In 2013, Japan developed a new conductive material
Japan Industrial Technology Research Institute (hereinafter referred to as "Nissan Research Institute") to develop a new material, through a combination of single wall carbon nanotubes (CNT) and copper (Cu), and the realization of the electrical conductivity copper equivalent to about 100 times, and copper carrying capacity (also called the maximum current density). The Institute says, this kind of CNT-Cu composite materials can not only by large current, and light weight, resistance to high temperature, so it can be used as a wiring material ultra compact high performance semiconductor chip using.
So far, the use of global routing and chip semiconductor chip between copper, aluminum wiring material (Al), gold (Au) and other metal. However, the conductivity of these metals although higher, but not necessarily great carrying capacity. High voltage is applied to a certain value above, this voltage will cause the collapse of atomic structure, it will cause resistance increases rapidly, eventually lead wire fracture.
Load flow in the electrical conductivity and high electrical conductivity, high carrying capacity and new materials with the Cu CNT (a). It did not find and have high load and high conductivity material, and CNT-Cu composite also realized two kinds of characteristics (B).
From the use of perspective, with the micro technology, increasing traffic load wiring semiconductor chips requirements. Nissan Research Institute said, to 2015, the carrying capacity will reach Cu and Au can not be achieved in 1000000 (106) A/cm2. While CNT and graphene "carbon nano materials" has reached as high as 1000000000 (109) traffic load of about A/cm2. This is because the coupling capability is very strong with the carbon atoms, even if the voltage is very high, is also very difficult to lead to collapse of atomic structure. However, the conductivity of this material is less than Cu and Au 1/100. Previously, researchers have not found carrying capacity and CNT and Cu and conductivity of the same material.
The diffusion of CNT can inhibit Cu
CNT-Cu composite by CNT and Cu together, for the first time to realize these two kinds of characteristics. The current carrying capacity is 6.3 × 108A/cm2, about 100 times as high as Cu.
Nissan Research Institute said, new materials have been able to obtain the traffic load so high, because the diffusion of CNT can inhibit Cu. In the CNT-Cu composites, CNT and Cu formed a structure like "reinforcing bar concrete", CNT plays a enhanced under high voltage Cu "strength" of the role.
At room temperature, Cu and conductivity of the composites is. But even in the high temperature of 200 ℃, the conductivity of new materials also did not significantly decrease, which is more than Cu and excellent.
Changes of electrical conductivity of CNT-Cu composite and Cu at different temperatures. CNT-Cu composite compared with Cu, conductivity changes in temperature caused by the smaller.
According to Nissan research, production technology and new material is basically the electroplating processing of CNT in the solution containing Cu ions in. The key point is in the organic solution to 1m ~ 5mA/cm2 current density of CNT were slow plating processing, rather than in aqueous solution of copper. So it may be filled in Cu CNT structural body.
Overview of the CNT-Cu composite material manufacturing process. The Nissan research vertically and Nippon Zeon development to the single CNT to level with backward, then copper produced in organic solution and aqueous solution.
At present, there are more than 1000 times the price difference
The biggest problem with this composite material is a single-layer CNT cost is also very high. At present, the monolayer CNT costs 1000 yen to 10000 yen /g (due to the purity vary), and 4300 yen about /g Au almost. Cu costs only about 0.76 yen /g, there is a great gap in price and single CNT.
Nissan Research Institute in the manufacturing of single-layer CNT, adopted the "speeding the growth law of the Institute and Japan ruiweng companies such as the joint development of (Super Growth)", this is a process is capable of producing high purity single CNT. Zeon plans to start by speeding the growth law official mass production of single CNT from 2015. Is likely to cut production costs to 10 yen about /g future.
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