JPH11130533A - Circuit board and its mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board burnable at 800-1000 deg.C, having low dielectric constant and low dielectric loss in high frequency region and high thermal expansion coefficient and enabling highly reliable mounting on a printed circuit board and provide its mounting structure. SOLUTION: A circuit board having an insulation substrate 1, a circuit layer 5 and connection terminals 8 is placed on an outer electric circuit board B having circuit conductors 10 on a surface of an insulation substrate 9 containing an organic resin and the connecting terminals 8 are soldered to the circuit conductors 10 to complete the mounting operation. The insulation substrate 1 of the circuit board A is composed of a sintered double oxide containing Si, Al, Mg, Zn, Sr and Ti as constituent elements, composed mainly of an SiO2 crystal phase (Si) such as quartz and a spinel-type crystal phase (SP) such as garnite, further containing a double oxide crystal phase (SL) containing Sr, Al and Si such as slawsonite and having a thermal expansion coefficient of >=7 ppm/ deg.C in the temperature range from the room temperature to 400 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board applied to a package for accommodating a semiconductor element, a multilayer wiring board, and the like, and more particularly to a wiring board which can be co-fired with copper or silver. The present invention relates to a wiring board that can be mounted with high reliability on an external electric circuit board made of an organic resin such as an organic resin, and a mounting structure thereof.

[0002]

2. Description of the Related Art Conventionally, as a ceramic multilayer wiring board, a ceramic multilayer wiring board in which a wiring layer made of a refractory metal such as tungsten or molybdenum is formed on the surface or inside of an insulating substrate made of an alumina-based sintered body has been most widely used. I have.

Further, recently, with the era of advanced information, the frequency band to be used is shifting to higher and higher frequencies. In such a high-frequency wiring board that requires transmission of a high-frequency signal, in order to transmit a high-frequency signal without loss, the resistance of the conductor forming the wiring layer is small, and the dielectric in the high-frequency region of the insulating substrate is low. Low loss is required.

However, conventional tungsten (W),
A high melting point metal such as molybdenum (Mo) has a large conductor resistance and a low signal propagation speed, and it is difficult to propagate a signal in a high frequency region of 30 GHz or more. Therefore, instead of metals such as W and Mo, copper, It is necessary to use low resistance metals such as silver and gold.

A wiring layer made of such a low-resistance metal is
Since it is impossible to co-fire with alumina, recently, a wiring board using glass or a composite material of glass and ceramic, that is, a so-called glass ceramic as an insulating substrate has been developed. For example, as disclosed in Japanese Patent Publication No. 4-12639, a multilayer wiring board obtained by adding an SiO ₂ filler to glass and simultaneously firing a wiring layer made of a low-resistance metal such as copper, silver, and gold at a temperature of 900 to 1000 ° C. Further, as disclosed in Japanese Patent Application Laid-Open No. Sho 60-240135, a material in which a filler such as Al ₂ O ₃ , zirconia, or mullite is added to a zinc borosilicate glass and co-fired with a low-resistance metal has been proposed. . In addition,
Japanese Patent Application No. 298919 proposes a glass ceramic material in which mullite or cordierite is precipitated as a crystal phase.

In addition, when a wiring board such as a multilayer wiring board or a package for housing semiconductor elements is mounted on a printed board containing an organic resin by an insulating substrate such as a mother board, the mounting is performed by a stress generated due to a difference in thermal expansion from the printed board. It is desirable that the thermal expansion coefficient of the insulating substrate be similar to that of the printed circuit board in order to prevent the portions from peeling or cracking.

[0007]

However, in the above-described conventional glass ceramics, the conventional glass ceramics sintered body is made of alumina even if it can be co-fired with a low-resistance metal such as copper, silver or gold. The thermal expansion coefficient was lower than that of the sintered compact, which was about 3 to 6 ppm / ° C., and when mounted on a printed circuit board, the reliability of the mounting was low and was not practically satisfactory. Further, it has not been specifically studied as an insulating substrate of a wiring board using a high frequency signal such as a microwave or a millimeter wave, and most of them have high dielectric loss and do not have sufficiently high frequency characteristics.

