Reduced stress pressure sensor
First Claim
1. A pressure sensor, comprising:
- a first substrate containing layers for CMOS processing,a cap attached to a front side of the first substrate from its front side, wherein the cap includes a container, a holder, and two or more suspension elements to concentrically suspend the holder, wherein the two or more suspension elements are disposed on a back side of the cap for suspending the container from the holder, the container includes a cavity and a polysilicon layer, wherein the cavity is formed on a front side of the container and between the polysilicon layer of the container and a deformable membrane and wherein the cavity is closed by the deformable membrane, wherein the deformable membrane separates the cavity and a port that is positioned on the back side of the cap and is open to an outside of the pressure sensor, the container being suspended form the holder such that the deformable membrane faces the first substrate and such that a gap is provided between the deformable membrane and the first substrate which gap contributes to the port, and wherein the back side of the cap includes a recess formed on a back side of the container, and wherein a permeable protection membrane is disposed on the back side of the cap and covers the recess that is permeable to pressure medium, andsensing means for converting a response of the deformable membrane to pressure at the port into a signal capable of being processed by the processing circuit.
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Accused Products
Abstract
A pressure sensor comprises a first substrate containing a processing circuit integrated thereon and a cap attached to the first substrate. The cap includes a container, a holder, and one or more suspension elements for suspending the container from the holder. The container includes a cavity and a deformable membrane separating the cavity and a port open to an outside of the pressure sensor. The container is suspended from the holder such that the deformable membrane faces the first substrate and such that a gap is provided between the deformable membrane and the first substrate which gap contributes to the port. Sensing means are provided for converting a response of the deformable membrane to pressure at the port into a signal capable of being processed by the processing circuit.
116 Citations
22 Claims
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1. A pressure sensor, comprising:
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a first substrate containing layers for CMOS processing, a cap attached to a front side of the first substrate from its front side, wherein the cap includes a container, a holder, and two or more suspension elements to concentrically suspend the holder, wherein the two or more suspension elements are disposed on a back side of the cap for suspending the container from the holder, the container includes a cavity and a polysilicon layer, wherein the cavity is formed on a front side of the container and between the polysilicon layer of the container and a deformable membrane and wherein the cavity is closed by the deformable membrane, wherein the deformable membrane separates the cavity and a port that is positioned on the back side of the cap and is open to an outside of the pressure sensor, the container being suspended form the holder such that the deformable membrane faces the first substrate and such that a gap is provided between the deformable membrane and the first substrate which gap contributes to the port, and wherein the back side of the cap includes a recess formed on a back side of the container, and wherein a permeable protection membrane is disposed on the back side of the cap and covers the recess that is permeable to pressure medium, and sensing means for converting a response of the deformable membrane to pressure at the port into a signal capable of being processed by the processing circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for manufacturing a pressure sensor comprising:
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providing a first substrate with a processing circuit integrated thereon; providing a second substrate; providing a third substrate; manufacturing a cavity in the second substrate and one or more trenches around a first, portion of the second substrate containing the cavity; mounting said third substrate to said second substrate to form a container, a holder, and two or more suspension elements to concentrically suspend the holder, wherein the two or more suspension elements are disposed on a back side of the second substrate for suspending the container from the holder, and wherein the holder includes the cavity and a polysilicon layer, wherein the cavity is closed on a front side of the container and between the polysilicon layer of the container and further closed by a deformable membrane, wherein the deformable membrane is configured for sensing a pressure applied to the deformable membrane, wherein the deformable membrane separates the cavity and a port that is positioned on the back side of the second substrate and is open to an, outside of the pressure sensor, and wherein a permeable protection membrane that is permeable to pressure is disposed on the back side of the second substrate and covers a recess formed on a back side of the container; and mounting the assembly of the second substrate and the third substrate to the first substrate with the deformable membrane facing the first substrate and providing a gap between the deformable membrane and the first substrate wherein the deformable membrane faces the first substrate and wherein the gap contributes to the port. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification