In order to form a circuit pattern of electronic parts, for example, a semiconductor device and a display, and so on, a lithography technique has been used in which the pattern is fabricated by exposing a resist to light through a photomask and developing the resist. Under the present circumstances, with a growing demand for microfabrication, shortening the wavelength of a light source and increasing the size of an optical projection system have been proceeded to improve resolution. The resolution can further be improved by using an immersion technique, a super-resolution technique, and chemical mechanical polishing (CMP). However, according to the microfabrication by top-down approach, which has been the mainstream technique thus far, expensive apparatuses and materials need to be used for a smaller processing size, leading to requirement of massive investments.
On the other hand, studies of bottom-up techniques such as use of self-assembly of molecules have been developing. From the viewpoint of affinity with semiconductor processes, lithography using self-assembled patterns of a block copolymer as masks has been attracting a lot of attention. The present inventors have proposed a method of forming a pattern using a block copolymer as a template based on a difference in dry etching resistance between the blocks. However, it is found that patterns in the order of 10 nm or less are hard to be formed by only using the difference in dry etching resistance between the two blocks.
Further, in order to use the block copolymer for patterning wires of, for example, a semiconductor memory, patterns of the block copolymer need to be aligned in predetermined positions in a self-assembled manner. Thus, the studies have been made to achieve the needs. That is, considering the application to fabrication of semiconductor devices, only particular portions of the patterns of the block copolymer, such as those portions corresponding to wires, need to be removed by some means of exposure and other methods.
USPTO Backgrounds
USPTO Backgrounds