JPH04214821A - Manufacture of ic lead frame material and manufacturing device - Google Patents

Abstract

PURPOSE:To manufacture an IC lead frame material improved in rigidity and toughness and reduced in residual strain by subjecting a long size thin sheet of a stock such as a low thermal expansion alloy to an annealing treatment in such a manner that it is heated while applying tension in a longitudinal direction. CONSTITUTION:The long size thin sheet 9 of an alloy for the IC lead frame is supplied from a coil of a recoiling machine 1 and is traveled, and subjected to the annealing treatment by a heating furnace 5 and a cooling device 6 and is thereafter coiled by a coiling machine 2. At this time, prescribed tension is applied to the above-mentioned thin sheet 9 by a tension device 4, and the part applied with the above-mentioned tension is subjected to the annealing treatment. Furthermore, preferably, a roller leveler 7 is arranged before the above-mentioned heating furnace 5, and the thin sheet 9 is straightened and is thereafter subjected to the annealing treatment in the controlled atmosphere. Moreover, in the case the above-mentioned alloy is an Fe-(40 to 50)Ni low expansion one, it is suitable that the alloy is heated to 500 to 600 deg.C for <=3min at 2 to 10kgf/mm<2> tension and is annealed, and in the case the alloy is a Cu-0.6Fe-0.3 Ti-0.05Mg one, it is suitable that the alloy is heated to 200 to 400 deg.C for <=3min at 1 to 5kgf/mm<2> tension and is annealed.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a lead for IC manufacturing.
The present invention relates to a method and apparatus for manufacturing a dome material.
The present invention provides a material with improved rigidity and toughness and less distortion after processing.

0002

2. Description of the Related Art Thin plates of alloys with a low coefficient of thermal expansion, typically Fe-42Ni, are used as lead frame materials for manufacturing various ICs. As ICs become smaller and more dense, lead frame materials are required to be thinner and have higher strength, and it is necessary to further improve their rigidity and toughness. Along with that,
It is also necessary to reduce residual stress as much as possible so that distortion does not appear after processing such as punching.

[0003] The inventors noticed that a method called "tension annealing", that is, an annealing treatment in which the material is heated under tension, is effective in improving the spring limit value of spring materials. We conducted experiments with the hope that this would be useful in improving the physical properties of lead frame materials. As a result, we learned that it is possible to improve rigidity and toughness and reduce residual stress.

Furthermore, the inventors thought that a roller leveler, which is used for flattening long thin plates, would also be effective in removing distortion from IC lead frame materials.
As a result of the experiment, prior to the above-mentioned tension annealing,
It has been found that correction using this roller leveler is effective.

[0005]

[Problems to be Solved by the Invention] An object of the present invention is to utilize the above knowledge to develop a lead frame that meets recent demands.
An object of the present invention is to provide a method and apparatus for manufacturing an IC lead frame alloy material, ie, an alloy material typified by a low-expansion alloy, which has improved rigidity and toughness and reduced residual strain.

[0006]

[Means for Solving the Problems] The method for manufacturing an IC lead frame material of the present invention is basically as shown in FIG.
This process consists of applying annealing to a long thin plate of alloy for C-lead frames while applying tension in the longitudinal direction and heating the part to which the tension is applied.

A preferred embodiment of the method for manufacturing an IC lead frame material of the present invention includes, in addition to the above basic operations, a method for manufacturing an IC lead frame material.
First, we perform correction using a roller leveler. That is,
As shown in Figure 2, a long thin plate of IC lead frame alloy is straightened using a non-driven roller leveler, and then tension is applied in the longitudinal direction. It consists of applying an annealing treatment to heat the added part.

The Fe-42Ni low expansion alloy mentioned above is typical as an alloy for IC lead frames, and the suitable annealing conditions in this case are 500 Kgf/mm2 tension and 500 Kgf/mm2 tension. ~600°C for a period of up to 3 minutes.

In addition to this alloy, the present invention can also be applied to Cu-based alloys. As an example, Cu-0.6Fe-0.
3Ti-0.05Mg alloy is mentioned. Appropriate annealing conditions for this alloy are a tension of 1 to 5 Kgf/mm2 and heating at 200 to 400°C for up to 3 minutes.
There are many other types of Cu-based IC lead frame alloys, but the optimal annealing conditions for each can be found by conducting some experiments as necessary.

The IC lead frame manufacturing apparatus of the present invention includes:
Basically, as shown in Fig. 1, means (1 and 2) for unwinding a thin plate coil of IC lead frame alloy from one side and winding it up on the other side, and a means (1 and 2) provided between them under a controlled atmosphere. Annealing means (5 and 6) for heating and cooling the sheet
, and means (4) for applying a predetermined tension to the sheet during annealing.

