JP2732490B2 - Manufacturing method of high strength and high conductivity copper alloy for electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a high-strength, high-conductivity copper alloy for electronic equipment, and more particularly, to a lead for semiconductor equipment such as transistors and integrated circuits (ICs). The present invention relates to a method for producing a copper alloy suitable for a material and having excellent etching properties and bending workability in addition to high strength and conductivity.

[0002]

2. Description of the Related Art It is said that the trend of IC packages is to make them lighter and thinner. However, recently, the tendency is increasingly promoted by the spread of surface packages. Furthermore, as the number of pins and the thermal resistance of IC chips have increased due to the higher functionality of IC chips, the trend of package form has shifted from pin insertion type packages typified by DIP, which has been widely diversified, to surface mounting for the purpose of increasing mounting density. SOJ, SO
It has shifted to surface mount packages such as P and QFP.
Recently, fine pitch QFPs with a reduced lead pitch have been increased along with the increase in the number of pins, and packages such as TSOP and TQFP have become thinner.

[0003] A frame having a large number of pins and a narrow pitch is mostly formed by etching, but etching involves not only the thickness direction but also side etching in the width direction, so that the lead width and lead spacing are processed. The limit depends on the plate thickness, and the smaller the plate thickness, the more advantageous in processing. In addition, due to the demand for thinner packages, it is necessary to reduce the thickness of the lead frame material.
→ 0.125 mm → 0.10 mm. Such thinning of the lead frame and narrowing of the leads reduce rigidity of the entire frame and the leads, causing deformation of the inner leads during the assembly process and deformation of the outer leads during device mounting.

The following characteristics are generally required for such lead frame materials for semiconductor devices. (1) The inner lead or the outer lead has a mechanical strength that is not easily deformed. (2) To have excellent etchability and press workability in forming a lead frame pattern. (3) It has a high thermal conductivity capable of efficiently dissipating heat generated by the lead frame. Since the power consumption increases as the IC density increases and the number of pins increases, measures to dissipate the heat generated are an important issue in IC design. Copper alloys have an advantage in heat dissipation because copper originally has properties of much higher than 42 alloys in thermal conductivity. (4) Excellent electrical characteristics. (5) Excellent solderability in mounting and high reliability of solder joints. (6) Excellent Ag plating for bonding. (7) The copper alloy surface is excellent in thermal oxidation resistance, which is not easily oxidized in the heating step. (8) It is excellent in repeated bending property. (9) Appropriate price. Although the performance required for the lead frame material of the semiconductor device has been described above, the present invention is also used as a material for other electronic devices requiring the same performance.

However, with respect to these various required characteristics, conventionally used phosphor bronze, Kovar (trade name) and 42 alloy all have advantages and disadvantages, and cannot satisfy all of the above characteristics. Was. In particular, it is necessary to take into account the fact that the shape of the lead is becoming more complicated and the pin is becoming narrower as the number of pins and the size of the lead are increased, and materials are required to have better lead strength, etching properties and bending workability. For example, it was difficult to say that the conventional material had sufficient performance in these respects.

Further, Cu—Cr—Zr alloys for electronic devices are known per se, and are disclosed, for example, in Japanese Patent Application Laid-Open No. 5-117789.
According to the publication, a method of hot-rolling a semi-continuous cast ingot, cold-rolling after double-sided surface grinding, is employed as a method for producing the same. However, sufficient properties cannot be obtained by this processing method.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a Cu-Cr-Zr-based alloy that makes use of the excellent electrical characteristics and heat conductivity of a copper-based material, and at the same time, is sufficient as a lead material for semiconductor equipment. Strength, spring characteristics,
An object of the present invention is to provide a method for producing a copper alloy having both etching properties and bending workability.

