Micro-mechanical arm array and micro-electro-mechanical system actuator

Abstract

A micromanipulator array and a microelectromechanical system (MEMS) actuator are disclosed. The MEMS structure can be used as an actuator for a motion image sensor to achieve optical image stabilization. The MEMS actuator includes one or more micromanipulator arrays. Each array includes a first array of spaced fingers formed of a piezoelectric material and a second array of spaced fingers formed of a conductive material. The distal ends of the first and second finger arrays are interposed between each other. Microsprings connect the interposed distal ends of each pair of adjacent fingers together. Metal caps are located above the distal ends of the first and second finger arrays. The microsprings connect the metal caps to the distal ends of each finger in the first finger array. This structure increases stability and strength.

Description

Technical Field

[0001] This disclosure pertains to micromanipulator arrays and microelectromechanical system actuators. Background Technology

[0002] Micro-electromechanical systems (MEMS) are a technology that uses miniature mechanical and electromechanical components (e.g., devices or structures) on a wafer substrate. Devices or structures that can be used in MEMS include sensors, actuators, and other structures. MEMS devices can be used in a wide range of applications, including but not limited to optical / imaging devices.

[0003] Microelectromechanical systems (MEMS) structures can be fabricated using a photolithography process, which uses ultraviolet light to transfer the desired mask pattern onto a photoresist layer on a semiconductor wafer. The pattern can then be transferred to a layer beneath the photoresist using an etching process. This process can be repeated multiple times with different patterns to build different layers on the wafer substrate and fabricate useful devices. Utility Model Content

[0004] This disclosure reveals a novel micromanipulator array with improved stability and strength.

[0005] This disclosure provides a micromanipulator array. The micromanipulator array includes a wafer, a piezoelectric finger array, a conductive finger array, a plurality of microsprings, a metal cap, and a cavity. The piezoelectric finger array is on the wafer. The conductive finger array is on the wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form the distal ends of a plurality of adjacent fingers interposed with each other. A plurality of microsprings are located between the distal ends of the adjacent fingers interposed with each other and on each finger in the piezoelectric finger array. The metal cap contacts each finger in the conductive finger array and each of the microsprings on the piezoelectric finger array. The cavity is located in the wafer below the piezoelectric finger array and the conductive finger array.

[0006] This disclosure also provides a micromanipulator array. The micromanipulator array includes a package, a piezoelectric finger array, a conductive finger array, a plurality of horizontal microsprings, a plurality of vertical microsprings, a metal cap, and a cavity. The package includes a top wafer bonded to a bottom wafer. The piezoelectric finger array is located in the top wafer. The conductive finger array is located in the top wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form a plurality of distal ends of adjacent fingers interposed with each other, and each finger in the piezoelectric finger array and each finger in the conductive finger array is covered by a dielectric layer. A plurality of horizontal microsprings are located between the distal ends of adjacent interposed fingers, each of the horizontal microsprings including a dielectric layer bonded to a metal layer. A plurality of vertical microsprings are located on the plurality of fingers of the piezoelectric finger array, each of the vertical microsprings including a dielectric layer bonded to a metal layer. The metal cap contacts each finger in the array of conductive fingers and each of the vertical microsprings in the array of piezoelectric fingers. The cavity is located within the top wafer.

[0007] This disclosure also provides a microelectromechanical system (MEMS) actuator. The MEMS actuator includes an anchor structure and an array of multiple micro-manipulators. The micro-manipulator arrays are connected to the anchor structure, each of the micro-manipulator arrays including an array of piezoelectric spacer fingers and an array of conductive spacer fingers. The piezoelectric spacer finger array extends from a first arm along a first horizontal direction. The conductive spacer finger array extends from a second arm along the first horizontal direction, wherein multiple distal ends of the piezoelectric spacer finger array and multiple distal ends of the conductive spacer finger array are interposed between each other to form the distal ends of multiple adjacent fingers interposed to each other. Attached Figure Description

[0008] When with attachment Figure 1 The best way to understand the various aspects of this disclosure is by reading the following detailed description. It should be noted that, in accordance with industry standard practice, the various features may not be drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily increased or decreased.

[0009] Figure 1 This is a side cross-sectional view of a micromechanical arm array according to some embodiments of the present disclosure;

[0010] Figure 2 This is an enlarged side cross-sectional view of a micromanipulator array according to some embodiments of the present disclosure;

[0011] Figure 3AThis is a plan view of the micro-manipulator array in the first embodiment. The micro-manipulator array has a first piezoelectric finger array, a second conductive finger array, and a micro-spring. The distal ends of the first piezoelectric finger array and the distal ends of the second conductive finger array are inserted between each other, and the micro-spring connects adjacent fingers. The ratio of the number of piezoelectric fingers to the number of conductive fingers is 2:1.

[0012] Figure 3B This is a plan view of the micro-robotic arm array in the second embodiment. The micro-robotic arm array has a first piezoelectric finger array into which a second conductive finger array is inserted; the ratio of the number of piezoelectric fingers to the number of conductive fingers is 1:1.

[0013] Figure 3C This is a plan view of the micro-robotic arm array in the third embodiment. The micro-robotic arm array has a first piezoelectric finger array into which the second conductive finger array is inserted; the ratio of the number of piezoelectric fingers to the number of conductive fingers is 3:1.

[0014] Figures 4A to 4C This is a flowchart of a first method for manufacturing a micro-manipulator array for a microelectromechanical system actuator, according to some embodiments;

[0015] Figure 5 This is a side cross-sectional view of the package used to manufacture micro-robotic arm arrays;

[0016] Figure 6A This is a plan view of the package after the first etching step has been performed; Figure 6B yes Figure 6A The package is shown in the side cross-sectional view along line BB; Figure 6C yes Figure 6A A cross-sectional view of the package along line CC on the side; Figure 6D yes Figure 6A A cross-sectional view of the package along line DD on the side;

[0017] Figure 7 This is a side cross-sectional view of the package after the first dielectric layer has been formed;

[0018] Figure 8 This is a side cross-sectional view of the package after metal deposition;

[0019] Figure 9A This is a side cross-sectional view of the package after etching is performed to form a metal layer on the pillar; Figure 9B It is a floor plan;

[0020] Figure 10 This is a side cross-sectional view of the package after silicon deposition;

[0021] Figure 11AThis is a side cross-sectional view of the package after etching to form sacrificial spacers on the pillars; Figure 11B It is a floor plan;

[0022] Figure 12 This is a side cross-sectional view of the package after the first dielectric layer is added to the newly exposed surface;

[0023] Figure 13A This is a side cross-sectional view of the package after the piezoelectric material for forming the first piezoelectric finger array has been deposited. Figure 13B It is a floor plan;

[0024] Figure 14 This is a side cross-sectional view of the package after the conductive material for forming the second conductive finger array is deposited on the top wafer.

[0025] Figure 15A This is a side cross-sectional view of the package after chemical mechanical planarization (CMP) is performed on the conductive material; Figure 15B It is a floor plan;

[0026] Figure 16 This is a side cross-sectional view of the package after etching to remove conductive material from the trench;

[0027] Figure 17 This is a side cross-sectional view of the package after a first dielectric layer is further added to the two finger arrays;

[0028] Figure 18 This is a side cross-sectional view of the package after partial etching of the first dielectric layer to expose a portion of the top wafer;

[0029] Figure 19 This is a side cross-sectional view of the package after the first etch stop layer has been deposited on the top wafer;

[0030] Figure 20 This is a side cross-sectional view of the package after the second dielectric layer has been formed;

[0031] Figure 21A This is a side cross-sectional view of the package after the second dielectric layer has been partially etched. Figure 21B It is a floor plan;

[0032] Figure 22 This is a side cross-sectional view of the package after the second etch stop layer has been deposited on the top wafer;

[0033] Figure 23A This is a side cross-sectional view of the package after the etch stop layer has been etched to expose multiple parts of the top wafer; Figure 23B It is a floor plan;

[0034] Figure 24 This is a side cross-sectional view of the package after the third dielectric layer has been deposited;

[0035] Figure 25A This is a side cross-sectional view of the package after the third dielectric layer has been etched to form a vertical dielectric layer on the first piezoelectric finger array. Figure 25B It is a floor plan;

[0036] Figure 26 This is a side cross-sectional view of the package after metal deposition;

[0037] Figure 27A This is a side cross-sectional view of the package after the etching process to form the metal cap has been performed; Figure 27B It is a floor plan;

[0038] Figure 28A This is a side cross-sectional view of the package after the passivation layer has been formed; Figure 28B It is a floor plan;

[0039] Figure 29A This is a side cross-sectional view of the package after silicon etching is performed on the top wafer to form the cavity under the micro-robotic arm array; Figure 29B It is a floor plan;

[0040] Figure 30A This is a side cross-sectional view of the package after annealing has been performed and the bottom wafer has been removed, leaving the top wafer. Figure 30B It is a floor plan;

[0041] Figure 31A This is a flowchart of a second method for manufacturing a micromanipulator array for a microelectromechanical system actuator, according to some embodiments;

[0042] Figure 31B This is a flowchart of a third method for manufacturing a micromanipulator array for a microelectromechanical system actuator, according to some embodiments;

[0043] Figure 32 This is a plan view of a microelectromechanical system actuator according to some implementation methods;

[0044] Figure 33 This is a flowchart of a method for stabilizing an optical image against external motion, according to some embodiments;

[0045] Figure 34A This is a side cross-sectional view of the optical image capturing device located in the first position; Figure 34B This is a side cross-sectional view of the device when it is in the second position.

