JPS58951B2 - Soldering method and soldering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for efficiently soldering terminals of an integrated circuit having a large number of terminals to lands provided on a printed wiring board.

2. Description of the Related Art Various structures have been proposed for integrated circuits used in electronic devices, depending on the purpose of use.

Figure 1 is a structural explanatory diagram of a flat integrated circuit.

b and C show a front view, a side view, and an enlarged view of the AA cross section in a.

Reference numeral 1 denotes an integrated circuit, from the side of which a large number of horizontally shaped terminals 2 protrude at a pitch of 1.27 mm.

These terminals 2 correspond to 1 on the printed wiring board 3.
．． It is soldered with solder 5 to a large number of lands 4 formed with 27 mm pinches, respectively.

Conventionally, the above-mentioned soldering method is as follows: (a) A soldering iron with a thin tip is used to solder one terminal at a time.

(a) Solder one row of terminals 2 to lands 4 at the same time using a soldering iron with a width corresponding to the width of one row of terminals.

(1) Apply solder to terminal 2 and land 4 in advance, align terminal 2 and land 4 with each other using a jig, pass them through a tunnel furnace, and apply solder that has been applied in advance. Remelt and solder.

There are construction methods such as

Among these methods, method (g) requires a large number of man-hours, and method (b) has lands 4 arranged close together, and the solder adheres to the tip of the solder tip.
The amount of solder attached is generally larger than the amount of solder required to connect terminal 2 and land 4, so the amount of solder attached to land 4 is
A so-called solder bridge is likely to occur between the layers.

In addition, in method (2), the integrated circuit 1 mounted on the printed wiring board 3 is passed through a tunnel furnace and is exposed to high temperatures, so the built-in transistors cannot withstand high temperatures due to electrical performance. There were problems such as.

The present invention was made in order to solve the problems such as the number of man-hours, solder bridging, and heat resistance of transistors as described above, and its purpose is to connect the terminals 2 of the integrated circuit 1 to the printed wiring board 3. The purpose of this invention is to efficiently perform the soldering work to the lands 4 and improve the reliability of the solder connection and the integrated circuit 1, and will be described in detail below with reference to the drawings.

FIG. 2 is a schematic perspective view showing an embodiment of the present invention, in which 6 is a table, 7 is a rotating table placed thereon, and 9 is placed on the table 6.
It is provided with a mechanism for rotation in 0 degree increments and movement in the XY axis directions.

A guide pin 8 is embedded in the rotating table 7 and corresponds to a hole 9 made in the printed wiring board 3, and by fitting these two together, the printed wiring board 3 can be accurately positioned on the rotating table 7. It will be held in

A large number of lands 4 and wiring conductors 10 as shown in FIG. 1C are formed on the surface of the printed wiring board 3, and the lands 4 are arranged under the terminals 2 of the integrated circuit 1, respectively.

A required amount of solder is attached to the terminal 2 and land 4 in advance.

Reference numeral 11 denotes a column provided on the base 6, and 12 denotes an arm attached to the column 11, which moves vertically relative to the column 11 as shown by arrow A.

A heater 14 is attached to the tip 13 of the arm 12.
Reference numeral 5 denotes a thermo-pressure welding block which is partially inserted into the heater 14 and is installed so that heat is supplied thereto.

The thermo-pressure welding block 15 is provided with a liquid supplying vibrator 16, and here the case is shown in which liquid 19 is injected from an injection port 18 at the tip of the tube 17.

FIG. 3 is for explaining the detailed structure of the thermocompression welding block 15, and a is a front view and b is a side view.

The thermocompression welding block 15 is made of two metals 20 and 21 that have good thermal conductivity, for example copper, and the surface is plated with a metal that does not wet with solder (for example, tin and lead), for example chromium. ing.

The metals 20 and 21 are in planar contact, and a vertical groove 22, a horizontal groove 23, and a small vertical groove 24 are formed in at least one surface of the metal 20 and 21 in contact. By bringing the metals 20 and 21 into contact, these grooves 22, 23 and 24 form a flow path 25.

The flow path 25 is open to the surface of the block 15=, and one end of the flow path communicates with the liquid supply pipe 16, and the curved end communicates with the opening 26 at the tip of the block 15.

