Sensor with integrated heater

Abstract

A device with a micro-electromechanical system (MEMS) sensor die includes a deformable membrane, a MEMS heating element, and a substrate. The MEMS heating element and the deformable membrane are integrated in the same layer and in the same plane. The MEMS heating element surrounds the deformable membrane and is separated from the deformable membrane by a groove. The MEMS heating element is used to generate heat to heat the deformable membrane. The substrate is coupled to the deformable membrane.

Description

[0001] Related Applications

[0002] This application is a non-provisional patent application claiming the benefit of and priority to U.S. Provisional Patent Application No. 62 / 732,325, filed on September 17, 2018, the entire disclosure of which is incorporated herein by reference. This application is a continuation-in-part non-provisional patent application claiming the benefit of and priority to U.S. Application No. 16 / 520,228, filed on July 23, 2019, the entire disclosure of which is incorporated herein by reference. This application is also a continuation-in-part non-provisional patent application claiming the benefit of and priority to U.S. Application No. 16 / 378,322, filed on April 8, 2019, the entire disclosure of which is incorporated herein by reference. Background Art

[0003] Many electronic devices are used under different conditions and are exposed to different external environments. For example, sensors may be exposed to external environments such as water, which may damage sensitive components in addition to causing degradation of sensor performance. However, sensors are sensitive to these external environments, such as water droplets on the membrane, which may cause offsets and thus degradation of performance. In addition, electronic devices can be used under different temperature conditions. However, due to the influence of temperature-related parameters such as the temperature coefficient of offset (TCO), the performance of the sensor will change after it is mounted on the board (for example, soldered to a printed circuit board (PCB)). Some attempts have been made in the prior art to solve the problem of performance degradation, such as using calibration algorithms to compensate for temperature effects before the sensor is installed and therefore soldered on the board. However, using a calibration algorithm before soldering the sensor does not solve or compensate for the offset of the temperature coefficient that occurs after soldering the sensor. Summary of the invention

[0004] Therefore, it is necessary to calibrate the sensor after it is soldered to the board to account for the shift in the temperature coefficient. In addition, when liquid is detected, it is necessary to handle and remove the liquid from the sensor environment.

[0005] In some embodiments, the present application provides a device having a sensor die of a microelectromechanical system (MEMS), which includes a deformable membrane, a MEMS heating element, and a substrate. The MEMS heating element is integrated with the deformable membrane in the same layer and in the same plane. The MEMS heating element surrounds the deformable membrane and is separated from the deformable membrane by a groove. The MEMS heating element is used to generate heat to heat the deformable membrane. The substrate is coupled to the deformable membrane.

[0006] In some embodiments, the trench is located within the passivation layer. It should be understood that the material within the trench is selected from the group consisting of silicon nitride and silicon oxide.

[0007] In some embodiments, the device includes a second groove. The groove is arranged between the MEMS heating element and the deformable membrane, and the second groove is arranged at the outer periphery of the MEMS heating element for electrically isolating the MEMS heating element from the peripheral layer. It should be understood that the second groove is arranged between the peripheral layer and the MEMS heating element.

[0008] In some embodiments, the outer periphery of the deformable membrane is disposed on the oxide layer. The deformable membrane, the oxide layer and the substrate form a cavity, and the substrate includes an electrode formed on an upper surface of the substrate, and the upper surface of the substrate faces the deformable membrane in the cavity. According to some embodiments, the MEMS heating element is disposed on the oxide layer.

[0009] It will be appreciated that in some embodiments, the MEMS heating element is used to generate heat for calibration after the MEMS sensor die is soldered to the board in response to an offset temperature coefficient (TCO). In another embodiment, the MEMS heating element is used to generate heat in response to detecting the presence of liquid on the deformable membrane.

[0010] In some embodiments, the present application provides a device including a MEMS sensor die, which includes a deformable membrane, a MEMS heating element and a substrate. The MEMS heating element is integrated with the deformable membrane in the same layer and in the same plane. The MEMS heating element is located at the periphery of the deformable membrane for generating heat to heat the deformable membrane. The substrate is coupled to the deformable membrane. It should be understood that the deformable membrane can be formed by a polycrystalline silicon / single crystal silicon layer.

