CMOS Pressure-Strain Sensor Layout With Dielectric Strain Transfer

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Solution Overview

Problem

Conventional mechanisms for sensing external pressure/strain in advanced CMOS process nodes are either expensive, not well integrated, or have poor sensitivity, and they either create electrostatic discharge paths or involve costly packaging.

Innovation Solution

A pressure/strain sensor design in a CMOS process that includes a substrate with a contact field plate, a dielectric layer, and a pressure/strain terminal, utilizing a mechanical path for efficient strain transfer without affecting other circuit elements, using piezo resistance, bipolar junction transistors, diodes, or MOSFETs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional pressure/strain sensing mechanisms are used, then sensing capability is provided, but they are expensive, not well integrated with CMOS process, or have poor sensitivity

Engineering Contradiction:

ImprovesensitivityVSAvoidintegration with CMOS process

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the pressure/strain sensing function with standard CMOS process elements by using existing field plates and dielectric layers as sensing structures. The contact field plate and associated dielectric layer, which are standard components in CMOS power devices, are repurposed to serve dual functions: electrical field control and mechanical strain sensing, eliminating the need for separate sensing mechanisms and achieving full CMOS integration

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent makes standard CMOS components universal by enabling the contact field plate and dielectric layer to perform multiple functions simultaneously. These structures serve both their traditional electrical function in power device operation and a new mechanical sensing function, allowing the same hardware to provide both device operation and pressure/strain detection without additional components

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If conventional pressure/strain sensing mechanisms are used, then sensing capability is provided, but they create electrostatic discharge paths

Engineering Contradiction:

Improvesensing capabilityVSAvoidelectrostatic discharge

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the dielectric layer as an intermediary between the contact field plate and the underlying device structures. This dielectric intermediary allows mechanical strain to be transmitted to the sensing element while electrically isolating the field plate, preventing electrostatic discharge paths from forming through the sensing structure while still enabling effective strain transfer for sensing

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If conventional pressure/strain sensing mechanisms are used, then sensing capability is provided, but they involve costly packaging

Engineering Contradiction:

Improvesensing capabilityVSAvoidpackaging cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines the sensing function with the existing CMOS device structure and packaging framework. By using standard CMOS process elements (field plates, dielectric layers) that are already present in the device, the sensing function is integrated into the existing manufacturing and packaging flow, eliminating the need for separate sensing component packaging and reducing overall packaging costs

Inventive Principle:

Principle #5Merging (Combining)

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

The design efficiently transfers external pressure/strain to a sensing element, enhancing sensitivity and avoiding electrostatic discharge, while being cost-effective and well-integrated with the CMOS process.

Implementation Method 1

The IC structure includes a dielectric layer between the first contact field plate and the active/passive device to provide a direct pressure/strain contact

Methodology Applied

Scientific EffectMechanical strain transfer: Mechanical Force

Implementation Method 2

using piezo resistance, bipolar junction transistors, diodes, or MOSFETs

Methodology Applied

Scientific EffectPiezo resistance: Piezoresistive Effect

Data Source

PatentUS20250207987A1Pressure/strain sensor design in a complementary metal oxide semiconductor (CMOS) process

Publication Date: 2025.06.26 QUALCOMM INC

AI summary

An integrated circuit (IC) structure is described, including a substrate and a device on the substrate. The IC structure also includes a first contact field plate above the device. The IC structure further includes a dielectric layer between the first contact field plate and the device. The IC structure also includes a pressure/strain terminal coupled to the first contact field plate.