CN109721023B

CN109721023B - Flexible sensor array, palpation probe and preparation method thereof

Info

Publication number: CN109721023B
Application number: CN201910003796.9A
Authority: CN
Inventors: 宋军华; 王洪超; 何常德; 薄云峰; 吴远星; 薛黄琦; 王晓琴; 何静
Original assignee: Beijing Xiantong Kangqiao Medicine Science & Technology Co ltd
Current assignee: Beijing Xiantong Kangqiao Medicine Science & Technology Co ltd
Priority date: 2019-01-03
Filing date: 2019-01-03
Publication date: 2020-08-28
Anticipated expiration: 2039-01-03
Also published as: CN109721023A

Abstract

The invention provides a sensor area array based on flexible insulating material isolation and a preparation method thereof, and particularly relates to a method for preparing a curved surface palpation probe or a spherical palpation probe.

Description

Flexible sensor array, palpation probe and preparation method thereof

[ technical field ] A method for producing a semiconductor device

The invention belongs to the field of medical instruments, and particularly relates to a flexible sensor array-based constructed palpation probe and an implementation method thereof.

[ background of the invention ]

Chinese breast cancer has the tendency of high incidence rate, high mortality rate, high treatment difficulty and early onset age, but compared with other tumors, the early diagnosis and early treatment effect of breast cancer is better, and if the carcinoma in situ can be cured by nearly 100 percent. The main methods for examining breast cancer include clinical palpation, molybdenum target X-ray, ultrasound, nuclear magnetism, and breast endoscopy, all of which have certain limitations. The breast palpation imaging technology was proposed in the last 90 th century, and the corresponding medical instrument products appeared in 2003, which have the characteristics of high sensitivity, convenient operation, easy result interpretation and complete non-invasive property. Therefore, breast palpation imaging is a technique with great market prospect and social value.

The quality of the palpation probe is the key of the breast palpation imaging, the probe consists of an array of a plurality of longitudinal and transverse pressure sensors, after the probe presses the surface of a breast, the pressure sensors in the array can output different pressure signals due to different elastic moduli of corresponding tissues, and an instrument calculates the pressure signals to obtain the information of the hardness, the size, the shape and the like of a tumor so as to assist clinical diagnosis.

The traditional pressure sensor array structure mainly comprises an upper polar plate, a lower polar plate and elastic silica gel, wherein the silica gel is an insulating dielectric medium of a capacitor, and the elastic property of the silica gel is utilized to enable the sensor to make polar distance change corresponding to external force, so that the capacitor is changed. This approach has the following disadvantages: due to the manufacturing process, different sensors in the array have poor consistency and are sensitive to temperature, and silica gel cannot rebound or has insufficient rebound after long-time use.

It has been found through studies of the prior art that silicon-based capacitive sensors based on MEMS technology can solve the above problems. Through retrieval, many technical schemes related to a silicon-based capacitive sensor array based on an MEMS (micro electro mechanical System) process are disclosed in the prior art, but for how to adopt the MEMS array to manufacture a curved probe, the disclosed information is less how to solve the packaging problem in the scene. The basic strategies of the above schemes are: firstly, manufacturing a sensor linear array, and then manufacturing a curved surface sensor array based on reasonable packaging of the linear array, wherein the solving ideas are relatively simple and easy, but the following defects also exist: how to fill and level up gaps among the linear arrays to ensure that the end surfaces of the whole probe are flat is a problem which is difficult to solve, and on the other hand, the linear arrays are singly bonded on a flexible plate, so that the bonding heights are difficult to ensure to be completely consistent, and the difficulty of the flatness of the end surfaces of the probe is further increased; and the linear arrays are bonded one by one, so that the production efficiency is reduced, and the reliability is also reduced.

Thus, it is necessary to study how to more efficiently manufacture a highly reliable curved palpation probe.