[0011] In some embodiments, the device further comprises another MEMS heating element, the other MEMS heating element and the deformable membrane are located in the same layer and in the same plane. The MEMS heating element is separated from the other MEMS heating element. The other MEMS heating element is located at the periphery of the deformable membrane and is used to generate heat to heat the deformable membrane.

[0012] In some embodiments, the MEMS heating element has a gap therein. The MEMS heating element surrounds the deformable membrane but does not completely enclose the deformable membrane.

[0013] It should be understood that in some embodiments, the device further comprises a groove disposed between the MEMS heating element and the deformable membrane. In some embodiments, the groove comprises a passivation layer. In some embodiments, the device further comprises another groove disposed at the outer periphery of the MEMS heating element and used to electrically isolate the MEMS heating element from the peripheral layer. Another groove may be disposed between the peripheral layer and the MEMS heating element.

[0014] It should be understood that in some embodiments, the device further comprises a trench disposed between the MEMS heating element and the deformable membrane. The material within the trench is selected from the group consisting of silicon nitride and silicon oxide.

[0015] In some embodiments, the outer periphery of the deformable membrane is disposed on the oxide layer. The deformable membrane, the oxide layer and the substrate form a cavity. The substrate includes an electrode formed on the upper surface of the substrate, and the upper surface of the substrate faces the deformable membrane in the cavity. The MEMS heating element is disposed on the oxide layer.

[0016] The MEMS heating element may be used to generate heat for calibration in response to the TCO after the MEMS sensor die is soldered to the board. It will be appreciated that in some embodiments, the MEMS heating element may be used to generate heat in response to detecting the presence of liquid on the deformable membrane.

[0017] In some embodiments, the present application provides a device having a sensor die, which includes a deformable membrane, a substrate coupled to the deformable membrane, and a heating element, the heating element being located at the periphery of the deformable membrane and within the sensor die. The heating element is used to heat the deformable membrane.

[0018] In some embodiments, the heating element has a gap inside.It should be understood that in some embodiments, the heating element surrounds the deformable membrane but does not completely surround the deformable membrane.

[0019] In some embodiments, the device further comprises a groove disposed between the heating element and the deformable membrane. The groove comprises a passivation layer.

[0020] In some embodiments, the device further comprises another groove, which is arranged on the outer periphery of the heating element and is used to electrically isolate the heating element from the peripheral layer. It should be understood that another groove can be arranged between the peripheral layer and the heating element.

[0021] In some embodiments, the periphery of the deformable membrane is disposed on the oxide layer. It should be understood that the deformable membrane, the oxide layer and the substrate form a cavity. The substrate includes an electrode formed on an upper surface of the substrate, and the upper surface of the substrate faces the deformable membrane in the cavity. It should be understood that the heating element can be disposed in the same layer as the oxide layer, for example, on the oxide layer or in the oxide layer.

[0022] It will be appreciated that the heating element is used to generate heat for calibration in response to the TCO after the sensor die is soldered to the board. In some embodiments, the heating element is used to generate heat in response to detecting the presence of liquid on the deformable membrane.

[0023] These and other aspects of the concepts described in this application may be better understood in conjunction with the following drawings, description and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1A-1B A top view and a cross-sectional view of a sensor with an integrated heater provided by some embodiments are shown.

[0025] Figure 2 A schematic diagram of a sensor device integrated with a heater provided by some embodiments is shown, wherein the heater is used to heat to evaporate water droplets on a deformable membrane.

[0026] Figure 3 A schematic diagram of a sensor device integrated with a heater provided by some embodiments is shown.

[0027] Figure 4 A schematic diagram of a sensor device integrated with a heater provided by some embodiments is shown.

[0028] Figure 5 A schematic diagram of a sensor device integrated with a heater provided by some embodiments is shown.

[0029] Figure 6A-6B A top view of a sensor integrated with different heater structures provided by some embodiments is shown. DETAILED DESCRIPTION

[0030] Before describing various embodiments in detail, it should be understood by those skilled in the art that these embodiments are not restrictive, because the elements in these embodiments can be varied. It should also be understood that the specific embodiments described and / or illustrated in this application have some elements that can be separated from the specific embodiment and can be combined with any one of the other embodiments described in this application or replace the elements in any one of the embodiments.

