Optical method for depth measurement of high aspect ratio 3D microstructure

Zizheng, Wang; Chengpei, Bai; Xinlei, Sun; Chunguang, Hu

doi:10.1117/12.2687231

Cited by 1 publication

(1 citation statement)

References 12 publications

(10 reference statements)

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“…Established toolsets available commercially ("conventional" OCD) have an operation wavelength range from the DUV to the NIR (approximately 193 to 1000nm with extensions into the NIR). For deep trenches (deeper than 10µm), measuring depth using normal incidence spectroscopic reflectometry is a wellestablished metrology, with reports in literature of measurement capability to measure aspect ratios exceeding 50:1 and greater than 400µm in depth 10 . The measurement of sidewall profile of deep trenches has proven to be far more difficult, with non-destructive measurements requiring complex hybrid schemes or exotic machine learning requiring lots of destructive reference for training.…”

Section: Issues With Measurement Of Har Deep Trenches By "Conventiona...mentioning

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: Issues With Measurement Of Har Deep Trenches By "Conventiona...mentioning

confidence: 99%