JPH08335777A - Multilayer thin film wiring board - Google Patents

Abstract

PURPOSE: To provide a multilayer thin film wiring board in which the outer lead terminals are secured rigidly to an insulating board while preventing the delamination of an insulating film from the insulating board or the fluctuation of characteristics by fusion and each electronic device, connected with the circuit wiring film, can be electrically connected reliably and rigidly with other external electric circuit board through outer lead terminals. CONSTITUTION: An insulating film 3 of organic high polymer material and a circuit wiring film 2 of metal material are laminated alternately in multilayer on an insulating board 1 having a metallization layer 4 by thin film preparation technology. The metallization layer 4 is connected electrically with the circuit wiring film 2 and bonded with outer lead terminals 5 by ultrasonic bonding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer thin film wiring board used in a hybrid integrated circuit device, a package for accommodating semiconductor elements, and the like.

[0002]

2. Description of the Related Art Conventionally, a wiring board used for a hybrid integrated circuit device, a package for accommodating a semiconductor element, or the like has its circuit wiring formed by a thick film forming technique such as a Mo--Mn method.

In the Mo-Mn method, an organic solvent and a solvent are added to a metal powder made of a refractory metal such as tungsten, molybdenum, and manganese to form a paste-like metal paste on the outer surface of a green or sintered ceramic body. In this method, a predetermined pattern as a circuit wiring is printed and applied by a screen printing method, and then this is baked in a reducing atmosphere to sinter and integrate the high melting point metal powder and the ceramic body.

[0004]

However, this M
When the circuit wiring is formed by using the o-Mn method, it is difficult to miniaturize the circuit wiring because the circuit wiring is formed by screen-printing a metal paste, and the circuit wiring cannot be densified. Had.

Therefore, in order to solve the above-mentioned drawbacks, instead of forming the circuit wiring by the conventional thick film forming technique, a multilayer thin film wiring substrate formed by using a thin film forming technique capable of miniaturization is used. It's coming.

The multilayer thin film wiring substrate formed with this circuit wiring by the thin film forming technique is usually an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, or a glass ceramic. It consists of a sintered body, etc., and tungsten, molybdenum,
A circuit wiring film made of aluminum, copper, chromium, nickel, etc. and an insulating film made of an organic polymer material such as polyimide are alternately applied in multiple layers on an insulating substrate on which a metallized wiring layer made of manganese or the like is applied. A structure in which a part of the circuit wiring film is electrically connected to the metallized wiring layer and external lead terminals are attached to the metallized wiring layer led out to the lower surface of the insulating substrate through a silver brazing material (silver-copper alloy). By connecting electrodes such as semiconductor elements and capacitors via solder to the circuit wiring film, each electronic component such as semiconductor elements and capacitors is electrically connected to each other through the circuit wiring film. If the external lead terminal is connected to another external electric circuit board, each electronic component connected to the circuit wiring film will pass through the circuit wiring film, the metallized wiring layer and the external lead terminal. It is adapted to be electrically connected to the part an electrical circuit board. Incidentally, the multilayer thin film wiring board, after the circuit wiring film made of aluminum, copper, chromium, nickel or the like and the insulating film made of an organic polymer material such as polyimide are alternately laminated on the upper surface of the insulating substrate, External lead terminals are attached to the metallized wiring layer leading out to the lower surface of the insulating substrate. This is an etching process that is used to deposit a circuit wiring film in a predetermined pattern on an insulating substrate.
This is to prevent unnecessary etching of the external lead terminals attached to the lower surface of the insulating substrate by the etching solution during the etching process.

However, in the above-mentioned multilayer thin film wiring board, the heat resistance of the organic polymer material such as polyimide for forming the insulating film is poor, and there is a large difference between the thermal expansion coefficient of the insulating substrate and the thermal expansion coefficient of the insulating film. Therefore, when the external lead terminals are attached to the lower surface of the insulating substrate in which the circuit wiring film and the insulating film are alternately laminated on the upper surface through the silver solder material (silver-copper alloy), the silver solder is used. When heat for heating and melting the material is applied to both the insulating film and the insulating substrate, the insulating film peels off from the insulating substrate, or the insulating film melts to change the characteristics, resulting in a multilayer structure. The defect that the function as a thin film wiring board is lost is induced.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to firmly prevent external lead terminals on an insulating substrate while effectively preventing characteristic changes due to peeling or melting of the insulating film from the insulating substrate. An object of the present invention is to provide a multilayer thin-film wiring board that can be securely attached to each external electronic circuit board that is attached and connected to a circuit wiring film to another external electric circuit board through external lead terminals.

