Solid-State Image Sensor Embedding Film Thickness Control
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Solution Overview
Problem
Existing methods for manufacturing solid-state image sensors with optical waveguides face issues of increased light leakage due to thick embedding films, which require additional steps like CMP to adjust film thickness, increasing manufacturing cost and reducing yield.
Innovation Solution
A method involving the application of a photosensitive material to a multilayered wiring layer, exposure, and a development step to reduce and adjust the film thickness in the pixel region without adding extra processing steps, using techniques such as hydrophilization and water-washing to ensure even thickness reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the photosensitive material is applied to form an embedding film with sufficient thickness to embed the optical waveguide, then the optical waveguide can be properly embedded, but the film thickness becomes too large causing color filters and microlenses to be distant from the optical waveguide, increasing light leakage
Solution Approach 1:
The patent applies a thick photosensitive material layer in advance to ensure proper embedding of the optical waveguide, then uses light exposure and development to selectively remove excess material. This preliminary application of excess material followed by selective removal allows the embedding function to be fulfilled while achieving the desired final thickness to prevent light leakage.
Solution Approach 2:
The patent extracts the excess photosensitive material from the embedding film through a development process. By exposing the photosensitive material to light and then developing, the unnecessary portions are removed, leaving only the required thickness that maintains both proper waveguide embedding and close proximity to color filters and microlenses to prevent light leakage.
2Manufacturing precision
If CMP or other methods are used to adjust the film thickness of the embedding film, then the film thickness can be controlled, but additional manufacturing steps are required, increasing manufacturing cost and reducing yield
Solution Approach 1:
The patent merges the embedding film formation process with the optical waveguide fabrication process. The photosensitive material serves dual purposes: as the embedding medium for the optical waveguide and as a thickness-control layer. The light exposure and development steps that define the optical waveguide pattern also control the embedding film thickness, eliminating the need for separate CMP or thickness adjustment steps.
Solution Approach 2:
The photosensitive material layer serves multiple functions simultaneously: it acts as the embedding medium for the optical waveguide, defines the optical waveguide pattern through photolithography, and controls the final embedding film thickness. This multi-functionality eliminates the need for separate processing steps dedicated solely to thickness control, thereby reducing manufacturing complexity and improving yield.
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 method allows for the adjustment of embedding film thickness in the pixel region without additional steps, reducing light leakage and improving manufacturing efficiency and yield by controlling the film thickness to a desired level.
Implementation Method 1
an exposure step of exposing a part of the photosensitive material to light; and a development step of removing the photosensitive material in the peripheral circuit region
Implementation Method 2
a hydrophilization step of hydrophilizing the photosensitive material between the application step and the development step
Implementation Method 3
a water-washing step of water-washing the photosensitive material between the hydrophilization step and the development step
Data Source
AI summary
The thickness of an embedding film in a pixel region is adjusted without adding a step.A method of manufacturing a solid-state image sensor (100) according to an embodiment of the present invention includes a development step of removing a photosensitive material (M) in a peripheral circuit region (30) and reducing and adjusting the thickness of the photosensitive material (M) that is in a pixel region (20) and on a multilayered wiring layer (5) to a desired film thickness.