JP3488838B2 - Package for storing semiconductor elements - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a semiconductor element accommodating package for accommodating a semiconductor element is generally made of an electrically insulating material such as an aluminum oxide sintered body, and has a recessed portion for accommodating the semiconductor element in a substantially central portion of its upper surface. And an insulating substrate having a wiring layer made of a refractory metal powder such as tungsten, molybdenum, or manganese led out from the periphery of the recess to the outer peripheral edge, and the wiring layer for electrically connecting the semiconductor element to an external electric circuit. An external lead terminal made of an iron-nickel-cobalt alloy (54% by weight Fe-29% by weight Ni-17% by weight Co) attached via a silver solder, and a lid body. The semiconductor element is adhered and fixed to the bottom surface of the recess through an adhesive such as glass, resin, or brazing material, and each electrode of the semiconductor element is electrically connected to the wiring layer through a bonding wire. Continued, and thereafter brazing material the lid on insulating base top surface, glass, are joined by a sealing material such as a resin, a semiconductor device by sealing a semiconductor element hermetically in the interior.

In such a semiconductor device, an external lead terminal is connected to a wiring conductor of an external electric circuit board through a conductive bonding material such as solder, whereby each electrode of the semiconductor element is electrically connected to the external electric circuit. It will be.

In addition, in order to improve the electrical connection between the external lead terminals and the external electric circuit, and to effectively prevent the external lead terminals from being oxidized and corroded, the semiconductor element housing package is usually The outer surface of the external lead terminal is coated with nickel and, if necessary, gold by electrolytic plating or the like.

[0005]

However, in this conventional package for accommodating semiconductor elements, the external lead terminals have an iron-nickel-cobalt alloy (54 wt% Fe-29 wt% N).
i-17 wt% Co) with a Young's modulus of 1400
0kgf ^/ mm ² ~15000kgf ^/ mm 2 and higher it is inferior in flexibility, plating layer of nickel is deposited on the outer surface of the external lead terminals particle size of about 0.3
Since it is as small as 1 μm and the number of crystal grain boundaries is extremely large, dislocation (boundary line between a region where slippage is caused by an external force of nickel atoms constituting each crystal and a region where no slippage is caused) is poor, and it is hard and brittle. When the external lead terminal vibrates violently around the brazing part as a fulcrum due to strong vibration applied to the semiconductor element storage package because it is difficult to deform, etc., the stress accompanying this vibration causes cracks in the hard and brittle nickel plating layer first, and then There is a drawback that stress concentrates on the crack portion and breaks in the nickel plating layer, and finally stress concentrates on the external lead terminal of the base of the crack portion and breaks the external lead terminal. .

The present invention has been devised in view of the above-mentioned drawbacks, and an object thereof is to prevent the external lead terminals from being broken even when severe vibration is applied, and to keep the semiconductor element housed inside for a long period of time. It is an object of the present invention to provide a package for accommodating a semiconductor element that can be securely and firmly electrically connected to a predetermined external electric circuit.

[0007]

According to the present invention, a wiring layer to which electrodes of the semiconductor element are connected is attached to the outer surface of an insulating container having a cavity for accommodating the semiconductor element therein, and the wiring is also provided. A package for accommodating a semiconductor device, which is obtained by brazing external lead terminals to a layer, wherein the external lead terminals have a Young's modulus of 7,000 kgf / mm ^{2 to} 1300.
An electric resistance of 0 kgf / mm ² or less, 50 μΩ · cm or less, and an outer surface coated with a plating layer made of nickel and a plating layer made of gold having a grain size of 2 μm to 5 μm. Is.

Further, the present invention is characterized in that the plating layer made of nickel has a thickness of 1 μm to 10 μm.

According to the semiconductor element housing package of the present invention, the Young's modulus of the external lead terminal is 7,000 kgf / m.
It has a low m ^{2 to} 13000 kgf / mm ^{2 and} is highly flexible, and the nickel plating layer deposited on the outer surface of the external lead terminal has a large grain size of 2 μm to 5 μm, and dislocations can be easily moved and deformed. Since it is easy to perform, severe vibration is applied to the package for housing the semiconductor element, the external lead terminal vibrates violently around the brazing part as a fulcrum, and even if the stress due to the vibration acts on the external lead terminal, the stress is The lead terminals and the nickel plating layer are appropriately deformed to be absorbed, and as a result, the external lead terminals are effectively prevented from breaking, and the semiconductor element accommodated inside through the external lead terminals can be effectively protected from external damage. It is possible to make reliable and strong electrical connection to an electric circuit.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention will now be described in detail with reference to the accompanying drawings. 1 and 2 show an embodiment of a package for housing a semiconductor device of the present invention, in which 1 is an insulating base and 2 is a lid. The insulating base 1 and the lid 2 constitute an insulating container 4 for housing the semiconductor element 3.

