JPH11126849A - Package for containing semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To bond a bonding wire surely and firmly to a metallized wiring layer, in a short time. SOLUTION: This package for containing semiconductor element 3 hermetically comprises an insulating basic body 1 applied with a metallized wiring layer 4 for connecting respective electrodes of the semiconductor element 3 electrically via a bonding wire 5 and a cover body 2. At least the region of the metallized wiring layer 4 to be connected with bonding wire 5 is coated sequentially with a nickel layer 7 and a gold layer 8 having Knoop hardness of 160 or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device housing package for housing a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, a package for accommodating a semiconductor element for accommodating a semiconductor element is usually made of an aluminum oxide sintered body. An insulating base having a plurality of metallized wiring layers led out to an outer peripheral end; and an external base attached to the metallized wiring layer via a brazing material such as silver brazing in order to electrically connect the semiconductor element to an external electric circuit. The semiconductor device is composed of a lead terminal and a lid, and the semiconductor element is bonded and fixed to the bottom of the concave portion of the insulating base via an adhesive such as glass, resin, brazing material and the like, and each electrode of the semiconductor element is connected via a bonding wire. To the metallized wiring layer, and then a lid is bonded to the upper surface of the insulating base via a sealing material such as glass or resin, and the semiconductor is placed inside the container consisting of the insulating base and the lid. A semiconductor device as a final product by accommodating the element hermetically.

In such a conventional package for housing a semiconductor element, a nickel layer and a gold layer are sequentially deposited on the surface of a metallized wiring layer formed on an insulating substrate, and the metallized wiring layer is formed by the nickel layer and the gold layer. Oxidative corrosion is effectively prevented, and the bonding of the bonding wire to the metallized wiring layer is made strong.

[0004] Bonding of the bonding wire to the metallized wiring layer is generally performed by using an ultrasonic bonder. One end of the bonding wire is brought into contact with the upper part of the metallized wiring layer by sliding, so that the bonding wire and the gold layer are connected to each other. The bonding wire is bonded to the metallized wiring layer by generating frictional energy between the metallization wiring layer and causing the metal to diffuse between the bonding wire and the gold layer with the frictional energy.

[0005]

However, recently,
With the rapid progress of high density and high integration of semiconductor devices, the number of electrodes has become extremely large, from several hundred to several thousand, and the metallization of each electrode of the semiconductor device and the package for housing the semiconductor device has been increasing. This disadvantageously requires a long time to electrically connect the wiring layer to the wiring layer via a bonding wire.

In order to solve the above-mentioned drawbacks, the ultrasonic output of the ultrasonic bonder is increased, and the electrical connection between the electrode of the semiconductor element and the metallized wiring layer of the package for accommodating the semiconductor element via the bonding wire for a short time. Has been attempted. However, in the conventional package for housing a semiconductor element, the Knoop hardness of the nickel layer adhered to the surface of the metallized wiring layer is 120 or less,
When bonding a bonding wire to a metallized wiring layer using an ultrasonic bonder, a portion of the ultrasonic vibration is absorbed by the soft nickel layer and the frictional energy generated between the bonding wire and the gold layer is small. As a result, metal diffusion between the bonding wire and the gold layer becomes insufficient, and a disadvantage is induced that the bonding wire cannot be firmly bonded to the metallized wiring layer. The present invention has been devised in view of the above-mentioned drawbacks, and has as its object to bond a bonding wire to a metallized wiring layer firmly in a short period of time, and to securely and strongly electrically connect each electrode of a semiconductor element to a predetermined external electric circuit. An object of the present invention is to provide a semiconductor element housing package that can be connected.

[0007]

The present invention comprises an insulating base having a metallized wiring layer to which each electrode of a semiconductor element is electrically connected via a bond wire, and a lid.
A semiconductor element housing package for hermetically housing a semiconductor element therein, wherein at least a region of the metallized wiring layer to which a bonding wire is connected has a Knoop hardness of 1.
It is characterized in that 60 or more nickel layers and gold layers are sequentially applied.

According to the package for accommodating a semiconductor element of the present invention, the Knoop hardness of the nickel layer formed on the surface of the metallized wiring layer is 160 or more, and since it is hard, the bonding wire is formed using an ultrasonic bonder. When bonding the metal layer to the metallized wiring layer, part of the ultrasonic vibration is hardly absorbed by the nickel layer, and as a result, the friction energy generated between the bonding wire and the gold layer becomes extremely large, and the bonding time Even if the length is short, sufficient metal diffusion is performed between the bonding wire and the gold layer, so that the bonding wire can be securely and firmly bonded to a predetermined metallized wiring layer.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows an embodiment of a package for accommodating a semiconductor element according to the present invention, wherein 1 is an insulating base, and 2 is a lid. The insulating base 1 and the lid 2 constitute a container for housing the semiconductor element 3.

The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, etc. A recess 1a forming a space for accommodating the element 3 is provided, and the semiconductor element 3 is bonded and fixed to the bottom of the recess 1a via an adhesive such as glass, resin, brazing material or the like.

When the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, aluminum oxide (Al ₂ O)
₃ ), silicon oxide (SiO ₂ ), calcium oxide (Ca
O), magnesium oxide (MgO) and other ceramic raw material powders are mixed with an appropriate organic solvent and solvent to form a slurry, which is formed into a sheet by using a conventionally known doctor blade method or calender roll method. A ceramic green sheet (ceramic green sheet) is obtained by the above method. Thereafter, the ceramic green sheet is subjected to an appropriate punching process and a plurality of sheets are laminated, and a high temperature (about 1
(600 ° C.).

A plurality of metallized wiring layers 4 are attached to the insulating base 1 from the periphery of the concave portion 1a to the outer peripheral edge, and each electrode of the semiconductor element 3 is bonded around the concave portion 1a of the metallized wiring layer 4. External lead terminals 6 are electrically connected to each other through wires 5 and are led to the outer peripheral ends, and are brazed through brazing materials such as silver brazing.

The metallized wiring layer 4 is made of tungsten,
A metal paste made of a high melting point metal powder such as molybdenum and manganese, and a suitable organic solvent and a solvent added to and mixed with the high melting point metal powder such as tungsten is applied to a ceramic green sheet serving as an insulating substrate 1 in a well-known manner. By printing and applying a predetermined pattern by a screen printing method, the insulating substrate 1 is formed from the periphery of the concave portion 1a to the outer peripheral edge.

On the exposed surface of the metallized wiring layer 4, a nickel layer 7 and a gold layer 8 having a Knoop hardness of 160 or more are sequentially applied.

The nickel layer 7 functions as a base metal layer for depositing the gold layer 8 on the metallized wiring layer 4. For example, by adopting an electroless plating method, the metallized wiring layer 4 Is immersed in an electroless plating bath composed of 30 g / l of nickel sulfate, 10 g / l of sodium phosphite, and 10 g / l of sodium acetate, and nickel containing phosphorus is formed on the surface of the metallized wiring layer 4. By being deposited, it is formed on the surface of the metallized wiring layer 4.

The nickel layer 7 has a Knoop hardness of 160 or more and is so hard that when the bonding wire 5 is bonded to the metallized wiring layer 4 using an ultrasonic bonder, the nickel layer 7 It hardly absorbs a part of the vibration, and as a result, a large frictional energy is generated between the bonding wire 5 and the gold layer 8,
Due to the large frictional energy, even if the bonding time is short, sufficient metal diffusion is performed between the bonding wire 5 and the gold layer 8, whereby the bonding wire 5 is securely and firmly bonded to the metallized wiring layer 4. be able to.

When the Knoop hardness of the nickel layer 7 becomes less than 160, the bonding wire 5 is bonded to the metallized wiring layer 4 using an ultrasonic bonder.
The nickel layer 7 absorbs a part of the ultrasonic vibration, and no large frictional energy is generated between the bonding wire 5 and the gold layer 8, so that the bonding wire 5 is firmly bonded to the metallized wiring layer 4 in a short time. Can not be done.
Accordingly, the Knoop hardness of the nickel layer 7 is specified to be 160 or more.

The Knoop hardness of the nickel layer 7 is 16
In order to make it 0 or more, after nickel containing phosphorus is applied to the surface of the metallized wiring layer 4 by an electroless plating method,
It is obtained by applying a temperature of about 600 ° C. for about 30 minutes to 2 hours and performing heat treatment.

The nickel layer 7 has a thickness of 0.5
When the thickness is less than μm, it is difficult to firmly join the gold layer 8 to the metallized wiring layer 4, and as a result, there is a risk that the bonding wire 5 cannot be firmly joined to the metallized wiring layer 4. When the thickness exceeds 0.0 μm, when the nickel layer 7 is applied to the metallized wiring layer 4 by plating or the like, a large stress is present inside the nickel layer 7 and the nickel layer 7 is peeled off from the metallized wiring layer 4 even when a small external force is applied. There is a risk of doing it.
Therefore, the nickel layer 7 has a thickness of 0.5 to 1
It is preferable that the thickness be in the range of 5.0 μm.

