On-chip signal paths with electrical and physical connections

Abstract

An example microelectromechanical system (MEMS) device includes a plurality of stacked layers including at least one layer including a microelectromechanical component responsive to a force to be measured. Two of the layers can include respective first and second external electrical connection points. A plurality of conductive paths can be disposed in a continuous manner on an external surface of each of the plurality of layers between the first and second external electrical connection points.

Description

BACKGROUND

[0001] Numerous items such as smartphones, smartwatches, tablets, automobiles, aerial drones, appliances, aircraft, athletic aids, and game controllers use sensors (e.g., motion sensors, pressure sensors, temperature sensors, etc.) during their operation. In commercial applications, microelectromechanical (MEMS) devices or sensors such as accelerometers and gyroscopes capture complex movements and determine orientation or direction. For example, smartphones are equipped with accelerometers and gyroscopes to enhance navigation systems that rely on global positioning system (GPS) information. In another example, aircraft determine orientation based on gyroscopic measurements (e.g., roll, pitch, and yaw) and vehicles implement assisted driving to improve safety (e.g., to identify skidding or rollover situations).

[0002] As more and more products incorporate MEMS technology for various applications, MEMS devices must be integrated with multiple shape factors and in miniaturized devices. MEMS devices can typically include numerous components and systems such as microelectromechanical components, analog and digital circuitry, and other associated processing circuitry for computing outputs based on signals associated with the microelectromechanical components. Furthermore, these components need to be protected from external environments, packaged, and interconnected with other components. The resulting MEMS devices, while very small, still occupy valuable space within the end-use device. SUMMARY

[0003] In some embodiments of the present disclosure, a microelectromechanical (MEMS) device can include a first layer, a second layer, and a third layer coupled between the first layer and the second layer, where the third layer includes one or more MEMS components. The MEMS device can also include a first plurality of electrical connection points at an exterior surface of the first layer and a second plurality of electrical connection points at an exterior surface of the second layer. The MEMS device can further include a plurality of conductive paths, where each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of connection points, and where each conductive path is disposed over the exterior surface of the first layer, the exterior surface of the second layer, and the exterior surface of the third layer.

[0004] In some embodiments of the disclosure, a MEMS device can include a plurality of layers, where at least one of the plurality of layers includes one or more MEMS components. The MEMS device can also include a first plurality of electrical connection points at a first planar exterior surface of a first layer of the plurality of layers and a second plurality of electrical connection points at a second planar exterior surface of a second layer of the plurality of layers. The MEMS device can also include a plurality of conductive paths over the first planar exterior surface and the second planar exterior surface, where each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of electrical connection points, and where each of the plurality of conductive paths extends along a third planar exterior surface of one or more layers of the plurality of layers between the first planar exterior surface and the second planar exterior surface.

[0005] In some embodiments of the disclosure, a method for operating a MEMS device in an end use device can include receiving a plurality of signals from the MEMS device at a first subset of a first plurality of electrical connection points, where the MEMS device includes a plurality of layers, where at least one of the plurality of layers includes one or more MEMS components, and where the first plurality of electrical connection points are located at a first planar exterior surface of a first layer of the plurality of layers. The method can also include providing the plurality of signals from the MEMS device to a first subset of a second plurality of electrical connection points via a first subset of a plurality of conductive paths, where each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of connection points. The method can also include receiving a plurality of signals from the end use device at a second subset of the second plurality of electrical connection points, where the second plurality of electrical connection points are located at a second planar exterior surface of a second layer of the plurality of layers. The method can also include providing the plurality of electrical signals from the end use device to a second subset of the first plurality of electrical connection points via a second subset of the plurality of conductive paths, where, for each of the conductive paths, the continuous portion of material includes a right angle between the respective first electrical connection point and the respective second electrical connection point. BRIEF DESCRIPTION OF DRAWINGS

[0006] The above-described and other features, nature, and various advantages of the disclosure will be more apparent from the following detailed description considered in connection with the accompanying drawings, in which:

[0007] Figure 1 An example motion sensing system is shown in accordance with some embodiments of the disclosure;

[0008] Figure 2 An example MEMS device with a continuous portion of material between connection points is depicted in accordance with some embodiments of the disclosure;

[0009] Figure 3 An example MEMS device with a continuous portion of material between connection points is depicted in accordance with some embodiments of the disclosure;Figure 2 an exemplary top view and front view of an exemplary MEMS device of

