JP5773625B2 - Glass ceramic wiring board - Google Patents

Description

  The present invention relates to a glass-ceramic wiring board having a low-resistance wiring layer mainly composed of silver, which is applied to a semiconductor element housing package or a high-frequency module board used in the mobile communication field.

  In recent years, with the increase in the speed and frequency of semiconductor elements, there is an increasing demand for wiring boards that can transmit high-frequency signals at high speed.

  As such a wiring board, a wiring layer having a low resistance and an insulating layer having a low relative dielectric constant are required.

  For this reason, a glass ceramic that has a lower relative dielectric constant than an insulating material mainly composed of alumina and has been used as an insulating base material and that can be co-fired with copper or silver as a wiring layer is used. A wiring board as an insulating layer has attracted attention.

  In addition, as represented by the popularization of mobile devices such as mobile phones, electronic devices are increasingly required to be miniaturized. For this reason, wiring boards mounted on electronic devices are also required to be smaller and thinner. Is getting bigger.

  The present applicant has so far proposed various wiring boards in order to satisfy the above requirements (for example, Patent Documents 1 to 5).

  FIG. 2 is a schematic cross-sectional view showing a conventional typical glass ceramic wiring board. The glass ceramic wiring board includes an insulating base 101 in which a plurality of glass ceramic insulating layers 111, 112, 113, and 114 are laminated, a through conductor 103 that passes through the glass ceramic insulating layers 111, 112, 113, and 114, and an insulating base 101. And an internal wiring layer 104 formed on the surface of the insulating substrate.

  In such a glass ceramic wiring substrate, the surface wiring layer 105 on the upper surface side of the surface wiring layer 105 formed on the surface of the insulating base 101 serves as a wiring layer for mounting a semiconductor element, an electronic component, etc. The surface wiring layer 105 on the lower surface side is a wiring layer for forming connection terminals 106 for connection to an external circuit board.

  Such a glass ceramic wiring board is manufactured by the following processes. First, after forming a glass ceramic green sheet containing a glass ceramic material as a main component, through holes are formed in the glass ceramic green sheet, and a conductive paste is filled. Next, the conductor paste is printed on the main surface of the glass ceramic green sheet in which the through-holes are filled with the conductor paste to form each conductor pattern that becomes the internal wiring layer 104 or the surface wiring layer 105. Next, a laminated body is formed by laminating a plurality of glass ceramic green sheets on which the conductor patterns to be the through conductor 103, the internal wiring layer 104, and the surface wiring layer 105 are formed, and then the laminated body is subjected to predetermined conditions. The substrate of the wiring board is formed by baking. Next, a glass-ceramic wiring board can be obtained by forming a plating film on the surface of the surface wiring layer 105 formed on the surface of the element body of the multilayer wiring board.

JP 2004-143010 A JP 2008-4646 A JP 2008-251782 A JP 2003-342060 A JP-A-2005-306714

  However, in the case of the glass ceramic wiring board disclosed in the above publication, in the evaluation as a glass ceramic sintered body having no wiring layer, the open porosity is low, the bending strength and the Young's modulus are high, and the mechanical reliability is improved. Although an excellent result can be obtained, when such a glass ceramic sintered body is used as the insulating substrate 101 and the surface wiring layer 105 is formed thereon, due to the influence of diffusion or solid solution of the material constituting the surface wiring layer 105. There is a problem that the strength of the insulating base 101 is lowered, and a crack is generated on the surface of the insulating base 101 in a deflection test in which the wiring substrate is deformed and evaluated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a glass-ceramic wiring board having no mechanical cracks in a deflection test and having excellent mechanical reliability.

The glass ceramic wiring board of the present invention has an insulating substrate in which a plurality of insulating layers made of glass ceramics are laminated, a surface wiring layer formed on the surface of the insulating substrate, and an internal arrangement provided inside.
A glass ceramic wiring board comprising a wire layer and a through conductor covered with the surface wiring layer and the internal wiring layer , wherein the insulating base contains alumina particles as a ceramic filler, and at least aluminum (Al), It has a glass phase containing silicon (Si) and calcium (Ca) as elements, the surface wiring layer and the internal wiring layer contain silver as a main component, and contain rhodium (Rh) , copper oxide and titanium oxide , the anorthite phase in a region other than the surface wiring layer of the surface of the insulating substrate to have a ceramic layer as a main crystal phase, bending strength of the glass ceramic wiring board Ri der than 190 MPa, the insulating substrate maximum diameter of the voids existing in the vicinity of the through conductors of the cross section, characterized in der Rukoto less than 5 [mu] m.