[ summary of the invention ]

In order to solve the problems, the invention provides a curved surface palpation probe based on an MEMS wafer process and a preparation method thereof, and the specific technical scheme is as follows:

a method for preparing a flexible sensor array is characterized by comprising the following steps:

selecting a first silicon wafer, wherein the first surface of the first silicon wafer comprises a silicon dioxide layer;

etching the silicon dioxide layer to form a cavity array;

etching gaps of the cavity array to form criss-cross deep grooves, wherein the depth of the deep grooves exceeds the thickness of the silicon dioxide layer;

filling a flexible insulating material in the deep groove;

selecting an SOI (silicon on insulator) silicon chip, wherein the SOI silicon chip comprises an upper silicon chip, an insulating layer and a lower silicon chip, and bonding the surface of the lower silicon chip of the SOI silicon chip with the first surface of the first silicon chip;

removing the upper silicon wafer and the insulating layer of the SOI silicon wafer;

manufacturing a first electrode pattern on the surface of a lower silicon wafer of the SOI silicon wafer;

patterning a lower silicon wafer of the SOI silicon wafer according to the first electrode pattern, wherein the patterned lower silicon wafer has the same pattern as the first electrode;

thinning a second surface of the first silicon wafer, which is opposite to the first surface, until the elastic insulating material is exposed;

preparing a second electrode on the second surface of the first silicon wafer, wherein the second electrode corresponds to the cavity array to form a second electrode array;

and cutting the first silicon wafer to obtain the sensor array.

The invention also provides another preparation method of the flexible sensor array, which is characterized by comprising the following steps of:

etching the silicon dioxide layer to form a cavity array;

depositing a conductive material layer on the surface of the lower silicon wafer of the SOI silicon wafer;

etching a lower silicon wafer of the SOI silicon wafer to form criss-cross deep trenches, wherein the deep trenches are used for spacing the cavity array, and the conductive material layer is synchronously etched into a first electrode pattern;

filling a flexible insulating material in the deep groove;

and cutting the first silicon wafer to obtain the sensor array.

Preferably, the depth of the cavity does not exceed the thickness of the silicon dioxide layer.

Preferably wherein the resilient insulating material comprises PDMS.

Preferably, the deep trench has a depth exceeding the sum of the thicknesses of the lower silicon wafer and the silicon dioxide layer.

Preferably, the method further comprises covering the elastic insulating material on the surface of the conductive material layer.

The invention also provides a preparation method of the curved surface palpation probe, which is characterized by comprising the following steps: the method comprises the following steps:

manufacturing a flexible sensor array, wherein the flexible sensor array is manufactured according to the method provided by the invention;

manufacturing a flexible circuit board, wherein an electrode pad is arranged on the flexible circuit board;

packaging the flexible sensor array to the flexible circuit board, and establishing conductive connection between the flexible sensor array and the flexible circuit board;

bonding the flexible circuit board to a curved backing;

and carrying out surface insulation and shielding treatment on the flexible sensor array.

Preferably, the electrode pads on the flexible circuit board include a first electrode pad array and a second electrode pad array, which are respectively connected with the first electrode and the second electrode of the flexible sensor array in a conductive manner.

Preferably, the method further comprises the step of establishing electrical connection of the electrode pad with the collection cable.

Preferably, the method further comprises the step of carrying out surface flattening treatment on the flexible sensor array.

Preferably, the method also comprises the step of connecting the acquisition card and the host.

Preferably, the curved surface palpation probe is a spherical surface palpation probe.

The invention has the beneficial effects that: the invention provides a sensor area array isolated based on a flexible insulating material and a preparation method thereof.

[ description of the drawings ]

FIG. 1 is an exploded view of a sensor array in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a bottom electrode of a sensor array in an embodiment of the invention;

FIG. 3 is a schematic plan view of a sensor array in an embodiment of the invention;

FIG. 4 is a schematic diagram of an electrode pad of a flexible circuit board according to an embodiment of the present invention;

FIG. 5 is a schematic view of a curved probe according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a method for manufacturing a flexible sensor according to embodiment 1 of the present invention;

fig. 7 is a schematic view of a method for manufacturing a flexible sensor according to embodiment 3 of the present invention.

[ detailed description ] embodiments

The invention will now be described in further detail by way of the following detailed description with reference to fig. 1 to 7, in order to better understand the solution of the invention and its advantages in various aspects. In the following examples, the following specific embodiments are provided to facilitate a more thorough understanding of the present disclosure, and are not intended to limit the invention. Words and phrases indicating orientation, upper, lower, left, right, etc., herein, are used solely with respect to the illustrated structure as positioned within the corresponding figure.

