JPH06283623A - Semiconductor package - Google Patents

Abstract

PURPOSE:To provide a semiconductor package having a conductor pattern which can withstand high-temperature heat treatment without increasing the thickness of an Au-plating layer. CONSTITUTION:The package is obtained by constituting a conductor pattern formed on a ceramic substrate 1 by successively forming a W- or Mo-metallized layer 2, Hi-plating layer 3 composed of an Ni-W or Ni-Pd alloy, and Au-plating layer 4 on the surface of the substrate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor package in which a conductor pattern is provided on a ceramic substrate for mounting a semiconductor chip.

[0002]

2. Description of the Related Art Conventionally, various types of semiconductor packages have been known in which a conductor pattern for wire bonding or seal ring bonding is provided on a ceramic substrate for mounting a semiconductor chip. FIG. 2 is a diagram showing an example of the configuration of a conventionally known semiconductor package. In the example shown in FIG. 2, 11 is a ceramic substrate, 1
Reference numeral 2 is a pin for making an electrical connection to the outside, 13 is a die pattern used for mounting a semiconductor chip 15 made of, for example, Si, which is provided in the cavity 14 of the ceramic substrate 11, and 16 is a semiconductor chip 15 The wire bonding pattern 17 is electrically connected to the pin 12 through the ceramic substrate 11 used for wire bonding with, and 17 is a seal pattern for bonding a sealing cap (not shown).

Of the above-mentioned conventional semiconductor package constructions, it is preferable to use Au, which has good electrical characteristics, as the material for the conductor patterns of the die pattern 13, the wire bonding pattern 16 and the seal pattern 17, but the whole structure is preferable. However, there is a problem in that the cost increases if the is composed of only Au. In order to solve this problem, for example, FIG.
The film structure of the conductor pattern shown in FIG.
Japanese Patent Publication No.

The conductor pattern shown in FIG. 3 has a metallized layer 2 made of W or Mo provided on a ceramic substrate 11.
1, a Ni plating layer 22 made of a Ni—Co alloy provided on the metallized layer 21, and the Ni plating layer 22.
The Au plating layer 23 is provided on the top surface of the Au plating layer 23, and the amount of expensive Au used can be reduced while maintaining good electrical characteristics of Au.

[0005]

In recent years, the cavity 1 provided in the ceramic substrate 11 of the semiconductor chip 15 has been improved.
The semiconductor chip 15 is directly fixed in the cavity 14 by using Ag glass without fixing the die pattern 13 using Au described above. FIG. 4 is a diagram showing a configuration of an example of such a semiconductor package, in which 24 is an Ag glass adhesive layer used in place of the die pattern, and 25 is a resin die coat layer.

In order to manufacture a semiconductor package in which a semiconductor chip is fixed using such Ag glass, first, the semiconductor chip 15 is set in the cavity 14 via the Ag glass adhesive layer 24, and then 450 in dry air. ℃ × 20
After heat treatment for minutes, chips are attached, and wire bonding is performed. Then, the resin is heated in a nitrogen atmosphere at 450 ° C. × 60.
It was necessary to form the die coat layer 25 by performing heat treatment for a minute, and further perform cap sealing.

Therefore, as compared with the case of fixing the semiconductor chip by the conventional die pattern 13, the conductor pattern is exposed to high temperature, and the Au plating layer on the surface of the conductor pattern such as the wire bonding pattern 16 and the seal pattern 17 is oxidized. However, there is a problem in that the color changes due to the above, and the bonding property and sealing property deteriorate. In order to solve this problem, the thickness of the Au plating layer 23, which was 2 μm in the past, is 3.5 μm.
However, there is a problem in that the cost increases because a large amount of expensive Au must be used.

The object of the present invention is to solve the above problems,
An object of the present invention is to provide a semiconductor package having a conductor pattern that can withstand heat treatment at high temperature without increasing the thickness of the Au plating layer.

[0009]

In the semiconductor package of the present invention, the film structure of the conductor pattern provided on the ceramic substrate has a metallized layer made of W or Mo provided on the ceramic substrate, and a metallized layer formed on the metallized layer. Ni-provided
It is characterized by comprising a Ni plating layer made of a W alloy and an Au plating layer provided on the Ni plating layer.

Further, in the semiconductor package of the present invention, the film structure of the conductor pattern provided on the ceramic substrate is a metallized layer made of W or Mo provided on the ceramic substrate, and a Ni-layer provided on the metallized layer. Ni plating layer made of Pd alloy and A provided on this Ni plating layer
It is characterized by comprising a u plating layer.

[0011]

In the above structure, the Ni plating layer made of Ni-W alloy or Ni-Pd alloy provided between the metallization layer made of W or Mo and the uppermost Au plating layer in contact with the ceramic substrate is the Ni plating layer. It is possible to prevent heat diffusion to the Au plating surface layer, prevent discoloration of the Au plating layer, and withstand heat treatment at high temperature without increasing the thickness of the Au plating layer.

[0012]

1 is a view showing an example of a film structure of a conductor pattern in a semiconductor package of the present invention, and the wire banding pattern 16 and the seal pattern 17 of the semiconductor package shown in FIG. 4 have the film structure shown in FIG. Other than that, the configuration of the semiconductor package of the present invention is the same as the example shown in FIG. In the example shown in FIG. 1, the conductor pattern in the semiconductor package of the present invention has a metallized layer 2 made of W or Mo provided on the ceramic substrate 1 and a Ni-W alloy or Ni-made provided on the metallized layer 2.
The Ni plating layer 3 is made of a Pd alloy, and the Au plating layer 4 is provided on the Ni plating layer 3.