[0010] Figure 4 depicts an exemplary perspective view of an exemplary MEMS device in accordance with some embodiments of the disclosure Figures 2-3 an exemplary perspective view of an exemplary MEMS device of

[0011] Figure 5 depicts exemplary steps for fabricating a MEMS device having a continuous portion of material between connection points in accordance with some embodiments of the disclosure. DETAILED DESCRIPTION

[0012] MEMS devices are fabricated using semiconductor processes and include multiple stacked layers that are bonded together. One or more of the layers include a microelectromechanical assembly that responds to a force of interest (e.g., linear acceleration, angular velocity, pressure, magnetic force, ultrasonic force, etc.) by moving in response to the force and measuring the movement to generate an output signal and / or modifying an electrical signal in response to the force. The microelectromechanical assembly is packaged within the other layers of the MEMS device. One or more of the layers of the MEMS device include circuitry (e.g., filtering, scaling, etc.) that processes the signal generated by the microelectromechanical assembly. The generated output signal is provided to an external surface of the MEMS device for transmission to other components of an end-use device for additional processing. In addition, the MEMS device also receives input signals (e.g., power signals, ground, clock signals, control signals to modify register values, data lines for communication, etc.). These input signals are received via the external surface of the MEMS device.

[0013] In embodiments of the disclosure, a layer of the MEMS device can include a MEMS layer that includes the microelectromechanical assembly and a cap and substrate layer that encapsulates the MEMS layer. One of these layers can include a plurality of electrical connection points on an external surface thereof from which input signals are distributed within the MEMS device and to which output signals are provided from within the MEMS device (e.g., “internal connection points”). Another layer of the MEMS device can include a plurality of electrical connection points for connection to other components of an end-use device (e.g., “external connection points”). A conductive path can be formed on the external surface of the MEMS device between the internal connection points and the external connection points.

[0014] Each conductive path between an internal connection point and an external connection point can be formed by a single continuous portion of material, such as copper (Cu), gold (Au), nickel (Ni), cobalt (Co), tin (Sn), or combinations thereof. The conductive path can extend along multiple planar surfaces that intersect at angles, such as 90° angles. For example, the conductive path can extend along a first external planar surface that includes the internal connection point and be patterned to traverse an angled intersection between the first external planar surface and a second external planar surface. The conductive path can extend along at least a portion of the second external surface, and in some embodiments, along additional angled intersections and at least a portion of an external surface to form an electrical connection with the external connection point.

[0015] In embodiments, an internal connection point can be located on a horizontally extending shelf (e.g., in an x-y plane) of an external surface of a substrate layer. A conductive path can extend along the shelf until the shelf intersects a vertically upright external surface (e.g., in a y-z plane) of the MEMS device (e.g., of the substrate layer or of a MEMS layer). The conductive path can extend as a continuous portion of material over a 90° angle between the horizontally extending shelf and the vertically external surface, and further extend in a generally vertical direction (e.g., a positive z-axis direction) along the vertically external surface. The vertically external surface can include an external surface of the MEMS layer and an external surface of a cap layer above the MEMS layer. The conductive path can extend over the external surface of the MEMS layer and the external surface of the cap layer (e.g., in a y-z plane perpendicular to the horizontally extending shelf) until they reach an upper external horizontal surface of the cap layer. The upper external horizontal surface of the cap layer can form a vertical ledge with the vertically external surface over which the conductive path can extend as a continuous portion of material (e.g., in an x-y plane of the cap layer parallel to the shelf) such that the conductive path can also extend over the upper external horizontal surface.

[0016] The external connection points can be located above the upper outer horizontal surface of the cap layer. At least one of the external connection points can provide a ground signal, for example, that extends into the cap layer. Conductive paths can also extend along the upper outer horizontal surface of the cap layer to connect to the external connection points and result in a continuous portion of conductive material extending directly between the respective internal connection points and the external connection points. The external connection points can then be connected to other circuitry of an end-use device. Solder couplings can be formed on the external connection points for direct soldering to external components, such as circuit boards that route input and output signals between the MEMS device and other components of an end-use device. In some embodiments, the solder couplings can be distributed in a particular manner (e.g., uniformly or other pattern) in order to also facilitate physical connections between the MEMS device and external components. The solder couplings can thus form both physical and electrical connections between the MEMS device and other components, such that no additional physical connections are needed or the solder couplings form the primary physical connections between the MEMS device and external circuitry.

