JP3466561B2 - Low temperature fired porcelain composition, low temperature fired porcelain, and wiring board using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low temperature fired porcelain composition, a low temperature fired porcelain, and a wiring board using the porcelain as an insulating substrate. More specifically, the invention relates to a metallized wiring layer made of a metal such as Cu or Ag. The present invention relates to improvement of a sintered body suitable for an insulating substrate of a wiring board which can be formed, has a high coefficient of thermal expansion, is mounted with a semiconductor element or the like, and has excellent mounting reliability with an external circuit board such as a printed board.

[0002]

2. Description of the Related Art Generally, a wiring board used for electronic equipment has a structure in which a metallized wiring layer is provided on the surface or inside of an insulating substrate. Further, as a typical example of a circuit device using such a wiring board, a semiconductor element, particularly an LSI
An example is a semiconductor element housing package that houses a semiconductor integrated circuit element such as (large-scale integrated circuit element).

This package for accommodating semiconductor elements is generally made of an electrically insulating material such as alumina sintered body, and has an insulating substrate on which a semiconductor element is mounted at the center of the upper surface thereof, and is connected to the semiconductor element from the periphery of the element to the lower surface thereof. A plurality of metallized wiring layers that are derived from a refractory metal such as tungsten and molybdenum, a plurality of connection terminals that are electrically connected to the metallized wiring layers formed on the side surface or the lower surface of the insulating substrate, and a lid body. It is formed by joining a lid to the upper surface of the insulating substrate via a sealing material such as glass or resin, and hermetically sealing the semiconductor inside the container including the insulating substrate and the lid.

As an insulating substrate used for a package for housing a semiconductor element, a sintered body such as alumina or mullite has been used so far, but recently, it can be sintered at a low temperature and has a low resistance as a wiring layer. Various insulating substrates made of low-temperature fired porcelain that can use Cu, Ag, and the like have been proposed. For example, Japanese Patent Publication No. 4-114995 and Japanese Patent Publication No. 6-7.
No. 6253 and the like include SiO ₂ —BaO—Al ₂ O ₃ —B ₂ O.
A porcelain composition containing ₃ and capable of firing at 1050 ° C. or lower has been proposed, and it is described that the dielectric constant can be reduced as compared with an alumina-based porcelain.

[0005]

However, in the low temperature fired porcelain disclosed in Japanese Examined Patent Publication No. 4-11495 and Japanese Examined Patent Publication No. 6-76253, the coefficient of thermal expansion of the porcelain is low, and when it is used as an insulating substrate. Has a problem that mounting reliability decreases when it is mounted on an external circuit board such as a printed circuit board. Also, the metallized wiring layer formed on the surface of the porcelain forming the insulating board contracts from a temperature lower than that of the porcelain during firing. In addition, there is a problem that the insulating substrate after firing is warped.

The present invention has been made to solve the above problems, and its purpose is to enable firing at 1050 ° C. or lower, to increase the thermal expansion coefficient of porcelain, and to form a metallized wiring layer. Another object of the present invention is to obtain a low-temperature fired porcelain composition, a low-temperature fired porcelain, and a wiring board using the same, which can produce an insulating substrate that does not warp even by simultaneous firing.

[0007]

Means for Solving the Problems The inventors of the present invention have made extensive studies on the above problems, and as a result, in the total amount, Si is 40 to 70% by weight in terms of SiO ₂ and Ba is 15 to 5 in terms of BaO.
0% by weight, B is 1 to 5% by weight in terms of B ₂ O ₃ , Al is 1 to 8% by weight in terms of Al ₂ O ₃ , and rare earth element (RE) is 0% by weight in terms of RE ₂ O _3. A composition containing more than 5% by weight of the composition, wherein the composition contains a quartz crystal in an amount of 30% by weight or more, the thermal expansion coefficient of the porcelain is improved. It has been found that it is possible to fabricate an insulating substrate that can be made higher to be closer to an external circuit board and that does not warp even when co-firing with a metallized wiring layer.

Further, according to the present invention, a barium silicate crystal is further contained, and the ratio of the content of the crystal phase (a% by weight) to the content of the amorphous phase (b% by weight) (a / ( a +
It is desirable that b)) × 100 (%) is 80% or more.

Furthermore, the low temperature fired porcelain of the present invention comprises the above low temperature fired porcelain composition and has an open porosity of 2% or less, 40 to 40%.
The thermal expansion coefficient at 400 ° C. is 9 to 18 × 10 ⁻⁶ / ° C.

Further, the wiring board of the present invention is a wiring board in which a metallized wiring layer is provided on the surface and / or inside of an insulating substrate, wherein the insulating substrate is composed of the low temperature fired porcelain, The amount of warpage on the surface of the insulating substrate on which the wiring layer is formed is 0.4% or less, and it is particularly preferable that the metallized wiring layer mainly contains copper or silver.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The low temperature fired porcelain composition of the present invention comprises:
In the total amount, Si is 40 to 70% by weight in terms of SiO ₂ , and B
a is 15 to 40% by weight in terms of BaO, B is 1 to 5% by weight in terms of B ₂ O ₃ , and Al is 1 to 8% by weight in terms of Al ₂ O _3.
And a rare earth element (RE) in an amount of more than 0% by weight and 5% by weight or less in terms of RE ₂ O ₃ .

