Alert: Export Control Check Required
Thank you for requesting a TWI Industrial Members Report.
To meet UK government requirements, your request will undergo an Export Control Check. This process reviews the technical content of the report, identifies the end user, and addresses any concerns.
Please submit your request to CRP@twi.co.uk including your name, member company that you work for and your location. We will contact you regarding the request within 2 working days and any additional information required to complete the necessary checks.
We look forward to receiving your request and processing it through our export control procedure.
Thank you,
TWI CRP Operations Team
This content is only available to Industrial Members, Find out how to become a Member of TWI.
TWI Industrial Member Report Summary 417/1990
S T Riches
Scope
Ni-Cr strain gauges are used extensively on pressure transducers. Interconnections to the strain gauges are normally made by Au plating the Ni-Cr thin film metallisation which is then thermosonic or thermocompression bonded with Au wire (typically 25-33µm diameter). There is interest in bonding directly to the Ni-Cr thin film metallisation, thereby eliminating the Au plating process. There is a corresponding desire to eliminate the Au plating operation from the external connections so that wire bonding can take place to unplated Cu on printed circuit board material.
This report investigated the feasibility of ultrasonic wire bonding of (25µm diameter) Au, Al-1%Si and Cu wire to Ni-Cr thin film metallisations on glass. Data on the consistency and reliability of Al-1%Si ultrasonic wedge bonds to Ni-Cr thin film metallisations on glass and Cu tracks on printed circuit board are presented.