JPS6013305B2 - Manufacturing method of lead frame with support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a lead frame with a support.

Lead frames with supports are usually made by drilling necessary through holes such as device holes in an insulating synthetic resin film such as phenol resin, polyester resin, epoxy resin, or tetrafluoroethylene resin, and then attaching the synthetic resin film to a copper foil. Then, by etching unnecessary parts of the attached copper foil to obtain a lead frame pattern of steel foil, or by interposing an adhesive layer on the insulating resin film and attaching the copper foil. After drilling necessary through-holes such as device holes in the copper foil-covered resin film, the unnecessary parts of the copper foil are etched to obtain a lead frame pattern using the copper foil, or the necessary through-holes such as the device holes are etched. It is made by forming a metal lead frame pattern on a synthetic resin film with through holes formed therein using a haze deposition method.

However, in the conventional method described above, it takes time and effort to punch out necessary through holes such as device holes in the synthetic resin film using a punching die, and the synthetic resin film and copper foil are bonded together using an adhesive. It had to be done, and manufacturing it was not easy.

The present inventor has conducted research on a method for eliminating manufacturing complexity by omitting the process of punching out a synthetic resin film and the process of bonding between a synthetic resin film and copper foil in the production of conventional lead frames with supports. The gist of the present invention is an electrical device in which holes for silicon chips, device holes, etc. are opened on the back side of a thin metal plate by an image formatting method such as a printing method or a resist engraving method. a step of forming an insulating support, a step of providing a corrosion-resistant film on the surface of the metal board to cover the metal part that will become the lead frame, and then etching the metal thin plate to remove unnecessary metal parts. This is a method for manufacturing a lead frame with a support, which includes a step of removing the support to form a lead frame.

According to the manufacturing method of the present invention, a lead frame with a support can be easily obtained without requiring a step of punching out the support and a step of bonding the support and the steel foil.

The present invention will be described in detail below with reference to the drawings.

First, as shown in the first diagram, an electrically insulating support 4 having silicon chip mounting holes 2, device holes 3, etc. formed thereon is formed on the back surface of a thin metal plate 1 by an image forming method such as a printing method or a resist engraving method. Form. Here, it is a hole in which a silicon chip is placed. Next, the device hole 3 is a slot for inserting the inner lead, and after bonding the tip of the inner lead with the IC or BI chip, the device hole 3 is inserted so that a part of the lead portion that crosses the device hole 9 remains. This is necessary for cutting and removing the peripheral portion of the lead frame with a support along the line to form a leaded chip having a lead portion protruding from the support. Next, as shown in the second diagram, a corrosion-resistant film 5 is provided on the surface of the thin metal plate 1 to cover the metal portion that will become the wiring, and the exposed metal portion on the support side is protected with a corrosion-resistant varnish, paint, paste, etc. Protect with material 6. After that, the thin metal plate is etched to remove unnecessary metal parts as shown in Figure 3, and the corrosion-resistant film 5 is peeled off and the protective material 6 is removed as shown in Figures 4a and b. By forming the frame 7, a lead frame 8 with a support can be obtained.

In the above method of the present invention, when the support 4 is formed by a printing method, it is desirable to employ a conventionally known screen printing method, gravure printing method, etc. as the printing method.

In addition, inks used for printing include epoxy resins, acrylic resins, phenolic resins, vinyl chloride resins, pyrogenic resins, imide resins, amide resins, gelatin, casein, etc.; It is possible to use an ink with a composite composition in which organic and inorganic reinforcing substances are added to the support material 4.Furthermore, after printing, it is necessary to perform ultraviolet curing or heat treatment to form a film. When forming by the photoresist plate-making method, all commercially available photoresists can be used. 14, FR-15
(manufactured by Fuji Pharmaceutical Co., Ltd.) alone, and composite compositions in which organic and inorganic reinforcing substances are added to these can be used. FIG. 5 shows a wired chip formed using a lead frame with a support according to the manufacturing method of the present invention.

The chip 10 is placed in the silicon chip placement hole 2, the tips of the inner leads of the chip are bonded, and the peripheral portion of the lead frame with support is cut and removed along the device hole 3. As described above, according to the manufacturing method of the present invention, a lead frame with a support can be easily obtained without requiring the step of punching out the support and the step of bonding between the support and the copper foil.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 Prepare one side of an electroplated steel foil or rolled steel foil with a thickness of 0.035 mm and make it rough with a wire brush, and apply Solcon Primer #4 (manufactured by Kansai Paint) on the rough side. 0
．． 001~0.002 After applying to fence thickness 10 and 011
Heat treatment at oo0.

