阅读说明：本技术 用于低密度材料的芯片级感测装置 (Chip-scale sensing device for low-density materials ) 是由 J·C·巴特 J·C·程 R·I·奥尔森 于 2019-01-22 设计创作，主要内容包括：一种针对各种应用的在芯片级上高效地且经济地生产的电化学传感器装置被公开。在一些方面,所述装置是在晶圆技术上或者使用晶圆技术制作的,由此传感器室是通过所述晶圆创建的,并且气体端口允许传感器的工作电极检测某些气体。通过使用晶圆技术,大规模生产是可能的,其中单个传感器是从一个或更多个共用晶圆生产的。集成电路在晶圆中或晶圆上被以集成的方式制作以使得晶圆为集成电路系统和互连部分提供基板、而且还提供其中设置气体传感器的室的限定。(An electrochemical sensor device efficiently and economically produced on a chip scale for various applications is disclosed. In some aspects, the device is fabricated on or using wafer technology, whereby a sensor chamber is created through the wafer, and the gas port allows the working electrode of the sensor to detect certain gases. By using wafer technology, mass production is possible, where individual sensors are produced from one or more common wafers. Integrated circuits are fabricated in or on a wafer in an integrated manner such that the wafer provides a substrate for integrated circuit systems and interconnects, but also provides a definition of a chamber in which the gas sensor is disposed.)

1. A chip-scale electrochemical sensing device, the chip-scale electrochemical sensing device comprising:

a base wafer having an outwardly facing side and an inwardly facing side, the inwardly facing side partially defining a sensor chamber, the base wafer further having a plurality of vias passing through the base wafer and extending between the inwardly and outwardly facing sides of the base wafer;

at a first of the through holes, including a gas port allowing gas communication between the outwardly facing side and the inwardly facing side of the substrate wafer, and in particular allowing gas on the outwardly facing side of the substrate wafer to pass through the gas port through hole into the sensor chamber;

an electrochemical sensor responsive to a property of the gas, disposed in the sensor chamber;

the electrochemical sensor comprises a first electrode and a second electrode, wherein the first electrode and the second electrode are coupled by an electrolyte, and wherein the first electrode is exposed to the gas entering the sensor chamber through the gas port;

a second of the vias comprises a conductive via electrically coupling the first electrode of the electrochemical sensor to a first electrical contact on the outward-facing side of the base wafer;

a third one of the vias comprises a conductive via electrically coupling the second electrode of the electrochemical sensor to a second electrical contact on an outward-facing side of the base wafer;

at least one electrical connection set that carries electrical signals to and from the device; and

an integrated circuit fabricated on or in any of the base and cap wafers, the integrated circuit being electrically coupled to the set of electrical connections.

2. The device of claim 1, further comprising a device package comprising the electrochemical sensor and the integrated circuit.

3. The apparatus of claim 1, the sensor chamber defined at least in part by a recess in the inward-facing side of the wafer.

4. The apparatus of claim 1, the sensor chamber defined at least in part by a cap wafer disposed over the inward-facing side of the base wafer.

5. The apparatus of claim 4, the cap wafer having a recess therein that partially defines the sensor chamber.

6. The apparatus of claim 4, the cap wafer comprising any one of: wafer level semiconductive panels, die level panels, glass panels, ceramic panels, polymer panels, and Printed Circuit Board (PCB) panels.

7. The apparatus of claim 1, wherein the first and second electrodes are disposed between the electrolyte and the inward-facing side of the base wafer.

8. The apparatus of claim 1, further comprising a gas seal disposed vertically between the electrolyte and the inward facing side of the base wafer, the gas isolating one portion of the sensor chamber from another portion, the gas seal also disposed laterally around the first electrode and the gas port.

9. The device of claim 1, further comprising a gas permeable filter that filters gas passing through the gas port.

10. The device of claim 9, said filter being size selective in its permeability.

11. The apparatus of claim 9, the filter comprising at least one of a hydrophobic material and an oleophobic material.

12. The device of claim 9, the filter comprising a sealed sidewall.

13. The device of claim 1, the first and second electrical contacts comprising soldering protrusions that electrically couple the sensor device to external circuitry in a system that includes the sensor device.

14. The apparatus of claim 4, any one of the base wafer and the cap wafer comprising a silicon wafer.

15. The apparatus of claim 4, any one of the base wafer and the cap wafer comprising a ceramic wafer.

16. The device of claim 4, any one of the base wafer and the cap wafer comprising a Printed Circuit Board (PCB).

17. An article of manufacture, comprising:

a common base wafer and a common cap wafer into which one or more integrated circuits are packaged and onto which a plurality of electrochemical sensor devices are created;

each of the plurality of sensor devices comprises a plurality of electrodes disposed within a respective sensor chamber defined at least in part by the base wafer and the cap wafer and a sidewall separating the cap wafer and the base wafer;

each of the plurality of sensor devices further comprises an electrolyte material contacting each of the respective plurality of sensor electrodes of the sensor device; and is

Wherein at least one sensor electrode of each sensor device comprises a working electrode in gaseous communication with an external environment of the device through a respective gas port through-hole in one of the substrate wafer and the cap wafer to provide gas coupling between the working electrode and the external environment while being gas isolated from other electrodes within the same sensor device by a gas seal.

