JPS6018993A - Method of producing hybrid type circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a hybrid circuit board in which discrete components such as leaded electronic/electrical components and leadless circuit elements are mounted and soldered, and the present invention relates to a method for manufacturing a hybrid circuit board in which leaded electronic/electrical components and other discrete components and leadless circuit elements are mounted and soldered. The purpose is to provide an effective circuit board that contributes to the

Hybrid molded boards that are equipped with leadless circuit elements that do not have lead wires and inexpensive small discrete components, and that greatly improve component mounting density, have been well known in the past. Discrete components such as electrolytic capacitors, which have leads (3) led out from the OD, can be manufactured using a board (on which a solder resist can be applied, leaving only the parts necessary for soldering the circuit pattern (5)).
Although the lead (3) is inserted into the through hole (4) to be drilled in 2) and mounted, the lower surface Uυ is brought into close contact with one substrate (2) to lower the mounting chamber C as much as possible, in order to further miniaturize the electronic device. Mounting methods have been attempted, but when mounting this type of discrete component (1) with the lower surface Ql) and closing the upper end of the through hole (4), the air inside the through hole (4) may sometimes leak when soldering. It has the disadvantage that it expands or the flux gas does not escape properly, causing a plowhole (7) in the nozzle (6), resulting in poor contact.

In addition, since the circuit pattern of this type of hybrid circuit board aimed at miniaturization is dense, even though the above drawbacks are eliminated, it is difficult to perform processing such as pressing or perforation on the board itself due to the risk of pattern breakage. This significantly impairs the degree of freedom in circuit design, and according to Utility Model Application No. 52-46261, spacers are mounted using an automatic machine such as an insert machine during the manufacturing process, and are also attached to the board to prevent displacement. Therefore, it had the disadvantage that productivity did not increase.

The present invention proposes a new manufacturing method that eliminates the above-mentioned drawbacks and improves productivity, and will be described in detail below.

FIG. 2 is a diagram showing the manufacturing process of the embodiment of the present invention, in which a circuit pattern is formed on both sides of the board by etching the copper foil, the portions necessary for soldering are measured, and the mounting location of the leadless circuit element is determined. Apply adhesive (121) to the mounting area of the discrete component, and apply adhesive (122) to the mounting area of the discrete component using screen printing or a micro-dispenser.
The adhesives (121) and (122) are insulating resin adhesives made of thermosetting resin, ultraviolet curing resin, etc. Next, the leadless circuit element α3) is attached to the adhesive (121).
If the main component of the adhesive composition is an epoxy-based thermosetting resin, it is held in a temperature range of 100°C to 150°C for about 30 minutes to 1 hour. Or if it is an ultraviolet curing resin, 5 to 10
A curing process is performed by irradiating ultraviolet rays with a mercury lamp for about seconds, and the leadless circuit element α3) is temporarily adhesively fixed to the substrate 00).

After the adhesive (122) is cured, cream solder Oa is printed on the same board side using a screen plate, and then leadless circuit element (I5) is printed on the board side opposite to the IJ-dress circuit element (03) mounting surface. mount and then heat at 200℃~
The cream solder Q4) is melted by maintaining the temperature in a temperature range of 250° C., and the leadless circuit element (15) is soldered to the board 00) by a so-called reflow soldering method.

Next, connect the lead (3) to the through hole (4) of the board QOI as shown in Figure 3.
) and mount the discrete component (1), but the component is mounted with the lower surface of the component in close contact with the adhesive (122), while the adhesive (122) is inserted into the through hole (
4) The thickness prevents the upper end from being blocked, and after mounting, at least the gap between the substrate and the lower surface of the component along the coating shape is used as a ventilation section that communicates with the outside through the through hole (4). It is disposed near the through hole (4) in order to close the lead (3), and has a shape that crosses between the through holes (4) as shown in the figure to prevent solder bridging between the leads (3) on the mounting surface.

The adhesive (122) is used during the temporary fixing process of the leadless circuit element 03), or when a thermosetting resin is used, the soldering of the leadless circuit element (I5) to be mixed with the leadless circuit element (I5) is applied in advance using the heat of the time. The discrete component (1) is hardened and therefore is not expanded by the mounting pressure and is mounted on the adhesive (122) having a thickness that is approximately the same as the coating thickness without being substantially bonded.