[0009]

A multilayer thin film wiring substrate of the present invention comprises an insulating substrate having a metallized wiring layer, and an insulating film made of an organic polymer material and a circuit wiring film made of a metal material are alternately formed on the insulating substrate by a thin film forming technique. It is laminated in multiple layers, and the circuit wiring film is electrically connected to the metallized wiring layer, and external lead terminals are bonded by ultrasonic bonding.

[0010]

According to the multilayer thin film wiring board of the present invention, since the circuit wiring film is formed by the thin film forming technique, the circuit wiring film can be miniaturized and the circuit wiring film can be made high in density.

According to the multilayer thin film wiring board of the present invention,
Since the external lead terminals are joined by ultrasonic bonding to the metallized wiring layer adhered to the insulating substrate, unnecessary heat is not applied to the insulating substrate and the insulating film when attaching the external lead terminals, As a result, the insulating film is firmly adhered to the insulating substrate without changing the characteristics, and each electronic component connected to the circuit wiring film is securely and firmly electrically connected to another external electric circuit board via the external lead terminals. Can be connected.

[0012]

The present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a multilayer thin film wiring board according to the present invention, wherein 1 is an insulating substrate, 2 is a circuit wiring film, and 3 is an insulating film.

The insulating substrate 1 is made of an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, a glass ceramic sintered body, or the like. When it is composed of an aluminum oxide sintered body, alumina, silica, magnesia, calcia, etc. are mixed with a suitable organic solvent and a solvent to form a sludge and a doctor blade method or calender roll method is used. To form a ceramic green sheet (ceramic green sheet), and then subject the ceramic green sheet to an appropriate punching process to form a predetermined shape and a high temperature (about 1600).
It is manufactured by firing at (° C).

On the upper surface of the insulating substrate 1, a multi-layer wiring portion A in which circuit wiring films 2 and insulating films 3 are alternately arranged in multiple layers is adhered, and the insulating substrate 1 supports the multi-layer wiring portion A. Acts as a support member.

A metallized wiring layer 4 extending from the upper surface to the lower surface of the insulating substrate 1 is adhered and formed, and the metallized metal layer 4 covers the circuit wiring film 2 adhered to the upper surface of the insulating substrate 1. It serves to electrically connect to external lead terminals 5 attached to the lower surface of the insulating substrate 1 described later.

The metallized wiring layer 4 is made of tungsten,
A method of forming a hole in the upper and lower surfaces of the ceramic green sheet and the ceramic green sheet which will be the insulating substrate 1 and is made of a metal material such as molybdenum or manganese, and a metal paste obtained by adding and mixing an appropriate organic solvent or solvent to the metal material. A predetermined pattern is printed and filled in the through hole formed by applying a known pattern by a screen printing method or the like, so that the insulating substrate 1 is adhered and formed from the upper surface to the lower surface.

The insulating substrate 1 to which the metallized wiring layer 4 has been applied further has circuit wiring films 2 and insulating films 3 alternately and multilayerly deposited on the upper surface thereof. Thus, the multi-layer wiring part A is formed.

The circuit wiring film 2 of the multi-layer wiring portion A is made of a metal material such as aluminum, copper, chromium, nickel or the like, and is insulated by employing a thin film forming technique such as a vapor deposition method or a sputtering method and an etching processing technique. A plurality of layers are formed on the substrate 1 with the insulating film 3 interposed therebetween.
In this case, since the circuit wiring film 2 is formed by the thin film forming technique, the circuit wiring film 2 can be miniaturized and the circuit wiring film 2 can be formed with high density.

