The Study of Highest Thickness Photo Resist for Cu Post of Fan-Out Wafer Level Packaging

The mobile device’s limited thermal budget hardly allows the use of a high-performance application (AP) at its full speed. However, as artificial intelligence technologies has been rapidly applied for devices, demand like high-speed and large-capacity signal processing is continuously increasing. Therefore, controlling heat generation AP chip becoming key factor, it necessary to develop Re-Distribution Layer (RDL) based Fan-Out Package (FOPKG) structure that does not increase thickness package while maximizing die dissipation. height Cu post getting higher production FOPKG can apply thick die, in this study, world’s thickest photoresist material (>350um thickness) was developed (>300um thickness). effect light transmittance solubility depending on molecular main polymer were studied lithography process photoresist. Based understanding behavior, optimal liquid type composition developed. Through evaluation characteristics, deep-hole via implementation electro-plating performed obtain yield Cpk 1.27 product design wafer. Depending in-depth experimentation photoresist, possible build an advanced research foundation increasing finer pitch secure dissipation characteristics improve degree freedom architecture.