JPH0742593B2 - Manufacturing method of lead frame with partial plating - 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 of manufacturing a lead frame with partial plating, in which replacement plating of Au or Ag partial plating for bonding is attached to the side surface or the back surface of a lead pin, a die pad portion or the like. Disappeared,
The feature of the present invention is that the shape inspection can be performed only once without deformation of the lead pin, and the apparatus and process can be simplified and the processing time can be shortened.

[0002]

2. Description of the Related Art A lead frame for mounting a transistor, an IC chip, or the like has a frame pattern of a predetermined shape formed of a die pad portion (also called an island) and a large number of lead pins.
Partial plating for Ag and Bonding is applied. As a method of manufacturing such a lead frame with partial plating, a thin plate-shaped lead frame material (material such as 42-Alloy or Cu-Alloy) is generally used in the past.
First, a frame pattern having a predetermined shape as described above is formed, and then a predetermined portion of the pattern is partially plated for bonding.

Among the above manufacturing processes, as a means for forming a frame pattern on a lead frame material, there is a photo-etching method in response to the recent increase in the number of pins and miniaturization of the lead frame. For the frame, many punching methods by press are still used. Also,
As means for performing partial plating on the lead frame after forming the frame pattern, a lead film may be laminated with a punching film that is open only at portions where partial plating is required, or photoresist ink may be applied to portions where partial plating is not necessary (for example, (See Japanese Laid-Open Patent Publication No. 57-79194), and plating treatment is performed. However, in a general lead frame, it is still possible to perform a plating treatment by mechanically pressing the elastic sealing material, which is opened only at the portions required for partial plating, to the lead frame (see, for example, Japanese Patent Publication No. 57-15675). It is widely practiced.

[0004]

However, the above-mentioned conventional method of manufacturing a lead frame with partial plating has the following problems. a First, in the case where the frame pattern is formed on the lead frame by punching with a press, it is necessary to perform a shape inspection for all the lead pins after the frame pattern is formed, and after the partial plating treatment, Had to carry out shape inspection on all of them.

B Next, the one in which the elastic sealing material is mechanically pressed onto the lead frame after the frame pattern is formed to carry out the partial plating for bonding has a problem in the sealing accuracy, and the lead pin 9 is The displacement of the plating solution easily occurred on the side surface, and the displacement plating 16 was deposited (see FIG. 25). Since the coating film of the displacement plating 16 is easily peeled off, it may come into contact with the adjacent lead pin 9 and cause a leak,
If the pin length is short, the film of the displacement plating 16 may extend outside the package, impairing the package effect.

[0006] Similarly, in the case where the elastic sealing material is mechanically pressed to perform partial plating for bonding, a driving device for the sealing material is complicated and large-scaled, and intermittent movement for temporarily stopping the plating process is required. Because it is necessary
The processing speed was slow and the productivity was lacking.

The present invention is intended to solve the above problems of the conventional method of manufacturing a lead frame with partial plating. That is, the purpose is to prevent the plating from adhering to the side surface or the back surface of the lead pin or the die pad portion, to prevent the leakage and the package effect from being impaired, and to eliminate the deformation of the lead pin in the partial plating treatment step, thereby improving the shape. It is an object of the present invention to provide a method for manufacturing a lead frame with partial plating, which allows the inspection to be performed only once in the final finishing step and simplifies the apparatus and process and shortens the processing time.

[0008]

A first method of manufacturing a lead frame with partial plating according to the present invention is shown in FIG.
And a masking tape 2 is formed on the surface of a long lead frame material 1 (see FIG. 3) before forming a frame pattern, the masking tape 2 having an opening 3 as a portion required for partial plating for bonding (see FIG. 4, Next, the lead frame material 1 is passed through a treatment bath for strike plating, and the portion exposed from the opening 3 of the masking tape 2 is subjected to Cu strike plating 4 (see FIG. 5).
Next, the lead frame material 1 is passed through a treatment tank for partial plating for bonding, and partial plating 5 for bonding is applied on the strike plating 4 (see FIG. 6). 1 through a treatment tank for cover plating to apply Cu protective cover plating 6 on the partial plating 5 (see FIG. 7), and then peel off the masking tape 2 (see FIG. 8). The lead frame material 1 is punched by a press (see FIG. 9) to form a frame pattern (see FIG. 10), and after degreasing, the protective cover plating 6 on the partial plating 5 is peeled and removed. (See FIG. 11), the partially plated lead frame as shown in FIG. 21 is manufactured.

