1. The purpose of the experiment
The lead-free reflow of PCB circuit boards can cause delamination, leading to the breaking of the copper hole walls in plated through holes. This issue primarily arises because the coefficient of thermal expansion (CTE) of the board material along the Z-axis, whether it’s α1 (55-60 ppm/°C) or α2 (250 ppm/°C), significantly exceeds that of copper at 17 ppm/°C. Specifically, the Z-axis thermal expansion rate of the board material below Tg is approximately three times that of the copper walls, and above Tg, it can be as much as 12-20 times greater. To mitigate the risk of multilayer board through holes failing during multiple reflows, we deliberately employ a temperature cycle test (TCT) to investigate three key aspects:
(1) What is the effect of the reflow peak temperature on the board and through holes?
(2) How many reflow cycles can the board withstand?
(3) What is the reliability of the base material?
2. PCB circuit board production
The lead-free reflow of PCB circuit boards can cause delamination, leading to the breaking of the copper hole walls in plated through holes. This issue primarily arises because the coefficient of thermal expansion (CTE) of the board material along the Z-axis, whether it’s α1 (55-60 ppm/°C) or α2 (250 ppm/°C), significantly exceeds that of copper at 17 ppm/°C. Specifically, the Z-axis thermal expansion rate of the board material below Tg is approximately three times that of the copper walls, and above Tg, it can be as much as 12-20 times greater. To mitigate the risk of multilayer board through holes failing during multiple reflows, we deliberately employ a temperature cycle test (TCT) to investigate three key aspects:
(1) What is the effect of the reflow peak temperature on the board and through holes?
(2) How many reflow cycles can the board withstand?
(3) What is the reliability of the base material?
2. PCB circuit board production
