US 12,078,615 B2
Photoacoustic detector unit, photoacoustic sensor and associated production methods
Rainer Markus Schaller, Saal a.d. Donau (DE); Matthias Eberl, Taufkirchen (DE); Simon Gassner, Munich (DE); Franz Jost, Stuttgart (DE); and Stefan Kolb, Unterschleissheim (DE)
Assigned to Infineon Technologies AG, Neubiberg (DE)
Filed by Infineon Technologies AG, Neubiberg (DE)
Filed on May 24, 2023, as Appl. No. 18/322,755.
Application 18/322,755 is a division of application No. 17/247,134, filed on Dec. 1, 2020, granted, now 11,733,213.
Claims priority of application No. 102019134267.8 (DE), filed on Dec. 13, 2019.
Prior Publication US 2023/0296567 A1, Sep. 21, 2023
Int. Cl. G01N 29/24 (2006.01); G01N 33/00 (2006.01)
CPC G01N 29/2425 (2013.01) [G01N 33/0004 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method, comprising:
bonding a first wafer, composed of a first material, to a second wafer, composed of a second material, in a reference gas atmosphere to form bonded wafers,
wherein a plurality of hermetically sealed cavities are formed,
wherein the plurality of hermetically sealed cavities enclose a reference gas of the reference gas atmosphere; and
singulating the bonded first and second wafers into a plurality of photoacoustic transducers for a photo acoustic detector unit,
wherein each photoacoustic transducer, of the plurality of photoacoustic transducers, comprises a respective hermetically sealed cavity, of the plurality of hermetically sealed cavities, and
wherein each photoacoustic transducer, of the plurality of photoacoustic transducers, is configured to cover an opening of a housing of a photoacoustic detector unit to form an acoustically tight cavity.