JPH057476U - Metal mask for cream solder printing - Google Patents

Abstract

(57) [Summary] [Structure] The opening shape of the metal mask for printing the cream solder on the pad on the printed board is made convex so that the width of a part is narrower than the width of the chip component electrode mounted on the printed board. [Effect] Cream solder, which is crushed by pressure when mounting chip parts, does not squeeze out from the pads on the printed circuit board, preventing the occurrence of ball-shaped solder around the chip parts and preventing electrical failure and ball-shape. The work man-hours for removing the solder can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  This invention prints cream solder on the printed circuit board and then prints it on the printed circuit board. A so-called surface soldering process in which electronic components are mounted and then soldered by heating. Metal mask used for printing cream solder in packaging technology .

[0002]

[Prior art]

  Conventionally, the aperture shape of this type of cream solder printing metal mask has been The hole shape was almost the same as the chip component mounting pad on the plate. Therefore, this subordinate Chip parts are printed on a printed board printed with cream solder using a conventional metal mask. When mounted, some of the printed cream solder will eat up from the pads on the printed circuit board. Ball-shaped solder that spills out around the chip components mounted during solder reflow Was attached as.

[0003]

[Problems to be solved by the device]

  In the above-mentioned conventional hole shape of the cream solder printing metal mask, the printing substrate is The width of the pad is wider than the electrode width of the chip component mounted on the board So, print the cream solder on the pad on the printed circuit board and mount the chip parts. Pad for chip component mounting due to pressure during soldering and sagging of cream solder The cream solder oozes out, and the chip part mounted during solder reflow The protruding cream solder forms ball-shaped solder around the body of the product and adheres to it. Cause electrical failure. In addition, a bow attached to prevent the electrical failure. There is a drawback that the number of man-hours required to remove the solder paste is generated.

[0004]

[Means for Solving the Problems]

  The hole shape of the metal mask for cream solder printing of the present invention is The width of a part of the opening for printing the cream solder on the pad fits on the pad. It is characterized in that it is narrower than the width of the electrode of the mounted chip component.

[0005]

【Example】

  Next, the present invention will be described with reference to the drawings.

[0006]   FIG. 1 is an exploded perspective view of an embodiment of the present invention.

[0007]   The printed circuit board 1 has pads 2 provided with printed wiring. This pad 2 and metal mask 3 having openings 4 for printing cream solder 6 The cream solder 6 on the metal mask 3 using the Print on 2.

[0008]   FIG. 2 shows a partial expansion of the cream solder 6 printed on the pad 2 of the printed circuit board 1. It is a big picture. The opening 4 is a quadrangle having the same shape as the pad 2 except for two adjacent corners. The two corners have small square cutouts that are not convex as a whole. You The width 6b between the cutout portions of the opening 4 is the width of the pad 2, that is, the pad. The width is narrower than the width 7a of the chip component 7 mounted on the board 2.

[0009]   The cream solder 6a printed on the pad 2 of the printed board 1 is mounted on the board. The chip component 7 is mounted with a width 6b with which the electrode is in contact with the electrode width 7a of the plug-in component 7 When the pressure is applied, the width 6b where the electrode of the cream solder 6a on the pad 2 contacts is pressed. Since it does not protrude from the pad 2 even if it is bumped, it is around the chip component 7 during solder reflow Prevents generation of ball-shaped solder.

[0010]

[Effect of device]

  As described above, the present invention applies cream solder to the pads on the printed circuit board. The cream solder printed with the opening shape of the metal mask to be printed on the printed circuit board The width of the part that contacts the electrode of the mounted chip component is narrower than the electrode width of the chip component. By making it a convex shape, it is pressed by the pressure when mounting the chip component. The shape of the crushed cream solder does not stick out from the pads on the printed circuit board. Therefore, ball-shaped solder is prevented from being generated around the chip components and electrical failure is prevented. This has the effect of reducing the number of man-hours required to remove the solder paste.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view showing the relationship between the cream solder printed on the pad 2 of the embodiment shown in FIG. 1 and the chip component 7 to be mounted.

[Explanation of symbols]

1,1a Printed circuit board 2,2a pad 3 metal mask 4 Openings 5 squeegee 6,6a Cream solder 6b Width of electrode contact 7 Chip parts 7a electrode width

Claims (2)

[Scope of utility model registration request] 1. A cream solder printing method, wherein a width of a part of an opening for printing cream solder on a pad on a printed board is narrower than a width of an electrode of a chip part mounted on the pad. Metal mask. 2. A convex shape in which a width of a part of an opening for printing cream solder on a rectangular pad on a printed circuit board is narrower than a width of an electrode of a chip component mounted on the pad. A metal mask for cream solder printing, which is characterized by being present.