DE2460931A1 - SUBSTANCE COMPOSITION SINTERABLE AT LOW TEMPERATURES - Google Patents

Description

Applicant's file number: FI 973 018

Material composition sinterable at low temperatures

The invention relates to kerar sinterable at low temperatures Mix compositions of matter with a low dielectric constant and thus glass-like ceramic insulating materials with low-i like coefficient of thermal expansion as well as a method for Manufacture of these substances.

Ceramic compositions are used in manufacture electrical switching elements and devices have been widely used. One such field of application is, for example, manufacturing of multilayer ceramic structures, generally consisting of a number of layers of ceramic insulating material and a number of layers made of a metallic conductive material.

Such multilayer ceramic structures are for example described in "Laminated Ceramics" by Schwartz et al in Proc. Electron. Comp. Conf. (Washington, D.C, 1967), page 17, in "Ceramics for Packaging" by Wilcox, in "Solid State Technology", Volume 14, 1971, page 40; "A Fabrication Technique for Multi-Layer Ceramic Modules "by Kaiser and others in" Solid State Technology ", May 1972, page 35 and" Metal-Ceramic Constraints for Multi-Layer Electronic Packages "by Chance et al. In" Proceeding of the IEEE ", Volume 59, Page 1455.

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For electronic fields of application, in particular for the multilayer ceramic structures mentioned above, one generally has Ceramic materials are used instead of glass, since ceramic materials have glass in almost all desirable properties are superior. Because of the higher dielectric constant of the ceramic material, it would be extremely desirable if one could create ceramic materials whose dielectric constant can be approximated to that of glass.

A disadvantage of many ceramic materials heretofore used for electronic applications is their relative nature high sintering temperature. When you use ceramic materials at the same time sinters together with a metallization, for example to form multilayer ceramic structures or modules, then it is usually necessary to use refractory precious metals such as platinum or palladium for metallization to be used when sintering in an oxidizing atmosphere or when refractory metals such as e.g. Use molybdenum, tungsten or moly manganese or other metals, in which case a reducing atmosphere is used for sintering must become.

It would be a significant step forward compared to the state of the art if one were suitable for electronic fields of application Ceramic materials would have been available that can be used at low temperatures in an oxidizing or reducing atmosphere sintered, since such ceramic materials with metallizations with a low melting point such as silver, Copper, gold or their alloys, e.g. Ag-Cu, Ag-Au, Ag-Pd, Au-Pd or Au-Pt etc. would be compatible.

The object of the invention is therefore to produce ceramic compositions of matter to create which can be sintered at low temperatures, e.g. in the order of magnitude between 825 and 925 C and which accordingly sintered together with metallizations of low-melting metals such as silver, copper, gold and the like

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can be used and then used in the manufacture of electronic Components of high processing speed can be used particularly cheaply. Preferably a ceramic Composition of matter can be created in a reducing or oxidizing atmosphere can be sintered. Above all, it should be achieved that the ceramic Bodies have excellent electrical properties, for example a dielectric constant, the value of which in ü the proximity of the values of the best available electrical Glasses, i.e., a dielectric constant on the order of about 4.3 to about 6.2, preferably about 4.5 to 5.2.

Above all, the new ceramic compositions should be sintered to a maximum density and therefore be absolutely impermeable to gases and liquids and be suitable for hermetic seals, especially at interfaces between ceramic materials and metals.

It would also be desirable if the ceramic Substance compositions during sintering are much smaller more linear shrinkage than most commercially available high temperature ceramics, e.g.

a) dry pressed parts - 1.5 to 8.5%

b) parts made by pouring and spreading - 3.5 to 12.0%.

The object underlying the invention is achieved through use a ceramic composition of matter dissolved, which consists of a There is glass-like, refractory material and a glass, which after sintering results in a ceramic body that consists of a Skeleton consists of a glass-like refractory material which is connected by glass lying in the interstitial area.

The invention will now be explained on the basis of ^{exemplary embodiments. FI} 973 018 509837/0794

purifies. The features to be protected can be found in the attached claims.

The glass-like, refractory skeleton, which in the present invention is a polycrystalline, ceramic material with a high dielectric constant. The glass-like, refractory The skeleton essentially gives the material the necessary flexural rigidity, the dielectric losses at high frequencies and the thermal conductivity. It supports the creation of a ceramic insulating material that meets all requirements Electronic, ceramic materials met and at the same time the parts made from them a dimensional stability and a Dimensional accuracy within the required tolerances in use

The glass-like, refractory skeleton gives the sintered ceramic Material according to the present invention properties which the glass enclosed in the interstitial region does not have, so that by balancing the properties of the ceramic material and the glass, a vitreous ceramic material is obtained which contains the desirable properties of the interstitial glass and the vitreous, refractory Material has.

The glassy, refractory material should be good electroceramic Have properties, i.e .:

a) it should have a thermal expansion that is approximately equal to the thermal expansion of the interstitial area lying glass is,

b) it should preferably have a dielectric constant in a range between about 6 and about

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9 is and should be a ceramic material in connection with the glass in the intermediate grid area deliver whose effective dielectric constant is not too far from the dielectric constant of the im Interstitial area of the lying glass is removed.

In addition to these properties, there are some preferred properties that the vitreous refractory material desirably has should have;

a) it should have low dielectric losses over the frequency range by using the ceramic body made from it, e.g. in electronic circuits for data processing systems, the dielectric loss factor should be less than 0.05 over the frequency range from 1 kHz to 200 MHz, preferably less than 0.0010; ^!

b) the bending stiffness should be very good, i.e. from '

be about 2100 kg / cm to 4200 kg / cm; i

c) it should have a good power factor of e.g. 0.00055 or less;

d) the thermal conductivity should be better than that of glass, i.e., as many prefer, according to the present invention Glass types used in the invention have a thermal conductivity on the order of about 0.0015 to about 0.003, the vitreous refractory material should have a thermal conductivity of about 0.04 to about 0.07.

The general classes of refractory vitreous materials used in the composition of matter of the present invention that allow compression in the temperature ranges used fall into three categories. These are:

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A. Acid refractories

Two-phase systems Al ₃ O ₃ -SiO ₂

1. Kyanite or sillimanite or fiber pebbles - Al ₉ O - .. SiO ₉

2. Mullite .- 3Al ₂ O ₃ .SiO ₂

B. Neutral, refractory materials Alumina - Al ₃ O ₃

C. Basic, refractory materials

1. Anorthite or lime feldspar CaO ₁ Al ₃ O ₃ ^ SiQ ₃

other BaCAl ₃ O ₃ ^ SiO ₃

MgO.Al ₃ O ₃ .2SiO ₃

2. Binary oxides
Wollastonite - CaO.SiO ₃ other BaO ₄ SiO ₃

MgO.SiO ₃ (steatite - soap stone)

3. Double silicates BaZrSiO ₅

CaZrSiO ₅
MgZrSiO ₅
ZnZrSiO ₅ Li ₃ ZrSiO ₅

4. Lithium aluminum silicates

Li ₂ O. Al ₃ O ₃ . 4SiO ₂

e.g. alpha podumene or triphane beta podumene eucryptite

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5. Normal spinnel structures

BaO.

CaO.

MgO. ₂₃

ZnO. Al ₃ O ₃

Zirconium spinel.

Mixtures of these materials can also be used. Examples of such mixtures and other useful refractories are, for example, spodumene - + - kyanite, wollastonite - + - clay, clay - + - CaSi0 ₃ , kyanite - + - CaSiO ₃ , wollastonite - + - clay and others ceramic spinel structures, forsterite (2MgO.SiO), cordierite (2MgO.2Al ₂ O ₃ .5SiO ₂ ) zircon (ZrSiO ₄ ), etc.

The glass located in the interstitial area has according to the present Invention two determinations. It serves both as a binder and as a flux (for sintering in the liquid phase) and is responsible for the fact that the ceramic material compacts at lower sintering temperatures.

The glass arranged in the interstitial area is essential for three " and highly desirable properties of the sintered ceramic material according to the present invention responsible:

(a) for the low sintering temperature

(b) for the low dielectric constants

(c) for the low thermal expansion.

The glass lying in the interstitial area should melt in the desired temperature range of about 825 to about 925 ⁰ C and thus create the necessary bond that holds the skeleton made of refractory material together and is responsible for the dimensional stability of the ceramic bodies produced in this way.

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• a-

In this regard, the interstitial glass can be viewed as a matrix in which the refractory Particles are uniformly distributed throughout the mass, creating a compromise between the desired electroceramic Properties of both the glass lying in the interstitial area and the refractory material result in

The glass located in the interstitial area should have a low coefficient of thermal expansion, for example of the order of magnitude of 5.0 10 ~ * or less, preferably of about 2.5 up to about 4.5 χ 10 cm / cm / C in combination with a low one Have dielectric constant of, for example, less than 5, with dielectric constants in the range between 4.1 and 4.2 for multilayer ceramic structures produce excellent results. It is special about it It is desirable that the interstitial glass should be sintered in a reducing atmosphere one used, experiences only a slight discoloration.

The disposed in the interstitial area glass should achieve a high degree of densification during sintering _t, for example of the order 93-98% of the theoretical density at a temperature between 825 ⁰ C and 925 ⁰ C.

During the sintering, the interstitial area melts Glass initially and fills the cavities between the refractory particles in the interstitial area. That Flow of the glass also results in a binding effect at the interface between ceramic material and metal, thereby creating a gives a kind of hermetic seal. The glass in the interstitial area should have the smallest possible proportion of sodium or Have potassium ions so that no ion conduction takes place at the interfaces with electrical circuits if possible. If the fired ceramic material composition according to the present invention in a layer arrangement with internal

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gender metallization is used, then of course the glass lying in the interstitial area should be the inner metallization wet.

