JP2892163B2 - Low temperature firing glass ceramic body - 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 glass ceramic body which can be used as an insulating substrate such as a multilayer wiring board on which a semiconductor integrated circuit element is mounted.

[0002]

2. Description of the Related Art Conventionally, an insulating substrate such as a multilayer wiring board on which a semiconductor element, particularly a semiconductor integrated circuit element made of silicon, is mounted is generally made of alumina ceramics having excellent electric insulation and heat resistance and high strength. And an electric wiring circuit was formed by printing a thick metalized metal layer made of a high melting point metal such as molybdenum (Mo) and tungsten (W) on a substrate made of the alumina ceramic or the like. A multilayer ceramic wiring board has been obtained by multilayering and firing integrally.

In recent years, however, the size of semiconductor devices and the speed of signal propagation have rapidly increased, and when the semiconductor devices are mounted on the above-mentioned conventional multilayer ceramic wiring board, the alumina constituting the semiconductor integrated circuit device has become increasingly difficult. While the coefficient of thermal expansion of ceramics is 6.0 to 7.5 × 10 ⁻⁶ / ° C., the coefficient of thermal expansion of silicon is 3.5 × 10 ⁻⁶ / ° C.
Since the temperature greatly differs from the temperature of about ° C., a large thermal stress is generated when the semiconductor integrated circuit device is mounted, and the semiconductor integrated circuit device is damaged by the thermal stress or peeled off from the insulating base. Was.

The dielectric constant of the alumina ceramic constituting the insulating substrate is 9 to 10 (room temperature, 1 MHz).
Since the delay time of high-frequency propagation is proportional to the square root of the dielectric constant, the propagation speed of the signal transmitted through the metallized metal layer provided on the insulating base is slow, and the insulation with a lower dielectric constant is required for high-speed signal propagation. A substrate was required.

[0005] Further, since the insulating substrate made of the alumina ceramic has a high firing temperature of about 1600 ° C,
The metallized metal layer forming the electric wiring circuit is also limited to high melting point metals such as molybdenum and tungsten, and the wiring resistance of the electric wiring circuit increases from the high electric resistivity and high density wiring, the voltage drop increases, Therefore, it has been required that a metal such as gold or copper having a low resistivity can be used as a material for an electric wiring circuit.

In order to solve the above problems, Japanese Patent Application Laid-Open No. 63-248199 discloses that the insulating base of a multilayer wiring board is replaced with alumina ceramics and has a coefficient of thermal expansion similar to that of silicon constituting a semiconductor integrated circuit element. Alumina powder is added to borosilicate glass, which has a low coefficient of thermal expansion and a low dielectric constant of 4.6 or less, and has a high softening point and a low softening point glass capable of keeping the firing temperature at around 1000 ° C. There has been proposed a glass-ceramic multilayer wiring board made of the above.

[0007]

However, in a glass-ceramic multilayer wiring board obtained by adding alumina powder to the borosilicate glass which is a high silica glass and a low softening point glass, the dielectric constant is low but the flexural strength is 15 kg. / Mm
² or less, even if it is necessary to obtain practical mechanical strength as a board by increasing the thickness of the board, even if the board is used for input / output pins for electrical signals for electrically connecting the board to an external circuit, etc. In the step of brazing, when locally heated, due to thermal stress caused by the difference in thermal expansion between the brazing material and the substrate material, cracks and peeling of the metallized metal layer on the substrate surface are caused on the substrate. This has caused a problem that a high-quality multilayer wiring board having excellent reliability cannot be obtained.

Further, if a trace amount of carbon remains on the substrate, the substrate becomes porous, the color tone becomes uneven, and the mechanical and electrical characteristics of the substrate deteriorate. As can be seen from the graph of the relationship between the temperature and the free energy change in the reaction between water and water vapor, carbon is desorbed at a temperature of 680 ° C. or higher, preferably 750 ° C. or higher, which is the temperature at which carbon reacts with water vapor to form carbon dioxide gas and scatters. Need to be a binder.

However, since glass having a softening point of 1000 ° C. or less is used for the glass ceramic multilayer wiring board, closed pores are formed due to the softening flow of the glass at a low softening point, and the binder is completely removed. And carbon remains at 100 ppm or more.

Conversely, when using a glass that does not soften and flow at a temperature of 750 ° C. or more, the softening point of the glass generally becomes 850 ° C. or more from the above temperature range. Has a problem that the temperature exceeds about 1050 ° C., which is close to the melting point of copper, and cannot be fired simultaneously with the formation of the copper conductor layer.

[0011]

SUMMARY OF THE INVENTION The present invention has been developed in order to solve the above-mentioned drawbacks. The object of the present invention is to provide a metallized metal layer provided on the insulating substrate with a high mechanical strength. In addition to being able to be brazed firmly, the thermal expansion coefficient and dielectric constant of the insulating base are low, copper is used as a conductor material, the residual carbon can be extremely reduced, the binder can be removed, and low-temperature firing at around 1000 ° C. It is an object of the present invention to provide a low-temperature fired glass-ceramic body which can be used as an extremely reliable insulating substrate for a multilayer wiring board which enables the above.

