OEM Technology Needs

Peter Lampacher, Head of Design and Development of Vibrant MED-EL

presented by Martin Kerber

iNEMI Medical Electronics Workshop, May 4-5, 2011; Santa Clara, California

Technology needs – Outline

• Advanced Packaging• MEMS• ASIC technologies• Lead-free assembly• Reliability characterization of electronic assemblies• Packaging solutions for implantable electronics outside a

hermetic housing• Interactions between medical equipment and implantable

electronics, with a spotlight on MRI safety

Advanced Packaging• Miniaturization in active implantable devices is driven by

following requirements:– Increased demand for more functionality

• Sensing of body signals• Signal conditioning• Signal processing algorithms of increasing complexity• Stimulation signals• Communication to outside world

– Need for small package size• Anatomical circumstances• Surgical ease

• Miniaturization leads to:– Higher density boards– Substrates with many layers– Smaller components, active and passive– Advanced Packaging

Advanced Packaging Challenges

• Chip Scale Packages (CSPs)– Wafer-Level Re-distribution– Small dies with high number

of I/Os– Standoff– TC mismatch– Underfill– Solder joint reliability

from Toshiba website (http://www.toshiba-components.com/)

Rigid-Flex Substrates

• Required for– High density interconnect– Microvias– Complex geometries with optimum usage of available

volume– 3-dimensional configurations

• Challenges– TC mismatch– Flexing (micro-motion)

MEMS

• Micro-Electro-Mechanical Systems

• Sensor– Accelerometer– Gyroscope– Pressure sensor– Chemo sensor– Bio sensor (Lab on chip)

• Actuator– Micro valves (drug delivery)

from MEMSnet website (http://www.memsnet.org/)

MEMS challenges• Access to Fabrication

– Design– Prototyping– Manufacturing

• Packaging– Many devices need to be in contact with the environment and at the same

time be protected from the environment– Integration with CMOS– Wafer-Level processing– 3D-Integration– Through Silicon Vias– Hermeticity

• Signal conditioning• Testability• Reliability

from Faun AB website (http://www.fauninfrared.com/)

ASIC technologies

• Active implantable medical devices frequently use ASICs for different reasons:– Technical:

• Need to design smaller devices with more features• Full control of all design aspects

– Commercial:• Relatively high cost of ASICs can be justified for AIMDs• Competitive advantage – no need to wait for technology

upgrades of e.g. microcontrollers

ASIC Supply Chain

• The supply chain for ASICs is particularly complex

• Long-term availability of processes is important for medical device OEMs

• Areas of concern are shown on the following slide

Single Chip Design

Mask Set Production(Reticles)

Plain Wafer Production

Wafer Bumping

Wafer Testing

Packaging Tape & Reel

Wafer Dicing

Wafer Dicing

Chips on Foil (Verification Purposes)

Fab

Designer

Wafer-levelprocessing

Test house

Typical supply chain of an ASIC

Circuit board assembly

Assembly

Can be problematic

Can be problematic

Lead-free assembly

• Per EU directives (2002/95 – RoHS and 2002/96 – WEEE) medical products are (still) exempt from RoHS requirements– Leaded assemblies are still allowed– Long-term commercial availability of leaded

components is uncertain– Most concern with respect to implanted system parts

Pb?

A CSP-and-MLCC-and-others-on-flexhybrid on a 6-layer FR4

Reliability characterization of electronic assemblies

• Several approaches:– MIL-HDBK-217 is still used and supported by FMEA / Reliability

Prediction software• Latest version is rev. F change notice 2 from 1995 (!)

– HALT / HAST testing• „1000h test“ (per MIL-STD-883)• 85°C / 85% rH testing (JEDEC Standard No. 22 -A101)

– Combined approaches (e.g. long term saline soak)

• Electronics reliability is an important contribution to overall device reliability. Other components (e.g. hermetic seals) also contribute and have to be considered.

Example...

• One-stop shop for reliability and safety?

• MIL-HDBK-217 is advertised to be globally accepted

• There is a clear need for updated/improved reliability design and test standards

from Reliacore website (http://www.reliacore.eu/)

Packaging solutions for implantable electronics outside a hermetic housing

• Novel implant applications currently emerging...– some examples shown from the Healthy AIMS EU

project– Conventional hermetic packages difficult to use for

these applications

Glaucoma sensor

from Healthy AIMS website (http://www.healthyaims.org/)

Obviously no room for a conventional hermetic encapsulation

Retina implant

from Healthy AIMS website (http://www.healthyaims.org/)

Obviously no room for a conventional hermetic encapsulation

Intracranial Pressure Sensor

from Healthy AIMS website (http://www.healthyaims.org/)

The whole device has to be surgically placed inside the cranium!

Challenges ...

• Materials• Test methods• Permanent exposure to moisture: Implications

on electronics design– Limited selection of components, substrates

Interactions between medical equipment and implantable electronics

• A well-known symbol...– but many users of pacemakers

and other active implants are in need of MRI examinations.

• FDA approved the first pacemaker with „MRI conditional“ labelling in Feb 2011.

MRI evolution... and interactions with other medical devices

1.5T 3T

Specialized sequences

Fast gradient switching

0.3T

More heating

Induced voltages

...

Images from MED-EL, Medtronic websites

Time

Marketing of MRI manufacturers

• Improvements of clinical use (high resolution, fast scans)

• ... but how about compatibility with medical implants?– Adoption of standardized „implant-safe“

MRI sequences by the manufacturers could contribute to improve the situation

• Potentially applicable to other diagnostic devices

Images from Siemens Medical and GE Healthcare websites

Summary – 1

• Advanced Packaging– Packaging topics already addressed in iNEMI projects– Address in a separate project out of the Medical TIG?

• MEMS– Packaging issues related to IC packaging– Potential area for iNEMI activity?

• ASIC technologies– Many semiconductor manufacturers are with iNEMI, but not

many wafer foundries– Potential area for iNEMI activity?

• Lead-free assembly– iNEMI is a leader (Board assembly TIG)– Potential synergy?

Summary – 2

• Reliability characterization of electronic assemblies– A component-level project was completed (MLCC project).– Industry participation for a follow-up project?

• Packaging solutions for implantable electronics outside a hermetic housing– Future topic– Within scope for iNEMI?

• Interactions between medical equipment and implantable electronics, with a spotlight on MRI safety– Major topic in implant industry– Any way to address this through iNEMI?

Questions?