[0031] Those skilled in the art should also understand that the terms used here are to describe certain concepts, rather than to limit. Unless otherwise specified, serial numbers (such as the first, second, third, etc.) are used to distinguish or identify different elements or steps in a component or step, and do not provide sequence or numerical restrictions for the elements or steps of these embodiments. For example, "first", "second", and "third" elements or steps do not necessarily have to appear in this order, and these embodiments are not necessarily limited to three elements or steps. It should also be understood that, unless otherwise specified, any term such as "left", "right", "front", "back", "top", "middle", "bottom", "forward", "reverse", "clockwise", "counterclockwise", "up", "down", or other similar terms such as "high", "low", "above", "below", "vertical", "horizontal", "proximal", "distal", "periphery", "outside", etc. are only for the convenience of description, and are not intended to imply any specific fixed position, pointing or direction, etc. On the contrary, these terms are only used to represent relative position, pointing or direction, etc. It should also be understood that unless the context clearly indicates otherwise, the singular "one", "a kind of" and "the" include plural forms.

[0032] Unless otherwise defined, all technical and scientific terms used in the embodiments of the present application have the same meanings as understood by those skilled in the art.

[0033] Many electronic devices are used under different conditions and are exposed to different external environments. For example, sensors may be exposed to external environments such as water, which may damage sensitive components in addition to causing possible degradation of sensor performance. However, sensors are sensitive to these external environments, for example, water droplets on the membrane may cause an offset, resulting in performance degradation. In addition, electronic devices can be used under different temperature conditions. However, due to the influence of temperature-related parameters such as the offset temperature coefficient (TCO), the performance of the sensor will change after it is mounted on the board (for example, soldered to a printed circuit board (PCB)). Some attempts have been made in the prior art to solve the problem of performance degradation, such as using calibration algorithms to compensate for temperature effects before the sensor is installed and therefore soldered on the board. However, using a calibration algorithm before soldering the sensor does not solve or compensate for the offset of the temperature coefficient that occurs after soldering the sensor.

[0034] Therefore, it is necessary to calibrate the sensor after it is soldered to the board to account for the temperature coefficient shift. In addition, when liquid is detected, it is necessary to handle and remove the liquid from the sensor environment.

[0035] Next, refer to Figure 1A-1B Some embodiments shown provide a top view and a cross-sectional view of a sensor with an integrated heater. Figure 1AAs shown, the deformable membrane 110 is surrounded by a heating element 120. It should be understood that the sensor device can be a micro-electromechanical system (MEMS) sensor die. The MEMS sensor die includes a deformable membrane 110, a substrate 140, an oxide 150, an electrode 170, a heating element 120, grooves 112-113 and a peripheral layer 180, such as a polysilicon layer. The heating element 120 is generally referred to as a heater, a MEMS heater, etc. in this application. The heater 120 can be integrated with the deformable membrane 110 on the same layer and in the same plane ( Figure 1B 1 and 12. The present invention further illustrates this point. It should be understood that in some embodiments, the heater 120 can be separated from the deformable membrane 110 and the peripheral layer 180 by the grooves 112-113. In some embodiments, the substrate 140 can include silicon. In another embodiment, the substrate can be a CMOS substrate provided with circuits. It should be understood that the inner groove 112 (i.e., at the inner periphery) electrically isolates the heater 120 from the deformable membrane 110, while the outer groove 113 (i.e., at the outer periphery) electrically isolates the heater 120 from the peripheral layer 180. It should be understood that the heater 120 can be composed of a silicon ring surrounding the deformable membrane 110. The deformable membrane 110 can be formed of a polysilicon layer.

[0036] The heater 120 may be coupled to a heater pad 122 to power the heater 120. It should be understood that the heater 120 is used to generate heat to heat the deformable membrane 110. In some embodiments, after the MEMS sensor die is soldered to the board, the heater 120 generates heat for calibration in response to the TCO. For example, when an offset is detected, the heater 120 may increase the temperature by increments of 10°C for calibration. It should be understood that increasing the temperature by 10°C is for illustrative purposes and should not be construed as limiting the embodiments. For example, the heater 120 may be used to increase the temperature by increments of 5°C. It should be further understood that the calibration is performed in response to a trigger (e.g., a user request, a threshold being met, etc.). For example, the trigger may be a signal generated in response to detecting the presence of liquid on the deformable membrane, in response to measuring an offset, in response to measuring a temperature difference between the MEMS device and the substrate that is greater than a threshold amount, etc.

