Multilayer glass ceramic substrate and process for producing the same

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multilayer glass ceramic substrate used for high density implementation of LSI elements and more specifically to a multilayer glass ceramic substrate which can be sintered at low temperatures and to a process for producing the same.
2. Description of the Related Arts
Development of semiconductor technology require down-sizing and high-speed of electronics devices and systems. In fact, as the semiconductor elements are integrated into VLSI and ULSI of high density, very high density and fine-processing ale required in the implementation technique for assembling the elements. In particular, it is requested to increase the wiring density of the substrate on which semiconductor elements are implemented so as to comply with finer pattering and higher operation speed and to lower the dielectric constant of substrate materials.
Alumina multilayer substrate has been used widely. This substrate is produced by a thick film printed multilayer technique or a green sheet lamination technique. The latter technique is more advantageous so as to satisfy requirement of high-density integration. In the green sheet lamination technique, a plurality of thin ceramic green sheets each on which wiring lines are printed are laminated before integrated, so that it is easy to increase the wiring layers to a desired number and hence the wiring density can be increased comparing to the thick film printed multilayer technique.
Alumina ceramic, however, has such a demerit that sintering must be carried out above 1,500.degree. C. which require to use, as wiring conductor, Mo, W metal having a relatively high electric resistance and hence it is difficult to realize fine wiring. Still more, the dielectric constant of alumina is about 10 which is too high for high-speed operation of signals.
Recently, ceramic materials which can be sintered at relatively lower temperatures have been developed so that low resistance conductors such as Au, Ag--Pd, Ag or Cu can be used. For example, a composite material consisting of alumina and borosilicate lead glass can be sintered at a low temperature below 1,000.degree. C. to produce a multilayer substrate in which Au, Ag--Pd or Ag can be used as a wiring conductor. However, in this composite material, it is difficult to use wiring of Cu which is a base metal because the composite material contains lead and hence sintering can not be carried out in a reduction atmosphere. Still more, the electric constant of this composite material can not be lowered below 7.5.
Glass ceramic material using borosilicate glass is also know. This glass ceramic material can be sintered at a temperature lower than 1,000.degree. C. in a reduction atmosphere and has lower dielectric constant of about 5.5, so that a multilayered structure having wiring lines of Cu can be realized simultaneously at the sintering of glass ceramic. Known glass ceramic material, however, possess very poor mechanical strength because no crystallization occur by the sintering.
The mechanical strength is a very important factor of the substrate. In fact, in the case of a multi-chip implementation substrate on which a large number of semiconductor elements are implemented, the substrate size increases and input/output terminals or pins are connected at different levels, if the he mechanical strength of the substrate is poor, problems of breakage of the substrate, junction failure or the like occur in assembly stage and on a product.
An object of the present invention is to resolve the problems of conventional implementation substrate and to provide a multilayer glass ceramic substrate which can be sintered at a low temperature below 1,000.degree. C. in neutral and reduction atmosphere in addition to oxidation atmosphere and which has a low dielectric constant and improved mechanical strength.
The multilayer glass ceramic substrate according to the present invention can be used as an implementation substrate for high-density fine-wiring and high speed, since low resistance metals such as Au, Ag, Cu, Ag--Pd or the like can be used as wiring conductor.
SUMMARY OF THE INVENTION
The present invention provides a multilayer glass ceramic substrate having a plurality of conductor layers each laminated through a glass ceramic layer, characterized in that the glass ceramic layer has a composition comprising of alumuina, borosilicate magnesium glass and cordierite crystal produced by chemical reaction between alumina and borosilicate magnesium glass, the content of alumina being 12 to 59.6 wt %, the content of borosilicate magnesium glass being 18 to 69.6 wt % and the content of the cordierite crystal being 1 to 50 wt %, the sum of components being 100 wt %.
The composition can contain a forth component selected from a group consisting of silica glass, .alpha.-quartz and mullite. The content of the forth component is 10 to 30 wt %, the sum of components being 100 wt %.
The present invention provides also a process for producing a multilayer glass ceramic substrate by the steps of mixing material powders, preparing green sheets from slurry of the mixed material powders, forming via halls in the green sheets, printing wiring conductors on the green sheets and filling the via halls with conductor, laminating a plurality printed sheets, compressing the laminated sheets under heat and then sintering compressed sheets at a temperature below 1,000.degree. C., characterized in that the mixed material powders consists of 30 to 60 wt % of alumina powder and 70 to 40 wt % of borosilicate magnesium glass powder.
In the process according to the present invention, cordierite crystals are produce when alumina powder and borosilicate magnesium glass powder are sintered.
Alumina powder has preferably the average particle size of 0.5 to 3 .mu.m and borosilicate magnesium glass powder has preferably the average particle size of 1 to 5 .mu.m.
In a variation of the process according to the present invention, a third powder selected from a group consisting of silica glass, .alpha.-quartz and mullite is added to the material powders in such proportions as 10 to 50 wt % of alumina powder, 40 to 70 wt % of borosilicate magnesium glass powder and 10 to 50 wt % of the third powder, the sum of all powders being 100 wt %.
The third powder has preferably the average particle size of 0.5 to 10 .mu.m.
The content of magnesium in the borosilicite magnesium glass is preferably more than 5 wt % in term of magnesium oxide.
In the process according to the present invention, the material powders or green sheets are sintered below 1,000.degree. C. to produce a multilayer glass ceramic substrate having improved properties because of following reason. In the sintering, borosilicate magnesium glass start to be softened at about 700.degree. C. The resulting liquidized glass penetrate into and fill in spaces or clearances among ceramic powders of alumina, among ceramic powders of alumina and cordierite crystals and among ceramic powders of alumina, cordierite crystals and quart glass, .alpha.-quartz or mullite to produce packed structure and a completely compacted glass ceramic body is formed finally at a temperature range form 800.degree. to 1,000.degree. C.
The material powders or green sheets of the present invention can be sintered in a reduction atmosphere because the material powders of the present invention do not contain such elements that is reduced to elemental metal from oxide under the sintering condition. To the contrary, in the case of known material powders containing for example lead oxide, lead oxide is converted, in the reduction atmosphere, to metal lead which seriously deteriorate the insulation property of the resulting glass ceramic body obtained.
The multilayer glass ceramic substrate according to the present invention possesses improved mechanical strength which is one of very important properties required in implementation of semiconductor elements. Usually, the bending strength of higher than 2,000 kg/cm.sup.2 is required in the substrate for implementing semiconductor elements. The multilayer glass ceramic substrate according to the present invention satisfies this strength because a compacted fine structure is realized by the sintering. In fact, the reaction between alumuina and liquidized glass produces the cordierite crystal, so that the resulting glass ceramic obtained by the sintering possess a fine strong structure in which particles of alumina, particles of cordierite crystal (and also particles of silica glass, .alpha.-quartz or mullite, if they exist) and glassy mass are bonded three-dimensionially and which has all improved bending strength.
In the process according to the present invention, sintering can be effected below 1,000.degree. C., the multilayer structure can be easily realized by the green sheet lamination technique and any conductor including basic metals such as Cu, Ni, their alloys or those that must be sintered in neutral or reduction atmosphere in addition to noble metals of Au, Ag, Pd, Pt or the like can be used.
The multilayer glass ceramic substrate according to the present invention possesses improved mechanical strength or bending strength of higher than 2,000 kg/cm.sup.2 and low, dielectric constant and makes it possible to realize fine wiring with high implementation density.

DESCRIPTION OF THE PREFERRED EMBODIMENT
Now, Examples of the present invention is explained but the present invention is not limited to the Examples.
EXAMPLE 1
(Alumina+borosilicate magnesium glass)
As material powders alumina powder and borosilicate magnesium glass powder were used.
Alumina powder having the average particle size of 0.5 .mu.m to 3 .mu.m and borosilicate magnesium glass powder having the average particle size of 1 to 5 .mu.m were intimately mixed at a proportion range from 30 wt % 70 wt % to 60 wt %:40 wt %.
Borosilicate magnesium glass used have following composition by weight:
______________________________________B.sub.2 O.sub.5 15 CaO 1SiO.sub.2 65 BaO 1MgO 12 TiO.sub.2 1Na.sub.2 O 2 ZrO.sub.2 1K.sub.2 O 2______________________________________
The resulting mixed material powder was dispersed together with an organic binder of polyvinyl butyral, polyvinyl alcohol or polyacrylic resin in a solvent to prepare a slurry from which a green sheet was molded by slip casting technique. The thickness of the green sheet was adjusted in a range from 10 to 400 .mu.m.
Then, via halls connecting upper and lower conductors were formed in the green sheet bit a punching machine. A wiring pattern was printed by screen printing technique with conductor past and the via halls were filled with the conductor past. The conductor past used consisted mainly of Au, Ag, Ag--Pd, Cu, Ni or Ag--Pt.
Predetermined numbers of green sleets each on which the conductor pattern was printed and of which the via hall was filled were laminated and compacted under heat. Then, the laminated green sheets were heated to a temperature of 400.degree. to 700.degree. C. to remove the organic binder and the solvent (elimination of bindery).
Finally, the laminated green sheets were sintered at a temperature ranging form 800.degree. to 1,000.degree. C. to obtain a multilayer glass ceramic substrate. During this sintering stage, the cordierite crystal is produced by a chemical reaction between alumina and borosilicate magnesium glass and the softened glass mass penetrate into and fill spaces or clearances among particles so as to promote compacted structure.
Composition of glass ceramic layer of sintered substrates obtained are summarized in Table 1. The composition bias determined bar usual X-ray diffraction method. The contents of alumina and cordierite crystal which are determined by comparing their peaks to a peak of silicon used as a reference and a proportion of borosilicate magnesium glass is calculated by subtracting their contents from the total.
Conductor, sintering conditions, numbers of layers and wiring specification used for manufacturing multilayer glass ceramic substrates as well as the results obtained are summarized in Tables 2 and 3. The sample numbers in Table 1 correspond to those in Tables 2 and 3.
