VLSI Research On The Exposure Of The Image

Lithography technique has been one of the key drivers for the semiconductor industry. Moore's law states that the number of devices on a chip doubles every 18 months. There are three main basics of the technology improvements that have kept the industry on this pace for more than 30 years. They are lithography, increased wafer size, and design. Roughly half of the density improvements have been derived from improvements in lithography. Lithography techniques mostly comprise exposure and etch phases. Exposure imaging's integrality and exactness are the basis of circuit reproduce. Character parameters include focus, resolution, critical dimension control, overlay and exposure uniformity, which can be used to depict imaging performance. Resolution and focus are both parameters, which restrict each other. The realization of critical dimension lies on resolution. Many lithography studies pay more attention to the advance of resolution, which is the primary driver. The controls of CD and overlay tolerance accelerate the advance of resolution at some certain extent. CD variation was set in a ±10 percent range , overlay tolerance is 1/3 of CD. High-resolution printed circuit can satisfy the demand of 30nm lithography. However, the limit of lithography is likely to be decided by CD control and economic. The project mainly analyzed the imaging effect of UV projection exposure, which base on optical image and CD variation mechanism. First, the aim of introducing Raleigh rule is to discuss actuality and trends of lithography technique, especially in advanced optical lithography aspects. Second, talking over resolution and focus is the center of thesis. Third, combining photo resist's line width variation forecast model with imaging factor to design experiment from all of angle such as lamp-house system, focus system, the aberration of mask and lens, photo resist, wafer flatness and thin film difference etc. The thesis aims at engineer application, which involved optics, microelectronics process, chemistry, polymer material science etc. We can grasp and supervise the way of experiment by basic theory. To very large degree, the experiments improve the effect of imaging and production performance.