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PRESSURE SENSOR

IP.com Disclosure Number: IPCOM000235858D
Publication Date: 2014-Mar-27

Publishing Venue

The IP.com Prior Art Database

Abstract

A pressure sensor comprises a first substrate (1) and a cap (4) attached to the first substrate (1). The cap (4) includes a processing circuit (241), a cavity (41) and a deformable membrane (42) separating the cavity (41) and a port open to an outside of the pressure sensor. Sensing means are provided for converting a response of the deformable membrane (42) to pressure at the port into a signal capable of being processed by the processing circuit (241). The cap (4) is attached to the first substrate (1) such that the deformable membrane (42) faces the first substrate (1) and such that a gap (6) is provided between the deformable membrane (42) and the first substrate (1) which gap (6) contributes to the port. The first substrate (1) comprises a support portion (7) the cap (4) is attached to, a contact portion (8) for electrically connecting the pressure sensor to an external device, and one or more suspension elements (9) for suspending the support portion (7) from the contact portion (8).

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Page 01 of 23

PRESSURE SENSOR

ABSTRACT

          A pressure sensor comprises a first substrate (1)
and a cap (4) attached to the first substrate (1). The cap (4)
includes a processing circuit (241), a cavity (41) and a de-
formable membrane (42) separating the cavity (41) and a port
open to an outside of the pressure sensor. Sensing means are
provided for converting a response of the deformable membrane
(42) to pressure at the port into a signal capable of being
processed by the processing circuit (241). The cap (4) is at-
tached to the first substrate (1) such that the deformable
membrane (42) faces the first substrate (1) and such that a
gap (6) is provided between the deformable membrane (42) and
the first substrate (1) which gap (6) contributes to the port.
The first substrate (1) comprises a support portion (7) the
cap (4) is attached to, a contact portion (8) for electrically
connecting the pressure sensor to an external device, and one
or more suspension elements (9) for suspending the support
portion (7) from the contact portion (8).

FIELD OF THE INVENTION

          The present invention relates to a pressure sensor
and a method for manufacturing a pressure sensor.

BACKGROUND OF THE INVENTION

          Pressure sensors and methods of manufacturing pres-
sure sensors are known. In pressure sensors the membrane may
be sensitive to stress. When a pressure sensor is mounted to a
carrier and is electrically connected thereto mechanical
stress may be evoked and transmitted via solder balls to the
first substrate and specifically to stress sensitive struc-
tures of the pressure sensor such as the membrane.

SUMMARY OF THE INVENTION


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          Hence, according to a first aspect of the inven-
tion, there is provided a pressure sensor, particularly an ab-
solute pressure sensor, with a deformable membrane providing a
separation between a cavity with in the case of an absolute
pressure sensor an essentially constant pressure and a port
open to the outside of the sensor. The cavity is formed in a
cap which cap is attached to a first substrate such that the
deformable membrane faces the first substrate and such that a
gap is provided between the deformable membrane and the first
substrate. The cap further contains a processing circuit. A
deformation of the deformable membrane is converted by suita-
ble sensing means into a signal that is supplied to and pro-
cessed by the processing circuit in the cap.

          The first substrate contains a support portion to
which the cap is attached. A contact portion of the first sub-
strate is provided for electrically connecting the pressure
sensor to the outside world. The support portion is suspended
from the contact portion by one or more suspension elements.

          In this arrangement, the deformable membrane as el-
ement sensitive to stress in essence is mechanically decoupled
from the contact portion of the first substrate via which
stress may be induced from an external carrier, or during
mounting of the pressure sensor to an external carrier given
that the contact portion preferably is...