JPS62224484A - Method for providing clad layer of dissimilar metal part at fixed intervals on strip like metal sheet - Google Patents

Abstract

PURPOSE:To improve the dimensional and positional accuracies of a part clad layer by performing a temporary cladding by overlapping a strip like metal foil on a strip like metal sheet and by performing a main cladding of temporary clad cut piece by removing the metal foil nonclad cut piece excepting a square metal coil temporary clad cut piece. CONSTITUTION:The pressing part is subjected to a temporary cladding by pressing in the right angles direction at fixed intervals by the press 5 equipping the upper die 6 and lower die 7 by overlapping a strip shaped metal foil 2 on one face of a strip shaped metal sheet 1. The metal foil temporary clad cut piece 2B which is arranged at the prescribed intervals on the strip like metal sheet 1 is then left over by removing the metal foil nonclad cut piece 2A excepting an about square metal foil temporary clad cut piece 2B, after cutting the strip like metal foil 2 in the width direction so as to form the cutting plane line 4 passing the before and behind both side edges of all temporary clad zone. The metal foil cut piece 2B is then subjected to a main cladding to the metal sheet 1 by passing through the rolls 8, 9 for secondary cladding in a pair of the upper and lower. A clad layer 2S is finally provided at fixed intervals on the metal sheet 1 with the diffused joining of the metal sheet 1 and metal foil cut piece 2B by heating it in a vacuum.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for providing dissimilar metal partial cladding layers at regular intervals on a strip-shaped metal sheet, and relates to a method for providing a strip-shaped metal sheet with dissimilar metal partial cladding layers at regular intervals. The metal sheet is used, for example, as a lead frame for mounting an IC (heat collecting circuit).

Conventional technology Conventionally, a strip metal sheet with an aluminum partial cladding layer used as a lead frame, for example,
For example, the method described in Japanese Patent Application Laid-open No. 59-44774 is known, but according to the conventional method, a pair of pressure-welding rolls is used to press a band-shaped aluminum foil in which i-holes are drilled at predetermined intervals onto a band-shaped metal sheet. Since the aluminum foil was used for temporary pressure bonding, wrinkles were generated in the width direction of the aluminum foil, and there was a problem in that the dimensional and positional accuracy of the partial cladding layer made of the aluminum foil could not be ensured. Further, according to the conventional method, a partial cladding layer of aluminum foil is formed on both side edges of the metal sheet, so there is a problem that it cannot be applied to a lead frame material of a package having bins on all sides.

Purpose of the Invention An object of the present invention is to solve the above-mentioned problem, and to solve the problem that, when a predetermined portion of a band-shaped metal foil made of a different material is temporarily pressed onto a band-shaped bottom sheet, wrinkles occur in the width direction of the band-shaped metal foil. Therefore, it is possible to ensure sufficient dimensional and positional accuracy of the partial cladding layer made of metal foil, and the partial cladding layer is not formed on both side edges of the metal sheet, so that it is possible to have bins on all sides. The object of the present invention is to provide a method for manufacturing a metal sheet having a partial cladding layer of dissimilar metals, which can also be applied to a lead frame material of a package.

Structure of the Invention In order to achieve the above-mentioned object, the present invention first provides a method according to a first aspect of the present invention, in which a band-shaped metal sheet and a band-shaped metal foil of a predetermined width made of a different material are prepared, A band-shaped metal foil is superimposed on at least one side of the band-shaped metal sheet, and the band-shaped metal foil is pressed in a direction perpendicular to the metal sheet at regular intervals to temporarily press these pressed parts to the band-shaped metal sheet, and then After cutting the band-shaped metal foil in the width direction so as to form a cutting line passing through both front and rear edges of all the temporary press-welded parts, peel off and remove the non-pressure-welded metal foil pieces other than the approximately rectangular metal foil temporary press-welded pieces. The metal foil non-pressure-welded fragments lined up at predetermined intervals remain on the band-shaped metal sheet, and then the metal sheet with the metal foil temporary-pressure-welded fragments is passed between the rolls for secondary pressure welding, and as a result, the metal foil temporary The gist of this invention is a method for providing partial cladding layers of dissimilar metals at regular intervals on a band-shaped metal sheet, which is characterized in that the press-welded fragments are brought into full pressure contact with the band-shaped metal sheet.

