JP2695587B2 - Glass ceramics composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to thick film circuit components, ICs,
And a glass-ceramic composition that can be used for producing a ceramic multilayer substrate suitable for high-density mounting of LSI and the like.

[0002]

2. Description of the Related Art Conventionally, alumina ceramics, which are excellent in strength, thermal conductivity and airtightness, have been mainly used as an insulating material constituting a ceramics multilayer substrate. However, since alumina ceramics have a very high firing temperature of 1500 to 1600 ° C., a high melting point metal material such as Mo or W must be used as the material of the inner layer conductor, and these materials have high conductor resistance. Had the disadvantage that Therefore, A
A ceramic material that can be fired at a low temperature of 1000 ° C. or lower is desired and studied so that a metal having a low melting point such as u, Ag, or Cu can be used as the inner layer conductor.

Alumina ceramics have a high thermal expansion coefficient of 70 × 10 ⁻⁷ / ° C., and therefore have a thermal expansion coefficient of 35 × 10 ^-7 / ° C.
^There is also a problem that a silicon chip at ^-7 / ° C cannot be directly mounted.

Further, alumina ceramic has a problem that it is not suitable as a substrate for a high-speed signal circuit because its dielectric constant (ε) is as high as about 10. That is, it is generally known that the speed of a signal propagating in a conductor is delayed as the dielectric constant of the material forming the surroundings is higher. Can't respond to requests.

Under the above circumstances, in recent years, 10
As a material for a low temperature firing substrate that can be fired at a low temperature of 00 ° C. or less, a material in which glass powder and ceramic powder are mixed has been proposed. For example, JP-A-64-
No. 45743, No. 64-51346, JP-A-1-17.
No. 9741, No. 1-252548 and the like are composed of glass powder, ceramic powder, oxidizer, niobium oxide, etc., and the glass powder contains SiO ₂ , Al ₂ O ₃ , oxide of alkaline earth metal, etc. A glass-ceramic composition is disclosed which is contained in the following ratio. These glass-ceramic compositions are proposed for the purpose of increasing mechanical strength and thermal conductivity, improving insulation resistance and dielectric breakdown voltage, and improving solder wettability of conductors. However, it does not have a low coefficient of thermal expansion such that a silicon chip can be directly mounted on it, and does not have a low dielectric constant that can be used for a substrate for high-speed signal circuits.

In Japanese Patent Application Laid-Open No. 1-132194, 1
A glass-ceramic composition having a low dielectric constant and a high strength, which can be sintered at a low temperature of 000 ° C. or lower, has been proposed. The dielectric constant of the glass ceramic composition sintered body was in the range of 7.3 to 7.8, which was still insufficient. Also in terms of low coefficient of thermal expansion, the coefficient of thermal expansion of the glass ceramic composition sintered body in the specification is 60 ×.
The range of 10 ⁻⁷ / ° C. to 72 × 10 ⁻⁷ / ° C. is considered to be appropriate, which is not suitable for directly mounting a silicon chip.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a glass-ceramic composition which can be fired at a low temperature of 1000 ° C. or less, and has a thermal expansion coefficient which is the same as that of a silicon chip. Provided is a glass-ceramic composition capable of producing a ceramic multi-layer substrate having a low dielectric constant of 7 or less, which is similar, and can sufficiently cope with high-speed arithmetic processing, and has high bending strength. To do.

[0008]

The glass-ceramic composition of the present invention comprises, by weight percentage, 40 to 80 glass powders.
%, Ceramic powder 20 to 60%, and the glass powder is SiO ₂ 20 to 50%, Al ₂ O ₃ 10 to 40%.
%, SrO11~25%, MgO6~20%, B 2 O 3
It is characterized by having a composition of 0.1 to 30% and ZnO of 0.1 to 30%.

Examples of the ceramic powder used in the present invention include alumina, mullite, cordierite,
1 selected from the group consisting of zirconia and zirconium silicate
More than one species can be used. In addition, in order to manufacture a multilayer substrate using the glass-ceramic composition of the present invention, for example, it can be manufactured according to the following method.

