temperature atmosphere to make the refractory filler powder substantially spherical by surface tension and then rapidly cooling it. It is. (2) The granulation method is a method of obtaining a refractory filler powder by granulating the raw material of the refractory filler powder that has been pre-fired into a substantially spherical shape, followed by firing. (3) The crystallized glass method is a method described later.

In the sealing material according to the present invention, the refractory filler powder is preferably cordierite.

Sealing material according to the present invention preferably has an average particle diameter D ₅₀ of the refractory filler powder is 1～35Myuemu. Here, “average particle diameter D ₅₀ ” refers to a value measured by a laser diffraction method.

Sealing material according to the present invention, the bismuth-based glass powder, as a glass composition, in mass% in terms of _{oxide, Bi 2 O 3 67~90%,} B 2 O 3 2~12%, Al 2 O _{3 0~5%, ZnO 1~20%,} BaO 0~10%, 0~5% CuO, Fe 2 O 3 0~3%, CeO 2 0~5%, containing _Sb 2 O 3 _0~5% It is preferable.

It is preferable that the sealing material according to the present invention does not substantially contain PbO. Here, “substantially not containing PbO” in the present invention refers to a case where the content of PbO in the sealing material is 1000 ppm or less.

The sealing material according to the present invention is a sealing material containing a bismuth glass powder and a refractory filler powder, wherein the content of the refractory filler powder is 5 to 50% by volume, and the refractory filler powder is crystallized. It is preferable to be produced by a glass method. Here, the “crystallized glass method” means that a glass raw material prepared to have a desired composition is first melted, molded and pulverized to produce a crystalline glass powder, and then these are fired to be crystallized. This refers to a method of obtaining a refractory filler powder.

  As described above, the crystallized glass method uses crystalline glass powder as a raw material. Therefore, if a refractory filler powder is produced by the crystallized glass method, a homogeneous refractory filler powder can be obtained, and a refractory filler powder can be obtained by short-time firing. In addition, if a refractory filler powder is produced by the crystallized glass method, a homogeneous refractory filler powder can be obtained, so that when the sealing material is baked, unreacted materials during the refractory filler firing are contained in the glass. There is less possibility of melting, and it becomes difficult to hinder the fluidity and thermal stability of the sealing material.

The sealing material according to the present invention further contains one or more selected from the group of SiO ₂ , Al ₂ O ₃ , ZnO, and ZrO ₂ as crystal powder, and the average particle diameter of the crystal powder it is preferred D ₅₀ is 1 nm to 1 [mu] m. Here, the “average particle diameter D ₅₀ of the crystal powder” refers to a value obtained by measuring the primary particle diameter of the crystal powder.

Sealing material according to the present invention, as a crystalline _powder, which contains _{SiO 2, Al 2 O 3,} ZnO, one or two or more selected from the group of ZrO _2. More specifically, when preparing the refractory filler powder, one or two or more kinds of crystal powders selected from the group of SiO ₂ , Al ₂ O ₃ , ZnO, and ZrO ₂ are added to the raw crystalline glass powder. ing. If these crystal powders are added to the crystalline glass powder, the crystalline glass powder tends to be substantially spherical due to the surface tension during firing of the refractory filler, and the fluidity of the sealing material can be improved.

FIG. 1 is an electron micrograph showing a crystalline glass powder that is a raw material of a refractory filler powder (cordierite) according to the present invention, and an electron showing a crystalline glass powder to which Al ₂ O ₃ has been added as a crystalline powder. It is a micrograph. FIG. 2 is an electron micrograph showing the refractory powder according to the present invention, and is an electron micrograph showing the refractory filler powder obtained by firing the sample of FIG. As is apparent from FIGS. 1 and 2, the refractory filler powder can be made into a substantially spherical shape by baking the crystalline glass powder after adding the crystalline powder.

In the sealing material according to the present invention, when regulating the average particle diameter D ₅₀ of the crystalline powder to 1 nm to 1 [mu] m, can be uniformly coated with crystalline glass powder, as a result, the refractory filler powder substantially spherical While becoming easy to obtain, the manufacturing process of a refractory filler powder can be simplified.

The sealing material according to the present invention preferably has a crystal powder content of 0.03 to 3% by volume.