Next, in the method of the second aspect of the present invention, a band-shaped metal sheet and a band-shaped metal foil made of a different material are prepared, and holes having a required size are formed in the band-shaped metal foil by punching. At least one row of metal foil is formed at predetermined intervals in the length direction of the metal foil, the strip metal foil is overlapped on at least one side of the strip metal sheet, and the intermediate portion of a predetermined width formed between the holes of the metal foil is covered with the metal sheet. These pressed parts are temporarily pressed against the band-shaped metal sheet by pressing in a direction perpendicular to the hole, and then the band-shaped gold PAM is formed into an insulating line that passes through both the left and right edges of the hole or slightly inside the left and right edges of the hole. The strip-shaped metal foil is cut in the length direction as shown in FIG. The metal foil temporarily pressed pieces lined up at predetermined intervals remain on the metal sheet, and then the metal sheet having the metal foil temporarily pressed pieces is passed between secondary press rolls, and as a result, the metal foil temporarily pressed pieces are formed into a band-like shape. The gist of the present invention is a method of providing dissimilar metal partial cladding layers at regular intervals on a band-shaped metal sheet, which is characterized by bringing the metal sheet into full pressure contact with the metal sheet.

In the above, the band-shaped metal sheet is, for example, 427
0i (Fe-Ni alloy), other iron alloys, copper alloys such as phosphor bronze, aluminum alloys, etc. are used. Further, as the band-shaped metal foil, foil materials such as high-purity aluminum, aluminum alloy, copper, silver, lead, tin, and gold with a purity of 99 wt % or more are used. The metal sheet is provided with a dissimilar metal partial cladding layer on one or both sides thereof.

In the first invention, a band-shaped metal foil having a predetermined width of, for example, 5 mm is prepared. Temporary pressure bonding of a band-shaped metal sheet and a band-shaped metal foil is carried out by overlapping them and pressing the band-shaped metal foil in a direction perpendicular to the metal sheet at regular intervals using a device such as a press, so that these pressed areas are bonded to the metal sheet. The rolling reduction ratio is usually 5 to 1.
Preferably it is 5%.

After temporary pressure welding, the strip-shaped metal foil is cut in the width direction so as to form a cutting line that passes through both the front and back sides of all the temporary pressure welded parts, and the metal foil is temporarily welded into a substantially rectangular shape using wind pressure of dry air or nitrogen gas. By peeling off and removing the metal foil non-pressure-contacted fragments other than the fragments, temporarily press-contacted metal foil fragments arranged at predetermined intervals are left on the band-shaped metal sheet.

Here, since the gold RIF4 foil is in the form of a band with a predetermined width, when stacking the band-shaped metal foil on the band-shaped metal sheet, the band-shaped metal foil will not be torn even if sufficient tension is applied, and the metal The position of the foil pieces is extremely accurate, and the strip metal foil is sharply cut along the required cutting line to a depth corresponding to the thickness of the metal foil. The temporarily pressed pieces have extremely high dimensional accuracy and are arranged at a constant pitch.

After peeling off and removing the non-pressure welded pieces of metal foil, the belt-shaped metal sheet having the temporarily press-welded gold foil pieces is guided to a secondary pressure welding roll with a smooth surface and rolled to perform the main pressure welding. Preferably, the ratio is 5 to 20%. After the main pressure welding, depending on the case, plate thickness adjustment rolling is performed at a reduction rate of 10% or less, but this may of course be omitted.

After the secondary pressure bonding, the band-shaped metal sheet having the metal foil pieces is usually heated in a vacuum or an inert gas atmosphere to diffusion bond the metal sheet and the metal foil pieces to improve the adhesion between them.

Diffusion bonding after secondary pressure welding is performed in a vacuum or inert gas atmosphere to prevent oxidation of the metal sheets and metal foil pieces, but in the former case, the degree of vacuum is 10-3 to 10-1. 'Torr is preferable. In the latter case, it is carried out in an atmosphere of a chemically inert gas such as nitrogen gas or argon gas. In either case, the heat treatment is performed at a temperature of about 300 to 450°C for 30 minutes.
This is carried out for ~60 minutes to ensure sufficient interdiffusion of the strip metal sheet and the metal foil pieces.

