Patent Publication Number: US-2020281068-A1

Title: High-frequency electronic device and manufacturing method thereof

Description:
This application is a divisional application of co-pending application Ser. No. 15/858,004, filed at Dec. 29, 2017, which claims the benefit of U.S. provisional application Ser. No. 62/446,581, filed Jan. 16, 2017 and People&#39;s Republic of China application Serial No. 201710286875.6, filed Apr. 27, 2017, the subject matters of which are incorporated herein by references. 
    
    
     TECHNICAL FIELD 
     The disclosure relates in general to an electronic device, and more particularly to a high-frequency electronic device. 
     BACKGROUND 
     In recent years, the application of high-frequency electronic device has gained great popularity. However, due to the special features of high-frequency operation, how to reduce the manufacturing cost and at the same time reduce the decay of electromagnetic wave during the propagating process has become a prominent task for the industries. 
     SUMMARY 
     The disclosure is directed to a high-frequency electronic device. Through the design disclosed in the embodiments of the present disclosure, the dielectric substrate has a lower loss tangent in a first region corresponding to a first patterned metal layer, such that the decay rate of electromagnetic wave during the propagating process is smaller in the first region. 
     According to one embodiment of the present disclosure, a high-frequency electronic device is provided. The high-frequency electronic device includes a dielectric substrate, a first patterned metal layer and a second patterned metal layer. The dielectric substrate has a first side, a second side opposite to the first side, a first region, and a second region adjacent to the first region, wherein the first region and the second region have different etching rates with respect to an etching solution. The first patterned metal layer is disposed on the first side of the dielectric substrate and corresponds to the first region. The second patterned metal layer is disposed on the first side of the dielectric substrate or the second side. 
     According to another embodiment of the present disclosure, a manufacturing method of high-frequency electronic device is provided. The manufacturing method of high-frequency electronic device includes following steps: A dielectric substrate is provided. A laser is applied to a first region of the dielectric substrate but not a second region adjacent to the first region of the dielectric substrate, wherein the first region and the second region have different etching rates with respect to an etching solution. A first patterned metal layer is formed on a first side of the dielectric substrate and corresponds to the first region. A second patterned metal layer is formed on the first side or a second side opposite to the first side of the dielectric substrate. 
     The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment(s). The following description is made with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a high-frequency electronic device according to an embodiment of the present disclosure. 
         FIG. 1A  is a schematic diagram of a high-frequency electronic device according to another embodiment of the present disclosure. 
         FIG. 2  is a schematic diagram of a high-frequency electronic device according to of the present disclosure an alternate embodiment. 
         FIG. 3  is a schematic diagram of a high-frequency electronic device according to of the present disclosure another alternate embodiment. 
         FIG. 4A  is a 3D diagram of a high-frequency electronic device according to an embodiment of the present disclosure. 
         FIG. 4B  is a cross-sectional view of the high-frequency electronic device  FIG. 4A . 
         FIG. 4C - FIG. 4E  are cross-sectional view of a high-frequency electronic device according to some embodiments of the present disclosure. 
         FIG. 5A - FIG. 5D  are manufacturing processes of a manufacturing method of high-frequency electronic device according to an embodiment of the present disclosure. 
         FIGS. 6A - FIG. 6B  and  FIGS. 7A - FIG. 7B  are manufacturing processes of a manufacturing method of high-frequency electronic device according to some embodiments of the present disclosure. 
         FIGS. 8A-8G  are examples of a dielectric substrate manufactured using a manufacturing method according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     A number of embodiments of the present disclosure are disclosed below with reference to accompanying drawings. Reference numerals common to the accompanying drawings and embodiments are used to indicate identical or similar elements. It should be noted that the drawings are simplified such that the content of the embodiments can be clearly described. In addition, detailed structures disclosed in the embodiments are for explanatory and exemplary purposes only, not for limiting the scope of protection of the present disclosure. Although the present disclosure does not illustrate all possible embodiments, a person ordinary skilled in the technology field can make necessary modifications or adjustments to fit actual needs without breaching the spirit and scope of the present disclosure. 
