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Calculation method for diffractional field of double absorption layer attenuation phase-shift mask with auxiliary line

A technique of assisting lines and attenuating phase shift, which is applied in the field of calculation of the diffraction field of a double-absorbing layer attenuating phase-shift mask, which can solve the problem of solving the diffraction field that is not applicable to the double-absorbing layer attenuating phase-shift mask, and cannot analyze the diffraction of a multi-layer grating structure. , convergence problems, etc.

Active Publication Date: 2013-08-28
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

First, the method only analyzes multilayer grating structures with the same period
Second, this method analyzes the diffraction characteristics of dielectric gratings. When analyzing TM polarized light incident on a lossy mask grating, the convergence becomes poor
The prior art (LASERJOURNAL, 29, 3, 2008) introduces the design method of the sub-wavelength structure even beam Dammann grating based on strict coupled wave theory and genetic algorithm, but it cannot analyze the diffraction of multi-layer grating structure
[0012] Therefore, the above method is not suitable for solving the diffraction field of a double-absorbing layer attenuated phase-shift mask with auxiliary lines

Method used

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  • Calculation method for diffractional field of double absorption layer attenuation phase-shift mask with auxiliary line
  • Calculation method for diffractional field of double absorption layer attenuation phase-shift mask with auxiliary line
  • Calculation method for diffractional field of double absorption layer attenuation phase-shift mask with auxiliary line

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example 1

[0135] The standard 6% Ta / SiO is calculated here 2 Att.PSM, in the 45nm Line / Space (Line / Space) structure, after adding auxiliary lines, the diffraction efficiency and polarization degree of the 0 and 1 orders vary with the width of the mask auxiliary lines and the distance between the main feature pattern (crystal Scale on the circle) variation diagram. The wavelength is 193nm, normal incidence, and the mask duty ratio is 1 / 10. Unless otherwise specified, the width of the auxiliary lines is linewidth / 4, and the distance between the auxiliary lines and the main feature pattern is 2.2×linewidth, both of which are wafer scale. The refractive index, extinction coefficient and thickness of Ta are 1.63, 2.58 and 21nm., SiO 2 The refractive index, extinction coefficient and thickness are 1.63, 0.006 and 144 nm, respectively.

[0136] Figure 6 Ta / SiO 2After adding auxiliary lines to Att.PSM, the diffraction efficiency and degree of polarization of the diffraction order vary wit...

example 2

[0139] Here we calculate the standard 6% MoSi Att.PSM, 45nm line / space (Line / Space) structure, after adding auxiliary lines, the diffraction efficiency of 0 and 1 order, the degree of polarization with the line width (on the wafer Scale) change relationship diagram. The wavelength is 193nm, normal incidence, and the mask duty ratio is 1 / 10. In addition, the width of the auxiliary lines is linewidth / 4, and the distance between the auxiliary lines and the main feature pattern is 2.2×linewidth, both of which are on the wafer scale. The refractive index, extinction coefficient and thickness of MoSi are 2.343, 0.586 and 68nm respectively.

[0140] Figure 8 MoSi Att.PSM After adding auxiliary lines, the diffraction efficiency and polarization degree of the diffraction order vary with the feature size (scale on the wafer). (a) is the diffraction efficiency of 0th order when TE and TM are incident, (b) is the diffraction efficiency of 1st order when TE and TM are incident, (c) is ...

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Abstract

The invention provides a calculation method for a diffractinonal field of a double absorption layer attenuation phase-shift mask with an auxiliary line, which includes the following specific steps: step 1 setting the space harmonic number n when an electromagnetic field is expanded and determining grating coordinates; step 2 enabling dielectric constant of a grating layer containing the auxiliaryline to be in Fourier series expansion, and performing Fourier series expansion for dielectric constant reciprocal for TM polarized light; step 3 aiming at TE polarized light and the TM polarized light, solving characteristic matrix of every layer of grating, and then utilizing electromagnetic field tangential continuous boundary conditions to obtain the diffractinonal field corresponding to the TE polarized light. In step 2, the double absorption layer attenuation phase-shift mask with the auxiliary line serves as double-layer one-dimensional rectangular grating with a complex periodic structure, thereby being capable of analyzing diffraction of the double-layer subwavelength attenuation phase-shift mask with the auxiliary line.

Description

technical field [0001] The invention relates to the calculation of the diffraction field of a double-absorbing layer attenuation phase-shift mask with auxiliary lines, and belongs to the technical field of lithographic resolution enhancement. Background technique [0002] The rapid development of the semiconductor industry is mainly due to the progress of micro-processing technology in microelectronics technology, and photolithography technology is one of the most critical manufacturing technologies in chip preparation. Due to the continuous innovation of optical lithography technology, it has repeatedly broken through the expected optical exposure limit, making it the mainstream technology of current exposure. [0003] The lithography system is mainly divided into four parts: illumination system (light source), mask, projection system and wafer. The light incident on the mask is diffracted, and the diffracted light enters the projection system and forms an interference ima...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G03F1/32
Inventor 李艳秋杨亮
Owner BEIJING INSTITUTE OF TECHNOLOGYGY