A flexible integrated array sensor and its wafer-level manufacturing process

Abstract

The present invention provides a flexible integrated array sensor and a manufacturing process thereof, which belongs to the field of flexible sensor technology. The array sensor includes a silicon wafer and a readout circuit layer, a sensor array layer and a polymer substrate layer located on the silicon wafer. The manufacturing process includes: providing a silicon wafer, and making a plurality of integrated array sensors consisting of m*n sensor units on the surface of the silicon wafer; etching deep grooves on the surface of the silicon wafer between each array sensor; making a thinning support on the surface of the silicon wafer, and thinning the back of the silicon wafer to a target thickness so that the silicon wafers where each array sensor is located are separated from each other; wherein the etching depth of the deep groove is equal to or greater than the target thickness of the silicon wafer after thinning. The manufacturing process can overcome the technical difficulties of the existing use of silicon-based materials to make flexible array sensor arrays, such as the easy warping and cracking of the chip after thinning and the large mechanical slicing damage.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible array sensors, and in particular to a flexible integrated array sensor and a wafer-level manufacturing process thereof. Background Art

[0002] At present, flexible sensors have been widely used in human-computer interaction, robot electronic skin, biomedicine and health care. The sensing units that make up the flexible sensors can be divided into many types according to the measurement object, such as pressure, flow, temperature, gas, etc., and can also be divided into many types according to the sensitive mechanism, such as piezoresistive, capacitive, piezoelectric, etc. For example, piezoelectric flexible sensors use the piezoelectric effect of sensitive materials. When external force acts on the sensitive material, the structure deforms, causing positive and negative bound charges to appear on its surface, thereby sensing external pressure information.

[0003] Among the many types of flexible sensors, no matter what kind of sensitive mechanism the sensor unit belongs to or what kind of measurement object it faces, it needs to be processed by the readout circuit and then sent to the back-end circuit system for analysis. It is easy to understand that in order to enable the sensor to respond to external signals over a large area and enable the back-end system to detect complex external information, its core structure is usually an array (or dot matrix) mode built by several sensor units, and each sensor unit needs to be configured with a corresponding readout circuit to respond to the external signal acting on it. This determines that the sensor unit as a sensitive detection and the readout circuit as an amplification or signal conditioning function always appear together in the sensor array and will continue to increase with the increase of the array size. However, the current development status of flexible array sensors is:

[0004] On the one hand, organic thin film transistors are widely used in the field of flexible electronics due to their good flexibility, low cost, and simple process. Therefore, based on the flexible requirements of sensors, most of them use organic thin film transistors to make readout circuits. However, the carrier mobility of organic materials is low, which leads to low sampling frequency and cannot meet the detection of high-frequency signals. On the other hand, in most of the flexible array sensors reported so far, the internal sensing unit is separated from its readout circuit. Most of them are manufactured by printed electronics or transfer technology and are electrically connected to the readout circuit through leads to transmit signals. It is understandable that as the size of the array increases, the number of leads increases (because the readout circuit connected to each sensing unit in the array requires at least two leads), resulting in a complex circuit structure, more noise and crosstalk, and is not conducive to improving the spatial resolution of the sensor.

[0005] In addition, from the perspective of the manufacturing process of flexible sensors, the current mainstream method is to print organic or amorphous materials directly onto a flexible substrate through printed electronics or transfer technology, which can be produced on a large scale at low cost. However, compared with traditional silicon-based materials, organic or amorphous materials have lower carrier mobility, which restricts the operating frequency and performance of the device. Moreover, in the current technical background where the wafer-level semiconductor manufacturing process is quite mature, although it is well known that traditional silicon-based materials have higher carrier mobility, using silicon-based materials to make readout circuits can bring better sampling frequency and operating speed to sensors, it is still rare to use silicon-based materials to make highly integrated, highly sensitive flexible array sensors that integrate readout circuits and sensor units. The reason is that the process is difficult and it is difficult to thin the rigid and brittle silicon material to a certain thickness to make it completely conformal and flexible (because the target thickness of wafer thinning is extremely small, and the film stress generated by the process will cause the thinned chip to warp or break), and the mechanical dicing step after thinning is also easy to damage the device, thereby greatly reducing the device yield and increasing costs. Summary of the invention

[0006] The first objective of the present invention is to provide a flexible integrated array sensor in view of the above-mentioned deficiencies existing in the prior art, which is used to solve the problems existing in the prior flexible array sensors, such as the large number of connecting leads between the sensing unit and the readout circuit, the large noise and crosstalk, and the low sampling frequency and weak high-frequency signal detection capability caused by the use of organic thin film transistors to make the readout circuit.

