JPH04364768A - Insert molding method - Google Patents

Abstract

PURPOSE:To realize a molding method wherein a required insert molding operation can be performed in a state which has avoided completely that a resin for molding use is applied to the face of a lead terminal which is extracted. CONSTITUTION:In an insert molding method, a lead terminal 2 is extracted and arranged along an opening face 1a at the inside of a first metal mold 1 one end of which is opened, a second metal mold 3 is arranged so as to bring a corresponding opening face 3a face to face with the opening face 1a in the first metal mold 1, and a resin for molding use is injected into a metal mold to perform a molding operation. The molding method is featured in such a way that a protrusion part 3b which changes the lead terminal 2 locally into a recessed face 2a is formed in the opening face 3a at the inside of the metal mold from which the lead terminal 2 is extracted. It is possible to wholly prevent or eliminate a phenomenon that the resin for molding use injected into the metal mold flows out or creeps along the face of the lead terminal 2 extracted along the opening face 1a in the metal mold 1. Consequently, it is possible to obtain an insert molded product wherein the resin which obstructs a connection by a plating treatment, a soldering operation, a welding operation, a bonding operation or the like is not applied to the face of the lead terminal 2 which is extracted.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert molding method, and more particularly to an insert molding method for resin molded products from which lead terminals are derived, such as for packages.

0002

2. Description of the Related Art For example, a multi-chip module has a structure in which it is sealed in a resin package from which lead terminals are led out in order to maintain and exhibit stable functions or provide highly reliable functions. A resin package from which this type of lead terminal is derived is generally manufactured by the following insert molding method. Figure 4
(a) and (b) are cross-sectional views schematically showing essential parts of this embodiment. First, a lead terminal 2 is guided and placed along an opening surface 1a in a first mold 1 having an open end. do. Next, the second mold 3 is placed with the opening surface 3a corresponding to the opening surface 1a of the first mold 1 facing each other, and after combining the required insert molding molds (FIG. 4(a) ))
, attach it to a molding machine, inject molding resin into the mold, and perform the required insert molding. After that, the mold is removed from the molding machine and disassembled into the first mold 1 and the second mold 3, and the insert molded product is taken out from the mold to form the required shape from which the lead terminal 2 is drawn out. A resin package was obtained (Figure 4(b)). In addition, in FIG. 4(b), 4 is a molded resin layer in which a part of the lead terminal 2 is embedded.

0003

[Problems to be Solved by the Invention] However, the following inconvenient problems are recognized in resin packages obtained by the above-mentioned insert molding method. That is,
In the insert molding method, the opening surface 1a of the first mold 1 that is in contact with the lead terminal 2 to be led out is formed in a groove shape, but the opening surface 3a of the second mold 3 that is in contact with the lead terminal 2 is formed in the shape of a groove. When unevenness is likely to occur between the lead terminal 2 and the lead terminal 2, or when the pressure is insufficient, a part of the molding resin injected into the mold flows out, causing the opening surface 3a of the second mold 3 to flow out. It is often the case that the insulating layer 5 is formed by adhering to two surfaces of the lead terminals that are brought out in contact with the sides. By the way, the two surfaces of the lead terminals that are led out are plated if necessary and used as connection terminals, or used (used) for electrical or mechanical connections by soldering, welding, bonding, etc. However, due to the adhesion and presence of the insulating layer 5, cutting is sometimes required, which poses a problem in that the workability of this type of connection is significantly impaired. On the other hand, in order to prevent part of the molding resin from flowing out or seeping out, one way is to increase the pressure on the mold, but this increases the size of the molding machine and complicates the molding operation, resulting in cost problems. There are practical problems.

The present invention has been made in response to the above-mentioned circumstances, and provides a molding method that can perform the required insert molding while completely avoiding adhesion of molding resin to the lead terminal surface. For the purpose of providing.

[0005]

[Means for Solving the Problems] In the insert molding method according to the present invention, a lead terminal is placed in a first mold having an opening at one end and led out along the opening surface of the first mold. A second mold is placed with the opening surfaces corresponding to the molds facing each other,
In an insert molding method in which molding resin is injected into a mold and molded, a protrusion that locally concaveizes the lead terminal is provided on the inner mold opening surface from which the lead terminal is led out. Features.

[0006]

[Operation] According to the insert molding method according to the present invention, corresponding to the lead terminal led out along the opening surface of the mold,
Insert molding is performed in a state where the opening is temporarily partitioned by a protrusion provided near the inner side of the opening. In other words, the phenomenon in which the molding resin injected into the mold flows out or oozes out along the lead terminal surface led out along the opening surface of the mold is completely prevented or eliminated. Therefore, it is possible to obtain an insert molded product in which there is no resin adhesion on the lead terminal surface that would inhibit connection by plating, soldering, welding, bonding, or the like.

[0007]

Embodiments An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3.

