Sensing die and method of manufacturing the same

Abstract

A sensing die (100) includes a substrate (102) including a non-conductive surface (106) and a bond pad (144) sealed by a sealing material (170). A wire (120) is disposed on the non-conductive surface (106) and an ion barrier passivation layer (130) is disposed over the wire (120). A sensor electrode (146) is disposed adjacent the passivation layer (130) and a portion of the passivation layer (130) is missing, providing a portion of the wire (120) for electrical coupling. The sensor electrode (146) extends from over the passivation layer (130) to the exposed portion of the wire (120) and is coupled to the portion of the wire (120) provided for electrical coupling. The sensor electrode (146) over the passivation layer (130) is exposed for direct contact with an analyte. The wire (120) is formed of a material that maintains the morphology of the wire (120) after deposition of the passivation layer (130).

Description

[0001] This invention relates to a sensing die, which includes, for example, a substrate for placement within a device package, the substrate carrying electrodes. The invention also relates to a method of manufacturing a sensing die, which includes, for example, providing a substrate carrying electrodes for placement within a device package.

[0002] Electrochemical impedance spectroscopy (EIS) is a powerful tool for studying fundamental electrochemical reactions occurring within a container filled with a medium (i.e., the analyte). EIS measurements are obtained by varying the voltage (voltammetry) and current (amperometrics) of the test "cell" at different frequencies to measure how the cell's impedance changes with frequency. Examples of such analyses include blood analysis described in U.S. Patent No. 11,187,701 B2, and water analysis in a washing machine described in European Patent Publication No. EP 3268529 A1.

[0003] In applications involving rechargeable battery cells (such as lithium-ion (Li-ion) battery cells), it is difficult to accurately determine the state of charge (SOC) or state of health of a battery cell because it is challenging to verify the amount of charge retained by each cell after a charging cycle. Furthermore, measurements of open-circuit potential difference do not provide detailed information about the load on the electrodes. In these situations, Electrochemical Indication (EIS) technology can be used to obtain crucial information about the battery's SOC and state of health, or to detect and analyze faults in the battery pack.

[0004] For battery applications, although EIS is widely used in laboratory settings, it is a relatively specialized technology that typically requires expensive and bulky equipment to achieve accurate results. Therefore, there is growing interest in using EIS for "in-situ" state monitoring of batteries for a variety of applications.

[0005] While it is known to implement EIS sensors on Micro-Electro-Mechanical Systems (MEMS) chips, such as those described in U.S. Patent No. 11,150,208, and it is also known to use electrodes relative to vehicle batteries for performance measurements, as described in U.S. Patent Publication No. US 2019 / 210472 A1, the sensitive components of the EIS sensor are prone to degradation when in contact with the analyte medium. U.S. Patent Publication No. 2021 / 020528 A1 discloses a package comprising a printed circuit board with a cavity in which the sensor is disposed. The sensitive components of the sensor are protected from the medium by a cover package and an O-ring seal. However, this configuration results in a larger-than-expected sensor package.

[0006] Furthermore, a third type of so-called reference electrode is known to be used when monitoring battery performance, especially Li-ion battery cells. Reference electrodes used for monitoring Li-ion battery cells are typically made of lithium metal. However, lithium metal is difficult to process and is highly reactive with the electrolyte used in Li-ion battery cells. In addition, introducing metal strips or brittle oxide layers into the electrolyte reduces the gravimetric and volumetric energy densities of the battery cell. Additional connections are also required for each cell of the battery, which must be attached to a separate readout / analysis tool, making large-scale integration extremely challenging and / or significantly increasing the production cost of the battery cell.

[0007] In addition, for some applications, besides EIS analysis, it is desirable to measure the pressure and / or temperature of the analyte or to perform chemical measurements simultaneously with EIS measurements.

