Moisture-Impermeable Dielectric Passivation Layer for Circuit Devices

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Solution Overview

Problem

Conventional passivation techniques for circuit devices using silicon-nitride or silicon-carbide materials provide inadequate moisture protection, leading to moderate passivation and performance degradation due to thickness requirements and susceptibility to moisture, which increases internode capacitance and induces cracking or delamination.

Innovation Solution

A system employing thinner, moisture-impermeable dielectric layers such as alumina, silicon-dioxide, or parylene-based materials with superior voltage breakdown characteristics, applied in multiple layers to provide precise control and protection without compromising circuit performance, including the use of atomic layer deposition for conformality and reduced stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional passivation techniques using silicon-nitride or silicon-carbide are employed, then moisture protection is provided, but thickness requirements increase leading to increased internode capacitance and performance degradation

Engineering Contradiction:
Improvemoisture protectionVSAvoidpassivation layer thickness
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent changes the material parameters by transitioning from conventional silicon-nitride/silicon-carbide to alumina and parylene-based materials. This material substitution enables achieving the same moisture protection level with significantly reduced thickness, thereby resolving the contradiction between reliability and layer thickness.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite passivation structures combining multiple dielectric layers (alumina, silicon-dioxide, parylene) with different properties. This composite approach allows optimization of both protective function and electrical performance by leveraging the complementary characteristics of each material.

Inventive Principle:
Principle #40Composite materials

2Reliability

If thicker passivation layers are used to improve moisture protection, then reliability improves, but internode capacitance increases causing performance degradation

Engineering Contradiction:
Improvepassivation effectivenessVSAvoidinternode capacitance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

By changing the dielectric material parameters (using materials with lower permittivity and superior moisture barrier properties), the patent achieves high passivation effectiveness without increasing layer thickness, thus avoiding the generation of harmful capacitive effects.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If hermetic packaging is used to protect circuit devices, then protection against contaminants is improved, but device complexity and packaging density are reduced

Engineering Contradiction:
Improvecontaminant protectionVSAvoidpackaging structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent extracts the protection function from the packaging structure and transfers it to the passivation layer itself. By providing superior contaminant protection at the device level through advanced dielectric materials, the need for complex hermetic packaging is eliminated or reduced.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of manufacture

If conventional dielectric materials are used, then manufacturing is simplified, but conformality over three dimensional features and thickness uniformity are compromised

Engineering Contradiction:
Improvedielectric applicationVSAvoidthickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces conventional mechanical/sputtering deposition methods with atomic layer deposition (ALD) technology. This substitution enables precise control of thickness and superior conformality over three-dimensional features while maintaining manufacturing feasibility through a well-established deposition process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 achieves superior electrical performance and enhanced protection against moisture and contaminants, eliminating the need for hermetic packaging while maintaining thin layer thickness to avoid performance degradation, thus improving reliability and packaging density.

Implementation Method 1

The dielectric material is atomic layer deposited on the substrate and the electrical components

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Implementation Method 2

moisture-impermeable dielectric layers such as alumina, silicon-dioxide, or parylene-based materials

Methodology Applied
Scientific EffectPermeation barrier: Permeation

Data Source

PatentEP2385546B1Passivation layer for a circuit device and method of manufacture
Publication Date: 2014.07.16 RAYTHEON CO
  • EP2385546B1 patent drawingFigure 1
  • EP2385546B1 patent drawingFigure 2
  • EP2385546B1 patent drawingFigure 3

AI summary

According to one embodiment of the disclosure, a method for passivating a circuit device generally includes providing a substrate having a substrate surface, forming an electrical component on the substrate surface, and coating the substrate surface and the electrical component with a first protective dielectric layer. The first protective dielectric layer is made of a generally moisture insoluble material having a moisture permeability less than 0.01 gram/meter2/day, a moisture absorption less than 0.04 percent, a dielectric constant less than 10, a dielectric loss less than 0.005, a breakdown voltage strength greater than 8 million volts/centimeter, a sheet resistivity greater than 1015 ohm- centimeter, and a defect density less than 0.5/centimeter2. To be accompanied, when published, by Figure 1 of the accompanying drawings.