Methods for patterning electrodes of 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 for patterning electrodes to connect an electrical component to an electrical circuit, the method comprising:
providing the electrical component, the electrical component including a first plurality of electrodes;
aligning the electrical circuit with the electrical component, the electrical circuit having a second plurality of electrodes, each electrode of the second plurality of electrodes aligned with a corresponding electrode of the first plurality of electrodes;
depositing a composite dielectric material on the first plurality of electrodes and the second plurality of electrodes, wherein the composite dielectric material includes a matrix material and a particulate material;
forming an electrode pattern by laser ablating at least a portion of a surface of the composite dielectric material to remove the matrix material, increase a surface area of the composite dielectric material, and expose the first plurality of electrodes and the second plurality of electrodes in the electrode pattern, the laser ablating including:
laser ablating the matrix material at a lower fluence than the particulate material; and
creating a trench in the composite dielectric material between each of the second plurality of electrodes and the corresponding electrode of the first plurality of electrodes;
depositing a conductive metal on areas ablated by the laser ablating;
depositing a resist on the conductive metal, wherein the resist is thicker over the first plurality of electrodes, the second plurality of electrodes, and the trenches compared to other ablated areas ablated by the laser ablating;
removing a portion of the resist not forming part of the electrode pattern to expose a portion of the conductive metal in a second pattern that is a negative of the electrode pattern; and
etching the exposed portion of the conductive metal in the second pattern to produce a connection between the electrical component and the electrical circuit in the electrode pattern.
2. The method of claim 1 , further comprising:
after etching the exposed portion of the conductive metal, laser ablating areas of etched conductive metal to remove at least a portion of the composite dielectric material therein.
3. The method of claim 2 , wherein in the laser ablating of areas of etched conductive metal, substantially all of the composite dielectric material and a portion of the electrical component lying under the areas of etched conductive metal are ablated.
4. The method of claim 2 , wherein laser ablating at least a portion of the composite dielectric material to remove matrix material and increase the surface area of the composite dielectric material comprises using a fluence of up to 5 J/cm.sup.2.
5. The method of claim 1 , wherein the laser ablating of at least the portion of the surface of the composite dielectric includes laser ablating by a short wavelength laser.
6. The method of claim 1 , wherein the removing and etching are performed by a laser having a fluence less than 0.8 J/cm.sup.2.
7. The method of claim 1 , wherein the electrical component is an ultrasound transducer.
8. The method of claim 7 , wherein the first plurality of electrodes are elements of an array of the ultrasound transducer.
9. The method of claim 1 , wherein the composite dielectric material is a silica particle filled epoxy.
10. The method of claim 1 , further comprising removing a remaining portion of the resist by using a solvent to dissolve the resist.