TABLE 1______________________________________Alumina + borosilicate magnesium glass Composition ratio (wt %)Sample Borosilicate CordieriteNumber Alumina glass crystal______________________________________1 12 38 502 12 43 453 12 48 404 17.4 32.6 505 18.1 37.6 44.36 18.2 50.1 31.77 22.0 29.1 48.98 23.2 39.5 37.39 23.3 48.7 28.010 23.5 57.3 19.211 27.9 29.8 42.312 28.1 41.0 30.913 28.1 50.5 21.414 28.3 61.8 9.915 33.2 18.9 47.816 33.3 31.6 35.117 33.3 35.3 31.418 33.5 46.9 19.619 38.4 27.7 33.920 38.4 31.4 30.221 38.7 34.7 26.622 38.8 50.7 10.523 42.0 18.0 4024 42.1 33.8 24.125 42.1 37.3 20.626 42.3 43.2 14.527 46.3 38.2 15.528 46.3 43.7 10.029 48.4 18.0 33.630 48.6 20.9 30.531 48.7 29.8 21.532 48.7 35.2 16.133 52.5 21.8 25.734 52.5 27.4 20.135 52.6 30.3 17.136 52.8 34.1 13.137 56.1 29.8 14.138 56.3 33.7 1039 56.3 38.5 5.240 56.5 42.5 1.0______________________________________
TABLE 2__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm) 1 900 Ag Air 30 120 300 150 5.4 40 2200 >10.sup.13 2 900 Ag Air 30 120 300 150 5.3 41 2300 >10.sup.13 3 910 Ag--Pd Air 30 120 300 150 5.2 43 2300 >10.sup.13 4 880 Cu N.sub.2 30 120 250 120 5.5 40 2200 >10.sup.13 5 850 Cu N.sub.2 30 120 250 120 5.5 43 2300 >10.sup.13 6 850 Cu N.sub.2 30 120 250 120 5.1 46 2600 >10.sup.13 7 900 Cu N.sub.2 + H.sub.2 40 150 300 150 5.8 40 2300 >10.sup.13 8 910 Cu N.sub.2 + H.sub.2 40 150 300 150 5.6 44 2300 >10.sup.13 9 900 Ag Air 40 150 300 150 5.3 48 2400 >10.sup.1310 900 Ag Air 40 150 300 150 5.0 49 2600 >10.sup.1311 890 Ag Air 40 150 300 200 5.8 43 2700 >10.sup.1312 880 Ag Air 40 150 300 200 5.6 47 2500 >10.sup.1313 900 Ag--Pd Air 40 150 300 200 5.5 49 2400 >10.sup.1314 880 Ag--Pd Air 30 150 300 200 5.2 52 2600 >10.sup.1315 880 Ag--Pd Air 30 100 200 100 6.5 41 2600 >10.sup.1316 900 Ag--Pd Air 30 100 200 100 6.2 45 2400 >10.sup.1317 870 Ag Air 30 100 250 120 6.2 46 2500 >10.sup.1318 850 Ag Air 30 100 250 120 6.0 49 2500 >10.sup.1319 890 Ag Air 30 100 250 120 6.2 47 2700 >10.sup.1320 900 Ag Air 35 100 300 150 6.1 47 2500 >10.sup.13__________________________________________________________________________
TABLE 3__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)21 900 Cu N.sub.2 35 100 300 150 6.1 43 2500 >10.sup.1322 850 Cu N.sub.2 35 100 300 150 5.8 48 2800 >10.sup.1323 930 Cu N.sub.2 35 100 300 150 6.8 39 2400 >10.sup.1324 900 Cu N.sub.2 40 150 300 150 6.1 45 2500 >10.sup.1325 910 Cu N.sub.2 + H.sub.2 40 150 350 150 5.9 48 2500 >10.sup.1326 900 Au Air 40 150 350 150 5.8 50 2600 >10.sup.1327 900 Ag Air 40 150 250 150 5.8 51 2700 >10.sup.1328 880 Cu N.sub.2 40 150 250 150 6.2 53 2800 >10.sup.1329 950 Cu N.sub.2 40 120 300 120 6.7 45 2500 >10.sup.1330 930 Ag--Pd Air 30 120 300 120 6.6 47 2500 >10.sup.1331 900 Ag--Pd Air 30 120 300 120 6.4 49 2400 >10.sup.1332 900 Au Air 30 120 300 120 6.2 51 2300 >10.sup.1333 930 Cu N.sub.2 30 120 250 100 6.7 48 2400 >10.sup.1334 910 Cu N.sub.2 30 120 250 100 6.5 50 2400 >10.sup.1335 950 Ag--Pd Air 30 120 250 100 6.4 51 2300 >10.sup.1336 950 Ag--Pd Air 30 100 200 80 6.4 51 2300 >10.sup.1337 930 Ag--Pd Air 40 100 250 120 6.7 50 2400 >10.sup.1338 960 Ag--Pd Air 40 100 250 120 6.5 52 2300 >10.sup.1339 900 Ag Air 40 100 250 120 6.4 54 2200 >10.sup.1340 900 Cu N.sub.2 40 80 200 80 6.5 55 2100 >10.sup.13__________________________________________________________________________ 1
Tables 2 and 3 reveal such facts that multilayer glass ceramic substrates having the compositions according to the present invention shown in Table 1 posses improved properties required in practical uses including satisfactory mechanical strength and that fine wiring of high-density can made easily.
