Deep trench isolation enables device scaling in BCD power management ICs and improves overall performance.
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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Presented at SPIE Advanced Lithography 2024. Nick Keller* a), Marc Poulingue a), Ross Grynko a), Troy Ribaudo a) , G. Andrew Antonelli a), Victor Li a), Marcello Ravasio b), Delphine Le Cunff.
a) Onto Innovation Inc. b) STMicroelectronics
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