Hybrid Sensor Chip Radiation-Shielding Wafer

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Solution Overview

Problem

Hybrid imaging sensor chip assemblies face issues with undesired radiative emission from CMOS ROICs, which can be absorbed by detectors, causing signal noise and potential damage from external radiation, particularly in low-background applications like astronomy.

Innovation Solution

A radiation-shielding wafer with through wafer vias is interposed between the CMOS ROIC and optical detector, physically and electrically coupled using wafer level bonding structures, to prevent radiative transfer while allowing electrical communication, using materials like copper and semiconductor absorbers to block or absorb unwanted radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a CMOS ROIC is used in a hybrid imaging sensor chip assembly, then the device can process and read out detector signals, but the CMOS ROIC generates radiative emission that is absorbed by the detector and creates signal noise

Engineering Contradiction:

Improvesignal processing capabilityVSAvoidradiative emission from CMOS ROIC

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

A radiation shielding layer is introduced as an intermediary component between the CMOS ROIC and the optical detector. This shielding layer blocks radiative emission from the CMOS ROIC while allowing electrical signals to pass through via through-wafer vias, thus eliminating the harmful effect without compromising the signal processing capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chip assembly is segmented into distinct functional layers: the optical detector layer, the radiation shielding layer, and the CMOS ROIC layer. This segmentation allows each layer to perform its specific function independently - the shielding layer blocks radiation while the through-wafer vias maintain electrical connectivity between the detector and ROIC

Inventive Principle:

Principle #1Segmentation

2Reliability

If light or high energy radiation passes through the detector to the ROIC, then the detector can collect the radiation, but the radiation impairs the functionality of the ROIC and may cause damage

Engineering Contradiction:

Improvedetector radiation detectionVSAvoidradiation damage to ROIC

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The radiation shielding layer serves as a protective intermediary that selectively blocks harmful radiation from reaching the CMOS ROIC while allowing the optical detector to continue collecting radiation signals. The through-wafer vias provide a protected pathway for electrical signals to traverse the shielding layer

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The radiation shielding layer, which necessarily blocks some radiation, is designed with through-wafer vias that allow the beneficial electrical signals to pass through while blocking the harmful radiative effects. The structure converts the potential harm of complete radiation blocking into the benefit of selective radiation filtering

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 effectively reduces undesired radiative emission and external radiation interference, enhancing the performance and reliability of hybrid imaging sensor chip assemblies in low-background applications by preventing radiative transfer between the CMOS ROIC and optical detector.

Implementation Method 1

The radiation-shielding wafer is configured to prevent radiative transfer from the CMOS ROIC to the optical detector, and/or from the optical detector to CMOS ROIC

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

a radiation-shielding layer (e.g., electromagnetic radiation-shielding layer) interposed between the detector and the CMOS ROIC

Methodology Applied

Scientific EffectElectromagnetic radiation shielding: Absorption (EM radiation)

Implementation Method 3

One or more through wafer vias (TWVs) within the radiation-shielding wafer enable electrical communication between the optical detector and CMOS ROIC

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS10418406B2Hybrid sensor chip assembly and method for reducing radiative transfer between a detector and read-out integrated circuit

Publication Date: 2019.09.17 RAYTHEON CO

AI summary

Aspects and examples described herein provide a hybrid imaging sensor chip assembly for reducing undesired radiative transfer between a complementary metal-oxide semiconductor (CMOS) read-out integrated circuit (ROIC) and an optical detector, and methods of manufacturing a hybrid imaging sensor chip assembly. In one example, a hybrid imaging sensor chip assembly includes an optical detector configured to collect electromagnetic radiation incident thereon, a complementary metal-oxide semiconductor (CMOS) read-out integrated circuit (ROIC), and a radiation-shielding wafer interposed between the optical detector and the CMOS ROIC, the radiation-shielding wafer including a plurality of through wafer vias (TWVs) electrically coupled to the optical detector and the CMOS ROIC, the radiation-shielding wafer being positioned to prevent radiative transfer between the CMOS ROIC and the optical detector.