[0008] According to a first aspect of the invention, a sensing die is provided, comprising: a substrate including a non-conductive surface and bonding pads, the bonding pads being sealed by a sealing material; a wire disposed on the non-conductive surface; an ion-barrier passivation layer disposed above the wire; and a sensor electrode disposed adjacent to the ion-barrier passivation layer; wherein a portion of the ion-barrier passivation layer is missing, thereby providing a portion of the wire for electrical coupling; the sensor electrode extends from above the ion-barrier passivation layer to the portion of the wire provided for electrical coupling and is coupled to an exposed portion of the wire provided for electrical coupling; the sensor electrode above the ion-barrier passivation layer is exposed to directly contact an analyte; and the wire is formed of a material that maintains the morphology of the wire after deposition of the ion-barrier passivation layer.

[0009] A sensor device may include a device package (e.g., a lead frame package) and a sensing die.

[0010] An ion-blocking passivation layer can be configured to block ions of the analyte during use.

[0011] The wire can be formed of metal. The wire can be formed of silicon alloy. For example, the wire can be a silicon alloy containing metals such as nickel, platinum, titanium, cobalt, aluminum, and copper, which diffuse into the surface of the substrate.

[0012] The ion-blocking passivation layer can be a stoichiometric passivation layer.

[0013] The stoichiometric passivation layer can be a stoichiometric nitride passivation layer. The stoichiometric passivation layer can be a silicon carbide layer. The ion-barrier passivation layer can be a diamond-like carbon (DLC) layer.

[0014] The ion barrier passivation layer can be a stack of ion barrier passivation layers, which includes an intermediate oxide material layer located below and adjacent to the ion barrier passivation layer.

[0015] The wires can be buried beneath the intermediate oxide material layer.

[0016] A portion of the diffusion-blocking material can be placed between the sensor electrode and the exposed portion of the metal wire.

[0017] The sensor electrodes can be made of metal. The metal can be a precious metal.

[0018] The sensor electrodes can be formed from transition metal oxides or transition metal phosphates.

[0019] The die may further include: another wire disposed on a non-conductive surface and located below the ion-barrier passivation layer; and another sensor electrode disposed adjacent to the ion-barrier passivation layer; wherein another portion of the ion-barrier passivation layer may be missing, thereby providing a portion of the other wire for electrical coupling; the other sensor electrode may extend from above the ion-barrier passivation layer to the portion of the other wire provided for electrical coupling, and may be coupled to the portion of the other wire provided for electrical coupling; the other sensor electrode above the ion-barrier passivation layer may be exposed to direct contact with the analyte; and the other wire may be formed of a material that maintains the morphology of the other wire after the deposition of the ion-barrier passivation layer.

[0020] The substrate may be a silicon substrate, which includes an insulating oxide layer disposed on the silicon substrate to provide a non-conductive surface of the substrate.

[0021] The substrate may include a temperature sensor disposed on the substrate.

[0022] According to a second aspect of the invention, a sensor device is provided, comprising: a sensing die as described above with respect to a first aspect of the invention; and a device package; wherein the device package is a molded device package providing sidewalls; the substrate is elongated having a proximal end and a distal end; and the sidewalls are arranged to securely hold the proximal end of the substrate within the sidewalls.

[0023] Molded device packages can be configured to define cavities having an internal volume defined by openings, sidewalls, and a base.

[0024] The substrate may include: a recess formed within the substrate, defining an open sensor element cavity; a film layer disposed adjacent to the substrate; the substrate and the film layer may cooperate to close the open sensor element cavity and define a closed cavity; and a strain gauge element or displacement gauge element disposed on the film.

[0025] The substrate can be held in place by the sidewalls, allowing the substrate to be cantilevered from the sidewalls; and the sidewalls and base of the molded device package can be integrally formed.

[0026] The opening of the cavity can be fluidly connected to the internal volume of the cavity, and the substrate can be cantilevered from the sidewall of the cavity.

[0027] The device may further include: an interface die including another bonding pad; and a bonding wire connected at its first end to the other bonding pad; wherein a sensor electrode may be electrically coupled to the bonding pad via a wire; a second end of the bonding wire may be connected to the bonding pad; a substrate and an interface die may be disposed on a lead frame within a device package; and the bonding pad, the other bonding pad, the interface die, and the bonding wire may be sealed in a sealing material.

