MEMS used in inertial sensors rely on the movement of mechanical elements, generally systems of masses and springs. Shielding these structures from particulate contamination requires encapsulating the MEMS structures. This encapsulation is typically accomplished by placing a silicon cap over the MEMS at the wafer level. In the event the device stops functioning as expected, it is necessary to visually inspect the MEMS structures. However, once the device is capped, the only way to visually inspect the sensor is to remove the cap using a destructive decapsulation process. Fortunately, product analysts can take advantage of the transmissive properties of infrared light through lightly doped silicon to examine MEMS structures through their silicon cap using IR microscopy. Although useful, the image quality of conventional IR microscopy has limitations resulting from the optics, geometry and detectors currently available. Recently, laser confocal microscopy techniques have been adapted to the infrared spectrum, offering improved image clarity and measurement capability. This paper reviews the use of conventional IR microscopy in imaging through silicon caps, the limitations of conventional IR microscopy in this application, and the new capabilities afforded by the use of laser confocal IR microscopy for through-cap imaging.
Virtual displays have tremendous potential in entertainment applications such as video games, head mount displays for personal computers, and mobile World Wide Web viewers. These consumer applications require high quality virtual displays at a cost below $40 per eye. This combination of performance and cost is not realizable with virtual displays based on LCDs or CRTs. However, low cost, high quality virtual displays can be achieved using patented scanned linear array technology and red, green and blue monolithic LED arrays. A 384 by 224 full color virtual display prototype has been built using this approach. The prototype delivers 4-bits of grayscale per color and flicker-free performance at a 60 Hz frame refresh rate. This paper discuses details of our LED based full color virtual display prototype; development of red, green and blue monolithic LED arrays; and work-in- progress to miniaturize the display and scale the resolution to full VGA.
Electronic still cameras capture images with CCDs instead of silver halide film. However, the laws of optics continue to apply, and the active area of the CCD must be located in the focal plane of the camera optics. Typically, this means that the CCD is actively aligned during camera assembly. It is desirable to avoid this alignment operation. One way of circumventing alignment is to assemble the CCD in a package with a reference surface that is mechanically coupled to the surface of the CCD. This reference surface can then be mated to the camera optics, and alignment is automatic. We have developed a Glass-on-Chip package that uses optical adhesives to bond a shaped piece of glass directly to the surface of a CCD after wire bonding. If the glass thickness is controlled, this package meets the requirements for passive alignment of CCD to optics. Properties of the adhesive are critical to the success of this approach. The adhesive must be optically transparent, heat curable and compatible with the polymeric color filters already on the CCD.
Conference Committee Involvement (7)
Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS, Nanodevices, and Nanomaterials XIII
3 February 2014 | San Francisco, California, United States
Reliability, Packaging, Testing, and Characterization of MOEMS/MEMS and Nanodevices XII
4 February 2013 | San Francisco, California, United States
Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS and Nanodevices XI
23 January 2012 | San Francisco, California, United States
Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS and Nanodevices X
24 January 2011 | San Francisco, California, United States
Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS and Nanodevices IX
25 January 2010 | San Francisco, California, United States
Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS and Nanodevices VIII
28 January 2009 | San Jose, California, United States
Reliability, Packaging, Testing, and Characterization of MEMS/MOEMS VII
21 January 2008 | San Jose, California, United States
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