Capacitive Biasing for pH Detection Area Integrity

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Solution Overview

Problem

Existing lab-on-a-chip devices face challenges in maintaining a non-floating potential at the input interface of the detection module, which can lead to reduced detection accuracy and contamination of the insulating region during the manufacturing process, thereby decreasing the detection area.

Innovation Solution

An integrated detection device is designed with a biasing stage that uses capacitive coupling to bias the electrically conductive region, eliminating the need for additional processing steps above the insulating region and maintaining the integrity of the insulating material, allowing for a larger detection area and improved sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrode is produced on the insulating region to bias the contact pad, then the input interface potential is fixed, but the insulating region is exposed to etching steps which damages or contaminates the insulating material and decreases the detection area

Engineering Contradiction:

Improveinput interface potential stabilityVSAvoiddetection area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent moves the biasing electrode from the vertical dimension (on top of the insulating region) to the horizontal dimension (in the same metallization level as the contact pad, separated by insulating material). This dimensional relocation allows biasing functionality without occupying detection area or exposing the insulating region to etching damage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces an intermediary insulating material layer between the biasing electrode and the detection insulating region. This intermediary structure allows capacitive coupling for biasing while physically protecting the detection area from etching exposure and contamination.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If an electrode is produced on the insulating region to bias the contact pad, then the input interface potential is fixed, but the production process becomes more complex with additional etching steps

Engineering Contradiction:

Improveinput interface potential stabilityVSAvoidproduction process simplicity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the biasing electrode production with the existing metallization process. The biasing electrode is formed in the same metallization level as the contact pad, using the same deposition and patterning steps, thereby eliminating additional etching processes while maintaining reliable potential fixation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The insulating material layer serves multiple functions: it acts as a separator between the biasing electrode and contact pad, provides capacitive coupling for biasing, and protects the detection insulating region from etching damage. This multi-functionality simplifies the overall manufacturing process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enhances the sensitivity of the detection device by up to three times compared to prior art, while avoiding contamination and maintaining a larger detection area, thus improving the accuracy and efficiency of molecular detection.

Implementation Method 1

a biasing stage configured to bias said electrically conductive region by capacitive coupling

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

configured to detect a variation in potential on said interface in the presence of said element on the insulating region

Methodology Applied

Scientific EffectPotential variation detection: Electric Field

Data Source

PatentUS10794856B2Detection device, in particular incorporated in a PH meter, and corresponding production process

Publication Date: 2020.10.06 STMICROELECTRONICS (CROLLES 2) SAS

AI summary

A detection stage of an electronic detection device, for example a pH meter, includes an insulating region that receives an element to be analyzed. The insulating region is positioned on a sensing conductive region. A biasing stage includes an electrically conductive region which is capacitively coupled to the conductive region. The electrically conductive region is formed in an uppermost metallization level along with a further conductive region. That further conductive region is electrically connected to the sensing conductive region by a via passing through an insulating layer which insulates the electrically conductive region from the sensing conductive region.