CHEMICAL SENSOR WITH CONDUCTIVE CUP-SHAPED SENSOR SURFACE
A system includes a sensor including a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. The system further includes a conductive layer disposed over the lower surface and the wall surface.
This application is a continuation of U.S. patent application Ser. No. 14/260,818 filed Apr. 24, 2014, which is a continuation of U.S. patent application Ser. No. 13/354,108 filed Jan. 19, 2012, the entire contents of which are incorporated by reference herein in their entirety.
FIELD OF THE INVENTIONThis disclosure, in general, relates to sensor arrays and methods for making same.
BACKGROUNDElectronic sensor arrays are finding increased use for detecting analytes in fluids, such as gases or liquids. In particular, arrays of sensors based on field effect transistors are finding use in detecting ionic components, such as various cations, anions or pH. Such sensors are often referred to as ion-sensitive field effect transistors or ISFETs.
Recently, such sensor arrays have found use in sequencing polynucleotides. Nucleotide addition results in the release of ionic species that influence the pH in a local environment. Sensors of the sensor arrays are used to detect changes in pH in the local environment resulting from the nucleotide addition. However, the pH of the local environment can be influenced by the interaction of various materials with hydrogen ions, leading to lower accuracy and less sensitivity to changes caused by nucleotide addition.
As such, an improved sensor array would be desirable.
SUMMARYIn a first aspect, a system includes a sensor including a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. A conductive layer is disposed over the lower surface and at least a portion of the wall surface.
In a second aspect, a system includes an array of sensors, each sensor of the array of sensors including a sensor pad and a well wall structure defining a plurality of wells. Each well is operatively coupled to an associated sensor pad. Each well is further defined by a lower surface disposed over the associated sensor pad. The well wall structure defines an upper surface and defines, for each well, a wall surface extending between the upper surface and the lower surface. In association with a well of the plurality of wells, a conductive layer is disposed over the lower surface and at least a portion of the wall surface.
In a third aspect, a method of forming a sensor system includes forming a well wall structure defining a well operatively coupled to a sensor pad of a sensor. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. The method further includes depositing a conductive layer over the well wall structure. The conductive layer overlies the upper surface, wall surface and lower surface. The method also includes planarizing to remove the conductive layer from the upper surface.
In a fourth aspect, a method of sequencing a polynucleotide includes depositing a polynucleotide conjugated polymeric particle in a well of a system. The system includes a sensor including a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. The system further includes a conductive layer disposed over the lower surface and at least a portion of the wall surface. The method further includes applying a solution including a nucleotide to the well and observing the sensor to detect nucleotide incorporation.
The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
The use of the same reference symbols in different drawings indicates similar or identical items.
DETAILED DESCRIPTIONIn an exemplary embodiment, a system includes a sensor having a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well includes a lower surface disposed over the sensor pad and includes a wall surface defined by the well wall structure. A conductive layer is disposed over the lower surface and at least a portion of the wall surface. The conductive layer can be formed of a metal or a conductive ceramic. Optionally, a passivation layer is disposed over the conductive layer. The passivation layer can include a material having a high intrinsic buffer capacity.
In another exemplary embodiment, a system can be formed by a method including forming a well wall structure over a sensor including a sensor pad. The well wall structure defines a well operatively coupled to the sensor pad. The well has a lower surface disposed over the sensor pad and a wall surface formed by the well wall structure. The well wall structure also defines an upper surface. The method further includes depositing a conductive layer over the well wall structure and planarizing the conductive layer to remove the conductive layer from the upper surface. Optionally, the method can further include depositing a passivation layer over the conductive layer.
In a particular embodiment, a sequencing system includes a flow cell in which a sensory array is disposed, includes communication circuitry in electronic communication with the sensory array, and includes containers and fluid controls in fluidic communication with the flow cell. In an example,
In an embodiment, reactions carried out in the microwell 201 can be analytical reactions to identify or determine characteristics or properties of an analyte of interest. Such reactions can generate directly or indirectly byproducts that affect the amount of charge adjacent to the sensor plate 220. If such byproducts are produced in small amounts or rapidly decay or react with other constituents, multiple copies of the same analyte may be analyzed in the microwell 201 at the same time in order to increase the output signal generated. In an embodiment, multiple copies of an analyte may be attached to a solid phase support 212, either before or after deposition into the microwell 201. The solid phase support 212 may be microparticles, nanoparticles, beads, solid or porous comprising gels, or the like. For simplicity and ease of explanation, solid phase support 212 is also referred herein as a particle. For a nucleic acid analyte, multiple, connected copies may be made by rolling circle amplification (RCA), exponential RCA, or like techniques, to produce an amplicon without the need of a solid support.
