Zulki’s PCB Nuggets: Medical Miniaturization and PCB Microelectronics Assembly

Medical electronics continue to be a gamechanger, with miniaturization being foremost today in the minds of medical OEMs. In a previous column, I discussed ingestible and implantable medical devices based on remarkably small and unique PCBs, and the technology trends supporting those products continue to dramatically escalate. Today, there is a growing demand for even greater device and component miniaturization that plays a major role in the PCB microelectronics assembly of these medical devices.

Medical miniaturization is rapidly evolving because doctors, hospitals, and other medical care facilities are requiring more functionality, increased portability, and more robustness to upgrade surgical procedures and mobile monitoring equipment. Plus, the highly complex devices successfully interacting with the human body are driving the need for this greater medical miniaturization.

Biosensing and biosensors are at the forefront of this device miniaturization due to their critical nature in today’s medical technology, and they are pushing the limits of electronics manufacturing. In most cases, biosensors are implantable devices that look for diagnostic conditions, such as monitoring a patient’s health conditions in remote areas most of the time.

These biosensing devices require very thin PCBs that are capable of getting into tight spaces in the human body. We are looking at new materials for device manufacturing to be able to accommodate and be compatible with the human body and without causing adverse effects when these miniaturized devices are inserted.

Traditionally, the thinner flex circuit boards are 15 mils or so. Now, with the advent of new technology, we are looking at 5–10 mils of flex board thickness, which are more nimble and flexible to go into smaller places within the human body without much difficulty. Examples of these miniaturized devices include implantable defibrillators, cardiac pacemakers, programmable infusion pumps, continuous glucose monitoring (CGM) devices, and wellness and emergency response safety monitoring systems.

As far as those very thin PCBs, a microelectronics assembly line must be able to deal with this emerging device miniaturization. A PCB microelectronics assembly line must have key operations, such as:

  • Highly precise and accurate flux and solder paste dispensing systems for the traditional SMT manufacturing as well as for extremely precise epoxy dispensing for die attach and encapsulations when using microelectronic manufacturing
  • Extremely accurate component placement systems having within tolerances of ±1-mil accuracy for SMT manufacturing, and tolerances of ±10-micron accuracy when dealing with microelectronics assembly
  • Excellent inspection systems using in-process verification methodologies so that a product has self-verification and correction mechanism built into it for full manufacturing cycle for optimal product creation
  • Final testing tools so that the testing of the final product can be automated, thereby reducing the time to ship the product to the end-users and customers

Aside from having the right PCB microelectronics assembly capabilities, the medical equipment OEM and EMS provider partner must take into account that datasheets for newer miniature devices and components may not yet be available on a large commercial scale. Therefore, it is to their advantage to collaborate early on with device manufacturers to find out about device characteristics, such as electrical, mechanical, thermal, and electromagnetics.

Those include electrical signals, thermal capabilities, and mechanical sturdiness, among other key device characteristics; that’s vitally important since we’re dealing with new materials. Along this line, other top characteristics that must be evaluated include component size, grain structure and size, and the custom processing that may be required for specialized custom components in terms of miniaturization.

Component selection also takes on another level of importance. For instance, take a microcontroller or a similar device that has multiple embedded functionalities into a single chip. Here, power management and thermal capabilities must be investigated so that the component and overall circuitry perform at optimal levels, keeping in mind the speeds at with these signals are operating under normal circumstances.

Simultaneously, considerations must be given to the evolution of these devices and the fact they are increasingly integrated into a human form factor. This means they must continue to be less bulky, lighter in terms of weight, considerably mobile, sturdy, robust, and more dexterous to sustain a long lifetime in the human body.

Further, relatively new terminology is entering into the medical electronics lexicon and is highly pertinent to PCB microelectronics assembly, such as, “The proximity of a device to the human skin or human element.” That is one more thing required for device miniaturization. For example, with artificial pancreases, ocular implants, or prostatic human arms and legs, close scrutiny must be applied to implantable chips and how they react to human fluids and body chemicals for those chips to perform in an optimal way without degrading the integrity of human fluids.

Given today’s trends toward increasing medical device miniaturization, it is highly beneficial for medical equipment OEMs to partner with PCB design and assembly vendors that not only design but also develop the necessary processes at the early stages of new products. Those include component matching and selection for a particular product application, associated power consumption, and other important factors associated with medical miniaturization. Based on these disciplined steps, testing and mass production are performed with minimal efforts.

Zulki Khan is the president and founder of NexLogic Technologies Inc.

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2020

Zulki’s PCB Nuggets: Medical Miniaturization and PCB Microelectronics Assembly

06-24-2020

Medical electronics continue to be a gamechanger, with miniaturization being foremost today in the minds of medical OEMs. Zulki Khan discusses how there is a growing demand for even greater device and component miniaturization that plays a major role in the PCB microelectronics assembly of these medical devices today.

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05-13-2020

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04-15-2020

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Zulki’s PCB Nuggets: Putting the Heat on for Thermal Profiling

03-11-2020

A unique thermal profile is designed for each PCB job undergoing conventional SMT assembly, as virtually every PCB assembly professional knows. But what about a PCB assembly project involving both conventional rigid board and an extraordinarily small rigid or rigid-flex circuit undergoing microelectronics assembly? Zulki Khan covers PCB hybrid assembly, which requires two separate, unique, and distinctly different thermal profiles.

