PATENT DOCUMENT

Publication Number: US-9911550-B2
Application Number: US-201313784749-A
Country: US
Kind Code: B2

Title: Touch sensitive device with multiple ablation fluence values

Abstract:
Processes for fabricating compact touch sensors for touch sensitive devices are disclosed. A process can include providing a touch sensor structure having a substrate, a first layer disposed on the substrate, and a second layer disposed on the first layer. The second layer can have an ablation fluence value that is lower than an ablation fluence value of the first layer. The process can include patterning the second layer with a laser emitting energy having a fluence value greater than or equal to the ablation fluence value of the second layer and less than the ablation fluence value of the first layer. The process can further include etching at least a portion of the first layer that was exposed during the patterning of the second layer. At least a portion of the second layer can then be removed by etching or laser ablation.

Claims:
What is claimed is: 
     
       1. A touch sensitive device comprising:
 a substrate; 
 a first layer disposed on the substrate, the first layer including first touch sensing lines and second touch sensing lines, the first layer having a first ablation fluence value; 
 a first area of the first layer including:
 the first touch sensing lines; and 
 
 a second area of the first layer located between outside the first area to outer edges of the substrate, the second area including:
 the second touch sensing lines, and 
 a second layer disposed on the second touch sensing lines, the second layer comprising a plurality of conductive routing traces and having a second ablation fluence value, the plurality of conductive routing traces coupled to the second touch sensing lines, 
 
 wherein the second ablation fluence value is less than the first ablation fluence value, 
 wherein a spacing between adjacent conductive routing traces in the second area oriented along a direction is less than a spacing between adjacent first touch sensing lines in the first area oriented along the direction, and 
 wherein a size and location of an entire pattern of the second touch sensing lines in all of the second area are same as a size and location of an entire pattern of the plurality of conductive routing traces in all of the second area. 
 
     
     
       2. The touch sensitive device of  claim 1 , wherein the second ablation fluence value is between 60-100 mJ/cm 2 . 
     
     
       3. The touch sensitive device of  claim 1 , wherein the first layer comprises indium tin oxide and the second layer comprises Ti. 
     
     
       4. The touch sensitive device of  claim 2 , wherein the first ablation fluence value is 2 J/cm 2 . 
     
     
       5. The touch sensitive device of  claim 1 , wherein the substrate is undamaged. 
     
     
       6. The touch sensitive device of  claim 1 , wherein the second layer is a combination of layers. 
     
     
       7. The touch sensitive device of  claim 1 , wherein the second layer includes a metal. 
     
     
       8. The touch sensitive device of  claim 1 , wherein the second layer functions as a mask for patterning the first layer. 
     
     
       9. The touch sensitive device of  claim 1 , wherein the second layer is excluded from the first area. 
     
     
       10. The touch sensitive device of  claim 1 , wherein a pattern of the first layer is different than a pattern of the second layer in the first area. 
     
     
       11. The touch sensitive device of  claim 1 , wherein the second layer is patterned to form:
 a plurality of rows; and 
 a plurality of strips along edges of the substrate that are connected to the plurality of rows. 
 
     
     
       12. The touch sensitive device of  claim 1 , further comprising:
 a third layer located in the first and a second areas and having a third ablation fluence value; and 
 a fourth layer located in the second area and having a fourth ablation fluence value. 
 
     
     
       13. The touch sensitive device of  claim 12 , wherein the third and fourth layers are disposed on the substrate opposite the first layer. 
     
     
       14. The touch sensitive device of  claim 12 , wherein the fourth layer is disposed on the third layer, and the third layer is disposed on the substrate. 
     
     
       15. The touch sensitive device of  claim 12 , wherein the fourth ablation fluence value is less than the third ablation fluence value. 
     
     
       16. The touch sensitive device of  claim 12 , wherein the fourth layer comprises indium tin oxide, and the third layer comprises Ti. 
     
     
       17. The touch sensitive device of  claim 12 , wherein the fourth ablation fluence value is 2J/cm 2 and the third ablation fluence value is between 60-100 mJ/cm 2 . 
     
     
       18. The touch sensitive device of  claim 12 , wherein a pattern of the third layer is same as a pattern of the fourth layer in the second area. 
     
     
       19. The touch sensitive device of  claim 12 , wherein the first layer is patterned to form a plurality of columns, and the third layer is patterned to form a plurality of rows that are at least substantially perpendicular to the plurality of columns. 
     
     
       20. The touch sensitive device of  claim 12 , wherein the fourth layer is a same material as the second layer. 
     
     
       21. The touch sensitive device of  claim 12 , wherein the fourth layer is a different material than the second layer. 
     
     
       22. The touch sensitive device of  claim 1 , wherein the first area is a viewable area, and the second area is a border area.