The glasses preferably used in connection with the present invention and arranged in the interstitial region are borosilicate or aluminum-borosilicate glasses including binary, ternary and quaternary glasses of this type, for example from the systems B ₂ O ₃ -SiO ₂ , Al ₂ O ₃ -B ₂ O ₂ -SiO ₂ or Li ₂ O-Al ₂ O ₃ -B ₂ O ₃ -SiO ₂ .

Further preferred types of glass are boron phosphate and lithium titraborate glasses.

Preferred glasses in the interstitial area have a power factor of about 0.05 or less.

The ratio between refractory components and the glass in the manufacture of the ceramic composition according to of the present invention is defined to determine the following properties:

(a) the desired dielectric properties

(b) the desired thermal expansion and i

(c) compaction at low temperatures.

To get optimal dielectric properties, optimal thermal; To achieve expansion and compression, the ceramic material composition is generally about 65 to about ι 25% glass and correspondingly 35 to about 75% of refractory material, but preferably 35 to 50% glass and between! 65 and 50% refractory, all of these percentages being percentages by weight.

The higher the percentage of glass, the lower the dielectric constant, the thermal expansion and the sintering temperature, with the opposite effect with correspondingly low

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- ".0 percentages of the glass content is effected.

The person skilled in the art will immediately recognize that for various fields of application the various ceramic properties have different meanings and are generally present in the present Invention for the formation of multilayer ceramic composite structures the following ceramic properties the most important:

(a) compression in the range between 825 and 925 ⁰ C;

(b) a low dielectric constant, i.e. between the interstitial glass and the vitreous, refractory material, preferably in the range between 4.3 and about 5.3;

(c) a coefficient of thermal expansion on the order of the coefficient for that in the interstitial region lying glass, d * h. less than 5 χ 10 ~ mm / mm / ° C.

In the fired ceramic material according to the present invention, initially appears between that in the interstitial area lying glass and the refractory material to take place a reaction. It does not seem to be the case that according to the Invention used sintered area a complete chemical reaction takes place between these two phases, which then results a completely different, crystalline phase could result from the starting ingredients.

Analysis by the X-ray diffraction method appears to confirm this conclusion.

The fired ceramic material according to the present invention preferably shows a Moh's hardness of about 4 to about 7, preferably about 6 and allows lapping and polishing, which can be carried out quickly and cheaply in comparison with other ceramic materials with a high alumina content. The upper

—3 surface fineness is about 0.025 χ 10 mm and can be

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fired ceramic compositions of matter according to the present invention Invention can be achieved so that a metallic deposit can be carried out with all known methods.

The ceramic compositions of matter produced at low temperature according to the present invention, which is particularly useful for the manufacture of multilayer ceramic structures which are used in the development of data processing systems offer several very important advantages.

However, this allows lower sintering temperatures to be used, which represents a major advance.

One can use very simple sintering conditions, i.e. either sinter in an oxidizing atmosphere or in a reducing atmosphere, such as with a wet gas, which is essential is easier to use than hydrogen.

The compositions of matter can be in simple apparatus, such as e.g. continuous furnace.

The compositions of matter have a low melting point (below 1100 ^° C.), so that materials with a low specific resistance can be used together with these materials. For example, you can use a gold metallization, which shows a very high resistance to corrosion under harmful environmental influences.

The low dielectric constants of the ceramic materials according to the present invention have a delay that is a factor of / 1 smaller than that of ceramic materials with a high alumina content, so that delay lines with a characteristic impedance Z of the order of 65 to 76 ohms can be constructed during the characteristic impedance Z for ceramic materials with a high alumina content is a maximum of 55 ohms.

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- re -

The higher characteristic impedance allows better impedance matching to other electrical components and assemblies.

The thermal expansion of the constructed in accordance with the present invention ceramic materials is better adapted to semi-flexible plates made of silicon and the ceramic materials show significantly better properties when treated with thermal shock in the alternating stress test. You can also do it together use with the new ceramic materials according to the invention much larger silicon semiconductor wafers than before.

The behavior of the ceramic materials according to the invention in thermal shock is significantly better than that of ceramic materials with high alumina content.

The wide range of inorganic materials used to form the ceramic materials or compositions of matter according to the present invention Invention can be used, allows a wide selection of materials to be used, which is broad Can adapt range of application areas.

The Moh's hardness of the ceramic materials according to the present Invention is smaller than common high-alumina ceramic materials, making them lighter, faster and can be machined more economically without crater formation and still achieve a surface quality that is suitable for mechanically drilling the appropriate holes for alignment with the aid of a laser or an electron beam and for the metallic connections, whereupon you can then, for example, screen printing the appropriate Metallization for the holes in the Z-direction and other electrical conductors for the power supply and the ground connection can muster.

Of course, it is clear that the metallization will be chosen so that it also corresponds to the sintering temperature to be used later

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withstands and one will mostly use a metal or a combination of metals that have a low specific resistance such as platinum, gold, silver, copper, aluminum or alloys such as Ag-Cu, Ag-Au, Au-Pd or Au-Pt, Ag-Pd etc. Refractory metals are generally used because of their high melting point and because of their high resistivity not used.