[0017] Figure 1 An exemplary motion sensing system 10 according to some embodiments of the present disclosure is depicted. While specific components are depicted in Figure 1 it will be understood that other suitable combinations of sensors, processing components, memory, and other circuitry can be used as needed for different applications and systems. In embodiments as described herein, the motion sensing system can include at least a MEMS device 12 and supporting circuitry, such as processing circuitry 14 and memory 16. In some embodiments, one or more additional MEMS devices 18 (e.g., MEMS gyroscopes, MEMS accelerometers, MEMS microphones, MEMS pressure sensors, and compasses) can be included within the motion processing system 10 to provide an integrated motion processing unit ("MPU") (e.g., including 3-axis MEMS gyroscope sensing, 3-axis MEMS accelerometer sensing, microphones, pressure sensors, and compasses).

[0018] The processing circuitry system 14 may include one or more components that provide necessary processing based on the requirements of the motion processing system 10. In some embodiments, the processing circuitry system 14 may include hardware control logic integrated within the sensor chip (e.g., on the substrate or cover of the MEMS device 12 or other MEMS device 18, or on a portion of the chip adjacent to the MEMS device 12 or other MEMS device 18) to control the operation of the MEMS device 12 or other MEMS device 18 and perform aspects of the processing of the MEMS device 12 or other MEMS device 18. In some embodiments, the MEMS device 12 and other MEMS devices 18 may include one or more registers that allow modification of aspects of the operation of the hardware control logic (e.g., by modifying the values ​​of the registers). In some embodiments, the processing circuitry system 14 may also include a processor, such as a microprocessor, that executes software instructions, for example, stored in memory 16. The microprocessor can control the operation of the MEMS device 12 and process signals received from the MEMS device 12 by interacting with the hardware control logic. The microprocessor can interact with other sensors in a similar manner.

[0019] Although in some embodiments ( Figure 1 (Not depicted) MEMS device 12 or other MEMS device 18 can communicate directly with external circuitry (e.g., via sensor output). End While the control input can be connected via a serial bus or directly, in some embodiments, the processing circuitry 14 can process data received from MEMS device 12 and other MEMS devices 18 and communicate with external components via communication interface 20 (e.g., SPI or I2C bus, or, in automotive applications, Controller Area Network (CAN) or Local Interconnect Network (LIN) bus). The processing circuitry 14 can convert signals received from MEMS device 12 and other MEMS devices 18 into appropriate units of measurement (e.g., based on settings provided by other computing units communicating via communication bus 20) and perform more complex processing to determine measurements such as orientation or Euler angle, and in some embodiments, determine from sensor data whether a specific activity (e.g., walking, running, braking, slipping, rolling, etc.) is occurring.

[0020] In some embodiments, certain types of information can be determined based on data from multiple MEMS devices in a process known as sensor fusion. By combining information from various sensors, it becomes possible to accurately determine information useful in a wide range of applications, such as image stabilization, navigation systems, automotive control and safety, dead reckoning, remote control and gaming devices, motion sensors, 3D cameras, industrial automation, and many others.

[0021] Each MEMS device or combination of MEMS devices can include a microelectromechanical component (e.g., of a MEMS layer) encapsulated between other layers such as a cap layer and a substrate layer. For example, the MEMS layer can include a microelectromechanical component that responds to a force of interest in a way that generates a signal that is processed by the MEMS device (e.g., by circuitry within a substrate layer such as a CMOS substrate layer or by a bonded handle layer of the MEMS device) to generate an output signal such as an analog or digital signal representing a sensed motion, a status signal, a data signal, and a control signal. The MEMS device is also supplied with input signals from external devices such as power signals, ground, clock signals, register control signals, and data lines.

[0022] Figure 2 Example MEMS devices having a continuous portion of material between connection points are depicted in accordance with some embodiments of the disclosure. While it should be understood that MEMS devices can include multiple MEMS device types fabricated with different semiconductor layers, in the example embodiments of Figure 2 In example embodiments of the inertial MEMS sensor 202, the MEMS device 202 can include a cap layer 204, a MEMS layer 206, and a substrate (e.g., CMOS) layer 208. The example inertial MEMS sensor 202 can include a movable electromechanical component (e.g., a suspended spring-mass system) within the MEMS layer 206 that is encapsulated within a volume by the cap layer 204 and the substrate layer 208.

