Method and system for wafer-level tuning of bulk acoustic wave resonators and filters by reducing thickness non-uniformity
AssigneeNokia Mobile Phones Ltd.
InventorsJyrki Kaitila, Pasi Tikka, Juha Ellä
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Abstract
A method and system for tuning a bulk acoustic wave device at wafer level by reducing the thickness non-uniformity of the topmost surface of the device using a chemical vapor deposition process. A light beam is used to enhance the deposition of material on the topmost surface at one local location at a time. Alternatively, an electrode is used to produce plasma for locally enhancing the vapor deposition process. A moving mechanism is used to move the light beam or the electrode to different locations for reducing the thickness non-uniformity until the resonance frequency of the device falls within specification.
Claims28
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, 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 in a chemical vapor deposition apparatus, wherein the chemical vapor deposition apparatus contains a gaseous precursor for depositing material over the surface layer for reducing the thickness non-uniformity, said method comprising the steps of:
- providing an enhancing medium for locally enhancing the deposition of material on the surface layer at a location;
- and
- relocating the enhancing medium in a lateral direction relative to the surface layer to at least one different location for locally enhancing the deposition of material on the surface layer at said at least one different location.
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 and a surface layer thickness having a non-uniformity profile, 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 in a chemical vapor deposition apparatus, wherein the chemical vapor deposition apparatus contains a gaseous precursor for depositing material over the surface layer for reducing the thickness non-uniformity, said system comprising:
- means, for providing an enhancing medium for locally enhancing the deposition of material on the surface layer at a location;
- and
- a moving mechanism, operatively connected to the providing means, for relocating the enhancing medium in a lateral direction relative to the surface layer to at least one different location for locally enhancing the deposition of material on the surface layer at said at least one different location.
Dependencies are inferred from the claim text.