Printhead Die Damage Detection Conductor Rings

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Solution Overview

Problem

Printhead dies in inkjet printheads are prone to damage from kerf chipping during the sawing process, leading to reduced yields and increased costs due to electrical failures caused by corrosive ink exposure, as existing detection methods are inadequate and time-consuming.

Innovation Solution

The implementation of concentric termination rings with damage detection conductors nestled between them, utilizing a grown SiO2 layer and berms to prevent kerf chip propagation and provide graduated damage data, along with a processor-readable medium to assess damage levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional edge termination structures are used, then the device complexity is low, but the reliability is poor due to kerf chip damage and corrosive ink exposure

Engineering Contradiction:

Improveprinthead die reliabilityVSAvoidedge termination structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The edge termination structure is segmented into multiple concentric rings (first termination ring, second termination ring, third termination ring) with berms between them. This segmentation allows the structure to detect and respond to damage at different levels, preventing corrosive ink from reaching functional areas even when outer rings are compromised.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The damage detection conductors are pre-positioned between the termination rings before operation. When kerf chip damage occurs, the system can immediately detect it through resistance changes in these conductors, allowing preliminary action to be taken before corrosive ink causes electrical failure.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If multiple concentric termination rings with detection conductors are implemented, then the reliability improves through damage detection, but the device complexity increases

Engineering Contradiction:

Improvedamage detection capabilityVSAvoidtermination ring and conductor structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The termination rings serve multiple functions: they provide electrical termination, mechanical support, and damage detection. The berms between rings serve dual purposes as structural elements and as pathways for damage detection conductors. This multi-functionality reduces the need for separate dedicated detection structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The damage detection conductors act as intermediaries between the physical damage (kerf chips) and the detection system. These conductors are positioned to be affected by damage in specific zones, translating physical damage into measurable electrical resistance changes that can be monitored.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the edge termination structure is enhanced with multiple rings and berms, then the resistance to corrosive ink improves, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveprotection against corrosive inkVSAvoidconcentric ring alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The concentric termination rings provide progressive protection zones. If outer rings are damaged during manufacturing or operation, the inner rings serve as backup protection. The berms create physical barriers that cushion against kerf chip propagation, allowing for some manufacturing variation while maintaining protection.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Measurement precision

If damage detection conductors are placed between termination rings, then the detection precision improves, but the device complexity increases

Engineering Contradiction:

Improvedamage detection precisionVSAvoidconductor network complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The damage detection conductors are positioned in specific locations between termination rings where they are most effective at detecting damage. Each conductor monitors a specific zone, providing localized detection capability. This targeted positioning optimizes detection precision without requiring a dense network of conductors throughout the entire structure.

Inventive Principle:

Principle #3Local quality

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 solution effectively detects and mitigates kerf chip damage, reducing the risk of electrical failures and increasing the reliability of printhead dies by providing a robust edge termination system that prevents corrosive ink exposure and allows for early detection of defects.

Implementation Method 1

A damage detection conductor is formed under the berm and on top of the SiO2 layer

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS20140320566A1Printhead Die With Damage Detection Conductor Between Multiple Termination Rings

Publication Date: 2014.10.30 HEWLETT PACKARD DEVELOPMENT COMPANY LP

AI summary

In one example implementation, a printhead die includes a SiO2 layer grown into a surface of a silicon substrate, a dielectric layer formed on the surface over an interior area of the substrate, a first termination ring surrounding the interior area and defined by an absence of the dielectric layer, a berm surrounding the first termination ring and defined by the presence of the dielectric layer, a damage detection conductor formed under the berm on the SiO2 layer, and a second termination ring surrounding the berm and defined by an absence of the dielectric layer.