Accordingly, the present invention is capable of firing at 800 to 1000 ° C. so as to enable multilayering using gold, silver and copper as wiring conductors, and has a high thermal expansion coefficient close to the thermal expansion coefficient of a printed circuit board. It is another object of the present invention to provide a wiring board having a low dielectric constant and a low dielectric loss tangent even in a high frequency region. Another object of the present invention is to provide a wiring board mounting structure that can be mounted on an external electric circuit board such as a printed board with high reliability.

[0009]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventor has found that a wiring board having a wiring layer disposed on the surface or inside of the insulating board is characterized by:
A composite oxide sintered body containing Si, Al, Mg, Sr, Ti and Zn as constituent elements, in which a SiO ₂ crystal phase and a spinel oxide crystal containing at least Zn and Al are contained. Phase and at least Sr, Al
The present inventors have found that, by precipitating a composite oxide crystal phase containing Si and Si as a constituent phase, a high thermal expansion can be achieved, a low dielectric constant, and a low dielectric loss in a high frequency region can be realized. Was.

That is, the wiring board of the present invention comprises: an insulating substrate;
A wiring layer is provided on the surface or inside thereof, and the insulating substrate contains Si, Al, Mg, Zn, Sr and Ti as constituent elements, and at least a SiO ₂ crystal phase as a crystal phase. A sintered body containing a spinel-type oxide crystal phase containing Zn and Al and a composite oxide crystal phase containing at least Sr, Al and Si, and having a thermal expansion coefficient of 7 ppm / ° C. or more from room temperature to 400 ° C. It is characterized by comprising. Further, the Si
The O ₂ crystal phase is a quartz crystal phase, the composite oxide crystal phase containing at least Sr, Al and Si is a monoclinic crystal, particularly a slausonite crystal phase. The binder is SiO ₂ , Al ₂
O _3, MgO, glass powder 30-95 wt% containing ZnO and B ₂ O _3, SiO ₂ 4.9~40 wt%, S
0.1 to 10% by weight of a composite oxide of rO and TiO ₂ , Z
nO0~30 wt%, after molding the B ₂ O ₃ mixture consisting of 0-10% by weight, obtained by sintering at a temperature of 800 to 1000 ° C., the glass powder when the, SiO ₂ 40 to
52% by weight, 14 to 32% by weight of Al ₂ O ₃ , MgO 4 to
24 wt%, ZnO1~16 wt%, B ₂ O ₃ 5~15
It is characterized by being composed of a percentage by weight.

Further, according to the mounting structure of the wiring board of the present invention, there is provided an insulating substrate, a wiring layer disposed on or inside the insulating substrate, and connection terminals for connecting to an external electric circuit. The wiring board is placed on an external electric circuit board having a wiring conductor formed on at least the surface of an insulator containing an organic resin, and the connection terminals of the wiring board are brazed to the wiring conductor of the external electric circuit board. The insulating substrate of the wiring substrate is made of Si, Al, Mg, Zn, S
In addition to containing r and Ti as constituent elements, the crystal phase includes a SiO ₂ crystal phase, a spinel oxide crystal phase containing at least Zn and Al, and a composite oxide crystal phase containing at least Sr, Al and Si. And a sintered body having a coefficient of thermal expansion from room temperature to 400 ° C. of 7 ppm / ° C. or more.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wiring board according to the present invention will be described with reference to FIG. FIG. 1 is a schematic sectional view of a semiconductor storage package, particularly a ball grid array (BGA) type package in which connection terminals are formed of ball-shaped terminals. According to FIG. 1, the package A has a cavity 3 formed by an insulating substrate 1 made of an insulating material and a lid 2, and a semiconductor element 4 is mounted in the cavity 3.

Further, on the surface and inside of the insulating substrate 1,
A wiring layer 5 electrically connected to the semiconductor element 4 is formed. The wiring layer 5 is desirably made of a low-resistance metal such as copper, silver, or gold in order to minimize conductor loss when transmitting a high-frequency signal. Further, the wiring layer 5 has a frequency of 1 GHz or more, particularly 20 GHz or more,
When transmitting a high-frequency signal of not less than 70 Hz or even 70 GHz, it is necessary to transmit the high-frequency signal without loss. Therefore, known strip lines, microstrip lines, coplanar lines, and dielectric waveguides are known. It is composed of at least one of the lines.

