JPH11243163A - Wiring board and mounting structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which is low in permittivity and dielectric loss, high in thermal expansion coefficient, and reliably mounted on a printed board, and its mounting structure. SOLUTION: A wiring layer 5 is provided to the surface of an insulating board 1 or inside the board 1, a wiring board A equipped with connection terminals 8 connected to an external electrical circuit board B is placed on the external electric circuit board B, where a wiring conductor 10 is formed on the surface of an insulating board 9 which contains organic resin, and the connecting terminals 8 are brazed to the wiring conductor 10 for mounting, wherein the insulating board 1 is formed of a composite oxide sintered body which has a thermal expansion coefficient of 7 to 17 ppm/ deg.C in a temperature range of a room temperature to 400 deg.C, and is of only SiO2 crystalline phase containing Si, Zn, B, and alkaline metal or a combination of an SiO2 crystalline phase, and a crystalline phase selected from among an oxide crystalline phase group composed of an oxide crystalline phase, which contains alkaline metal and Si, an oxide crystalline phase, containing Zn and Si, and an oxide crystalline phase which contains Zn, alkaline metal, and Si.

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. TECHNICAL FIELD The present invention relates to a wiring board having excellent characteristics in high-frequency applications such as microwaves and millimeter waves, and being mountable with high reliability on an external electric circuit board made of an organic resin such as a printed board, 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. Also,
Recently, with the era of advanced information, the frequency band used has been shifting to higher and higher frequencies.

[0003] In such a high-frequency wiring board which requires transmission of high-frequency signals, in order to transmit high-frequency signals without loss, the resistance of the conductor forming the wiring layer must be small, and the high-frequency region of the insulating substrate must be low. It is required that the dielectric loss at the point is small.

However, conventional high-melting metals such as tungsten and molybdenum have a large conductor resistance, especially 30G.
Since it cannot be used for a high-frequency wiring board in the millimeter wave region of Hz or more, it is necessary to use a low-resistance metal such as copper, silver, or gold instead of these metals.

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 Laid-Open No. 5-298919 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 desired 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-mentioned conventional glass ceramics, high-frequency signals such as microwaves and millimeter waves can be transmitted even if simultaneous firing with low-resistance metals such as copper, silver and gold is possible. It has not been specifically studied as an insulating substrate of a wiring substrate to be used, and most of them have high dielectric loss and do not have sufficiently high frequency characteristics. Also, with respect to the thermal expansion characteristics, the conventional glass ceramic sintered body has a lower coefficient of thermal expansion than the alumina sintered body, and is about 3 to 6 ppm / ° C. Was not reliable for practical use.

Accordingly, the present invention can be fired at a temperature of 1000 ° C. or less so as to enable multilayering using gold, silver, and copper as wiring conductors, has a small dielectric constant and a low dielectric loss tangent in a high frequency region, and has a high thermal expansion. It is an object to provide a wiring board having a coefficient. Another object of the present invention is to provide a mounting structure of a wiring board which can be mounted on an external electric circuit board such as a printed board including an organic resin in an insulating substrate with high reliability.

[0009]

Means for Solving the Problems As a result of diligent studies of the above-mentioned problems, the present inventor found that an insulating substrate in a wiring board was made of an SiO ₂ -based crystal phase such as quartz or the above-mentioned SiO ₂ -based crystal phase and an alkali metal. Oxide crystal phase containing Si,
A composite oxide sintered body having a combination of at least one selected from the group consisting of an oxide crystal phase containing Zn and Si and an oxide crystal phase containing Zn, an alkali metal, and Si as a constituent crystal phase As a result, it has been found that a low dielectric constant and a low dielectric loss can be realized in a high frequency region, and at the same time, a high thermal expansion can be realized.

That is, a wiring board according to the present invention is a wiring board having a wiring layer disposed on the surface or inside of an insulating substrate, wherein the insulating substrate contains Si, Zn, B and an alkali metal; The phase is composed of SiO ₂ -based crystal phase alone, or contains SiO ₂ -based crystal phase, oxide crystal phase containing alkali metal and Si, oxide crystal phase containing Zn and Si, and contains Zn, alkali metal and Si And a composite oxide sintered body having a coefficient of thermal expansion from room temperature to 400 ° C. of 7 to 17 ppm / ° C. while being combined with at least one selected from the group of oxide crystal phases. is there.

