JPH02129349A - Manufacture of conductive parts material for electronic and electrical equipment - Google Patents

Abstract

PURPOSE:To obtain the title material having superior electric conductivity, thermal conductivity, solderability, etc., by subjecting a rolled Al alloy sheet containing respectively prescribed amounts of Cu and Mg to solution heat treatment, to cooling, and then to cold working to the final sheet thickness at a specific draft. CONSTITUTION:A rolled Al alloy sheet containing, by weight, 0.5-4.5% Cu and 0.2-2.0% Mg is subjected to solution heat treatment-hardening at 450-530 deg.C, cooled at >=1 deg.C/sec cooling rate, and then worked a 0-50% cold draft, by which a rolled sheet of the prescribed product sheet thickness, that is, usually of about 0.1-1.2mm sheet thickness is obtained. The above rolled Al alloy sheet has excellent repeated bendability and high strength equal to or higher than that of conventional 42 alloy, 'Kovar(R)', or Cu-type material, and further, it has superior electric conductivity, thermal conductivity, heat radiation characteristic, etc. Accordingly, this rolled Al alloy sheet can be suitably used as conductive parts material for electronic anc electrical equipment.

Description

[Detailed Description of the Invention] Industrial Field of Application This defense relates to a method for producing materials for electrically conductive parts of electronic and electrical equipment used in lead frames of semiconductors and ICs, or electrically conductive parts such as connectors and switches, and which has good electrical conductivity. The present invention relates to a method for producing a material for electrically conductive parts for electronic and electrical equipment that exhibits excellent thermal conductivity (heat dissipation), soldering properties, plating properties, mechanical strength, and especially excellent repeated bending properties.

Conventional Technology Typical conductive parts used in electronic and electrical equipment include individual semiconductor layers such as transistors. C,,L
There are lead frames used for SI and SCR. This lead frame is typically incorporated into an IC or semiconductor through the following steps.

First, a strip of conductive material with a thickness of 0.1 to 0.5 mm is prepared as a lead frame material, and the strip is punched or etched to form the desired lead frame shape (however, The outer leads are connected to each other), and then a semiconductor element (Si chip) made of high purity 5i or the like is bonded to a predetermined location of the lead frame.

This bonding is called die bonding, and is performed by pressure bonding using a conductive resin such as Ag paste, or by attaching Au, A plating layer consisting of a single layer or a multilayer of two or more of ACt, Ni, etc. is formed in advance, and heat diffusion pressure bonding is performed through this plating layer using eutectic such as ALJ-3i. There are methods of bonding a lead frame and a semiconductor element, and a method of bonding using Pb-8n solder or the like. Thereafter, the β electrode on the semiconductor element (Si chip) die-bonded to a predetermined location of the lead frame on the substrate and the conductor terminal (inner lead) of the lead frame are connected by an ALJ wire or an Al wire. This connection is called wire bonding. Subsequently, in order to protect the semiconductor element, the wiring part, and the part of the lead frame where the semiconductor element is attached, it is sealed with resin, ceramic, etc., and the parts of the lead frame where the lead frame is connected to each other are cut off. .

The lead frame material used through the above processes must have good press workability or etching properties, and must have good heat resistance (softening resistance) during the die bonding process between the semiconductor element (Si chip) and the lead frame. It must have good heat dissipation (thermal conductivity) and conductivity, as well as good plating and soldering properties, as well as good resistance to bending and repetition when transporting semiconductor devices or incorporating them into electronic equipment. It is required to have mechanical strength that does not cause fractures when bent, excellent repeated bending resistance, and corrosion resistance.

Conventionally, such lead frame materials include Fe-42
%N; 42 alloy, or “017%Co-
Kovar, which is a 29% Ni alloy, as well as phosphor bronze (CA 501), which is a CLI alloy, and Cu-Fe-Zn-
P (CA 194) alloy, Qu-1”e-co-sn
-p (CA 195) alloy etc. are used.

Problems to be Solved by the Invention Both Kovar and 42 alloys, which are conventionally used as lead frame materials, are expensive because they contain a large amount of expensive Ni, and Cu-based alloys have poor repeatability. It was inferior, and there was also a problem in terms of price. Therefore, there is a strong desire to develop and put into practical use a material that satisfies the electrical properties required for these parts and is inexpensive and can be used as a conductive material for conductive parts of electronic and electrical equipment such as lead frame materials.

