PATENT DOCUMENT

Publication Number: US-9128385-B2
Application Number: US-201313970534-A
Country: US
Kind Code: B2

Title: Adaptive photomasks and methods for using the same

Abstract:
The embodiments described herein relate to methods, devices, and systems for masking a substrate using a photomasking process. An adaptive photomask configured to generate a photomasking pattern in accordance with dimensions of a surface feature on substrate is described. The adaptive photomask can be used to create customized photomask patterns for individual substrates. Methods and devices described herein can be used in manufacturing processes where similar parts having slight differences due to built-in tolerances are manufactured. Methods and a devices described herein can also be used in manufacture processes involving masking of three-dimensional portions of a part. A photomasking system that includes a translational mechanism for scanning a substrate surface is described.

Claims:
What is claimed is: 
     
       1. A method for using a configurable aperture to dynamically activate a corresponding portion of a photoresist layer disposed on a surface of a substrate and associated with a feature on the surface of the substrate, the method comprising:
 (a) receiving dimensional data associated with the feature, the dimensional data including data corresponding to a boundary of the feature, wherein the dimensional data is collected by scanning the surface of the substrate using an image capturing device; and 
 (b) adjusting a size and shape of a transmissive portion of the configurable aperture in accordance with the received dimensional data, the transmissive portion allowing energy used to activate a corresponding portion of the photoresist layer to pass. 
 
     
     
       2. The method as recited in  claim 1 , wherein the adjusted size and shape of the transmissive portion corresponds with the boundary of the feature. 
     
     
       3. The method as recited in  claim 1 , wherein scanning the surface of the substrate includes moving the image capturing device in accordance with a scan path along the surface of the substrate. 
     
     
       4. The method as recited in  claim 1 , wherein the energy is in the form of light. 
     
     
       5. The method as recited in  claim 1 , wherein the configurable aperture is configured to move along the surface of the substrate. 
     
     
       6. The method as recited in  claim 5 , wherein the shape and size of the transmissive portion is adjusted as the configurable aperture moves along the surface of the substrate. 
     
     
       7. The method as recited in  claim 5 , wherein a translation mechanism moves the configurable aperture along the surface of the substrate. 
     
     
       8. The method as recited in  claim 1 , wherein the configurable aperture has an opaque portion that prevents energy from passing to the photoresist layer, wherein adjusting the size and shape of the transmissive portion comprises adjusting the opaque portion of the configurable aperture. 
     
     
       9. The method as recited in  claim 8 , wherein adjusting the opaque portion of the configurable aperture comprises darkening a portion of pixels of a pixelated medium. 
     
     
       10. The method as recited in  claim 1 , wherein the feature is a chamfered edge of the substrate and wherein the boundary corresponds to a boundary between adjacent surfaces of the substrate along the chamfered edge. 
     
     
       11. A method for using an adaptive photomask to dynamically activate a portion of a first photoresist layer disposed on a first part and a second photoresist layer disposed on a second part, the first part having a first surface feature and the second part having a second surface feature, the method comprising:
 receiving a first set of dimensional data associated with the first feature, the first set of dimensional data including data corresponding to a first feature boundary of the first feature, wherein the first set of dimensional data is collected by scanning a surface of the first part using an image capturing device; 
 adjusting a size and shape of a transmissive portion of the adaptive photomask in accordance with the received first set of dimensional data, the transmissive portion allowing energy to pass therethrough, activating a portion of the first photoresist layer corresponding to the first feature; 
 receiving a second set of dimensional data associated with the second feature, the second set of dimensional data including data corresponding to a second feature boundary of the second feature, wherein the second set of dimensional data is different than the first set of dimensional data, wherein the second set of dimensional data is collected by scanning a surface of the second part using the image capturing device; and 
 adjusting a size and shape of the transmissive portion of the adaptive photomask in accordance with the received second set of dimensional data, the transmissive portion allowing used to pass therethrough, activating a portion of the second photoresist layer corresponding to the second feature. 
 
     
     
       12. The method as recited in  claim 11 , wherein scanning the surface of the first part includes moving the image capturing device in accordance with a scan path along the surface of the first part, and scanning the surface of the second part includes moving the image capturing device in accordance with the scan path along the surface of the second part. 
     
     
       13. The method as recited in  claim 11 , wherein the energy is in the form of light. 
     
     
       14. The method as recited in  claim 11 , wherein the adaptive photomask is configured to move along the surface of the first part and the surface of the second part. 
     
     
       15. The method as recited in  claim 14 , wherein the shape and size of the transmissive portion is adjusted as the adaptive photomask moves along the surface of the first part or the surface of the second part. 
     
     
       16. The method as recited in  claim 11 , further comprising:
 after receiving the first set of dimensional data, aligning the transmissive portion with the first feature; and 
 after receiving the second set of dimensional data, aligning the transmissive portion with the second feature. 
 
     
     
       17. The method as recited in  claim 11 , wherein the first set of dimensional data includes three dimensional data related to three dimensional aspects of the first part and the second set of dimensional data includes three dimensional data related to three dimensional aspects of the second part. 
     
     
       18. An adaptive photomask system configured to dynamically generate a photomask pattern based on a feature on a surface of a substrate, the adaptive photomask system comprising:
 an image capturing device configured to scan the surface of the substrate and collect dimensional data related to a boundary of the feature; 
 an adaptive photomask configured to adjust a changeable medium of the adaptive photomask based on the dimensional data, the changeable medium comprising selectively transmissive elements, wherein, when in a transmissive state, the selectively transmissive elements combine to from a transmissive portion that allows light to pass therethrough and activate a corresponding portion of a photoresist layer disposed on the surface of the substrate. 
 
     
     
       19. The adaptive photomask system as recited in  claim 18 , wherein the changeable medium is pixelated with each pixel corresponding to a selectively transparent element. 
     
     
       20. The adaptive photomask system recited in  claim 18 , further comprising:
 a translational mechanism configured to move the image capturing device in accordance with a scan path along the surface of the substrate. 
 
     
     
       21. The adaptive photomask system as recited in  claim 20 , wherein the translational mechanism is configured to translate the image capturing device in accordance with the scan path along a three dimensional portion of the substrate. 
     
     
       22. The adaptive photomask as recited in  claim 18 , wherein the image capturing device and the adaptive photomask are configured to move along the surface of the substrate, wherein a shape of the transmissive portion transforms as the image capturing device and adaptive photomask move along the surface of the substrate.

Description:
FIELD OF THE DESCRIBED EMBODIMENTS 
     The described embodiments relate generally to photomasks and photomasking techniques used in the manufacture of consumer products. More specifically, photomasks and photomasking techniques that accommodate for tolerances accumulated during manufacture of consumer products are described. 
     BACKGROUND 
     Photomasks are generally opaque plates with holes or transparencies that allow light to shine through in a defined pattern. They are commonly used in photoengraving and surface finishing processes to transfer a geometric pattern of light onto a light-sensitive chemical photoresist on a substrate surface. The substrate is then chemically treated to remove portions of the photoresist either exposed to light or not exposed to light, depending on the type of photoresist that is used. The patterned photoresist remaining on the surface of the substrate can then act as a mask during any of a number of surface treatment procedures, such as deposition, etching or blasting processes. After the photoresist is removed, the substrate surface is left with a pattern of treated and untreated regions. 
     In some cases, the substrate surfaces can include one or more surface features, such as designs and inlays. In some cases the features can be positioned on corners and edges. These surface features have borders that define the surface features. In a manufacturing environment where multiple similar parts are produced, the dimensions of the features can vary from part to part due to built-in tolerances of the manufacturing process. However, in traditional photomasking techniques the pattern imprinted on the photomask is fixed and does not accommodate any dimensional differenced of the features due to the manufacturing tolerances. This can ultimately lead to parts with surfaces having patterns of treated and untreated regions that mismatch the borders of the surface features. These mismatched borders can be noticeably cosmetically unappealing, especially if they are on exterior surfaces of a consumer product. 
     SUMMARY 
     This paper describes various embodiments that relate to photomasking a substrate. The photomasking procedure can take place prior to a photoengraving, photoetching or other surface treatment procedure. Methods described are useful for providing custom photomask patterns for a single part or a series of parts manufactured in a manufacturing line. 
     According to one embodiment, a method for using a configurable aperture to dynamically activate a corresponding portion of a photoresist layer disposed on a surface of a substrate and associated with at least one surface feature is described. The method involves receiving a set of dimensional data associated with the at least one surface feature. The dimensional data includes data corresponding to a boundary of the at least one surface feature. The method also involves adjusting a size and shape of a transmissive portion of the configurable aperture in accordance with the received dimensional data. The transmissive portion allows energy used to activate the corresponding portion of the photoresist layer to pass. 
     According to another embodiment, a method for using an adaptive photomask to dynamically activate a portion of a first photoresist layer disposed on a first part and a second photoresist layer disposed on a second part is described. The first part has a first surface feature and the second part has a second surface feature. The method includes receiving a first set of dimensional data associated with the first feature. The first set of dimensional data includes data corresponding to a first feature boundary of the first feature. The method also includes adjusting a size and shape of a transmissive portion of the adaptive photomask in accordance with the received first set of dimensional data. The transmissive portion allows energy used to activate a portion of the photoresist layer corresponding to the first feature to pass. The method also includes receiving a second set of dimensional data associated with the second feature. The second set of dimensional data including data corresponding to a second feature boundary of the second feature, where the second set of dimensional data is different than the first set of dimensional data. The method also includes adjusting a size and shape of the transmissive portion of the adaptive photomask in accordance with the received second set of dimensional data. The transmissive portion allows energy used to activate a portion of the photoresist layer corresponding to the second feature to pass. 
     According to an additional embodiment, an adaptive photomask configured to dynamically generate a number of different photomask patterns based on a number of features on at least one substrate surface is described. The adaptive photomask includes a changeable medium having a number of selectively transmissive elements. When in a transmissive state, each of the selectively transmissive elements allows light to passes therethrough to activate a corresponding portion of a photoresist layer disposed on the at least one substrate. The changeable medium is configured to receive a first set of dimensional data associated with a boundary of a first surface feature and a second set of dimensional data associated with a boundary of second surface feature, where the first set is different from the second set. The changeable medium is also configured to form a first photomask pattern by causing a first group of the selectively transmissive elements to become transmissive in accordance with the received first set of dimensional data. The changeable medium is also configured to form a second photomask pattern different from the first pattern by causing a second group of selectively transmissive elements to become transmissive in accordance with the received second set of dimensional data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The described embodiments and the advantages thereof may be better understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that may be made to the described embodiments by one skilled in the art without departing from the spirit and scope of the described embodiments. 
         FIGS. 1A-1F  illustrate perspective views of a part having a surface feature undergoing photoresist, photomasking, and texturing processes. 
         FIGS. 2A and 2B  illustrate top views of an adaptive photomask with two different parts. 
         FIG. 3  illustrates a perspective view of a part having a chamfered edge and textured surfaces. 
         FIGS. 4A-4C  illustrate top views of an adaptive photomask used in a photomasking process for a chamfered edge of a part. 
         FIG. 5  illustrates a side view of a part having a surface feature located at a curved edge of a part. 
         FIGS. 6A-6C  illustrate various views of a photomasking system that includes an adaptive photomask. 
         FIG. 7  illustrates a flowchart indicating a photomasking process using an adaptive photomask. 
         FIG. 8  illustrates a block diagram of an electronic device suitable for use with an adaptive photomasking system. 
     