If the amount of SiO ₂ is less than 40% by weight, the coefficient of thermal expansion of the porcelain cannot be increased. Conversely, if the amount of SiO ₂ is more than 70% by weight, 1050 ° C
By the following firing, the porosity of the porcelain cannot be reduced to 3% or less, and the thermal expansion coefficient, water resistance, chemical resistance, strength and the like are deteriorated. The desirable range of the amount of SiO ₂ is 50 to 65
% By weight, 55-60% by weight, in particular 56-59% by weight.

When the amount of BaO is less than 15% by weight, the porosity of the porcelain is 3% by firing at 1050 ° C or lower.
In addition, the amount of warpage of the insulating substrate cannot be controlled within a predetermined range when the shrinkage starting temperature of the porcelain becomes high and the metallized wiring layer is fired at the same time. On the contrary, if the amount of BaO is more than 50% by weight, it is impossible to satisfy both the densification of the porcelain and the improvement of the thermal expansion coefficient at the same time. The desirable range of the amount of BaO is 25 to
35% by weight.

Further, when the amount of B ₂ O ₃ is less than 1% by weight, the porosity of the porcelain cannot be reduced by firing at 1050 ° C. or less, and the shrinkage start temperature of the porcelain becomes high, so that the metallized wiring layer is formed. When co-firing with, the amount of warpage of the insulating substrate cannot be controlled within a predetermined range. B ₂ O ₃
This is because if the amount is more than 5% by weight, the strength is lowered and the strength of the porcelain is greatly lowered by the heat cycle. The desirable range of the amount of B ₂ O ₃ is 1.5 to 3% by weight.

If the amount of Al ₂ O ₃ is less than 1% by weight, the strength of the porcelain decreases, the rate of decrease in strength after thermal cycling increases, and the chemical resistance of the porcelain deteriorates. May be eroded from the surface. On the other hand, if the amount of Al ₂ O ₃ is more than 8% by weight, the porosity of the porcelain cannot be reduced by firing at 1050 ° C. or less,
Moreover, when the shrinkage start temperature of the porcelain becomes high and the metalized wiring layer is co-fired, the amount of warpage of the insulating substrate cannot be controlled within a predetermined range. The desirable range of the amount of Al ₂ O ₃ is 4 to 8% by weight.

Further, if RE ₂ O ₃ is not contained, the amount of warpage of the insulating substrate cannot be kept within a predetermined range due to the mismatch of firing shrinkage behavior when co-firing with the metallized wiring layer, and the warpage of the wiring substrate is prevented. This causes a decrease in the initial mounting yield when a semiconductor element, a passive element, or an external circuit board such as a printed board is mounted. On the contrary, if the RE ₂ O ₃ content exceeds 5% by weight, 1050
The porcelain cannot be densified at a temperature of ℃ or less, and the binding force with the quartz crystal is reduced. RE ₂ O ₃ content of desirable range 0.005 to 2.0% by weight, in particular 0.01 to 1.0
% By weight. The rare earth element (R
E) means Y, Yb, La, Ce, Pr, Nd, Pm,
Eu, Sm, Gd, Tb, Dy, Ho, Er, Tm, L
It means at least one selected from the group of u, and it is particularly desirable to contain Y (yttrium) which has a high effect of approximating the cost and firing behavior to the metallized wiring layer.

In addition to the above components, 7% by weight of ZrO ₂ is added in order to enhance the chemical resistance of the porcelain and enhance the compatibility with the quartz present in the porcelain to enhance the porcelain strength.
It is desirable to contain it in the following range.

Furthermore, according to the present invention, in addition to the above-mentioned components, Ca is 10% by weight or less, especially 5% by weight in terms of CaO.
Hereafter, 2% by weight or less, Mg in terms of MgO of 10% by weight or less, particularly 5% by weight or less, further 2% by weight or less, Y
May be contained in an amount of 10% by weight or less, particularly 5% by weight or less, and further 2% by weight or less in terms of Y ₂ O ₃ , and these components reduce the porosity of the porcelain and , Acts to accelerate the crystallization by reducing the ratio of the amorphous phase in the porcelain.

Further, according to the present invention, each component is contained in the above proportions, and 3 parts of quartz crystal are contained in the composition.
0% by weight or more, especially 35% by weight or more, and further 40% by weight
It is a great feature that the content is contained in the above proportion, whereby the coefficient of thermal expansion of the porcelain can be increased and the dielectric loss in the high frequency band can be reduced. That is, when the content of the quartz crystal is less than 30% by weight, the coefficient of thermal expansion of the porcelain at 40 to 400 ° C. is 9 ×.
The temperature is lower than 10 ⁻⁶ / ° C., and due to the difference in thermal expansion between the insulating substrate and the external circuit substrate, the reliability of electrical connection in the (secondary) mounting portion is reduced.

