JP2752301B2 - Composition for ceramic substrate and ceramic wiring substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for a ceramic substrate and a ceramic wiring substrate, and more particularly to a composition for a ceramic substrate containing a crystallized glass material and a ceramic wiring substrate comprising this composition.

[0002]

2. Description of the Related Art As a wiring substrate for mounting electronic components such as semiconductor elements, gold and silver are deposited on the inside and surface of an insulating substrate made of a glass ceramic material which can be fired at a low temperature in which alumina powder is dispersed in a borosilicate glass material. It is known that a wiring layer formed of a conductive material of a silver, silver, or copper system is formed. This type of wiring board has a small dielectric constant of about 6 to 7 and a wiring layer made of a low-resistance conductive material, so that the signal propagation speed in the wiring layer is increased.

[0003]

The wiring board using the glass ceramic material has a coefficient of thermal expansion of about -5 × 10 ^-2 % when cooled from 20 ° C. to -196 ° C. The gallium-arsenic semiconductor element is significantly different from the thermal expansion coefficient of −9 / × 10 ⁻² % when it is similarly cooled. Therefore, when the gallium-arsenic semiconductor element is mounted on the conventional wiring board, the gallium-arsenic semiconductor element and the wiring board may be damaged when cooled to an extremely low temperature, or the semiconductor element may be separated from the wiring board. Therefore, it is substantially difficult to mount the gallium-arsenic semiconductor element on the conventional wiring board.

An object of the present invention is to provide a composition for a ceramic substrate, which is capable of forming a ceramic wiring substrate having a low dielectric constant and a high strength and capable of mounting a gallium-arsenide semiconductor element. Another object of the present invention is to reduce the dielectric constant and increase the strength of a ceramic wiring board, and to mount a gallium-arsenide semiconductor element.

[0005]

The composition for a ceramic substrate according to the present invention comprises a crystallized glass material and 5 to 50% by weight of zirconia particles, and the crystallized glass material and the zirconia particles have a nanocomposite structure. Is formed.
In the composition for a ceramic substrate, the average particle diameter of the zirconia particles is preferably 0.01 to 0.4 μm. The ceramic substrate according to the present invention comprises a crystallized glass material and 5 to 50% by weight of zirconia particles, and the composition for a ceramic substrate, wherein the crystallized glass material and the zirconia particles form a nanocomposite structure, or A composition for a ceramic substrate comprising a crystallized glass material and 5 to 50% by weight of zirconia particles having an average particle diameter of 0.01 to 0.4 μm, and wherein the crystallized glass material and the zirconia particles form a nanocomposite structure. And a wiring substrate formed on the ceramic substrate.

[0006]

In the composition for a ceramic substrate according to the present invention, a crystallized glass material can form a substrate having a small dielectric constant. Further, since the zirconia particles are contained in an amount of 5 to 50% by weight, a ceramic substrate having a coefficient of thermal expansion similar to that of a gallium-arsenic semiconductor element can be obtained. Further, since the crystallized glass material and the zirconia particles form a nanocomposite structure, a ceramic substrate having higher mechanical strength can be obtained. Further, the average particle diameter of the zirconia particles is 0.01 to
When it is 0.4 μm, a ceramic substrate with further improved mechanical strength can be obtained.

[0007] The ceramic wiring board according to the present invention is composed of the above-described composition for a ceramic substrate, and thus has a low dielectric constant. Further, since the coefficient of thermal expansion is close to that of the gallium-arsenic semiconductor element, the gallium-arsenic semiconductor element can be mounted. Furthermore, the mechanical strength is high, and even when the gallium-arsenic semiconductor element is mounted and then cooled to an extremely low temperature, damage to the gallium-arsenic semiconductor element, damage to the insulating substrate, or peeling of the semiconductor element hardly occurs.