The sealing material according to the present invention is preferably used for sealing a flat display device or a ceramic package.

Method for producing a sealing material of the present invention is a method of manufacturing a sealing material containing a bismuth-based glass powder and the refractory filler powder, the crystallized glass method, the average particle diameter D ₅₀ is crystalline powder 1nm~1μm It is characterized by producing an attached refractory filler powder.

In the method for producing a sealing material of the present invention, the crystal powder is preferably Al ₂ O ₃ .

  In the method for producing a sealing material of the present invention, the refractory filler powder is preferably cordierite.

In the sealing material according to the present invention , the mixing ratio of the refractory filler powder is preferably 50 to 95% by volume for the bismuth glass powder and 5 to 50% by volume for the refractory filler powder, and 40% for the bismuth glass powder. It is more preferable that it is -90 volume% and refractory filler powder 10-60 volume%, and it is still more preferable that bismuth-type glass powder is 60-80 volume% and refractory filler powder 20-40 volume%. The reason why the ratio of the two is defined in this way is that if the amount of the refractory filler powder is less than 5% by volume, it becomes difficult to enjoy the effect of the refractory filler powder. This is because it becomes difficult to seal the ceramic package or the like.

In the sealing material according to the present invention , the value obtained by dividing the shortest diameter passing through the center of gravity of the refractory filler powder by the longest diameter is 0.5 or more, preferably 0.6 or more, more preferably 0.7 or more, More preferably, it is 0.75 or more. When the value obtained by dividing the shortest diameter of the refractory filler powder by the longest diameter is less than 0.5, when the glass powder softens, the flowability of the glass powder is likely to be hindered by the refractory filler powder. As a result, the fluidity of the sealing material becomes poor. Further, when the value obtained by dividing the shortest diameter of the refractory filler powder by the longest diameter is less than 0.5, it becomes difficult to obtain a smooth glaze film, and a part of the refractory filler powder is formed on the surface of the glaze film. When exposed, stress tends to concentrate on this part, and when sealing, when the sealing object comes into contact with the glaze film, undue stress is likely to be applied to the sealing object, resulting in airtightness of ceramic packages, etc. It becomes difficult to secure.

In the sealing material according to the present invention, the refractory filler powder is preferably cordierite, willemite, zircon, zirconium phosphate, β-quartz solid solution, zinc petalite, β-eucryptite, garnite and the like. These refractory filler powders not only have a large effect of reducing the coefficient of thermal expansion, but also have good compatibility with bismuth-based glass, and do not easily impair the thermal stability of the sealing material. In particular, cordierite powder is preferable because it has a small coefficient of thermal expansion and good compatibility with bismuth glass. In addition, for the purpose of increasing the mechanical strength and the like of the sealing material, a refractory filler powder other than the refractory filler powder can be appropriately added within a range not impairing the characteristics.

In the sealing material according to the present invention , the average particle diameter D50 of the refractory filler powder is preferably 1 to 35 μm, ₅ to 20 μm, particularly preferably 7 to 15 μm. When the average particle diameter D ₅₀ of the refractory filler powder is smaller than 1 μm, the fire-resistant filler powder is easily dissolved in the glass during firing of the sealing material, and the compatibility between the bismuth-based glass powder and the refractory filler powder is low In addition, the thermal stability of the sealing material tends to be lowered. Further, the average particle diameter D ₅₀ of the refractory filler powder 1μm less, during the firing of the sealing material, dissolution of the refractory filler powder becomes excessive, the softening point of the sealing material increases unduly, cold It becomes difficult to seal. On the other hand, the average and particle size D ₅₀ is greater than 35μm of refractory filler powder, only the proportion of coarse components of the refractory filler powder is increased relatively, the micro cracks are likely to occur in the sealing layer, the ceramic package Airtight defects are likely to occur. The average and particle size D ₅₀ is greater than 35μm of refractory filler powder, if the average particle diameter D ₅₀ of the bismuth-based glass powder is small, it becomes difficult to uniformly mix the bismuth-based glass powder and the refractory filler powder In addition, when the sealing material is a paste material, the bismuth-based glass powder and the refractory filler powder are easily separated, and the life of the paste material (so-called pot life) is shortened.