Referring to fig. 1-5, the present invention provides a flexible sensor array unit, the sensor array structure includes an upper electrode 1, an elastic membrane (silicon) 2, a cavity array 3, a first silicon dioxide layer 4, an elastic insulation spacer layer 5, and a substrate layer 7, and referring to fig. 1:

the first silicon dioxide layer 4 and the second silicon dioxide layer 6 are made of the same layer of material, only the first silicon dioxide layer 4 is located in the sensor array unit, an array area is formed through etching, and the cavity array 3 can be prepared on the array area.

The second silicon dioxide layer 6 is positioned on the substrate layer 7, the second silicon dioxide layer 6 is etched to form a device area, the cavity array 3 is formed in the first silicon dioxide layer 4, the depth of the cavity is smaller than the thickness of the silicon dioxide layer, and the thickness part of the silicon dioxide layer which is excessive is used as an insulating layer of the capacitive sensor unit. The elastic insulating spacing layer 5 is positioned in the transverse and longitudinal grooves of the substrate layer 7 and the first silicon dioxide layer 4, so that on one hand, the effect of insulation is achieved, and on the other hand, the substrate layer and the silicon dioxide layer can be ensured to bend for a certain angle around a single axial direction. The elastic insulating spacer layer 5 is coplanar with the silicon dioxide layer 6 and the substrate layer 7, respectively, and they are tightly connected together. The elastic film layer 2 is arranged on the silicon dioxide layer 6, the elastic film is made of silicon, the elastic film layer 2 and the silicon dioxide layer 6 are attached together through similar processes such as direct bonding, and the elastic film 2 is of a strip-shaped structure. An upper electrode layer 1 is arranged above the elastic film 2, the upper electrode layer 1 and the elastic film layer 2 are closely attached together through processes of evaporation, magnetron sputtering and the like, the upper electrode 1 and the elastic film 2 are of strip-shaped structures, and the elastic film 2 and the upper electrode 1 of the strip-shaped structures can be formed through a graphical etching process. The strip-like structures form one row of the sensor array, shown as three rows in fig. 1 (of course, a row is also referred to as a row, i.e., three rows and four rows are shown). Each functional unit is composed of a plurality of cavities, the following schematic diagram shows four cavities, each cavity, an upper electrode area and a lower electrode area corresponding to the cavity constitute a capacitive sensor structural unit, a plurality of structural units constitute a sensor functional unit, one functional unit can be formed by connecting a plurality of structural units in parallel, and the following schematic diagram shows that four structural units constitute one functional unit.

Referring to fig. 2, the lower electrodes 8 of each functional unit, i.e., the unit of the cavity array 3, are isolated from each other, and there are 12 lower electrodes 8 in a total of 3 rows and 4 columns.

The sensor array is constructed by at least four sensor functional units of two rows and two columns, but preferably 12 rows and 16 columns, and 5 rows and 8 columns are selected, and the definitions of the rows and the columns can be exchanged, namely 16 rows and 12 columns are still the same as 12 rows and 16 columns in the preferred scheme. The size of each functional unit is preferably 2MM x 2MM, the functional units, the number of cavities of each functional unit is preferably 8 x 8, i.e. 64 cavities constitute one functional unit cavity part. The cavity depth is preferably 0.5 microns and the silica layer thickness is preferably 0.8 microns. The diameter of the cavity is preferably 100 microns. The thickness of the elastic film is preferably 2 micrometers, and the thickness of the upper electrode and the lower electrode is preferably 0.1 micrometer.

The curved surface probe is directly manufactured by the sensor area array, wherein the lead logic of the probe is as follows:

the upper electrodes 9 of each row are interconnected together, the lower electrodes 10 of each column are connected together, and the intersection point of the rows and the columns is a pressure sensor functional unit of the area array. As shown in fig. 3: there are 64 pressure sensor functional units.

Fig. 4 shows a flexible circuit board for use with an area array of MEMS pressure sensors, where four rows and five columns of electrode pads are formed on the flexible circuit board 11 in fig. 4, and the lower electrode pads 13 are connected together in each row. The isolated lower electrodes are interconnected by the lower electrode pads 13 which are connected together, and the lower electrodes and the lower electrode pads can be directly adhered together by using conductive adhesive or similar conductive substances. The area array itself interconnects the upper electrodes together and is connected to the flexible circuit board 11 through the corresponding upper electrode pads 12 in turn. The elastic insulation part between the strip-shaped upper electrodes 12 in the same direction as the upper electrodes can ensure that the sensor area array is conveniently lined and shaped on the cambered surface.