[0037] In some embodiments, the heater 120 can be used to generate heat in response to detecting the presence of liquid (such as water droplets) on the deformable membrane. For example, in some embodiments, the heater 120 can be heated to a temperature of 100° C. or slightly above 100° C. to heat the deformable membrane 110 and evaporate the water droplets on the deformable membrane 110. Therefore, any offset associated with the presence of water droplets can be resolved by evaporation. It should be further understood that the presence of water is only for illustrative purposes and should not be construed as limiting the embodiments. For example, these embodiments are also applicable to other forms of liquids, such as oil. It should be understood that the embodiments provided in the present application can be applied to sensor devices that seek to resolve liquid interference, such as described in U.S. Patent Application No. 16 / 520,228 and U.S. Patent Application No. 16 / 378,322, both of which this application claims the benefit and priority of, and the entire disclosure of which is incorporated by reference into this application.

[0038] See Figure 1B Some of the embodiments shown provide a side view of a sensor with an integrated heater. It should be understood that the deformable membrane 110, the heater 120 and the grooves 112-113 are Figure 1A . In this embodiment, the heater 120 is located in the same layer and in the same plane as the deformable membrane 110. In this embodiment, the heater 120 is located in the same layer and in the same plane as the peripheral layer 180. According to some embodiments, the heater 120 and the peripheral layer 180 are deposited on the oxide layer 150. In some embodiments, the heater 120 and the deformable membrane 110 include polysilicon. In addition, it should be understood that the periphery of the deformable membrane 110 can be coupled to the upper surface of the oxide layer 150. It should be understood that the oxide layer 150 can be formed on a substrate 140, such as a silicon substrate. Therefore, the deformable membrane 110, the oxide layer 150 and the substrate 140 form a cavity 160. The deformable membrane 110 can be deflected in response to a stimulus (such as pressure). In some embodiments, the electrode 170 can be formed on the upper surface of the substrate 140, and the upper surface of the substrate 140 is disposed at the bottom of the cavity 160 and faces the deformable membrane 110. The deformable membrane 110 may also include an electrode (not shown) located thereon or integrated therein. The electrodes on the deformable membrane and the electrode 170 form a capacitor. In this way, the deflection of the deformable membrane 110 can change the charge on the electrodes of the capacitor.

[0039] It should be understood that in some embodiments, the groove 112 is located in the passivation layer. It should be understood that in some embodiments, the groove 112 can be deposited using certain materials such as silicon nitride, silicon oxide, etc., such as the inner groove and outer groove described above. For example, the inner groove is a groove disposed between the deformable membrane 110 and the heater 120, and the outer groove is a groove disposed between the heater 120 and the peripheral layer 180.

[0040] It should be understood that the heater 120 and the surrounding sensor film are arranged in the same layer, such as single crystal silicon. Therefore, there is no need to use any adjacent metal structure layer, thereby reducing the metal stress effect. In addition, the use of the heater 120 enables the device to be calibrated after the sensor is soldered to the board or during the entire service life. It should also be understood that the heater 120 mentioned above uses a principle of discharging liquid, for example, by evaporating liquids such as water or oil. In addition, it should be understood that the heater 120 mentioned above surrounds the deformable membrane 110, thereby providing a uniform temperature for the deformable membrane 110. However, it should be understood that in some embodiments, the heater 120 may include multiple heaters separated by internal gaps, or the heater 120 may not completely surround and surround the deformable membrane 110. Therefore, the heater 120 surrounding and surrounding the deformable membrane 110 is only for illustrative purposes and should not be regarded as limiting the scope of the embodiment. It should be understood that the arrangement of other structures will be described in the following figures. It should also be understood that in some embodiments, while the heater 120 is used to heat the sensor 101 (i.e., a MEMS device, such as a pressure sensor), another heater (not shown) can be used to heat the substrate 140, so that the heater 120 can selectively fine-tune the temperature of the MEMS device by heating the deformable membrane 110 and reduce the temperature difference between the substrate 140 and the MEMS device 101. It should be understood that the calibration can be performed in response to a trigger (e.g., a user request, a threshold being met, etc.). For example, the trigger can be a signal generated in response to detecting the presence of liquid on the deformable membrane, in response to measuring an offset, in response to measuring a temperature difference between the MEMS device and the substrate that is greater than a threshold amount, etc.

