Method for estimating patterns to be printed on a plate or mask by means of electron-beam lithography and corresponding printing device

Patent metadata

Field	Value
Publication number	US-9430597-B2
Application number	US-201314100484-A
Country	US
Kind code	B2
Filing date	Dec 9, 2013
Priority date	Dec 21, 2012
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

This method for estimating patterns (M′ PF ,D′ PF ) to be printed by means of electron-beam lithography, comprises the following steps: printing ( 100 ), in a resin, a set of calibration patterns (M CF , D CF ); measuring ( 120 ) characteristic dimensions (CD) of this set; supplying an estimation ( 140 ) of the point spread function (PSF) based on the characteristic dimensions (CD) measured; estimating ( 160 ) the patterns (M′ PF ,D′ PF ) to be printed by convoluting the point spread function (PSF) supplied with an initial value of the patterns (M PF ,D PF ).
Furthermore, each calibration pattern printed includes a central zone exposed to the electron beam and a plurality of surrounding concentric zones with rotational symmetry. The characteristic dimensions measured are characteristic dimensions (CD) of the central zones of the patterns. The estimation of the point spread function (PSF) is calculated by inverting analytical modelling of the effect, on these characteristic dimensions, of applying the first point spread function portion (PSF BE ) characterising electrons back-scattered by the substrate to the set of calibration patterns (M CF , D CF ).

First claim

The invention claimed is:

1. A method for estimating patterns to be printed on a plate or mask by electron-beam lithography, comprising the following steps:
printing with electron-beam lithography, in a resin arranged on a substrate, a set of calibration patterns
measuring characteristic dimensions of the set of calibration patterns after printing, and saving said characteristic dimensions to memory,
executing a program on a processing module, having access to the memory, to supply an estimation of the point spread function characterising electrons scattered during printing, based on the characteristic dimensions measured,
estimating the patterns to be printed by convoluting the point spread function supplied with an initial value of these said patterns to be printed, wherein:
each calibration pattern printed in the resin includes a central zone exposed to the electron beam and a plurality of concentric zones with rotational symmetry arranged about this central zone,
the characteristic dimensions measured after printing are characteristic dimensions of the central zones of the patterns, and
the executing a program on a processing module comprises estimating the point spread function by calculating the sum of a first point spread function portion characterising electrons back-scattered by the substrate and a second point spread function portion characterising electrons scattered in the resin, and performing an inversion of analytical modelling of the effect, on said characteristic dimensions, of applying the first point spread function portion to the set of calibration patterns.

2. The method for estimating patterns to be printed as claimed in claim 1 , wherein the executing a program on a processing module comprises application of the first point spread function portion to the set of calibration patterns is by modelling analytically by the product of a matrix modelling the set of calibration patterns with a vector modelling the first point spread function portion, the analytical modelling being inverted by inverting the matrix modelling the set of calibration patterns.

3. The method for estimating patterns to be printed as claimed in claim 2 , wherein the executing a program on a processing module comprises matrix modelling the set of calibration patterns using a square matrix of order n that models a set of n patterns with n concentric zones, each row of the matrix corresponding to one of the calibration patterns and each column of the matrix corresponding to one of these concentric zones.

4. The method for estimating patterns to be printed as claimed in claim 3 , wherein the executing a program on a processing module comprises matrix modelling the set of calibration patterns using a Hadamard matrix.

5. The method for estimating patterns to be printed as claimed in claim 4 , wherein executing a program on a processing module comprises defining the first point spread function portion characterising the electrons back-scattered by the substrate, annotated PSF BE , by the following expression:

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Assignees

• Commissariat A L'Energie Atomique Et Aux Ene Alt
• Aselta Nanographics
• Commissariat L Energie Atomique Et Aux Energies Alternatives

Inventors

• Belledent Jerome

Classifications

• H01J2237/31769

  Proximity effect correction · CPC title

• G03F1/82

  Auxiliary processes, e.g. cleaning or inspecting · CPC title

• H01J37/3174

  Particle-beam lithography, e.g. electron beam lithography · CPC title

• G03F7/70491

  Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes · CPC title

• G03F7/2061

  Electron scattering (proximity) correction or prevention methods · CPC title