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Zulki’s PCB Nuggets: 7 Steps to Successful Assembly for Medical Devices Using Microelectronics

02-12-2020

Seven major steps need to be taken to achieve successful SMT and microelectronics assembly for medical electronic devices. Zulki Khan explains how these key steps take on special significance for newly emerging implantable and ingestible medical devices and result in medical devices that are robust, smaller, highly reliable, more powerful, and lighter.

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Zulki’s PCB Nuggets: Successful PCB Microelectronics Assembly

01-15-2020

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2019

Zulki’s PCB Nuggets: Vital Details for Implantable Medical Devices

12-04-2019

In addition to smart pills and smart cameras, which Zulki Khan covered in a previous column, another segment of the medical electronics devices market is rapidly growing, as well: implantable medical devices, which medical personnel surgically or otherwise insert into various parts of the human body. Zulki explains the extra measures required for these devices.

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Zulki's PCB Nuggets: Multi-tier Wire Bonding—Diving Into PCB Microelectronics

11-07-2019

As the name implies, multi-tier wire bonding involves several levels of wire bonding beyond the single level of wire bonding, which is traditionally used in semiconductor and/or PCB microelectronics assembly. Here, you have two, three, and four levels of wire bonding, in some cases, called stacked wire bonding. Also, multi-tier wire bonding offers OEMs a solution when the number of inputs/outputs (I/Os) are far beyond the traditional ones that are used in the single wire-bonding application.

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Zulki’s PCB Nuggets: Smart Pills & Cameras—The Next Frontier for PCB Microelectronics

10-23-2019

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Zulki's PCB Nuggets: A Better Grasp of Glob Top Epoxy Factors

09-25-2019

In my last column, I cited important aspects of glob top epoxies, calling attention to the fact there are different epoxy manufacturers. In this column, I will continue to emphasize six other important factors of glob top epoxies.

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Zulki’s PCB Nuggets: Get a Handle on Glob Top Epoxies

09-12-2019

Most often, glob top is the prevalent method EMS providers use today. However, the most important point to be made about glob top is the fact that multiple manufacturers are producing different glob top epoxies. And within each manufacturer, there are numerous types of epoxies being produced. Another key point is that EMS providers and contract manufacturers generally are the ones deciding on the kind of epoxy to use. This column will further describe how you can get a handle on glob top epoxies.

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07-31-2019

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Zulki’s PCB Nuggets: PCB Microelectronics—Inspection and Calibration

07-18-2019

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Zulki’s PCB Nuggets: Three Die Attach Methods for Microelectronics Manufacturing

06-27-2019

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Zulki’s PCB Nuggets: Consider the Integrity of Wire Bonding

06-12-2019

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Zulki’s PCB Nuggets: Avoid PCB Wire-bond Loop Failures

05-30-2019

Today, hybrid PCB manufacturing is making greater inroads into our industry, which is the marriage of traditional SMT manufacturing together with microelectronics and wire bonding. In many cases, the OEM working with EMS providers doesn’t fully understand the nuances of effective wire bonding and related failures.

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2014

Tighter Scrutiny Needed for PCB Cleaning Agents

05-13-2014

PCB cleanliness on the assembly floor is now getting more attention, due to tiny residues and contaminants being left on assemblies after new, advanced assembly processes. Cleaning methodologies, testing, analysis, and special chemistries are being taken to a new level to assure customers of ultraclean boards to avoid costly latent issues.

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Zulki's PCB Nuggets: Tighter Scrutiny Needed for PCB Cleaning Agents

05-13-2014

PCB cleanliness on the assembly floor is now getting more attention, due to tiny residues and contaminants being left on assemblies after new, advanced assembly processes. Cleaning methodologies, testing, analysis, and special chemistries are being taken to a new level to assure customers of ultraclean boards to avoid costly latent issues.

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Uncovering Assembly Problems of High-Speed PCBs

03-12-2014

The high-speed board may be perfect when it comes to BGA assembly. All the balls properly collapse; all the thermal profiles are accurately determined and performed. All soak temperatures, pre-heat, soak, and cool-off periods fall within manufacturer limits and ranges. Yet, this high-speed board fails at high speed at the time of system functional level testing in the system.

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Zulki's PCB Nuggets: Uncovering Assembly Problems of High-Speed PCBs

03-12-2014

The high-speed board may be perfect when it comes to BGA assembly. All the balls properly collapse; all the thermal profiles are accurately determined and performed. All soak temperatures, pre-heat, soak, and cool-off periods fall within manufacturer limits and ranges. Yet, this high-speed board fails at high speed at the time of system functional level testing in the system.

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EMS Discovers Mature IC Technologies

01-14-2014

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Zulki's PCB Nuggets: EMS Discovers Mature IC Technologies

01-14-2014

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2013

Another Look at AOI

11-13-2013

PCB inspection is taking on greater significance as boards and packaging become increasingly smaller, with greater functionality. Automated optical inspection (AOI) and its backup associate, X-ray, team up to catch a variety of board assembly problems. But it's AOI that's at the forefront of this process.

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Zulki's PCB Nuggets: Another Look at AOI

11-13-2013

PCB inspection is taking on greater significance as boards and packaging become increasingly smaller, with greater functionality. Automated optical inspection (AOI) and its backup associate, X-ray, team up to catch a variety of board assembly problems. But it's AOI that's at the forefront of this process.

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Zulki's PCB Nuggets: ECOs Reviewed - The Importance of Accuracy

09-11-2013

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