Glass powder and ceramic powder are weighed at a predetermined mixing ratio and mixed with a binder, a plasticizer, a solvent and the like to prepare a slurry. As the binder, for example, polyvinyl butyral resin, methacrylic acid resin and the like can be used. As the plasticizer, for example, dibutyl phthalate can be used, and as the solvent, for example, toluene, methyl ethyl ketone, or the like can be used.

The slurry thus obtained is applied on a polyester film by a doctor blade method to produce a green sheet having a thickness of about 0.2 mm.
After drying and cutting to a predetermined size, through holes are formed in each green sheet by mechanical processing, and a low-resistance metal material to be a conductor is printed and formed on the through holes and the surface of the green sheet. A plurality of these green sheets are laminated and integrated by thermocompression bonding.

The laminated green sheet thus obtained is heated at a rate of 3 ° C./min and kept at a temperature of 500 ° C. for 30 minutes to remove organic substances in the green sheet. Then, the temperature is raised to 800 to 1000 ° C. at a rate of 10 ° C./min, and the temperature is maintained for 10 minutes to 1 hour to be sintered to obtain a multilayer substrate.

[0013]

The glass ceramic composition of the present invention is characterized by containing SrO and MgO in a predetermined ratio in the glass powder composition. Due to the inclusion of such SrO and MgO, the strontium from the glass phase during firing is It is possible to deposit feldspar and cordierite at the same time, realize a low thermal expansion coefficient that can directly mount a silicon chip, and a low dielectric constant that can sufficiently support high-speed arithmetic processing, and make a ceramic multilayer substrate with high bending strength. be able to.

Hereinafter, the reason for limiting the numerical values of the present invention will be described. The glass-ceramic composition of the present invention comprises 40 to
It consists of 80% glass powder and 20-60% ceramic powder. If the content of the glass powder is less than 40%, that is, if the content of the ceramic powder exceeds 60%, the sintered body will not be densified and the substrate strength will be significantly reduced. If the content of the glass powder exceeds 80%, that is, if the content of the ceramic powder is less than 20%, the glass component rises from the substrate surface after crystallization, and the adhesive strength with the conductor printed on the surface decreases.

In addition, the glass ceramic composition of the present invention
In the glass powder composition, SiO _TwoIs 20-50%,
Preferably, the content is 25 to 45%. SiO_TwoIs glass
Network former, which is a feature of the present invention.
Strontium feldspar and cordiera that precipitate during firing
It is a crystalline constituent of Ito. Therefore, SiO_TwoIs 20%
When it is less than 1, the amount of crystals is small, and the coefficient of thermal expansion is low and low.
Dielectric constant and sufficient mechanical strength cannot be obtained. Ma
If it exceeds 50%, the meltability deteriorates and the softening point
Becomes low and low temperature firing becomes difficult.

Al ₂ O ₃ is 10 to 40%, preferably 1 to 40%.
The content is 5 to 35%, more preferably 20 to 35%.
Al ₂ O _{3 is} also a crystal constituent of strontium feldspar and cordierite. If its content is less than 10%, the amount of crystals will decrease, and if it exceeds 40%, the meltability will deteriorate.

SrO is contained in an amount of 11 to 25%, preferably 11 to 20%. In the present invention, SrO
Is contained as an essential component in the glass powder because it is necessary to precipitate strontium feldspar during firing. If the SrO content is less than 11%, strontium feldspar does not precipitate and the strength becomes low. Also 2
If it exceeds 5%, the thermal expansion coefficient becomes too large.

Like SrO, MgO is an essential component in the glass powder, and is contained in 6 to 20%, preferably 6 to 15%. In the present invention, the inclusion of MgO allows cordierite to be deposited during firing, exhibiting a thermal expansion coefficient close to that of the silicon chip and lowering the dielectric constant. If the content of MgO is less than 6%, cordierite does not sufficiently precipitate, and a low coefficient of thermal expansion and a low dielectric constant cannot be achieved. Also MgO
If the content of the above exceeds 20%, devitrification is likely to occur.

