Method for quickly detecting open-circuit and short-circuit functional defects of PCB micro pad with minimum width of 1 mil

Abstract

The invention discloses a method for quickly detecting the open-circuit and short-circuit functional defects of a PCB micro pad with a minimum width of 1 mil. The method comprises the following steps of: firstly, automatically generating a test file by using engineering software, and manually and locally adjusting the test position of the micro pad in the test file according to the shape of the pad, and generating a test file; selecting a high-precision flying probe tester with a lead screw movement system and selecting the optimal flying probe tester; replacing a micro test tool and performing accuracy correction, replacing a conventional cutter-type test probe on the flying probe tester with a micro probe which is a needle-type test probe dedicated to the micro pad; performing micro-pad alignment design, using the micro pad as an alignment point and performing alignment by using a micro pad center direct alignment method; and setting tester operating parameters. The method for quickly detecting the open-circuit and short-circuit functional defects of a PCB micro pad with a minimum width of 1 mil has good operability, low production difficulty, high efficiency and guaranteed quality.

Description

technical field [0001] The invention relates to the open circuit and short circuit functional detection field of chip-level miniature pads with a pad width of printed circuit boards: 1mil<PAD Size<4mil, specifically a miniature pad with a pad width of 1-4mil for open and short circuits A fast detection method for defects. Background technique [0002] Using the physical contact between the test probe and the conductive pad of the printed circuit board to detect the continuity (Continuity) and insulation performance (Isolation) of the substrate circuit is a conventional solution for inspecting the electrical performance characteristics of the PCB substrate. [0003] The PCB substrate serves as a bridge for signal transmission. With the advent of the 5G era, smart equipment integrated chips led by mobile phone communications have entered the era of 10nm-level chip packaging technology from surface mount. The size of the pads in the BGA / IC area is also getting smaller an...

AI Technical Summary

Problems solved by technology

[0004] When the PAD Size is ≥ 6mil, general-purpose or compound fixture testing is used; when the PAD Size is ≥ 4mil, flying probe testing is used for small batch orders, and only one kind of special conductive material PCR (Pressure sensitiveConductive Rubber) and PTB is used for large batch orders. (PitchTranslation Board) conductive rubber jig test, some manufacturers also use CCD automatic alignment micro-needle jig production, but the test costs of the latter two production modes are quite expensive, small and medium-sized PCB factories, especially those with a variety of small quantities Model enterprises cannot afford it; when PAD Size<4mil and ≥1mil, it has exceeded the limit capability of the above test equipment

For such orders, PCB factories usually use the method of AOI scanning line + manual visual inspection of the outer layer to ship, not only the detection speed is slow and the efficiency is low, it is not suitable for mass production, because the human eye cannot find potential functional defects in the inner layer or between the holes , so there is a serious open and short circuit leakage and face the risk of huge claims

Due to the comprehensive influence of various factors such as the expansion and contraction of the board, film, etc. during the production process of the PCB board, the test equipment itself has a 1-2mil accuracy deviation, resulting in a normal offset of 1-2mil in the test position of the pad center , so that the flying probe machine is inefficient or unable to test the micro-bit pads less than 4mil