[0046] [Symbol Explanation]

[0047] 100: Package

[0048] 102: Central Section

[0049] 110: Top wafer

[0050] 112: Cavity

[0051] 114: Top surface

[0052] 115: Thickness

[0053] 120: Bottom wafer

[0054] 122: Cavity

[0055] 125: Thickness

[0056] 130: Bonding layer

[0057] 132: Anchor arm section

[0058] 134: Drive comb section

[0059] 135: Trench

[0060] 136: Hub Section

[0061] 137: Trench

[0062] 138: Inner Frame Section

[0063] 139: Trench

[0064] 140: Spring section

[0065] 142: Outer frame section

[0066] 143: Trench

[0067] 148: Micro-robotic arm array

[0068] 150: First finger array

[0069] 152: Nuclear

[0070] 154: Overlay

[0071] 156: Free End

[0072] 158: Fixed end

[0073] 160: Remote

[0074] 162: Proximal

[0075] 163: Height

[0076] 165: Width

[0077] 167: Length

[0078] 168: First Arm

[0079] 170: Second finger array

[0080] 172: Nuclear

[0081] 174: Overlay

[0082] 176: Free End

[0083] 178: Fixed end

[0084] 180: Remote

[0085] 182: Proximal

[0086] 183: Altitude

[0087] 185: Width

[0088] 187: Length

[0089] 188: Second Arm

[0090] 190: Metal Cap

[0091] 192: Top surface

[0092] 200: Passivation layer

[0093] 202: Microspring

[0094] 204: Microspring

[0095] 206: Metal layer

[0096] 208: Dielectric layer

[0097] 209: Length

[0098] 210: Micro-spring front-drive structure

[0099] 212: Micro-spring front-drive structure

[0100] 214: First Direction

[0101] 216: Second Direction

[0102] 220: Groove

[0103] 222: Pillar

[0104] 224: Bracket

[0105] 230: Trench

[0106] 232: Trench

[0107] 240: First dielectric layer

[0108] 242: Metal

[0109] 244: Sacrificial Material

[0110] 246: Sacrificial Interstitial

[0111] 252: Piezoelectric materials

[0112] 254: Conductive material layer

[0113] 256: First etch stop layer

[0114] 258: Second dielectric layer

[0115] 260: Second etch stop layer

[0116] 262: Spacer

[0117] 264: Slot

[0118] 270: Third dielectric layer

[0119] 272: Metal layer

[0120] 300: First Method

[0121] 302: Steps

[0122] 304: Steps

[0123] 306: Steps

[0124] 308: Steps

[0125] 310: Steps

[0126] 312: Steps

[0127] 314: Steps

[0128] 316: Steps

[0129] 318: Steps

[0130] 320: Steps

[0131] 322: Steps

[0132] 324: Steps

[0133] 326: Steps

[0134] 328: Steps

[0135] 330: Steps

[0136] 332: Steps

[0137] 334: Steps

[0138] 336: Steps

[0139] 338: Steps

[0140] 340: Steps

[0141] 342: Steps

[0142] 344: Steps

[0143] 346: Steps

[0144] 348: Steps

[0145] 350: Steps

[0146] 352: Steps

[0147] 354: Steps

[0148] 356: Steps

[0149] 360: Method

[0150] 362: Steps

[0151] 364: Steps

[0152] 366: Steps

[0153] 368: Steps

[0154] 370: Steps

[0155] 372: Steps

[0156] 380: Method

[0157] 382: Steps

[0158] 384: Steps

[0159] 386: Steps

[0160] 388: Steps

[0161] 390: Steps

[0162] 392: Steps

[0163] 400: Microelectromechanical system actuator

[0164] 402: Frame

[0165] 404: Sensor connection element

[0166] 406: Anchor

[0167] 407: Anchor arm

[0168] 408: Anchor Structure

[0169] 410: Support

[0170] 412: Hub

[0171] 414: Sensor bracket

[0172] 416: Box

[0173] 418: Optical image capturing device

[0174] 420: Casing

[0175] 422: Image sensor

[0176] 424: Lens

[0177] 440: Method

[0178] 442: Steps

[0179] BB: Line

[0180] CC: Line

[0181] DD: Line

[0182] X: Axis

[0183] Y: Axis

[0184] Z: axis Detailed Implementation

[0185] The following disclosure provides many different implementations or examples for achieving different features of the provided object. Specific examples of elements and compositions are described below to simplify this disclosure. Of course, these are merely examples and are not intended to limit this disclosure. For example, in the following description, forming a first feature on or over a second feature can include implementations where the first and second features are formed in direct contact, or implementations where additional features can be formed between the first and second features, thus the first and second features are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples of this disclosure. Such repetition is for simplicity and clarity and does not in itself specify a relationship between the various implementations and / or configurations discussed.

[0186] Furthermore, for ease of description, this document uses spatial relative terms such as “below,” “under,” “lower,” “above,” “over,” etc., to describe the relationship between one element or feature and another shown in the figures. In addition to the orientations described in the figures, spatial relative terms are also intended to include different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other directions), and the spatial relative terms used herein will be interpreted accordingly.

[0187] The numerical values ​​in this application specification and claims should be understood to include values ​​that remain the same when the significant figures are reduced to the same number, as well as values ​​that differ from the stated values ​​by less than the experimental error of the conventional measurements performed to determine the values ​​as described in this application. All scopes of this disclosure include the referenced endpoints.

[0188] The term "approximately" can include any numerical value that can vary without altering its fundamental function. When used with a range, "approximately" also reveals a range defined by the absolute values ​​of its two endpoints; for example, "approximately 2 to approximately 4" reveals a range "from 2 to 4". The term "approximately" can be plus or minus 10% of a specified numerical value.

[0189] This disclosure relates to structures composed of different layers. When the terms “on” or “above” are used to refer to two different layers (including a substrate), they may simply mean that one layer is on or above another. These terms do not require that the two layers be in direct contact with each other and allow other layers to be located between the two layers. For example, all layers in a structure may be considered to be located “on” the substrate, even if they are not in direct contact with the substrate. The term “direct” can be used to indicate that two layers are in direct contact with each other and there are no other layers between them. Furthermore, when referring to performing process steps on or on a substrate, this should be understood as performing such steps on any layers that may be present on the substrate, depending on the context.

[0190] This disclosure specifically relates to micromanipulator arrays for use as microelectromechanical system (MEMS) actuators. MEMS actuators convert electrical signals into mechanical signals and are typically electrically connected to other integrated circuits (ICs) to form a system. Such actuators are commonly used in optical image-capturing devices, such as cameras that can be used as part of a standalone handheld camera or mobile phone. However, micromanipulator arrays can be damaged, for example, due to impacts or shocks, such as when falling from a height.

[0191] This disclosure discloses a novel micromanipulator array with improved stability and strength. The micromanipulator array includes two finger arrays, each extending from one arm. In some embodiments, one array is made of a piezoelectric material. The other array is made of a non-piezoelectric conductive material, such as polycrystalline silicon. Microsprings are present between adjacent fingers and also between the metal cap and the piezoelectric finger array. In other embodiments, the ratio of the number of fingers in the first finger array to the number of fingers in the second finger array is an integer greater than 1. Furthermore, the spring life is improved.

[0192] Figure 1 This is a side cross-sectional view of a first exemplary embodiment of a package 100 including a micro-mechanical system-integrated micromanipulator array 148 according to some embodiments of the present disclosure.

[0193] Package 100 includes a top wafer 110 (also known as a device wafer) and a bottom wafer 120 (also known as a handle wafer), which are bonded together by a bonding layer 130. This package is also known as a silicon-on-insulator (SOI) substrate.

[0194] Next, a micro-robotic arm array 148 exists in the top wafer 110. The top wafer 110 has multiple portions in the horizontal direction, labeled as anchor arm portion 132, drive comb portion 134, hinge portion 136, inner frame portion 138, spring portion 140, and outer frame portion 142. The micro-robotic arm array 148 is located in the drive comb portion 134. These different portions together constitute the quadrant of the microelectromechanical system actuator (discussed later in this document).

[0195] The anchor arm portion 132 provides structural integrity and helps support the drive comb portion. The pivot portion 136 allows the pivot to operate, or allows controlled rotation relative to other elements of the drive comb portion. The inner frame portion 138 provides structural support and stability. The spring portion 140 provides elasticity to maintain the required positioning and movement of the elements, and also provides a restoring force for the elements to return to their original position after being actuated. The outer frame portion 142 generally provides structural integrity to protect the internal elements from external and environmental forces.

