Method and system for wafer-level tuning of bulk acoustic wave resonators and filters
AssigneeNokia Corporation
InventorsPasi Tikka, Juha Ella, Jyrki Kaitila
Life of this patent
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Abstract
A method and system for tuning a bulk acoustic wave device at wafer level, wherein the thickness of topmost layer of the device is non-umiform. The thickness non-unifornity causes the resonant frequency of the device to vary from one location to another location of the topmost layer. A laser beam, operatively connected to a beam moving mechanism, is used to locally trim the topmost layer, one location at a time.
Claims16
A method of tuning a bulk acoustic wave device comprising a plurality of acoustic wave generating and controlling layers formed on a substrate, wherein the bulk acoustic wave device has a surface layer and a surface layer thickness having a non-uniformity profile defining a plurality of locations at which the layer surface requires thickness adjustment, and wherein the bulk acoustic wave device has an operating frequency which varies partly with the surface layer thickness, and the operation frequency can be adjusted by adjusting the surface layer thickness, said method comprising the steps of:
- providing an etching medium over the surface layer at one section thereof for adjusting locally the thickness of at least one location of the surface layer at a time;
- relocating the etching medium, relative to the device, to another section of the surface layer for adjusting the thickness of at least one other location of the surface layer;
- and
- repeating the relocating step if at least one remaining location of the surface layer requires thickness adjustment.
A system for tuning a bulk acoustic wave device comprising a plurality of acoustic wave generating and controlling layers formed on a substrate, wherein the bulk acoustic wave device has a surface layer made of a surface material and a surface layer thickness having a non-uniformity profile defining a plurality of locations at which the surface layer requires thickness adjustment, and wherein the bulk acoustic wave device has an operating frequency, which varies partly with the surface layer thickness, and the operation frequency can be adjusted by adjusting the surface layer thickness, said system comprising:
- means, positioned above a section of the surface layer, for adjusting locally the thickness of at least one location of the surface layer at a time;
- and
- means for relocating the thickness adjusting means, relative to the device, to another section of the surface layer for adjusting the thickness of at least one other location of the surface layer.
Dependencies are inferred from the claim text.