Overcoming silicon limitations: new 3D-AFM carbon tips with constantly high-resolution for sub-28nm node semiconductor requirements

The demands on atomic force microscopy (AFM) as a reference technique for precisely determining surface properties and structural designs of multiple patterns in the semiconductor industry are steadily increasing. With the aim to meet ITRS requirements and simultaneously improve the accuracy of AFM-based critical dimension (CD) measurements at constant resolution, the AFM tip more and more becomes a factor crucially determining the AFM performance. In this context, AFM tip limitations are given by lack of sharpness with too large tip radii/diameter, insufficient wear resistance, and high total cost, which does not conform to production environment needs. One technical approach to overcome these tip limitations is provided by electron beam induced processing (EBIP), which allows for manufacturing AFM tips of desired sharpness, shape, and mechanical stability. Here, we present T-shape-like 3D-AFM tips made of bulk amorphous, high density diamond-like carbon (HDC/DLC), and compare their performance and wear resistance to standard silicon tips. We show the advantages of this approach for the semiconductor industry, in particular on AFM3D technology in order to answer to sub-28 nm nodes requirements, and present tips with 15 nm diameter at 10 nm vertical edge height.