Aluminum alloy is generally known as an inexpensive conductive material, and lead frame materials using aluminum alloy have already been published in JP-A-62-96638 and JP-A-62-96638.
The method described in No. 2-96644 and the like has been proposed. However, compared to conventional lead frame materials such as 42 alloy and phosphor bronze, these aluminum alloys have lower strength and do not have sufficient repeated bending properties. Opening of the base material is desired.

This invention was made against the background of the above circumstances, and has particularly excellent repeated bending properties, high mechanical strength, and other properties such as electrical conductivity, thermal conductivity (heat dissipation), and solderability. The object of the present invention is to provide a method for producing a material for electrically conductive parts for electronic and electrical equipment made of an aluminum-based alloy that has excellent adhesion and plating properties.

Means for Solving the Problems The present inventors have developed an aluminum-based alloy that has the characteristics necessary as a material used in electrically conductive components of electronic and electrical equipment such as lead frame caps, particularly excellent repeated bendability and high strength. As a result of repeated experiments and studies on ingredients and manufacturing methods that would satisfy the requirements, this invention was achieved.

Specifically, the method for producing a material for electrically conductive parts of electronic and electrical equipment according to the invention of claim 1 includes Qu0.5 to 4.5%, Mg0.2
Contains ~2.0% and the remainder is 8! and an aluminum alloy rolled plate consisting of unavoidable impurities at 450 to 530°C.
solution treatment and cooling at a cooling rate of 1°C/dew or higher,
It is characterized in that the h-loe ratio of the subsequent cold working is set at 0 to 50% to obtain a material with a final plate thickness.

Further, the method of the invention of claim 2 further includes subjecting the material having the final plate thickness obtained by setting the cold working rate after the solution treatment to 0 to 50% as described above to further final treatment at 100 to 220°C. It is characterized by:

Furthermore, in the method of the invention of claim 3, in addition to the above-mentioned CLI and Mg, Mn 1.0% or less, Qr 0.3% or less, Zr 0.3% or less, V 0.3% or less, Ni5 A material containing one or more of .7% or less is used, and is not subjected to the same treatment as the invention of claim 1.

Furthermore, the method of the invention of claim 4 is similar to claim 3, in which the material alloy components include Mn, Cr, and Zr in addition to Qu and MQ.
, V, Ni or two or more of the following, and the final plate thickness obtained by using a material containing one or more of Tah, V, and Ni, and using a cold working rate of 0 to 50% after solution treatment as in claim 2. The material is further subjected to a final heat treatment at 100-220°C.

Function: An Aj7-Cu-Mq alloy, which is a heat-treatable alloy having age hardening properties, is used as the wooden aluminum base metal in the method for manufacturing electrically conductive parts materials for electronic and electrical equipment according to the present invention.

Here, the A&-Cu-Mq alloy is defined as having Qu as an essential alloy component of 0.5% (wt%, same hereinafter) or more, 4.5%
% or less, and Mg is contained in an amount of 0.2% or more and 2.0% or less. Next, the reason for limiting the content of Cu and MQ will be explained.

Cu: Cu is an element that not only contributes to strength improvement but also improves plating and solderability. However, if Cu is less than 0.5%, the effect of improving strength cannot be sufficiently obtained; on the other hand, if it exceeds 4.5%, If it is contained, rolling properties will be reduced and rolling will become difficult. Therefore, CIJ was set within the range of 0.5 to 4.5%.

Mq: Mg is an element that forms precipitates when coexisting with Qu and contributes to improving strength, and is necessary to obtain the strength and repeated bending resistance required for parts such as lead frames. However, if the content is less than 0.2%, a sufficient strength improvement effect cannot be obtained, and on the other hand, if the content exceeds 2.0%, there is no significant improvement in strength, and moreover, the rolling properties are extremely reduced. Therefore, Mq was set within the range of 0.2 to 2.0%.

The aluminum-based alloy used as a material for electrically conductive parts of electronic and electrical equipment according to the present invention basically contains the above CIJ and MCI. A 17-Cu-Mch based alloy can ensure the necessary mechanical properties for parts such as lead frames, but in order to further improve heat resistance (softening resistance), in the invention of claim 3 or claim 4, , Mn 1.0% or less, Qr
0.30% or less, Zr 0.30% or less, V 0.30%
Hereinafter, one or more types of Ni of 5.7% or less may be added. The reason for limiting the amount of these elements added in the invention of claim 3 or claim 4 is as follows.