In the above composition, in order to increase the coefficient of thermal expansion of the porcelain and reduce the dielectric loss in the high frequency band,
Barium silicate crystals, especially 10 wt% or more, further 30
It is desirable that the content is at least 40% by weight, more preferably at least 40% by weight. The content ratio of each crystal in the present invention is calculated by the Rietveld method (see Fujio Izumi et al., Journal of the Crystallographic Society of Japan 34 (1992) 76, etc.) based on the peak intensity of each crystal from X-ray diffraction measurement of porcelain. Refers to a value.

As barium silicate, BaO.2S
iO ₂ (di barium silicate) or BaO · SiO ₂ (meth barium silicate) and the like, in particular stably exist BaO · 2SiO ₂ in terms of increasing the coefficient of thermal expansion (di barium silicate)
It is desirable to include. Furthermore, BaO / Si
O ₂ (barium metasilicate) can enhance strength and toughness as long as it is a needle crystal.

Further, in the above composition, other crystalline phases are included.
As celsian (BaO ・ Al ₂O₃・ 2Si
O₂) 2BaO ・ MgO ・ 2SiO₂, Spinel (Mg
O ・ Al₂O₃), Forsterite (2MgO ・ SiO)
₂), Enstatite (MgO / SiO)₂), Wollast
Night (CaO / SiO₂), Monticella Knight (C
aO ・ MgO ・ SiO₂), Diopside (CaO ・
MgO / 2SiO₂), Merbinite (2CaO ・ Mg
O ・ 2SiO₂), Akermite (2CaO ・ MgO ・
2 SiO₂), CaZrO₃, Alumina, cristobaray
Tori, Tridymite, ZrO₂, MgO, petalite, etc.
The total amount of other crystals is 40% by weight or less, particularly 30% by weight or less.
Below 20% by weight, and even below 10% by weight
You may make it contain in a ratio. Above all, increase the toughness of porcelain
In order to achieve a needle-like celsian with an average aspect ratio of 3 or more
(BaO ・ Al₂O₃・ 2SiO₂) Is included
Is desirable.

Further, in terms of the coefficient of thermal expansion, strength, chemical resistance, water resistance and thermal conductivity of the porcelain, the open porosity in the porcelain is 2%.
It is desirable that the content of the crystal (total amount) (a weight%) and the content of the amorphous phase (b) are particularly preferably 1.5% or less.
Ratio (a / (a + b)) × 100 (%) of weight%) is 80
% Or more, particularly 90% or more, and further preferably 95% or more.

The porcelain of the above embodiment has an average (linear) coefficient of thermal expansion at 40 to 400 ° C. of 9 to 18 × 10 ⁻⁶ / ° C., particularly 11 to 14 × 10 ⁻⁶ / ° C. The strength of this porcelain is 160 MPa or more, especially 170 MPa or more, 1 MHz.
Dielectric constant of 7 or less, particularly 6.5 or less, and further 6 or less, 3
Dielectric loss at GHz is less than 30 × 10 ^-4 , especially 25 × 1
0 ^-4 or less, fracture toughness 1.4 GPa or more, especially 1.5 G
It is preferably Pa or more. In terms of bending strength, chemical resistance, water resistance, thermal conductivity, and insulation resistance, it is desirable that the relative density of the porcelain be 90% or more, particularly 95% or more, and further 98% or more.

(Manufacturing Method) On the other hand, in order to manufacture the above-mentioned low temperature fired porcelain of the present invention, the above Si, Ba, B, Al,
The starting material is not particularly limited as long as the rare earth element (RE) is contained in the above ratio, but it is particularly preferable to use a mixture of glass and a filler because of easy crystal control. As the glass component, for example, an average particle size of 0.5 to 1
0 μm zinc borosilicate glass, lead borosilicate glass, lithium silicate glass, PbO glass, ZnO glass, BaO glass, etc. are used. It is desirable to use BaO-based crystallized glass capable of precipitating barium silicate.

The specific composition of the BaO glass is, for example, S in terms of low temperature firing and improvement of crystallinity.
10 to 70% by weight of io ₂ , especially 15 to 30% by weight, Ba
O 30-70% by weight, especially 40-70% by weight, Al ₂ O ₃
8 to 16% by weight, particularly 8.5 to 12% by weight, B ₂ O ₃ 1 to
10% by weight, especially 3-7% by weight, CaO 1-5% by weight,
In particular, glass containing 1 to 3% by weight, RE ₂ O ₃ 0.01 to 5% by weight, and particularly 0.03 to ₃ % by weight is desirable. Furthermore, in the glass having the above composition, an alkaline earth metal oxide other than BaO, an alkali metal oxide, ZrO ₂ , S
b ₂ O ₃ and Bi ₂ O ₃ in a total amount of 5% by weight or less, especially 3% by weight
It may be included in the following ratio.

In addition to the above glasses or in addition to the above glasses, lithium silicate glass, PbO glass, Zn
It is also possible to use O-based glass, zinc borosilicate-based glass, lead borosilicate-based glass, and add barium silicate crystals or the like as a ceramic filler.

