JPH09162346A - Novel lead frame - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make plated parts and lead wires thinner by bringing each device- side metal plated part and a substrate-side metal plated part into contact on the surface of a molded article independently respectively or into contact with the surface of the molded article independently respectively or into connection via a conductor passing through the molded article. SOLUTION: A device-side metal plated part 4, in contact with each contact of an electronic device 2 main body of an IC chip 1 independently, and a substrate-side metal plated part 5, in contact with each contact provided on the substrate 6 side, are brought in contact on the surface of a molded article independently respectively, or in contact with the surface of the molded article independently respectively. Alternatively, they are connected to contacts of the substrate 6 via a lead frame 3 passing through the molded article of the IC chip 1. Thus, respective plated parts 4, 5 can be made thinner, and lead wires can be made thinner. Therefore, the complicated IC chip 1 or lead frame 3 for an LSI having many pins can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is a novel lead frame.
And a method for manufacturing an electronic device using the lead frame.

[0002]

2. Description of the Related Art A lead frame is a component that supports an IC (integrated circuit) and functions as a lead wire connected to a substrate, and therefore has a sufficient strength and a thermal expansion comparable to that of a chip. A good conductor material having a coefficient is used. Therefore, the conventional lead frame has a metal, such as copper, iron-nickel, and iron-based metal that forms the lead wire portion that is stamped from a metal plate and is formed by etching, and is centered. The mounted and connected ICs are both made of resin and solidified, and the foot portion protruding from the resin is inserted into the socket of the board for use.

[0003]

With the development of electronic devices, the structure of electronic devices has become complicated, and IC contacts and leads have become complicated.
The number of dframes has increased. However, conventional
In the dframe, the metal part itself, which is selected from a material having a coefficient of thermal expansion similar to that of the chip, gives strength, so the metal needs to have a certain thickness, and therefore, the stamping or etching of the metal plate is required. -When manufacturing a conductor part of a dframe, since a considerable width is required for one lead wire portion, a lead wire which can be put out from the periphery of an IC having a size of a certain square centimeter. Is limited, and, for example, in the case of etching, only a groove having a plate thickness of 1: 1 can be formed.

[0004]

The inventor has found that an increased number of
It has been discovered that a lead frame that enables a wire to be made possible by applying metal plating to a three-dimensional molded product of plastic whose physical properties such as thermal expansion coefficient are appropriately selected. Achieved the invention.

The present invention is applied to each of a plurality of metal contacts of a pattern having an electronic device body such as an IC or LSI chip, and to a plurality of metal contacts of another pattern provided on a substrate. A lead having metal plating on a molded article of low coefficient of thermal expansion plastic material for connection.
A dframe that independently contacts the respective contacts of the electronic device body such as the IC or LSI chip and, if necessary, guides the conductor from the contact location to a certain position on the surface of the molded product. Contact / lead wire pattern device-side metal-plated portion (for example, on the upper surface of a plate-like object) for independently contacting each contact provided on the substrate and its contact if necessary. In order to guide the conductor from a place to a certain position on the surface of the molded article, each has a metal plating portion on the substrate side of the contact / lead wire pattern (for example, on the side surface or the bottom surface of the plate-like object), The device-side metal-plated part and the substrate-side metal-plated part of the above are independently contacting each other on the surface of the molded product, or are independently adhered to the surface of the molded product or guided through the molded product. Characterized in that it is connected via a re made from the molded article with the metal plating low thermal expansion plastics material - Dofure - arm, and such a re -
A substrate and method for using a dframe.

Electronic Device Main Body All electronic devices provided on a substrate and having a plurality of contacts are electronic devices that can be supported and connected by the lead frame of the present invention.

Kind of Metal to be Plated and Plating Method Since the structural strength of the lead frame of the present invention is provided by the plastic material, the plated portion is not required to have particularly strict physical properties. Therefore, copper plating or nickel plating can be used. Further, as to the conductivity, it is possible to improve the conductivity and the rust preventive property by further partially or entirely applying gold plating. For the method of plating a precision pattern on a flat object surface,
For example, it is described in, for example, FIGS. 7 and 8 of the applicant's JP-A-3-207870. Regarding the method of three-dimensionally plating, a resist layer forming method in which a resist is sprayed onto a precision pattern by inkjet from multiple directions and a resist layer forming method in which a photosensitive resist is exposed through an image through multiple directions are disclosed. Japanese Patent Application No. 7-25999
There is a method of plating by utilizing the method of Japanese Patent No. There is also a method of drawing with a laser for image formation for plating. Further, when using electroless plating, a plastic plate is subjected to resin etching to form a rough surface, a resist is applied to the entire surface, and the resist is applied only to the portion where a metal layer is to be formed by exposing an image and exposing. To prevent it from existing, attach a catalyst, perform electroless plating to remove the resist, and if necessary, apply electrolytic plating on the formed plating, and apply the resist to the entire surface of the plastic plate Make sure that the resist does not exist only in the part where the metal layer is to be formed by exposure, etc., and then the resin is etched to form a rough surface, the resist is removed, and the catalyst is attached to the rough surface to leave only that part. There is a method in which electrolytic plating is performed and, if necessary, electrolytic plating is performed on the formed plating (see Japanese Patent Application No. 7-26000 (Japanese Patent Application Laid-Open)). .