[0023] Movement of the electromechanical component can be sensed (e.g., by capacitive sensing, piezoelectric sensing, etc.) and a signal corresponding to the movement can be routed on and / or through the MEMS sensor 202 to an external surface of the MEMS sensor 202. In example embodiments of the inertial MEMS sensor 202, the signal can be routed through the substrate (e.g., CMOS) layer 208 to an external shelf of the substrate layer 208. Figure 2 In example embodiments of the inertial MEMS sensor 202, the signal can be routed through the substrate (e.g., CMOS) layer 208 to an external shelf of the substrate layer 208. In some embodiments, processing such as filtering, scaling, A / D conversion, and more complex calculations (e.g., orientation as performed by an embedded ASIC) can be performed within the MEMS sensor 202 (e.g., within the CMOS substrate layer 208). The sensed and / or processed output can be provided to external connection points or bond pads 210 that can be located on a "shelf" of the substrate layer 208 that extends beyond the other layers of the MEMS sensor 202 in the x-y plane.

[0024] In embodiments of the present disclosure, an isolation layer 220 (e.g., WPR photoresist) can cover portions of the substrate layer 208 (e.g., the shelf of the substrate layer and portions extending vertically from the shelf), portions of the MEMS layer 206 (e.g., the externally facing portions of the MEMS layer 206), and portions of the cover layer 204 (e.g., the top and sides of the cover layer 204). In some embodiments, the isolation layer 220 can include multiple layers and / or different materials at different portions of the external surfaces of the sensor layers 204 / 206 / 208, or in some embodiments, there can be no isolation layer 220, or can include other layer types in addition to or instead of the isolation layer 220.

[0025] In exemplary embodiments of particular layers and configurations of the MEMS sensor 202, a continuous portion of material, also referred to as the redistribution layer 212, can generally extend in the x-direction along the x-y plane of the external surface of the shelf of the substrate layer 208 from the respective electrical connection point 210 and can pass through a 90° angle between the external x-y plane surface of the substrate layer 208 and the external y-z plane surface of the substrate layer 208. The continuous portion of material 212 can then generally extend in the z-direction in the y-z plane of the external surfaces of the substrate layer 208, the MEMS layer 206, and the cover layer 204. Once the continuous portion of material 212 encounters the top (along the z-axis) surface of the cover layer 204, the continuous portion of material 212 can pass through a 90° angle between the external y-z plane surface of the cover layer 204 and the top external x-y plane surface of the cover layer 204.

[0026] Once above the external x-y plane surface of the cover layer 204, the continuous portion of material 212 can extend along the x-y plane surface to the respective electrical connection point 216. In the embodiment depicted in FIG. 2, the continuous portion of material 212 is connected to the electrical connection point 216a. In this manner, a direct electrical connection can be made between the respective electrical connection point 210 on the external surface of the CMOS layer 208 and the associated electrical connection point 216 on the external surface of the cover layer 204. Figure 2 In the embodiment depicted in FIG. 2, a first continuous portion of material is connected to the electrical connection point 216a, while second and third continuous portions of material (not depicted) are connected to the electrical connection points 216a and 216b, respectively. In this manner, a direct electrical connection can be made between the respective electrical connection point 210 on the external surface of the CMOS layer 208 and the associated electrical connection point 216 on the external surface of the cover layer 204. The electrical connection points 216 can be coupled to other components 230 of the end use device. In the embodiment depicted in FIG. 2, the electrical connection points 216 are coupled to a microprocessor 232 and a memory 234 of the end use device. Figure 2In exemplary embodiments of the MEMS sensor 202, the solder balls 214 form a soldered connection between the other components 230 and the cap layer 204 of the MEMS sensor 202. The solder balls 214 form a direct electrical and physical connection between the MEMS sensor 202 and the other components 230, providing processed and / or unprocessed output from the MEMS sensor 202 for use by other systems of the end-use device. The electrical connections provided by the solder balls 214 also allow signals to be provided from the other components 230 to the MEMS sensor 202. Exemplary signals to be provided to the MEMS sensor 202 include power signals, ground signals, clock signals, control signals (e.g., register control signals), and data signals exchanged according to a protocol. These signals are in turn distributed to the appropriate components of the MEMS package, via the solder balls 214 to the corresponding external electrical connection points 216, via the contiguous portions of material 212 to the external electrical connection points 210, and via the substrate (e.g., CMOS) layer 208 to the internal components of the MEMS sensor 202. Some signals (e.g., ground and / or power signals) can be provided directly to the cap layer 204, as depicted by the cap electrical connections 218. In Figure 2 In exemplary embodiments of the MEMS sensor 202, the cap layer 204 is insulated from the other layers of the MEMS device 202 by an insulating layer 222 (e.g., an oxide insulating layer).

