JP2892220B2 - Manufacturing method of ceramic wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic wiring board suitably used for a circuit wiring board on which a semiconductor element is mounted and a semiconductor element housing package for housing the semiconductor element.

[0002]

2. Description of the Related Art Conventionally, a ceramic wiring board used for a circuit wiring board on which a semiconductor element or the like is mounted, a semiconductor element housing package for housing the semiconductor element, or the like, includes an insulating base made of an aluminum oxide sintered body; A wiring conductor layer made of copper which is baked on the surface of the insulating base.

[0003] Such a conventional ceramic wiring board is usually
Screen printing of a conductive paste obtained by adding and mixing a glass frit made of zinc oxide, boron oxide, silicon oxide, etc., and a suitable binder and solvent to copper powder on the surface of an aluminum oxide sintered body with excellent electrical insulation By applying a thick film forming technique such as a printing method, a predetermined pattern is printed and applied, and then fired at a temperature of about 900 ° C. in a reducing atmosphere to melt the glass frit and pass through the melted glass frit. It is manufactured by bonding copper powder to the surface of an insulating substrate.

However, the ceramic wiring board used for the conventional circuit wiring board or the package for accommodating the semiconductor element has a low thermal conductivity of 20 W / m · K in which the insulating base is made of an aluminum oxide sintered body. In recent years, when high-density and high-integration technologies have been developed and semiconductor devices that generate a large amount of heat are mounted and housed, the circuit wiring board and the semiconductor device housing package generate heat generated by the semiconductor devices. The disadvantage is that the semiconductor element cannot be satisfactorily released into the atmosphere and is heated to a high temperature by the heat generated by the semiconductor element, causing thermal destruction of the semiconductor element or thermal degradation of the characteristics, resulting in malfunction of the semiconductor element. Had.

In order to solve the above-mentioned drawbacks, the insulating base of a ceramic wiring board used for a circuit wiring board or a package for accommodating a semiconductor element has a high thermal conductivity and can satisfactorily release heat to the atmosphere. It is conceivable to form the aluminum nitride sintered body.

[0006]

However, when the insulating substrate of the ceramic wiring substrate is formed of an aluminum nitride sintered body, the aluminum nitride sintered body is non-oxide and the surface of the insulating substrate has a weak polarity. Therefore, when the copper powder is bonded to the surface of the insulating base via the glass frit to apply the conductive layer, the bonding strength between the glass frit and the insulating base is low, and as a result, the conductive layer for wiring is formed on the surface of the insulating base. Caused a drawback that it could not be firmly adhered to.

[0007]

The present inventors conducted various experiments in view of the above drawbacks. As a result, the conductor paste contained a predetermined amount of lead and at least one nitrate or peroxide of an element of the second group of the periodic table. When the conductive paste is used to form a conductive layer for wiring on the surface of the insulating base using the conductive paste, the glass frit in the conductive paste wets (reacts) well on the insulating base,
As a result, it has been found that the conductor layer for wiring can be firmly adhered and bonded to the surface of the insulating base made of non-oxide ceramics.

According to the present invention, based on the above findings, a conductor layer for wiring is firmly bonded to the surface of an insulating base made of non-oxide ceramics, and a semiconductor element to be mounted and accommodated can be normally and stably maintained for a long period of time. It is an object of the present invention to provide a method of manufacturing a ceramic wiring board that can be operated.

[0009]

According to the present invention, a conductive paste containing copper powder and glass frit is applied to the surface of an insulating substrate made of non-oxide ceramics by a thick film forming technique and fired in a reducing atmosphere. And a method of manufacturing a ceramic wiring board by forming a thick film conductor layer made of copper on the surface of an insulating substrate, wherein said conductor paste contains lead and nitrate of an element belonging to Group 2 of the periodic table. Or at least one of peroxides is 0.1 to 3.0 wt% by external addition
It is characterized by being contained.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIGS. 1 (a), 1 (b) and 1 (c) are cross-sectional views for explaining the steps of a method for manufacturing a ceramic wiring board according to the present invention.