Lithium silicate type glass includes Li₂O
5 to 30% by weight, especially 5 to 20% by weight
Lithium having a high coefficient of thermal expansion after firing
Those that precipitate silicic acid are preferably used. Also above
Lithium silicate glass is Li₂SiO other than O₂
Is included as an essential component, but SiO₂Is the total amount of glass,
It is present in the proportion of 60-85% by weight,₂And Li₂O and
Of 65 to 95% by weight in the total amount of glass
It is desirable for precipitating lithium silicic acid crystals. Also, this
In addition to these components, Al₂O₃, MgO, TiO₂, B₂O
₃, Na₂O, K ₂O, P₂O_Five, ZnO, RE₂O₃, F, etc.
May be blended.

The PbO-based glass contains PbO as a main component and further contains at least one of B ₂ O ₃ and SiO ₂ , and after firing PbSiO ₃ and PbZ.
A material in which a high thermal expansion crystal phase such as nSiO ₄ is deposited is preferably used.

As the ZnO-based glass, 10 layers of ZnO are used.
% O or more, and ZnO.Al after firing₂
O₃, ZnO / nB₂O₃Crystal phase with high thermal expansion coefficient such as
Those that come out are preferably used. In addition to ZnO component, S
iO₂(60% by weight or less), Al₂O₃(60% by weight or less
Bottom), B₂O₃(30% by weight or less), P₂O_Five(50% by weight
Below), alkaline earth oxides (20% by weight or less), Bi
₂O₃(30 wt% or less), rare earth element oxide (5 wt%
The following) and the like may be blended. Especially ZnO10
~ 50 wt% -Al₂O₃10-30% by weight-SiO₂Three
0 to 60% by weight of crystalline glass or ZnO 10 to 5
0 wt% -SiO₂5-40 wt% -Al₂O ₃0-15
% By weight-BaO 0-60% by weight-MgO 0-35% by weight
-RE₂O₃A crystalline glass consisting of 0-5% by weight is desired.
Yes.

On the other hand, in order to allow the quartz crystal to be contained in the porcelain by firing at 1050 ° C. or lower, it is desirable to contain quartz as an essential filler component.
Powders of barium silicate, BaO, BaCO _{3 and the} like can be added. In order to convert BaO to barium silicate, other fillers such as amorphous SiO ₂ , cristobalite, tridymite, and other SiO ₂ -based fillers are added in addition to quartz to form BaO and SiO ₂
It is possible to generate and precipitate barium silicate by reacting with. The average particle size of the filler is 0.2 to 15 μm,
It is particularly desirable that the thickness is 0.5 to 10 μm.

Other than the above, other filler components include Al ₂ O ₃ , MgO, ZrO ₂ , forsterite (2MgO.SiO ₂ ), spinel (MgO, Al).
₂ O ₃ ), wollastonite (CaO · SiO ₂ ), monticeranite (CaO · MgO · SiO ₂ ), nepheline (Na ₂ O · Al ₂ O ₃ · SiO ₂ ), lithium silicate (Li ₂ O / SiO ₂ ). ₂ ), diopside (CaO ・
MgO ・ 2SiO ₂ ), merbinite (2CaO ・ Mg
O ・ 2SiO ₂ ), akermite (2CaO ・ MgO ・
2SiO ₂ ), carnegieite (Na ₂ O ・ Al ₂ O ₃・ 2)
SiO ₂ ), enstatite (MgO · SiO ₂ ), magnesium borate (2MgO · B ₂ O ₃ ), celsian (B
aO ・ Al ₂ O ₃・ 2SiO ₂ ), B ₂ O ₃・ 2MgO ・ 2
SiO ₂ , garnite (ZnO ・ Al ₂ O ₃ ), CaTi
Other ceramic fillers such as O ₃ , BaTiO ₃ , SrTiO ₃ and TiO ₂ may be added in a total amount of 20% by weight or less, particularly 10% by weight or less.

By combining the above-mentioned glass and filler, Si, Ba, B, Al, rare earth elements (R
E) may be adjusted so as to have the above-mentioned ratio. For example, these glass and ceramic fillers may contain 10 to 90% by weight of glass, particularly 20 to 80% by weight, and further 30 to 70% by weight, and a filler. It is desirable that it is blended in a proportion of 10 to 90% by weight, particularly 20 to 80% by weight, and further 30 to 70% by weight, in order to enhance the low temperature sinterability and the strength of the sintered body.

After adding an organic resin binder for proper molding to the mixture of the glass component and the filler component consisting of the above-mentioned components, a desired molding means,
For example, a die press, a cold isostatic press, an injection molding, an extrusion molding, a doctor blade method, a calender roll method, a rolling method or the like is used to form an arbitrary shape.

Next, in firing the above-mentioned molded body,
First, the binder component blended for molding is removed. The binder is removed in the air or a nitrogen atmosphere at about 700 ° C., but as a wiring conductor layer, for example, C
When u is used, it is performed in a nitrogen atmosphere containing water vapor at 100 to 700 ° C. At this time, the shrinkage starting temperature of the molded body is preferably 700 to 850 ° C.,
If the shrinkage starting temperature is lower than this, it becomes difficult to remove the binder.

