Three-dimensional CMOS image sensor with 4x64 pixel array

An active pixel sensor (APS) in a digital X-ray detector is the dominant circuitry for a CMOS image sensor (CIS) despite its lower fill factor (FF) compared to that of a passive pixel sensor (PPS). Although the PPS provides higher FF, its overall signal-to-noise ratio (SNR) is lower than that of the APS. The required high resolution and small focal plane can be achieved by reducing the number of transistors and contacts per pixel. We proposed a novel passive pixel array and a high precision current amplifier to improve the dynamic range (DR) without minimizing the sensitivity for diagnostic compact digital X-ray detector applications. The PPS can be an alternative to improve the FF. However, size reduction of the feedback capacitor causes degradation of SNR performance. This paper proposes a novel PPS based on readout and amplification circuits with a high precision current amplifier to minimize performance degradation. The expected result was attained with a 0.35-μm CMOS process parameter with power supply voltage of 3.3 V. The proposed PPS has a saturation signal of 1.5 V, dynamic range of 63.5 dB, and total power consumption of 13.47 mW. Therefore, the proposed PPS readout circuit improves the dynamic range without sacrificing the sensitivity.

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Comprehensive Hygro-Thermo-Vapor Pressure Model for CMOS Image Sensor

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.419-420.493 ◽

2009 ◽

Vol 419-420 ◽

pp. 493-496

Author(s):

Hsiang Chen Hsu ◽

Li Ming Chu ◽

Lih Shan Chen ◽

Shen Li Fu

Keyword(s):

Vapor Pressure ◽

Moisture Absorption ◽

Three Dimensional ◽

Moisture Diffusion ◽

Cmos Image Sensor ◽

Image Sensor ◽

Mechanical Analysis ◽

Element Analysis ◽

Swelling Properties ◽

Moisture Expansion

A combined effect of moisture diffusion, heat transfer, and hygro-thermo-vapor pressure modeling for pre-mold QFN CMOS Image Sensor (CIS) package has been developed in this study. Hygroscopic swelling properties such as saturation, coefficient of moisture expansion (CME) and activation energy can be extracted through TMA (Thermal Mechanical Analysis) and TGA (Thermal Gravitational Analysis) instruments. Fick’s second law of transient diffusion is solved by using finite element analysis (FEA) to evaluate the overall moisture distributions. With obtained experimental data, a three-dimensional FEA CIS model using the “thermal-wetness” technique is developed to predict the moisture absorption, moisture desorption, temperature distributions, hygro-thermo-vapor pressure mechanical coupled effect and the residual stress distributions at JEDEC pre-conditioning standard JESD22-A120.

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Megapixel CMOS image sensor fabricated in three-dimensional integrated circuit technology

ISSCC. 2005 IEEE International Digest of Technical Papers. Solid-State Circuits Conference, 2005. ◽

10.1109/isscc.2005.1494016 ◽

2005 ◽

Cited By ~ 62

Author(s):

V. Suntharalingam ◽

R. Berger ◽

J.A. Burns ◽

C.K. Chen ◽

C.L. Keast ◽

...

Keyword(s):

Integrated Circuit ◽

Three Dimensional ◽

Cmos Image Sensor ◽

Image Sensor ◽

Three Dimensional Integrated Circuit ◽

Circuit Technology

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Reliability of SnAgCu Alloys for CMOS Image Sensor QFN Package under Thermal Cycling Loading

Materials Science Forum ◽

10.4028/www.scientific.net/msf.594.175 ◽

2008 ◽

Vol 594 ◽

pp. 175-180

Author(s):

Hsiang Chen Hsu ◽

Hui Yu Lee ◽

Wen Lo Shieh

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Three Dimensional ◽

Region Of Interest ◽

Element Model ◽

Cmos Image Sensor ◽

Image Sensor ◽

Computational Time ◽

Mesh Density ◽

Good Agreement

A three-dimensional finite element model of CMOS image sensor QFN packaging using ANSYS codes is developed to investigate the solder joint reliability under thermal cycle test. The predicted thermal-induced displacements were found to be very good agreement with the Moiré interferometer experimental in-plane deformations. The developed finite element model is then applied to predict fatigue life of Sn4.0Ag0.5Cu, Sn3.5Ag0.5Cu and Sn3.9Ag0.6Cu alloys based on JEDEC standard JESD22-A104. In order to save computational time and produce satisfactory results in the region of interest, an independent more finely meshed so-called submodel scheme based on cut-boundary displacement method is generated. The mesh density for different area ratio of refinery/coarse model was verified and the results were found to be good agreement with previous researches. The modified Coffin-Manson equation and strain energy density based equation are applied to evaluate the reliability of SnAgCu alloys. A series of comprehensive parametric studies were conducted in this paper.

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