HARTWELL, Peter George (1501 Page Mill Rd, Palo Alto, California, 94304-1100, US)
| CLAIMS What is claimed is: 1. A method 500 for producing a multi-sensor integrated chip on a substrate, comprising: implanting 510 a dopant selectively on the substrate 100 using an implant mask to form at least one implanted doped feature for a first sensor or a second sensor, wherein the first sensor measures a first environmental state and the second sensor measures a second environmental state different from the first environmental state; depositing 520 a first conductive layer 1 12 selectively on the substrate 100 to form at least one first conductive feature for the first sensor or the second sensor; depositing 530 a water absorbing dielectric layer 114 on the substrate 100 to form at least one insulator feature for the first sensor or the second sensor; and depositing 540 a second conductive layer 1 16 selectively on the substrate 100 to form at least one second conductive feature for the first sensor or the second sensor, wherein each of the first sensor and second sensor includes at least one implanted doped feature, first conductive feature, insulator feature, or second conductive feature. The method of claim 1, further comprising isotropic release etching the substrate, the first conductive layer, the water absorbing dielectric layer, or the second conductive layer selectively using a first mechanical mask to form at least one mechanical feature for the first sensor or the second sensor. The method of claim 1, further comprising isotropic release etching the water absorbing dielectric layer selectively using a second mechanical mask to form at least one void feature for the first sensor or the second sensor. 4. The method of claim 1, further comprising growing nano wires selectively or cap bonding using a third mechanical mask to form at least one mechanical feature for the first sensor or the second sensor. The method of claim 1, wherein the first sensor and the second sensor are selected from the group consisting of an accelerometer, a junction temperature sensor, a resistive temperature sensor, a air flow sensor resistor, a hygrometer, a photo diode light sensor, a pressure sensor, a hydrogen (¾) sensor, an explosive ambient, and combination thereof, and the first sensor differs from the second sensor. 6. A multi-sensor integrated chip, comprising: a hygrometer capacitor 120 formed with a water absorbing dielectricl24 between a first hygrometer electrode 122 of a first conductive layer 112 and a second hygrometer electrode 126 of a second conductive layer 116 on a semiconductor substrate 100, wherein the first conductive layer 1 12 is closer in proximity to the semiconductor substrate 100 than the second conductive layer 116; and a suspended air flow sensor resistor 130 formed in the second conductive layer 132 over a void 136 in a lower layer of the semiconductor die. The multi-sensor integrated chip of claim 6, wherein the hygrometer capacitor includes perforations the second hygrometer electrode exposing the water absorbing dielectric. The multi-sensor integrated chip of claim 6, further comprising an accelerometer formed as variable capacitor between a movable electrode of the second conductive layer interdigitated with a fixed electrode of the second conductive layer and a void separating movable electrode from a ground plane electrode of the first conductive layer, or an accelerometer formed as variable capacitor between fixed and moving components of a release silicon substrate. The multi-sensor integrated chip of claim 6, further comprising a pressure capacitor formed with a sealed void between a first pressure electrode of the first conductive layer and a second pressure electrode of the second conductive layer. multi-sensor integrated chip, comprising: at least three different types of sensors to measure at least three different types of environmental states; an implanted doped layer 108 in a substrate 100 including at least one implanted doped feature; a first conductive layer 1 12 including at least one first conductive feature; a water absorbing dielectric layer 1 14 including at least one insulator feature; and a second conductive layer 1 16 including at least one second conductive feature, wherein each of the at least three different types of sensors includes a feature selected from the group consisting of an implanted doped feature, a first conductive feature, an insulator feature, and a second conductive feature. 1 1. The multi-sensor integrated chip of claim 10, further comprising a mechanical layer including at least one mechanical layer feature or at least one void feature formed by isotropic release etching the substrate, the first conductive layer, the water absorbing dielectric layer, or the second conductive layer selectively for at least one of the at least three different types of sensors. 12. The multi-sensor integrated chip of claim 10, wherein the at least three different types of sensors are selected from the group consisting of an accelerometer, a junction temperature sensor, a resistive temperature sensor, a air flow sensor resistor, a hygrometer, a photo diode light sensor, a pressure sensor, a hydrogen (¾) sensor, an explosive ambient, and combination thereof, and the first sensor differs from the second sensor. 