IMEC and its 3D integration partners have taped-out Etna, a new proof-of-concept 3D chip comprising a commercial DRAM stacked on top of a 25µm thick logic die using through-silicon vias (TSVs) and micro-bumps.

This 3D demonstrator mimics all aspects of the technique by stacking an advanced commercial DRAM chip on IMEC’s proprietary CMOS logic IC. As an example, heaters are integrated to test the impact of hotspots on DRAM refresh times. The chip also contains test structures for monitoring thermo-mechanical stress in a 3D stack, ESD (electro-static discharge) hazards, electrical characteristics of TSVs and micro-bumps, fault models for TSVs, etc.

ETNA 3D chip stack paving the way for DRAM on logic integration;
(top) stack configuration; (bottom) layout of the logic die.

 The design of the 3D chip has been realized with many players in the 3D integration supply chain. Now, IMEC is manufacturing the logic die in its prototype line, and will be stacking the commercial DRAM chip on top of it. One of IMEC’s 3D integration partners will deliver the DRAM dies, and will test the fabricated 3D stack; two other partners, will package the 3D stack using flip-chip onto a FBGA (fine-pitch ball-grid array) substrate.

About IMEC
IMEC is a world-leading independent research center in nanoelectronics and nanotechnology. IMEC is headquartered in Leuven, Belgium, and has offices in Belgium, the Netherlands, Taiwan, US, China and Japan. Its staff of more than 1,650 people include over 550 industrial residents and guest researchers. In 2008, IMEC's revenue (P&L) was 270 million euro.

IMEC's More Moore research targets semiconductor scaling for the 22nm technology node and beyond. With its More than Moore research, IMEC invents technology for nomadic embedded systems, wireless autonomous transducer solutions, biomedical electronics, photovoltaics, organic electronics and GaN power electronics.

IMEC's research bridges the gap between the fundamental research at universities and R&D in the industry. It has unique processing and system know-how, intellectual property portfolio, state-of-the-art infrastructure, and a strong and worldwide network position. This makes IMEC a key partner for shaping the technology of the future.

Further information on IMEC can be found at www.imec.be.