The second method of manufacturing a lead frame with partial plating according to the present invention comprises the steps as shown in FIG. 2, and is a long surface of the lead frame material 1 (see FIG. 12) before frame pattern formation. A masking tape 2 having openings 3 for the required partial plating for bonding
(See FIGS. 13 and 20), and then the lead frame material 1 is passed through a treatment bath for strike plating, and Cu strike plating 4 is applied to the portion exposed from the opening 3 of the masking tape 2. Giving (see Figure 14),
Next, the lead frame material 1 is passed through a treatment tank for partial plating for bonding, and the partial plating 5 is formed on the strike plating 4 slightly thicker than the thickness required for bonding.
(See FIG. 15), and then the masking tape 2
After peeling off (see FIG. 16), the lead frame material 1 is punched by a press (see FIG. 17) to form a frame pattern (see FIG. 18), and after degreasing, By removing the surface of the plating 5 (see FIG. 19), a partially plated lead frame as shown in FIG. 21 is manufactured. In the figure, 7 is a press die, 8 is a lead frame after forming a frame pattern, 9 is a lead pin, and 10 is a die pad portion.

[0010]

As described above, in the method of manufacturing a lead frame with partial plating according to the present invention, the masking tape 2 is provided on the surface of the lead frame material 1 before the frame pattern is formed, with the opening 3 being a portion required for partial plating for bonding. Is laminated and passed through a treatment tank for strike plating, a treatment tank for bonding partial plating, a treatment tank for cover plating, etc. to perform each plating treatment. Therefore, by continuously moving the long lead frame material 1 in each plating treatment tank as in the case of the entire surface plating, the plating treatment can be performed only on the portions required for partial plating exposed from the masking tape 2. Unlike the conventional case, it is not necessary to provide mechanical sealing means or intermittent moving means in each plating tank, so that the equipment and process can be simplified and the processing speed is greatly improved. .

II In the manufacturing method according to the present invention, as described above, the surface of the thin plate-shaped lead frame material 1 before forming the frame pattern is partially plated for bonding, and then the frame pattern is punched by press working. ing. Therefore, the lead pins 9 and the die pad portion 10 formed by punching after the plating should have no plating adhered to the side surface and the back surface thereof, and the lead pin 9 and the die pad portion 10 should not be attached.
The partial plating 5 is attached only to the bonding required partial plating area. The displacement plating does not deposit on the side surface or the back surface of the lead pin or the die pad portion unlike the conventional case.

Similarly, in the manufacturing method according to the present invention, the displacement plating does not deposit on the side surface of the lead pin 9 or the die pad portion 10 as described above, and thus the side surface or the back surface of the lead pin or the die pad portion is different from the conventional case. There is no need for a step of roughening the base material of the lead frame made of copper or removing the thick displacement plating adhered to the side surface of the lead frame made of 42Alloy by peeling off the displacement plating attached to.

IV As described above, in the manufacturing method according to the present invention, the lead frame material 1 before the frame pattern is punched by press working is subjected to the partial plating 5 for bonding. Therefore, since the lead frame material 1 used for the partial plating for bonding is a thin plate without a frame pattern, the partial plating process on the surface thereof can be easily and quickly performed. Unlike the conventional case of performing high-speed partial plating on a lead frame after forming a frame pattern, the lead pin 9 does not deform during partial plating, and it is not necessary to perform a deformation inspection after partial plating. It only needs to be done once at the final finishing stage such as cutting and leveling.

In addition, as described above, in the manufacturing method according to the present invention, the frame pattern is formed by press punching after the lead frame material 1 is subjected to the partial plating 5 for bonding, but before the press punching process, In the first manufacturing method, Cu protective cover plating 6 is applied on the partial plating 5, and in the second manufacturing method, the partial plating 5 is applied slightly thicker than the thickness required for bonding. Therefore, even if mechanical oil or the like adheres to the lead frame material 1 by press punching, the surfaces of the Cu protective cover plating 6 and the thicker partial plating 5 that will be peeled off later will not have internal partial plating necessary for bonding. 5 is protected, and bonding can be performed without any trouble.

[0015]

EXAMPLES In the method for manufacturing a lead frame with partial plating according to the present invention, a long lead frame material 1 is used.
Is a copper material or 42 Alloy material, for example, and a long one wound in a coil shape may be used.

The masking tape 2 only needs to have heat resistance and chemical resistance. For example, polyester, polyethylene, polypropylene, polyvinyl chloride, etc. or their derivatives, or a synthetic resin of a composite of these and other components may be used. You can use it. In order to laminate the masking tape 2 on the surface of the lead frame material 1, for example, a thermosetting adhesive may be applied to the back surface of the masking tape 2, and in this case, residue of the adhesive remains at the time of peeling later. Absent. Further, the masking tape 2 is formed by punching the necessary portions for partial plating for bonding.
At the same time, a positioning hole 1 formed in the lead frame material 1
Positioning holes 17 corresponding to No. 8 are formed in advance to perform positioning during lamination.

As the protective cover plating 6, Cu plating is applied on the bonding partial plating 5, for example, 0.3 to 1.0.
It may be formed in a thickness of about μm. Further, in the case where the partial plating 5 is slightly thicker than the thickness required for bonding instead of the protective cover plating 6, an additional thickness of, for example, about 0.3 to 1.0 μm is formed in addition to the thickness required for bonding. Just keep it. The surface of the protective cover plating 6 or the partial plating 5 may be peeled off by electrolytic peeling or chemical peeling.

In the illustrated embodiment, the tip end portion of the lead pin 9 is flat (see FIG. 22). However, the lead pin 9 may be depressed to have a concave portion (see FIG. 23). Good. The long lead frame material 1 and the lead frame 8 are continuously moved on each processing tank. In each processing tank, as shown in FIG.
The surface of the lead frame 8 faces downward, and the plating solution and other processing solutions are jetted from below to perform processing. In FIG. 24, 11 is a plating liquid pressure chamber, 12 is a nozzle portion, and 13
Is an anode, 14 is a reserve tank, and 15 is a pump.

[0019]

As is apparent from the above, the method of manufacturing a lead frame with plating according to the present invention has the following effects. According to the manufacturing method of the present invention, the lead frame material before forming the frame pattern is partially plated for bonding, and then the frame pattern is punched by press working. Therefore, unlike the conventional manufacturing method of this type, the plating does not adhere to the side surface or the back surface of the lead pin or the die pad portion, and the partial plating can be applied only to the bonding required partial plating.
Therefore, it is possible to prevent leakage due to displacement plating and damage to the package effect.

B In the manufacturing method according to the present invention, the displacement plating does not adhere to the side surface or the back surface of the lead pin or the die pad portion as described above. Therefore, unlike the conventional manufacturing method of this type, it is possible to simplify the process by eliminating the work of peeling and removing the displacement plating, and it is possible to prevent the base of the lead frame from being roughened by the peeling process.

C In the manufacturing method according to the present invention, various plating treatments are carried out by laminating a lead frame material with a masking tape having openings required for partial plating for bonding. Therefore, unlike the conventional manufacturing method of this type, it is not necessary to provide a mechanical sealing means or an intermittent moving means in each plating tank, and the lead frame material and the lead frame are the same as in the case of the whole surface plating. Can be moved continuously to perform each treatment. Therefore, the processing speed can be greatly improved to 4 times or more (compared to our company) of the conventional one, and the process and the entire apparatus can be simplified.

D In the manufacturing method according to the present invention, the lead frame material before punching and forming the frame pattern as described above is subjected to partial plating for bonding.
Therefore, unlike the conventional manufacturing method of this type, since the lead frame material at the time of partial plating is a thin plate without a frame pattern, the surface can be partially and easily plated. There is no need to deform the lead pins during partial plating as in the case of performing high-speed partial plating after forming a conventional frame pattern, and it is not necessary to inspect all of them after partial plating. It would be good to carry out the inspection.

In the manufacturing method according to the present invention, before the stamping for forming the frame pattern, in the first manufacturing method, the protective cover plating of Cu is applied on the partial plating, and the second manufacturing method is performed. In the method, the partial plating is formed slightly thicker than the thickness required for bonding.
Therefore, even if mechanical oil etc. adheres during the press punching process, the protective cover plating or thick partial plating surface that will be peeled off later protects the internal partial plating required for bonding, which may cause problems during bonding. There is no.

[Brief description of drawings]

FIG. 1 is a flow chart diagram showing a process sequence of an embodiment of a first manufacturing method according to the present invention.

FIG. 2 is a flow chart diagram showing a process sequence of a second embodiment of the manufacturing method according to the present invention.

FIG. 3 is a partially enlarged vertical front view showing a lead frame material in the first embodiment of the manufacturing method according to the present invention.

FIG. 4 is a partially enlarged vertical sectional front view showing a state after the masking tape is laminated in the embodiment of the first manufacturing method according to the present invention.

FIG. 5 is a partially enlarged vertical front view showing a state after strike plating in the first embodiment of the manufacturing method according to the present invention.

FIG. 6 is a partially enlarged vertical front view showing a state after the partial plating for bonding in the first embodiment of the manufacturing method according to the present invention.

FIG. 7 is a partially enlarged vertical sectional front view showing a state after plating of the protective cover in the embodiment of the first manufacturing method according to the present invention.