[0007] The second purpose of the present invention is to provide a manufacturing process for a flexible integrated array sensor, which is used to replace the transfer or printing manufacturing methods of traditional flexible sensors and overcome the technical difficulties of existing flexible array sensors made of silicon-based materials, such as easy warping and cracking of chips after thinning and severe mechanical slicing damage.

[0008] To achieve the above first purpose, the present invention adopts the following technical solution:

[0009] A flexible integrated array sensor, comprising:

[0010] A readout circuit layer, which is constructed on a silicon wafer suitable for flexible applications and includes a plurality of readout circuit units;

[0011] The sensing array layer is stacked with the readout circuit layer and includes a plurality of sensing units, each of which is connected to a readout circuit unit via a conductive tungsten plug to form a detection unit. These detection units are distributed in an m*n array on the silicon wafer to form a detection array.

[0012] Furthermore, the flexible integrated array sensor also includes a polymer substrate layer, which includes a top polymer substrate covering the detection array; or further includes: a bottom polymer substrate covering the side of the silicon wafer away from the detection array.

[0013] Furthermore, the flexible integrated array sensor also includes: a polymer passivation layer, which is constructed between the top polymer substrate and the detection array, and the polymer passivation layer includes a plurality of contact holes, and electrical connection between two or more separated detection arrays is achieved through the contact holes and connecting metals.

[0014] To achieve the above second purpose, the present invention adopts the following technical solution:

[0015] A wafer-level manufacturing process for a flexible integrated array sensor, comprising:

[0016] S1. Provide a silicon wafer, and manufacture a plurality of detection arrays consisting of m*n detection units on the surface of the silicon wafer by semiconductor process;

[0017] S2, performing deep groove etching on the surface of the silicon wafer between the detection arrays to separate the detection arrays from each other, wherein the etching depth is equal to or greater than the target thickness of the silicon wafer after subsequent thinning;

[0018] S3, forming a top polymer substrate layer above each detection array and patterning it, then forming a thinning support on the patterned top polymer substrate layer, thinning the back side of the silicon wafer to a target thickness so that the silicon wafers where the detection arrays are located are separated from each other;

[0019] S4. Remove the thinning support and release the obtained flexible integrated array sensor.

[0020] Furthermore, in S3, before making the top polymer substrate layer, the following steps may be included:

[0021] First, a polymer passivation layer is formed on each detection array and contact holes are opened thereon, and at least two mutually separated detection arrays are electrically connected through connecting metals by using the contact holes; then a top polymer substrate layer is formed on the polymer passivation layer and both are patterned together.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The flexible integrated array sensor provided by the present invention uses silicon-based materials to make the readout circuit. Compared with ordinary organic materials, it has high carrier mobility, higher sampling frequency and operating speed, and significantly improved sensitivity.

[0024] 2. The flexible integrated array sensor provided by the present invention forms a detection array by stacking a silicon-based readout circuit and a sensor array. Compared with the existing flexible integrated array sensors, the number of leads is reduced and the circuit structure is greatly optimized, thereby realizing the single-chip integration of the sensor array and the readout circuit, effectively improving the sensor's gain, spatial resolution, signal-to-noise ratio and anti-interference ability, and being more convenient for application in multiple high-end fields such as electronic skin and bionic robots.

[0025] 3. The manufacturing process of the flexible integrated array sensor described in the present invention adopts a wafer-level preparation method, which etches deep grooves equal to or slightly larger than the target thickness between the detection arrays on the silicon wafer, so that the film stress can be released when the back of the silicon wafer is thinned to prevent the chip from warping or cracking after thinning, and the device can be released after the thinning process without mechanical dicing, thereby avoiding the damage to the wafer caused by the traditional dicing process; at the same time, the setting of the polymer passivation layer with contact holes can realize the electrical connection between the separated detection arrays with different sensitive mechanisms and / or different performances through connecting metals, effectively improving the feasibility of preparing multifunctional flexible silicon-based devices.

[0026] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic structural diagram of a flexible integrated array sensor with a single-function detection array according to Embodiment 1 of the present invention;

[0028] Figure 2 for Figure 1 The flexible integrated array sensor shown is a schematic cross-sectional view of the structure of the detection unit;

[0029] Figure 3 It is a cross-sectional schematic diagram of each step of preparing the flexible integrated array sensor with a single function detection array of Example 1 of the present invention;

[0030] Figure 4 This is a schematic structural diagram of a flexible integrated array sensor with a dual-function detection array according to a second embodiment of the present invention;

[0031] Figure 5 for Figure 4 The flexible integrated array sensor shown is a schematic cross-sectional view of the detection unit structure;

[0032] Figure 6 It is a cross-sectional schematic diagram of each step of preparing the flexible integrated array sensor with a dual-function detection array of Example 2 of the present invention.

[0033] Among them, 100 silicon wafer; 110 deep groove; 200 detection array; 200a detection unit; 300 support wafer; 310 bonding material; 210 readout circuit layer; 211 readout circuit unit; 220 dielectric layer; 221, 222 conductive tungsten plugs; 230 piezoelectric sensor array layer; 231 piezoelectric sensor unit; 231a upper electrode layer; 231b lower electrode layer; 231c piezoelectric material layer; 240 first connection metal; 250 polymer; 251 first contact hole; 260 polymer material passivation layer; 261 second contact hole; 262 second connection metal; 270 top polymer substrate layer; 280 bottom polymer substrate layer; 290 pad. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and functions of the present invention clearer and easier to understand, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments:

[0035] Based on the shortcomings of the background technology of the present invention, the present invention provides a flexible integrated array sensor that does not require complex wires to connect the sensing unit and the readout circuit unit. The array sensor can be a microsensor prepared by semiconductor technology to measure different objects with different sensitive mechanisms as a sensing unit. Regardless of the type of microsensor used as the sensing unit, the changes of the external measured object by the sensing unit can be converted into charge, current or voltage changes received and responded by its readout circuit, and signal conditioning is performed and sent to the back-end system to detect external information.

[0036] Embodiment 1

[0037] The present invention proposes a flexible integrated array sensor with a single detection array, and illustrates the concept of the present invention by using a micro pressure sensor with a piezoelectric measurement mechanism as a sensing unit in the detection array. This embodiment realizes single function detection of the flexible array sensor.

[0038] like Figure 1-2 As shown, the present invention provides a flexible integrated array sensor, which includes a readout circuit layer 210 constructed on a silicon wafer 100 suitable for flexible applications, which includes a plurality of readout circuit units 211; and a piezoelectric sensor array layer 230 constructed on the readout circuit layer 210, which includes a plurality of piezoelectric sensor units 231, each piezoelectric sensor unit 231 is connected to a readout circuit unit 211 through conductive tungsten plugs 221, 222 to form a detection unit 200a, and these detection units 200a are distributed in an m*n array on the silicon wafer to form a detection array 200( Figure 1The detection units 200a are arranged in a 3*2 array as a schematic diagram of the detection array 200). The manufacturing method of the conductive tungsten plugs 221 and 222 includes but is not limited to first constructing a dielectric layer 220 on the readout circuit layer 210, and then constructing a plurality of conductive tungsten plugs 221 and 222 connected to each readout circuit unit 211 in the dielectric layer 220. The dielectric layer 220 is preferably made of silicon dioxide, silicon nitride or silicon oxynitride.

[0039] Based on the above-mentioned structure of the present invention, the sensing unit in the detection array can achieve a spatial resolution of less than 1mm. Among them, each readout circuit unit 211 in the readout circuit layer 210 is a micro-integrated circuit made by semiconductor technology, preferably any one of CMOS circuit, bipolar circuit or thin film transistor circuit, which can be determined according to the specific implementation. Its production method can be completed by oxidation, etching, photolithography, ion implantation and other processes of silicon wafer. Its main function is to be used for signal reading and subsequent signal conditioning, responding to the pressure signal of the piezoelectric sensing unit and converting it into a voltage signal (or current signal) that can be recognized and received by the back-end system. In addition, the silicon wafer suitable for flexible applications is a thin silicon wafer with a thickness of less than 100μm, which can be obtained by a mature thinning process.