In the package shown in FIG. 1, a connection electrode layer 6 is formed on the bottom surface of the insulating substrate 1 and is connected to the wiring layer 5 in the package. A ball-shaped terminal 8 is formed on the connection electrode layer 6 with a brazing material 7 such as solder.

According to the present invention, the insulating substrate 1 in the package as shown in FIG.
It is composed of a composite oxide sintered body containing g, Zn, Sr and Ti as constituent elements. Further, as shown in a schematic diagram for explaining the structure of the sintered body in FIG.
A crystal phase (Si) composed of O ₂ , at least ZnO and A
One of the spinel crystal phases (SP) consisting of l ₂ O ₃ is the main crystal phase, and these two crystals occupy 50% or more of the total crystal phase in the sintered body. Further, according to the present invention, a complex oxide crystal phase (SL) containing at least Sr, Al and Si is contained as a crystal phase other than the above two crystal phases.

The crystal phase (Si) composed of SiO ₂ is desirably composed of a quartz-type crystal phase.
Spinel type crystal phase mainly composed of nO and Al ₂ O ₃ (S
Examples of P) include garnite represented by ZnAl ₂ O ₄ . The composite oxide crystal phase (SL) containing at least Sr, Al and Si is composed of a monoclinic crystal, and is particularly preferably a slausonite type crystal phase represented by SrAl ₂ Si ₂ O ₈ .

In each of the above crystal phases, other metal elements than the main constituent metal elements may be dissolved in a solid solution as long as the crystal structure is not changed. For example, ZnAl ₂ O ₄
Has a solid solution of MgAl ₂ O ₄ and (Zn, Mg) Al
_It may be composed of a spinel type crystal phase of ₂ O ₄ . Also,
In the quartz-type crystal phase, Zn and B other than SiO ₂ may form a solid solution.

According to the present invention, a cordierite type crystal phase represented by 2MgO.2Al ₂ O ₃ .5SiO ₂ may be present in a small amount in addition to the above three crystals. Furthermore, in the structure of the sintered body,
SiO ₂ , or SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , S
A glass phase containing rO may be present.

In the present invention, the overall composition of the composite oxide sintered body constituting the insulating substrate includes Si, Al, M
g, Zn, when the total amount of an oxide in terms of respective metal elements of Sr and Ti is 100 wt%, a SiO ₂ from 30 to 6
0 wt%, the Al ₂ O ₃ 18 to 25 wt%, the MgO 5
To 13 wt%, the ZnO 5 to 35% by weight, the B ₂ O ₃ 5
12wt%, SrO1～3 wt%, it is preferably made of the ratio of TiO ₂ 1 to 3 wt%.

According to the present invention, as the crystal phase, the SiO ₂ crystal phase, the spinel type crystal phase and Sr, Al
The complex oxide crystal phase containing Si and Si (e.g., slausonite type crystal) has a high thermal expansion characteristic per se at room temperature to 400 [deg.] C.
Since the garnite type crystal and the slausonite type crystal have a thermal expansion coefficient of 7 to 8 ppm / ° C at 3 to 20 ppm / ° C, the thermal expansion coefficient of the insulating substrate is increased by forming a sintered body from these crystal phases. Tend to be. In order to increase the coefficient of thermal expansion, it is desirable to use SiO ₂
It is preferred that the crystal phase, particularly the quartz crystal phase, be the largest. Note that cristobalite and tridymite other than quartz are available as the SiO ₂ crystal phase.
It is not desirable because it has a bending point of the thermal expansion coefficient near 00 ° C.

According to the present invention, the insulating substrate made of the above-described composite oxide sintered body has a low dielectric constant of 6 or less, particularly 5 or less, and improves the reliability of mounting on a printed circuit board. The thermal expansion coefficient of the insulating substrate from room temperature to 400 ° C. is 7 ppm / ° C. or more, particularly 9 ppm / ° C. or more,
It is preferably 0 ppm / ° C. or more. This is because if the coefficient of thermal expansion is lower than 7 ppm / ° C., the thermal expansion difference between the printed circuit board and the printed circuit board and the package due to thermal cycling due to repetitive temperature cycling due to the stoppage of the operation of the semiconductor element may cause the thermal expansion. Stress due to the difference in expansion occurs,
This is because cracks and the like occur in the mounting portion, which impairs the reliability of the mounting structure.

