JPS6129165A - Lead frame material for ic and manufacture thereof - Google Patents

Abstract

PURPOSE:To perform a lead frame having excellent bondability and corrosion resistance by forming an aluminum alloy layer having the prescribed thickness or larger containing suitable amount of transition elements on a pure aluminum layer. CONSTITUTION:A pure aluminum 2 having 1mum or larger of thickness is deposited on one or both side surfaces of a substrate 1 made of iron alloy 1. Then, a layer 3 of aluminum alloy containing 0.1-2.0wt% of transition element is formed by sputtering in thickness of 0.2mum or larger on the layer 2. Thus, a lead frame for an IC having excellent bondability and corrosion resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lead frame material for IC and a manufacturing method thereof.

[Prior art]

As is already well known, a large number of I
JIF is formed in a single frame, each lead is connected to the terminal electrode of each semiconductor element, and after sealing and molding as an IC, each lead and frame are cut, and the cut portion of each lead is There is an embodiment in which the tip of the semiconductor element is used as a connection terminal to another electronic circuit member. Conventionally, the above-mentioned lead frame material has been made by vacuum-depositing pure aluminum to a thickness of 2 to 4 μm on a copper or copper alloy substrate. There is a problem with the corrosion resistance of the layer.
The reliability of the IC device may be impaired.

In order to improve the corrosion resistance of a deposited layer made of pure aluminum, it is possible to apply an aluminum alloy with excellent corrosion resistance. However, when forming this aluminum alloy layer, according to the vacuum deposition method, the composition of the layer film is extremely difficult to control, and it has been practically impossible to form such a layer.

Therefore, in the past, a thickness of 2 to 4 μm was applied using the s.
m, but in order to form an aluminum alloy film of such thickness, snow ξ
The problem with the tuttering method is that the rate of biofilm is slow (compared to conventional vacuum evaporation methods, production efficiency is poor).

[Purpose of the invention]

The present invention solves the problems in the conventional methods mentioned above,
1) -) 11 Frame material and its manufacturing method for a new IC that has excellent bending properties (connectivity to other electronic circuit components through the leads of the To) and corrosion resistance of the material, and has high manufacturing efficiency. The purpose is to provide

[Summary of the invention]

That is, the present invention provides a substrate made of copper or a copper alloy, or an iron-nickel alloy, and a substrate having a thickness of 1 μm provided on the substrate.
m or more pure aluminum layer, further provided on the pure aluminum layer with a thickness of 0.2 μm or more, especially 0.2 to 1 μm
A lead frame material for an IC characterized by comprising a layer of an aluminum alloy containing 0.1 to 20% by weight of a transition element of 0 μm, and a substrate made of copper, a copper alloy, or an iron-nickel alloy, by vacuum evaporation or ionization. Pure aluminum is deposited and layered to a thickness of 1 μm or more by vapor deposition,
Furthermore, 0.0% of transition elements are added onto the surface by snow ξ tuttering.
A layer of aluminum alloy containing 1 to 20% by weight with a thickness of 0.2
■0 characterized by being formed to have a thickness of μm or more
This is a method for manufacturing a P-frame material.

The present invention will be explained in detail below.

FIG. 1 shows a lead frame material according to the invention in a schematic cross-sectional view. In the figure, 1 is a substrate, 2 is a pure aluminum layer, and 3 is an aluminum alloy layer.

The substrate 1 of the IC lead frame material of the present invention is made of copper or copper alloy, or iron-based alloy such as iron, stainless steel, or iron-nickel alloy. It is the same material as the material for electric wires, and the copper alloy is mainly copper and contains Ag+Sn.
+ Zn + Fet Or + There are alloys to which small amounts of elements such as Zr and P are added. That is, the material of the substrate 1 does not need to be a material specially prepared for the present invention. In addition, as an iron-nickel alloy, Fe42N
i, Fe 36Ni, Fe-29Ni -170o
This is also a conventionally known material. The thickness of the substrate 1 is about 0.02 to 1 fI++++, which is the same as the conventional IC lead frame material.

Pure aluminum is deposited on one or both sides of the substrate 1 to a thickness of 1 μm or more by vacuum deposition or ionization deposition. This "pure aluminum" may contain about 0.02 to 2 weight percent of normal impurities. Vapor deposited layer 2
Vacuum deposition and ionization deposition are conventionally known means for forming I
This is a method in which a metal material to be deposited is heated and evaporated in a high vacuum of Torr or less, and the evaporated particles are deposited on a substrate to form a thin film. Ionization deposition, also called ion plating, is a method in which evaporated particles are passed through a plasma, ionized, accelerated by an electric field, and then attached to the substrate in order to increase the adhesion strength of the vacuum-deposited film to the substrate. be. All of these methods are conventionally known,
The implementation conditions and the operating method of the device used are appropriately selected and implemented for the present invention. The thickness of the pure aluminum layer 2 to be vapor-deposited is 1 μm or more, but if it is less than 1 μm, the vapor-deposited film will not be sufficiently deformed during the bending of the IC, resulting in poor contact etc., resulting in poor so-called zending properties. .