Next, the operation will be explained.

When soldering, first, the printed wiring board 3 is positioned by fitting the pins 8 installed on the rotary table 7 on the table 6 into the holes 9 provided in the printed wiring board 3.

Next, each terminal 2 of the integrated circuit 1 to be soldered
The positioning is performed so that it is located on the corresponding position of the land 4 provided on the printed wiring board 3.

In this state, when the arm 12 supporting the thermocompression welding block 15 is lowered, the thermocompression welding block 15 moves downward as shown by arrow B, and its tips mechanically come into contact with the terminals 2 that are aligned in a row. do.

Note that the liquid 19 is injected into the thermo-pressure welding block 15 from the liquid inlet 18, but this liquid may be one that evaporates little or does not evaporate at the melting temperature of the solder even if it is heated while passing through the flow path 25; For example, peanut oil is used.

When the tip of the thermocompression welding block 15 comes into contact with the terminal 2, heated liquid flows out around the terminal 2 from the opening 26 at the tip.

This heat melts the solder that has been previously attached to the surfaces of the terminals 2 and lands 4, and the terminals 2 arranged in a row and the above-mentioned lands 4 are soldered at once.

The reason why liquid 19 was used as a heat medium here is as follows.

That is, when a large number of terminals 2 are lined up, it is difficult to make mechanical contact between the tip of the thermocompression welding block 15 and the terminals 2 at once.

Furthermore, even if they make contact at once, it is a point contact, so the thermal conductivity will be extremely low.

A liquid is used to increase this thermal conductivity.

Next, the reason why the surface of the thermocompression welding block 150 is plated with a metal that does not adhere to solder is as follows.

In other words, no solder is attached to the tip of the thermocompression welding block 15, and only the required amount of solder is attached to the terminals 2 and lands 4, so that the solder bridging between the lands 4, which is a drawback of the conventional method, is avoided. It will never occur.

As is clear from the above description, 1. According to the present invention, soldering time is shortened, solder bridging is prevented, and there is no thermal effect on integrated circuits, resulting in reduced production costs and reliability. It has advantages such as improved properties, and has a remarkable effect when put into practical use.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the structure of a flat integrated circuit. b and C are respectively a front view, a side view, and an enlarged cross-sectional view; FIG. 2 is a schematic perspective view showing an embodiment of the present invention; FIG. 3 a
and b are a front view and a side view for explaining the detailed structure of the pressure welding block used in the present invention. 1: Integrated circuit, 2: Terminal, 3: Printed wiring board, 4: Land, 7: Rotating table, 11: Support column, 12: Arm, 14: Heater, 15: Block for thermo-pressure welding, 16: Pipe for liquid supply,
18: Liquid inlet, 22: Vertical groove, 23: Horizontal groove, 24: Small vertical groove, 25: Channel, 26: Opening.

Claims (1)

[Scope of Claims] 1. A liquid flow path penetrating from the upper position to the lower position is formed in the thermo-pressure welding block, and the upper position is provided with a liquid inlet, and the lower end face of the lower part is provided with an opening for causing liquid to seep out. , and the surface of the thermo-pressure welding block is covered with a metal that cannot be wetted by solder.
The body of the soldered object to which the required amount of solder has been applied in advance is pressurized by a thermopressure welding block, and a liquid that evaporates little or does not evaporate at the melting temperature of the solder is mixed in from the injection port, and the inside of the liquid flow path is mixed. The method is characterized in that the heated liquid is made to seep out from the opening, and when pressurized, heat is supplied from the thermo-pressure welding block to the body of the soldered object using the liquid as a heat medium. Soldering is a method. 2. A block for thermo-pressure welding, which has a liquid flow path penetrating from the upper position to the lower position, has a liquid inlet at the upper position, and an opening for seeping out the liquid at the lower end surface of the lower part, and is suitable for thermo-pressure welding. The surface of the block is covered with metal that does not wet the solder.
A liquid that evaporates little or does not evaporate at the melting temperature of the solder flows in from the injection port, heats the liquid in the liquid flow path, and causes the heated liquid to seep out from the opening, causing the solder to adhere when pressurized. A soldering device characterized in that heat is supplied to the body from a thermopressure welding block using a liquid as a heat medium.