Recent press releases, as well as papers presented at the June 2018 IITC conference have increased the buzz about cobalt metallization. As a replacement for tungsten at the local interconnect / Metal 0 level, cobalt has been in development for years, and has been qualified for volume production in logic devices at N10 / N7 nodes. Device manufacturers face ongoing challenges on other metal levels with conventional acidic copper electrochemical deposition, as devices shrink below the 10 nm node. This has led to the development of cobalt also being proposed to replace copper at the Metal 1 level in dual damascene structures at N5, with some integration schemes proposing cobalt through the Metal 4 layer.
Because of cobalt’s acknowledged electrical performance gains, aveni also has a wet solution for cobalt filling. Our electrografted Kari™ deposition process offers a simple, elegant method to realize the performance benefits of cobalt without the multi-step complexities associated with vapor-deposition. aveni’s process is free of the fluorine associated with precursors required for dry deposition, and does not contain sulfur, like competitor wet chemistries. The Kari process ensures void-free cobalt filling with low contamination and large grains for lower resistivity and effective CMP.
Yet, aveni has demonstrated that with the right copper chemistry, such as our alkaline-based Sao™ electroplating chemistry, combined with process know-how, copper has a long life ahead for lower metal levels (M1 – M4). Advanced nodes (N7 / N5) do not necessarily require the complex and costly retooling associated with the introduction of cobalt.