Density Multiplication and Improved Lithography by Directed Block Copolymer Assembly
Ricardo Ruiz, Huiman Kang, François A. Detcheverry, Elizabeth Dobisz, Dan S. Kercher, Thomas R. Albrecht, Juan J. de Pablo, Paul F. Nealey
Electronic devices such as computer chips and future data storage drives that are the heart of products from laptops to cell phones to digital cameras are manufactured using photolithography. This process allows for the patterning of billions of nanoscopic structures and parts of the devices with virtually no defects over areas of square centimeters. As we look into the future, limitations related to the tools and materials used in the lithographic process may preclude the realization of future generations of high-performance products.
A team of researchers at the University of Wisconsin Nanoscale Science and Engineering Center and Hitachi Global Storage Technologies have recently developed the technology to dramatically improve the quality and decrease the cost of patterning at nanoscopic length scales. Self-assembling block copolymers, materials that spontaneously form structures at length scales of 5 to 50 nm, assembly on surfaces patterned with lithography so as to markedly improve both the quality and resolution of the process. In comparing the assembled structures to the lithographically defined chemical pattern (see Figure), the density is increased by a factor of four and the dimensional uniformity is vastly improved. These results have profound implications for augmenting and advancing the performance and capabilities of lithographic patterning and the many essential modern devices that rely on this nanomanufacturing process.
Figure. Comparison of the quality and resolution of patterns created by lithographic tools using current materials and processes (A and B) versus patterns created using the same tools but with self-assembling block copolymer materials (C, D).