A part of the circuit wiring film 2 is an insulating substrate 1.
If the electronic components such as the semiconductor element 6 and the capacitor 7 are connected to the circuit wiring film 2 through solder, the semiconductor element 6 and the capacitor 7 are in contact with the metallized wiring layer 4 attached to the semiconductor element 6 and the capacitor 7.
The electronic components such as the above are electrically connected to each other through the circuit wiring film 2 and also electrically connected to a predetermined metallized wiring layer 4.

The circuit wiring film 2 has a thickness of 0.0.
If it is less than 5 μm, the electric resistance of the circuit wiring film 2 tends to be large, and at the same time, pinholes and disconnections tend to occur in the circuit wiring film 2, and if it exceeds 30 μm, the circuit wiring film 2 is formed into a thin film. The range of 0.05 μm to 20 μm is preferable because the circuit wiring film 2 tends to peel off from the insulating film 3 due to internal stress when formed by the technique and the fine processing of the circuit wiring film 2 tends to be difficult. Suitably 1 μm to 5 μm thick, optimally 2 μm
It is preferable to set the thickness to m to 3 μm.

An insulating film 3 is disposed between the circuit wiring films 2, and the insulating film 3 serves to maintain the electrical insulation of the circuit wiring films 2 located above and below.

The insulating film 3 is made of an organic polymer material such as polyimide resin. For example, 50 mol% of 4,4'-diaminodiphenyl ether and 5% of diaminodiphenyl sulfone.
A polymer solution consisting of 0 mol% of 3,3′-biphenyltetracarboxylic dianhydride was applied on the insulating substrate 1 by spin coating, and then heat of about 400 ° C. was applied to heat the polymer solution. By being cross-linked, it is deposited between the circuit wiring films 2 on the insulating substrate 1.

If the thickness of the insulating film 3 is less than 1 μm, pinholes are likely to be generated in the insulating film 3, and the electrical insulation between the circuit wiring films 2 formed above and below the insulating film 3 is facilitated. It tends to be difficult to achieve, and 50μ
If it exceeds m, it tends to be difficult to accurately form a via hole in the insulating film 3 that serves as a conductive path for electrically connecting the circuit wiring films 2 formed above and below with the insulating film 3 interposed therebetween. Therefore, the range of 1 μm to 50 μm is good,
Suitable thickness is 2 to 10 μm, optimally 3 μm
It is preferable to set the thickness to 5 μm.

Further, the insulating substrate 1 having the multi-layer wiring portion A adhered on the upper surface has external lead terminals 5 arranged on the lower surface thereof, and the external lead terminals 5 are metallized wirings led to the lower surface of the insulating substrate 1. It is bonded to the layer 4 by ultrasonic bonding.

The external lead terminals 5 have a function of connecting electronic components such as the semiconductor element 6 and the capacitor 7 connected to the multilayer wiring portion A to another external electric circuit board, and are made of iron-nickel-cobalt alloy or iron. -Metal material such as nickel alloy or copper. For example, ingot (lump) of iron-nickel-cobalt alloy is subjected to well-known metal processing such as rolling method or punching method to obtain a predetermined shape. Is formed.

The external lead terminals 5 are bonded to the metallized wiring layer 4 extending to the lower surface of the insulating substrate 1 by ultrasonic bonding. Specifically, the external lead terminals are connected to the metallized wiring layer 4 extending to the lower surface of the insulating substrate 1. 5 is brought into contact with the external lead terminal 5 and the ultrasonic oscillating horn 1.
While pressing with a pressure of 5 to 6.5 Kgf / mm ² , ultrasonic vibration having a frequency of 30 to 50 KHz and an amplitude of 10 to 30 μm was applied for 0.01 to 0.2 seconds to connect the metallized wiring layer 4 and the external lead terminals 5 to each other. It is carried out by causing solid-phase bonding by mutual diffusion between the two.

The attachment of the external lead terminal 5 to the metallized wiring layer 4 is solid phase bonding by mutual diffusion of the metallized wiring layer 4 and the external lead terminal 5, and the bonding interface between the external lead terminal 5 and the metallized wiring layer 4 is Since the two are integrated, the bonding strength is extremely strong.
Even if an external force is applied to the external lead terminals 5, the external lead terminals 5 are not easily separated from the metallized wiring layer 4 by the external force.

