DELO has developed a pioneering solution: UV-curing molding compounds. These not only minimize warpage and die shift, but also considerablyreduce energy consumption and curing time. Our feasibility study confirms the advantages over conventional heat-curing processes.

UV solution to reduce warpage and die shift

Warpage is caused by chemical shrinkage of the mold compound either during curing or cooling after heat curing. The different coefficients of thermal expansion (CTE) of silicon chips, the molding compound and carrier substrate lead to warpage of the entire assembly.

Die shift results from the molding compound being highly filled and therefore pasty, and can therefore only be processed with heat and high pressure. As the chips are temporarily bonded to the substrates, this bonding can soften due to heat. This causes dies to shift under the pressure required to press the molding material.

DELO's process starts with a temporary adhesive on the carrier wafer and test chips positioned face-down on the wafer. Instead of the usual high-viscosity, heat-curing material, we use a low-viscosity, UV-curing DELO material. Our studies prove this: Cooling after heat curing causes warpage, which is significantly reduced with our method. UV light at room temperature minimizes the effect of the different CTEs of the molding compound and carrier material, thus minimizing the warpage of the wafer.

Advantages:

• No temperature differences during curing and further processing
• Reduced filler content: lower viscosity and modulus of elasticity for easier processing
• Avoids die shift: no heat and pressure requirement thanks to modulus of elasticity of 1 GPa
• Saves time and energy: faster processes, lower energy consumption
• Conserves resources: Less waste caused by warpage or die shift

Development steps and advantages

Our feasibility study shows that temperatures between curing and further processing do not play a role thanks to UV-curing at room temperature. This effectively reduces both warpage and die shift. Our tests with a model adhesive achieved impressive results: Aviscosity of 35,000 mPa-s and a Young’s modulus of 1 GPa. Compared to the usual 800,000 mPa-s and double-digit GPa values of conventional materials, our method almost eliminates die shift.

Conclusion

With UV-curing potting compounds, DELO offers a future-oriented solution for the challenges of fan-out wafer-level packaging. You benefit from reduced warpage, avoided die shift and lower energy consumption. Our innovation paves the way for more efficient and resource-saving production processes in the semiconductor industry.

Interested in more information about our UV-curing potting compounds? Take advantage of our free project consultation!