JPH01227491A - Method of packaging electronic components - Google Patents

Abstract

PURPOSE:To enable a semiconductor device with a small lead pitch to be packaged at a low cost and with high soldering quality, by depositing an adhesive material on electrode terminals of an electronic component part so that solder powder is adhered on the terminals by means of the adhesivity of said material, mounting the component on a conductor of a board and heating them so that the electrode terminals are connected with the conductor of the board by means of the molten solder powder. CONSTITUTION:An adhesive material is deposited on an electrode terminal of an electronic component part 2 so that solder powder 5 or fine particles of solder are adhered on the electrode terminal by means of the adhesivity of the material. The electronic component 1 put on a conductor of a board 11 is heated so that the electrode terminal is connected to the conductor of the board 11 by means of the molten solder powder 5 or fine particles of solder. According to an embodiment, a semiconductor 2 is sucked by a suction pin 1 and leads are brought into contact with a sponge impregnated with flux so that the flux is applied on the leads. The leads are then put on the solder powder 5 so that the solder powder 5 is adhered therein. An image recognizer 8 then determines an amount of deviation by which the position of the leads is to be corrected with respect to the suction pin 1. On the other hand, an image recognizer 9 determines an amount of deviation of copper foils on the board 11. These amounts of deviation are fed back to a transporting apparatus 10, which put the semiconductor 2 on the board 11 correctly. The lead section is heated by hot air 13 to melt the solder and connected to the copper foil of the board by the molten solder.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of mounting electronic components constituting an electric circuit.

BACKGROUND OF THE INVENTION In recent years, electronic components have become smaller and more precise with the development of communication equipment, audio equipment, etc., and this trend is expected to continue.

An example of a conventional electronic component mounting method will be described below with reference to the drawings.

FIG. 6 shows a method for mounting electronic components using the conventional screen printing method. In the figure, 21 is a substrate;
22 is a screen version, 23 is cream solder, and 24 is a squeegee.

Next, the implementation method and its operation will be explained below.

A mixture of solder powder and flux in a fluidized state is called cream solder. This cream solder is printed on the conductor of the substrate 21 by screen printing as shown in FIG. 2A. Next, as shown in the opening of the figure, the electrode terminals 25& of the electronic component 26 are placed on the printed cream solder 23a. At this time, the electronic component 26 is temporarily fixed to the substrate 21 by the cream solder 2S and its own viscosity. Thereafter, as shown in FIG.
The electrode terminal 25a and the conductor of the substrate 21 are joined.

Problems to be Solved by the Invention However, the above configuration cannot cope with high-density packaging of semiconductors. There are two main reasons for this.

When supplying cream solder by screen printing, if the lead pitch is less than the O, S pitch, it is extremely difficult to print the cream solder accurately without misalignment along the conductor pattern of the board. Even if the misalignment were eliminated using image recognition processing, the cream solder would stick to the screen plate, making it difficult to maintain print quality such as the amount of solder, resulting in poor yield.

The present invention aims to address the above-mentioned problem and to mount semiconductors with a small lead pitch at a low cost and with high soldering quality.

Means for Solving the Problems In order to solve the above-mentioned problems, the electronic component mounting method of the present invention attaches an adhesive substance to the electrode terminals of the electronic component, and uses this adhesive force to form solder powder or minute solder particles. is attached to the electrode terminal, this component is placed on the conductor of the board and heated, and the electrode terminal and the conductor of the board are connected using molten solder powder or minute solder particles.

Function The present invention provides a method for supplying solder when mounting electronic components on a board, in which cream solder made by mixing solder powder and flux into a fluid state is supplied onto the conductor of the board by means of printing. Instead, an adhesive substance is attached to the electrode terminal of an electronic component, and this adhesive force causes solder powder or minute solder particles to adhere to the electrode terminal, and this component is placed on the conductor of the board and heated to melt it. By connecting the electrode terminal and the conductor of the board with solder powder or minute solder particles, it is possible to reduce the yield due to printing defects such as printing misalignment between the cream solder and the conductor of the board, and uneven amount of solder due to blindness of the screen plate. This makes it possible to mount semiconductors with small lead pitches at low cost and with high quality soldering.