On the other hand, in the second aspect of the invention, the band-shaped metal foil has a width 2 to 10 mm narrower than the width of the normal metal sheet. At least one row of holes having a required size are formed in the strip-shaped metal foil at predetermined intervals in the length direction of the strip-shaped metal foil by punching. Temporary pressure bonding of the band-shaped metal sheet and the band-shaped metal foil is carried out by overlapping them and pressing the intermediate part of a predetermined width formed between the holes of the band-shaped base a foil in a direction perpendicular to the metal sheet. The pressing portion is temporarily pressed against the band-shaped metal sheet, and the rolling reduction ratio at this time is preferably 5 to 15%.

Immediately after the temporary pressure bonding, a cutting line is inserted into the band-shaped metal foil, and the band-shaped metal foil piece is peeled off while being wound into a coil.

Here, the band-shaped metal foil is punched with a hole having a predetermined size at a certain bit, and is sharply cut by a cutting line that passes along both the left and right edges of the hole or slightly inside the left and right edges. The flakes of metal foil formed after peeling off the metal foil pieces have extremely high dimensional accuracy and are arranged at a constant pitch.

The main pressure welding is carried out by introducing the band-shaped gold layer sheet to a secondary pressure roll and rolling it, and the reduction ratio at this time is preferably 5 to 20%. After the main pressure welding, depending on the case, plate thickness adjustment rolling is performed at a reduction rate of 10% or less, but this may of course be omitted.

After secondary pressure welding, the strip metal sheet 1 usually has gold a-foil pieces.
- is heated in a vacuum or an inert gas atmosphere to diffusion bond the metal sheet and the metal foil piece to improve the adhesion between them.

Example Next, embodiments of the present invention will be described based on the drawings.

Embodiment 1 In FIGS. 1 to 4 showing an embodiment of the first invention of the present invention, first a band-shaped metal sheet (1) made of 4270I and a 99.99wt% pure aluminum made of a different material. A band-shaped metal foil (2) made of foil was prepared. Here, the thickness of the band-shaped metal sheet (1) is 0.32 mm.
The strip metal foil (2) has a thickness of 10tII11 and a width of 5 mm.

Next, a strip metal ff1 is placed on one side of the strip metal sheet (1).
(2) are overlapped, and the strip metal foil (2) is pressed perpendicularly to the metal sheet (1) at regular intervals by a press (5) equipped with an upper die (6) and a lower die (7). Then, these pressed parts were temporarily pressed against the band-shaped metal sheet (1) (
Figures 1 and 2). The rolling reduction rate at this time was 8%.

After the temporary pressure welding, the band-shaped metal foil (2) was cut in the width direction so as to form a cutting line (4) passing through both front and rear edges of all the temporary pressure welded parts, and then subjected to a nitrogen gas wind pressure of 2 m/sec. By peeling off and removing the metal foil non-pressure-bonded pieces (2A) other than the approximately rectangular metal foil temporary-pressure-bond pieces (2B), the metal foil temporary-pressure-bond pieces are arranged at predetermined intervals on the band-shaped metal sheet (1). (2B) was allowed to remain.

Next, a metal sheet (
1) was passed between a pair of upper and lower secondary pressure welding rolls (8) and (9) to bring the metal foil fragment (2B) to the band-shaped metal sheet (1) in a cold manner (Fig. 3). . At this time, the rolling reduction rate by the secondary pressure welding roll was set to 16.7%, and the final thickness of the band-shaped metal sheet (1) was 0.2511.
111, the size of the metal foil pieces (2B) was 5 mm square, and the pitch between the metal foil pieces (2B) was 5 mm.

Finally, the band-shaped metal sheet (1) having the metal foil pieces (2B) which have been fully pressure-welded is placed in a vacuum (10-' Torr).
), heated at 450°C for 30 minutes to form metal sheet 1-(1
) and metal foil pieces (2B) are diffusion bonded, thereby providing aluminum partial cladding (2S) at regular intervals on the band-shaped metal sheet (1) (Fig. 4).

The band-shaped metal sheet (1) having the aluminum partial cladding layer (2S) obtained by the above method had very precise dimensional accuracy and could be advantageously used, for example, as a lead frame for mounting an IC.

Embodiment 2 FIGS. 5, 6, 3, and 4 show the method of the second invention.

First, a band-shaped metal foil (2) and a band-shaped metal sheet (1) made of the same material as in the first embodiment were prepared. Here, the width of the band-shaped metal sheet (1) is the same as in Example 1 <25
mm, but the width of the band-shaped metal foil (2) was 23 mm.

