DECAPSULATION

MECHANICAL DECAPSULATION

Precision Milling and Grinding methods provide the most accurate means of removing electronic packaging materials with the highest circuit survivability. ULTRA TEC provides a range of mechanical decapsulation systems for all budgets.

PRE-CAVITATION

The initial removal of bulk material from the package is typically known as pre-cavitation.

Depending on the package type, chemical decapsulation may work well for the entire decapsulation. However, survivability and straighter, better defined etch walls are achievable with mechanical methods. The process must be stopped at a finite distance above the die to maintain electrical integrity.  ASAP-1 products are market-tested for pre-cavitation down to a few microns of remaining encapsulant.

It is not possible to uncover the bond wires using a single process. Use of Tunnel Decap can mitigate this and make the bond wires more easily obtainable.  

END-POINT METHODS

Creating access points in IC's has traditionally required iterative guesswork to reach target. Packaging non-uniformity is problematic both for chemical and laser decap techniques, but can be easily accommodated in mechanical decap. Use of electronic end-pointing techniques allow for repeatable thinning with a resolution of less than 1 micron, and remove the need for the engineer to 'stop and look' multiple times during the process. Previously-exposed areas can be masked to allow for a new, typically smaller, area to be exposed.

Recent advantages in software have taken electronic end-pointing to a new level of user-friendliness with the addition of closed-loop settable Trip-Points. Automatic Trip-Points may be set for position and pressure, in addition to capacitance.

It is also possible to decapsulate larger boards and modules. More details in the summary video below.

FINAL DECAPSULATION

Pre-cavitation can assist in the selection and ease of Final Decapsulation with plasma or chemical methods.

Manual acid decap methods (using eye-dropper and hot plate) provide a comprehensive means of fully decapsulating plastic-packaged components. However, to maintain functional circuitry after the removal of encapsulant materials it is often necessary to use decapsulation sequences and recipes that stay within temperature limits and do not corrode or oxidize bond wires.

MANY REASONS FOR CHIP ACCESS

The use of mechanical decapsulation equipment is crucial for Chip Off techniques in DIGITAL FORENSICS

QC and QA checks are also required to check for part integrity and anti-counterfeit requirements. Many methods exist to decapsulate the array of packages - no one size fits all!

Further Reading:

Frontside Sample Preparation - by Jim Colvin Microelectronics Failure Analysis Desk Reference, Seventh Edition, publ ASM Int’l 

‘In Situ’ Mechanical Sample Preparation of Selected Sites and Components on Large Modules and Boards – Colvin, Hazeldine & Patel (presented at ISTFA 2016)

FemtoFarad/TeraOhm Endpoint Detection for Microsurgery of Integrated Circuit Devices – by Jim Colvin (presented at ISTFA 2012)

‘In Situ’ Mechanical Sample Preparation of Selected Sites and Components on Large Modules and Boards

Tech Note 15: Tunnel Decapsulation Method for Wire- Bonded Packages

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