The metallization is generally made from commercially available electrode pastes, some of which have been specially developed for ceramic bodies, which are generally gold, gold platinum and silver palladium pastes. Pastes that can be applied with a rubber squeeze provide a useful bond at the interface between ceramic material and metal and provide good tensile strength for soldering connection pins and the like. Metallization was when they excluded a soldering or a brazing <

will not go into solution. i

When the metallization is applied to the top surface ' it should be suitable for a connection with; Micro-miniature switching elements or circuits such as j Manufacture silicon chips and the like. The metallization located on the outer surface can be easily removed and galvanize economically in order to prevent corrosion when this metallization has harmful environmental influences is exposed.

Although the green ceramic sheet can theoretically be used as a laminate with other green sheets without layering, if if they are thick enough they will generally with others green foils of the same or different composition of matter are put together to form a monolithic device. For example, other such green ceramic films can not only consist of similar or identical ceramic Compositions of matter are produced, but also of ceramic compositions of matter, as for example in

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2Λ60931

U.S. Patent 3,540,894 entitled "Eutectic Lead Bisilicate Ceramic Composition and Fired Ceramic Bodies" or but in the US patent application, number not yet known (file number of the applicant FI 973 019) described by the applicant are.

The layered structure will be suitable for some time Treated pressure and suitable temperature and then sintered.

The lamination takes place at temperatures between approximately 80 ^° C. and 107 ^° C. at pressures between 56 and 91 kg / cm. These pressures are lower than the pressures normally used in conventional multilayer ceramic structures, which is a significant advantage of the present invention. Excessively high pressures can lead to separation of the laminate at the separating surfaces, undesired enclosing of the internal metallization and interlocking at the separating surface between ceramic and metal.

For a particular monolithic structure, of course, lamination is carried out until the desired bond is achieved is, and the exact duration of the laminxing process is not critical. For example, if you do the lamination for about 10 minutes carried out under the conditions given above, after having previously laminated at about half the pressure for 2 minutes, by about Driving out trapped air (the presence of which can damage the laminate) generally gives excellent results.

The sintering is generally ground on a refractory plate, which preferably consists of alumina or mullite, and is ground flat should be carried out, because the green, i.e. unfired ceramic foil is just as smooth as the plate and the fired The surface can only be as good as the surface of the unfired film or the laminate, and the curvature or curvature

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the fired foil will be no better than that of the unfired one Foil. In the case of sintered multilayer ceramic modules, a curvature of 0.004 mm / mm is still acceptable.

The dimensional tolerances must be maintained or adhered to in the fired state so that the sintered parts in mechanical devices suitable, e.g. for after sintering operations to be performed such as hard loosening of the connector pins and the like.

The stacked laminated structure of green foils is then placed on the refractory plate at temperatures between 825 to 925 ⁰ C. in an oxidizing or reducing atmosphere, for example in a wet gas, in hydrogen, air or the like in a continuous furnace on a nickel-chromium metal alloy sintered existing conveyor belt.

A major advantage of the present invention is that that oxidizing atmospheres are used during sintering, so that sintering can be carried out in a simple manner, compared to the greater difficulties in process control resulting from the use of reducing atmospheres ■ results. Accordingly, it is generally much preferable to carry out sintering in an oxidizing atmosphere.

The binder is generally in the temperature range! expelled from between room temperature and +500 ⁰ C, while the j Spxtzentemperaturen between about 825 and 925 ⁰ C, preferably from 875 to 925 ⁰ C, generally for 1 1/2 to 2 hours to: an optimum glass forming achieve be maintained.

j The throughput speed of the conveyor belt naturally depends on on the type of furnace used and should generally be set so that the binder is completely driven off and at the same time the top temperature for the required Duration is reached.

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A complete sintering cycle takes about 22 hours and ensures that the binder is completely driven off and is burned, although of course shorter or longer times, can be used depending on the type of binder, the proportion of binder and similar factors.

For use in circuitry for data processing equipment, the sintered parts should pass both the Zyglo color test for porosity and pass the water absorption test, from which it can be seen whether an optimal compression has been achieved.

The sintered ceramic compositions of matter according to FIG of the present invention, after sintering, has a density of from about 2.15 to about 2.35 g / cm, which values are generally are lower than in the prior art. This results in much lighter parts, which is an advantage is when the weight of the entire pack matters.

The composite, multilayer, ceramic structure can then after sintering with the otherwise usual general known further manufacturing processes are further processed.

The components for the production of the ceramic material according to the present invention will now be set out in detail, followed by some typical preferred types of glass.