       FIG. 1  is a schematic diagram of a high-frequency electronic device according to another embodiment of the present disclosure. As indicated in  FIG. 1 , the high-frequency electronic device  10  includes a dielectric substrate  100 , a first patterned metal layer  200  and a second patterned metal layer  300 . The dielectric substrate  100  has a first region  100 A, a second region  100 B adjacent to the first region  100 A, a first side S 1 , and a second side S 2  opposite to the first side S 1 . The first patterned metal layer  200  is disposed on the first side S 1  of the dielectric substrate  100  and corresponds to the first region  100 A. The second patterned metal layer  300  is disposed on the second side S 2  of the dielectric substrate  100 . The first region  100 A and the second region  100 B have different etching rates with respect to an etching solution. It should be noted that the high-frequency electronic device  10  can be realized by an antenna device such as a liquid crystal antenna or a circuit device capable of transmitting high-frequency signals. The frequency of the high-frequency signal is for example in a range from 1 to 50 GHz, but the present disclosure is not limited thereto. It should be noted that “disposed on” may refer to “indirectly disposed on” or “directly disposed on” if not particularly noted. In the present disclosure, the dielectric substrate  100  is an electrical insulator through which the electromagnetic wave passes during the propagating process. 
     As indicated in  FIG. 1 , a first projection P 1  of the first patterned metal layer  200  on the dielectric substrate  100  overlaps the first region  100 A, and the first projection P 1  does not overlap the second region  100 B. It should be noted than a projection of an object on a substrate refers to an orthogonal projection of the object on the substrate. It should be noted that “overlap” may refer to “partially overlap” or “completely overlap” if not particularly noted. 
     In some embodiments, the first region  100 A has a first etching rate with respect to an etching solution, the second region  100 B has a second etching rate with respect to the etching solution, and the first etching rate is smaller than the second etching rate. In some embodiments, the etching solution is an 8% HF solution. The first etching rate is 1-2 μm/min in an 8% HF solution. The second etching rate is 3-5 μm/min in an 8% HF solution. However, the present disclosure is not limited to the above range of the etching rate. 
     Based on the embodiments of the present disclosure, the first region  100 A of the dielectric substrate  100  having been processed with a suitable treatment (such as a laser treatment) has a higher crystallinity but a lower loss tangent, and the second region  100 B of the dielectric substrate  100  not having been processed with any suitable treatments has a lower crystallinity. The first region  100 A and the second region  100 B have different etching rates with respect to the etching solution because the first region  100 A and the second region  100 B have different degrees of crystallinity. The loss tangent, which can be denoted by tan δ, refers to the electric energy consumed by a dielectric substance and converting to heat energy per unit volume per unit time. The loss tangent is a physical quantity of the electric energy consumed by a dielectric substance having received an AC electric field. 
     In some embodiments, the first patterned metal layer  200  and the second patterned metal layer  300  can be realized by transmission lines. As indicated in  FIG. 1 , the dielectric substrate  100  has a lower loss tangent in the first region  100 A on which the first patterned metal layer  200  is disposed, such that the decay rate of electromagnetic wave during the propagating process is smaller in the first region  100 A and thus the first region  100 A is a suitable medium for high-frequency transmission. 
     In some embodiments as indicated in  FIG. 1 , a second projection P 2  of the second patterned metal layer  300  on the dielectric substrate  100  overlaps the second region  100 B. 
     In an embodiment as indicated in  FIG. 1 , the first pattered metal layer  200  and the second patterned metal layer  300  are disposed on two opposite sides of the dielectric substrate  100  and are separated by a first distance D 1 , wherein the first distance D 1  is the shortest distance between the first patterned metal layer  200  and the second patterned metal layer  300  along the normal direction of a surface of the dielectric substrate  100 . As indicated in  FIG. 1 , the second projection P 2  of the second pattered metal layer  300  can overlap the first region  100 A and the second region  100 B at the same time, and the electric field line EL indicates the distribution range of electric field induced by a voltage difference between the first patterned metal layer  200  and the second patterned metal layer  300 . 
