Overview
ISO 16525-9:2014 defines standardized test methods for determining high-speed signal‑transmission characteristics of isotropic electrically conductive adhesives (ICA). It covers measurements in bonded regions where an ICA joins surface‑mounted device (SMD) terminals to printed circuit board (PCB) land patterns, and for ICA‑printed wiring on PCBs. The standard focuses on extracting the adhesive’s contribution to signal integrity (eye pattern, scattering parameters, TDR, impedance) while minimising the unavoidable influence of surrounding copper traces.
Key topics and technical requirements
- Two evaluation approaches:
- Measure high‑speed transmission of a printed wiring pattern formed with ICA.
- Measure bonded joints where SMD terminals are attached with ICA, using lead‑free solder as a reference.
- Signal integrity metrics:
- Eye pattern analysis for digital random pulses (characteristics of high‑speed signal transmission).
- Scattering parameters (S11, S21) measured with a network analyser to quantify frequency response.
- Time‑domain reflectometry (TDR) for characteristic impedance profiling and reflection analysis.
- Recommended apparatus and ranges:
- Random pulse generator (≈0.05–12 Gbps) and oscilloscope (up to 18 GHz).
- SMA coaxial connectors rated to ~20 GHz; network analyser typically 50 MHz–40 GHz (measurement commonly 100 MHz–30 GHz).
- TDR oscilloscope with step rise time ≲30 ps.
- Test board and sample design:
- FR‑4 (glass‑fabric epoxy) substrates and defined PCB patterns to match 50 Ω test equipment and minimise copper line influence.
- Procedures for subtracting the copper‑only baseline to isolate ICA behavior.
- Documentation: Procedures for board preparation, apparatus setup, pass/fail judgement and reporting are specified, plus normative annexes with sample structures, implementation examples and application methods.
Applications
- Quantifying the high‑frequency performance of ICAs used for:
- BGA and other SMD interconnections where solder is impractical.
- Printed conductive traces formed from adhesive on PCB substrates.
- Assessing whether an ICA is suitable for high‑speed digital interfaces in consumer electronics, telecommunications, automotive or industrial electronics.
- Comparative testing of adhesive formulations for signal integrity and design validation of ICA‑based interconnects.
Who should use this standard
- Adhesive manufacturers and R&D teams developing conductive adhesives.
- Test laboratories and quality assurance teams performing signal‑integrity qualification.
- PCB designers, SMT/process engineers and reliability engineers evaluating alternatives to solder for high‑speed applications.
Related standards
Normative references include ISO 472 and IEC standards such as IEC 60194, IEC 61190‑1‑2, IEC 61192‑1, IEC 61249‑2‑7/‑2‑8 and IEC 61760‑1. These provide complementary definitions, materials and assembly requirements relevant to ICA testing.
Open preview (PDF)Adhesives — Test methods for isotropic electrically conductive adhesives — Part 9: Determination of high-speed signal-transmission characteristics
