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Sensor chip

IP.com Disclosure Number: IPCOM000238990D
Publication Date: 2014-Sep-30

Publishing Venue

The IP.com Prior Art Database

Abstract

A sensor chip comprises a substrate with a front side and a back side, and an opening in the substrate reaching through from its back side to its front side. A stack of dielectric and conducting layers is arranged on the front side of the substrate, a portion of which stack spans the opening of the substrate. Contact pads are arranged at the front side of the substrate for electrically contacting the sensor chip. A sensing element is arranged on the portion of the stack spanning the opening on a side of the portion facing the opening.

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SENSOR CHIP

Technical Field

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

Abstract

          A sensor chip comprises a substrate (1) with a
front side (11) and a back side (12), and an opening (13) in
the substrate (1) reaching through from its back side (12) to
its front side (11). A stack (2) of dielectric and conducting
layers is arranged on the front side (11) of the substrate
(1), a portion of which stack (2) spans the opening (13) of
the substrate (1). Contact pads (32) are arranged at the front
side (11) of the substrate (1) for electrically contacting the
sensor chip. A sensing element (4) is arranged on the portion
of the stack (2) spanning the opening (13) on a side of the
portion facing the opening (13).

Background Art

          Subject to the application, sensors tend to be in-
tegrated on semiconductor substrates. This kind of manufactur-
ing is beneficial in that the size of the sensors can signifi-
cantly be reduced compared to discrete type sensors, and such
sensors can be arranged together with electronic circuitry in-
tegrated on the same semiconductor substrate which circuitry
may include functions acting on a signal delivered by the sen-
sor such as amplification, evaluation, etc.

          An integrated chip comprising a sensor is called
sensor chip in the following. In such sensor chip, the sensor
and possibly electronic circuitry are arranged at a front side
of a substrate. The circuitry may be formed by CMOS pro-
cessing, and the building and/or arranging of a sensing ele-
ment of the sensor on the front side may be implemented in a
way compatible to CMOS processing. When such sensor chip needs
to be integrated into a processing system, the sensor chip


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typically will be connected to circuitry residing on a differ-
ent circuit board, such as a printed circuit board, for exam-
ple. A preferred way for mounting a sensor chip to such cir-
cuit board is a technique called flip chip mounting in which
the sensor chip is flipped such that its front side containing
the sensing element and the circuitry faces the circuit board
and is electrically connected to it. The electrical connection
typically is achieved between contact pads arranged at the
front side of the sensor chip and contact pads arranged on the
circuit board and solder material in between.

          However, now the sensing element faces the circuit
board which may not be preferred for various reasons: In case
the sensor shall detect a quantity of a measure in a medium in
the environment of the sensor, such medium may not have suffi-
cient access to the sensing element for the reason of its ar-
rangement facing the circuit board. In addition, and even
worse, the sensing element may be affected during handling,
and specifically when mounting / soldering the sensor chip to
the circuit board, e.g. when applying a solder forming flux.

Disclosure of the Invention

          The problem to be solved by the present invention
is therefore to provide a sensor chip wherein the sensor ele-
ment...