HK1141102A - Method for transferring thin film to substrate - Google Patents

Description

Method for transferring thin film to substrate

Technical Field

The present invention relates generally to transferring thin films to target substrates, and more particularly to transferring a single layer thin film of conductive material from a temporary surface to a touch-sensitive surface.

Background

There are many types of input devices currently available for performing operations in computing systems, such as buttons or keys, mice, trackballs, touch sensor panels, joysticks, touch screens, and the like. In particular, touch screens are becoming increasingly popular due to their ease and versatility of operation and their declining price. The touch screen may include: a touch sensor panel, which may be a transparent panel having a touch-sensitive surface; and a display device, such as an LCD panel, which may be located partially or completely behind the touch sensor panel such that the touch sensitive surface may cover at least a portion of the viewable area of the display device. Touch screens can allow a user to perform various functions by touching the touch sensor panel with a finger, stylus (stylus), or other object at a location indicated by a User Interface (UI) being displayed by the display device. In general, a touch screen may recognize a touch event and the location on the touch sensor panel where the touch event occurred, and a computing system may then interpret the touch event according to the display that occurred when the touch event occurred, and may thereafter perform one or more actions based on the touch event.

In some embodiments, a touch sensor panel can be implemented as an array of pixels formed of a conductive material, such as Indium Tin Oxide (ITO), patterned into drive lines that span sense lines and separated from each other by dielectric materials. The conductive material may be disposed on a back side of the touch-sensitive surface to detect a touch received on a front side of the touch-sensitive surface. The drive lines and the sense lines can be formed on opposite sides of a substrate. Alternatively, the drive lines and the sense lines can be formed adjacent to each other or in close proximity on the same layer on a single side of a substrate. A typical substrate for the conductive material may be made of glass or some other transparent substrate that is strong enough to directly fabricate the drive and sense lines thereon. However, with the increasing demand for smaller, thinner, flexible, and non-planar touch sensor panels, it can be difficult and expensive to fabricate the drive and sense lines directly on the substrate required for such panels.

Disclosure of Invention

The present invention relates to transferring a single-layer thin film of conductive material from a temporary substrate to a target substrate for use in a device such as a touch sensor panel. In some embodiments, the transfer may be accomplished by means of the following actions: manufacturing a block including a base layer, a single-layer film and a temporary substrate; transferring the block to a target substrate; and removing the temporary substrate. In some embodiments, the transfer may be accomplished by means of the following actions: manufacturing a large block including a base layer, a single-layer film and a temporary substrate; cutting the large block into smaller individual blocks; transferring each small individual block to a target substrate; and removing the temporary substrate from each small individual block.

Drawings

FIG. 1a illustrates an exemplary thin film block having a fabrication sheet with a base layer on a surface of the sheet according to embodiments of the invention;

FIG. 1b illustrates the exemplary thin film block shown in FIG. 1a with a single layer of thin film patterned on a surface of the base layer, in accordance with embodiments of the present invention;

FIG. 1c illustrates the exemplary thin film block shown in FIG. 1b with a transfer layer adhered to the patterned single layer thin film by means of a removable adhesive, according to embodiments of the invention;

FIG. 1d illustrates the exemplary thin film block shown in FIG. 1c with the fabrication sheet removed therefrom according to an embodiment of the invention;

FIG. 1e illustrates an exemplary substrate with the exemplary thin film block shown in FIG. 1d transferred to a surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention;

FIG. 1f illustrates the removal of the transfer layer from the thin film block according to embodiments of the invention

The exemplary substrate and thin film block shown in FIG. 1 e;

FIG. 2 illustrates an exemplary method for transferring a thin film to a substrate according to an embodiment of the invention;

FIG. 3 illustrates another exemplary method for transferring a thin film to a substrate according to an embodiment of the invention;

FIG. 4a illustrates an exemplary curved substrate with an exemplary thin film block transferred to a recessed surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention;

FIG. 4b illustrates an exemplary curved substrate with an exemplary thin film block transferred to a raised surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the invention;

FIG. 4c illustrates an exemplary substrate having a convex surface and a flat surface with an exemplary thin film block transferred to the flat surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention;

FIG. 4d illustrates an exemplary substrate having a concave surface and a flat surface with an exemplary thin film block transferred to the flat surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention;

FIG. 5a illustrates an exemplary thin film block having a fabrication sheet with a base layer on a surface of the sheet according to embodiments of the invention;

FIG. 5b illustrates the exemplary thin film block shown in FIG. 5a patterned with two spaced-apart single-layer thin films on one surface of the base layer, according to embodiments of the invention;

FIG. 5c illustrates the exemplary thin film block shown in FIG. 5b with a transfer layer adhered to the outermost of the patterned single thin films by means of a removable adhesive, according to embodiments of the invention;

FIG. 5d illustrates the exemplary thin film block shown in FIG. 5c with the fabrication sheet removed therefrom according to an embodiment of the invention;

FIG. 5e illustrates an exemplary substrate with the exemplary thin film block shown in FIG. 5d transferred to a surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention;

FIG. 5f illustrates the exemplary substrate and thin film block shown in FIG. 5e with the transfer layer removed from the thin film block according to an embodiment of the invention;

FIG. 6 illustrates another exemplary method for transferring a thin film to a substrate according to embodiments of the invention;

FIG. 7a illustrates an exemplary mobile phone having a touch sensor panel including a film transferred thereto in accordance with embodiments of the present invention;

FIG. 7b illustrates an exemplary digital media player having a touch sensor panel including a film transferred thereto in accordance with embodiments of the present invention;

FIG. 7c illustrates an exemplary computer having a touch sensor panel including a film transferred thereto in accordance with embodiments of the present invention; and

FIG. 8 illustrates an exemplary computing system including a touch sensor panel utilizing a film transferred thereto in accordance with embodiments of the present invention.

Detailed Description

In the following description of the preferred embodiments, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the preferred embodiments of the present invention.

The present invention relates to the transfer of a single layer thin film of conductive material to a substrate for use in devices such as touch sensor panels. In some embodiments, transfer may be accomplished by patterning a single layer of conductive material on one side of a transfer substrate and then transferring the patterned material from the transfer substrate onto a target substrate. This advantageously allows the patterned material to be transferred to any target substrate, which may be a substrate that is not tolerant of standard fabrication processes (e.g., a soft plastic substrate or a very thin substrate), or a substrate that does not fit standard fabrication equipment (e.g., a non-flat substrate).

Although embodiments of the invention are described and illustrated herein in terms of touch sensor panels, it should be understood that embodiments of the invention are not limited to such panels, but are generally applicable to panels utilizing other touch and proximity sensing technologies and any substrate to which a fabrication film may be transferred.

FIG. 1a illustrates an exemplary thin film block having a fabrication sheet with a base layer on a surface of the sheet according to embodiments of the invention. In the example of FIG. 1a, sheet 105 has a base layer 110 disposed on a surface. The sheet 105 may comprise glass or any other suitable material capable of providing a temporary platform for fabricating a thin film block and then being easily removed from the block. The base layer 110 may comprise an etch stop material such as silicon nitride, silicon dioxide, or any other suitable material that is inert to the chemicals (e.g., hydrogen fluoride) that may be used to remove the sheet 105 by means of chemical etching. The base layer 110 may be deposited on the surface of the sheet 105 by means of Plasma Enhanced Chemical Vapor Deposition (PECVD) or any other suitable deposition method. The base layer 110 may be rigid, semi-rigid, flexible, or deformable depending on the application of the thin film block.

FIG. 1b illustrates the exemplary thin film block shown in FIG. 1a patterned with a single layer of thin film on a surface of the base layer, in accordance with embodiments of the present invention. In the example of fig. 1b, the pattern of thin film 115 may be deposited as a single layer on one surface of the substrate layer 110. The thin film pattern may be used as a conductive trace for carrying a signal and may include a transparent material such as a single layer of indium tin oxide (SITO). Although SITO may be referred to herein for illustrative purposes, it should be understood that other conductive materials may also be used in accordance with embodiments of the present invention. The thin film pattern may form part of a touch sensor for carrying touch imagery in a touch sensitive device, such as a touch panel. The patterned thin film may be deposited on a surface of the base layer using sputtering or any other suitable method for disposing the patterned thin film 115 on the base layer 110.

FIG. 1c illustrates the exemplary thin film block shown in FIG. 1b with a transfer layer adhered to the patterned single layer thin film by means of a removable adhesive, according to embodiments of the invention. In the example of fig. 1c, a layer of removable adhesive 120 may coat the patterned thin film 115. The removable adhesive 120 may comprise a water insoluble glue or any other suitable material capable of temporarily adhering two layers together and then being dissolved or otherwise removed. A transfer layer 125 may be placed on top of the removable adhesive 120, which helps adhere the transfer layer to the underlying patterned thin film 115. The transfer layer 125 may comprise a polymer such as polyethylene terephthalate (PET) or any other suitable material capable of supporting a thin film block for transfer to a substrate in accordance with embodiments of the present invention. The transfer layer 125 can be laminated or otherwise placed on the removable adhesive 120. The transfer layer 125 may be rigid, semi-rigid, flexible, or deformable depending on the application of the thin film block.