On the contrary, when the content of alumina is less than 12 wt %, the bending strength of substrate become lower than 2,000 kg/cm.sup.2 and is insufficient. If the alumina content exceed 59.6 wt %, sintering can not be carried out below 1,000.degree. C. so that the insulation resistance decrease and that the bending strength become lower than 2,000 kg/cm.sup.2 and the dielectric constant becomes higher than 7, which is disadvantageous for high-speed circuits. In these cases, practical multilayer glass ceramic substrate can not be produced.
When the content of borosilicate magnesium glass is not higher than 18 wt %, it is impossible to obtain a glass phase sufficient to fill spaces or clearances among alumina particles, so that the strength become lower and the reliability can not be expected. It the content of borosilicate magnesium glass exceed 69.6 wt %, the strength intrinsic to class dominates so that the bending strength become less than 2,000 kg/cm.sup.2.
If the content of the cordierite crystal is less then 1 wt %, the effect for reinforcing the strength obtained by the presence of cordierite crystals can not be expected so that it is impossible to obtain the bending strength of more than 2,000 kg/cm.sup.2. If the content of the cordierite crystal exceed 50 wt %, the multilayer glass ceramic substrate does not shrink uniformly and hence the reliability is lost.
If the content of magnesium in the borosilicate magnesium glass used as a material powder becomes less than 5 wt % in term of magnesium oxide, no or little cordierite crystal is produced by sintering, operation.
If the particle size of alumina powder used becomes lower than 0.5 .mu.m or higher than 3 .mu.m, and if the particle size of borosilicate magnesium glass powder become lower than 1 .mu.m or higher than 5 .mu.m, the mixed material powder can not be sintered satisfactorily, so that the resulting multilayer glass ceramic substrate shows very poor reliability and hence can not be used in practical uses.
EXAMPLE 2
(Alumina+borosilicate magnesium glass+silica glass)
Example 1 is repeated except silica glass was added to the material powders of alumina powder and borosilicate magnesium glass powder.
Namely, alumina powder having the average particle size of 0.5 .mu.m to 3 .mu.m, borosilicate magnesium glass powder having the average particle size of 1 to 5 .mu.m and silica glass powder having the average particle size of 0.5 .mu.m to 10 .mu.m were intimately mixed at a proportion of (alumina+silica glass):borosilicate magnesium glass of front 30 wt %:70 wt % to 60 wt %:40 wt %. The proportion of alumina powder was adjusted above 10 wt %.
Composition of glass ceramic layer of sintered substrates obtained are summarized in Table 4 and conductor, sintering conditions, numbers of layers and wiring specification used for manufacturing multilayer glass ceramic substrates as well as the results obtained are summarized in Tables 5 and 6. The sample numbers in Table 4 correspond to those in Tables 5 and 6.
TABLE 4______________________________________Alumina + borosilicate magnesium glass + silica glassComposition ratio (wt %)Sample Borosilicate type CordieriteNumber Alumina Silica glass Glass crystal______________________________________101 12.0 21.0 37.0 30.0102 12.0 30.0 33.0 25.0103 12.4 11.0 69.6 20.0104 17.0 25.0 32.0 26.0105 17.0 10.0 23.0 50.0106 18.0 21.0 40.0 21.0107 22.0 18.0 25.0 35.0108 23.0 15.0 27.0 35.0109 23.0 19.0 38.0 20.0110 23.0 24.0 20.0 33.0111 28.0 20.0 19.0 33.0112 28.0 11.0 51.0 10.0113 28.0 17.0 40.0 15.0114 28.0 17.0 35.0 20.0115 33.0 17.0 36.0 14.0116 33.0 12.0 25.0 30.0117 33.0 18.0 20.0 29.0118 34.0 10.0 45.0 11.0119 38.0 19.0 18.0 25.0120 38.0 24.0 24.0 14.0121 39.0 15.0 28.0 18.0122 39.0 11.0 40.0 10.0123 42.0 11.0 18.0 29.0124 42.0 12.0 28.0 18.0125 42.0 10.0 30.0 18.0126 42.5 13.0 34.5 10.0127 46.0 10.0 31.0 23.0128 46.0 11.0 33.0 10.0129 48.0 11.0 18.0 23.0130 48.0 12.0 21.0 19.0131 49.0 10.0 21.0 20.0132 49.0 15.0 26.0 10.0133 52.0 12.0 18.0 18.0134 52.0 12.0 20.0 16.0135 53.0 11.0 22.0 14.0136 53.0 11.0 24.0 12.0137 56.0 10.0 25.0 9.0138 56.0 10.0 21.0 13.0139 57.0 10.0 24.0 9.0140 59.6 10.0 19.4 11.0______________________________________