[0196] Cavity 112 exists within top wafer 110. Microrobotic arm array 148 is disposed within the cavity and can move freely within it. The cavity also extends continuously below the hub portion 136, inner frame portion 138, and spring portion 140. Two smaller cavities 122 also exist within bottom wafer 120, and they are generally located below the hub portion 136, inner frame portion 138, and spring portion 140. Cavity 112 in top wafer 110 connects to the two smaller cavities 122 in bottom wafer 120.

[0197] The micromanipulator array comprises two separate arrays of multiple fingers: a first finger array 150 (or first piezoelectric finger array) and a second finger array 170 (or second conductive finger array). The piezoelectric fingers are spaced apart from each other. Similarly, the conductive fingers are also spaced apart from each other. As shown in the figure, two piezoelectric fingers of the first finger array 150 are inserted between two conductive fingers of the second finger array 170.

[0198] A metal cap 190 is present above the first finger array 150 and the second finger array 170. The first finger array 150 is connected to the metal cap 190 by a vertical microspring 202. In addition, a horizontal microspring 204 is present between adjacent fingers in the first finger array 150 and the second finger array 170.

[0199] Figure 2 This is an enlarged side cross-sectional view of the micro-robotic arm array 148. It should be noted that this is a simplified schematic diagram for illustrative purposes only and is not intended to fully represent the complete micro-robotic arm array 148.

[0200] As shown in the figure, each piezoelectric finger of the first finger array 150 includes a core 152 formed of a piezoelectric material. A capping layer 154 is present around all sides of the core 152 and isolates the core from the cavity. The capping layer may act as an etch stop layer and is typically made of a dielectric material. Each piezoelectric finger also has a free end 156 (or bottom end) and a fixed end 158 (or top end). In this view, the piezoelectric finger has a height 163 and a width 165.

[0201] Similarly, each conductive finger in the second finger array 170 includes a core 172 formed of a non-piezoelectric conductive material. A capping layer 174 is present around all sides of the core 172 and isolates the core from the cavity. The capping layer may act as an etch stop layer and is typically made of a dielectric material. Each conductive finger also has a free end 176 (or bottom end) and a fixed end 178 (or top end). The conductive fingers have a height 183 and a width 185. In some specific embodiments, the conductive fingers in the second finger array 170 are made of polysilicon, while the capping layer is formed of silicon dioxide (SiO2).

[0202] As shown in the figure, the height 183 of the conductive fingers is greater than the height 163 of the piezoelectric fingers. In some specific embodiments, the heights 183 and 163 can independently be from about 150 micrometers (μm) to about 200 μm. Other ranges are also within the scope of this disclosure. Similarly, the width 185 of the conductive fingers is greater than the width 165 of the piezoelectric fingers. However, such dimensions may not be necessary for the operation of the micro-robotic arm array, and the trend in dimensions may be reversed. Furthermore, the fingers in the first finger array 150 and the second finger array 170 are illustrated with their top surfaces at the same height or horizontal plane. Again, this may not be necessary for the operation of the micro-robotic arm array.

[0203] A passivation layer 200 is present on the top surface 192 of the metal cap. As shown, the metal cap 190 directly contacts the fixed end 178 of the second finger array 170, but not the fixed end 158 of the first finger array 150. Instead, the fixed end of the first finger array 150 is connected to the metal cap 190 via a "vertical" microspring 202. The opposite arrangement is also contemplated, with the metal cap 190 directly contacting the first finger array 150, while the second finger array 170 is connected to the metal cap 190 via a "vertical" microspring 202. A "horizontal" microspring 204 is present between adjacent fingers in the first finger array 150 and the second finger array 170. The free ends 156 and 176 in both finger arrays are able to move freely under the metal cap.

[0204] Each microspring is made of a combination of two layers: a metal layer 206 and a dielectric layer 208. In some specific embodiments, the metal layer 206 is a metal or metal alloy, such as, but not limited to, aluminum (Al) or aluminum alloys (e.g., AlCu); copper (Cu); tungsten (W); or nickel (Ni). In some specific embodiments, the dielectric layer is made of silicon dioxide (SiO2), although other materials may also be used. Generally, the two layers have different or opposite tensile properties, thus providing vibration isolation, resonance control, damping, and energy dissipation. This also reduces the energy transferred to the fingers due to external impacts. In some embodiments, the length 209 of the microsprings 202 and 204 may be about 1.6 micrometers (μm) or longer, although other ranges are also within the scope of this disclosure. This corresponds to the distance between adjacent fingers. In some embodiments, the distance between two adjacent piezoelectric fingers is different from the distance between a piezoelectric finger in the first finger array 150 and its adjacent conductive finger in the second finger array 170.

[0205] Figure 3A yes Figure 2 A plan view of the micro-robotic arm array. Again, this is a simplified schematic diagram for illustrative purposes only and is not intended to fully represent the complete micro-robotic arm array 148.

[0206] As shown, piezoelectric fingers extend from distal end 160 along a first direction 214 to proximal end 162 connected to first arm 168. In other words, piezoelectric fingers in first finger array 150 extend from first arm. First arm is also made of piezoelectric material and covered by a capping layer (not shown here). Conductive fingers extend from distal end 180 along a second direction 216 opposite to the first direction to proximal end 182 connected to second arm 188. In other words, conductive fingers in second finger array 170 extend from second arm. Second arm is also made of conductive material and covered by a capping layer (not shown here). Fingers in first finger array 150 and second finger array 170 extend along a first horizontal direction (i.e., axis X). Both arms, namely first arm 168 and second arm 188, extend along a second horizontal direction (i.e., axis Y, where axis X is perpendicular to axis Y, and axis Z is perpendicular to both axis X and axis Y). Although not illustrated here, the other ends of the two arms are connected to the anchor arm portion 132 and the outer frame portion 142.

[0207] The piezoelectric fingers in the first finger array 150 can be described as extending from the first arm 168 toward the conductive fingers in the second finger array 170, and vice versa. The distal ends 160 and 180 of the fingers in the first and second finger arrays 150 and 170 are inserted into or interleaved with each other. In other words, the distal ends of the first finger array overlap with the distal ends of the second finger array. In some embodiments, the lengths 167 and 187 of the fingers in the first and second finger arrays 150 and 170 can be from about 1 millimeter (mm) to about 3 mm, although other values ​​and ranges are also within the scope of this disclosure.

[0208] Horizontal microsprings 204 connect the distal ends of adjacent fingers together. Metal caps 190 cover the distal ends and are shown as dashed lines in the figures. It should be noted that the first finger array 150 and the second finger array 170 of the micromanipulator array can contain a large number of piezoelectric fingers and a large number of conductive fingers, not limited by these schematic figures, such as those shown as consecutive dots in the figures. In the figures, the ratio of piezoelectric fingers in the first finger array 150 to conductive fingers in the second finger array 170 is 2:1, i.e., the ratio is an integer of 2. The piezoelectric fingers are distributed such that there are two piezoelectric fingers grouped together between groups of two conductive fingers.

[0209] Figure 3B This is a plan view of a second embodiment of the micro-robotic arm array 148. In this embodiment, the ratio of piezoelectric fingers in the first finger array 150 to conductive fingers in the second finger array 170 is 1:1. There is one piezoelectric finger between two conductive fingers grouped together.

[0210] Figure 3C This is a plan view of a third embodiment of the micro-robotic arm array 148. In this embodiment, the ratio of piezoelectric fingers in the first finger array 150 to conductive fingers in the second finger array 170 is 3:1, i.e., the ratio is an integer of 3. There are three piezoelectric fingers between groups of two conductive fingers. Therefore, typically, the ratio of piezoelectric fingers in the first finger array 150 to conductive fingers in the second finger array 170 can range from about 1:1 or greater. The maximum ratio can be about 10:1. It should be noted that an "array" of fingers can include as few as one finger. Typically, each finger array can include from one finger to about 60 fingers, or about 100 fingers, or up to 1000 fingers, depending on the requirements.

[0211] Figures 4A to 4CA flowchart of a first method 300 for fabricating a micromanipulator array for use as a microelectromechanical system actuator is shown according to several embodiments. Some steps of this method are also illustrated in... Figures 5 to 30B The accompanying figures provide different views to better understand the contents of this disclosure. While the method steps discussed below involve forming a single array of micromanipulators with a small number of fingers, this discussion should also be interpreted broadly as applicable to forming arrays of multiple micromanipulators in parallel on a single drive comb portion, as well as forming numerous fingers. The figures do not show the formation of the entire actuator, only the drive comb portion.

[0212] First of all, Figure 4A In step 302, such as Figure 5 As shown, the top wafer 110 is connected to the bottom wafer 120 to form package 100. Alternatively, as... Figure 4A As shown in step 304, the package is received.

