Dielectric Grid for Back Side Illumination Sensors

The patent divides the back side surface into a grid pattern of transparent and opaque regions. The dielectric grid structure segments the light paths, allowing light to pass through transparent regions while blocking cross-talk in opaque regions. This segmentation resolves the contradiction by enabling back-side light entry for sensitivity while preventing harmful reflection and cross-talk through spatial division.

The patent applies different optical properties to different regions of the back side surface. The dielectric grid creates localized transparent regions for light entry and opaque regions for light blocking. This local differentiation of optical quality allows the sensor to achieve high light sensitivity where needed while preventing cross-talk in specific areas, resolving the contradiction between sensitivity and harmful optical effects.

The patent combines the dielectric grid formation with existing manufacturing steps such as color filter deposition or lens formation. By merging the grid creation into already-present process steps, the patent achieves high quantum efficiency through the high-k dielectric material while minimizing additional manufacturing complexity. The grid is formed as part of the existing multi-layer structure rather than as a separate complex process.

The patent utilizes the high-k dielectric property of specific materials to achieve enhanced quantum efficiency. By selecting materials with high dielectric constants and optimizing their thickness and pattern dimensions, the patent improves light convergence and blocking performance. These parameter optimizations are achieved through standard deposition and lithography processes, avoiding excessive manufacturing complexity while achieving the desired reliability improvement.

The patent forms the dielectric grid structure before final sensor assembly and testing. By preparing the light convergence structure in advance during the manufacturing process, the patent ensures precise light path control is built into the device architecture. This preliminary formation of the optical structure allows for optimized light convergence precision while enabling parallel processing of other device components, thereby reducing overall manufacturing cycle time.

The patent designs the dielectric grid structure to serve multiple functions simultaneously: it blocks cross-talk, converges light to photodiode regions, and provides mechanical support. By creating a multi-functional structure, the patent achieves precise light convergence without requiring separate dedicated components for each function. This reduces the total number of manufacturing steps and materials needed, thereby decreasing manufacturing cycle time while maintaining high precision.