Further, the flexible circuit board 11, which is well connected to the sensor area array including the sensor function unit 14 and the elastic insulating portion 15, is integrally bonded to the arc surface by a liner. The upper and lower electrode lead wires and the probe cable are sequentially connected in sequence, as shown in fig. 5. And (3) manufacturing an insulating layer, a shielding layer and a leveling layer on the end face of the sensor area array at one time to obtain the palpation probe constructed based on the flexible sensor array. The insulating layer, the shielding layer and the planarization layer may be selected according to the conventional techniques in the art.

The clinical breast palpation imaging examination process comprises the steps of coating a couplant on the end surface of a palpation probe, pressing the palpation probe on the surface of a breast, slowly pressing the palpation probe, and then sliding the palpation probe to perform full-breast scanning so as to perform primary screening on whether a tumor exists. When a lump is found to exist, an image of the lump needs to be acquired. The acquisition mode is that the probe is continuously and slowly stressed until the image is very clear, and then the probe is required to be swung to all directions so as to observe the characteristics of the lump, such as shape, mobility and the like from different angles. Current palpation probes often use a cylindrical structure with a single axial arc that allows the operator to swing more easily in one particular direction, but swings in other directions are affected by the shape of the probe tip. The above problems can be solved if the probe end face is made into a spherical shape. However, how to manufacture the probe with the spherical sensor array end face becomes a technical problem which needs to be solved urgently in the field.

Based on the technical scheme, the problem can be solved, the flexible sensor area array is provided with a transverse elastic insulating part and a longitudinal elastic insulating part which penetrate through the whole area array, the sensor area array can be bent in a small range in any direction, and the flexible sensor array is wound on the spherical flexible circuit board and the spherical lining. In the flexible sensor area array, the lower electrodes are isolated and not connected with each other, and the upper electrodes are also isolated and not connected with each other. The spherical flexible circuit board is provided with lower electrode pads which are isolated from each other, when the spherical probe is manufactured, the isolated lower electrodes are sequentially electrically connected with the corresponding lower electrode pads, and the isolated lower electrodes can be connected in a conventional mode such as conductive adhesive; the upper electrodes are interconnected with each other. The spherical probe has the characteristics of sharing an upper electrode and separating all lower electrodes. It is easily conceivable that the spherical ultrasonic probe and other devices can be manufactured by using the scheme.

Example 1

The invention provides a preparation method of a flexible sensor array, which specifically comprises the following steps:

s100: selecting a suitable first substrate silicon wafer 16; the silicon substrate is, for example, 6 inches thick and 500 μm, and a silicon dioxide layer 17 having a thickness of about 1 μm is formed by thermal oxidation or deposition. It is also possible to directly select a silicon wafer with a 1 μm thick silicon dioxide layer, which is a heavily doped silicon wafer with a high conductivity, as shown in fig. 6a/6 b.

S101, patterning the silicon dioxide layer to form a cavity array 18 with the diameter of 50-100 mu m and the depth of 0.5 mu m; specifically, the patterning process may include cleaning, pre-baking, glue coating, post-baking, photolithography, developing, silicon dioxide etching, and photoresist removing processes, as shown in fig. 6 c.

S102, etching to form grooves of the interval cavity array; in order to space the cavity arrays, deep trenches 19 arranged in the transverse direction and the longitudinal direction can be etched between the cavity arrays, for example, the trench width is 0.5mm, the trench depth is 250, the trench width is 0.5mm, and the trench depth is 250 μm. The etching of the trench may be performed by wet etching or dry etching, or by mechanical scribing process with a controlled depth, or by laser with a controllable depth, as shown in fig. 6 d.

S103, filling the groove 19 with an elastic insulating material 20; the elastic insulating material is, for example, a high temperature resistant elastic insulating material, such as PDMS material, which ensures that the elastic insulating material establishes a good adhesion with the surrounding silicon material. During filling, a dispenser can be used to fill the transverse and longitudinal grooves, and the filling height should be slightly less than the depth of the grooves, so as not to affect direct silicon bonding in the subsequent process, as shown in fig. 6 e.

