James J Jacob

Title: Innovations of James J Jacob

Introduction

James J Jacob is a notable inventor based in Aptos, CA (US). He has made significant contributions to the field of optical systems and photomask metrology. With a total of 6 patents to his name, Jacob's work has advanced the capabilities of imaging technologies.

Latest Patents

One of Jacob's latest patents is titled "Architectures for high-resolution photomask phase metrology." This invention discloses several instrument architectures for measuring arbitrary phase retardation on advanced lithography photomasks. The architectures combine traditional interferometric techniques with high-magnification UV microscopy. Features are interrogated using a multitude of phase probes, formed by imaging a number of variable apertures back-illuminated by phase-coherent beams onto the surface of the photomask with a given demagnification. The size, spacing, and orientation of the phase probes may be adjusted to suit photomask feature geometries. Means are provided to vary the relative optical phase between the phase probes. These phase probes both reflect from and transmit through the photomask. The stationary, non-localized interference fringes formed in the regions of phase probe electric field overlap contain information on the optical path difference between the two probes. The spatial resolution of these measurements is limited only by the resolution limit of the UV microscope, which may significantly exceed the capability of existing tools.

Another significant patent is "Apparatus for beam homogenization and speckle reduction." This invention greatly improves the quality of images obtained using optical systems illuminated by coherent light. It does so by removing the undesirable pseudo-random variations in the final image due to interference speckle and inhomogeneities in the spatial intensity distribution of the light source. A bundle of light-guiding fibers is interposed between the illumination source and the imaging system. Non-uniform propagation within the fiber bundle creates a pseudo-random phase variation across the illumination beam, which gives rise to a dynamic interference speckle pattern superimposed upon the desired image acquired by the optical system. Rotating the fiber bundle around the axis of propagation, whilst simultaneously integrating the output of the photosensitive detector over a period of time, substantially removes variations due to source inhomogeneities and coherent interference.

Career Highlights

Throughout his career, Jacob has worked with various companies, including Actinix. His innovative contributions