The SiO ₂ -based crystal phase is a quartz crystal phase, contains at least Li as the alkali metal, and contains the alkali metal (M) and Si.
Is an oxide crystal phase containing M ₂ Si ₂ O ₅ and M ₂
At least one of SiO ₃ , Z
It is preferable that the oxide crystal phase containing n and Si be a Zn ₂ SiO ₄ crystal phase, and the crystal phase containing Zn, an alkali metal (M) and Si be an M ₂ ZnSiO ₄ crystal phase.

Further, in the composite oxide sintered body, SiO ₂ is contained in an amount of 60 to 98 in terms of oxide conversion of each metal element.
% Of ZnO, 45% by weight or less of ZnO, and 0.2% of B ₂ O ₃ .
5 to 15% by weight and 0.2 to 10% of alkali metal oxide
Composition in a proportion by weight%, or the SiO ₂ 35
0.5 and 98 wt%, and 40 wt% or less ZnO, the glass containing at least SiO ₂ and B ₂ O ₃
It is characterized by being obtained by firing a composition containing 60% by weight and 0.2 to 10% by weight of an alkali metal oxide.

Further, according to the mounting structure of the wiring board of the present invention, the wiring board provided with the wiring layer on the surface or inside of the insulating substrate and provided with the connection terminal to the external electric circuit can be mounted on the insulating substrate containing the organic resin. In a mounting structure of a wiring board, wherein the wiring board is mounted on an external electric circuit board having a wiring conductor formed on the surface of the board and the connection terminals are brazed to the wiring conductor, the wiring board is formed of the specific crystal phase. And a composite oxide sintered body having a thermal expansion coefficient of 7 to 17 ppm / ° C. from room temperature to 400 ° C.

[0014]

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 has, for example, a high frequency signal of 1 GHz or more, particularly 20 GHz or more,
When a high-frequency signal of 0 GHz or more, or even 70 GHz or more, is transmitted, it is necessary to transmit the high-frequency signal without loss. Therefore, well-known strip lines, microstrip lines, coplanar lines, and dielectric waveguides are known. It is composed of at least one of the pipelines. 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.

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.

The mounting structure of the above-mentioned wiring board is shown in FIG.
As shown in FIG. 5, an external electric circuit board B having a conductor wiring 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 through 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 conductor wiring 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. And is mounted.

According to the present invention, in order to improve the reliability of the mounting of the wiring board on the external electric circuit board, the thermal expansion coefficient of the insulating substrate in the wiring board from room temperature to 400 ° C. is 7 ppm / ° C. or more, especially It is important that the content be 9 ppm / ° C. or more, and more preferably 10 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. This is because stress due to the difference in expansion is generated, cracks and the like are generated in the mounting portion, and the reliability of the mounting structure is impaired.

In a surface mount type package which is mounted by brazing with the ball-shaped terminals 8 interposed therebetween, even when the package is mounted on an external electric circuit board made of an insulating substrate containing an organic resin, By setting the coefficient of thermal expansion of the wiring board within the above range, the difference in thermal expansion between the external electric circuit board and the insulating substrate can be made smaller than that of the conventional ceramic material. Also in this case, the generation of stress can be suppressed, so that the long-term reliability of the mounting structure can be improved.

According to the present invention, the insulating substrate of the wiring board is
It is composed of a composite oxide sintered body containing Si, Zn, B and an alkali metal as constituent elements, and the sintered body is densely sintered to a relative density of 95% or more by firing at a low temperature of 800 to 1000 ° C. It is composed of

In the above-mentioned composite oxide sintered body, the constituent crystal phase is composed of a single phase of a SiO ₂ -based crystal phase, or
SiO ₂ -based crystal phase, oxide crystal phase containing alkali metal and Si, oxide crystal phase containing Zn and Si, and Zn
And at least one selected from the group of oxide crystal phases containing alkali metal and Si.

Quartz, cristobalite, tridymite and the like are known as SiO ₂ -based crystal phases. Cristobalite has a bent portion having a coefficient of thermal expansion, and is particularly a quartz crystal phase among these. It is desirable.

