Phase Corrector for Laser Trimming Integrated Circuit Components

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Solution Overview

Problem

Laser trimming of integrated circuit components is affected by interference patterns caused by reflections at material boundaries, leading to inconsistent heating and potential damage during the trimming process, especially with thicker trimmable components where previous phase shift techniques do not consistently work.

Innovation Solution

A phase corrector structure is integrated into the circuit, comprising correction regions of varying heights beneath and above the component to be trimmed, designed to introduce specific path length changes that minimize interference by aligning light reflections and ensuring uniform absorption of laser power, using step patterns that correspond to quarter wavelengths of the laser light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser trimming is performed on integrated circuit components, then component values can be adjusted to compensate for process variations, but interference patterns from material boundaries cause inconsistent heating and potential damage

Engineering Contradiction:
Improvecomponent value accuracyVSAvoidtrimming process reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent converts the harmful interference patterns caused by reflections at material boundaries into beneficial effects by introducing phase corrector structures that deliberately create controlled reflections. These controlled reflections are designed to cancel out the harmful interference patterns, transforming the problem of interference into a solution that uses interference constructively to achieve uniform heating during laser trimming

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The phase corrector structures act as intermediary elements between the laser beam and the component being trimmed. These structures include specific layer configurations (such as oxide layers with controlled thicknesses) that mediate the interaction between laser light and the component, controlling reflection and transmission to eliminate harmful interference patterns while allowing sufficient laser energy to reach the component for trimming

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If thicker trimmable components are used, then component functionality is improved, but previous phase shift techniques do not consistently work to eliminate interference patterns

Engineering Contradiction:
Improvecomponent thicknessVSAvoidtrimming uniformity
Core Design Contradiction:
Length of stationary objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by systematically varying the thicknesses of phase corrector layers (such as oxide layers) to optimize their optical properties. By adjusting these layer thicknesses to specific values (such as quarter-wavelength multiples), the structure transforms the interference pattern from harmful to beneficial, enabling consistent trimming performance across components of varying thicknesses

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent addresses the thickness problem by introducing additional dimensional complexity through multi-layer phase corrector structures. Rather than relying on simple single-layer phase shifters that fail for thick components, the invention uses multiple layers with different optical properties and thicknesses, adding dimensional complexity to the structure to achieve the desired optical interference control

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 achieves more uniform heating and improved accuracy in the trimming process, reducing variations in laser energy delivery and enhancing the reliability of the trimming operation, even with thicker components, by optimizing the absorption of laser power across the component.

Implementation Method 1

Boundaries between different layers of material within an integrated circuit can give rise to reflections within the integrated circuit being trimmed. These reflections can interfere, both constructively and destructively with the light from the trimming laser.

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

Boundaries between different layers of material within an integrated circuit can give rise to reflections within the integrated circuit being trimmed.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

ensuring uniform absorption of laser power, using step patterns that correspond to quarter wavelengths of the laser light

Methodology Applied
Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentEP2884502B1Integrated circuit with phase corrector for laser trimming a component
Publication Date: 2018.04.25 ANALOG DEVICES GLOBAL UNLTD
  • EP2884502B1 patent drawingFigure 1
  • EP2884502B1 patent drawingFigure 2
  • EP2884502B1 patent drawingFigure 3~4

AI summary

A phase corrector for laser trimming a component, the phase corrector comprising: a first correction structure located to a first side of the component, the first correction structure comprising first and second correction regions at first and second distances from the component; and a second correction structure located to a second side the component, the second correction structure comprising third and fourth correction regions at third and fourth distances from the component.