Technical Insight
Adhesion, Die Shear, Peel, Cross-Section, and Fractography for Interconnect Qualification
Match the mechanical method to the package load path and use cross-sections and complete failure-surface allocation to determine whether a result represents joint cohesion, one interface, metallization, substrate, fixture, or mixed failure.
Author: Aurexene Materials Engineering Team · Last updated: 2026-08-28
Quick Answer
Match the mechanical test to the package load path, keep geometry, fixture, alignment, rate, direction, temperature and aging attached to the full load-displacement record, then locate the complete failure path with planned cross-sections and paired fracture surfaces. Separate cohesive joint, paste-to-finish, within-metallization, metallization-to-substrate, substrate and mixed failure. Peak load is not an interface, and shear and peel are not directly interchangeable.
Problem
Different test modes load different parts of a joint. Peak values change with area, thickness, edges, tool position, compliance, rate, temperature and time-dependent response, while the strongest measured specimen may have failed outside the intended interface.
Mechanism
Load transfers through joint microstructure, both interfaces, metallization layers, substrate, fixture and package. Pores, cracks, necks, surface preparation, reaction layers, residual stress and aging determine initiation and propagation.
Cross-sections sample selected planes and can add artifacts. Fractography reveals broader paths but needs both mating surfaces, scale, orientation, chemistry where necessary, and full area allocation. Electrical and mechanical damage must be correlated rather than assumed.
Tradeoff
A simple shear screen supports throughput but provides limited mode and path resolution. More representative modes and environments improve relevance while adding variation and cost. Area normalization helps only when bond area and load distribution are valid.
Material Strategy
Compare Nano Ag Powder, Nano Cu Powder, Nano Ni Powder, and Nano Sn Powder on matched joints and failure allocation. Evaluate Graphene Copper (Graphene-Cu) or SWCNT-nano-Ag only with phase location, matched metal controls, and registered crack evidence.
Recommended Architectures
| Route | Use when | Reject boundary | Proof |
|---|---|---|---|
| Production screen | Stable geometry and known failure mode support monitoring | Fixture or failure path shifts outside the qualified correlation | Capability, load-displacement, geometry, sampled surfaces, qualification correlation |
| Load-path qualification | Application shear peel tension or another mode must be represented | Peak values are compared across unmatched modes or geometries | Mode and fixture, area and thickness, aging, sections, failure allocation, uncertainty |
| Hybrid crack-path study | A carbon phase is proposed to alter crack or contact retention | Fracture-surface carbon is treated as bridging proof | Phase location, paired surfaces, registered sequence, matched control, resistance, cycling |
Measurement & Validation
- Define the application load path, allowable failure modes, full joint and metallization stack, geometry, environment, aging, electrical correlation, and acceptance decision.
- Record fixture, tool contact and height, alignment, compliance, mode, direction, rate, dwell, temperature, conditioning and complete load-displacement; report raw load before derived stress or energy.
- Metrologize bond area and thickness and validate any uniform-stress or normalization assumption.
- Cross-section a planned set of centers, edges, corners and defects with smear, pullout and preparation-artifact controls.
- Examine both mating fracture surfaces and allocate cohesive, each interface, metallization-layer, substrate and mixed failure area; confirm aged controls, production lots, censoring and uncertainty.
Qualification Boundary
Freeze load path, joint and metallization stack, geometry area and thickness, material and paste lots, formulation process and surface history, initial resistance and defects, specimen selection, fixture tool alignment compliance and calibration, mode direction rate dwell temperature environment and recovery, cross-section sampling and preparation, paired fractography and chemistry, failure allocation, aging, production lots, repeats, censoring, uncertainty, and acceptance criteria.
Related Products
Related Applications
Related Comparisons
Downloads & Engineering Support
Both resources remain approval-required and cannot establish adhesion, strength, interface, joint, or reliability performance.
- Request an interconnect mechanical review
- Discuss mechanical, cross-section, and fractographic analysis
- Discuss production screening and sampling
What to Validate
The qualification framework is engineering guidance. Confirm adhesion, strength, crack, interface, production, or life performance until verified grade-, joint-, geometry-, fixture-, load-, interface-, imaging-, method-, and application-specific evidence is available.
Need to apply this boundary to a grade, formulation, test method, or production route? Discuss it with the Aurexene Materials Engineering Team.