Mn: Mn is solution treated yf! It is an effective element for further improving strength and improving heat resistance (softening resistance) by making the recrystallized grains finer, but even if it is contained in an amount exceeding 1.0%, it will not improve strength or heat resistance. The effect of improving sex is saturated, and solution 9
8 Increased susceptibility to immediate quenching, making manufacturing difficult. Therefore, the amount of Mn added was set to 1.0% or less.

Cr: Or is also an effective element for refining recrystallized grains during solution treatment and further improving strength and heat resistance.
Even if the content exceeds 30%, the effects of improving strength and heat resistance are saturated, and large compounds are likely to be formed during casting. Therefore, the amount of Or added was set to 0.30% or less.

Zr: Zr is also an effective element for refining recrystallized grains, improving strength, and improving heat resistance, but even if it is contained in amounts exceeding 0.30%, the effects of improving strength and heat resistance are saturated, and The amount of zr added was set to 0.30% or less since it becomes easy to generate huge compounds during casting.

V: ■ is also an effective element for refining recrystallized grains, improving strength, and improving heat resistance, but even if it is contained in an amount exceeding 0.30%, the effect of improving strength and heat resistance is saturated; Since it becomes easier to generate giant compounds during casting, the amount of ■ added is 0,
It was set to 30% or less.

Ni: N1 is also an effective element for refining recrystallized grains, improving strength, and improving heat resistance, but even if it is included in amounts exceeding 5.7%, the effects of improving strength and heat resistance are saturated. Also, the amount of Ni added was set to 5.7% or less since it would be easy to generate huge compounds during casting.

In addition to the above-mentioned components, AI2 and inevitable impurities may be used. Usually, Fe and 3i are contained as unavoidable impurities, but these Feff1.5iff
If i increases, the crystallized material size increases and the repeat bendability decreases, so it is desirable to keep Fe at about 0.50% or less and Si at about 0.30% or less, and more preferably Fe It is desirable that Si be 0.30% or less and Si be 0.15% or less.

In addition, in the production of aluminum alloy ingots, Ti or -'i and B are generally added in order to refine the ingot crystal grains. Even if B is added, there is no problem in using it as a conductive component material for electronic and electrical separators such as lead frame materials.However, the amount added is Ti0.2% or less, [3
0.04% or less is desirable.

Furthermore, when casting A2 alloys containing Mg, such as the aluminum-based alloys of this invention, Be may be added as necessary to prevent oxidation of the molten metal or to improve rollability. , in the case of this defense material, 50 pprn Pi! Can be added below

Next, the manufacturing method of the electronic electrical separator conductive component material of this defense will be described in detail.

First, a molten aluminum base metal having the above-mentioned composition is cast in accordance with a conventional method. Semi-continuous casting method (DC casting method) is used as this casting method, but from the viewpoint of energy saving and improvement of softening resistance, thin plate continuous casting method (continuous rolling method) is also applied. good.

The obtained flange block is subjected to soaking treatment (homogenization treatment) and hot rolling, and then cold rolling and then solution treatment and quenching. This solution treatment and quenching is a necessary step to increase strength. After performing the solution treatment and quenching in this manner, a rolled plate having a predetermined product thickness is obtained at a cold working rate of 0 to 50%. That is, cold working is not performed, or even if cold working is performed, the working rate is small, 50% or less. Note that the inside of the film has a thickness of about 0.1 to 1.2 inches, which is the product thickness. However, in the case of continuously cast thin sheets, the steps up to hot rolling can be omitted among these steps.

Among the above steps, the soaking treatment may be maintained at a temperature of 450 to 530°C for within 48 hours. Soaking temperature is 450℃
If the temperature is lower than 530°C, the hot rolling properties will decrease.
If the value exceeds 100%, eutectic melting is likely to occur.

Furthermore, even if the holding time exceeds 48 hours, the effect of homogenizing the structure due to soaking is almost saturated, which only results in an increase in energy costs.

After the scorching heat treatment, the material is usually reheated and then hot rolled.

This reheating may be carried out at 450 to 530°C according to a conventional method, and hot rolling may also be carried out at 450 to 530°C. In addition, heating for scorching treatment (homogenization treatment) and hot rolling! 2! l
! It is not necessary to perform the rolling separately as described above, and a single heat treatment may be performed to serve as both the homogenization treatment and the heating for hot rolling, followed by hot rolling.

