Solid-State Image Sensor Wiring Layout for Uniform Light Reflection
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Solution Overview
Problem
The existing structure for bonding a separate chip to the circuit surface of an imaging element chip leads to variations in light reflection, resulting in nonuniform reflection of incident light.
Innovation Solution
A solid-state imaging apparatus is designed with an imaging element chip and a device chip bonded to a wiring layer opposite the light incident surface, where the wiring layer includes dummy metal wiring in regions not occupied by the device chip, ensuring uniform light reflection by matching the plane size and pitch of metal wirings and dummy vias within the pixel region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a device chip is bonded to the pixel region of the imaging element chip, then high functionality of the imaging element is achieved, but nonuniform reflection of incident light occurs
Solution Approach 1:
The patent applies local quality by making different regions of the wiring layer have different structures: regions with device chips contain metal wirings for electrical connection, while regions without device chips contain dummy metal wirings. This local differentiation ensures that both regions reflect light uniformly, solving the nonuniform reflection problem while maintaining the functionality benefits of device chip bonding.
Solution Approach 2:
The patent uses dummy metal wirings as copies of the actual metal wirings. These dummy wirings replicate the structure, material, and optical properties of the functional metal wirings but are placed in regions where no device chip is bonded. This copying approach creates uniform light reflection across the entire pixel region without interfering with the electrical functionality of the actual connections.
2Reliability
If metal wirings are formed only in regions where device chips are disposed, then electrical connection is achieved, but light reflection becomes nonuniform
Solution Approach 1:
The wiring layer is designed with local quality differentiation: functional metal wirings in device chip regions for electrical connection, and dummy metal wirings in non-device chip regions for optical uniformity. Each region has the appropriate structure for its specific function, resolving the contradiction between electrical connection reliability and light reflection uniformity.
Solution Approach 2:
The dummy metal wirings serve a dual purpose: they maintain the structural uniformity of the wiring layer for optical reasons, and they provide a template for potential future electrical connections. This multi-functionality allows the same wiring layer structure to serve both electrical and optical requirements.
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 effectively suppresses nonuniform light reflection, resulting in high-quality imaging signals by ensuring equal reflection across the pixel region.
Implementation Method 1
suppress nonuniform reflection of incident light
Data Source
AI summary
The present disclosure relates to a solid-state imaging apparatus, a manufacturing method thereof, and electronic equipment that are able to suppress nonuniform reflection of incident light. The solid-state imaging apparatus includes an imaging element chip and a device chip. The imaging element chip has a semiconductor substrate. The device chip is bonded to a wiring layer opposite the light incident surface of the semiconductor substrate. The device chip is disposed in a pixel region of the imaging element chip. The wiring layer of the imaging element chip includes a dummy metal wiring in a region where the device chip of the pixel region is not disposed. The technology according to the present disclosure is applicable, for example, to the solid-state imaging apparatus that is formed by bonding the imaging element chip to the device chip.