TABLE 5__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)101 900 Ag Air 30 120 300 150 5.0 40 2200 >10.sup.13102 900 Ag Air 30 120 300 150 4.9 41 2300 >10.sup.13103 910 Ag--Pd Air 30 120 300 150 4.8 43 2300 >10.sup.13104 880 Cu N.sub.2 30 120 250 120 5.1 40 2200 >10.sup.13105 850 Cu N.sub.2 30 120 250 120 5.5 43 2300 >10.sup.13106 850 Cu N.sub.2 30 120 250 120 4.7 46 2600 >10.sup.13107 900 Cu N.sub.2 + H.sub.2 40 150 300 150 5.4 40 2300 >10.sup.13108 910 Cu N.sub.2 + H.sub.2 40 150 300 150 5.2 44 2300 >10.sup.13109 900 Ag Air 40 150 300 150 4.9 48 2400 >10.sup.13110 900 Ag Air 40 150 300 150 4.6 49 2600 >10.sup.13111 890 Ag Air 40 150 300 200 5.4 43 2700 >10.sup.13112 880 Ag Air 40 150 300 200 5.2 47 2500 >10.sup.13113 900 Ag--Pd Air 40 150 300 200 5.1 49 2400 >10.sup.13114 880 Ag--Pd Air 30 150 300 200 4.8 52 2600 >10.sup.13115 880 Ag--Pd Air 30 100 200 100 6.1 41 2600 >10.sup.13116 900 Ag--Pd Air 30 100 200 100 5.8 45 2400 >10.sup.13117 870 Ag Air 30 100 250 120 5.8 46 2500 >10.sup.13118 850 Ag Air 30 100 250 120 5.6 49 2500 >10.sup.13119 890 Ag Air 30 100 250 120 5.8 47 2700 >10.sup.13120 900 Ag Air 35 100 300 150 5.7 47 2500 >10.sup.13__________________________________________________________________________
TABLE 6__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)121 900 Cu N.sub.2 35 100 300 150 5.7 43 2500 >10.sup.13122 850 Cu N.sub.2 35 100 300 150 5.4 48 2800 >10.sup.13123 930 Cu N.sub.2 35 100 300 150 6.4 39 2400 >10.sup.13124 900 Cu N.sub.2 40 150 300 150 5.7 45 2500 >10.sup.13125 910 Cu N.sub.2 + H.sub.2 40 150 350 150 5.5 48 2500 >10.sup.13126 900 Au Air 40 150 350 150 5.4 50 2600 >10.sup.13127 900 Ag Air 40 150 250 150 5.4 51 2700 >10.sup.13128 880 Cu N.sub.2 40 150 250 150 5.8 53 2800 >10.sup.13129 950 Cu N.sub.2 40 120 300 120 6.3 45 2500 >10.sup.13130 930 Ag--Pd Air 30 120 300 120 6.2 47 2500 >10.sup.13131 900 Ag--Pd Air 30 120 300 120 6.0 49 2400 >10.sup.13132 900 Au Air 30 120 300 120 5.8 51 2300 >10.sup.13133 930 Cu N.sub.2 30 120 250 100 6.3 48 2400 >10.sup.13134 910 Cu N.sub.2 30 120 250 100 6.1 50 2400 >10.sup.13135 950 Ag--Pd Air 30 120 250 100 6.0 51 2300 >10.sup.13136 950 Ag--Pd Air 30 100 200 80 6.0 51 2300 >10.sup.13137 930 Ag--Pd Air 40 100 250 120 6.3 50 2400 >10.sup.13138 960 Ag--Pd Air 40 100 250 120 6.1 52 2300 >10.sup.13139 900 Ag Air 40 100 250 120 6.0 54 2200 >10.sup.13140 900 Cu N.sub.2 40 80 200 80 6.1 55 2100 >10.sup.13__________________________________________________________________________
When the content of silica glass powder is less than 10 wt %, the dielectric constant become higher than 7. On the other hand, if the content of silica glass powder exceed 30 wt %, satisfactory sintering can not be carried out so that the insulation resistance becomes lower and the bending strength become lower than 2,000 kg/cm.sup.2.
When the particle size of alumina powder used becomes lower than 0.5 .mu.m or higher than 3 .mu.m, the particle size of borosilicate magnesium glass powder become lower than 1 .mu.m or higher than 5 .mu.m and the particle size of silica glass powder become lower than 0.5 .mu.m or higher than 10 .mu.m, the mixed material powder can not be sintered satisfactorily, so that the resulting multilayer glass ceramic substrate shows very poor reliability and hence can not be used in practical uses.
By the same reason as Example 1, practical multilayer glass ceramic substrate can not be obtained outside the proportions according to the present invention (12 to 59.6 wt % of alumina, 18 to 69.6 wt % of borosilicate magnesium glass and higher than 1 wt % of cordierite crystal).
By the same reason as Example 1, if the content of magnesium in the borosilicate magnesium glass used becomes less than 5 wt % in term of magnesium oxide, no or little cordierite crystal is produced by sintering operation.
EXAMPLE 3
(Alumina+borosilicate magnesium glass+mullite)
Example 2 is repeated except silica glass was replaced by mullite powder.
Namely, alumina powder, borosilicate magnesium glass powder and mullite powder having the average particle size of 0.5 .mu.m to 10 .mu.m were intimately mixed at a proportion) of (alumina+mullite): borosilicate magnesium glass of from 30 wt %:70 wt % to 60 wt %:40 wt %. The proportion of alumina powder was adjusted above 10 wt %.
Composition of glass ceramic layer of sintered substrates obtained are summarized in Table 7 and conductor, sintering conditions, numbers of layers and wiring specification used for manufacturing multilayer glass ceramic substrates as well as the results obtained are summarized in Tables 8 and 9. The sample numbers in Table 7 correspond to those in Tables 8 and 9.