Therefore, the mounting structure according to the present invention is shown in FIG.
As shown in FIG. 3, an external electric circuit board B having a wiring conductor 10 formed on the surface of an insulating substrate 9 made of an insulating material containing an organic resin such as a polyimide resin, an epoxy resin, and a phenol resin is interposed with a brazing material. Is to be implemented.
Specifically, the ball-shaped terminal 8 attached to the bottom surface of the insulating substrate 1 in the package A and the wiring conductor 10 of the external electric circuit board B are brought into contact with each other to form a brazing material 11 such as solder such as Pb-Sn. Is mounted by brazing. Also,
The ball-shaped terminal 8 itself may be melted and connected to the wiring conductor 10.

According to the present invention, in such a surface mount type package as is mounted by brazing with such ball-shaped terminals 8 interposed therebetween, it is mounted on an external electric circuit board made of an insulating substrate containing an organic resin. In this case, the thermal expansion difference between the external electric circuit board and the insulating substrate can be made smaller than that of the conventional ceramic material. Therefore, even when a thermal cycle is applied to such a mounting structure, the occurrence of stress is suppressed. As a result, the long-term reliability of the mounting structure can be improved.

Next, a method of manufacturing a composite oxide sintered body constituting an insulating substrate of a wiring board according to the present invention will be described. First, as starting materials, SiO ₂ , Al
Crystallized glass powder containing ₂ O ₃ , MgO, ZnO, B ₂ O ₃ , and ZnO powder, SiO ₂ powder, or willemite (Zn ₂ SiO ₄ ) powder as filler component, B
SrO and TiO ₂ such as ₂ O ₃ powder and SrTiO ₃
And a mixture thereof in a desired ratio.

The desirable composition of the crystallized glass to be used is as follows: SiO ₂ 40 to 52% by weight, Al ₂ O ₃ 14 to 32
%, MgO 4 to 24% by weight, ZnO 1 to 16% by weight, and B ₂ O ₃ 5 to 15% by weight.

Then, 4.9 to 40% of SiO ₂ is added to 30 to 95% by weight, particularly 60 to 90% by weight of the glass powder.
Wt%, in particular 9 to 30 wt%, SrO and 0.1 to 10 wt% of TiO ₂ in total, added in particular in a proportion of 1 to 5 wt%, further 0 to 30 wt% of ZnO as an optional component, B
₂ O ₃ is added and mixed at a ratio of 0 to 10% by weight.

The reason for limiting each component in the above-mentioned raw material powder to the above range is that if the glass powder is less than 30% by weight, firing at a temperature of 1000 ° C. or less is impossible, and If there is too much, the glass melts at the firing temperature, and it becomes impossible to produce a sintered body.

If the amount of SiO ₂ is less than 4.9% by weight, the sintered body having a high thermal expansion cannot be obtained because the absolute amount of the SiO ₂ crystal phase in the sintered body is reduced. %, It becomes difficult to sinter and cannot be densified at a firing temperature of 1000 ° C. or less.

SrO and TiO ₂ are most preferably added as a composite oxide such as SrTiO _{3. In} particular, by adding SrO and TiO ₂ , the sinterability of such a system can be greatly improved. Along with firing,
Voids in the sintered body can be reduced. Generally, the thermal expansion coefficient of the glass phase made of Al ₂ O ₃ or SiO ₂ is as low as 5 to 6 ppm / ° C. However, when the reaction between SrO and Al ₂ O ₃ or SiO ₂ in the glass proceeds to precipitate a complex oxide such as slausonite, the slausonite has a high thermal expansion characteristic of about 7 ppm / ° C. The thermal expansion coefficient of the whole body can be increased by about 0.5 to 1 ppm / ° C. as compared with the case where SrO is not added. Note that the remaining TiO ₂ plays a role in promoting the crystallization. However, if TiO ₂ itself has a high dielectric constant and remains in a large amount, the dielectric constant of the entire system increases, which is not desirable.

Therefore, when the addition amount of SrO and TiO ₂ is less than 0.1% by weight, the effect of improving sinterability and the effect of reducing voids are small, and the composite oxide crystal containing Sr, Al, and Si has a small effect. It is not produced, and if it exceeds 10% by weight, the dielectric constant becomes high.