The firing is carried out in an oxidizing atmosphere or a non-oxidizing atmosphere, and in particular enhances the crystallinity of the glass in the porcelain,
The porosity in the porcelain is reduced, and the softening behavior of the glass is reduced by C even when co-firing with the copper wiring conductor layer.
In order to approximate the u conductor layer and suppress the warpage of the insulating substrate, the temperature rising rate is 20 to 350 ° C./hr, particularly 50 to 250.
℃ / hr, further 50 ~ 100 ℃ / hr, firing temperature 8
00-1050 ° C, especially 850-970 ° C, and further 92
At 0 to 950 ° C, 0.5 to 5 hours, especially 1.5 to 3 hours
By firing r, the porcelain can be densified and the low temperature fired porcelain of the present invention can be manufactured.

If the firing temperature at this time exceeds 1050 ° C., the conductor layer will be melted by simultaneous firing with the wiring conductor layer such as Cu or Ag. When firing with a wiring conductor such as Cu, firing may be performed in a non-oxidizing atmosphere.

In addition to the quartz crystal, the porcelain thus produced contains in advance a crystal phase formed from the glass component, a crystal phase formed by the reaction between the glass component and the filler component, or a filler component. In some cases, there is a crystalline phase, or a crystalline phase generated by decomposition or transformation of the filler component, and a glass phase is present in the grain boundaries of these crystalline phases, but the (total) content of the crystals (a weight %) And the content of the amorphous phase (b% by weight) (a / (a
+ B)) × 100 (%) is 80% or more, particularly 90% or more, and further 95% or more improves the thermal expansion coefficient,
It is desirable in terms of improvement of dielectric constant and strength.

Further, the low temperature fired porcelain of the present invention is not limited to the above-mentioned method of using glass, but the oxide of each component described above,
A method of mixing raw materials such as carbonates and nitrates, molding and firing, a method using a sol-gel method, a hydrothermal synthesis method, and the like are also applicable, but in this case as well, firing at 1050 ° C or lower Therefore, it is desirable to add quartz powder to the molded body in order to contain the quartz crystal in the porcelain.

The low temperature fired porcelain of the present invention thus produced has a coefficient of thermal expansion of 9 to 1 at 40 to 400 ° C.
Since it is 8 × 10 ⁻⁶ / ° C., when used as an insulating substrate for a wiring board or a package, it suppresses the generation of thermal stress due to the difference in thermal expansion when mounted on an external circuit board such as a PC board. be able to. Further, as a matter of course, even in an operating temperature environment, a good mounting state can be maintained without causing defects such as cracks and peeling in the mounting portion due to thermal stress.

Further, the strength is as high as 160 MPa or more,
Since the fracture toughness is as high as 1.4 GPa or more, the mechanical reliability is high, and since the dielectric constant is low and the dielectric loss is small, the signal transmitted in the wiring layer, especially the high frequency signal can be favorably transmitted. Since the relative density of the porcelain is as high as 90% or more, the insulating substrate has excellent chemical resistance, water resistance, thermal conductivity, and insulating characteristics.

(Mounting Structure) Next, the mounting structure of the wiring board of the present invention using the low temperature fired porcelain as an insulating substrate and the package for storing a semiconductor element using the wiring board will be specifically described with reference to the accompanying drawings. To do.

1 and 2 are views showing an example of a mounting structure of a package for housing a semiconductor device which is a preferred example of the wiring board of the present invention, and FIGS. 1 and 2 are ball grid array (BGA) type packages. For example: This semiconductor element housing package has a so-called wiring board as a basic structure in which a metallized wiring layer is provided on the surface or inside of an insulating substrate.

In FIG. 1, A is a package for housing a semiconductor element, and B is an external circuit board. The semiconductor device housing package A of FIG. 1 is composed of an insulating substrate 1, a lid body 2, a metallized wiring layer 3, connection terminals 4 and a semiconductor device 5 housed inside the package.
Constitutes a cavity 6 for hermetically housing the semiconductor element 5 therein.

According to the present invention, the metallized wiring layer 3 is preferably composed mainly of copper or silver, which is a low resistance conductor, and the metallized paste containing the metallized powder applied and fired is sintered. However, according to the present invention, it is preferable that the metal powder is sintered. Further, it is desirable to form at least one plating layer selected from the group consisting of Ni, Cu and Au on the surface of the metallized wiring layer 3 existing on the surface of the insulating substrate 1.

The semiconductor element 5 is adhered and fixed to the central portion of the upper surface of the insulating substrate 1 in the cavity 6 via an adhesive. Further, a plurality of metallized wiring layers 3 are formed on the insulating substrate 1 from the periphery of the semiconductor element 5 to the lower surface thereof, and further, on the lower surface of the insulating substrate 1, as shown in FIG. It is provided and the connection terminal 4 is electrically connected to the metallized wiring layer 3. The connection terminal 4 has a structure in which a protruding terminal 8 made of a brazing material such as solder (tin-lead alloy) is attached to the electrode pad 7.

