Patent Publication Number: US-2023163059-A1

Title: Manufacturing method of metal grid, thin film sensor and manufacturing method of thin film sensor

Description:
TECHNICAL FIELD 
     The present disclosure relates to a technical field of electronic devices, and particularly relates to a manufacturing method of a metal grid, a thin film sensor and a manufacturing method of the thin film sensor. 
     BACKGROUND 
     At present, a line width in a micro-nano processing technology commonly used in glass-based semiconductor industry is about 2 to 3 µm. Some thin film display and sensing devices, such as a transparent antenna or a radio frequency device, put forward higher requirements on the line width in the micro-nano processing technology. The transparent antenna mainly uses a metal grid with a narrow line width as a signal transmitting and receiving unit, while the radio frequency device applies a narrower channel to achieve a higher cut-off frequency. 
     SUMMARY 
     The present invention aims to solve at least one technical problem in the related art, and provides a manufacturing method of a metal grid, a thin film sensor and a manufacturing method thereof. 
     In a first aspect, an embodiment of the present disclosure provides a manufacturing method of a metal grid, including:
     providing a base substrate;   forming a pattern including a first dielectric layer on the base substrate through a patterning process, such that the first dielectric layer has a first groove in a lattice shape;   forming a second dielectric layer on a side of the first dielectric layer away from the base substrate, such that the second dielectric layer is deposited at least on a sidewall of the first groove to form a second groove in a lattice shape; and   forming a metal material in the second groove, and removing at least a part of a material of the second dielectric layer such that an orthographic projection of the part of the material of the second dielectric layer on the base substrate does not overlap with an orthographic projection of the metal material on the base substrate, to form a metal grid.   

     The forming a pattern including a first dielectric layer on the base substrate through a patterning process includes: 
     forming a first material layer and a second material layer on the base substrate sequentially;   patterning the second material layer to form a sacrificial layer having a lattice-shaped hollow out pattern;   removing a part of a first material of the first material layer at a position corresponding to the lattice-shaped hollow out pattern of the sacrificial layer through a patterning process; and   removing the sacrificial layer to form the first dielectric layer.   

     The first material layer includes a low-temperature organic curing adhesive; the forming a first material layer and a second material layer on the base substrate includes:
     coating the low-temperature organic curing adhesive on the base substrate by a spin coating method, and curing the low-temperature organic curing adhesive; and   depositing a second material of the second material layer on a side of the cured low-temperature organic curing adhesive away from the base substrate.   

     The forming a metal material in the second groove includes: 
     forming a metal film layer as a seed layer on a side of the second dielectric layer away from the base substrate;   performing an electroplating process on the seed layer to form a metal material both in the second groove and on a side of the second dielectric layer away from the base substrate; and   removing at least a part of the metal material outside the second groove.   

     The removing at least a part of the metal material outside the second groove includes: 
     removing the part of the metal material outside the second groove, and removing a part of the metal material with a predetermined thickness in the second groove. 
     The forming a metal material in the second groove includes:
     forming a metal film layer on a side of the second dielectric layer away from the base substrate, through an evaporation process; and   removing at least a part of the metal material outside the second groove by an etching process.   

     The forming a metal material in the second groove includes: 
     forming a metal film layer on the base substrate as a seed layer before the step of forming a pattern including a first dielectric layer on the base substrate through a patterning process;   forming a protective layer on a side of the seed layer away from the base substrate;   after the forming a second dielectric layer on a side of the first dielectric layer away from the base substrate, removing a bottom wall of the second groove and a part of the protective layer at a position of the bottom wall of the second groove; and   performing an electroplating process on the seed layer to form the metal material in the second groove.   

     The removing at least a part of a material of the second dielectric layer such that an orthographic projection of the part of the material of the second dielectric layer on the base substrate does not overlap with an orthographic projection of the metal material on the base substrate includes: 
     removing a part of the second dielectric layer such that an orthographic projection of the part of the material of the second dielectric layer on the base substrate does not overlap with an orthographic projection of the metal material on the base substrate, by wet etching; and   removing the first dielectric layer by dry etching.   

