JPH03192794A - Mounting of electrical circuit component and ic package - Google Patents

Abstract

PURPOSE:To enable outer leads small in pitch to be easily connected to the conductor of a printed wiring board by a method wherein a connecting member provided with conductive members insulated from each other is interposed in an insulating holder, and the outer leads of an IC package are soldered to the conductor of the printed wiring board. CONSTITUTION:One end 2a of a conductive member 2 of an electrical connecting member 1 is connected by thermocompression bonding to the end of an outer lead 21 plated with tin 22 to transfer the conductive member 2 to the outer lead 21. Then, the conductive member 2 is dipped into a soldering bath to plate the other end 2b of the conductive member 2 with a solder 23, an IC package is mounted on a printed wiring board 24, and then the end 2b of the conductive member 2 is connected to the conductor 25 of the printed wiring board 24 by reflowing solder by heating. As mentioned above, the conductive members of an electrical connecting member are made small in pitch, whereby a fine soldering not attainable by a past printing method can be realized.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to electronic component mounting technology, and in particular to a mounting method that can connect the outer leads of an IC package and the conductors of a printed wiring board with high density, and a method for connecting the outer leads to the outer leads. The present invention relates to an IC package to which members are transferred.

[Conventional technology]

In an IC puff cage in which an IC chip is sealed with resin, the outer leads, which are the lead portions exposed outside the resin after sealing, are generally connected to the conductors of the printed wiring board by soldering. The following two methods are known as methods for connecting the two by soldering.

FIG. 4 is a schematic diagram showing the process of the first conventional connection method. After inserting the outer leads 43 of the IC package (not shown) into the plurality of through holes 42 (FIG. 4(a)) formed in the printed wiring board 41 (FIG. 4(b)).
), manual or automatic soldering is performed to connect the outer lead 43 to the conductor 45 of the printed wiring board 41 with the solder 44 (FIG. 4(C)).

FIG. 5 is a schematic diagram showing the process of the second conventional connection method. A solder paste 4 is applied in advance to a wiring pad 46 (FIG. 5(a)) which is a conductor to be connected on a printed wiring board 41.
7 (Fig. 5 (bl), outer lead 43).
The IC package 48 is mounted on the printed wiring board 41 so that it is in contact with the solder paste 47 in FIG.
), the solder paste 47 is melted by reflow heating to connect the outer lead 43 and the wiring pad 46 (fifth
Figure (d)).

[Problem to be solved by the invention]

However, in order to connect the two using the first conventional connection method, the distance between adjacent outer leads must be at least one fin, and even with the second conventional connection method, the distance is 0.4 * ■The above is necessary. As described above, conventional connection methods have problems in that there is a limit to the spacing between adjacent outer leads, and it cannot support IC chips with multi-pin configurations where the spacing between outer leads is narrow, making high-density packaging impossible. Ta.

By the way, it has been proposed to electrically connect electric circuit components to each other using an electrical connection member having a structure in which a plurality of conductive members are insulated from each other in an insulating holder (
JP-A No. 63-222437 JP-A No. 63-2242
Publication No. 35, etc.).

FIG. 6 is a schematic diagram showing electrical connections between electrical circuit components using such electrical connection members, and in the figure, 31 is an electrical connection member, and 32 and 33 are electrical circuit components to be connected. show. The electrical connection member 31 connects a plurality of conductive members 34 made of metal or alloy, and connects each conductive member 34 to each other.
It is configured to be electrically insulated and provided in a holder 35 made of an electrically insulating material, with one end 38 of the conductive member 34 exposed to one electric circuit component 32 side, and the other end 39 of the conductive member 34 exposed to one side of the electric circuit component 32. It is exposed on the other electric circuit component 33 side (
Figure 6(a)). The connecting portion 36 of one electric circuit component 32 and the conductive member 34 exposed on the side of the electric circuit component 32
One end 38 is alloyed to connect the two, and the connecting portion 37 of the other electric circuit component 33 and the electric circuit component 33 are connected.
The two are connected by alloying the other end 39 of the conductive member 34 exposed to the side (FIG. 6(b)).

In such electrical connection members, by making the size of the conductive member finer, it is possible to miniaturize the connection part of the electric circuit components, increase the number of connection points, and increase the number of connection points between the electric circuit components. High-density connections are possible.

The present invention has been made in view of the above circumstances, and it is possible to connect an I.
Short pinch (
A mounting method for electrical circuit components that can easily connect an outer lead (0.4 mm or less) to a conductor of a printed wiring board, and a method that can be used for this mounting method and has one end plated with solder. An object of the present invention is to provide an IC package in which the other end of a conductive member is transferred to an outer lead.

[Means to solve the problem]

A method for mounting an electric circuit component according to the present invention includes a step of connecting an outer lead of an IC package and a conductor of a printed wiring board by soldering, the method comprising: a holder made of an electrically insulating material; one exposed end of the conductive member of an electrical connection member comprising a plurality of conductive members provided in the holding body insulated from each other, both ends of which are exposed from both sides of the holding body; a step of plating the other exposed end of the conductive member with solder; and a step of connecting the conductive member and the conductor of the printed wiring board by soldering. Particularly, an IC package according to the present invention is characterized in that the IC package has an outer lead, and includes a holder made of an electrically insulating material, and a holder insulated from each other in the holder,
One exposed end of the electrically conductive member of the electrical connection member, which is composed of a plurality of electrically conductive members whose both ends are exposed from both surfaces of the holder, is transferred to the outer lead, and this electrically conductive member The other exposed end is coated with solder.