FIG. 1d illustrates the exemplary thin film block shown in FIG. 1c with the fabrication sheet removed, according to an embodiment of the invention. In the example of FIG. 1d, the sheet 105 may be removed in preparation for transferring the thin film block to a substrate. The sheet 105 may be removed by means of chemical etching using a chemical such as hydrogen fluoride. Alternatively, the sheet 105 may be removed by means of a mechanical method or a combined chemical-mechanical method.

FIG. 1e illustrates an exemplary substrate having the exemplary thin film block shown in FIG. 1d transferred to a surface thereof and adhered thereto by means of a permanent adhesive, in accordance with embodiments of the present invention. In the example of FIG. 1e, a layer of permanent adhesive 130 may be laminated or otherwise adhered to the base layer 110 of the thin film block. The permanent adhesive 130 may be adhered to the surface of the base layer 110 opposite the base layer surface on which the patterned thin film 115 is disposed. The permanent adhesive 130 may be laminated or otherwise adhered to a surface of the substrate 140 along with the thin film block. Thus, the stacking order may be the substrate 140, the permanent adhesive 130, the base layer 110, the patterned thin film 115, the removable adhesive 120, and the transfer layer 125. Optionally, opaque material 135 may be adhered to the edges of substrate 140 and permanent adhesive 130 to provide an aesthetic edge for the substrate. The permanent adhesive 130 may comprise a water insoluble glue or any other suitable material capable of permanently adhering two layers together. The substrate 140 may comprise glass, plastic, or any other transparent material. The substrate 140 may be rigid, semi-rigid, flexible, or deformable depending on the application of the substrate. In some embodiments, the substrate 140 can be a cover material for a touch sensitive device, wherein the front side of the substrate 140 can receive a touch and the back side of the substrate can have a thin film block transferred thereto to detect the received touch.

FIG. 1f illustrates the exemplary substrate and thin film block shown in FIG. 1e with the transfer layer removed from the thin film block according to embodiments of the invention. In the example of fig. 1f, the transfer layer 125 can be removed from the patterned thin film 115 by peeling (delaminating) or otherwise removing the transfer layer from the removable adhesive 120, and then by dissolving or otherwise removing the removable adhesive from the thin film. Alternatively, the removable adhesive 120 can be dissolved or otherwise removed from the film, thereby removing the transfer layer 125 along with the removable adhesive 120. The resulting substrate and thin film block are now ready for further processing. In some embodiments, an end of a flex circuit may be bonded to the patterned thin film 115, and an anti-reflective film may be laminated or otherwise coated over the patterned thin film 115 to further form a touch sensitive device. Optionally, one or more spacers may be attached to the anti-reflective film to provide connections for other components of the touch sensitive device.

FIG. 2 illustrates an exemplary method for transferring a thin film to a substrate according to an embodiment of the invention. A glass sheet may be provided as a temporary platform for making a transferable thin film block. An etch stop layer (e.g., base layer 110 in fig. 1 a) may be applied to the glass sheet 205. The etch stop layer may be deposited, laminated or otherwise applied to the sheet. A single layer of film 210 may be patterned on a surface of the etch stop layer. For example, the patterned thin film may be SITO. A transfer layer may be adhered to the patterned single layer by means of a removable adhesive (215). The removable adhesive may be applied to the patterned thin film and then the transfer layer laminated or otherwise placed on top of the removable adhesive.

After the transferable thin film block has been fabricated, the glass sheet (220) may be removed. To do so, the thin film block may be exposed to an etching chemistry that etches away the glass sheet. The etch stop layer may protect the remaining portions of the thin film block from chemical damage. Alternatively, mechanical methods may be used to remove the glass flakes. The remaining thin film block (including the transfer layer, removable adhesive, patterned thin film, and etch stop layer) may be transferred to a substrate and adhered to the substrate using permanent adhesive (225). The permanent adhesive may be laminated or otherwise adhered to the etch stop layer and then laminated or otherwise adhered to a surface of the substrate. Thus, the etch stop layer may be closest to the substrate, followed by the patterned thin film, followed by the removable adhesive, and the transfer layer furthest from the substrate.

The transfer layer and the removable adhesive (230) may be removed from the patterned thin film. The removable adhesive may be dissolved in a solvent or otherwise removed, thereby removing the transfer layer along with the removable adhesive. Alternatively, the transfer layer may be peeled or otherwise removed from the removable adhesive, and then the removable adhesive is dissolved or otherwise removed from the patterned thin film. The resulting substrate-film block combination may be further processed to provide a suitable circuit.

In an alternative embodiment, the etch stop layer may be replaced by a plastic or polyimide layer that may be bonded to the glass sheet. The glass sheet may then be removed from the thin film block by de-bonding the sheet to the plastic or polyimide layer.