[0028] According to a second aspect of the present invention, a method for manufacturing a sensor die is provided, the method comprising: providing a substrate including a non-conductive surface and bonding pads; sealing the bonding pads in a sealing material; providing a wire on the non-conductive surface; disposing an ion-barrier passivation layer over the wire; and disposing a sensor electrode on the ion-barrier passivation layer; wherein a portion of the ion-barrier passivation layer is removed to expose a portion of the wire for electrical coupling; the sensor electrode is disposed on the ion-barrier passivation layer to extend from above the ion-barrier passivation layer to the exposed portion of the wire, and the sensor electrode is coupled to the exposed portion of the wire; and the wire is formed from a material that maintains the shape of the wire after deposition of the ion-barrier passivation layer.

[0029] Therefore, a sensor device and a method for manufacturing the same can be provided. The sensor device can utilize electrodes that are not easily degraded by direct contact with the analyte, supporting the performance of electrochemical impedance spectroscopy. For example, in the case of a battery cell, it is possible to determine the cell's state of charge and / or state of health. Furthermore, the sensor device can measure the cell's power state and the rate at which a given cell can be charged and / or discharged.

[0030] Referring to the accompanying drawings, which are merely examples, at least one embodiment of the invention will now be described, in which:

[0031] Figure 1 This is a schematic diagram of a sensing element constituting an embodiment of the present invention;

[0032] Figure 2 This constitutes another embodiment of the present invention, which is disposed within the device package. Figure 1 A schematic diagram of a variant of the sensing element;

[0033] Figure 3 It is manufacturing Figure 1 A flowchart of a simplified variant of the sensing element method; and

[0034] Figures 4 to 14 yes Figure 3 A schematic diagram of different formation stages of a simplified variant of the sensing element described in the method.

[0035] Throughout the following description, the same reference numerals will be used to identify the same parts.

[0036] See Figure 1 The sensing die 100 includes a substrate 102 having an n-type or p-type doped diffusion region 104 formed therein, depending on the intended application of the sensing die 100. In this example, the substrate or bulk 102 is n-type doped, therefore, the diffusion region 104 is a p-type doped diffusion region. A first oxide layer 106 is deposited on the substrate 102 including the p-type doped diffusion region 104 to isolate subsequent deposits from the substrate 102 unless specifically contacted with the substrate 102. Thus, the first oxide layer 106 provides a non-conductive surface for the substrate 102. In this regard, a first via 108 and a second via 110 are formed in the first oxide layer 106, and a first diffusion barrier layer 112 and a second diffusion barrier layer 114 are located within the first via 108 and the second via 110, respectively, contacting the p-type diffusion region 104. A first conductive line 116 is disposed on the first oxide layer 106 and extends into the first hole 108 to fill the first hole 108 and contact the first diffusion barrier layer 112. A second conductive line 118 is also disposed on the first oxide layer 106 and extends into the second hole 110 to fill the second hole 110 and contact the second diffusion barrier layer 114.

[0037] Furthermore, the third electrode wire 120 and the fourth electrode wire 122 are formed on the first oxide layer 106. Although Figure 1 Not shown, but in this example, the third electrode lead 120 and the fourth electrode lead 122 are operatively coupled to corresponding electrical signal terminals or ports, such as signal outputs. Alternatively, additional sensing elements may be formed as part of the sensing die 100, such as a deposition of a high-temperature resistant material in an interdigitated configuration 123 (see below for the temperature used in forming the passivation layer). The additional sensing elements may be made of a high-melting-point metal (e.g., tungsten) capable of withstanding the high temperatures (e.g., about 800°C) used in certain semiconductor manufacturing techniques such as low-pressure chemical vapor deposition (LPCVD). The additional sensing elements may be formed on the first oxide layer 106 to form part of the capacitive sensing element 124. Similarly, a temperature sensing element 126 and / or a pressure sensing element (not shown) may be formed as part of the sensing die 100 by any suitable manufacturing process integrated into the process used to form the sensing die 100, particularly the process used to form a chemical sensing element.