[0027] In comparison to conventional MEMS devices, Figure 2 Exemplary embodiments of the MEMS sensor 202 do not require additional packaging layers or bonding to external components for electrical or physical connection. Removing intermediate packaging layers reduces the overall size of the MEMS sensor's package, while reducing cost and removing manufacturing steps. Furthermore, because the contiguous portions of material are fabricated directly on the external non-conductive surfaces of the layers of the MEMS sensor, wire bond connections between any of the layers of the MEMS sensor are not required. Additionally, the contiguous portions of material are patterned and positioned such that they do not contact each other and are less likely to contact other external conductive components. Additional insulating layers can also be formed directly on the contiguous portions of material. As such, epoxy is not required to secure and protect the wire bonds. Removing such additional material reduces the overall size of the sensor, reduces cost, and eliminates manufacturing steps. Figure 2 The reduced size and weight of the MEMS sensor 202 allows the MEMS sensor to be placed in even smaller environments with higher precision. Additionally, the direct connection of the solder coupling to the cap layer securely attaches the MEMS sensor to the other components. In combination with the reduced height and profile of the MEMS sensor, the force exerted on the solder coupling is significantly reduced.

[0028] The outer surface of the layers of the MEMS sensor 202 may be non-conductive, and in some embodiments, an additional layer of non-conductive material (e.g., photoresist layer 220) may be deposited on the outer surface of the MEMS sensor 202, which has continuous portions of material fabricated thereon (e.g., photoresist 220 patterned on the xy-plane and adjacent yz-plane surfaces of the substrate layer 208, the yz-plane surface of the MEMS layer 206, and the yz-plane and adjacent xy-plane surfaces of the capping layer 204). Exemplary materials for the continuous portions of material include copper (Cu), gold (Au), nickel (Ni), cobalt (Co), or tin (Sn), and aluminum (Al).

[0029] Although in this article Figure 2 and Figures 3-4 This disclosure is described within the context of a specific MEMS device type and configuration, but it can be applied to a wide variety of applications. In addition to MEMS sensors, this disclosure can be applied to any suitable MEMS device. Furthermore, while the substrate layer is described herein as a layer providing electrical connections between external connection points and internal components of the MEMS sensor, such electrical connections and connection points can be provided on other layers and / or multiple layers of the MEMS sensor. In addition to the three-layer MEMS sensor described herein, additional layers (e.g., ASIC processing layers bonded to the substrate layer) may be provided. In some embodiments, more than two layers may include electrical connection points. For example, some continuous portions of material may provide direct electrical connections only between layers of the MEMS sensor, while some continuous portions of material may provide direct electrical connections to external components. Different configurations of layers may have no shelves or multiple shelves, and in some embodiments, transitions between planar surfaces may be at angles other than 90°.

[0030] Figure 3 Some embodiments according to this disclosure are depicted. Figure 2 Exemplary top and front views of an exemplary MEMS device. Figure 3 In an exemplary embodiment, the first electrical connection point 210 is configured in a single uniform row on the shelf of the substrate layer 208. In some embodiments, other configurations including multiple rows of electrical connections, uniform distribution of electrical connections, and other patterns may be used (e.g., to correspond to associated components within the MEMS sensor 202). A continuous portion 212 of material is connected to a corresponding one of the electrical connection points 210 and extends along the xy plane of the substrate layer 208 in a direction along the yz vertical plane surface of the substrate layer 208. Although in Figure 3In exemplary embodiments of the material's continuous portion 212 extends only in the x-direction along the x-y plane exterior surface of the substrate 208, but in other embodiments (e.g., based on respective locations of the electrical connection points 210) the material's continuous portion 212 can extend in both the x-direction and the y-direction within the x-y plane.

[0031] The material's continuous portion 212 passes through a 90° angle between the exterior x-y plane surface of the substrate layer 208 and the exterior y-z plane surface of the substrate layer 208. In exemplary embodiments of the material's continuous portion 212 passes through a 90° angle between the exterior x-y plane surface of the substrate layer 208 and the exterior y-z plane surface of the substrate layer 208. Figure 3 In exemplary embodiments of the material's continuous portion 212 then can extend in the z-direction on the y-z plane exterior surface of the substrate layer 208, the MEMS layer 206, and the cap layer 204 until reaching the top x-y exterior surface of the cap layer 204. In some embodiments (not depicted in FIG. 2B) the material's continuous portion 212 can extend in both the y-direction and the z-direction, while generally extending in the z-direction, for example, to require less travel along the x-y plane exterior surface of the cap layer 204 to connect to the electrical connection points 216. Figure 3 In exemplary embodiments of the material's continuous portion 212 then can extend in the z-direction on the y-z plane exterior surface of the substrate layer 208, the MEMS layer 206, and the cap layer 204 until reaching the top x-y exterior surface of the cap layer 204. In some embodiments (not depicted in FIG. 2B) the material's continuous portion 212 can extend in both the y-direction and the z-direction, while generally extending in the z-direction, for example, to require less travel along the x-y plane exterior surface of the cap layer 204 to connect to the electrical connection points 216.

[0032] The material's continuous portion 212 passes through a 90° angle between the exterior y-z plane surface of the cap layer 204 and the exterior x-y plane surface of the cap layer 204. In exemplary embodiments of the material's continuous portion 212 passes through a 90° angle between the exterior y-z plane surface of the cap layer 204 and the exterior x-y plane surface of the cap layer 204. Figure 3 In exemplary embodiments of the material's continuous portion 212 then can extend in the z-direction on the y-z plane exterior surface of the substrate layer 208, the MEMS layer 206, and the cap layer 204 until reaching the top x-y exterior surface of the cap layer 204. In some embodiments (not depicted in FIG. 2B) the material's continuous portion 212 can extend in both the y-direction and the z-direction, while generally extending in the z-direction, for example, to require less travel along the x-y plane exterior surface of the cap layer 204 to connect to the electrical connection points 216. Figure 3 In exemplary embodiments of the material's continuous portion 212 then can extend in the z-direction on the y-z plane exterior surface of the substrate layer 208, the MEMS layer 206, and the cap layer 204 until reaching the top x-y exterior surface of the cap layer 204. In some embodiments (not depicted in FIG. 2B) the material's continuous portion 212 can extend in both the y-direction and the z-direction, while generally extending in the z-direction, for example, to require less travel along the x-y plane exterior surface of the cap layer 204 to connect to the electrical connection points 216.

[0033] As Figure 3As depicted in FIG. 2, a continuous portion of material 212 can extend along the x-y planar surface of the cap layer 204 to a corresponding electrical connection point 216. In this way, a direct electrical connection can be made between a corresponding electrical connection point 210 on the outer surface of the CMOS layer 208 and an associated electrical connection point 216 on the outer surface of the cap layer 204. The path for the continuous portion of material 212 on the top x-y planar outer surface can be selected based on a number of bases, including based on the respective y-axis location of the continuous portion of material extending from the y-z planar outer surface of the cap layer 204 to the x-y planar surface of the cap layer 204, the location of the electrical connection point 216, and desired electrical and RF characteristics (such as avoiding undesirable RF emissions or serving as a shield to sources of electromagnetic interference).

[0034] Figure 4 An example perspective view of an exemplary MEMS device according to some embodiments of the disclosure is depicted in FIG. 2. Figures 2-3 An example perspective view of an exemplary MEMS device according to some embodiments of the disclosure is depicted in FIG. 2. Figure 5 The perspective view of FIG. 2 illustrates the MEMS sensor 202 as completed prior to connection to other components via solder balls 214. The layers of the MEMS sensor 202 are not visible as additional layers such as a photoresist layer have been applied to the outer surfaces of the MEMS sensor prior to the application of the continuous portion of material 212.