The most characteristic feature of the lead frame material of the present invention is that on each of the above pure aluminum layers 2, a layer 3 of an aluminum alloy containing 01 to 2.0% by weight of a transition element is further formed by starching. The reason is that it is formed to have a thickness of 082 μm or more. S, <+Tsuttering is a physical vapor deposition method in which, for example, argon gas is introduced into a glow discharge and ionized, and the ionized argon is accelerated and irradiated towards the aluminum alloy vapor deposition material. A thin film is formed by evaporating the vapor and depositing it onto the surface of the aluminum (alloy) layer on the substrate. This suction deposition method is classified in detail according to various matters such as ion generation mechanism, ion acceleration mechanism, and operating conditions. In general, sputtering deposition allows materials such as high melting point materials and alloys to be formed into thin films that are difficult to perform using normal vacuum deposition. The aluminum alloy used for the stratification in the present invention is mainly aluminum, ram,
And Fe, Oat Ni+ Ru+ Rh+ Pd
, Os, r r, Pt, etc. at 0.
It is an alloy containing 1 to 20% by weight. If the amount added is 0.1% by weight or less, the lower layer is pure aluminum.

It is not possible to impart sufficient corrosion resistance to the aluminum layer 2, and if the weight coefficient exceeds 2.0, the film becomes harder than necessary and causes a vapor deposited film during bending of the IC. Further, the thickness of the aluminum alloy layer 3 is required to be 0.2 fin or more, but if it is less than 0.2 fin, sufficient corrosion resistance cannot be imparted to the underlying pure aluminum layer 2;
, if it is 0 μm or more, it will cause a decrease in manufacturing efficiency due to snow ξ sagging. and made into a lead frame. I.J.
b% The shape of the frame is usually such that the connection part of the glue-P to the semiconductor electrode is placed in the center, and the connection to other electronic circuit members (
Zending) Place your feet on the radial line from the central connecting part,
It has a temporary shape in which the tip is temporarily connected to the outer frame (frame), and after placing the semiconductor element on the central connection part and connecting each electrode to the central connection part of the lead, the semiconductor element is attached to the synthetic resin. The rc is manufactured by sealing and molding, and then cutting out the frame around the reed part. Regarding these manufacturing steps, conventional methods may be used as they are, and detailed explanation thereof will be omitted in this specification.

〔Example〕

Example 1 5. on a 0.25 m thick copper substrate. OX 10-6To
The temperature of the substrate was 150°C with a degree of vacuum of rr, and the purity was 99.
99% aluminum was vacuum-deposited to a thickness of 20 μm, and then an Ar gas concentration of 3.0 μm was deposited on the formed aluminum layer. The substrate temperature was set to 150°C in an atmosphere of OX 10-6 Torr, and AI-N was
A sample according to the present invention (IJ −
1' frame material) was manufactured.

On the other hand, on the same steel substrate as above, a pure aluminum vapor deposited film having a thickness of 22 μm was formed by vacuum vapor deposition under the same conditions as a comparison sample.

In order to test the performance as a lead for the lead frame material according to the present invention manufactured in this way and a comparative sample, the wire bending property was determined by direct tL 3.
(Ultrasonic welding was performed using 1ltm Al-81 (1qA) for a brocade car, and both samples showed good weldability.Also, in the tensile test, the wire always broke in one part. However, both samples were heated at a temperature of 95°C and a humidity of 90°C.
% atmosphere, corrosion occurred on the surface of the aluminum layer after about 30 hours in the comparison sample, but corrosion did not occur in the sample according to the present invention until after 400 hours. was observed, indicating that it had significantly better corrosion resistance than the comparative sample, which was a conventional lead frame material.

Example 2 Samples were prepared in the same manner as in Example 1 by forming various deposited layers on a substrate. When the performance of each meal was evaluated, the results shown in Table 1 were obtained.

As shown in Table 1, the samples according to the present invention (<v-p frame material) were superior to the comparative samples in each evaluation item.

〔Effect of the invention〕

The lead frame material of the present invention exhibits significantly superior corrosion resistance compared to conventional lead frame materials, and has wire bending properties as good as those of conventional lead frame materials. The present invention has various effects such as high manufacturing efficiency, and is therefore an extremely excellent invention in practical terms.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of the lead frame material of the present invention. In the figure, 1 is a substrate, 2 is a pure aluminum layer, and 3 is an aluminum alloy layer. Yu 1 figure

Claims (3)

[Claims] (1) A substrate made of copper or a copper alloy, or an iron-nickel alloy, a pure aluminum layer with a thickness of 1 μm or more provided on the substrate, and a layer of 0.2 μm or more in thickness provided on the pure aluminum layer. 0.1 to 2.0 of transition elements
A lead frame material for an IC, characterized by comprising a layer of an aluminum alloy containing % by weight. (2) On a substrate made of copper, copper alloy, or iron-nickel alloy, pure aluminum is deposited to a thickness of 1 μm or more by vacuum evaporation or ionized evaporation, and then a transition element is added to 0 by sputtering. .1~2
．． A layer of aluminum alloy containing 0% by weight with a thickness of 0.2 μm
A method for manufacturing an IC lead frame material, which is characterized by forming the material as described above. (3) The thickness of the aluminum alloy layer is 0.2 to 1.0μ
The IC lead frame material according to claim (1), which is m.