B_TwoO_ThreeAnd ZnO increase the melting property of glass.
Included in the glass powder to improve. B_TwoO_Threeof
The content is 0.1 to 30%, preferably 1 to 25%
It is. The content of ZnO is 0.1 to 30%, preferably
Or 1 to 25%. B _TwoO_ThreeContains more than 30%
If it is rare, the water resistance of the glass deteriorates. In addition, ZnO
If the content is more than 30%, garnite may be used as a foreign crystal.
Precipitates and the thermal expansion coefficient increases. On the other hand, B_TwoO_Threeas well as
As described above, ZnO is a component that improves the meltability of glass.
Minutes, so that each content is less than 0.1%
In some cases, the effect is not sufficiently exhibited.

In the present invention, as described above, SrO
, And MgO are essential components in the glass powder, and by including these oxides, strontium feldspar and cordierite are precipitated from the glass phase during firing, which makes them have a low coefficient of thermal expansion close to that of silicon and is sufficient for high-speed arithmetic processing. A ceramic multilayer substrate having a low dielectric constant which can be dealt with and a high bending strength can be obtained.

[0021]

EXAMPLES The raw materials of silicon dioxide, aluminum oxide, magnesium oxide, strontium carbonate, boric acid, and zinc oxide were prepared so that the glass composition shown in Table 1 was obtained, and these were put in a platinum crucible and heated at 1500 ° C. It was held for 2 hours to melt. Next, the molten glass was quenched and formed into a thin plate, and then pulverized with an alumina ball and classified to obtain a glass powder having an average particle size of about 2 μm.

Each of the glass powders thus obtained is
Various ceramic powders shown in Table 1 were mixed at a predetermined ratio, and a round bar-shaped test body having a diameter of 5 mm and a length of 50 mm, a diameter of 4
0 mm, 2 mm thick disc-shaped test body, and 15 mm wide,
After being press-molded into a strip-shaped test body having a length of 50 mm and a thickness of 1 mm, it was baked at 900 ° C. for 10 minutes.

The coefficient of thermal expansion is measured with a dilatometer using a round bar-shaped specimen, the dielectric constant is measured using a disk-shaped specimen, and the bending strength is measured using a strip-shaped specimen (three-point load method).
Was measured. Table 1 shows the results.

[0024]

[Table 1]

For comparison, as shown in Table 2, a glass powder having a composition outside the range of the present invention was used and mixed with a ceramic powder in the same manner as in the above-mentioned example to prepare a similar test body, which was subjected to thermal expansion. The coefficient, dielectric constant and bending strength were measured. Table 2 shows the results.

[0026]

[Table 2]

As is clear from Table 1, the ceramic substrate formed from the glass-ceramic composition having the composition according to the present invention has a coefficient of thermal expansion of silicon chip of 35 × 10 ^-7 /
It has a low coefficient of thermal expansion close to 0 ° C. and a low dielectric constant of 7 or less. It also has high bending strength and high bending strength.

On the other hand, Comparative Example 1 uses glass powder having a MgO content lower than the range of the present invention, and has a high coefficient of thermal expansion and a high dielectric constant. Comparative Example 2
Has a SrO content lower than the range of the present invention and has a significantly low bending strength.

In Comparative Example 3, a glass powder containing no B ₂ O ₃ and ZnO was used, and a densified sintered body could not be obtained. Comparative Example 4 uses glass powder having a content of Al ₂ O ₃ lower than the range of the present invention,
The coefficient of thermal expansion and the dielectric constant were high, and the bending strength was remarkably reduced.

In Comparative Example 5, glass powder not containing MgO, which is an essential component of the present invention, was used, and 60% of cordierite was contained as a filler. When a large amount of cordierite is contained as a filler, a sintered body having a low thermal expansion coefficient and a low dielectric constant can be obtained,
The bending strength is remarkably inferior as compared with Example 3 in which these properties are almost the same. In the present invention, by including MgO as an essential component, cordierite is precipitated from the glass phase during firing, the deposited cordierite achieves a low thermal expansion coefficient and a low dielectric constant, and the deposited cordierite is fine. This is because the crystal grains contribute to the improvement of bending strength.

