JP2001122680A - Glass ceramic substrate and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass ceramic substrate having improved resistance to a plating liquid, which is produced while the firing temperature at a temperature of <=950 deg.C is maintained, thereby adverse effects on substrate strength and dimensions are suppressed. SOLUTION: In a glass ceramic substrate, which is obtained by forming via conductors and a wiring film in green sheets, each containing a glass component and an inorganic filler, then laminating a pltirality of the green sheets, and firing the laminated sheets at 700 to 950 deg.C, a glass ceramic film having high resistance to a plating liquid and thickness of 3 to 15 μm, preferably 5 to 10 μm is provided on the outermost layer of the glass ceramic substrate mentioned above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass ceramic substrate having a resistance to a plating solution and a method for manufacturing the same.

[0002]

2. Description of the Related Art Unlike an alumina substrate which needs to be fired at a temperature of 1500 ° C. or more, a glass ceramic substrate made of a mixture of glass powder and an inorganic filler such as alumina powder is obtained by firing at a temperature of 950 ° C. or less. Therefore, simultaneous sintering with a metal such as Ag or Au having a low melting point is possible.
Since the wiring can be formed using these metals, there is an advantage that the conductivity of the wiring is high.

[0003] Further, a capacitor or a resistor can be built in the substrate, so that it is attracting attention as a substrate suitable for miniaturization and multifunctionalization.

An Ag paste, a paste mainly containing Ag and Pd mixed therein, and a Pt mainly containing Ag as a wiring material to be printed on the surface of a glass ceramic substrate are used.
Paste or a Cu paste. In order to mount electronic components on wirings obtained by applying and baking these pastes, it is common to bond them with solder. However, Ag-based wirings have a problem that they are easily dissolved in solder. . Further, in the case of Cu, there is a problem that the solder wettability is likely to be deteriorated due to surface oxidation of Cu, for example. Further, there is another problem that Sn in the solder diffuses into Ag or Cu for a long time to form a brittle intermetallic compound, thereby impairing reliability.

[0005] In order to solve these problems, it is common practice to apply Ni or further Au plating on the wiring. However, these plating solutions are often acidic or alkaline, and even if they are almost neutral, the glass ceramic substrate is eroded by the plating solution and the adhesion between the wiring and the glass ceramic substrate is impaired, or the substrate surface is damaged. There is a problem that the risk of becoming brittle is high.

In order to solve this problem, the glass contained in the glass ceramic substrate is made of SiO ₂ , Al ₂ O ₃ , ZrO ₂
It is conceivable to make the composition excellent in plating solution resistance as a composition rich in components such as
In order to satisfy the conditions of setting the firing temperature to 950 ° C. or less and further maintaining sufficient strength as a substrate, Zn
It must be formed using glass containing a large amount of components such as O, PbO, oxides of alkaline earth metals, and B ₂ O ₃ , and the plating solution resistance cannot be improved.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and maintains a firing temperature of 950 ° C. or less, minimizes the influence on substrate strength and dimensions, and reduces plating solution resistance. It is an object of the present invention to provide an improved glass ceramic substrate.

[0008]

According to a first aspect of the present invention, a via conductor and a wiring film are formed on a green sheet containing a glass component and an inorganic filler, and a plurality of the green sheets are laminated. In a glass ceramic substrate formed by firing at ~ 950 ° C, a thickness of 3 ~ 15μ is formed on the outermost layer surface of the glass ceramic substrate.
m, preferably a glass ceramic film having a high plating solution resistance of 5 to 10 μm.

In the second invention, a plurality of green sheets on which via conductors and wiring films are formed are stacked,
In a method of obtaining a glass-ceramic substrate by firing at 00 to 950 ° C., a green sheet to be an outermost layer of the glass-ceramic substrate is coated on one surface of the green sheet with a glass-ceramic slurry having a composition rich in plating solution resistance. Forming a second glass ceramic green sheet film by drying, forming a via hole, filling and printing a conductive paste in the via hole and the surface of the second glass ceramic film to form a via conductor; And a step of forming a conductor film to be a wiring.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the glass ceramic substrate used in the present invention has a glass ceramic film having excellent plating solution resistance on its surface, and therefore has an effect on plating solution resistance, and Since the film is as thin as 15 μm or less, the influence on substrate strength and dimensions is minimized. Further, as the manufacturing process, the conventional glass ceramic material and the process can be used as they are, so that the economic efficiency is not impaired.

As a means for minimizing the influence on the strength and dimensions of the substrate, it is preferable to minimize the thickness of the glass ceramic film having high plating solution resistance, but it is necessary to have a thickness sufficient to sufficiently coat the substrate surface. So, the thickness after firing is 3 ~
It is 15 μm, preferably 5 to 10 μm.

The glass ceramic green sheet film having high plating solution resistance provided in the outermost layer may be made of glass powder having high plating solution resistance alone or a mixed powder of glass powder and a powder of alumina, zirconia, etc., ethyl cellulose, acryl, butyral, etc. The resin is mixed with a solvent such as terpineol, ethanol, toluene or the like to form a slurry, and the slurry is formed by spraying, screen printing, or doctor blade method.

Since the plating solution resistance varies depending on the acidity or alkalinity of the plating solution or components, it is necessary to select a glass composition according to the plating solution. Further, it is preferable that the softening point (° C.) of the glass of the glass ceramic substrate body and the glass of the glass ceramic film be as close as possible, but it does not hinder the discharge of gas generated by decomposition of the resin of the green sheet during firing. And any glass softening point that sufficiently densifies at the sintering temperature.
It can be used if it is in the range of 850 ° C.

In the green sheet on which the glass ceramic film having excellent plating solution resistance is formed, a via hole is opened using, for example, a mold, and a conductive film is formed in the via hole and on the surface of the second glass ceramic film. The conductive paste is filled and printed to form a via conductor and a conductor film to be a wiring.

The green sheet of the inner layer is processed in the same manner as described above except that a glass ceramic film is formed, and the required number of sheets are laminated to form a green sheet at 60 to 80 ° C. and 50 to 500 kg / cm ^2.
Under pressure, the pressure is integrated. And 300-500
Decompose and remove the green sheet resin in the temperature range of 7 ° C.
The glass ceramic substrate is completed by sintering at 00 to 950 ° C.

[0016]

Next, the present invention will be further described with reference to examples. (Examples 1, 2, 3, and 4) The slurry for producing the glass ceramic substrate was SiO ₂ : 2 on a weight% basis.
3, Al ₂ O ₃ : 23, ZnO: 27, B ₂ O ₃ : 14, C
aO: 13 composition, 50 parts by weight of glass powder having an average particle diameter of 2.2 μm and 50 parts by weight of alumina powder having an average particle diameter of 1.7 μm, 9 parts by weight of polyvinyl butyral and 7 parts by weight of diisobutyl phthalate Oleic acid, 1 part by weight of oleic acid, 40 parts by weight of isopropyl alcohol, and 20 parts by weight of trichloroethane, and mixed by a ball mill for 24 hours. Using the obtained slurry, a green sheet having a thickness of 120 μm was formed by a doctor blade method.

On the other hand, as a slurry for preparing a plating-resistant glass layer, SiO ₂ : 76,
Al ₂ O ₃ : 5, B ₂ O ₃ : 8, ZrO ₂ : 1, Li ₂ O:
4, Na ₂ O: 4, TiO ₂ : 2, glass powder having an average particle size of 1.2 μm, and ethyl cellulose 6% by weight
And a terpineol solution were kneaded with a three-roll mill.
The glass softening point is 780 ° C. for the green sheet and 822 ° C. for the plating solution.

The above plating-resistant liquid glass slurry was applied to the entire surface of the green sheet corresponding to the surface exposed as the surface of the glass ceramic substrate by a screen printing method. The thickness of the coating film after drying was 11 μm.

Next, via holes were formed in the green sheet by the NC punching method. Then, an Ag paste was filled in the via holes by screen printing, and further, wirings were formed by printing. The inner green sheet is processed in the same manner as described above, except that a glass ceramic film is formed, a via hole and a wiring are provided, and the number of inner green sheets is set to 2 (Example 1) and 4 (Example 2), respectively. , 6 (Example 3), 8

(Embodiment 4)
Kg / cm ² , pressurized under the conditions of 5 minutes, and integrated to form a laminate. A razor was pressed onto the lattice obtained as described above to form a lattice-like slit having a depth of about 50 μm. The size of the grid is 17.44 m in both X and Y directions
m.

Thereafter, the laminate is placed in an electric furnace,
The temperature was raised to 0 ° C. at a rate of 2 ° C./min, and held for 1 hour to thermally decompose and remove the resin of the green sheet.
The temperature was raised to 5 ° C / min at 5 ° C / min.
Cooled down over time. After baking, it was divided along the slit. In addition, the thickness of the plating solution glass slurry coating film after firing was 7 μm.

Thereafter, the following evaluation was performed. Dimensions: Measurement of external dimensions. ――― Measured using calipers. Corrosion resistance: After immersion in 1% hydrochloric acid aqueous solution at 25 ° C, activated with Pd, and added to 80 ° C electroless nickel plating solution (pH 4)
By immersing for 0 minutes, a nickel film having a thickness of 6 μm was deposited on the Ag wiring. The adhesion time (Kg / mm ² ) of the electrode was measured by changing the immersion time in the aqueous hydrochloric acid solution, and this value was determined as a substitute for corrosion resistance and compared. The evaluation was performed using each of the examples, and an average value was obtained at each immersion time. Table 1 shows the measurement results of the dimensions, and Table 2 shows the results of the corrosion resistance.

(Comparative Examples 1, 2, 3, 4) For comparison,
A substrate without a plating solution glass ceramic film was prepared in the same manner as in the example, and the same evaluation as in the example was performed. Table 1 also shows the measurement results of dimensions, and Table 2 also shows the results of corrosion resistance.

(Examples 5, 6, 7, 8, 9) The thickness of the coating solution of the glass slurry after plating was 3 (Example 5).
5 (Example 6), 7 (Example 7), 10 (Example 8),
A glass ceramic substrate was obtained in the same manner as in Example 1 except that the thickness was 15 μm (Example 9) and the number of green sheets in the inner layer was eight. The corrosion resistance was evaluated in the same manner as in Example 1 using the obtained substrate. Table 3 shows the results of the obtained corrosion resistance at the immersion time of 1 minute.

(Comparative Examples 5 and 6) Except that the thickness of the plating-resistant liquid glass film after firing was 1 (Comparative Example 5) and 17 (Example 6) μm and the number of green sheets in the inner layer was 8 A glass ceramic substrate was obtained in the same manner as in Example 1. Using the obtained substrate, the dimensional accuracy and corrosion resistance were evaluated in the same manner as in Example 1. The results of the corrosion resistance obtained at the immersion time of 1 minute are shown in Table 3.

Table 1 Dimensional results Invention example Comparative example Inner layer green Average σ Remarks Average σ Remarks Number of sheets (mm) (mm) (mm) (mm) 2 15.02 0.02 Example 1 15.02 0.02 Comparative example 1 15.04 0.02 Example 2 15.06 0.03 Comparative Example 2 6 15.06 0.06 Example 3 15.08 0.07 Comparative Example 3 8 15.09 0.07 Example 4 15.10 0.08 Comparative Example 4

Table 2 Corrosion resistance (adhesion strength N / mm ² ) Corrosion resistance (adhesion strength N / mm ² ) 1% hydrochloric acid aqueous solution immersion time (min) Example Comparative example 0 15.7 17.6 0.5 15.7 10.8 1.0 14.7 5.9 2 0.0 14.7 2.9 5.0 12.7 <1.0

Table 3 Corrosion Resistance (Adhesion Strength N / mm ² ) and Dimensional Accuracy Plating Solution Corrosion Resistance Dimensional Accuracy Glass Film Thickness Average σ (μm) (N / mm ² ) (mm) (mm) Example 5 3 12.7 15.10 0.07 Example 6 5 14.7 15.10 0.06 Example 7 7 14.7 15.09 0.08 Example 8 10 14.7 15.09 0.08 Example 9 15 14.7 15.08 0.09 Comparative example 5 1 9.8 15.10 0.07 Comparative example 17 17 14.7 15.09 0.12

Table 1 shows that the method of the present invention has almost no effect on the dimensions. Further, Table 2 shows that the longer the sample is immersed in the aqueous hydrochloric acid solution in the comparative example, the more the substrate is eroded and the lower the adhesion strength is.

According to Table 3, the thickness of the plating-resistant liquid glass film is 3
If it is at least 5 μm, preferably at least 5 μm, sufficient plating solution resistance can be obtained. However, when the thickness exceeds 10 μm, the dimensional accuracy is slightly deteriorated, and when the thickness exceeds 15 μm, the dimensional accuracy is significantly deteriorated. Therefore, it is desired that the thickness of the plating-resistant glass film be within the range of the present invention.

[0031]

As described above, by simply adding the step of applying plating-resistant glass to the conventional method of manufacturing a glass-ceramic substrate, a glass-ceramic substrate having excellent corrosion resistance can be formed without affecting the dimensions and the like. We were able to.

Claims (3)

[Claims] 1. A glass ceramic substrate formed by forming a via conductor and a wiring film on a green sheet containing a glass component and an inorganic filler, laminating a plurality of the green sheets, and firing at 700 to 950 ° C. The thickness after firing is 3 on the outermost layer surface of the glass ceramic substrate.
A glass ceramic substrate provided with a glass ceramic film having a high plating solution resistance of up to 15 μm. 2. A glass ceramic substrate provided on the outermost layer surface of the glass ceramic substrate, wherein the glass ceramic film having high plating solution resistance has a thickness of 5 to 10 μm after firing. 3. A method for obtaining a glass ceramic substrate by laminating a plurality of green sheets on which a via conductor and a wiring film are formed, and firing the green sheets at 700 to 950 ° C. Forming a second glass-ceramic green sheet film by applying a glass-ceramic slurry having a composition rich in plating solution to one surface of the green sheet and drying the glass-ceramic slurry, forming a via-hole; And the second
A method of filling a conductive paste on the surface of the glass ceramic film, printing the conductive paste, and forming a conductive film to be a via conductor and a wiring.