Further, since the external lead terminals 5 are bonded to the metallized wiring layer 4 by ultrasonic bonding, unnecessary high temperature heat is not applied to the insulating substrate 1 and the multilayer wiring portion A, and as a result, insulation is achieved. The film 3 is not peeled off from the insulating substrate 1 or the insulating film 3 is melted so that the characteristics are not changed, and the insulating film 3 is firmly adhered to the insulating substrate 1 without changing the characteristics. Each electronic component connected to the wiring film 2 can be securely and firmly electrically connected to another external electric circuit board via the external lead terminal 5.

Thus, according to the above-mentioned multilayer thin-film wiring board, electronic components such as the semiconductor element 6 and the capacitor 7 are connected to the circuit wiring film 2 of the multilayer wiring portion A adhered to the upper surface of the insulating substrate 1 via solder. Then, the electronic components such as the semiconductor element 6 and the capacitor 7 are electrically connected to each other through the circuit wiring film 2, and if the external lead terminal 5 is connected to another external electric circuit board, the semiconductor element 6 and the capacitor 7 are connected. The electronic components such as are electrically connected to the external electric circuit board through the external lead terminals 5.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described embodiments, the metallized wiring layer 4 can be formed. If a nickel layer having a thickness of 1 μm to 10 μm is deposited on the exposed surface, the metallized wiring layer 4
The oxidative corrosion is effectively prevented, and the connection between the metallized wiring layer 4 and the circuit wiring film 2 and the connection between the metallized wiring layer 4 and the external lead terminal 5 are strengthened. Therefore,
It is preferable that a nickel layer is deposited on the exposed surface of the metallized wiring layer 4 to a thickness of 1 μm to 10 μm.

Further, nickel on the surface of the external lead terminal 5,
It is possible to effectively prevent oxidative corrosion of the external lead terminals 5 by depositing a metal having excellent corrosion resistance such as gold and having good wettability with the brazing material to a thickness of 0.1 to 20 μm by a plating method. In addition, the connection between the external lead terminal 5 and the external electric circuit board can be made good. Therefore, the external lead terminal 5 has nickel, gold, etc. on its surface.
It is preferable to deposit them in a thickness of 1 μm to 20 μm.

Further, in the above embodiment, the metallized wiring layer 4
The external lead terminal 5 was directly bonded to the external ultrasonic wave by ultrasonic bonding. A silver-copper alloy was placed between the metallized wiring layer 4 and the external lead terminal 5, and the metallized wiring layer 4 was formed on the silver-copper alloy.
Alternatively, the external lead terminals 5 may be attached to the metallized wiring layer 4 by bonding each of the external lead terminals 5 by ultrasonic bonding.

[0033]

According to the multilayer thin film wiring board of the present invention, since the circuit wiring film is formed by the thin film forming technique, the circuit wiring film can be miniaturized and the circuit wiring film can be made high in density.

According to the multilayer thin film wiring board of the present invention,
Since the external lead terminals are joined by ultrasonic bonding to the metallized wiring layer adhered to the insulating substrate, unnecessary heat is not applied to the insulating substrate and the insulating film when attaching the external lead terminals, As a result, the insulating film is firmly adhered to the insulating substrate without changing the characteristics, and each electronic component connected to the circuit wiring film is securely and firmly electrically connected to another external electric circuit board via the external lead terminals. Can be connected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a multilayer thin film wiring board of the present invention.

[Explanation of symbols]

 1 ... Insulating substrate 2 ... Circuit wiring film 3 ... Insulating film 4 ... Metallized wiring layer 5 ... External lead terminal A. ... Multi-layer wiring

Claims (1)

[Claims] 1. An insulating substrate having a metallized wiring layer, wherein an insulating film made of an organic polymer material and a circuit wiring film made of a metal material are alternately laminated in multiple layers by a thin film forming technique.
A multilayer thin-film wiring board, characterized in that the circuit wiring film is electrically connected to the metallized wiring layer and external lead terminals are bonded by ultrasonic bonding.