Drawing test method and device for evaluating binding strength of PCB bonding pad
A pull-out test and bond strength technology, applied in measuring devices, mechanical devices, instruments, etc., to achieve the effect of strong operability, easy automation, and simple steps
Inactive Publication Date: 2014-12-03
GUILIN UNIV OF ELECTRONIC TECH
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Problems solved by technology
[0003] The purpose of the present invention is to aim at the deficiencies in the prior art, and provide a kind of pull-out test method and device that evaluates PCB bonding strength, this method does not need expensive special supporting equipment to test, and does not need It requires special materials for pulling pins and special test fixtures. This method has simple steps, strong operability, good versatility and practicability, and is easy to automate the testing process. In order to prevent PCB pad crater failure, Enhanced product reliability provides an effective technical means; this device is low in cost, easy to operate, high in practicability and versatility
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[0030] refer to image 3 , a pull-out test device for evaluating the bonding strength of PCB pads, comprising a base 7, and also comprising
[0031] A clamp, the clamp is arranged on the upper part of the base 7, the clamp head 8 of the clamp faces downward, and the clamp head 8 can move up and down;
[0032] heater 9, described heater 9 is arranged on the fixture;
[0033] The sample holder 13 is arranged on the bottom surface of the base 7 and corresponds to the chuck 8 .
[0034] A pull-out test method for evaluating the bonding strength of PCB pads, comprising the above-mentioned test device, and the method comprises the following steps:
[0035] 1) Select test pin 1, and preset solder ball 2 at one end of test pin 1, such as figure 1 shown;
[0036] 2) Select the target PCB sample, and preset the solder joint 6 on the pad 4 of the target PCB sample 3, such as Figures 2a-2c shown;
[0037] 3) Place the target PCB sample 3 in the sample holder 13 of the test device, ...
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The invention discloses a drawing test method for evaluating binding strength of a PCB bonding pad. The method comprises the following steps of firstly preparing a test withdrawing needle with an embedded solder ball and a PCB bonding pad with an embedded solder point, and fixing the withdrawing needle on a drawing device chuck containing a heat source while enabling the withdrawing needle to be perpendicularly aligned to the target bonding pad; then enabling the solder ball of the withdrawing needle to be contacted with the solder point of the bonding pad, starting the heat source, transferring the heat from the heat source to the solder ball through the withdrawing needle, and thus welding the solder ball and the bonding pad by virtue of gravity effect of the molten solder ball; and finally directly starting a drawing device to acquire a cratering failure mode, a maximum release force and a drawing curve of the target bonding pad so as to realize the evaluation for the binding strength of the bonding pad. According to the method, a special drawing device is not needed, and the withdrawing needle which is made of a special material and a special test clamp are not needed, so that the expense is low; the procedure is simple, the operability is high, the universality and practicability are achieved, and the automation of the test process is easy to realize. The invention also discloses a drawing test device for evaluating the binding strength of the PCB bonding pad.
Description
technical field [0001] The invention relates to the technology of printed circuit boards, in particular to a pull-out test method and device for evaluating the bonding strength of PCB pads. Background technique [0002] The use of halogen-free substrates and lead-free solders for printed circuit boards (PCBs) is an inevitable direction for the development of microelectronics manufacturing. In the process of PCB manufacturing and use, multiple reflow soldering and rework processes will cause the interface layer between the PCB pad and the substrate fiber to withstand multiple thermal stresses. In addition, to adapt to lead-free process, the PCB design has also been improved accordingly. These changes not only make the printed circuit board more brittle and more prone to breakage, but also subject the interface layer at the bottom of the PCB pad to higher thermal stress, which can lead to the common phenomenon of PCB pad cracking. As stated in the academic paper [Miao Cai, ...
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IPC IPC(8): G01N19/04
Inventor 蔡苗杨道国邬博义谢冬济万向
Owner GUILIN UNIV OF ELECTRONIC TECH