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Typical composition of a batch

(1) Alumina for clay RO ₂ (a) Molecular formula ^R 2 ° 3 0.0008 SiO ₂ RO / R ₂ O 1.0000 Al ₃ O ₃ ■
0.0001 Fe ₃ O ₃ 0.0013 Na ₃ O
0.0012 MgO
0 _f 0005 CaO 0.0030

or - ^A1 2 ° 3 "101.94

(b) Molecular weight - 102.16

Wt% . 99.50 0.08 0.05 0.01

0.03 0.05

Cc) Oxides Mol% Al ₂ O ₃ 99.61 Na ₂ O 0.13 CaO 0.05 MgO 0.12 ^Fe 2 ° 3 0.01 SiO ₀ 0.08 Total 100.00 (d) density - 3.97 cm ³

99.73

Ce) particle size - <1.0 micron (f) particle shape - spherical

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(2) spodumene total for alpha spodumene 3 19.0 microns RO 2 , 86 (a) Molecular formula (d) Density - 2.77 cm ^R 2 ° 3 (e) Sieve Analysis - 92.2% on 200 mesh 1.13 m ² / g 4, 3203 SiO , 35 RO / R ₂ O (f) particle size - , 60 0.9284 Li ₂ O 1.0445 Al ₂ O ₃ (g) surface , 18 0.0226 Na ₂ O 0.0186 Fe ₀ O ₀ FI 973 018 , 10 0.0259 K ₂ O 0, 1391 H_0 , 35 0.0129 CaO , 73 0.0101 MgO , 20 0.9999 - Li _o 0-Al _o 0-4Si0 _o , 62 Theoretical formula - 401.64 Wt% , 99 (b) molecular weight Mol% 6th (c) oxides , 14.23 0 LiO ₂ 0.35 0 Na ₂ O 0.40 0 K ₂ O 0.20 0 CaO 0.15 26th MgO 16.06 0 Al ₂ O ₃ 0.29 64 Fe ₂ O ₃ 66.24 0 SiO ₂ 2.13 99 H ₀ O 100.05

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(3) wollastonite

(a) Molecular formula for wollastonite

^R 2 ° 3

0.0020

RO / R ₂ O

0.9863 CaO 0.0090 FeO 0.0017 MnO

0.0030 MgO 1.0000

(b) Molecular weight - 116.86

or
Theoretical formula - CaO.SiO,

(c) Oxides - MqI% CaO FeO MnO MgO

SiO ₂ TiO ₂

Total (d) density - 2.83 g / cm "

100.00 0.9995 SiO ₂ O, OOO7 TiO ₂ 0.0172 H ₂ O

Weight%

48.82 47.29 0.45 0.56 0.08 0.10 0.15 0.10 0.15 0.27 49.47 51.37 0.03 0.05 0.85 0.27

100.01

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(4) magnesium silicates

(a) Molecular formula for magnesium silicate

RO / R ₂ O MgO 0 ^R 2 ° 3 Ai ₂ O ₃ RO 2 SiO ₂ 0.9911 0 , 0231 ^Fe 2 ° 3 1r 2726 CaO , 0015 A ₂ O O _f OO89 O, 2838

1,000 (b) Molecular Weight - 123.58

(C)

Theoretical formula MgO.SiO ^ = 100.38 Weight% oxide Mol% 32.08 MgO 38.41 0.40 CaO 0.35 1.86 Al ₂ O ₃ 0.90 0.19 Fe ₂ O ₃ 0.06 61.35 SiO ₂ 49.32 4.09 HO 10.96

Total 100.00 99.97

(d) Particle size - 99.9% <15 microns

(e) Density - 2.67 g / cm ³

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(5) kyanite

(a) Molecular formula for H ₂ O Kyanite RO ₂ RO / R ₂ O R ₂ O ₃ 1.0422 SiO ₂ 0.0020 CaO 0.0012 MgO 1.0000 Al ₂ O ₃ 0.0025 Na ₂ O 0.0002 Fe ₂ O ₃ 0.0091 H ₀ O 0.0017 K _n O 0.0074 (b) Molecular Weight - 165.19 - 162.00 Theoretical formula - Al O ₃ .SiO ₂ GeW, -% (c) oxide Mol% 0.07 CaO 0.10 0.03 MgO 0.06 0.09 Na ₂ O 0.12 0.09 K ₂ O 0.08 61.40 Al ₂ O ₃ 48.57 0.15 Fe ₂ O ₃ 0.01 37.70 2 50.62 0.10 0.44

total

100.00

Theoretical kyranite - Al ₂ O ₃

(d) Density - 2.85 g / cnr

(e) Particle size - 8.6 microns

(f) surface area - 1.27 m ² / g

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99.63

O ₃ = 62.93 \ SiO ₂ = 37.07 \ total 100.00

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Typical preferred types of glass

Glasses in the interstitial area 1418
3891 ^R 2 ° 3 RO ₂ (T) molecular formula ^B 2 ° 3 ³ 20.6455 SiO ₂ RO / R ₂ O 0.6509 Li ₂ O
0.2309 K ₂ O 7,

0.1182 Na ₂ O 1.0000

(2) Molecular weight - 1817.54

Mol% wt%

2.23 1.07

0.79 1.20

0.41 0.40

0.49 0.80

25.33 28.31

70.76 68.22

Total 100.01 100.00

(3) Oxides Li ₂ O ^K 2 ° Na ₂ O Al ₂ O ₃ B ₂ O ₃ SiO ₂
I. (4) Amorphous (5) density

(6) Thermal expansion - 3.0 10 m / in / ° C.

