Pressure sensor element and method of manufacturing the same
A pressure sensor element includes a die; a cavity and a trench formed in one surface of the die and defining therebetween a partition wall integral with and formed of the same material as the die; and a membrane formed on the die and covering the cavity and the trench.
1. A pressure sensor element comprising:
a die;
a cavity and a trench formed in one surface of the die and defining therebetween a partition wall configured to buffer an effect of deformation of the trench on the cavity; and
a membrane formed on the die and covering the cavity and the trench,
wherein the membrane includes at least one deformable sensor, overlaying the cavity, configured to measure a pressure applied to the membrane overlaying the cavity.
2. The pressure sensor element of claim 1 , wherein the trench and the partition wall encircle the cavity.
3. The pressure sensor element of claim 1 , wherein the membrane is fixed integrally with an upper surface of the partition wall.
4. The pressure sensor element of claim 1 , wherein the membrane includes a sensing membrane part formed in a region overlying the cavity, and an external force blocking membrane part formed in a region overlying the trench.
5. The pressure sensor element of claim 4 ,
wherein the at least one deformable sensor is formed on the sensing membrane part, and
wherein a wiring pattern is formed on the die and the membrane, the wiring pattern being electrically connected to the at least one deformable sensor.
6. A pressure sensor element comprising:
a die;
a cavity and a trench formed in one surface of the die and defining therebetween a partition wall; and
a membrane formed on the die and covering the cavity and the trench,
wherein the membrane includes
a sensing membrane part, formed in a region overlying the cavity, configured with one or more pressure sensors to sense force applied to the sensing membrane part, and
an external force blocking membrane part, formed in a region overlying the trench, configured without a pressure sensor.
7. The pressure sensor element of claim 6 , wherein the one or more pressures sensors are formed on the sensing membrane part.
8. The pressure sensor element of claim 7 , wherein a wiring pattern is formed on the die and the membrane, and
the wiring pattern is electrically connected to the one or more pressure sensors.
9. A method of manufacturing a pressure sensor element, comprising:
forming a trench and a cavity in a die, the trench and the cavity defining therebetween a partition wall configured to buffer an effect of elastic deformation of the trench on the cavity; and
forming a membrane covering the trench and the cavity; and
forming at least one deformable sensor, overlaying the cavity, configured to measure a pressure applied to the membrane covering the cavity.
10. The method of claim 9 , wherein the forming of the trench and the cavity in the die includes etching the die using a mask on which a slit pattern corresponding to the trench and the cavity is formed.
11. The method of claim 9 , wherein the forming of the membrane includes:
bonding a substrate for a membrane to the die in which the trench and the cavity are formed; and
polishing the substrate for a membrane to form the membrane having a predetermined thickness.
12. The method of claim 9 , wherein the trench and the partition wall encircle the cavity.
13. The method of claim 9 , wherein the forming of the membrane includes forming a sensing membrane part formed in a region overlying the cavity and an external force blocking membrane part formed in a region overlying the trench.
14. The method of claim 13 ,
wherein the forming of the at least one deformable sensor includes forming the at least one deformable sensor on the sensing membrane part, and
the method further comprises forming a wiring pattern, on the die and the membrane, electrically connected to the at least one deformable sensor.
15. A method of manufacturing a pressure sensor element, comprising:
forming a trench and a cavity in a die, the trench and the cavity defining therebetween a partition wall; and
forming a membrane covering the trench and the cavity,
wherein the forming of the trench and the cavity in the die includes:
n-doping a lattice shaped region corresponding to the trench and a lattice shaped region corresponding to the cavity on a surface of the die;
porous-etching the die below the n-doped lattice shaped regions; and
forming hollows in the die below the n-doped lattice shaped regions.
16. The method of claim 15 , wherein the forming of the membrane includes growing an epitaxial layer on the n-doped lattice shaped regions to form the membrane.
17. The method of claim 15 , wherein the hollows are formed through chemical treatment or through heat treatment.
18. A pressure sensor apparatus comprising:
a substrate;
a die coupled to at least a portion of the substrate and having a planar cavity and a trench formed therein, the trench and the cavity defining therebetween a partition wall;
at least one force attenuating region disposed around a peripheral portion of the planar cavity; and,
a flexible membrane covering the planar cavity and including at least one deformable sensor disposed on the flexible membrane configured to measure a pressure applied to the membrane.
19. The apparatus of claim 18 , wherein the deformable sensor comprises a piezoresistor.
20. The apparatus of claim 19 , wherein the deformable sensor comprises a plurality of piezoresistors coupled in a voltage divider circuit.
21. The apparatus of claim 19 , wherein the deformable sensor comprises a plurality of piezoresistors coupled in a Wheatstone circuit.
22. The apparatus of claim 21 , wherein the force attenuating region comprises the trench and the partition wall, both of which encircle the planar cavity.
23. The apparatus of claim 22 , wherein the deformable die is coupled to the substrate with an adhesive layer adaptively formed to isolate deformations of the substrate from the die.
24. The apparatus of claim 18 , wherein the flexible membrane also covers the trench.