[0213] The top wafer 110 and the bottom wafer 120 can be independently wafers made of, for example, semiconductor materials. Such semiconductor materials may include silicon, for example, in the form of crystalline silicon. In some alternative embodiments, the substrate may be made of other elemental semiconductors, such as germanium, or may include compound semiconductors such as silicon carbide (SiC), gallium arsenide (GaAs), gallium carbide, gallium phosphide, indium arsenide (InAs), indium phosphide (InP), silicon germanium, silicon germanium carbide, gallium arsenide phosphide, or gallium indium phosphide. In some specific embodiments, both wafers are made of silicon.

[0214] The top wafer includes a top surface 114, which also serves as the top surface of the package. Typically, the top wafer 110 has a relatively small thickness 115 (e.g., in the range of approximately 200 μm), making it very flexible and therefore difficult to process. The bottom wafer 120 has a relatively large thickness 125 (e.g., in the range of approximately 500 μm) to increase the overall thickness of the package, thereby providing mechanical stability during processing and aiding in electrical isolation (if required). Two cavities 122 are already present in the bottom wafer 120. The bonding layer 130 can be formed by fusion bonding, for example, by a heating and / or pressing process without the use of any additional layers. As another example, both wafers can have dielectric layers on suitable surfaces, which are then heated and the two wafers pressed together to form the bonding layer.

[0215] Next, in Figure 4A In step 306, such as Figures 6A to 6DAs shown, the top wafer 110 is patterned to form a recess 220. Multiple pillars 222 are formed within the recess. These pillars are spaced apart from each other. The pillars can be formed on a support 224 according to the required height of the fingers of the micromanipulator array. The recess is part of the drive comb portion 134. Additional trenches 135 are also formed in the drive comb portion. Additional trenches 137, 139, and 143 are also formed in the top wafer, and their positions will correspond to the pivot portion, inner frame portion, spring portion, and outer frame portion. The pillars correspond to the positions where horizontal microsprings will be formed.

[0216] Figure 6A This is a plan view of the package after the patterning / etching steps. As shown, a recess is molded within the recess to form two different sets of trenches 230 and 232, corresponding to two different arrays of fingers. It is worth noting that a "set" of trenches may consist of as few as one trench. The different depths of the recess 220, the support (see trench 230), and the pillars 222 are illustrated with different dot patterns. Figure 6B yes Figure 6A The package is shown in a side cross-sectional view along line BB. This cross-section passes through the distal end of the finger and the location where the microspring will be formed. Figure 6C yes Figure 6A The package is shown in a side cross-sectional view along line CC. In this cross-section, only the grooves 230 of the first finger array are visible in the recess 220. Figure 6D yes Figure 6A The package is shown in a side cross-sectional view along line DD. In this cross-section, only the grooves 232 of the second finger array are visible in the recess 220. It should be noted that... Figures 7 to 30B The cross-sectional view is along Figure 6A BB line.

[0217] Next, in Figure 4A In step 308, such as Figure 7 As shown, a first dielectric layer 240 is formed on the exposed surface of the recess 220. The first dielectric layer is also formed on other exposed surfaces of the top wafer 110, including on the top surface 114. In some specific embodiments, the first dielectric layer is made of silicon dioxide (SiO2) and can be formed using a thermally oxidized silicon wafer. Of particular note is that portions of the first dielectric layer 240 on the pillar 222 will form horizontally oriented dielectric layers 208 for microsprings.

[0218] Next, in Figure 4A In step 310, such as Figure 8 As shown, metal 242 is deposited on the top wafer. Next, in... Figure 4A In step 312, such as Figure 9A and Figure 9BAs shown, the metal is patterned to form a metal layer 206 on each pillar 222. This metal layer will form a second layer of horizontal microsprings. In some specific embodiments, the metal is aluminum (Al) or an aluminum alloy, such as AlCu. The metal can be deposited by vapor deposition or sputtering, plating, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable methods. Figure 9B As shown, the metal layer 206 exists only on the pillars 222, and not in the trenches 230 and 232 within the recesses. The combination of the dielectric layer 208 and the metal layer 206 on each pillar is also referred to herein as the microspring precursor structure 210 or the horizontal composite structure.

[0219] Next, in Figure 4A In step 314, such as Figure 10 As shown, sacrificial material 244 is deposited on the top wafer, including within the groove 220. The sacrificial material can be deposited using CVD, PVD, or other suitable methods. Next, in... Figure 4A In step 316, such as Figure 11A and Figure 11B As shown, the sacrificial material is patterned to form sacrificial spacers 246 on each pillar. Figure 11B As shown, the sacrificial spacer 246 is formed only on the pillar 222, and not in other areas of the recess. In some specific embodiments, the sacrificial material is the same material as the top wafer, such as silicon.

[0220] exist Figure 4A In step 318, such as Figure 12 As shown, a dielectric layer is formed on the exposed surfaces of the metal layer 206 and the sacrificial spacer 246. This step can be considered as increasing the first dielectric layer 240. In some specific embodiments, this is accomplished by performing thermal oxidation on the exposed surfaces. Therefore, the first set of trenches 230 and the second set of trenches 232 are completely separated from each other within the grooves.

[0221] Next, in Figure 4A In step 320, such as Figure 13A and Figure 13B As shown, piezoelectric material 252 is deposited into the trenches of the first group to form the first finger array 150. (Reference) Figures 3A to 3CThe first arm 168 is also formed in this step. Deposition can be performed using CVD, PVD, or other suitable methods. Examples of suitable piezoelectric materials may include barium titanate (BaTiO3, BTO), lead titanate (PbTiO3), leadzirconate titanate (PZT), or potassium sodium niobate (KNN).

[0222] Next, in Figure 4A In step 322, such as Figure 14 As shown, conductive material is deposited into the trenches of the second group to form the second finger array 170. (Reference) Figures 3A to 3C The second arm 188 is also formed in this step. Deposition can be performed using CVD, PVD, or other suitable methods. This conductive material is not a piezoelectric material. As shown, a conductive material layer 254 is also formed on the top wafer, including piezoelectric fingers formed in the first finger array 150. In some specific embodiments, the conductive material is polycrystalline silicon.

[0223] exist Figure 4A In step 324, such as Figure 15A and Figure 15B As shown, the conductive material layer is planarized to the location of the first dielectric layer 240. The first dielectric layer acts as an etch stop layer for this step. As shown, after the planarization step, the conductive material layer 254 remains on the piezoelectric fingers in the first finger array 150 within the first set of trenches. Figure 15B As can be seen, the distal ends 160 and 180 of the two finger arrays are inserted between each other.

[0224] exist Figure 4A In step 326, such as Figure 16 As shown, the conductive material layer 254 is further patterned to expose the fingers in the two arrays (the first finger array 150 and the second finger array 170). In other words, the horizontal plane of the conductive material is lowered below the horizontal plane of the first dielectric layer 240. The horizontal plane of the conductive material is also lowered in the other trenches 135, 137, 139, and 143 in the top wafer.

[0225] Next, in Figure 4B In step 328, such as Figure 17As shown, a dielectric layer is formed on the exposed surfaces of the piezoelectric material 252 and the conductive material layer 254. This step can be considered as adding a first dielectric layer 240. In some specific embodiments, this is accomplished by performing thermal oxidation on the exposed surfaces. The operation of adding the first dielectric layer also occurs on other trenches 135, 137, 139, and 143 in the top wafer.

[0226] Next, in Figure 4B In step 330, such as Figure 18 As shown, the first dielectric layer 240 is patterned to expose a portion of the top wafer 110 within the drive comb portion 134. This is done so that the silicon can be removed later, as will be shown later. A portion of the first dielectric layer is removed from the drive comb portion to expose the top wafer.

[0227] Next, in Figure 4B In step 332, such as Figure 19 As shown, a first etch stop layer 256 is deposited on the top wafer. Deposition can be performed using CVD, PVD, or other suitable methods. The first etch stop layer can be made of any material different from the first dielectric layer 240, such as different dielectric or conductive materials. In some specific embodiments, the first etch stop layer is made of polysilicon.

[0228] exist Figure 4B In step 334, such as Figure 20 As shown, a second dielectric layer 258 is formed on the first etch stop layer 256. This can be accomplished by deposition (e.g., CVD, PVD, or other suitable methods). Next, in Figure 4B In step 336, such as Figure 21A and Figure 21B As shown, the second dielectric layer is patterned to expose a portion of the drive comb portion 134, the hub portion 136, and the inner frame portion 138. In other words, the second dielectric layer is removed from these three portions. Therefore, the second dielectric layer 258 remains on a portion of the inner frame portion 138, the spring portion 140, and the outer frame portion 142. In the spring portion 140, the second dielectric layer 258 is present on a central portion 102 aligned with the distal ends of the fingers in the first finger array 150 and the second finger array 170. The first etch stop layer 256 is exposed where the second dielectric layer is removed. Typically, the first dielectric layer 240 and the second dielectric layer 258 are made of the same material.

[0229] Next, in Figure 4B In step 338, such as Figure 22As shown, the second etch stop layer 260 is deposited on the top wafer. Deposition can be performed using CVD, PVD, or other suitable methods. In some specific embodiments, the second etch stop layer is made of the same material as the first etch stop layer 256. As shown, the first etch stop layer 256 and the second etch stop layer 260 are in direct contact with each other at multiple locations in the anchor arm portion 132, the drive comb portion 134, the hub portion 136, and the inner frame portion 138.