In the sealing material according to the present invention, the bismuth-based glass powder has a glass composition represented by mass% in terms of the following oxide, Bi ₂ O ₃ 67 to 90%, B ₂ O ₃ 2 to 12%, Al ₂ O. _{3 0~5%, ZnO 1~20%,} BaO 0~10%, 0~5% CuO, Fe 2 O 3 0~3%, CeO 2 0~5%, containing _Sb 2 O 3 _0~5% It is preferable. The reason for limiting the glass composition range of the bismuth-based glass powder as described above will be described below.

Bi ₂ O ₃ is a main component for lowering the softening point. The content is 67 to 90%, preferably 70 to 89%, more preferably 74 to 88%, and still more preferably 76 to 86%. If the content of Bi ₂ O ₃ is less than 67%, the softening point of the glass becomes too high and sealing becomes difficult at a low temperature of 460 ° C. or lower. On the other hand, when the content of Bi ₂ O ₃ is more than 90%, the glass becomes thermally unstable, and the glass tends to devitrify during melting or firing.

B ₂ O ₃ is a component that forms a glass network of bismuth-based glass and is an essential component. The content is 2 to 12%, preferably 3 to 10%, more preferably 4 to 9.5%, and still more preferably 5 to 9%. If the content of B ₂ O ₃ is less than 2%, the glass becomes thermally unstable, and the glass tends to devitrify during melting or firing. On the other hand, if the content of B ₂ O ₃ is more than 12%, the viscosity of the glass becomes too high, and it becomes difficult to seal at a low temperature of 460 ° C. or less.

Al ₂ O ₃ is a component that improves the weather resistance of the glass. Its content is 0-5%, preferably 0-2%. If the content of Al ₂ O ₃ is more than 5%, the softening point of the glass becomes too high, and it becomes difficult to seal at a low temperature of 460 ° C. or lower.

SiO ₂ is a component that improves the weather resistance of glass. Its content is 0 to 10%, preferably 0 to 3%. When the content of SiO ₂ is more than 10%, the softening point of the glass becomes too high, and it becomes difficult to seal at a low temperature of 460 ° C. or lower.

  ZnO has the effect of suppressing devitrification of the glass during melting or firing. The content is 1 to 20%, preferably 3 to 18%, more preferably 4 to 17%, still more preferably 5 to 15%. When the content of ZnO is less than 1%, it becomes difficult to obtain an effect of suppressing devitrification of the glass during melting or firing. When the content of ZnO is more than 20%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

  BaO, SrO, MgO, and CaO are components that have an effect of suppressing devitrification of the glass during melting or firing. These components can be contained in the glass composition up to 15% in total. When the total amount of these components is more than 15%, the softening point of the glass becomes too high, and sealing becomes difficult at a low temperature of 460 ° C. or lower.

  The content of BaO is 0 to 10%, preferably 0 to 8%, more preferably 0 to 6%. When the content of BaO is more than 10%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified. Further, from the viewpoint of improving the thermal stability of the glass, the BaO content is preferably 1% or more.

  Each content of SrO, MgO, and CaO is preferably 0 to 5%, and more preferably 0 to 2%. When the content of each component is more than 5%, the glass is easily devitrified or phase-separated.

  CuO has an effect of suppressing devitrification of the glass at the time of melting or firing, and can be added up to 5%. When the content of CuO is more than 5%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired. As a result, the glass is easily devitrified, and the fluidity of the glass is easily impaired. Become. Further, from the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of CuO, and specifically, the content of CuO is preferably 0.01% or more.

Fe ₂ O ₃ has an effect of suppressing devitrification of the glass during melting or firing, and its content is 0 to 3%, preferably 0 to 1.5%. When the content of Fe ₂ O ₃ is more than 3%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified. From the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of Fe ₂ O ₃ , and specifically, the content of Fe ₂ O ₃ is preferably 0.01% or more.

CeO ₂ has an effect of suppressing devitrification of the glass at the time of melting or firing, and its content is 0 to 5%, preferably 0 to 2%, more preferably 0 to 1%. When the content of CeO ₂ is more than 5%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified, and the fluidity of the glass is impaired. It becomes easy. Further, from the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of CeO ₂ , and specifically, the content of CeO ₂ is preferably 0.01% or more.

