JPH0372045A - High strength and high conductivity copper alloy having excellent adhesion for oxidized film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a copper alloy suitable for lead materials for semiconductor devices such as transistors and integrated circuits, and conductive spring materials for connectors, terminals, relays, switches, etc. This invention relates to a high-strength, high-conductivity copper alloy with excellent film adhesion.

[Conventional technology]

Conventionally, lead materials for semiconductor devices have been Kovar (Fe-29Ni-16co) and 42 alloy (F
High nickel alloys such as e-42Ni) have been preferred. However, in recent years, as the degree of integration of semiconductor circuits has improved, the number of ICs with high power consumption has increased, resins have been increasingly used as sealing materials, and improvements have been made to the bonding between elements and lead frames. As a result, copper-based alloys with good heat dissipation properties have come to be used as lead materials.

Generally, lead materials for semiconductor devices are required to have the following properties.

(]) Relays are required to have the function of transmitting electrical signals as well as dissipating heat generated during the disassembly process and circuit use, so relays must exhibit excellent thermal and electrical conductivity. .

(2) Since the adhesion between the lead and the mold is important from the viewpoint of protecting the semiconductor element, the thermal expansion coefficients of the lead material and the mold material should be similar.

(3) Since various heating processes are added during packaging,
Good heat resistance.

(4) When various heating processes are added during packaging,
Good oxide film adhesion as an oxide film is formed between the resin and the material.

(5) Most leads are manufactured by punching or bending lead material, so the workability of these is good.

(6) Since the surface of the lead is plated with precious metals, the plating adhesion to these precious metals must be good.

(7) Exposed outside the sealing material after packaging;
Many items are soldered to the so-called outer leads, so good soldering is a sign of good soldering.

(8) Good corrosion resistance from the viewpoint of equipment reliability and lifespan.

(9) The price is low.

In addition, inexpensive brass, nickel silver, which has excellent spring properties and corrosion resistance, or phosphor bronze, which has excellent spring properties, have traditionally been used as spring materials for electrical equipment springs, measuring instrument springs, switches, connectors, etc. However, some connectors, terminals, etc. are sealed with resin, and oxide film adhesion is required.

[Problems to be Solved by the Invention] Conventional copper alloys such as oxygen-free copper, tin-containing copper, phosphor bronze and C
Precipitation hardening copper alloys such as u-Fe-P alloy and Cu-N1-P alloy have been used.

However, in recent years, the reliability of semiconductors has become more stringent, and surface mounting types that support miniaturization have become more common, so oxide film adhesion, which was not considered an issue in the past, has become an extremely important characteristic item. .

That is, since heat is applied to the lead frame during the packaging process, an oxide film is inevitably generated.

When sealed with a resin or the like, the adhesion strength between the resin and the oxide film, and the oxide film and the base material are compared, and the adhesion strength between the oxide film and the base material is generally low. In this case, peeling may occur between the oxide film and the base material, allowing moisture and the like to enter therefrom, significantly reducing the reliability of the IC. Therefore, oxide film adhesion is one of the most important properties for a high-strength, high-conductivity copper alloy used for lead frame materials and the like.

The aforementioned tinned copper, phosphor bronze and CLI-Fe-P
The oxide film adhesion of precipitation hardening type copper alloys such as alloys and Cu-Ni-5i alloys is worse than that of oxygen-free copper, and it has become impossible to satisfy the strict requirements for oxide film adhesion.

In addition, oxygen-free copper is no longer able to satisfy the demand for high strength due to miniaturization. Therefore, tinned copper, phosphor bronze, Cu-Fe-P alloy, Cu-Ni-
It has been desired to improve the oxide film adhesion of high-strength, high-conductivity copper alloys such as 3i alloy.

[Structure of the invention]

The present inventors conducted research in view of the above points and found that the addition of Mn is effective in improving the oxide film adhesion of high-strength, high-conductivity copper alloys. We have now provided a copper alloy that has properties suitable for use as a conductive spring material for relays, switches, and the like.

That is, the present invention contains Mn001% by weight or more and 10% by weight or less, and further contains B, P, Be, A as subcomponents.
l.

As%Sb%Si, Ti, Cr, Mg, Fe,
Co, Ni, Zr, Mo, Ag, Cd, P
b% Contains one or more selected from the group consisting of In, Hf, Sn, and rare earth elements in a total amount of 0.01% by weight or more and IO% by weight or less, and the remainder consists of CLJ and unavoidable impurities. A high-strength, high-conductivity copper alloy with excellent oxide film adhesion and a surface roughness of center line average roughness (R
a) 0.20μm or less, maximum height (Rmax) 1
．． The present invention relates to the high-strength, high-conductivity copper alloy with excellent oxide film adhesion as described above, characterized in that the thickness is 5 μm or less.

[Detailed Description of the Invention 1 Next, the reasons for limiting the alloy components constituting the alloy of the present invention will be explained.

