Peel Test of Plating Film on Resin Under Varied Temperature Environments

Significance of the Topic

Plating on resin substrates is widely used in automotive, electronics and semiconductor industries for decorative, functional and electrical applications. Reliable adhesion under extreme temperature conditions is critical for component performance and longevity. Conventional thermal cycle or heat shock tests lack quantitative precision, motivating the development of a standardized peel test to assess adhesion across a broad temperature range.

Objectives and Study Overview

This study aimed to quantify the adhesion strength of copper films on a hard-to-plate resin (PBT) substrate over temperatures from -50 °C to 125 °C. Two seed layer deposition methods—physical sputtering and chemical electroless plating—were compared to evaluate how seed layer technique influences adhesion behavior.

Methodology

Specimens measured 30 mm × 100 mm × 2 mm and featured a central 10 mm wide scribed peel area. A copper plating thickness target was 25 μm, with measured values spanning 15–30 μm. Peel tests were conducted at 25 mm/min, with valid force data recorded from 10 mm to 60 mm of peel length. Five replicate tests were performed at eight set temperatures: -50 °C, -25 °C, 0 °C, 25 °C, 50 °C, 75 °C, 100 °C and 125 °C.

Used Instrumentation

• Universal testing machine: AGX-50NV2D (Shimadzu)
• Load cell capacity: 50 N
• Peel jig: copper foil peel test device
• Thermostatic chamber: air-cooled refrigerator chamber TCR2A
• Data acquisition software: TRAPEZIUM X-V

Results and Discussion

Preliminary room-temperature tests showed a strong correlation (R = 0.86) between film thickness and adhesion force. In temperature-varying tests (20–25 μm films), sputtered seed layers exhibited a gradual decrease in adhesion from 12.33 N at -50 °C to 8.99 N at 125 °C (–11.7 % relative to 25 °C). Electroless seed layers maintained stable adhesion up to 75 °C, then dropped sharply to 2.39 N at 125 °C (–30.5 %). These trends indicate that seed layer deposition method and operating temperature critically influence peel strength.

Benefits and Practical Applications

• Provides a quantitative measure of plating adhesion under realistically varied temperature environments.
• Supports development and optimization of resin materials, plating seed processes and electroplating chemistries.
• Enables quality control in manufacturing of automotive and electronic components exposed to extreme thermal conditions.

Future Trends and Potential Applications

Integration of high-throughput peel testing, advanced in situ monitoring and predictive modeling of adhesion behavior could accelerate material development. Exploring novel seed layer chemistries and nanostructured interfaces may further enhance thermal stability of plating films. Adapting this method to other resin–metal systems will broaden application scope in aerospace, energy and biomedical devices.

Conclusion

The precision universal peel test effectively quantifies adhesion of copper films on PBT substrates across a wide temperature range. Results highlight the impact of seed layer deposition technique on thermal adhesion performance. This approach offers a robust, quantitative tool for research, development and quality assurance in plating technologies.