[0230] Next, in Figure 4B In step 340, such as Figure 23A and Figure 23B As shown, two etch stop layers are patterned to form vertical spacers 262 within the drive comb portion. As illustrated, spacers 262 are present on a portion of the top wafer 110 located between the first finger array 150 and the second finger array 170 and the trench 135 within the drive comb portion 134. A trench 264 exists between these spacers and is located above the distal end of the first finger array 150 within the drive comb portion 134. Spacers 262 are also present on a first dielectric layer 240 adjacent to the drive comb portion 134. Figure 23B As shown, the second etch stop layer 260 can also be seen on either side of the central portion 102 of the spring portion 140, which is aligned with the distal ends of the fingers in the first finger array 150 and the second finger array 170.

[0231] exist Figure 4B In step 342, such as Figure 24 As shown, the third dielectric layer 270 is deposited on the top wafer 110. Deposition can be performed using CVD, PVD, or other suitable methods. Next, on... Figure 4B In step 344, such as Figure 25A and Figure 25B As shown, the third dielectric layer is patterned to form a vertical dielectric layer 208 in each trench 264. Additionally, the third dielectric layer on the top surface of the top wafer is removed.

[0232] exist Figure 4B In step 346, such as Figure 26 As shown, metal layer 272 is deposited on the top wafer 110. Deposition can be performed using CVD, PVD, or other suitable methods. Next, on... Figure 4B In step 348, such as Figure 27A and Figure 27B As shown, the metal layer is patterned to form a vertical metal layer 206 in each trench 264. This vertical metal layer is adjacent to and in direct contact with a vertical oxide layer in the trench. The combination of the vertical metal layer 206 and the vertical oxide layer, or dielectric layer 208, is also referred to herein as a microspring precursor structure 212 or a vertical composite structure.

[0233] like Figure 27B As shown, the metal layer 272 is also patterned to form metal caps 190 on the distal ends of the first finger array 150 and the second finger array 170. The metal layer is also patterned and retained in the central portion 102 of other grooves 135, 137, 139, and 143 in the drive comb portion 134, hub portion 136, inner frame portion 138, spring portion 140, and outer frame portion 142. Notably, the metal layer 272 has two different heights, which can be achieved through two consecutive masking / etching steps. The location of the microspring precursor structure 212 is illustrated for reference.

[0234] Next, in Figure 4C In step 350, such as Figure 28A and Figure 28B As shown, a passivation layer 200 is formed on the metal cap 190. The passivation layer 200 is also formed on the metal layer 272 in the drive comb portion 134, the hub portion 136, the inner frame portion 138, the spring portion 140, and the outer frame portion 142. The passivation layer can be formed by depositing a fourth dielectric layer and performing a patterning process to remove the fourth dielectric layer from unwanted locations. Although not shown, the passivation layer is also present on the sides of the metal cap 190 and the metal layer 272.

[0235] Next, in Figure 4C In step 352, such as Figure 29A and Figure 29B As shown, a cavity 112 is formed in the top wafer 110 below the first finger array 150 and the second finger array 170. For example, this can be achieved by patterning the top wafer and then using a dry etching process to etch through the exposed vertical spacer 262 and the first dielectric layer 240 below the vertical spacer (see...). Figure 28A and Figure 28B Next, a wet etching process is used to etch the silicon. The wet etching process can be controlled using timing. After the wet etchant has etched through the top wafer, cavity 122 in the bottom wafer provides a volume for collecting and neutralizing the wet etchant. The material of the top wafer in the hub portion 136 and spring portion 140 is also etched. Some undercutting may occur, but this is acceptable. As a result of this etching step, microspring precursor structures 210 and 212 are released from the top wafer and the two etch stop layers. When viewed from above, portions of the bonding layer 130 and the bottom wafer 120 are also visible.

[0236] Next, in Figure 4CIn step 354, annealing is performed. The annealing step can be performed in a heating chamber at a high temperature (e.g., from about 800 °C to about 1,600 °C). Therefore, microsprings 202 and 204 are formed from microspring precursor structures. The resulting micromanipulator array 148 is as follows... Figure 1 As shown.

[0237] In some implementations, such as Figure 1 The package shown can be used as part of a microelectromechanical system (MEMS) actuator. In other embodiments, the bottom wafer 120 is subsequently removed or separated from the top wafer 110. This is indicated as... Figure 4C The optional step 356, and the resulting structural diagram are shown in Figure 30A and Figure 30B middle.

[0238] Any metallic layer discussed herein can generally be formed from any conductive metal or conductive oxide. Examples of suitable metals may include copper, aluminum, nickel, chromium, gold, germanium, silver, titanium, tungsten, platinum, tantalum, ruthenium, cobalt, rhenium, palladium, or zirconium; compounds such as TiN, WN, or TaN; or alloys of the aforementioned, such as AlCu. Examples of suitable conductive oxides may include indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), zinc aluminum oxide (AlZnO), indium oxide (InO), or cadmium oxide (CdO). Metallic or oxide materials can be deposited using methods such as vapor deposition or sputtering, coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), or other suitable methods.

[0239] The structures and methods disclosed herein also involve several different dielectric layers. These dielectric layers can typically be fabricated from any suitable dielectric material or a combination thereof, although the properties of any particular layer can be further defined. Examples of dielectric materials may include silicon dioxide (SiO2), silicon nitride (Si3N4), silicon carbide (SiC), hafnium dioxide (HfO2), zirconium dioxide (ZrO2), aluminum oxide (Al2O3), and silicon oxynitride (SiO2). x N y Hafnium oxide (HfO) x N y ) or zirconium oxynitride (ZrO) x N y Hafnium silicate (HfSi) x O y ) or zirconium silicate (ZrSi) x O y ) or silicon dioxide (SiC) x O y N zAlternatively, it could be hexagonal boron nitride (hBN). Other dielectric materials may include tantalum oxide (Ta2O5), silicon nitride such as nitride, polycrystalline silicon, phosphosilicate glass (PSG), fluorosilicate glass (FSG), undoped silicate glass (USG), high-stress undoped silicate glass (HSUSG), and borosilicate glass (BSG). The dielectric layer can be formed by any suitable method, including chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), thermal oxidation, or other suitable methods.

[0240] It should also be noted that some conventional steps are not explicitly described in the above discussion. For example, a pattern / structure can be formed in a predetermined layer by applying a photoresist layer, patterning the photoresist layer, developing the photoresist layer, and then performing etching to transfer the pattern to the predetermined layer.

[0241] Typically, photoresist layers can be applied, for example, by spin coating or spraying, roller coating, dip coating, or extrusion coating. In spin coating, the substrate is typically placed on a rotating plate, which may include a vacuum chuck to hold the substrate in place. The photoresist composition is then applied to the center of the substrate. The speed of the rotating plate is then increased to evenly distribute the photoresist from the center of the substrate to its periphery. The rotational speed of the plate is then fixed to control the final thickness of the photoresist layer.

[0242] Next, the photoresist composition is baked or cured to remove the solvent and harden the photoresist layer. In some specific embodiments, baking occurs at a temperature of about 90 °C to about 110 °C. A hot plate, oven, or similar apparatus can be used to perform the baking. Thus, a photoresist layer is formed on the substrate.

[0243] The photoresist layer is then patterned by exposing it to radiation. The radiation can be light of any wavelength, with the desired masking pattern. In some specific embodiments, extreme ultraviolet (EUV) light with a wavelength of approximately 13.5 nm is used to perform the patterning process because this allows for smaller feature sizes. Some portions of the photoresist layer are exposed to radiation, while others are not. This exposure causes some portions of the photoresist to dissolve in the developer, while others remain insoluble.

[0244] Following exposure to radiation, an additional photoresist baking step (postexposure bake, PEB) may be performed. For example, this helps release acid leaving groups (ALGs) or other molecules that are important in chemically amplified photoresists.

[0245] Next, the photoresist layer is developed using a developer. The developer can be an aqueous solution or an organic solvent. During development, the soluble portions of the photoresist layer are dissolved and washed away, leaving the photoresist pattern. A common example of a developer is an aqueous solution of tetramethylammonium hydroxide (TMAH). Generally, any suitable developer can be used. Sometimes, baking, or "hard baking," can be performed after development to stabilize the developed photoresist pattern, facilitating optimal performance in subsequent steps.

[0246] Next, portions of the predetermined layer beneath the patterned photoresist layer are exposed. Etching transfers the photoresist pattern to the predetermined layer beneath the patterned photoresist layer. After using the patterned photoresist layer, it can be removed, for example, by using various solvents at high temperatures, such as N-methyl-pyrrolidone (NMP) or alkaline media or other stripping agents, or by using a dry etching process with oxygen plasma.

