Products with DRAM at home and in the office
Dynamic random access memory (DRAM), a type of semiconductor memory, is characterized by the ease with which it can be adapted for high speeds and large capacities. It is often embedded in information communications and electronics devices as main memory. For Elpida Memory, Japan's only DRAM manufacturer, increasing the environmental performance of its products constitutes an environmental activity that impacts the whole of society, yielding signifi cant results.
- Typical products with DRAM that are used at home
- Typical products with DRAM that are used in the office
Topics Introduction to eco-products
Creating eco-products by developing TSV technology
Elpida Memory is developing technology for through-silicon vias, or TSVs. By forming small holes in chips and filling them with metal, this technology allows us to create signal wiring in the vertical dimension on layered chips. The conventional approach connects electrodes on layered chips with wire bonding, but TSV technology can be used to dramatically shorten the wiring distance by connecting electrodes on the chip's top and bottom surfaces. This technology, which makes it possible to laminate chips into many layers in a manner resembling mille-feuille, expands design potential to include combination with CPUs, fl ash memory, and other device chips. It is likely to become a key technology for eco-products, which must offer high capacity along with low power consumption.
In a single high-capacity DRAM package, the memory capacity is determined by the number of chips that can be layered together. TSV technology allows the same capacity to be achieved in less mounting area, reducing the amount of materials used, simplifying the design, and boosting the degree of freedom of interface design. In products such as notebook computers and tablet computers, where super-thin device profi les are desirable, this technology will help maintain and improve advanced functionality.
Elpida's TSV technology development project was launched in 2004 with a NEDO grant, and subsequent design and development work was conducted in partnership by the Development Center, Hiroshima Development Center, and Akita Elpida Memory. In 2009, we achieved a 9-layer architecture including the interface chip to produce an 8 Gb DRAM. Augmenting the packaging process at Akita Elpida Memory, the Hiroshima Plant built a TSV production line, and we developed an integrated production system in Japan. In 2011, we began shipping samples. At the beginning of the technical development project, many observers took a skeptical or negative view of the possibility of forming wiring on chips without using wires, which was an unconventional approach. Nonetheless, driven by faith in our ability to create world-leading innovations, we successfully developed samples eight years after the conception of the idea in 2003.
These sample chips reduce operating power consumption by about 20% and standby power consumption by about 50% compared to conventional systems*.
Going forward, we will continue to provide environmentally friendly products in the form of DRAM by pursuing this TSV technology.
* Comparison of a notebook computer equipped with 8Gb TSV DRAM and a system using SO-DIMM memory.
NEDO: New Energy and Industrial Technology Development Organization