Description:
FIELD 
     This relates generally to touch sensitive devices and, more specifically, to processes for fabricating touch sensors for touch sensitive devices. 
     BACKGROUND 
     Touch sensitive devices have become popular as input devices to computing systems due to their ease and versatility of operation as well as their declining price. A touch sensitive device can include a touch sensor panel, which can be a clear panel with a touch sensitive surface, and a display device, such as a liquid crystal display (LCD), that can be positioned partially or fully behind the panel or integrated with the panel so that the touch sensitive surface can cover at least a portion of the viewable area of the display device. The touch sensitive device can allow a user to perform various functions by touching the touch sensor panel using a finger, stylus or other object at a location often dictated by a user interface (UI) being displayed by the display device. In general, the touch sensitive device can recognize a touch event and the position of the touch event on the touch sensor panel, and the computing system can then interpret the touch event in accordance with the display appearing at the time of the touch event, and thereafter can perform one or more actions based on the touch event. 
     One type of touch sensor panel that can be used is a capacitive touch sensor panel. Typical capacitive touch sensor panels can include a grid formed by rows of drive lines intersecting columns of sense lines. The drive lines can be driven by stimulation signals that cause the capacitively coupled sense lines to generate output touch signals representative of touch events detected on the surface of the panel. These drive lines and sense columns can be routed along the edge of a touch sensitive device to drive and sense circuitry, respectively. The thickness of the border around the edges of the touch sensitive device can depend on the number of drive lines, the number of sense lines, and the distances between each line. As touch sensitive devices continue to get smaller, it is desirable to reduce these distances between the drive and sense lines. 
     Conventionally, the drive lines and sense lines can be fabricated on the touch sensor panel using various processes, such as lithography, printing, or laser ablation. However, lithography and printing typically result in large distances between lines, and are thus in some circumstances undesirable for generating devices with thin borders. Laser ablation, on the other hand, allows for much finer patterning of the line material. However, the laser ablation process can damage the underlying substrate when patterning a line material having a high ablation fluence value, such as indium tin oxide (ITO). 
     SUMMARY 
     Processes for fabricating compact touch sensors for touch sensitive devices are disclosed. A process can include providing a touch sensor structure having a substrate, a first layer disposed on the substrate, and a second layer disposed on the first layer. The second layer can have an ablation fluence value that is lower than an ablation fluence value of the first layer. The process can include patterning the second layer with a laser emitting a beam having a fluence value greater than or equal to the ablation fluence value of the second layer and less than the ablation fluence value of the first layer. The process can further include etching at least a portion of the first layer that was exposed during the patterning of the second layer. At least a portion of the second layer can then be removed by etching or laser ablation. The processes can be used in sheet-to-sheet processes for rigid or flexible substrates or roll-to-roll processes for flexible substrates. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary touch sensor that can be used with a touch sensitive device according to various embodiments. 
         FIG. 2  illustrates an exemplary touch sensitive device according to various embodiments. 
         FIG. 3  illustrates an exemplary process for manufacturing a touch sensor according to various embodiments. 
         FIG. 4  illustrates a cross-sectional view of an exemplary touch sensor structure according to various embodiments. 
         FIG. 5  illustrates top and bottom views of an exemplary touch sensor structure according to various embodiments. 
         FIG. 6  illustrates a cross-sectional view of an exemplary touch sensor structure according to various embodiments. 
         FIG. 7  illustrates top and bottom views of an exemplary touch sensor structure according to various embodiments. 
         FIG. 8  illustrates a cross-sectional view of an exemplary touch sensor structure according to various embodiments. 
         FIG. 9  illustrates top and bottom views of an exemplary touch sensor structure according to various embodiments. 
         FIG. 10  illustrates a cross-sectional view of an exemplary touch sensor structure according to various embodiments. 
         FIG. 11  illustrates top and bottom views of an exemplary touch sensor structure according to various embodiments. 
         FIG. 12  illustrates an exemplary process for manufacturing a touch sensor according to various embodiments. 
         FIG. 13  illustrates an exemplary system for manufacturing a touch sensor according to various embodiments. 
         FIG. 14  illustrates an exemplary personal device that includes a touch sensor according to various embodiments. 
         FIG. 15  illustrates another exemplary personal device that includes a touch sensor according to various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of example embodiments, reference is made to the accompanying drawings in which it is shown by way of illustration specific embodiments that can be practiced. It is to be understood that other embodiments can be used and structural changes can be made without departing from the scope of the various embodiments. 
