Combination of Mass Metrology with Scatterometry to obtain bottom Width of deep Trenches : AM: Advanced Metrology

Haberjahn, Martin; Srichandan, Sasmita; Polak, Yulia; Ehrentraut, Georg; Heider, Franz

doi:10.1109/asmc54647.2022.9792504

Cited by 2 publications

(1 citation statement)

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“…Historically, inline measurements of DTI for process control have focused on the key parameter of trench depth because it has a direct impact of depth on breakdown voltage and latch-up suppression 1 , but differences in DTI architecture necessitate process control of sidewall profile, including the trench bottom width, most importantly. There have been non-destructive methods proposed to measure the bottom width of HAR deep trenches using hybrid methods involving "conventional" OCD and FTIR-based OCD, but these methods rely on complex hybrid schemes or model-less machine learning recipes requiring large amounts of destructive reference measurements for training 2,3 .…”

Section: Introductionmentioning

confidence: 99%

Non-destructive measurement of bottom width in deep trench isolation structures using IRCD metrology

Keller,

Poulingue,

Grynko

et al. 2024

Metrology, Inspection, and Process Control XXXVIII

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As scaling in semiconductor devices continues, the aspect ratios of deep trench isolation (DTI) structures have increased. DTI structures are used in power devices, power management ICs and image sensors as a method to isolate active devices by reducing crosstalk, parasitic capacitance, latch-up and allowing for an increase breakdown voltage of active devices. Measurement of these structures in high volume manufacturing (HVM), with non-destructive technology, has mostly been limited to the depth and top width of the DTI structure, while the bottom width (BCD) has not been able to be reliably measured. Here we present two different optical metrologies, "conventional" OCD and IRCD, that operate in the UV-VIS-NIR and MIR region of the electromagnetic spectrum, respectively, and discuss the measurability of DTI sidewall profile, bottom width, and depth in BCD (Bipolar CMOS DMOS) power management IC devices for each method at various pitches and line to space ratios. Experimental data will be presented showing sensitivity and discrimination of IRCD to a DOE specifically on the bottom width for three different structures.

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Section: Introductionmentioning

confidence: 99%