[0038] A second oxide layer 128 constituting the intermediate oxide layer is disposed above a deposit on the first oxide layer 106, such as the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122, as well as any other construction 123 associated with other sensing elements. Thus, the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122, and any construction, are effectively buried beneath the second oxide layer 128. The second oxide layer 128 is optional and, in this example, is part of a passivation stack comprising a stoichiometric material layer 130 (such as a stoichiometric nitride layer) disposed adjacent to the second oxide layer 128. In this example, the second oxide layer 128 is disposed to protect the electrode conductors 116, 118, 120, and 122 from oxidation. However, in other embodiments, modifications to the operation of the furnace in which the sensing die 100 is manufactured may eliminate the need for the second oxide layer 128.

[0039] In other examples, the passivation stack may comprise one or more layers of material configured to block ions of analytes intended to be used with the sensing die 100 during use. In this regard, as those skilled in the art will understand, the passivation layer is an ion-blocking passivation layer. The passivation stack may comprise any suitable material, for example, capable of blocking lithium ions, hydroxide ions, sodium ions, and / or hydrogen ions. For example, in other examples, the stoichiometric material layer 130 may be formed of silicon carbide or diamond-like carbon (DLC). Where the passivation stack is a single passivation layer, those skilled in the art will understand that reference to passivation stack herein refers to a single passivation layer.

[0040] The passivation stack includes a third aperture 132, a fourth aperture 134, and a fifth aperture 136 formed therein to provide access to the first conductor 116 and the third conductor 120 and the fourth conductor 122. A third diffusion barrier layer 138 is located within the third aperture 132 and over the portion of the first conductor 116 accessible via the third aperture 132; a fourth diffusion barrier layer 140 is located within the fourth aperture 134 and over the portion of the third conductor 120 accessible via the fourth aperture 134; and a fifth diffusion barrier layer 142 is located within the fifth aperture 136 and over the portion of the fourth conductor 122 accessible via the fifth aperture 136.

[0041] Bonding pads 144 are disposed on the stoichiometric material layer 130 and extend into the third via 132, contacting the third diffusion barrier layer 138. However, in other examples, the material of the passivation layer 130 may not be present beneath the bonding pads 144, and another material may be disposed in its place. For example, the passivation layer 130 may be deposited using a technique different from LPCVD, such that the area where the bonding pads 144 are to be disposed does not contain the material of the passivation layer 130. Alternatively, the passivation layer 130 may be deposited as described above, and areas of material without the passivation layer 130 may be etched using any suitable etching technique. Subsequently, the material on which the bonding pads 144 will be formed is deposited in the areas of material without the passivation layer 130. This method of forming bonding pads 144 on a material different from the passivation layer 130 is permissible, provided that at least when the sensor die 100 is packaged, the bonding pads 144 are ultimately covered by a sealing material, as described below.

[0042] A first analyte electrode 146 constituting the sensor electrode is also disposed on the stoichiometric material layer 130 and extends into the fourth aperture 134, contacting the fourth diffusion barrier layer 140. A second analyte electrode 148 constituting the other sensor electrode is also disposed on the stoichiometric material layer 130 and extends into the fifth aperture 136, contacting the fifth diffusion barrier layer 142. Bonding pads 144 may be electrically coupled to the first analyte electrode 146 or the second analyte electrode 148, depending on application requirements, for example via a first wire 116 or a second wire 118 and / or a third wire 120 and / or a fourth wire 122. The first analyte electrode 146 and the second analyte electrode 148 are exposed during use to directly contact the analyte, unlike the bonding pads, which are encapsulated by a sealing material (e.g., potting material). In this example, at least one of the first analyte electrode 146 and the second analyte electrode 148 is formed of any suitable compound that supports the stable maintenance of a constant electrochemical potential, such as a material capable of intercalating lithium ions, like a transition metal oxide or a metal phosphate. However, in other examples, the first analyte electrode 146 and the second analyte electrode 148 may be formed of two different transition metals, or they may be formed of a combination of a transition metal for one electrode and a transition metal phosphate for the other electrode. For the examples above, lithium iron phosphate (LiFePO4), titanium dioxide (TiO2), or vanadium oxide (V) x O yThe first analyte electrode 146 and the second analyte electrode 148 are formed from suitable materials. In other examples, at least one of the first analyte electrode 146 and the second analyte electrode 148 may also be formed from a chemically inert material, or both the first analyte electrode 146 and the second analyte electrode 148 may be formed from chemically inert materials. In the above examples, the first analyte electrode 146 and the second analyte electrode 148 are formed using sputtering technology. However, in other examples, microchannel particle deposition (MPD) or screen printing technology may be used to deposit, for example, lithium titanate (Li4Ti5O). 12 Lithium iron phosphate (LiFePO4) or lithium iron phosphate (LiFePO4) may be used as the first analyte electrode 146 and / or the second analyte electrode 148. It should be understood that these compounds are typically mixed with conductive agents (such as metal particles or carbon black) to form a conductive "ink".