Next, holes (3) each having a width of 5 mm and a length of 5 mm are punched in the center of the band-shaped metal foil (2) in one row at intervals of 5 m in the length direction of the band-shaped metal foil (2). Formed.

Next, a band-shaped metal foil (2
) are overlapped, and the intermediate part (2b) of a predetermined width formed between the holes (3) of the metal foil (2) is pressed in a direction perpendicular to the metal sheet (1) using the press (5). Then, these pressed portions were temporarily pressed against the band-shaped metal sheet (1) (FIGS. 5 and 6). The rolling reduction rate at this time was 8%.

After the temporary pressure bonding, the strip-shaped metal foil (2) is cut in the length direction so as to form a heat insulating line (4) that passes through both the left and right edges of the hole (3) or slightly inside the left and right edges of the hole (3). The metal foil is divided into non-pressure-welded pieces (2A) and metal foil temporary-pressure-welded pieces (2B) arranged alternately with holes (3), and the band-like metal foil non-pressure-welded pieces (2A) are similarly separated by air pressure of nitrogen gas. By peeling and removing, the metal foil temporarily pressed pieces (2B) arranged at predetermined intervals remained on the band-shaped metal sheet 1-(1).

Hereinafter, as in the case of Example 1, the metal sheet (1) having the metal foil temporary press-welding piece (2B) is passed between the secondary press-welding rolls (8) and (9) (Fig. 3), As a result, the metal foil fragment (2B) was brought into final pressure contact with the band-shaped metal sheet 1-(1), and then the metal sheet (1) and the metal foil fragment (2B
) are diffusion bonded, thereby forming a belt-shaped metal sheet (1
) is coated with an aluminum partial cladding layer (2S
4) The band-shaped metal sheet (1) having the aluminum partial cladding layer (2S) obtained by the method of the second invention also has a very precise cladding layer (2S) as in the embodiment of the first invention. It had dimensional accuracy and could be advantageously used, for example, as a lead frame for mounting an IC.

In the above embodiment, one row of dissimilar metal partial cladding layers (2S) is provided on the band-shaped metal sheet (1), but in some cases, two or more rows may be provided. Furthermore, the band-shaped metal sheet (1) having dissimilar metal partial cladding layers (2S) at regular intervals obtained by the method of the present invention can be applied not only to IC lead frames but also to other uses. .

Effects of the Invention As described above, in the method of the first invention, a band-shaped metal sheet (1) and a band-shaped metal foil (2) of a predetermined width made of a material different from this are prepared, and the band-shaped metal sheet (1) is prepared. A strip metal foil (2) is superimposed on at least one side of (1), and by pressing the strip metal foil (2) at regular intervals in a direction perpendicular to the metal sheet (1), these pressed parts are removed from the strip metal foil. After temporarily press-fitting the sheet (1), the band-shaped metal foil (2) is cut in the width direction so as to form a cutting line (4) that passes through the front and back edges of all the temporary press-fit parts, and then a substantially rectangular metal foil is cut. Metal foil non-pressure bonded pieces (other than the foil temporary pressure bonded piece (2B)
By peeling and removing 2A), a band-shaped metal sheet (1
) Temporary press-welded pieces of metal foil arranged at predetermined intervals on top (2B)
Then, the metal sheet (1) having the metal foil temporary press-bonded fragment (2B) is passed through the secondary press-bonding rolls (8) and (9).
As a result, the gold B foil temporarily pressed piece (2B) is brought into final press contact with the band-shaped metal sheet (1). At least one row of holes (3) having the required size are formed by processing at predetermined intervals in the length direction of the strip metal foil (2), and the strip metal foil (2) is formed on at least one side of the strip metal sheet (1). The intermediate part (2b) of a predetermined width formed between the holes (3) of the metal foil (2) is placed in a direction perpendicular to the metal sheet (1) as in the case of the first invention. By pressing, these pressed parts are attached to the belt-shaped metal sheet 1.
- (1) is temporarily pressed, and then the band-shaped metal foil (2) is attached,
All are cut in the length direction so as to form a heat insulating line (4) that passes along the left and right edges of the hole (3) or slightly inside the left and right edges of the hole (3), and the strip metal foil non-pressure bonded piece (2A) and the hole (
3) and metal foil temporary press-bonded pieces (2B) arranged alternately, and then peel off and remove the band-shaped metal foil non-pressure-bonded pieces (28), thereby forming a predetermined area on the band-shaped metal sheet 1-(1). This is because the metal foil temporary press-welded pieces (2B) lined up at intervals are left, and then the metal foil temporary press-welded pieces (2B) are finally press-bonded to the band-shaped metal sheet (1) as in the case of the first invention. When a predetermined portion of the strip metal foil (2) made of a different material is temporarily pressed onto the strip metal sheet (1), the strip metal foil (2) is not wrinkled in the width direction. Therefore, a partial cladding layer made of metal foil (
2S) dimensional and positional accuracy can be sufficiently ensured. In addition, there is no possibility that a partial cladding layer is formed on both side edges of the metal sheet (1) as in the conventional method, and therefore the metal sheet 1- having dissimilar metal partial cladding layers obtained by the method of the present invention is The present invention has the advantage that it can also be applied to lead frame materials for packages equipped with pins.

