Diamond-like carbon (DLC) molds for nanoimprint lithography (NIL)
Original Publication Date: 2002-Nov-20
Included in the Prior Art Database: 2003-Jun-21
Nanoimprint lithography (NIL) is gaining popularity as a low-cost method for single-level, large-area texturing, and it may have applications in the semiconductor industry if the feature dimensions required for scaling shrink beyond the capabilities of conventional photon-based lithography tools [*]. Nanoimprint lithography utilizes a molding surface having high areas and low areas to imprint a pattern in a deformable resist material. The resist material is then developed so that openings are left in the resist in regions corresponding to the high areas of the mold [*]. A problem with nanoimprint lithography is the finite lifetime of the molding surface, often less than 1000 printings, with cleaning required after every 10 printings. The material comprising the molding surface must be harder than the resist at the temperature at which the imprinting takes place, thermally stable to at least this temperature, non-sticky (to facilitate mold extraction), and easily cleanable. Typically the patterned molding layers for nanoimprint lithography are formed from SiO 2 , and many other materials may be used as well. Disclosed here is a mold for NIL comprising one or more layers of amorphous carbon, such as diamond-like-carbon (DLC, also known as a-C:H) deposited by plasma-assisted chemical vapor deposition or sputtering, or tetrahedral carbon (taC) deposited by pulsed laser, vacuum arc, filtered vacumm arc. Tese are hard, wear-resistant materials that are easily patterned by reactive ion etching in O 2 and/or halogen plasmas (or by any number of probe microscopies in an oxygen ambient). They are also easily cleanable, since they are not attacked by organic solvents, acids and bases. These amorphous carbon materials, and materials in the DLC family such as fluorinated amorphous carbon (FDLC, a-F:C), silicon-containing amorphous carbon (SiDLC or SiCH), and SiCOH, are therefore expected to be preferable to SiO 2 and other existing mold materials because of their durability, ease of cleaning, and low stiction.