JPH08181265A - Manufacture of lead frame - Google Patents

Abstract

PURPOSE: To improve precision of plating position and equalize the plating on the surface of a lead frame by removing a part of the first resist applied on the lead frame and applying first plating, and then, applying second resist and removing its one part, and applying second plating, and performing such like matters. CONSTITUTION: First resist 2 is applied on the surface of a molded lead frame, and a part of the first resist 2 applied on the optional part of the lead frame, and then first plating 5 is applied on the surface of the exposed lead frame. Next, the remaining first resist 2 is removed, and second resist 6 is applied on the optional section separate from the surface of the lead frame where the first plating 5 is applied. Next, a part of the second resist 6 corresponding to the section separate from the section from which the first resist 2 is removed, and second plating 9 is applied on the surface of the exposed lead frame, and then the remaining second resist 6 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lead frame manufacturing method, and more particularly to a plating method.

[0002]

2. Description of the Related Art A conventional lead frame manufacturing method (surface treatment method) will be described with reference to FIGS. As shown in FIG. 14, a jig called a sparger 111 was filled with the surface treatment liquid A 112, and the lead frame 10
Eject to 1. As shown in FIG. 15, the jetted A liquid 112 is applied to the lead frame 101 through a rubber mask 113 having an opening at a portion where surface treatment A is required. After that, the surface treatment liquid and the lead frame 10 are kept for a certain period of time.
A constant current is applied between 1 and 1, and the surface treatment A is performed on the surface of the lead frame 101 as shown in FIG. This is A
The plating 114 is completed.

Next, as with the A plating 114, the surface treatment B is performed on the lead frame 101. First, as shown in FIG. 17, the sparger 111 ′ is filled with the surface-treated B liquid 115 and jetted onto the lead frame 101. As shown in FIG. 18, the jetted B liquid 115 is applied to the lead frame 101 through a rubber-like mask 113 ′ having an opening where the surface treatment B is required. Thereafter, a constant current is applied between the surface treatment solution B and the lead frame 101 for a certain period of time, and the surface treatment B is applied to the surface of the lead frame 101 as shown in FIG. This completes the B plating 116. Through the above steps, a lead frame plated with A and B is completed.

[0004]

However, the conventional plating method has the following problems. That is, the plating position is determined after the lead frame is transferred in order to plate the lead frame, and this positioning is detected by the sensor. At this time, since a certain position of the processed lead frame is used as a reference, mechanical processing accuracy and positioning accuracy become problems.

Further, since the masks 113 and 113 'are made of rubber, distortion of the rubber occurs during plating. In addition, considering that the mask is processed in many places and the rubber-like material is processed, the processing accuracy of the mask becomes very poor.

Further, in the plating method using a sparger, the plating solution is ejected by pressure, and the uniformity of the plating on the surface of the lead frame cannot be guaranteed due to the difference in the way the plating solution hits the lead frame. In view of the above problems, it is an object of the present invention to improve the precision of the plating position and make the plating uniform on the lead frame surface.

[0007]

In order to solve the above-mentioned problems, in the method of manufacturing a lead frame of the present invention, a step of applying a first resist on the surface of the molded lead frame, and an optional step of the lead frame. Removing a part of the first resist applied to the portion, and applying a first plating to the exposed surface of the lead frame after removing a part of the first resist, Removing the remaining first resist after the first plating,
Applying a second resist to an arbitrary portion different from the surface of the lead frame on which the first plating is applied; and the second portion corresponding to a portion different from the portion where the first resist is removed. Removing a part of the resist of
A part of the resist is removed, and then a second plating is applied to the exposed surface of the lead frame; and a step of removing the remaining second resist after the plating treatment. To do.

[0008]

In the present invention, instead of the conventional sparger method using a mask, a lead frame is coated with a resist, and exposed and developed. As a result, the surface of the lead frame to be plated is exposed, and the portion not requiring plating is covered with the resist. In this state, the plating solution is not sprayed by the sparger but is immersed in the plating solution tank for plating, so that the surface of the plating can be made uniform.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a lead frame which is an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart showing the flow of the manufacturing process of the present invention. 2 to 12 are manufacturing process diagrams corresponding to each process of this flowchart. Hereinafter, each step of FIG. 1 will be described in correspondence with FIGS.

First, as shown in step A of FIG. 1 and FIG.
A negative resist 2 such as PMMA, which is the first resist, is applied to the entire surface of the molded lead frame 1 (in this case, either a frame molded by pressing or a frame molded by etching). For resist coating, a lead frame may be placed on a rotating mechanism of a spindle head used for resist coating on a wafer, and the resist may be sprayed onto both upper and lower surfaces of the frame without being rotated.

After applying the negative resist 2, as shown in step B of FIG. 1 and FIGS. 3 and 13, a mask 4 is used as a negative resist corresponding to the A-plated portion 3 which is the tip portion of the inner lead of the lead frame 1. Then, the surface of the lead frame 1 (the upper surface in FIG. 3) is exposed. Since it is a negative resist, the exposed portion is insoluble in the developing solution.