[0008]

According to the present invention, (a) Cr: 0.05 to 0.4% by weight and Zr: 0.03 to
A copper alloy containing 0.25% and a balance of Cu and inevitable impurities, (b) Cr: 0.05 to 0.4
%, Zr: 0.03 to 0.25%, Zn: 0.06 to
Copper alloy containing 2.0% and the balance being Cu and unavoidable impurities, or (c) Cr: 0.05 to
0.4%, Zr: 0.03 to 0.25%, and Zn:
0.06 to 2.0%, and further contains Ti, Fe, Ni,
At least one of Sn, In, Mn, P, Mg and Si: containing not less than 0.01 to 1.0% in total, and the balance Cu
And a method for producing a high-strength and high-conductivity copper alloy for electronic equipment comprising unavoidable impurities, comprising: (a) solution treatment by any of the following methods: (a) annealing at a temperature of 700 ° C. or more; solution heat treatment performs water cooling continuously; (b) hot rolling end temperature of 700 ° C. or higher, hot rolling to perform water cooling at 100 ° C. / min or more cooling rate immediately thereafter, (b) working ratio 20 (C) aging treatment at a temperature of 300 to 700 ° C, (d) cold rolling at a workability of 30% or less, and (e) strain relief annealing at a temperature of 350 to 700 ° C Etching characterized by sequentially performing the steps of
The present invention relates to a method for producing a high-strength and high-conductivity copper alloy for electronic equipment , which has excellent characteristics . The solution treatment is to form a solid solution of Cr and Zr.
And Ti, Fe, Ni, Sn, In, Mn, P, Mg and
When one or more of Si and Si are contained,
To prevent the formation of balding inclusions of Cr
U. In the present invention, “excellent in etching properties” refers to pressure.
5 μm on the etched surface of the hole opened by etching
That is, there is no protrusion .

Cr Cr precipitates alone in the matrix when the present alloy is subjected to aging treatment, and exhibits the effect of improving the strength and heat resistance of the alloy. Is insufficient, the desired effect cannot be expected. On the other hand, if the Cr content exceeds 0.4%, undissolved Cr remains in the mother phase as a Cr phase even after the solution treatment, and as a result, , Exists as a whisker-like inclusion when the rolled vertical cross section is etched,
Significantly inhibits etchability. For the above reasons, Cr
The content was determined to be 0.05 to 0.4%.

Zr Zr has a function of forming a compound with Cu by aging treatment and precipitating and strengthening it in the matrix, but if the content is less than 0.03%, the precipitation is insufficient. When Zr is contained in an amount exceeding 0.25%, undissolved Zr remains in the mother phase as a Zr phase even after the solution treatment, resulting in an etching property and a conductive property. Zr content is 0.0
It was determined to be 3 to 0.25%.

Zn Zn is a component that is added as necessary because it has a function of improving the heat-peeling resistance of solder. However, if the content is less than 0.06%, a desired effect by the above-described effect is obtained. On the other hand, when Zn is contained in excess of 2.0%, the electrical conductivity deteriorates, so that the Zn content is 0.06 to 2.0%.
It was decided.

[0012]Ti, Fe, Ni, Sn, In, Mn,
P, Mg and Si Each of these components significantly reduces the conductivity of the alloy.
Has the effect of improving by precipitation strengthening and solid solution strengthening
Therefore, if necessary, one or more kinds of additions are not necessary.
However, if the content is less than 0.01% in total amount
The desired effect of the above-mentioned action is not obtained, while
l. When the content exceeds 0%, the conductivity and processing of the alloy
Remarkably deteriorates the performance. For this reason, single addition or two types
In the above case, Ti, Fe, Ni, Sn, I
The content of n, Mn, P, Mg and Si is 0.01 in total.
１．０1.0%. Subsequently, production of copper alloy of the above composition
The steps will be described.

Solution treatment The solution treatment is to obtain a high-strength material in a later aging treatment and to improve the etching property by dissolving Cr, Zr, Ti and the like in a matrix. The higher the solution treatment temperature, the higher the amount of solid solution in the matrix of Cr, Zr, Ti, etc., the higher the strength after aging and the better the etching property. Therefore, the solution treatment temperature was set to 700 ° C.
With the above, high strength is secured. If the cooling rate during the solution treatment is low, a non-uniform precipitate of Cr having no strengthening action is generated, which causes a decrease in strength and impairs the etching property. Therefore, a high cooling rate is desired.