After the hot rolling is completed, a second cold rolling is performed to obtain a rolled plate intermediate, and this rolled plate intermediate is further subjected to solution treatment and quenching. Solution treatment and quenching are for pre-dissolving elements such as M (J, CLJ, etc.) in order to impart age hardenability, and the solution treatment temperature is 450 to 530.
The temperature must be within the range of °C. If the solution treatment temperature is less than 450°C, the subsequent age hardenability and work hardenability will deteriorate, making it impossible to obtain sufficient strength. On the other hand, if the solution treatment temperature exceeds 530°C, eutectic melting will occur, which is undesirable. Further, the holding time at the solution treatment temperature varies depending on the plate thickness, but if the plate thickness is 1 mm or less, holding for 40 minutes or less is sufficient. Cooling (quenching) after holding at the solution treatment temperature achieves a cooling rate of 1°C/511c or more. If the cooling rate is less than 1°C/sec, age hardening will be low and work hardening will also be low, making it impossible to achieve sufficient strength, so it is necessary to set the cooling rate to 1°C/s or more. Note that when performing this solution treatment on a coil-shaped rolled plate intermediate, a continuous annealing furnace is usually used.
In the case of continuous annealing, the cooling rate is 1℃ even if the holding time is short.
/ or more, the subsequent age hardenability and work hardenability will not be significantly impaired.

After solution treatment and quenching, it may be used as a product sheet as is, but if necessary, cold rolling or leveling may be applied to increase the strength or correct distortion during quenching. You can perform mamae■. however,
Excessive cold working will reduce the repeatability of bending, so in this invention we use solution processing to obtain particularly excellent repeatability! LIyJl, the cold working rate after quenching needs to be within the range of 0 to 50%. If the cold working ratio exceeds 50%, the strength will increase, but the repeat bendability will decrease, which will not meet the purpose of the present invention.

Regarding the strength of the final rolled plate, conventional 42 alloy and CLJ
In order to obtain performance equivalent to or higher than that of lead frame materials for electronic and electrical equipment such as lead frame materials of 54-based alloys, the tensile strength must be 40.
klIF/nr- or more, repeated bending three or more times is required, but in the case of the aluminum base alloy material produced by the method of the present invention as described above, both strength and repeated bendability can be sufficiently satisfied with the values of 1J. .

In addition, in the case of the method of the invention of claims 2 and 4, in order to further improve the repeatability, the above-mentioned
100~22 after making the final plate thickness with a cold working rate of 50%
Final annealing is performed at 0°C. If the final annealing temperature is less than 100°C, there is little improvement in elongation, so repeat bendability does not improve much. On the other hand, if the final annealing temperature exceeds 220°C, elongation improves and repeat bendability improves, but strength decreases. I ended up
Moreover, depending on the temperature, over-aging may occur and the repeated bending property may deteriorate. Therefore, the final annealing is 1
It is necessary to carry out the process within the range of 00 to 220°C.

Example 7 alloy No. 7 shown in Table 1. 1~N0. 3 was cast using the normal semi-continuous M manufacturing method. The semi-continuously cast Shikoh has a thickness of 500 rnm with each side facing up, and a width of +000/lIn.
, the length is 3500 rnrn, and the manufacturing conditions shown in Table 2 are No. 0. A rolled plate with a thickness of 0.30 was obtained by measuring 1 to N0.6.

These aluminum alloy rolled plates were investigated for tensile strength, repeated bending properties, electrical conductivity, plating properties, and soldering properties. The results are shown in Table 3.

Note that the tensile test was conducted after being left at room temperature for 7 days after solution treatment and quenching. In cases where final annealing was required, the specimens were solution-treated for 98 hours and then strangled at room temperature for 7 days before final annealing and then subjected to a tensile test.

Furthermore, in the case of aluminum alloys, in order to perform plating such as ALJ or Act, it is generally necessary to perform surface treatment in advance before plating. Also, when applying solder, use the surface 'l! If you do this in advance, the solder will stick more easily and the parts will be less likely to peel off during soldering. Such preliminary surface treatment is generally performed using N
There are 1 plating and Cu plating, and zincate treatment is effective as a pretreatment for this surface treatment. The more uniform the distribution of Zn during this zincate treatment, the better the plating properties of Ni and CLI on the zincate treated surface, and the better the plating properties and soldering properties of Au and AQ applied thereon. Becomes good. Therefore, in this example as well,
To determine the plating and soldering properties, a rolled plate is subjected to zincate treatment, and the Zn distribution on the zincate-treated surface is observed with an optical microscope.
, rated as ×. If it is △ or above, the plating and soldering properties are determined to be acceptable. The zincate treatment conditions are as follows.