In a particular example,
The well wall structure 302 can be formed of one or more layers of material. In an example, the well wall structure 302 can have a thickness (t) extending from the lower surface 308 to the upper surface 310 in a range of 0.3 micrometers to 10 micrometers, such as a range of 0.5 micrometers to 6 micrometers. The wells 304 can have a characteristic diameter, defined as the square root of 4 times the cross-sectional area (A) divided by Pi (e.g., sqrt(4*A/π), of not greater than 5 micrometers, such as not greater than 3.5 micrometers, not greater than 2.0 micrometers, not greater than 1.6 micrometers, not greater than 1.0 micrometers, not greater than 0.8 micrometers or even not greater than 0.6 micrometers.
The system can further include a conductive structure 314 disposed over the sensor pad 306 and at least partially extending along the well wall. For example, the conductive structure 314 can extend at least 40% along the wall surface 312, such as at least 50%, at least 65%, at least 75%, or even at least 85% along the wall surface 312. The upper surface 310 of the well wall structure 302 can be free of the conductive structure 314.
The conductive structure 314 can be formed of a conductive material. For example, the conductive material can have a volume resistivity of not greater than 6.0×107 ohm-m at 25° C. In particular, the volume resistivity can be not greater than 1.0×107 ohm-m at 25° C., such as not greater than 5.0×106 ohm-m, or not greater than 2.0×106 ohm-m at 25° C. The conductive material can be a metallic material or alloy thereof, or can be a ceramic material, or a combination thereof. An exemplary metallic material includes aluminum, copper, nickel, titanium, silver, gold, platinum, or a combination thereof. In particular, the metal can include copper. In another example, the ceramic material can include titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof. In particular, the titanium oxynitride is a high nitrogen content titanium oxynitride. Further, the titanium aluminum nitride can be a low aluminum content titanium aluminum nitride.
Optionally, a passivation structure 316 can be disposed over the conductive structure 314 and optionally the upper surface 310 of the well wall structure 302. In particular, the passivation structure 316 can have a high intrinsic buffer capacity. For example, the passivation structure 316 can have an intrinsic buffer capacity of at least 2×1017 groups/m2. Intrinsic buffer capacity is defined as the surface density of hydroxyl groups on a surface of a material measured at a pH of 7. For example, the passivation structure 316 can have an intrinsic buffer capacity of at least 4×1017 groups/m2, such as at least 8×1017 groups/m2, at least ×1018 groups/m2, or even at least 2×1018 groups/m2. In an example, the passivation structure 316 has an intrinsic buffer capacity of not greater than 1×1021 groups/m2.
In particular, the passivation structure 316 can include an inorganic material, such as a ceramic material. For example, a ceramic material can include an oxide of aluminum, hafnium, tantalum, zirconium, or any combination thereof. In an example, the ceramic material can include an oxide of tantalum. In another example, the ceramic material includes an oxide of zirconium. In a further example, the upper surface 310 can be coated with a pH buffering coating. An exemplary pH buffering coating can include a functional group, such as phosphate, phosphonate, catechol, nitrocatechol, boronate, phenylboronate, imidazole, silanol, another pH-sensing group, or a combination thereof.
In an example, the passivation structure 316 can have a thickness in a range of 5 nm to 100 nm, such as a range of 10 nm to 70 nm, a range of 15 nm to 65 nm, or even a range of 20 nm to 50 nm.
While
The well wall structure 402 defines wells 404 having a lower surface 408 and upper surface 410. A wall surface 412 is defined between the lower surface 408 and the upper surface 410. A conductive structure 414 in contact with the sensor pad 406 can extend across the lower surface 408 of the well 404 and at least partially along a wall surface 412 of the well 404. For example, the conductive structure 414 can extend at least 40% along the wall surface 412, such as at least 50%, at least 65%, at least 75%, or even at least 85% along the wall surface 412. While illustrated as a single layer, the conductive structure 412 can include one or more layers, such as one or more metal layers or one or more ceramic layers.