[0035] Figure 5 An example perspective view of an exemplary MEMS device according to some embodiments of the disclosure is depicted in FIG. 2. Figure 5 However, it should be understood that the methods and steps described in Figure 5 may be applied to a variety of MEMS designs with direct electrical connections, sensing element types, processing circuitry, and measurement techniques. While a specific order and flow of steps are depicted in Figure 5 it should be understood that in some embodiments, one or more of the steps can be modified, moved, removed, or added, and the Figure 5 flow depicted in FIG. 2 can be modified.

[0036] At step 502, a wafer of a MEMS device (e.g., a MEMS inertial sensor) can be obtained. In exemplary embodiments, the wafer can be pre-processed to manufacture and bond respective layers of the MEMS device (e.g., a cap layer, a MEMS layer, and a CMOS layer) and can include locations for placement of electrical connection points.

[0037] At step 504, an isolation layer (e.g., WPR photoresist) can be deposited by spray coating on exposed surfaces of the MEMS device of the wafer. In an example embodiment, the substrate (e.g., CMOS) layer of the MEMS device can be at a lower surface of the wafer, while the MEMS layer and the cap layer are at increasingly greater distances from the lower surface. The exposed surfaces can include any exposed portions of these layers, including, for example, horizontal shelves of the substrate layer, vertical surfaces of all three layers, and an upper horizontal surface of the cap layer.

[0038] At step 506, the isolation layer can be patterned to create trenches in the isolation layer. The trenches can expose one or more locations, such as electrical connection points of the substrate (e.g., CMOS layer) and the cap layer, and / or provide locations for conductive paths between the electrical connection points and other sensor portions, such as a ground plane of the cap layer. In an example embodiment, only a subset of the electrical connection points requiring direct access to the surface of the MEMS device (e.g., at the shelves of the substrate layer and / or a subset of the electrical connection points of the cap layer) can be patterned.

[0039] At step 508, a seed layer (e.g., Ti / Cu seed layer) can be applied (e.g., sputtered) on the isolation layer and exposed portions of the MEMS device (i.e., the trenches). At step 510, a plating photoresist mold can be applied, for example, by spray coating. The plating photoresist is subsequently patterned. In an example embodiment, the spray coating can cover the seed layer and the isolation layer, and the patterning of the plating photoresist can correspond to the locations of the electrical connection points and the conductive paths between them. As a result of the creation of the plating mold, some of the electrical connection points (e.g., for the shelves of the substrate layer and power to the cap layer) can be exposed through the isolation layer (applied at step 504), and some of the electrical connection points and conductive paths (e.g., the electrical connection points of the cap layer and the conductive paths connecting between other devices and the electrical connection points of the substrate layer) can be patterned on the isolation layer.

[0040] At step 512, the redistribution layer (e.g., conductive paths of a continuous portion 212 of material, such as a Cu / Ni layer), followed by the electrical connection points 210 and 216 (e.g., under bump metallization layers, such as Au), can be plated at the patterned locations of the plating mold to form and electrically connect the electrical connection points and the conductive paths between the electrical connection points (i.e., the continuous portion of material).

[0041] At step 514, the photoresist applied at step 510 can be stripped, and the unused portions of the seed layer (e.g., without the redistribution layer and under bump metallization layers applied on the seed layer) can be etched, thereby exposing the isolation layer, the redistribution layer, and the under bump metallization layers.

[0042] At step 516, an additional layer of isolation (e.g., photoresist) can be sprayed on the exposed layer and patterned, for example, to facilitate exposure of the connection points 210 and 216 (e.g., under bump metallization). At step 518, the connection points 210 and 216 (e.g., under bump metallization) can be etched. At step 520, any exposed portions of the conductive path (e.g., redistribution layer) can be electrically passivated (e.g., using plasma). At step 522, electrical connections such as solder bumps can then be formed over the exposed connection points (e.g., under bump metallization of the cap), providing physical and electrical connections to other components in the final use device. The wafer can then be diced to create individual MEMS devices for integration with other components in the final use device.

[0043] The foregoing description includes example embodiments in accordance with the present disclosure. These examples are provided for illustrative purposes only and are not intended to limit the disclosure. It will be understood that the present disclosure can be implemented in different forms without departing from the spirit of the disclosure, and that the skilled person can implement various modifications, optimizations and variations consistent with the following claims.