The oxide crystal phase containing alkali metal (M) and Si includes M ₂ Si ₂ O ₅ and M ₂ S
Desirably, it is made of at least one of alkali metal silicates such as iO ₃ . Further, the oxide crystal phase containing Zn and Si is desirably composed of a willemite-type crystal phase represented by Zn ₂ SiO ₄ .

The crystal phase containing Zn, the alkali metal (M) and Si is preferably an M ₂ ZnSiO ₄ crystal phase. In addition, Zn and the alkali metal are added to the Si site of the Zn ₂ SiO ₄ type crystal. The crystal phase of Zn ₂ (Znx My Siz) O ₄ (x + y + z = 1) in which (M) is dissolved may be used.

Examples of the combination of two or more SiO ₂ -based crystal phases as constituent crystal phases include a SiO ₂ -based crystal phase and a willemite-type crystal phase represented by Zn ₂ SiO _4. Si, alkali metal and Zn
An oxide crystal phase containing:

Further, a glass phase containing at least Si and B exists at the grain boundaries of these crystal phases.

As described above, according to the present invention, an SiO ₂ -based crystal phase, particularly a quartz crystal phase having a thermal expansion coefficient of 13 to 20 ppm / ° C. at room temperature to 400 ° C., is precipitated in the composite oxide sintered body. Thereby, while having a low dielectric constant of 7 or less, a low loss of 30 × 10 ⁻⁴ or less in a high frequency band such as a microwave and a millimeter wave, specifically, in a range of 1 GHz to 60 GHz. It has characteristics.

In addition, a Zn ₂ SiO ₄ crystal phase having a low thermal expansion characteristic of 1-2 ppm / ° C. or 9-13 pp
m ₂ / ° C Li ₂ SiO ₅ , Li ₂ SiO ₃ , Li ₂ Zn
The presence of a crystalline phase such as SiO ₄ makes it possible to control the thermal expansion characteristics in an arbitrary range. For example, when the amount of SiO ₂ in the total amount is 94% by weight or more, the crystal phase constituting the sintered body is substantially composed of only a quartz crystal phase, and in this case, the dielectric constant is 4.5 or less. From room temperature to 40
The coefficient of thermal expansion at 0 ° C. can be controlled in the range of 15 to 17 ppm / ° C.

According to the first aspect of the composite oxide sintered body constituting the wiring board in the present invention, the content of SiO ₂ is 60 to 98% by weight in terms of oxide conversion of each metal element, and Z is
and 45 wt% or less nO, B ₂ and O ₃ of 0.5 to 15 wt%, is made of a composition containing an alkali metal oxide in a proportion of 0.2 to 10 wt%.

The reason for limiting each component composition to the above range is as follows.
If the content of SiO ₂ is less than 60% by weight in the main component composition, the amount of precipitated SiO ₂ -based crystal phase will be small, and the thermal expansion coefficient will be less than 7 ppm / ° C. If the amount of SiO ₂ is more than 98% by weight, firing at 1000 ° C. or lower becomes impossible. The desirable amount of SiO ₂ is 65 to 95% by weight.

If ZnO is more than 45% by weight, Z
Excessive precipitation of a compound of nO and SiO ₂ (Zn ₂ SiO ₄ ) results in a thermal expansion coefficient of less than 7 ppm / ° C. A desirable amount of ZnO is 15% by weight or less.

If the content of the alkali metal oxide is less than 0.2% by weight, the main phase of SiO ₂ is easily transformed into cristobalite, and the thermal expansion behavior having an inflection point at around 200 ° C. This is because the dielectric loss is deteriorated when the content is more than 10% by weight. A desirable amount of the alkali metal oxide is 0.5 to 5% by weight.

The alkali metal desirably contains at least Li, and furthermore, Li, K, N
Desirably, it is composed of a combination of at least one selected from the group consisting of a, Cs and Rb. This is the L
Due to the synergistic effect with i ₂ O, further lower temperature firing can be realized. When Li is used in combination with an alkali metal other than Li, the amount of the alkali metal other than Li is preferably 0.05 to 5% by weight. Such L
If the amount of the alkali metal other than i is less than 0.05% by weight, no synergistic effect with Li ₂ O is exhibited, and if it is more than 5% by weight, a liquid containing Li, B, Na, etc. at 800 to 850 ° C. This is because the phase components elute.

