JP2831182B2 - Electronic component having a gold conductive layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component having a gold conductive layer on a metal surface, and more particularly to a metal component in an electronic component such as a semiconductor device housing package for housing a semiconductor integrated circuit device or a multilayer wiring board. And improvement of the underlying metal layer of the conductive layer.

[0002]

2. Description of the Related Art Conventionally, semiconductor element housing packages for housing electronic components, for example, semiconductor integrated circuit elements,
A concave portion for mounting and housing a semiconductor element on the upper surface and a metallized wiring layer composed of a refractory metal powder such as tungsten, molybdenum, manganese or the like led out from the periphery of the concave portion to the outside are formed of an electrically insulating material such as alumina ceramics. An insulating base, an external lead terminal attached to a part of the metallized wiring layer via a brazing material such as silver brazing to electrically connect the semiconductor element to an external electric circuit,
A semiconductor element is mounted on the bottom surface of the concave portion of the insulating substrate with an adhesive made of glass interposed therebetween, and then the entire insulating substrate is heated to about 450 ° C. to heat the adhesive. The semiconductor element is melted and attached to the bottom surface of the concave portion of the insulating base, and each electrode of the semiconductor element is electrically connected to the metallized wiring layer through a bonding wire. Finally, a sealing member is provided on the upper surface of the insulating base. And a semiconductor device as a final product is obtained by hermetically sealing the semiconductor element in the concave portion of the insulating base.

The conventional package for housing a semiconductor element has a good electrical connection with a bonding wire or an external electric circuit on an exposed surface of a metallized wiring layer and a surface of an external lead terminal attached to an insulating base. In addition, a conductive layer made of gold for effectively preventing oxidative corrosion is layered by an electrolytic plating method or the like with a nickel plating layer provided on a base.

[0004]

However, in this conventional package for housing a semiconductor element, since the crystal of the gold conductive layer deposited by the electrolytic plating method is columnar, the semiconductor element is placed on the bottom surface of the concave portion of the insulating base. When heat is applied, for example, at the time of attaching the semiconductor element or at the time of hermetically sealing the semiconductor element housing package, the underlying nickel easily diffuses through the gold conductive layer, and as a result, the gold conductive layer surface Nickel is exposed to the surface and this generates oxides and hydroxides, making it difficult to electrically connect the external lead terminals to an external electric circuit in good condition, or to firmly bond the bonding wire to the metallized wiring layer. However, there is a disadvantage in that the coloration becomes difficult or discoloration causing poor appearance is generated.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and has as its object to effectively prevent the underlying nickel from diffusing into a gold conductive layer even when a high temperature is applied. It is an object of the present invention to provide an electronic component having a gold conductive layer that has good electrical connection with a bonding wire, enables strong bonding with a bonding wire or the like, and has no occurrence of discoloration that causes poor appearance.

[0006]

According to the present invention, there is provided an electronic component having a gold conductive layer on a metal surface, wherein a nickel plating layer and a gold nickel alloy plating layer or a gold cobalt alloy plating layer are used as bases of the gold conductive layer. Wherein a two-layer metal layer is provided.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

FIG. 1 is a cross-sectional view showing a semiconductor element housing package for housing a semiconductor element as an electronic component having a gold conductive layer according to the present invention. FIG. 1 shows an aluminum oxide sintered body and a mullite sintered body. An insulating base made of an electrically insulating material such as a body, an aluminum nitride sintered body, a silicon carbide sintered body, and the like, and 2 is a lid. The insulating base 1 and the lid 2 constitute a container 4 for housing the semiconductor element 3.

The insulating substrate 1 is provided with a recess 1a at the center of the upper surface thereof to form a cavity for accommodating the semiconductor element 3, and the semiconductor element 3 is provided with an adhesive 5 made of glass or the like on the bottom of the recess 1a. Is fixed via

When the insulating substrate 1 is made of, for example, an aluminum oxide sintered body, it is suitable for ceramic raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), magnesia (MgO), and calcia (CaO). Organic solvent and solvent are added and mixed to form a slurry, and this is formed into a ceramic green sheet (ceramic green sheet) by employing a doctor blade method, a calendar roll method, or the like. It is manufactured by performing appropriate punching, stacking multiple sheets, and firing at a high temperature (about 1600 ° C).