Sb ₂ O ₃ is a component for suppressing devitrification of the glass, and its content is 0 to 5%, preferably 0 to 2%, more preferably 0 to 1%. Sb ₂ O ₃ has an effect of stabilizing the network structure of the bismuth-based glass. If Sb ₂ O ₃ is appropriately added to the bismuth-based glass, when the content of Bi ₂ O ₃ is large, for example, Bi ₂ O 3 _{Even if} the content of ₃ is 76% or more, the thermal stability of the glass is hardly lowered. However, when the content of Sb ₂ O ₃ is more than 5%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified. Further, from the viewpoint of improving the thermal stability of the glass, it is preferable to add a small amount of Sb ₂ O ₃ , and specifically, the content of Sb ₂ O ₃ is preferably 0.05% or more.

  In addition to the above components, for example, the following components can be contained in the glass composition.

WO ₃ is a component for suppressing devitrification of the glass, and its content is preferably 0 to 10%, particularly preferably 0 to 2%. When the content of WO ₃ is more than 10%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is easily devitrified.

In ₂ O ₃ and Ga ₂ O ₃ are not essential components, but are components for suppressing devitrification of the glass, and the total content is preferably 0 to 5%, particularly preferably 0 to 3%. If the total content of In ₂ O ₃ and Ga ₂ O ₃ is more than 5%, the balance in the glass composition is lost, and conversely, the thermal stability of the glass is impaired, and as a result, the glass is devitrified. It becomes easy. In addition, the content of In ₂ O ₃ is more preferably 0 to 1%, and the content of Ga ₂ O ₃ is more preferably 0 to 0.5%.

  The Li, Na, K, and Cs oxides are components that lower the softening point of the glass. However, since they have an action of promoting devitrification of the glass during melting, the total amount is preferably 2% or less.

P ₂ O ₅ is a component that suppresses the devitrification of the glass at the time of melting. However, if the amount added is more than 1%, the glass tends to phase-separate at the time of melting, which is not preferable.

MoO ₃ , La ₂ O ₃ , Y ₂ O ₃ and Gd ₂ O ₃ are components that suppress the phase separation of the glass at the time of melting. However, if the total amount of these is more than 3%, the softening point of the glass is high. It becomes difficult to fire at a temperature of 460 ° C. or less.

  Moreover, even if it is another component, it can add to a glass composition to 15% (preferably 5%) in the range which does not impair the characteristic of glass.

The bismuth glass having the above glass composition is an amorphous glass exhibiting good fluidity at a low temperature, and has a thermal expansion coefficient of about 100 to 120 × 10 ⁻⁷ / ° C. at 30 to 250 ° C.

Sealing material according to the present invention is not intended to exclude embodiments containing an PbO, as described previously, it is preferred not to substantially contain PbO environmental reasons. Moreover, when PbO is contained in the glass composition, Pb ²⁺ present in the glass diffuses, and the electrical insulation of the sealing material may be lowered.

The sealing material according to the present invention further contains a crystalline powder. The crystal powder preferably has a melting point equal to or higher than that of the refractory filler powder, and preferably has a property of not easily reacting with the crystalline glass powder as a raw material, and is selected from the group consisting of SiO ₂ , Al ₂ O ₃ , ZnO, and ZrO _2. One or more selected from the group consisting of SiO ₂ , Al ₂ O ₃ , and ZnO is more preferable. SiO ₂ , Al ₂ O ₃ , ZnO, and ZrO ₂ are easily processed into fine powders, have a high melting point, and are difficult to react with crystalline glass powder. In particular, when the refractory filler powder is cordierite, Al ₂ O ₃ is suitable because it does not easily react with the crystalline glass powder and can be easily processed into a fine powder.