[0008]

1 and 2 show a multilayer circuit board as an embodiment of the ceramic wiring board of the present invention. In the figure, a multilayer circuit board 1 includes a plate-shaped substrate body 2 which is a ceramic substrate made of a ceramic composition containing a crystallized glass material and zirconia particles, an internal wiring layer 3 formed in the substrate body 2, It mainly includes a surface wiring layer 4 provided on the surface of the substrate body 2 and a gallium-arsenic semiconductor element 5 connected to the surface wiring layer 4.

The substrate body 2 has a substantially rectangular plate shape. As shown in FIG. 2, for example, eight ceramic green sheets are laminated and integrally fired to form integrated sheets 2a, 2b, 2c, 2d, 2e, 2f, 2g,
2h. The internal wiring layer 3 is formed of each sheet 2
a. A predetermined internal wiring pattern is formed between 2h. The internal wiring layer 3 provided on each of the sheets 2a.
The sheets 2a... 2h are connected by conductive through holes 6 penetrating in the thickness direction. The internal wiring layer 3 including the through holes 6 is formed using a copper-based conductor material. Note that a gold-based or silver-based conductor material can be used instead of the copper-based conductor material. As the silver-based conductor material, for example, a conductor material such as silver-palladium, silver-platinum, or silver-palladium-platinum is used.

The surface wirings 4 are formed on both main surfaces of the substrate main body 2 in a predetermined high-density pattern, and have a conductive property penetrating in the thickness direction of the sheets 2a and 2h constituting both main surfaces of the substrate main body 2. The through hole 7 is connected to the internal wiring layer 3. The surface wiring 4 is made of a copper-based conductor material that hardly causes migration. Examples of such a copper-based conductor material include QS19 manufactured by DuPont.
0 can be exemplified.

The gallium-arsenic semiconductor element 5 is mounted on the main surface of the substrate body 2 and connected to the surface wiring 4 by solder 8. In the multilayer circuit board 1, the sheets 2a... 2h of the substrate body 2 are formed of a ceramic substrate composition containing a crystallized glass material and zirconia particles. The crystallized glass material contained in this composition is, for example, a powder of crystallized glass having a low dielectric constant such as cordierite-based crystallized glass, anorthite-based crystallized glass, and wollastonite-based crystallized glass. The composition of each crystallized glass may be a general one, and is not particularly limited. For example, cordierite-based crystallized glass is
It contains 10 to 40% by weight of alumina, 5 to 20% by weight of magnesia, and 35 to 45% by weight of silica.

Specific examples of the crystallized glass material include those having the compositions shown in Table 1.

[0013]

[Table 1]

[0014] Such a crystallized glass powder is 900-
Since it can be fired at 1050 ° C., it can be fired at the same time as a conductive material for low-temperature firing such as gold, silver, and copper. The preferred particle size of the crystallized glass powder is 0.1 to 5.0 μm,
More preferably, it is 2.0 μm or less. The zirconia particles are represented by ZrO ₂ and are components for adjusting the thermal expansion coefficient of the above-mentioned crystallized glass material to approximate the thermal expansion coefficient of the gallium-arsenic semiconductor element 5. Preferred as the zirconia particles are tetragonal zirconia particles. The tetragonal zirconia particles change from tetragonal to monoclinic when stress is applied, and can absorb the stress, so that the mechanical strength and toughness of the substrate body 2 can be increased.

The zirconia particles are dispersed between or in the crystals of the crystallized glass material. When the zirconia particles are dispersed between the crystals of the crystallized glass material, the zirconia particles and the crystallized glass are preferably mixed to form a nanocomposite structure. Here, the nanocomposite structure refers to a structure in which the crystallized glass material powder and the zirconia particles are sufficiently dispersed, and the zirconia particles surround each crystallized glass material powder particle. Such a nanocomposite structure can be realized by adding a dispersant to a mixture of the zirconia particles and the crystallized glass material powder and sufficiently mixing the mixture with a dispersion mixer such as a ball mill. When using a composition having a nanocomposite structure,
A substrate body having better mechanical strength is obtained.