FIGS. 1(a), (b) and (C) are cross-sectional views schematically showing essential parts of an embodiment of the insert molding method according to the present invention. A lead terminal 2 is placed in the mold 1 so as to extend along the opening surface 1a. Next, the second mold 3 is placed so that the opening surface 3a corresponding to the opening surface 1a of the first mold 1 faces each other, and the required insert molding molds are assembled (FIG. 1(a)).
). The second mold 3 used here has an opening corresponding to the lead terminal 2 led out along the opening surface 1a of the first mold 1, as shown in an enlarged view in FIG. 1(b). A protrusion 3b is provided inside the surface 3a. Therefore, the first
The opening surface 1a of the mold 1 and the opening surface 3a of the second mold 3
The protrusion 3b is set in a wedge-like shape into the surface of the lead terminal 2 led out between the two.

[0009] Thereafter, the above-mentioned combined insert molding mold is mounted on a molding machine, a required molding resin is injected into the mold, and insert molding is performed by conventional means. Next, the mold is removed from the molding machine, disassembled into the first mold 1 and the second mold 3, and the insert molded product is taken out from inside the mold, so that the lead terminal 2 is drawn out as required. A resin package is obtained (Figure 1(c)).
. In FIG. 1(c), 2a is a recess formed in the lead terminal 2 by the insert molding, and 4 is a molded resin layer in which a part of the lead terminal 2 is embedded.

FIG. 2 is a perspective view showing a main part of a usage example of a package for a hybrid integrated circuit molded by the above-mentioned insert molding method. A hybrid integrated circuit board 7 on which necessary electronic components are mounted is mounted and arranged in the inside of the hybrid integrated circuit board 6, and connected to the lead terminals 2 by bonding wires 8. As can be seen from this usage example, the surface of the lead terminal 2 that penetrates the side wall and is led out has a recess (groove) formed by the wedge-shaped bite of the protrusion 3b provided on the opening surface 3a of the second mold 3. ) 2a is formed, and the recess (groove) 2
Resin adheres to the two surfaces of the lead terminals on the inside (side wall side) of a, forming the insulating layer 5, but since there is no resin adhering to the tip side, wire bonding is possible without the need for any pretreatment. I was able to accomplish this.

[0011] In the above embodiment, the protrusion 3b, which forms a recess on the surface of the lead terminal 2 by forming a concave portion on the surface of the lead terminal 2 by forming a secondary partition for the injected resin during insert molding, is shown in cross-section, for example, in FIG. As shown in the figure, it may be semicircular or spherical. The point is that as long as it digs in even slightly to form a recess 2a on the surface of the lead terminal 2 and serves to prevent the injected resin from flowing out or seeping along the surface of the lead terminal,
Its shape is not particularly limited. In other words, the shape and size of the protrusion 3b can be selected and set as appropriate depending on the fluidity of the molding resin to be injected, the pressure during insert molding, and the like.

0012

[Effects of the Invention] As can be seen from the above description, according to the insert molding method of the present invention, a lead can be produced in which adhesion (adhesion) of resin components to the lead terminal surface led out from the molded resin layer is completely avoided. Molded products with terminals can be easily obtained. In other words, when insert molding a package for a hybrid integrated circuit device with lead terminals, it is possible to perform reliable (highly reliable) ultrasonic wire bonding, soldering, welding, etc. without any processing. It is possible to manufacture packages for hybrid integrated circuit devices. Therefore, being able to avoid resin adhesion to the lead terminal surface not only does not impair the appearance of the molded product itself, but also allows operations such as pre-treatment or pre-processing of the lead terminal surface prior to wire bonding etc. Not only is this unnecessary, but damage to the lead terminal surface is also avoided, and it can be said that it brings many practical advantages.

[Brief explanation of drawings]

FIG. 1 schematically shows an embodiment of the insert molding method according to the present invention, in which a is a cross-sectional view of a main part showing a state in which a lead terminal is led out and placed in a mold, and b is a cross-sectional view of a main part showing a state where a lead terminal is led out and placed in a mold. FIG. 3 is an enlarged cross-sectional view showing the state of the opening surface of the mold corresponding to the lead terminal, and c is a cross-sectional view of the insert molded product.

FIG. 2 is a perspective view showing a main part of a package manufactured by the insert molding method according to the present invention with a hybrid integrated circuit board attached thereto.

FIG. 3 is an enlarged sectional view showing the state of the opening surface of another mold used in the insert molding method according to the present invention.

FIG. 4 schematically shows an embodiment of the conventional insert molding method, in which a is a cross-sectional view of the main part showing a state in which lead terminals are led out and placed in the mold, and b is a cross-sectional view of the insert molded product. figure.

[Explanation of symbols]

Claims (1)

[Claims] 1. Lead terminals are arranged in a first mold having an open end along the opening surface, and the opening surface corresponding to the opening surface of the first mold is opposed to the second mold. In an insert molding method in which a mold is placed and a molding resin is injected into the mold for molding, a protrusion that locally makes the lead terminal concave is provided on the inner mold surface from which the lead terminal is led out. An insert molding method characterized by: