An immediate application of the technology is for CMOS and CCD image sensors used in camera phones. Based on Tessera’s proven expertise in wafer-level technologies, Shellcase CF provides two critical benefits over conventional Chip-on-Board (COB) image sensor packaging construction:

1. A low-cost wire-bond assembly environment already installed globally and
2. Higher yields via the use of a novel encapsulation method.

Today, approximately half of all image sensors are packaged using COB technology. However, as image sensor resolution increases and pixel size decreases, achieving high yields with COB technology becomes very costly mainly due to particle contamination. This yield issue is problematic for cost-sensitive, high-volume consumer applications such as mobile phones and digital cameras.

Shellcase CF solves the yield challenge by combining the advantages of a glass cover applied at wafer level with the benefits of wire bond technology. With Shellcase CF technology, the image sensor's sensitive area is protected from particle contamination by a glass cover that is placed above the imager at the initial stage of wafer processing. The glass cover is elevated from the imager surface to allow the use of micro-lenses, thus enabling increased sensitivity of the imager. Bond pads are kept exposed for wire bonding at a later stage using existing wire-bond assembly lines.

Utilizing Shellcase CF technology provides up to 40 percent module yield improvement over COB technology, and as yield improves, the cost per module significantly declines. Because the image sensor is protected from contamination at the initial stage of wafer processing, Shellcase CF enables high assembly yields largely irrespective of the resolution of the imager or its pixel size.

As the complexity of camera modules increase, the need to protect the imager from contamination during module assembly also increases. Incorporating features like auto-focus and auto-zoom adds steps to the assembly process, thus increasing the susceptibility of the imager to particle fallout from the different elements incorporated in the module. By utilizing the glass cover in the Shellcase CF technology, the active area of the imager is kept protected from particles, thus achieving high assembly yield even for different camera modules.

Using Shellcase CF technology also enables wafer level testing with no danger of damaging or contaminating the imager, while continuous investment in assembly module line cleanliness can be avoided. This technology provides manufacturers the flexibility to do optical testing at the most favorable point of the assembly flow, as defined by their specific requirements and manufacturing environment.

Market Opportunities
Today, the prime application of Shellcase CF technology is for image sensors used in camera phones. Market research firm Techno Systems Research (TSR) forecasts that the market for camera phones will increase from approximately 387 million units in 2005 to approximately 825 million units in 2009, representing a 113% CAGR. Similarly, the market for image sensors within camera phones is also expected to experience significant growth, increasing from approximately 413 million units in 2005 to 940 million units in 2009, representing a 127% CAGR. TSR also projects that by 2009, nearly 80% of all mobile phones will integrate a camera.

Shellcase CF technology is also suitable for use with image sensors for many other high-volume consumer applications, including digital still cameras, video camcorders, PDAs, CCTV, and PC cameras. Forecasts show that these applications represent a combined total market of more than 250 million image sensor units by 2009.

Licensing Opportunities
A Tessera license for the Shellcase CF technology includes a full technology transfer of the process, procedures and equipment required to manufacture the technology, along with manufacturing rights to the intellectual property. Tessera is also offering its assistance in qualifying the line at the licensee's site.