The insulating substrate 1 has a semiconductor element 3 on its upper surface.
Is provided with a concave portion 1a forming a void for accommodating a semiconductor element 3 on the bottom surface of the concave portion 1a.
It is adhered and fixed through an adhesive material such as a brazing material.

The insulating substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, an aluminum nitride sintered body, or a mullite sintered body. , Aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, etc. are mixed with an appropriate organic binder, solvent, etc. to make a sludge, and the sludge is formed into a sheet by a doctor blade method or a calendar roll method. Produced by molding to obtain a ceramic green sheet (ceramic green sheet), and then subjecting the ceramic green sheet to appropriate punching and punching, laminating a plurality of these, and firing at a high temperature of about 1600 ° C. To be done.

Further, a plurality of wiring layers 5 are formed on the insulating substrate 1 from the periphery of the recess 1a to the outer peripheral edge portion, and the semiconductor element 3 is formed in the peripheral region of the recess 1a of the wiring layer 5. Each electrode is electrically connected via a bonding wire 6, and an external lead terminal 7 connected to an external electric circuit is provided in a region extending to the outer peripheral end of the insulating substrate 1 via a brazing material such as silver solder. It is attached by brazing.

The wiring layer 5 acts as a conductive path when connecting the electrodes of the semiconductor element 3 to an external electric circuit, and is made of a metal material such as tungsten, molybdenum, or manganese.

The wiring layer 5 is made of, for example, tungsten,
A metal paste obtained by adding and mixing an appropriate organic solvent or solvent to a refractory metal powder such as molybdenum or manganese is printed in advance in a predetermined pattern on the surface of the ceramic green sheet to be the insulating substrate 1 by a conventionally known screen printing method or the like. When the ceramic green sheet is applied and fired to form the insulating substrate 1, the insulating substrate 1 is simultaneously formed in a predetermined pattern from the periphery of the concave portion 1a to the outer peripheral end.

It is to be noted that the wiring layer 5 is formed by depositing a metal such as nickel or gold having a high corrosion resistance and a good wettability with a brazing material to a thickness of 1 to 20 μm by a plating method. The oxidative corrosion of the wiring layer 5 can be effectively prevented and the bonding wire 6 to the wiring layer 5 can be effectively prevented.
Connection and brazing of the external lead terminal 7 can be made firm. Therefore, it is preferable that the exposed surface of the wiring layer 5 is coated with a metal such as nickel or gold having a high corrosion resistance and a good wettability with the brazing material to a thickness of 1 μm to 20 μm by a plating method.

External lead terminals 7 are brazed to the wiring layer 5, and the external lead terminals 7 are connected to an external electric circuit via solder or the like, whereby the electrodes of the semiconductor element 3 are bonded. It will be connected to an external electric circuit via the wire 6 and the wiring layer 5.

The external lead terminal 7 has a Young's modulus of 700.
0 kgf / mm ² to 13000kgf / mm ² of a metallic material, in particular iron - nickel - 800 cobalt alloy
One that is heat-treated and softened at a temperature of ℃ or more, preferably about 900 ° C. is suitably used, and the external lead terminal 7 is placed on the wiring layer 5 with a brazing material such as silver brazing interposed therebetween. Then, heat of about 800 ° C. to 850 ° C. is applied to the brazing material,
It is attached to the wiring layer 5 by melting the brazing material.

The Young's modulus of the external lead terminal 7 is 7
Since it is highly flexible at 000 kgf / mm ^{2 to} 13000 kgf / mm ² , violent vibration is applied to the package for housing the semiconductor element, and the external lead terminals 7 vibrate violently with the brazing part as a fulcrum, and the stress associated with the vibration causes the external lead Even if it acts on the terminal 7, the stress is absorbed by the appropriate deformation of the outer lead end 7, and as a result,
The breakage of the external lead terminals 7 is effectively prevented, and the semiconductor element 3 housed inside can be securely and firmly electrically connected to a predetermined external electric circuit via the external lead terminals 7. .