In the glass-ceramic wiring board, the insulating base further contains boron (B), magnesium (Mg), zirconium (Zr), barium (Ba), strontium (Sr), and yttrium (Y). While containing 39-41% by mass of alumina at a rate determined from Rietveld analysis, and when the amount obtained by removing the alumina from the insulating layer is 100% by mass, at a rate determined by quantitative analysis of fluorescent X-rays, 40-45 wt% of the Si in terms of SiO _2, 10 to 15 wt% of the Al in terms _{of Al} 2 _{O 3,} 0.5 to 2.0 wt% of the Ca in terms of CaO, the B _B 2 O ₃ 5-10 wt% in terms of the Mg 10 to 25 mass% in terms of MgO, the Zr 0.5 to 2.0 wt% in terms of ZrO _2, the Ba in terms of BaO 0-20 wt%, the Sr 0.2 to 0.8 wt% and the Y in terms of SrO _Y 2 _{O 3} is contained 0.5 to 1.5 wt% in terms of desirable.

  According to the glass ceramic wiring board of the present invention, it is possible to obtain a glass ceramic wiring board which is free from cracks in a deflection test and has excellent mechanical reliability.

It is a schematic sectional drawing of one Embodiment of the glass ceramic wiring board of this embodiment. It is a schematic sectional drawing of one Embodiment of the conventional glass ceramic wiring board.

Hereinafter, an embodiment of the glass-ceramic wiring board of the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of one embodiment of the glass ceramic wiring board of the present embodiment.

  The glass ceramic wiring board shown in FIG. 1 includes an insulating substrate 1 in which insulating layers 11, 12, 13, and 14 made of a plurality of glass ceramics are laminated, a surface wiring layer 2 provided on the surface of the insulating substrate 1, and an insulating substrate. An internal wiring layer 3 provided inside the base 1 and a through conductor 5 are provided.

The insulating substrate 1 constituting the glass ceramic wiring board of the present embodiment contains alumina particles as a ceramic filler and has a glass phase containing at least aluminum (Al), silicon (Si) and calcium (Ca) as elements. And a ceramic layer 7 having an anorthite (CaAl ₂ Si ₂ O ₈ ) phase as a main crystal phase in a region other than the surface wiring layer in the surface of the insulating substrate 1, and the insulating layers 11, 12, 13, 14 has a bending strength of 190 MPa or more. The surface wiring layer 2 is composed of a conductor material containing Ag as a main component and containing rhodium (Rh) and copper oxide.

  As a result, when a deflection test for deforming the glass ceramic wiring board is performed, a glass ceramic wiring board having no mechanical cracks and no cracks can be obtained.

  Here, the anorthite phase on the surface of the insulating substrate 1 can prevent the occurrence of cracks in the deflection test, and the bending strength of the insulating substrate 1 can be 230 MPa or more. It is desirable that

  In the glass-ceramic wiring board of the present embodiment, the region having the anorthite phase in the region other than the surface wiring layer on the surface of the insulating substrate 1 is mainly the anorthite phase based on the analysis of micro-region X-ray diffraction. In this case, when the cross section of the insulating substrate 1 constituting the glass ceramic wiring board is subjected to elemental analysis using energy dispersive X-ray spectroscopy (EDS), the insulating layer 1 is present. It refers to a portion where elements (Ca, Al and Si) constituting the anorthite phase are concentrated from the surface of the substrate 1 to the inside.

  The determination that rhodium (Rh) and copper oxide components are present in the surface wiring layer 2 is performed when spot-dispersion energy dispersive X-ray spectroscopy (EDS) is performed on a part of the surface wiring layer 2. Let the rhodium and copper X-ray peaks be greater than the noise level.

  Further, in the deflection test for the glass ceramic wiring board of the present embodiment, the insulating substrate 1 constituting the glass ceramic wiring board is formed when the glass ceramic wiring board of a predetermined size is deformed by pressing the substantially central portion at a constant speed. The presence or absence of cracks generated on the surface of the film is evaluated. The conditions of the deflection test are, for example, a glass ceramic wiring board sample having a size of 45 mm × 45 mm × 2 mm, pressurization speed: 1.0 mm / second, deflection amount: 0.5 mm, holding time: 5 ± 1 second. Then, the surface on the convexly deformed side during the deflection test is observed with a microscope, and a crack with a length of 0.5 mm or more is observed as having a crack.

In the glass ceramic wiring board of this embodiment, the insulating base further contains boron (B), magnesium (Mg), zirconium (Zr), barium (Ba), strontium (Sr), and yttrium (Y), and X-rays Quantitative analysis of fluorescent X-rays when containing 39 to 41% by mass of alumina particles at a ratio determined by Rietveld diffraction analysis and 100% by mass of the amount of alumina removed from an insulating layer made of glass ceramic. at a rate determined, 40-45 wt% of Si in terms of SiO _2, 10 to 15 wt% of Al in terms _{of Al} 2 _{O 3,} 0.5 to 2.0 wt% of Ca in terms of CaO, a B _{B 2} 5 to 10% by mass in terms of O ₃ , 10 to 25% by mass in terms of MgO, Zr to 0.5 to 2.0% by mass in terms of ZrO ₂ ,
It is desirable to contain 10 to 20% by mass of Ba in terms of BaO, 0.2 to 0.8% by mass of Sr in terms of SrO, and 0.5 to 1.5% by mass in terms of Y ₂ O ₃ .

  When the insulating substrate 1 has the above composition, the insulating substrate 1 can be further densified, and the insulating substrate 1, the surface wiring layer 2 formed on the surface of the insulating substrate 1, and the internal wiring layer 4, and the internal wiring layer 4 are formed. And the joining property with the penetration conductor 5 can be improved. At this time, if the surface wiring layer 2 and the internal wiring layer 4 contain Ti, voids in the vicinity of the through conductor 5 covered by the surface wiring layer 2 and the internal wiring layer 4 can be reduced.

  In this case, the degree of densification of the insulating substrate 1 can be determined by measuring the maximum void diameter obtained from observation of the surface of the insulating substrate 1, and the maximum void diameter is desirably 10 μm or less in the glass ceramic wiring board of the present embodiment. .

  Further, regarding the bonding property between the surface wiring layer 2, the internal wiring layer 4, the through conductor 5 and the insulating base 1 formed on the surface or inside of the insulating base 1, a cross section of the insulating base 1 is used with a scanning electron microscope. And evaluating from the presence or absence of voids of a certain size or more between the through conductor and the insulating substrate 1 in the cross section. In this case, the number of through conductors 5 in which no void having a maximum diameter of 5 μm or more exists between the through conductor 5 and the insulating base 1 in the cross section of the insulating base 1 is obtained by evaluation. A through conductor 5 having a void having a maximum diameter of 5 μm or more between the through conductor 5 in the cross section of the insulating base 1 and the insulating base 1 is counted as defective.

Moreover, when the composition of the insulating substrate 1 is the above composition, the bending strength can be made 290 MPa or more, the relative dielectric constant can be made 9 or less, and the dielectric loss can be made 20 × 10 ⁻⁴ or less. The dielectric properties of the insulating substrate 1 can also be improved.

  Thus, it is possible to obtain a glass ceramic wiring board having excellent dielectric characteristics, being dense, and having high mechanical reliability.

  Next, the manufacturing method of a glass ceramic wiring board is demonstrated. First, glass powder and a ceramic filler for preparing a glass ceramic green sheet are prepared.

As the glass powder, a powder containing at least Al ₂ O ₃ , SiO ₂ and CaO is used. This glass powder becomes glass in which anorthite is deposited on the surface of the insulating substrate 1 by firing.

Also, 10 in the case of manufacturing the glass ceramic wiring board of the present embodiment, as the glass powder for forming the insulating base 1, 40-45 wt% of Si in terms of SiO _2, the Al in terms _{of Al} 2 _{O 3} 15 wt%, the Ca 0.5 to 2.0 wt% in terms of CaO, 5-10 wt% of B in terms _{of B} 2 _{O 3,} 10 to 25 wt% of Mg in terms of MgO, the Zr in terms of ZrO ₂ 0.5-2.0 wt%, 10 to 20 wt% of Ba in terms of BaO, of Sr in terms of SrO and 0.2 to 0.8 wt% and Y in terms _{of Y} 2 _{O 3} 0.5 to 1. When the material containing 5% by mass is used, it is possible to obtain a glass ceramic wiring board which is further excellent in dielectric properties, is dense and has high mechanical reliability.

  Moreover, when manufacturing the glass ceramic wiring board of this embodiment, an alumina powder is used as a ceramic filler for forming the insulating substrate 1 because the mechanical strength of the insulating substrate 1 is increased. In this case, the average particle size of the alumina powder is preferably 2 to 5 μm.

Next, a suitable organic binder and organic solvent are mixed with a mixture of glass powder and ceramic filler (total 100 mass%) to obtain a slurry. From the obtained slurry, a glass ceramic green sheet is produced by a desired forming means such as a doctor blade method, a calender roll method, a rolling method or the like. In this case, the ratio of the glass powder and the ceramic filler in the mixture is preferably 57 to 61% by mass for the glass powder and 39 to 43% by mass for the ceramic filler. It becomes possible to obtain.

  Next, a through hole is formed in the obtained glass ceramic green sheet by punching or laser processing. The through hole is filled with a conductor paste for a through conductor containing silver powder as a main component.

Also, on the desired glass ceramic green sheet, a conductor pattern for the surface wiring layer or the internal wiring layer is formed by screen printing or gravure printing using a wiring layer conductive paste containing silver powder as a main component. To do. The conductive paste is 97 to 99% by mass of silver (Ag), 0.01 to 0.05% by mass of rhodium (Rh) in the form of metal powder, 0.8 to 2% by mass of copper oxide (CuO), TiO. _It is good to use what contains 1-2 mass% of 2. Here, the use of TiO ₂ added as the conductive paste is said to improve the bondability between the insulating substrate 1 and the insulating substrate 1, such as the surface wiring layer 2, the internal wiring layer 3, and the through conductor 5 For reasons.

  Next, a through-hole formed in the glass ceramic green sheet is filled with a conductor paste for a through conductor, and a conductor pattern for an internal wiring layer or a surface wiring layer is formed on the main surface of the glass ceramic green sheet. Next, a laminated body is produced by laminating a plurality of glass ceramic green sheets on which a conductor pattern is formed, and laminating the glass ceramic green sheets using a thermocompression bonding method or a laminating aid.

  Next, the obtained laminate is fired. Firing is performed after degreasing in an atmospheric atmosphere and then in an air atmosphere at a temperature of 850 ° C. to 950 ° C. for 1 to 2 hours.

In the glass ceramic wiring board of the present embodiment, the ceramic layer having the anorthite phase on the surface of the insulating base 1 can be formed on the glass ceramic green sheet to be the insulating base 1 on the anorthite (CaAl ₂ Si ₂ O ₈ ). A glass paste containing Al ₂ O ₃ , SiO ₂ and CaO having the following elemental components is used, and a conductor paste containing silver as a main component and containing a small amount of rhodium (Rh) and copper oxide is used as the conductor paste. The rhodium (Rh) and copper oxide contained in the conductive paste mainly composed of silver act catalytically on Al ₂ O ₃ , SiO ₂ and CaO contained in the glass ceramic green sheet. This is to facilitate the formation of the anorthite phase. Therefore, the ceramic layer 7 having an anorthite phase is selectively formed near the surface of the glass ceramic green sheet on which the conductor paste is printed.

  On the other hand, when a conductor paste not containing rhodium (Rh) and copper oxide is used in a conductor paste containing silver as a main component, an anorthite phase is not formed on the surface of the insulating substrate 1, and therefore, glass When a deflection test of the ceramic wiring substrate is performed, cracks are observed on the surface of the insulating substrate 1 constituting the glass ceramic wiring substrate.

  By the manufacturing method described above, a glass ceramic wiring board having an anorthite phase on the surface of the insulating base and having a bending strength of 190 MPa or more and having no cracks in the deflection test can be obtained.

As the glass powder, glass powder having the composition shown in Table 1 and alumina powder as the ceramic filler were prepared and weighed and mixed so as to have the ratio shown in Table 1. The average particle size of the glass powder was 3.5 μm, and the average particle size of the alumina powder was 3.5 μm.

  To this mixture, an organic binder containing isobutyl methacrylate as the main chain and toluene as a solvent was added, and dibutyl phthalate was added as an organic solvent, and mixed well to prepare a slurry. A green sheet was produced.

