Case Study – Multinational Medical Device Companies Turn to Plasma Measurement to Improve Process Yield


The Challenge

Plasma processing is used extensively in medical device manufacturing. Applications include the modification of surfaces (to improve adhesion or reduce friction), sterilization and bio-compatible coatings for implants.

Impedans assist several multinational medical device manufacturers to implement plasma measurement solutions to improve process performance and reduce product scrap. We develop applications to detect RF related issues, such as arcing and equipment malfunction. These help to improve tool  performance and increase product yield. The main applications are summarized as follows:

  • Direct ion current measurement to detect plasma ignition failure at intervals through a 50 Hz power cycle, in processes used for catheter treatment.
  • RF matching unit tracking at millisecond report rates for sub-second RF sterilization processes.
  • Direct ion energy measurements on multiple shelves (simultaneously) in stent and catheter plasma processing chambers.
  • RF impedance monitoring and arc detection for process monitoring of plasma chambers used for treating various in-vitro medical devices.
The Process

The Impedans product development team consults with the customer to find the optimum plasma sensing solution for their application. A custom sensing solution is proposed. Upon approval, a sensor that meets specific customer specification is manufactured and installed.

Our software team work in tandem with the company’s IT team to identify a solution for data management if necessary. Data is captured for a range of experimental conditions and this is analyzed to identify fault signatures. Impedans then propose corrective action procedures.  The customer can also avail of the Impedans Protect support packages to maintain the accuracy of the custom sensing platform long into the future.

Our Solution

A custom Langmuir probe design and algorithm for a 50 Hz ignition failure application.

The Langmuir probe was installed in place of the catheter. The measurements clearly showed periods when the plasma did not strike, leading to unprocessed regions of the catheter. These measurements enabled the customer to fine tune the equipment and solve the issue.

The Octiv RF sensing platform is ideal for millisecond tracking of the matching network in the RF sterilization process. The customer also made use of the industrial  EtherNet/IP protocol for process monitoring.

A custom Semion (Retarding Field Energy Analyzer) was developed for a multi-shelf plasma processing chamber application. This system highlighted that plasma was failing to ignite between some shelves leading to stent/catheter scrap. This data pointed to the source of the problem and allowing immediate improvement in tool performance.

The Octiv RF platform and Alfven event detector platform were used to monitor plasma impedance and RF arcs in a process used for in-vitro medical device processing. This provided the customer with invaluable data for their process monitoring and control applications.

Value Add

Impedans has considerable expertise in plasma and RF. Medical Device companies leverage this to optimize their plasma processing issues. Sensing and data  management systems are tailored to the needs of each individual customer. In all cases the return on investment far exceeds the cost of implementation. As medical device manufacturing becomes more complex and production volumes are ramped up, smart sensing and data management capabilities are indispensable.

  • Critical Process Problems Solved
  • Increased Throughput
  • Improved Process Performance
  • Outsourced RF & Plasma Expertise
  • Return on Investment Far Exceeds Installation Costs