The conductive structure 414 can be formed of a conductive material. For example, the conductive material can have a volume resistivity of not greater than 6.0×107 ohm-m at 25° C. In particular, the volume resistivity can be not greater than 1.0×107 ohm-m at 25° C., such as not greater than 5.0×106 ohm-m, or not greater than 2.0×106 ohm-m at 25° C. The conductive material can be a metallic material or alloy thereof, or can be a ceramic material, or a combination thereof. An exemplary metallic material includes aluminum, copper, nickel, titanium, silver, gold, platinum, or a combination thereof. In particular, the metal can include copper. In another example, the ceramic material can include titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof. In particular, the titanium oxynitride is a high nitrogen content titanium oxynitride. Further, the titanium aluminum nitride can be a low aluminum content titanium aluminum nitride.
Optionally, one or more passivation layers 416 or 418 can be disposed over the well wall structure 402 and conductive structure 414. In the illustrated example, the passivation layers 416 or 418 are disposed over the well wall structure 402 and conductive structure 414 including an upper surface 410 of the well wall structure 402. In an example, the passivation layer 416 can include aluminum oxide and the passivation layer 418 can include tantalum oxide. Alternatively, one or more additional layers formed of one or more additional materials, such as aluminum oxide, tantalum oxide, or zirconium oxide, can be formed as part of a passivation structure over the conductive structure 414 and the well wall structure 402. In a particular example, the passivation layer 418 defining an outer surface has an intrinsic buffer capacity of at least 2.0×1017 groups/m2. Intrinsic buffer capacity is defined as the surface density of hydroxyl groups on the surface of material measure at a pH of 7. For example, the passivation layer 418 can have an intrinsic buffer capacity of at least 4×1017 groups/m2, such as at least 8×1017 groups/m2, at least 1×1018 groups/m2, or even at least 2×1018 groups/m2. In an example, the passivation layer 418 has an intrinsic buffer capacity of not greater than 1×1021 groups/m2.
In a further example, the passivation layer 418 can be coated with a pH buffering coating. An exemplary pH buffering coating can include a functional group, such as phosphate, phosphonate, catechol, nitrocatechol, boronate, phenylboronate, imidazole, silanol, another pH-sensing group, or a combination thereof.
In a particular example illustrated in
While the wall surface 312 of
While the surfaces 602, 604, or 606 are illustrated by straight lines, some semiconductor or CMOS manufacturing processes can result in structures having nonlinear shapes. In particular, wall surfaces, such as wall surface 608 and upper surfaces, such as upper surface 610, can be arcuate in shape or take various nonlinear forms. While the structures and devices illustrated herewith are depicted as having linear layers, surfaces, or shapes, actual layers, surfaces, or shapes resulting from semiconductor processing may differ to some degree, possibly including nonlinear and arcuate variations of the illustrated embodiment.
Such structures as illustrated in
As illustrated in
As illustrated in
Optionally, one or more passivation layers can be deposited over the conductive layer 920. For example, as illustrated in
Following formation of the conductive layer 920 and optional passivation layer 1022, the contact pad 716 can be exposed. For example, the wells 818 and well wall structure in proximity to the sensor pads 714 can be masked and an access 1124 can be formed to expose the contact pad 716. For example, the contact pad 716 can be exposed using a wet etch, a plasma etch, or combination thereof. In particular, a fluorinated plasma etch process can be utilized to form access 1124 that terminates at the contact pad 716. In a particular example, the access 1124 can be filled with a conductive material to provide an electrical connection to the contact pad 716.
In a first aspect, a system includes a sensor including a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. A conductive layer is disposed over the lower surface and at least a portion of the wall surface.
In an example of the first aspect, the upper surface is free of the conductive layer.