The nickel layer 7 has a gold layer 8 adhered to the surface thereof. A bonding wire 5 is bonded to the gold layer 8 by metal diffusion, whereby the bonding wire 5 is connected to the metallized wiring layer 4. It will be electrically connected.

The gold layer 8 is formed by a plating method.
Specifically, 8 g / L of potassium potassium cyanide, 30 g / L of potassium cyanide, 30 g / L of potassium hydrogen phosphate, 15 g / L of potassium acetate /
Nickel layer in a galvanic bath
Dipped metallized metal layer 4 covered with
A predetermined electric field required for electrolytic plating is applied to the metallized metal layer 4 to deposit gold on the surface of the nickel layer 7, thereby forming the metallized metal layer 4 on the surface of the nickel layer 7.

The thickness of the gold layer 7 is 0.5 μm.
If it is less than 0.5 mm, the bonding amount of the bonding wire 5 may be reduced to 0.5 μm or more because there is a risk that the absolute amount of metal diffusion is reduced and the bonding strength of the bonding wire 5 is reduced when bonding the bonding wire 5 by metal diffusion. In consideration of the properties, it is preferable to set the thickness in the range of 0.5 μm to 3.0 μm.

On the other hand, the external lead terminals 6 brazed to the metallized wiring layer 4 serve to connect the semiconductor element 3 housed therein to an external electric circuit, and connect the external lead terminals 6 to the external electric circuit. As a result, the semiconductor element 3 housed inside is electrically connected to an external electric circuit via the bonding wire 5, the metallized wiring layer 4, and the external lead terminal 6.

The external lead terminal 6 is made of a metal material such as an iron-nickel-cobalt alloy or an iron-nickel alloy.
For example, it is formed into a predetermined shape by subjecting an ingot such as an iron-nickel-cobalt alloy to a conventionally known metal working method such as a rolling method or a punching method.

Further, the external lead terminal 6 may be formed by plating a metal having good conductivity and excellent corrosion resistance made of nickel, gold or the like to a thickness of 1 to 20 μm on its surface by plating. The oxidation corrosion of the terminal 6 can be effectively prevented, and the electrical connection between the external lead terminal 6 and the external electric circuit can be made good. Therefore, external lead terminals 6
It is preferable that nickel, gold or the like is adhered to the surface of the metal to a thickness of 1 to 20 μm.

Thus, according to the package for accommodating a semiconductor element of the present invention, the semiconductor element 3 is bonded and fixed to the bottom surface of the concave portion 1a of the insulating base 1 via an adhesive such as glass, resin or brazing material. The electrodes are electrically connected to the metallized wiring layer 4 via bonding wires 5, and then the lid 2 is joined to the upper surface of the insulating base 1 with a sealing material such as glass or resin. The semiconductor device 3 as a final product is obtained by hermetically housing the semiconductor element 3 in the container formed of the semiconductor device 3.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. Knoop hardness of 160 on all exposed surfaces
Although the nickel layer 7 is applied as described above, the nickel layer 7 may be applied only to the metallized wiring layer 4 in the vicinity of the concave portion 1a of the insulating base 1, that is, only in the region where the bonding wire 5 is bonded.

[0028]

According to the package for housing a semiconductor element of the present invention, the Knoop hardness of the nickel layer formed on the surface of the metallized wiring layer is 160 or more, and the nickel layer is hard. When bonding the bonding wire to the metallized wiring layer, part of the ultrasonic vibration is hardly absorbed by the nickel layer, and as a result, the friction energy generated between the bonding wire and the gold layer becomes extremely large, Even if the bonding time is short, sufficient metal diffusion is performed between the bonding wire and the gold layer, whereby the bonding wire can be securely and firmly bonded to a predetermined metallized wiring layer.

Therefore, in the package for accommodating a semiconductor element of the present invention, each electrode of the semiconductor element can be reliably electrically connected to an external electric circuit.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a semiconductor element storage package according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 2 ... Lid 4 ... Metallized wiring layer 5 ... Bonding wire 7 ... Nickel layer 8 ... Gold layer

Claims (2)

[Claims] 1. A semiconductor element housing package comprising an insulating base having a metallized wiring layer electrically connected to each electrode of a semiconductor element via a bonding wire and a lid, wherein the semiconductor element is hermetically housed therein. A semiconductor element storage package, wherein a nickel layer and a gold layer having a Knoop hardness of 160 or more are sequentially applied to at least a region of the metallized wiring layer to which a bonding wire is connected. 2. The method according to claim 1, wherein said nickel layer has a thickness of 0.5 μm to 1 μm.
2. The package for accommodating a semiconductor element according to claim 1, wherein the thickness is 5.0 μm.