[0012]

According to the present invention, a low-temperature fired glass-ceramic body is prepared by adding a ceramic insulating material to borosilicate glass, and the crystal phase of the glass-ceramic sintered body having a firing temperature of 900 to 1050 ° C. is 18%. 24 wt% of alumina (Al ₂ O _3), 8~17 wt% of silica (Si
O ₂ ) and 13 to 25% by weight cordierite (2Mg)
O.2Al ₂ O ₃ .5SiO ₂ ) with the balance being 77
It is made of borosilicate glass having a softening point in the range of 0 to 850 ° C.

That is, the borosilicate glass has a softening point of 770.
If the temperature is lower than ℃, the softening flow of the glass at the time of debinding is severe, so that the shrinkage of the glass ceramic sintered body is large, and 100 ppm or more of carbon remains in the glass ceramic sintered body, and the strength of the sintered body is deteriorated. And withstand voltage degradation. The borosilicate glass has a softening point of 85.
If the temperature exceeds 0 ° C., a dense sintered body cannot be obtained unless the firing temperature is 1050 ° C. or higher.

When the content of alumina (Al ₂ O ₃ ) is less than 18% by weight,
The flexural strength of the sintered body is reduced to 15 kg / mm ² or less, the acid resistance is deteriorated, and the glass at the interface between the conductor layer and the sintered body is eroded in a process such as plating and remains in the eroded portion. If a small amount of water is heated in a later step, the metallized metal layer may be blistered or the metallized metal layer may be peeled off. If it exceeds 24% by weight, the dielectric constant of the sintered body becomes 5%.
The above is a large value and is out of the practical range.

When the content of quartz (SiO ₂ ) is less than 8% by weight, the sintering temperature becomes 1050 ° C. or more and the dielectric constant becomes as large as 5 or more. On the other hand, if it exceeds 17%, the acid resistance of the sintered body is deteriorated, or the coefficient of thermal expansion is 4.5 × 10
^It is larger than ^-6 / ° C.

Next, cordierite (2MgO.2Al)
It is less than the content of ₂ O ₃ · 5SiO ₂₎ is 13 wt%,
When the coefficient of thermal expansion of the sintered body exceeds 4.5 × 10 ⁻⁶ / ° C., and when it exceeds 25% by weight, the coefficient of thermal expansion of the sintered body becomes 3.
It becomes lower than 5 × 10 ⁻⁶ / ° C., which is too low than the coefficient of thermal expansion of silicon constituting the semiconductor integrated circuit element, and both are not practical.

If the sintering temperature is lower than 900 ° C.,
Gold (Au), silver (Ag), copper (Cu) with low resistivity
When the temperature exceeds 1050 ° C., the metal having a low resistance is melted and an electric wiring circuit cannot be formed. Therefore, the softening point of the borosilicate glass, the content of the crystal layer of the glass ceramic sintered body, and the firing temperature are specified in the above ranges.

From the viewpoint of the firing temperature, the coefficient of thermal expansion, the dielectric constant and the acid resistance, the low-temperature fired glass-ceramic body is composed of 19 to 21% by weight of alumina (Al ₂ O ₃ ), 11
15wt% of silica (SiO _2), 18~23 wt% cordierite _{(2MgO · 2Al 2 O 3 ·} 5Si
More preferably, the crystal layer of O ₂ ) and the remainder comprise borosilicate glass having a softening point in the range of 780-820 ° C.

[0019]

A low-temperature fired glass-ceramic body obtained by adding a ceramic insulating material to borosilicate glass contains, as a main component, borosilicate glass having a low strength but a small dielectric constant, and the borosilicate glass has a dielectric constant and a thermal expansion coefficient. And a crystal layer of alumina having a high dielectric strength, a crystal layer of quartz having a low dielectric constant, and a crystal layer of cordierite having a low thermal expansion coefficient and a low dielectric constant. In addition, the coefficient of thermal expansion is low, and the strength can be adjusted high.

In addition, by using borosilicate glass having a softening point of 770 to 850 ° C., it is possible to reduce the residual carbon to 100 ppm or less by debinding in a non-oxidizing atmosphere and to use copper having a low electric resistance as a conductive material. Becomes

[0021]

Next, the low-temperature fired glass ceramic body of the present invention will be described in detail with reference to examples. SiO ₂ of 72 to 76% composition of the raw material powder is by weight, 15-17% of B ₂ O
₃ , 2-4% Al ₂ O ₃ , 1.5% or less MgO,
ZrO ₂ , Na ₂ O, K ₂ O and Li of 1.1 to 1.4
Alumina (Al ₂ O ₃ ), quartz (SiO ₂ ), and cordierite (2MgO.2Al ₂ O ₃ .5Si) are added to a borosilicate glass powder having a total amount of ₂ O of 2.0 to 3.0%.
The composition of the glass ceramic sintered body of each powder of O ₂ ) is shown in Table 1.
And wet-mixing the prepared powder with a ball mill using methanol as a solvent, and then adding the paraffin wax to the dried mixed powder, granulating the powder, and reducing the pressure to a molding pressure of about 1000 kg / cm ^2. Each of the disk-shaped and two types of prism-shaped formed bodies was press-formed. Next, after debinding the molded body at a temperature of 350 ° C.,
It was fired at a temperature of 1080 ° C. to obtain disk-shaped and two types of prismatic glass-ceramic sintered bodies, respectively.