TABLE 7______________________________________Alumina + borosilicate magnesium glass + mulliteComposition ratio (wt %)Sample Borosilicate type CordieriteNumber Alumina Mullite Glass crystal______________________________________201 12.0 21.0 37.0 30.0202 12.0 30.0 33.0 25.0203 12.4 11.0 69.6 20.0204 17.0 25.0 32.0 26.0205 17.0 10.0 23.0 50.0206 18.0 21.0 40.0 21.0207 22.0 18.0 25.0 35.0208 23.0 15.0 27.0 35.0209 23.0 19.0 38.0 20.0210 23.0 24.0 20.0 33.0211 28.0 20.0 19.0 33.0212 28.0 11.0 51.0 10.0213 28.0 17.0 40.0 15.0214 28.0 17.0 35.0 20.0215 33.0 17.0 36.0 14.0216 33.0 12.0 25.0 30.0217 33.0 18.0 20.0 29.0218 34.0 10.0 45.0 11.0219 38.0 19.0 18.0 25.0220 38.0 24.0 24.0 14.0221 39.0 15.0 28.0 18.0222 39.0 11.0 40.0 10.0223 42.0 11.0 18.0 29.0224 42.0 12.0 28.0 18.0225 42.0 10.0 30.0 18.0226 42.5 13.0 34.5 10.0227 46.0 10.0 31.0 23.0228 46.0 11.0 33.0 10.0229 48.0 11.0 18.0 23.0230 48.0 12.0 21.0 19.0231 49.0 10.0 21.0 20.0232 49.0 15.0 26.0 10.0233 52.0 12.0 18.0 18.0234 52.0 12.0 20.0 16.0235 53.0 11.0 22.0 14.0236 53.0 11.0 24.0 12.0237 56.0 10.0 25.0 9.0238 56.0 10.0 21.0 13.0239 57.0 10.0 24.0 9.0240 59.6 10.0 19.4 11.0______________________________________
TABLE 8__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)201 900 Ag Air 30 120 300 150 5.4 40 2200 >10.sup.13202 900 Ag Air 30 120 300 150 5.3 41 2300 >10.sup.13203 910 Ag--Pd Air 30 120 300 150 5.2 43 2300 >10.sup.13204 880 Cu N.sub.2 30 120 250 120 5.5 40 2200 >10.sup.13205 850 Cu N.sub.2 30 120 250 120 5.5 43 2300 >10.sup.13206 850 Cu N.sub.2 30 120 250 120 5.1 46 2600 >10.sup.13207 900 Cu N.sub.2 + H.sub.2 40 150 300 150 5.8 40 2300 >10.sup.13208 910 Cu N.sub.2 + H.sub.2 40 150 300 150 5.6 44 2300 >10.sup.13209 900 Ag Air 40 150 300 150 5.3 48 2400 >10.sup.13210 900 Ag Air 40 150 300 150 5.0 49 2600 >10.sup.13211 890 Ag Air 40 150 300 200 5.8 43 2700 >10.sup.13212 880 Ag Air 40 150 300 200 5.6 47 2500 >10.sup.13213 900 Ag--Pd Air 40 150 300 200 5.5 49 2400 >10.sup.13214 880 Ag--Pd Air 30 150 300 200 5.2 52 2600 >10.sup.13215 880 Ag--Pd Air 30 100 200 100 6.5 41 2600 >10.sup.13216 900 Ag--Pd Air 30 100 200 100 6.2 45 2400 >10.sup.13217 870 Ag Air 30 100 250 120 6.2 46 2500 >10.sup.13218 850 Ag Air 30 100 250 120 6.0 49 2500 >10.sup.13219 890 Ag Air 30 100 250 120 6.2 47 2700 >10.sup.13220 900 Ag Air 35 100 300 150 6.1 47 2500 >10.sup.13__________________________________________________________________________
TABLE 9__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)221 900 Cu N.sub.2 35 100 300 150 6.1 43 2500 >10.sup.13222 850 Cu N.sub.2 35 100 300 150 5.8 48 2800 >10.sup.13223 930 Cu N.sub.2 35 100 300 150 6.8 39 2400 >10.sup.13224 900 Cu N.sub.2 40 150 300 150 6.1 45 2500 >10.sup.13225 910 Cu N.sub.2 + H.sub.2 40 150 350 150 5.9 48 2500 >10.sup.13226 900 Au Air 40 150 350 150 5.8 50 2600 >10.sup.13227 900 Ag Air 40 150 250 150 5.8 51 2700 >10.sup.13228 880 Cu N.sub.2 40 150 250 150 6.2 53 2800 >10.sup.13229 950 Cu N.sub.2 40 120 300 120 6.7 45 2500 >10.sup.13230 930 Ag--Pd Air 30 120 300 120 6.6 47 2500 >10.sup.13231 900 Ag--Pd Air 30 120 300 120 6.4 49 2400 >10.sup.13232 900 Au Air 30 120 300 120 6.2 51 2300 >10.sup.13233 930 Cu N.sub.2 30 120 250 100 6.7 48 2400 >10.sup.13234 910 Cu N.sub.2 30 120 250 100 6.5 50 2400 >10.sup.13235 950 Ag--Pd Air 30 120 250 100 6.4 51 2300 >10.sup.13236 950 Ag--Pd Air 30 100 200 80 6.4 51 2300 >10.sup.13237 930 Ag--Pd Air 40 100 250 120 6.7 50 2400 >10.sup.13238 960 Ag--Pd Air 40 100 250 120 6.5 52 2300 >10.sup.13239 900 Ag Air 40 100 250 120 6.4 54 2200 >10.sup.13240 900 Cu N.sub.2 40 80 200 80 6.5 55 2100 >10.sup.13__________________________________________________________________________
When the content of mullite powder is less than 10 wt %, the dielectric constant become higher than 7. On the other hand, if the content of mullite powder exceed 30 wt %, satisfactory sintering can not be carried out so that the insulation resistance becomes lower and the bending strength become lower than 2,000 kg/cm.sup.2.