[0040] In the above scheme, the present invention uses silicon-based materials as substrates, and uses semiconductor process technology to manufacture a readout circuit layer composed of several readout circuit units and a piezoelectric sensor array layer composed of several piezoelectric sensor units, and establishes a one-to-one connection relationship between them to form a detection array. When applied, when one or several sensor units in the piezoelectric sensor array layer detect contact pressure, they will be quickly responded to by the corresponding silicon-based readout circuit unit by generating positive and negative induced charges, and sent to the back-end system for processing. This technical means of integrating the readout circuit unit and the sensor unit in a single chip in the vertical direction can be prepared through mature semiconductor processes, which can not only reduce the number of leads and simplify the circuit structure to solve the circuit complexity problem caused by the traditional lead connection integration means, but also solve the problems of low sampling frequency and weak high-frequency signal detection capability existing in traditional organic readout circuits based on the high carrier mobility characteristics of silicon-based materials.

[0041] The further implementation details of this embodiment are: Figure 2As shown, two groups of conductive tungsten plugs 221 and 222 are constructed in the dielectric layer 220 corresponding to each readout circuit unit 211; wherein each piezoelectric sensing unit 231 includes an upper electrode layer 231a, a piezoelectric material layer 231c and a lower electrode layer 231b distributed from top to bottom, and the lower electrode layer 231b of each sensing unit is directly connected to the first wiring part of the corresponding readout circuit unit 211 through a group of conductive tungsten plugs 221, and the upper electrode layer 231a of each sensing unit is indirectly connected to the second wiring part of the corresponding readout circuit unit 211 through a group of conductive tungsten plugs 222, as shown in FIG. Figure 2 As shown. That is, a readout circuit unit 211 is connected to the upper electrode layer 231a and the lower electrode layer 231b of a piezoelectric sensing unit 231 through two groups of tungsten plugs 221 and 222 respectively. Among them, the upper electrode layer 231a and the lower electrode layer 231b are preferably made of molybdenum, titanium, aluminum, copper, tantalum or gold, and the two can use the same or different electrode materials. The piezoelectric material layer 231c is used as the sensitive material of the entire sensing array. It preferably uses a piezoelectric film composed of lead zirconate titanate, aluminum nitride, scandium-doped aluminum nitride or zinc oxide. When external pressure acts on it, equal positive and negative charges will be generated in the upper electrode layer 231a and the lower electrode layer 231b, respectively, and then sent to the corresponding readout circuit unit 211 through the connected conductive tungsten plugs 221 and 222.

[0042] As mentioned above, the upper electrode layer 231a of the piezoelectric sensor unit 231 is indirectly connected to the readout circuit unit 211 through the tungsten plug 222. Figure 2 As shown, one of the implementation methods is provided in the present invention, that is, the connection between the upper electrode layer 231a of the piezoelectric sensing unit 231 and the corresponding tungsten plug 222 is realized by using the connecting metal 240. Here, the use of the connecting metal 240 is a conventional method in the semiconductor manufacturing process, so it is not described in detail. After the above structural arrangement, the lower electrode layer 231b of each piezoelectric sensing unit 231 is connected to the first wiring part of the corresponding readout circuit unit through a group of tungsten plugs 221, and the upper electrode layer 231a of each piezoelectric sensing unit 231 is connected to the second wiring part of the corresponding readout circuit unit through the connecting metal 240 and another group of tungsten plugs 222. At this point, the connection relationship of "one piezoelectric sensing unit 231 is connected to one readout circuit unit 211" is established, thereby forming a detection array 200 composed of m*n detection units 200a on the silicon wafer.