     After forming the metal grid, the manufacturing method in an embodiment of according to the present disclosure further includes: 
     forming a passivation layer on a side of the metal grid away from the base substrate. The first dielectric layer has a thickness of 2 µm to 3 µm. 
     The first groove in the first dielectric layer has a width of 3 µm to 4 µm and a depth of 2 µm to 3 µm. 
     A width of the second groove is not greater than 1.5 µm. 
     In a second aspect, an embodiment of the present disclosure provides a manufacturing method of a thin film sensor, including the above manufacturing method of a metal grid. 
     In a third aspect, an embodiment of the present disclosure provides a thin film sensor, including: 
     a base substrate;   a second dielectric layer arranged on the base substrate;   a metal grid arranged on a side of the second dielectric layer away from the base substrate, wherein an orthographic projection of the metal grid on the base substrate is within an orthographic projection of the second dielectric layer on the base substrate.   

     A thickness of the metal grid is not less than a thickness of the first dielectric layer. 
     A line width of the metal grid is not greater than 2 µm. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a schematic diagram of a structure of a thin film sensor according to an embodiment of the present disclosure. 
         FIG.  2    is a cross-sectional view of a structure of the film sensor in  FIG.  1    taken along a line A-A′. 
         FIG.  3    illustrates a top view of an intermediate product formed in a step S2 of a manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  4    is a cross-sectional view of a structure of the intermediate product in  FIG.  3    taken along a line B-B′. 
         FIG.  5    illustrates a top view of an intermediate product formed in a step S3 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  6    is a cross-sectional view of a structure of the intermediate product in  FIG.  5    taken along a line C-C′. 
         FIG.  7    illustrates a top view of the metal grid formed in a step S4 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  8    is a cross-sectional view of a structure of the formed metal grid as shown in  FIG.  7    along a line D-D′. 
         FIG.  9    is a cross-sectional view of a structure of an intermediate product formed in a step S21 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  10    is a cross-sectional view of a structure of an intermediate product formed in a step S22 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  11    is a cross-sectional view of a structure of an intermediate product formed in a step S23 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  12    is a cross-sectional view of a structure of an intermediate product formed in a step S42 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  13    is a cross-sectional view of a structure of an intermediate product formed in a step S43 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  14    is a cross-sectional view of a structure of the intermediate product during forming the metal grid as shown in  FIG.  5    along a line C-C′. 
         FIG.  15    is a cross-sectional view of a structure of the intermediate product formed in the step S42 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  16    is a cross-sectional view of a structure of the intermediate product formed in the step S43 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  17    is a cross-sectional view of a structure of an intermediate product formed in a step S47 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  18    is a cross-sectional view of a structure of a metal grid formed by the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  19    is a cross-sectional view of a structure of an intermediate product formed in a step S04 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  20    is a cross-sectional view of a structure of an intermediate product formed in a step S05 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  21    is a cross-sectional view of a structure of an intermediate product formed in a step S06 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
         FIG.  22    is a cross-sectional view of a structure of an intermediate product formed in a step S07 of the manufacturing method of a metal grid according to an embodiment of the present disclosure. 
     
    
    
     DETAIL DESCRIPTION OF EMBODIMENTS 
     In order to make the technical solutions of the present disclosure better understood by those skilled in the art, the present disclosure is further described in detail below with reference to the accompanying drawings and specific embodiments. 
     Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of general skills in the art to which the present disclosure belongs. The words “first”, “second”, and the like used in the present disclosure are not intended to indicate any order, quantity, or importance, but rather are used to distinguish one element from another. Also, the word “a”, “an”, “the” or the like does not denote a quantity limitation, but rather denotes the presence of at least one. The word “comprising”, “including”, “includes”, “comprises”, or the like means that the element or item preceding the word includes the element or item listed after the word and its equivalent, but does not exclude other elements or items. The word “connected”, “coupled” or the like is not restricted to a physical or mechanical connection, but may include an electrical connection, whether direct or indirect. The words “upper”, “lower”, “left”, “right”, and the like are used only to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly. 