When the particle size of alumina powder used becomes lower than 0.5 .mu.m or higher than 3 .mu.m, the particle size of borosilicate magnesium glass powder become lower than 1 .mu.m or higher than 5 .mu.m and the particle size of mullite powder become lower than 0.5 .mu.m or higher than 10 .mu.m, the mixed material powder can not be sintered satisfactorily, so that the resulting multilayer glass ceramic, substrate shows very poor reliability and hence can not be used in practical uses.
By the same reason as Example 2, practical multilayer glass ceramic substrate can not be obtained outside the proportions according to the present invention (12 to 59.6 wt % of alumina, 18 to 69.6 wt % of borosilicate magnesium glass and higher than 1 wt % of cordierite crystal).
By the same reason as Example 2 if the cordierite of magnesium in the borosilicate magnesium glass used becomes less than 5 wt % in terms of magnesium oxide, no or little cordierite crystal is produced by sintering operation.
EXAMPLE 4
(Alumina+borosilicate magnesium glass+.alpha.-quartz)
Example 2 is repeated except silica glass was replaced by .alpha.-quartz powder.
Namely, alumina powder, borosilicate (magnesium glass powder and .alpha.-quartz powder having the average particle size of 0.5 .mu.m to 10 .mu.m were intimately mixed at a proportion of (alumina+.alpha.-quartz): borosilicate magnesium glass of from 30 wt %:70 wt % to 60 wt %:40 wt %. The proportion of alumina powder was adjusted above 10 wt %.
Composition of glass ceramic layer of sintered substrates obtained are summarized in Table 10 and conductor, sintering conditions, numbers of layers and wiring specification used for manufacturing multilayer glass ceramic substrates as well as the results obtained are summarized in Tables 11 and 12. The sample numbers Table 10 correspond to those in Tables 11 and 12.
TABLE 10______________________________________quartza + borosilicate magnesium glass + .alpha.Composition ratio (wt %)Sample Borosilicate type CordieriteNumber Alumina .alpha.-quartz Glass crystal______________________________________301 12.0 21.0 37.0 30.0302 12.0 30.0 33.0 25.0303 12.4 11.0 69.6 20.0304 17.0 25.0 32.0 26.0305 17.0 10.0 23.0 50.0306 18.0 21.0 40.0 21.0307 22.0 18.0 25.0 35.0308 23.0 15.0 27.0 35.0309 23.0 19.0 38.0 20.0310 23.0 24.0 20.0 33.0311 28.0 20.0 19.0 33.0312 28.0 11.0 51.0 10.0313 28.0 17.0 40.0 15.0314 28.0 17.0 35.0 20.0315 33.0 17.0 36.0 14.0316 33.0 12.0 25.0 30.0317 33.0 18.0 20.0 29.0318 34.0 10.0 45.0 11.0319 38.0 19.0 18.0 25.0320 38.0 24.0 24.0 14.0321 39.0 15.0 28.0 18.0322 39.0 11.0 40.0 10.0323 42.0 11.0 18.0 29.0324 42.0 12.0 28.0 18.0325 42.0 10.0 30.0 18.0326 42.5 13.0 34.5 10.0327 46.0 10.0 31.0 23.0328 46.0 11.0 33.0 10.0329 48.0 11.0 18.0 23.0330 48.0 12.0 21.0 19.0331 49.0 10.0 21.0 20.0332 49.0 15.0 26.0 10.0333 52.0 12.0 18.0 18.0334 52.0 12.0 20.0 16.0335 53.0 11.0 22.0 14.0336 53.0 11.0 24.0 12.0337 56.0 10.0 25.0 9.0338 56.0 10.0 21.0 13.0339 57.0 10.0 24.0 9.0340 59.6 10.0 19.4 11.0______________________________________
TABLE 11__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)301 900 Ag Air 30 120 300 150 5.0 40 2200 >10.sup.13302 900 Ag Air 30 120 300 150 4.9 41 2300 >10.sup.13303 910 Ag--Pd Air 30 120 300 150 4.8 43 2300 >10.sup.13304 880 Cu N.sub.2 30 120 250 120 5.1 40 2200 >10.sup.13305 850 Cu N.sub.2 30 120 250 120 5.5 43 2300 >10.sup.13306 850 Cu N.sub.2 30 120 250 120 4.7 46 2600 >10.sup.13307 900 Cu N.sub.2 + H.sub.2 40 150 300 150 5.4 40 2300 >10.sup.13308 910 Cu N.sub.2 + H.sub.2 40 150 300 150 5.2 44 2300 >10.sup.13309 900 Ag Air 40 150 300 150 4.9 48 2400 >10.sup.13310 900 Ag Air 40 150 300 150 4.6 49 2600 >10.sup.13311 890 Ag Air 40 150 300 200 5.4 43 2700 >10.sup.13312 880 Ag Air 40 150 300 200 5.2 47 2500 >10.sup.13313 900 Ag--Pd Air 40 150 300 200 5.1 49 2400 >10.sup.13314 880 Ag--Pd Air 30 150 300 200 4.8 52 2600 >10.sup.13315 880 Ag--Pd Air 30 100 200 100 6.1 41 2600 >10.sup.13316 900 Ag--Pd Air 30 100 200 100 5.8 45 2400 >10.sup.13317 870 Ag Air 30 100 250 120 5.8 46 2500 >10.sup.13318 850 Ag Air 30 100 250 120 5.6 49 2500 >10.sup.13319 890 Ag Air 30 100 250 120 5.8 47 2700 >10.sup.13320 900 Ag Air 35 100 300 150 5.7 47 2500 >10.sup.13__________________________________________________________________________