[0043] The further implementation details of this embodiment are: Figure 2As shown, the flexible integrated array sensor further includes a polymer substrate layer, and the polymer substrate layer may only include a top polymer substrate layer 270 covering the detection array 200, or may also include a bottom polymer substrate layer 280 constructed on the side of the silicon wafer away from the detection array 200. In this embodiment, the top polymer substrate layer 270 and the bottom polymer substrate layer 280 are preferably both (such as Figure 2 Here, the polymer substrate layer is attached to the corresponding layer by conventional spin coating or deposition technology. The present invention does not involve specific improvements, so it is not described in detail. In the specific implementation, the polymer substrate layer material can be selected from any one or combination of polyimide, polyester, polyurethane, ethylene-vinyl acetate copolymer, polyolefin, epoxy resin, polycarbonate, polyamide, acrylic resin, silicone resin, and parylene materials. The above-mentioned parylene materials can be used by technicians in the specific implementation of Parylene C, Parylene D, Parylene F, Parylene N, Parylene HT, etc.

[0044] like Figure 3 As shown, the present invention further provides a semiconductor manufacturing process for manufacturing a flexible integrated array sensor with a single function detection array, and uses a cross-sectional schematic diagram of each step when two detection units in a row direction / column direction in the detection array are formed on a silicon wafer as an explanation. Figure 3 Understand the following manufacturing steps of the present invention:

[0045] S1. Provide a silicon wafer 100, and manufacture a plurality of detection arrays 200 consisting of m*n detection units 200a on the surface of the silicon wafer 100 by semiconductor technology; wherein each detection array 200 comprises:

[0046] - S11, a readout circuit layer 210 including a plurality of readout circuit units 211 is fabricated on the surface of the silicon wafer 100 (see Figure 3 S111), and the conductive tungsten plugs 221, 222 (see Figure 3 S112);

[0047] S12, a piezoelectric sensing unit 231 is fabricated on the readout circuit layer 210, and a piezoelectric sensing array layer including m*n piezoelectric sensing units 231 is formed by patterning, and then each electrode of each piezoelectric sensing unit is connected to the corresponding readout circuit unit 211 directly or by using a connecting metal 240 through conductive tungsten plugs 221, 222 to form a plurality of detection units 200a, thereby obtaining the detection array 200 (see Figure 3 (see S121-S124).

[0048] S2, etching deep grooves 110 on the surface of the silicon wafer 100 between the detection arrays 200 to separate the detection arrays 200 from each other, wherein the etching depth is equal to or greater than the target thickness of the silicon wafer 100 after subsequent thinning;

[0049] S3, making a top polymer substrate layer 270 above each detection array 200 (see Figure 3 S31) and graphically represent it (see Figure 3 S32), and then a thinning support is made on the patterned top polymer substrate layer 270 (see Figure 3 In S33), the back side of the silicon wafer 100 is thinned to a target thickness so that the silicon wafers where the detection arrays 200 are located are separated from each other (see Figure 3 S34);

[0050] S4, spin coating or depositing a bottom polymer substrate layer 280 on the back of the thinned silicon wafer 100 (see Figure 3 S41 in FIG. 4 and patterning it to match the top polymer substrate layer 270 (see FIG. Figure 3 S42 in the figure), then the thinning support is removed and the flexible integrated array sensor is released (see Figure 3 (S43).

[0051] Explanation of S1 above: S11 "constructing conductive tungsten plugs 221, 222 connected to each readout circuit unit 211" specifically includes firstly manufacturing a dielectric layer 220 on the readout circuit layer, and constructing two sets of tungsten plugs 221, 222 connected to two wiring locations of each readout circuit unit 211 in the dielectric layer 220 (see Figure 3 S12 can be specifically implemented as follows: a lower electrode layer 231b, a piezoelectric material layer 231c, and an upper electrode layer 231a are sequentially formed on the dielectric layer 220 (see Figure 3 S121), a piezoelectric sensor array layer 230 including m*n mutually separated piezoelectric sensor units 231 is formed by patterning (see Figure 3 In step S122), each lower electrode layer 231b is directly connected to the first wiring part of the corresponding readout circuit unit 211 through the conductive tungsten plug 221, and then a connecting metal 240 is made to connect the upper electrode layer 231a and the conductive tungsten plug 222 so that each upper electrode layer 231a is connected to the second wiring part of the readout circuit unit 211, thereby forming a detection array composed of m*n detection units. When making the connecting metal 240, a layer of polymer 250 (see Figure 3In S123), the polymer 250 forms a first contact hole 251 at the upper electrode layer 231a of each piezoelectric sensor unit 231 and the corresponding conductive tungsten plug 222, and then the first connection metal 240 is connected between the first contact holes 251 of the two (see Figure 3 (S124).

