JPH02126696A - Enameled wiring board and manufacture thereof - Google Patents

Abstract

PURPOSE:To reduce a cost and to rationalize a process by a method wherein a lead frame part and a substrate part are formed collectively by stamping an identical metal core and only a required part is coated with an enameled layer. CONSTITUTION:A metal core where a lead frame part 2 as shown as a white part and a substrate part 1 have been united is stamped by using a press. Several tens of sheets are connected as one series; their surface is treated, coated with glass and is baked. After this baking operation, a thin-film circuit is formed on the surface of an enameled layer. Thereby, it is possible to obtain a surface roughness required to form the thin-film circuit. The metal core in a part whose enameled insulation is not required is masked in advance so that the enamel- coated layer is not formed, or, after the enamel-coated layer has been formed, the enameled layer is removed; after that, the circuit is formed; a die bonding operation, a wire bonding operation and the like are executed. A circuit is formed on a substrate; a component is mounted; after that, a transfer molding operation is executed by using an epoxy resin or the like. Lastly, a part indicated by a one-dotted chain line is cut; one set of substrates provided with the lead frame is obtained.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an enameled wiring board that integrates a lead frame part and a board part.Furthermore, it is possible to perform enameling etc. of a series of many modules at once. This invention relates to a method for manufacturing an enameled wiring board.

[Prior Art] Conventionally, an alumina substrate and a lead frame (which were manufactured separately and integrated in an l-transfer mold) are used. In Fig. 2, 4 is an alumina substrate on which a circuit is formed. , IC chips, etc. are mounted.

The output terminal portion is connected to a lead frame using a bonding wire, and this is integrally sealed with epoxy resin or the like by transfer molding.

Also, instead of the alumina substrate of 4, 42 alloy (42% Ni,
Attempts have also been made to form an alumina layer on the surface of 58% Fe (58% Fe) using an ion blasting method or the like and use it as an insulating layer.

However, these wiring boards require a large number of steps, and since each board is manufactured individually, there are problems in that the number of steps increases and the manufacturing cost becomes extremely high.

(Problems to be Solved by the Invention) The purpose of the present invention is to eliminate the complexity of conventional wiring boards in which the circuit board and lead frame are held together and fixed together. Cost reduction and process rationalization can be achieved by using a enamel wiring board, which allows circuit formation and IC chip mounting work to be carried out continuously in the production of wiring boards (many boards at the same time). The purpose of the present invention is to provide an enameled wiring veneer and a method for producing the same.

(Means for solving the problem) Akashi Mizumoto and his colleagues conducted intensive research to solve the above problem. As a result, a set of metal cores with a pattern in which the lead frame part and the board part are integrally formed without enameling the lead frame separately is formed in a continuous form in a large number on the same metal plate. By creating an enamel wiring board with an enamel layer coated only on the necessary parts, the process was streamlined and the manufacturing cost could be reduced to 1 person, and the present invention was completed.

It is preferable that this enamel layer is made of alkali-free crystallized glass and has a smooth surface on which a film circuit can be formed.

As for the manufacturing method, a set of metal plates is formed by handling the lead frame and circuit board as one unit from the same metal core, and a continuous gold AI is formed in a series of multiple sets of the metal plates, followed by surface treatment, enameling coating, This is a method for manufacturing a hollow wiring board characterized by performing post-processes such as firing at the same time.

In the case of the present invention, a metal core that integrates a lead frame part and a board part, such as the white part in FIG. 42 alloy or 426 alloy is preferable because it also serves as a material.

Dozens of these pieces are assembled in series and subjected to surface treatment (degreasing, sandblasting), glass coating, and firing.

Is it special I as a glass frit here? 3567364
ad as shown in the 3rd bulletin.

Crystallized glass containing MgO, B 2 O, and S+02 is preferably used.

Since a film circuit is formed on the surface of the enamel layer after firing, it is desirable to use glass particles having an average particle diameter of 0.5 to 4 μm. As a result, a surface roughness Rt of 0.5 to 1 μm, which is necessary for forming a thin film circuit, can be obtained.

For unnecessary parts of this enamel insulation, mask the metal core in advance to prevent the formation of the enamel coating layer, or remove the enamel layer by sandblasting etc. after forming the enamel layer rG Ffi to form this invasion circuit. Performs die bonding, wire bonding, etc.

After circuit formation and component mounting on the board, transfer molding is performed using epoxy 81 resin or the like on the area surrounded by the dotted line in FIG.

Finally, a set of lead frame-attached substrates (9) are obtained by cutting the portions indicated by the dashed lines in FIG.

In FIG. 1, 1 is a substrate, 2 is a lead frame, and 3 is a portion where the enamel is peeled off to expose the metal. The dotted line shows the transfer mold, and the dotted chain line shows the final cutting part.

In FIG. 2, 4 is alumina 4 roots, 5t is an IC chip, 6 is a conductor circuit, 7 is a bonding wire, 8 is a lead frame, and 9 is a transfer mold.

FIG. 3 shows an example of a conventional lead frame.

Reference numeral 10 indicates a planned board setting location, and reference numeral 11 indicates a lead frame.

(Example) The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited to these embodiments.

A continuous board with a lead frame was prepared by punching out a series of 30 sheets with the pattern shown in FIG. 1 from a 42 alloy plate having a thickness of 0.27F, leaving a white 1-side portion.

After degreasing this continuum by alcohol washing and sandblasting, BaO-MgOB203-8
i 02 series alkali-free crystallized glass with average particle size t! i! Glazed with 0.8 μm glass frit, 850
Calcined at ℃. The enamel in the area between the dashed line and the dotted line in FIG. 1 was removed by sandblasting.

Circuits were formed on the enamel board, components such as bare chips were mounted, and wire bonding was performed between the board terminals and the lead frame (length, the part inside the dotted line was made using epoxy ()).
] Transfer molding was performed using oil for sealing.

Thereafter, each piece was cut to obtain an enameled wiring board in which a lead frame portion and a circuit board portion were integrally formed.

(Effects of the Invention) As explained above, the wiring board according to the present invention has one set of metal cores with a pattern formed by integrally punching the lead frame part and the board part, and many sets of these metal cores are connected in a continuous form. Since the wiring board is formed on the same metal plate and only the necessary parts are coated with enamel, it is possible to continuously obtain many sets of enamel wiring boards at the same time. Therefore, the I culm is simplified, and the cost can be significantly reduced to 1.

In addition, the surface of the enamel insulating layer has a surface roughness of Rt-0.5 to 1 μm.
Since it has a smooth surface condition, it is possible to form fine-pattern thin film circuits, and it also has excellent internal strength, electromagnetic shielding properties, and heat dissipation properties, making it extremely useful as an F11 substrate.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a set of metal frames in which a lead frame and a substrate of the present invention are integrated. FIG. 2 is a sectional three-dimensional view showing the relationship between a conventional plastic-sealed small alumina substrate and a lead frame. FIG. 3 is a plan view showing an example of a conventional lead frame.

Claims (3)

[Claims] 1. This enamel wiring board is made by punching out the lead frame part and the board part as one piece from the same metal core, and coating only the necessary parts with an enamel layer. 2. A set of metal plates is formed by punching out a lead frame part and a circuit board part from the same metal core as one unit, and multiple sets of these metal plates are formed into a series of continuous metal plates, which are then subjected to surface treatment, enameling coating, and firing. A method for manufacturing an enameled wiring board, characterized in that post-processes such as the following are performed simultaneously. 3. Claim 1: The enamel layer is made of alkali-free crystallized glass and has a smooth surface capable of forming a thin film circuit.
Enamel wiring board described.