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Overlay error measuring device and method

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

Active Publication Date: 2018-01-19
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 measuring device and method
  • Overlay error measuring device 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] Such as 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...

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 . Such as...

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Abstract

The invention discloses an overlay error measuring device and method. The device includes: a light source system, a beam splitter, a microscope objective, a lens group, a monitoring grating and a detector; the light source system provides a wide-band linear measuring beam, and the reflected light from the beam splitter is projected onto the measured object after passing through the microscope objective Reflection and diffraction occur, and reach the detector again through the microscope objective lens to form a diffraction spectrum measurement signal; the transmitted light through the beam splitter passes through the lens group and then projects on the detection grating, and the detection grating is placed obliquely so that the transmitted light is projected on the detection grating After being placed on the grating, the returned +1-level light or -1-level light sequentially passes through the lens group and the beam splitter to reach the detector to form a diffracted light monitoring signal; the workpiece table can drive the measured object to rotate around its normal direction. When measuring, it includes measuring the same measured object before and after 180° rotation to obtain the asymmetry of light intensity, thereby improving the measurement accuracy and process adaptability, and reducing the interference of measurement errors.

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 critical dimension (CD) of lithography patterns enters the process node of 22nm and below, especially the wide spread of double patterning (Double Patterning) technology application, the measurement accuracy requirements for overlay of photolithography process parameters 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 has gradually been unable to meet the requirements of new process nodes for overlay measurement. Diffraction-Based overlay ...

Claims

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Application Information

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