    
    
     DETAILED DESCRIPTION OF SELECTED EMBODIMENTS 
     The following disclosure describes various embodiments of photomasks and methods for using photomasks. Certain details are set forth in the following description and Figures to provide a thorough understanding of various embodiments of the present technology. Moreover, various features, structures, and/or characteristics of the present technology can be combined in other suitable structures and environments. In other instances, well-known structures, materials, operations, and/or systems are not shown or described in detail in the following disclosure to avoid unnecessarily obscuring the description of the various embodiments of the technology. Those of ordinary skill in the art will recognize, however, that the present technology can be practiced without one or more of the details set forth herein, or with other structures, methods, components, and so forth. 
     The embodiments described herein relate to methods, systems, and devices for masking portions of a surface of a substrate. The methods involve the use of photomasks, which generally have patterns of opaque and transparent regions corresponding to a pattern of light or other energy that a photoresist layer disposed on a substrate surface will be exposed to. The opaque regions allow light, typically ultraviolet (UV) light, to pass through to the photoresist layer. The opaque regions substantially block the passage of light from reaching the photoresist layer. In described embodiments, an adaptive photomask capable of generating a custom pattern of opaque and transparent portions is described. 
       FIGS. 1A-1F  illustrate prospective views of part  100  undergoing a photomasking process, as well as a texturing process.  FIG. 1A  shows part  100  with surface  102  having a surface feature  106  within surrounding surface portion  104 . Boundary  108  defines the dimensions of surface feature  106 , including its size, shape and position within surrounding surface portion  104 . In some embodiments, surface feature  106  is a design, such as an inlay. In some embodiments, surface feature  106  is made of a different material than surrounding surface portion  104 . For example, surface feature  106  can be made of a plastic or ceramic material and surrounding surface portion  104  can be made of a metal material. In other embodiments, surface feature  106  and surrounding surface portion  104  are made of the same material. In some embodiments, surface feature  106  rises above or recesses within surrounding surface portion  104 . 
     The photomasking process described herein can be used to treat one or both of surrounding surface portion  104  and surface feature  106  to have different surface qualities. To accomplish different surface qualities, one of surrounding surface portion  104  and surface feature  106  is masked using a photoresist material to protect it from exposure to a particular surface treatment process. In the embodiments shown in  FIGS. 1A-1F , the surface feature  106  is masked while surrounding surface portion  104  is unmasked during a texturing process. In one embodiment, prior to photomasking, surrounding surface portion  104  and surface feature  106  are treated to have a certain surface quality. For example, surrounding surface portion  104  and surface feature  106  can be polished to have a shiny finish. 
     At  FIG. 1B , photoresist  110  is applied over part  100  covering both surrounding surface portion  104  and surface feature  106 . In some embodiments, photoresist  110  is a light sensitive polymer material that can be initially applied in liquid form. In some embodiments, photoresist  110  is sensitive to other forms of energy such as energy from an e-beam. Photoresist  110  can be applied using any suitable technique such as spin-on or spray-on techniques to form a thin layer of photoresist material. In one embodiment, photoresist  110  is substantially transparent or translucent such that boundary  108  is visible from a top surface of part  100 . 
     At  FIG. 1C , photomask  112  is positioned a distance above photoresist  110  and part  100 . Photomask  112  has a transmissive portion  114  having a shape corresponding to surface feature  106 . During a photoresist activating or curing process, light passes through transmissive portion  114  to expose and activate the portion of photoresist  110  corresponding to the shape of surface feature  106 . Transmissive portion  114  can be in the form of an opening or can be in the form of a transparent portion of photomask  112 . Opaque portion  111  of photomask  112  substantially blocks the passage of light or other energy from reaching photoresist  110  and part  100 . In some embodiments, photomask  112  is designed to block and allow passage of UV light. At  FIG. 1D , photoresist  110  is chemically treated to remove portions of photoresist  110  covering surrounding surface portion  104 . Since photoresist  110  covering surface feature  106  has been activated, this portion remains after the chemical treatment. At  FIG. 1E , part  100  undergoes a texturing process, such as an etching or blasting process. As a result, surrounding surface portion  104  takes on a different surface quality in accordance with the surface texturing process. Surface feature  106  is covered by and protected by photoresist  110 , and therefore is not exposed to the surface treatment. At  FIG. 1F , photoresist  110  is removed leaving surrounding surface portion  104  and surface feature  106  with different surface qualities. 
     Embodiments described herein relate to photomasks, such as photomask  112 , and methods for using photomasks. In embodiments described herein, the patterns of transmissive and opaque regions within the photomasks can be customized to have a shape in accordance with particular features on the substrate. The embodiments described are well suited for a manufacturing environment where multiple similar parts are created. The photomasks can be customized to accommodate for differences between individual parts due to manufacturing tolerances. For example, during the manufacture of part  100 , the dimensions of surface feature  106  can be different than a corresponding surface feature of another part using the same manufacturing process. These differences can be due to tolerances built into the manufacturing process. Thus, the dimensions of feature boundary  108  can differ slightly from part to part. Traditional photomasking techniques involve using a photomask having a fixed pattern of transparent and opaque regions. The use of a fixed pattern photomask can result in variability of the position of boundary of the textured portion with respect to the feature boundary. In the case of part  100 , for example, regions of surrounding surface portion  104  can become masked, and thereby not be exposed to the texturing process, and regions of surface feature  106  can be unmasked, and thereby be exposed to the texturing process. The result is the boundary of the textured portion does not overlap consistently with feature boundary  108 . If surface feature  106  is a feature that has an irregular or non-linear geometry, such as a spline curve, it manufacturing tolerances can be greater, leading to even more dimensional variability from part to part. 
     Embodiments herein describe an adaptive photomask that can be used to create a customized photomask pattern for each part. The customized photomask pattern can be generated in accordance with existing surface features of the part. For example, referring back to  FIG. 1 , an adaptive photomask can be used to create a customized photomask pattern to form textured surfaces on part  100  with boundaries that match with corresponding feature boundaries  108 . Since the photomask patterns are customized for each part, the photomask takes into account part-to-part differences associated with built-in tolerances of the manufacturing process. The result is consistently aligned and cosmically appealing boundaries between masked and unmasked portion of the part. 
       FIGS. 2A and 2B  show top views of adaptive photomask  200 , along with two different parts  210  and  230 , in accordance with described embodiments. At  FIG. 2A , adaptive photomask  200  is at a first state for photomasking first part  210 . At  FIG. 2B , adaptive photomask  200  is at a second state for photomasking second part  230 . First part  210  and second part  230  can be two similar parts produced in a manufacturing process. First part  210  and second part  230  have similar but differently shaped features  212  and  232  within surrounding surfaces  214  and  234 , respectively. Feature boundaries  216  and  236  define the shapes and sizes of features  212  and  232 , respectively. In one embodiment, features  212  and  232  are made of the same material as surrounding surfaces  214  and  234 , respectively. In one embodiment, features  212  and  232  are made of the different material than surrounding surfaces  214  and  234 , respectively. Features  212  and  232  can be recessed, protruded or flush with surrounding surfaces  214  and  234 , respectively. 
     As shown, feature  212  of part  210  has a slightly different dimensions compared to feature  232  of part  230 . These differences can be due to manufacturing variations, i.e. manufacturing or engineering tolerances. At  FIG. 2A , photomask  200  is at a first state with transmissive portion  202  corresponding to feature  212  of part  210 . At  FIG. 2B , photomask  200  is at a second state with transmissive portion  222  corresponding to feature  232  of part  230 . Transmissive portions  202  and  222  of photomask  200  are configured to allow energy such as light to pass therethrough and opaque portions  204  and  224  are configured to substantially block the passage of energy such as light. Photomask feature boundaries  206  and  226  define the shapes and sizes of transparent portions  202  and  222 , respectively. As described above with reference to  FIGS. 1A-1F , energy passing through transparent portions  202  and  222  can impinge on layers of photoresist (not shown) formed over parts  210  and  230 . Note that photomask  200  can be designed to block and let through any suitable wavelengths of light during a photomasking process. In some embodiments, photomask  200  is designed to block and let through UV wavelengths of light. The unexposed photoresist corresponding to surrounding surfaces  214  and  234  can then be removed, leaving a photoresist mask over features  212  and  232 . Note that  FIGS. 2A and 2B  are presented as examples of a photomask in accordance with described embodiments and are not meant to represent all possible embodiments. For instance, other embodiments can include photomasks where the transparent portions and opaque portions are reversed. In other embodiments, the photomasks can include multiple transparent portions corresponding to multiple features on a part. 
     As shown in  FIGS. 2A and 2B , transparent portions  202  and  222  have slightly different shapes in order to accurately correspond to slightly different shapes of features  212  and  232  of parts  210  and  230 , respectively. In a sense, adaptive photomask  200  can act as a configurable aperture that dynamically adjusts to different sizes and shapes of different features  212  and  232 . That is, photomask  200  is adaptive in that it can provide a customized pattern of transmissive and opaque portions. In this way, photomask  200  can accommodate the slightly different dimensions of feature  212  of part  210  and feature  232  of part  230 . Photomask  200  can be any suitable photomask capable of providing changeable opaque and transmissive portions. In some embodiments, photomask  200  includes a changeable medium made of substantially transparent material, such as transparent glass or plastic, which has a number of selectively transmissive elements. Each of the selectively transmissive elements can be in a transmissive state that allows energy to pass through or an opaque state that blocks energy from passing through. In some embodiments, the selective transmissive elements can transition between a transmissive state and an opaque state in response to an applied voltage. In some embodiments, the changeable medium is pixilated with each pixel corresponding to a selectively transparent element. Photomask  200  can be in the form of a pane or a film, or a composite structure made of a number of stacked layers or films. In some embodiments, photomask  200  includes organic light emitting diodes (OLED) like materials that have portions that change opacity in response to an applied voltage. In some embodiments, photomask  200  includes an electrochromic glass, sometimes referred to as smart glass. Portions of the electrochromic glass can change transmission of light when voltage is applied. In one embodiment, the applied voltage can cause particles, such as suspended rod-like particles or liquid crystals, in the electrochromic glass to arrange such that substantially none of the photoresist activating wavelengths of light passes through in opaque portions of the glass. 
     In some cases, the features can include three-dimensional features of a part.  FIG. 3  shows a perspective view of part  300  having a chamfered edge  302 . As shown, chamfered edge  302  includes flat surface  304  and curved surfaces  306  and  308 . Feature boundaries  318  define the borders between chamfered edge  302  and surrounding surfaces  312  and  314 . Feature boundaries  320  define the borders between flat surface  304  and curved surface  306  and  308  within chamfered edge  302 . Surfaces  312  and  314  are textured surfaces formed by photomasking and texturing techniques similar to those described above for part  100 . Surfaces  304 ,  306  and  308  are masked prior to the texturing process. Because of the three-dimensional characteristics of chamfered edge  302 , there can be dimensional variability from part to part in the manufacture of multiple parts similar to part  300 . For example, the width of flat portion  304  and curved portions  306  and  308  can vary slightly from part to part. In some cases, the width of portion  304  and curved portions  306  and  308  can vary within part  300 . Thus, traditional techniques of using a photomask having a fixed pattern can result in variability of where boundaries of textured surfaces  312  and  314  begin and end. 
       FIGS. 4A-4C  show top views of adaptive photomask  400  that can be used in a photomasking process for chamfered edge  302  of part  300  of  FIG. 3 . Photomask  400  is configured to change states while being moved along chamfered edge  302 . At  FIG. 4A , photomask  400  is at a first state for exposing a straight edge portion of chamfered edge  302  to light. In the first state, photomask  400  includes transparent portion  402 , configured to allow light to pass therethrough, and opaque portions  404 , configured to block passage of light. Photomask feature boundaries  406  define the surface area of part  300  that is exposed to light. Note that photomask  400  can be designed to block and let through any suitable wavelengths of light during a photomasking process. In some embodiments, photomask  400  is configured to block and let through UV wavelengths of light. 
     At  FIG. 4B , photomask  400  has been moved to a curved portion of chamfered edge  302  and is at a second state for exposing part  300  to light. In the second state, photomask  400  includes transparent portion  408 , configured to allow light to pass therethrough, and opaque portions  410 , configured to block passage of light. Photomask feature boundaries  412  define the surface area of part  300  that is exposed to light. At  FIG. 4C , photomask  400  has been moved to another straight portion of chamfered edge and is at a third state for exposing part  300  to light. In the third state, photomask  400  includes transparent portion  414 , configured to allow light to pass therethrough, and opaque portions  416 , configured to block passage of light. Photomask feature boundaries  418  define the surface area of part  300  that is exposed to light. 
     Photomask feature boundaries  406 ,  412  and  418  can be configured to align with feature boundaries  318  along chamfered edge  302  of part  300 . In this way, photoresist that covers curved portions  306  and  308  and straight portion  304  will be exposed to light and remain after a photoresist chemical treatment process. Part  300  can then undergo a texturing process to form textured surfaces on surfaces  312  and  314 . If dimensions of feature boundaries  318  vary along chamfered edge  302 , photomask feature boundaries  406 ,  412  and  418  can be adjusted accordingly. In this way, the boundaries of the textured surfaces  312  and  314  can be aligned precisely with feature boundaries  318 . In alternative embodiments, the photomask feature boundaries  406 ,  412  and  418  can be chosen to align with other features of part  300 . For example, feature boundaries  320  can be used as a basis of forming photomask feature boundaries  406 ,  412  and  418 . In these embodiments, only flat portion  304  of chamfered edge  302  can be masked during the texturing process, thereby forming textured surfaces on curved surfaces  306  and  308 , as well as surrounding surfaces  312  and  314 . 
     In some cases, a part can include a feature that exists on a three-dimensional surface.  FIG. 5  shows a side view of part  500  having feature  506  and surrounding surface  504 . In some embodiments, feature  506  and surrounding surface  504  are made of different materials. In one embodiment, feature  506  is made of a plastic or ceramic material and surrounding surface  504  is made of a metal material. In some embodiments, surrounding surface  504  has is textured from a texturing process and feature  506  has a smooth and polished surface. The combination of textured and smooth surfaces can be producing using a photomasking process similar to that described above with reference to  FIGS. 1-4 . As shown, feature  506  is located along edge  502  of part  500  and is define by feature boundary  508 . Since feature  506  is located at a curved surface of part  500 , the dimensions of boundary  508  can substantially vary from part to part due to manufacturing tolerance. Thus, traditional photomasking techniques using a fixed photomask pattern can result in parts having a textured surface boundary that does not align with feature boundary  508 . The adaptive photomasks and methods described herein allow for precise alignment of the textured surface boundary and feature boundary  508 . 
     According to some embodiments, the adaptive photomask is part of a photomasking system, which can include one or more image capturing devices for capturing images of the surface of the part. In some embodiments, the photomasking system also includes a translational mechanism configured to move the photomasking system along a surface of the part.  FIGS. 6A-6C  show various views of photomasking system  600  in accordance with described embodiments.  FIG. 6A  shows a front view of adaptive photomasking system  600 , which includes a photomasking unit  601 . Photomasking unit  601  can include adaptive photomask  602 , image capturing device  604 , and light source  606 . In some embodiments, light source  606  is a UV light source configured to generate UV wavelengths of light. Light  614  from light source  606  can shine through transparent portion  612  of adaptive photomask  602  in a pattern of light  616  onto a surface of part  608 . Part  608  includes feature  610  that has feature boundary  624 . Image capturing device  604  is configured to capture image data associated with a surface of part  608 , including feature boundary  624  of feature  610 . Image capturing device  604  can be any suitable device capable of capturing image data associated with feature  610 . In some embodiments, image capturing device  604  can include a charge-coupled device (CCD) image sensor or a complementary metal-oxide-semiconductor (CMOS) image sensor. Image capturing device  604  can capture the image and convert it into electrical signals, which can then be used to create a corresponding pattern of opaque and transparent portions on adaptive photomask  602 . Image capturing device  604  can also include a memory storage device for storing the image data, including dimensional data associated with feature boundary  624 . 
     During a photomasking process, adaptive photomasking unit  601  can move along a surface of part  608  using a translational mechanism. The translational mechanism can include a motor mechanism (not shown) that moves photomasking unit  601  along track  622 . Photomasking unit  601  and track  622  are positioned relative to part  608  such that photomasking unit  601  follows a scan path above a surface of part  608 . In some embodiments, photomasking unit  601  continuously moves or scans above a surface of part  608 . In other embodiments, photomasking unit  601  stops at certain sections, such as those sections that have features, to collect image data and expose photoresist  611  to light. In some embodiments, adaptive photomasking unit  601  includes proximity sensor  618 , which can detect and collect proximity data regarding the proximity of the surface of part  608  during movement along track  622 . The proximity data can be used in conjunction with the translational mechanism to adjust movement of photomasking unit  601 . In some embodiments, adaptive photomasking unit  601  includes linear actuator  620 , which can direct linear translational movement of photomasking unit  601  along track  622 . 
     In some embodiments, adaptive photomasking unit  601  is scanned across the surface of part  608  at least two times during a photomasking process. During the first scan, photomasking unit  601  moves over the surface of part  608  while image capturing device  604  captures and stores image data. Next, the surface of part  608  is covered with photoresist  611 . During the second scan, photomasking unit  601  moves over the surface of part  608  along the same path as the first scan during an exposure process. During the exposure process, adaptive photomask  602  produces a custom pattern of opaque and transparent  612  portions based on the image data while light source  606  shines light through transparent portion  612 . As a result, portions of photoresist  611  that are positioned over feature  610  and have the same dimensions as feature boundary  624  are exposed to light. In this way, precise masking of feature  610  can be accomplished. 
     In an alternative embodiment, adaptive photomasking unit  601  is scanned across the surface of part  608  one time during a photomasking process. That is, the image capturing and light exposure occur during one scan. In these embodiments, photoresist  611  covers part  608  prior to the scan. The photoresist can be sufficiently transparent or semi-transparent such that image data associated with feature  610  can be detected by image capturing device  604 . During the scan, image capturing device  604  captures the image data, which is transferred to adaptive photomask  602 . Adaptive photomask  602  produces a custom pattern of opaque and transparent  612  portions based on the image data while light source  606  shines light through transparent portion  612 . As a result, portions of photoresist  611  that are positioned over feature  610  and have the same dimensions as feature boundary  624  are exposed to light. In this way, precise masking of feature  610  can be accomplished in one scan of photomasking unit  601 . 
       FIG. 6B  shows a side view of photomasking unit  601  exposing a chamfered edge  628  of part  608 . In some embodiments, shields  630  can be positioned proximate to photomasking unit  601  to prevent stray light from impinging on other surfaces of part  608 .  FIG. 6C  shows a top view of adaptive photomasking system  600 . As shown, photomasking unit  601  can be situated on track  622  to follow a surface of part  608  during a scanning operation. In one embodiment, track  622  and photomasking unit  601  can be configured to follow a perimeter surface of  608 . Motor mechanism  626  can move adaptive photomasking system  600  along track  622 . 
       FIG. 7  shows flowchart  700  indicating a photomasking process in accordance with described embodiments. At  702 , reference data (e.g., dimensional data) associated with a feature on a surface of a part is captured. The reference data can be captured using an image capturing device. The image capturing device can include a CCD or CMOS image sensor. The reference data can be stored on a storage medium of the image capturing device. In some embodiments, the part has an overlaying film of photoresist when the reference data is captured. In other embodiments, the reference data is captured prior to forming the photoresist layer on surface of the part. At  704 , a pattern based on the reference data is generated on an adaptive photomask. The pattern can be displayed as a digitized image, such a pattern of darkened pixels of a pixilated transparent material. That is, a portion of the pixels can be darkened to substantially block passage of light in response to receiving the reference data. In some embodiment, the reference data can be sent by the image capturing device and received by a processor associated with the adaptive photomask that instructs the adaptive photomask to generate the digitized pattern. At  706 , a portion of photoresist corresponding to the pattern is exposed to light by shining light through transparent portions of the pattern of the adaptive photomask. If a negative photoresist is used, those portions exposed to light will remain on the substrate surface after a subsequent photoresist development process. If a positive photoresist is used, those portions exposed to light will be removed from the substrate surface after a subsequent photoresist development process. As described above with reference to  FIGS. 6A-6C , a photomasking system that includes a translational mechanism can be used to displace the image capturing device and move the adaptive photomask to a position directly over the portion of the part for the light exposure. 