     As indicated in  FIG. 1 , the second patterned metal layer  300  is disposed on the second side S 2  of the dielectric substrate  100  and is separated from the first patterned metal layer  200  by the first distance D 1 , and a lateral side of the first patterned metal layer  200  is separated from a lateral side of the first region  100 A by a second distance D 2 , wherein the second distance D 2  is the shortest distance between a lateral side of the first patterned metal layer  200  and a lateral side of the first region  100 A along a direction perpendicular to the normal direction of a surface of the dielectric substrate  100 . The second distance D 2  is, for example, 2 to 6 times the first distance D 1  or 2 to 6 times the width W of the first patterned metal layer  200 . In another embodiment, the second distance D 2  is, for example, 3 to 5 times the first distance D 1  or 3 to 5 times the width W of the first patterned metal layer  200 . In the embodiment as indicated in  FIG. 1 , the range of fringe field (the second distance D 2 ) is approximate 2 to 6 or 3 to 5 times the distance between the first patterned metal layer  200  and the second patterned metal layer  300  (the first distance D 1 ) or 2 to 6 or 3 to 5 times the width W of the first patterned metal layer  200 . 
     In some embodiments, the materials of the first patterned metal layer  200  and the second patterned metal layer  300  may include copper, silver, gold, palladium, molybdenum, titanium or indium zinc oxide (IZO), but the present disclosure is not limited thereto. 
     In some embodiments, the dielectric substrate  100  can be realized by a glass substrate including amorphous silicon oxide. After the first region  100 A is processed with a laser treatment, the first region  100 A has a higher crystallinity like the quartz, and therefore has a lower loss tangent. Meanwhile, the second region  100 B not having been processed with the laser treatment still remains the state of amorphous glass. Based on the embodiments of the present disclosure as indicated in  FIG. 1 , since the electromagnetic wave is propagating within the distribution range of electric field and the first region  100 A having a lower loss tangent substantially covers the distribution range of electric field, the first region  100 A is a suitable medium for high-frequency transmission. Moreover, the localized region in the dielectric substrate  100 , such as the first region  100 A, is processed with the crystallinity treatment for reducing loss tangent, so the manufacturing cost can be reduced. In this disclosure, the dielectric substrate  100  can be a rigid substrate which includes glass, ceramic or quartz. Or, the dielectric substrate  100  can be a flexible substrate which includes polyimide, polycarbonate, polyethylene terephthalate, or the like. The present disclosure it not limited thereto. 
     In some embodiments, the dielectric substrate  100  can be realized by such as a glass substrate, the etching solution can be realized by an alkaline etching solution includes such as sodium hydroxide, potassium hydroxide or a combination thereof, or an acidic etching solution includes such as hydrofluoric acid, nitric acid, hydrochloric acid, phosphoric acid, oxalic acid, acetic acid or a combination thereof, but the present disclosure is not limited thereto. 
       FIGS. 1A-4E  are schematic diagrams of a high-frequency electronic device according to some embodiments of the present disclosure. For elements the same as or similar to above embodiments, the same or similar reference numerals are used to indicate the same or similar elements, and the similarities are not repeated here. 
     In an embodiment of the high-frequency electronic device  10 A as indicated in  FIG. 1A , the second projection P 2  of the second patterned metal layer  300  on the dielectric substrate  100  overlaps the first region  100 A. 
     In some embodiments as indicated in  FIG. 1A , the first patterned metal layer  200 , the second patterned metal layer  300  and the dielectric substrate  100  can be realized by such as capacitors, the width W of the first patterned metal layer  200  is substantially equivalent to the width of the second patterned metal layer  300 , and the second projection P 2  of the second patterned metal layer  300  does not overlap the second region  100 B of the dielectric substrate  100 . 
       FIG. 2  is a schematic diagram of a high-frequency electronic device according to an alternate embodiment of the present disclosure, the high-frequency electronic device  20  further includes a substrate  400 , wherein the second patterned metal layer  300  is disposed on the first side S 1  of the dielectric substrate  100 . In other words, the second patterned metal layer  300  is disposed on a side of the substrate  400  which faces the first side S 1  of the dielectric substrate  100 . In an embodiment, the substrate  400  can be realized by such as a glass substrate. 
     In an embodiment as indicated in  FIG. 2 , the first patterned metal layer  200  is interposed between the second patterned metal layer  300  and the dielectric substrate  100  and is separated from the second patterned metal layer  300  by a first distance D 1 , wherein the first distance D 1  is the shortest distance between the first patterned metal layer  200  and the second patterned metal layer  300  along the normal direction of a surface of the dielectric substrate  100 . A lateral side of the first patterned metal layer  200  is separated from a lateral side of the first region  100 A by a second distance D 2 , wherein the second distance D 2  is the shortest distance between a lateral side of the first patterned metal layer  200  and a lateral side of the first region  100 A along a direction perpendicular to the normal direction of a surface of the dielectric substrate  100 , and the second distance D 2  is 2 to 6 or 3 to 5 times the first distance D 1  or 2 to 6 or 3 to 5 times the width W of the first patterned metal layer  200 . 