TABLE 12__________________________________________________________________________ Number Size of Wire Coefficient Sintering of Wire Wire Via Specific of Thermal Breaking InsulationSample Temperature Sintering Layers Width Pitch Diameter Inductive Expansion Strength ResistanceNo (.degree.C.) Conductor Atmosphere (Layer) (.mu.m) (.mu.m) (.mu.m) Capacity (.times.10.sup.-7 deg.sup.-1 ) (kg/cm.sup.2) (.OMEGA. -__________________________________________________________________________ cm)321 900 Cu N.sub.2 35 100 300 150 5.7 43 2500 >10.sup.13322 850 Cu N.sub.2 35 100 300 150 5.4 48 2800 >10.sup.13323 930 Cu N.sub.2 35 100 300 150 6.4 39 2400 >10.sup.13324 900 Cu N.sub.2 40 150 300 150 5.7 45 2500 >10.sup.13325 910 Cu N.sub.2 + H.sub.2 40 150 350 150 5.5 48 2500 >10.sup.13326 900 Au Air 40 150 350 150 5.4 50 2600 >10.sup.13327 900 Ag Air 40 150 250 150 5.4 51 2700 >10.sup.13328 880 Cu N.sub.2 40 150 250 150 5.8 53 2800 >10.sup.13329 950 Cu N.sub.2 40 120 300 120 6.3 45 2500 >10.sup.13330 930 Ag--Pd Air 30 120 300 120 6.2 47 2500 >10.sup.13331 900 Ag--Pd Air 30 120 300 120 6.0 49 2400 >10.sup.13332 900 Au Air 30 120 300 120 5.8 51 2300 >10.sup.13333 930 Cu N.sub.2 30 120 250 100 6.3 48 2400 >10.sup.13334 910 Cu N.sub.2 30 120 250 100 6.1 50 2400 >10.sup.13335 950 Ag--Pd Air 30 120 250 100 6.0 51 2300 >10.sup.13336 950 Ag--Pd Air 30 100 200 80 6.0 51 2300 >10.sup.13337 930 Ag--Pd Air 40 100 250 120 6.3 50 2400 >10.sup.13338 960 Ag--Pd Air 40 100 250 120 6.1 52 2300 >10.sup.13339 900 Ag Air 40 100 250 120 6.0 54 2200 >10.sup.13340 900 Cu N.sub.2 40 80 200 80 6.1 55 2100 >10.sup.13__________________________________________________________________________
When the content of .alpha.-quartz powder is less than 10 wt %, the dielectric constant become higher than 7. On the other hand, if the content of a-quartz powder exceed 30 wt %, satisfactory sintering can not be carried out so that the insulation resistance becomes lower and the bending strength become lower than 2,000 kg/cm.sup.2.
When the particle size of alumina powder used becomes lower than 0.5 .mu.m or higher than 3 .mu.m, the particle size of borosilicate magnesium glass powder become lower than 1 .mu.m or higher than 5 .mu.m and the particle size of .alpha.-quartz powder become lower than 0.5 .mu.m or higher than 10 .mu.m, the mixed material powder can not be sintered satisfactorily, so that the resulting multilayer glass ceramic substrate shows very poor reliability and hence can not be used in practical uses.
By the same reason as Example 2, practical multilayer glass ceramic substrate can not be obtained outside the proportions according to the present invention (12 to 59.6 wt % of alumina, 18 to 69.6 wt % of borosilicate magnesium glass and higher than 1 wt % of cordierite crystal).
By the same reason as Example 2, if the, contents of magnesium in the borosilicate magnesium glass used becomes less than 5 wt % in term of magnesium oxide, no or little cordierite crystal is produced by sintering operation.

Number	Date	Country
4-147029	Jun 1992	JPX
4-147030	Jun 1992	JPX
4-147031	Jun 1992	JPX
4-159070	Jun 1992	JPX

Number	Name	Date
4536435	Utsumi	Aug 1985
4624896	Watanabe	Nov 1986
4764233	Ogihara	Aug 1988
4861646	Barringer	Aug 1989
5204289	Moh	Apr 1993
5283210	Kata	Feb 1994
5294477	Kanba	Mar 1994

	Number	Date	Country
Parent	513668	Aug 1995
Parent	73725	Jun 1993

Multilayer glass ceramic substrate and process for producing the same

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