Pressure Sensor Packaging Using Gel and Lid

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Solution Overview

Problem

Pressure sensor dies are susceptible to mechanical damage during handling and packaging, and existing packaging methods using pre-molded lead frames are costly and do not allow full encapsulation, necessitating a metal lid for protection.

Innovation Solution

A method involving a lead frame with die pads and lead fingers, where a pressure sensor die and a second die are attached and electrically connected, covered with an encapsulating material and a gel, and then sealed with a lid, eliminating the need for pre-molded lead frames and reducing environmental exposure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pre-molded lead frames are used to package pressure sensor dies, then the dies are protected from mechanical damage during handling, but the packaging costs increase and full encapsulation is impeded

Engineering Contradiction:

Improveprotection from mechanical damageVSAvoidpackaging costs

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive pre-molded lead frames with a cost-effective alternative consisting of a mold cavity and encapsulating material. The lead frame functionality is achieved through a simple mold cavity structure that can be easily fabricated, eliminating the need for costly pre-molded lead frames while maintaining the protective function during packaging operations.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If pre-molded lead frames are used to package pressure sensor dies, then the dies are protected from mechanical damage, but full encapsulation is impeded requiring an additional metal lid

Engineering Contradiction:

Improveprotection from mechanical damageVSAvoidpackaging structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the protective function and encapsulation function into a single integrated structure. The mold cavity serves both as the packaging container and as the encapsulating structure, eliminating the need for separate lead frames and metal lids. This consolidation reduces the overall packaging structure complexity while maintaining comprehensive protection and encapsulation.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If a metal lid is placed on a mold wall to protect dies, then environmental damage is reduced, but packaging costs increase

Engineering Contradiction:

Improveenvironmental damage protectionVSAvoidpackaging costs

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent uses composite packaging structures where the mold cavity is formed from mold material and the encapsulating material provides environmental protection. This composite approach replaces the need for additional metal lid components while achieving the same environmental protection function, thereby reducing overall packaging costs.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS8802474B1Pressure sensor and method of packaging same

Publication Date: 2014.08.12 CHIP PACKAGING TECH LLC

AI summary

A method of packaging a pressure sensor die includes providing a lead frame having a die pad and lead fingers that surround the die pad. A tape is attached to a first side of the lead frame. A pressure sensor die is attached to the die pad on a second side of the lead frame and bond pads of the die are connected to the lead fingers. An encapsulant is dispensed onto the second side of the lead frame and covers the lead fingers and the electrical connections thereto. A gel is dispensed onto a top surface of the die and covers the die bond pads and the electrical connections thereto. A lid is attached to the lead frame and covers the die and the gel, and sides of the lid penetrate the encapsulant.