       FIG.  1    is a schematic diagram of a structure of an exemplary thin film sensor.  FIG.  2    is a cross-sectional view of the structure of the thin film sensor as shown in  FIG.  1    along a line A-A. As shown in  FIGS.  1  and  2   , the thin film sensor includes: a base substrate  100  having a first surface and a second surface, i.e., an upper surface and a lower surface, oppositely disposed; and a first conductive layer  101  and a second conductive layer  102  which are respectively located on the first surface and the second surface of the base substrate  100 . Taking the film sensor being a transparent antenna as an example, the first conductive layer  101  may be a radiation layer, and the second conductive layer  102  may be a ground layer. The radiation layer may be used as a receiving unit of an antenna structure, and may also be used as a transmitting unit of the antenna structure. 
     In order to ensure that the first conductive layer  101  and the second conductive layer  102  have good light transmittance, the first conductive layer  101  and the second conductive layer  102  need to be patterned. For example, the first conductive layer  101  may be formed by grid wires made of a metal material, and the second conductive layer  102  may also be formed by grid wires made of a metal material. It is understood that the first conductive layer  101  and the second conductive layer  102  may alternatively be formed by a structure of other patterns, for example, by block electrodes of diamond, triangle, etc., which are not listed herein. As can be seen from  FIG.  1   , the first conductive layer  101  and the second conductive layer  102 , i.e., the grid wires, are not entirely provided on both surfaces of the base substrate  100 . Any grid wire is formed by metal grids electrically connected with each other. Due to the material and the forming process of the metal grid, a line width of the metal grid is large, light transmittance of the film sensor is seriously influenced, and user’s experience is influenced. 
     It should be noted that the above metal grid is not limited to be applied in an antenna structure, and may alternatviely be applied in a touch panel to function as a touch electrode. Of course, the metal grid may alternatively be used in various applications using the metal wires, which are not listed herein. 
     In order to solve the above technical problem, a manufacturing method of a metal grid is provided in an embodiment of the present disclosure. In an embodiment of the present disclosure, the metal grid is only applied to an antenna as a receiving unit and/or a transmitting unit of the antenna, as an example, but it should be understood that this does not limit the scope of the embodiment of the present disclosure. 
       FIG.  3    illustrates a top view of an intermediate product formed in a step S2 of a manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  4    is a cross-sectional view of a structure of the intermediate product obtained during forming the metal grid as shown in  FIG.  3    along a line B-B′.  FIG.  5    illustrates a top view of an intermediate product formed in a step S3 of the manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  6    is a cross-sectional view of a structure of the intermediate product obtained during forming the metal grid as shown in  FIG.  5    along a line C-C′.  FIG.  7    illustrates a top view of the metal grid formed in a step S4 of the manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  8    is a cross-sectional view of a structure of the formed metal grid as shown in  FIG.  7    along a line D-D′. 
     In a first aspect, as shown in  FIGS.  3  to  8   , in an embodiment of the present disclosure, a manufacturing method of a metal grid  400  is provided, and includes the following steps: 
     S1, providing a base substrate  100 . 
     In some embodiments, the base substrate  100  may be a flexible film, and the flexible film may include at least one of a COP film, a Polyimide (PI) material, or a polyethylene terephthalate (PET) material. In such a case, in S1, the flexible COP film may be attached to a glass substrate through a transparent optical adhesive (OCA adhesive), and then the glass substrate on which the COP film is formed may be cleaned. 
     S2, forming a pattern including a first dielectric layer  200  on the base substrate  100  through a patterning process such that the first dielectric layer  200  has a first groove  201  in a lattice shape, and a width of the first groove  201  is a first width W1, as shown in  FIGS.  3  and  4   . 
     The first groove  201  may be a through slot penetrating through the first dielectric layer  200 , or may be a blind slot penetrating the first dielectric layer  200  by a certain thickness. In an embodiment of the present disclosure, the first groove  201  is described as the through slot as shown in  FIG.  3   , as an example. In some examples, the first dielectric layer  200  may be an organic curing adhesive that may be cured at a low temperature, and has a thickness of about 2.5 µm to about 3.5 µm. The width W1 of the first groove  201  in the first dielectric layer  200  is about 3 µm to 4 µm, and a corresponding depth is about 2 µm to 3 µm, and a specific depth of the first groove  201  depends on the thickness of the first dielectric layer  200 . Certainly, in an embodiment of the present disclosure, the first dielectric layer  200  is not limited to the organic curing adhesive, and may alternatively be made of an insulating dielectric layer material such as silicon oxide and silicon nitride. The reason that the organic curing adhesive is used as the material of the first dielectric layer  200  in an embodiment of the present disclosure is to ensure that a sidewall of the formed first groove  201  is perpendicular to a surface of the base substrate  100 , which faciliates a uniform line width of the metal grid  400  formed subsequently. 
