Request Expert

He has demonstrated expertise in hermetic sealing and leak testing processes for cavity style packaged microcircuits intended for high reliability military, aerospace and Class III medical implants. He has worked as a hermeticity consultant for prominent military and aerospace companies and has been engaged in several hermeticity projects for medical device manufacturers, including serving as an on going expert witness in a cochlear implant device failure litigation. He is the preferred consultant for a major military OEM because of his proven expertise in solving problems related to high moisture and hermeticity failures of microcircuits used in critical military system.

He has conducted experiments and presented technical papers at NIST and IMAPS on leak testing techniques and optimization of hermetic welding processes. He coauthored the most recent revision to Mil-Std-883 TM 1014 (Seal), the industry standard for hermeticity testing. He regularly attends the EIA/JEDEC meetings and serves on the committees looking to revise the hermeticity specification. Hermeticity testing along with moisture and gas content inside microelectronic packages is of critical importance for device reliability. He is experienced in reading and interpreting RGA test results. He teaches the only industry full day course on hermeticity testing titled …Hermeticity Testing, RGA and “Near Hermetic” Packaging Concepts. This course describes the standard helium based fine leak test techniques along with gross leak methods, bubble testing, Optical Leak Test (OLT), Radioisotope Kr-85 and Cumulative Helium Leak Detection (CHLD). He also teaches a half day course on Hermeticity of Small Volume MEMS packages.

He has pioneered the use of moisture sensors mounted inside the package to monitor real time moisture ingress into and out of the cavity. He also has experience evaluating “non hermetic” packages and recently chaired an industry Advanced Technology Conference on the topic of “non-hermetic” packages for reliable microelectronics.

He has considerable expertise in materials and manufacturing processes used in building custom high reliability microcircuits (Hybrids, MCMs and RF microwave modules) for military and aerospace applications. He has demonstrated expertise and previous consulting experience in wirebonding, component attach, hermetic package seal and test, and other aspects of microcircuit assembly. Specific areas of expertise include: gold ball bonding, deep access bonding, fine wire (.7 mil ) bonding to FETs, aluminum wedge bonding, heavy aluminum wire, component attach, including epoxy and AuSn eutectic die attach of GaAs devices, hermetic seal/testing, gold and nickel plating processes and foreign material identification and control.

He has led numerous failure analysis and root cause investigations into component failures from qualification lots and field failures, in some cases with millions of dollars of product inventory hanging in the balance. In a recent FA investigation he relied on SEM, Auger and other advanced analytical methods to determine root cause failure and corrective actions of a serious production problem regarding aluminum wedge bond lifts from a thick film gold trace. In another recent root cause investigation his knowledge of hermeticity testing, epoxy outgassing characteristics and RGA data analysis led to successful resolution of a hermetic package problem with high moisture.

He has conducted and analyzed numerous statistically designed experiments (DOE). Specifically in the area of wirebond and eutectic component attach. His experiments and data analysis increased first past yield, reduced costs and improved product quality. Early in his career he routinely analyzed component failures from Air Force avionic equipment and initiated the Air Force Field Failure Return Program.

In addition to material, process and FA expertise he has a wealth of knowledge concerning the visual inspection criteria for microelectronics intended for use in military systems. He teaches a number of different courses in industry on these topics and is often called in as a consultant to help referee quality issues and Mi-Std-883 compliance. He is currently the JEDEC chair person responsible for revision of Mil-Std-883 TM 2017 Pre Cap visual. He has been involved in microelectronic visual inspection standards for 20 years and has authored an industry workmanship manual and was contracted to draft the NASA/JPL internal workmanship standards for microelectronics.

He spent six months on a project as part of a team of multi disciplined engineers that investigated root cause failure of a hermetic microcircuit package due to elevated moisture. The high moisture RGA (residual gas analysis) qualification failures jeopardized the entire production lot. Multiple process and material DOEs were conducted and involved the use of the Cumulative Helium Leak Detection method (CHLD) and RGA as the response variables. He was sent in plant to investigate the seam seal and pre seal vacuum bake processes. He was instrumental in the FA and root cause investigation that finally pointed to an epoxy out-gassing problem and timely resolution. He analyzed and identified the failure mechanism for a heavy aluminum wire (10 and 15 mil) to thick film gold wire-bond process. Bond lifts during temperature cycling in screening and qualification were occurring at an alarming rate. Review of the pull test and shear data, followed by extensive analysis via SEM, Auger ect., and multiple DOEs help to isolate the cause of failure to a cleaning process step that was occurring prior to wire-bond. Process changes were made and the problem was eliminated. He developed and optimized a gold/tin eutectic die attach process using a scrub assisted program on the Palomar 3500 die bonder. The process involved a void free attach of a GaN (gallium nitride) chip to a CMC (copper-moly-copper) heat spreader. X-ray testing, acoustic imaging and numerous cross sections were used to verify the 95% void free eutectic solder interface underneath the active device. He has developed similar eutectic attach processes with GaAs (gallium arsenide) MMICs attached to heat spreaders using a fluxless vacuum assisted process. Drafted and delivered a complete hybrid microelectronics workmanship guide and quality manual for NASA. The six month project included collecting defect photos and drafting from scratch the entire text. The manual not only served as a compliance document for Mil-Std-883, but also contained numerous other sections and references to use a guide for new process, design and quality engineers. He analyzed leak test data and results from qualification screening tests along with review of the drawing to identify a package defect from a critical off shore supplier. Organized controlled DOE experiments and follow up testing to determine the root cause of the cracking in a metal-ceramic package. Identified the design flaw in the sidewall braze and helped guide the hermetic package redesign that ultimately solved the problem.