Further, the B ₂ O _3, the amount of B ₂ O ₃ is less than 0.5 wt%, can not be sufficiently densified ceramic is at a temperature of 800 to 1000 ° C., more than 15 wt% This is because an excessive liquid phase is generated and the dielectric loss in a high frequency range of 1 to 60 GHz exceeds 30 × 10 ⁻⁴ . Preferred range of B ₂ O ₃ is 1 to 5 wt%.

Further, according to the second aspect of the composite oxide sintered body constituting the wiring board in the present invention, SiO ₂ is 35 to 98% by weight in terms of the oxide conversion ratio of each metal element.
When a 40% by weight of ZnO, the glass containing at least SiO ₂ and B ₂ O ₃ 0.5 to 60 wt%
And a composition containing 0.2 to 10% by weight of an alkali metal oxide.

In this composition, the reasons for limiting the upper and lower limits of SiO ₂ , ZnO and the alkali metal oxide are the same as in the first embodiment. At least SiO
₂ and B ₂ O ₃ , when the glass content is less than 0.5% by weight, 800 to 1000 ° C.
If the porcelain cannot be sufficiently densified at a temperature of more than 60% by weight, an excessive liquid phase is generated and the dielectric loss in a high frequency region of 1 to 60 GHz becomes higher than 30 × 10 ^-4. It is. A desirable range of the glass containing at least SiO ₂ and B ₂ O ₃ is ₃ to 20% by weight.

It should be noted that at least the above-mentioned SiO ₂ , B ₂ O
_As glass containing ₃ , generally, borosilicate glass,
Zinc borosilicate glass, although borosilicate lead glass is preferably used, in particular a SiO ₂ 5 to 80 wt%,
Wherein each B ₂ O ₃ in a proportion of 4-50 wt%, the Al ₂ O ₃ 30 wt% or less as another component, are preferably used those containing alkali metal oxides in a proportion of 20 wt% or less, A mixture of these oxide components at a predetermined ratio is melted, cooled and vitrified.

In order to manufacture the composite oxide sintered body constituting the insulating substrate in the present invention, the raw material powder is SiO 2
₂ , oxides of ZnO, B ₂ O ₃ and alkali metals such as Li, K, Na, Cs and Rb, carbonates and nitrates which can form oxides by firing, or two or more of the above oxides Can also be used.

Specifically, as a source of ZnO and SiO ₂ , a willemite compound represented by Zn ₂ SiO ₄ can be used in addition to a simple oxide. In addition, B ₂ O
_{The three} sources include B ₂ O ₃ , B ₂ S ₃ , H ₂ BO ₃ , which can form B ₂ O ₃ in the sintering process, ZnO · 2B ₂ O ₃ ,
At least one is used from the group of compounds such as zinc borate, such as ZnO · 3B ₂ O _3.

Further, as a Li ₂ O source, Li ₂ O, Li ₂ CO ₃ , LiOH which can form Li ₂ O in the sintering process,
・ H ₂ O, Li ₂ S, etc., or Li ₂ SiO ₃ , Li
₄ SiO ₄ , Li ₂ Si ₂ O ₅ , Li ₂ Si ₃ O ₇ , L
SiO ₂ and Li such as i ₆ Si ₂ O ₇ and Li ₈ SiO ₆
Compounds with ₂ O, Li ₂ ZnSiO ₄ , Zn ₂ (Znx
LiySiz) SiO ₂ such as O ₄ (x + y + z = 1)
At least one is used selected from the group consisting of a composite oxide of Li ₂ O and ZnO and.

As the at least one oxide source selected from the group consisting of K, Na, Cs and Rb, oxides of respective metal elements, carbonates and nitrates which can form oxides by firing are used. Is done.

Furthermore, at least SiO ₂ and B
_As the glass containing ₂ O ₃ , borosilicate-based glass, zinc borosilicate-based glass, lead borosilicate-based glass, and the like are preferably used as described above.

Using these raw materials, the composition of the first embodiment or the second embodiment is prepared and mixed. And
After appropriately adding a binder to the mixed powder, for example,
After being formed into an arbitrary shape by a mold press, a cold isostatic press, an extrusion molding, a doctor blade method, a rolling method, or the like, 800 ° C. to 1000 ° C. in an oxidizing atmosphere or a non-oxidizing atmosphere such as N ₂ or Ar. Calcination at a temperature of 850 to 950 ° C. for 0.1 to 5 hours to give a relative density of 95%
It can be densified as described above.

