Pressure Sensor Sagging Step Substrate Packaging

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Solution Overview

Problem

Existing pressure sensors face challenges in effectively transmitting human body-generated pressure to the sensing film while protecting the sensing film and wires from damage, and existing packaging methods are either overprotective, too large, or overly complex.

Innovation Solution

A pressure sensor design featuring a sagging step on the substrate with an insulation layer and strategically placed bonding pads connected by metal wires, where the wires are submerged below the sensing film to prevent damage and a soft material is used to transmit pressure without covering the sensing film, simplifying the packaging process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the sensing film is made thin to improve measurement sensitivity, then measurement precision is improved, but the sensing film becomes easily damaged by external physical pressure

Engineering Contradiction:

Improvemeasurement sensitivityVSAvoiddamage resistance

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The patent divides the packaging structure into distinct functional regions: a first region with the sensing film for pressure measurement, and a second region with protective structures for wire support. This segmentation allows the thin sensing film to maintain sensitivity while the separate protective region prevents damage to wires and other components.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements protective structures in advance before the sensing film and wires are exposed to external pressure. The package structure includes pre-designed support elements that cushion and protect the wires and bonding pads from mechanical damage before contact with external forces occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If wires are exposed above the sensing film to enable electrical connection, then ease of operation is improved, but the wires become easily damaged by direct contact

Engineering Contradiction:

Improveelectrical connectionVSAvoidwire damage from contact

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the package into a sensing region and a protective region. The wires are routed through the protective region which contains support structures, allowing electrical connections to be made while the wires remain protected from direct contact and mechanical damage.

Inventive Principle:

Principle #1Segmentation

3Reliability

If a prior package structure is used to protect the sensing film, then reliability is improved, but the structure becomes too large and overprotective

Engineering Contradiction:

Improveprotection of sensing filmVSAvoidpackage size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies protection locally rather than uniformly across the entire package. The protective structures are specifically positioned in the second region where wires and bonding pads are located, providing targeted protection without adding unnecessary volume to the overall package structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent combines multiple functions into a single integrated package structure: pressure sensing, wire protection, and electrical connection support are all achieved within one compact package design, eliminating the need for separate protective components that would increase size.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If a prior package structure is used to isolate the sensing film, then reliability is improved, but the structure becomes too large and pressure transmission becomes ineffective

Engineering Contradiction:

Improveisolation of sensing filmVSAvoidpressure transmission effectiveness

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the package into a first region for pressure sensing with direct film exposure, and a second region for protective functions. This segmentation ensures that pressure can be effectively transmitted to the sensing film in the first region while isolation and protection are provided in the separate second region.

Inventive Principle:

Principle #1Segmentation

5Reliability

If three kinds of materials are used in different regions for protection and pressure transmission, then reliability is improved, but the packaging process becomes too complicated

Engineering Contradiction:

Improveprotection and pressure transmissionVSAvoidpackaging process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs a packaging structure with multi-functional regions that perform multiple roles. The protective region provides both mechanical protection for wires and support for bonding pads, while the sensing region enables pressure transmission. This multi-functionality reduces the need for multiple specialized materials and simplifies the packaging process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20170036907A1Pressure Sensor and Packaging Method Thereof

Publication Date: 2017.02.09 MEMSENSING MICROSYST SUZHOU CHINA

AI summary

According to an embodiment of the present invention, a pressure sensor includes: a pressure sensing chip, which includes a substrate, a sensing film, an insulation layer and a first bonding pad; wherein the sensing film is on the substrate, and a sagging step is formed at one side of the substrate; the insulation layer is prepared on the sensing film and the substrate; the first bonding pad is prepared on the insulation layer on a bottom surface of the step, and is connected to the region of the substrate close to the sensing film via a lead wire.