Integrating IC and MEMS Microphone on Single Substrate

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Solution Overview

Problem

Existing methods for integrating silicon condenser microphones and integrated circuits on a single substrate face challenges, particularly with high-temperature processing that can damage metal electrodes and result in contamination, and the need for low-temperature techniques to avoid these issues.

Innovation Solution

A method involving a substrate with distinct areas for IC and microphone fabrication, where the IC is fabricated using standard semiconductor processing, and the silicon condenser microphone is built using low-temperature techniques, including forming a conducting layer, insulation layer, and a back plate with ventilation holes, while maintaining the integrity of the IC and microphone components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature processing is used to fabricate MEMS components on a substrate, then the MEMS component can be successfully manufactured, but the metal electrodes of the IC are damaged and contamination occurs

Engineering Contradiction:

ImproveMEMS component manufacturing successVSAvoidIC metal electrode damage and contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The substrate is divided into a first area for IC fabrication and a second area for MEMS fabrication. This spatial segmentation allows different processing conditions to be applied to each area independently, enabling the MEMS area to undergo high-temperature processing while the IC area is protected from such conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An insulation layer is introduced as an intermediary structure between the IC and MEMS components. This insulation layer acts as a protective barrier that prevents direct contamination and damage to the IC metal electrodes during MEMS fabrication processes, while still allowing the MEMS component to be successfully manufactured.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If single substrate integration is used to fabricate IC and MEMS on the same substrate, then noise interference is reduced and integral performance is improved, but high-temperature processing damages the IC metal electrodes

Engineering Contradiction:

Improveintegral performance and noise resistanceVSAvoidIC metal electrode damage from high temperature

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The substrate surface is segmented into distinct first and second areas, where the first area accommodates the IC and the second area accommodates the MEMS component. This segmentation enables the preservation of single-substrate integration benefits while allowing independent process optimization for each component type.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insulation layer extending from the IC area to the MEMS area serves as a protective intermediary that prevents contamination and damage to IC metal electrodes during high-temperature MEMS processing, while maintaining the electrical and structural integrity needed for low-noise performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If standard semiconductor processing is used for IC fabrication followed by MEMS fabrication, then IC manufacturing is efficient, but subsequent high-temperature steps contaminate the IC

Engineering Contradiction:

ImproveIC fabrication efficiencyVSAvoidIC contamination from subsequent processing

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The insulation layer is formed to extend over the IC area before MEMS fabrication begins. This preliminary protective action ensures that when subsequent high-temperature MEMS processing steps are performed, the IC is already protected and cannot be contaminated, thus preserving both productivity and cleanliness.

Inventive Principle:

Principle #10Preliminary action

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 approach allows for the successful integration of IC and silicon condenser microphones on a single substrate without high-temperature processing, preventing contamination and ensuring the reliability of both components, enabling their use in high-temperature applications.

Implementation Method 1

the diaphragm is deformed under influence of the sound pressures of the sound signals, which changes the capacitance between the diaphragm and the back plate. As a result, the change of the capacitance is transformed into the electronic signals

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS8438710B2Method of manufacturing a structure with an integrated circuit and a silicon condenser microphone mounted on a single substrate

Publication Date: 2013.05.14 MEMSENSING MICROSYST SUZHOU CHINA

AI summary

A structure with an integrated circuit (IC) and a silicon condenser microphone mounted thereon includes a substrate having a first area and a second area. The IC is fabricated on the first area in order to form a conducting layer and an insulation layer. Both the conducting layer and the insulation layer further extend to the second area. The insulation layer is removed under low temperature in order to expose the conducting layer on which the silicon condenser microphone is fabricated. The silicon condenser microphone includes a first film layer, a connecting layer and a second film layer under a condition that the connecting layer connects the first and the second film layers. The first film layer and the second film layer act as two electrodes of a variable capacitance.