SONY established a batch process system that attaches a sensor, a DRAM chip, and a logic chip in a unit of a wafer. On the other hand, it is understood that Samsung Electronics is using a method that makes 2-layered structure with a sensor and a logic chip and attaches DRAM through TC (Thermal Compression) bonding method after flipping over a wafer. From productivity and production cost, SONY has an upper hand. It seems that a reason why Samsung Electronics decided to use its way is because it wanted to avoid using other patents."