[0041] Figure 2 A schematic diagram of a sensor device integrated with a heater provided by some embodiments is shown, wherein the heater is used to heat to evaporate water droplets on a deformable membrane. Figure 2 and Figure 1A-1B Basically similar. In this embodiment, a water droplet 190 is formed on the deformable membrane 110, causing deflection and causing performance problems. It should be understood that through this device, the presence of the water droplet 190 can be detected. Therefore, the heating element 120 can start to heat to 100°C or slightly above 100°C to heat the deformable membrane 110, thereby evaporating the water droplet 190, so as to solve the deflection caused by the water droplet 190.

[0042] See now Figure 3 , Figure 3 Another sensor device with an integrated heater provided by some embodiments is shown. Figure 3 and Figure 1A-2However, in this embodiment, the heater 120 is integrated into the oxide layer 150, rather than being in the same layer and plane as the deformable membrane 110 or the peripheral layer 180. In other words, the heater 120 is integrated into the oxide layer 150 and is located below the peripheral layer 180 and the deformable membrane 110.

[0043] See now Figure 4 , Figure 4 Another sensor device with an integrated heater provided by some embodiments is shown. In this embodiment, Figure 4 Except that the lower surface of the heater 120 is in direct contact with the upper surface of the substrate 140, the other Figure 3 resemblance.

[0044] See now Figure 5 , Figure 5 Still another sensor device integrated with a heater provided by some embodiments is shown. Figure 5 Except that at least one end of the heater 120 is exposed in the cavity 160, the other Figure 4 In this case, when the heater 120 is heated, the cavity 160 is also heated, thereby heating the deformable membrane 110 .

[0045] See now Fig. 6A , Fig. 6A A top view of a sensor with different integrated heater structures provided by some embodiments is shown. In this embodiment, four heaters are used, for example, a plurality of heaters 620. The plurality of heaters 620 are separated from each other by gaps or grooves 612. The deformable membrane 110 is surrounded by an inner crystalline silicon layer 630a. It should be understood that the use of a crystalline silicon layer is for illustrative purposes and should not be construed as a limitation on embodiments of the present application. For example, a polycrystalline silicon layer may be used. The groove 612 separates the plurality of heaters 620 from the inner crystalline silicon layer 630a and the deformable membrane 110. It should be understood that the groove 612 also separates the plurality of heaters 620 from the outer crystalline silicon layer 630b to ensure electrical isolation from the peripheral layer (not shown here).

[0046] See now Figure 6B , Figure 6B A top view of another sensor with a different heater structure provided by some embodiments is shown. In this embodiment, a heater 620 is used, which substantially surrounds the deformable membrane 110, but does not completely surround it. Therefore, the two ends of the heater 620 are separated from each other by a gap or groove. The groove 616 separates the heater 620 from the inner crystalline silicon layer 630a, and the groove 618 separates the heater 620 from the outer crystalline silicon layer 630b. The grooves 612, 616 and / or 618 can be formed on the passivation layer and can include materials such as silicon nitride, silicon oxide, etc.

[0047] Fig. 6A and Figure 6B It is explained that the heater can have any shape or form. That is, the specific shape or number of the heater used is for illustrative purposes only and should not be construed as a limitation of the embodiment. Therefore, the sensor can be calibrated after being soldered to the board to account for the offset of the temperature coefficient. In addition, when liquid is detected, the liquid can be removed from the sensor environment by heating the heating element to heat the deformable membrane, thereby addressing any offset caused by the presence of the liquid. It should be understood that the calibration can be performed in response to a trigger (e.g., a user request, meeting a certain threshold, etc.). For example, the trigger can be a signal generated in response to detecting the presence of liquid on the deformable membrane, in response to measuring an offset, in response to measuring a temperature difference between the MEMS device and the substrate that is greater than a threshold amount, etc.

