JPH0337757B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention particularly relates to a preliminary soldering process for assembling the remaining components by soldering onto a board on which some components have already been assembled and are uneven. This is a technology used for printing solder paste.

B. Prior Art For example, in the manufacturing process of a hybrid IC, as shown in FIG. 1, a semiconductor pellet 1 is electrically connected by wire bonding, and a chip component 2 is electrically connected by soldering. Components with different connection methods are often assembled together on the same board 3. In such cases, one part must be assembled first,
No matter which part is assembled first, the parts that have already been assembled will get in the way, causing problems in the manufacturing process.

In other words, even when attempting to solder and connect other chip components etc. to a board on which some components have already been assembled, the wiring lands 4, 4 on the board 3 to which the chip components 2 etc. are to be assembled. It is necessary to apply solder paste as preliminary solder to ....

In other words, conventional general solder paste application work uses a stainless steel mask with a printed pattern window hole, which is brought into close contact with the board, and solder paste is applied over it with a squeegee to form the window. Solder paste was applied only to the hole positions.

By the way, to explain the structure with some parts already assembled using FIG. 2, 1 is a ceramic substrate 3.
Semiconductor pellets soldered onto the top, 5,5
A bonding wire connects the surface electrode of the semiconductor pellet 1 and wiring lands 4', 4' on the substrate 3, and a precoating agent 6, such as a silicone resin, covers the entire semiconductor pellet 1. The height H of the precoat agent 6 is usually about 2 to 3 mm. Therefore, in this state, the conventional solder paste printing method using the mask described above cannot be carried out, and the work of applying preliminary solder becomes difficult.

C. Structure of the Invention The present invention provides a means for transporting a board with some parts assembled thereon and an uneven surface at a constant speed, and communicating with the bottom of a solder paste container disposed at a position separated by a predetermined length above the position where the board passes. Select an arbitrary number of small-diameter needles arranged in a manner that intersects with the board feeding direction and have needles that move pistons in the holes, and synchronize with the board feeding according to a predetermined printing pattern. According to the printed pattern, the solder paste is dropped and deposited on the desired position on the board by piston movement of only the desired needle at a predetermined timing in synchronization with the feeding of the board. It is designed to print solder paste.

D. Embodiment In FIG. 3 showing an embodiment of the present invention, 7 is a feeding mechanism that positions the substrate 3 and feeds it horizontally at a constant speed, and 8 is a feeding mechanism that is positioned above the substrate passing position and intersects with the substrate feeding direction. This is a solder paste dispenser placed in the This dispenser 8 is the fourth
As shown in the figure, a large number of small-diameter nozzles 10, 10...
are arranged at equal intervals, and needles 11, 11... are provided in the holes to make piston movements.
1. The rear end of the drive mechanism 12 as shown in FIG.
is connected to.

This drive mechanism 12 is rotatably connected to a fixed shaft 1 at one end.
a diaphragm 14 which is pivotally supported by the diaphragm 3 and has the rear end of the needle 11 fixed to the other end; and an electromagnet 15 which attracts the diaphragm 14.
and a compression coil spring 16 that urges the diaphragm 14 away from the electromagnet 15. This drive mechanism 12 causes the needle 11 to perform a piston movement of a predetermined stroke each time its electromagnet 15 is excited. Note that this illustrated example shown in FIG.
This drive mechanism 12 is provided in the same number as the needles 11, 11, . . . .

As shown in FIG. 6, each nozzle 10, 10, . Each tip 10' is arranged at a position above the highest position of the substrate 3 being sent. In the nozzle 10 shown in FIG. 6, when the end 11' of the needle 11 reciprocates once between the root 10b and the tip 10a, the solder paste 17 is filled into the solder paste container 9 and supplied into the nozzle 10. is discharged/dropped in an amount corresponding to the product of the inner diameter of the nozzle 10 and the stroke length of the needle 11.

Therefore, only the desired needles 11, 11, . For example, solder paste can be dropped onto a desired position on the substrate 3. Note that the amount of solder paste 17 to be deposited can be adjusted as appropriate by changing the number of reciprocating movements of needle 11 relative to the feed speed of substrate 3.

E. Effects of the Invention According to the present invention, solder paste can be printed in an arbitrary pattern from a position distant from the substrate on which the solder paste is to be printed. Therefore, even if the board is uneven because some parts have already been assembled, preliminary solder using solder paste can be easily formed at the land positions where the remaining parts are to be soldered and fixed. This facilitates the manufacture of devices, especially hybrid ICs, in which parts that are connected to the board in different ways are assembled together.

According to the present invention, the amount of solder paste deposited on a predetermined location on the board is determined based on the amount corresponding to the product of the inner diameter of the nozzle and the stroke length of the needle, and the amount of solder paste applied to a predetermined location on the board is determined based on the amount of solder paste corresponding to the product of the inner diameter of the nozzle and the stroke length of the needle. It can be adjusted appropriately by the number of piston movements. In addition, since the solder paste is discharged by the piston movement of the needle, the nozzle does not become clogged, and there is no need to attach or detach the nozzle to clean it, which improves workability.

[Brief explanation of the drawing]

Figure 1 is a plan view showing an example of a hybrid IC.
2 is an enlarged sectional view taken along line A-A in FIG. 1, FIG. 3 is a schematic perspective view of an apparatus for implementing the method of the present invention, FIG. 4 is an enlarged perspective view of the dispenser, and
FIG. 6 is an enlarged perspective view of the drive mechanism, FIG. 6 is an enlarged sectional view of the nozzle portion, and FIG. 7 is a plan view showing an example of printing solder paste by the method of the present invention. 1... Semiconductor pellet, 2... Chip parts, 3
... Board, 4 ... Solder paste adhesion position (land for wiring), 6 ... Precoat agent (protrusion on board), 7 ... Feeding mechanism, 8 ... Dispenser, 9
...Solder paste container, 10...Nozzle, 11...
...Needle, 17...Solder paste.

Claims (1)

[Claims] 1 A substrate with unevenness is fed at a constant speed, and a large number of solder paste containers arranged intersecting the feeding direction of the substrate are connected to the bottom of a solder paste container placed at a predetermined distance above the substrate passing position, and are arranged in a hole. Select an arbitrary number of small diameter noises having needles that move pistons in accordance with a predetermined print pattern, synchronize with the feed of the board, follow the print pattern, and print a predetermined number of A method for printing solder paste, characterized in that solder paste is dropped and deposited on a desired position on a substrate by piston movement of only desired needles at a desired timing.