All-Directional Dual Pixel Auto Focus Technology in CMOS Image Sensors

Shim, Eun Sub; Lee, Kyung-Ho; Pyo, Junghyung; Choi, Wooseok; Yun, Jungbin; Jung, Taesub; Lee, Kyungduck; Kim, Seyoung; Lee, Chanhee; Baek, Seungki; Kim, Hyuncheol; Choi, Sungsoo; Yang, Jun-Seok; Son, Kyoungmok; Choi, Jong-Won; Park, Howoo; Kim, Bum Suk; Ahn, Jin-Hyun; Chang, Donghoon

doi:10.23919/vlsicircuits52068.2021.9492472

Cited by 7 publications

(2 citation statements)

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“…6(b) and (c). The improved crosstalk level is quite close to that of the most recently reported state-of-the-art CMOS image sensors (15.0-16.3 %) [37], [38], [39].…”

Section: Rearrangement Of the Color Pr Coating Ordersupporting

confidence: 85%

In-Depth Study of 3D Color-Resist Coating Process for Optically Uniform Image Sensors

et al. 2021

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The color filter required for manufacturing a CMOS image sensor was redeveloped to optimize its optical uniformity. An in-depth study of the three-dimensional (3D) coating process and how it gives rise to various radial-shaped striation patterns was conducted. These radial-shaped striation patterns were systematically investigated with reference to two types of patterns: the orthogonal type found only at the orthogonal edges of the wafer and the diagonal type found mostly at the corner of each quadrant. The formation of the orthogonal pattern was based on the wide standing wave created by the incident force of the spreading color photoresist (PR) and the reflective force from the bump pads acting as coating barriers. The diagonal pattern was found to be generated by the turbulent wakes created behind the bump pads by the drag force, which interfered with the coating flow. An in-depth study using Ansys CFX software and an inline inspection tool revealed that lowering the viscosity of the color PR material is a key factor for improving the phenomenon whereby the 3D striation patterns of the orthogonal and diagonal types are formed. Based on this finding, it was possible to drastically reduce the formation of the 3D striation patterns by decreasing the viscosity of the material comprising each color PR. This study provides not only an empirical and theoretical understanding of the 3D color PR coating mechanism, but also guidelines for future color filter processes.

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“…6(b) and (c). The improved crosstalk level is quite close to that of the most recently reported state-of-the-art CMOS image sensors (15.0-16.3 %) [37], [38], [39].…”

Section: Rearrangement Of the Color Pr Coating Ordersupporting

confidence: 85%

In-Depth Study of 3D Color-Resist Coating Process for Optically Uniform Image Sensors

et al. 2021

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“…In order to get a good image in a dark environment, it can be used like a big pixel by binning the signal of the surrounding pixels [3]. Although this method reduces the number of pixels of an image, it has the advantage of increasing FWC, sensitivity and DR and enabling all-pixel Phase Detection Auto Focus (PDAF) [4,5]. However, as the number of pixels to be binning increases, the FWC and Dual Conversion Gain ratios increase, which leads to image quality degradation.…”

Section: Introductionmentioning

confidence: 99%

World's first 16:4:1 triple conversion gain sensor with all-pixel AF for 82.4dB single exposure HDR

ChangHyun¹,

Lee²,

EunSub³

et al. 2022

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A Triple Conversion Gain (TCG) sensor with all-pixel auto focus based on 2PD of 1.4 um-pitch has been demonstrated for mobile applications. TCG was implemented by sharing adjacent Floating Diffusion (FD) without adding other capacitor. TCG helps to reduce the noise gap or slow the noise increase as user gain increases. An image with a Dynamic Range (DR) of 82.4 dB through a single exposure can be obtained through intra-scene TCG (i-TCG).Through this, a wider range of illuminance environments can be captured in the image. In addition, a more natural image can be obtained by reducing the SNR dip in one image by using TCG.

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