Usable Low Thermal Expansion Coefficient Plastic Material The plastic material must have sufficient strength and a low thermal expansion coefficient comparable to that of an IC chip in order to exert the function of supporting the main body of the lead frame electronic device. There is. Suitable for such a condition is a liquid crystal polymer filled or unfilled with glass or an inorganic filler. As an example of such a liquid crystal polymer, a wholly aromatic polyester made from p-hydroxybenzoic acid, p, p'-biphenol, and terephthalic acid is a thermoplastic resin and has flexibility in design and processing economy. It has a high melting point, high solder heat resistance, flame retardancy, high elasticity and vibration damping characteristics, and has a small shrinkage factor and linear expansion coefficient during molding and is suitable for supporting IC chips. Excellent in chemical resistance and solvent resistance,
It has the advantages that it is thin, has excellent fluidity, and is resistant to burr, making it suitable for molding precision parts and being tough.
Most suitable for plastic material of dframe. The plastic material can be mass-produced by molding in a mold extremely easily and at low cost.

Top and Side Covering If desired, the top and side surfaces of the lead frame may be covered for protection.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The lead frame of the present invention will be described with reference to the drawings. For simplicity, FIG. 1 is a bottom view of an LSI chip 1 having a large number of contacts, and FIG. 2 is a top view of a lead frame of the present invention in which a liquid crystal plastic plate is plated. No. 3 of the present invention, which is plated
The lower surface of the dframe and FIG. 4 are used as the substrate. The upper and lower surfaces of FIG. 2 and the lower surface of FIG. 3, which are in contact with the sides in the longitudinal direction, are continuously provided on the side surfaces (not shown) so that the corresponding plated portions are connected to each other. Further, in the above case, the lower surface is not provided with a plated portion, and as shown in FIG. 5, the substrate is provided with a recess for accommodating the lead frame, and the side surface of the recess is provided with a contact of the substrate to provide a lead frame. It is possible to bring the plated portion on the side surface of the hole into contact with the contact on the side surface of the recess. In addition, the technique of connecting the plated portion on the upper surface and the plated portion on the lower surface by a conductor that penetrates through the plastic molded product is well known. With this technique, after coating the portion that does not need to be exposed with resin, the plated surface Most of the
A dframe can be realized.

The chip 1 is placed at a designated position on the lead frame 3 and each of the contacts 2 of the chip 1 is attached to the lead frame 3.
When the print soldering is applied to each of the parts of the upper surface of the plate near the center of the plated part 4, the chip 1 and the lead frame 3
And are bonded and their respective contacts are connected.

When each of the plated portions 5 on the lower surface of the lead frame 3 is printed and soldered to each of the contacts 7 of the substrate 6, the lead frame 3 is adhered to the substrate and the lower surface of the chip 1 is attached. Each of the contact points 2 is connected to the contact point 7 of the substrate 6 via each of the lead wires of the lead frame.
Connected with each other. Positioning at the time of adhesion by print soldering can be achieved by a conventional automatic machine, robot or the like. If the substrate is provided with a positioning means such as a recess for accommodating the lead frame, the positioning can be easily performed manually.

[0013]

【The invention's effect】

1. The structural strength of the lead frame supporting the IC chip depends on the plastic material and not on the plated portion, so that the plated portion can be thin and the lead wire can be thin. . Therefore, a lead frame for an LSI having a large number of complicated legs can be realized.

2. 2 and 3 show the same size and shape as the conventional lead frame for the purpose of explanation, but the area occupied by the substrate can be made substantially the same as the area of the chip. Therefore, even when supporting a chip with a small number of legs, it can exert its power in downsizing (downsizing) of electronic devices.

3. The shape may be a simple flat plate, and it does not require a small hole to insert the foot (pin), so the plastic part is easy to manufacture, and the metal part is also formed by plating based on the image of the photographic film. No need for complicated metal processing, and the manufacturing cost is low.

[Brief description of the drawings]

FIG. 1 is a bottom view of a chip having a contact metal exposed portion on the bottom surface.

FIG. 2 is a top view of the lead frame of the present invention for centering the chip of FIG.

FIG. 3 is a bottom view of the lead frame of the present invention.

FIG. 4 is a substrate having contacts corresponding to the plated portion on the lower surface of the lead frame in FIG.

FIG. 5 is a perspective view showing a specific example of the present invention when the lead frame is fitted into the recess of the substrate.

Claims (3)

[Claims] 1. A plurality of metal contacts of a pattern having an electronic device body such as an IC or LSI chip, and a plurality of metal contacts of another pattern provided on a substrate. A lead frame having a metal plating on a molded product of a low coefficient of thermal expansion plastic material for the purpose of
Independent contacts for independently contacting each contact of the electronic device body such as the IC or LSI chip, and for guiding the conductor from the contact location to a certain position on the surface of the molded product, if necessary. / A conductor having a metal plating portion on the device side of the lead wire pattern for independently contacting each contact provided on the substrate and, if necessary, from the contact location to a position on the surface of the molded product Independent contact / lead wire pattern has a substrate-side metal-plated portion, and the device-side metal-plated portion and the substrate-side metal-plated portion are independently formed on the surface of the molded product. Low thermal expansion with metal plating, characterized in that they are in contact with each other, or are independently adhered to the surface of the molded product or are connected via a conductor that passes through the molded product. Lead frame made of molded plastic material. 2. A substrate having a lead frame loading portion without pin holes for loading the lead frame according to claim 1, which does not use pins. 3. An electronic device body such as an IC or LSI chip having an upper surface of the lead frame according to claim 1, wherein the upper surface has a device-side metal plating portion and the lower surface has a substrate-side metal plating portion. A method of manufacturing an electronic device, comprising adhering and connecting with print solder, and adhering and connecting the lower surface to a substrate with print solder.