CN-121540094-B - Method for measuring surface profile of nanostructure

CN121540094BCN 121540094 BCN121540094 BCN 121540094BCN-121540094-B

Abstract

The invention relates to a surface profile measuring method of a nano structure, which comprises the following steps of S100, constructing a scattering intensity calculation model of the target nano structure, S200, carrying out a small-angle X-ray scattering experiment on a sample with the target nano structure to obtain scattering experiment data of the target nano structure, and S300, fitting the scattering intensity calculation model by utilizing the scattering experiment data to obtain key structure parameters of the target nano structure. The surface profile measuring method of the nano structure does not need complex sample pretreatment, has the advantages of non-destructiveness, high efficiency and high accuracy, and provides a brand new technical scheme for high-precision measurement of the nano structure in the field of semiconductor manufacturing.

Inventors

PAN NAN
YANG CHUNMING
BIAN FENGGANG
QIN XUYANG
GAO XINHAO
HONG CHUNXIA
HUANG YUYING

Assignees

中国科学院上海高等研究院

Dates

Publication Date: 20260508
Application Date: 20260121

Claims (5)

1. A method of measuring a surface profile of a nanostructure, comprising the steps of: S100, constructing a scattering intensity calculation model of a target nanostructure, wherein the scattering intensity calculation model comprises key structural parameters for describing the surface profile; s200, carrying out a small-angle X-ray scattering experiment on a sample with the target nanostructure so as to obtain scattering experiment data of the target nanostructure; s300, fitting the scattering intensity calculation model by using the scattering experimental data to obtain key structural parameters of the target nanostructure; the step S100 specifically includes the following steps: S110, establishing a structural model of the target nanostructure, wherein the structural model is formed by repeatedly translating a polygonal unit along the horizontal direction and the vertical direction, the polygonal unit is formed by splicing a plurality of square scattering units, the polygonal unit comprises a first side, a second side, a third side, a fourth side, a fifth side and a sixth side which are sequentially connected end to end, the first side, the third side and the fifth side are all parallel to the horizontal direction, the second side, the fourth side and the sixth side are all parallel to the vertical direction, the length of the first side is a multiplied by L 0 , the length of the second side is m multiplied by L 0 , the length of the third side is n multiplied by L 0 , the length of the fourth side is (m-b) multiplied by L 0 , the length of the fifth side is (a-n) multiplied by L 0 , the length of the sixth side is b multiplied by L 0 , wherein the length of the first side is a multiplied by a coefficient of the scattering unit, the length of the second side is m multiplied by n, the length of the fourth side is multiplied by a coefficient of the fourth side is the length coefficient of the fourth side is the coefficient of the key coefficient, and the key coefficient of the structure is included; S120, determining the shape factor of the scattering unit based on a kinematic diffraction theory; S130, determining the scattering intensity of the polygonal unit based on the structural model of the target nanostructure and the shape factor of the scattering unit; s140, determining a structural factor based on the periodicity of the target nanostructure; s150, determining a scattering intensity calculation model of the target nanostructure based on the structural factors and the scattering intensities of the polygonal units; The form factor of the scattering unit satisfies the following relation: , , , , Wherein f 0 is the shape factor of the scattering unit, q is a scattering vector, q is a mode of the scattering vector, q x 、q y is a component of the scattering vector in a horizontal direction and a vertical direction, respectively, half of a scattering angle in a small-angle X-ray scattering experiment, lambda is the wavelength of X-rays in the small-angle X-ray scattering experiment, and alpha is the rotation angle of a sample; The scattering intensity of the polygon unit satisfies the following relation: , , , , Wherein, the Is the scattering intensity of the polygonal unit, For the scattering intensity of a rectangle with the first and sixth sides as long and wide, For the scattering intensity of a rectangle with the second and third sides as length and width, For the scattering intensity of a rectangle with the third side and the sixth side as length and width, N is the serial number of the scattering unit; The structural factor satisfies the following relation: , wherein S is the structural factor, X is the period of the target nanostructure in the horizontal direction, Y is the period of the target nanostructure in the vertical direction, delta is the Dirac function, j is the diffraction order index in the horizontal direction, and k is the diffraction order index in the vertical direction; The scattering intensity calculation model of the target nanostructure meets the following relation: I= ×S, Wherein I is the scattering intensity of the target nanostructure.
2. The method of claim 1, wherein the critical structural parameters include a, b, m, n and X, and the scattering experimental data includes a scattering intensity distribution of q x -q y plane of the sample having the target nanostructure.
3. The method of measuring a surface profile of a nanostructure according to claim 2, wherein the step S300 comprises the steps of: S310, extracting an experimental scattering intensity curve of which q y =0 and q x is in a preset range from the scattering experimental data; And S320, fitting the key structural parameters by using an experimental scattering intensity curve with q y =0 and q x in a preset range to obtain an optimal solution of the key structural parameters.
4. The method of claim 3, wherein the step S320 specifically comprises: And iteratively adjusting the key structural parameters by using one of a differential evolution algorithm, a genetic algorithm and a particle swarm algorithm to minimize the mean square error of a scattering intensity curve and an experimental scattering intensity curve, which are predicted by the scattering intensity calculation model and are q y =0 and q x in a preset range, until a convergence criterion is met, so as to obtain an optimal solution of the key structural parameters.
5. The method of claim 1, wherein the target nanostructure is a nanograting or a nanofield-effect tube having a periodic concave-convex structure.

Description

Method for measuring surface profile of nanostructure Technical Field The invention relates to the technical field of semiconductors, in particular to a method for measuring the surface profile of a nano structure. Background At the moment of rapid development of semiconductor technology, feature sizes of electronic devices in integrated circuits are continuously shrinking, and conventional planar transistors are gradually transformed into three-dimensional complex architectures. In the semiconductor manufacturing link, accurate measurement of parameters such as Critical Dimension (CD), line Edge Roughness (LER), surface profile and the like of a nano structure is a core element for guaranteeing stable device performance and improving production yield. Currently, the commonly used nanostructure measurement techniques mainly include Scanning Electron Microscopy (SEM), atomic Force Microscopy (AFM), and scatterometry. Scanning Electron Microscopy (SEM) can measure Critical Dimension (CD) and Line Edge Roughness (LER) by virtue of high resolution, but high-energy electron beams are easy to damage a sample, and have limitation on the accurate characterization capability of a three-dimensional complex surface structure, atomic Force Microscopy (AFM) can acquire high-precision three-dimensional morphology information, but has low measurement speed, so that rapid characterization of a large-area sample is difficult to realize, and a scatterometry has the characteristic of nondestructivity, but has insufficient detail resolution capability of extremely fine nano features. As the feature sizes of nanostructures continue to shrink, these traditional measurement methods increasingly expose a number of limitations while meeting practical measurement requirements. The critical dimension small angle X-ray scattering (CD-SAXS) technology is used as an emerging nano metering means, and has the remarkable advantages of non-destructiveness, nano-scale sensitivity, large-area statistical characterization capability and the like. However, most of the existing researches focus on the cross-sectional profile of the grating, so that the attention on high-precision measurement of surface profile parameters directly influencing the performance of a device is less, and meanwhile, the support of a systematic model based on a kinematic diffraction theory is lacking, so that the requirement of the semiconductor manufacturing field on high-precision measurement of a nano surface structure is difficult to meet. Therefore, how to develop a method capable of efficiently and precisely measuring the surface profile of a nanostructure (such as a nanograting, a nanowire, or a nano field effect transistor) is a problem that needs to be solved by those skilled in the art. Disclosure of Invention The invention aims to provide a method for measuring the surface profile of a nano structure so as to realize high-efficiency and high-precision measurement. Based on the above object, the present invention provides a method for measuring a surface profile of a nanostructure, comprising the steps of: S100, constructing a scattering intensity calculation model of a target nanostructure, wherein the scattering intensity calculation model comprises key structural parameters for describing the surface profile; s200, carrying out a small-angle X-ray scattering experiment on a sample with the target nanostructure so as to obtain scattering experiment data of the target nanostructure; And S300, fitting the scattering intensity calculation model by using the scattering experimental data to obtain key structural parameters of the target nanostructure. Optionally, step S100 specifically includes the following steps: S110, establishing a structural model of the target nanostructure, wherein the structural model is formed by repeatedly translating a polygonal unit along the horizontal direction and the vertical direction, the polygonal unit is formed by splicing a plurality of square scattering units, the polygonal unit comprises a first side, a second side, a third side, a fourth side, a fifth side and a sixth side which are sequentially connected end to end, the first side, the third side and the fifth side are all parallel to the horizontal direction, the second side, the fourth side and the sixth side are all parallel to the vertical direction, the length of the first side is a multiplied by L 0, the length of the second side is m multiplied by L 0, the length of the third side is n multiplied by L 0, the length of the fourth side is (m-b) multiplied by L 0, the length of the fifth side is (a-n) multiplied by L 0, the length of the sixth side is b multiplied by L 0, wherein the length of the scattering unit is a multiplied by the length of the first side, the length of the second side is multiplied by the length of the fourth side, and the length of the fourth side is multiplied by the length of the sixth side is multiplied by b; S120, determining the shape fact