JPH06102273B2 - Method for manufacturing spot-shaped partial clad material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a spot-shaped partial clad material by superposition pressure welding and rolling, and relates to a metal foil piece having a required size at a high precision pitch on a substrate material that is fed at a fixed size. By pressing the material that has been temporarily fastened to control the rolling load so that it will have a predetermined thickness when rolling, and by detecting the pitch after rolling to control the rolling load, it is possible to obtain highly accurate pitch and dimensions. The present invention relates to a manufacturing method for obtaining a spot-shaped partial clad material.

BACKGROUND ART In recent years, there has been a strong demand for miniaturization of devices using integrated circuits, and flat packages have come to be widely used.

The lead frame (3) as shown in FIG. 6 in which terminals are provided in the four circumferential directions for such a flat package has a metal (Al, Ag, Cu, etc.) having good bondability attached to a portion where wire bonding is performed. It is necessary to provide a part.

In order to previously provide such a metal-deposited portion, it has been conventionally performed by a. Vapor deposition method and b. Plating method after processing into a lead frame, but a method having higher mass productivity has been desired.

That is, a. The evaporation method not only requires expensive equipment,
Since it is necessary to mask the unnecessary portions to be deposited, the vapor deposition speed is slow and the productivity is low. In addition, b. The plating method has a metal that cannot be plated, and there is a limit to the thickness that can be plated efficiently.

Further, in order to preliminarily provide the metal-deposited portion, as shown in FIG. 5, the metal-deposited portion (2) is provided in a spot shape on the lead frame material (1) with high accuracy, and press-working or A method of forming by etching can be considered.

For example, striped Al or Ag on the lead frame strip
A technique has been proposed (Japanese Patent Laid-Open No. 59-1078) for mechanically or chemically removing unnecessary portions so that a desired spot shape can be obtained after applying a foil by pressure rolling. The yield is poor, the efficiency is poor, such as masking the necessary parts for deposition and removing the unnecessary parts, and the required pitch with high accuracy,
It was difficult to provide a spot-like size.

It is also possible to produce a spot-shaped partial clad material of a certain length by stacking a piece of metal foil of a certain size on a certain position of a certain length of the substrate material, and pressing and rolling it. It is impossible to cut back the metal foil to be adhered with high precision with a certain size and length in succession, align it with high precision, and provisionally fix it continuously at the required pitch. Industrial mass production of clad materials was considered impossible.

On the other hand, a lead frame in which an Al foil is fastened to the lead frame material by spot welding and then clad is proposed (Japanese Patent Laid-Open No. 60-227456). No specific manufacturing method has been proposed for aligning with precision and for temporary temporary fixing, which makes practical application difficult.

Furthermore, if only temporarily fixed by spot welding, the Al foil will be constrained at the welded portion and problems will occur in its rollability.
There is a problem in that the required pitch and dimensional accuracy cannot be improved simply by performing pressure contact rolling.

That is, conventionally, the metal foil clad by pressure contact rolling is a stripe clad, and the target of control is the plate thickness, plate width, and shape, but the pitch fluctuation that occurs in the pressure contact rolling of the metal foil in which the metal foils are superposed at a predetermined pitch. Is due to variations in rolling conditions, plate thickness and plate width.

In particular, the influence of plate thickness fluctuation is very large. For example, when the material plate thickness is 0.254 mm, the material pitch is 30 mm, and the finished plate thickness is 0.15 mm, the pitch changes by 400 μm or more just by changing the finished plate thickness by 0.001 mm. become.

SUMMARY OF THE INVENTION In view of the present situation, the present invention cuts a metal foil to be adhered with a predetermined size and length with high accuracy, and, for example, aligns the metal foil with a lead frame material with high accuracy and continuously temporarily An object of the present invention is to provide a manufacturing method capable of obtaining a spot-shaped partial clad material having a highly accurate pitch and dimensions when the material is stopped, then pressure-bonded, rolled, and clad into a clad.

SUMMARY OF THE INVENTION The present invention is a manufacturing method for obtaining a spot-shaped partial clad material by pressure-rolling a material obtained by temporarily fixing metal foil pieces of required dimensions at a predetermined pitch on a substrate material, the dimensions of the substrate material and the metal foil piece. From the pitch, set the rolling load for obtaining the target pitch and the plate thickness from the pitch, press contact rolling by means of controlling the rolling load to the target, and further measure the pitch of the metal foil piece on the delivery side of the rolling mill. The method for producing a spot-shaped partial clad material is characterized in that the rolling force during continuous rolling is corrected and controlled according to the difference between the pitch measurement value and the target pitch.

Further, according to the present invention, in the above configuration, the pitch of the metal foil pieces is measured on the entrance side of the rolling mill, and the set value of the target load is corrected and controlled by the pitch measurement value before rolling. It is a method of manufacturing a material.

More specifically, the present invention is, for example, continuous spot welding of a metal foil and a substrate material, which have been fed at a constant size, at a predetermined interval and temporarily fixed, and then an unnecessary portion is cut and removed by a rotary cutter, or
At the same time as cutting and punching the metal foil fed at a fixed size with a punch, the punch is spot-welded as a current-carrying material on the substrate material that is fed at a fixed size and temporarily fixed, and a metal foil piece of the required size is temporarily fixed at a highly accurate pitch. After the material is obtained, the rolling load is controlled so as to have a predetermined thickness during the subsequent pressure welding and rolling, that is, the constant load control and the constant elongation control are cascade-controlled, and the pitch after rolling is detected to detect the target load. Is a manufacturing method for obtaining a spot-shaped partial clad material having a highly accurate pitch and dimension, which enables ultrahigh-precision plate thickness control.

Structure and effect of the invention Pitch variation of the metal foil piece in the pressure contact rolling of the substrate material, a.
This occurs due to fluctuations in the board thickness and b. Roll gap (plate thickness) fluctuations due to eccentricity of the rolling rolls. Therefore, it is necessary to control the plate thickness with ultra-high accuracy using feedback and feedforward.

In the present invention, in the pressure contact rolling, the rate of change of the strip width can be considered to be much smaller than the rate of change of the sheet thickness, and the pitch can be controlled by controlling the rolling rate Re to be constant.

V = L ₀ h ₀ b = L ₁ h ₁ b L ₀ = L ₁ h ₁ / h ₀ = L ₁ / Re V; volume, h ₁ ; base material sheet thickness, h ₀ ; rolled sheet thickness, b; sheet Width, L ₁ ; Base material pitch, L ₀ ; Rolling pitch By the way, the rolling load P k _m; deformation resistance, R; roll radius considering a flat, Q _P; denoted as rolling force function, although it is possible to control the pitch by controlling the rolling force as a target, rolling force function Q _{Since P} changes depending on the friction condition and the like, it is necessary to correct this.

Therefore, in this invention, a pitch measuring device provided on the delivery side of the rolling mill, the overall correction, including rolling force function Q _P in the continuous rolling, by feeding back to the control of the rolling load,
It enables ultra-high-precision thickness control and achieves the desired pitch control.

Furthermore, when setting the target rolling load, a pitch measuring device for a metal foil piece is provided on the rolling mill entrance side, and feed-forward of the pitch measured value before rolling is performed, or the target set value is constantly or appropriately corrected to obtain a plate thickness. The control can be made more precise and faster.

According to the present invention, disturbances such as a. Periodic fluctuations caused by eccentricity of rolling rolls, b. Gentle fluctuations due to the influence of the amount of oil film, etc. are generated in pressure contact rolling of substrate materials in which metal foils are superposed at a predetermined pitch. Therefore, it is possible to provide a material that enables ultra-high-precision pitch control and is excellent in mass productivity when forming a lead frame by press working or etching.

In the present invention, the substrate material serving as the clad base material can be any known material such as 42Ni-Fe system used as the lead frame material, and the metal foil pressed in spots is Ag, Ag-Cu, or the like. Known brazing materials such as Ag brazing material, Al.Cu and the like can be used.

Disclosure of the Invention Based on the Drawings FIG. 1 is a schematic explanatory view of a rolling mill showing a pressure contact rolling method according to the present invention.

2A, 2B and 2C are explanatory views showing the pitch measuring device.

FIGS. 3a, 3b, 3c, 3d and 3f are schematic explanatory views showing the manufacturing process of the rolled material, and FIGS. 3c and 3e are schematic explanatory views of the welding device and the cutting machine viewed from the line direction.

4A to 4E are schematic explanatory views of an embodiment of a constant size feeding and welding apparatus showing a manufacturing process of a rolled material, and FIG. 4A is an explanatory view seen from the line direction.

This invention, in the pressure contact rolling of the substrate material in which the metal foil is superposed at a predetermined position, that is, a predetermined pitch, the target rolling load for obtaining the target pitch and the plate thickness from the dimensions and the pitch of the substrate material and the metal foil piece. Set, hold the rolling load to a target, or pressure contact rolling by means of controlling to a required value, further, measuring the pitch of the metal foil piece on the rolling mill exit side, between the pitch measurement value and the target pitch. It is characterized in that the rolling force during continuous rolling is corrected and controlled according to the difference.

However, the target pitch cannot be controlled with high accuracy unless the metal foil is superposed on the base material of the rolled material with high accuracy. Therefore, first, a method for obtaining the material will be described.

Structure 1 As shown in FIG. 3, a metal foil (11) is fed to a predetermined position of the substrate material (10) by a guide mechanism, and the substrate material (13) is connected to a series spot welding device (13) whose electrodes can be opened and closed by the device. 10) and metal foil (11) are sent. At this time, it is necessary to allow for the predetermined feed amount in consideration of the amount of deformation by press rolling and finish rolling (see FIG. A).

When the electrode (14) is lifted and the welding current-carrying material (15) presses the metal foil (11) onto the substrate material (10), the electrode (14) is pressurized and energized to weld the metal foil ( (See Figures b and c).

At this time, it is desirable that the size of the metal-melted portion be welded so that it does not appear on the surface of the metal foil, and the welded portions may be arranged at one or more points in the width direction of the substrate material (10).

In particular, as shown in FIG. 3c, it is preferable to weld two points on both ends of the metal foil piece (11) in the width direction of the substrate material (10), and only the tip side that is caught in the roll at the time of rolling in the subsequent process. By temporarily fixing and making the rear end side free, pressure welding and rolling property are improved.

A metal foil (11) fixed to a portion of the substrate material (10) located at an integral multiple of a predetermined pitch from the above welding device is cut into a predetermined length by a circular cutter (16) arranged at a predetermined interval, and the metal foil (11) is cut. ) Is shaped (see figures d and e).

At this time, it is necessary to allow for the amount of deformation of the predetermined length by pressure contact rolling and finish rolling.

After cutting, by removing the non-welded portion, it is possible to obtain a metal foil piece (12) having a predetermined size that is temporarily fixed by spot welding and has a good shape.

For example, after performing the above steps, by repeating the cycle of performing the steps simultaneously,
A substrate material (10) is obtained by temporarily temporarily fixing metal foil pieces (12) at a required pitch. The metal foil piece (1
The substrate material (10) obtained by temporarily fixing 2) can be once wound around a coil, or can be directly transferred to the pressure contact rolling step after the above steps (1) to (3) are completed.

However, whichever method is adopted, pressure contact and reduction of rolling property (damage to the metal foil piece (12), position of the metal foil piece (12) due to restraint by temporarily fixing the metal foil piece (12) as described above are caused. Considering that a highly accurate shape cannot be obtained due to misalignment, wrinkles, etc.), it is desirable that only the front end side that bites into the roll during rolling is temporarily fixed and the rear end side is free.

Structure 2 As shown in FIG. A metal foil (11) having a predetermined width is fed into the cutting device by a predetermined amount by a constant-size feeding device having an attaching / detaching mechanism by a suction machine (21).
(See Figure c) When the metal foil (11) of a predetermined length overhangs from the end face of the guide (20), the punch (22) is lowered and the metal foil (1
Cut 1) into metal foil pieces (12). (See Figure d) When the metal foil piece (12) cut by the punch (22) is pressed against the substrate material (10), pressure is applied to the roller electrode (23) to weld the metal foil piece (12) (e). See figure). The welding conditions at this time are preferably the same as those described above.

After the spot welding is completed, the substrate material (10) is fed by the constant-size feeding device in a predetermined amount, that is, an amount in which the deformation amount due to the pressure contact rolling and the finish rolling is expected.

For example, After performing the process at the same time, By repeating the process cycle, the metal foil strip (1
A substrate material (10) in which 2) is temporarily temporarily fixed at a required pitch is obtained. The substrate material (10) obtained by temporarily fixing the metal foil pieces (12) thus obtained is once wound around a coil, or It is possible to directly shift to the pressure contact rolling step after the step of (3) is finished, and it is also the same as that described above in consideration of the temporary fixing point in order to improve the pressure contact and the rolling property.

Next, a method for press-rolling the obtained substrate material (10) and metal foil piece (12) will be described. In the following method, the substrate material (10) formed by temporarily fixing the metal foil piece (12) described above.
Uses a coil once wound up.

As shown in FIG. 1, the rolling mill (30) has a structure in which a backup roll (32) is brought into contact with a pair of work rolls (31) to pressurize the rewound substrate material (10). Equipped with a device and a plate thickness gauge, the rolling load control device performs constant load control.

Further, a metal foil piece pitch measuring device on the exit side of the rolling mill (30), here, an optical sensor (33), a high precision encoder (34)
Is provided.

The control method consists of the following procedures.

I Based on the measured value of the rolling load and the measured value of the pitch at that time, the quantitative relationship between the variation of the rolling load and the variation of the pitch and the control model are obtained, and II the target rolling load for obtaining the predetermined pitch is calculated. , III The constant load control is performed by outputting the rolling load as a control reference.

IV In addition, the pitch measurement results are fed back to the rolling load control device to appropriately correct the control model for a control error and make a comprehensive correction.

