Solid-State Imaging Device Electrode Pad Spacing and Filter Uniformity
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Solution Overview
Problem
Existing solid-state imaging devices face challenges in achieving uniformity of optical filters, such as color filters, due to uneven application methods, leading to degradation in imaging properties and the generation of longitudinal streaks in image readings.
Innovation Solution
A solid-state imaging device design featuring a specific arrangement of electrode pads and optical filters, where the pads are spaced closely enough to prevent unevenness in the filter application, using a multilayer interconnection and spin coating method to ensure even surfaces for the filters, which are applied in a way that they face photodiodes through an insulating film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light-sensitive resin is applied using a spin coating method to form color filters, then the filters can be formed on the semiconductor substrate, but uneven application occurs leading to non-uniform filters and degradation in imaging properties
Solution Approach 1:
The patent applies a planarization layer (spin-on-glass) before applying the light-sensitive resin to pre-level the surface. This preliminary action removes surface irregularities that would cause uneven resin application, ensuring uniform color filter formation while maintaining the simplicity of the spin coating process.
2Area of stationary object
If electrode pads are arranged closely together to reduce device area, then the device size is reduced, but unevenness in filter application occurs leading to longitudinal streaks in images
Solution Approach 1:
The planarization layer is applied in advance to level the surface around closely-spaced electrode pads before resin application. This preliminary surfacing action prevents the pads from causing uneven resin flow and subsequent longitudinal streaks, enabling close pad spacing without sacrificing filter uniformity.
3Productivity
If the space between electrode pads is reduced to increase pixel density, then more imaging elements can be packed, but the resin application becomes uneven causing streaks in image readings
Solution Approach 1:
By applying the planarization layer before the light-sensitive resin, the patent creates a uniformly flat surface that allows resin to flow evenly even when electrode pads are closely spaced. This enables higher pixel density while preventing the resin unevenness that would otherwise cause longitudinal streaks in captured images.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures the production of optical filters with even surfaces, reducing degradation in imaging properties and preventing longitudinal streaks, thereby enhancing the quality of color image reading.
Implementation Method 1
a film forming method named a spin coating method is used as in the case where an interlayer insulating film or a photoresist used for patterning is formed
Data Source
AI summary
A solid-state imaging device includes a substrate having a rectangular shape; a first region configured to extend on the substrate in a length direction of the substrate, and to include a plurality of electrode pads arranged above the substrate through a multilayer interconnection; and a second region configured to extend in the length direction, and to include an imaging element, an optical filter, and an insulating film. The second region extends on the substrate on which the imaging element is arranged. The optical filter is arranged above the substrate and faces the imaging element through the insulating film. The second region extends in parallel to the first region to be apart from the first region by a given distance. The plurality of electrode pads are arranged to be apart from each other by a given space, equal to or smaller than the given distance, in the length direction.