S104, selecting an SOI silicon wafer 21 and bonding the SOI silicon wafer with a first substrate silicon wafer; the SOI wafer 21 is silicon-bonded over the face of the first substrate wafer on which the array of cavities is formed, as shown in fig. 6 f.

S105, thinning the back of the SOI silicon wafer; specifically, the silicon layer on the back side opposite to the bonding surface of the bonded SOI silicon wafer 21 is removed by using, for example, TMAH solution, as shown in fig. 6g, and the buried oxide layer of the SOI silicon wafer is further removed by using BOE solution, as shown in fig. 6 h.

S106, depositing and patterning the conductive material 22 on the surface of the thinned SOI silicon wafer; for example, metal Al with a thickness of 0.1 μm is deposited, and further through the processes of gumming, photolithography, development and etching, a patterned upper electrode is formed, as shown in fig. 6i/6 j.

In this step, the patterned upper electrode may be a strip structure, and several array units have continuous upper electrodes; the upper electrode may also be patterned as a discrete upper electrode unit, i.e. the upper electrode of each array unit is isolated.

S107, patterning the rest part of the SOI silicon wafer: the patterned SOI silicon wafer has the same pattern as the upper electrode, namely the SOI silicon wafer of the area without the upper electrode is removed. The purpose is to avoid the problem that the reliability of the area array is affected by the fracture phenomenon possibly generated by the bending of the SOI silicon chip along with the elastic insulating material when the sensor area array is bent, as shown in FIG. 6 k.

S108: thinning the first substrate silicon wafer; and thinning the first substrate silicon wafer by adopting a thinning process until the elastic insulating material leaks out, and preferably thinning the first substrate silicon wafer until the silicon surface is slightly lower than the elastic insulating material part for ensuring the reliable insulating effect of the elastic insulating material, as shown in fig. 6 l.

S109: preparing a lower electrode, which is correspondingly covered in the cavity array region, for example, the range of the magnetron sputtering region can be limited by the hollow-out region of the mask plate, so as to form an isolated lower electrode array 23, as shown in fig. 6 n; of course, it is also possible to form the electrode layer first, as shown in fig. 6m, and then pattern the electrode layer to form the lower electrode, as shown in fig. 6 n.

And S110, cutting the sensor area array, namely cutting the wafer into the area array, such as a 4 x 3 sensor area array, wherein the area array can be bent at a certain angle around a single axial direction because of the strip-shaped elastic insulating material, so that preparation is made for manufacturing a curved probe. Of course, if no bending is performed, a planar probe can be made.

Spherical probes can also be prepared if the upper electrode elements are also discrete electrodes corresponding to the array of cavities.

Example 2

The invention provides a preparation method of a curved surface probe, which further comprises the following steps after the preparation of a flexible sensor area array is completed:

and S111, manufacturing a flexible circuit board, wherein the positions of the pads on the circuit board are consistent with the positions of the pads of the upper electrode and the lower electrode of the linear array of the sensor.

And S112, packaging the linear array of the sensor, smearing conductive adhesive at the position of a lower bonding pad of the flexible circuit board, and then placing the area array of the sensor at a corresponding position to ensure that the lower electrodes of the area array of the sensor are all in stable electrical connection with the corresponding bonding pads on the flexible circuit board. Or after the sensor bonding pad is used for ball planting, the sensor linear array and the flexible circuit board can be connected in a reflow soldering mode. The upper electrode can be connected with the flexible circuit board by locally coating conductive adhesive.

And S113, adhering the flexible circuit board of the welding sensor with the curved backing, and simultaneously establishing electrical connection between the upper electrode and the lower electrode and the acquisition cable. And (3) manufacturing an insulating layer, a shielding layer and a leveling layer on the end face of the sensor area array at one time to obtain the palpation probe constructed based on the flexible sensor array.

And S114, the palpation probe can be connected with the acquisition card system and the host computer to execute palpation imaging operation.