  After the through hole was formed in the obtained glass ceramic green sheet by punching, the through hole was filled with a conductive paste for the through hole. The conductor paste for the through holes was prepared by adjusting the viscosity by adding an acrylic binder and terpineol to Ag powder.

Next, a conductor pattern for an internal wiring layer or a conductor pattern for a surface wiring layer was formed on the surface of a glass ceramic green sheet filled with a conductor paste for through holes. As the conductor paste for forming the conductor pattern for the internal wiring layer or the conductor pattern for the surface wiring layer, a conductor paste having the composition shown in Table 2 was used. In this conductor paste, Rh powder, CuO powder and TiO ₂ powder were mixed with the inorganic components shown in Table 2 so as to have the ratio shown in Table 2, and an acrylic binder and terpineol were added thereto to adjust the viscosity. . In addition, the average particle diameter of the silver powder contained in the conductor paste for the surface wiring layer is 5 μm, and the average particle diameter of the silver powder contained in the conductor paste for the internal wiring layer is 2 μm. CuO powder and TiO ₂ powder having an average particle diameter of 1 to 2 μm were used.

  A plurality of glass ceramic green sheets with conductor patterns formed in this manner were aligned and 20 layers were laminated by thermocompression bonding to produce a laminate.

  Next, degreasing was performed in an air atmosphere under the conditions of a temperature of 725 ° C. and a holding time of 3 hours, and then in an air atmosphere under the conditions of a maximum temperature of 900 ° C. and a holding time of 1 hour. Firing was carried out to produce an element body of a glass ceramic wiring board having a size of 45 mm in length, 45 mm in width, and 2 mm in thickness.

  The following measurements were performed on the multilayer wiring board obtained by the above method.

  First, for the deflection test, with respect to the produced glass-ceramic wiring board (size: 45 mm × 45 mm × 2 mm), pressing speed: 1.0 mm / second, deflection amount: 0.5 mm, holding time: 5 ± 1 second Then, the surface of the convexly deformed side during the deflection test was observed with a microscope, and a crack having a length of 0.5 mm or more was observed as having a crack. The number of samples was 10.

  The bending strength was obtained by cutting out the central portion of the produced glass ceramic wiring board into a size of 45 mm × 5 mm × 2 mm and conducting a three-point bending strength test. The number of samples at this time was 20.

  The analysis of the anorthite phase formed on the surface of the insulating substrate constituting the glass ceramic wiring board was conducted using micro-region X-ray diffraction. In addition, the thickness of the ceramic layer having the anorthic phase in the insulating base is determined by elemental analysis of the cross section of the insulating base using energy dispersive X-ray spectroscopy (EDS), and the anorthic phase is formed from the surface of the insulating base to the inside. The thickness of the portion where the elements (Ca, Al and Si) to be concentrated are concentrated. The number of samples was one.

Regarding the bonding property between the insulating substrate 1 and the conductors such as the surface wiring layer 2, the internal wiring layer 4 and the through conductor 5, the cross section of the insulating substrate 1 is observed using a scanning electron microscope, and the through conductor of the cross section is insulated. A case where no void of 5 μm or more was seen between the substrate 1 and the substrate 1 was judged good, and a case where even one void of 5 μm or more was seen was judged as bad. The number of samples was one.

  Regarding the maximum void diameter, the obtained body of the glass ceramic wiring substrate was subjected to cross-sectional polishing, and a 1000 μm × 1000 μm range of the central portion in the polished cross-section was evaluated using a scanning electron microscope. The number of samples was one.

  In addition, regarding the relative dielectric constant and dielectric loss of the insulating substrate, the insulation obtained by laminating a plurality of glass ceramic green sheets used for producing the glass ceramic wiring board and firing under the same conditions as the glass ceramic wiring board The substrate was processed to 50 mm × 50 mm × 1 mm and measured by the cavity resonator method. The measurement frequency at this time was 2 GHz. The number of samples was three. The results are shown in Table 3.

