JP3042273B2 - Method for producing Fe-Ni-based alloy thin plate for IC lead frame with excellent rust resistance - 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 producing an Fe--Ni-based alloy sheet used as an IC lead frame material.

[0002]

2. Description of the Related Art Fe-Ni alloys containing 26 to 52% of Ni have been widely used as materials for IC lead frames because of their low thermal expansion coefficients in the temperature range from room temperature to 300 ° C.

However, the above-mentioned materials may rust is likely to occur not rusting resistance sufficiently in the air, for example if Fe-N
Rust often occurs during the manufacturing process of the i-based alloy band and during the manufacture of the above-described IC lead frame member using the Fe-Ni-based alloy band as a material, and improvement of rust resistance is strongly desired. Fe
JP-A-60-2 as a method for improving the rust resistance of Ni-Ni alloys
No. 1331 discloses a technique for improving the corrosion resistance of a system alloy by adding Cr and Co.

[0004]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
Techniques to 60-21331 JP been disclosed, Cr as improved methods rusting resistance, Ri Contact depends only on the adjustment of the Fe-Ni based alloy components will leave the addition of Co, F e-Ni based alloy No mention is made of an oxide film having an effect on the rust resistance of the steel sheet, and neither rolling conditions nor heat treatment conditions which greatly affect the state of formation of the oxide film are described. It also mentions the deterioration of plating properties, which is an important property for Fe-Ni alloys for IC lead frames , which is expected to be inevitably caused by forming an oxide film and improving rust resistance. Absent.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an Fe-Ni type for an IC lead frame which does not easily generate rust without deteriorating plating properties. An object of the present invention is to provide a method for manufacturing an alloy thin plate.

[0006]

The first method of manufacturing an Fe-Ni-based alloy thin plate for an IC lead frame having excellent rust resistance according to the present invention is as follows: Wt%: Ni: 38 to 52%, Cr : 0.05 to 3.0%
Or less, Si: 0.10% or less, Al: 0.05% or less, C: 0.009% or less, Mn:
0.40% or less, with the balance being Fe and unavoidable impurities.
After rolling the Fe- Ni-based alloy strip at a cold rolling rate of 15-29%,
H ₂ : _{2 to 10} vol%, O ₂ : 0.01 vol% or less, the balance is an inert gas and the dew point is in the atmosphere of -20 to -60 ° C, annealing temperature
The stress relief annealing is performed under the conditions of 450 to 600 ° C and a holding time of 0.5 to 300 seconds.

Further, a second method of manufacturing an Fe—Ni-based alloy thin plate for an IC lead frame having excellent rust resistance according to the present invention is as follows.
Ni: 38 to 52%, Cr : 0.05 to 3.0% or less, Co: 1.0% or less, Si: 0.10% or less, Al: 0.05% or less, C: 0.009% or less, Mn: 0.
Contains up to 40%, with the balance being Fe and unavoidable impurities
Cold rolling and stress relief annealing are performed on the Fe - Ni alloy strip under the same conditions as in the first production method.

Further, the third method of producing a thin Fe-Ni-based alloy sheet for an IC lead frame according to the present invention, which is excellent in rust resistance, is as follows: Wt%: Ni: 26 to 38%, Cr : over 0.05 3 .0%, Co:
1.0% to 20%, Si: 0.10% or less, Al: 0.05% or less, C:
0.009% or less, Mn: 0.40% or less, with the balance Fe and
Cold rolling and stress relieving annealing are performed on the Fe - Ni-based alloy strip made of the impurity by the same conditions as in the first manufacturing method.

[0009]

The reasons for limiting the chemical components in the first method for producing an Fe-Ni-based alloy thin plate for an IC lead frame having excellent rust resistance according to the present invention will be described below. The first excellent rust-resistant Fe-Ni-based alloy thin plate for an IC lead frame of the present invention, when used as an IC lead frame, is required to maintain the balance of thermal expansion with semiconductor elements, glass, ceramics, and the like. , Ni content must be 38-52%. Therefore,
The range of Ni content was 38-52%.

[0010] Si is used as a deoxidizing element during melting of the alloy, when it exceeds 0.10%, unevenness of Si to Fe-Ni alloy strip surface during stress relief annealing of Fe-Ni alloy strip Even if a suitable oxide film is formed and the manufacturing method described below is optimized, excellent plating properties as a material for an IC lead frame cannot be ensured. Therefore, the upper limit of Si is set to 0.10%.

C is an element that forms Cr carbide in the present alloy and deteriorates rust resistance. Thus, as much as possible it is desirable little, if C amount is hereinafter 0.00 9%, by employing a manufacturing method described later, since the rusting resistance intended in the present invention is obtained, the upper limit of C is 0.009% And

Mn is a harmful element for ensuring the surface treatment properties of the alloy thin sheet of the present invention. Therefore, it is desirable that the amount is as small as possible, but if the amount of Mn is 0.40% or less, it is intended in the present invention by adopting a manufacturing method described later.
The upper limit of Mn was set to 0.40% because the plating property as an IC lead frame material can be secured.

[0013] Cr is, Ri element der to improve the mechanical properties,
In order to exhibit this effect it is desirable to free Yes at more than 0.05%. However, if the addition amount exceeds 3%, the average coefficient of thermal expansion becomes too large, so the upper limit of Cr was set to 3%.

Next, the reason why the cold rolling rate at the time of cold rolling is set to 15 to 29% will be described. This cold rolling is performed in order to obtain a thin plate having a desired shape, but at the same time, aims at improving rust resistance while ensuring plating property. To get these properties,
Even at the optimum stress relief annealing under cold rolling rate is described later is less than 15%, very thin dense oxide film of thickness less than 20Å to improve the rusting resistance of the surface treatability with ensuring of the alloy sheet is formed Therefore, sufficient rust resistance cannot be obtained. On the other hand, the cold rolling rate was 29
%, The oxide film becomes too thick even when optimal stress relief annealing is performed, and the surface treatment property of the present alloy cannot be ensured. Therefore, the cold rolling rate was set to 15-29%.

Next, as conditions for the stress relief annealing, the annealing temperature is 450 to 600 ° C., the holding time is 0.5 to 300 seconds, the dew point of the atmosphere in the annealing furnace is -20 to -60 ° C., and the composition of the atmosphere is H _2. : 2
The reason why 1010 vol%, O ₂ 0.01 vol%, and the rest are inert gas will be described.

The stress relief annealing conditions are as follows: annealing temperature is less than 450 ° C., holding time is less than 0.5 seconds, and the dew point of the atmosphere in the annealing furnace is
Less than -60 ° C., in the case where H ₂ is in either condition of exceeding 10 vol%, even other conditions were optimal conditions for stress relief annealing the alloy, the surface of the alloy An extremely thin dense oxide film having a thickness of 20 mm or less that can improve rust resistance while ensuring processability is not formed, and excellent rust resistance cannot be obtained.

Further, the conditions for the stress relief annealing are as follows:
° C. greater than the retention time is 300 Byokoe, the dew point of the atmosphere exceeds -20 ° C. in the annealing furnace, H ₂ is less than 2 vol%, when O ₂ is in either condition of exceeding 0.01 vol%, the other Even if the conditions are optimal for stress-relief annealing of the present alloy, the oxide film described above becomes too thick, and the surface treatment properties of the present alloy cannot be ensured.

Next, in the second method for producing an Fe-Ni-based alloy thin plate for an IC lead frame having excellent rust resistance according to the present invention, the chemical components are limited for the following reasons. The chemical components other than Co are the same as those described in the first method for producing a Fe—Ni-based alloy thin plate for an IC lead frame having excellent rust resistance. Co has the same effect as Ni, and is used as a nickel source such as ferronickel and electrolytic nickel.
About 1% or less is included.

The range of the cold-rolling rate and the annealing conditions of the stress relief annealing are also the same as those described in the first method for producing an Fe-Ni-based alloy sheet for an IC lead frame having excellent rust resistance. Things.

Next, in the third method for producing an Fe-Ni-based alloy thin plate for an IC lead frame having excellent rust resistance according to the present invention, the chemical components are limited for the following reasons. The chemical components other than Co are the same as those described in the first method for producing a Fe—Ni-based alloy thin plate for an IC lead frame having excellent rust resistance. By adding Co over 1% to 20% and Ni in the range of 26-33%, more excellent properties can be obtained as a material for an IC lead frame.
Of course, Co contained in a nickel source such as ferronickel or electrolytic nickel can also be used for this Co.

The range of the cold-rolling rate and the annealing conditions for the stress relief annealing are also the same as those described in the first method for producing a Fe—Ni-based alloy sheet for an IC lead frame having excellent rust resistance. Things.

[0022]

An embodiment of the present invention will be described. By ladle refining, as shown in Table 1, Fe-Ni based alloy that have a chemical composition
B was melted and made into a slab by ingot or continuous casting. The ingot was made into a slab by slab rolling.

