News Column

"Sensor Chip and Method for Manufacturing a Sensor Chip" in Patent Application Approval Process

July 3, 2014



By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors HUMMEL, Rene (Baar, CH); STEINER-VANHA, Ralph (Hombrechtikon, CH); BARTSCH, Ulrich (Zurich, CH), filed on December 6, 2013, was made available online on June 19, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application has not been assigned to a company or institution.

The following quote was obtained by the news editors from the background information supplied by the inventors: "The present invention relates to a sensor chip and a method for manufacturing a sensor chip.

"Integrated fabrication techniques such as, for example, CMOS processing may be applied not only to manufacture electronic circuits but also to manufacture sensors, also denoted as sensor chips in the following. In such sensor chips, a sensor structure may be built in or on a substrate, such as a semiconductor substrate, and may or may not be integrated with associated electronic circuitry on the same chip.

"In EP 1 236 038 B1, a capacitive sensor chip is disclosed containing multiple electrode elements structured on an oxide layer covering a substrate. The electrode elements are covered by insulating material which subsequently is etched. However, while the electrode elements may serve as an etch stop to the etching process, etching the insulating material in gaps between the electrode elements may only be controllable by defining the etching time upfront. This may result in varying depths etched into the insulating material. It was observed that the resulting etch depth may vary across a wafer e.g. with deeper etching results in the centre of the wafer than at its periphery. It was also observed that the resulting etch depth may vary from wafer to wafer.

"In particular, when the gaps between the electrode elements will be filled by a measuring material acting, for example, as a dielectric layer between the respective electrode elements for capacitive measurements, a varying volume of the measuring material may impact the measurement results which effect may only be compensated by increased efforts in calibrating such sensor chips."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "According to a first aspect of the present invention a sensor chip is provided comprising a substrate, a plurality of electrode elements arranged at a first level on the substrate, at least one gap between neighbouring electrode elements, a metal structure arranged at a second level on the substrate, wherein the second level is different from the first level, wherein the metal structure at least extends over an area of the second level that is defined by a projection of the at least one gap towards the second level.

"Preferred embodiments of the sensor chip may contain one or more of the following features:

"the second level is arranged between the substrate and the first level;

"the at least one gap is at least partly filled with a dielectric material of a measuring layer for building a capacitive sensor;

"at least n electrode elements and n-1 gaps with n>2, wherein the n electrode elements represent n electrode fingers of at least one electrode structure, and in particular wherein the n electrode elements represent n electrode fingers of two interdigitating electrode structures;

"the metal structure comprises multiple metal elements, and each metal element is assigned to one of the gaps for extending over an area of the second level that is defined by a projection of the assigned gap towards the second level;

"each gap comprises at least an area in the first level confined by neighbouring electrode elements;

"multiple of the electrode elements are arranged in parallel, and the at least one gap has the form of a rectangle;

"the metal structure includes a single metal layer extending underneath each gap and the electrode elements;

"at least part of the metal structure is used as an electrode structure for interacting with one or more of the electrode elements;

"a protection layer covers the electrode elements and at least part of the metal structure, and comprises a measuring layer covering the protection layer;

"the metal structure includes a shape complementary to a shape of the electrode elements in an area within outer electrode elements.

"According to another aspect of the present invention, a method is provided for manufacturing a sensor chip, the sensor chip comprising a plurality of electrode elements arranged at a first level on a substrate, at least one gap between neighbouring electrode elements, and a metal structure arranged at a second level on the substrate, wherein the second level is different from the first level, and wherein the metal structure at least extends over an area of the second level that is defined by a projection of the at least one gap towards the second level, the method comprising the step of etching an insulating material covering the electrode elements and at least part of the metal structure and using the electrode elements and at least part of the metal structure as an etch stop.

"Preferred embodiments of the method may contain one or more of the following features: the insulating material is etched by means of an etchant applied for a predefined time; a protection layer is applied to the electrode elements and at least the part of the metal structure, and a measuring layer is applied on top of the protection layer; prior to etching the insulating material a first insulating layer is applied on the substrate and a first metal layer is applied to a layer stack comprising at least the first insulating layer and the substrate; the first metal layer is applied for building the metal structure, a second insulating layer is applied to the structured first metal layer, a second metal layer is applied to the second insulating layer, the second metal layer is structured for building the electrode elements, a third insulating layer is applied to the structured second metal layer, and the etching step is applied.

"Other advantageous embodiments are listed in the dependent claims as well as in the description below.

"The described embodiments similarly pertain to the sensor chip and the method. Synergetic effects may arise from different combinations of the embodiments although they might not be described in detail.

BRIEF DESCRIPTION OF THE DRAWINGS

"The aspects defined above and further aspects, embodiments and advantages of the present invention can also be derived from the examples of embodiments to be described hereinafter with reference to the drawings. In the drawings, the figures show:

"FIG. 1 a cross section of a sensor chip according to an embodiment of the present invention,

"FIG. 2 in diagrams (a) to (f) various stages in the manufacturing of a sensor chip in a cross sectional view according to an embodiment of the present invention,

"FIG. 3 a top view on the sensor chip as illustrated in FIG. 2(f), and

"FIG. 4 a top view on the sensor chip as illustrated in FIG. 2(f) with a different design of the metal structure, and

"FIG. 5 a cross section of a sensor chip according to another embodiment of the present invention."

URL and more information on this patent application, see: HUMMEL, Rene; STEINER-VANHA, Ralph; BARTSCH, Ulrich. Sensor Chip and Method for Manufacturing a Sensor Chip. Filed December 6, 2013 and posted June 19, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=5505&p=111&f=G&l=50&d=PG01&S1=20140612.PD.&OS=PD/20140612&RS=PD/20140612

Keywords for this news article include: Patents.

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Source: Politics & Government Week


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