Regarding the composition of the glass ceramics, first, the X-ray diffraction Rietveld analysis was performed on the sample obtained by pulverizing the glass ceramic wiring board to determine the proportion of alumina contained in the glass ceramic, and then the pulverized sample was obtained. Using X-ray fluorescence analysis,
The composition of glass ceramics was determined, and the composition of components other than alumina in the glass ceramics was determined from the composition determined from fluorescent X-rays and the composition determined from Rietveld analysis of X-ray diffraction. As a result, the obtained glass ceramics had alumina particles after sintering, and the composition thereof was consistent with the preparation composition shown in Table 1.

As is apparent from the results shown in Table 3, the specimen (sample Nanba1,5～45), samples the occurrence of cracks in the bending test did not.

In particular, the composition of the insulating substrate contains 39 to 41% by mass of alumina particles in a proportion determined from the X-ray diffraction Rietveld analysis, and the proportion of the glass phase excluding the alumina particles from the insulating layer made of glass ceramics is 100%. %, Si is 40 to 45% by mass in terms of SiO ₂ , Al is 10 to 15% by mass in terms of Al ₂ O ₃ , and Ca is 0 in terms of CaO. .5～2.0 mass%, 5-10 mass% of B in terms _{of B} 2 _{O 3,} 10 to 25 wt% of Mg in terms of MgO, 0.5 to 2.0 wt% of Zr in terms of ZrO _2, Sample No. containing Ba in an amount of 10 to 20% by mass in terms of BaO, Sr in an amount of 0.2 to 0.8% by mass in terms of SrO, and Y in an amount of 0.5 to 1.5% by mass in terms of Y ₂ O ₃ . 1, 6-8, 10, 11, 14, 15, 18, 19, 22, 23, 26, 27, 30, 31, 34, 35, 38, 39, 42 and 43 have no voids near the through conductor The bending strength was 290 MPa or more, the relative dielectric constant was 9 or less, and the dielectric loss was 20 × 10 ⁻⁴ or less.

  In contrast, Sample No. which does not have a ceramic layer whose main crystal phase is the anorthite phase in a region other than the surface wiring layer on the surface of the insulating substrate. In 2-4, the crack was seen in the bending test.

DESCRIPTION OF SYMBOLS 1 ... Insulating base | substrate 11, 12, 13, 14 ... Insulating layer 2 which consists of glass ceramics ... Surface wiring layer 3 ... Internal wiring layer 5 ... Through conductor 7 ... Anorthite phase Ceramic layer as main crystal phase

Claims (2)

An insulating substrate in which a plurality of insulating layers made of glass ceramics are laminated, a surface wiring layer formed on the surface of the insulating substrate, an internal wiring layer provided therein, and the surface wiring layer and the internal wiring layer are covered. A glass ceramic wiring board having a through conductor , wherein the insulating base contains alumina particles as a ceramic filler, and includes a glass phase containing at least aluminum (Al), silicon (Si) and calcium (Ca) as elements. And the surface wiring layer and the internal wiring layer contain silver as a main component and contain rhodium (Rh) , copper oxide and titanium oxide, and the surface of the insulating substrate has an anode in a region other than the surface wiring layer. A ceramic layer having a site phase as a main crystal phase, and the bending strength of the glass ceramic wiring board is 190 MPa or more. Ri above der, the insulating substrate is a glass ceramic wiring board maximum diameter of voids existing in the vicinity of the through conductors of the cross section, characterized in der Rukoto less than 5 [mu] m. The insulating substrate further contains boron (B), magnesium (Mg), zirconium (Zr), barium (Ba), strontium (Sr), and yttrium (Y), and a ratio determined by Rietveld analysis of X-ray diffraction. In addition, 39 to 41% by mass of alumina and 100% by mass when the amount of the alumina removed from the insulating layer is 100% by mass, the Si is converted into SiO ₂ at a ratio determined by quantitative analysis of fluorescent X-rays. 40-45 wt%, 10-15 wt% in the Al _Al 2 _{O 3} in terms of, 0.5 to 2.0 wt% of the Ca in terms of CaO, 5-10 wt said B in terms _{of B} 2 _{O 3} %, 10 to 25 wt% of the Mg in terms of MgO, 0.5 to 2.0 mass% of the Zr in terms of ZrO _2, 10 to 20 wt% in terms of BaO the Ba, the Sr SrO Glass ceramic wiring board according to claim 1, 0.2 to 0.8% by weight calculated and the Y, characterized in that it contains 0.5 to 1.5 wt% in terms _{of Y} 2 _{O 3.}

Images