Claims

1. A microelectromechanical accelerometer, comprising: First layer; Second layer; A microelectromechanical layer, coupled between a first layer and a second layer, wherein the microelectromechanical layer includes one or more microelectromechanical components; The first plurality of electrical connection points are located on the outer surface of the first layer; A second plurality of electrical connection points are located on the outer surface of the second layer, wherein at least one of the second plurality of electrical connection points is directly electrically connected to the second layer via a cover electrical connection; and Multiple conductive paths, wherein each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of electrical connection points, and wherein each conductive path is deployed over the outer surface of the first layer, the outer surface of the second layer and the outer surface of the microelectromechanical layer via an isolation layer.

2. The microelectromechanical accelerometer as claimed in claim 1, wherein the second plurality of electrical connection points comprises a plurality of solder coupling elements.

3. The microelectromechanical accelerometer as claimed in claim 2, wherein the second outer surface is perpendicular to the third outer surface.

4. The microelectromechanical accelerometer of claim 2 further includes one or more external components coupled to the plurality of solder couplers.

5. The microelectromechanical accelerometer of claim 4, wherein the plurality of solder couplers electrically connect the first plurality of electrical connection points to the one or more external components.

6. The microelectromechanical accelerometer of claim 5, wherein the first plurality of electrical connection points are not electrically connected to any external component other than the one or more external components electrically connected via the plurality of solder couplers.

7. A microelectromechanical accelerometer, comprising: First layer; Second layer; A microelectromechanical layer, coupled between a first layer and a second layer, wherein the microelectromechanical layer includes one or more microelectromechanical components; The first plurality of electrical connection points are located on the outer surface of the first layer; The second plurality of electrical connection points are located on the outer surface of the second layer; and Multiple conductive paths, wherein each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of electrical connection points, wherein each conductive path is deployed over the outer surface of a first layer, the outer surface of a second layer and the outer surface of a microelectromechanical layer via an insulating layer, wherein the first layer includes a circuit system, wherein the outer surface of the first layer includes a shelf extending beyond the second layer and the microelectromechanical layer, and wherein the first plurality of electrical connection points are located at the shelf.

8. The microelectromechanical accelerometer of claim 7, wherein the first plurality of electrical connection points are bonding pads.

9. The microelectromechanical accelerometer of claim 8, wherein a plurality of signals are received at the bonding pads via a first layer.

10. The microelectromechanical accelerometer of claim 9, wherein the surface of the shelf made of conductive material is parallel to the outer surface of the second layer.

11. The microelectromechanical accelerometer of claim 10, wherein the surface of the conductive material shelf and the outer surface of the second layer are perpendicular to the third outer surface.

12. The microelectromechanical accelerometer of claim 9, wherein the second plurality of electrical connection points comprises a plurality of solder coupling elements.

13. The microelectromechanical accelerometer of claim 12, further comprising one or more external components coupled to the plurality of solder couplers.

14. The microelectromechanical accelerometer of claim 13, wherein the plurality of solder couplers electrically connect the first plurality of electrical connection points to the one or more external components.

15. A microelectromechanical accelerometer, comprising: First layer; Second layer; A microelectromechanical layer, coupled between a first layer and a second layer, wherein the microelectromechanical layer includes one or more microelectromechanical components; The first plurality of electrical connection points are located on the outer surface of the first layer; The second plurality of electrical connection points are located on the outer surface of the second layer; and Multiple conductive paths, wherein each conductive path provides a continuous portion of material between one of the first plurality of electrical connection points and one of the second plurality of electrical connection points, wherein each conductive path is deployed over the outer surface of a first layer, the outer surface of a second layer and the outer surface of a microelectromechanical layer via an isolation layer, and wherein the second layer and the microelectromechanical layer are electrically isolated from each other.

16. The microelectromechanical accelerometer of claim 15, wherein the oxide insulating layer isolates the second layer from the microelectromechanical layer.

17. The microelectromechanical accelerometer of claim 15, wherein the first layer and the microelectromechanical layer are electrically connected.

18. The microelectromechanical accelerometer of claim 17, wherein the second plurality of electrical connection points comprises a plurality of solder couplings.

19. The microelectromechanical accelerometer of claim 18, further comprising one or more external components coupled to the plurality of solder couplers.

20. The microelectromechanical accelerometer of claim 19, wherein the plurality of solder couplers electrically connect the first plurality of electrical connection points to the one or more external components.

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