JPH11307895A - Wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to securely and electrically connect a semiconductor and the like to a circuit wiring through low melting point solder. SOLUTION: A wiring board comprises a circuit wiring 2 having a main conductive layer 5 comprising gold formed on the surface formed on an insulation substrate 1 by means of a thin film forming technology and on which an electronic component A is connected through solder material. A 10 to 1500- nm-thick barrier layer 6 comprising platinum or rhodium is formed covering at least a region of the circuit wiring 2 to which the electronic component A is connected through the solder material 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board, and more particularly to a wiring board used for a hybrid integrated circuit device, a semiconductor element housing package for housing a semiconductor element, and the like.

[0002]

2. Description of the Related Art Conventionally, a hybrid integrated circuit device having a large number of active components such as a semiconductor device, a large number of passive components such as a capacitance device and a resistor, and constituting a predetermined electronic circuit is usually made of aluminum oxide. A wiring board having a structure in which circuit wiring made of a refractory metal material such as tungsten or molybdenum is formed inside and on the surface of an insulating substrate made of a porous sintered body, and a semiconductor element or a capacitor element is provided on the upper surface of the insulating substrate of the wiring substrate. , A resistor and the like are mounted, and the electrodes of the semiconductor element and the like are electrically connected to the circuit wiring.

[0003] Wiring used in such conventional hybrid integrated circuit devices and the like is generally manufactured by employing a ceramic laminating technique and a thick film forming technique such as screen printing. Specifically, the following method is used. Produced by

[0004] (1) First, an organic solvent and a solvent are added to a ceramic raw material powder composed of aluminum oxide (Al ₂ O ₃ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO), calcium oxide (CaO) and the like. The mixture is mixed to form a slurry, and then formed into a sheet by a conventionally known doctor blade method, calender roll method, or the like to obtain a plurality of ceramic green sheets (ceramic green sheets). Then, a punching method and a punching method are applied to each ceramic green sheet to form a through hole at a predetermined position and to process the ceramic green sheet into a predetermined shape.

(2) Next, a metal paste obtained by adding and mixing an organic solvent and a solvent to tungsten or molybdenum powder is printed and applied in a predetermined pattern on the surface of the ceramic green sheet and in the through holes by a screen printing method. .

(3) Finally, the ceramic green sheets on which the metal paste is applied by printing are stacked one on top of the other and fired at a temperature of about 1600 ° C. in a reducing atmosphere, whereby the ceramic green sheets and the metal paste are sintered integrally. This completes a wiring board in which a circuit board of a predetermined pattern is formed inside and on the surface of the insulating base. However, in this conventional wiring board, the circuit board is entirely formed by screen-printing a metal paste, and it is difficult to form the circuit wiring by screen printing, and it is difficult to form the circuit wiring at a high density. Had the drawback that it could not be done.

In order to solve the above-mentioned drawbacks, there has been proposed a wiring board in which circuit wiring is formed by using a thin film forming technique capable of miniaturization instead of a conventional thick film forming technique such as screen printing.

[0008] A circuit board in which such circuit wiring is formed by a thin film forming technique is composed of an insulating layer made of an electrically insulating material such as an aluminum oxide sintered body, and an adhesive layer made of, for example, titanium and a gold made of gold. The main conductor layer is formed by a thin film forming technique such as an ion plating method, a sputtering method, and an evaporation method, and thereafter, these layers are processed into a predetermined pattern by using a photolithography technique to form a circuit wiring. It is formed by.

The adhesive layer made of titanium serves to firmly adhere the circuit wiring to the insulating base, and the main conductor layer made of gold serves as a propagation path for transmitting electric signals.

[0010]

However, in this wiring board, electrodes such as a semiconductor element, a capacitor element, and a resistor are connected to circuit wiring formed on the surface of the insulating base via a low melting point brazing material such as solder. When heat for melting the low melting point brazing material is applied to the circuit wiring, gold forming the main conductor layer of the circuit wiring diffuses into the low melting point brazing material to increase the melting point of the low melting point brazing material. As a result, the melting of the low melting point brazing material becomes incomplete, and the electrodes such as semiconductor elements, capacitance elements, and resistors are securely and firmly connected to the circuit wiring formed on the surface of the insulating base through the low melting point brazing material. It has a drawback that it cannot be electrically connected.

The present invention has been made in view of the above-mentioned drawbacks, and has as its object to form circuit wiring by a thin film forming technique,
While enabling high-density circuit wiring,
It is an object of the present invention to provide a wiring board for reliably and firmly electrically connecting electrodes of a semiconductor element, a capacitor element, a resistor, and the like to circuit wiring via a low melting point brazing material.

[0012]

According to the present invention, a circuit wiring is formed on an insulating substrate by a thin film forming technique and has a main conductor layer made of gold on a surface to which electronic components are joined via a brazing material. Wherein a barrier layer made of platinum or rhodium and having a thickness of 10 nm to 1500 nm is applied to at least a region of the circuit wiring to which an electronic component is joined via a brazing material. Things.

