JPH0758454A - Glass ceramic multilayered substrate - Google Patents

Abstract

PURPOSE:To realize a glass ceramic multilayer substrate to be manufactured by low temperature baking, to have a thermal expansion coefficient approximating to that of a silicon chip and to indicate a permittivity low enough to cope with a rapid operational processing, by a method wherein the glass component of the ceramic multilayer substrate comprising the glass component and a filler component has a specific composition. CONSTITUTION:The title glass ceramic multilayered substrate is composed of the glass component of 40-80wt.% and the filler components of 20-60wt.% while the glass components in details comprising SiO2; 20-50wt.%, Al2O3; 10-40wt.%, SrO; 11-25wt.%, MgO; 60-20wt.%, B2O3; 0.1-30wt.%, ZnO; 0.1-30wt.%. In such a composition, specific ratios of SrO and MgO are contained in the glass components to enable strotium feldspar and cordierite to be simultaneously deposited from the glass phase in the baking step so that a lower thermal expansion coefficient capable of directly mounting silicon chip as well as a low permittivity not exceeding seven capable of sufficiently coping with the rapid operational processing step may be realized simultaneously enabling the high mechanical strength to be gained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to thick film circuit parts, ICs,
And a glass-ceramic multilayer substrate suitable for high-density mounting of LSI and the like.

[0002]

2. Description of the Related Art Conventionally, alumina ceramics excellent in mechanical strength, thermal conductivity and airtightness have been mainly used as a ceramic multilayer substrate. However, since alumina ceramics has an extremely high firing temperature of 1500 to 1600 ° C., a metal material having a high melting point such as Mo or W must be used as a material for the inner layer conductor, and these materials have high conductor resistance. It had a drawback. Therefore, Au, Ag, Cu
A ceramic material that can be fired at a low temperature of 1000 ° C. or lower has been desired and studied so that a metal having a low melting point such as the above can be used as the inner layer conductor.

Alumina ceramics has a high coefficient of thermal expansion of 70 × 10 ⁻⁷ / ° C., so that the coefficient of thermal expansion is 35 × 10 7.
There was also a problem that a silicon chip with a temperature of ^-7 / ° C could not be mounted directly.

Further, since alumina ceramics has a high dielectric constant (ε) of about 10, there is a problem that it is not suitable as a substrate for high-speed signal circuits. 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 periphery thereof is delayed. I cannot meet the demand.

Under the above circumstances, in recent years, a glass ceramic multilayer substrate has been proposed which is made by mixing glass powder and a filler component and can be manufactured by low temperature firing at 1000 ° C. or lower. For example, JP-A-64-45743, JP-A-64-51346, JP-A-1-179741 and JP-A-1
No. 252548, etc., SiO ₂ , Al ₂ O ₃ , RO
Glass powder containing a predetermined ratio, filler powder, oxidizer,
A glass-ceramic multilayer substrate formed by firing niobium oxide or the like is disclosed. These glass-ceramic multilayer substrates 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.

Further, in JP-A-1-132194, 1
A glass-ceramic wiring board that can be sintered at a low temperature of 000 ° C. or lower, has a low dielectric constant, and has high strength has been proposed. However, although it is intended to obtain a low dielectric constant, its dielectric constant is The range was 7.3 to 7.8, which was still insufficient. Also in terms of low coefficient of thermal expansion, the coefficient of thermal expansion is 60 to 72 × 1 in the description in the specification.
The range of 0 ^-7 / ° C is considered to be appropriate, which is not suitable for directly mounting a silicon chip.

The object of the present invention is to solve the above problems of the prior art, and it can be manufactured by low temperature firing at 1000 ° C. or lower. The coefficient of thermal expansion is close to that of silicon chips, and high speed is achieved. It is an object of the present invention to provide a glass-ceramic multilayer substrate having a low dielectric constant of 7 or less that can sufficiently cope with arithmetic processing and high mechanical strength.

[0008]

The glass-ceramic multilayer substrate of the present invention has a glass component of 40 to 80 in weight percentage.
%, The filler component is 20 to 60%, and the glass component is SiO ₂ 20 to 50%, Al ₂ O ₃ 10 to 40%.
%, SrO 11-25%, MgO 6-20%, B ₂
It is characterized by having a composition of 0.1 to 30% O _{3 and} 0.1 to 30% ZnO.

As the filler component used in the present invention, for example, one or more selected from the group consisting of alumina, mullite, cordierite, zirconia and zirconium silicate can be used.

The glass-ceramic multilayer substrate of the present invention is manufactured by the following method. First, in weight percentage, S
_{iO 2 20~50%, Al 2 O} 3 10~40%, S
rO 11-25%, MgO 6-20%, B ₂ O ₃
Glass powder having a composition of 0.1 to 30% and ZnO of 0.1 to 30%, and alumina, mullite, cordierite,
1 selected from the group of zirconia and zirconium silicate
One or more kinds of filler powders 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, or the like can be used. Further, 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 onto a polyester film by a doctor blade method to produce a green sheet having a thickness of about 0.2 mm.
After this is dried and cut into a predetermined size, a through hole is formed in each green sheet by mechanical processing, and a low resistance metal material to be a conductor is printed and formed on the surface of the through hole and 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 held at a temperature of 500 ° C. for 30 minutes to remove the 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 the glass-ceramic multilayer substrate of the present invention.