Thereafter, electrically insulating ink is passed through a silk screen plate and printed so as to form the outer peripheral shapes of silicon chip placement holes and device holes. For example, a vinyl chloride paste is used as the electrically insulating ink. After printing, a film is formed by heating at 150 to 190° C. for one batch. After heating, the thickness of the insulating film was 0.20 mm. Thereafter, the silicon chip mounting holes, device holes, and other exposed steel foil parts not to be etched are uniformly coated with shellac varnish, and dried by heat treatment at 80qC to 90q02. [
Composition of electrically insulating ink] Zeon 121 30th DO
P 15 Ferro stabilizer 25 Pigment
10 evening xylene
15 Afterwards, apply 0.0% of FR-14 (manufactured by Fuji Pharmaceutical Co., Ltd.) photosensitive liquid to the opposite side of the steel plate to which the insulation paste was applied.
The photoresist layer is coated to a thickness of 0.004 to 0.007 mm, exposed as a negative image, washed with water, and developed to form a positive lead frame-shaped photoresist layer.

After that, heat treatment is performed for 180 to 23 010 minutes, and then the exposed copper part is
oo) After etching with main etching solution and washing with water,
The shellac varnish film applied to the photoresist film, silicon chip mounting hole, and device hole is removed using a 90 to 95 qo solution of 5% NaOH. Example 2 A 0.035-thick Yanagi electroplated copper foil or rolled steel foil with one side roughened with wire brushing was prepared. On the other hand, apply an electrically insulating photosensitive material as shown below to a thickness of 0.15 mm.
~0.17 Apply to fence.

[Composition of electrically insulating photosensitive material] KMER (KODAK
) 100 polycalcium carbonate
30 tagarasu fiber powder
After drying naturally for 8 nights, use xylene for 8 nights, force dry for 10 minutes at 70-80 oo, apply a positive image mask such as the peripheral shape silicon chip mounting hole, device hole, etc., expose to ultraviolet-rich light, and develop as specified. Through the treatment, a support having an outer circumferential shape made of a photosensitive material, a hole for silicon chip placement, a device hole, etc., is obtained.

Thereafter, heat treatment is performed for 15 minutes at 120 to 140 degrees Celsius to solidify and adhere closely to the copper foil, and to form a film. Thereafter, the silicon chip mounting hole, the device hole, and other exposed copper foil parts not to be etched are coated with shellac varnish and dried by heat treatment for 80 to 90C020 minutes.
Next, apply G-90 (
A photosensitive solution (manufactured by Tokyo Ohka Chemical Co., Ltd.) is applied to a thickness of 0.004 to 0.007 mm, and a negative image is exposed and printed, followed by washing and development to form a positive lead frame-shaped photoresist layer.

After this, heat treatment was performed for 180 to 23 minutes, and then the exposed copper part was
Etched with main etching solution, washed with water, then 5%N
By removing the photoresist film and the shield varnish film with a 90-95q0 solution of aOH, a desired positive conductive lead frame pattern made of copper could be formed on the support made of the photosensitive material.

[Brief explanation of the drawing]

1 to 3 show a method for manufacturing a lead frame with a support according to the present invention. FIG. 3 is a cross-sectional view of the state in which a corrosion-resistant film is provided on the surface of the thin metal plate, FIG. 3 is a cross-sectional view of the state after etching, and FIGS. 4b is a plan view, and FIG. 5 is a sectional view of the leaded chip. Explanation of the symbols representing the main parts of the figure: 1...0 thin metal plate, 2...hole for silicon chip placement, 3...
・Device hole, 4...Electrical insulating support, 5.
... Corrosion-resistant film, 6... Protective material, 7...
... Lead frame, 8... Lead frame with support. Fig. 1 Fig. 2 Fig. 3 Sunmu Fig. Rudder Fig. 5

Claims (1)

[Claims] 1. Forming an electrically insulating support in which holes for silicon chips, device holes, etc. are opened on the back side of a thin metal plate by an image forming method such as a printing method or a resist plate making method;
A step of providing a corrosion-resistant film on the surface of the thin metal plate to cover a metal portion to become a lead frame, and a step of etching the thin metal plate to remove unnecessary metal portions to form a lead frame. A method for manufacturing a lead frame with a support.