     S3, a second dielectric layer  300  is formed on a side of the first dielectric layer  200  away from the base substrate  100 , and the second dielectric layer  300  is deposited at least on the sidewall of the first groove  201  to form a second groove  301  in a lattice shape, as shown in  FIGS.  5  and  6   . 
     As shown in  FIG.  6   , the second groove  301  is actually a blind slot defined by the second dielectric layer  300  deposited on the sidewall of the first groove  201 . A width of the second groove  301  is a second width W2, and obviously the second width W2 is smaller than the first width W1, and the second width W2 of the blind slot is determined by a thickness of the formed second dielectric layer  300 . In an embodiment of the present disclosure, the second dielectric layer  300  may be deposited only on the sidewall of the first groove  201 , or may be deposited not only on the sidewall of the first groove  201 , but also on the surface of the first dielectric layer  200  away from the base substrate  100 , that is, an orthographic projection of the second dielectric layer  300  on the base substrate  100  covers the base substrate  100 . In some examples, the second dielectric layer  300  is deposited to a thickness such that a groove width of the first groove  201  is reduced from 3-4 µm to less than 2.0 µm, i.e., the second width W2 of the second groove  301  formed by the second dielectric layer  300  is not greater than 1.5 µm. In some examples, the second dielectric layer  300  may be a single layer structure of a silicon oxide film or a silicon nitride film, or a composite film of a silicon oxide film and a silicon nitride film. 
     S4, forming a metal material in the second groove  301 , and removing a part of the first dielectric layer  200  and a part of the second dielectric layer  300  having an orthographic projection on the base substrate  100  not overlapping an orthographic projection of the metal material on the base substrate  100 , to obtain the metal grid  400 , as shown in  FIGS.  7  and  8   . 
     In some examples, the metal material includes, but is not limited to, one or more of copper, titanium, aluminum and silver. A line width of the metal grid  400  formed in an embodiment of the present disclosure is 1.5 µm or less, where the line width of the metal grid  400  refers to a width of a metal line formed of a metal material formed in the second groove  301 , and the width of the metal line is equal to or substantially equal to the second width of the second groove  301 . 
     The metal grid  400  is thus obtained. 
     In the manufacturing method in an embodiment of the present disclosure, the second dielectric layer  300  is deposited on the sidewall of the first groove  201  to reduce a width of the first groove  201 , that is, to form the second groove  301  (a width of the groove is changed from the first width W1 to the second width W2, W2 being smaller than W1), and then the metal material is formed in the second groove  301 . At this time, the line width of the formed metal grid  400  is narrower, and the metal grid  400  is applied to the thin film sensor, which is helpful for improving light transmittance of the product. 
     In some examples, the step S2 of the forming a pattern including the first dielectric layer  200  on the base substrate  100  such that the first dielectric layer  200  has the first groove  201  in a lattice shape may be specifically implemented as follows.  FIG.  9    is a cross-sectional view of a structure of an intermediate product formed in a step S21 of the manufacturing method of a metal grid  400  in an embodiment of the present disclosure.  FIG.  10    is a cross-sectional view of a structure of an intermediate product formed in a step S22 of a manufacturing method of a metal grid  400  in an embodiment of the present disclosure.  FIG.  11    is a cross-sectional view of structure of an intermediate product formed in a step S23 of the manufacturing method of a metal grid  400  in an embodiment of the present disclosure. 
     S21, forming a first material layer  20  and a second material layer  50  on the base substrate  100  sequentially, as shown in  FIG.  9   . 
