Driving contact hole resolution to 45nm using novel process enhancement techniques

Without question, one of the most difficult layers to print with a usable process window is the contact level. As the industry moves towards the 45nm node and beyond, the challenges associated with printing contact holes with a manufacturable process window have become increasingly difficult. The authors have taken a two-pronged approach that combines chemical and plasma etch methods in order to shrink contact holes and thus obtain higher resolution. Process windows were looked at using both methods individually, and then with both techniques combined. There are several resolution-enhancing chemical shrink materials on the market. In this discussion of contact resolution enhancement, the authors chose JSR CSX004. A relatively new etch approach, focused on reducing contact hole size, will be demonstrated. The etch process utilizes a SiARC ARC, which acts as a hardmask in order to create an enhanced contact hole. In this paper, the authors will describe an approach that will illustrate a methodology that can be used to produce 45nm node contact resolution in a manufacturing environment. Lithographic process windows, side-wall angles (via SEM cross section) and etch selectivity will be studied in detail.