According to the wiring board of the present invention, since the circuit wiring is formed on the insulating base by the thin film forming technique, the circuit wiring can be miniaturized, and the circuit wiring can be formed at an extremely high density. .

In the wiring board of the present invention, at least a region made of platinum or rhodium and having a thickness of 10 nm to 1 nm is formed at least in a region of the circuit wiring where an electronic component is joined via a brazing material.
When a 500 nm barrier layer is formed and adhered, when connecting electrodes such as semiconductor elements, capacitors, resistors and the like to circuit wiring via low melting point brazing material such as solder, gold forming the main conductor layer of circuit wiring is used. Does not diffuse into the low melting point brazing material, and does not increase the melting point of the low melting point brazing material. As a result, the melting of the low melting point brazing material is completed, and the electrodes of semiconductor elements, capacitors, resistors, etc. In this way, it is possible to reliably and firmly make an electrical connection.

[0015]

Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of the wiring board of the present invention, wherein 1 is an insulating base, and 2 is a circuit wiring.

The insulating substrate 1 is made of an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body having an oxide film on its surface, a silicon carbide sintered body, a glass ceramic sintered body, sapphire, It is made of an electrically insulating material such as glass, quartz, or a silicon substrate. For example, when formed of an aluminum oxide-based sintered body, it is suitable for powdered materials such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. A ceramic green sheet (green ceramic sheet) is formed by adding a suitable organic solvent and a solvent to form a slurry and employing a conventionally known doctor blade method or calender roll method. The sheet is subjected to an appropriate punching process to obtain a predetermined shape and a high temperature (about 160
0 ° C.) or by mixing a raw material powder such as aluminum oxide with a suitable organic solvent and a solvent to prepare the raw material powder and form the raw material powder into a predetermined shape by a press molding machine. About 16
It is manufactured by firing at a temperature of 00 ° C.

A circuit wiring 2 is provided on the upper surface of the insulating base 1.
The circuit wiring 2 has, for example, a three-layer structure of an adhesive layer 3, an intermediate layer 4, and a main conductor layer 5.

The adhesive layer 3 of the circuit wiring 2 is made of titanium (T
i), chromium (Cr), nickel-chromium alloy (Ni-C
r), tantalum (Ta) or the like, and is deposited on the insulating substrate 1 by employing a thin film forming technique such as an evaporation method, an ion plating method, and a sputtering method.

The adhesive layer 3 has the function of increasing the bonding strength between the insulating substrate 1 and the circuit wiring 2 and has a thickness of 0.05 μm.
If it is less than m, it tends to be difficult to firmly join the circuit wiring 2 to the insulating base 1, and if it exceeds 0.5 μm, a large stress is generated when the adhesive layer 3 is formed by the thin film forming technique. At the same time, this is present inside, and the inherent stress tends to reduce the bonding strength between the insulating base 1 and the adhesive layer 3.

Therefore, the thickness of the adhesive layer 3 made of titanium or the like is preferably in the range of 0.05 μm to 0.5 μm, and more preferably in the range of 0.1 μm to 0.3 μm.

On the upper surface of the adhesive layer 3, an intermediate layer 4 is adhered. The intermediate layer 4 firmly joins the adhesive layer 3 and the main conductor layer 5 while simultaneously bonding the adhesive layer 3 and the main conductor layer 5 to each other. And acts to prevent mutual diffusion.

The intermediate layer 4 is made of platinum (Pt), palladium (Pd), titanium tungsten (Ti-W), nickel-chromium (Ni-Cr), or the like, and is formed by vapor deposition, ion plating, sputtering, or the like. It is applied on the upper surface of the adhesive layer 3 by a thin film forming technique.

If the thickness of the intermediate layer 4 is less than 0.05 μm, the interdiffusion between the adhesive layer 3 and the main conductor layer 5 tends to be unable to be effectively prevented.
If it exceeds m, the bonding strength between the adhesive layer 3 and the intermediate layer 4 tends to decrease due to the stress generated when the intermediate layer 4 is applied by the thin film forming technique. Therefore, the thickness of the intermediate layer 4 made of platinum, nickel-chromium, etc. is 0.05
The range is preferably from μm to 2.0 μm, and more preferably from 0.1 μm to 1.0 μm. Further, a main conductor layer 5 is applied on the upper surface of the intermediate layer 4 by a thin film forming technique such as a vapor deposition method, an ion plating method, and a sputtering method, and the main conductor layer 5 mainly functions as a passage for passing an electric signal. I do.

The main conductor layer 5 is made of gold (Au) having an extremely low conduction resistance, and if its thickness is less than 2.0 μm, the conduction resistance of the circuit wiring 2 is high, and it tends to be unsuitable as a wiring board. It is in. Therefore, it is preferable that the thickness of the main conductor layer 5 made of gold is 2.0 μm or more, and a range of 3.0 μm to 7.0 μm is also preferable in consideration of cost.