First, X-ray diffraction was performed using one kind of the above-mentioned glass ceramic sintered body, and compared with a calibration curve diagram of each crystal layer prepared from the peak ratio of the diffraction pattern of a standard sample of alumina, quartz and cordierite, The content of each crystal layer was confirmed. Next, an evaluation sample having a diameter of 60 mm and a thickness of 2 mm was polished from the disc-shaped glass ceramic sintered body, and a frequency of 1 MHz and an input signal level of 1. were obtained based on the evaluation sample according to JIS-C-2141. The dielectric constant was measured under measurement conditions of 0 Vrms. Similarly, a prismatic glass ceramic sintered body is 6 mm long, 6 mm wide, and 50 m long.
The average coefficient of thermal expansion in the temperature range of 40 to 400 ° C. was measured using the evaluation sample polished to m.

Further, the evaluation sample polished to 3 mm in length, 4 mm in width and 40 mm in length was used in the same manner as in JIS-R
A three-point bending test was performed according to the specification of -1601, and the bending strength was determined. Further, the evaluation sample was immersed in a 10% hydrochloric acid solution at room temperature for 15 minutes, and the weight change before and after immersion was measured to evaluate the acid resistance. On the other hand, to a mixed powder prepared and pulverized so that the composition of the glass ceramic sintered body becomes the value shown in Table 1 in the same manner as described above, a binder containing an acrylic resin as a main component, a dispersant, a plasticizer, and an organic solvent are added. To form a slurry, and the slurry is made to have a thickness of about 0.
A 2 mm green sheet molded body was obtained. Subsequently, a thick wiring of an evaluation wiring pattern is printed on the surface of the green sheet by a screen printing method using a conductive paste containing copper as a main component, and after drying, a plurality of green sheets having the evaluation wiring pattern are heated to 55 ° C. 100 kg / cm ² under temperature
And then thermocompression bonded.

The laminate was debindered in a nitrogen atmosphere containing water vapor at a temperature of 750 to 800 ° C., and then fired in a nitrogen atmosphere at a temperature of 880 to 1100 ° C. The thus obtained sintered body was pulverized in an alumina mortar, and then heat-treated in the air at a temperature of 1200 ° C., and the amount of residual carbon in the sintered body was determined from the amount of carbon dioxide gas generated at this time. The above results are shown in Tables 1 and 2.

Table 1

Table 2

[0027]

As described above, the low-temperature fired glass-ceramic body of the present invention is obtained by adding a ceramic insulating material to borosilicate glass having a softening point of 770 to 850 ° C. and increasing the firing temperature to 900 to 850 ° C.
The crystal layer of the glass ceramic sintered body fired at a low temperature of 1050 ° C. has 18 to 24% by weight of alumina (Al ₂
O ₃ ), 8 to 17% by weight of quartz (SiO ₂ ) and 13 to
25 wt% of cordierite (2MgO · 2Al ₂ O ₃
(5SiO ₂ ) and the remainder made of the above borosilicate glass, it is possible to suppress the residual carbon in the sintered body to a very low level, to provide a semiconductor integrated circuit device having high mechanical strength and a high coefficient of thermal expansion of the insulating base. About the same as the coefficient of thermal expansion of silicon
To provide a low-temperature fired glass-ceramic body suitable as an insulating material for a high-quality multilayer wiring board, for example, in which copper having a very low dielectric constant and a low resistivity can be formed as a conductor layer. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between temperature and free energy change in the reaction between carbon and water vapor for explaining the softening point of the borosilicate glass of the present invention.

[Table 1]

[Table 2]

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 35/00-35/22 C04B 35/622-35/636

Claims (1)

(57) [Claims] 1. A glass-ceramic sintered body obtained by adding a ceramic insulator material to borosilicate glass, wherein the glass-ceramic sintered body having a firing temperature of 900 to 1050 ° C. has a crystal phase of 18 to 24% by weight of alumina. (Al ₂
O ₃ ), 8 to 17% by weight of quartz (SiO ₂ ) and 13 to
25 wt% of cordierite (2MgO · 2Al ₂ O ₃
A low-temperature fired glass-ceramic body containing (5SiO ₂ ), the balance being borosilicate glass having a softening point in the range of 770 to 850 ° C.