What acid is most commonly used for IC decapsulation?

Fuming nitric acid (100% HNO₃) is the most widely used decapsulation acid for standard epoxy-molded IC packages — it selectively dissolves the epoxy molding compound while leaving gold wire bonds and aluminum die metallization intact. Fuming sulfuric acid or acid mixtures are used for more chemically resistant packages.

Can decapsulation damage the die or wire bonds?

Yes — over-exposure to acid can attack aluminum metallization, dissolve copper wire bonds or leadframes, and etch or stain the die surface. Careful process control (temperature, time, acid concentration) is critical to preserve evidence. Nitric acid does not attack gold wire bonds but will attack copper or aluminum wire bonds with prolonged exposure.

What is the difference between chemical and plasma (dry) decapsulation?

Chemical decapsulation uses liquid acid to dissolve the molding compound — fast, but can leave residues and attack sensitive metals with prolonged exposure. Plasma (dry) decapsulation uses reactive gas plasma to etch the polymer — slower but cleaner, with less risk of metal attack or corrosion product masking failure sites.

How is flip-chip package decapsulation different from wire-bond package decapsulation?

Flip-chip packages are opened from the back side (silicon substrate side) rather than the front — using mechanical grinding, laser ablation, or controlled chemical etching to thin the silicon and access the device layer. Front-side opening through underfill and solder bumps is also performed but requires more specialized techniques.

What can be found on a decapsulated die during failure analysis?

Typical findings include: ESD damage (metal splash, oxide damage at bond pads), corrosion of aluminum metallization, bond wire fracture or corrosion, die cracks, contamination particles on the die surface, assembly defects (mis-bonded wires, missing bonds), and passive layer damage from mechanical stress.

Dr. Bhargav Raval

Dr. Bhargav Raval is a Materials Scientist and Client Engagement Engineer with expertise in nanomaterials, polymers, and advanced material characterization. He holds a Ph.D. in Nanosciences from the Central University of Gujarat, where his research focused on graphene-based materials for flexible electronics. Professionally, he has led R&D in sensor technologies and coatings, including polymer-functionalized piezoelectric sensors for breath-based cancer diagnostics.
In his current role, Dr. Raval works closely with clients to understand technical requirements, design testing strategies, and deliver tailored solutions in materials selection, failure analysis, and performance evaluation. He effectively bridges scientific depth with practical outcomes, ensuring client-focused project execution. With peer-reviewed publications in high-impact journals and a proven record of applying materials science to real-world challenges, Dr. Raval continues to drive innovation at the intersection of research, engineering, and client engagement.

Email: bhargav@infinitalab.com

Website: https://scholar.google.com/citations?user=rlPTYWgAAAAJ&hl=en&oi=ao