Surface Analysis

EAG scientists are experts in surface analysis, encompassing various factors that influence surface chemistry and other surface-specific properties. When surface information is required, we will identify the most relevant analytical methods to deliver optimal results. Our laboratory employs diverse surface analysis and characterization techniques to investigate and address issues related to surface coverage, molecular orientation, functionalization, contamination, and surface segregation.

The chemical nature of a monolayer on a surface can significantly affect surface wettability, biocompatibility, reactivity, and adhesion. For example, plasma treatment and other gas-phase treatments are often used to modify the near-surface chemistry of polymer films prior to printing or bonding steps. Similarly, organosilanes and thiol-terminated self-assembled monolayers can be applied from solution to alter the surface chemistry of glass and metals.

EAG's Material Surface Analysis Laboratory addresses adhesion and bonding issues, questions regarding surface cleanliness, and investigations into material surface morphology and topography.

Adhesion and Bonding

Adhesion involves joining two or more surfaces together. Surface analysis studies may focus on adhesion and bonding problems. Failures can occur when contaminants are introduced during the process or when adhesive components are improperly formulated. Different material systems may exhibit various failure modes and root causes.

For polymer packaging, surface pretreatment, and organic coatings, failures may arise due to contaminants on or within the bonding surfaces. If adhesives are used, failures may also occur.
In cases of metal lead failures in microelectronics, the cause could be impurities, oxide layers, or buried substances diffusing onto the adhesion surface during or after bonding.

To uncover the root cause of adhesion and bonding issues in surface analysis laboratory studies, highly surface-sensitive analytical tools may be required. Whenever possible, both sides of a delaminated interface should be examined to investigate the failure site.

Cleanliness

Assessing surface cleanliness may involve a range of different measurement methods, depending on the surface and material of interest. It may also require comparing samples subjected to different treatments or exposed to varying environments. Differences between test samples and control or reference samples are often best highlighted through this approach. For example, highly sensitive measurements may reveal that cleaning chemicals leave residues because they were not properly rinsed away. Less sensitive techniques might not detect these residues or may lack sufficient signal to fully identify them.

Evaluating cleanliness typically requires understanding the potential sources of contamination:

• Is the contaminant an elemental or molecular species of interest?

• Is the presence or absence of a material confirmed?

• Are there specific concentration thresholds that the target species must remain below?

Studying extremely clean surfaces may require techniques with detection limits in the parts-per-million range, such as total reflection X-ray fluorescence (TXRF) for elemental species only, or time-of-flight secondary ion mass spectrometry (TOF-SIMS) for both elemental and molecular species. When cleanliness is measured by the number of particles on a surface, scanning electron microscopy (SEM) may be an excellent choice for surface imaging and particle counting.

Morphology and Topography

Morphology is a qualitative assessment of a surface's three-dimensional shape, while topography provides quantitative dimensional characteristics. The choice of surface characterization analysis technique depends on whether qualitative and/or quantitative information is needed.

Morphology, or "the appearance of a sample," is best evaluated using imaging techniques such as optical microscopy or scanning electron microscopy (SEM). These methods can also provide quantitative information such as layer thickness.

Topography, including roughness, step height, dimensions, and feature sizes, can be analyzed using atomic force microscopy (AFM), optical profilometry (OP), or stylus profilometry.

Contact our surface analysis laboratory experts immediately at +86 21 68796088 or fill out the form now!