[0052] Explanation of S2 above: The etching method for the deep groove 110 of the silicon wafer can preferably adopt the relatively mature ion beam etching method or reactive ion etching method, which will not be described in detail here. It can be understood that the multiple detection arrays 200 are synchronously formed on the silicon wafer 100 as a whole through semiconductor technology, so the deep groove etching of the silicon wafer 100 between each detection array 200 will separate the detection arrays from each other (combined with Figure 3 (understood in S2).

[0053] Explanation of S3 above: A thinning support is made on the surface of the silicon wafer 100. The present invention preferably adopts an implementation method of temporarily bonding another silicon wafer (hereinafter referred to as the support wafer 300) through a bonding material 310 (refer to Figure 3 S33). Its purpose is to facilitate the thinning process on the back side of the silicon wafer 100, because the target thickness of the silicon wafer 100 to be thinned is extremely small, and the etching of the deep groove 110 has pre-divided each array device. Therefore, it is necessary to provide a hard support for each array device before thinning the back side of the silicon wafer 100 to smoothly complete the thinning. As for the specific thinning technology and temporary bonding technology, the existing mature semiconductor process can be used. The present invention does not make any improvements to the thinning technology and temporary bonding technology, so it will not be described in detail. For example, the most commonly used silicon wafer back thinning technology includes grinding, chemical mechanical polishing, wet etching, plasma etching and dry polishing. In addition, the aforementioned "thinning support" can also be replaced by pasting a blue film in the specific implementation. If a temporary bonding support wafer 300 is adopted, it is only necessary to debond and remove the thinning support to release the flexible integrated array sensor with a single function detection array.

[0054] Explanation of the above S3 and S4: The two "patterning" processes of the polymer substrate layer in the present invention are both for removing the polymer substrate covering the deep grooves in the detection array spacing area (refer to Figure 3S32, S42), so that after thinning, the device can be released smoothly to obtain a flexible integrated array sensor with a single function detection array. It can be understood that the locations of the two "patterning" processes are the deep groove etching locations on the silicon wafer. It is worth noting that the aforementioned bottom polymer substrate layer 280 can be omitted in the specific implementation, and only the top polymer substrate layer 270 is retained. The present invention adopts a more preferred implementation method in this embodiment (that is, both the top polymer substrate layer 270 and the bottom polymer substrate layer 280 are made). In addition, when the top polymer substrate layer 270 is patterned, it is usually also included to make a pad 290 for connecting the sensor to an external system (refer to Figure 3 In S32), since this part can be implemented and understood by those skilled in the art based on mature processes, it will not be described in detail.

[0055] In the above process provided in this embodiment of the present invention, a plurality of detection arrays 200 consisting of m*n detection units 200a are first fabricated on a silicon wafer 100 (taking a piezoelectric micro pressure sensor as an example, each detection unit 200a includes a piezoelectric sensing unit 231 and a corresponding readout circuit unit 211), and then deep grooves equal to or slightly larger than the target thickness are etched between the detection arrays 200 (refer to Figure 3 ): On the one hand, it can release the film stress generated during the thinning process of the silicon wafer 100 to prevent the silicon wafer from warping and cracking; on the other hand, it eliminates the dicing step after the traditional silicon wafer is thinned, so that the devices made on the silicon wafer 100 can be released without mechanical dicing, effectively avoiding the damage to the wafer caused by the traditional dicing process. Such an innovative process provides the possibility for the application of silicon-based materials in the field of flexible integrated sensing. The target thickness of the silicon wafer 100 after thinning described in the present invention is less than 100μm. Wafers of this thickness have good flexibility, which effectively improves the feasibility of preparing flexible integrated sensor arrays.

[0056] After the above-mentioned manufacturing, the flexible array sensor with a single-function detection array manufactured by the present invention has a stacked structure of the piezoelectric sensing unit 231 and the readout circuit unit 211 inside the device. Such an array sensor not only greatly improves the integration level, but also solves many problems that trouble R&D workers, such as complex circuit structure, noise, interference, etc., caused by too many leads, and provides a basis for the manufacture of integrated piezoelectric array sensors.

