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PRESSURE SENSOR

IP.com Disclosure Number: IPCOM000235856D
Publication Date: 2014-Mar-27

Publishing Venue

The IP.com Prior Art Database

Abstract

A pressure sensor comprises a first substrate (1) containing a processing circuit integrated thereon and a cap (4) attached to the first substrate (1). The cap (4) includes a container (41), a holder (42), and one or more suspension elements (45) for suspending the container (41) from the holder (42). The container (41) includes a cavity (411) and a deformable membrane (412) separating the cavity (411) and a port open to an outside of the pressure sensor. The container (41) is suspended from the holder (42) such that the deformable membrane (412) faces the first substrate (1) and such that a gap (6) is provided between the deformable membrane (412) and the first substrate (1) which gap (6) contributes to the port. Sensing means (116) are provided for converting a response of the deformable membrane (412) to pressure at the port into a signal capable of being processed by the processing circuit.

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Page 01 of 23

PRESSURE SENSOR

ABSTRACT

          A pressure sensor comprises a first substrate (1)
containing a processing circuit integrated thereon and a cap
(4) attached to the first substrate (1). The cap (4) includes
a container (41), a holder (42), and one or more suspension
elements (45) for suspending the container (41) from the hold-
er (42). The container (41) includes a cavity (411) and a de-
formable membrane (412) separating the cavity (411) and a port
open to an outside of the pressure sensor. The container (41)
is suspended from the holder (42) such that the deformable
membrane (412) faces the first substrate (1) and such that a
gap (6) is provided between the deformable membrane (412) and
the first substrate (1) which gap (6) contributes to the port.
Sensing means (116) are provided for converting a response of
the deformable membrane (412) to pressure at the port into a
signal capable of being processed by the processing circuit.

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 with
its back side 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 structures of the pressure sensor such as the mem-
brane.

SUMMARY OF THE INVENTION


Page 02 of 23

          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
container contributing to a cap which cap is attached to a
first substrate with a processing circuit integrated thereon.
The cap further contains a holder for the container. The con-
tainer is suspended from the holder by means of one or more
suspension elements. The container further contains the de-
formable membrane a deformation of which is converted by suit-
able sensing means into a signal that is supplied to and pro-
cessed by the processing circuit in the first substrate.

          In this arrangement, the deformable membrane in es-
sence is mechanically decoupled from the first substrate via
which first substrate stress may be induced from an external
carrier of the pressure sensor, or during mounting of the
pressure sensor to an external carrier. Not only is the de-
formable membrane no longer attached to the first substrate
containing the processing circuit but is integrated into the
cap. Moreover, the membrane is also mechanically decoupled
within the cap from the cap portion that is mounted to the
first substrate, i.e. the holder. Hence, any propagation of
stress induced via the first substrate towa...