In this case, the average particle size of the zirconia particles is 0.4 μm or less, preferably 0.1 μm or less. When the average particle diameter exceeds 0.4 μm, the effect of the nanocomposite structure is reduced. In particular, in the case of tetragonal zirconia particles, the stability as tetragonal crystal is reduced,
The effect of improving the mechanical strength of the substrate body 2 is reduced. The lower limit of the average particle diameter of the zirconia particles is not particularly limited, but is generally 0.01 μm, which is the production limit.

The crystallized glass material powder in which the zirconia particles are dispersed in the crystal is obtained by adding the zirconia particles during a melting step for producing the crystallized glass material, and then pulverizing the zirconia particles. The above-mentioned zirconia particles are contained in the composition for a ceramic substrate in an amount of 5 to 50% by weight, preferably 1 to 50% by weight.
0 to 30% by weight. When the addition amount is less than 5% by weight, the mechanical strength of the substrate main body 2 decreases. Conversely, if the content exceeds 50% by weight, the sintering temperature of the composition increases, and the dielectric constant of the substrate body 2 increases.

In the multilayer circuit board 1, the board body 2
Is composed of the above-described composition for a ceramic substrate, and thus has a low dielectric constant. Further, since the internal wiring layer 3 and the surface wiring 4 are made of a low-resistance conductive material, the resistance value is small. Therefore, in the internal wiring layer 3 and the surface wiring 4, the signal propagation speed is high. Further, since the composition for a ceramic substrate contains a predetermined amount of zirconia particles, the coefficient of thermal expansion of the substrate body 2 is close to the coefficient of thermal expansion of the gallium-arsenic semiconductor element 5. Therefore, even when the multilayer circuit board 1 on which the gallium-arsenide semiconductor element 5 is mounted is cooled to an extremely low temperature of about -196 ° C., the gallium-arsenic semiconductor element 5 is damaged, the substrate body 2 is damaged, or the semiconductor element 5 is damaged. Less likely to peel.

Next, a method of manufacturing the multilayer circuit board 1 according to one embodiment of the present invention will be described. First, the substrate body 2 is prepared. When manufacturing the substrate body 2, first, a plurality of ceramic green sheets are prepared. The ceramic green sheet can be fired by adding a binder and a solvent to the above-mentioned ceramic substrate material to prepare a slurry, and forming the slurry into a sheet by a doctor blade method or a calendar roll method. At this time, the thickness of the ceramic green sheet is preferably set to 0.1 to 0.5 mm.

Next, holes for forming the through holes 6 and 7 are formed in predetermined portions of each ceramic green sheet by a method such as punching. The diameter of this hole should be between 0.2 and
Preferably, it is set to 0.5 mm. Next, copper paste is filled into the holes provided in the ceramic green sheet. As the copper paste, a paste containing the above-described copper-based material, glass frit, and an organic vehicle is used. In particular, a copper powder having an average particle size of 3 to 5 μm and a sag point of 700 to 85
A glass frit at 0 ° C. and ethyl cellulose and 2,2,4-trimethyl
A mixture obtained by kneading an organic vehicle containing 1,3-pentanediol monoisobutyrate into a paste using three rolls is used.

Next, a predetermined internal wiring pattern is formed on the surface of the ceramic green sheet having the holes filled with the copper paste. The internal wiring pattern can be formed by printing the same copper paste as described above by a screen printing method. Next, the ceramic green sheets on which the internal wiring patterns are formed are stacked in a predetermined order and pressed to produce a green sheet laminate. The pressing condition of the ceramic green sheet is 50 to 250 kg / cm ² at 80 to 150 ° C.
It is preferable to set In the green sheet laminate, each ceramic green sheet is pressed by the internal wiring pattern and plastically deformed at the time of pressure bonding, so that the ceramic green sheets are in close contact with each other at a portion where the internal wiring pattern is not formed. Also, each internal wiring pattern is pressed against the copper paste filled in the hole of the adjacent ceramic green sheet.

When such a green sheet laminate is fired in a neutral atmosphere, the substrate body 2 is obtained. In this case, since the ceramic green sheet is made of a composition for a ceramic substrate containing a crystallized glass material, it can be fired at a low temperature of about 1000 ° C. Next, the above-mentioned copper-based material is printed on the main surface of the substrate main body 2 in a predetermined pattern of the surface wiring 4 by a screen printing method and fired. Thereby, a surface wiring is formed.