18. The article of claim 17, the sidewall comprising different separator wafers or plates that separate the thickness of the separator wafers or plates from the base wafer and the cap wafer.

19. The article of claim 17, the sidewalls monolithically formed from at least one of the base wafer and the cap wafer.

20. The article of claim 17, wherein at least one multi-sensor device is formed from the common wafer, the at least one multi-sensor device having a plurality of electrochemical sensor devices of its own.

21. The article of manufacture of claim 20, said multi-sensor device being configured and arranged to detect a plurality of different gases, each of said electrochemical sensor devices of said multi-sensor device detecting one such different gas in said multi-sensor device.

22. A method for fabricating a chip scale electrochemical sensor device, the method comprising:

forming a plurality of wafers comprising a base wafer and a cap wafer, each of the cap wafer and the base wafer having an inward facing side and an outward facing side;

forming through holes in one or more of the cap wafer and the base wafer, the through holes including at least one gas port through hole that allows movement of gas from outside the device to an interior space therein;

forming a plurality of electrochemical sensor electrodes comprising a working electrode in a sensor chamber defined by the cap wafer and the base wafer, the working electrode disposed in a portion of the sensor chamber in gaseous communication with an exterior of the device through the gas port via;

placing an electrolyte in contact with each of the plurality of sensor electrodes within the sensor chamber;

isolating a volume within the sensor chamber including the working electrode to prevent or reduce gas movement between the portion of the sensor chamber containing the working electrode and other portions of the sensor chamber; and

electrical connections are made in the cap wafer and the base wafer to electrically connect the plurality of electrodes to each other or to external connection points.

23. The method of claim 22, wherein a plurality of sensor devices are created from the cap wafer and the base wafer in parallel, and further comprising singulating the cap wafer and the base wafer for a plurality of different individual sensor devices.

24. The method of claim 22, further comprising dicing the cap wafer and the base wafer and associated electrochemical sensors to form at least one multi-sensor device having a plurality of electrochemical sensors therein.

25. The method of claim 22, further comprising integrating an integrated circuit into any of the cap wafer and the base wafer, the integrated circuit being electrically coupled to the external connection point.

26. A chip scale gas sensor, the chip scale gas sensor comprising:

a cap wafer;

a base wafer;

a spacer wafer disposed between the cap wafer and the base wafer and defining a sensor chamber with the cap wafer and the base wafer;

a solid or semi-solid electrolyte within the sensor chamber;

a plurality of sensor electrodes within the sensor chamber, each of the sensor electrodes in contact with the solid or semi-solid electrolyte;

a gas port via in any one of the cap wafer and the base wafer;

a gas barrier liner coupled to the electrolyte; and

an Application Specific Integrated Circuit (ASIC) integrated into any of the cap wafer or base wafer.

27. The sensor of claim 26, further comprising a gas filter that filters gas moving within the gas port through-hole.

Technical Field

The present invention relates to the design and manufacture of sensor devices that sense or identify low density materials (e.g., gases) through electrochemical cells integrated with sensing circuitry in chip scale packages.

Background

Given the changes in the earth's atmosphere due to industrialized and natural resources, as well as the drastically increasing number of sources of household and urban pollution, the need for accurate and continuous air quality monitoring has become a necessary condition for determining sources and alerting consumers to impending dangers. Making real-time monitoring and exposure assessment practical is the ability to provide low cost, small form factor and low power devices that can be integrated into the broadest range of platforms and applications.

There are a number of ways to sense different low density materials, such as gases. Common methods include non-dispersive infrared spectroscopy (NDIR), the use of metal oxide sensors, the use of chemiresistors, and the use of electrochemical sensors. The present invention relates to electrochemical sensors.

One drawback of conventional electrochemical sensors is that their size (e.g., the volume of the electrolyte and the size of the electrodes) is relatively large, such that it takes a long time to settle when subjected to the target gas. Furthermore, the signal-to-noise ratio is low because the change in current in response to the gas is small, and there are losses and RF coupling due to metal traces to processing circuitry outside the sensor, which further reduces the signal-to-noise ratio. In addition, the electrochemical cell body is typically a polymer that cannot withstand temperatures above 150 ℃, and the electrolyte comprises an aqueous solution of an acid that cannot withstand temperatures above about 100 ℃. This prevents the electrical contacts from being soldered to the printed circuit board by reflowing the solder (typically at 180-260 c) and prevents the use of some thermosetting conductive adhesives (such as silver-containing epoxy, or anisotropic conductive films or pastes) that are typically cured at 120-150 c.

There are a number of ways to sense different low density materials, such as gases. Common methods include non-dispersive infrared spectroscopy (NDIR), the use of metal oxide sensors, the use of chemiresistors, and the use of electrochemical sensors. Some electrochemical sensors are also known to those skilled in the art. In this application we describe further miniaturization of such integrated electrochemical systems by applying wafer-level packaging, panel-level packaging and chip-level packaging technologies.

