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Jan 10th, 2011
Ziptronix accuses TSMC / Omnivision of Patent Infringement Over Oxide Bonding Technology
In December 2010 Ziptronix filed a complaint against TSMC and Omnivision in US District Court alleging “willful and deliberate” infringement of several Ziptronix patents pertaining to low temperature oxide bonding.
In question here is the use of oxide bonding for backside illumination in CMOS image sensors (CIS) , if such oxide surfaces are treated with plasma and/or other chemicals and if the Ziptronix patent claims pertaining to these processes are valid.
A recent market study by Yole Développement [see “CMOS Image Sensors Technologies & Markets - 2010”] has reported that most of the CIS manufacturers have moved, or are moving, to back side imaging (BSI) technology.
(Source: Yole Developpement, CMOS image sensor 2010 market report)
Sony introduced its CMOS BSI sensor technology in 2009 and now mass produces the CMOS BSI sensor in its newest video camcorders and digital still camera products. Casio, Nikon, Ricoh, Samsung, JVC and Fujifilm all separately announced their first digital camera products using a CMOS sensor based on BSI “Backside illumination” technology.
Cell phone camera image sensor market is moving to 1.1μm pixel architectures and CMOS BSI technology could also appear on some 1.4μm pixel sensor architectures in several smart-phone camera products soon. Omnivision, Aptina Imaging, Toshiba, Samsung and STMicro appear ready for BSI products.
Yole Développement expects BSI technology to be responsible for a little over $1B (~17% of CIS sales) in 2012.
Backside illumination (BSI) collects photons from the backside so the light enters the device unobstructed by the metal and dielectric layers of the interconnect structure.
TSMC and their subsidaries Xintec and VisEra have put infrastructure in place to deliver all needed unit operations as shown below :
Using oxide bonding for the “back-end, bonding to carrier step” would result in low temp, high throughput bonding with excellent CTE match and positional accuracy.
Ziptronix technology for BSI is centered around ZiBond™ which they claim allows one to achieve significantly higher bond energy between wafers after treatment with various surface “activating and terminating” processes. The direct oxide bonding, which is initiated at low temperature, is characterized by a very high bond energy between the surfaces.
In 2008 Ziptronix CEO Dan Donabedian fortold his December 2009 action when he said to i-Micronews: “Due to the broad and fundamental nature of Ziptronix patent's portfolio, I believe that any use of an oxide low temperature bonding process is highly likely to be covered by one or more of patents from the company. While there are commercial tools that support low temperature oxide bonding processes, Ziptronix has not granted, nor does it intend to grant any licenses under it’s IP to the manufacturers of this equipment. Anyone running a low temperature oxide bonding process as part of their manufacturing scheme is likely to be infringing on our IP” (here).
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