In the above-mentioned film structure of the present invention, W or Pd in the Ni plating layer 3 is Au of Ni in the Ni plating layer 3.
The present invention can be achieved if these compositions are present in the Ni plating layer 3 in order to prevent thermal diffusion into the plating layer 2, but in the case of Ni-W alloy, W: 5 to 90 wt%, Ni
Alloy: the balance is preferably composition, W: 10 to 70 wt
%, Ni alloy: The balance composition is more preferable, and Ni-P
In the case of the d alloy, the composition of Pd: 40 to 90 wt% and Ni alloy: balance is preferable, and Pd: 60 to 80 wt%,
The composition of the balance of Ni: alloy is more preferable. The composition of the balance includes a Ni alloy containing an impurity element such as Fe and Co.

In the case of Ni-W alloy, W: 5-9
0 wt% is preferable because if W is less than 5 wt%, the heat resistance may be poor and the effect of preventing Ni from diffusing into Au may be small, and if W exceeds 90 wt%, corrosion resistance may deteriorate. Is. Further, in the case of Ni-Pd alloy, Pd: 40 to 90 wt% is preferable because Pd is 40 w.
If it is less than t%, the heat resistance may be poor and the effect of preventing Ni from diffusing into Au may be small, and the Pd may be 90 w.
This is because if t% is exceeded, Pd is expensive and the cost also increases.

An actual example will be described below. Example 1 In order to evaluate the heat resistance of the semiconductor package, a semiconductor package made of a 256-pin pin grid array type alumina ceramic substrate having the structure shown in FIG. 4 was prepared.
The conductor patterns of the wire bonding pattern and the seal pattern were formed by forming a tungsten metallization layer on a ceramic substrate, and forming the tungsten metallization layer on the tungsten metallization layer with N of the present invention example and the comparative example having the compositions shown in Table 1 below.
An i-plated layer was applied to a thickness of 2.0 μm and heat-treated in a hydrogen atmosphere. Next, an Au plating layer having a thickness shown in Table 1 was applied on the Ni plating layer after the heat treatment to obtain a semiconductor package.

Thereafter, the heat resistance of the obtained semiconductor package was evaluated. The heat resistance was evaluated in dry air as a first step for the obtained semiconductor package.
Heat treatment is performed at 50 ° C. for 20 minutes, and as the second step, heat treatment is performed at 450 ° C. for 60 minutes in a nitrogen atmosphere, and then the Ni diffusion amount (wt%) on the surface of the Au plating layer is measured by an X-ray microanalyzer (XMA). I analyzed and asked. The results are shown in Table 1.

[0017]

[Table 1]

From the results of Table 1, Ni containing W of the present invention example
The one using the plated layer is a Ni containing no W of the comparative example.
It was found that both the wire bonding pattern and the seal pattern had better heat resistance than the one using the plated layer and could withstand high temperature heat treatment. In addition, among the examples of the present invention, Ni containing 5 to 90 wt% of W is used.
It was found that the plating layer had better heat resistance than the Ni plating layers having other W amounts.

Example 2 A semiconductor package was produced in the same manner as in Example 1 except that a Ni-Pd alloy was used as the Ni plating layer, and the obtained semiconductor package was subjected to heat resistance in the same manner as in Example 1. evaluated. The results are shown in Table 2.

[0020]

[Table 2]

The results in Table 2 also show that the one using the Ni plating layer containing Pd of the present invention has good heat resistance in both the wire bonding pattern and the seal pattern and can withstand high temperature heat treatment. It was In addition, it was found that among the examples of the present invention, the Ni plating layer containing 40 to 90 wt% of Pd had further better heat resistance than the Ni plating layer having the other amount of Pd.

[0022]

As is apparent from the above description, according to the present invention, a Ni- layer is formed between the metallized layer of W or Mo that is in contact with the ceramic substrate and the uppermost Au plated layer.
Since the Ni plating layer made of W alloy or Ni-Pd alloy is provided, it is possible to prevent thermal diffusion of the Ni plating to the Au plating surface layer, prevent discoloration of the Au plating layer, and increase the thickness of the Au plating layer. It can also withstand high temperature heat treatment.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an example of a film structure of a conductor pattern in a semiconductor package of the present invention.

FIG. 2 is a diagram showing a configuration of an example of a conventional semiconductor package.

FIG. 3 is a diagram showing a configuration of an example of a film structure of a conductor pattern in a conventional semiconductor package.

FIG. 4 is a diagram showing a configuration of another example of a conventional semiconductor package.

[Explanation of symbols]

 1 Ceramic Substrate 2 Metallization Layer 3 Ni Plating Layer 4 Au Plating Layer

Claims (2)

[Claims] 1. A film structure of a conductor pattern provided on a ceramic substrate is W or M provided on the ceramic substrate.
A semiconductor package comprising a metallized layer made of o, a Ni plated layer made of a Ni-W alloy provided on the metallized layer, and an Au plated layer provided on the Ni plated layer. 2. The film structure of a conductor pattern provided on a ceramic substrate is W or M provided on the ceramic substrate.
A semiconductor package comprising a metallized layer made of o, a Ni plated layer made of a Ni-Pd alloy provided on the metallized layer, and an Au plated layer provided on the Ni plated layer.