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Chemical sensor and method for manufacturing such a chemical sensor

IP.com Disclosure Number: IPCOM000227914D
Publication Date: 2013-May-29

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention relates to a chemical sensor (1) comprising a substrate layer (2) having a front surface (2.1) and a back surface (2.2) and a sensing layer (3) arranged on the front surface (2.1) of the substrate layer (2), the sensing layer (3) comprising a sensing element (4) and the substrate layer (2) being provided with a well (5) in the back surface (2.2) to a form a membrane (6) that incorporates the sensing element (4), wherein the substrate layer (2) is provided with contact pads (10) on the back surface (2.2) and with vias (11) extending from the front surface (2.1) to the back surface (2.2) for electrically connecting the sensing element (4) with the contact pads (10), wherein a handling layer (17) is provided on top of the sensing layer (3), the handling layer (17) surrounding the sensing element (4), and wherein the thickness (d1) of the handling layer (17) is larger than the thickness (d2) of the substrate layer (2). The invention furthermore relates to a method for manufacturing such a chemical sensor (1).

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          Chemical sensor and method for manufacturing such a chemical sensor

Abstract

The invention relates to a chemical sensor


(1) comprising a substrate layer (2) having a front sur- face (2.1) and a back surface (2.2) and a sensing layer


(3) arranged on the front surface (2.1) of the substrate layer (2), the sensing layer (3) comprising a sensing el- ement (4) and the substrate layer (2) being provided with a well (5) in the back surface (2.2) to a form a membrane


(6) that incorporates the sensing element (4), wherein the substrate layer (2) is provided with contact pads


(10) on the back surface (2.2) and with vias (11) extend- ing from the front surface (2.1) to the back surface


(2.2) for electrically connecting the sensing element (4) with the contact pads (10), wherein a handling layer (17) is provided on top of the sensing layer (3), the handling layer (17) surrounding the sensing element (4), and wherein the thickness (d1) of the handling layer (17) is larger than the thickness (d2) of the substrate layer


(2). The invention furthermore relates to a method for manufacturing such a chemical sensor (1).

Technical Field

          The invention relates to a chemical sensor and a method for manufacturing such a chemical sensor as described herein. The chemical sensor may in particular be a gas sensor.

Background Art


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          Chemical sensors as disclosed, for example, in GB 2 464 016 B comprise a semiconductor substrate with a front surface and a back surface. A sensing element is formed on the front surface that is provided with a gas- sensitive layer and a heater for heating the gas- sensitive layer to promote gas reaction with the gas- sensitive layer. The gas-sensitive layer is located be- tween electrodes for providing an electrical output in- dicative of the gas reaction with the gas-sensitive lay- er. A well is formed in the back surface of the substrate layer to leave a membrane that incorporates the sensing element. Such chemical sensors can be employed for meas- uring a property of a fluid - and thereby an analyte that forms part of the fluid - that the chemical sensor is ex- posed to through an opening/a port in the housing of a portable electronic device such as for example a smart phone. Such a property may for example be the amount of carbon dioxide or ozone in the ambient air. A fluid may be a gas or a liquid.

          To connect such a chemical sensor to an elec- tric circuit board for further processing of the electri- cal output of the sensing element, with the sensing ele- ment exposable to a fluid to be analysed, typically bond wires are employed electrically connecting the electrodes of the sensing element to contact pads on the electric circuit board. The bond wires are usually enclosed by a pourable compound in form of respective glob-tops for protection. However, the glob-tops require space, space being rare especially in portable electronic devices such as smart phones. Furthermore, the provision of the glob- tops might imp...