On the other hand, the external circuit board B has Cu, A as wiring conductors on the surface of an insulator 9 made of a composite material of glass-epoxy resin made of a material containing an organic resin.
This is a general printed circuit board on which a wiring conductor 10 made of a metal such as u, Al, Ni or Pb-Sn is adhered.

According to the present invention, the insulating substrate 1 has 40 to 40
The thermal expansion coefficient at 0 ° C. is 9 to 18 × 10 ⁻⁶ / ° C. or more, and the low temperature fired porcelain prevents the generation of thermal stress due to the difference in thermal expansion when mounted on an external circuit board such as a PC board. In addition to being able to suppress, it is possible to make the porcelain denser, and it is possible to reduce the decrease in strength and maintain high strength even after a thermal cycle due to heat generation during mounting or during operation of the element. According to the present invention, it is possible to reduce the mounting size (length × width) of the semiconductor element 5 and prevent the occurrence of cracks or peeling due to the difference in thermal expansion between the semiconductor element 5 and the insulating substrate 1. it can.

Further, according to the present invention, the amount of warpage on the burnt surface of the surface of the insulating substrate on which the metallized wiring layer is formed is 0.
It can be reduced to 4% or less, particularly 0.2% or less, and the yield of mounting with a semiconductor element, an external circuit board, or the like can be improved. Here, the warp amount is a cross-sectional observation of a surface state on a surface of an insulating substrate on which a metallized wiring layer is formed on two diagonal lines including a center by a surface roughness meter or a scanning electron microscope (SEM). From the obtained chart or SEM photograph, the distance between a straight line connecting the positions of the ends and a straight line parallel to the straight line and passing through the center is measured as the warp amount (t), It is a value obtained by calculating (t / L) × 100 (%), which is the ratio to the length (L) between copies. When the wiring layers are formed on both sides of the wiring board, the warpage rate of both sides may be calculated and the average value thereof may be taken. Further, in the calculation of the warpage rate in the present invention, if the thickness of the wiring layer formed on the surface is 10% or less with respect to the warpage amount, which is sufficiently small, the thickness may be ignored, and the thickness of the wiring layer is determined as the warpage amount. On the other hand, when it exceeds 10%, the thickness of the wiring layer is subtracted from the calculation.

The metallized wiring layer 3 has a frequency of 1 GHz.
Even when transmitting the above high-frequency signal, it is possible to manufacture a wiring board that can favorably transmit the signal. Further, when the chemical resistance of the porcelain is enhanced and a plating film is formed on the metallized wiring layer 3 existing on the surface, the insulating substrate 1 is not eroded by the plating process.

(Mounting Method) To mount the semiconductor element housing package A on the external circuit board B, the protruding terminals 8 made of solder attached to the electrode pads 7 on the lower surface of the insulating substrate 1 of the package A are externally mounted. By placing and abutting on the wiring conductor 10 of the circuit board B, and then heating at a temperature of about 250 to 400 ° C., the protruding terminal 8 itself made of a brazing material such as solder melts, and the wiring conductor 10 It is mounted on the external circuit board B by being bonded to. At this time, it is desirable that a brazing material is adhered to the surface of the wiring conductor 10 in order to easily connect the connection terminal 4 with the brazing material.

As another example, as shown in FIG. 2, it is possible to apply, as the connection terminal 4, a spherical terminal 11 made of a high melting point material to the electrode pad 7 by brazing with a low melting point brazing material 12. This high melting point material needs to have a higher melting point than the low melting point brazing material 12 used for brazing, and the low melting point brazing material 12 for brazing is, for example, Pb40.
When the low-melting point solder of 60% by weight-Sn 60% by weight is used, the spherical terminal 11 has, for example, 90% by weight of Pb-10% by weight of Sn.
High melting point solder, Cu, Ag, Ni, Al, Au, P
It is composed of a metal such as t or Fe.

In such a structure, the spherical terminal 1 attached to the electrode pad 7 on the lower surface of the insulating substrate 1 of the package A
1 is placed and abutted on the wiring conductor 10 of the external circuit board B, and then the spherical terminal 11 is attached to the wiring conductor 10 with the low melting point brazing material 13 such as solder and mounted on the external circuit board B. You can Further, as the low melting point brazing material 13, Au-
The connection terminal 4 may be connected to the external circuit board B using Sn alloy, and a columnar terminal may be used instead of the spherical terminal 11.

[0054]

[Example] (Example 1) The average particle diameter of the ratio shown in Table 1 is 5μ.
m quartz powder, glass powder or SiO ₂
(Amorphous silica) powder, BaCO ₃ powder, B ₂ O ₃
Powder, Al ₂ O ₃ powder, CaO powder, MgO powder, RE ₂
O ₃ powder and ZrO ₂ powder were mixed so as to have the composition shown in Table 1, an organic binder was added, and the mixture was thoroughly mixed. Then, the obtained mixture was uniaxially pressed to give 3.5
It was molded into a molded body having a shape of × 15 mm. Then, this molded body is subjected to a binder removal treatment in an N ₂ + H ₂ O atmosphere at 700 ° C., and is heated at 100 ° C./hr in a nitrogen atmosphere to obtain 950
Calcination was performed for 1 hour. Regarding the rare earth element (RE), Sample No. Yb was used for 1 and 2 and sample N
o. Y was used for 3 to 6.