[0247] Generally, any etching step described herein may be performed using wet etching, dry etching, plasma etching, or a combination thereof, as appropriate, such as reactive ion etching (RIE) or inductively coupled plasma (ICP). Etching can be anisotropic. Depending on the material, etchants may include carbon tetrafluoride (CF4), hexafluoroethane (C2F6), octafluoropropane (C3F8), fluoroform (CHF3), difluoromethane (CH2F2), fluoromethane (CH3F), fluorinated carbon, nitrogen (N2), hydrogen (H2), oxygen (O2), argon (Ar), xenon (Xe), xenon difluoride (XeF2), helium (He), carbon monoxide (CO), carbon dioxide (CO2), fluorine (F2), chlorine (Cl2), hydrogen bromide (HBr), hydrofluoric acid (HF), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), boron trichloride (BCl3), ammonia (NH3), bromine (Br2), or similar substances, or combinations thereof in various proportions. For example, hydrofluoric acid and ammonium fluoride can be used to perform wet etching on silicon dioxide. Alternatively, various mixtures of CHF3, O2, CF4, and / or H2 can be used to perform dry etching on silicon dioxide.

[0248] then, Figure 31A A flowchart of a more general method 360 for manufacturing an array of micromanipulators for microelectromechanical systems actuators is shown according to some embodiments. Figure 31A In step 362, the first finger array 150 is formed from a piezoelectric material on the top wafer 110. This structure is as follows: Figure 13A and Figure 13B As shown.

[0249] exist Figure 31A In step 364, the second finger array 170 is formed from a conductive material on the top wafer 110. The distal ends 160 of the first finger array and the distal ends 180 of the second finger array are interposed between each other. This structure is as follows: Figure 15A and Figure 15B As shown.

[0250] exist Figure 31A In step 366, microspring precursor structures 210 and 212 are formed between the distal ends 160 and 180 of adjacent fingers and on each finger of the first finger array (at its distal end 160). Microspring precursor structure 210 can also be described as being formed on a post 222 located at the ends of the two sets of grooves 230 and 232. This structure is as follows... Figure 9A and Figure 9B As shown.

[0251] exist Figure 31A In step 368, a metal cap 190 is formed, which contacts each finger in the second finger array 170 and each microspring precursor structure 212 on the first finger array. This structure is as follows: Figure 27A and Figure 27B As shown.

[0252] exist Figure 31A In step 370, the top wafer 110 is etched to form a cavity 112 beneath the first finger array and the second finger array. This structure is as follows: Figure 29A and Figure 29B As shown. It is worth noting that the microspring precursor structure 210 and the microspring precursor structure 212 are exposed at this time.

[0253] exist Figure 31A In step 372, annealing is performed to convert each microspring precursor structure into microspring 202 and microspring 204. The resulting structure is as follows: Figure 1 As shown.

[0254] then, Figure 31B A flowchart of another general method 380 for manufacturing a micromanipulator array for microelectromechanical system actuators is shown according to some embodiments. This method is similar to... Figure 31A They are substantially similar. However, in this method, the ratio of the number of fingers in the first finger array to the number of fingers in the second finger array is at least 2:1 and can range from 10:1. In other words, if the number of the first fingers is divided by the number of the second fingers, the quotient is an integer of at least 2. Therefore, both the first finger array 150 and the second finger array 170 can be made of piezoelectric materials, or both can be made of non-piezoelectric conductive materials.

[0255] exist Figure 31B In step 382, ​​a first finger array 150 is formed on the top wafer 110. In step 384, a second finger array 170 is formed on the top wafer 110. The distal ends 160 of the first finger array and the distal ends 180 of the second finger array are interposed between each other. This structure is as follows: Figure 15A and Figure 15B As shown. In some specific embodiments, as described above, the ratio of the number of fingers in the first finger array 150 to the number of fingers in the second finger array 170 is at least 2.

[0256] exist Figure 31BIn step 386, microspring precursor structures 210 and 212 are formed between the distal ends 160 and 180 of adjacent fingers and on each finger of the first finger array (at its distal end 160). In step 388, a metal cap 190 is formed, contacting each finger in the second finger array 170 and each microspring precursor structure 212 on the first finger array. In step 390, the top wafer 110 is etched to form a cavity 112 beneath the first and second finger arrays. In step 392, annealing is performed to convert each microspring precursor structure into microsprings 202 and 204. The resulting structure is as follows: Figure 1 As shown.

[0257] then, Figure 32 This is a plan view of a microelectromechanical system (MEMS) actuator 400 according to some embodiments. The actuator shown includes a four-sided frame 402 surrounding and spaced apart from a sensor connection element 404. The sensor connection element 404 includes a centrally located anchor 406. As shown, four anchor arms 407 extend from the anchor, and together they are considered as an anchor structure 408.

[0258] The sensor connection element can be described as having four quadrants, each located between two anchor arms. Within each quadrant, an anchor arm 407 supports one or more micro-robotic arm arrays 148 within a drive comb section 134, as previously described. As shown, the drive comb section includes two micro-robotic arm arrays, but any number of such arrays may exist. In some specific embodiments, the drive comb section may include one to ten micro-robotic arm arrays. The length of the drive comb section opposite the anchor arm 407 can be used as a support 410. Hinges 412 or cantilevers extend through the open space to connect the supports 410 to non-adjacent corners of the frame 402. A sensor bracket 414 is also provided on each support.

[0259] Box 416 typically indicates Figures 5 to 30B The view relative to the position of the entire actuator, and the above process steps can be applied to the remaining part of the microelectromechanical system actuator. Figure 1 The anchor arm portion 132, drive comb portion 134, pivot portion 136, inner frame portion 138, spring portion 140, and outer frame portion 142 are also shown herein. The anchor arm portion 132 is part of the anchor arm 407. The inner frame portion 138, spring portion 140, and outer frame portion 142 constitute part of the actuator frame 402. The overall dimensions of a microelectromechanical system (MEMS) actuator are typically in the millimeter range, for example, less than 20 mm x 20 mm.

[0260] Microelectromechanical systems (MEMS) actuators can be used for optical image stabilization (OIS). OIS is used to reduce blurring that can occur during exposure due to movement of imaging devices such as binoculars, cameras (handheld, still, or recording), telescopes, and mobile phones / smartphones. This movement causes light initially detected in one pixel to move to adjacent pixels, thus appearing as blur in the captured image. As pixel size decreases, the blur becomes more noticeable at higher resolutions. In this disclosure, OIS is performed by moving the image sensor to compensate for changes in the optical path. This is likely superior to moving the lens because it reduces lens weight and complexity and provides faster compensation (approximately a few milliseconds instead of tens of milliseconds). MEMS actuators can move on all five axes: X-axis, Y-axis, roll, yaw, and pitch.

[0261] Figure 33 A flowchart of a method 440 for stabilizing an optical image against external motion is shown according to some embodiments. This method is performed using a microelectromechanical system actuator, such as... Figure 32 As shown. Some steps of this method are also illustrated in... Figure 34A and Figure 34B middle.

[0262] first, Figure 34A This is a side cross-sectional view of the optical image capturing device 418. As previously described, this device includes a microelectromechanical system (MEMS) actuator 400 located within a housing 420. A sensor connection element 404 is labeled in the figure. Two sensor supports 414 are also shown, and an image sensor 422 is mounted on the MEMS actuator via connections to the sensor supports 414. The image sensor may be, for example, a charge-coupled device (CCD) or an active pixel sensor (CMOS sensor). One or more lenses 424 are present within the housing. The image sensor is located between the lenses and the MEMS actuator, allowing light to fall on it. Herein, the image sensor 422 is in a first position, and an optical path exists between the lenses 424 and the image sensor 422.

[0263] When the device / housing is subjected to external forces, such as shaking in the user's hand, Figure 33 In step 442, the microelectromechanical system (MEMS) actuator is moved to compensate for external forces. This can be achieved, for example, by sending electrical signals to an array of micromanipulators in one or more quadrants to alter the physical distance between interlaced fingers. Figure 34BAs shown, this causes the sensor connection element 404 of the microelectromechanical system actuator 400 to tilt relative to the frame, thereby moving the image sensor 422 to a second position while the optical path still illuminates the same position on the image sensor.

[0264] Microelectromechanical systems (MEMS) are more stable and less prone to damage when their structure includes arrays of microrobotic arms with piezoelectric fingers. The same result occurs when the ratio of the number of fingers between two finger arrays in the microrobotic arm array is greater than 1. This extends the lifespan of the device and improves customer satisfaction.