EXAMPLES Below, a method for mounting an electronic component according to an example of the present invention will be explained with reference to the drawings.

FIG. 1 shows the process of an electronic component mounting method in an embodiment of the present invention. A method for mounting electronic components will be specifically described and explained using this figure.

A semiconductor 2 is sucked and taken out from a parts pallet 3 with a suction pin 1. Place the semiconductor 2 in contact with the sponge 4 impregnated with Fuchs, and place the lead of the semiconductor 2 on the sponge 4.
Put on Lux. Next, place the semiconductor 2 on top of the solder powder 6 and apply the solder powder to the leads. Next, this semiconductor 2 is moved onto the image recognition device 8, and the amount of correction of the deviation of the normal position with respect to the suction pin is determined. Similarly, the substrate 1
The amount of correction for the amount of deviation of the copper foil No. 1 is also determined by the image recognition device 9.

These two correction amounts are fed back to the semiconductor 2 moving device 1o to place the semiconductor 2 on the substrate 11. semiconductor 2
Hot air 1 is emitted from the heater 12 while holding down the lead part.
3. Heat to melt the solder and connect.

Note that the supply section 7 for the solder powder 6 is isolated from the air by an anti-oxidation gas 14 in order to prevent the solder powder from oxidizing.
In addition, in order to keep the amount of solder supplied constant, solder powder is supplied at appropriate times, and irregularities are smoothed out with a squeegee 6.

In this embodiment, the sponge 4 is used as a method of supplying flux, but the flux may be made into a spray and sprayed onto the leads. Further, although the hot air 13 emitted by the heater 12 is used as a heating method, in addition to local heating methods such as infrared rays and lasers, a whole heating method such as placing the entire substrate 11 in a heating furnace may be used.

Furthermore, the solder powder supply section 7 may apply vibration to the powder storage box 16 as shown in FIG. 2 as a method of eliminating unevenness on the top surface of the solder powder. Alternatively, as shown in FIG. 3, the squeegee 6 may be fixed and the disc 16 on which the solder powder is placed may be rotated.

Alternatively, as shown in FIG. 4, the particles may be sieved through a sieve 17.

As described above, according to this embodiment, 7lux is attached to the y-de of the semiconductor, solder powder is attached to the leads by the adhesive force of the flux, and this component is placed on the conductor of the board and heated. However, by connecting the leads and the conductor on the board with molten solder powder, the amount of solder may vary due to printing misalignment between the cream solder and the conductor on the board, which is a drawback of the cream solder printing method, and the blindness of the screen plate. This eliminates the decrease in yield caused by such factors.

In addition, with the printing method, when recognizing the copper foil on the board with an image recognition device, cream solder is printed on the copper foil and the copper foil cannot be seen directly, so a separate recognition mark was required, but in this example Since nothing is attached to the copper foil, there is no need to attach a recognition mark, and since the copper foil is directly recognized, it can be mounted with high precision.

Effects of the Invention As described above, the present invention eliminates the disadvantages of solder supply by printing, such as printing misalignment between the cream solder and the conductor on the board, and a decrease in yield due to uneven solder amount due to blindness on the screen plate. It makes it possible to mount semiconductors with small lead pitches at low cost and with high quality soldering.

Moreover, since nothing is attached to the copper foil, there is no need to attach a recognition mark, and since the copper foil is directly recognized, it can be mounted with high precision.

[Brief explanation of the drawing]

Fig. 1 is a process diagram of an electronic component mounting method according to an embodiment of the present invention, Figs. 2 to 4 are process diagrams of main parts, respectively, and Fig. 6 is a process diagram of a conventional electronic component mounting method. It is. 2...Semiconductor, 6...Solder powder, 11
... Board, 12 ... Heater. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4

Claims (1)

[Claims] 1. A substance with adhesive force is attached to the electrode terminal of an electronic component, solder powder or minute solder particles are attached to the electrode terminal by this adhesive force, and this component is placed on the conductor of the board. Heat,
A method for mounting electronic components, characterized by connecting an electrode terminal and a conductor on a board using molten solder powder or minute solder particles. 2. The electronic component mounting method according to claim 1, characterized in that flux is used as the adhesive substance.