When the Young's modulus of the external lead terminal 7 is less than 7000 kgf / mm ² , the rigidity of the external lead terminal 7 is insufficient and the external lead terminal 7 is easily deformed by applying a small external force. Workability of electrical connection to the external lead terminal 7
After connecting to the external electric circuit via solder or the like, the external lead terminal 7 swings when an external force is applied to the external lead terminal 7, and the external lead terminal 7 is connected to the external electric circuit in accordance with the swing. The external lead terminals 7
The reliability of the electrical connection to the external electric circuit will be greatly reduced, and if it exceeds 13000 kgf / mm ² , the flexibility of the external lead terminal 7 will deteriorate and the stress due to the application of external vibration will cause breakage. Will end up. Therefore, the external lead terminal 7 has a Young's modulus of 7,000 kgf / m.
It is specified in the range of m ^{2 to} 13000 kgf / mm ² .

A plating layer 9 made of nickel having a grain size of 2 μm to 5 μm is adhered to the exposed outer surface of the external lead terminal 7, and the plating layer 9 made of nickel.
As a result, the electrical connection between the external lead terminal 7 and the external electric circuit is improved, and the oxidative corrosion of the external lead terminal 7 is effectively prevented.

The plating layer 9 made of nickel having a grain size of 2 μm to 5 μm is formed on the exposed surface of the external lead terminal 7 by adopting an electrolytic plating method or an electroless plating method. In the case of forming by the method, for example, in a conventionally well-known Watt bath, that is, a nickel plating bath having a low nickel concentration in which the nickel concentration is lowered to about 40 g / liter in a plating bath composed of nickel sulfate, nickel chloride and boric acid. External lead terminal 7
And then 1 to 1.5 A / d on the external lead terminal 7.
by applying a plating power having a current density of about m ² or by adding a complexing agent or the like in the plating bath,
Controls nickel deposition (suppresses nickel plating rate)
By doing so, it is formed on the surface of the external lead terminal 7.

The plating layer 9 made of nickel has a nickel grain size of 2 μm to 5 μm, and since the grain size is large, dislocations are easily moved and easily deformed. Even if a strong vibration is applied to the package and the external lead terminals vibrate violently around the brazing portion as a fulcrum, and the stress due to the vibration acts on the plating layer 9 made of nickel, the stress appropriately deforms the plating layer 9 made of nickel. As a result, it is absorbed, and as a result, the plating layer 9 made of nickel does not crack or break.

When the grain size of the plating layer 9 made of nickel is less than 2 μm, there are many grain boundaries of crystals, and dislocations (regions where slippage occurs due to the external force of nickel atoms constituting each crystal do not occur). The movement of the boundary line between the area) becomes poor, making it hard and brittle, and difficult to deform,
When violent vibration is applied from the outside, cracks and fractures occur, and when the thickness exceeds 5 μm, a large number of pinholes (openings) are formed in the plating layer 9 made of nickel and the external lead terminals 7 are exposed. The surface cannot be completely covered, so that the external lead terminals 7 may be oxidized and corroded, or the reliability of electrical connection with an external electric circuit may be deteriorated. Therefore, the grain size of the plating layer 9 made of nickel is specified in the range of 2 μm to 5 μm.

Further, the plating layer 9 made of the above nickel
If the thickness is less than 1 μm, the wettability of the solder or the like to the external lead terminals 7 tends to deteriorate, and it becomes difficult to firmly electrically connect the external lead terminals 7 to the external electric circuit. When it exceeds, the stress generated during plating is inherent in the plating layer 9 made of nickel, and the internal stress tends to reduce the adhesion strength to the external lead terminal 7. Therefore, the plating layer 9 made of nickel has a thickness of 1 μm to 10 μm.
It is preferable to set it as the range of.

On the other hand, the insulating base 1 to which the external lead terminals 7 are attached has the lid 2 bonded to the upper surface thereof via a sealing material made of resin, glass, brazing material, etc.
With this, the concave portion 1a of the insulating base 1 is closed, and the semiconductor element 3 arranged in the concave portion 1a is hermetically sealed.

