Hybrid scatterometry measurement for BEOL process control

Timoney, Padraig; Vaid, Alok; Kang, Byeong Cheol; Li, Haibo; Isbester, Paul; Cheng, Marjorie; Ng-Emans, Susan; Yellai, Naren; Sendelbach, Matt; Koret, Roy; Gedalia, Oram

doi:10.1117/12.2261452

Cited by 1 publication

(3 citation statements)

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“…Timoney et al discussed the substantial modeling complexities for M2 on fully integrated targets at the 7-and 14-nm nodes. 27 The incoming process variations can impact the measurement uncertainty and may lead to a significant measurement error of the features of interest. There are several pathways to a solution for the discussed scenarios, but they are coming with numerous disadvantages.…”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

“…Although a feedforward or hybrid model reduces the number of degrees of freedom, it still requires a complex geometric optical model that includes data from either previous or other measurement steps. 24,25,27,28 Another variation of hybrid metrology is related to "differential modeling," which requires measurements before and after the process step of interest along with appropriate algorithms. 29 There are certain constraints, and the methodology does not necessary simplify the solution.…”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

“…There are several pathways to a solution for the discussed scenarios, but they are coming with numerous disadvantages. Although a feedforward or hybrid model reduces the number of degrees of freedom, it still requires a complex geometric optical model that includes data from either previous or other measurement steps 24 , 25 , 27 , 28 . Another variation of hybrid metrology is related to “differential modeling,” which requires measurements before and after the process step of interest along with appropriate algorithms 29 .…”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

See 2 more Smart Citations

Spectral interferometry for fully integrated device metrology

Schmidt¹,

Medikonda²,

Rizzolo³

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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A spectral interferometry technique called vertical travelling scatterometry (VTS) is introduced, demonstrated, and discussed. VTS utilizes unique information from spectral interferometry and enables solutions for applications that are infeasible with traditional scatterometry approaches. The technique allows for data filtering related to spectral information from buried layers, which can then be ignored in the optical model. Therefore, using VTS, selective analyses of the topmost part of an arbitrarily complex stack are possible within a single metrology step. This methodology helps to overcome geometrical complexities and allows for focusing on parameters of interest through dramatically simplified optical modeling. Such model simplifications are specifically desired for back-end-of-line applications. Three examples are monitored discussed: (i) the critical dimensions (CDs) of a first metal level on top of nanosheet gate-all-around transistor structures, (ii) the thickness of an interlayer dielectric above embedded memory in the active area, and (iii) the CDs of trenches on top of tall stacks in the micrometer range comprising many layered dielectrics. It was found that, in all three cases, data filtering through VTS allowed for a simple optical model capable of delivering parameters of interest. The validity and accuracy of the VTS solution results were confirmed by extensive reference metrology obtained by traditional scatterometry, scanning electron microscopy, and transmission electron microscopy. Furthermore, it was shown that machine learning models trained with VTS filtered data can converge to a robust solution with a smaller dataset compared with models training with traditional scatterometry data.

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Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%