Development of a Small-Footprint 50 MHz Linear Array: Fabrication and Micro-Ultrasound Imaging Demonstration.

Area of Science:

• Biomedical Engineering
• Ultrasound Technology
• Medical Device Fabrication

Background:

• Compact high-frequency arrays are crucial for clinical and preclinical applications requiring small-footprint or endoscopic devices.
• Current fabrication methods for compact arrays lead to increased footprint due to interconnections.
• Existing methods like wire bonding and conductive adhesives are not optimal for miniaturization.

Purpose of the Study:

• To develop a novel interconnection method for fabricating compact, high-frequency ultrasound arrays.
• To achieve a right-angle, compact, and reliable connection between array elements and flexible circuits.
• To reduce the overall footprint of the ultrasound array for improved endoscopic applications.

Main Methods:

• Utilized vacuum-deposited metals, laser patterning, and electroplating for interconnection.
• Thickened array element edges with patterned copper traces to enhance connection.
• Fabricated a 2.3 mm x 1.7 mm, 64-element linear array with a 36 μm pitch.

Main Results:

• The interconnect added only 100 μm to each side of the array.
• Achieved an average center frequency of 55 MHz with a -6 dB bandwidth of 41%.
• Measured imaging resolutions of 35 μm (axial) and 114 μm (lateral).

Conclusions:

• The proposed interconnection method enables the fabrication of significantly more compact high-frequency ultrasound arrays.
• Demonstrated successful ex vivo and in vivo imaging, validating the performance of the developed arrays.
• This advancement facilitates the development of smaller, more effective endoscopic ultrasound devices for various medical applications.