B ₂ O ₃ and ZnO are optional components. In particular, sinterability can be improved by adding these components. However, the thermal expansion coefficient between the sintered body weight ZnO exceeds 30% by weight is low, B ₂ O ₃ amount is 1
If the content exceeds 0% by weight, it becomes difficult to form a slurry and a tape due to problems such as dissolution of the component B in the solvent.

Then, a predetermined molded body is prepared using the mixed powder weighed and mixed with the above composition, and the molded body is
It can be manufactured by firing in an oxidizing atmosphere or an inert atmosphere at 0 to 1000 ° C.

Further, in order to manufacture a wiring board having a wiring layer using the above sintered body, using the mixed powder,
A slurry is prepared by mixing using an appropriate organic solvent and a solvent, and the slurry is formed into a sheet by a well-known doctor blade method, calender roll method, rolling method, or press forming method. Then, after forming a through hole as desired in the sheet-like molded body, in the through hole,
A metal paste containing at least one of copper, gold, and silver is filled. Then, a high-frequency line pattern capable of transmitting a high-frequency signal is printed and applied on the surface of the sheet-like molded body using a metal paste by a screen printing method, a gravure printing method, or the like so that the thickness of the wiring layer is 5 to 30 μm. . After that, the plurality of sheet-shaped molded bodies are aligned and laminated and pressed, and then fired in an oxidizing atmosphere or a non-oxidizing atmosphere at 830 to 1000 ° C., whereby a wiring substrate can be manufactured.

On the surface of the wiring board, a semiconductor element is mounted and connected to a wiring layer so that signals can be transmitted. As a connection method, a connection is made by directly mounting on a wiring layer, or wire bonding, TA
The wiring layer and the semiconductor element are connected by a B tape or the like.

Further, a cap made of the same kind of insulating material as the insulating substrate, another insulating material, or a metal having good heat dissipation properties is provided on the surface of the wiring board on which the semiconductor element is mounted, such as glass, resin or brazing material. By bonding with an adhesive, the semiconductor element can be hermetically sealed, whereby a package for housing a semiconductor element can be manufactured.

[0036]

EXAMPLES Two glasses having the following compositions were prepared.

Glass A: SiO ₂ 44% by weight—Al ₂ O
₃ 29% by weight-MgO 11% by weight-ZnO 7% by weight-B
9% by weight of ₂ O ₃ Glass B: 44% by weight of SiO ₂ -26% by weight of Al ₂ O ₃
—MgO 19% by weight—ZnO 1% by weight—B ₂ O ₃ 10% by weight
μm or less silica powder (quartz) and ZnO powder, Sr
TiO ₃ powder and B ₂ O ₃ powder were mixed according to the compositions shown in Tables 1 and 2.

Then, an organic binder, a plasticizer, and toluene are added to the mixture to prepare a slurry, and the slurry is used to have a thickness of 300 by a doctor blade method.
A μm green sheet was prepared. Then, five green sheets are laminated and 100 kg / c at a temperature of 50 ° C.
Thermocompression bonding was performed by applying a pressure of m ² . After debinding the obtained laminate at 700 ° C. in a water vapor-containing / nitrogen atmosphere, it was fired in dry nitrogen under the conditions shown in Tables 1 and 2 to obtain a sintered body for an insulating substrate.

The dielectric constant and dielectric loss of the obtained sintered body were evaluated by the following methods. Dielectric constant and dielectric loss were measured by cutting out a sample of 10 mm in diameter and 5 mm in thickness,
The measurement was performed at Ｇ20 GHz by a dielectric cylinder resonator method using a network analyzer and a synthesized sweeper. In the measurement, a dielectric substrate of a sample was sandwiched between φ50 Cu plate jigs. The dielectric constant and the dielectric loss were calculated from the resonance characteristic of the TE011 mode of the resonator. Also,
A thermal expansion curve from room temperature to 400 ° C. was taken to calculate a thermal expansion coefficient. The measurement results are shown in Tables 1 and 2.

The crystal phase in the sintered body was identified by X-ray diffraction measurement, and the constituent elements in the amorphous phase were identified by EDX.
(TEM) and EPMA, the amount is 1000
Tables 1 and 2 show elements of ppm or more.