[0265] This disclosure provides a method for manufacturing a micromanipulator array for use as an actuator in a microelectromechanical system (MEMS). The method includes the following operations: forming a first finger array on a wafer using a piezoelectric material; forming a second finger array on the wafer using a conductive material, wherein a plurality of distal ends of the first finger array and a plurality of distal ends of the second finger array are interposed between each other to form distal ends of a plurality of adjacent fingers interposed with each other; forming a plurality of microspring precursor structures between the distal ends of the adjacent fingers interposed with each other and on each finger in the first finger array; forming a metal cap that contacts each finger in the second finger array and each of the microspring precursor structures on the first finger array; forming a cavity in the wafer below the first and second finger arrays; and performing annealing to convert each of the microspring precursor structures into a microspring. In some embodiments, the piezoelectric material is barium titanate, lead titanate, lead zirconate titanate, or potassium sodium niobate. In some embodiments, the conductive material is polycrystalline silicon. In some embodiments, the metal cap comprises aluminum or an aluminum alloy. In some embodiments, the ratio of the number of fingers in the first finger array to the number of fingers in the second finger array is from 1:1 to 10:1. In some embodiments, the height of the fingers in the second finger array is greater than the height of the fingers in the first finger array. In some embodiments, the width of the fingers in the second finger array is greater than the width of the fingers in the first finger array. In some embodiments, each finger in both the first and second finger arrays is covered by a capping layer. In some embodiments, each of the microspring precursor structures includes an interlocking metal layer and a dielectric layer. In some embodiments, each of the microspring precursor structures between the distal ends of adjacent fingers interlocked with each other is formed by: patterning a wafer to form a groove, the groove including a plurality of pillars spaced apart from each other within the groove; forming a dielectric layer on each of the pillars; and forming a metal layer on each of the pillars to obtain each of the microspring precursor structures between the distal ends of adjacent fingers interlocked with each other. In some embodiments, each of the microspring precursor structures on each finger of the first finger array is formed by: depositing a first etch stop layer on a wafer; depositing a second etch stop layer on a wafer; patterning the first and second etch stop layers to form a plurality of trenches on the distal ends of the first finger array; forming a vertical dielectric layer in each of the trenches; and depositing a metal layer formed as a vertical metal layer in each of the trenches to obtain each of the microspring precursor structures on each finger of the first finger array.

[0266] This disclosure also provides a method for manufacturing a micromanipulator array for a microelectromechanical system actuator. The method includes the following operations: receiving a package including a top wafer bonded to a bottom wafer; patterning the top wafer to form a recess, the recess including a plurality of pillars spaced apart from each other within the recess; forming a dielectric layer on a plurality of exposed surfaces of the recess in the top wafer; forming a plurality of metal layers on the pillars in the recess to form a plurality of horizontal composite structures on the pillars; forming a plurality of sacrificial spacers on the horizontal composite structures; forming a dielectric layer on the plurality of exposed surfaces of the horizontal composite structures and the sacrificial spacers, thereby forming a first set of trenches and a second set of trenches within the recess and forming a first dielectric layer on the top wafer; depositing a piezoelectric material into the first set of trenches to form a first finger array; depositing a conductive material into the second set of trenches to form a second finger array, wherein a plurality of distal ends of the first finger array and a plurality of distal ends of the second finger array are interposed between each other. Multiple vertical composite structures are formed on multiple fingers of a first finger array, each of the vertical composite structures including a dielectric layer bonded to a metal layer. A metal cap is formed, contacting each finger of a second finger array and each of the vertical composite structures on the first finger array. Etching is performed to remove sacrificial spacers and form a cavity within the top wafer. Annealing is performed to transform each of the horizontal composite structures and each of the vertical composite structures into a microspring. In some embodiments, pillars are formed on supports on a base of recesses. In some embodiments, multiple proximal ends of the first finger array extend in a first direction and connect to a first arm, and multiple proximal ends of the second finger array extend in a second direction opposite to the first direction and connect to a second arm. In some embodiments, the method further includes, after depositing conductive material into a second set of trenches to form a second finger array and before forming a vertical composite structure on the fingers of the first finger array: extending a first dielectric layer to multiple top surfaces of the first and second finger arrays; exposing the top wafer in the drive comb portion by removing multiple portions of the first dielectric layer on the top wafer in the drive comb portion; depositing a first etch stop layer on the top wafer; forming a second dielectric layer on the first etch stop layer; patterning the second dielectric layer to expose portions of the drive comb portion, hub portion, and inner frame portion of the top wafer; depositing a second etch stop layer on the top wafer; and patterning the first and second etch stop layers in the drive comb portion to form multiple vertical spacers and to form multiple trenches at the distal ends of the first finger array. In some embodiments, the first and second etch stop layers are made of the same material. In some embodiments, the method further includes forming a passivation layer on a metal cap.

[0267] This disclosure further provides a microelectromechanical system (MEMS) actuator. The MEMS actuator includes an anchor structure and an array of multiple micro-manipulators. The micro-manipulator arrays are connected to the anchor structure, each of the micro-manipulator arrays including a first spacer finger array and a second spacer finger array. The first spacer finger array is formed of a piezoelectric material and extends from a first arm along a first horizontal direction. The second spacer finger array is formed of a conductive material and extends from a second arm along the first horizontal direction, wherein multiple distal ends of the first spacer finger array and multiple distal ends of the second spacer finger array are interposed between each other to form multiple distal ends of adjacent fingers interposed to each other.

[0268] In some embodiments, each of the micromanipulator arrays further includes: a plurality of microsprings connecting the distal ends of adjacent fingers to which they are inserted into each other; metal caps on the distal ends of the first spaced finger array and the second spaced finger array; and a plurality of microsprings connecting the metal caps to the distal ends of the plurality of fingers in the first spaced finger array.

[0269] In some embodiments, the first spaced finger array and the second spaced finger array are located within the drive comb portion, and each of the micromanipulator arrays also includes an anchor arm portion, a pivot portion, an inner frame portion, a spring portion, and an outer frame portion connected to the anchor structure.

[0270] Various embodiments of this disclosure also describe methods for stabilizing optical images against external motion. The method is achieved by moving a microelectromechanical system (MEMS) actuator to compensate for external motion, wherein an image sensor is mounted on the MEMS actuator. The MEMS actuator includes multiple arrays of microrobotic arms connected to an anchor structure, and each arm array has the elements described above.

[0271] This disclosure also relates to optical image capturing devices in various embodiments, the optical image capturing device comprising: an image sensor mounted on a microelectromechanical system (MEMS) actuator; and a lens, wherein the image sensor is located between the lens and the MEMS actuator. The MEMS actuator includes an array of multiple micro-manipulators connected to an anchor structure. Each arm array includes: a first spaced-out finger array formed of a piezoelectric material extending from a first arm along a first horizontal direction; and a second spaced-out finger array formed of a conductive material extending from a second arm along a first horizontal direction. The distal ends of the first and second finger arrays are interposed between each other.

[0272] Some further embodiments of this disclosure also relate to various methods for fabricating micromanipulator arrays for microelectromechanical system actuators. A first finger array is formed on a wafer. A second finger array is formed on the wafer. The distal ends of the first finger array and the distal ends of the second finger array are interleaved. The ratio of the number of fingers in the first array to the number of fingers in the second array is an integer greater than 1. Microspring precursor structures are formed between the interleaved distal ends of adjacent fingers and on each finger of the first finger array. A metal cap is formed, contacting each finger in the second finger array and each microspring precursor structure on the first finger array. Next, a cavity is formed in the wafer beneath the first and second finger arrays. Annealing is performed to convert each microspring precursor structure into a microspring.

[0273] Other embodiments of this disclosure relate to various methods of manufacturing micromanipulator arrays for microelectromechanical system actuators. A package is received, comprising a top wafer bonded to a bottom wafer. The top wafer is patterned to form a recess, the recess comprising a plurality of pillars spaced apart from each other within the recess. A dielectric layer is formed on the exposed surface of the recess of the top wafer. A metal layer is formed on each pillar in the recess to obtain a horizontal composite structure on each pillar. A sacrificial spacer is formed on each horizontal composite structure. A dielectric layer is formed on the exposed surfaces of the horizontal composite structure and the sacrificial spacer, thereby forming a first set of trenches and a second set of trenches within the recess, and a first dielectric layer is formed on the top wafer. A first array of fingers is formed in the first set of trenches. A second array of fingers is formed in the second set of trenches. The distal ends of the first array of fingers and the distal ends of the second array of fingers are staggered. The ratio of the number of fingers in the first array to the number of fingers in the second array is an integer greater than 1. A vertical composite structure is formed on each finger of the first array of fingers. Each vertical composite structure includes a dielectric layer bonded to a metal layer. A metal cap is formed, which contacts each finger in the second finger array and each vertical composite structure on the first finger array. Etching is performed to remove sacrificial spacers and form cavities within the top wafer. Annealing is then performed to transform each horizontal composite structure and each vertical composite structure into a microspring.

[0274] Various embodiments of this disclosure also describe a microelectromechanical system (MEMS) actuator including an anchor structure. Multiple micromanipulator arrays are connected to the anchor structure. Each arm array includes a first finger array and a second finger array. The first finger array, having spaced-apart fingers, extends from a first arm in a first horizontal direction. The second finger array, having spaced-apart fingers, extends from a second arm in a first horizontal direction. The distal ends of the first and second finger arrays are interleaved. The ratio of the number of fingers in the first array to the number of fingers in the second array is an integer greater than 1.