If the firing temperature at this time is lower than 800 ° C.,
The porcelain is not sufficiently densified. If the temperature exceeds 1000 ° C., densification is possible, but simultaneous sintering with a conductor such as copper or silver cannot be performed. Incidentally, at the time of simultaneous firing, it is necessary to fire in a non-oxidizing atmosphere when copper is used as the conductor and in a non-oxidizing or oxidizing atmosphere when using silver as the conductor.
This is because a copper conductor cannot be used.

In the above method for producing a sintered body,
Before performing the molding process, the predetermined mixed powder is
By calcining for about 1 to 3 hours in an oxidizing atmosphere at a temperature of about 1 ° C., and pulverizing it, the sinterability is improved because the components and powders are homogenized, and the calcining temperature is reduced. It is possible to lower the temperature by about 50 ° C. as compared with the case where there is none.

According to the above manufacturing method, Zn and Si
And B ₂ O ₃ or SiO ₂ , B
A glass containing ₂ O _3, and further Li ₂ O, K, Na,
By adding a combination of at least one oxide selected from the group consisting of Cs and Rb, a liquid phase mainly composed of Zn generated from the composite oxide and B (boron) in B ₂ O ₃ or glass A more active liquid phase reaction of the components occurs. Further, by combining Li with at least one oxide selected from the group consisting of K, Na, Cs and Rb, a liquid phase is generated at a lower temperature by an alkali mixing effect, so that the alkali metal element is a kind of an alkali metal element. As compared with the case, a liquid phase is generated at a low temperature, and as a result, sintering can be performed at a temperature of 800 to 1000 ° C. or less by adding a small amount of additive, and the porcelain can be densified. Therefore, the amount of the amorphous phase at the grain boundary, which causes an increase in dielectric loss, can be minimized. Therefore, a lower dielectric loss can be obtained in a high frequency band.

The insulating substrate of the present invention has a thickness of 800
Since it can be fired at ~ 1000 ° C, especially copper, gold,
It can be used as an insulating substrate of a wiring board for wiring silver or the like. In the case of manufacturing a wiring board using such a sintered body, for example, after the mixed powder prepared as described above is calcined if desired, a known tape forming method,
For example, according to a doctor blade method, a rolling method, etc., after producing a green sheet for forming an insulating layer, for the wiring circuit layer on the surface of the sheet, copper, at least one metal of gold and silver, especially copper Using a conductive paste containing powder, the wiring pattern is printed on the surface of the green sheet in a circuit pattern by screen printing, gravure printing, or the like, and in some cases, the sheet is filled with the conductive paste after forming through holes or via holes. . Thereafter, a plurality of green sheets are stacked and pressed, and then fired under the above-described conditions, whereby the wiring layer and the insulating substrate are simultaneously fired, whereby a wiring substrate can be manufactured.

On the bottom surface of the wiring board, connection terminals for connection to an external electric circuit board are attached by brazing or the like. For example, in the case of a BGA type package,
A ball-shaped terminal made of low-melting-point solder or high-melting-point solder is attached to a connection pad formed on the bottom surface of the wiring board by low-melting-point solder.

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, connection can be made by directly mounting on the wiring layer, wire bonding, TA, or the like.
B tape or the like is employed.

Thereafter, as shown in FIG. 1, the lid is brazed and the semiconductor element is hermetically sealed therein. Further, a semiconductor device is completed. In order to connect this semiconductor device to the external electric circuit board, the wiring conductors on the surface of the external electric circuit board and the connection terminals of the wiring board may be mounted with a brazing material such as solder.

[0051]

EXAMPLES Example 1 Zn ₂ SiO ₄ powder having an average particle size of 1 μm or less, ZnO.
Compounds represented by 2B ₂ O ₃ powder or 4ZnO · 3B ₂ O ₃ powder, molten SiO ₂ (amorphous), and powders of carbonates of various alkali metals were used as raw materials. Mix according to composition. And
This mixture was calcined at 750 ° C. for 1 hour in the air, and then pulverized. An organic binder, a plasticizer, and toluene were added to the processed product, and a green sheet having a thickness of 300 μm was prepared by a doctor blade method. Then, five green sheets are laminated, and at a temperature of 50 ° C., 100 k
g / cm ² and a thermocompression bonding. After debinding the obtained laminate in a steam-containing nitrogen atmosphere at 700 ° C., it was fired in dry nitrogen under the conditions shown in Tables 1 and 2 to obtain a sintered body for a multilayer wiring board.

