Packaging a sealed cavity in an electronic device
An electronic device includes a package substrate, a circuit assembly, and a housing. The circuit assembly is mounted on the package substrate. The circuit assembly includes a first sealed cavity formed in a device substrate. The housing is mounted on the package substrate to form a second sealed cavity about the circuit assembly.
1. A clock generator, comprising:
a substrate having a first sealed cavity, the first sealed cavity containing dipolar molecules;
clock generation circuitry coupled to the substrate, the clock generation circuitry configured to drive a signal into the first sealed cavity and, responsive to the driven signal, generate a clock signal at a frequency of quantum rotational state transition of the dipolar molecules; and
a housing having a second sealed cavity, the second sealed cavity enclosing the substrate and the clock generation circuitry.
2. The clock generator of claim 1 , wherein the substrate is a first substrate, and the clock generator further comprises a second substrate bonded to the housing to form the second sealed cavity.
3. The clock generator of claim 1 , wherein the clock generator further comprises a plate bonded to the substrate to form the first sealed cavity.
4. The clock generator of claim 3 , wherein the plate includes a dielectric membrane.
5. The clock generator of claim 3 , further comprising a pressure sensor coupled to the plate, the pressure sensor configured to measure a pressure within the first sealed cavity responsive to a displacement of the plate.
6. The clock generator of claim 5 , wherein the pressure sensor is a first pressure sensor, and the clock generator further comprises a second pressure sensor coupled to the housing, the second pressure sensor configured to measure a pressure within the second sealed cavity responsive to a displacement of the housing.
7. The clock generator of claim 3 , further comprising:
an acoustic sensor coupled to the plate, the acoustic sensor configured to measure a vibration of the plate; and
control circuitry coupled to the acoustic sensor, the control circuitry configured to measure a pressure within the first sealed cavity responsive to the vibration of the plate.
8. The clock generator of claim 7 , wherein the acoustic sensor is a first acoustic sensor, the control circuitry is first control circuitry, and the clock generator further comprises:
a second acoustic sensor coupled to the housing, the second acoustic sensor configured to measure a vibration of the housing; and
second control circuitry coupled to the second acoustic sensor, the second control circuitry configured to measure a pressure within the second sealed cavity responsive to the vibration of the housing.
9. The clock generator of claim 1 , further comprising a pressure sensor coupled to the housing, the pressure sensor configured to measure a pressure within the second sealed cavity responsive to a displacement of the housing.
10. The clock generator of claim 1 , further comprising:
an acoustic sensor coupled to the housing, the acoustic sensor and configured to measure a vibration of the housing; and
control circuitry coupled to the acoustic sensor, the control circuitry configured to measure a pressure within the second sealed cavity responsive to the vibration of the housing.
11. The clock generator of claim 1 , wherein the first sealed cavity is a waveguide of a millimeter-wave wave chip scale atomic clock.
12. The clock generator of claim 1 , wherein the first cavity is hermetically sealed.
13. The clock generator of claim 12 , wherein the second cavity is hermetically sealed.
14. The clock generator of claim 1 , wherein the second cavity is hermetically sealed.