However, if the coating thickness is too low relative to the component diameter, the edge of the component outline will come into contact with the board surface and the ventilation condition will deteriorate. Therefore, in order to ensure a ventilation section that leads outward, the component outline shown in the dashed line in Figure 4 should be changed. If the coating is applied across the line, that is, in a shape extending from the bottom surface of the component to the outside of the external dimension, it is possible to limit the mounting height to the desired mounting height without depending on the coating thickness. As shown in the figure, the adhesive (122) may be divided to ensure an outward vent between the adhesives. Therefore, after mounting the discrete component (1), the board on which the leadless circuit element (13) is mounted. Solder the surface 7
421 side, and is dipped in a solder tank (16) to perform soldering.

The gas is guided outward as shown by the arrows shown in FIGS. 4 and 5, thereby preventing the occurrence of blowholes and creating a good agility for the hybrid molded circuit board.

The gist of the present invention is to prevent defects when soldering discrete components using an adhesive. However, since the adhesive is made of thermosetting resin, ultraviolet curing resin, etc. It is possible to perform curing treatment for temporary fixing of circuit elements to be bonded, or for bonding process, etc., and the type of adhesive or composition can be used for both processes, etc., if necessary. Can be done.

■ Since it is a method for coating irregularly shaped objects regardless of the mounting method using an insert machine, etc., an inexpensive screen printing method can be used, and this method allows for uniform coating within a range of approximately 50 μm to 1. This is possible, and the limited mounting height of discrete components can be easily accommodated by varying the coating thickness.

■ Because it is mounted after curing, there is no need to limit the shape or thickness of the coating, and it will not spread due to the pressure of the mount, and the spread coating will not block the lead insertion hole.
There is no possibility that the planned ventilation area will not be secured.

The present invention has the following effects, and is not limited to merely the steps of the embodiments.

That is, in the method for manufacturing a hybrid circuit board of the present invention, leads are led out from the first board surface and the bottom surface of the component in order to mount leadless circuit elements, and the discrete component is mounted on the side opposite to the first board surface. a step of applying a predetermined adhesive such as a thermosetting resin, an ultraviolet curing resin, etc. to the mounting location on the second substrate surface, and curing the adhesive on the first substrate surface side after mounting the leadless circuit element. and curing the adhesive on the second substrate surface side before mounting the discrete component, and mounting the discrete component with the lower surface of the component in close contact with the adhesive without substantially bonding the component. and a step of applying solder using the first substrate surface as a solder dipping surface.

As described above, according to the present invention, it is possible to contribute to cost reduction without deteriorating the degree of freedom and productivity of circuit design of a hybrid circuit board for the purpose of miniaturization, and it is possible to reliably solder discrete components. Its practical effects are extremely high, such as being able to avoid defects.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main part of the conventional example, Fig. 2 is an explanatory diagram of the manufacturing process of the embodiment of the present invention, Fig. 3 is a perspective view of the main part of the embodiment, Fig. 4 is an explanatory diagram of the main part of the embodiment, and Fig. 5 is an explanatory diagram of main parts of another embodiment. Explanation of symbols (1)...Discrete component (3)...Lead (10)...Board 01)...Bottom surface of component (121), (122)...・Adhesive (13)
, (+5)・・・Leadless circuit element patent applicant Aiwa Co., Ltd.

Claims (1)

[Claims] In order to mount a leadless circuit element, a thermosetting resin is applied to the mounting portion of the second substrate surface opposite to the first substrate surface, in order to mount a discrete component formed by leading out leads from the first substrate surface and the bottom surface of the component. a step of applying a predetermined adhesive made of resin, ultraviolet curing resin, etc.; a step of curing the adhesive on the first substrate side after mounting the leadless circuit element; and a step of curing the adhesive on the first substrate surface side before mounting the discrete component. After curing the adhesive on the surface side, the above disc 1.1
- mounting the component with the lower surface of the component in close contact with the adhesive without substantially bonding the component;
and a step of soldering the first board surface as a solder dip surface.