FIG. 3 illustrates another exemplary method for transferring a thin film to a substrate according to an embodiment of the invention. For cost effectiveness, multiple thin film blocks can be fabricated at once on a large glass sheet and then separated for transfer to separate substrates. In the example of FIG. 3, a large sheet of glass may be provided upon which a plurality of thin film blocks are to be fabricated from a large thin film block. Large thin film blocks (305) can be fabricated on the glass sheet. The large thin film block may have a base layer formed on the glass sheet, a single thin film (e.g., SITO) patterned on a surface of the base layer, a removable adhesive layer formed on the patterned thin film, and a transfer layer formed on the removable adhesive layer. The large thin film block may be fabricated using, for example, the method of fig. 2.

The glass sheet and the film modules fabricated thereon may be die cut into a plurality of smaller blocks (310). The smaller blocks may be cut to any size suitable for transfer to a substrate. Each smaller block may include a portion of the glass sheet, a portion of the base layer formed on the glass sheet portion, a portion of the patterned thin film formed on the base layer portion, a portion of the removable adhesive formed on the patterned thin film portion, and a portion of the transfer layer formed on the removable adhesive portion.

For each smaller chunk, the glass sheet portion may be removed using, for example, the method of fig. 2. The remainder of the smaller film block may be applied to a separate cover glass (315) with the aid of a permanent adhesive. The smaller thin film block may be applied using, for example, the method of fig. 2. The transfer layer and the removable adhesive may be removed 320 from the patterned thin film using, for example, the method of fig. 2. A flex circuit may be attached to the patterned thin film to form a touch panel, wherein the cover glass may receive a touch and the thin film block attached thereto may detect the touch (325). Optionally, an anti-reflective layer or any other suitable layer may be coated with the patterned thin film, and a spacer may be attached to the anti-reflective layer to connect other components.

Fig. 4 a-4 d illustrate an exemplary curved substrate having an exemplary thin film block transferred thereto, according to an embodiment of the invention. In the example of fig. 4a, the base layer 410 may be adhered to a concave surface of the curved substrate 440 by means of a permanent adhesive 430. A patterned single layer thin film 415 may be disposed on a surface of the base layer 410. In the example of fig. 4b, the base layer 410 may be adhered to a convex surface of the curved substrate 440 by means of a permanent adhesive 430. A patterned single layer thin film 415 may be disposed on a surface of the base layer 410. In the example of fig. 4c, the curved substrate 440 may have a convex surface and a flat surface opposite the convex surface. The base layer 410 may be adhered to the flat surface of the curved substrate 440 by means of a permanent adhesive 430. A patterned single layer thin film 415 may be disposed on a surface of the base layer 410. In the example of fig. 4d, the curved substrate 440 may have a concave surface and a flat surface opposite the concave surface. The base layer 410 may be adhered to the flat surface of the curved substrate 440 by means of a permanent adhesive 430. A patterned single layer thin film 415 may be disposed on a surface of the base layer 410.

The curved substrate may be rigid, semi-rigid, flexible, or deformable. The rigid curved substrate may be permanently formed to be curved. The semi-rigid, flexible and deformable curved substrate may be dynamically formed to be curved and not formed to be curved. It should be understood that the substrate is not limited to a curved shape, but may include any substantially non-planar surface with which a transferred thin film block can be associated in accordance with embodiments of the present invention.

FIG. 5a illustrates an exemplary thin film block having a fabrication sheet with a base layer on a surface of the sheet according to embodiments of the invention. In the example of fig. 5a, sheet 505 has a base layer 510 disposed on a surface. The sheet 505 may comprise glass or any other suitable material capable of providing a temporary platform for fabricating a thin film block and then being easily removed from the block. The base layer 510 may comprise an etch stop material such as silicon nitride, silicon dioxide, or any other suitable material that is inert to the chemicals (e.g., hydrogen fluoride) that may be used to remove the sheet 505 by means of chemical etching. The base layer 510 may be deposited on the surface of the sheet 505 by means of PECVD or any other suitable deposition method. The base layer 510 may be rigid, semi-rigid, flexible, or deformable depending on the application of the thin film block.

FIG. 5b illustrates the exemplary thin film block shown in FIG. 5a patterned with two spaced-apart single-layer thin films on one surface of the base layer, according to embodiments of the invention. In the example of fig. 5b, the pattern of thin film 515 may be deposited as a single layer on one surface of the base layer 510. The thin film pattern may be used as conductive traces for carrying signals and may include a transparent material, such as ITO. The thin film pattern may form part of a touch sensor for carrying touch imagery in a touch sensitive device, such as a touch panel. The patterned thin film 515 may be deposited on a surface of the base layer using sputtering or any other suitable method for disposing the patterned thin film on the base layer 510.