[0275] In a further embodiment of the microelectromechanical system actuator, each arm array further includes: a microspring connecting the distal ends of each group of adjacent fingers interposed therebetween; a metal cap on the distal ends of the first finger array and the second finger array; and a microspring connecting the metal cap to the distal end of each finger of the first finger array.

[0276] Furthermore, the first and second finger arrays are located within the drive comb section. The arm array may also include an anchor arm section, a pivot section, an inner frame section, a spring section, and an outer frame section connected to the anchor structure.

[0277] Various embodiments of this disclosure also describe methods for stabilizing optical images against external motion. This is achieved by compensating for external motion by moving a microelectromechanical system (MEMS) actuator, wherein an image sensor is mounted on the MEMS actuator. The MEMS actuator includes multiple arrays of microrobotic arms connected to an anchor structure. Each arm array has two arrays of fingers. The ratio of the number of fingers in the first array to the number of fingers in the second array is an integer greater than 1.

[0278] Finally, this disclosure also relates to optical image capturing devices in various embodiments, the optical image capturing device comprising: an image sensor mounted on a microelectromechanical system (MEMS) actuator; and a lens, wherein the image sensor is located between the lens and the MEMS actuator. The MEMS actuator includes a plurality of micromanipulator arrays connected to an anchor structure. Each arm array includes: a first spaced-out finger array extending from a first arm in a first horizontal direction; and a second spaced-out finger array extending from a second arm in the first horizontal direction. The distal ends of the first finger array and the distal ends of the second finger array are staggered. The ratio of the number of fingers in the first array to the number of fingers in the second array is an integer greater than 1.

[0279] This disclosure provides a micromanipulator array. The micromanipulator array includes a wafer, a piezoelectric finger array, a conductive finger array, a plurality of microsprings, a metal cap, and a cavity. The piezoelectric finger array is on the wafer. The conductive finger array is on the wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form distal ends of a plurality of adjacent fingers interposed with each other. A plurality of microsprings are located between the distal ends of the adjacent fingers interposed with each other and on each finger in the piezoelectric finger array. The metal cap contacts each finger in the conductive finger array and each of the microsprings on the piezoelectric finger array. The cavity is located in the wafer below the piezoelectric finger array and the conductive finger array. In some embodiments, the ratio of the plurality of fingers in the piezoelectric finger array to the plurality of fingers in the conductive finger array is from 1:1 to 10:1. In some embodiments, the height of the plurality of fingers in the conductive finger array is greater than the height of the plurality of fingers in the piezoelectric finger array. In some embodiments, the width of the plurality of fingers in the conductive finger array is greater than the width of the plurality of fingers in the piezoelectric finger array.

[0280] This disclosure also provides a micromanipulator array. The micromanipulator array includes a package, a piezoelectric finger array, a conductive finger array, a plurality of horizontal microsprings, a plurality of vertical microsprings, a metal cap, and a cavity. The package includes a top wafer bonded to a bottom wafer. The piezoelectric finger array is located in the top wafer. The conductive finger array is located in the top wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form a plurality of distal ends of adjacent fingers interposed with each other, and each finger in the piezoelectric finger array and each finger in the conductive finger array is covered by a dielectric layer. A plurality of horizontal microsprings are located between the distal ends of adjacent interposed fingers, each of the horizontal microsprings including a dielectric layer bonded to a metal layer. A plurality of vertical microsprings are located on the plurality of fingers of the piezoelectric finger array, each of the vertical microsprings including a dielectric layer bonded to a metal layer. The metal cap contacts each finger in the conductive finger array and each of the vertical microsprings in the piezoelectric finger array. The cavity is located within the top wafer. In some embodiments, a plurality of proximal ends of the piezoelectric finger array extend in a first direction and connect to a first arm, and a plurality of proximal ends of the conductive finger array extend in a second direction opposite to the first direction and connect to a second arm. In some embodiments, the micromanipulator array further includes a passivation layer on the metal cap.

[0281] This disclosure further provides a microelectromechanical system (MEMS) actuator. The MEMS actuator includes an anchor structure and an array of multiple micro-manipulators. The micro-manipulator arrays are connected to the anchor structure, each of the micro-manipulator arrays including an array of piezoelectric spacer fingers and an array of conductive spacer fingers. The piezoelectric spacer finger array extends from a first arm along a first horizontal direction. The conductive spacer finger array extends from a second arm along the first horizontal direction, wherein multiple distal ends of the piezoelectric spacer finger array and multiple distal ends of the conductive spacer finger array are interposed between each other to form the distal ends of multiple adjacent fingers interposed with each other. In some embodiments, each of the micro-manipulator arrays further includes: multiple microsprings connecting the distal ends of the adjacent interposed fingers; metal caps on the distal ends of the piezoelectric spacer finger array and the conductive spacer finger array; and multiple microsprings connecting the metal caps to the distal ends of the multiple fingers of the piezoelectric spacer finger array. In some embodiments, the piezoelectric spacer finger array and the conductive spacer finger array are located within the drive comb portion, and each of the micromanipulator arrays also includes an anchor arm portion, a pivot portion, an inner frame portion, a spring portion, and an outer frame portion connected to the anchor structure.

[0282] The foregoing has outlined the features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art should understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to achieve the same objectives and / or advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent architectures do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications can be made to this document without departing from its spirit and scope.

Claims

1. A micro-robotic arm array, characterized in that, include: One wafer; An array of piezoelectric fingers is on the wafer; A conductive finger array is on the wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form a plurality of distal ends of adjacent fingers interposed to each other. Multiple microsprings are located between the distal ends of the multiple adjacent fingers interposed to each other and on each finger in the piezoelectric finger array; A metal cap contacts each of the conductive finger array and each of the plurality of microsprings on the piezoelectric finger array; as well as A cavity is located in the wafer beneath the piezoelectric finger array and the conductive finger array.

2. The micro-robotic arm array as described in claim 1, characterized in that, The ratio of the number of piezoelectric fingers in the array to the number of conductive fingers in the array is 1:1 to 10:

1.

3. The micro-robotic arm array as described in claim 1, characterized in that, The height of one of the multiple fingers in the conductive finger array is greater than the height of one of the multiple fingers in the piezoelectric finger array.

4. The micro-robotic arm array as described in any one of claims 1 to 3, characterized in that, The width of one of the multiple fingers in the conductive finger array is greater than the width of one of the multiple fingers in the piezoelectric finger array.

5. A micro-robotic arm array, characterized in that, include: A package comprising a top wafer bonded to a bottom wafer; An array of piezoelectric fingers is located in the top wafer; A conductive finger array is in the top wafer, wherein a plurality of distal ends of the piezoelectric finger array and a plurality of distal ends of the conductive finger array are interposed between each other to form a plurality of distal ends of adjacent fingers interposed to each other, and each finger in the piezoelectric finger array and each finger in the conductive finger array are covered by a dielectric layer. Multiple horizontal microsprings are positioned between the distal ends of the multiple adjacent fingers, each of the multiple horizontal microsprings including a dielectric layer bonded to a metal layer. Multiple vertical microsprings are located on multiple fingers of the piezoelectric finger array, each of the multiple vertical microsprings including a dielectric layer bonded to a metal layer; A metal cap that contacts each of the conductive finger array and each of the plurality of vertical microsprings on the piezoelectric finger array; as well as A cavity is located within the top wafer.

6. The micro-robotic arm array as described in claim 5, characterized in that, The piezoelectric finger array has multiple proximal ends that extend in a first direction and are connected to a first arm, and the conductive finger array has multiple proximal ends that extend in a second direction opposite to the first direction and are connected to a second arm.

7. The micro-robotic arm array as described in any one of claims 5 to 6, characterized in that, It also includes a passivation layer on the metal cap.

8. A microelectromechanical system actuator, characterized in that, include: One-anchor structure; as well as Multiple micro-robotic arm arrays are connected to the anchor structure, each of the multiple micro-robotic arm arrays comprising: An array of piezoelectric spacer fingers extends from a first arm along a first horizontal direction; as well as A conductive spacer array extending from a second arm along the first horizontal direction, wherein a plurality of distal ends of the piezoelectric spacer array and a plurality of distal ends of the conductive spacer array are interposed between each other to form a plurality of distal ends of adjacent fingers interposed to each other.

9. The microelectromechanical system actuator as described in claim 8, characterized in that, Each of the plurality of micro-robotic arm arrays further includes: Multiple microsprings connecting the distal ends of the plurality of adjacent fingers into which they are inserted; A metal cap is placed on the plurality of distal ends of the piezoelectric spacer finger array and the plurality of distal ends of the conductive spacer finger array; and The metal cap is connected to the multiple microsprings at the multiple distal ends of the multiple fingers of the piezoelectric spacer array.

10. The microelectromechanical system actuator as described in any one of claims 8 to 9, characterized in that, The piezoelectric spacer array and the conductive spacer array are located within a drive comb-shaped portion, and each of the plurality of micro-robotic arm arrays further includes an anchor arm portion, a hub portion, an inner frame portion, a spring portion and an outer frame portion connected to the anchor structure.

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