In the sealing material according to the present invention, the average particle diameter _{D 50} of the crystal powder is 1 nm to 1 [mu] m, 5Nm～0.5Myuemu, particularly 8nm~0.1μm is preferred. The average particle diameter D ₅₀ of the crystal powder is 1nm less, during the firing of the refractory filler, crystalline powder is easily dissolved in the crystalline glass powder, it becomes difficult to exhibit the desired effect. On the other hand, the average particle diameter D ₅₀ of the crystalline powder is greater than 1 [mu] m, it becomes difficult to uniformly coat the crystalline glass powder, during firing of the refractory filler, crystalline glass powder particles is liable to sintering. The crystal powder preferably has a BET specific surface area of 10 to 400 m ² / g, particularly 50 to ²⁰⁰ m ² / g. When the BET specific surface area of the crystal powder is smaller than 10 m ² / g, it becomes difficult to uniformly coat the crystalline glass powder, and the crystalline glass powder is easily sintered when the refractory filler is fired. When the BET specific surface area of the crystal powder is larger than 400 m ² / g, the crystal powder is easily dissolved in the crystalline glass powder at the time of firing the refractory filler, and the desired effect is hardly exhibited.

In the sealing material according to the present invention , the content of the crystal powder is preferably 0.03 to 3% by volume, particularly preferably 0.05 to 2% by volume. When the content of the crystal powder is less than 0.03% by volume, the crystalline glass powders are strongly sintered at the time of firing the refractory filler. The powder is less likely to be substantially spherical, and the fluidity of the sealing material tends to decrease. On the other hand, when the content of the crystal powder is more than 3% by volume, the crystal powder becomes excessive, and when the sealing material is fired, the excess crystal powder is dissolved in the glass and the fluidity of the sealing material is impaired. There is a fear.

In the sealing material according to the present invention, the crystal powder is preferably attached to the refractory filler powder. If it does in this way, at the time of baking of sealing material, it will become difficult to melt | dissolve crystal powder in glass, and it will become difficult to impair the fluidity | liquidity of sealing material. In order to attach the crystal powder to the refractory filler powder, the firing conditions (firing temperature, firing time) of the refractory filler may be adjusted.

The sealing material according to the present invention is preferably used for sealing a ceramic package. The ceramic package uses a member having low heat resistance, such as an IC element or a conductive adhesive, and therefore needs to be sealed at a low temperature. In that respect, since the sealing material according to the present invention can be sealed at a low temperature, it is suitable for this application. In addition, when the fluidity of the sealing material is low, the refractory filler powder is likely to be exposed on the outer surface of the sealing layer, and undue stress is likely to remain in the exposed portion, which causes cracks in the ceramic package. It becomes easy. However, since the sealing material according to the present invention is excellent in fluidity, such a situation can be effectively avoided. Furthermore, since the sealing material according to the present invention has a substantially spherical shape, even if the refractory filler powder is exposed to the sealing layer, the stress concentration in the exposed portion can be reduced, and the ceramic package is cracked. It is possible to effectively avoid the occurrence of

The sealing material according to the present invention is particularly preferably used for sealing an IC ceramic package or a quartz crystal ceramic package. If the IC ceramic package is not sealed at a temperature of 460 ° C. or less, the IC element is deteriorated. However, the sealing material according to the present invention can be satisfactorily sealed at a temperature of 460 ° C. or less. Is preferred. If the quartz ceramic package is not sealed at a temperature of 460 ° C. or lower, the conductive adhesive is deteriorated and the element is deteriorated. However, the sealing material according to the present invention is excellent at a temperature of 460 ° C. or lower. Since it can be sealed, it is suitable for this application.

The sealing material according to the present invention is preferably used for sealing a flat display device. Since the flat display device uses a member having low heat resistance, for example, a phosphor, the necessity for sealing at a low temperature is high. In that respect, since the sealing material according to the present invention can be sealed at a low temperature, it is suitable for this application.