Example 3:

referring to fig. 7, the present invention further provides another method for manufacturing a flexible sensor array, which specifically includes the following steps:

s200: selecting a suitable first substrate silicon wafer 16; the silicon substrate is, for example, 6 inches thick and 500 μm, and a silicon dioxide layer 17 having a thickness of about 1 μm is formed by thermal oxidation or deposition. It is also possible to directly select a silicon wafer with a 1 μm thick silicon dioxide layer, which is a heavily doped silicon wafer with a higher conductivity, see fig. 7a/7 b.

S201, patterning the silicon dioxide layer to form a cavity 18 array with the diameter of 50-100 mu m and the depth of 0.5 mu m; specifically, the patterning process may include cleaning, pre-baking, glue coating, post-baking, photolithography, developing, silicon dioxide etching, and photoresist removing processes, as shown in fig. 7 c.

S203, selecting the SOI silicon wafer 21 and bonding the SOI silicon wafer with the first substrate silicon wafer 16; the SOI silicon wafer 21 covers the surface of the first substrate silicon wafer on which the cavity 18 array is formed to carry out silicon-silicon bonding; the SOI wafer comprises an upper silicon wafer, an insulating layer and a lower silicon wafer, and the surface of the lower silicon wafer of the SOI wafer is bonded to the first surface of the first silicon wafer 16, as shown in fig. 7 d.

S204, thinning the back of the SOI silicon wafer 21; specifically, for example, TMAH solution is used to remove the silicon layer on the back surface of the bonded SOI wafer opposite to the bonding surface, i.e., the upper silicon wafer, and BOE solution is used to remove the insulating layer of the SOI wafer, as shown in fig. 7e/7 f.

S205, depositing a conductive material 22 on the surface of the thinned SOI silicon wafer; for example, metallic Al is deposited to a thickness of 0.1 μm, see FIG. 7 g.

S206, etching the surface of the SOI lower silicon wafer with the surface electrode to form a groove 19 of a spacing cavity array; in order to space the cavity arrays, deep grooves arranged in the transverse direction and the longitudinal direction can be etched between the cavity arrays, for example, the groove width is 0.5mm, the groove depth is 250, the deep grooves are arranged in the transverse direction and the longitudinal direction, namely, the groove width is 0.5mm, and the groove depth is 250 μm. The etching of the groove can be realized by wet etching or dry etching, or by a mechanical scribing process with a certain depth controlled, or by a depth-controllable laser and the like.

In this embodiment, the deep grooves of the crisscross between the surface upper electrode and the cavity array unit are etched in the same pattern, thereby forming an isolated upper electrode corresponding to the cavity array unit.

S207, filling the elastic insulating material 20 in the groove; the elastic insulating material is, for example, an elastic insulating material resistant to high temperature, such as PDMS material, and can ensure that the elastic insulating material and the surrounding silicon material establish good adhesion. The filling of the lateral and longitudinal grooves can be performed by spraying or spin coating, and a PDMS layer is also formed on the upper electrode, see fig. 7 i.

And S208, thinning the back of the first substrate silicon wafer 16, for example, thinning the first substrate silicon by adopting a CMP (chemical mechanical polishing) process until the elastic insulating material leaks out, wherein the thinning target is that the silicon surface is slightly lower than the elastic insulating part for the reliability of the insulating effect of the elastic insulating material, and the step (see fig. 7 j) is included.

S209, preparing a lower electrode 23, wherein the lower electrode correspondingly covers the cavity array area, and the area range of magnetron sputtering can be limited through the hollow area of the mask plate, so that an isolated lower electrode array is formed, and the isolated lower electrode array is shown in figure 7k/7 l.

And S210, cutting the sensor area array, namely cutting the wafer into the area array, such as a 4 x 4 sensor area array, wherein the area array can be bent at a certain angle around the spherical surface direction because the area array has strip-shaped elastic insulating materials in the transverse direction and the longitudinal direction, so that preparation is made for manufacturing the spherical probe. Of course, if no bending is performed, a planar probe can be made. The probe can also be bent around a single axial direction, so that the cambered surface probe can be manufactured. The probe can also be bent around any direction and angle, so that the probe with a complex surface shape can be prepared for the palpation examination of a special scene.