In the case of the present alloy, the following two methods are available for performing the solution treatment. One of them is a method using a line for continuously performing annealing and water cooling with a plate thickness of preferably about 2 mm or less. In this case, it is necessary to set the annealing temperature to 700 ° C. or higher and water-cool from the annealing temperature for the above-described reason. . Another method is a method of performing solution treatment by performing water cooling after hot rolling. At this time, it was found that the hot rolling end temperature was set at 700 ° C. or higher for the above-described reason, and immediately after that, water cooling was performed at a cooling rate of 100 ° C./min or higher, whereby a decrease in strength could be suppressed. In this method, since cold rolling can be performed immediately after hot rolling, the process is shortened, which is advantageous in terms of manufacturing cost. The hardness after the solution treatment is preferably in the range of Hv 45 to 90.

[0015] In the cold rolling present invention, by performing the cold rolling after the solution treatment,
High strength is obtained by promoting work hardening and precipitation of precipitates in the next aging step. The first cold rolling is 50
%. The reason why the working ratio of the cold rolling is set to 50% or more is that if the working ratio is less than 50%, the above-described effects become insufficient and a desired strength cannot be obtained. The hardness after cold rolling is preferably in the range of Hv 130 to 160.

Aging treatment The aging treatment is carried out in order to improve the strength and conductivity.
-Cr-Zr alloy is necessary. Aging temperature 3
The reason for setting the temperature to 00 to 700 ° C. is that if the temperature is lower than 300 ° C., the aging treatment takes a long time, which is not economical. If the temperature is higher than 700 ° C., Cr and Zr are solid-dissolved, and the strength characteristic of the age hardening type alloy is characteristic. And conductivity cannot be obtained.
The hardness after the aging treatment is preferably in the range of Hv 160 to 200.

Second Cold Rolling In the present invention, cold rolling is performed after the aging treatment, thereby causing work hardening, and also miniaturizing the precipitates formed in the previous aging treatment to further increase the strength. . When the working ratio is set to 30% or more at this time, no increase in strength is observed when the working ratio is less than 30%, and when the working ratio is set to 70% or less, when the working ratio exceeds 70%, bending of the final product is performed. This is because rough skin occurs at the bent portion. The hardness after the second cold rolling is preferably in the range of Hv 180 to 220. Further, the working ratio of the second cold rolling is preferably smaller than that of the first cold rolling and is in the range of 30 to 40%.

[0018] In the stress relief annealing present invention, in order to recover the above processing and and ductility is improved elasticity from the heat treatment conditions, 350-7
Perform strain relief annealing at 00 ° C. Set the annealing temperature at 350 ° C to 7
The reason why the temperature is set to 00 ° C. is that if the temperature is lower than 350 ° C., sufficient resilience and ductility cannot be obtained. If the temperature exceeds 700 ° C., the precipitates are re-dissolved and the strength is significantly reduced.

[0019]

As described above, in the present invention, the solution treatment substantially eliminates the undissolved content of Cr and Zr and enables the first cold rolling at a high working ratio thereafter. Next, by aging treatment and second cold rolling, the aging precipitates are refined and a work-hardened state is obtained, thereby increasing the strength. Finally, work strain is removed by strain relief annealing.

