**Part 1**

**Electron and Ion Beam Lithography** 

**1** 

Sumio Hosaka *Gunma University* 

*Japan* 

**Electron Beam Lithography for Fine Dot Arrays** 

Recently, electron beam (EB) lithography has been applied to mask and reticle pattern draw, for fabricating semiconductor devices, and nanometer-sized pattern direct writing for developing of new concept nano-device. Mainly, the developing of practical EB drawing system has been started since 1960s, and fine pattern formation has also been studied together with the system development [1-3]. Regarding EB-drawn pattern size, at first, micron and submicron-sized pattern has been drawn on mask blank and directly on the device [4]. Today,

Especially, I have focused the EB lithography into the possibility to form fine dot and fine pitched dot 2-dimensional arrays for patterned media and quantum devices. The research has been done by dependences of resist material and thickness on drawing of fine dot arrays with nanometer-sized pitch in EB drawing, theoretically and experimentally. I have used Monte Carlo simulation and a conventional EB drawing system combined with scanning

In this chapter, I describe key factors such as resist type, resist thickness, proximity effect, etc for a formation of nanometer-pitch dot arrays, a limitation of the EB-drawn size theoretically and experimentally, and demonstrate the applications to dry-etching process

**2. Monte Carlo simulation of electron scattering in solid for EB lithography** 

Electron scattering in the resist and substrate is described based on its scattering angle, mean free path, energy loss, etc. Trajectories of incident electrons and energy deposition distributions (EDDs) in the resist are calculated. From the EDD, EB drawn resist dot profiles are estimated. The formation of nanometer sized pattern for electron energy, resist thickness and resist type can be studied. The EDD in 100 nm-thick resist on Si substrate were calculated for small pattern drawing. The calculations show that 4 nm-wide pattern will be formed when resist thickness is less than 30 nm. Furthermore, a negative resist is more

For the treatment of electron elastic scattering, the screened Rutherford scattering model [11]

the pattern size miniaturizes to nanometer-size of less than 20 nm in research [5, 6].

electron microscope (SEM) and EB drawing controller [7].

suitable than positive resist by the estimation of a shape of the EDD.

**2.1 Calculation model for Monte Carlo simulation of electron scattering** 

**1. Introduction** 

and nano-imprinting.

is employed as follow,

**[8]** 

**with Nanometer-Sized Dot and Pitch** 