[0057] It should also be noted that the various graphic processes used in the present invention when manufacturing the array sensor all adopt mature wafer-level semiconductor manufacturing technology, and the various etchants used are actually selected according to different materials to be etched and are readily available materials, so no additional explanation is given.

[0058] Embodiment 2

[0059] like Figure 4-5 As shown, the present invention provides a flexible integrated array sensor having two different detection arrays 200, 200', which is different from the first embodiment in that the flexible integrated array sensor can at least realize dual-function detection, that is, during the specific production, it is only necessary to construct the sensing array layers in the two detection arrays into microsensors with different sensitive mechanisms and / or different performances. Figure 4-5 As can be seen, the left detection array 200 has a detection unit 200a, and the right detection array 200' has a detection unit 200a', and the two have different sensing units. It can be understood that those skilled in the art can refer to the ideas given in this embodiment to manufacture a flexible array sensor with more than two different detection arrays.

[0060] like Figure 4-5 , which shows a flexible integrated array sensor having two different detection arrays 200, 200', which is different from the first embodiment in that a polymer passivation layer 260 is constructed between the top polymer substrate 270 and the detection array 200, and a plurality of second contact holes 261 are opened on the polymer passivation layer 260 (refer to Figure 6 ), the electrical connection between two (or more) mutually separated detection arrays is realized through the second contact hole 261 and the second connection metal 262. That is, relative to the first embodiment, the second embodiment structurally only adds a layer of polymer passivation layer 260 and utilizes the second contact hole 261 on the passivation layer to realize the electrical connection between two mutually separated detection arrays through the second connection metal 262. Other structural designs remain unchanged and will not be elaborated here. The polymer passivation layer 260 may also preferably adopt any one of polyimide, polyester, polyurethane, ethylene-vinyl acetate copolymer, polyolefin, epoxy resin, polycarbonate, polyamide, acrylic resin, silicone resin, and parylene materials in specific implementation.

[0061] In terms of specific manufacturing process, the main difference between the second embodiment and the first embodiment is step 3 S3'. Figure 6 In the above S3', before making the top polymer substrate layer 270, it also includes: first making a polymer passivation layer 260 above each detection array 200 (see Figure 6 S31') and a second contact hole 261 is opened thereon (see Figure 6 The second contact hole 261 is used to electrically connect the two separated detection arrays 200 through the second connection metal 262 (see Figure 6 Then, a top polymer substrate layer 270 is formed on the polymer passivation layer 260 (see Figure 6 S34') and graphically represent both (see Figure 6 S35'). Figure 6 As shown in S35 ′, patterning the polymer passivation layer 260 and the top polymer substrate layer 270 also includes making pads 290 for connecting the sensor to an external system.

[0062] Here, the polymer passivation layer 260 and the top polymer substrate layer 270 are patterned together in order to remove the portions covering the deep grooves so as to release the device smoothly after thinning and obtain a flexible integrated array sensor with two different detection arrays. As for the specific patterning positions, those skilled in the art can flexibly select them according to the number and distribution of detection arrays required by the target flexible array sensor during implementation. Figure 4-5 Only a schematic diagram of a flexible array sensor structure having two different detection arrays 200 and 200 ′ is shown for illustration.

[0063] When the polymer passivation layer 260 and the top polymer substrate layer 270 are patterned and the pad 290 is also made, the subsequent thinning support making and wafer backside thinning steps are repeated. Figure 6 After the thinning is completed, the following steps may also include S4': spin coating or depositing a bottom polymer substrate layer 280 (see FIG. 2 ) on the back of the thinned silicon wafer 100. Figure 6 S41') and patterned to match the top polymer substrate layer 270 (see Figure 6 S42'), then remove the thinning support (see Figure 6 In S43'), a flexible integrated array sensor with a dual-function detection array is released. It is worth noting that if a person skilled in the art needs to prepare a flexible array sensor with two or more different detection arrays, then S1' involves flexible selection according to the semiconductor process required by different sensing units, and the present invention provides Figure 4-6 It is only a schematic representation of the sensor unit.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A flexible integrated array sensor, characterized in that: include: A readout circuit layer, which is constructed on a silicon wafer suitable for flexible applications and includes a plurality of readout circuit units; A sensor array layer, which is stacked with the readout circuit layer and includes a plurality of sensor units, each of which is connected to a readout circuit unit via a conductive tungsten plug to form a detection unit, and these detection units are distributed in an m*n array on the silicon wafer to form a detection array; Wherein, the silicon wafer suitable for flexible applications is a thin silicon wafer with a thickness of less than 100 μm; The readout circuit unit is a micro integrated circuit manufactured using semiconductor technology.