[Effect]

In the mounting method of the present invention, one exposed end of the conductive member is transferred to the outer lead, the other exposed end of the conductive member is plated with solder, and the conductive member is heated and reflow soldered. and the conductor of the printed wiring board to connect the outer lead and the conductor. Then, by reducing the pitch of the conductive members in the electrical connection member, fine soldering that is impossible with solder paste printing becomes possible.

〔Example〕

FIG. 1 is a sectional view of an electrical connection member used in the mounting method of the present invention. The electrical connection member 1 includes a plurality of conductive members 2 made of, for example, gold, arranged in a holder 3 made of polyimide resin such that the conductive members 2 are electrically insulated from each other. Both ends 2a of the conductive member 2
, 2b are exposed from the holder 3.

Next, an example of a method for manufacturing an electrical connection member having such a structure will be described based on FIG. 2 showing the process.

First, polyimide resin 12, which will serve as a holder, is applied onto the prepared copper plate 11 together with an adhesion aid using a spinner.
Figure 2(a)). In consideration of the decrease in film thickness due to curing, the film thickness of the polyimide resin 12 applied is set to be thicker than the desired film thickness of the holder in the electrical connection member to be manufactured. Next, the polyimide resin 12 is irradiated (exposed) with light through a negative photomask (not shown) having a predetermined pattern, and then developed. In this example, the polyimide resin 12 remains in the exposed portions, and the polyimide resin 12 is removed in the unexposed portions by development processing to form holes 13. Thereafter, the temperature is raised to cure the polyimide resin 12 (FIG. 2(b)).

Next, the copper plate 11 that has been treated in this manner is immersed in an etching solution to perform etching. A portion of the copper plate 11 near the hole 13 is etched away, and a recess 14 communicating with the hole 13 is formed in the copper plate 11 (FIG. 2(C)). Using the copper plate 11 as a common electrode, gold electroplating is performed, and the holes 13. The recess 14 is filled with gold 15 which becomes a conductive member (FIG. 2(d)). Finally, the copper plate 11 is removed by metal etching to produce an electrical connection member l as shown in FIG.

FIG. 3 is a schematic cross-sectional view showing the process of the mounting method of the present invention. Reference numeral 21 indicates an outer lead exposed from the IC package (not shown), and the surface of the outer lead 21 on the side that contacts the conductive member 2 is plated with tin 22 (
Figure 3(a)). Tin plating is applied to the surface of the outer lead 21 so that the conductive member 2 can be transferred to the outer lead 21 at a low temperature. Next, one end 2a of the conductive member 2 of the electrical connection member 1 is thermocompression bonded (at a temperature of about 300°C) to the end of the outer lead 21 whose surface is plated with tin 22, thereby attaching the conductive member 2 to the outer lead. 21 (Fig. 3(b)). Note that at this time, the conductive member 2 (end portion 2a) may be transferred to the outer lead 21 using ultrasonic waves or the like. Next, it is immersed in a solder bath to plate the surface of the other end 2b of the conductive member 2 with solder 23 (for example, 60Sn-40Pb, etc.) (FIG. 3(C)). After mounting the IC package on the printed wiring board 24, the end 2b of the conductive member 2 and the printed wiring board 24 are soldered by reflow heating.
The outer lead 21 and the conductor 25 are connected to each other.
The connection is completed (Fig. 3(d)). In addition, methods for this reflow heating include infrared irradiation, hot air injection, and VPS (
Vapor Phase reflow Soldin
g) Methods such as pressure treatment while heating with a heater block, local heating with laser or plasma, etc. can be adopted.

As described above, the connection method of the present invention makes it easy to connect an IC package with a printed wiring board even in an IC package having narrowly pinched outer leads, and enables high-density mounting of an IC chip with a multi-pin configuration with narrow outer lead spacing. Become.

Note that in this embodiment, one conductive member 2 is transferred to one outer lead 21, but the present invention is not limited to this, and a plurality of conductive members 2 may be transferred to one outer lead 21. good.

〔Effect of the invention〕

As detailed above, in the mounting method of the present invention, it is possible to connect the outer leads to the conductors of the printed wiring board even for IC packages in which the distance between adjacent outer leads is 0.4+n or less. It is possible to realize high-density packaging in an IC chip with a multi-bin configuration with narrow outer lead spacing. Further, the I of the present invention has a conductive member whose exposed end is solder-plated and is transferred to the outer lead.
The C package can be used with any printed wiring board.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of an electrical connection member used in the mounting method of the present invention, Fig. 2 is a cross-sectional view showing an example of the manufacturing process of this electrical connection member, and Fig. 3 is a cross-sectional view of the electrical connection member used in the mounting method of the present invention. FIGS. 4 and 5 are schematic cross-sectional views showing the state of implementation of the conventional mounting method, and FIG. 6 is a schematic view showing an example of how the electrical connection member is used.

Claims (2)

[Claims] 1. A method for mounting electrical circuit components that includes a process of connecting an outer lead of an IC package and a conductor of a printed wiring board by soldering, the method comprising: a holder made of an electrically insulating material; , a step of transferring one exposed end of the conductive member of an electrical connection member comprising a plurality of conductive members whose both ends are exposed from both surfaces of the holder to an outer lead of the IC package; , a step of plating the other exposed end of the conductive member with solder; and a step of connecting the conductive member and the conductor of the printed wiring board by soldering. Method. 2. An IC package having an outer lead includes: a holder made of an electrically insulating material; and a plurality of conductive members provided in the holder insulated from each other, both ends of which are exposed from both sides of the holder. An IC characterized in that one exposed end of a conductive member of the electrical connection member is transferred to the outer lead, and the other exposed end of the conductive member is coated with solder. package.