[0048] Although these embodiments have been described or illustrated by specific examples, and these embodiments or example descriptions have been quite detailed, it is not the intention of the applicant to restrict or limit the scope of these embodiments in any way. It is obvious to those skilled in the art that these embodiments are further adjusted and / or improved, and in their broader aspects, these embodiments may include these adjustments and / or improvements. Therefore, without departing from the scope of the concepts described in the present application, modifications may be made to the above-mentioned embodiments or examples. The above-mentioned embodiments and other embodiments should all be included in the scope of protection of the appended claims.

Claims

1. A device, characterized in that: include: Micro-electromechanical systems (MEMS) sensor dies, The micro-electromechanical system sensor die comprises: a deformable membrane; and A MEMS heating element integrated in the same layer and in the same plane as the deformable membrane; Wherein, the MEMS heating element is arranged on the outer periphery of the deformable membrane; The MEMS heating element is electrically isolated from the deformable membrane by the groove; The MEMS heating element is used to generate heat to heat the deformable membrane; The outer periphery of the deformable membrane is positioned on the oxide layer, the deformable membrane, the oxide layer and the substrate form a cavity, the substrate comprises an electrode formed on the upper surface of the substrate, and the upper surface of the substrate faces the deformable membrane in the cavity.

2. The device according to claim 1, characterized in that The trench is located in the silicon layer.

3. The device according to claim 1, characterized in that The material within the trench is selected from the group consisting of silicon nitride and silicon oxide.

4. The device according to claim 1, characterized in that Also includes: Another trench is positioned at an outer periphery of the MEMS heating element for electrically isolating the MEMS heating element from an outer peripheral layer.

5. The device according to claim 1, characterized in that The MEMS heating element is disposed on the oxide layer.

6. The device according to claim 1, characterized in that The MEMS heating element is used to generate heat for calibration in response to an offset temperature coefficient (TCO).

7. The device according to claim 6, characterized in that In response to a trigger, the calibration is performed.

8. The device according to claim 1, characterized in that The MEMS heating element is configured to generate heat in response to detecting the presence of liquid on the deformable membrane.

9. A device having a micro-electromechanical system (MEMS) sensor die, characterized in that: include: Deformable membrane; a MEMS heating element integrated in the same layer and in the same plane as the deformable membrane, wherein the MEMS heating element is disposed at the periphery of the deformable membrane and is used to generate heat to heat the deformable membrane; and substrate; The outer periphery of the deformable membrane is arranged on the oxide layer, the deformable membrane, the oxide layer and the substrate form a cavity, the substrate includes an electrode formed on the upper surface of the substrate, the upper surface of the substrate faces the deformable membrane in the cavity, and the MEMS heating element is arranged on the oxide layer.

10. The device according to claim 9, characterized in that Also includes: Another MEMS heating element is integrated with the deformable membrane in the same layer and the same plane, wherein the MEMS heating element and the another MEMS heating element are separated from each other, and the another MEMS heating element is arranged at the periphery of the deformable membrane and is used to generate heat to heat the deformable membrane.

11. The device according to claim 9, characterized in that The MEMS heating element has a gap therein, wherein the MEMS heating element surrounds the deformable membrane but does not completely surround the deformable membrane.

12. The device according to claim 9, characterized in that Also includes: A trench is disposed between the MEMS heating element and the deformable membrane, wherein a material within the trench is selected from the group consisting of silicon nitride and silicon oxide.

13. The device according to claim 9, characterized in that The deformable membrane and the peripheral layer each include a polysilicon layer.

14. The device according to claim 9, characterized in that The MEMS heating element is used to generate heat for calibration after the MEMS sensor die is soldered to the board in response to the offset temperature coefficient (TCO).

15. The device according to claim 9, characterized in that The MEMS heating element is configured to generate heat in response to detecting the presence of liquid on the deformable membrane.

16. A sensor die, characterized in that: include: Deformable membrane; substrate; as well as a heating element disposed at the periphery of the deformable membrane, wherein the heating element is used to heat the deformable membrane; Among them, the outer periphery of the deformable membrane is arranged on the oxide layer, the deformable membrane, the oxide layer and the substrate form a cavity, the substrate includes an electrode formed on the upper surface of the substrate, the upper surface of the substrate faces the deformable membrane in the cavity, and the heating element is arranged in the oxide layer.

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