       FIG. 3  is a schematic diagram of a high-frequency electronic device according to of the present disclosure another alternate embodiment. The thickness T 1  of the first region  100 A of the dielectric substrate  100  is smaller than the thickness T 2  of the dielectric substrate  100 . In an embodiment, the thickness T 1  can be larger than or equal to 10 micrometers (μm). In some other embodiments of the high-frequency electronic device  10  as indicated in  FIG. 1 , the thickness T 1  of the first region  100 A of the dielectric substrate  100  is equal to the thickness T 2  of the dielectric substrate  100 . 
       FIG. 4A  is a 3D diagram of a high-frequency electronic device according to an embodiment of the present disclosure.  FIG. 4B  is a cross-sectional view of the high-frequency electronic device  FIG. 4A . As indicated in the high-frequency electronic device  40  of  FIGS. 4A-4B , the first patterned metal layer  200  and the second patterned metal layer  300  are co-planar (that is, the first patterned metal layer  200  and the second patterned metal layer  300  both are disposed on the first side S 1  of the dielectric substrate  100 ) and are separated by an interval S. In more details, the second patterned metal layer  300  comprises two separated parts, the first patterned metal layer  200  is disposed between the two separated parts, and a shortest distance between a lateral side of one separated part and a lateral side of the first patterned metal layer  200  along a direction perpendicular to the normal direction of a surface of the dielectric substrate is defined as the interval S. The first patterned metal layer  200  has a width W, and the first region  100 A of the dielectric substrate  100  has a width W 1 , wherein W 1  is in a range from 2W+2S to 13W+2S. In another embodiment, W 1  is in a range from 5W+2S to 11W+2S. 
     In some embodiments, the first patterned metal layer  200  and the second patterned metal layer  300  can be realized by such as coplanar waveguide, the distributions of magnetic field line H and electric field line EL are indicated in  FIG. 4B , and the coverage of the electric field line EL indicates the distribution of electric field. As indicated in  FIG. 4B , the dielectric substrate  100  has a lower loss tangent in the first region  100 A on which the first patterned metal layer  200  is disposed, such that the decay rate of electromagnetic wave during the propagating process is smaller in the first region  100 A and thus the first region  100 A is a suitable medium for high-frequency transmission. 
       FIGS. 4C-4E  are cross-sectional views of a high-frequency electronic device according to some embodiments of the present disclosure. In some embodiments, the cross-sectional shape of the first region  100 A of the dielectric substrate  100  can be a square or a trapezoid. As indicated in the high-frequency electronic device  40  of  FIG. 4A-4B , the cross-sectional shape of the first region  100 A is a square. 
     As indicated in the high-frequency electronic device  40 - 1  of  FIG. 4C , the first side S 1  (on which the first patterned metal layer  200  is disposed) faces upward, the cross-sectional shape of the first region  100 A of the dielectric substrate  100  can be a trapezoid, and the length of the bottom edge is smaller than the length of the top edge. 
     As indicated in the high-frequency electronic device  40 - 2  of  FIG. 4D , the first side S 1  (on which the first patterned metal layer  200  is disposed) faces upwards, the cross-sectional shape of the first region  100 A of the dielectric substrate  100  can be a trapezoid, and the length of the bottom edge is larger than the length of the top edge. 
     As indicated in the high-frequency electronic device  40 - 3  of  FIG. 4E , the first side S 1  (on which the first patterned metal layer  200  is disposed) faces upwards, and the cross-sectional shape of the first region  100 A of the dielectric substrate  100  is formed of two trapezoids. Of the trapezoid closer to the first side S 1 , the length of the bottom edge is smaller than the length of the top edge. Of the trapezoid farther away from the first side S 1 , the length of the bottom edge is larger than the length of the top edge. 
       FIGS. 5A-5D  are manufacturing processes of a manufacturing method of high-frequency electronic device according to an embodiment of the present disclosure. For elements the same as or similar to above embodiments, the same or similar reference numerals are used to indicate the same or similar elements, and the similarities are not repeated here. 
     As indicated in  FIG. 5A , a dielectric substrate  100  is provided. 
     As indicated in  FIG. 5B , a laser L is applied on a first region  100 A of the dielectric substrate  100  but not a second region  100 B adjacent to the first region  100 A. Since the first region  100 A has better crystallinity, the first region  100 A having been processed with a laser treatment and the second region  100 B not having been processed with a laser treatment have different etching rates with respect to an etching solution. 
     In some embodiments, the laser can be a continuous wave laser or a pulsed laser. 
     In an embodiment, the conditions of the continuous wave laser are illustrated in Table 1. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 Range of wavelength 
                 500-1200 
                 nanometers (nm) 
               