     This relates to processes for fabricating compact touch sensors for touch sensitive devices. A process can include providing a touch sensor structure having a substrate, a first layer disposed on the substrate, and a second layer disposed on the first layer. The second layer can have an ablation fluence value that is lower than an ablation fluence value of the first layer. An ablation fluence value of a material can refer to a fluence value (energy per unit area) of a beam emitted by a laser at which ablation of the material can occur. The process can include patterning the second layer with a laser emitting a beam having a fluence value that is greater than or equal to the ablation fluence value of the second layer and less than the ablation fluence value of the first layer. The process can further include etching at least a portion of the first layer that was exposed during the patterning of the second layer. At least a portion of the second layer can then be removed by etching or laser ablation. The processes can be used in sheet-to-sheet processes for rigid or flexible substrates or roll-to-roll processes for flexible substrates. 
       FIG. 1  illustrates touch sensor  100  that can be used to detect touch events on a touch sensitive device, such as a mobile phone, tablet, touchpad, portable computer, portable media player, or the like. Touch sensor  100  can include an array of touch regions  105  that can be formed at the crossing points between rows of drive lines  101  (D 0 -D 3 ) and columns of sense lines  103  (S 0 -S 4 ). Each touch region  105  can have an associated mutual capacitance Csig  111  formed between the crossing drive lines  101  and sense lines  103  when the drive lines are stimulated. The drive lines  101  can be stimulated by stimulation signals  107  provided by drive circuitry (not shown) and can include an alternating current (AC) waveform. The sense lines  103  can transmit touch signals  109  indicative of a touch at the touch sensor  100  to sense circuitry (not shown), which can include a sense amplifier for each sense line, or a fewer number of sense amplifiers that can be multiplexed to connect to a larger number of sense lines. 
     To sense a touch at the touch sensor  100 , drive lines  101  can be stimulated by the stimulation signals  107  to capacitively couple with the crossing sense lines  103 , thereby forming a capacitive path for coupling charge from the drive lines  101  to the sense lines  103 . The crossing sense lines  103  can output touch signals  109 , representing the coupled charge or current. When a user&#39;s finger (or other object) touches the touch sensor  100 , the finger can cause the capacitance Csig  111  to reduce by an amount ΔCsig at the touch location. This capacitance change ΔCsig can be caused by charge or current from the stimulated drive line  101  being shunted through the touching finger to ground rather than being coupled to the crossing sense line  103  at the touch location. The touch signals  109  representative of the capacitance change ΔCsig can be transmitted by the sense lines  103  to the sense circuitry for processing. The touch signals  109  can indicate the touch region where the touch occurred and the amount of touch that occurred at that touch region location. 
     While the embodiment shown in  FIG. 1  includes four drive lines  101  and five sense lines  103 , it should be appreciated that touch sensor  100  can include any number of drive lines  101  and any number of sense lines  103  to form the desired number and pattern of touch regions  105 . Additionally, while the drive lines  101  and sense lines  103  are shown in  FIG. 1  in a crossing configuration, it should be appreciated that other configurations are also possible to form the desired touch region pattern. While  FIG. 1  illustrates mutual capacitance touch sensing, other touch sensing technologies may also be used in conjunction with embodiments of the disclosure, such as self-capacitance touch sensing, resistive touch sensing, projection scan touch sensing, and the like. Furthermore, while various embodiments describe a sensed touch, it should be appreciated that the touch sensor  100  can also sense a hovering object and generate hover signals therefrom. 
       FIG. 2  illustrates a top-view of an exemplary device  200 , such as a mobile phone, touchpad, portable computer, portable media player, or the like. Device  200  can include a touch sensor  100  for detecting touch events on the display of the device. In the example shown in  FIG. 2 , touch sensor  100  can include eight drive lines  101  and six sense lines  103 . However, it should be appreciated that a touch sensor  100  having any number of drive lines  101  and sense lines  103  can be used. 
     In some examples, one end of the drive lines  101  can be routed along an edge of device  200  to a first drive line output pad or contact portion  201 , while the other end of the drive lines  101  can be routed along an opposite edge of device  200  to a second drive line output pad or contact portion  203 . The first drive line contact portion  201  and second drive line contact portion  203  can include exposed segments of each of the drive lines  101  and can be used by an external device or connector, such as a flat cable or flexible printed circuit (“FPC”), to couple to each end of the drive lines  101 . 
     In some examples, one end of a portion of the sense lines  103  can be routed to a first sense line output pad or contact portion  205 , while the remaining sense lines  103  can be routed to a second sense line output pad or contact portion  207 . Similar to the drive line contact portions  201  and  203 , sense line contact portions  205  and  207  can include exposed segments of the sense lines  103  and can be used by an external device or connector, such as a flat cable or FPC, to couple to an end of the sense lines  103 . While the example shown in  FIG. 2  includes three sense lines  103  routed to first sense line contact portion  205  and three sense lines  103  routed to the second sense line contact portion  207 , it should be appreciated that any number of sense lines  103  can be routed to any number of sense line contact portions. For example, device  200  can include ten sense lines with all ten sense lines  103  being routed to a single sense line contact portion, while in other examples, device  200  can include nine sense lines with three sense lines being routed to each of three sense line contact portions. Moreover, while  FIG. 2  shows contact portions  201 ,  203 ,  205 , and  207  along the top edge of the device, it should be appreciated that contact portions  201 ,  203 ,  205 , and  207  can be located in different areas of device  200  depending on the location of the components of device  200 , with the drive lines  101  and sense lines  103  being appropriately routed around these components to their corresponding contact portions. 