[0043] The sensing die 100 is typically disposed within a device package and connected to an integrated circuit die (e.g., an interface die) via bonding pads 144 (and optionally other bonding pads) and wirebonding. The bonding pads 144 are covered by the sealing material mentioned above. When the bonding pads 144 are not formed on the passivation layer 130 mentioned above, the bonding pads 144 are also covered by the sealing material. In such examples, the interface die may also be sealed within the sealing material.

[0044] Turning Figure 2 In another example, the sensing die 100 is housed within a device package, and it should be understood that any suitable package can be used, such as a frame package or a leadframe-based package. In this example, the device package is a leadframe package 147, which has been formed by a molding process and is generally elongated, including a plurality of pins / leads extending through the sides of the package mold to connect at one end to one or more dies within the package and at the other end to a circuit board. Other packages can be used, such as ceramic packages, laminated packages, or virtually any package or structure capable of supporting at least two cavities therein. Although the integration of a capacitive sensor and a temperature sensor into the sensing die 100 has been described above, those skilled in the art will understand that other sensing elements, such as a pressure sensor, can also be integrated into the sensing die 100. In this example, the sensing die 100 also includes a pressure sensing element.

[0045] The leadframe package 147 includes a first die receiving subframe 148 and a second die receiving subframe 150. In this example, the volume of the first die receiving subframe 148 is generally superrectangular in form. Similarly, in this example, the volume of the second die receiving subframe 150 is generally superrectangular in form.

[0046] In this example, the first die receiving subframe 148 includes a first base 152 and a peripheral sidewall 153, and the second die receiving subframe 150 includes a second base 154. Therefore, the first die receiving subframe 148 provides a first cavity 156. The first base 152 is integrally formed with the peripheral sidewall 153 and defines an opening 155 in fluid communication with the internal volume of the first cavity 156, and the second die receiving subframe 150 provides a second cavity 158. The first die receiving subframe 148 and the second die receiving subframe 150 are separated by a shared partition wall (not shown) that forms part of the peripheral sidewall 153 of the first cavity 156. In this example, the partition wall includes a generally centrally located cutout (also not shown) through which the sensing die 100 extends. The sensing die 100 bridges the internal volumes of the first die receiving subframe 148 and the second die receiving subframe 150, thereby bridging the first cavity 156 and the second cavity 158. The sensing die 100 resides substantially within the first cavity 156, meaning that the majority of the sensing die 100 resides within the first cavity 156, but extends across the partition wall, through the cutout, and into the second cavity 158. In this regard, the first proximal end 160 of the sensing die 100 closest to the bonding pad 144 extends sufficiently into the second cavity 158, such that the bonding pad 144 of the sensing die 100 resides within the second cavity 158. In this example, the first proximal end 160 of the sensing die 100 extends sufficiently into the second cavity 158, so that at least a portion of the bonding pad 144 is accessible for connection within the second cavity 158. It should be understood that the bonding pad 144 is described in the singular for clarity and brevity, but in other examples, the sensing die 100 may include multiple bonding pads.

[0047] In this example, the first cavity 156 is deeper than the second cavity 158. Therefore, the first cavity 156 is stepped relative to the second cavity 158. In this example, the leadframe package 147 is pre-molded and is generally elongated in shape, such as being rectangular in shape, and includes a first side and a second side (not shown) that respectively carry a first plurality of pins and a second plurality of pins (not shown) of the leadframe package 147.