(0-500 ⁰ C)

(7) Dielectric properties at 1 kHz and 25 ^° C

(a) Dielectric constant -4.2

(b) Power factor - 0.06

(c) Loss factor - 0.25

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Lithium tetraborate

(a) Molecular formula ^R 2 ° 3 Mol% RO / R ₂ O 2.0000 B ₃ O ₃ 32.81 Li ₂ O 0.0003 Fe ₂ O ₃ 65.63 - 170.06 0.01 (b) Molecular weight 1.55 or Li ₂ O.2B ₂ O ₃ - Theoretical Ref Oxides (C) Li ₂ O ^B 2 ° 3 Fe ₂ O ₃ ^H 2 °

0.04733

Total 100.00

(d) Density - 2.00 g / cm "

Wt% 17.57 81.90 0.03

0.48 99.98

(e) surface area - 2.33 πΓ / g

(f) Particle size 100 microns

Note: Lithium tetraborate is soluble in water. Ceramic bodies containing lithium tetraborate should be dry machined will.

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The exact composition of the ceramic body No. 1 to No. 7 is listed afterwards.

(1) Molecular Formula - No. 1 RO ₂ RO / R ₂ O R ₂ O ₃ 0.0648 Li ₂ O 3.2024 SiO ₂ 0.0248 K ₂ O 1 , 0000 Al ₃ O ₃ 0.0128 Na "O O , 7939 B ₀ O- 0.1074 (2) molecular weight - 354.77 Wt% (3) oxides Mol% 0.59 Li ₂ O 1.27 0.66 ^K 2 ° 0.49 0.22 Na ₂ O 0.25 28.73 Al ₂ O ₃ 19.61 15.58 ^B 2 ° 3 15.57 54.23 SiO ₂ 62.81

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Total 100.00 100.01

(1) Molecular Formula - No «2

RO / R ₂ O ^R 2 ° 3 RO ₂ 0.0500 Li ₂ O 0.0204 K ₂ O 1,000 Al ₃ O ₃ 0.0126 Na ₂ O 0.5672 B ₂ O ₃ 2.2144 SiO ₂ 0.0067 MgO 0.0011 ^ e ₃ O ₃ 0.0020 CaO 0.0917 (2) molecular weight - 279.11 (3) oxides ΜοΙ, -% GeW, -% Li ₂ O 1.29 0.55 κ ₂ ο 0.53 0.70 Na ₂ O 0.33 . 0.28 MgO 0.17 0.10 CaO 0.05 0.04 Al ₂ O ₃ 25.81 36.54 B ₂ O ₃ 14.64 14.15 Fe ₂ O ₃ 0.03 0.04 SiO 57.15 47.65

Total 100.00 100.05

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(1) Molecular Israel - No. 3

RO / R ₂ O R ₂ O ₃ 0.9334 Li ₂ O 0.0288 K ₂ O 0.0214 Na ₂ O 0.7501 0.0090 CaO 0.8200 0.0074 MgO 0.0132 1.0000 (2) molecular weight - 409.19 (3) oxides Mol% Li ₂ O 14.16 κ ₂ ο 0.44 Na ₂ O 0.32 CaO 0.14 MgO 0.11 Al ₂ O ₃ 11.38 B ₂ O ₃ 12.44 Fe ₂ O ₃ 0.20 SiO ₀ 60.81

RO

4.0090 SiO, wt%

6.82 0.66 0.33 0.12 0.07 1 8.69 1 3.95 0.52 58.84

total

100.00 100.00

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(1) Molecular Formula - ., '. HO. 4 -; - '... y Ro ₂ / BOZR ₂ O V ^R 2 ° 3 '4.7295 SlO ₂ 0.8469 CaO
0.0902 Li ₂ O 0.0322 K ₂ O r ~ v 1 j0082 Al ₃ O ₃ . 0.0005 TiO ₂ Ö> Ö177 Na ₂ O. ; ii
0.0077 FeO 1.0245 B ₃ O ₃ ■. ■■■ -. ■ 0.0041 MgO 0.0014 MnO ■ '- ■ ^: -' ^: "- '"' ■■■■ - "'" ■ " 1,0002 (2) "" molecular weight «513.35 Wt% (3) oxides Mol% 9.26 : GaO , 10.93 0.11 ; -:; ..? ^e0 «: ., 0.11 _; _. . 0.02 ,% MnO , 0.03 0.03 's.MgO .- · ,. 0.06

te ν. J4J

^B 2 ° 3

TiO,

total

a _Ä : 0.24 K ₁ - 0.42

- && .- .. ^{1 '18} ? 0, co: i 2.99

13.19 60.84

0.01 100.00

0.21

..? 0.59

C 0.52

20.02

13.90

55.31

0.01 99.98

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(1) Molecular Formula - No. 5

RO / R ₂ O 0.8371 MgO 1 R. & ό ο, RO ₂ SiO ₀ 0.1130 Li "0 i 0 6548 0.0394 ^K 2 ° , 0730 Al ₂ O ^Η 2 ° 0.0079 CaO , 2811 ^Β 2 ° 3 0.0026 Na ₂ O , 0011 Pe ₂ O ₃ 2386

1.0000

(2) Molecular weight - 519.38

(3) oxides MoI -% MgO 10.45 Li ₂ O 1.41 κ ₂ ο 0.49 CaO 0.10 Na ₂ O 0.03 ^A1 2 ° 3 13.40 ^B 2 ° 3 15.99 ^Fe 2 ° 3 0.01 SiO, 58.11

total

99.99 wt%

6.50

0.65

0.71

0.08

0.03 21.06 17.18

0.03

53.83 100.07

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(1) Molecular Formula - No.

^R 2 ° 3

0.4185 MgO 0.4077 CaO 0.1096 Li ₂ O 0.0387 K ₂ O 0.0214 Na ₂ O 0.0036 EeO

0.0005 MnO ^: 1.0000

(2) Molecular Weight - 504.25 1.0285 ₂₃
1.2421 B ₂ O ₃
0.0005 Fe ₃ O ₃

(3) oxides Mole% MgO 5.45 CaO 5.31 Li ₂ O 1.43 K ₂ O 0.50 Na ₂ O 0.28 FeO 0.05 MnO 0.00 Al ₂ O ₃ 13.40 ^B 2 ° 3 16.18 Fe ₂ O ₃ 0.00 SiO ₂ 56.36 2 0.00

RO,

4.4037 SiO ₂

0.0005 TiO ₂

total

98.96 wt% 3.35 4.53 0.65 0.72 0.26 0.05 0.01

20.80

17.15 0.02

52.45

0.01

100.00

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(1) Molecular Formula - No. 7th

RO / R ₂ O ^R 2 ° 3 Al ₂ O ₃ RO ₂ 0.2952 Li ₂ O ^B 2 ° 3 0.0293 K ₂ O ^Fe 2 ° 3 3.8580 SiO ₂ 0.3426 CaO 0.6753 0.3233 MgO O _f 7361 0.0060 Well _? 0 0.0052 0.0032 FeO 0.0004 TiO ₂ 0.0004 MnO 1.0000 (2) molecular weight - 396.82 (3) oxides MoI .- * Wt% Li ₂ O 4.70 2.22 K ₂ O 0.47 0.70 CaO 5.45 3.48 MgO 5.15 4.57 Na ₂ O 0.10 O, O9 FeO 0.05 0.06 MnO 0.01 0.02 Al ₂ O ₃ 10.76 17.34 ^B 2 ° 3 11.73 12.92 Fe ₂ O ₃ 0.08 0.21 SiO ₂ 61.48 58.39 TiO 0.01 0.02

total

99.99

100.02

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The ceramic bodies No. 1 to No. 7 became from the above Compositions of the batches and types of glass produced according to the following table:

Batch composition for ceramic bodies No.1 No.2 No.3 No.4 No ^ 5 No.6 No.7

Calcined
Kyanite 45.0

Mullite 50.0

Spodumene 70, O 25 _f O ]

Wollastonite 22.22 10.0 10.0 >

Alumina 22.22 20.0 20.0 10.0 j

Magnesium j

silicate 20.0 10.0 10.0 ^!

Lithium-

tetraborate 10.0

Glass No.1 55, O 50.0 20.0 55.55 60.0 60.0 45.0
Total 100.00 100.0 100.0 99.99 100.0 100.0 100.0

^FI973018 509837/0794

The following examples are intended to be preferred embodiments of the invention:

The batch combination for a ceramic body no. 1 ibis No. 7 were made from the composition of the substance as specified in has been described above, prepared and in a ball mill with the following binder mixture for preparation ground to a spreadable or pourable raw mass.

Organic components of the raw mass (binder composition

Wt%

polymethyl methacrylate bioctyl phthalate

iMethylene chloride

berchloroaethyleri

total

11 26th 11 26th 41, 78 35 , 70

Note:

100.00

Weight (g) specific weight 39 _# β0 0.972 39.60 0.970 146.86 0.991 125.50 1.62272 351.56

(a) The ratio of the weights between ceramic matrix and binder was 1.14 s 1.0

(b) Specific gravity = 1.70

(c) Volume concentration of pigment - 65.91%

(d) Weight concentration of pigment = 83.47 %

(e) Viscosity at 25 ⁰ C at 20 revolutions / min - 1100 cps'

at 50 revolutions / min - 1500 cps

(f) Particle size distribution between 0 and 12.7x10 ram

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After pouring and drying at room temperature to drive off the solvent, the green foils (the thickness after drying is 0.2 10 mm + 0.000013 mm) are punched out into rectangles of 76.2 χ 127 mm and reference holes for exact stacking and creates the mechanical alignment in the foils. ¹

Ten such foils were stacked on top of one another and at a pressure of 45.5 kg / cm and a temperature of about 80 ⁰ C for

2 ■

2 min and then laminated at 91 kg / cm at the same temperature of about 80 ^° C. for 10 min.