As comparative examples, MgSiO ₃ , Ca
A sintered body was prepared and evaluated in the same manner by adding SiO ₂ as a main component, adding a B ₂ O ₃ -containing compound and an alkali metal oxide thereto, and evaluating the same (Samples Nos. 27 and 28).

The dielectric constant and dielectric loss of each of the obtained sintered bodies were evaluated by the following methods. The measurement is 1-5m in shape diameter
A sample having a thickness of m and a thickness of 2 to 3 mm was cut out and subjected to a dielectric cylinder resonator method at 60 GHz using a network analyzer and a synthesized sweeper. In the measurement,
The dielectric resonator was excited by an NRD guide (non-radiative dielectric line), and the dielectric constant and dielectric loss were calculated from the resonance characteristics of the TE021 and TE031 modes. The results of the measurement are shown in Tables 1 and 2. In addition, for each sintered body, 4
The coefficient of thermal expansion in the temperature range of 00 ° C. was measured.

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 90% by weight of Pb-10% by weight of Sn was attached to the electrode layer of this 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 thermal expansion coefficient 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.

[0058]

[Table 1]

[0059]

[Table 2]

As is clear from the results of Tables 1 and 2, the present invention in which a quartz-type crystal phase, a quartz-type crystal phase, and a willemite-type crystal phase (Zn ₂ SiO ₄ ) (W) mainly precipitated as the crystal phase. Porcelain has a dielectric constant of 7
Hereinafter, the dielectric loss at 60 GHz was 30 × 10 ⁻⁴ or less, and the coefficient of thermal expansion was 7 to 17 ppm / ° C.
The liquid phase of the porcelain of the present invention was analyzed by ICP emission spectroscopy.
And other trace amounts of Si, B, Li, Na, etc. were detected.

Further, the thermal expansion coefficient of the insulating substrate is 7 to 17p.
Each of the samples formed of the pm / ° C. sintered body showed excellent durability of 1000 cycles or more in the thermal cycle test.

On the other hand, in Sample No. 7 in which the amount of SiO ₂ exceeds 98% by weight, densification cannot be performed unless the temperature is raised to 1400 ° C., and in Samples No. 19 and 21 less than 60% by weight, the coefficient of thermal expansion is Was small and did not meet the purpose of the present invention. Sample N in which the amount of B ₂ O ₃ is less than 0.5% by weight
In the case of o.17, densification could not be achieved unless the firing temperature was increased to 1200 ° C., which was not suitable for the purpose of the present invention. On the other hand, the sample No. having a B ₂ O ₃ amount exceeding 15% by weight.
In No. 20, the liquid phase eluted. 0.2 alkali metal
In the sample No. 13 having less than the weight%, cristobalite was precipitated in a large amount, the coefficient of thermal expansion exceeded 17 ppm / ° C., which was not suitable for the purpose of the present invention, and an inflection point occurred in the thermal expansion curve. In Samples Nos. 11 and 16 in which the amount of alkali metal was more than 10% by weight, the liquid phase eluted.

As comparative examples, MgSiO ₃ and Ca
In Samples Nos. 25 and 26 using SiO ₃ , if the amount of B ₂ O ₃ was not more than 15% by weight, densification would not be achieved, and sufficient dielectric properties could not be obtained, which was not suitable for the purpose of the present invention. .

Example 2 For Zn ₂ SiO ₄ having an average particle size of 1 μm or less, Table 3
Glass powder having the following composition and, further, carbonates of various alkali metals, and in some cases, molten SiO ₂ were added, and mixed such that the amounts of SiO ₂ , ZnO and alkali metal oxides other than the added glass became the compositions shown in Table 3. did. The mixture was calcined at 700 ° C. for 1 hour in an air atmosphere, and then pulverized. An organic binder, a plasticizer, and toluene were added to the processed product, and a green sheet having a thickness of 300 μm was prepared by a doctor blade method. Then, five green sheets are laminated, and 100
Thermocompression bonding was performed by applying a pressure of kg / cm 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 Table 3 to obtain a composite oxide sintered body for a multilayer substrate.