An adhesive layer 3 made of titanium or the like and an intermediate layer 4 made of platinum or nickel-chromium on the upper surface of the insulating base 1.
Wiring 2 having a three-layer structure of main conductor layer 5 made of gold and gold
In the wiring board provided with the circuit wiring 2, the adhesive layer 3, the intermediate layer 4, and the main conductor layer 5 forming the circuit wiring 2 are each formed by employing the thin film forming technique, so that the circuit wiring 2 is formed extremely finely. This makes it possible to form the circuit wirings 2 on the insulating base 1 with high density.

The circuit wiring 2 has an intermediate layer 4 made of platinum, nickel-chromium, or the like, which has good bonding properties between the adhesive layer 3 made of titanium or the like and the main conductor layer 5 made of gold. The bonding layer 3 and the main conductor layer 5 are firmly joined,
At the same time, when an electronic component A such as a semiconductor element, a capacitance element, and a resistor is connected to the circuit wiring 2 via a low melting point brazing material 7 such as solder, heat for melting the low melting point brazing material 7 is generated by the circuit wiring 2.
, And even if mutual diffusion between the adhesive layer 3 and the main conductor layer 5 is to occur, the mutual diffusion is effectively prevented by the intermediate layer 4, and the bonding of the circuit wiring 2 to the insulating base 1 is strengthened. You can do it.

Further, the circuit wiring 2 has a barrier layer 6 made of platinum (Pt) or rhodium (Rh) at least in a region where the electronic component A is joined via a brazing material on the surface thereof.
Are formed.

The barrier layer 6 is used to connect the electrodes of the electronic component A such as semiconductor elements, capacitors, resistors and the like to the circuit wiring 2 via a low melting point brazing material 7 such as solder. Is effectively diffused into the low-melting brazing material 7 to effectively prevent the melting point of the low-melting brazing material 7 from being increased, whereby the low-melting brazing material 7 has a predetermined low temperature. Thus, the electrodes of the electronic component A such as a semiconductor element, a capacitance element, and a resistor can be securely and firmly electrically connected to the circuit wiring 2.

The above platinum (Pt) or rhodium (Rh)
The barrier layer 6 has a thickness of 10 nm on the upper surface of the main conductor layer 3 by employing a conventionally known thin-film wiring technique such as an evaporation method, an ion plating method, and a sputtering method.
~ 1500 nm.

The barrier layer 6 has a thickness of 10 n.
When it is less than m, gold (Au) forming the main conductor layer 5 of the circuit line 2 when connecting the electrodes of the electronic component A such as a semiconductor element and a capacitor to the circuit wiring 2 via the low melting point brazing material 7 such as solder.
Cannot be effectively prevented from diffusing into the low melting point brazing material 7, and if it exceeds 1500 nm, a large intrinsic stress is generated when the barrier layer 6 is formed by the thin film forming technique, and the intrinsic stress is By being present inside the layer 6, the bonding strength with the main conductor layer 3 is reduced. Therefore,
The barrier layer 6 made of platinum or rhodium has a thickness of 1
It is limited to the range of 0 nm to 1500 nm.

Thus, according to the wiring board of the present invention, the electrodes of the electronic component A such as a semiconductor element, a capacitance element, and a resistor are provided on the circuit wiring 2 formed on the insulating base 1 with the low melting point brazing material 7 such as solder. To connect the electrodes of the electronic component A to the circuit wiring 2
The electronic component A is electrically connected to an external electric circuit if a part of the circuit wiring 2 is connected to an external electric circuit by electrically connecting the electronic component A to a semiconductor device or a hybrid integrated circuit device. .

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. Although the wiring circuit 2 is attached only to the upper surface of the insulating substrate 1, even if the wiring circuit 2 is provided only on the lower surface side of the insulating base 1,
It may be provided on both upper and lower main surfaces.

[0033]

According to the wiring board of the present invention, since the circuit wiring is formed on the insulating base by the thin film forming technique, the circuit wiring can be miniaturized, and the circuit wiring can be formed at an extremely high density. become.

In the wiring board of the present invention, at least a region made of platinum or rhodium having a thickness of 10 nm to 1 nm is formed at least in a region of the circuit wiring to which the electronic component is joined via the brazing material.
When a 500 nm barrier layer is formed and adhered, when connecting electrodes such as semiconductor elements, capacitors, resistors and the like to circuit wiring via low melting point brazing material such as solder, gold forming the main conductor layer of circuit wiring is used. Does not diffuse into the low melting point brazing material, and does not increase the melting point of the low melting point brazing material. As a result, the melting of the low melting point brazing material is completed, and the electrodes of semiconductor elements, capacitors, resistors, etc. In this way, it is possible to reliably and firmly make an electrical connection.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 2 ... Circuit wiring 3 ... Adhesive layer 4 ... Intermediate layer 5 ... Main conductor layer 6 ... Barrier layer 7 ... Low melting point brazing material A ... Electronics parts

Claims (1)

[Claims] 1. A wiring board formed on an insulating base by a thin film forming technique and having a circuit wiring having a main conductor layer made of gold on a surface to which an electronic component is joined via a brazing material, A wiring substrate, characterized in that a barrier layer made of platinum or rhodium and having a thickness of 10 nm to 1500 nm is formed on at least a region of a circuit wiring to which an electronic component is joined via a brazing material.