[0020]

EXAMPLES Next, the effects of the present invention will be described more specifically with reference to examples showing particularly preferable composition ranges. First,
The main raw material is electrolytic copper or oxygen-free copper, copper chromium mother alloy, copper zirconium mother alloy, zinc, titanium, nickel,
Using tin, indium, manganese, magnesium and copper phosphorus mother alloys as auxiliary raw materials, copper alloys of various component compositions shown in the tables of FIGS. 1 and 2 are melted in a vacuum or in an Ar atmosphere in a high frequency melting furnace. It was cast into a 30 mm ingot. Next, each of these ingots was subjected to hot working and solution treatment,
The first cold rolling, aging treatment, final cold rolling, and strain relief annealing were sequentially performed under the conditions shown in Tables 1 and 2 to obtain a 0.15 mm plate. The solution treatment was performed according to the methods shown in Tables 1 and 2. Among them, the annealing-water cooling was performed on a plate having a thickness of 1.5 mm, and the heat-pressure cooling was performed on a plate having a thickness of 8 mm. This is the process performed for the hot rolling finishing temperature of
In the case of hot pressure-water cooling, cold rolling was performed immediately after hot rolling.

Then, various test pieces were collected from the obtained plate material and subjected to a material test to evaluate characteristics as electronic device materials. The properties evaluated were strength, elongation, conductivity, etching properties, bending properties, and solder heat-peelability. The strength and elongation were measured by a tensile test, and the conductivity was determined by conductivity (% IACS).

Regarding the “etching”, a liquid temperature of 35 ° C.
A sample having a width of 10 mm and a length of 10 mm was formed in the sample using 45 ° Baume ferric chloride, and the etchability was evaluated by observing the etched surface perpendicular to the rolling direction by SEM. The case where a smooth etched surface was observed was evaluated as ○, and the case where a protrusion of 5 μm or more was observed on the etched surface was evaluated as ×.

Regarding the bending workability, as shown in FIG. 5, a 10 mm test piece was repeatedly bent at 90 ° to one side in a direction perpendicular to the rolling direction at an inner bending radius of 0.4 mm (plate thickness), and until the fracture. The number of times of bending (to be one round trip) was measured. The test was performed with n = 5, and the average was used for evaluation.

The examination of the soldering heat-peelability was carried out after plating the material with 5 μm thick solder (90% Sn-10% Pb),
Hold in a high-temperature bath at 150 ° C for up to 1000 hours.
It was taken out every 00 hours and subjected to one round trip of 90 ° bending to check the start time of solder peeling. 1000
If there was no peeling by the time,
h ".

The results of these investigations are shown in the tables of FIGS.
The following are clear from the results shown in these tables. That is, the alloys 1 to 16 of the present invention are all excellent in strength, conductivity, bendability, and stress relaxation properties, and can be sufficiently evaluated with respect to other properties.

On the other hand, the comparative alloy 17 was inferior in strength because of insufficient Cr content.
Samples Nos. 8 and 19 are inferior in etchability and bendability because the contents of Zr and Cr each exceed the upper limit. next,
The comparative alloy 20 is inferior in conductivity because the Zn content exceeds the upper limit. The strength of the comparative alloy 21 is inferior because the solution treatment temperature is lower than the lower limit value, and the comparative alloy 22 is inferior in strength because the cooling rate during the solution treatment is low. Comparative alloy 22
Is the workability after the solution treatment, and the comparative alloy 24 is inferior in strength because the workability of the final cold rolling is lower than the lower limit. The comparative alloy 24 is an example in which the strength is inferior because the temperature of the strain relief annealing exceeds the upper limit value.

The alloy No. of the embodiment of the present invention was used. 4 Ti
Instead of 0.08% Ni, 0.07% In, 0.
Mn of 0.05, 0.02% of P, 0.05% of Mg,
When the same heat treatment and processing as those of the alloy 4 of the present invention were performed on the alloy to which only 06% of Si was independently added, the same results were obtained.

[0028]

By adopting the manufacturing method of the present invention, it is possible to obtain a copper alloy having good strength, conductivity, etching property and bendability, which greatly contributes to miniaturization and thinning of electronic equipment. And industrially very useful effects.

[Brief description of the drawings]

FIG. 1 is a table showing the composition and production conditions of the alloy of the present invention.

FIG. 2 is a table showing the composition and manufacturing conditions of a comparative alloy.

FIG. 3 is a table showing characteristics of the alloys in Table 1.

FIG. 4 is a chart showing characteristics of the alloys in Table 2.