[0048] In addition to the sensing die 100, an integrated circuit die (e.g., an interface die 164) is also disposed in the second die receiving subframe 150. In this example, the interface die 164 is a driver or signal conditioning integrated circuit. The interface die 164 includes one or more bonding pads 166. In this example, some of the bonding pads (not shown) of the interface die 164 are connected to pins of the leadframe package 147 via first bonding leads (not shown). Another bonding pad 166 of the interface die 164 is coupled to the bonding pad 144 of the sensing die 100 via another bonding lead 168. Those skilled in the art will understand that the connection configuration described above is for illustrative purposes only, and other connection configurations are entirely conceivable depending on the design of the sensing die 100 and / or the interface die 164, and the configuration of the leadframe package 147. However, it should be understood that at least some connections are formed between the interface die 164 and the sensing die 100 within the second cavity 158.

[0049] The pressure sensing element of the sensing die 100 includes a recess formed in the substrate 100 to define an open pressure sensor element cavity 162. Figure 2 A membrane 163 is disposed above the substrate 102 to enclose the open pressure sensor element cavity 162. A strain gauge element or displacement gauge element (not shown) is disposed on the membrane 163 to provide pressure sensing capability when the membrane 163 deforms in response to pressure changes within the first cavity 156.

[0050] The components of the second cavity 158, such as the interface die 164, the carrier bonding pads 144 of the sensing die 100, and the first end 160 of the bonding lead 168, are encapsulated or wrapped in a sealing material 170, thus preventing exposure to any analytes. This sealing material 170 is, for example, an epoxy material that can withstand harsh media. The sealing material 170 is applied to the target area to be sealed, unlike transfer molding, and fills the second cavity 158. In this example, the sealing material 170 is also a high-viscosity material. More specifically, in this example, a droplet is applied to fill the second subframe volume or cavity 158.

[0051] Therefore, most of the sensing die 100 is suspended within the first cavity 156, for example, cantilevered from the partition wall. In other examples, the lead frame package 147 may take different shapes and does not require providing a first base 152 below the exposed portion of the sensing die 100 and a peripheral sidewall 153 surrounding the exposed portion of the sensing die 100.

[0052] Now refer to Figures 3 to 14The manufacture of the sensing die 100 is described, but in a modified form that does not have a capacitive sensing element 124, a temperature sensing element 126, or a pressure sensing element and only has a first chemical sensor and a second chemical sensor.

[0053] First, substrate 102 is formed and provided using any suitable substrate fabrication technology (step 200). Figure 4 Subsequently, p+ diffusion regions 104 are optionally formed in substrate 102 using any suitable photolithography technique (step 202). Figure 5 Then, a first oxide layer 106 is formed on the substrate 102 including the p+ diffusion region 104 (step 204). Figure 6 Subsequently, the first hole 108 and the second hole 110 are etched into the first oxide layer 106 using any suitable photolithography technique (step 206). Figure 7 ), to expose a selected area of ​​the p+ diffusion region 104, and then deposit the first diffusion barrier layer 112 and the second diffusion barrier layer 114 into the first aperture 108 and the second aperture 110 (step 208) ( Figure 8 Then, the first conductive line 116, the second conductive line 118, the third conductive line 120, and the fourth conductive line 122 are patterned using any suitable photolithography technique and deposited onto the first oxide layer 106 and into the first hole 108 and the second hole 110 (step 210), such that the first diffusion barrier layer 112 and the second diffusion barrier layer 114 are in contact with the first conductive line 116 and the second conductive line 118. Figure 9 In this regard, the materials from which the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122 are formed are chosen to ensure that the respective morphology or shape of each of the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122 is maintained after the deposition of the stoichiometric material layer or the ion-barrier material layer 130. This is because if certain materials are chosen for forming the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122, the temperatures used by certain processes (e.g., liquid phase chemical vapor deposition, LPCVD) for depositing the stoichiometric material layer 130 may melt these materials. However, in the case of LPCVD, tungsten is a suitable material for forming the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122.