2. A flexible integrated array sensor as claimed in claim 1, characterized in that: The sensing units in the sensing array layer are microsensors made by semiconductor technology; each sensing unit includes at least two electrodes, and each electrode is connected to the corresponding readout circuit unit directly or through a conductive tungsten plug using a connecting metal.

3. A flexible integrated array sensor as claimed in claim 1 or 2, characterized in that: Also included is a polymer substrate layer, the polymer substrate layer comprising: A top polymer substrate, which covers the detection array; or further includes: A bottom polymer substrate is constructed covering a side of the silicon wafer facing away from the detection array.

4. A flexible integrated array sensor as claimed in claim 3, characterized in that: Also includes: The polymer passivation layer is constructed between the top polymer substrate and the detection array. The polymer passivation layer includes a plurality of contact holes. The electrical connection between two or more detection arrays separated from each other is realized through the contact holes and the connecting metal.

5. A flexible integrated array sensor as claimed in claim 4, characterized in that: Materials used to make the polymer substrate layer and the polymer passivation layer include polyimide, polyester, polyurethane, ethylene-vinyl acetate copolymer, polyolefin, epoxy resin, polycarbonate, polyamide, acrylic resin, silicone resin, parylene-based materials, etc.

6. The flexible integrated array sensor according to claim 2, characterized in that: The electrode material of the sensor unit includes molybdenum, titanium, aluminum, copper, tantalum, gold, etc.

7. The flexible integrated array sensor according to claim 1, characterized in that: The micro integrated circuit adopts a CMOS circuit, a bipolar circuit or a thin film transistor circuit.

8. A wafer-level manufacturing process for a flexible integrated array sensor according to any one of claims 1 to 7, characterized in that: include: S1. Provide a silicon wafer, and manufacture a plurality of detection arrays consisting of m*n detection units on the surface of the silicon wafer by semiconductor process; S2, performing deep groove etching on the surface of the silicon wafer between the detection arrays to separate the detection arrays from each other, wherein the etching depth is equal to or greater than the target thickness of the silicon wafer after subsequent thinning; S3, forming a top polymer substrate layer above each detection array and patterning it, then forming a thinning support on the patterned top polymer substrate layer, thinning the back side of the silicon wafer to a target thickness so that the silicon wafers where the detection arrays are located are separated from each other; S4. Remove the thinning support and release the obtained flexible integrated array sensor.

9. The wafer-level manufacturing process of a flexible integrated array sensor according to claim 8, characterized in that: In S1, the method of manufacturing a detection array consisting of m*n detection units on the surface of a silicon wafer includes: S11, manufacturing a readout circuit layer including a plurality of readout circuit units on the surface of the silicon wafer, and constructing a conductive tungsten plug connected to each readout circuit unit; S12, manufacturing sensing units on the readout circuit layer, and forming a sensing array layer including m*n sensing units by graphic processing, and then connecting each electrode of each sensing unit to the corresponding readout circuit unit directly or through a conductive tungsten plug using a connecting metal to obtain the detection array.

10. The wafer-level manufacturing process of a flexible integrated array sensor according to claim 8 or 9, characterized in that: In S2, the deep trench etching method includes ion beam etching and reactive ion etching.

11. The wafer-level manufacturing process of a flexible integrated array sensor according to claim 8 or 9, characterized in that: In S3, before making the top polymer substrate layer, the following steps may also be included: First, a polymer passivation layer is formed on each detection array and contact holes are opened thereon, and at least two mutually separated detection arrays are electrically connected through connecting metals by using the contact holes; then a top polymer substrate layer is formed on the polymer passivation layer and both are patterned together.

12. The wafer-level manufacturing process of a flexible integrated array sensor according to claim 11, characterized in that: In S4, before removing the thinning support, the following steps may also be included: A bottom polymer substrate layer is spin-coated or deposited on the back of the thinned silicon wafer and patterned to match the top polymer substrate layer.

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