FIG. 5 is an explanatory diagram of a bending test method.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication // C22F 1/00 630 8719-4K C22F 1/00 630A 8719-4K 630K 661 8719-4K 661A 681 8719-4K 681 682 8719-4K 682 683 8719-4K 683 684 8719-4K 885Z 686 8719-4K 686Z 691 8719-4K 691B 8719-4K 691C 692 8719-4K 692A 694 8719-4K 94

Claims (3)

(57) [Claims] 1. Cr: 0.05 to 0.4% by weight
And Zr: with containing from 0.03 to 0.25%, the balance in the manufacturing method of Cu and electronics high strength high conductivity copper alloy consisting of unavoidable impurities, dissolved therein in a solid state (i) Cr and Zr Cr-burr-like interposition
Solution treatment is performed by any of the following methods to prevent the formation of a product : (a) annealing at a temperature of 700 ° C. or more, and water cooling from the temperature
Continuously performing solution treatment; (b) hot rolling end temperature of 700 ° C. or higher, hot rolling to perform water cooling at 100 ° C. / min or more cooling rate immediately thereafter, (b) working ratio of 50% or more (C) aging treatment at a temperature of 300 to 700 ° C, (d) cold rolling at a workability of 30 to 70%, and (e) strain relief annealing at a temperature of 350 to 700 ° C. By sequentially performing the following steps,
Protrusions of 5μm or more on the etched surface of the hole
Method for producing high strength and high conductivity copper alloy for electronic equipment without etching property . 2. Cr: 0.05 to 0.4 by weight.
%, Zr: 0.03 to 0.25%, Zn: 0.06 to
Together containing 2.0%, in the manufacturing method of the balance electronics high strength high conductivity copper alloy consisting of Cu and unavoidable impurities, (b) by solid solution of Cr and Zr Cr Higebari like intervention
Solution treatment performed by any of the following methods to prevent the formation of products : (a) Solution treatment in which annealing at a temperature of 700 ° C. or more and water cooling from the temperature are continuously performed ; (b) hot rolling end temperature of 700 ° C. or higher, hot rolling to perform water cooling at 100 ° C. / min or more cooling rate immediately thereafter, (b) working ratio of 50% or more of cold rolling, (c) 300 Aging treatment at a temperature of ~ 700 ° C, (d) cold rolling at a working degree of 30-70%, and (e) strain relief annealing at a temperature of 350-700 ° C, thereby sequentially performing rolling. Etchin on plate
Projections of more than 5μm etch ring surface of the open pores in the grayed is
Method for producing high strength and high conductivity copper alloy for electronic equipment without etching property . 3. Cr: 0.05 to 0.4 by weight.
%, Zr: 0.03 to 0.25%, and Zn: 0.06
-2.0%, and further contains Ti, Fe, Ni, Sn, I
at least one of n, Mn, P, Mg and Si: 0.0 in total
A method for producing a high-strength, high-conductivity copper alloy for electronic equipment, which contains 1 to 1.0% and the balance consists of Cu and unavoidable impurities. (A) Cr and Zr and Ti, Fe, Ni, Sn ,
In one or more of In, Mn, P, Mg and Si
What should be done to prevent the formation of balding inclusions in Cr
Solution treatment performed by any of these methods : (a) solution treatment in which annealing at a temperature of 700 ° C. or more and water cooling from that temperature are performed continuously ; (b) hot rolling end temperature is 700 ° C. or more; Immediately thereafter, hot rolling in which water cooling is performed at a cooling rate of 100 ° C./min or more, (b) cold rolling with a working degree of 50% or more, (c) aging treatment at a temperature of 300 to 700 ° C., (d) working degree 30% to 70% cold rolling, and (e) stress relief annealing at a temperature of 350 to 700 ° C., step by sequentially performing consisting etching the rolled plate
Protrusions of 5μm or more on the etched surface of the hole
Method for producing high strength and high conductivity copper alloy for electronic equipment without etching property .