By adding Mn to a copper alloy, it improves the adhesion of the oxide film of the copper alloy and also improves its strength. However, the reason why the I content is set to 0.1% by weight or more and IO% by weight or less is that .1
This is because if it is less than 10% by weight, there is no effect, and if it exceeds 10% by weight, the deterioration of workability and electrical conductivity is significant.

In addition, the subcomponents B, P%Be, Al, As, Sb
, Si, Ti.

Cr, (11g, Fe, Co, l'H1Zr,
One or more selected from the group consisting of Mo, Ag, Cd, Pb, In, Hf, Sn, and rare earth elements in a total amount of 0. The reason why OI is contained in OI weight% or more and 10 to 8 or less is because these elements can be added singly or in combination to improve strength without significantly reducing conductivity. If it is less than 10% by weight, there will be little improvement in strength, and if it exceeds 10% by weight, the electrical conductivity will drop significantly and the workability and soldering properties will deteriorate.

In addition, the surface roughness is 0.20μ in center line average roughness (Ra).
The reason for setting the maximum height (Rmax) to be 1.5 μm or less is to improve oxide film adhesion by smoothing the surface.

〔Example〕

Next, the present invention will be specifically explained.

Ingots (30 mm x 60 mm x 120
After melting the ingot (mm) and milling the ingot surface, 850
It was hot-rolled at ℃ to a thickness of 8M, and after facing, it was cold-rolled to a thickness of 1.5 mm. Thereafter, solution treatment was performed at 850° C. for 10 minutes, cooled at a rate of 10° C./sec or more, pickled, and cold rolled to a thickness of 0.25 mm+. These test materials were heated to 400°C in a vacuum annealing furnace to prevent the surface from being oxidized.
Aging treatment was performed at ℃ for a predetermined period of time. The surface roughness of the sample material was adjusted by changing the type of roll used in the final cold rolling.

As evaluation items for lead materials and spring materials, strength and elongation were measured by a tensile test, and bendability was measured by a 90" repeated bending test, where each round trip was counted as one time, and the number of bends until breakage was measured.
Electrical conductivity (heat dissipation) was shown by electrical conductivity (%IAC5). Solderability was evaluated by immersing the sample in a solder bath (860%, 40% lead) at 230±5° C. for 5 seconds using a vertical dipping method, and visually observing the state of solder wetting. The plating adhesion was determined by applying Ag plating with a thickness of 3μ to the sample at 450°C.
The sample was heated for 5 minutes, and the 3.P value was determined by visually observing the right front side of the blisters generated on the surface.

The spring properties were evaluated by measuring the spring limit straightness. Regarding oxide film adhesion, the material is heated at 200°C to 50°C.
An oxide film was formed on the surface by heating in the air at 0° C. for 3 minutes, and a sticky tape was attached to the oxide film, and then peeled off with air to evaluate whether or not the oxide film peeled off. The formation temperature of the oxide film at which peeling occurred was determined.

Table 1 will be explained below.

As is clear from Table 1, the alloy of the present invention has significantly superior oxide film adhesion compared to the comparative alloy.

Invention alloy floor 6.7.9 and comparison base metal consideration 16.17.20
have the same subcomponents, but the comparison alloy Nc16.17.
Since No. 20 does not contain Mn, the oxide film adhesion is poor.

Furthermore, although comparative alloy Nct18 is tough pitch copper, it lacks strength as a spring material. Also, comparative alloy N[L
19 contains only Mn and no subcomponents,
It lacks strength as a spring material.

[Effects of the Invention] The alloy of the present invention has sufficient mechanical strength, electrical conductivity, repeated bendability, solderability, plating adhesion, and oxide film adhesion, and is suitable for lead materials, connectors, terminals, and relays of semiconductor devices. It is suitable as a high-strength, high-conductivity copper alloy for use in switches, etc.

Below is Yoko

Claims (2)

[Claims] (1) Contains 0.1% by weight or more and 10% by weight or less of Mn,
Furthermore, as subcomponents B, P, Be, Al, As, Sb,
Si, Ti, Cr, Mg, Fe, Co, Ni, Zr, M
o, Ag, Cd, Pb, In, Hf, Sn, and one or more selected from the group consisting of rare earth elements in a total amount of 0.
．． A high-strength, high-conductivity copper alloy with excellent oxide film adhesion, characterized in that it contains 0.01% by weight or more and 10% by weight or less, and the remainder consists of Cu and unavoidable impurities. (2) Contains 0.1% by weight or more and 10% by weight or less of Mn,
Furthermore, as subcomponents B, P, Be, Al, As, Sb,
Si, Ti, Cr, Mg, Fe, Co, Ni, Zr, M
o, Ag, Cd, Pb, In, Hf, Sn, and one or more selected from the group consisting of rare earth elements in a total amount of 0.
．． The surface roughness is 0.20 μm or less in center line average roughness (Ra) and 1.5 μm or less in maximum height (Rmax). A high-strength, highly conductive copper alloy with excellent oxide film adhesion.