In the PDP manufacturing process, the sealing material undergoes the following baking process. First, the sealing material dispersed in the vehicle is applied to the outer peripheral edge of the rear glass substrate of the PDP, and primary firing (glazing process, pre-baking process) is performed, and the vehicle components are pyrolyzed or incinerated at a high temperature. The primary firing step is performed under a temperature condition where the resin used in the vehicle is completely thermally decomposed, for example, about 400 to 500 ° C. Next, the front glass substrate and the rear glass substrate of the PDP are sealed by secondary firing (sealing process, sealing process). The secondary firing step is performed under a temperature condition where the sealing material is softened and deformed, for example, about 450 to 500 ° C. Finally, the inside of the PDP is evacuated through the exhaust pipe, and then a necessary amount of rare gas is injected to seal the exhaust pipe. Since the sealing material which concerns on this invention is excellent in fluidity | liquidity and excellent in thermal stability, it can be used conveniently at the said process. Further, when the fluidity of the sealing material is low, the refractory filler powder is likely to be exposed on the outer surface of the glaze layer after the primary firing, and if the front glass substrate is brought into contact with this exposed portion, Cracks are likely to occur at the contact part. However, since the sealing material according to the present invention is excellent in fluidity, such a situation can be effectively avoided. Furthermore, when the sealing material contains crystal powder, even if the refractory filler powder is exposed to the glaze layer after the primary firing, since the shape is substantially spherical, the stress concentration in the exposed portion can be reduced. Thus, it is possible to effectively avoid the occurrence of cracks in the flat display device.

The method for producing a sealing material of the present invention is characterized in that, in the method for producing a sealing material containing a bismuth-based glass powder and a refractory filler powder, the refractory filler powder is produced by a crystallized glass method. Moreover, it is preferable that the manufacturing method of the sealing material of this invention adds crystal powder, when grind | pulverizing the crystalline glass used as the raw material of a refractory filler powder. If the crystalline glass is added when the crystalline glass is pulverized, the step of mixing the crystalline glass powder and the crystalline powder can be omitted, and the crystalline glass powder and the crystalline powder can be mixed uniformly. Furthermore, in the method for producing a sealing material of the present invention, the refractory filler powder is more preferably cordierite. Here, the technical features (operational effects, preferred embodiments, suitable numerical ranges, etc.) of the method for producing the sealing material of the present invention are the contents already described in the description column of the sealing material according to the present invention. The description is omitted here for convenience.

When producing the refractory filler powder according to the present invention, in order to enhance the meltability of the raw crystalline glass, the glass composition of the crystalline glass includes components other than the crystalline constituents of the refractory filler powder, such as B _2. O ₃ , R ₂ O (R ₂ O refers to Li ₂ O, Na ₂ O, K ₂ O, Cs ₂ O), R′O (R′O refers to MgO, CaO, SrO, BaO) It is preferable to add 0.1-10 mass%. When these components are less than 0.1% by mass, it becomes difficult to improve the meltability of the crystalline glass. In addition, even if the glass composition of the crystalline glass powder slightly deviates from the theoretical composition of the refractory filler powder, it is possible to precipitate the desired crystals. It becomes difficult to deposit.

  When producing the refractory filler powder according to the present invention, it is preferable to provide a step of adjusting the particle size distribution of the raw crystalline glass powder, for example, a step of classifying the crystalline glass powder. In this way, the particle size distribution of the refractory filler powder can be easily adjusted.

  In the method for producing a sealing material according to the present invention, when a refractory filler powder is produced, if a crystalline powder is added, the subsequent pulverization step can be omitted, and the classification step is omitted in the refractory filler powder production step. can do. If it does in this way, while being able to improve the manufacturing efficiency of a refractory filler powder, the manufacturing cost of a refractory filler powder can be reduced. Furthermore, in the manufacturing method of the sealing material of this invention, it is preferable to have a crushing process in the manufacturing process of a refractory filler powder, and not to have a crushing process. In this way, since the crushing process is completed in a short time, the production efficiency of the refractory filler powder can be increased. Moreover, since the fine powder ratio of a refractory filler powder can be reduced in this way, the fluidity and thermal stability of the sealing material can be maintained.

In the sealing material according to the present invention , in addition to the substantially spherical refractory filler powder, other shapes of refractory filler powder can be added as necessary. Moreover, in the sealing material which concerns on this invention , the refractory filler powder produced by the other method can also be added as needed other than the refractory filler powder produced by the crystallized glass method. Examples of such a refractory filler powder include willemite, zircon, tin oxide, zirconia, alumina, cordierite, niobium oxide, β-eucryptite, titanium oxide, silica, garnite, and quartz glass.

  Hereinafter, based on an Example, this invention is demonstrated in detail. Tables 1-4 show sample No. 1-20 are shown.

