Gravity magnetic induction chip side-mounting structure and method for improving side-mounting yield

Abstract

The invention relates to the technical field of substrate side-mounting methods, and discloses a gravity magnetic induction chip side-mounting structure and a method for improving the side-mounting yield of the gravity magnetic induction chip side-mounting structure. The method includes: S1, brushing tin paste onto a bonding pad of a substrate; S2, performing primary reflux; S3, flattening the solder balls; S4, performing skip printing of the scaling powder; S5, carrying out the chip surface mounting of the zoning glue; S6, installing the chips by side; and S7, performing secondary backflow tocomplete the side mounting, thus producing the gravity magnetic induction chip side mounting structure. During use, a tin layer with a certain thickness is firstly generated on the substrate bondingpad to ensure effective contact between the chip bump and the substrate bonding pad, and then soldering flux skip printing, glue scratching, chip mounting and reflow soldering are carried out, so thatthe yield of products can be greatly improved; besides, the technical difficulty is reduced, frequent debugging and visual inspection of the tin amount are not needed, the production efficiency is improved, the tin layer with uniform thickness is generated on the substrate bonding pad in advance, and effective contact between the chip Bump and the tin layer on the substrate bonding pad is ensured.

Description

technical field [0001] The invention relates to the technical field of substrate side-mounting methods, in particular to a side-mounting structure of a gravity magnetic induction chip and a method for improving the yield rate of the side-mounting. Background technique [0002] Flipchip die bump is interconnected by stencil-printed solder paste and bond pad by reflow soldering. The design size of the substrate pad made by this process is 150um*90um, and the gap between the pads is 80um. Generally, SMTPad The spacing is 140um. This product has exceeded the minimum size of the SMT Pad design. The design of the stencil opening window is difficult to grasp the scale: too little tin on the stencil will easily lead to false soldering, too much tin will easily lead to bridging, and the expansion and contraction of the substrate and the stencil are inconsistent. , The tin offset leads to false soldering. Therefore, in the actual production process, the amount of tin is determined by...

AI Technical Summary

Problems solved by technology

[0002] Flipchip die bump is interconnected by stencil-printed solder paste and bond pad by reflow soldering. The design size of the substrate pad made by this process is 150um*90um, and the gap between the pads is 80um. Generally, SMTPad The spacing is 140um. This product has exceeded the minimum size of the SMT Pad design. The design of the stencil opening window is difficult to grasp the scale: too little tin on the stencil will easily lead to false soldering, too much tin will easily lead to bridging, and the expansion and contraction of the substrate and the stencil are inconsistent. , tin offset leads to false soldering

Therefore, in the actual production process, the amount of tin is determined by various factors such as stencil window design, printing parameters, stencil expansion and contraction, and substrate processing accuracy. The processing is unstable, the production efficiency of the machine is low, and the product yield is low. Suitable for large-scale mass production, there are mainly three soldering instability phenomena: bridging, insufficient tin amount, and printing offset.

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