Further, for the above green sheet,
After forming via holes and filling with copper paste, copper paste is printed and applied to the wiring pattern on the sheet surface, and on the bottom surface of the lowermost green sheet, an electrode layer that is conductive to the internal wiring layer is formed. Five layers were laminated and fired under the same conditions as described above to produce a 35 mm square, 1.2 mm thick multilayer wiring board.

A ball-shaped terminal made of solder of 90% by weight of Pb and 10% by weight of Sn was attached to the electrode layer of the multilayer wiring board by low melting point solder (37% by weight of Pb-63% by weight of Sn). The ball-shaped terminals were formed on the entire bottom surface of the wiring substrate at a density of 30 terminals per 1 cm ² .

Then, this wiring board is made of a glass-epoxy board and has a coefficient of thermal expansion of 13 at 40 to 800 ° C.
It was mounted on a printed circuit board having a wiring conductor made of copper foil formed on the surface of an insulating substrate at ppm / ° C. The mounting was performed by positioning the wiring conductor on the surface of the printed circuit board and the ball-shaped terminal of the wiring board, and then using the low melting point solder.

The multilayer wiring board mounted on the printed circuit board as described above is mounted at -40.degree.
A maximum of 1,000 cycles were repeated with a 15-minute / 15-minute hold in a thermostat controlled at each temperature of ° C as one cycle. Then, the electric resistance between the wiring conductor of the printed circuit board and the wiring board was measured for each cycle, and the number of cycles until a change in the electric resistance appeared was shown in Tables 1 and 2.

For some of the samples, sintered bodies were prepared and evaluated in the same manner using Al ₂ O ₃ powder and cordierite powder instead of ZnO and SiO ₂ as filler components (Sample No. 8). , 9, 22, 23). In addition, the same evaluation was performed using glass C and glass D having the following compositions instead of the crystallized glasses A and B (samples Nos. 24 to 27).

Glass C: SiO ₂ 10.4% by weight-Al
₂ O ₃ 2.5 wt% -B ₂ O ₃ 45.3 wt% -CaO
35.2 wt% -Na ₂ O6.6 wt% Glass D: SiO ₂ 14 wt% -Al ₂ O ₃ 24.7 wt% -B ₂ O ₃ 22.6 wt% -BaO14.2 wt%
-Li ₂ O12.8 weight% -Na ₂ O11.7% by weight

[0047]

[Table 1]

[0048]

[Table 2]

As is evident from the results shown in Table 1, according to the present invention, a high thermal expansion coefficient having a thermal expansion coefficient of 7 ppm / ° C. or more mainly containing a quartz type crystal phase and a garnitite type crystal phase and containing a slausonite type crystal phase was obtained. Each of the sintered bodies has excellent dielectric properties with a dielectric constant of 6 or less and a dielectric loss of 30 × 10 ⁻⁴ or less at a measurement frequency of 15 to 20 GHz, and a heat cycle test in mounting on a printed circuit board. In each case, no mounting failure occurred on the printed circuit board even after the 1000 cycle test.

On the other hand, in the composition, SiO ₂ −
In the sample No. 1 in which the amount of glass containing Al ₂ O ₃ —MgO—ZnO—B ₂ O ₃ is more than 95% by weight, a thermal expansion coefficient of 7 ppm / ° C. or more is not achieved, and the sample less than 30% by weight is not obtained. In No. 15, sintering at a low temperature was difficult unless a large amount of B ₂ O ₃ was added, and as a result, the liquid phase component was eluted and did not form a sintered body. Further, when the amount of ZnO is 30
In the case of Sample No. 12 in which the content is more than 10% by weight, it was difficult to bake at 1000 ° C. or less, and the coefficient of thermal expansion was low.

Further, Samples No. 1, 7, 8, 9, and 9 to which no SiO ₂ was added or the amount of SiO ₂ was less than 4.9% by weight.
17, 22, and 23 all had low thermal expansion coefficients. Conversely, in sample No. 13 exceeding 40% by weight,
It could not be densified below 1000 ° C. B ₂
In Samples Nos. 14 and 15 in which the O ₃ amount exceeds 10% by weight,
The liquid phase eluted and could not be densified.

[0052] Samples No.8,9,22,23 is is obtained by blending as Al ₂ O ₃ or cordierite as an additive component to the glass, cordierite in the sintered body and Al ₂ O
Crystals such as ₃ precipitated and the coefficient of thermal expansion decreased.