(Characteristic evaluation) The porosity of the obtained porcelain was measured by the Archimedes method, and the detected crystal was identified by the X-ray diffraction measurement of this porcelain. The content ratio of each crystal and the amorphous phase was calculated from the diffraction peak by the Rietveld method, and the ratio of the crystal phase (a) was calculated from the total content a of the crystals a% by weight and the content b of the amorphous phase b% by weight. / (A + b)) x 100 (%)
Was calculated.

Further, with respect to the obtained sintered body, JISR
Based on 1601, the 4-point bending strength M ₁ was measured. Also,
The thermal expansion coefficient was measured at 40 to 400 ° C., and the dielectric constant and the dielectric loss at 3 GHz were further measured by the cavity resonator method.

(Chemical resistance) The surface area of the porcelain was 5 cm ²
It was cut out so that the weight loss before and after immersion for 100 seconds in a hydrofluoric acid solution of NH ₄ F.HF 5 g / 1 liter of water was measured, and evaluated as chemical resistance.

(Measurement of Warp Amount of Insulating Substrate and Thermal Cycle Characteristic (TCT) During Mounting) Further, using the composition of Table 1, a green sheet having a thickness of 500 μm was prepared by a doctor blade method, and a 25 mm × 25 mm square was prepared. Cut into shape. A Cu metallizing paste was applied to the surface of the sheet by a screen printing method so as to have a thickness of 10 μm.
In addition, through holes were formed at predetermined locations on the green sheet, and Cu metallizing paste was also filled in the through holes. Then, six green sheets coated with the metallizing paste were laminated between the through holes and pressure-bonded. After subjecting this laminate to a binder removal treatment in an N ₂ + H ₂ O atmosphere at 700 ° C., the metallized wiring layer and the insulating substrate were simultaneously fired in a nitrogen atmosphere under the above firing conditions to produce a wiring board.

The surface condition of the obtained wiring board on the surface of the insulating substrate on which the metallized wiring layer was formed was measured with a surface roughness meter on a diagonal line including two vertices. From such a chart, the distance between a straight line connecting the positions of the end portions (e ₁ , e ₂ ) and a straight line parallel to the straight line and passing through the central portion (m) is measured as the warp amount (t), The ratio (t /) to the length (L) between the ends (e ₁ , e ₂ ).
L) × 100 (%) was calculated, and the average value of the warpage rates of the two diagonal lines was calculated as the warpage rate of the wiring board.

Next, as shown in FIG. 1, spherical solder balls (spherical terminals) composed of 90% by weight of Pb and 10% by weight of Sn are attached to the electrode pads provided on the lower surface of the wiring board, and low melting point solder (brazing material) (Pb37%). -Sn 63%). The connection terminals were formed on the entire lower surface of the wiring board at a density of 30 terminals per cm ² .

This wiring board was made of a glass-epoxy board and had a coefficient of thermal expansion of 1 at 40 to 400 ° C.
It was mounted on the surface of a printed circuit board in which a wiring conductor made of copper foil was formed on the surface of an insulator of 3 × 10 ⁻⁶ / ° C. The mounting was performed by aligning the wiring conductor on the printed board and the spherical terminal of the wiring board and connecting and mounting with a low melting point brazing material. Then, the electrical connection state of the mounting portion was measured, and the defective rate (%) in the initial stage of mounting was calculated.

Next, the test sample was mounted on the surface of the printed wiring board for packaging as described above, and the test sample was placed in a constant temperature bath controlled at temperatures of -40 ° C. and 125 ° C. in the atmosphere for 15 minutes / Holding for 15 minutes was set as one cycle, and the cycle was repeated up to 1000 cycles. Then, the electric resistance between the wiring conductor of the printed board and the package wiring board was measured for each cycle, and the number of cycles until a change in the electric resistance appeared was measured up to 1000 cycles. The results are shown in Table 1.

[0063] (Comparative Example) Average particle diameter 5μm amorphous silica powder 50 wt% of, BaCO ₃ powder 40% by weight calculated as BaO and, B ₂ O ₃ powder 4.5 wt%, Al ₂ O ₃ powder 5.4 wt %, CaO powder 0.1% by weight was added and mixed to prepare a molded body in the same manner as in the example, and the molded body was debindered in a N ₂ + H ₂ O atmosphere at 700 ° C. to remove nitrogen. In the atmosphere, the temperature is raised at 100 ° C / hr to 950 ° C.
It was baked for 1 hour. The characteristics were evaluated in the same manner as in Example 1 and shown in Table 1 (Sample No. 10).