  In the following manner, each of the sample Nos. 1-20 were produced.

  First, a glass batch prepared by preparing raw materials such as various oxides and carbonates so as to have the glass compositions shown in Tables 1 to 4 was prepared, and this was put in a platinum crucible and melted at 900 to 1100 ° C. for 1 to 2 hours. did. Next, a part of the molten glass was poured out into a stainless steel mold as a push rod type thermal expansion coefficient measurement (TMA) apparatus and a sample for density measurement, and the other molten glass was formed into a flake shape with a water-cooled roller. The TMA and the density measurement sample were subjected to a predetermined slow cooling treatment after molding. Finally, the glass flakes were pulverized with a ball mill and passed through a sieve having an opening of 45 μm to obtain each glass powder sample having an average particle size of about 10 μm.

  For each glass powder sample, the density, thermal expansion coefficient, glass transition point and softening point were determined. The density was measured by the well-known Archimedes method. The thermal expansion coefficient and glass transition point were measured with a TMA apparatus. In addition, the thermal expansion coefficient was measured in the temperature range of 30-300 degreeC. Furthermore, the softening point was measured with a differential thermal analysis (DTA) apparatus.

  Next, each glass powder sample of Tables 1-4 and the predetermined | prescribed refractory filler powder in a table | surface were mixed, and the sealing material shown in Tables 1-4 was obtained. Sample No. About 1-20, the flow diameter, devitrification state, surface protrusion, and crack resistance were evaluated.

  As for the flow diameter, a powder having a mass corresponding to the synthesis density of each sample was dry-pressed into a button shape having an outer diameter of 20 mm using a die, and this was pressed into a 40 mm × 40 mm × 2.8 mm thick high strain point glass substrate (NEC) It was placed on PP-8C), heated in air at a rate of 5 ° C./min, baked at 460 ° C. for 10 minutes, and then cooled to room temperature at 5 ° C./min. Evaluation was made by measuring the diameter of the button. The synthetic density is a theoretical density calculated by mixing the density of glass and the density of the refractory filler in a predetermined volume ratio. Moreover, if the flow diameter is 19 mm or more in this evaluation, it means that it can be satisfactorily sealed by baking at 460 ° C. for 10 minutes.

  The devitrification state was evaluated as follows. Sample Nos. The depressurized state was evaluated by observing the surface crystals of the sample using a stereomicroscope (magnification 200 times) after holding the powder pressure-molded bodies of 1 to 20 in a baking furnace at 460 ° C. for 10 minutes. The case where devitrification was not recognized was indicated as “◯”, and the case where devitrification was observed was indicated as “x”. The temperature raising / lowering rate was 10 ° C./min.

  The surface protrusions were evaluated as follows. First, each sample and acrylic resin-containing α-terpineol were uniformly kneaded and processed into a glass paste, and then the edge of a 100 × 100 × 3 mm high strain point glass substrate (Nippon Electric Glass Co., Ltd. PP-8C). The coating was applied linearly (80 × 3 × 3 mm) to the part and dried at 120 ° C. for 15 minutes. Next, after firing this sample, the outer surface of the obtained glaze film was confirmed with an optical microscope, and “○” indicates that part of the refractory filler powder is not exposed, part of the refractory filler powder. What was exposed was evaluated as “×”. The firing was performed in air, the temperature was increased from room temperature at a rate of 5 ° C./minute, held at 440 ° C. for 10 minutes, and then decreased to room temperature at 5 ° C./minute.

  Crack resistance was evaluated using a button-like sample that was used for measurement of the flow diameter. Observe the surface of the button-shaped sample and the glass substrate directly under the button with a stereomicroscope (200 ×). “○” indicates that the button surface and the glass substrate are not cracked, and “×” indicates that the button is generated. As evaluated.

Sample Nos. The refractory filler powders described in 1 to 15, 17 and 18 were produced by the following method. First, a glass raw material was prepared so as to obtain a predetermined crystal, and after mixing, it was melted at 1400 to 1550 ° C. to obtain a crystalline glass. Next, the obtained crystalline glass was pulverized to obtain a crystalline glass powder having an average particle diameter D ₅₀ = 10 μm. At the time of pulverization of the crystalline glass, it was added crystalline powder in the table (an average primary particle diameter D _{50 =} 20nm). Subsequently, after baking this sample for 10 hours at 1300 ° C., the obtained fired product was crushed to obtain a refractory filler powder having an average particle diameter D ₅₀ = 10 μm. In the refractory filler powder obtained by this method, the value obtained by dividing the shortest diameter passing through the center of gravity of the refractory filler powder by the longest diameter was 0.7 or more. Sample No. in Table 4 The refractory filler powder described in No. 16 was prepared by first preparing an oxide raw material so that a predetermined refractory filler powder was obtained. Next, the raw material of the refractory filler powder was granulated with a spray dryer so as to be substantially spherical, and then fired at 1400 ° C. for 10 hours to obtain a refractory filler powder having an average particle diameter D ₅₀ = 10 μm. In the refractory filler powder obtained by this method, the value obtained by dividing the shortest diameter passing through the center of gravity of the refractory filler powder by the longest diameter was 0.75 or more.

Sample No. in Table 4 The refractory filler powders described in 19 and 20 were obtained by the following method. First, an oxide raw material is prepared so that a predetermined refractory filler powder is obtained, and after mixing, calcined at 1400 ° C. for 10 hours, this calcined product is pulverized with a ball mill, and then classified with a 350 mesh sieve. A refractory filler powder having a particle size D ₅₀ = 10 μm was obtained. In the refractory filler powder obtained by this method, the value obtained by dividing the shortest diameter passing through the center of gravity of the refractory filler powder by the longest diameter was about 0.3.

  Sample Nos. Nos. 1 to 16 flowed well at 460 ° C. for 10 minutes, and had low melting point characteristics suitable for sealing ceramic packages and the like. Furthermore, sample no. In Nos. 1 to 16, since the evaluation of the devitrification state, the surface protrusion, and the crack resistance is good, it is considered that the airtightness of the ceramic package or the like can be secured.

  Sample No. in Table 4 No. 17 had poor crack resistance because the content of the refractory filler powder was outside the predetermined range. Sample No. In No. 18, since the content of the refractory filler powder was outside the predetermined range, the evaluation of fluidity and surface protrusion was poor. Sample No. In No. 18, since the content of the refractory filler powder was excessive, the evaluation of the surface protrusions was poor without causing the shape of the refractory filler powder. Sample No. In Nos. 19 and 20, since the shape of the refractory filler powder was not substantially spherical, the evaluation of fluidity and surface protrusion was poor.

The sealing material according to the present invention is suitable for a ceramic package such as a crystal resonator ceramic package and an IC ceramic package. The sealing material according to the present invention is suitable for flat display devices such as PDP, various types of field emission displays having various electron-emitting devices, organic electroluminescence displays, inorganic electroluminescence displays, and fluorescent display tubes. .

An electron micrograph showing a crystalline glass powder as a raw material for refractory filler powder according to the present invention (cordierite powder), an electron microscope photograph showing a crystalline glass powder was added for Al ₂ O ₃ crystal powder is there. It is an electron micrograph which shows the refractory filler powder (cordierite powder) which concerns on this invention, and baked the sample of FIG. 1, and is an electron micrograph which shows the obtained refractory filler powder.

Claims (4)

In the manufacturing method of the sealing material containing bismuth-based glass powder and refractory filler powder,
A method for producing a sealing material, characterized in that a refractory filler powder to which crystal powder having an average particle diameter D ₅₀ of 1 nm to 1 μm is adhered is produced by a crystallized glass method. The method for producing a sealing material according to claim 1 , wherein the crystal powder is Al ₂ O ₃ . The method for producing a sealing material according to claim 1 or 2 , wherein the refractory filler powder is cordierite. The bismuth-based glass powder has a glass composition represented by mass% in terms of the following oxide, Bi ₂ O ₃   67-90%, B ₂ O ₃   2-12%, Al ₂ O ₃   0-5%, ZnO 1-20%, BaO 0-10%, CuO 0-5%, Fe ₂ O ₃   0-3%, CeO ₂   0-5%, Sb ₂ O ₃   It contains 0 to 5%, The manufacturing method of the sealing material in any one of Claims 1-3 characterized by the above-mentioned.