               
                   
                 Repetition rate 
                 200-500 
                 kHz 
               
               
                   
                 Pulse energy 
                 0.2-2.6 
                 pJ 
               
               
                   
                   
               
            
           
         
       
     
     In an embodiment, the conditions of the pulsed laser are illustrated in Table 2. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 2 
               
               
                   
                   
               
             
            
               
                   
                 Range of wavelength 
                 500-1200 
                 nanometers (nm) 
               
            
           
           
               
               
               
            
               
                   
                 Pulse duration 
                 nanosecond-femtosecond 
               
            
           
           
               
               
               
               
            
               
                   
                 Repetition rate 
                 200-500 
                 kHz 
               
               
                   
                 Pulse energy 
                 0.2-2.6 
                 μJ 
               
               
                   
                   
               
            
           
         
       
     
     In an embodiment as indicated in  FIG. 5B , the first region  100 A has a cross-sectional width of 50 nm-1 μm and a thickness of 250-500 μm, and the thickness of the first region  100 A is substantially equal to the thickness of the dielectric substrate  100 . As indicated in  FIG. 5B , two first regions  100 A are separated by approximately 100 μm. 
     As indicated in  FIG. 5C , the first region  100 A of the dielectric substrate  100  can be selectively processed with a heat treatment at a temperature of 600-800° C. by using a furnace  500  such as an electric furnace or a high-temperature furnace. The heat treatment can further increase the crystallinity of the first region  100 A. 
     According to other practice, the crystallization of the amorphous glass normally requires a heat treatment using a high-temperature furnace at a temperature above 1000° C. Based on the embodiments of the present disclosure, the laser treatment can increase crystallinity in a localized first region  100 A. When the crystallinity of the first region  100 A is selectively further increased by way of heat treatment, a heat treatment using a high-temperature furnace at a temperature of 600-800° C. would suffice to increase the crystallinity. Therefore, the manufacturing cost can be reduced and the manufacturing process can be simplified. 
     As indicated in  FIG. 5D , a first patterned metal layer  200  is formed on the first side S 1  of the dielectric substrate  100  and corresponds to the first region  100 A. In an embodiment as indicated in  FIG. 5D , the first patterned metal layer  200  can include copper and the width W of the first patterned metal layer  200  is equal to or smaller than the width of the first region  100 A of the dielectric substrate  100 . 
     Then, a second pattered metal layer  300  is formed on the first side S 1  or the second side S 2  of the dielectric substrate  100  with reference to the drawings of previous embodiments. 
       FIGS. 6A-6B  and  FIGS. 7A-7B  are manufacturing processes of a manufacturing method of high-frequency electronic device according to some embodiments of the present disclosure. For elements the same as or similar to above embodiments, the same or similar reference numerals are used to indicate the same or similar elements, and the similarities are not repeated here. 