13. The multi-sensor integrated chip of claim 10, further comprising at least five different types of sensors to measure at least five different types of environmental states. 14. The multi-sensor integrated chip of claim 10, wherein the substrate includes a circuit component to transduce and digitize the signals from the first sensor and the second sensor. 15. The multi-sensor integrated chip of claim 14, wherein the circuit component is selected from the group of an amplifier, an analog-to-digital converter (ADC), an digital-to-analog converter (DAC), memory, a processor, and combination thereof. |
BACKGROUND
Sensors can be used to measure motion, sound, light, temperature, humidity, air flow, ambient gases, and other environmental conditions. Sensors can be produced and manufactured in electronic chips. Typically, a single type of sensor measuring a single environmental condition is designed and packaged in a single chip, so each sensor is package separately from other types of sensors. The same type of sensor may have been designed and packaged in a single chip because semiconductor materials could be selected and optimized to the sensing function of the sensor or sensor were larger and consumed more power than other circuit on the chip. When multiple sensors are used for a particular application, a separate sensor chip may be assembled on a printed circuit board (PCB) for each type of desired measurement with the logic to process the outputs of the multiple sensors. The application may use multiple sensor chips and packages on a PCB.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view illustrating an implanted doped layer, a first conductive layer, a dielectric layer, and a second conducting layer on a semiconductor substrate in accordance with an example;
FIG. 2 is a top view illustrating a hygrometer, an air flow sensor, a resistive temperature sensor, a junction temperature sensor, a photo diode light sensor, an accelerometer, a pressure sensor, an explosive ambient, and a hydrogen sensor on a semiconductor substrate in accordance with an example;
FIG. 3 A is a cross section view illustrating a hygrometer, an air flow sensor, a resistive temperature sensor, a junction temperature sensor, and a photo diode light sensor on a semiconductor substrate in accordance with an example;
FIG. 3B is a cross section view illustrating an accelerometer, a pressure sensor, an explosive ambient, and a hydrogen sensor on a semiconductor substrate in accordance with an example;
FIG. 4 is a top view illustrating a multi-sensor integrated chip with a hygrometer and an air flow sensor in accordance with an example; and FIG. 5 is a flowchart illustrating a method for producing a multi-sensor integrated chip on a substrate in accordance with an example.
DETAILED DESCRIPTION
Alterations and further modifications of the illustrated features, and additional applications of the principles of the examples, which would occur to one skilled in the relevant art and having possession of this disclosure, are to be considered within the scope of the disclosure. The same reference numerals in different drawings represent the same element.
Producing sensors using integrated circuit (IC) technology can use many masks and fabrication processes. Each mask and process step used to produce the sensor may add additional cost to the sensor's overall costs. Applications using PCBs and many process steps can cause sensor applications to be costly.
Multiple sensors measuring different environmental conditions may be fabricated on a single die and packaged in a single chip. Integrating sensors onto a single die with processor logic and memory can eliminate printed circuit boards (PCBs) traditionally used to couple multiple sensor chips together with a processor and memory in an application. Integration can allow a single chip to sense multiple environmental conditions that were previously performed by multiple sensor chips. Including multiple sensors on a single die or packaged chip may reduce the size and cost of products utilizing sensors and may reduce the cost developing products with sensors. A multi- sensor integrated chip can provide simple low cost sensors that may be mass produced and placed in common applications. A multi-sensor integrated chip may include many desirable sensors that can be used in many different applications where the used sensors may be activated and the unused sensors can be turned off to conserve power.
Desirable sensors may include a hygrometer to measure humidity, an air flow or air speed sensor, a temperature sensor, an accelerometer to detect motion, a light intensity sensor, and sensors to detect various chemicals and gases (e.g., hydrogen). An accelerometer may sense or detect vibration, tilt, sound, direction, or motion. Integrating desirable sensors into a single multi-sensor integrated chip may eliminate costly PCBs for an application.
Environmental conditions may change the capacitance, resistance, or
semiconductor properties of materials on ICs. The electrical features, such as capacitors and resistors, may form the structures of many sensors allowing sensors be produced on ICs. Some sensors may use mechanical and electrical functions to measure
environmental conditions or states. Micro-electro-mechanical systems (MEMS) can be used with IC technology to create micro-mechanical features or sensor features on an IC.
Fabricating a multi-sensor integrated chip may use IC fabrication processes. IC fabrication can include a series of material depositions, heat treatments, masks, and etches to remove material on a semiconductor substrate or wafer. Producing or fabricating multiple sensors on a single IC may use several masks. The fabrication steps can create features that produce different types of sensors. The fabrication process may begin with a semiconductor wafer. The wafer may include silicon. As illustrated in FIG. 1, the wafer may include a silicon substrate 100 with an electrical insulator 102 separating the active devices, sensors, or devices from the substrate (called a silicon-on-insulator (SOI) wafer). The electrical insulator may be a silicon oxide (S1O 2 ). For example, the silicon 104 on the insulator may be between 10 μιη and 30 μιη thick. The silicon may be doped or implanted with elements like boron (B), phosphorous (P), arsenic (As) to change the silicon's electrical properties and may be used to create regions or wells 108 that can be used to create pn junctions used for diodes and transistors.
The elements or dopants may be used to change the electrical properties affecting current flow and direction of current flow. The elements or dopants may be deposited on the surface of the wafer by an ion implantation process. The dopants may be selectively applied to the silicon using a first mask or an implant mask and may create an implanted doped layer. The mask may be applied using photolithography. The dopants may be absorbed by the wafer and diffused through the silicon using a heat, thermal, annealing, or rapid thermal annealing (RTA) process.
A first conductive layer 1 12 may be deposited on the surface of the wafer or silicon 104. The conductive layer may be a metal or polysilicon. The metal may be aluminum (Al), gold (Au), silver (Ag), nickel (Ni), titanium (Ti), or combination thereof. The conductive layer and other layers may be deposited using physical vapor deposition (PVD), chemical vapor deposition (CVD), electrochemical deposition (ECD), molecular beam epitaxy (MBE) or atomic layer deposition (ALD). Photolithography and masks may be used to pattern the dopants, the electrically conductive layers, and the electrically insulating layers. Photolithography may be used to protect or expose a pattern to etching which can remove material from the conductive layer or insulating layers. Etching may include wet etching, dry etching, chemical-mechanical planarization (CMP), reactive-ion etching (RIE), deep reactive-ion etching (DRIE). Etching may be isotropic or anisotropic. The first conductive layer may be selectively removed or etched using a second mask, a first conductive layer mask, or a first metal mask. The resulting features of the conductive layer may create resistors, capacitor electrodes, contact pads, wires, and traces that can connect the devices and sensors together.
An insulator, dielectric, or via layer 1 14 may be deposited on the surface of exposed silicon 104 and remaining first conductive layer 112. The dielectric may have water absorbing properties that can be used in a hygrometer or humidity sensor. The dielectric may provide spacing between two electrode plates of a capacitor or may provide electrical isolation from the first conductive layer or silicon. The insulator, dielectric, or via layer may be selectively removed using a third mask, a dielectric layer mask, or a via mask.
A second conductive layer 116 may be deposited on the surface of the exposed silicon 104, the exposed first conductive layer 112, and remaining via layer 1 14. The second conductive layer may be selectively etched using a fourth mask for a second conductive layer mask or a second metal mask. The second metal may provide an upper capacitor electrode or a resistor electrically isolated from the silicon.
A fifth mask or mechanical mask may provide DRIE or release etching of the via layer or silicon layer creating a void 106 and movable MEMS components used in sensors. The mechanical mask may be used for nanowire (NW) growth or cap bonding. NW growth may include creating palladium (Pd) wires 118. Palladium wires may be used for hydrogen sensors. The cap material may protect some sensors and may be used to create sensors.