A metallized wiring layer 6 extending from the periphery of the concave portion 1a to the outside of the container 4 is formed on the insulating substrate 1, and each of the semiconductor elements 3 is provided around the concave portion 1a of the metallized wiring layer 6. Electrodes are electrically connected via bonding wires 7, and external lead terminals 8 connected to an external electric circuit are attached to portions led out of the container 4 via a brazing material such as silver brazing. .

The metallized wiring layer 6 is made of tungsten.
(W), a high melting point metal powder such as manganese (Mn), molybdenum (Mo), an organic solvent suitable for the high melting point metal powder,
A metal paste obtained by adding and mixing a solvent is applied to a ceramic green sheet serving as the insulating substrate 1 in advance by employing a known thick film method such as a screen printing method, so that the vicinity of the concave portion 1a of the insulating substrate 1 is formed. From the container 4 so as to be led out of the container 4.

The external lead terminals 8 brazed to the metallized wiring layer 6 serve to connect the semiconductor element 3 housed therein to an external electric circuit.
Is connected to an external electric circuit, so that the semiconductor element 3 housed inside is electrically connected to the external electric circuit via the metallized wiring layer 6 and the external lead terminals 8.

The external lead terminal 8 is made of Kovar metal (Fe-
Ni-Co alloy) and 42 alloy (Fe-Ni alloy), etc., and ingots (ingots) of Kovar metal etc. are rolled out or stamped out by adopting a conventionally known metal working method such as It is formed in the shape of a plate.

The metallized wiring layer 6 and the external lead terminals 8 also have a nickel plating layer 9 on the exposed surface thereof.
A gold conductive layer 11 is layered on an alloy plating layer 10 made of a gold nickel alloy or a gold cobalt alloy, and the gold conductive layer 11 improves the bonding strength of the bonding wire 7 to the metallized wiring layer 6. At the same time, the electrical connection of the external lead terminals 8 to the external electric circuit is improved, and the effect of effectively preventing the metallized wiring layer 6 and the external lead terminals 8 from oxidizing and corroding.

The gold conductive layer 11 is deposited in a thickness of 0.5 to 5.0 μm by a conventionally known electrolytic plating method.

The nickel plating layer 9 deposited as an underlayer of the gold conductive layer 11 acts to firmly adhere the gold conductive layer 11 to the surfaces of the metallized wiring layer 6 and the external lead terminals 8, The thickness of the metallized wiring layer 6 and the surfaces of the external lead terminals 8 are reduced to 0.5 to
Layered to 5.0 μm.

Further, an alloy plating layer 10 made of a gold-nickel alloy or a gold-cobalt alloy, which is deposited as an underlayer of the gold conductive layer 11, is formed by strongly depositing the gold conductive layer 11 on the nickel plating layer 9. Of nickel plating layer 9 effectively prevents diffusion to the gold conductive layer 11,
As a result, even when a high temperature is applied when the semiconductor element 3 is attached and fixed to the bottom surface of the concave portion 1a of the insulating base 1 via the adhesive 5, or when the package for housing the semiconductor element is hermetically sealed, even if a high temperature is applied, The nickel plating layer 9 never diffuses into the gold conductive layer 11 due to the alloy plating layer 10, and as a result, the discoloration caused by the diffusion and exposure of a part of the nickel plating layer 9 to the gold conductive layer 11 is suppressed. Occurrence is completely eliminated, and the electrical connection between the external lead terminal 8 and the external electric circuit and the electrical connection between the metallized wiring layer 6 and the bonding wire 7 can be made good and reliable.

The alloy plating layer 10 is layered between the nickel plating layer 9 and the gold conductive layer 11 by a conventionally well-known electrolytic plating method, and has a thickness in the range of 0.1 to 1.0 μm, more preferably 0.25 to 1.0 μm. To 0.5 μm.

When the alloy plating layer 10 made of the gold-nickel alloy or the gold-cobalt alloy is formed of an alloy containing 3.0 to 20.0% by weight of nickel or cobalt in gold, the gold plating layer 10 is applied to the gold conductive layer 11 of the nickel plating layer 9. Is extremely effectively prevented, and no discoloration or the like occurs in the gold conductive layer 11. Therefore, the alloy plating layer 10 is preferably made of 3.0 to 20.0% by weight of nickel or cobalt, preferably 7.0
To 15.0% by weight.

