“Disilane” (SiH6) is attracting global attention, in particular in such countries as Korea, Japan, Taiwan, and the US as a cooling material for the latest 20nm semiconductor processes.

For the latest semiconductor integrated circuitry, there has been a need development of more complicated next generation 3 dimensional integrated technology than the fin-based, multigate transistor architecture (Fin FET). At the same time, multi-stratification based on miniaturization is also required. The development of very thin films regarding such items as channels, gates, and wiring has also been accelerating.

In conjunction with this, regarding the fabrication process, for formation of transistor elements there is the front end of the line (FEOL) type for which a temperature of under 500℃ is required. For formation of the wiring elements there is the back end of the line (BEOL) process requiring a temperature of under 350℃. For cryogenic temperatures, there are processes such as the CVD as well as the dubbing and etching processes. The selection of the specialty gas used in the film forming process is very important.

However, when new specialty or new specialty chemical products are used for the cryogenic process, a great deal of concern arises in terms of the ability to rely on product quality and stable supply. Of course, high costs are unavoidable. At this point, what has now become a current major trend is to select from those specialty gas already relied upon, and already used in the semiconductor fabrication process. Quality, stable supply, and price are also to be taken into consideration.

In this sense what is now attracting attention is disilane (micro-circuitry oxide film), dichlorosilane (3DNMAND) and diborane (doping). All of these are specialty gases which have been used in the semiconductor market for the last 30 years.

Even among these, disilane reacts more quickly than silane and it can be activated thermally. It has also been considered to excel in cryogenic processes. Nevertheless, its price tag is higher than that of than other silane type gases such as silane and TEOS. It has therefore only been used in tests. The annual demand in Japan amounts to around 500kg and this has been going on for quite a while.

However, since around 2010 when it is supposed to have been introduced for the cryogenic fabrication process for semiconductors, the demand has skyrocketed because producers overseas such as those in Korea, Taiwan, and the US, as well as those in Japan have adopted the use of disilane. It is estimated that the global demand has expanded to 3 – 4 tons a year.

The major producers of disilane are Mitsui Chemicals in Japan and Voltaix Electronics Chemicals in the US. Voltaix is a US supplier of specialty gases and in addition to disilane, also produces germane. In January of last year it signed a contract with the Linde group company Linde Electronics, and furthermore, in June of the same year it was acquired by Air Liquide.