High heat-resistant coating material that prevents delamination

Delamination between molding compounds and substrates is caused by a difference in thermal stress between power semiconductor component materials. The main cause of this thermal stress problem is an increase in the operating temperature of power semiconductors. The high heat-resistant coating material "HIMAL" has a good heat resistance (glass-transition temperature (Tg) of 220ºC and thermal decomposition temperature (Td5) of 410ºC). Even under severe temperature environments the delamination problem is prevented by the high adhesiveness and flexibility of "HIMAL" with its good reliability. The high heat resistance and adhesiveness of "HIMAL" is highly evaluated and the material is used by some of the leading customers for power modules in hybrid and electric vehicles.

Delamination between molding compounds and substrates is caused by the difference in thermal stress among power semiconductor component materials. "HIMAL" <HL-1210G2> with a linear expansion coefficient of about 60 ppm and an elastic modulus of 2.6 GPa is more flexible compared to molding compounds, semiconductor chips and lead frame metals. Therefore the material can reduce the stress caused during temperature increase in manufacturing processing and prevent delamination in semiconductor packages.

Enhances insulation in semiconductor packages and saves space

The sizes of power semiconductor packages handling 1700 V or more of higher voltages have been increasing to ensure insulation performance. "HIMAL" has a high break down voltage of 230 V/µm or more and it achieves partial insulation performance without upsizing packages.

Even under severe temperature environments "HIMAL" can reduce the stress caused between component materials by preventing delamination due to the high heat resistance and adhesive strength. Therefore the temperature of the thermal cycle test (TCT) which is conventionally carried out between -40ºC and 125ºC, can be increased up to 175ºC. Furthermore the power cycle test (PCT) indicating the power cycle lifetime can nearly be doubled^※.

Power Cycle Lifetime Improvement Results

	"HIMAL" Application	Power Cycle Lifetime※	SAT Observation Results
①		12,000 times	Delamination between molding compound and Ni-plated Cu substrate
②		22,000 times	No delamination between molding compound and Ni-plated Cu substrate (adhered condition)

Experiment conditions: Operating temperature: 180℃, Subjects of comparison: (1) Ni-plated Cu substrate + molding compound, (2) Ni-plated Cu substrate + "HIMAL" + molding compound

• ※ Our study Set as 10% increase of the power cycle lifetime Tj,max

10 times or more of insulation performance of molding compounds reduces leak current

"HIMAL" provides about 10 times the insulation performance (> 230 V/µm) compared to general molding compounds. Leak current can be reduced by applying it to areas in packages where leak current is likely to occur.