     A material of the first material layer  20  includes, but is not limited to, a low temperature organic curing adhesive. A material of the second material layer  50  includes, but is not limited to, a transparent conductive metal, such as ITO (indium tin oxide). In an embodiment of the present disclosure, to be described as an example, the material of the first material layer  20  is the low temperature organic curing adhesive, and the material of the second material layer  50  is ITO. 
     Step S21 may specifically include: first, forming a low temperature organic curing adhesive with a thickness of about 2 µm to 3 µm on the base substrate  100  by a spin coating method, and curing the low temperature organic curing adhesive at 110° C. to 150° C., specifically, it may be 130° C. Next, an ITO material layer with a thickness of about 50 nm to 80 nm (e.g., 70 nm) is formed on a side of the low temperature organic curing adhesive away from the base substrate  100  by, but not limited to, a sputtering process. 
     S22, patterning the second material layer  50  to form a sacrificial layer  500  having a lattice-shaped hollow out pattern  501 , as shown in  FIG.  10   . 
     Step S22 may specifically include forming a photoresist on the second material layer  50 , that is, on a side of the ITO material layer away from the base substrate  100 , and then performing exposure, development, and etching processes to form the sacrificial layer  500  having the lattice-shaped hollow out pattern  501 . 
     S23, removing the material of the first material layer  20  at a position corresponding to the lattice-shaped hollow out pattern  501  of the sacrificial layer  500  through a patterning process, as shown in  FIG.  11   . 
     Step S23 may specifically include removing the low temperature organic curing adhesive (the material of the first material layer  20 ) at the position of the lattice-shaped hollow out pattern  501  by dry etching. 
     S24, removing the sacrificial layer  500  to form the first dielectric layer  200 , as shown in  FIGS.  3  and  4   . 
     Step S24 may specifically include removing the sacrificial layer  500  by wet etching, that is, removing the remaining ITO material, so as to form the first dielectric layer  200  having the first groove  201 . 
     In an embodiment of the present disclosure, the sacrificial layer  500  is used as a mask for forming the first groove  201 , so that damage to a side edge of the first groove  201  when the organic curing adhesive is etched can be effectively avoided, and the depth of the first groove  201  can be ensured. 
     In some examples, in the step S4, the forming a metal material in the second groove  301 , and removing a part of the first dielectric layer  200  and a part of the second dielectric layer  300  having an orthographic projection on the base substrate  100  not overlapping an orthographic projection of the metal material on the base substrate  100 , to obtain the metal grid  400  may specifically be implemented as follows. In this case, as an example, the formed metal grid  400  is a titanium/copper laminated structure.  FIG.  12    is a cross-sectional view of a structure of an intermediate product formed in a step S42 of a manufacturing method of a metal grid  400  in an embodiment of the present disclosure.  FIG.  13    is a cross-sectional view of a structure of an intermediate product formed in a step S43 of the manufacturing method of a metal grid  400  in an embodiment of the present disclosure. 
     S41, sequentially depositing a titanium film and a copper film on a side of the second dielectric layer  300  away from the base substrate  100  by a sputtering process, i.e. forming a metal film layer  40 . 
     It should be noted that only one copper film may be deposited in this step, and the titanium film is used to increase the adhesion of the copper film. 
     S42, performing an electroplating process with the metal film layer  40  as a seed layer, as shown in  FIG.  12   . 
     Step S42 specifically includes: placing the base substrate  100  on a carrier of an electroplating machine, with a side of the base substrate  100  having the second dielectric layer  300  facing the carrier; pressing a power-on pad on the second dielectric layer  300 ; placing the base substrate in a hole-filling electroplating bath (with a dedicated hole-filling electrolyte in the bath); applying a current such that the electroplating solution keeps flowing continuously and rapidly on the surface of the base substrate  100 , and cations in the electroplating solution on the sidewall of the second groove  301  obtain electrons to become atoms to be deposited on the sidewall. Through the dedicated hole-filling electrolyte with a special ratio, the metal copper may be deposited mainly in the second groove  301  at a high speed (deposition speed of 0.5 µm/min to 3 µm/min), while the deposition speed of the metal copper on the second dielectric layer  300  is quite low (0.005 µm/min to 0.05 µm/min). As time elapes, the metal copper on the sidewall of the second groove  301  gradually grows thick, and even the second groove  301  may be completely filled, and finally the base substrate  100  is taken out and subjected to deionized water cleaning. 