With such control, it is possible to control the plate thickness with extremely high precision during rolling, and it is possible to realize the target high precision pitch control.

Further, in II, the pitch measurement value before rolling can be feed-forwarded, and the target set value of rolling load can be corrected constantly or appropriately.

As shown in FIG. 2, a known sensor such as an optical sensor (33) is used for the metal foil piece pitch measuring device to measure the substrate material (10).
Detects a metal foil piece (12) in the width direction (Fig. A), substrate material (10)
In addition to detecting the metal foil piece (12) in the longitudinal direction (Fig. C), the pitch of the metal foil piece (12) can be measured by using the optical sensor (33) and the high-precision encoder (34) (Fig. B).

Practical example 10mm with the sandwich cutting and spot welding method shown in Fig. 4.
42mm width, 0.25mm thickness 42Ni-Fe material, which was temporarily fixed with width, 10μm thickness, 6.4mm length of Al foil piece at 36.0mm pitch, and the target substrate material thickness after rolling was 0.15mm, Al The target pitch of the foil pieces was set to 60.0 mm.

For example, in the rolling mill shown in FIG. 1, the backup roll is periodically eccentric, and the rolling force fluctuates due to other rolling conditions. Due to such fluctuation, the pitch fluctuation width of the metal foil piece is about It becomes ± 800 μm.

To keep the target pitch accuracy within ± 300 μm to ± 100 μm, the tacking accuracy is ± 30 μm at 0.25t and ± 50 at 0.15t.
If the pitch accuracy is ± 300 μm, it is necessary to control the rolling thickness control accuracy width in the submicron order. Therefore, it is considered difficult to simply control the rolling thickness as the pitch control.

The effect of roll eccentricity on the plate thickness is that if the load variation on the kiss roll fluctuates by ± 0.5 ton, the gap variation is ± 2 μm at a mill constant of 74 ton / mm, and the plate thickness is about 1/2 of that. 1
Equivalent to μm, and if the plate thickness fluctuates ± 1 μm, it extends ± 60
It varies by 0 μm.

Therefore, by using the rolling mill shown in FIG. 1, the cascade control system of constant load control and constant elongation control and the measurement result by the metal foil piece pitch measuring device are fed back to the rolling load control device for correction. When rolled by the control method, it is 10mm width, 10.7mm on the substrate material of 42mm width, 0.15mm thickness.
The length of Al foil piece can be clad, and the pitch accuracy is improved more than 10 times compared with the method that does not control the rolling load.
A material in which the foil pieces were partially clad in spots could be obtained.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a rolling mill showing a pressure contact rolling method according to the present invention. 2A, 2B and 2C are explanatory views showing the pitch measuring device. FIGS. 3a, 3b, 3c, 3d and 3f are schematic explanatory views showing the manufacturing process of the rolled material, and FIGS. 3c and 3e are schematic explanatory views of the welding device and the cutting machine viewed from the line direction. 4A to 4E are schematic explanatory views of an embodiment of a constant size feeding and welding apparatus showing a manufacturing process of a rolled material, and FIG. 4A is an explanatory view seen from the line direction. FIG. 5 is a perspective explanatory view of the spot-shaped partial clad material. FIG. 6 is an explanatory diagram showing an example of a lead frame. 10 …… Substrate material, 11 …… Metal foil, 12 …… Metal foil piece, 13 ……
Welding equipment, 14 ... Electrode, 15 ... Conductive material, 16 ... Circular cutter, 20 ... Material guide, 21 ... Adsorption machine, 22 ... Punch, 23 ... Roller electrode, 30 ... Rolling machine, 31 …… Work roll, 32 …… Backup roll, 33 …… Optical sensor, 34 …… High precision rotary encoder.

Continuation of the front page (56) References JP-A-59-141389 (JP, A) JP-A-59-174287 (JP, A) JP-A-62-224484 (JP, A)

Claims (2)

[Claims] 1. A manufacturing method for obtaining a spot-shaped partially clad material by pressure-rolling a material in which metal foil pieces of a predetermined size are temporarily fixed on a substrate material, the dimensions and pitches of the substrate material and the metal foil piece. More, by setting the rolling load for obtaining the target pitch and plate thickness, pressure contact rolling by means of controlling the rolling load to the target, further,
A method for manufacturing a spot-shaped partial clad material, characterized in that the pitch of a metal foil piece is measured on the delivery side of a rolling mill, and the rolling reduction force during continuous rolling is corrected and controlled according to the difference between the pitch measurement value and a target pitch. . 2. The spot-shaped partial clad according to claim 1, wherein the pitch of the metal foil pieces is measured on the entrance side of the rolling mill, and the set value of the target load is corrected and controlled by the pitch measurement value before rolling. Method of manufacturing wood.