A separation layer 545 may be disposed on the patterned thin film 515. The pattern of thin film 550 may be deposited as a single layer on a surface of the separation layer 545 opposite to the surface of the separation layer 545 disposed on the patterned thin film 515. Like the patterned thin film 515, the thin film pattern 550 may be used as conductive traces for carrying signals and may comprise a transparent material, such as ITO. The thin film pattern may form part of a touch sensor for carrying images of touches in a touch sensitive device, such as a touch panel. Sputtering or any other suitable method for disposing the patterned thin film 550 on the separation layer 545 may be used to deposit the patterned thin film on a surface of the separation layer. The separation layer 545 may be rigid, semi-rigid, flexible, or deformable depending on the application of the thin film block. The separation layer 545 may be glass or some other transparent dielectric material. The patterned thin films 515, 550 may be formed as a double layer of indium tin oxide (DITO) on opposite sides of the separation layer 545.

In an alternative embodiment, the separation layer 545 may be omitted and the patterned thin films 515, 550 may be formed as dual SITO on top of each other.

FIG. 5c illustrates the exemplary thin film block shown in FIG. 5b with a transfer layer adhered to the outermost of the patterned single layer thin films by means of a removable adhesive, according to embodiments of the invention. In the example of fig. 5c, a layer of removable adhesive 520 may coat the outermost layer of the patterned thin film 550. The removable adhesive 520 may comprise a water insoluble glue or any other suitable material capable of temporarily adhering two layers together and then being dissolved or otherwise removed. A transfer layer 525 may be placed on top of the removable adhesive 520, which helps adhere the transfer layer to the underlying patterned thin film 515. The transfer layer 525 may comprise a polymer such as PET or any other suitable material capable of supporting a thin film block for transfer to a substrate in accordance with embodiments of the present invention. The transfer layer 525 may be laminated or otherwise placed on the removable adhesive 520. The transfer layer 525 may be rigid, semi-rigid, flexible, or deformable depending on the application of the thin film block.

FIG. 5d illustrates the exemplary thin film block shown in FIG. 5c with the fabrication sheet removed, according to an embodiment of the invention. In the example of FIG. 5d, sheet 505 may be removed in preparation for transferring the thin film block to a substrate. The sheet 505 may be removed by means of chemical etching using a chemical such as hydrogen fluoride. Alternatively, the sheet 505 may be removed by means of a mechanical method or a combined chemical-mechanical method.

FIG. 5e illustrates an exemplary substrate with the exemplary thin film block shown in FIG. 5d transferred to a surface of the substrate and adhered to the substrate by means of a permanent adhesive, in accordance with embodiments of the present invention. In the example of fig. 5e, a layer of permanent adhesive 530 may be laminated or otherwise adhered to the base layer 510 of the thin film block. The permanent adhesive 530 may be adhered to a surface of the base layer 510 opposite the base layer surface on which the patterned thin film 515 is disposed. The permanent adhesive 530 may be laminated or otherwise adhered to a surface of the substrate 540 along with the thin film block. Thus, the stacking order may be the substrate 540, the permanent adhesive 530, the base layer 510, the patterned thin film 515, the separation layer 545, the second patterned thin film 550, the removable adhesive 520, and the transfer layer 525. Optionally, an opaque material 535 may be adhered to the edges of the substrate 540 and the permanent adhesive 530 to provide an aesthetic edge for the substrate. The permanent adhesive 530 may comprise a water insoluble glue or any other suitable material capable of permanently adhering two layers together. The substrate 540 may comprise glass, plastic, or any other transparent material. The substrate 540 may be rigid, semi-rigid, flexible, or deformable depending on the application for which the substrate is used. In some embodiments, the substrate 540 can be a cover material for a touch sensitive device, wherein the front side of the substrate 540 can receive a touch and the back side of the substrate can have a thin film block transferred thereto to detect the received touch.

FIG. 5f illustrates the exemplary substrate and thin film block shown in FIG. 5e with the transfer layer removed from the thin film block according to embodiments of the invention. In the example of fig. 5f, the transfer layer 525 may be removed from the patterned thin film 550 by peeling or otherwise removing the transfer layer from the removable adhesive 520, and then by dissolving or otherwise removing the removable adhesive from the thin film. Alternatively, the removable adhesive 520 can be dissolved or otherwise removed from the film 550, thereby removing the transfer layer 525 along with the removable adhesive 520. The resulting substrate and thin film block are now ready for further processing. In some embodiments, an end of a flex circuit may be bonded to one or both of the patterned thin films 515, 550, and an anti-reflective film may be laminated or otherwise coated onto the patterned thin film 550 to further form a touch sensitive device. Optionally, one or more spacers may be attached to the anti-reflective film to provide connections for other components of the touch sensitive device.

FIG. 6 illustrates an exemplary method for transferring a thin film to a substrate according to an embodiment of the invention. A glass sheet may be provided as a temporary platform for making a transferable thin film block. An etch stop layer may be applied to the glass sheet 605. The etch stop layer may be deposited, laminated or otherwise applied to the sheet. One or more single-layer films 610 may be patterned on a surface of the etch stop layer. For multiple layers, a separation layer may be deposited between each patterned thin film. For example, the patterned thin film can be SITO, DITO, or dual SITO. A transfer layer may be adhered to the outermost layer of the patterned single layers by means of a removable adhesive (615). The removable adhesive may be applied to the patterned thin film and then the transfer layer laminated or otherwise placed on top of the removable adhesive.

After the transferable thin film block has been fabricated, the glass sheet can be removed (620). To do so, the thin film block may be exposed to an etching chemistry that etches away the glass sheet. The etch stop layer may protect the remaining portions of the thin film block from chemical damage. Alternatively, mechanical methods may be used to remove the glass flakes. The remaining thin film block (including the transfer layer, removable adhesive, patterned thin film(s), separation layer(s), and etch stop layer) may be transferred to a substrate and adhered to the substrate using permanent adhesive (625). The permanent adhesive may be laminated or otherwise adhered to the etch stop layer and then laminated or otherwise adhered to a surface of the substrate. Thus, the etch stop layer may be closest to the substrate, followed by the one or more patterned thin films and separation layers, followed by the removable adhesive, and the transfer layer furthest from the substrate.

The transfer layer and the removable adhesive may be removed from the patterned thin film 630. The removable adhesive may be dissolved in a solvent or otherwise removed, thereby removing the transfer layer along with the removable adhesive. Alternatively, the transfer layer may be peeled or otherwise removed from the removable adhesive, and then the removable adhesive is dissolved or otherwise removed from the patterned thin film. The resulting substrate-film block combination may be further processed to provide a suitable circuit.

In an alternative embodiment, the etch stop layer may be replaced by a plastic or polyimide layer that may be bonded to the glass sheet. The sheet may then be removed from the thin film block by debonding the glass sheet from the plastic or polyimide layer.

Fig. 7a illustrates an exemplary mobile telephone 736 that can include touch sensor panel 724, display device 730, and other computing system modules, wherein the touch sensor panel can have a plurality of co-planar single-layer touch sensors fabricated in a single layer on one side of a transfer substrate and transferred from the transfer substrate to the back side of the touch sensor panel.

Fig. 7b illustrates an exemplary digital media player 740 that can include a touch sensor panel 724, a display device 730, and other computing system modules, where the touch sensor panel can have a plurality of co-planar single-layer touch sensors fabricated in a single layer on one side of a transfer substrate and transferred from the transfer substrate to the back side of the touch sensor panel.

Fig. 7c illustrates an exemplary personal computer 744 that can include a touch sensor panel (trackpad) 724 and a display 730 and other computing system modules, where the touch sensor panel can have a plurality of co-planar single-layer touch sensors fabricated in a single layer on one side of a transfer substrate and transferred from the transfer substrate to the back side of the touch sensor panel.

The mobile phones, media players and personal computers of fig. 7a, 7b and 7c may have touch sensors that are easy to manufacture and transfer according to embodiments of the invention.

FIG. 8 illustrates an exemplary computing system 800 that can include one or more of the above-described embodiments of the invention. Computing system 800 can include one or more panel processors 802 and peripherals 804, and panel subsystem 806. Peripherals 804 can include, but are not limited to, Random Access Memory (RAM) or other types of memory or storage, watchdog timers, and the like. Panel subsystem 806 can include, but is not limited to, one or more sense channels 808, channel scan logic 810, and driver logic 814. Channel scan logic 810 can access RAM 812, autonomously read data from the sense channels, and provide control for the sense channels. In addition, channel scan logic 810 can control driver logic 814 to generate stimulation signals 816 of various frequencies and phases that can be selectively applied to drive lines of touch sensor panel 824. In some embodiments, panel subsystem 806, panel processor 802, and peripherals 804 can be integrated into a single Application Specific Integrated Circuit (ASIC).