     S43, the metal material outside the second groove  301  is removed by a copper etching solution, as shown in  FIG.  13   . 
     Of course, in step S43, the metal material outside the second groove  301  may be removed by dry etching. 
     S44, removing a part of the second dielectric layer  300  having an orthographic projection on the base substrate  100  notoverlapping an orthographic projection of the metal material on the base substrate  100  by wet etching. 
     S45, removing the first dielectric layer  200  by dry etching, i.e. the metal grid  400  is formed, as shown in  FIGS.  8  and  9   . 
     In some embodiments,  FIG.  14    is a cross-sectional view of a structure of the intermediate product obtained during forming the metal grid as shown in  FIG.  5    along a line C-C′. As shown in  FIG.  14   , due to the process, a second dielectric layer  300  is formed on a side of the first dielectric layer  200  having the first groove  201  away from the base substrate  100 , a thickness of the second dielectric layer  300  deposited on the sidewall of the first groove  201  is not constant, and obviously in a direction away from the base substrate  100 , the thickness of the second dielectric layer  200  deposited on the sidewall of the first groove  201  becomes thinner gradually, so that the groove width of the formed second groove  301  is not uniform. As shown in  FIG.  14   , the width of the second groove  301  at an end away from the base substrate  100  is significantly greater than the width at an end close to the base substrate  100 . In this case, in some examples, the step S4 include not only the above-described steps S41-43 but also the following steps S46 and S47. Since the width of the second groove  301  at the end away from the base substrate  100  is significantly larger than the width at the end close to the base substrate  100 , in the electroplating process of the step S42, the metal material formed in the second groove  301  also has a width at the end away from the base substrate  100  that is significantly larger than the width at the end close to the base substrate  100 , as shown in  FIG.  15   . The structure formed in the step S43 is shown in  FIG.  17   . The following specifically describes steps S46 and S47. 
     S46, removing a part of the material of the second dielectric layer  300  on a side of the first dielectric layer  200  away from the base substrate  100  by wet etching or an ashing process. 
     S47, removing a part of the metal material with a predetermined thickness in the second groove  301  by using the copper etching solution, as shown in  FIG.  17   . 
     It should be noted that the predetermined thickness should be a difference between the thickness of the metal material formed in the second groove  301  in the step S42 and the thickness of the metal grid  400  to be formed. 
     In addition, the metal film layer  40  on the surfaces of the second groove  301  and the second dielectric layer  300  is formed on the second dielectric layer  300  through sputtering and plating processes as above. In some examples, the metal film layer  40  may alternatively be formed on the surfaces of the second groove  301  and the second dielectric layer  300  through an evaporation process. 
     In an embodiment of the present disclosure, after obtaining the metal grid  400 , the manufactuing method further includes forming a passivation layer  500  on a side of the metal grid  400  away from the base substrate to protect the metal grid  400 , so as to prevent the metal grid  400  from being corroded by water and oxygen. 
     An embodiment of the present disclosure further provides a manufacturing method of a metal grid.  FIG.  19    is a cross-sectional view of a structure of an intermediate product formed in a step S04 of the manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  20    is a cross-sectional view of a structure of an intermediate product formed in a step S05 of the manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  21    is a cross-sectional view of a structure of an intermediate product formed in a step S06 of the manufacturing method of a metal grid in an embodiment of the present disclosure.  FIG.  22    is a cross-sectional view of a structure of an intermediate product formed in a step S07 of the manufacturing method of a metal grid in an embodiment of the present disclosure. The manufatuing method includes the following steps: 
     S01, providing a base substrate  100 . 
     This step may be the same as the step S1 described above, and thus will not be described in detail herein. 
     S02, forming a metal film layer  40  and a protective layer on the base substrate  100  sequencely. 
     Forming the metal film layer  40  in the step S02 may include, but is not limited to, sputtering. The protective layer includes, but is not limited to, an organic dielectric layer. 
