Screen plate capable of solving BGA four-corner short circuit and manufacturing method

Abstract

Disclosed are a screen plate capable of solving BGA four-corner short circuit and a manufacturing method; and a corner hole and a secondary corner hole of the screen plate are offset to the outside. The manufacturing method comprises the steps of S1, punching four holes from the center of the screen plate; S2, punching holes outwardly based on the four holes obtained in the step 1; S3, punching holes outwardly based on the holes obtained in the step 2; S4, repeatedly punching holes outwardly according to requirements of a circuit board on sizes and numbers of holes, wherein the holes are independent from each other; and S5, punching rectangular coil edge holes in the outermost side, wherein the secondary corner holes and corner holes of the rectangular coil on the outermost layer are punched outwardly in an offset manner. By moving the four edge corners which easily suffer form short circuit of the screen plate to the outside, deformation extrusion interference of the edge corner holes after deformation of the screen plate can be prevented, so that the short circuit problem is solved, and short circuit reject ratio is greatly lowered, thereby saving a huge maintenance cost and improving yield; in addition, it is hard to repair a BGA short circuit, and scrapping is caused by improper maintenance and the rejection rate can reach about 2%; and by virtue of the screen plate provided by the invention, cost can be saved and maintenance manpower cost also can be lowered.

Description

technical field [0001] The invention relates to the technical field of circuit board design, in particular to a method for designing a screen board for solving short-circuit defects at four corners of a BGA. Background technique [0002] At present, in the industry, it is very common to use BGA (Ball Array Package) soldering technology on boards. The requirements for BGA soldering technology are relatively high, including very high requirements for machine placement accuracy. Because BGA belongs to the matrix arrangement of solder balls, the pitch of solder balls is getting denser and smaller, which brings higher difficulty to soldering. On the SMT factory side, BGA soldering failures are still common. With the accumulation of experience, the general failures have been basically controlled. However, for now, there is a kind of BGA defect that is still difficult to achieve better control. That is the BGA chip. During reflow (reflow soldering), a certain deformation will occ...

AI Technical Summary

Problems solved by technology

However, when the design of the opening of the stencil is reduced, and the short circuit still occurs, it becomes helpless

Images