Touch sensor panel 824 can include a capacitive sensing medium having a plurality of drive lines and a plurality of sense lines, although other sensing media can be used. According to embodiments of the invention, either or both of the drive and sense lines can be fabricated on a transfer substrate and transferred from the transfer substrate to the touch sensor panel. Each intersection of drive and sense lines can represent a capacitive sensing node and can be viewed as picture element (pixel) 826, which can be particularly useful when touch sensor panel 824 is viewed as capturing an "image" of touch. (in other words, after panel subsystem 806 has determined whether a touch event has been detected at each touch sensor in the touch sensor panel, the pattern of touch sensors in the multi-touch panel at which the touch event occurred can be considered as an "image" of touch (e.g., a pattern of fingers touching the panel)). Each sense line of touch sensor panel 824 can drive a sense channel 808 (also referred to herein as event detection and demodulation circuitry) in panel subsystem 806.

Computing system 800 may also include a host processor 828 for receiving output from panel processor 802 and performing actions based on the output, which actions may include, but are not limited to, moving an object such as a cursor or pointer, scrolling or panning (pan), adjusting control settings, opening a file or document, viewing a menu, making a selection, executing instructions, operating a peripheral device coupled to the host device, answering a call, making a call, hanging up a call, changing volume or audio settings, storing information related to telephone communications (such as an address, frequently dialed number, answered incoming call, missed incoming call), logging into a computer or computer network, granting authorized personal access to a restricted area of the computer or computer network, loading user settings associated with a computer desktop configuration preferred by a user, granting access to web content, accessing a web content, a web browser, or a, Initiate a specific procedure, encrypt or decode a message, and/or the like. Host processor 828 may also perform additional functions that may not be related to panel processing and may be coupled to program storage 832 and display device 830, such as an LCD panel, to provide a UI to a user of the device. Display device 830 in conjunction with touch sensor panel 824, when located partially or completely beneath the touch sensor panel, can form touch screen 818.

Note that one or more of the functions described above can be performed by firmware stored in memory (e.g., one of peripherals 804 in fig. 8) and executed by panel processor 802, or stored in program storage 832 and executed by host processor 828. The firmware can also be stored and/or transmitted within any computer-readable 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 "computer-readable 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 computer readable 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 disk (such as a CD, CD-R, CD-RW, DVD-R, or DVD-RW), or flash memory (such as compact flash cards, secure digital cards, USB memory devices, memory sticks, and the like).

The firmware 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 "transmission 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 transmission readable medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, or infrared wired or wireless propagation medium.

Accordingly, in some embodiments, a method for transferring a thin film to a substrate is disclosed, the method comprising: providing a flexible transfer block on a fabrication sheet, the flexible transfer block comprising a flexible layer placed on the fabrication sheet, a patterned single layer thin film formed on top of the flexible layer, and a transfer layer adhered on top of the patterned single layer; removing the fabrication sheet from the flexible layer; transferring the flexible transfer block to a substrate having a substantially non-planar surface such that the flexible layer is adjacent to the substrate; and removing the transfer layer from the patterned single layer.

In some embodiments where the substantially non-planar surface is a curved surface, the flexible transfer block is transferred to the curved surface of the substrate to conform thereto.

In some embodiments where the substantially non-planar surface is a curved surface opposite a substantially planar surface, the flexible transfer block is transferred to the substantially planar surface of the substrate.

In some embodiments where the substrate is deformable to form a substantially non-planar surface, the flexible transfer block deforms with the substrate to conform to the deformable substantially non-planar surface of the substrate.

In some embodiments where the substrate is flexible so as to form a substantially non-planar surface, the flexible transfer block flexes with the substrate so as to conform to the flexible substantially non-planar surface of the substrate.

In some embodiments, a method for transferring a thin film to a substrate is disclosed, the method comprising: forming a thin film block having a base layer formed on a fabrication sheet, a single layer thin film forming a pattern on the base layer, and a temporary layer adhered on top of the patterned single layer; cutting the thin film block into smaller blocks, each having a portion of the fabrication sheet, a portion of the base layer formed on the portion of the transparent sheet, a portion of the single layer thin film forming a pattern on the portion of the base layer, and a portion of the temporary layer adhered on top of the portion of the patterned single layer; and for each smaller block, removing the portion of the fabrication sheet from the portion of the base layer, applying the combined portions of the base layer, the patterned single layer, and the temporary layer to a surface of a cover glass, the portion of the base layer adhering to the surface of the cover glass, and removing the portion of the temporary layer from the portion of the patterned single layer.

In some embodiments, the method further comprises: for each smaller block, a flex circuit is attached to the portion of the patterned single layer after removing the portion of the temporary layer.

In some embodiments, the method further comprises: for each smaller block, an anti-reflective layer is applied to the portion of the patterned single layer after removing the portion of the temporary layer.

In some embodiments, the cover glass has a front surface configured to receive a contact and a back surface opposite the front surface, the back surface adhered to the portion of the base layer.

In some embodiments, the cover glass and the combined portion of the base layer and the patterned single layer form a touch sensitive device.