After structures and sensors are fabricated on the semiconductor wafer or silicon substrate 100, the wafer may be cut into dies that may be packaged into individual chips. Many semiconductor dies many be produced from a single wafer or substrate. A single semiconductor die may have a plurality of different types of sensors that can be packaged using packaging material to form a multi-sensor integrated chip.
The multi-sensor integrated chip or integrated sensor chip may be fabricated to include a hygrometer, an air flow sensor, a resistive temperature sensor, a junction temperature sensor, a photo diode light sensor, an accelerometer, a pressure sensor, an explosive ambient, and a hydrogen sensor. In one example, a five mask process may be used to create multiple sensors on a single wafer or semiconductor die. The five masks may be an implant mask, a first metal mask, a via mask, a second metal mask, and a mechanical mask. The multiple sensors may use a SOI substrate with doped regions forming pn junctions, a first conductive layer, a dielectric layer, a second conductive layer, and a mechanical layer. A mechanical layer may include a NW, a cap bond, a polymer, or a parylene.
FIG. 2 provides a top view illustration of a plurality sensor devices that may be included on the same semiconductor die of a multi-sensor integrated chip. FIG. 2 illustrates some of the relevant layers to the sensors. FIGS. 3A and 3B illustrate a cross section view of some the sensor devices in FIG. 2 showing five possible layers that may be used to fabricate the sensor devices on a single substrate or semiconductor die.
A hygrometer sensor may be used to measure humidity in an environment. The hygrometer 120 may be formed by a hygrometer capacitor, as illustrated in FIG. 2. A cross sectional view 220 of the layers of hygrometer capacitor is illustrated in FIG 3 A. The first conductive layer may form a first hygrometer electrode 122 and the second conductive layer may form a second hygrometer electrode 126. The water absorbing dielectric layer may form a dielectric 124, an electrical insulator, and a separation for the first hygrometer electrode and the second hygrometer electrode. The second hygrometer electrode may include perforations 128 of holes in the second hygrometer electrode that may expose the water absorbing dielectric to moisture in the environment or on the surface of the chip. The water absorbing dielectric may change dielectric properties affecting the hygrometer capacitance. The hygrometer capacitor may be referred to as a wet capacitor. A dry capacitor may be formed by sealing the water absorbing dielectric from moisture in the environment or the chip. A comparison between the wet capacitor and dry capacitor may be use to determine the humidity of the environment. The chip packaging may provide moisture ports to allow moisture to be absorbed by the hygrometer on the die in the chip.
An air flow sensor may be used to determine direction of air flow and air speed. The air flow sensor 130 may be a suspended resistor 132 over a void 136 in lower layers of the semiconductor die, as illustrated in FIGS. 2 and FIG 3 A. FIG. 2 provides a top view illustration of the air flow sensor and FIG 3 A provides a cross sectional view 230 of the layers of the air flow sensor. The suspended resistor may be formed from the first conductive layer or the second conductive layer. The lower layers below the suspended resistor can be removed through a DRIE or release etch. The lower layers may include the dielectric layer or the silicon 104 on the insulator 102. The void may be channeled to allow air flow 134 (FIG. 3) outside the chip to travel through the air flow sensor on the chip. The resistor may cool down and become less resistive with more air flow. The resistor may heat up and become more resistive with less air flow. The air flow sensor may operate in conjunction with a non-air cooled temperature sensor. The air flow sensor resistance may be compared with the non-air cooled temperature sensor. Two air flow sensors may be used to determine the direction of the air flow. A first air flow sensor may be perpendicular to a second air flow sensor. The chip packaging may provide air ports to the air flow sensor on the die in the chip.
A resistive temperature sensor may be used to determine the temperature of the environment or the temperature of the substrate. The resistive temperature sensor 140 may be a resistor 146 formed in the first conductive layer or the second conductive layer, as illustrated in FIGS. 2 and FIG 3 A. FIG. 2 provides a top view illustration of the resistive temperature sensor and FIG 3 A provides a cross sectional view 240 of the layers of the resistive temperature sensor. The resistor in the second conductive layer may be isolated from the silicon with an insulator base 144. The resistive temperature sensor may be exposed to the air or environment. A change in temperature may change the resistance of the resistor. The temperature sensor may make contact with a thermally conductive packaging material used for the chip.
A junction temperature sensor may provide another type of temperature sensor to determine the temperature of the environment or the temperature of the substrate, as illustrated in FIGS. 2 and FIG 3 A. FIG. 2 provides a top view illustration of the junction temperature sensor and FIG 3A provides a cross sectional view 242 of the layers of the junction temperature sensor. The junction temperature sensor 142 may be formed as a pn junction in an implanted doped region 148 in the silicon 104. The electrical properties or the threshold voltage of the pn junction may change with temperature. The silicon may be n+ doped and the implanted region may be p+ doped to form a pn junction.
Alternatively, the silicon may be p+ doped and the implanted region may be n+ doped to form a pn junction. The first conductive layer may provide an implanted region contact 158 with the implanted region or a silicon region contact with the silicon on the insulator 102. A resistive temperature sensor 140 and junction temperature sensor may be used in connection with other sensors on the chip to provide a baseline temperature of the device. A photo diode light sensor may be used to determine the light intensity of the environment. The photo diode light sensor 150 may be formed as a pn junction in an implanted doped region 154 in the silicon 104, as illustrated in FIGS. 2 and FIG 3A. FIG. 2 provides a top view illustration of the photo diode light sensor and FIG 3A provides a cross sectional view 250 of the layers of the photo diode light sensor. Photons from light may cause an electrical current to pass through a pn junction or diode structure forming a light sensor. The first conductive layer may provide an implanted region contact 152 with the implanted region or a silicon region contact 156 with the silicon region. The current flow may increase with light intensity. The implanted region or the common silicon-on-insulator (SOI) may be exposed to light. The chip package may provide a transparent window to allow light to pass to the implanted region or the SOI.
An accelerometer may be used to determine the force and direction on a device using the multi-sensor integrated chip. The accelerometer 160 may be formed by a comb capacitor, as illustrated in FIGS. 2 and FIG 3B. FIG. 2 provides a top view illustration of the accelerometer and FIG 3B provides a cross sectional view 260 of the layers of the accelerometer. The first conductive layer may form a ground plane electrode 162 and the second conductive layer may form a movable electrode 168 and a fixed electrode 166. The dielectric layer may form a dielectric 164, an electrical insulator, and provide a fixed separation between the ground plane electrode and the fixed electrode. The dielectric may attach the fixed electrode and mounting points of the movable electrode to the die 168B. The dielectric layer may be removed through a DRIE or release etch creating a void between the ground plane electrode and the movable electrode 168A and allow the movable electrode a range of motion. The movable electrode may include a proof mass. The movable electrode may flex relative to the mounting point of the movable electrodes. The environmental motion may create movement of the movable electrode that may change the capacitance between the movable electrode and fixed electrode and between the movable electrode and the ground plane electrode. The change in capacitance may indicate the direction of acceleration or vibration. The comb accelerometer may sense acceleration in 3 axes of direction.
A pressure sensor may be used to determine the absolute pressure or relative pressure of the environment. The pressure sensor 170 may be formed by a capacitor, as illustrated in FIGS. 2 and FIG 3B. FIG. 2 provides a top view illustration of the pressure sensor and FIG 3B provides a cross sectional view 270 of the layers of the pressure sensor. The first conductive layer may form a first pressure electrode and the second conductive layer may form a second pressure electrode diaphragm 174. The dielectric layer may form a dielectric, an electrical insulator, and a separation for the first pressure electrode and the second pressure electrode diaphragm on the perimeter of the second pressure electrode diaphragm. The dielectric layer may be removed through a DRIE or a release etch to create a void 176 between the first pressure electrode and the second pressure electrode diaphragm. The second pressure electrode diaphragm may be exposed to environmental pressure. The void may allow the second pressure electrode diaphragm to flex with changes in environmental pressure. The chip packaging may provide pressure ports to allow the pressure sensor to sense pressure on the die in the chip. In another example, a pressure sensor 172 (FIG. 2) may include perforations or holes in the second pressure electrode diaphragm to allow the dielectric layer under the second pressure electrode diaphragm to be etched for a void. The perforations may be sealed with a polymer 178 or parylene creating a near vacuum in the void between the first pressure diaphragm and the second pressure electrode diaphragm.