[Brief explanation of drawings]

Figures 1 to 4 show the actual method of the first invention/11 of this invention.
1511I, in which Fig. 1 is a partial longitudinal cross-sectional view of the temporary pressure welding process, Fig. 2 is a plan view of the same, Fig. 3 is a partial longitudinal cross-sectional view of the main pressure welding process, and Fig. 4 is a partial vertical cross-sectional view of the material obtained by the method of the present invention. FIGS. 5 and 6 are partial plan views of a band-shaped metal sheet having a bottom cladding layer of dissimilar gold, showing an embodiment of the method of the second invention of the present invention, and FIG. Longitudinal sectional view, No. 6
The figure is a plan view of the same. (1)...Band-shaped metal sheet, (2)...Band-shaped metal foil, (2A)...Metal foil non-pressure-bonded fragment, (2B)...Metal foil temporary pressure-bond fragment, (2S)... Dissimilar metal partial cladding layer, (3)...hole, (4)...cutting line, (5)...
- Press, (8) (9)...roll for secondary pressure welding. that's all

Claims (2)

[Claims] (1) Prepare a band-shaped metal sheet (1) and a band-shaped metal foil (2) of a predetermined width made of a different material, and overlap the band-shaped metal foil (2) on at least one side of the band-shaped metal sheet (1). By pressing the metal foil strip (2) at regular intervals in a direction perpendicular to the metal sheet (1), these pressed parts are brought into temporary pressure contact with the metal sheet (1), and then the metal foil strip (2) is pressed against the metal sheet (1). ) is cut in the width direction so as to form a cutting line (4) passing through both front and rear edges of all the temporary press-welded parts, and then cut the metal foil non-pressure-welded pieces ( By peeling off and removing the metal foil (2A), the metal foil temporarily pressed pieces (2B) arranged at predetermined intervals remain on the band-shaped metal sheet (1), and then the metal foil (1) having the metal foil temporarily pressed pieces (2B) is removed. ) is passed between the secondary pressure welding rolls (8) and (9), and as a result, the metal foil temporary pressure bonded piece (2B) is brought into full pressure contact with the band-shaped metal sheet (1). A method of providing partial cladding layers of dissimilar metals at regular intervals. (2) Prepare a band-shaped metal sheet (1) and a band-shaped metal foil (2) made of a different material, and prepare a band-shaped metal foil (2).
At least one row of holes (3) having the required size are formed by punching at predetermined intervals in the length direction of the strip metal foil (2), and the strip metal foil (3) is formed on at least one side of the strip metal sheet (1). 2) and place the holes (3) in the metal foil (2).
) By pressing the intermediate part (2b) of a predetermined width formed between the metal sheet (1) in a direction perpendicular to the metal sheet (1), these pressed parts are temporarily pressed against the belt-shaped metal sheet (1), and then the belt-shaped The metal foil (2) is cut in the length direction so as to form a heat insulating line (4) that passes through both the left and right edges of the hole (3) or slightly inside the left and right edges of the hole (3) to obtain a band-shaped non-pressure-welded piece of metal foil. The band-shaped metal sheet (1 ), the metal foil temporary pressure bonding pieces (2B) arranged at predetermined intervals remain on the top of the metal foil temporary pressure bonding pieces (2B), and then the metal sheet (1) having the metal foil temporary pressure bonding pieces (2B) is transferred to the secondary pressure bonding rolls (8) (9). A method for providing partial cladding layers of dissimilar metals at regular intervals on a band-shaped metal sheet, characterized in that the temporary pressure-welded pieces of metal foil (2B) are brought into permanent pressure contact with the band-shaped metal sheet (1).