Genya Matsuoka

A high‐speed, high‐precision electron beam lithography system (electron optics)

A variably shaped electron beam exposure system HL‐600 has been developed for both direct wafer writing and mask making. It was designed as a high‐throughput tool to cover lithography requirements down to a 0.5 μm linewidth. To achieve this high‐throughput capability, many newly developed techniques were adopted in the electron optics and in the control electronic circuits. The simplified electron beam column consists of only four magnetic lenses. The magnetic deflection for main field scanning was enlarged so as to reach up to 6.5 mm sq in order to reduce the overhead time associated with work stage movement. In addition, the design of an objective lens system with a small aberration, and an algorithm for deflection aberration correction were developed. Automatic measurement of defocusing and astigmatism aberrations at a number of sample points were performed by taking through focusing, and the third order polynomial correction function of deflection was determined. As a result, the edge resolution for t...

Electron optical column for high speed nanometric lithography

Abstract An electron beam lithography system has been developed for the fabrication of nanometric level devices. The system has the ability of 0.1um resolution, ±0.04um overlay accuracy and 1 wafer/hr throughput. Key technologies used in the system are a newly developed field emission cathode, a variable gaussian optics and a three stage deflection system.

Technological capability and future enhanced performance of HL-7000M

HL-7000M electron beam lithography system has been developed as a state-of-the-art reticle writer for the generation of 90nm node production and 65nm node development. It is capable of handling relatively large volume data files such as full Optical Proximity Correction patterns and angled patterns for System on Chip. Aiming at technological requirements, a newly designed electron optics column generating a vector-scan variable shaped beam and a digital disposition system with a storage area network technology have been integrated into HL-7000M. Since the requirement on the critical dimension uniformity is extremely demanding on the ITRS roadmap, HL-7000M has also needed to improve its beam shaping performance. The ability relevant to shaping beam size has a great impact on its line width or critical dimension accuracy. To reduce an aberration caused within the shaping lens system, the dual quadrupole electrostatic shaping deflector has been utilized. By applying advanced technologies, HL-7000M with a result of critical dimension uniformity (2.5nm and 2.8nm in 3σ) has achieved meeting its target requirement of the 90nm generation for production. Additionally HL-7000M has proved its potential, allowing the industry to establish quickly the processes further beyond the requirements of the 65nm node for development.

Automatic electron beam metrology system for development of very large‐scale integrated devices

A computer‐controlled electron beam metrology system has been developed which is capable of measuring a large number of features automatically. The system also evaluates the distribution of critical dimensions (CD) on a wafer in order to promote submicron very large‐scale integrated process technology. This system provides nondestructive measurement in a semiconductor production line by using a low voltage electron beam from a field emission gun. The system consists of a computer‐controlled optical column, a precise X‐Y stage controlled by a laser interferometer, high‐accuracy electronic circuits and a control computer. The system places submicron patterns under the electron beam within a ±0.05 μm deviation and measures them step‐by‐step under the optimum beam conditions. Repeatability is 0.008 μm with a throughput of 100 features/h.

Mark detection in electron beam lithography using evaluation of wave signal symmetry

Abstract A new mark detection method has been developed using the symmetry of mark signals. The calculation of the symmetry is executed by a digital signal processor in order to reduce the detection time to less than 100 msec. Detection accuracy is estimated by a simulator. Calculated accuracy is compared with experiment results. The detection system is adopted in a new electron beam lithography system (1) .

Progress in EB-cell projection lithography

Abstract The throughput and accuracy of electron beam cell projection lithography are discussed. The method drastically reduces the number of e-beam exposure shots utilizing a specially shaped beam. A system designed to produce 64 and 256M-DRAMs is introduced. A 0.2 μm exposed pattern is also shown.

Digital Processing Of Beam Signals In A Variably Shaped Electron Beam Lithography System

This paper discusses signal processing procedures which have been developed for three important beam adjustments required by variably shaped electron beam lithography systems: dynamic focussing adjustment, deflection distortion correction and beam size adjustment. Precise and speedy measurement of edge slope, beam position and beam size are all necessary in this context. To execute these measurements, backscattered electron signals are stored in a buffer memory following digital scanning of a shaped beam across a fiducial mark. These signals are then digitally processed in a control computer. These procedures have been applied to an EB lithography system (HL-600). Pattern accuracy of 0.2 μm over a 6.5x6.5 mm field and overlay accuracy of 0.1 μm were obtained.

Improved Image Placement Performance of HL-7000M

HL-7000M electron beam (EB) lithography system has been developed as a leading edge mask writer for the generation of 90 nm node production and 65 nm node development. It is capable of handling large volume data files such as full Optical Proximity Correction (OPC) patterns and angled patterns for System on Chip (SoC). Aiming at the technological requirements of the International Technology Roadmap for Semiconductors (ITRS) 2002 Update, a newly designed electron optics column generating a vector-scan variable shaped beam and a digital disposition system with a storage area network technology have been implemented into HL-7000M. This new high-resolution column and other mechanical components have restrained the beam drift and fluctuation factors. The improved octapole electrostatic deflectors with new dynamic focus correction and gain alignment methods have been built into the object lens system of the column. These enhanced features are worth mentioning due to the achievement of HL-7000Ms Image Placement (IP) performance. Its accuracy in 3σ of a 14 x 14 global grid matching result over an area of 135 mm x 135 mm measured by Leica LMS IPRO are X: 6.09 nm and Y: 7.85 nm. In addition, the shot astigmatism correction has been in the development and testing process and is expected to improve the local image placement accuracy dramatically.

Technologies for electron-beam reticle writing systems for 130-nm node and below

A new advanced e-beam reticle writing system HL-950M has been developed to meet requirements for the production of 130 nm node reticles as well as the development of 100 nm node reticles. In order to improve the critical dimension (CD) accuracy and pattern positioning accuracy, several new technologies have been introduced. Fine address size is realized by a newly developed control electronics that enables the system to handle address unit of 2.5 nm, providing four times higher resolution than that of the previous systems. Reconstruction of sub-sub-field (SSF) pattern data has been developed so that the same pattern is exposed twice with reconstructed SSF pattern data sets with different SSF boundaries, realizing better stitching and positioning accuracy. High accuracy proximity effect correction has been developed with a new second order proximity effect calculation scheme, particularly promising better CD linearity. As main results of the system evaluation, the global CD accuracy of 9 nm and the global pattern positioning accuracy of 15 nm have been obtained. The overall performance of the HL-950M system has satisfied the specifications required for the 130 nm node reticle production and 100nm node reticle development.

A High Speed Nanometric Electron Beam Lithography System

An electron beam lithography system has been developed for research and development of fine structure advanced devices. The system is capable of 0.1 um resolution, 0.04 um stitching accuracy, 0.04 um overlay accuracy and 1 wafer/hr throughput. One of key technologies used in this system is a variable gaussian optics and a pattern edging-process. This makes it possible to realize ten times higher throughput than the conventional fixed gaussian beam method and provide a simple means of proximity correction.