JPH07335810A - Electrolytic surface processing apparatus for lead frame for electronic parts - Google Patents

Abstract

PURPOSE:To shorten processing time and reduce uneven processing by making uniform in the width direction of a lead frame current density among a lead frame and both electrode plates 12, 13 disposed on opposite sides of the lead frame when the surface of the lead frame A is surface processed with electrolysis. CONSTITUTION:A surface between those of both electrode plates 12, 13 facing a lead frame A is formed into middle height surfaces 12c, 13c which is high in the vicinity of the center of the lead frame in the width direction and is inclined progressively lower toward left and right longitudinal side edges A', A'' of the lead frame in the width direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin metal plate lead frame used in the manufacture of electronic parts such as ICs, and electrolyzes burrs generated when molding a synthetic resin mold portion on the lead frame. The electrolytic deburring treatment of removing by means of, or the electrolytic degreasing treatment of removing oils and fats adhered to the surface of the lead frame by electrolysis, or the electrolytic degreasing treatment followed by the removal of metal The present invention relates to an apparatus for performing electrolytic surface treatment such as electrolytic plating treatment.

[0002]

2. Description of the Related Art Generally, a metal electrolytic plating process for a lead frame is well known in the art, and as shown in FIG. 5, a pair of left and right flat plate-like plates are formed in a processing bath 1 containing a processing solution. Electrode plates 2 and 3 are provided, and a lead frame A is placed between the two electrode plates 2 and 3 of the treatment liquid so that the lead frame A is substantially parallel to both electrode plates 2 and 3. After immersing in, the both electrode plates 2 and 3 are used as anodes,
Electrolysis is performed using the lead frame A as a cathode.

In the electrolytic deburring process or electrolytic degreasing process, electrolysis is performed using the lead frame A as a cathode or an anode and both electrode plates 2 and 3 as an anode or a cathode.

[0004]

By the way, in these electrolysis, the current density between the two electrode plates 2 and 3 and the lead frame A inserted between them is substantially different in the longitudinal direction of the lead frame A. Although uniform,
Regarding the width direction of the lead frame A, there is a phenomenon that current concentrates near the left and right longitudinal side edges A ′, A ″ of the lead frame A. , A ″ in the vicinity of the central portion in the width direction of the lead frame A, and lower in the vicinity of the central portion in the width direction of the lead frame A.
Electrolytic treatment of the vicinity of the center of the width direction of the
This is later than the electrolytic treatment for the vicinity of the left and right longitudinal side edges A ′, A ″ of the lead frame A.

However, in general, the lead frame A is provided with main parts such as various lead terminals A2 in the vicinity of the central portion in the width direction as shown in FIG. It is necessary to perform various surface treatments mainly on the main parts such as the lead terminals A2. Therefore, in the above-mentioned conventional surface treatment apparatus,
Due to the delay of the surface treatment for the vicinity of the center portion in the width direction of the lead frame A, it takes a long time to perform a predetermined surface treatment on each lead terminal A2 or the like which is a necessary portion of the lead frame A. Therefore, not only the processing capacity is low and the cost required for the processing is considerably increased, but also in the vicinity of the left and right side surface edges in the width direction of the lead frame A and in the vicinity of the center portion of the lead frame in the width direction. There was a problem that uneven processing occurred during the process.

The present invention focuses on the fact that the current density during surface treatment of a lead frame by electrolysis is substantially proportional to the distance between the lead frame and the electrode plate. It is a technical object to provide an electrolytic surface treatment apparatus that has been resolved.

[0007]

In order to achieve this technical object, the present invention provides "an electrode plate is provided on each of the left and right sides of the lead frame immersed in the treatment liquid in the treatment tank, and the electrode plate is the lead frame. In the electrolytic surface treatment device arranged to extend along the longitudinal direction of the electrode plate, the surface of the electrode plates facing the lead frame is high near the center portion in the width direction of the lead frame, It is formed on the middle-high surface which is gradually lowered toward the left and right long side edges in the width direction of the lead frame. "

[0008]

[Operation] As described above, the surface of the two electrode plates facing the lead frame located between them is high near the widthwise central portion of the leadframe, and the left and right long side edges of the leadframe in the width direction are provided. The height between the electrode plates and the lead frame is small in the vicinity of the center of the lead frame in the width direction. It gradually increases toward the side edges.

On the other hand, since the current density between both electrode plates and the lead frame is substantially proportional to the distance between them, the current density between both electrode plates and the lead frame is the width direction of the lead frame. The tendency of being higher in the vicinity of the left and right longitudinal side edges and becoming lower in the vicinity of the widthwise central portion of the lead frame can be corrected by forming the surfaces of the both electrode plates in the middle-high surface as described above. , The current density in the width direction of the lead frame can be made uniform, and in some cases, the current density in the vicinity of the widthwise central portion of the lead frame can be calculated by changing the width direction of the lead frame to the left and right long side surfaces. It can be higher than the current density near the edges.