In a preferred embodiment of the apparatus of the present invention, as shown in FIG. 2, in the apparatus of FIG. A leveler (7) is added.

0012

[Operation] In Fig. 1, the long lead frame material (9)
is unwound from the unwinding machine (1) and then taken up by the winding machine (2).
Wind it up with the bridle roll (3A) and (3
B) The tension is applied by the difference in feed rate. The strength of the tension is measured by a tension detection device (4), and the rotational speed of the bridle roll is adjusted so that it becomes an appropriate value. Reference numeral (5) is a heating furnace that heats the thin plate to a predetermined temperature. During heating, it is preferable to control the atmosphere and perform annealing under non-oxidizing conditions (for example, using a mixed gas of N2+H2). The heated IC lead frame material is cooled at an appropriate rate (usually 1 to 10° C./second) in a controlled atmosphere to avoid oxidation or deformation before being exposed to the outside. Reference numeral (6) in FIG. 1 is a cooling device provided for this purpose.

Fe-4 as an alloy for IC lead frames
Explaining the annealing conditions when using a 2Ni low expansion alloy, the effect of tension annealing is weak unless the applied tension is 2 Kgf/mm2 or more;
A tension exceeding Kgf/mm2 will actually reduce the spring limit value. Generally, 3Kgf/mm2 or more, 7K
gf/mm2 or less is suitable. The higher the heating temperature, the shorter the time required, and the higher the productivity of continuous processing, but high temperature and long processing will lead to a decrease in the spring limit value. Select appropriate conditions from the range. Typically, 600℃ x 1~
2 minutes is appropriate.

The operation shown in FIG. 2 is performed using the bridle roll (3A).
The lead frame material that has passed through the
After passing through the leveler (7), tension annealing is performed in the same manner as described above. As shown in Fig. 3, the roller leveler (7) consists of a plurality of non-driven (in this example, five) rollers that rotate freely, and the pushing amount is The sides are large and become smaller toward the exit side, and the final stage is arranged so that the overlap is zero. While passing through these rollers, the leadframe material undergoes bending in alternating directions with progressively lower stresses, thereby reducing strain.

[0015]

Example 1 A thin plate of Fe-42Ni alloy with a thickness of 0.25 mm was heated at 500 to 660° C. for 1 to 5 minutes, and the spring limit value was measured. The results are as follows, and heating at 600° C. for 1 minute gave the best results.

[0016]

[Table 1]

Next, for the same material, the heating conditions were changed to 60
Keep the tension constant at 0°C for 1 minute (or 2 minutes) and set the tension to 0.
The spring limit value, Young's modulus and elongation were measured by varying the range from 15 kgf/mm2 to 15 kgf/mm2. The results are shown in Figure 4 (spring limit value), Figure 5 (Young's modulus), and Figure 6 (
As shown in the graph of (elongation). From these graphs, for Young's modulus and elongation, the tension is 3Kgf/mm.
Although a substantially constant value can be obtained at 2 or more, it can be seen that a range of 3 to 7 Kgf/mm2 is appropriate for the spring limit value.

Similarly, for samples subjected to heat treatment at 600°C for 1 minute (or 2 minutes) under various tensions,
Warpage of thin sheet material in the longitudinal direction (“crossbow” or “
(referred to as "C warp") and in the width direction ("curl" or "L
The warpage (referred to as "warpage") was measured. The results are as shown in FIG. 7 (crossball) and FIG. 8 (curl). They are within the targeted 20 μm (crossbow) and 10 mm/1000 mm (curl), respectively.

Furthermore, 600 showed the best results.
The residual stress in the longitudinal direction and the width direction was measured for the sample which was heated at ℃ for 1 minute under a tension of 5 Kgf/mm2. The results are shown in Figure 9 (longitudinal direction) and Figure 1
0 (width direction), and the target residual stress value of ±10 Kgf/mm2 or less was sufficiently achieved in both directions.

[0020]

Example 2 A roller leveler was added to the apparatus used in Example 1. The roller leveler used was 5 rollers with a diameter of 30 mm and a barrel length of 100 mm as shown in Figure 3.
It is arranged as follows, and the pushing amount between the first roller (71) and the second roller (72) is 2.0 mm at maximum.
And the third roller (73), the fourth roller (74)
Then, the pushing amount gradually decreases, and the overlap amount between the fourth roller and the fifth roller (75) becomes zero.