An explosive ambient sensor may be used to determine vapors and liquids with explosive properties (e.g., natural gas) in the environment. The explosive ambient sensor 180 may be formed by a capacitor, as illustrated in FIGS. 2 and FIG 3B. FIG. 2 provides a top view illustration of the explosive ambient sensor and FIG 3B provides a cross sectional view 280 of the layers of the explosive ambient sensor. The second conductive layer may form a first explosive ambient electrode 186 and a second explosive ambient electrode with an etched separation between the first explosive ambient electrode and the second explosive ambient electrode. The first explosive ambient electrode and the second explosive ambient electrode may be located on a dielectric 184 on the dielectric layer. The dielectric and conductive properties of various chemicals and gases may change the capacitance or resistance between the first explosive ambient electrode and the second explosive ambient electrode, which may be used to detect the presence of a particular gas or a particular chemical. The first explosive ambient electrode and the second explosive ambient electrode may be exposed to the environment to detect gases and chemicals in the environment. The chip packaging may provide a port to allow gases and chemical to contact the explosive ambient sensor on the die in the chip.
A hydrogen sensor may be used to determine hydrogen gas in the environment. A hydrogen sensor 182 may be formed by a resistor 188 which includes palladium (Pd), as illustrated in FIGS. 2 and FIG 3B. FIG. 2 provides a top view illustration of the hydrogen sensor and FIG 3B provides a cross sectional view 282 of the layers of the hydrogen sensor. The palladium may be a metal of the second conductive layer or the palladium may be nanowire (NW) growth of the mechanical layer. The palladium may be isolated from the silicon by a dielectric or insulator 184. The palladium may absorb hydrogen changing the resistive properties of the palladium. The change in resistance may provide a hydrogen sensor. The palladium resistor may be exposed to the environment and hydrogen in the environment. The chip packaging may provide a port to allow hydrogen to contact the hydrogen sensor on the die in the chip.
In another example, a multi-sensor integrated chip may include a hygrometer and an air flow sensor, as illustrated in FIG. 4. Other desirable sensors may be added or combined to provide additional sensor functionality to the multi-sensor integrated chip.
Another embodiment provides a method for producing a multi-sensor integrated chip. The method may include the operation of providing a substrate. The operation of implanting a dopant selectively on the substrate using an implant mask may follow. The next operation of the method may be annealing the dopant in the substrate forming a junction temperature sensor. The method may further include depositing a first conductive layer on the substrate. The operation of etching the first conductive layer selectively using a first conductive layer mask forming a first hygrometer electrode for a hygrometer capacitor may follow. The next operation of the method may be depositing a water absorbing dielectric layer on the substrate. The operation of etching the water absorbing dielectric layer selectively using a via mask forming an electrical insulator for the hygrometer capacitor may follow. The method may further include depositing a second conductive layer on the substrate. The operation of etching the second conductive layer selectively using a second conductive layer mask forming a second hygrometer electrode for the hygrometer capacitor and an air flow sensor resistor my follow. The next operation of the method may be isotropic release etching the water absorbing dielectric layer selectively using a first mechanical mask forming a void between a suspended air flow sensor resistor and the substrate.