[0023]

[Table 1]

The surface defects of these slabs were removed, and thin hot-rolled coils were obtained from the slabs by hot rolling. Using this hot rolled coil as a material, cold primary rolling-primary annealing-finishing cold rolling
-Stress relief annealing was performed to obtain test materials (No. 1 to No. 8) of Fe-Ni-based alloy thin plates having a thickness of 0.15 mm. Table 2 shows the conditions of the finish cold rolling rate (CR%) and stress relief annealing of each test material.

[0025]

[Table 2]

Further, these test materials are described in JIS Z 23
The salt spray test specified in 71 performed between 10:00 and point銹発raw frequency
(Pieces / 100 cm ² ) were investigated. Also, after degreased and pickled these test materials, a 1-μm-thick Ag plating was applied and heated in air at 450 ° C for 5 minutes. It was observed at a magnification of 50 times. Table 3 shows the results of these surveys.

[0027]

[Table 3]

As is evident from the results shown in Tables 2 and 3, the test material No. 1 manufactured with the component composition within the scope of the present invention and the finish cold rolling rate and the stress relief annealing conditions within the scope of the present invention.
The test materials of Nos. 6 to No. 8 have a low frequency of spot rusting and have excellent rust resistance, and also exhibit excellent Ag plating properties as intended in the present invention.

[0029] In contrast, although the chemical composition is within the scope of the invention, the test material No.1 is to give a upper finish cold rolling rate is super, trial <br/> test material No. 3 with an upper limit of the annealing time the exceeded, because the test material No. 5 is beyond the O ₂ is the upper limit of the atmosphere, point銹発students frequency of 5
It is less than 100 pieces / 100 cm ² , but the Ag plating property is inferior to the examples of the present invention.

[0030] hand, test material No. 2 is Ri annealing temperature down <br/> times the lower limit, since tests member No. 4 is greater than of H ₂ is the upper limit of the atmosphere, Ag plating property the Test materials No.1, No.3 and No.5
It is superior to that of
² or more, the test materials of the present invention examples No. 6 to No. 8
Inferior to those of

[0031]

According to the present invention, the rust resistance of the Fe—Ni-based alloy thin plate for an IC lead frame can be improved without impairing the Ag plating property.

Continuation of the front page (51) Int.Cl. ⁷ identification code FI C22C 38/52 C22C 38/52 (56) References JP-A-63-118016 (JP, A) JP-A-63-259027 (JP, A) JP-A-5-171357 (JP, A) JP-A-3-202446 (JP, A) JP-A-4-221024 (JP, A) JP-A-6-73452 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C21D 9/46-9/48 H01L 23/48 C22C 19/05 C22C 38/00-38/60

Claims (3)

(57) [Claims] (1) Wt%, Ni: 38 to 52%, Cr : over 0.05 to 3 .
0% or less, Si: 0.10% or less, Al: 0.05% or less, C: 0.009% or less,
Mn: 0.40% or less , the balance being Fe and unavoidable impurities
The Ranaru Fe -Ni alloy strip, after cold-rolled and cold rolling ratio at _{15~29%, H 2: 2 ~10vol} %, O 2: 0.01vol% or less, the balance being not <br/> inert gas An IC lead frame with excellent rust resistance characterized in that stress relief annealing is performed in an atmosphere with a dew point of -20 to -60 ° C at an annealing temperature of 450 to 600 ° C and a holding time of 0.5 to 300 seconds. Of manufacturing Fe-Ni alloy thin sheet for use. (2) In Wt%, Ni: 38 to 52%, Cr : more than 0.05 to 3 .
0%, Co: 1.0% or less, Si: 0.10% or less, Al: 0.05% or less, C:
0.009% or less, Mn: 0.40% or less, with the balance Fe and
A method for producing a thin Fe-Ni-based alloy sheet having excellent rust resistance, comprising subjecting a Fe - Ni-based alloy strip made of impurities to cold rolling and stress relief annealing under the conditions described in claim 1. (3) In Wt%, Ni: 26-38%, Cr : more than 0.05-3 .
0%, Co: more than 1.0% to 20%, Si: 0.10% or less, Al: 0.05%
Hereinafter, C: 0.009% or less, Mn: 0.40% or less , the balance Fe
Claim 1 to the Fe - Ni-based alloy band consisting of
A method for producing an Fe-Ni-based alloy sheet having excellent rust resistance, comprising performing cold rolling and stress relief annealing under the conditions described in (1).