[0064]

[Table 1]

From the results shown in Table 1, SiO₂40% by weight
Less, BaO content more than 50% by weight, and
Sample No. containing less than 30 wt% In 1
It has a low coefficient of thermal expansion,
Resistance increased. Also, if the amount of BaO is less than 20% by weight.
A, Al₂O₃Sample No. whose amount is more than 8% by weight 7, B ₂
O₃Less than 1% by weight, RE₂O₃The amount is 5% by weight
More sample No. In 8, the open porosity of the porcelain is less than 2%
It could not be densified and had low strength.

Further, when the amount of B ₂ O ₃ is more than 5% by weight, R
Sample No. ₃ containing no E ₂ O ₃ and containing less than 1% by weight of Al ₂ O ₃ . In No. 9, the strength decreased and the amount of warpage of the insulating substrate increased. In addition, in the case of the sample No. 3 in which the quartz was not added and the quartz was not deposited in the porcelain In No. 10, the thermal expansion coefficient was low, and disconnection was observed after 50 cycles in the thermal cycle test.

On the other hand, according to the present invention, Si is replaced by Si
40 to 70% by weight in terms of O ₂ and Ba as 1 in terms of BaO
And 5 to 40 wt%, and 1 to 5 wt% of B in terms _of B ₂ O _3,
1 to 8% by weight of Al in terms of Al ₂ O ₃ and R of rare earth element
It is contained in a proportion of more than 0% by weight and 5% by weight or less in terms of E ₂ O ₃ , and 30% by weight of quartz crystal is contained in the composition.
Sample No. contained in the above proportions. 2 to 6 are all open porosity 2% or less, strength 160 MPa or more, thermal expansion coefficient 9
~ 18 × 10 ^-6 / ° C, chemical resistance 30 μg or less, dielectric constant 6.5 or less, dielectric loss at 3 GHz 30 × 10 ^-4 or less,
Crystal phase ratio 80% or more, 800 by heat cycle test
It was an excellent porcelain that could maintain a good connection for more than one cycle, and the yield of electrical connection during mounting was also high because the amount of warpage of the insulating substrate was 0.4% or less.

[0068]

As described above in detail, the low temperature fired porcelain composition of the present invention can be fired at a low temperature of 1050 ° C. or lower.
g, It is possible to form metallized wiring layers using Cu metal, has a high coefficient of thermal expansion, does not warp the insulating substrate even when co-firing with the metallized wiring layers, and has excellent dielectric characteristics in the high frequency band. In addition, since it has excellent chemical resistance, it is particularly suitable as an insulating substrate material for a wiring board on which an electronic device or the like is mounted and which is mounted on an external circuit board such as a printed board. Further, the wiring board using this porcelain as an insulating substrate and its mounting structure have high reliability even in a highly integrated large package, and particularly have good transmission characteristics even when transmitting a high frequency signal.

[Brief description of drawings]

FIG. 1 is a drawing (cross-sectional view) illustrating a mounting structure of a BGA type semiconductor element housing package of the present invention.

FIG. 2 is an enlarged cross-sectional view of main parts of another embodiment of the connection terminal.

FIG. 3 is a diagram for explaining a method of measuring a warp rate of a wiring board.

[Explanation of symbols]

1 Insulating Substrate 2 Lid 3 Metallized Wiring Layer 4 Connection Terminal 5 Semiconductor Element 6 Cavity 7 Electrode Pad 8 Protruding Terminal 9 Insulator 10 Wiring Conductor 11 Spherical Terminal 12, 13 Low Melting Brazing Material A Wiring Board (for semiconductor element storage ( BGA type) Package) B External circuit board

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Nakao 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Corporation Research Institute (72) Kenichi Nagae 1-4 1-4 Yamashita-cho, Kokubun-shi, Kagoshima Kyocera Corporation Research Institute (56) Reference JP-A-10-106880 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 35/00-35/49

Claims (6)

(57) [Claims] 1. Si in the total amount is 40 to 70 in terms of SiO _2.
% By weight, and Ba as BaO in an amount of 15 to 50% by weight, B
Is 1 to 5% by weight in terms of B ₂ O ₃ , Al is 1 to 8% by weight in terms of Al ₂ O ₃ , and rare earth element (RE) is more than 0% by weight and 5% by weight or less in terms of RE ₂ O _3. A low temperature fired porcelain composition, characterized in that it contains 30% by weight or more of quartz crystal in the composition. 2. The low temperature fired porcelain composition according to claim 1, which further contains barium silicate crystals. 3. A ratio (a / (a + b)) × 10 of the content of the crystalline phase (a% by weight) and the content of the amorphous phase (b% by weight).
2. 0 (%) is 80% or more.
Alternatively, the low-temperature fired porcelain composition described in 2. 4. The low temperature fired porcelain composition according to claim 1, which has an open porosity of 2% or less and a thermal expansion coefficient of 9 to 18 × 10 ⁻⁶ / ° C. at 40 to 400 ° C. Low temperature firing porcelain. 5. A wiring board in which a metallized wiring layer is provided on at least the surface of an insulating substrate, wherein the insulating substrate comprises the low temperature fired porcelain according to claim 4, and the metallized wiring layer is formed. The warp rate on the surface of the wiring board is 0.4% or less. 6. The wiring board according to claim 5, wherein the metallized wiring layer is mainly made of copper or silver.