[0021] Using this device, a thin plate of Fe-42Ni alloy with a thickness of 0.25 mm was subjected to a heating process of 1 to 60.5 kgf.
After heating at 600°C for 2 minutes while applying a tension in the range of /mm2, cooling was performed at an average cooling rate of 5°C/sec.

[0022] Regarding the material after treatment, warpage in the longitudinal direction (
Crossball) and warp (curl) in the width direction were measured. A comparison was made between the case of only annealing under tension (TA) and the case of adding straightening using a roller leveler (R.L), and the results shown in Figs. 11 and 12 were obtained. Ta. The measurement results of residual stress are as shown in FIG. 13.

[0023]

Effects of the Invention The lead frame material produced by the method of the present invention has improved Young's modulus and spring limit value, and increased rigidity and toughness, making it possible to make lead frames thinner and smaller. Able to meet demands. In addition, the residual stress is reduced, and the shape is accurate and there is little distortion even after punching.
High precision lead frames can be made. Improvement in elongation brings about improvement in workability and facilitates thinning and increasing the number of pins.

The device of the present invention can be constructed from a combination of common parts, is easy to assemble and operate, and
Distortion of the IC lead frame material can be effectively removed.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of an apparatus for explaining a basic aspect of the method for manufacturing an IC lead frame material of the present invention.

FIG. 2 is a conceptual diagram of an apparatus similar to FIG. 1 for explaining a preferred embodiment of the method for manufacturing an IC lead frame material of the present invention.

[Fig. 3] An enlarged view of a part of Fig. 2.

FIG. 4 is a graph showing the relationship between tension and spring limit value when tension is applied to an alloy for IC lead frames and heated.

FIG. 5 is a graph similar to FIG. 4, showing the relationship between tension and Young's modulus.

FIG. 6 is a graph similar to FIG. 4, showing the relationship between tension and elongation.

FIG. 7 is a graph showing the relationship between tension and warpage in the longitudinal direction when an alloy for IC lead frames is heated under tension.

8 is a graph similar to FIG. 7, showing the relationship between tension and warpage in the width direction.

FIG. 9 is a graph showing the residual stress in the longitudinal direction of the IC lead frame material manufactured by the basic aspect of the manufacturing method of the present invention.

FIG. 10 is a graph similar to FIG. 9, showing residual stress in the width direction.

[Figure 11] Shows the relationship between tension and warpage in the longitudinal direction when the alloy for IC lead frames is heated under tension and when straightened using a roller leveler prior to heating. graph.

FIG. 12 is a graph similar to FIG. 11, showing the relationship between tension and warpage in the width direction.

FIG. 13 is a graph showing residual stress in the longitudinal direction of an IC lead frame material manufactured by a preferred embodiment of the manufacturing method of the present invention.

[Explanation of symbols]

1 Rewind machine 2. Winding machine 3A, 3B Bridle roll 4 Tension detection device 5 Heating furnace 6 Cooling device 7 Roller leveler 9 Fe-42Ni alloy thin plate

Claims (6)

[Claims] [Claim 1] An IC comprising an IC lead frame in which an elongated thin plate of an alloy is subjected to an annealing treatment in which tension is applied in the longitudinal direction and the part to which the tension is applied is heated.
A method for manufacturing lead frame material. [Claim 2] After straightening a long thin plate of alloy for IC lead frames using a non-driven roller leveler, while applying tension in the longitudinal direction, the tensioned portion is A method for manufacturing an IC lead frame material, which comprises performing a heating annealing treatment. [Claim 3] F as an alloy for IC lead frames.
e-(40-50) Ni low expansion alloy is used, 2-10
500-600℃ while applying tension of Kgf/mm2
3. The method of manufacturing an IC lead frame material according to claim 1, wherein the annealing process is performed under annealing conditions of heating for up to 3 minutes. [Claim 4] C as an alloy for IC lead frames.
Using u-0.6Fe-0.3Ti-0.05Mg alloy, 200
3. The method for manufacturing an IC lead frame material according to claim 1, wherein the annealing process is performed by heating to ~400[deg.] C. for 3 minutes or less. 5. A means for unwinding a coil of a thin plate of an alloy for an IC lead frame from one side and winding it on the other, an annealing means provided between the coils for heating or heating and pressurizing the thin plate in a controlled atmosphere, and cooling the thin plate; , an IC lead comprising means for applying a predetermined tension to the thin plate during annealing.
Manufacturing equipment for dome materials. 6. The manufacturing apparatus according to claim 5, wherein a roller leveler is added before the annealing means for the thin plate of alloy for IC lead frames.