FIG. 8 is a partially enlarged vertical sectional front view showing when the masking tape is peeled off in the embodiment of the first manufacturing method according to the present invention.

FIG. 9 is a partially enlarged vertical sectional front view showing the frame pattern punching formation in the first embodiment of the manufacturing method according to the present invention.

FIG. 10 is a partially enlarged vertical front view showing the state after the frame pattern is formed in the first embodiment of the manufacturing method according to the present invention.

FIG. 11 is a partially enlarged vertical front view showing a lead frame with partial plating manufactured in an example of the first manufacturing method according to the present invention.

FIG. 12 is a partially enlarged vertical front view showing the lead frame material in the second embodiment of the manufacturing method according to the present invention.

FIG. 13 is a partially enlarged vertical front view showing a state after the masking tape is laminated in the example of the second manufacturing method according to the present invention.

FIG. 14 is a partially enlarged vertical front view showing the state after strike plating in the second embodiment of the manufacturing method according to the present invention.

FIG. 15 is a partially enlarged vertical sectional front view showing a state after a partial plating for thick bonding in the second embodiment of the manufacturing method according to the present invention.

FIG. 16 is a partially enlarged vertical front view showing the time of peeling of the masking tape in the second embodiment of the manufacturing method according to the present invention.

FIG. 17 is a partially enlarged vertical front view showing the second embodiment of the manufacturing method according to the present invention during punching of the frame pattern.

FIG. 18 is a partially enlarged vertical front view showing a state after the frame pattern is formed in the second embodiment of the manufacturing method according to the present invention.

FIG. 19 is a partially enlarged vertical sectional front view showing a partially plated lead frame manufactured in an example of a second manufacturing method according to the present invention.

FIG. 20 is a perspective view showing a part after the masking tape is laminated in the embodiment of the manufacturing method according to the present invention.

FIG. 21 is a partially enlarged perspective view showing a lead frame with partial plating manufactured by the embodiment of the manufacturing method according to the present invention.

FIG. 22 is an enlarged perspective view showing one of the lead pins of the lead frame with partial plating manufactured by the embodiment of the manufacturing method according to the present invention.

FIG. 23 is an enlarged perspective view showing another example of the lead pin of the partially plated lead frame manufactured by the embodiment of the manufacturing method according to the present invention.

FIG. 24 is a vertical cross-sectional side view showing a part of a manufacturing apparatus example for carrying out the manufacturing method according to the present invention.

FIG. 25 is an enlarged perspective view of a lead pin showing a part of a lead frame with partial plating manufactured by a conventional manufacturing method.

[Explanation of symbols]

1-Lead Frame Material 2-Masking Tape 3-Opening 4-Strike Plating 5-Partial Plating 6-Protective Cover Plating 7-Press Die 8-Lead Frame 9-Lead Pin 10-Die Pad 11-Plating Liquid Pressure Chamber 12- Nozzle part 13-Anode 14-Reservoir tank 15-Pump 16-Displacement plating 17-Positioning hole 18-Positioning hole

Claims (2)

[Claims] 1. A long-length masking tape 2 having an opening 3 at a portion required for partial plating for bonding is laminated on the surface of a lead frame material 1 before forming a frame pattern, and then the lead frame material 1 is striked. Open the masking tape 2 opening 3 through the plating bath.
Cu strike plating 4 is applied to the exposed portion, and then the lead frame material 1 is passed through a treatment tank for partial plating for bonding to form the strike plating 4 mentioned above.
Partial plating 5 for bonding is applied on top, then the lead frame material 1 is passed through a treatment tank for cover plating, protective cover plating 6 of Cu is applied on the partial plating 5, and then the masking tape is applied. 2 is peeled off, the lead frame material 1 is punched by a press to form a frame pattern, and after degreasing, the protective cover plating 6 on the partial plating 5 is peeled off and removed. The method for manufacturing a lead frame with partial plating. 2. A long strip of the lead frame material 1 on which a frame pattern has not yet been formed is laminated with a masking tape 2 having an opening 3 for a portion required for partial plating for bonding, and then the lead frame material 1 is striked. Open the masking tape 2 opening 3 through the plating bath.
Cu strike plating 4 is applied to the exposed portion, and then the lead frame material 1 is passed through a treatment tank for partial plating for bonding to form the strike plating 4 mentioned above.
Partial plating 5 is applied to the top of the lead frame material to a thickness slightly larger than that required for bonding, the masking tape 2 is then peeled off, the lead frame material 1 is punched by a press to form a frame pattern, and then degreasing is performed. A method of manufacturing a lead frame with partial plating, characterized in that the surface of the partial plating 5 is peeled off after the treatment.