This so-called green composite structure was then cut to the final dimensions of approximately 50 χ 50 mm (taking into account the linear shrinkage), placed on a refractory plate and in air in a continuous furnace sintered under the following conditions!

The temperature was increased for 18 hours at constant speed from room temperature to the final sintering temperature of 900 + 25 ⁰ C (burning out the \ binder was completed at 600 ⁰ C substantially.

; Final sintering for 2 hours at the sintering temperature of 895 + 25 ⁰ C.

The sintered body was then passed through a cooling zone in the continuous furnace and out of the furnace at room temperature taken. The results of the product analysis are presented in the table below. For the sake of simplicity, none were continuous Drilled holes made and no metallization made.

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Electro-ceramic properties of the ceramic bodies (sintered blanks)

Features No.1 No.2 No.3 No.4 No.5 No.6 No.7

Color brown pink elven pink white pink light

leg brown

Surface 22 20 15 15 12 12

Porosity not porous

i water absorption

; _tloa zero percent

; Curvature 0.004 mm / mm

! Shrinkage 13.90 15.1 4.9 11.9 19.0 11.25 5.28

! Density 2.00 2.28 1.93 2.23 2.05 2.28 2.00

stretched ³³ '° ⁴⁰ ' ° ¹⁷ '° ⁴⁵ ' ° ^{46 40} '° ⁴³ ' °

Thermal conductivity _{n ni n}

ability ° ^'01 °'

^{17f0 20 # 0 13} '° ²⁶ ' ° ^2O '° ²² ' ° ²⁵ '°

60,000 V / o »

Loss factor 0.0040 0.0020 0.0080 0.0055 0.0023 0.0025 0.0054

FI 973

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Note:

(a) Linear shrinkage in%

(b) Density in g / cm

(c) Thermal expansion 25 to 450 ° C, e.g. 33.0 χ 10 ~ ⁷ cm / cm / ° C

(d) thermal conductivity

e.g. 0.008 cal cm / sec cm ⁰ C.

(e) Dielectric strength, e.g., 60,000 V / cm

(f) Dielectric measurements at 25 ⁰ C and 1 kHz frequency

(g) Flexural Strength

2 e.g. 1190 kg / cm

Fi 973 018 609837/0794

Claims (3)

PATENT CLAIMS 1. Sintered _t ceramic body made from a ceramic : Substance composition with a low dielectric constant ; stante, characterized in that it consists of a poly- ! crystalline, ceramic, refractory material and ; consists of a glass arranged in the intermediate grid area * ! 2. A ceramic body according to claim 1, characterized gekennzeich- \ net that disposed in the interstitial area glass ! about 25 to 65% by weight of the weight of the refractory may terials including the glass arranged in the interstitial lattice area. , 3. Ceramic body according to claim 1, characterized in-I net that the glass j arranged in the swashplate area is about 35 to 50% of the weight of the refractory material: including the glass arranged in the interstitial area. ! 4 * ceramic body according to claim 1, characterized marked, ] net that the refractory material has a dielectric constant of about 6 to about 9. ; 5. Ceramic body according to claim 4, characterized in that the body has a dielectric constant of i is from about 4.3 to about 6.2. 6. Sintered ceramic body of low dielectric constant according to claim 1, characterized in that the refractory material is an acidic material. 7. Sintered ceramic body with low dielectric Factor constant according to Claim 1, characterized in that the refractory material is a neutral substance. FI 973 018 509837/0794 8. Sintered ceramic body with low dielectric constant according to claim 1, characterized in that the refractory material is a basic substance. 9. Ceramic body according to claim 1 to 8, characterized in that that the glass lying in the interstitial region has a coefficient of thermal expansion of less than 5.0 10 ~ ⁶ cm / cm / ° C. 10. Ceramic body according to claim 1 to 9, characterized in that that the glass arranged in the interstitial region is selected from a group consisting of borosilicate and Contains aluminum borosilicate glasses. 11. Ceramic body according to claim 1 to 10, characterized in that that the glass arranged in the interstitial region has a dielectric constant of less than about 5.0. 12. Low dielectric constant sintered ceramic body according to claim 1, characterized in that the refractory material is selected from one group containing clay, spodumene, wollastonite, magnesium silicate, kyanite or mixtures thereof. 13. Ceramic body according to claim T to 12, characterized in that the glass arranged in the interstitial region is about 25 to 65% by weight of the total weight of the refractory material including the glass, that the body has a dielectric constant of about 4.5 to about 6 , 2 has that the glass lying in the interstitial region has a coefficient of thermal expansion of about 3.3 to about 4.5 χ 10 ~ ⁶ cm / cm / ° C and a dielectric constant of about 4.1 to about 4.2 and that the refractory Material has a dielectric constant of about 6.0 to 9.0. Fi 973 018 50983 7/07 9 4 14. Application of a sintered, ceramic body with low dielectric constant on multilayer, ceramic structures of electrical switching elements such that at least one of the layers of the sintered low dielectric constant ceramic material made of polycrystalline, ceramic ", refractory Material and a glass arranged in the interstitial area «, PI 973 018 509837/0794