     In some examples, a cover material (e.g., glass, plastic, or the like), can be placed over the components shown in  FIG. 2 . This cover material can include a black mask along its edges to hide the portions of drive lines  101  and sense lines  103  outside the viewable area of the device from the user&#39;s view. For example, the black mask can cover the portions of drive lines  101  and sense lines located along the edges of device  200 . As can be seen in  FIG. 2 , the width of the black mask required on the right and left sides of device  200  depends on the number of drive lines  101  and the distances between the drive lines  101  along the edges of device  200 . To reduce the width of the black mask and to reduce the overall width of the device, it can be desirable to reduce the distances between the drive lines  101 . It should be appreciated that when drive lines  101  and sense lines  103  are routed in different configurations, the width of the black mask required to cover the drive lines  101  and sense lines  103  outside the viewable area of the device can additionally or alternatively depend on the number of sense lines  103  and distances between sense lines  103  and/or distances between sense lines  103  and drive lines  101 . 
       FIG. 3  illustrates an exemplary process  300  for manufacturing a touch sensor similar or identical to touch sensor  100 . Process  300  will be described below with reference to  FIGS. 4-11 . At block  301 , a touch sensor structure can be provided.  FIG. 4  illustrates an exemplary touch sensor structure  400  that can be used in process  300 . Touch sensor structure  400  can include substrate  401  made of any substrate material, such as plastic, glass, a rigid or flexible glass, or rigid or flexible composite. Touch sensor structure  400  can further include first top layer  403  disposed on the top surface of substrate  401 . First top layer  403  can include an electrically conductive material, such as ITO, copper, silver, other metals, other oxides, or the like. Touch sensor structure  400  can further include second top layer  405  disposed on a surface of first top layer  403  opposite substrate  401 . Second top layer  405  can include silver, gold, aluminum, other metals, a passivation layer, or the like. Second top layer  405  can be formed from a single layer or can include a combination of layers, such as a multilayer metal or metal-organic stack. In some examples, the material of second top layer  405  can have an ablation fluence value that is lower than an ablation fluence value of the material of the first top layer  403 . In other words, the fluence value of the laser beam required to ablate the material of second top layer  405  can be lower than the fluence value of the laser beam required to ablate the material of first top layer  403 . As will be described in greater detail below, the selection of materials having these relative ablation fluence values can allow second top layer  405  to be used as an etching mask for first top layer  403 . 
     In some examples, touch sensor structure  400  can optionally further include first bottom layer  407  disposed on the bottom surface of substrate  401 . First bottom layer  407  can include the same or a different material as first top layer  403 . For example, first bottom layer  407  can include an electrically conductive material, such as ITO, copper, other metals, other oxides, or the like. Touch sensor structure  400  can optionally further include second bottom layer  409  disposed on a surface of first bottom layer  407  opposite substrate  401 . Second bottom layer  409  can include the same or a different material as second top layer  405 . For example, second bottom layer  409  can include silver, gold, aluminum, other metals, a passivation layer, or the like. Second bottom layer  409  can be formed from a single layer or can include a combination of layers, such as a multilayer metal or metal-organic stack. In some examples, the material of second bottom layer  409  can have an ablation fluence value that is lower than an ablation fluence value of the material of the first bottom layer  407 . 
       FIG. 5  shows a top view  501  and a bottom view  503  of touch sensor structure  400 . As can be seen, the top surface of touch sensor structure  400  can be covered by second top layer  405  and the bottom surface of touch sensor structure  400  can be covered by second bottom layer  409 . 
     Referring back to  FIG. 3 , at block  303 , a second layer of the touch sensor structure can be patterned using laser ablation. In some examples, a laser, such as an Excimer Laser including but not limited to XeCl, can be applied to a surface of the touch sensor structure to generate a desired pattern. For example, as shown in  FIG. 6 , portions of second top layer  405  and second bottom layer  409  can be removed using laser ablation to form the illustrated pattern. As mentioned above, the ablation fluence value of first top layer  403  can be larger than the ablation fluence value of second top layer  405 . Thus, when a laser emits a beam having a fluence value that is greater than or equal to the ablation fluence value of second top layer  405  and less than the ablation fluence value of first top layer  403  is applied to touch sensor structure  400 , portions of second top layer  405  can be removed without removing first top layer  403 . For example, first top layer  403  can be formed from ITO having an ablation fluence value that is greater than approximately 2 J/cm 2  and second top layer  405  can be formed from a metal, such as silver or gold, having an ablation fluence value of approximately 60-100 mJ/cm 2 . Thus, a laser emitting a beam having a fluence value between 60-100 mJ/cm 2  and 2 J/cm 2  can be applied to touch sensor structure  400  to selectively remove portions of second top layer  405 . In another example, first top layer  403  can be formed from ITO and second top layer  405  can be formed from Ti. In this example, a laser emitting a beam having a fluence value between 20 mJ/cm 2  and 2 J/cm 2  (e.g., between 20-300 mJ/cm 2 ) can be applied to touch sensor structure  400  to selectively remove portions of second top layer  405 . Similarly, second bottom layer  409  can be selectively removed using a laser beam having a fluence value that is greater than or equal to the ablation fluence value of second bottom layer  409  and less than the ablation fluence value of first bottom layer  407 . 
       FIG. 7  shows top view  501  and bottom view  503  of touch sensor structure  400  after patterning touch sensor structure  400  using laser ablation at block  303 . Specifically, top view  501  shows that portions of second top layer  405  have been removed, thereby exposing first top layer  403 . The portions of second top layer  405  left intact can form columns at the center of the device and can also form strips around the edge of touch sensor structure  400 . As will be discussed in greater detail below, the portions of second top layer  405  left intact can be used as a mask and can correspond to the locations of the conductive traces used to form sense columns  103  (or alternatively drive rows  101 ) and traces used to route the sense columns  103  (or alternatively drive rows  101 ) along the edge of touch sensor structure  400 . Similarly, bottom view  503  shows the portions of second bottom layer  409  that have been removed, thereby exposing first bottom layer  407 . The portions of second bottom layer  409  left intact can form rows at the center of the device and can also form strips around the edge of touch sensor structure  400 . In some examples, the rows can be perpendicular (or at least substantially perpendicular due to manufacturing tolerances) to the columns formed in second top layer  405 . Additionally, as will be discussed in greater detail below, the portions of second bottom layer  409  left intact can be used as a mask and can correspond to the locations of the conductive traces used to form drive rows  101  (or alternatively sense columns  103 ) and traces used to route the drive rows  101  (or alternatively sense columns  103 ) along the edge of touch sensor structure  400 . While the columns of second top layer  405  and rows of second bottom layer  409  are shown as being separate from the strips of second top layer  405  and strips of second bottom layer  409  around touch sensor structure  400 , respectively, it should be appreciated that each row and each column can be coupled to a strip to be routed along the edge of touch sensor structure  400 . 
     Referring back to  FIG. 3 , at block  305 , at least a portion of a first layer of the touch sensor structure exposed after the patterning performed at block  303  can be etched. In some examples, an etchant, such as HCl:HNO 3 :H 2 O or HF:H 2 O 2 :H 2 O, can be used to etch the layer exposed after block  303  using the patterned layer as a mask. For example, as shown in  FIG. 8 , portions of first top layer  403  can be etched using second top layer  405  as a mask. The etchant used can be one that can etch the material of first top layer  403  but does not etch the material of second top layer  405  or substrate  401 . One of ordinary skill in the art can select an appropriate etchant based on the materials used for first top layer  403 , second top layer  405 , and substrate  401 . Similarly, portions of first bottom layer  407  can be etched using second bottom layer  409  as a mask. The etchant used can be one that can etch the material of first bottom layer  407  but does not etch the material of second bottom layer  409  or substrate  401 . One of ordinary skill in the art can select an appropriate etchant based on the materials used for first bottom layer  407 , second bottom layer  409 , and substrate  401 . 
       FIG. 9  shows top view  501  and bottom view  503  of touch sensor structure  400  after etching first top layer  403  and first bottom layer  407 . Specifically, top view  501  shows portions of the underlying substrate  401  after the exposed portions of first top layer  403  have been removed. Similarly, bottom view  503  shows portions of the underlying substrate  401  after the exposed portions of first bottom layer  407  have been removed. 
     Referring back to  FIG. 3 , at block  307 , at least a portion of the second layer can be removed. As shown in FIG. 10 , a portion of second top layer  405  can be removed using an ablation technique similar or identical to that used at block  303 . Alternatively, all of second top layer  405  can be removed using an ablation technique similar or identical to that used at block  303 . The laser beam used to remove some or all of second top layer  405  can have the same characteristics as that used at block  303 . Alternatively, the laser beam used to remove some or all of second top layer  405  can have a different fluence value that is greater than or equal to the ablation fluence value of the material of second top layer  405  and less than the ablation fluence value of the material of first top layer  403 . In other examples, some or all of second top layer  405  can be removed using an etching technique similar or identical to that used at block  305 . For example, portions of second top layer  405  can be removed using an etchant configured to etch second top layer  405  but not first top layer  403  and substrate  401 . The specific etchant used depends on the materials used for first top layer  403 , second top layer  405 , and substrate  401 . For example, if first top layer  403  includes ITO, second top layer  405  includes Ti, and substrate  401  includes a glass or plastic film, then an HCl:HNO 3 :H 2 O etchant can be used. 
     In some examples, the portion of second top layer  405  removed at block  307  can correspond to a viewable area of a device in which touch sensor substrate  400  is used. This can be done because in some examples, first top layer  403  can be made from an optically transparent material, such as ITO, while second top layer  405  can be made from an optically opaque material, such as silver or Ti. Thus, to avoid creating visible lines in the viewable area of a touch sensitive device, the opaque second top layer  405  can be removed in these locations. The portions of second top layer  405  outside of the viewable area can either be removed or left intact since these portions can be covered using a black mask on a cover material of the touch sensitive device. Similar or identical processes can be performed on first bottom layer  407  and second bottom layer  409 . 
       FIG. 11  shows top view  501  and bottom view  503  of touch sensor structure  400  after removing portions of second top layer  405  and second bottom layer  409 . Specifically, top view  501  shows that portions of second top layer  405  located towards the center of touch sensor structure  400  (corresponding to the viewable area of a device in which touch sensor structure  400  can be used) have been removed, thereby exposing the underlying first top layer  403 . The portions of second top layer  405  near the edges of the device (corresponding to areas outside of the viewable area of a device in which touch sensor structure  400  can be used), however, remain intact. Similarly, bottom view  503  shows that portions of second bottom layer  409  located towards the center of touch sensor structure  400  (corresponding to the viewable area of a device in which touch sensor structure  400  can be used) have been removed, thereby exposing the underlying first bottom layer  407 . Additionally, bottom view  503  shows that the portions of second bottom layer  409  near the edges of the device (corresponding to areas outside of the viewable area of a device in which touch sensor structure  400  can be used) remain intact. 
     By manufacturing a touch sensor using process  300 , compact touch sensors can be made. This is possible due to the combination of laser ablation, which can be used to finely pattern a material, and etching, which does not result in damage to the underlying substrate. Specifically, a finely patterned etching mask can be generated by ablating a mask layer (e.g., second top layer  405  and/or second bottom layer  409 ) and using that mask to etch the underlying conductive material (e.g., first top layer  403  and/or first bottom layer  407 ). In this way, drive and/or sense lines outside of the viewable area of a device (e.g., near the right and left edges of device  200  shown in  FIG. 2 ) can be placed closely together, thereby reducing the size of the device. 
       FIG. 12  illustrates an exemplary process  1200  for manufacturing a touch sensor similar or identical to touch sensor  100 . Process  1200  is similar to process  300 , except that blocks  1201  and  1203  can be used in place of block  301 . Specifically, at block  1201 , a first layer can be deposited onto a substrate. For example, a first layer similar or identical to first top layer  403  can be deposited onto, a substrate similar or identical to substrate  401  using any known deposition technique. The first layer can include an electrically conductive material, such as ITO, copper, silver, other metals, or other oxides. 
     In some examples, an additional first layer can optionally be deposited on the opposite side of the substrate. For example, a first layer similar or identical to first bottom layer  407  can be deposited onto the bottom surface of a substrate similar or identical to substrate  401 . The additional first layer can include the same or a different material as first top layer  403 . For example, the additional first layer can include an electrically conductive material, such as ITO, copper, other metals, or other oxides. 
     At block  1203 , a second layer can be deposited onto the first layer. For example, a second layer similar or identical to second top layer  405  can be deposited onto the first layer (e.g., first top layer  403 ). The second layer can include silver, gold, aluminum, other metals, a passivation layer, or the like. The second top layer can be formed from a single layer or can include a combination of layers, such as a multilayer metal or metal-organic stack. In some examples, the material of second layer can have an ablation fluence value that is lower than an ablation fluence value of the material of the first layer. The selection of materials having these relative ablation fluence values for the first layer and the second layer can allow ablation of the second layer to be used as an etching mask for the first layer. 
     In some examples, an additional second layer can optionally be deposited on the additional first layer deposited onto the opposite side of the substrate. For example, a second layer similar or identical to second bottom layer  409  can be deposited onto the additional first layer that is similar or identical to first bottom layer  407 . The additional second layer can include the same or a different material as second top layer  405 . For example, the additional second layer can include silver, gold, aluminum, other metals, a passivation layer, or the like. The second top layer can be formed from a single layer or can include a combination of layers, such as a multilayer metal or metal-organic stack. In some examples, the material of the second layer (e.g., second bottom layer  409 ) can have an ablation fluence value that is lower than an ablation fluence value of the material of the first layer (e.g., first bottom layer  407 ). 
     One or more of the functions relating to the manufacturing of a touch sensor described above can be performed by a system similar or identical to system  1300  shown in  FIG. 13 . System  1300  can include instructions stored in a non-transitory computer readable storage medium, such as memory  1303  or storage device  1301 , and executed by processor  1305 . The instructions can also be stored and/or transported within any non-transitory computer readable storage medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “non-transitory computer readable storage medium” can be any medium that can contain or store the program for use by or in connection with the instruction execution system, apparatus, or device. The non-transitory computer readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus or device, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable programmable read-only memory (EPROM) (magnetic), a portable optical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flash memory such as compact flash cards, secured digital cards, USB memory devices, memory sticks, and the like. 
     The instructions can also be propagated within any transport medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. In the context of this document, a “transport medium” can be any medium that can communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The transport medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic or infrared wired or wireless propagation medium. 
     System  1300  can further include manufacturing device  1307  coupled to processor  1305 . Manufacturing device  1307  can include deposition device  1311  configured to deposit the various layers (e.g., first top layer  403 , second top layer  405 , first bottom layer  407 , and second bottom layer  409 ) of the touch sensor structure onto the substrate, ablation device  1313  configured to ablate one or more of the layers (e.g., second top layer  405  and/or second bottom layer  409 ), and etching device  1315  configured to wet or dry etch one or more of the layers (e.g., first top layer  403 , second top layer  405 , first bottom layer  407 , and second bottom layer  409 ). Processor  1305  can control manufacturing device  1307  and its components to deposit, ablate, etch, or combinations thereof, the various layers (e.g., first top layer  403 , second top layer  405 , first bottom layer  407 , and second bottom layer  409 ) in a manner similar or identical to that described above with respect to processes  300  and/or  1200 . 
     It is to be understood that the system is not limited to the components and configuration of  FIG. 13 , but can include other or additional components in multiple configurations according to various embodiments. Additionally, the components of system  1300  can be included within a single device, or can be distributed between multiple devices. In some embodiments, processor  1305  can be located within manufacturing device  1307 . 
       FIG. 14  illustrates an exemplary personal device  1400 , such as a tablet, that can include a touch sensor according to various embodiments. 
       FIG. 15  illustrates another exemplary personal device  1500 , such as a mobile phone, that can include a touch sensor according to various embodiments. 
     Accordingly, in view of the above, some examples of the disclosure are directed to method comprising: providing a touch sensor structure comprising: a substrate; a first layer disposed on a surface of the substrate, the first layer having an associated first ablation fluence value; and a second layer disposed on a surface of the first layer opposite the substrate, the second layer having an associated second ablation fluence value that is less than the first ablation fluence value; ablating the second layer using a laser emitting energy having a fluence value that is greater than or equal to the second ablation fluence value and less than the first ablation fluence value; removing at least a portion of the first layer exposed after ablating the second layer; and removing at least a portion of the second layer after removing the portion of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the first layer exposed after ablating the second layer can include etching the portion of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the second layer after removing the portion of the first layer can include ablating the portion of the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the second layer after removing the portion of the first layer can include etching the portion of the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the substrate below the portion of the first layer can be exposed after removing the portion of the first layer. 
     Some examples of the disclosure are directed to a method comprising: depositing a first layer onto a substrate, the first layer having an associated first ablation fluence value; depositing a second layer on the first layer, the second layer having an associated second ablation fluence value that is less than the first ablation fluence value; patterning the second layer using a laser emitting energy having a fluence value greater than or equal to the second ablation fluence value and less than the first ablation fluence value; removing at least a portion of the first layer exposed after patterning the second layer; and removing at least a portion of the second layer after removing the portion of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the second layer can include etching the portion of the second layer using an etchant configured to etch the second layer without etching the first layer and the substrate. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the second layer can include ablating the portion of the second layer using the laser emitting energy having the fluence value that is greater than or equal to the second ablation fluence value and less than the first ablation fluence value. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first layer can include indium tin oxide and the second layer can include Ti, and wherein the fluence value of the energy emitted by the laser used to pattern the second layer can be between 20-300 mJ/cm 2 . Additionally or alternatively to one or more of the examples disclosed above, in some examples, patterning the second layer can include ablating the second layer to form: a plurality of rows; and a plurality of strips along edges of the substrate that are connected to the plurality of rows. 
     Some examples of the disclosure are directed to a method comprising: providing a touch sensor structure comprising: a substrate; a first layer disposed on a surface of the substrate, the first layer having an associated first ablation fluence value; and a second layer disposed on a surface of the first layer opposite the substrate, the second layer having an associated second ablation fluence value that is less than the first ablation fluence value; ablating the second layer using a laser emitting energy having a fluence value that is greater than or equal to the second ablation fluence value and less than the first ablation fluence value; and removing at least a portion of the first layer exposed after ablating the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include removing at least a portion of the second layer after removing the portion of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the substrate can further include: a third layer disposed on a surface of the substrate opposite the first layer, the third layer having an associated third ablation fluence value; and a fourth layer disposed on a surface of the third layer opposite the substrate, the further layer having an associated fourth ablation fluence value that is less than the third ablation fluence value. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include: ablating the fourth layer using a laser emitting energy having a fluence value that is greater than or equal to the fourth ablation fluence value and less than the third ablation fluence value; and removing at least a portion of the third layer exposed after ablating the fourth layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include removing at least a portion of the fourth layer after removing the portion of the third layer. 
     Some examples of the disclosure are directed to a method comprising: depositing a first layer onto a surface of a substrate, the first layer having an associated first ablation fluence value; depositing a second layer on a surface of the first layer opposite the substrate, the second layer having an associated second ablation fluence value that is less than the first ablation fluence value; patterning the second layer using a laser emitting energy having a fluence value greater than or equal to the second ablation fluence value and less than the first ablation fluence value; and removing at least a portion of the first layer exposed after patterning the second layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include removing at least a portion of the second layer after removing the portion of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include depositing a third layer onto a surface of the substrate opposite the first layer, the third layer having an associated third ablation fluence value; depositing a fourth layer on a surface of the third layer opposite the substrate, the fourth layer having an associated fourth ablation fluence value that is less than the third ablation fluence value; patterning the fourth layer using a laser emitting energy having a fluence value greater than or equal to the fourth ablation fluence value and less than the third ablation fluence value; and removing at least a portion of the third layer exposed after patterning the fourth layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the method can further include removing at least a portion of the fourth layer after removing the portion of the third layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the fourth layer after removing the portion of the third layer can include ablating the portion of the fourth layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, removing the portion of the fourth layer after removing the portion of the third layer can include etching the portion of the fourth layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, patterning the second layer can include patterning the second layer to form a plurality of columns, and wherein patterning the fourth layer can include patterning the fourth layer to form a plurality of rows that are at least substantially perpendicular to the plurality of columns. 
     Some examples of the disclosure are directed to a touch sensitive device comprising: a plurality of conductive traces formed by ablating a first layer according to a first fluence value so as to form a pattern for the plurality of conductive traces and etching a second layer to match the pattern, the etched second layer being the conductive traces. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the first fluence value can be greater than or equal to an ablation fluence value of the second layer and less than an ablation fluence value of the first layer. Additionally or alternatively to one or more of the examples disclosed above, in some examples, the second layer can include indium tin oxide and the first layer can include Ti, and wherein the first fluence value is between 20-300 mJ/cm 2 . 
     Although embodiments have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the various embodiments as defined by the appended claims.

Metadata:
Filing Date: 20130304
Publication Date: 20180306
Grant Date: 20180306
Priority Date: 20120305
Inventors: MOHAPATRA SIDDHARTH
KANG SUNGGU
ZHONG JOHN Z.
Assignee: APPLE INC
CPC Classifications: [{"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H11/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y10T29/49105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01H11/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49105", "inventive": false, "first": false, "tree": "[]"}, {"code": "H03K17/9622", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0446", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49105", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04103", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49042199