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Method for simulating a resist pattern in EB lithography with LER calculation

IP.com Disclosure Number: IPCOM000124060D
Publication Date: 2005-Apr-07
Document File: 5 page(s) / 67K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for simulating a resist pattern in electron beam (EB) lithography with line edge roughness (LER) calculation. Benefits include improved functionality and improved performance.

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Method for simulating a resist pattern in EB lithography with LER calculation

Disclosed is a method for simulating a resist pattern in electron beam (EB) lithography with line edge roughness (LER) calculation. Benefits include improved functionality and improved performance.

Background

              Conventional EB lithography simulators cannot simulate resist pattern profiles with LER information within a reasonable time because the calculation time is proportional to the exposed area.

      Conventional EB lithography simulation methods include the Direct Monte Carlo (DMC) and

Numerical simulation methods. The DMC method simulates the electrons corresponding to an exposure dose incident in the resist film in an exposed area. The method calculates the scatterings and the deposited energy within the resist film. The deposited energy distribution is converted to the dissolution rate distribution and developed to obtain a resist pattern profile (see Figure 1). 

      The Numerical method simulates the deposited energy of point-source electrons and fits them with a set of Gaussian functions, which are integrated for the patterned (exposed) area. Because the integration of the Gaussian functions can be obtained from taking difference of two error functions, deposited energy for exposed area is calculated very fast and independent of the exposure area (see Figure 2). However, this method is relatively inaccurate and can not reproduce any LER information.

General description

      The disclosed method is the simulation of a resist pattern in EB lithography with LER calculation. The method calculates accurate resist pattern profiles within a reasonable time even for a large pattern area.

      The EB simulation program consists of an interface unit (input simulation information), a deposited energy calculation unit (EB scattering calculation), and a development and pattern display unit.

      The disclosed method calculates deposited energy using two deposited energy calculation methods. One is accurate but slow. The other i...