Backside Imaging Sensor Electrode Bonding for Substrate Alignment

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Solution Overview

Problem

There is a need to improve the reliability of back-side illumination type solid-state imaging devices by enhancing the joining reliability between substrates in configurations where the substrates are bonded together.

Innovation Solution

The solution involves forming a first wiring layer on a sensor substrate and a second wiring layer on a circuit substrate, with electrodes on each layer to facilitate electrical contact and improve the connection between the substrates, specifically through the use of first and second electrodes that connect the floating diffusion and other circuit elements across the substrate interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If substrates are bonded together in back-side illumination type solid-state imaging device, then photoelectric conversion efficiency is improved, but joining reliability between substrates deteriorates

Engineering Contradiction:

Improvephotoelectric conversion efficiencyVSAvoidjoining reliability between substrates

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies preliminary action by forming protrusions on the bonding surface of the first substrate and corresponding recesses on the second substrate before bonding. This pre-structured configuration ensures proper alignment and enhances joining reliability from the outset, preventing displacement issues that would otherwise occur during the bonding process.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces protrusions and recesses as intermediary structural elements that facilitate reliable bonding between substrates. These features act as mechanical intermediaries that guide alignment and ensure stable electrical connections, thereby improving joining reliability without compromising photoelectric conversion efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If substrates are bonded together to form back-side illumination structure, then light receiving performance is improved, but positional displacement between substrates occurs

Engineering Contradiction:

Improvelight receiving performanceVSAvoidpositional displacement between substrates

Core Design Contradiction:

Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the first substrate and recesses on the second substrate before bonding. This advance preparation ensures that when the substrates are bonded, the protrusions fit into the recesses, automatically aligning the substrates and preventing positional displacement, thereby maintaining manufacturing precision while achieving improved light receiving performance.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of substrate displacement into a benefit by designing protrusions and recesses that not only prevent displacement but also enhance the bonding reliability. The mechanical interlocking feature transforms what could be a manufacturing challenge into a reliability enhancement, ensuring both precise alignment and stable electrical connections.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances the reliability of the solid-state imaging device by ensuring stable electrical connections and minimizing positional displacement issues, thereby improving the overall performance and reliability of the device.

Implementation Method 1

a photodiode that is formed on a light receiving surface of a first semiconductor substrate

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

A first electrode is formed on a surface of the first wiring layer, and a second electrode is formed on a surface of the second wiring layer. The first electrode is in electrical contact with the second electrode.

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12538592B2Solid-state imaging device and electronic apparatus

Publication Date: 2026.01.27 SONY GROUP CORP

AI summary

A solid-state imaging device and method of making a solid-state imaging device are described herein. By way of example, the solid-state imaging device includes a first wiring layer formed on a sensor substrate and a second wiring layer formed on a circuit substrate. The sensor substrate is coupled to the circuit substrate, the first wiring layer and the second wiring layer being positioned between the sensor substrate and the circuit substrate. A first electrode is formed on a surface of the first wiring layer, and a second electrode is formed on a surface of the second wiring layer. The first electrode is in electrical contact with the second electrode.