After the exposure, as shown in step C of FIG. 1 and FIG. 4, when the surface of the lead frame 1 covered with the negative resist 2 is developed, the A-plated portion 3 of the lead frame 1 is exposed.

After the A-plated portion 3 is exposed, the step D in FIG.
As shown in FIG. 1, the lead frame 1 is dipped in the A plating solution tank, and a constant current is applied between the A plating solution and the lead frame 1 for a certain period of time so that the A plating part 3 of the lead frame 1 is subjected to the first plating. A certain A plating 5 is formed.

After forming the A plating, as shown in step E of FIG. 1 and FIG. 6, the negative resist 2 remaining on the lead frame 1 is removed by a resist stripping solution or the like. In addition to the method using a stripping solution, the resist can be stripped using an asher. This completes the A plating process.

After peeling the negative resist 2, as shown in step F of FIG. 1 and FIG. 7, a negative resist 6 as a second resist is applied to the entire surface of the lead frame 1 plated with the A plating 5. This step may be the same as the step of applying the negative resist 2.

After applying the negative resist 6, as shown in step G of FIG. 1 and FIGS. 8 and 13, the negative resist corresponding to the B-plated portion 7 corresponding to the outer lead of the lead frame 1 is covered using a mask 8. Then, the entire surface of the lead frame 1 (both upper and lower surfaces in FIG. 8) is exposed. This step may be the same as the step B in FIG.

After the exposure, when the surface of the lead frame 1 covered with the negative resist 6 is subjected to a developing treatment as shown in step H of FIG. 1 and FIG. 9, the B-plated portion 7 of the lead frame 1 is exposed.

After the B-plated portion 7 is exposed, the step I in FIG.
As shown in 0, by immersing the lead frame 1 in the B plating solution tank and applying a constant current between the B plating solution and the lead frame 1 for a certain time, the B plating portion 7 of the lead frame 1 is subjected to the second plating. A certain B plating 9 is formed.

After the B plating 9 is formed, the J process of FIG.
As shown in, the negative resist 6 remaining on the lead frame 1 is removed by a resist stripping solution or the like. Besides this,
It is also possible to remove the resist with an asher as in the step E of FIG.

Finally, as shown in the step K of FIG. 1 and FIG. 12, the entire surface of the lead frame 1 including the surfaces of the A-plated 5 and the B-plated 9 is lightly etched with an A-plating stripper, and the entire surface of the lead frame 1 is etched. To wash.

As described above, in the lead frame manufacturing method of the present invention, the immersion method in the plating bath by coating the resist is used instead of the mask sparger plating method. As an effect of this, it is not necessary to consider the mask processing accuracy by the mechanical processing, the mask mounting accuracy, and the lead frame positioning accuracy, and only the mask displacement accuracy in the exposure process is improved, so the plating accuracy of the lead frame is improved. Further, since the lead frame is immersed in the plating solution bath instead of being applied to the lead frame by the sparger method, the lead frame surface can be plated under uniform conditions, and the plating can be made uniform.

[0022]

According to the present invention, the precision of the lead frame plating position is improved as compared with the prior art. Further, the lead frame surface can be plated under uniform conditions, and the plating can be made uniform.

[Brief description of drawings]

FIG. 1 is a flowchart of a manufacturing method of the present invention.

FIG. 2 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 3 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 4 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 5 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 6 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 7 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 8 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 9 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 10 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 11 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 12 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 13 is a manufacturing process diagram of the manufacturing method of the present invention.

FIG. 14: Conventional A plating process diagram

FIG. 15 is a view of a mask in the conventional A plating formation.

FIG. 16 is a lead frame at the end of A plating in the conventional manufacturing method.

FIG. 17: Conventional B plating process diagram

FIG. 18 is a view of a mask in the conventional B plating formation.

FIG. 19 is a lead frame at the end of B plating in the conventional manufacturing method.

[Explanation of symbols]

 1, 101 Lead frame 2, 6 Negative resist 3 A-plated part 4, 8, 113, 113 'Mask 5, 114 A-plated 7 B-plated part 9, 116 B-plated 111, 111' Sparger 112 A liquid 115 B liquid

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Tanabe 3500 Matsuoka, Oita-shi 3500 Toshiba Corporation Oita factory

Claims (1)

[Claims] 1. A first surface of a molded lead frame
The step of applying the resist, and the first part applied to an arbitrary part of the lead frame.
Removing a part of the resist, a step of removing a part of the first resist, and then performing a first plating on the exposed surface of the lead frame, and a step of remaining after the first plating. A step of removing the first resist, a step of applying the second resist to an arbitrary portion different from the surface of the lead frame on which the first plating has been applied, and a portion from which the first resist has been removed. Removing a part of the second resist corresponding to another part, and removing a part of the second resist, and then performing a second plating on the exposed lead frame surface, And a step of removing the remaining second resist after the plating treatment.