Bath composition: NaO 8525g/& zinc oxide 98g/l Bath temperature 220°C Immersion time: 30 seconds Also, the repeated bendability was 90' for the rolled material of 0.30rRm.
Bending was repeated with one swing, and the number of reciprocations until breakage was measured. There is no problem in terms of performance as long as this repeated bendability is 3 or more times.

As is clear from Table 3, the aluminum-based alloy used as a material for electrically conductive parts of electronic and electrical equipment produced by the manufacturing method of the present invention has sufficient strength when rolled as a tensile strength of 40 M/IRd or more. Not only does it have excellent repeat bendability, but it also has a much higher electrical conductivity than 42 alloy (conductivity 31AC8%), which is the conventional lead frame material. Furthermore, since the uniformity of Zn during the zincate treatment was good, it was found that the plating and soldering properties were excellent. Although not particularly shown in Table 3, it has been confirmed that corrosion resistance and heat dissipation (thermal conductivity) are also excellent.

Effects of the Invention According to the manufacturing method of the present invention, it has excellent repeated bending properties, has high strength equivalent to or higher than conventional 42 alloy, Kovar or CU-based materials, and has good electrical conductivity and thermal conductivity. It is possible to obtain an aluminum-based material for electrically conductive parts of electronic and electrical equipment, which has heat dissipation properties and also has good soldering and plating properties. Therefore, it is ideal for manufacturing lead frame materials for IC1 semiconductors that require these characteristics, and materials for electrically conductive parts of electronic and electrical equipment such as switches and connectors. In particular, when performing Soi 1 bonding with Soi 2 wire in lead frame materials, if the material produced by the manufacturing method of the present invention is used as the lead frame,
There is no need to apply gold plating, silver plating, etc. to the semiconductor element mounting part and the wire connection part, and wire bonding can be performed as is, which has the advantage of further reducing the cost of semiconductor element manufacturing.

Claims (4)

[Claims] (1) Cu0.5-4.5% (weight%, same below), M
An aluminum alloy rolled plate containing 0.2 to 2.0% of g, with the remainder consisting of Al and inevitable impurities,
Conductive electronic and electrical equipment characterized by solution treatment at 530°C, cooling at a cooling rate of 1°C/sec or more, and subsequent cold working at a processing rate of 0 to 50% to obtain a material with a final plate thickness. Method of manufacturing materials for parts. (2) A rolled aluminum alloy plate containing 0.5 to 4.5% of Cu and 0.2 to 2.0% of Mg, with the balance consisting of Al and unavoidable impurities, is solution-treated at 450 to 530°C, The material is cooled at a cooling rate of 1°C/sec or more, and the resulting material has a final thickness of 0% to 50%, and is further subjected to final heat treatment at 100°C to 220°C. A method for manufacturing a material for electrically conductive parts of electronic and electrical equipment. (3) Contains Cu0.5-4.5%, Mg0.2-2.0%, and further includes Mn1.0% or less, Cr0.3% or less,
An aluminum alloy rolled plate containing one or more of Zr 0.3% or less, V 0.3% or less, and Ni 5.7% or less, with the balance consisting of Al and inevitable impurities,
Solution treatment at 450-530℃, cooling rate 1℃/s
Cool at ec or higher and reduce the processing rate of subsequent cold working from 0 to 5.
A method for producing a material for electrically conductive parts of electronic and electrical equipment, characterized by obtaining a material with a final plate thickness of 0%. (4) Contains Cu0.5-4.5%, Mg0.2-2.0%, and further includes Mn1.0% or less, Cr0.3% or less,
An aluminum alloy rolled plate containing one or more of Zr 0.3% or less, V 0.3% or less, and Ni 5.7% or less, with the balance consisting of Al and inevitable impurities,
Solution treatment at 450-530℃, cooling rate 1℃/s
Cool at ec or higher and reduce the processing rate of subsequent cold working from 0 to 5.
The final thickness of the material obtained as 0% is further increased by 100~
A method for producing a material for electrically conductive parts of electronic and electrical equipment, characterized by subjecting it to final heat treatment at 220°C.