Methods of manufacturing acoustic wave device with anti-reflection layer
An acoustic wave device is disclosed. The acoustic wave device includes a piezoelectric layer, an interdigital transducer electrode positioned over the piezoelectric layer, and an anti-refection layer over a conductive layer of the interdigital transducer electrode. The conductive layer can include aluminum, for example. The anti-reflection layer can include silicon. The anti-reflection layer can be free from a material of the interdigital transducer electrode. The acoustic wave device can further include a temperature compensation layer positioned over the anti-reflection layer in certain embodiments.
1. A method of manufacturing an acoustic wave device, the method comprising:
providing an acoustic wave device structure with at least one interdigital transducer electrode on a piezoelectric layer;
forming an anti-reflection layer over the interdigital transducer electrode, the anti-reflection layer including silicon; and
etching the interdigital transducer electrode, the anti-reflection layer reducing reflection from the interdigital transducer electrode.
2. The method of claim 1 wherein the interdigital transducer electrode includes aluminum.
3. The method of claim 1 wherein the anti-reflection layer has a reflectivity of 0.2 or less for light having a wavelength of 365 nanometers.
4. The method of claim 1 wherein the interdigital transducer electrode has a reflectivity of at least 0.5 for light having a wavelength of 365 nanometers.
5. The method of claim 1 further comprising forming a temperature compensation layer over the anti-reflection layer.
6. The method of claim 1 wherein the anti-reflection layer remains distinct from the interdigital transducer electrode after a heating process.
7. The method of claim 1 wherein the anti-reflection layer is a silicon oxynitride layer.
8. The method of claim 1 wherein the anti-reflection layer is an amorphous silicon layer.
9. The method of claim 1 wherein the anti-reflection layer is a silicon dioxide layer.
10. The method of claim 1 wherein the anti-reflection layer does not include carbon.
11. The method of claim 1 wherein a line width distribution of the interdigital transducer electrode is 2% of a line width or less.
12. The method of claim 1 wherein the interdigital transducer electrode has a line width in range from 0.25 micrometers to 0.4 micrometers.
13. The method of claim 1 wherein the interdigital transducer electrode includes an aluminum layer and a molybdenum layer.
14. A method of manufacturing an acoustic wave device, the method comprising:
providing an acoustic wave device structure with at least one interdigital transducer electrode on a piezoelectric layer;
forming an anti-reflection layer over the interdigital transducer electrode, the anti-reflection layer having a reflectivity of 0.3 or less for light having a wavelength of 365 nanometers, and the anti-reflection layer remaining distinct from the interdigital transducer electrode after a heating process; and
etching the interdigital transducer electrode, the anti-reflection layer reducing reflection from the interdigital transducer electrode.
15. The method of claim 14 wherein the reflectivity of the anti-reflection layer is 0.2 or less for light with the wavelength of 365 nanometers.
16. The method of claim 14 further comprising forming a temperature compensation layer over the interdigital transducer electrode.
17. A method of manufacturing an acoustic wave device, the method comprising:
providing an acoustic wave device structure with at least one interdigital transducer electrode on a piezoelectric layer, the interdigital transducer electrode including an aluminum layer;
forming an anti-reflection layer over the aluminum layer, the anti-reflection layer remaining distinct from the aluminum layer after a heating process; and
etching the interdigital transducer electrode, the anti-reflection layer reducing reflection from the aluminum layer.
18. The method of claim 17 wherein a reflectivity of the anti-reflection layer is 0.2 or less for light with a wavelength of 365 nanometers.
19. The method of claim 17 wherein the anti-reflection layer is an amorphous silicon layer having a thickness in a range from 5 nanometers to 15 nanometers.
20. The method of claim 17 wherein the anti-reflection layer is a silicon oxynitride layer having a thickness in a range from 100 nanometers to 120 nanometers.