In another example of the first aspect or the above examples, the system further includes a passivation layer disposed over the conductive layer over the lower surface and the wall surface. For example, the passivation layer can be disposed over the upper surface of the well wall structure. In an example, the passivation layer includes an oxide of aluminum, tantalum, hafnium, zirconium, or a combination thereof. In an additional example, the system further includes a coating disposed over the passivation layer. For example, the coating can include a functional group selected from a group consisting of phosphate, phosphonate, catechol, nitrocatechol, boronate, phenylboronate, imidazole, silanol, another pH-sensing group, and a combination thereof.
In a further example of the first aspect or the above examples, the conductive layer is formed of a material having a volume resistivity of not greater than 6.0×107 ohm-m at 25° C. For example, the volume resistivity is not greater than 1.0×107 ohm-m at 25° C., such as not greater than 5.0×106 ohm-m at 25° C. or not greater than 2.0×106 ohm-m at 25° C.
In an additional example of the first aspect or the above examples, the conductive layer includes a metallic material. For example, the metallic material is copper, aluminum, titanium, gold, silver, platinum, or a combination thereof. In another example, the conductive layer includes a ceramic material. For example, the ceramic material is titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof.
In a second aspect, a system includes an array of sensors, each sensor of the array of sensors including a sensor pad and a well wall structure defining a plurality of wells. Each well is operatively coupled to an associated sensor pad. Each well is further defined by a lower surface disposed over the associated sensor pad. The well wall structure defines an upper surface and defines, for each well, a wall surface extending between the upper surface and the lower surface. In association with a well of the plurality of wells, a conductive layer is disposed over the lower surface and at least a portion of the wall surface.
In an example of the second aspect, the upper surface is free of the conductive layer.
In another example of the second aspect or the above examples, the system further include a passivation layer disposed over the conductive layer over the lower surface and the wall surface. In an example, the passivation layer is disposed over the upper surface of the well wall structure. In an additional example, the passivation layer includes an oxide of aluminum, tantalum, hafnium, zirconium, or a combination thereof.
In a further example of the second aspect or the above example, the conductive layer is formed of a material having a volume resistivity of not greater than 6.0×107 ohm-m at 25° C. For example, the volume resistivity is not greater than 1.0×107 ohm-m at 25° C., such as not greater than 5.0×106 ohm-m at 25° C., or not greater than 2.0×106 ohm-m at 25° C.
In an additional example of the second aspect or the above example, the conductive layer includes a metallic material. For example, the metallic material includes copper, aluminum, titanium, gold, silver, platinum, or a combination thereof.
In another example of the second aspect or the above example, the conductive layer includes a ceramic material. For example, the ceramic material is titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof.
In a third aspect, a method of forming a sensor system includes forming a well wall structure defining a well operatively coupled to a sensor pad of a sensor. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. The method further includes depositing a conductive layer over the well wall structure. The conductive layer overlies the upper surface, wall surface and lower surface. The method also includes planarizing to remove the conductive layer from the upper surface.
In an example of the third aspect, the conductive layer is formed of a material having a volume resistivity of not greater than 6.0×107 ohm-m at 25° C. For example, the volume resistivity is not greater than 1.0×107 ohm-m at 25° C., not greater than 5.0×106 ohm-m at 25° C., or not greater than 2.0×106 ohm-m at 25° C.
In another example of the third aspect or the above examples, the conductive layer includes a metallic material. For example, the metallic material is copper, aluminum, titanium, gold, silver, platinum, or a combination thereof.
In an additional example of the third aspect or the above examples, the conductive layer includes a ceramic material. For example, the ceramic material is titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof.
In a further example of the third aspect or the above examples, the method further includes forming a passivation layer over the planarized conductive layer. For example, the passivation layer includes an oxide of aluminum, tantalum, hafnium, zirconium, or a combination thereof.
In another example of the third aspect or the above examples, the method further includes depositing a coating over the passivation layer.
In a fourth aspect, a method of sequencing a polynucleotide includes depositing a polynucleotide conjugated polymeric particle in a well of a system. The system includes a sensor including a sensor pad and a well wall structure defining a well operatively coupled to the sensor pad. The well is further defined by a lower surface disposed over the sensor pad. The well wall structure defines an upper surface and defines a wall surface extending between the upper surface and the lower surface. The system further includes a conductive layer disposed over the lower surface and at least a portion of the wall surface. The method further includes applying a solution including a nucleotide to the well and observing the sensor to detect nucleotide incorporation.
In an example of the fourth aspect, the polymeric particle includes multiple copies of the polynucleotide, and a change in ionic concentration results from incorporation of the nucleotide with the polynucleotide. The change in ionic concentration changes an electrical characteristic of the sensor indicative of the nucleotide incorporation.
As used herein, the terms “over” or “overlie” refers to a position away from a surface relative to a normal direction from the surface. The terms “over” or “overlie” are intended to permit intervening layers or direct contact with an underlying layer. As described above, layers that are disposed over or overlie another layer can be in direct contact with the identified layer or can include intervening layers.
Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.
In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification and FIG.s are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of features is not necessarily limited only to those features but may include other features not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive-or and not to an exclusive-or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
Also, the use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.
After reading the specification, skilled artisans will appreciate that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, references to values stated in ranges include each and every value within that range. cm What is claimed is:
Claims
1. A system comprising:
- a sensor including a sensor pad;
- a well wall structure defining a well operatively coupled to the sensor pad, the well further defined by a lower surface disposed over the sensor pad, the well wall structure defining an upper surface and defining a wall surface extending between the upper surface and the lower surface;
- a conductive layer disposed over the lower surface and extending incompletely up the wall surface; and
- a layer disposed over the conductive layer over the lower surface and the wall surface, the layer including an oxide of aluminum, tantalum, hafnium, zirconium, or a combination thereof.
2. The system of claim 1, wherein the upper surface is free of the conductive layer.
3. The system of claim 1, wherein the layer is further disposed over the upper surface of the well wall structure.
4. The system of claim 1, further comprising a coating disposed over the layer.
5. The system of claim 4, wherein the coating includes a functional group selected from a group consisting of phosphate, phosphonate, catechol, nitrocatechol, boronate, phenylboronate, imidazole, silanol, another pH-sensing group, and a combination thereof.
6. The system of claim 1, wherein the conductive layer is formed of a material having a volume resistivity of not greater than 6.0×10̂7 ohm-m at 25° C.
7. The system of claim 6, wherein the volume resistivity is not greater than 1.0×10̂7 ohm-m at 25° C.
8. The system of claim 7, wherein the volume resistivity is not greater than 5.0×10̂6 ohm-m at 25° C.
9. The system of claim 8, wherein the volume resistivity is not greater than 2.0×10̂6 ohm-m at 25° C.
10. The system of claim 1, wherein the conductive layer includes a metallic material.
11. The system of claim 10, wherein the metallic material is copper, aluminum, titanium, gold, silver, platinum, or a combination thereof.
12. The system of claim 1, wherein the conductive layer includes a ceramic layer.
13. The system of claim 12, wherein the ceramic material is titanium nitride, titanium aluminum nitride, titanium oxynitride, or a combination thereof.
14. A method of forming a sensor system, the method comprising:
- forming a well wall structure defining a well operatively coupled to a sensor pad of a sensor, the well further defined by a lower surface disposed over the sensor pad, the well wall structure defining an upper surface and defining a wall surface extending between the upper surface and the lower surface;
- forming a conductive layer over the lower surface and extending incompletely up the wall surface; and
- forming a layer disposed over the conductive layer over the lower surface and the wall surface, the layer including an oxide of aluminum, tantalum, hafnium, zirconium, or a combination thereof.
15. The system of claim 14, wherein the conductive layer is formed of a material having a volume resistivity of not greater than 6.0×10̂7 ohm-m at 25° C.
16. The system of claim 15, wherein the volume resistivity is not greater than 1.0×107 ohm-m at 25° C.
17. The system of claim 16, wherein the volume resistivity is not greater than 5.0×106 ohm-m at 25° C.
18. The system of claim 17, wherein the volume resistivity is not greater than 2.0×106 ohm-m at 25° C.
19. The system of claim 14, wherein the conductive layer includes a metallic material.
20. The system of claim 19, wherein the metallic material is copper, aluminum, titanium, gold, silver, platinum, or a combination thereof.
Type: Application
Filed: Feb 8, 2017
Publication Date: Jun 1, 2017
Inventors: Shifeng LI (Fremont, CA), James BUSTILLO (Castro Valley, CA), Wolfgang HINZ (Killingworth, CT)
Application Number: 15/428,126