[0054] After forming the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122, in this example, a passivation stack is formed by first depositing a second oxide layer 128 on the first conductor 116, the second conductor 118, the third conductor 120, and the fourth conductor 122, as well as the remaining exposed portion of the first oxide layer 106 (step 212). Figure 10 Subsequently, a stoichiometric material layer 130 is deposited on the second oxide layer 128 (step 214). Figure 11 Then, using any suitable photolithography technique, the third hole 132, the fourth hole 134, and the fifth hole 136 are patterned and etched into the passivation stack (step 216). Figure 12 This exposes selected areas of the first conductor 116, the third conductor 120, and the fourth conductor 122. Subsequently, the third diffusion barrier layer 138, the fourth diffusion barrier layer 140, and the fifth diffusion barrier layer 142 are deposited into the third aperture 132, the fourth aperture 134, and the fifth aperture 136 (step 218). Figure 13 Subsequently, bonding pads 144 and first analyte electrodes 146 and 148 are deposited using any suitable photolithography technique (steps 220 and 222), such that the material of bonding pads 144 extends into the third hole 132 and contacts the third diffusion barrier layer 138, and the first and second analyte electrodes 146 and 148 extend from the material thereon into the fourth and fifth holes 134 and 136, respectively, and contact the fourth and fifth diffusion barrier layers 140 and 142, respectively. Figure 14 In fact, as mentioned above, the first analyte electrode 146 and the second analyte electrode 148 can be formed using MPD or screen printing technology and "ink," which includes, for example, lithium titanate (Li4Ti5O). 12 (or lithium iron phosphate (LiFePO4) and conductive agents.)

[0055] Since the sensing die 100 no longer withstands the high temperatures of LPCVD technology, other structures can be deposited if needed after the passivation stack is formed, such as for providing other sensing elements or heating elements.

[0056] Those skilled in the art will understand that the above implementations are merely examples of various implementations conceivable within the scope of the appended claims. Indeed, it should be understood that, for example, the wires described in the examples set forth herein may be formed of metals (e.g., tungsten mentioned above). However, in other examples, one or more wires may be formed of silicon alloys; for example, one or more wires may be an alloy of silicon and metals, such as alloys comprising nickel, titanium, cobalt, or titanium and tungsten. Specific examples of suitable metal silicides in this regard include: titanium tungsten silicide (TiWSi), titanium silicide (TiSi), titanium nitride (TiN), tantalum silicide (TaSi), cobalt silicide (CoSi), and nickel silicide (NiSi). Such compounds are particularly suitable when using LPCVD technology to deposit a stoichiometric passivation layer 130, because tungsten and the aforementioned silicon alloys melt at higher temperatures, thus allowing wires formed from any of these materials to retain their respective morphology / shape, thereby resisting the deposition of the stoichiometric passivation layer 130. In one example, a metal may be diffused into the silicon substrate 102 to form the silicide mentioned above. With the continuous improvement of other deposition technologies, alternatives to LPCVD, such as atomic layer deposition (ALD), can be adopted. This technology operates at lower temperatures than LPCVD, thus offering greater flexibility in selecting materials for forming one or more conductors without sacrificing the conductor's morphology / shape. For example, one or more conductors can be formed from copper, aluminum, or tungsten. However, when using ALD, silicon nitride is not a suitable material for forming the stoichiometric passivation layer 130; therefore, other suitable materials should be selected, such as alumina (Al₂O₃), zirconium oxide (ZrO₂), hafnium oxide (HfO₂), or tantalum oxide (Ta₂O₃). Furthermore, when selecting materials for forming one or more conductors, it is desirable to choose materials with coefficients of thermal expansion as close as possible to those used to form the passivation layer, in order to minimize the generation of mechanical stress in the sensing die 100 during its formation.

[0057] In the above example, the sensing die 100 includes a first analyte electrode 146 and a second analyte electrode 148. However, those skilled in the art will understand that, depending on the intended application of the sensing die 100, more or fewer electrodes may be formed for sensing. For example, the sensing die 100 may be formed to have a single analyte electrode or to have more than two analyte electrodes.

Claims

1. A sensing die, comprising: A substrate, the substrate comprising a non-conductive surface and bonding pads, the bonding pads being sealed with a sealing material; A wire, wherein the wire is disposed on the non-conductive surface; An ion-blocking passivation layer is disposed above the conductor; as well as Sensor electrodes, wherein the sensor electrodes are configured adjacent to the ion-blocking passivation layer; in A portion of the ion-blocking passivation layer is missing, thereby providing a portion of the wire for electrical coupling; The sensor electrode extends from above the ion-blocking passivation layer to a portion of the wire provided for electrical coupling, and is coupled to an exposed portion of the wire provided for electrical coupling; The sensor electrode above the ion-blocking passivation layer is exposed to direct contact with the analyte; and The conductor is formed of a material that maintains the shape of the conductor after the deposition of the ion-barrier passivation layer.