     S03, forming a first dielectric layer  200  on a side of the protective layer away from the base substrate  100 , wherein the first dielectric layer  200  has a first groove  201 . 
     The step S03 may include the steps S21-S24, and thus will not be described in detail herein. 
     S04, forming a second dielectric layer  300  on a side of the first dielectric layer  200  away from the base substrate  100  to form a second groove  301 , as shown in  FIG.  19   . 
     The step S04 may be the same as the step S3 of forming the second dielectric layer, and thus will not be described in detail herein. 
     S05, removing a bottom wall of the second groove  301  and a part of the protective layer corresponding to the bottom wall of the second groove  301 , as shown in  FIG.  20   . 
     In the step S05, the bottom wall of the second groove  301  and the part of the protection layer corresponding to the bottom wall of the second groove  301  may be removed by wet etching, so as to expose a part of the metal film layer  40  at a position of the second groove  301 . 
     S06, performing an electroplating process with the metal film layer  40  as a seed layer such that a metal material is formed in the second groove, as shown in  FIG.  21   . 
     The electroplating process in the step S06 is the same as the step S42, and therefore, will not be described in detail herein. 
     S07, removing the first dielectric layer  200 , the second dielectric layer  300 , the protective layer and a part of the metal film layer  40  except the metal material in the second groove  301  on the base substrate  100 , to form a metal grid  400 , as shown in  FIG.  22   . 
     Of course, after the metal grid  400  is formed, a passivation layer  500  may be further formed on a side of the metal grid  400  away from the base substrate  100  to protect the metal grid  400 , so as to prevent the metal grid  400  from being corroded by water and oxygen. 
     In a second aspect, an embodiment of the present disclosure further provides a manufacturing method of a thin film sensor, including, but not limited to, a transparent antenna, and the manufacturing method of the thin film sensor may include the above-described manufacturing method of the metal grid  400 . 
     Since the manufacturing method of the thin film sensor in an embodiment of the present disclosure includes the manufacturing method of the metal grid  400 , the light transmittance of the thin film sensor formed by this method is high, and the influence on the optical effect of the display device after the thin film sensor is applied to the display device is significantly reduced. 
     In a third aspect, an embodiment of the present disclosure further provides a thin film sensor, which may be manufactured using the above method. The thin film sensor includes, but is not limited to, a transparent antenna. The metal grid in the thin film sensor in an embodiment of the present disclosure is prepared by the above method, so the line width of the metal grid is not greater than 2 µm, for example, less than 1.5 µm. The thickness of the metal grid  400  in an embodiment of the present disclosure is not less than the thickness of the second dielectric layer  300 . 
     Referring to  FIG.  8   , the thin film sensor specifically includes a base substrate  100 , a second dielectric layer  300 , and a metal grid  400  on the second dielectric layer  300 . In this case, the metal grid  400  and the second dielectric layer  300  have the same pattern, and their orthographic projections on the base substrate  100  completely overlap with each other. It should be noted that, in an embodiment of the present disclosure, the up-down relationships of the formed structure are defined according to the sequence of depositing the film layers in the manufacturing method. For example, the deposition layer of the second dielectric layer  300  is formed before the metal grid  400 , so the metal grid is considered to be located on the second dielectric layer  300 . 
     Referring to  FIG.  13   , the thin film sensor specifically includes a base substrate  100 , a first dielectric layer  200  disposed on the base substrate  100 , a second dielectric layer  300  disposed on the first dielectric layer  200 , and a metal grid  400  located on the second dielectric layer  200 . In this case, the metal grid  400  is formed in the second groove  301  of the second dielectric layer  200 . In addition, an outer wall of the metal grid  400  is wrapped by the first dielectric layer  200  and the second dielectric layer  300 , so that the metal grid may be protected. 
     In some examples, as shown in  FIG.  18   , the thin film sensor further includes a passivation layer  500  covering a side of the metal grid  400  away from the base substrate to protect the metal grid  400 , so as to prevent the metal grid  400  from being corroded by water and oxygen. 
     It will be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present invention, and the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and improvements may be made without departing from the spirit and scope of the invention, and such modifications and improvements are also considered to be within the scope of the invention.