JPS61195991A - Manufacturing method of electronic components - Google Patents

Abstract

PURPOSE:To increase the pelletizing properties and the solderability and to obtain the electronic parts high in the reliability by forming an Ni-Au alloy layer on the surface of metal. CONSTITUTION:An Ni-Au alloy layer is formed on the electronic parts, especially on the surface of metal of a package for a semiconductor. Or after performing the Ni plating on the surface of metal and performing the Au plating thereon, it is heat-treated to form the Ni-Au alloy layer on the surface of metal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to electronic components such as semiconductor package structures and methods of manufacturing the same.

[Background of the invention]

In recent years, there has been an increasing demand for improved reliability in semiconductor packages, but as the pellet size increases, it is necessary to increase the strength of the pellet attachment, and on the other hand, the conventional hermetic sealing method is used for sealing at low cost. In order to achieve this goal, glass sealing methods are increasing, and therefore heat resistance is required. Furthermore, in order to improve the reliability of mounting on devices, many semiconductor products are coated with solder, and most of the methods are solder dip. In response to this trend, the metal surface film structure of packages has conventionally been plated with As and Al4 plated on the surface.
Most of the base material is Nh film except for special products. However, as described above, as reliability increases, some conventional methods cannot meet the requirements. As an example of this, as the pellet size increases, there is a problem in which the pellet peels off from the Ni base layer during heat treatment such as pellet activation sealing. Furthermore, due to sealing heating, the Ni underlying the Aw layer is oxidized and the solderability deteriorates.

In order to solve such problems, Japanese Patent Application Laid-Open No. 55-3469
In 2, the N↓ plating as the base for AI- is replaced with Ni-Co.
.

Alloy plating is used to improve heat resistance and solderability, while also reducing the amount of Jg and Au used. Further, in Japanese Patent Application Laid-open No. 58-4955, a similar effect was obtained by using a thin plating as a barrier on the base of A%L. Meanwhile, 1984
IEEE (IBEE) No. 463~
“Failure of Gold” published on page 468
Silicon die attach by the presence on φ nickel silicide in the bonding
On Two Jar Size Dice Two Ceramic Chip Carriers (FAILURE OF G
OLD-8ILICON DIE-ATTACHBY
THE Pi(, E8ENCEOF NICKB
L 8ILICIDE IN THE BOND
ING OF LARGER8IZB DICE
To CB) LAMICCHIP-CARRIER8
) J points out that when large pellets are used, the stress between the substrate and the pellet increases due to the difference in thermal expansion between the ceramic substrate and the pellet, and the pellet peels off compared to the Ni medium, which has weak connection strength. This mechanism is that when pelletizing with A%-8↓ is heat-treated, 8L diffuses into Ni and a Ni-8↓ alloy is generated. The Ni-8↓ alloy (intermetallic compound) is mismatched with the base gold layer (Ni) and the crystal, and stress is generated at this boundary, resulting in a decrease in strength.

Therefore, pellet peeling occurs from this interface. As a countermeasure, it is necessary to prevent the formation of Ni-8↓ alloy. According to the above-mentioned literature, it has been determined that the diffusion of Ni-BL gold alloy beads is a rule, and it is stated that providing a barrier layer on Nb is a countermeasure to prevent the diffusion of Ni. There is. There are two ways to set up the barrier layer: one is to add CO to Ni, and the other is to add P. The mechanism is that CO does not form an alloy with S=, so Ni -Co is 8
C at the diffusion boundary that diffuses into L.

A rich layer is formed, which acts as a barrier and prevents the Ni-8↓ alloy from becoming an adult. It is said that P is also prevented by a similar mechanism. It also implies that similar effects can be obtained with other metals.d [Object of the Invention] The object of the present invention is to improve the pellet attachability and solderability of electronic components, especially semiconductor packages, and to Another object of the present invention is to provide a structure that can improve reliability.Another object of the present invention is to provide a manufacturing method for obtaining such a structure.

[Summary of the invention]

The surface of the package generally has a structure of Ni on an Aw base. Significantly changing this structure may cause unforeseen problems, and as a result of examining metals that can be used as barrier metals, it was found that As is effective.

Therefore, the present invention prevents the formation of Ni-8 and improves solderability by providing a Ni-As alloy on a metal surface using a mechanism similar to that of Co.

Furthermore, heat resistance can be improved.

[Embodiments of the invention]

Hereinafter, an explanation will be given using a flat type semiconductor package shown in FIG. 1, which is an embodiment of the present invention.

The semiconductor package is Guibondeng Bat 2a.

It has a wire bonding bat 2b and a leaded bat 2C, and these bats are metalized on the alumina ceramic 1 using a high melting point metal such as W or Mo.

These are formed using a screen printing method etc. before sintering the ceramic.

The batts 2a to 2c are formed by simultaneously sintering the batts 1 and 1.

Thereafter, 16 films 3 are formed on the bat by electroless plating or the like. Thereafter, the lead 5 is connected to the leaded bat 3 using, for example, eutectic silver solder 4.

Next, electrolytic N↓ plating is applied to all metal surfaces including the leads 5. Plating thickness is 1 to 6 μm, plating bath is Watt bath,
Or use a sulfamic acid bath. After that, electric AIL plating is applied to a thickness of 0.5 to 2 μm. For example, use gBJA's pure AS plating solution, Temperex 401.

Next, heat treatment is performed at 700 to 800° C. for 5 to 60 minutes in a reducing atmosphere. As a result, a Ni-A% alloy film 7 is formed. Next, electric A% plating 8 is performed again. The package is now complete.

The above example shows the method of forming a Ni-AI-alloy film by heat treatment, but the direct Ni-Aj & alloy plating method (
EEJA N↓-A% alloy plating solution, Autoronex W
.

Alternatively, a Ni-AsL film may be formed using N (plating thickness: 1 to 6 μm).

After the package is completed, semiconductor assembly will be performed.

First, the pellet 9 is bonded to a die bonding bat using an Am-8L eutectic solder 12, and after bonding the wire 10 using ultrasonic waves or the nail head method, hermetic sealing is performed with a cap 11 using a low melting point glass 13. A must for the next K IJ-do 5! According to the requirements, soldering is performed and the assembly is completed.

According to the present invention, even if a 101111 square pellet size is bonded with ksL-SL and sealed with low melting point glass (in air at 450°C) after wire bonding, there is no deterioration in the strength of the pellet attachment. The effect of the N, -Aw alloy film is great because very good results can be obtained in terms of the scratch resistance of the pick-up solder.

〔Effect of the invention〕

According to the present invention, pellet attachability and solderability are improved, and a highly reliable Kameko component can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view showing one embodiment of the present invention.
・Ceramic substrate 23-2C...metalized layer

Claims (1)

[Claims] 1. An electronic component structure characterized by forming a Ni-Au alloy layer on a metal surface. 2. After applying Ni plating on the metal surface and applying Au plating on it, heat treatment is performed, and Ni-A is applied on the metal surface.
A method for manufacturing an electronic component, comprising forming a u-alloy.