2. The die as described in claim 1, wherein, The ion-blocking passivation layer is a stoichiometric passivation layer.

3. The die as described in claim 1 or claim 2, wherein, The ion-blocking passivation layer is a stack of ion-blocking passivation layers, and the stack of ion-blocking passivation layers includes an intermediate oxide material layer located below and adjacent to the ion-blocking passivation layer.

4. The die as claimed in any of the preceding claims, wherein, A portion of the diffusion-blocking material is disposed between the sensor electrode and the exposed portion of the metal wire.

5. The die as claimed in any of the preceding claims, wherein, The sensor electrodes are made of metal.

6. The die as described in claim 5, wherein, The metal in question is a precious metal.

7. The die as described in any one of claims 1 to 4, wherein, The sensor electrodes are formed from transition metal oxides or transition metal phosphates.

8. The die as described in any of the preceding claims, further comprising: Another wire is disposed on the non-conductive surface and located below the ion-blocking passivation layer; Another sensor electrode is positioned adjacent to the ion-blocking passivation layer; in Another portion of the ion-blocking passivation layer is missing, thereby providing a portion of the other wire for electrical coupling; The other sensor electrode extends from above the ion-blocking passivation layer to a portion of the other wire provided for electrical coupling, and is coupled to the portion of the other wire provided for electrical coupling; The other sensor electrode above the ion-blocking passivation layer is exposed to direct contact with the analyte; and The other conductor is formed of a material that maintains the shape of the other conductor after the deposition of the ion-barrier passivation layer.

9. The die as claimed in any of the preceding claims, wherein, The substrate is a silicon substrate, and the silicon substrate includes an insulating oxide layer disposed on the silicon substrate to provide the non-conductive surface of the substrate.

10. The die as claimed in any of the preceding claims, wherein, The substrate includes a temperature sensor disposed on the substrate.

11. A sensor device, comprising: The sensing die as described in any of the preceding claims; as well as Device packaging; among which, The device package is a molded device package with sidewalls provided; The substrate is elongated with a proximal end and a distal end; and The sidewall is arranged to hold the proximal end of the substrate within the sidewall.

12. The device of claim 11, wherein, The substrate includes: A recessed portion formed within the substrate defines an open sensor element cavity. A film layer, configured adjacent to the substrate, wherein the substrate cooperates with the film layer to enclose the cavity portion of the open sensor element and define the enclosed cavity; and Strain gauge elements or displacement gauge elements are disposed on the membrane.

13. The device as claimed in claim 11 or claim 12, wherein, The substrate is held in place by the sidewall, such that the substrate is cantilevered from the sidewall; and The sidewall and the base of the molded device are integrally formed.

14. The device as claimed in any one of claims 11 to 13, further comprising: Interface die, including another bonding pad; and A bonding wire, at a first end of which is connected to the other bonding pad; in The sensor electrode is electrically coupled to the bonding pad via the wire; The second end of the bonding lead is connected to the bonding pad; The substrate and the interface die are disposed on a lead frame within the device package; and The bonding pad, the other bonding pad, the interface die, and the bonding wire are sealed in the sealing material.

15. A method for manufacturing a sensor die, the method comprising: Provides a substrate including a non-conductive surface and bonding pads; The bonding pads are sealed in a sealing material; A wire is provided on the non-conductive surface; An ion-blocking passivation layer is disposed above the wire; as well as Sensor electrodes are disposed on the ion-blocking passivation layer; in A portion of the ion-blocking passivation layer is removed to expose a portion of the wire for electrical coupling; A sensor electrode is disposed on the ion-blocking passivation layer to extend from above the ion-blocking passivation layer to the exposed portion of the wire, and the sensor electrode is coupled to the exposed portion of the wire; and The conductor is formed from a material that maintains the shape of the conductor after the deposition of the ion-barrier passivation layer.

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