First, the ceramic wiring board of the present invention is shown in FIG.
As shown in (1), an insulating substrate 1 made of an aluminum nitride sintered body is prepared.

The insulating substrate 1 made of the aluminum nitride sintered body is made of, for example, aluminum nitride (AlN), erbium oxide (Er ₂ O ₃ ), ytterbium oxide (Yb ₂ O ₃ ).
A suitable binder and a solvent are added to the raw material powder and mixed to form a slurry, and a ceramic green sheet (ceramic green sheet) is formed by adopting a conventionally known doctor blade method or calender roll method. Thereafter, the ceramic green sheet is obtained by subjecting the ceramic green sheet to suitable punching and firing at a high temperature (about 1800 ° C.).

Since the thermal conductivity of the aluminum nitride sintered body constituting the insulating base 1 is as high as 150 W / m · K, a semiconductor element is mounted on the insulating base 1 and the semiconductor element transfers heat. Even if the heat is generated, the heat generated by the semiconductor element is absorbed by the insulating base 1 and satisfactorily released into the atmosphere, and the semiconductor element is never heated to a high temperature that causes thermal destruction or a change in characteristics.

Next, as shown in FIG. 1 (b), a wiring pattern 2 is formed on the insulating substrate 1 on its upper surface. The wiring pattern 2 insulates a conductive paste obtained by adding and mixing a glass frit, lead and at least one of a nitrate or a peroxide of an element of the second group of the periodic table, a binder and a solvent to copper powder. The upper surface of the base 1 is adhered in a predetermined pattern on the upper surface of the insulating base 1 by printing and applying a known thick film forming technique such as a screen printing method.

As the glass frit added to the conductor paste, zinc oxide (ZnO) 15.0% by weight and lead oxide (P
bO) 45.0% by weight, silicon oxide (SiO ₂ ) 10.0% by weight, boron oxide (B ₂ O ₃ ) 30.0% by weight glass is used,
Ethyl cellulose and alpha-terpineol are added as a binder and a solvent. The conductive paste is, for example, 15.0% by weight of zinc oxide (ZnO), 45.0% by weight of lead oxide (PbO), 10.0% by weight of silicon oxide (SiO ₂ ) in 100 g of copper powder.
5% by weight of glass frit consisting of 30.0% by weight of boron oxide (B ₂ O ₃ )
0.1 to 3.0% by weight of (Pb ₃ O ₄ ), 2 g of ethyl cellulose as a binder and 16 g of alpha-terpineol as a solvent are added thereto, and these are kneaded about 8 to 10 times by a kneader of three rolls. Formed by

Then, the insulating substrate 1 on which the wiring pattern 2 is adhered on the upper surface is fired in a reducing atmosphere at a temperature of about 900 ° C., and the copper powder in the wiring pattern 2 is put on the surface of the insulating substrate 1 via a glass frit. Fig. 1 (c)
As shown in (1), a ceramic wiring board in which a conductor layer 3 for wiring is applied to the upper surface of an insulating base 1 is completed. In this case, the conductive paste for forming the wiring pattern 2 contains lead peroxide, and since the bonding between the glass frit and the insulating substrate 1 is improved by the lead peroxide, the conductive layer 3 for wiring is formed. Is extremely firmly adhered to the upper surface of the insulating substrate 1.

If the content of lead peroxide contained in the conductor paste is less than 0.1% by weight, the conductor layer 3 for wiring cannot be firmly adhered to the surface of the insulating base 1, and If the content exceeds 3.0% by weight, an oxide is generated on the surface of the copper powder in the wiring conductor, and the adhesion of the copper powder to the surface of the insulating substrate 1 is weakened. Therefore, the content of lead peroxide contained in the conductor paste is specified in the range of 0.1 to 3.0% by weight.

The conductive layer for wiring may be formed by plating a metal having good conductivity and excellent corrosion resistance, such as nickel or gold, to a thickness of 1.0 to 20.0 μm by plating. Satisfactorily electrically connects the electrodes of the semiconductor element to the conductive layer while effectively preventing oxidative corrosion of the semiconductor element. Therefore, the conductive layer is formed of a highly conductive metal such as nickel or gold and a metal having excellent corrosion resistance on the surface by a plating method of 1.0 to 1.0.
It is preferable to coat the layer to a thickness of 20.0 μm.

Furthermore, in the above embodiment, lead peroxide was used as an example of lead contained in the conductor paste and nitrate or peroxide of an element belonging to Group 2 of the periodic table. However, strontium nitrate (Sr (NO ₃ ) ₂ ) or lead nitrate (Pb (NO ₃ ) ₂ ).

(Experimental Example) Next, the operation and effect of the present invention will be described based on the experimental examples described below. First, 15.0% by weight of zinc oxide (ZnO), 45.0% by weight of lead oxide (PbO), 10.0% by weight of silicon oxide (SiO ₂ ) were added to copper powder so as to have the composition shown in Table 1.
A glass frit composed of 30.0% by weight of boron oxide (B ₂ O ₃ ), lead peroxide (Pb ₃ O ₄ ), 16 g of ethyl cellulose as a binder and alpha-terpineol as a solvent are added and mixed to obtain a conductor paste sample.

Next, each of the conductor paste samples is printed and applied to the surface of an insulating substrate made of an aluminum nitride sintered body to a length of 2 mm, a width of 2 mm and a thickness of 15 μm by a screen printing method.
Thereafter, this is fired in a nitrogen atmosphere at a temperature of 900 ° C., and a conductor layer for wiring is deposited on the surface of the insulating substrate.

Finally, the molten solder (
(Tin: 60% by weight, Lead: 38% by weight, Silver: 2% by weight), dipped with a tin-plated copper wire, and immediately thereafter and at a high temperature of 125 ° C for 48 hours, 240 hours
After standing for a time, the conductor was pulled in a direction perpendicular to the surface of the insulating base, and the tensile strength when the conductor layer was peeled off from the insulating base was examined and evaluated as the adhesion strength between the conductor layer and the insulating base.

In Table 1, Sample No. 1 is a conventional and generally used conductive paste obtained by adding a glass frit, a binder and a solvent to copper powder and mixing them.

In the above evaluation, the number of the conductor layers to be attached to the insulating substrate was set to 20, and the average value was defined as the adhesion strength between the conductor layer and the insulating substrate.

The results are shown in Table 1.

[0026]

[Table 1]

[0027]

As can be seen from the above experimental results, a conductor layer for wiring formed by using a conductor paste obtained by adding and mixing a glass frit, a binder and a solvent to conventional copper powder is made of non-oxide ceramics. When the adhesion strength between the insulating base and the wiring conductor layer is left at high temperature for 240 hours,
0.60 kg / m ² or less, which is extremely weak, whereas the copper powder of the present invention, that is, at least one of glass frit and lead and nitrate or peroxide of an element of the second group of the periodic table is added to the copper powder. When a conductor layer for wiring is formed using a conductor paste in which one kind, a binder and a solvent are added and mixed, the adhesion strength between the insulating base made of non-oxide ceramics and the conductor layer for wiring is left at high temperatures Even after this, it was extremely strong at 1.0 kg / m ² or more, indicating that the wiring conductor layer was firmly adhered to the insulating base.

Therefore, the ceramic wiring board manufactured by the manufacturing method of the present invention is suitably used for a circuit wiring board for mounting and housing a semiconductor element generating a large amount of heat and a package for housing a semiconductor element.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of each process for describing a method for manufacturing a ceramic wiring board of the present invention.

[Explanation of symbols]

 1 ····· Insulating substrate 2 ····· Wiring pattern 3 ····· Conductor layer for wiring

Claims (1)

(57) [Claims] 1. A conductive paste containing copper powder and glass frit is applied to the surface of an insulating substrate made of non-oxide ceramics by a thick film forming technique and fired in a reducing atmosphere to form a copper paste on the surface of the insulating substrate. A method of manufacturing a ceramic wiring board, comprising: forming a thick-film conductor layer comprising: a conductive paste containing at least one of lead and a nitrate or peroxide of an element of Group 2 of the periodic table. A method for producing a ceramic wiring board, comprising 0.1 to 3.0% by weight of seeds by external addition.