Application of Thermal Analysis Technology in R&D and Quality Control of Printed Circuit Boards (4)

Figure 6 TGA spectrum of FR4: From the TGA curve, the decomposition of the whole plate is divided into two steps, the total amount of weight loss is 41.9%, which is equivalent to the content of the resin in the FR4 board; the residue is glass fiber, about 57.6% . The DTG curve shows that the FR4 plate decomposes fastest at 300°C. The SDTA curve shows that the maximum exothermic peak appears at 500°C, and there is an endothermic peak at 300°C superimposed on the exothermic peak.

Figure 8 Estimates of the stability of the FR4 plate for different temperatures at the non-model kinetics software.

Bottom left: TGA curves for three different heating rates;
Bottom right graph: Conversion curves for three different heating rates;
Above right: Non-model kinetics conversion rate-activation energy curve;
Top left: Stability prediction under different temperature conditions: If the 5% weight loss is considered to be stable, then at 130°C, 140°C, and 150°C, the FR4 boards can guarantee stable performance in the respective time ranges. It is 11.7 months, 4.4 months, and 1.7 months.

Conjugated MS Analysis of Decomposition Products (TGA-MS)

Coupling FTIR analysis of decomposition products (TGA-FTIR)

Thermal decomposition products can be qualitatively and quantitatively analyzed by coupled mass spectrometers and Fourier infrared spectrometers (Figure 9).

Figure 9 HBr concentration curves recorded by DTG curves and MS spectra of FR4 plates

in conclusion

Thermal analysis technology can provide very comprehensive and useful information for characterization of material properties: For daily quality control and assurance, individual quality and technical specifications can be controlled by selecting individual thermal analysis techniques; while for materials research and development, It is necessary to comprehensively use a variety of thermal analysis techniques to conduct comprehensive research and estimation of the properties of materials.