[Other Embodiments] In the above embodiment, the composition for a ceramic substrate of the present invention was used for a multilayer circuit board. However, the composition for a ceramic substrate of the present invention may be used for a package for housing a semiconductor element. Can be. [Experimental Example] Experimental Example 1 Tetragonal zirconia particles (average particle size: 0.1 μm) or alumina particles (average particle size: 2.0 μm) were added to the crystallized glass material A shown in Table 1 at a ratio shown in Table 2, A composition for a ceramic substrate was obtained. Then, a substrate is prepared using the composition for a ceramic substrate, and a dielectric constant,
The coefficient of thermal expansion and the three-point bending strength were examined. Table 2 shows the results. In addition, the test method of a dielectric constant, a thermal expansion coefficient, and a three-point bending strength is as follows. (Dielectric constant) This was performed according to the bridge circuit method. The bridge circuit method is a method of measuring a complex impedance of a sample and obtaining a dielectric constant and tan δ of the sample. (Coefficient of thermal expansion) The change in the sample caused by heating or cooling was measured by the linear displacement of the probe to which a load was applied. The linear displacement was converted to an electrical signal by a differential transformer and recorded with temperature and time (isothermal measurement).

The coefficient of thermal expansion of the gallium-arsenide semiconductor device is 5.6 to 6.0 × 10 ⁻⁶ / ° C. (Three-point bending strength) The test piece was placed on two fulcrums arranged at a fixed distance, and a maximum bending stress was measured when a load was applied to a central point between the fulcrums and the fulcrum was broken.

[0025]

[Table 2]

Experimental Example 2 30% by weight of tetragonal zirconia particles having an average particle size shown in Table 3 were added to the crystallized glass material A shown in Table 1 to obtain a composition for a ceramic substrate. Then, a substrate was prepared using this composition, and the three-point bending strength of this substrate was examined in the same manner as in Experimental Example 1. Table 3 shows the results.

[0027]

[Table 3]

[0028]

Since the composition for a ceramic substrate according to the present invention contains a crystallized glass material and 5 to 50% by weight of zirconia particles, the dielectric constant is small and the thermal expansion coefficient is a gallium-arsenic semiconductor device. Therefore, a ceramic substrate on which a gallium-arsenic semiconductor element can be mounted can be provided. Further, since the crystallized glass material and the zirconia particles form a nanocomposite structure, a substrate having high mechanical strength can be formed. Further, when the average particle diameter of the zirconia particles is 0.01 to 0.4 μm, a ceramic substrate with further improved mechanical strength can be obtained.

Since the ceramic wiring substrate according to the present invention is composed of a ceramic substrate composition containing a crystallized glass material and 5 to 50% by weight of zirconia particles, the dielectric constant is small and the thermal expansion coefficient is gallium-arsenic semiconductor. Since it is similar to the element and has high mechanical strength, it is possible to obtain a ceramic wiring board suitable for mounting a gallium-arsenic semiconductor element.

[Brief description of the drawings]

FIG. 1 is a perspective view of a multilayer circuit board employing an embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional view taken along the line II-II of FIG.

[Explanation of symbols]

 Reference Signs List 1 multilayer circuit board 2 board main body 3 internal wiring layer 4 surface wiring

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 23/14 H05K 1/03 C04B 35/48

Claims (3)

(57) [Claims] 1. A glass-ceramic material and 5 to 50% by weight of di-
Luconia particles, and the crystallized glass material
Luconia particles form nanocomposite structure
A composition for a ceramic substrate, comprising: 2. The zirconia particles having an average particle diameter of 0.0
The composition for a ceramic substrate according to claim 1, wherein the composition has a thickness of 1 to 0.4 m . 3. A ceramic wiring board, comprising: a ceramic substrate comprising the ceramic substrate composition according to claim 1 ; and a wiring layer formed on the ceramic substrate.