Further, samples Nos. 24 to 27 using glasses C and D containing no MgO or ZnO as the glass tended to have a large dielectric loss.

[0054]

As described in detail above, according to the wiring board of the present invention, the insulating substrate can be fired at a low temperature of 1000 ° C. or lower by forming the insulating substrate from the composite oxide sintered body having a specific crystal phase precipitated. As a result, a wiring layer made of a low-resistance metal such as copper can be formed, and since it has a low dielectric constant and a low dielectric loss in a high-frequency region of 1 GHz or more, a high-frequency signal can be transmitted very favorably without loss. Moreover, since this insulating substrate has a high thermal expansion characteristic, it has excellent heat cycle resistance even when mounted on a motherboard such as a printed circuit board having an insulating substrate containing an organic resin with a brazing material or the like, A highly reliable mounting structure can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining an example of a BGA type semiconductor element housing package using a wiring board of the present invention.

FIG. 2 is a schematic diagram for explaining the structure of a sintered body in the insulating substrate of the present invention.

[Explanation of symbols]

Reference Signs List A Package for storing semiconductor element 1 Insulating substrate 2 Lid 3 Cavity 4 Semiconductor element 5 Wiring layer 6 Connecting electrode 7 Brazing material 8 Ball-shaped terminal B External electric circuit board 9 Insulating substrate 10 Wiring conductor 11 Brazing material Si SiO ₂ crystal phase SP Spinel type crystal phase SL Sr, Al and Si containing crystal phase G Amorphous phase

Claims (7)

[Claims] 1. A wiring board comprising an insulating substrate and a wiring layer on the surface or inside thereof, wherein the insulating substrate comprises:
Including Si, Al, Mg, Zn, Sr and Ti as constituent elements, and as a crystal phase, a SiO ₂ crystal phase;
A composite oxide containing a spinel-type oxide crystal phase containing at least Zn and Al and a composite oxide crystal phase containing at least Sr, Al and Si, and having a thermal expansion coefficient of 7 ppm / ° C. or more from room temperature to 400 ° C. A wiring substrate comprising a sintered body. 2. The wiring board according to claim 1, wherein the SiO ₂ crystal phase is a quartz crystal phase. 3. The wiring board according to claim 1, wherein the composite oxide crystal phase containing at least Sr, Al and Si is monoclinic. 4. The wiring substrate according to claim 3, wherein the composite oxide crystal phase containing at least Sr, Al and Si is a slausonite type crystal phase. 5. The composite oxide sintered body is made of SiO ₂ , Al
30-95% by weight of glass powder containing ₂ O ₃ , MgO, ZnO and B ₂ O ₃ , 4.9-40% by weight of SiO ₂ ,
Composite oxide 0.1 to 10 wt% of SrO and TiO _2,
ZnO0~30 wt%, B ₂ O ₃ after molding a mixture consisting of 0-10% by weight, the wiring board of the fired formed by claim 1, wherein a temperature of 800 to 1000 ° C.. 6. The glass powder contains 40 to 52% by weight of SiO ₂ , 14 to 32% by weight of Al ₂ O _{3, 4 to} 24% by weight of MgO, 1 to 16% by weight of ZnO, and 5 to 15% by weight of B ₂ O _3.
The wiring board according to claim 5, wherein the wiring board has a ratio of: 7. A wiring board having an insulating substrate, a wiring layer provided on or on the surface of the insulating substrate, and connection terminals for connection to an external electric circuit, is formed of an insulating material containing an organic resin. In a mounting structure of a wiring board, the wiring board is mounted on at least an external electric circuit board having a wiring conductor formed on a surface thereof, and a connection terminal of the wiring board is brazed to a wiring conductor of the external electric circuit board. Of the insulating substrate is S
i, Al, Mg, Zn, Sr and Ti as constituent elements, and as a crystal phase, a SiO ₂ crystal phase and a spinel-type oxide crystal phase containing at least Zn and Al;
The mounting of the wiring substrate, comprising a composite oxide sintered body containing at least a composite oxide crystal phase containing Sr, Al and Si and having a thermal expansion coefficient of 7 ppm / ° C. or more from room temperature to 400 ° C. Construction.