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Overlay error measurement apparatus and method

A technology of overlay error and measuring device, which is applied in the field of equipment in the field of integrated circuit manufacturing, can solve the problems of small depth of focus, measurement wavelength cannot use wide band, and difficulty in focal plane control, so as to achieve limited measurement accuracy and rich effective measurement signals , to obtain short-term effects

Active Publication Date: 2016-01-27
SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] An object of the present invention is to solve the problem that the measurement wavelength cannot use a wide band when detecting overlay errors, so as to improve the adaptability of the measurement process
[0007] Another object of the present invention is to solve the problems of small depth of focus and difficult control of the focal plane when detecting overlay errors

Method used

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  • Overlay error measurement apparatus and method
  • Overlay error measurement apparatus and method
  • Overlay error measurement apparatus and method

Examples

Experimental program
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Embodiment 1

[0057] Please refer to figure 1 , figure 1 It is a schematic structural diagram of an overlay error measuring device according to Embodiment 1 of the present invention. The overlay error measurement device includes: a light source system; specifically, the light source system includes a light source 41 and a light source shaping system 43, and the light source is a broadband light source, for example, a white light source, or composed of several discrete spectral lines A composite light source, such as obtained by mixing several lasers with different wavelengths. The measurement light generated by the light source 41 is preferably a two-dimensional surface beam, that is, the cross-section 42 is a rectangle (not shown), and of course it can also be any other two-dimensional shape.

[0058] After passing through the light source shaping system 43 , the measuring light forms a one-dimensional line beam 44 from a surface beam. Please refer to figure 2 , which is a schematic...

Embodiment 2

[0062] Please refer to Figure 5 , which is a schematic structural diagram of the overlay error measuring device in Embodiment 2 of the present invention. For simplicity, in this embodiment, unless otherwise specified, the same components as in Embodiment 1 are given the same reference numerals, and their descriptions are omitted.

[0063] like Figure 5 As shown, the overlay error measurement device of this embodiment further includes a polarizer 416 and an analyzer 417 . The polarizer 416 is located between the light source system and the beam splitter 45 , so that the linear measurement beam 44 generates polarized light of TE mode or polarized light of TM mode after passing through the polarizer 416 . The analyzer 417 is added between the spectroscope 45 and the detector 411 in the measurement light path, so that the diffraction spectrum measurement signal 413 recorded can be the change of the TE mode reflectivity with the incident angle and wavelength, or can be the TM mo...

Embodiment 3

[0066] Please refer to Image 6 , which is a structural schematic diagram of the overlay error measuring device in Embodiment 3 of the present invention. For the sake of simplicity, in this embodiment, unless otherwise specified, the same components as in Embodiment 2 use the same symbols, and their descriptions are omitted.

[0067] The spatial frequency of each order of the diffracted light is sinθ=m×λ / p, where θ is the diffraction angle, m is the diffraction order, λ is the wavelength, and p is the period of the overlay mark. Since the measurement uses broadband light, within the same diffraction order, the diffracted light of each wavelength is spatially separated. In the present invention, the overlay error is determined by measuring the asymmetry of the diffracted light intensity at the same wavelength and the same incident angle. Therefore, it is necessary to accurately determine the position of the diffracted light of the same wavelength on the detector 411 . like ...

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Abstract

The invention discloses an overlay error measurement apparatus and method. The apparatus comprises a light source system, a spectroscope, a microscope objective, a lens assembly, a detecting raster and a detector; the power supply system provides a wide band linear measurement light beam; the reflective light, passing through the spectroscope, passes through the microscope objective to be projected on a measured-object to be reflected and diffracted, and the reflected and diffracted light passes through the microscope objective again to reach the detector to form a diffraction spectrum measurement signal; the transmission light, passing through a beam splitter, passes through the lens assembly to be projected on the detecting raster; the detecting raster is arranged in a tilted manner to enable the transmission light to be projected on the detecting raster; the returned plus one grade or minus one grade light passes through the lens assembly and the spectroscope in sequence to reach the detector to form a diffraction light monitoring signal; and a worktable can drive the measured object to rotate along the normal direction of the measured object. The overlay error measurement comprises the measurement for the same measured object before and after being rotated for 180 degrees to obtain asymmetry of light intensity, so that the measurement precision and the technological adaptability are improved, and the measurement error interference is reduced.

Description

technical field [0001] The invention relates to equipment in the field of integrated circuit manufacturing, in particular to an overlay error measurement device and method applied in photolithography measurement technology. Background technique [0002] According to the lithography measurement technology roadmap given by the International Technology Roadmap for Semiconductors (ITRS), as the key dimension (CD) of lithography pattern enters the process node of 22nm and below, especially the wide application of double patterning (Double Patterning) technology, the photo The measurement accuracy requirements of the engraving process parameter overlay (overlay) have entered the sub-nanometer field. Due to the limitation of the imaging resolution limit, the traditional Imaging-Based overlay measurement technology (IBO) based on imaging and image recognition (IBO) has gradually been unable to meet the requirements of new process nodes for overlay measurement. Diffraction-Based ove...

Claims

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Application Information

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IPC IPC(8): G03F7/20
Inventor 彭博方陆海亮王帆
Owner SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD