Abstract:
Provided is a stretchable devices. The stretchable device includes a first stretchable substrate having a first wavy surface that wrinkles in a first direction; first wiring lines extending along the first wavy surface in the first direction; a second stretchable substrate having a second wavy surface that faces the first wavy surface and wrinkles in a second direction intersecting the first direction, wherein the second stretchable substrate is disposed on the first stretchable substrate; second wiring lines extending along the second wavy surface in the second direction; and interlayer insulating layers disposed on the intersections of the first wiring lines and the second wiring lines and disposed between the first wiring lines and the second wiring lines.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This U.S. non-provisional patent application claims priority under 35 U.S.C. §119 of Korean Patent Application No. 10-2013-0154752, filed on Dec. 12, 2013, the entire contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention disclosed herein relates to an electronic device and a manufacturing method thereof, and more particularly, to a stretchable device and a manufacturing method thereof. 
         [0003]    Recently, research and development in a stretchable device that may maintain an electric function even though a substrate is expanded by external stress are actively performed. 
         [0004]    A stretchable electronic circuit has applicability to various fields, such as sensor skin for a robot, a wearable communication device, a bio-device built in or attached to a human body, and a next-generation display beyond the limit of a typical flexible device that is simply bendable. 
         [0005]    A shape of an electronic device may be deformed by using a stretchable substrate that may be bent or folded at will. A general stretchable device may include a wiring line which has a structure having high stretch. For example, the wiring line may be formed by the contraction of the stretchable substrate after being transferred to the surface of an inflated stretchable substrate. The wiring line may buckle into the surface of the stretchable substrate. 
         [0006]    However, the expandability of a general stretchable device is limited by the amount of strain applied initially to a substrate, and it may be difficult to fold or extent the general stretchable device to have a desired form and in a desired direction. Also, the reliability in operation of general stretchable device may decrease because electronic device regions in addition to the wiring line also experience deformation as the deformation of a substrate increases. 
         [0007]    Also, since a typical stretchable device has wiring lines extending in one direction, there may be a limitation in that it is vulnerable to strain provided in two directions. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention provides a stretchable device stretchable in two directions, and a manufacturing method thereof. 
         [0009]    The present invention also provides a stretchable device that may enhance reliability in operation, and a manufacturing method thereof. 
         [0010]    Embodiments of the inventive concept provide stretchable devices including a first stretchable substrate having a first wavy surface that wrinkles in a first direction; first wiring lines extending along the first wavy surface in the first direction; a second stretchable substrate having a second wavy surface that faces the first wavy surface and wrinkles in a second direction intersecting the first direction, wherein the second stretchable substrate is disposed on the first stretchable substrate; second wiring lines extending along the second wavy surface in the second direction; and interlayer insulating layers disposed on the intersections of the first wiring lines and the second wiring lines and disposed between the first wiring lines and the second wiring lines. 
         [0011]    In some embodiments, the first stretchable substrate may include a first wrinkled region on which the first wavy surface is formed, and first device regions corresponding to the intersections. 
         [0012]    In other embodiments, the stretchable device may further include electronic devices disposed between the interlayer insulating layer on the first device regions and the first wiring lines. 
         [0013]    In still other embodiments, the electronic devices may include semiconductor devices or a light source device. 
         [0014]    In even other embodiments, the stretchable device of claim  3  may further include lower insulating layers formed between the first wiring lines and the first stretchable substrate of the first device regions. 
         [0015]    In yet other embodiments, the lower insulating layers may have a vessel shape that surrounds the electronic devices and the interlayer insulating layer. 
         [0016]    In further embodiments, the lower insulating layers may include a silicon oxide layer or a silicon nitride layer. 
         [0017]    In still further embodiments, the second stretchable substrate may include a second wrinkled region on which the second wavy surface is formed, and second device regions corresponding to the intersections. 
         [0018]    In even further embodiments, the second device regions may include an interconnection planarization surface. 
         [0019]    In yet further embodiments, the first device regions and the second device regions may have the same shape. 
         [0020]    In much further embodiments, the stretchable device may further include third wiring lines that are parallel to the second wiring lines and extending along the second wavy surface in the second direction. 
         [0021]    In still much further embodiments, the stretchable device may further include fourth wiring lines that are parallel to the first wiring lines and extending along the first wavy surface in the first direction. 
         [0022]    In even much further embodiments, each of the first stretchable substrate and the second stretchable device may include polydimethylsiloxane (PDMS). 
         [0023]    In other embodiments of the inventive concept, methods of manufacturing a stretchable device include forming a first wavy surface wrinkling in a first direction on a first wrinkled region of a first stretchable substrate, first wiring lines extending along the first wavy surface in the first direction, and interlayer insulating layers on some of the first wiring lines; forming a second wavy surface wrinkling in a second direction intersecting the first direction on a lower surface of a second substrate facing the first stretchable substrate, and second wiring lines extending along the second wavy surface in the second direction; and bonding the first stretchable substrate to the second stretchable substrate           enable the first wiring lines and the second wiring lines to intersect on and under the interlayer insulating layer. 
         [0024]    In some embodiments, the forming of the first wavy surface, the first wiring lines and the interlayer insulating layers may include: providing a first mold substrate that has a first wavy mold surface wrinkling in a first direction and first planar mold surfaces formed on the first wavy mold surface in the shape of islands; forming the interlayer insulating layers on the first planar mold surfaces; forming the first wiring lines extending in the first direction on the interlayer insulating layers and the first wavy mold surface; forming the first stretchable substrate on the first wiring lines, the interlayer insulating layers and the first wavy mold surface; and removing the first mold substrate. 
         [0025]    In other embodiments, the method may further include: forming a first sacrificial layer between the first planar mold surfaces and the interlayer insulating layers; and removing the first sacrificial layer when removing the first mold substrate. 
         [0026]    In still other embodiments, the method may further include forming electronic devices between the first wiring lines and the interlayer insulating layers. 
         [0027]    In even other embodiments, the method may further include forming a lower insulating layer between the first wiring lines and the first stretchable substrate. 
         [0028]    In yet other embodiments, the forming of the second wavy surface and the second wiring lines may include: providing a second mold substrate that has a second wavy mold surface wrinkling in a second direction, and second planar mold surfaces formed on the second wavy mold surface in the shape of islands; forming second wiring lines extending in the second direction on the second wavy mold surface and the second planar mold surfaces; forming the second stretchable substrate on the second wiring lines and the second mold substrate; and removing the second mold substrate. 
         [0029]    In further embodiments, the method may further include: forming a second sacrificial on the second wavy mold surface and the second planar mold surfaces after providing the second mold substrate; and removing the second sacrificial layer when removing the second mold substrate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain principles of the present invention. In the drawings: 
           [0031]      FIG. 1  is a circuit diagram for explaining a stretchable device according to an embodiment of the inventive concept; 
           [0032]      FIG. 2  is a plane view of  FIG. 1 ; 
           [0033]      FIG. 3  is a cross-sectional view taken along a data line of  FIG. 2 ; 
           [0034]      FIG. 4  is a cross-sectional view taken along a gate line of  FIG. 2 ; 
           [0035]      FIG. 5  is a plane view of a stretchable device according to an application of the present invention; 
           [0036]      FIG. 6  is a cross-sectional view taken along power supply lines of  FIG. 5 ; 
           [0037]      FIGS. 7 to 19  are process, cross-sectional views of a method of manufacturing a stretchable device according to an embodiment of the inventive concept based on  FIG. 3 . 
           [0038]      FIG. 20  is a plane view of a lower stretchable substrate of  FIG. 14 ; and 
           [0039]      FIG. 21  is a plane view of an upper stretchable substrate of  FIG. 19 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0040]    Exemplary embodiments of the inventive concept are described below in more detail with reference to the accompanying drawings. The effects and features of the present invention, and implementation methods thereof will be clarified through following embodiments described with reference to the accompanying drawings. However, the present invention is not limited embodiments to be described below but may be implemented in other forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art, and furthermore, the present invention is only defined by scopes of claims. The same reference numerals throughout the disclosure refer to the same components. 
         [0041]    The terms used herein are only for explaining embodiments while not limiting the present invention. The terms of a singular form may include plural forms unless referred to the contrary. The terms used herein “includes”, “comprises”, “including” and/or “comprising” do not exclude the presence or addition of one or more components, steps, operations and/or elements other than the components, steps, operations and/or elements that are mentioned. Furthermore, since the following description presents an exemplary embodiment, the reference numerals presented according to the order of the description is not limited thereto. 
         [0042]      FIG. 1  is a circuit diagram for explaining a stretchable device according to an embodiment of the inventive concept.  FIG. 2  is a plane view of  FIG. 1 .  FIG. 3  is a cross-sectional view taken along data lines  20  of  FIG. 2 .  FIG. 4  is a cross-sectional view taken along a gate line  50  of  FIG. 2 . 
         [0043]    Referring to  FIGS. 1 to 4 , the stretchable device according to an embodiment of the inventive concept may include a lower stretchable substrate  10 , data lines  20 , electronic devices  30 , an interlayer insulating layer  40 , gate lines  50 , power supply lines  60 , and an upper stretchable substrate  70 . 
         [0044]    The lower stretchable substrate  10  may include first wrinkled regions  14  and first device regions  16 . The first wrinkled region  14  is a region where a first wavy surface  12  is formed on the upper surface of the lower stretchable substrate  10 . The first wavy surface  12  may wrinkle in a first direction. The first device regions  16  are regions where electronic devices  30  are formed. The first device regions  16  may be disposed in the first wrinkled regions  14  in the shape of islands. For example, the first device regions  16  may be rectangles. However, the present embodiment is not limited thereto. The first device regions  16  may be various shapes such as circles, triangles, or pentagons. The lower stretchable substrate  10  may include polydimethylsiloxane (PDMS). 
         [0045]    The data lines  20  may be disposed on the first wavy surface  12 . The data lines  20  may be extending in a first direction. The data lines  20  may be bent upwardly and downwardly along the first wavy surface  12 . 
         [0046]    The data lines  20  may contract or inflate in a first direction along the lower stretchable substrate  10 . For example, the data lines  20  may include a metal such as platinum (Au), silver (Ag), copper (Cu), aluminum (Al), tungsten (W), molybdenum (Mo), nickel (Ni), or cobalt (Co). 
         [0047]    The electronic devices  30  may be disposed on the first device regions  16 . The electronic devices  30  may be disposed on the intersections of the data lines  20  and the gate lines  50 . The electronic devices  30  may include a semiconductor device  32  and a light source device  33 . The semiconductor device  32  may include an addressing transistor  34 , a power transistor  36 , and a capacitor  38 . The light source device  33  may include an organic light-emitting device. 
         [0048]    The lower insulating layers  22  may be disposed between the electronic devices  30  and the lower stretchable substrate  10 . The lower insulating layers  22  may have a vessel shape that surrounds the data lines  20  of the first device regions  16  and the electronic devices  30 . The lower insulating layers  22  may include a silicon oxide layer or a silicon nitride layer. 
         [0049]    The interlayer insulating layer  40  may be disposed on the electronic devices  30 . The electronic devices  30  may be insulated from the gate lines  50  by the interlayer insulating layer  40 . The interlayer insulating layer  40  may provide a device planarization surface  42  of the loser stretchable substrate  10 . The interlayer insulating layer  40  and the lower insulating layers  22  may surround some of the data lines  20  and the electronic devices  30 . The present invention is not limited thereto and various variations may be implemented. For example, the gate lines  50  and the power supply lines  60  may also be electrically connected to the electronic devices  30  through the contact hole (not shown) of the interlayer insulating layer  40 . 
         [0050]    The upper stretchable substrate  70  may be disposed on the lower stretchable substrate  10 . The upper stretchable substrate  70  may include second wrinkled regions  74  and second device regions  76 . The second wrinkled region  74  is a region where a second wavy surface  72  is formed on the lower surface of the upper stretchable substrate  70 . The second wavy surface  72  may wrinkle in a second direction. The first direction and the second direction may intersect. The second device regions  76  are regions where the gate lines  50  are in contact with the interlayer insulating layer  40 . The second device regions  76  may be disposed in the second wrinkled regions  74  in the shape of islands. The second device regions  76  may have interconnection planarization surfaces  78 . The first device regions  16  may be aligned with the second device regions  76 . According to an example, the first device regions  16  and the second device regions  76  may have the same shape. For example, the second device regions  76  may be rectangles. The present embodiment is not limited thereto. The second device regions  76  may be various shapes such as circles, triangles, or pentagons. The upper stretchable substrate  70  and the lower stretchable substrate  10  may contract or inflate in two directions by an external force. 
         [0051]    The gate lines  50  may be disposed under the second wavy surface  72  and the interconnection planarization surface  78 . The gate lines  50  may be extending in a second direction. The gate lines  50  may be bent upwardly and downwardly along the second wavy surface  72 . The gate lines  50  may contract or inflate in the second direction along the upper stretchable substrate  70 . The gate lines  50  may be connected to the electronic devices  30 . When the upper stretchable substrate  70  contacts or inflates in the first direction, damage to the gate lines  50  may be minimized. Likewise, when the lower stretchable substrate  10  contacts or inflates in the second direction, damage to the data lines  50  may be minimized. 
         [0052]    The first device regions  16  and the second device regions  76  may correspond to the intersections of the first device regions  16  and the second device regions  76 . The gate lines  50  and the data lines  20  may define sub pixels. 
         [0053]    The power supply lines  50  may be parallel to the gate lines  50 . The power supply lines  60  may be extending in a second direction. The power supply lines  60  may be disposed under the second wavy surface  72  and the interconnection planarization surface  78  although not shown. The power supply lines  60  may be bent upwardly and downwardly along the second wavy surface  72 . The power supply lines  60  may be connected to the electronic devices  30  under the interconnection planarization surface  78 . The power supply lines  60  may contract or inflate in the second direction along the upper stretchable substrate  70 . 
         [0054]    The lower stretchable substrate  10  and the upper stretchable substrate  70  may contract or inflate in two directions by an external force. Likewise, the data lines  20  and the gate lines  50  may contract or inflate in two directions. The data lines  20  and the gate lines  50  may not be disconnected. 
         [0055]    Thus, the stretchable device according to an embodiment of the inventive concept may enhance reliability in operation. 
         [0056]      FIG. 5  is a plane view of a stretchable device according to an application of the present invention.  FIG. 6  is a cross-sectional view taken along data lines  60  of  FIG. 5 . 
         [0057]    Referring to  FIGS. 5 and 6 , the stretchable device according to an application of the present invention may include power supply lines  60  parallel to the data lines  20 . The power supply lines  60  may be extending in a first direction. The data lines  60  may be disposed on the first wavy surface  12 . The power supply lines  60  may be bent upwardly and downwardly along the second wavy surface  12 . The power supply lines  60  in the first device regions  16  may be disposed between the lower insulating layers and the electronic devices  30 . The application shows that the power supply lines  60  of the embodiment are parallel to the data lines  20 . 
         [0058]    A method of manufacturing the stretchable device according to the embodiment of the inventive concept having such a configuration is as follows. 
         [0059]      FIGS. 7 to 19  are process, cross-sectional views of a method of manufacturing a stretchable device according to an embodiment of the inventive concept based on  FIG. 3 .  FIG. 20  is a plane view of the lower stretchable substrate  10  of  FIG. 14 .  FIG. 21  is a plane view of the upper stretchable substrate of  FIG. 19 . 
         [0060]    Referring to  FIG. 7 , a first mold substrate  102  is provided. The first mold substrate  102  may include a silicon wafer. The first mold substrate  102  may have first wavy mold surfaces  101  and first planar mold surfaces  103 . The first wavy surface  101  may wrinkle in a first direction. The first planar mold surfaces  103  may be formed in the first wavy mold surfaces  101  in the shape of islands. The first wavy mold surfaces  101  and the first planar mold surfaces  103  may be formed by a photolithography process and an etching process. The etching process may be performed by wet etching. 
         [0061]    Referring to  FIG. 8 , a sacrificial layer  104  is formed on the first mold substrate  102 . The first sacrificial layer  104  may include a dielectric layer such as a silicon oxide layer or a silicon nitride layer. The dielectric layer may be formed by chemical vapor deposition (CVD) Also, the first sacrificial layer  104  may include an organic material such as resist or a polymer. 
         [0062]    The organic material may be formed by spin coating or by a sol-gel process. 
         [0063]    Referring to  FIG. 9 , the interlayer insulating layer  40  is formed on the first planar mold surface  103 . The interlayer insulating layer  40  may include a silicon oxide layer or a silicon nitride layer. When the interlayer insulating layer  40  and the first sacrificial layer  104  are formed of a silicon oxide layer, the first sacrificial layer  104  may include a TEOS silicon oxide layer having low density and the interlayer insulating layer  40  may include a HDCVD silicon layer having relatively high density. 
         [0064]    Referring to  FIG. 10 , the electronic devices  30  are formed on the interlayer insulating layer  40 . The electronic devices  30  may be bonded onto the interlayer insulating layer  40 . Also, the electronic devices  30  may be formed by unit processes. The unit processes may include a semiconductor layer deposition process, a photolithography process and an etching process. 
         [0065]    Referring to  FIG. 11 , the data lines  20  are provided on the electronic devices  30  and the first mold substrate  102 . The data lines  20  may be connected to the electronic devices  30 . The data lines  20  may be extending in a first direction. The data lines  20  may be formed to be bent upwardly and downwardly along the first wavy surface  101 . 
         [0066]    Referring to  FIG. 12 , the lower insulating layers  22  are formed which surround some of the data lines  20  and the electronic devices  30 . The lower insulating layers  22  may include a silicon oxide layer or a silicon nitride layer. The lower insulating layers may be formed by CVD, the photolithography process and the etching process. 
         [0067]    Referring to  FIG. 13 , the lower stretchable substrate  10  is formed as a whole on the first mold substrate  102 . The lower stretchable substrate  10  may include PDMS. The lower stretchable substrate  10  may be formed by spin coating or printing. 
         [0068]    Referring to  FIGS. 14 and 20 , the first mold substrate  102  and the first sacrificial layer  104  are removed. The first mold substrate  102  and the first sacrificial layer  104  may be removed by the etching process. The etching process may be performed by wet etching or dry etching. The data lines  20  may be extending on the lower stretchable substrate  10  in a first direction. 
         [0069]    Referring to  FIG. 15 , a second mold substrate  112  is provided. The second mold substrate  112  may include a silicon wafer. The second mold substrate  112  may have second wavy mold surfaces  111  and second planar mold surfaces  113 . The second wavy surface  111  may wrinkle in a second direction. The second planar mold surfaces  113  may be formed in the second wavy mold surfaces  111  in the shape of islands. The second wavy mold surfaces  111  and the second planar mold surfaces  113  may be formed by a photolithography process and an etching process. 
         [0070]    Referring to  FIG. 16 , a second sacrificial layer  114  is formed on the second mold substrate  112 . The second sacrificial layer  114  may include an inorganic layer such as a silicon oxide layer or a silicon nitride layer. The second sacrificial layer  114  may include an organic material such as resist or a polymer. 
         [0071]    Referring to  FIGS. 2 and 17 , the gate lines  50  and the power supply lines  60  are formed on the second sacrificial layer  114 . The gate lines  50  and the power supply lines  60  may be formed in a second direction along the second wavy mold surface  111  and the second planar mold surface  113 . The gate lines  50  and the power supply lines  60  may be formed by a metal deposition process, a photolithography process, and an etching process. The power supply lines  60  may be disposed on the same layer as the gate lines  50  although not shown in  FIG. 17 . 
         [0072]    Referring to  FIG. 18 , the upper stretchable substrate  70  is formed as a whole on the second mold substrate  112 . The upper stretchable substrate  70  may include PDMS. The upper stretchable substrate  70  may be formed by spin coating or printing. 
         [0073]    Referring to  FIGS. 19 and 21 , the second mold substrate  112  and the second sacrificial layer  114  are removed. The second mold substrate  112  and the second sacrificial layer  114  may be removed by an etching process. The etching process may be performed by wet etching or dry etching. The gate lines  50  and the power supply lines  60  may be extending on the upper stretchable substrate  70  in a second direction. 
         [0074]    Referring to  FIGS. 1 and 3 , the lower stretchable substrate  10  is bonded to the upper stretchable substrate  70 . Bonding of the lower stretchable substrate  10  and the upper stretchable substrate  70  may be include a mechanical bonding process. The first device regions  16  may be aligned with the second device regions  76 . The lower stretchable substrate  10  and the upper stretchable substrate  70  may be bonded by adhesive although not shown. 
         [0075]    As described above, the stretchable device according to embodiments of the inventive concept may include the lower stretchable substrate, the data lines, the interlayer insulating layer, the gate lines, and the upper stretchable substrate. The lower stretchable substrate may have the first wavy surface in a first direction. The data line may be extending along the first wavy surface in the first direction. The upper stretchable substrate may have the second wavy surface in a second direction. The gate line may be extending along the second wavy surface in the second direction. The lower stretchable substrate and the upper stretchable substrate may be combined in a direction in which the data line and the gate line intersect. The data line and the gate line may be insulated by the interlayer insulating layer. The lower stretchable substrate and the upper stretchable substrate may be stretched in two directions by an external force. Likewise, the data line and the gate line may be stretched in two directions. The data line and the gate line may not be disconnected. 
         [0076]    Thus, the stretchable device according to embodiments of the inventive concept may enhance reliability in operation. 
         [0077]    While embodiments of the inventive concept are described with reference to the accompanying drawings, a person skilled in the art will be able to understand that the present invention may be practiced as other particular forms without changing essential characteristics. Therefore, embodiments described above should be understood as illustrative and not limitative in every aspect.