Image Sensor Substrate Isolation Using Lens Material Pad Masking
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Solution Overview
Problem
Current image sensing devices face inefficiencies in production due to the complexity of forming trench isolation structures and direct pads, requiring multiple masks and fabrication processes.
Innovation Solution
The implementation of a new substrate isolation structure and fabrication process that includes a lens material-based substrate isolation layer, allowing for the simultaneous formation of substrate isolation trenches and pad holes using a single etching mask, thereby reducing the number of masks and processes needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to form substrate isolation structures and direct pads, then the structures can be formed with existing processes, but the number of masks and fabrication processes increases, reducing production efficiency
Solution Approach 1:
The patent combines the formation of substrate isolation structures and direct pads into a single integrated process. The lens material layer serves dual purposes: it forms the substrate isolation layer when deposited in peripheral regions, and simultaneously serves as an etching mask to expose electrode pads when deposited over pad holes. This merging of functions reduces the total number of fabrication steps and masks required.
Solution Approach 2:
The lens material layer performs multiple functions within the fabrication process. It acts as both a structural material for substrate isolation and as a protective mask during pad exposure etching. This multi-functionality eliminates the need for separate mask layers and reduces process complexity, directly addressing the contradiction between ease of manufacture and production efficiency.
2Manufacturing precision
If multiple masks and fabrication processes are used to form substrate isolation structures and direct pads, then precise structure formation is achieved, but the manufacturing complexity and process time increase
Solution Approach 1:
The patent merges multiple fabrication operations into a single lens material deposition step. By depositing the lens material layer across the entire substrate simultaneously, the process achieves precise formation of both substrate isolation structures and pad exposure masks in one operation, reducing manufacturing complexity while maintaining precision.
Solution Approach 2:
The lens material layer is deposited in advance before the etching process, serving as a pre-formed mask that defines the pad exposure regions. This preliminary action ensures precise pad exposure while simplifying the overall process sequence, as the mask is already in place when etching begins.
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 approach enhances production efficiency by simplifying the fabrication process and reducing the complexity of forming trench isolation structures and direct pads in image sensing devices.
Implementation Method 1
forming a lens material layer over the first substrate such that a lens material is formed at a sidewall of the pad hole while filling the substrate isolation layer trench
Implementation Method 2
exposing an electrode pad disposed in the second insulation layer by etching the first insulation layer and the second insulation layer using the lens material layer formed at the sidewall of the pad hole as an etching mask
Data Source
AI summary
An image sensing device includes a first substrate including a first surface and a second surface facing away from the first surface, the first substrate including a pixel region and a pad region located outside the pixel region, the pixel region being structured to include pixel that generate electrical signals based on light incident upon the first surface to reach to the pixels, an insulation layer disposed under the second surface and including interconnects and an electrode pad, a pad open region disposed in the pad region and structured to expose the electrode pad, and a substrate isolation layer disposed outside the pixel region in the first substrate and formed to penetrate the first substrate. The substrate isolation layer includes a lens material.