Thus, according to the above-mentioned semiconductor device housing package, the semiconductor device 3 is attached and fixed to the bottom surface of the concave portion 1a of the insulating base 1 via the adhesive 5, and each electrode of the semiconductor device 3 is bonded to the metallized wiring layer 6. Electrical connection is made via wires 7, and then a lid 2 is bonded to the upper surface of the insulating base 1 via a sealing material, and the semiconductor element 3 is hermetically sealed inside the container 4, thereby completing the final product. As a semiconductor device.

(Experimental Example) Next, the operation and effect of the present invention will be described based on the following experimental examples. First, a metallized wiring layer of tungsten is deposited on the surface of a substrate made of aluminum oxide sintered body, and a nickel plating layer having a thickness of 2.0 μm is formed on the surface, and a gold-nickel alloy or gold-cobalt alloy shown in Table 1 is formed. Gold plated layer and 1.5 μ thickness
20 samples each having an m 2 gold conductive layer sequentially deposited by electrolytic plating are prepared.

Next, each of the samples was placed on a hot plate whose surface temperature was controlled at 450 ° C. for 15 minutes, and the occurrence of discoloration after the placement was examined by a microscope. The good product rate was calculated by counting.

After placing each sample on a hot plate having a surface temperature controlled at 450 ° C. for 15 minutes, 35 bonding wires made of gold having a wire diameter of 30.0 μm were formed on the metallized wiring layer by an ultrasonic bonder. The bonding wires were pulled by a force of 10 g, and the number of the bonding wires peeled from the metallized wiring layer was counted to evaluate the bonding strength of the bonding wires.

Sample No. 15 is a comparative sample for comparison with the product of the present invention, in which a nickel plating layer and a gold conductive layer are sequentially deposited on a metallized wiring layer.

The results are shown in Table 1.

[0027]

[Table 1]

As can be seen from Table 1, in a conventional nickel plating layer in which a gold conductive layer is directly layered, a part of the nickel plating layer diffuses into the gold conductive layer when heat is applied, Discoloration of 10% occurs and 20 of the 35 bonding wires are peeled off to lower the bonding strength. On the other hand, in the product of the present invention, there is almost no discoloration due to diffusion of the nickel plating layer and the non-defective rate is 95%. % Or more, it can be seen that the bonding strength is extremely strong with almost no peeling of the bonding wire.

[0029]

As described above, according to the electronic component having the gold conductive layer of the present invention, the metal layer having a two-layer structure of the nickel plating layer and the gold nickel alloy plating layer or the gold cobalt alloy plating layer is used as the base of the gold conductive layer. Even when a high temperature is applied, such as when attaching and fixing a semiconductor element to a semiconductor element storage package via an adhesive, or when airtightly sealing the semiconductor element storage package, the nickel plating of the base is provided. The layer hardly diffuses into the gold conductive layer by the alloy plating layer. As a result, the occurrence of discoloration which causes the appearance defect in the gold conductive layer is minimized, and the electric connection between the external lead terminals and the external electric circuit is reduced. Good and reliable electrical connection between the metallized wiring layer and the bonding wire can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a semiconductor element housing package for housing a semiconductor element as an electronic component having a gold conductive layer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Insulating base 2 ... Lid 3 ... Semiconductor element 6 ... Metallized wiring layer 8 ... External lead terminal 9 ... Nickel plating Layer 10: Alloy plating layer 11: Gold conductive layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-96098 (JP, A) JP-A-62-56597 (JP, A) JP-A-2-174253 (JP, A) JP-A 61-96053 195991 (JP, A) JP-A-55-34692 (JP, A) JP-A-64-4479 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C25D 5 / 00-7 / 12 C23C 28/02

Claims (1)

(57) [Claims] An electronic component having a gold conductive layer on a metal surface, wherein a metal layer having a two-layer structure of a nickel plating layer and a gold nickel alloy plating layer or a gold cobalt alloy plating layer is provided as an underlayer of the gold conductive layer. An electronic component having a gold conductive layer, comprising: