Patent ID: 7350416

Claim:
An apparatus for determining properties of a thin film, said apparatus comprising: a piezoelectric substrate having a surface; a slanted finger interdigital transducer unit provided on said surface of said piezoelectric substrate, and including a first transmitter port that includes first and second electrodes, each of which includes a plurality of electrode fingers, each of said electrode fingers of each of said first and second electrodes of said first transmitter port having opposite first and second ends, said first ends of adjacent ones of said electrode fingers of said first electrode of said first transmitter port defining a distance therebetween that is less than that between said second ends of said adjacent ones of said electrode fingers of said first electrode of said first transmitter port, said first ends of adjacent ones of said electrode fingers of said second electrode of said first transmitter port defining a distance therebetween that is greater than that between said second ends of said adjacent ones of said electrode fingers of said second electrode of said first transmitter port, and a first receiver port that includes first and second electrodes, each of which includes a plurality of electrode fingers, each of said electrode fingers of each of said first and second electrodes of said first receiver port having opposite first and second ends, said first ends of adjacent ones of said electrode fingers of said first electrode of said first receiver port defining a distance therebetween that is less than that between said second ends of said adjacent ones of said electrode fingers of said first electrode of said first receiver port, said first ends of adjacent ones of said electrode fingers of said second electrode of said first receiver port defining a distance therebetween that is greater than that between said second ends of said adjacent ones of said electrode fingers of said second electrode of said first receiver port; and a mask disposed above said surface of said piezoelectric substrate, and defining a hole therethrough to expose a portion of said surface of said piezoelectric substrate between said first transmitter port and said first receiver port.