Next, a ceramic multilayer substrate was prepared using the glass-ceramic compositions of Examples 9-11. FIG. 1 is a cross-sectional view of a ceramic multilayer substrate after firing. 1 is a via conductor, 2 is an inner layer conductor pattern, 3 is an outermost layer conductor, 4 is a bare IC chip, 5 is a protruding electrode, and 6 is a joint. It is a material. Table 3 shows the warpage and deformation of the manufactured ceramic multilayer substrate, the terminal strength, and the amount of change in the connection resistance value.

[0032]

[Table 3]

First, glasses having the compositions of Examples 9 to 11
Green using a ceramic composition and known technology
A plurality of sheets were produced. Furthermore, each obtained green leaf
A via hole is provided at a predetermined position of the
To form via conductors 1, and in CuO by a printing method.
The inner conductor pattern 2 was formed using the layer conductor. That
Later, these green sheets are laminated to form a multilayer,
After indah, H_Two/ N _TwoReduced by green gas,
It was baked in a nitrogen atmosphere at 900 ° C. for 10 minutes. like this
Multilayer substrate co-fired with inner layer conductor
No warpage or deformation was observed in the.

A Cu conductor was printed on the ceramic multilayer substrate and baked to form the outermost layer conductor 3, and its terminal strength was measured. The terminal strength is 0.9 kg for a 1.5 mm square electrode
The above values are at a practical level, but in this example, as shown in Table 3, a value of 0.9 to 1.8 kg / 1.5 mm square was shown, and it was found that it could be sufficiently practically used.

Further, a 6 mm square bare IC chip 4 was soldered to the ceramic multilayer substrate by a flip chip mounting method using eutectic solder as a bonding material. Heat cycle -40 to +125 for the multilayer board after chip mounting
When the test was conducted at 100 ° C. for 100 cycles, there was no disconnection at the connection part and one bump (the size of the IC pad was 100 μm).
The amount of change in resistance per hit was ± 20 mΩ, which was a good value. With such a composition having a coefficient of thermal expansion close to that of a silicon chip, a multilayer board with excellent reliability and flip-chip mounting could be obtained.

[0036]

As described above, by using the glass-ceramic composition according to the present invention as a ceramic material for a ceramic multilayer substrate, it is possible to perform firing at a temperature of 1000 ° C. or lower, and to have a low thermal expansion for directly mounting a silicon chip. It is possible to produce a ceramic multilayer substrate having a coefficient, a low dielectric constant of 7 or less that can sufficiently cope with high-speed arithmetic processing, and high bending strength.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which an IC chip is mounted by producing a ceramic multilayer substrate using the glass ceramic composition of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Via conductor 2 ... Inner layer conductor pattern 3 ... Outermost layer conductor 4 ... Bare IC chip 5 ... Projection electrode 6 ... Bonding material

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C04B 35/18 C04B 35/16 A 35/195 35/18 Z 35/48 35/48 Z (72) Inventor Shigetoshi Segawa 2-10-10 Kotobuki-cho, Kagawa Prefecture Matsushita Kotobushiki Kogyo Co., Ltd. (72) Inventor Yasukazu Fukunaga 2-20-10 Kotobukicho Takamatsu-shi Kotobuki Matsushita Kotobushiki Kogyo Co., Ltd. (72 ) Inventor Yoshio Mayahara, 2-7-1, Hararashi, Otsu, Shiga Prefecture, Nippon Electric Glass Co., Ltd. (72) Inventor, Hiromitsu Watanabe, 2-7 Hararashi, Otsu City, Shiga, Japan (72) Invention Kazuyoshi Shindo 2-7-1, Harashiran, Otsu City, Shiga Nippon Electric Glass Co., Ltd. (56) Reference JP-A-63-107838 (JP, A) JP-A-2-30641 (JP, A)

Claims (2)

(57) [Claims] 1. Glass powder 40-80 by weight percentage.
%, Ceramic powder 20 to 60%, and the glass powder is SiO ₂ 20 to 50%, Al ₂ O ₃ 10 to 40%.
%, SrO11~25%, MgO6~20%, B 2 O 3
A glass ceramic composition having a composition of 0.1 to 30% and ZnO of 0.1 to 30%. 2. The ceramic powder is one or more selected from the group consisting of alumina, mullite, cordierite, zirconia and zirconium silicate.
The glass-ceramic composition according to claim 1.