Sony to Debut 'Stacked' CMOS Image Sensor

Aug 22, 2012
Jyunichi Oshita, Nikkei Electronics
The "IUS014F-Z" module (left) comes with embedded autofocus and image quality adjustment functions as well as the "ISX014" sensor (center).
The "IUS014F-Z" module (left) comes with embedded autofocus and image quality adjustment functions as well as the "ISX014" sensor (center).
[Click to enlarge image]
An image taken by the IUS014F-Z (left) and an image taken by Sony's existing product (right)
An image taken by the IUS014F-Z (left) and an image taken by Sony's existing product (right)
[Click to enlarge image]

Sony Corp will release what it claims is the industry's first back-illuminated CMOS image sensor that uses a "stacked structure."

The announcement was made Aug 20, 2012. Sony will release three models of the CMOS sensor, "Exmor RS." And they have higher sensitivities and wider dynamic ranges than the company's existing products. Also, Sony will start to ship three modules equipped with those sensors in October 2012.

Sony expects that the new CMOS sensor will be used for mobile devices such as smartphones and tablet computers and employed for smartphones to be launched at the end of 2012. In the image sensor market, in which about 1.5 billion units were shipped in fiscal 2011, the company aims to ship 100 million units of the new sensor per year, said Yasuhiro Ueda, senior general manager, Image Sensor Business Division, Semiconductor Business Group, Professional, Device & Solutions Group, SVP, Corporate Executive, Sony.

The Exmor RS back-illuminated CMOS sensor has a structure in which the sensor (image pickup device) part and the logic circuit part, which is for signal processing, are separated and three-dimensionally stacked. For the 3D stacking, a technique similar to TSV (through silicon via) is used, Ueda said.

The structure not only contributed to the small size and high image quality of the CMOS sensor but enabled to embed various functions (that were externally attached to devices in the past) in the logic circuit part of the CMOS sensor. Sony explained this concept at a press conference that it organized in January 2012.

The three models to be launched by Sony are the 1/3.06-inch "IMX135" with a pixel count of 13.13 million, the 1/4-inch "IMX134" with a pixel count of 8.08 million and the 1/4-inch "ISX014" with a pixel count of 8.08 million. The pixel pitch of the three models is 1.12μm, which the company claims is the smallest in the industry.

The IMX135 and IMX134 have the "RGBW coding function" and "HDR (high dynamic range) movie function" in their logic circuit parts.

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