Another example provides a method 500 for producing a multi-sensor integrated chip on a substrate, as shown in the flow chart in FIG. 5. The method includes the operation of implanting a dopant selectively on the substrate using an implant mask to form at least one implanted doped feature for a first sensor or a second sensor, wherein the first sensor measures a first environmental state and the second sensor measures a second environmental state different from the first environmental state, as in block 510. Implanting the dopant selectively on the silicon substrate can include annealing the dopant in the substrate. The operation of depositing a first conductive layer selectively on the substrate to form at least one first conductive feature for the first sensor or the second sensor follows, as in block 520. Depositing a first conductive layer selectively on the substrate can include etching the first conductive layer selectively using a first conductive layer mask. The next operation of the method may be depositing a water absorbing dielectric layer on the substrate to form at least one insulator feature for the first sensor or the second sensor, as in block 530. Depositing a water absorbing dielectric layer on the substrate can include etching the water absorbing dielectric layer selectively using a via mask forming an electrical insulator. The method further includes depositing a second conductive layer selectively on the substrate to form at least one second conductive feature for the first sensor or the second sensor, wherein each of the first sensor and second sensor includes at least one implanted doped feature, first conductive feature, insulator feature, or second conductive feature, as in block 540. Depositing a second conductive layer selectively on the substrate can include etching the second conductive layer selectively using a second conductive layer mask.
The method for producing a multi-sensor integrated chip on a substrate can further include isotropic release etching the substrate, the first conductive layer, the water absorbing dielectric layer, or the second conductive layer selectively using a first mechanical mask to form at least one mechanical feature for the first sensor or the second sensor. The isotropic release etching can provide features that are thermal and mechanical isolate from other features and components on the substrate. The mechanical feature may be a moving mechanical feature. For example, the moving mechanical feature in the dielectric layer or the substrate may be used in the accelerometer. A released conductive line can form the airflow sensor. Alternatively, the method can include isotropic release etching the water absorbing dielectric layer selectively using a second mechanical mask to form at least one void feature for the first sensor or the second sensor. The method can include growing nanowires selectively or cap bonding using a third mechanical mask to form at least one mechanical feature for the first sensor or the second sensor. The first sensor and the second sensor can include an accelerometer, a junction temperature sensor, a resistive temperature sensor, a air flow sensor resistor, a hygrometer, a photo diode light sensor, a pressure sensor, a hydrogen (H 2 ) sensor, an explosive ambient, or combination thereof. The first sensor differs from the second sensor. The first environmental state and the second environmental state can include humidity, air flow, air speed, air flow direction, temperature, motion, vibration, tilt, sound, motion direction, light intensity, light wavelength, light spectrum, chemical concentration, gas concentration, or combination thereof. The method can include forming a circuit component on the substrate to transduce and digitize the signals from the first sensor and the second sensor. The circuit component can include an amplifier, an analog-to-digital converter (ADC), an digital-to-analog converter (DAC), memory, a processor, or combination thereof.
Another example provides a method for producing a multi-sensor integrated chip on a substrate. The method includes the operation of implanting a dopant selectively on the substrate using an implant mask to form an implanted doped feature for a first sensor. The first sensor can measure a first environmental state. The operation of depositing a first conductive layer selectively on the substrate to form a first conductive feature for a second sensor follows. The second sensor measures a second environmental state different from the first environmental state. The next operation of the method may be depositing a water absorbing dielectric layer on the substrate to form an insulator feature for a third sensor. The third sensor measures a third environmental state different from the first and second environmental state. The method further includes depositing a second conductive layer selectively on the substrate to form a second conductive feature for a fourth sensor. The fourth sensor measures a fourth environmental state different from the first, second, and third environmental state.
The method for producing a multi-sensor integrated chip on a substrate can further include isotropic release etching the water absorbing dielectric layer selectively using a first mechanical mask to form a void feature for a fifth sensor. The fifth sensor measures a fifth environmental state different from the first, second, third, and fourth environmental state. The method can include growing nanowires selectively or cap bonding using a second mechanical mask to form a mechanical feature for a fifth sensor.
While the forgoing examples are illustrative of the principles of the present invention in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and details of implementation can be made without the exercise of inventive faculty, and without departing from the principles and concepts of the invention. Accordingly, it is not intended that the invention be limited, except as by the claims set forth below.
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