[0010]

Therefore, according to the present invention, it is possible to prevent the surface treatment of the lead frame near the central portion in the width direction from being delayed during the electrolytic surface treatment of the lead frame, which is necessary for the surface treatment of the lead frame. Since the time can be shortened, the processing capacity can be improved, and the cost required for processing can be greatly reduced.
This has the effect of reducing the processing unevenness between the vicinity of the left and right side edges of the lead frame A in the width direction and the vicinity of the center portion of the lead frame in the width direction.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings of FIGS. In the figure, reference numeral 11 indicates a processing bath containing a processing liquid. A long hoop-shaped lead frame A is placed in the processing liquid in the processing bath 11 at the one end of the processing bath 11. Side plate 1
After entering through the slit hole 11a formed in 1 ', the slit hole 11b formed in the side plate 11 "at the other end of the processing tank 11 is soaked as to go out, and in this state, the slit hole 11b is appropriately lengthened. It is configured to transfer at a speed.

The treatment liquid in the treatment tank 11 flows out from the slit holes 11a and 11b.
The processing liquid that has flowed out is received by a receiving tank (not shown) and then returned to the processing tank 11. Also,
Electrode plates 12 and 13 are arranged on the left and right sides of the lead frame A in the processing tank 11 so that the electrode plates 12 and 13 extend substantially parallel to the longitudinal direction of the lead frame A. ing.

The surface of the two electrode plates 12 and 13 facing the lead frame A has a flat surface 12 near the center of the lead frame in the width direction.
a, 13a and inclined surfaces 12b ', 12b ", 13 which gradually decrease from the high planes 12a, 13a toward the left and right longitudinal side edges A', A" in the width direction of the lead frame A.
It is formed on the middle-high surfaces 12c and 13c composed of b'and 13b ".

In this structure, the surface of the hoop-shaped lead frame A is electrolyzed by energizing the lead frame A and both electrode plates 12 and 13 while transferring the lead frame A in its longitudinal direction. The surface treatment can be carried out continuously by. In this case, the surface of the two electrode plates 12, 13 facing the lead frame A located between them is formed as the middle-high surfaces 12c, 13c as described above.
The distance between the lead frame A and the lead frame A is small in the vicinity of the center portion in the width direction of the lead frame A, and gradually increases toward the left and right longitudinal side edges A ′, A ″ in the width direction of the lead frame A.

On the other hand, since the current density between the electrode plates 12 and 13 and the lead frame A is approximately proportional to the distance between them, the current density between the electrode plates 12 and 13 and the lead frame A is large. The density tends to be high near the left and right longitudinal side edges A ′, A ″ in the width direction of the lead frame A and low near the center of the lead frame A in the width direction. This can be corrected by forming the surfaces on the middle-high surfaces 12c and 13c as described above, and the current density in the width direction of the lead frame A can be made uniform, and in some cases, the lead frame A Of the current density in the vicinity of the center portion in the width direction of the lead frame A in the vicinity of the left and right longitudinal side edges A ′, A ″ in the width direction. It is possible to be higher than the degree.

Although the above-mentioned embodiment shows the case of applying the electrolytic surface treatment to the long hoop-shaped lead frame, the present invention is not limited to this, and a strip-shaped lead frame having an appropriate length can be used. It goes without saying that the same applies to the case. Further, the middle-high surfaces 12c and 13c are the flat surfaces 12a and 13a and the inclined surface 12 as in the above embodiment.
The structure is not limited to b ', 12b ", 13b', 13b", but may be an arcuate curved surface.

[Brief description of drawings]

FIG. 1 is a plan view of a lead frame.

FIG. 2 is a partially cutaway perspective view showing a surface treatment apparatus according to an embodiment of the present invention.

FIG. 3 is a plan view showing a surface treatment apparatus according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a vertical sectional front view of a conventional surface treatment apparatus.

[Explanation of symbols]

 A Lead frame A ′, A ″ Lead frame longitudinal side edges 11 Processing tank 12, 13 Electrode plate 12c, 13c Middle-high surface

Claims (1)

[Claims] 1. An electrolytic surface comprising an electrode plate disposed on each of the left and right sides of a lead frame immersed in a treatment liquid in a treatment tank so that the electrode plate extends along the longitudinal direction of the lead frame. In the processing device, a surface of the both electrode plates facing the lead frame is inclined near the center in the width direction of the lead frame and is gradually inclined toward both left and right long side edges in the width direction of the lead frame. An electrolytic surface treatment apparatus for a lead frame for electronic parts, which is formed on the above-mentioned middle-high surface.