In the same manner as in Example 1, the obtained sintered body was measured for dielectric constant, dielectric loss and identification of crystal phase, thermal expansion coefficient, and thermal cycle test in the same manner as in Example 1. The results of the measurement are shown in Tables 4 and 5.

[0066]

[Table 3]

[0067]

[Table 4]

[0068]

[Table 5]

As is evident from the results of Tables 4 and 5, according to the present invention, the sintered body in which a quartz-type crystal phase or a willemite-type crystal phase mainly precipitated as a crystal phase has a dielectric constant of 7 or less. Dielectric loss at 60 GHz is 30 × 10
^-4 shows excellent value below, thermal expansion coefficient is 7 ~ 17ppm
The sintered body at / ° C also exhibited excellent durability in a heat cycle test.

[0070]

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.

[Description of Signs] A BGA type package 1 Insulating substrate 2 Lid 3 Cavity 4 Semiconductor element 5 Wiring layer 6 Connection electrode layer 7 Brazing material 8 Ball-shaped terminal B External electric circuit board 9 Insulating substrate 10 Conductor wiring 11 Brazing material

Claims (9)

[Claims] 1. A wiring board having a wiring layer disposed on the surface or inside of an insulating substrate.
Including i, Zn, B and an alkali metal, the constituent crystal phase is composed solely of a SiO ₂ -based crystal phase, or an SiO ₂ -based crystal phase, an oxide crystal phase containing an alkali metal and Si, and including Zn and Si It is composed of a combination of an oxide crystal phase and at least one selected from the group of oxide crystal phases containing Zn, an alkali metal and Si, and has a coefficient of thermal expansion from room temperature to 400 ° C. of 7 to 17 ppm / ° C.
A wiring substrate comprising a composite oxide sintered body of the above. 2. The wiring board according to claim 1, wherein said SiO ₂ -based crystal phase is a quartz crystal phase. 3. The method according to claim 1, wherein the alkali metal is at least Li.
The wiring board according to claim 1, further comprising: 4. The wiring substrate according to claim 1, wherein the oxide crystal phase containing the alkali metal (M) and Si comprises at least one compound of M ₂ Si ₂ O ₅ and M ₂ SiO _3. . 5. The oxide crystal phase containing Zn and Si is Z
_2. The wiring board according to claim 1, comprising a compound represented by n ₂ SiO ₄ . 6. The wiring board according to claim 1, wherein the crystal phase containing Zn, the alkali metal (M) and Si is a compound represented by M ₂ ZnSiO ₄ . 7. The composite oxide sintered body contains 60 to 98% by weight of SiO _{2 in} terms of an oxide conversion of each metal element.
And 45 wt% or less ZnO, B ₂ and O ₃ of 0.5 to 15 wt.%, Is obtained by firing a composition containing an alkali metal oxide in a proportion of 0.2 to 10 wt% Claim 1
The wiring board as described. 8. The composite oxide sintered body contains 35 to 98% by weight of SiO _{2 in} a ratio of each metal element in terms of oxide.
When a 40% by weight of ZnO, the glass containing at least SiO ₂ and B ₂ O ₃ 0.5 to 60 wt%
2. The wiring board according to claim 1, wherein the composition is obtained by firing a composition containing 0.2 to 10% by weight of an alkali metal oxide. 9. A wiring board provided with a wiring layer on the surface or inside of an insulating substrate and having a connection terminal to an external electric circuit is replaced with an external board having a wiring conductor formed on the surface of an insulating substrate containing an organic resin. In a mounting structure of a wiring board, which is mounted on an electric circuit board and the connection terminals are brazed to the wiring conductor, the insulating substrate of the wiring board may be made of Si, Z
n, B and an alkali metal, and the constituent crystal phase is SiO
_{It is} composed of a _2- system crystal phase alone or an SiO ₂ system crystal phase, an oxide crystal phase containing an alkali metal and Si, Zn
And a combination of at least one selected from the group consisting of an oxide crystal phase containing Si and an oxide crystal phase containing Zn, an alkali metal, and Si,
A mounting structure for a wiring board, comprising a composite oxide sintered body having a coefficient of thermal expansion at 0 ° C. of 7 to 17 ppm / ° C.