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Overlay measuring mark and method

A technology for marking and measuring results, applied in the field of lithography, it can solve the problem that the measurement accuracy cannot meet the requirements, and achieve the effects of improving the accuracy and robustness, the measurement model is accurate, and the calculation is economical.

Active Publication Date: 2013-12-18
SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The traditional imaging-based overlay measurement technology is increasingly unable to meet the requirements in terms of measurement accuracy, especially due to the problem of tool-induced shift (TIS) caused by the measurement tool, making the measurement uncertainty reach several nanometers. order of magnitude, so it is necessary to find a new measure of overlay size

Method used

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  • Overlay measuring mark and method
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  • Overlay measuring mark and method

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Experimental program
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Effect test

no. 1 approach

[0025] figure 1 A schematic of the scatterometry is shown. The light source 11 emits the probe light. In the spectral scatterometer, the light source is generally a white light source; in the angle-resolved scatterometer, the light source is generally a monochromatic light source, or a composite light source composed of some discrete spectral lines. The detection light is projected onto the sample 13 to be tested through the detection light path 12 . Samples are generally periodic semiconductor patterns, such as photoresist gratings on silicon wafers, or etched grooves, hole arrays, etc. These graphics include a certain topographical structure 18, which can be characterized by period (Pitch), parameters HT (height), SWA (side wall steepness) and Mid-CD (middle line width), etc. The purpose of scattering measurement is to determine these Parameter. After the detection light is reflected / scattered by the sample, it is collected by the measurement optical path 14, and the coll...

no. 2 approach

[0039] This embodiment changes the design of the measurement marks on the basis of the first embodiment, such as Figure 4 shown. The measurement marks have different film systems in the x direction, and A, B, C, and D in the figure correspond to the regions of four different film systems. The first mask mark 51 is used to expose the grating structure in the first process layer, and the second mask mark 52 is used to form the grating structure in the third process layer. The glue grating areas have overlapping parts in the x direction. 53 is a sectional view of the entire measurement mark in the y direction. The measurement marks and the marks of the first embodiment can be placed in different scribed grooves on the silicon wafer.

[0040] The measurement process of CD topography and overlay error is the same as in the first embodiment. Firstly, the D area is measured to obtain the thickness of each layer of film system, n, k value (refractive index); secondly, the A and C ...

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Abstract

The invention provides an overlay measuring mark. The mark is divided into a first region, a second region, a third region and a fourth region on an x-y surface and is provided with a plurality of medium layers on the z direction, wherein the first region and the second region have first grating structures, the second region and the third region have second grating structures, the fourth region does not have a grating structure, the first grating structure and the second grating structure are respectively located on different medium layers and have the same period, and the overlay error between the first grating structure and the second grating structure is d. By using the mark, the CD (Compact Disc) feature and the overlay error can be measured more easily and simultaneously.

Description

technical field [0001] The invention relates to the field of photolithography, in particular to marks and methods for overlay measurement. Background technique [0002] With the continuous reduction of critical dimensions of semiconductor devices, especially the introduction of double patterning technology, the requirements for overlay accuracy are more stringent. Taking the 32nm technology node as an example, the overlay accuracy is 5.7nm, and its measurement accuracy is generally 1 / 10 of the overlay accuracy, that is, 0.57nm. The traditional imaging-based overlay measurement technology is increasingly unable to meet the requirements in terms of measurement accuracy, especially due to the problem of tool-induced shift (TIS) caused by the measurement tool, making the measurement uncertainty reach several nanometers. order of magnitude, so it is necessary to find a new measurement method for overlay size. [0003] An overlay measurement method based on scatterometry technol...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G03F7/20
Inventor 张青云
Owner SHANGHAI MICRO ELECTRONICS EQUIP (GRP) CO LTD