     As indicated in  FIG. 6A - FIG. 6B , when the step of forming the first patterned metal layer  200  and/or the second patterned metal layer  300  is performed after the step of applying a laser L on the dielectric substrate  100 , the laser L can be applied to both sides of the dielectric substrate  100 . As indicated in  FIG. 6A - FIG. 6B , after the first region  100 A is formed, an element (such as the first pattered metal layer  200 ) is formed on the first region  100 A. 
     As indicated in  FIG. 7A - FIG. 7B , when the step of applying a laser L on the dielectric substrate  100  is performed after the step of forming an element (such as the first patterned metal layer  200  and/or the second patterned metal layer  300 ) is completed, the laser L needs to be applied to the side of the dielectric substrate  100  opposite to the side of the dielectric substrate  100  on which the element is formed. As indicated in  FIG. 7A - FIG. 7B , after an element (the first patterned metal layer  200 ) is formed on the dielectric substrate  100 , the first region  100 A is formed on a position corresponding to the first patterned metal layer  200 . 
       FIGS. 8A-8G  are examples of a dielectric substrate manufactured using a manufacturing method according to some embodiments of the present disclosure. For elements the same as or similar to above embodiments, the same or similar reference numerals are used to indicate the same or similar elements, and the similarities are not repeated here. 
     As indicated in  FIG. 8A - FIG. 8B , when the thickness T 1  of the first region  100 A of the dielectric substrate  100  is set to be equal to the thickness T 2  of the dielectric substrate  100  and the cross-sectional shape of the first region  100 A is set to be a square, during the formation of the first region  100 A, the laser L can be applied from either the first side S 1  or the second side S 2  of the dielectric substrate  100 . 
     As indicated in  FIG. 8C - FIG. 8D , when the thickness T 1  of the first region  100 A of the dielectric substrate  100  is set to be smaller than the thickness T 2  of the dielectric substrate  100  and the cross-sectional shape of the first region  100 A is set to be a square, during the formation of the first region  100 A, the laser L can be applied from either the first side S 1  or the second side S 2  of the dielectric substrate  100 . For example, a confocal laser is applied from the second side S 2  to form the first region  100 A. 
     As indicated in  FIG. 8E - FIG. 8F , when the thickness T 1  of the first region  100 A of the dielectric substrate  100  is set to be smaller than the thickness T 2  of the dielectric substrate  100  and the cross-sectional shape of the first region  100 A is a trapezoid, during the formation of the first region  100 A, the applying direction of the laser L is related to the shape of the trapezoid. 
     As indicated in  FIG. 8E , when the laser L is applied from the first side S 1  of the dielectric substrate  100 , the first side S 1  faces upwards, and the length of the bottom edge is smaller than the length of the top edge of the trapezoid. As indicated in  FIG. 8F , when the laser L is applied from the second side S 2  of the dielectric substrate  100 , the first side S 1  faces upwards, and the length of the bottom edge is larger than the length of the top edge of the trapezoid. As indicated in  FIG. 8G , when the laser L is applied from both the first side S 1  of the dielectric substrate  100  and the second side S 2  of the dielectric substrate  100 , the first side S 1  faces upwards, and the cross-sectional shape of the first region  100 A of the dielectric substrate  100  is formed of two trapezoids. Of the trapezoid closer to the first side S 1 , the length of the bottom edge is smaller than the length of the top edge. Of the trapezoid farther away from the first side S 1 , the length of the bottom edge is larger than the length of the top edge. 
     It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.