Methods for Manufacturing Ultrasound Transducers and Other Components
The disclosed technology features methods for the manufacture of electrical components such as ultrasound transducers. In particular, the disclosed technology provides methods of patterning electrodes, e.g. in the connection of an ultrasound transducer to an electrical circuit; methods of depositing metal on surfaces; and methods of making integrated matching layers for an ultrasound transducer. The disclosed technology also features ultrasound transducers produced by the methods described herein.
1 . A method of forming an ultrasound matching layer, the method comprising:
providing an acoustic array transducer stack comprising a piezoelectric layer and having a top surface and a plurality of array elements, the top surface comprising a plurality of spacers not disposed over the plurality of array elements;
providing a lens assembly having a top surface and a bottom surface;
contacting the bottom surface of the lens assembly with the plurality of spacers; and
curing an adhesive between the top surface of the transducer stack and the bottom surface of the lens assembly to form the ultrasound matching layer, the adhesive configured to bond to the bottom surface of the lens assembly and to the top surface of the transducer stack, a distance between the top surface of the transducer stack and the bottom surface of the lens assembly resulting from the plurality of spacers being an appropriate wavelength thickness for the ultrasound matching layer.
2 . The method of claim 1 , wherein the lens assembly comprises a lens and a second matching layer forming the bottom surface of the lens assembly.
3 . The method of claim 2 , wherein the lens comprises Rexolite or polymethylpentene (TPX).
4 . The method of claim 2 , wherein the second matching layer comprises cyanoacrylate.
5 . The method of claim 2 , wherein the second matching layer adheres directly to the lens.
6 . The method of claim 1 , wherein the transducer stack further comprises a plurality of first kerf slots that extend a first depth into the transducer stack, and wherein the plurality of first kerf slots define the plurality of array elements.
7 . The method of claim 6 , wherein the first depth follows a depth profile that is a function of position along a length of a respective first kerf slot of the plurality of first kerf slots.
8 . The method of claim 6 , wherein the transducer stack further comprises a plurality of second kerf slots that extend a second depth therein the transducer stack, wherein each second kerf slot is positioned adjacent to at least one first kerf slot, and wherein the plurality of second kerf slots define a plurality of array sub-elements.
9 . The method of claim 8 , wherein the second depth follows a depth profile that is a function of position along a length of a respective second kerf slot of the plurality of second kerf slots.
10 . The method of claim 1 , wherein the transducer stack further comprises third and fourth matching layers disposed between the piezoelectric layer and the ultrasound matching layer.
11 . The method of claim 1 , further comprising lapping the spacers to a final height of the ultrasound matching layer.
12 . The method of claim 1 , wherein particles are employed in the adhesive, and wherein the method further comprises employing nano-particle dopants in the adhesive prior to curing the adhesive.
13 . The method of claim 1 , wherein the plurality of array elements operate at a center frequency of at least 20 megahertz.
14 . A method of depositing a material on a surface, the method comprising:
providing a composite dielectric substrate comprising a matrix material and a particulate material;
laser ablating a surface of the composite dielectric substrate at a fluence sufficient to ablate the matrix material but not the particulate material to form an ablated surface having greater surface area than the surface of the composite dielectric substrate; and
depositing the material on the ablated surface, wherein a strength of adhesion of the material to the ablated surface of the composite dielectric substrate is greater than that of the material to an unablated surface of the composite dielectric substrate.
15 . The method of claim 14 , wherein the matrix material comprises a polymer.
16 . The method of claim 14 , wherein the particulate material comprises silica or silicon carbide.
17 . The method of claim 14 , wherein the material deposited on the ablated surface is a metal or adhesive.
18 . The method of claim 14 , wherein the material deposited on the ablated surface is gold, and the method further comprises applying an adhesion layer prior to depositing the material on the ablated surface.
19 . The method of claim 18 , wherein the adhesion layer contains chromium.
20 . The method of claim 14 , wherein the laser ablating is performed by a short wavelength laser.