JPH0373393A - Solder paste printing mask - Google Patents

Abstract

PURPOSE:To remove clogging of solder paste at a printing pattern opening part which has been miniaturized by a method wherein one printing pattern opening part is bored over a plurality of substrate lands corresponding to a plurality of electrode parts which one electron part has. CONSTITUTION:In a solder paste printing mask 11, one printing pattern opening part 15a is widely bored over substrate lands 14 at two positions corresponding to electrode parts 17 at two positions which one electron part 16 has. The solder paste printing mask 11 is put on the substrate lands, and solder paste 19 is applied by printing between on the substrate lands 14 at two positions through the large printing pattern opening part 15a by sliding a squeegee 18. An electron part 16 is mounted on the substrate lands 14 at those two positions, and reflow soldering is performed. Fused solder generated from the solder paste 19 existing between the substrate lands 14 is also solidified as a soldered joint.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a printed mask for solder paste used when electronic components are mounted on a board and reflow soldered.

(Prior Art) As shown in FIG. 2(B), a conventional solder paste printing mask (also referred to as a stencil) 11 has a thin plate 12
A printed pattern opening 15 having substantially the same shape as the land 14 of the substrate 13 is bored in the substrate 13 . That is, the solder paste printing mask 11 includes electronic components (chip components) 16.
Has two or more electrode parts! Print pattern openings 15 having the same number and substantially the same shape as the substrate lands 14 corresponding to 7 are bored.

Then, as shown in FIG. 2 (Al to (C)), a solder paste printing mask 11 is placed on the substrate 13, and the squeegee 18 is slid on this mask 11 to supply the solder paste onto the mask 11. The solder paste I9 is applied by printing onto the plurality of substrate lands 14 independently through the printed pattern openings 15, and then, as shown in FIG. An electronic component (chip component) 16 is mounted across the board, and finally, reflow soldering is performed as shown in FIG. 2(E).

(Problems to be Solved by the Invention) Currently, as electronic components 16 have become smaller, substrate lands 14 have also become smaller, and accordingly, printed pattern openings 15 have also become smaller. As a result, in the printed pattern openings 15 of conventional masks, When printing solder paste, paste 1
9 tends to get clogged in the print pattern opening 15, making it difficult to print properly.

The present invention aims to improve the problem of solder paste clogging in printed pattern openings, which have become smaller in size.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a method for applying solder paste onto a substrate land 14 through a printed pattern opening 15 formed in a thin plate 12.
In the solder paste printing mask 11 for printing and coating 9, one printed pattern opening 15g is bored across the plurality of substrate lands 14 corresponding to the plurality of electrode parts 17 of the electronic components 16. be.

(Function) According to the present invention, the solder paste 19 is printed not only on the plurality of lands 14 of the substrate 13 but also between the lands 14 through the relatively large print pattern openings +51, but the solder paste 19 is printed not only on the plurality of lands 14 of the substrate 13 but also between the lands 14. is board land 14
Due to the wettability of the component electrode portions 17, the molten solder between the substrate lands 14 is also attracted to any of the substrate lands 14 and the component electrode portion 17 due to the surface tension of the molten solder. land 1
There is no time left between 4.

(Example) Eleven of the present invention will be explained in detail below with reference to an example shown in FIG.

Solder paste printing mask used in this example (
In the stencil 11, one large printed pattern opening 15a is formed in a thin plate 12 over two substrate lands 14 corresponding to two electrode parts 17 of one electronic component (chip component) 16. has been done. For example, in the case of the chip component 1608 (1,6 nunXo, 8 round), even if the planar dimensions of the board land 14 are about 0.8 mm x 0.5 round, the opening size of the printed pattern opening 15a is 0.8 mm x 0.5 round. I1mo+X2. It will be about 0mm.

Then, as shown in Fig. 1 (A) to (C),
A solder paste printing mask 11 is placed on the substrate land 14, and the squeegee 18 is slid on this mask 11 to spread the solder paste 19 supplied onto the mask 11 into the large printed pattern opening 15! Through the printing, printing is applied not only on the two substrate lands 14 but also between the two substrate lands 14.

Next, as shown in FIG. 1(D), an electronic component (chip component) 16 is placed across these two board lands 14.
, and finally, when reflow soldering is performed, the molten solder liquefied by the reflow is attracted to the board land 14 and the electrode part I7 of the electronic component 16 due to its wettability, and the surface of the molten solder Due to the tension, the molten solder generated from the solder paste 19 between the board lands 14 is also drawn to one of the board lands 14 and the component electrode section 17, and as shown in FIG. 1(E), each board land The solder joint 20 is solidified onto the solder joint 14 to which the component electrode portion 17 is soldered.

〔Effect of the invention〕

According to the present invention, since one printed pattern opening is bored across a plurality of substrate lands corresponding to a plurality of electrode parts of one electronic component, the opening area of the printed pattern opening can be greatly increased compared to the conventional one. This can reduce the risk of solder paste clogging the printed pattern openings. Moreover, even when solder paste is printed on multiple circuit board lands using one printed pattern opening, the gap between the bottom surface of the electronic component and the surface of the circuit board is sufficiently narrow, so that spherical melting occurs in this gap. It is impossible for solder to be present, and the molten solder always wets and collects on the board lands and component electrodes, and there is no possibility of causing any bridging between the board lands, allowing normal soldering.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a board showing flow soldering from the solder paste printing process using the solder paste printing mask of the present invention, and Figure 2 is a diagram showing the solder paste printing process using the conventional solder paste printing mask. Flow soldering is a cross-sectional view of the board showing the state. 11... Printing mask, 12... Thin plate, 14... Board land, 15a - Print turn opening, 16... Electronic component, 17... Electrode part, 19... Solder paste. July 13, 1989 Inventor Yoshinobu Abe

Claims (1)

[Claims] (1) In a solder paste printing mask that prints and applies solder paste onto a board land through a printed pattern opening made in a thin plate, a plurality of board lands corresponding to a plurality of electrode parts of one electronic component are used. A solder paste printing mask characterized in that one printing pattern opening is bored throughout the mask.