     At  708 , a determination is made as to whether the patterning of the photoresist is complete. Typically, patterning the photoresist is complete when those portions of the photoresist corresponding to the complete pattern of the adaptive photomask have been exposed to light. If it is determined that the patterning is complete, at  712  the photoresist is developed to remove portions of the photoresist that are not used for masking. Those portions of the photoresist remaining have a pattern corresponding to the pattern of the adaptive photomask. The part can then undergo any of a number of surface treatments to provide a surface quality to unmasked portions of the part. If it is determined that the patterning of the photoresist is not complete, at  710  the adaptive photomask is traversed to the next section of the part. Then, at  706  the next section of the part is exposed to another portion of the pattern of light. Steps  706 ,  708  and  710  are repeated until the patterning of the photoresist is complete. 
     The described embodiments can be embodied as computer readable code on a non-transitory computer readable medium for controlling manufacturing operations or as computer readable code on a non-transitory computer readable medium for controlling a manufacturing line.  FIG. 8  is a block diagram of electronic device  800  suitable for controlling some of the processes in the described embodiment. Electronic device  800  illustrates circuitry of a representative computing device that can be used during one or more procedures in the photomasking processes described herein. Electronic device  800  includes a processor  802  that pertains to a microprocessor or controller for controlling the overall operation of electronic device  800 . Electronic device  800  contains instruction data pertaining to manufacturing instructions in a file system  804  and a cache  806 . File system  804  is, typically, a storage disk or a plurality of disks. File system  804  typically provides high capacity storage capability for the electronic device  800 . However, since the access time to the file system  804  can be relatively slow, electronic device  800  can also include a cache  806 . Cache  806  can be, for example, Random-Access Memory (RAM) provided by semiconductor memory. The relative access time to cache  806  can be substantially shorter than for file system  804 . However, cache  806  may not have the large storage capacity of the file system  804 . Further, file system  804 , when active, can consume more power than cache  806 . In some embodiments, electronic device  800  is a portable device powered by battery  824 . Electronic device  800  can also include a RAM  820  and/or Read-Only Memory (ROM)  822 . ROM  822  can store programs, utilities or processes to be executed in a non-volatile manner. RAM  820  can provide volatile data storage, such as for cache  806 . 
     Electronic device  800  can include user input device  808  that allows a user of electronic device  800  to interact with electronic device  800 . User input device  808  can take a variety of forms, such as a button, keypad, dial, touch screen, audio input interface, visual/image capture input interface, input in the form of sensor data, etc. Still further, electronic device  800  can include display  810  (screen display) that can be controlled by the processor  802  to display information to the user. Data bus  816  can facilitate data transfer between at least file system  804 , cache  806 , processor  802 , and coder/decoder (CODEC)  813 . CODEC  813  can be used to decode and play a plurality of media items from file system  804  that can correspond to certain activities taking place during a particular manufacturing process. Processor  802 , upon a certain manufacturing event occurring, can supply media data (e.g., audio file) for a particular media item to a CODEC  813 . CODEC  813  can then produce analog output signals for a speaker  814 . Speaker  814  can be a speaker internal to electronic device  800  or external to electronic device  800 . For example, headphones or earphones that connect to the electronic device  800  would be considered an external speaker. 
     Electronic device  800  can also include network/bus interface  811  that couples to data link  812 . Data link  812  can allow electronic device  800  to couple to a host computer or to accessory devices. Data link  812  can be provided over a wired connection or a wireless connection. In the case of a wireless connection, network/bus interface  811  can include a wireless transceiver. The media items (media assets) can pertain to one or more different types of media content. In one embodiment, the media items are audio tracks (e.g., songs, audio books, and podcasts). In another embodiment, the media items are images (e.g., photos). However, in other embodiments, the media items can be any combination of audio, graphical or visual content. Sensor  826  can take the form of circuitry for detecting any number of stimuli. For example, sensor  826  can include any number of sensors for monitoring a manufacturing operation such as for example a Hall Effect sensor responsive to external magnetic field, an audio sensor, a light sensor such as a photometer, and so on. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20130819
Publication Date: 20150908
Grant Date: 20150908
Priority Date: 20130819
Inventors: TAN NAPTHANEAL YUEN
Assignee: APPLE INC
CPC Classifications: [{"code": "G03F1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F7/70291", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F7/2045", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/50", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03F7/2045", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/56", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03F1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/50", "inventive": true, "first": true, "tree": "[]"}, {"code": "G03F7/2045", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F7/70291", "inventive": true, "first": false, "tree": "[]"}, {"code": "G03F1/50", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 52466625