Semiconductor equipment manufacturers have announced that material engineering has achieved technological breakthroughs that can accelerate chip performance in the era of big data and artificial intelligence (AI). Applied materials show that the major metal materials transformation of the first transistor contacts and wires in the past 20 years can be lifted. The main performance bottleneck of nano-wafer and below wafer processes, because the electrical performance of tungsten (W) in transistor contacts and the local termination metal wire process of copper (Cu) have approached the physical limit, which is a bottleneck for FinFET to fully perform. Chip designers can replace tungsten and copper with cobalt (Co) metal below 7 nanometers to increase chip performance by 15%.
Cobalt can be used to optimize the process of metal filling in advanced processes, and the process shrinks below 7 nanometers.
Tungsten and copper are important metal materials used in advanced processes. However, tungsten and copper have poor adhesion to the insulating layer. Therefore, a liner layer is required to increase the adhesion between the metal and the insulating layer. In addition, in order to avoid blocking tungsten and The copper atoms diffuse into the insulating layer and affect the chip's electrical properties. A barrier layer must exist.
As shown in the figure below, as the process is reduced to less than 20 nm, Tungsten Contact (the connection between the metal wire and the transistor is called Contact, since the actual shape of the Contact is very close to the cone of the cylinder, the Contact CD generally refers to For example, in the Contact diameter process, the Barrier is 8 nm in the 20 nm Contact CD, the actual metal layer in Contact is 12 nm (Metal Fill 8nm+ Nucleation 4nm), and when the Contact CD is 10 nm, the actual metal layer is only 2 nm. In this way, when the Contact CD is 8 nm, there will be no metal layer storage space, and the thickness of the liner and the barrier layer becomes the process shrinkage bottleneck. 20180702-material-1 Tungsten Contact metal fill case. (Source: Applied Materials ; Finishing: Tuoba Research Institute)
However, if the same 10 nm Contact CD uses cobalt (as shown below), the barrier layer is only 4 nanometers, while the actual metal layer is 6 nanometers, which has more potential to continue to develop under 7 nanometers compared to tungsten. 20180702-material- 2Cobalt Contact metal fill case. (Source: Applied Materials; Finishing: Tuoba Research)
Metal materials revolution will affect the research and development direction of China's semiconductor equipment
At present, China's semiconductor equipment is the fastest in the development of etching, thin film and CMP. This part will be aimed at entering the mainstream manufacturer's production line, obtaining certification and establishing mass production data, aiming at the long-term process of the advanced transistor process. The goal is quite clear. However, compared with the technical level of international mainstream semiconductor equipment manufacturers, Chinese semiconductor equipment manufacturers are still followers. Therefore, the trend of cobalt replacing tungsten and copper is established, which will affect Chinese semiconductor equipment manufacturers, especially etching, thin film and CMP. Research and development direction.