The lid 2 is made of a ceramic material such as an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride sintered body, or a metal material such as an iron-nickel-cobalt alloy or an iron-nickel alloy. For example, in the case of an aluminum oxide sintered body, a raw material powder of aluminum oxide, silicon oxide, magnesium oxide, calcium oxide or the like is formed into a plate shape by adopting a conventionally known press forming method and It is formed by firing at a temperature of about 1500 ° C.

Thus, according to the above-mentioned package for accommodating semiconductor elements, the semiconductor element 3 is formed on the bottom surface of the recess 1a of the insulating substrate 1.
Is bonded and fixed through an adhesive such as glass, resin, or brazing material, and each electrode of the semiconductor element 3 is electrically connected to the wiring layer 5 to which the external lead terminal 7 is attached by the bonding wire 6. After that, the lid body 2 is bonded to the upper surface of the insulating base body 1 through a sealing material made of resin, glass, brazing material or the like, and the semiconductor element 3 is hermetically sealed in the insulating container 4 made up of the insulating base body 1 and the lid body 2. The final product is a semiconductor device by being housed in.

A gold plating layer 10 is deposited on the upper surface of the nickel plating layer 9. As a result, the gold plating layer 10 further effectively prevents oxidative corrosion of the external lead terminals 7 and further improves the wettability of solder or the like, so that the external lead terminals 7 can be soldered to an external electric circuit. It is possible to make a stronger electrical connection via the.

The gold plating layer 10 is formed by a plating method such as an electrolytic plating method and an electroless method. For example, in the case of the electrolytic plating method, a conventionally known gold potassium cyanide-based plating bath is used. According to the standard method, the liquid temperature is 50 to 80 ° C,
The surface of the plating layer 9 made of nickel is adhered to a predetermined thickness by carrying out the work under a working condition of pH 4 to 7 for a predetermined time. In this case, since gold is a flexible material having extremely excellent ductility, the gold plating layer 10 will not be broken or the like due to vibration.

Further, in the above embodiment, the Young's modulus is 70.
Iron-nickel-cobalt alloy 8 is used as the external lead terminal 7 of 00 kgf / mm ^{2 to} 13000 kgf / mm ^2.
Although it has been explained that the one heat-treated and softened at a temperature of 00 ° C. or higher, preferably about 900 ° C. is used, the Young's modulus is 7
It is even better to use a metal material of 000 kgf / mm ^{2 to} 13000 kgf / mm ² together with an electric resistance of 50 μΩ · cm or less, so that the electric resistance is 50 μΩ · cm or less.

[0032]

According to the semiconductor element housing package of the present invention, the Young's modulus of the external lead terminals is 7,000 kgf /
mm ^{2 to} 13000 kgf / mm ^{2 having} a low flexibility, and the nickel plating layer deposited on the outer surface of the external lead terminal has a particle size of 2 μm to 5 μm.
Since the dislocations are easy to move and deform easily because of the large size of the package, a strong vibration is applied to the package for housing the semiconductor element, and the external lead terminals vibrate violently with the brazing part as the fulcrum, and the stress associated with the vibration causes the external lead Even if the stress is applied to the terminal, the stress is absorbed by the appropriate deformation of the external lead terminal and the nickel plating layer, and as a result, the external lead terminal is effectively prevented from breaking, and the stress is absorbed through the external lead terminal. Thus, it becomes possible to securely and firmly electrically connect the semiconductor element housed inside to a predetermined external electric circuit.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a semiconductor element housing package of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the semiconductor element storage package shown in FIG.

[Explanation of symbols]

1 ... Insulating substrate 1a ... Recess 2 ... Lid 3 ... Semiconductor element 4 ... Insulation container 5 ... Wiring layer 7: External lead terminal 9: Nickel plating layer

Claims (2)

(57) [Claims] 1. A wiring layer to which electrodes of the semiconductor element are connected is attached to an outer surface of an insulating container having a space for accommodating the semiconductor element therein, and an external lead terminal is brazed to the wiring layer. The external lead terminal has a Young's modulus of 7,000.
in electrical resistance kgf / mm ² or 13000kgf / mm ²
The resistance is 50 μΩ · cm or less , and the outer surface is composed of a plated layer of nickel having a grain size of 2 μm to 5 μm and gold.
A package for accommodating a semiconductor element, characterized in that it is coated with a plating layer . 2. The package for housing a semiconductor device according to claim 1, wherein the plating layer made of nickel has a thickness of 1 μm to 10 μm.