Ultimately accurate SRAF replacement for practical phases using an adaptive search algorithm based on the optimal gradient method

Kawahara

2019

Elect Comm in Japan

In semiconductor device manufacturing process, it is necessary to measure overlay error between integrated layers. As semiconductor process design rules continue to shrink, small overlay error comes to lead to the fatal fault of the device electrical property. As a result, the needs for the dense overlay measurement in the chip with the use of circuit pattern increase. We propose an automatic extraction technique of the evaluation points (EPs) that are suitable for the overlay measurement by scanning electron microscopy using design data of the device pattern layout. The proposed algorithm extracts all measureable patterns by evaluation of the positional relationship between a segment pair on the upper and lower layers by plural selection indices. Simulation was performed to estimate the overlay error distribution within the shot area using the EPs automatically extracted by the proposed method. The standard deviations of estimation errors in the x-and y-directions were 0.06 nm and 0.10 nm (3ó), respectively. It was confirmed that distortion in the exposure apparatus can be estimated automatically and highly accurately. K E Y W O R D Sautomation, design data, overlay measurement, scanning electron microscope (SEM) 36

Section: Extraction Of Evaluation Pointsmentioning

confidence: 99%

Section: Extraction Of Evaluation Pointsmentioning

confidence: 99%

Section: Extraction Of Evaluation Pointsmentioning

confidence: 99%

Section: F I G U R E 8 Element Indicator Values For Ep Extractionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Automatic extraction technique of CD‐SEM evaluation points to measure semiconductor overlay error

Kawahara

2019

Elect Comm in Japan

Automatic Generation of Imaging Sequence for CD‐SEM Using Design Data

Matsuoka

2016

Elect Comm in Japan

Critical dimension scanning electron microscope (CD-SEM) is widely used as a measurement tool of semiconductor patterns. It is necessary to set imaging sequence including corrections of imaging position and focusing of electron beam for the reliable measurement. Conventionally, addressing point (AP) and autofocus point (AF) suitable for these processing are selected by the hand and this is a drop factor of SEM operation rates. We propose a technique to generate imaging sequence from design data of the pattern layout. Proposed method calculates selection indices for pattern complexity, uniqueness, and so on from design data and selects AP and AF templates automatically based on these indices. For 901 evaluation points, success rate of SEM imaging by proposed method was 100% and generation time of imaging sequence was 18 minutes. Compared with manual selection (conventionally, it takes 10 several hours by using SEM), large reduction of operation cost can be realized. C⃝ 2016 Wiley Periodicals, Inc. Electron Comm Jpn, 99(9): 62-71, 2016; Published online in Wiley Online Library (wileyonlinelibrary.com).

Generation of large field SEM image by panorama composition technology for nano-order measurement

Hojyo

2016

Meas. Sci. Technol.

Semiconductor manufacturing has a pressing need for a method to accurately evaluate the global shape deformation of a photomask pattern. We thus propose a novel composition technique for a large field panorama image of scanning electron microscopy (SEM). The proposed method optimises the arrangement of segmented imaging regions (SIRs), which are components of a panorama image, on the basis of the design data of the photomask pattern layout. The quantity of the line pattern segment, which is a clue to the connection in an overlapping region between adjoining SIRs and the connectability of any two SIRs, is evaluated. As a result of the optimisation, it is guaranteed that all SIR images can be connected theoretically. For 30 evaluation points, the maximum connection error of the SIR images was 1.5 nm in a simulation using pseudo-SEM images. The maximum total measurement error, which includes the connection error and CD measurement error from the panorama image, is estimated at 2.5 nm. This error was equivalent to about 1.4% of the photomask line width (target: 3%). The experiments using real SEM images demonstrate the effectiveness of the proposed method. It was visually confirmed that a large field, highresolution and seamless panorama image can be generated.