Manufacturability and Stress Issues in 3D Silicon Detector Technology at IMB-CNM

Optical inspection of 1191 silicon micro-strip sensors was performed using a custom made optical inspection setup, employing a machine-learning based approach for the defect analysis and subsequent quality assurance. Furthermore, metrological control of the sensor's surface was performed. In this manuscript, we present the analysis of various sensor surface defects. Among these are implant breaks, p-stop breaks, aluminium strip opens, aluminium strip shorts, surface scratches, double metallization layer defects, passivation layer defects, bias resistor defects as well as dust particle identification. The defect detection was done using the application of Convolutional Deep Neural Networks (CDNNs). From this, defective strips and defect clusters were identified, as well as a 2D map of the defects using their geometrical positions on the sensor was performed. Based on the total number of defects found on the sensor's surface, a method for the estimation of sensor's overall quality grade and quality score was proposed.

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“…The warp shape is the result of the mechanical stress induced on the silicon wafer during different manufacturing and polishing steps [12,13].…”

Section: Warp Measurementmentioning

confidence: 99%

Optical inspection of the silicon micro-strip sensors for the CBM experiment employing artificial intelligence

Lavrik

Shiroya

Schmidt

et al. 2022

Nuclear Instruments and Methods in Physics Research Section A:

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“…This structure reduces the loss of charge carriers due to trapping effects, the charge collection time, and the voltage for full depletion, compared to planar silicon detectors [34]. The isolated radiation sensitive volume (SV) has been fabricated using MEMS technology optimized for years at IMB-CNM [35][36][37][38] and mimics the shapes and microscopic sizes of mammalian cells of few micrometers of diameter. More information about the Frontiers in Physics frontiersin.org readout chip (ROC, or application-specific integrated circuit, ASIC) in order to analyze the signals individually (bottom of Figure 2B).…”

Section: Microdosimetry Systemsmentioning

confidence: 99%

Multi-arrays of 3D cylindrical microdetectors for beam characterization and microdosimetry in proton therapy

et al. 2022

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The present work shows the performance of two new large microdosimetry multi-array systems having two different configurations, namely, pixel and strip configurations. They cover radiation sensitive areas of 1.9 cm × 0.1 cm and 5.1 cm × 0.1 cm, respectively. The microdosimetry systems are based on arrays of 3D cylindrical silicon microdetectors. The 3D electrodes are etched inside the silicon and have a 25 μm diameter and a 20 μm depth. Each of these unit cells is completely isolated from the others and has a well defined 3D micrometric radiation sensitive volume. The pixel-type device consists of 25 × 5 independent silicon-based detectors (500 in total), each one connected to a readout channel, collecting information in 2D in the transverse planes to the particle beam direction. The distance between the individual detectors (pitch) is 200 μm in the horizontal axis and 250 μm in the vertical one. In the case of the strip-type system, we have 512 “columns” (or strips) of 10 detectors per column. Each strip is connected to a readout channel, giving us information in one dimension, but with better statistics than a single pixel. In this system, both the horizontal and vertical pitches are 100 μm.Both systems have been tested under proton beam irradiations at different energies between 6 and 24 MeV to obtain the corresponding microdosimetry quantities along the Bragg peak and distal edge. The measurements were performed at the Accélérateur Linéaire et Tandem à Orsay (ALTO, France). The microdosimetry quantities were successfully obtained with spatial resolutions of 100–250 μm. Experimental results were compared to Monte Carlo simulations and an overall good agreement was found. Both microdetector systems showed a good microdosimetry performance under clinical-equivalent fluence rates along distances of several centimeters. This work demonstrates that the two new systems having different configurations can be clinically used as microdosimeters for measuring the lineal energy distributions in the context of proton therapy treatments. Additionally, they could be also used for beam monitoring.

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“…However, none of the existing systems (commercial or experimental) have spatial resolution along the transverse beam direction and of a data acquisition adaptation for clinical conditions. In order to improve the current silicon-based microdosimeters, a new 3D-cylindrical architecture of silicon-based radiation detectors was designed in 2012 and eventually manufactured in 2015 31 , 37 by using micro manufacturing techniques optimized for 3D detectors that had been developed by Pellegrini et al during the previous decade in the Radiation Detectors group of the National Center of Microelectronics (IMB-CNM, CSIC), Spain 38 – 40 . Compared to planar silicon detectors, the 3D architecture reduces the loss of charge carriers due to trapping effects, the charge collection time, and the voltage for full depletion 41 – 43 .…”

Section: Introductionmentioning

confidence: 99%

Microdosimetry performance of the first multi-arrays of 3D-cylindrical microdetectors

Bachiller‐Perea

Zhang

Fleta

et al. 2022

Sci Rep

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The present work reports on the microdosimetry measurements performed with the two first multi-arrays of microdosimeters with the highest radiation sensitive surface covered so far. The sensors are based on new silicon-based radiation detectors with a novel 3D cylindrical architecture. Each system consists of arrays of independent microdetectors covering 2 mm$$\times$$ × 2 mm and 0.4 mm$$\times$$ × 12 cm radiation sensitive areas, the sensor distributions are arranged in layouts of 11$$\times$$ × 11 microdetectors and 3$$\times$$ × 3 multi-arrays, respectively. We have performed proton irradiations at several energies to compare the microdosimetry performance of the two systems, which have different spatial resolution and detection surface. The unitcell of both arrays is a 3D cylindrical diode with a 25 $$\mu$$ μ m diameter and a 20 $$\mu$$ μ m depth that results in a welldefined and isolated radiation sensitive micro-volume etched inside a silicon wafer. Measurements were carried out at the Accélérateur Linéaire et Tandem à Orsay (ALTO) facility by irradiating the two detection systems with monoenergetic proton beams from 6 to 20 MeV at clinical-equivalent fluence rates. The microdosimetry quantities were obtained with a spatial resolution of 200 $$\mu$$ μ m and 600 $$\mu$$ μ m for the 11$$\times$$ × 11 system and for the 3$$\times$$ × 3 multi-array system, respectively. Experimental results were compared with Monte Carlo simulations and an overall good agreement was found. The good performance of both microdetector arrays demonstrates that this architecture and both configurations can be used clinically as microdosimeters for measuring the lineal energy distributions and, thus, for RBE optimization of hadron therapy treatments. Likewise, the results have shown that the devices can be also employed as a multipurpose device for beam monitoring in particle accelerators.

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Manufacturability and Stress Issues in 3D Silicon Detector Technology at IMB-CNM

Cited by 18 publications

References 48 publications

Optical inspection of the silicon micro-strip sensors for the CBM experiment employing artificial intelligence

Optical inspection of the silicon micro-strip sensors for the CBM experiment employing artificial intelligence

Multi-arrays of 3D cylindrical microdetectors for beam characterization and microdosimetry in proton therapy

Microdosimetry performance of the first multi-arrays of 3D-cylindrical microdetectors

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