Destructive Physical Analysis (DPA) Testing for Hybrid Microcircuits

Hybrid Microcircuits are typically a combination of discrete active and passive components that form a particular function essential to nearly all electronic systems. Due to their wide-ranging applications, packaging of Hybrid Microcircuits will vary in construction design and materials to meet environmental, power, application or systems requirements. Multi-chip modules are included with hybrid assemblies and subjected to the same testing methods for DPA.

Typical Hybrid Microcircuit packages include hermetic metal packages with lid seam welds or solder seals, as well as lead glass frit seals. Non-hermetic plastic encapsulated hybrid packages are also used in some applications. Both are prevalent in Aerospace, Military and Automotive systems. Within the scope of Aerospace applications, Hybrid Microcircuit devices are subjected to qualification requirements to MIL-PRF-38534 and/or Methods for DPA to MIL-STD-1580 and MIL-STD-883.

Hybrid Hermetic Package

TO-247 plastic encapsulated microcircuit

Hybrid Hermetic Package

SOT-23 plastic encapsulated microcircuit

Hybrid Hermetic Package

ORS Offers FAST Reliable Hybrid Microcircuit DPA

Hybrid Microcircuit(s) package variations require specific test methods to screen for manufacturing defects specified in DPA testing based military performance specifications (MIL-PRF) and design drawings.

Hybrid Microcircuits for Aerospace applications must meet the DPA requirements MIL-STD-1580 Requirement 16 that specifies testing to primarily methods of MIL-STD-883. Specific test methods will vary based on applicability to the design or construction. All designs require external visual inspection, X-ray radiography and some form of internal visual inspection. Prohibitive metals analysis (PMA) for elemental constituents of packaging materials may also be applicable.

Testing of hermetic packages requires testing to MIL-STD-883, which includes hermeticity testing to Method 1014 and Internal Gas Analysis (IGA) Method 1018, as well as wire bond strength and die shear testing Methods 2011 and 2019. SEM metal inspection to Method 2018 of integrated and semi-conductor die may also be required.

Plastic encapsulated devices typically require acoustic microscopy, dye impregnation for flux and moisture pathways with cross-sectional inspection of interfaces, bond pull (if applicable) and SEM metal test methods, depending upon metallization patterns as specified in Requirement 16.5 of Mil-Std-1580.

Cross-sectional view of secondary copper bond with acceptable effective bond area

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Destructive Physical Analysis

ORS has over 40 years of experience performing comprehensive testing designed to identify anomalies that can lead to field failure.

ORS DPA techniques for Hybrid Microcircuits have effectively revealed imperfections that include: improper package markings, hermetic seal failures related to lid seal and glass feed-through anomalies, bond wire placement, bi-metallic bonding intermetallic formations and wire-to-lid clearance, foreign material, die chip-outs and attachment voiding, plating deposit adhesion issues, chip capacitor termination formations, substrate thick film laser-trim and die-metal voiding, and contact-step thinning.

Non-Destructive Test Methods

An important part of a Hybrid Microcircuit DPA are the applicable initial non-destructive testing methods – external visual inspection with physical dimensions/configuration compliance, X-ray radiography, acoustic microscopy for plastic encapsulated, hermeticity, particle-induced noise detection (PIND), prohibited material analysis (PMA) by X-ray fluorescence elemental analysis (XRF) or scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) along with fourier transform infrared microscopy (FTIR).* These methods can be essential to determining subsequent destructive test methods.

*FTIR is commonly included in baseline DPA or Construction Analysis (CA) type analyses to document functional groups detected in mold compounds and other organic features (i.e., die conformal coating and leadframe adhesives).

Exterior visual of package

Y-axis X-ray View

Z-axis X-ray view

Glass frit seals

Y-axis X-ray view

Glass seal with square lead

Destructive Analysis Methods of Hybrid Microcircuit Testing

A complete DPA of a Hybrid Microcircuit would include destructive test methods such as Internal Gas Analysis (IGA) and internal visual inspection achieved by de-lidding/de-encapsulation. It may also include cross-sectioning, bond strength and die shear testing methods. Hybrid Microcircuit dies with expanded metal require scanning electron metal inspection (SEM). SEM with energy dispersive X-ray (EDS) analysis may be utilized for internal prohibitive materials analysis testing.