A new wafer scale chip-on-chip (W-COC) packaging technology using adhesive injection method

In order to realize low cost and high density packaging technology, we propose a new wafer scale chip-on-chip (W-COC) packaging technology using the adhesive injection method. In W-COC packaging technology, chip-on-chip modules more than two hundreds are simultaneously formed at the wafer level. In addition, we can significantly improve the chip performance, because small micro-bumps, more than one million, can be formed on a chip and consequently a number of vertical interconnections can be formed between the two bonded chips. Therefore, it is very easy to introduce the parallel processing function in a W-COC module. Using this technology, we propose a new multichip module (MCM) consisting of single or multiple memory chips directly attached to a logic chip. In this paper, we describe key technologies to realize this new multichip module. We fabricated the W-COC test module and investigated its electrical performance using a micro-bump chain.