[0013]

The glass-ceramic multilayer substrate of the present invention is characterized by containing SrO and MgO in a predetermined ratio in the glass component. Due to the inclusion of such SrO and MgO, the strontium feldspar from the glass phase during firing. And, cordierite can be deposited at the same time, and a low thermal expansion coefficient capable of directly mounting a silicon chip and a low dielectric constant sufficient for high-speed arithmetic processing can be realized, and high mechanical strength can be obtained.

The reason for limiting the numerical values of the present invention will be described below. The glass-ceramic multilayer substrate of the present invention comprises 40
It is composed of -80% glass component and 20-60% filler component. If the proportion of the glass component is less than 40%, that is, if the content of the filler component exceeds 60%, densification does not occur during firing and the mechanical strength remarkably decreases. Further, if the proportion of the glass component exceeds 80%, that is, if the filler component is less than 20%, the glass component is raised from the substrate surface after crystal precipitation, and the adhesive strength with the conductor printed on the surface is lowered.

In the glass-ceramic multilayer substrate of the present invention, SiO ₂ is contained in the glass component in an amount of 20 to 50%, preferably 25 to 45%. SiO ₂ is a glass network former and is also a crystal constituent of strontium feldspar and cordierite. Therefore,
If the SiO ₂ content is less than 20%, the amount of crystals will decrease,
It is not possible to obtain a low coefficient of thermal expansion, a low dielectric constant and sufficient mechanical strength. On the other hand, if it exceeds 50%, the melting property of the glass tends to be poor and the softening point tends to be high, so that low temperature firing becomes difficult.

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

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 component because it is necessary to precipitate strontium feldspar during firing. If the SrO content is less than 11%, strontium feldspar will not precipitate and the mechanical strength will decrease. If it exceeds 25%, the coefficient of thermal expansion becomes too large.

Like SrO, MgO is an essential component in the glass component, 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 a silicon chip and lowering the dielectric constant. When the content of MgO is less than 6%, cordierite is not sufficiently precipitated and a low thermal expansion coefficient and a low dielectric constant cannot be achieved. In addition, the content of MgO is 2
If it exceeds 0%, devitrification tends to occur.

B₂O₃And ZnO improve the meltability of glass.
Included in the glass component to improve. B₂O₃of
Content is 0.1-30%, preferably 1-25%
Is. The content of ZnO is 0.1 to 30%, which is preferable.
It is preferably 1 to 25%. B ₂O₃Is over 30%
If it gets wet, the water resistance of the glass deteriorates. In addition, ZnO
If the content exceeds 30%, garnite as heterogeneous crystals
Are deposited and the coefficient of thermal expansion becomes high. On the other hand, B₂O₃as well as
ZnO is a component that improves the meltability of glass as described above.
Therefore, if the content is less than 0.1%,
In some cases, the effect is not fully exerted.

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. It can have a correspondingly low dielectric constant and have high mechanical strength.

[0021]

[Examples] Raw materials of silicon dioxide, aluminum oxide, magnesium oxide, strontium carbonate, boric acid, and zinc oxide were prepared so that the glass compositions shown in Table 1 were obtained, and these were placed in a platinum crucible at 1500 ° C. Hold for 2 hours to melt. Next, this molten glass was rapidly cooled to form a thin plate, which was then crushed with an alumina ball and classified to obtain a glass powder having an average particle size of about 2 μm.

Each glass powder thus obtained was
A mixture of various filler powders shown in Table 1 at a predetermined ratio, a round bar-shaped test body having a diameter of 5 mm and a length of 50 mm, a diameter of 40 m
After being press-molded into a disc-shaped test body of m, a thickness of 2 mm, and a strip-shaped test body of a width of 15 mm, a length of 50 mm, and a thickness of 1 mm, it was baked at 900 ° C. for 10 minutes.

The thermal expansion coefficient was measured with a dilatometer using a round bar-shaped test body, the dielectric constant was measured using a disk-shaped test body, and the bending strength (three-point load method) was measured using a strip-shaped test body.
Was measured.

The results are shown in Table 1.

[0025]

[Table 1]

For comparison, as shown in Table 2, a glass powder having a composition outside the scope of the present invention was used and mixed with a filler 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. The results are shown in Table 2.

[0027]

[Table 2]

As is apparent from Table 1, each sample of the examples has a low coefficient of thermal expansion close to the thermal expansion coefficient of silicon chip of 35 × 10 ⁻⁷ / ° C., and the dielectric constant is as low as 7 or less. Is shown. Further, it is found that the bending strength is also high and the mechanical strength is high.

On the other hand, in Comparative Example 1, the content of MgO in the glass component is less than the range of the present invention, so that the coefficient of thermal expansion and the dielectric constant are high. In Comparative Example 2, the content of SrO in the glass component was less than the range of the present invention,
Bending strength is extremely low.

In Comparative Example 3, since B ₂ O ₃ and ZnO were not contained in the glass component, a densified sintered body could not be obtained. Comparative Example 4 is Al ₂ O ₃ in the glass component.
Since the content of is less than the range of the present invention, the coefficient of thermal expansion and the dielectric constant are high, and the bending strength is remarkably lowered.

In Comparative Example 5, the glass component does not contain MgO, which is an essential component, and 60% cordierite is contained as a filler component. When a large amount of cordierite is contained as a filler component, a low thermal expansion coefficient and a low dielectric constant are obtained, but the bending strength is significantly inferior to that of Example 3 in which these properties are almost the same. In the present invention, by containing MgO as an essential component in the glass component, cordierite is precipitated from the glass phase during firing, and the deposited cordierite achieves a low thermal expansion coefficient and a low dielectric constant, and This is because the cordierite formed is fine crystal grains and contributes to improvement in bending strength.

Next, using the glass-ceramic compositions of Examples 9 to 11, ceramic multilayer substrates were prepared. FIG. 1 is a cross-sectional view of a glass-ceramic multilayer substrate, in which 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 bonding material. is there. Table 3 shows the presence or absence of warpage or deformation of the produced glass-ceramic multilayer substrate, the terminal strength, and the amount of change in the connection resistance value, respectively.

[0033]

[Table 3]

First, glasses having the compositions of Examples 9 to 11
Green with known technology using ceramics composition
A plurality of sheets were prepared. Further obtained each green
A via hole is provided at a predetermined position in the board to fill the CuO via conductor.
Filled to form the via conductor 1, and also in CuO by printing method
The inner layer conductor pattern 2 was formed using the layer conductor. That
After that, these green sheets are laminated to form a multilayer,
After the inder, H₂/ N ₂Reduced by green gas,
It was baked for 10 minutes in a nitrogen atmosphere at 900 ° C. like this
Glass ceramics that were co-fired with the inner conductor
No warpage or deformation was observed in the layered substrate.

In addition, Cu is added to the glass-ceramic multilayer substrate.
The conductor was printed and fired to form the outermost layer conductor 3, and its terminal strength was measured. If the terminal strength is 0.9 kg or more for a 1.5 mm square electrode, it is at a practical level, but in this embodiment, as shown in Table 3, it is 0.9 to 1.8 kg / 1.5 mm.
The value of the angle was shown, and it was found that it could withstand practical use.

Further, a 6 mm square bare IC chip 4 was soldered to a glass ceramic multilayer substrate by a flip chip mounting method using eutectic solder as a bonding material. Heat cycle -40 to + for multi-layer board after chip mounting
When the test was conducted at 125 ° C. for 100 cycles, there was no disconnection at the connection part and 1 bump (IC pad size was 100
The amount of change in resistance value per μm was ± 20 mΩ, which was a good value. As described above, the composition in which the coefficient of thermal expansion is close to that of the silicon chip makes it possible to obtain the flip-chip-mounted glass-ceramic multilayer substrate with excellent reliability.

[0037]

As described above, the glass-ceramic multilayer substrate of the present invention can be fired at a temperature of 1000 ° C. or less, has a low coefficient of thermal expansion for directly mounting a silicon chip, and is sufficiently compatible with high-speed arithmetic processing. It is possible to manufacture a ceramic multilayer substrate having a low dielectric constant of 7 or less and having high mechanical strength.

[Brief description of drawings]

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

[Explanation 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 (72) Inventor Shigetoshi Segawa 2-2-10 Kotobukicho, Takamatsu-shi, Kagawa Matsushita Electronics Industry Co., Ltd. (72) Inventor Yasushi Fukunaga 2-chome, Kotobuki, Takamatsu-shi, Kagawa No. 10 In Matsushita Electronics Industry Co., Ltd. (72) Inventor Yoshio Mayahara 2-7-1 Harumi Arashi, Otsu City, Shiga Prefecture Nihon Denki Glass Co., Ltd. (72) Inventor Hiromitsu Watanabe 2-7 Harashira, Otsu City, Shiga Prefecture No. 1 in Nippon Electric Glass Co., Ltd. (72) Inventor Kazuyoshi Shindo 2-7-1 Harusan, Otsu City, Shiga Prefecture In Nippon Electric Glass Co., Ltd.

Claims (2)

[Claims] 1. A glass component of 40 to 80 in weight percentage.
%, A filler component 20 to 60%, the glass component SiO ₂ 20 to 50%, Al ₂ O ₃ 10 to 40%,
SrO 11-25%, MgO 6-20%, B ₂ O ₃
A glass-ceramic multilayer substrate having a composition of 0.1 to 30% and ZnO of 0.1 to 30%. 2. The filler component is alumina, mullite,
The glass-ceramic multilayer substrate according to claim 1, which is one or more selected from the group consisting of cordierite, zirconia, and zirconium silicate.