The present disclosure provides several designs, features, novel devices and methods for making and using the same.

SUMMARY

The following description and the annexed drawings set forth in detail certain illustrative implementations of the disclosure, which are indicative of several exemplary ways in which the various principles of the disclosure may be carried out. However, the illustrative examples are not exhaustive of the many possible embodiments of the disclosure. Other objects, advantages and novel features of the disclosure will be set forth in the following detailed description of the disclosure when considered in conjunction with the drawings.

One or more embodiments are directed to a chip-scale electrochemical sensing device, comprising: a base wafer having an outwardly facing side and an inwardly facing side, the inwardly facing side partially defining a sensor chamber, the base wafer further having a plurality of vias extending therethrough and between the inwardly and outwardly facing sides thereof; at a first of the through holes, a gas port is included that allows gas communication between the outwardly facing side and the inwardly facing side of the substrate wafer, in particular allows gas on the outwardly facing side of the substrate wafer to pass through the gas port through hole into the sensor chamber; an electrochemical sensor responsive to a property of the gas, disposed in the sensor chamber; the electrochemical sensor comprises a first electrode and a second electrode, wherein the first electrode and the second electrode are coupled by an electrolyte, and wherein the first electrode is exposed to the gas entering the sensor chamber through the gas port; a second of the vias comprises a conductive via electrically coupling the first electrode of an electrochemical sensor to a first electrical contact on an outward-facing side of the base wafer; a third one of the vias comprises a conductive via electrically coupling the second electrode of an electrochemical sensor to a second electrical contact on an outward-facing side of the base wafer; and at least one electrical connection set for carrying electrical signals to and from the device; and an integrated circuit fabricated on or in any of the base wafer and the cap wafer, the integrated circuit being electrically coupled to the set of electrical connections.

Other embodiments are directed to an article of manufacture comprising: a common base wafer and a common cap wafer into which a plurality of integrated circuits are packaged and onto which a plurality of electrochemical sensor devices are created; each of the plurality of sensor devices comprises a plurality of electrodes disposed within a respective sensor chamber defined at least in part by a base wafer and a cap wafer and a sidewall separating the cap wafer and the base wafer; each of the plurality of sensor devices further comprises an electrolyte material contacting each of the respective plurality of sensor electrodes of the sensor device; and wherein at least one sensor electrode of each sensor device comprises a working electrode in gaseous communication with the external environment of the device through a respective gas port through-hole in one of the substrate wafer and the cap wafer, so as to provide gaseous coupling between the working electrode and the external environment while being gas isolated from other electrodes within the same sensor device.

Yet another embodiment is directed to a method for fabricating a chip-scale electrochemical sensor device, the method comprising: forming a plurality of wafers including a base wafer and a cap wafer, each of the cap wafer and the base wafer having an inward facing side and an outward facing side; forming through holes in one or more of the cap wafer and the base wafer, including at least one gas port through hole that allows movement of gas from outside the device to an interior space therein; forming a plurality of electrochemical sensor electrodes comprising a working electrode in a sensor chamber defined by the cap wafer and the base wafer, the working electrode being disposed in a portion of the sensor chamber in gaseous communication with an exterior of the device through the gas port via; placing an electrolyte in contact with each of the plurality of sensor electrodes within the sensor chamber; isolating a volume within the sensor chamber including the working electrode to prevent or reduce gas movement between the portion of the sensor chamber containing the working electrode and other portions of the sensor chamber; and forming electrical connections in the cap wafer and the base wafer to electrically connect the plurality of electrodes to each other and to external connection points.

Still other embodiments are directed to a chip-scale gas sensor, comprising: a cap wafer; a base wafer; a spacer wafer disposed between the cap wafer and the base wafer and defining a sensor chamber with the cap wafer and the base wafer; a solid or semi-solid electrolyte within the sensor chamber; a plurality of sensor electrodes within the sensor chamber, each of the sensor electrodes in contact with a solid or semi-solid electrolyte; a gas port via in any one of the cap wafer and the base wafer; a gas barrier liner coupled to the electrolyte; and an Application Specific Integrated Circuit (ASIC) integrated into any of the cap wafer or base wafer. The gas port through-hole may have a gas filter applied thereto that filters, blocks, or otherwise affects the gas moving through the gas port.

Accordingly, in various aspects, electrochemical sensor devices are disclosed that are efficiently and economically produced on a chip scale for various applications. In some aspects, the device is fabricated on or using wafer technology, whereby the sensor chamber is created through the wafer, and the gas port allows the working electrode of the sensor to detect certain gases. By using wafer technology, mass production is possible, where individual sensors are produced from one or more common wafers. Integrated circuits are fabricated in or on a wafer in an integrated manner such that the wafer provides a substrate for integrated circuit systems and interconnects, but also provides a definition of a chamber in which the gas sensor is disposed.