Example 4:

the invention provides a preparation method of a spherical probe, which is similar to the method for manufacturing the curved probe in the embodiment 2, but the sensor matrix in the embodiment 3 is used, and the upper electrode and the lower electrode of the sensor matrix in the embodiment 3 are both isolated matrix electrodes, so that the sensor matrix is easy to bend. Such as: and the lower electrodes of the area array can be transversely and electrically connected by matching with a proper flexible circuit board. And then the flexible circuit board is laid on the front surface of the sensor, so that the upper electrodes of the area array can be longitudinally and electrically connected.

According to the sensor array preparation method and the curved surface probe or the spherical surface probe prepared by the sensor array, the method has the following remarkable advantages:

1. the probe packaging process has no bonding wire, and the following two adverse effects can be avoided: 1) the probe reliability caused by the breakage of the bonding wire is reduced, and 2) the existence of the bonding wire does not need to worry about the uneven pits on the outer surface of the sensor linear array when the upper end of the sensor linear array is coated with the silica gel protective film.

2. The probe has a compact structure, adopts mature processes common in the field, and has simple manufacturing process and high reliability.

3. The area array can be directly pasted on the flexible circuit board arranged on the curved backing without manufacturing the linear array and the sensor unit firstly, thereby reducing the process steps for manufacturing the probe, and improving the production efficiency and the reliability of the probe

4. Based on the technical scheme, the flexible sensor array can be bent around any direction and angle, so that the probe with a complex surface shape is prepared and used for the palpation examination of a special scene. For example, for palpation of the thyroid gland through complex cervical surfaces. For example, the breast palpation can be performed by a full-scale examination in which the breast palpation is performed at a time by making the breast palpation into a shape similar to the outer surface of the breast and fitting the breast palpation into the inner surface of the brassiere. Further, it is contemplated that by attaching a flexible sensor array to a balloon or sac, the sensor array may change as the balloon changes, which in turn may change adaptively as the surface being inspected changes. Therefore, it can be said that the proposed technical solution will increase the clinical application range of palpation imaging.

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

Claims

1. A method for preparing a flexible sensor array is characterized by comprising the following steps:

etching the silicon dioxide layer to form a cavity array;

filling a flexible insulating material in the deep groove;

and cutting the first silicon wafer to obtain the sensor array.

2. A method for preparing a flexible sensor array is characterized by comprising the following steps:

etching the silicon dioxide layer to form a cavity array;

etching a lower silicon wafer of the SOI silicon wafer to form criss-cross deep grooves which are spaced from the cavity array, wherein the conductive material layer is synchronously etched into a first electrode pattern;

filling a flexible insulating material in the deep groove;

and cutting the first silicon wafer to obtain the sensor array.

3. The method of manufacturing a flexible sensor array according to claim 1, wherein the first electrode is an isolated electrode array corresponding to the cavity array.

4. The method of manufacturing a flexible sensor array according to claim 1 or 2, wherein the depth of the cavity does not exceed the thickness of the silicon dioxide layer.

5. The method of claim 1 or 2, wherein the elastic insulating material comprises PDMS.

6. The method of claim 2, wherein the deep trench has a depth exceeding the sum of the thicknesses of the lower silicon wafer and the silicon dioxide layer.

7. The method of claim 2, further comprising covering the surface of the conductive material layer with the elastic insulating material.

8. A preparation method of the curved surface palpation probe is characterized in that: the method comprises the following steps:

fabricating a flexible sensor array, wherein the fabricating the flexible sensor array is performed according to the method of any one of claims 1-7;

bonding the flexible circuit board to a curved backing;

9. The method for preparing a curved palpation probe according to claim 8, wherein: the electrode pads on the flexible circuit board comprise a first electrode pad array and a second electrode pad array which are respectively in conductive connection with the first electrode and the second electrode of the flexible sensor array.

10. The method for preparing the curved palpation probe according to claim 8 or 9, wherein: further comprising the step of establishing an electrical connection of the electrode pad with a collection cable.

11. The method for preparing the curved palpation probe according to claim 8 or 9, wherein: the method also comprises the step of carrying out surface flattening treatment on the flexible sensor array.

12. The method for preparing the curved palpation probe according to claim 8 or 9, wherein: also comprises the step of connecting the acquisition card and the host.

13. The method for preparing a curved palpation probe according to claim 8, wherein: the curved surface palpation probe is a spherical surface palpation probe.