In some embodiments, in a system including a sensor panel having a touch-sensitive surface with a front side configured to receive a touch and a back side opposite the front side, a method for transferring a thin film to the sensor panel is disclosed, the method comprising: applying a base layer to a substrate; patterning at least one monolayer film into the base layer, the at least one monolayer film comprising a conductive material configured to detect the touch; adhering a transfer layer on top of the at least one patterned single layer; removing the substrate from the base layer; transferring the combined base layer, at least one patterned single layer, and transfer layer to the back side of the touch-sensitive surface, wherein the base layer is disposed on the back side and the transfer layer is disposed furthest from the back side; and removing the transfer layer from the at least one patterned single layer.

In some embodiments, patterning the at least one monolayer of film comprises: patterning a first monolayer film onto the base layer; placing a dielectric material on top of the first patterned single layer thin film; and patterning a second single layer of thin film on top of the dielectric material, wherein the transfer layer is adhered on top of the second patterned single layer.

In some embodiments, patterning the at least one monolayer of film comprises: patterning a first monolayer film onto the base layer; and patterning a second single layer of thin film on top of the first single layer, wherein the transfer layer is adhered on top of the second patterned single layer.

In some embodiments, a mobile phone is disclosed that includes a touch sensor panel comprising: a touch-sensitive surface having a front side configured to receive a touch and a back side opposite the front side; and a plurality of co-planar single-layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred from the one side of the transfer substrate to the back side of the touch-sensitive surface.

In some embodiments, a digital media player is disclosed that includes a touch sensor panel comprising: a touch-sensitive surface having a front side configured to receive a touch and a back side opposite the front side; and a plurality of co-planar single-layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred from the one side of the transfer substrate to the back side of the touch-sensitive surface.

In some embodiments, a computer is disclosed that includes a touch sensor panel comprising: a touch-sensitive surface having a front side configured to receive a touch and a back side opposite the front side; and a plurality of co-planar single-layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred from the one side of the transfer substrate to the back side of the touch-sensitive surface.

Although the present invention has been fully described in connection with the embodiments thereof 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 included within the scope of the present invention as defined by the appended claims.

Claims (18)

1. A method for transferring a thin film to a substrate, the method comprising:

applying a base layer to a fabrication sheet;

patterning a single layer of thin film on top of the base layer;

adhering a transfer layer on top of the patterned single layer;

removing the fabrication sheet from the base layer;

transferring the combined base layer, patterned single layer and transfer layer to a surface of a substrate, the base layer being in contact with the substrate surface; and

removing the transfer layer from the patterned single layer.

2. The method of claim 1, wherein patterning the single layer of film comprises: a plurality of conductive material portions are formed into a co-planar touch sensor.

3. The method of claim 1, wherein adhering the transfer layer comprises:

depositing a layer of removable adhesive on the patterned single layer; and

placing the transfer layer on top of the removable adhesive layer to adhere to the patterned single layer.

4. The method of claim 1, wherein removing the fabrication sheet comprises: the fabricated wafer is chemically etched.

5. The method of claim 1, wherein transferring the combined base layer, patterned single layer, and transfer layer comprises:

depositing a permanent adhesive on the surface of the substrate; and

placing the base layer on top of the permanent adhesive to adhere the combined base layer, patterned single layer, and transfer layer to the substrate surface.

6. The method of claim 3, wherein the removing of the transfer layer comprises dissolving the removable adhesive in a solvent.

7. The method of claim 1, wherein the base layer comprises an etch stop material.

8. The method of claim 1, wherein the single layer of film comprises a conductive material.

9. The method of claim 8, wherein the conductive material is Indium Tin Oxide (ITO).

10. The method of claim 1, wherein the transfer layer comprises a polymer.

11. The method of claim 1, wherein the substrate layer comprises plastic.

12. The method of claim 11, wherein applying the base layer comprises: the plastic is bonded to the fabrication sheet.

13. The method of claim 11, wherein the removing of the fabrication sheet comprises debinding the plastic to the fabrication sheet.

14. The method of claim 1, wherein the substrate is a cover material for a touch sensitive device.

15. A multi-touch panel, comprising:

a touch-sensitive surface having a front side configured to receive a touch and a back side opposite the front side; and

a plurality of co-planar single-layer touch sensors configured to detect the touch, the touch sensors having been fabricated in a single layer on one side of a transfer substrate and transferred from the one side of the transfer substrate to the back side of the touch-sensitive surface.

16. The multi-touch panel of claim 15, incorporated in a computing system.

17. The multi-touch panel of claim 15, incorporated in a mobile phone.

18. The multi-touch panel of claim 15, incorporated in a digital media player.