Sensor device including sensor unit for a gaseous medium
A sensor device includes a sensor unit sensitive for a property of a gaseous medium. The sensor unit is formed on a first surface of a sensor substrate. A frame structure on the first surface includes a first loop portion laterally surrounding a first area that includes the sensor unit. A communicating channel accesses the first area through at least one of a lateral port in the first loop portion and a base port in the sensor substrate. A lid structure completely covers the frame structure and the first area.
1. A method of manufacturing a sensor device, the method comprising:
forming a sensor unit sensitive for a property of a gaseous medium on a front surface of a semiconductor substrate;
forming a frame structure on the front surface, wherein the frame structure comprises a first loop portion laterally surrounding a first area comprising the sensor unit, a second loop portion laterally surrounding a second area, and a connection portion connecting the first loop portion with the second loop portion to form a communicating channel between the first and second areas;
forming a lid structure on the frame structure; and
forming, in the lid structure, a lid opening exposing the second area.
2. The method according to claim 1 , wherein the lid structure is formed spaced from a sensitive surface of the sensor unit sensitive to the property of the gaseous medium.
3. The method according to claim 1 , wherein forming the frame structure comprises depositing a photoresist layer and patterning the photoresist layer to form the frame structure from an exposed section of the photoresist layer.
4. The method according to claim 1 , wherein forming the lid structure comprises:
attaching a photoresist laminate to an exposed upper edge of the frame structure; and
patterning the photoresist laminate to form a preparatory lid structure without any lid opening exposing the second area.
5. The method according to claim 4 , wherein forming the lid structure comprises performing a laser treatment of the preparatory lid structure to form the lid opening.
6. The method according to claim 4 , further comprising forming a reflective structure in the second area before forming the lid structure.
7. The method according to claim 4 , further comprising forming an auxiliary lid selectively in a first portion of the second area, wherein the auxiliary lid is connected to the frame structure and spaced from the front surface.
8. The method according to claim 7 , wherein
the auxiliary lid is formed from a further portion of a photoresist layer forming the frame structure and exposure of the further portion of the photoresist layer to form the auxiliary lid is effective only in a vertical section of the photoresist layer.
9. The method according to claim 7 , wherein the lid opening is formed to expose a portion of the auxiliary lid during formation of the lid structure.
10. The method according to claim 9 , wherein forming the lid opening comprises forming an auxiliary lid opening in a vertical projection of the lid opening in the lid structure.
11. A sensor device comprising:
a sensor unit sensitive for a property of a gaseous medium disposed on a front surface of a semiconductor substrate;
a frame structure disposed on the front surface, wherein the frame structure comprises a first loop portion laterally surrounding a first area comprising the sensor unit, a second loop portion laterally surrounding a second area, and a connection portion connecting the first loop portion with the second loop portion to form a communicating channel between the first and second areas; and
a lid structure disposed on the frame structure, the lid structure comprising a lid opening exposing the second area.
12. The sensor device of claim 11 , wherein the lid structure is spaced from a sensitive surface of the sensor unit sensitive to the property of the gaseous medium.
13. The sensor device of claim 11 , wherein the second area comprises a reflective structure.
14. The sensor device of claim 11 , wherein the sensor unit comprises selective receptor sites sensitive a to one or more species of molecules.
15. A sensor device comprising:
a sensor box encasing a first area that comprises a sensor unit sensitive for a property of a gaseous medium, wherein the sensor unit is formed on a first surface of a sensor substrate and the sensor box comprises a lateral port;
an inlet box adjacent to the sensor box, partially encasing a second area and comprising a lid opening opposite to the first surface; and
a conduit comprising a communicating channel formed on the first surface and extending from the lateral port of the sensor box to a lateral port of the second area.
16. The sensor device of claim 15 , further comprising a reflective structure disposed on the first surface of the sensor substrate within the second area.
17. The sensor device of claim 15 , wherein the sensor unit comprises at least one suspended membrane.
18. The sensor device of claim 17 , wherein the at least one suspended membrane spans across a hermetically closed cavity.
19. The sensor device of claim 15 , wherein the sensor device further comprises an outlet box partially encasing a third area, wherein the communicating channel further extends from the sensor box to the outlet box.
20. The sensor device of claim 15 , wherein the sensor box, the inlet box, and the conduit are made of a photoresist material.