Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Reexamination Certificate
1998-04-30
2001-08-14
Arroyo, Teresa M. (Department: 2881)
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
C250S492200, C250S492220
Reexamination Certificate
active
06274877
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electron beam exposure apparatus and, more particularly, to an electron beam exposure apparatus for drawing a pattern on a wafer or drawing a pattern on a mask or reticle using a plurality of electron beams.
2. Description of the Related Art
In an electron beam exposure apparatus which performs exposure by imaging an electron beam on a substrate, when the beam current is large, the electron beam image projected onto the substrate is blurred due to a Coulomb effect. Most of blurring caused by the Coulomb effect can be corrected by re-adjusting the focal point position of a reduction electron optical system for projecting an electron beam, but some blurring remains uncorrected. In a variable shaping exposure apparatus which shapes the sectional shape of an electron beam within a maximum range of about 10 &mgr;m×10 &mgr;m, the blurring produced by the Coulomb effect is predicted from the area of the shaped beam, and apparatus parameters (beam current density, half beam incident angle, beam acceleration voltage, and optical length of the reduction electron optical system), and the focal point of the reduction electron optical system is adjusted in accordance with the prediction result.
In a multi-electron beam exposure apparatus which irradiates an array of a plurality of electron beams in line onto a substrate, deflects these electron beams to scan the substrate, and draws a pattern by ON/OFF-controlling the electron beams to be irradiated in correspondence with the pattern to be drawn, since the electron beams are dispersed i.e., since the effective current density per unit area on the substrate is low, blurring due to the Coulomb effect is small. This means that when the blurring due to the Coulomb effect is confined within a predetermined value, the multi-electron beam exposure apparatus can improve the exposure throughput by applying larger beam currents than the variable shaping exposure apparatus.
SUMMARY OF THE INVENTION
It is an object of the present invention to allow high-resolution pattern drawing by appropriately correcting an electron beam image blurred due to the Coulomb effect.
An electron beam exposure apparatus according to one aspect of the present invention is an electron beam exposure apparatus for forming a pattern on a substrate by exposure using a plurality of electron beams, comprising an electron beam source for generating a plurality of electron beams in accordance with a pattern to be exposed, a reduction electron optical system for imaging an electron beam group emitted by the electron beam source on the substrate, a scanning unit for scanning the electron beam group on the substrate, and a correction unit for correcting imaging positions of the electron beam group on the basis of correction data corresponding to the pattern to be exposed.
In the electron beam exposure apparatus, the correction unit preferably corrects the imaging positions of the electron beam group on the basis of correction data corresponding to the number of electron beams that make up the electron beam group emitted by the electron beam source.
In the electron beam exposure apparatus, the correction unit preferably corrects the imaging positions of the electron beam group on the basis of correction data corresponding to a distribution of electron beams that make up the electron beam group emitted by the electron beam source.
In the electron beam exposure apparatus, the correction unit preferably adjusts a focal point position of the reduction electron optical system on the basis of the correction data.
In the electron beam exposure apparatus, the electron beam source preferably comprises an electron source, a plurality of elementary electron optical systems for forming intermediate images of the electron source, and a control unit for controlling whether each of the plurality of elementary electron optical systems forms an intermediate image of the electron source.
In the electron beam exposure apparatus, the correction unit preferably adjusts imaging positions of the intermediate images in an axial direction of the reduction electron optical system on the basis of the correction data.
In the electron beam exposure apparatus, the correction unit preferably adjusts imaging positions of the intermediate images in an axial direction of the reduction electron optical system, and a focal point position of the reduction electron optical system on the basis of the correction data.
In the electron beam exposure apparatus, preferably, a subarray is formed by a matrix of a plurality of elementary electron optical systems and an entire array is formed by a matrix of a plurality of subarrays.
In the electron beam exposure apparatus, the correction unit preferably corrects imaging positions of the intermediate images in an axial direction of the reduction electron optical system in units of subarrays on the basis of the correction data.
In the electron beam exposure apparatus, preferably, the correction unit commonly corrects imaging positions of electron beams coming from all the elementary electron optical systems of the entire array by adjusting a focal point position of the reduction electron optical system on the basis of the correction data, and adjusts imaging positions of the intermediate images in an axial direction of the reduction electron optical system in units of subarrays on the basis of differences between the common correction amount and appropriate correction amounts.
In the electron beam exposure apparatus, preferably, the scanning unit comprises a main deflector and sub deflector for deflecting electron beams emitted by the electron beam source, the scanning unit divides an exposure region on the substrate into a plurality of fields, switches the field to be exposed by the main deflector, and scans the electron beam group in each field using the sub deflector, and a constant correction amount for imaging positions of the electron beam group is maintained while a pattern is drawn on each field.
In the electron beam exposure apparatus, the correction unit preferably dynamically corrects imaging positions of the electron beam group emitted by the electron beam source on the basis of the correction data.
In the electron beam exposure apparatus, the correction unit preferably corrects the imaging positions of the electron beam group on the basis of the correction data each time a positional relationship between the electron beam group emitted by the electron beam source and the substrate is settled.
In the electron beam exposure apparatus, the correction data is preferably a function having, as variables, at least the number of electron beams coming from the subarray corresponding to an object to be corrected, a distance between the subarray corresponding to the object to be corrected, and another subarray that outputs the electron beams, and the number of electron beams coming from the other subarray.
In the electron beam exposure apparatus, the correction data is preferably a function having, as a variable, at least a spacing of electron beams emitted by the electron source.
The electron beam exposure apparatus preferably further comprises a calculation unit for generating correction data used for correcting imaging positions of the electron beam group on the basis of data that defines the pattern to be exposed on the substrate.
An electron beam exposure method according to another aspect of the present invention is an electron beam exposure method for forming a pattern on a substrate by exposure using a plurality of electron beams, comprising the steps of: imaging a plurality of electron beams, which are emitted by an electron beam source in accordance with a pattern to be exposed, via a reduction electron optical system, and scanning the electron beam group on the substrate; and correcting imaging positions of the electron beam group on the basis of correction data corresponding to the pattern to be exposed in synchronism with the scan.
In the electron beam exposure method, the c
Arroyo Teresa M.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Wells Nikita
LandOfFree
Electron beam exposure apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Electron beam exposure apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electron beam exposure apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2538295