CN118119894A - EUV lithography using polymer crystal-based reticle - Google Patents

Abstract

Embodiments of the present disclosure relate to a photomask. The photomask may include: a substrate; and one or more pixel units formed on the substrate. Each pixel unit may include: at least one polymer crystal element configured to interact with Extreme Ultraviolet (EUV) light based on an orientation of the polymer crystal element; and a plurality of electrodes configured to control an orientation of the polymer crystal element by applying a voltage across the polymer crystal element. Each pixel cell is independently controlled by a respective one of the plurality of electrodes, and the one or more pixel cells generate a pattern for lithography when exposed to the EUV light.

Description

EUV lithography using polymer crystal-based reticle

Technical Field

The present disclosure relates generally to semiconductor fabrication, and in particular to semiconductor fabrication using extreme ultraviolet (Extreme Ultraviolet, EUV) lithography.

Background

EUV photomasks operate by reflecting light. A typical EUV photomask (also referred to as a mask or reticle) is a complex stack of multiple layers of silicon and molybdenum. Photomasks are critical to the creation of transistor and metal trace patterns on wafers (e.g., silicon/III-V wafers). Advanced technology nodes such as 14nm or 7nm may require about 50 to 100 photomasks, where the cost of each photomask is typically between $35 ten thousand ($350 k) and $75 ten thousand ($750 k). Therefore, from the viewpoint of technical development, a large amount of capital is required to optimize the manufacturing process before large-scale production is entered. Optical proximity correction (Optical Proximity Correction, OPC) is a key aspect of photomask development that optimizes patterns on the mask according to optical wavelength, diffraction compensation, etc. If not done properly, the mask may need to be redesigned, and the cost and time spent designing and manufacturing a new mask may be very high.

Disclosure of Invention

Embodiments of the present invention present a polymer crystal based photomask that allows a user to optimize OPC (or other pattern related problems) during a photolithography process. The photomask may be modified in situ depending on the OPC, the angle of EUV light used, and the type of pattern to be transferred on the wafer using photoresist.

In one aspect, the present disclosure relates to a photomask for EUV lithography. The photomask may include: a substrate; and one or more pixel units formed on the substrate. Each pixel unit may include: at least one polymer crystal element configured to interact with Extreme Ultraviolet (EUV) light based on an orientation of the polymer crystal element; and a plurality of electrodes configured to control an orientation of the polymer crystal element by applying a voltage across the polymer crystal element. Each pixel cell is independently controlled by a respective one of the plurality of electrodes, and the one or more pixel cells generate a pattern for lithography when exposed to the EUV light.

In some embodiments, the plurality of electrodes may set the polymer crystal element in a first orientation by applying a first voltage, and the polymer crystal element is configured to absorb the EUV light when in the first orientation.

In some embodiments, the plurality of electrodes may set the polymer crystal element in a second orientation by applying a second voltage, and the polymer crystal element is configured to reflect the EUV light when in the second orientation.

In some embodiments, the photomask may further include a thin film layer covering the one or more pixel cells to prevent contamination.

In some embodiments, the photomask may further include an active layer between the substrate and the one or more pixel cells, wherein the active layer includes circuitry connected to the plurality of electrodes.

In some embodiments, the polymeric crystalline element may be a cholesteric liquid crystal (Cholesteric Liquid Crystal, CLC) material.

In some embodiments, the photomask may further include a back plate configured to cool the one or more pixel cells.

In some embodiments, the photomask may further include one or more slider rails and a motor configured to rotate the photomask.

In some embodiments, the photomask further includes multiple layers of pixel cells stacked on the substrate, each layer of pixel cells configured to interact with the EUV light at a different wavelength.

In some embodiments, the photomask may further include a temperature control component for monitoring and controlling the temperature of the photomask.

In another aspect, the present disclosure relates to a method for EUV lithography. The method may include: receiving an instruction comprising a target photomask design; generating a mask pattern adjusted by OPC based on the photomask design; determining a pixel pattern based on the OPC-adjusted mask pattern; and configuring one or more pixel units of a polymer crystal-based photomask based on the determined pixel pattern. Each of the one or more pixel units may include: at least one polymer crystal element configured to interact with Extreme Ultraviolet (EUV) light based on an orientation of the polymer crystal element; and a plurality of electrodes configured to control an orientation of the polymer crystal element by applying a voltage across the polymer crystal element. Each pixel cell may be independently controlled by a respective plurality of electrodes, and the one or more pixel cells generate a determined pixel pattern when exposed to the EUV light for use in lithography.

In some embodiments, configuring the one or more pixel cells may include applying a first voltage to set the polymer crystal element in a first orientation such that the polymer crystal element absorbs the EUV light when in the first orientation.

In some embodiments, configuring the one or more pixel cells may include applying a second voltage to set the polymer crystal element in a second orientation such that the polymer crystal element reflects the EUV light when in the second orientation.

In some embodiments, the polymer crystal-based photomask may further include: a substrate on which the one or more pixel units are formed; and a thin film layer covering the one or more pixel units to prevent contamination.

In some embodiments, the polymer crystal-based photomask may further include an active layer between the substrate and the one or more pixel cells, and the active layer includes circuitry connected to the plurality of electrodes.

In some embodiments, the polymer crystal-based photomask may further include one or more slider rails and a motor configured to rotate the polymer crystal-based photomask.

In some embodiments, the polymer crystal-based photomask may further include multiple layers of pixel cells stacked on the substrate, each layer of pixel cells configured to interact with different wavelengths of the EUV light.

In some embodiments, the polymeric crystalline element may be a Cholesteric Liquid Crystal (CLC) material.

In some embodiments, the polymer crystal-based photomask may further include a back plate configured to cool the one or more pixel cells.

In some embodiments, the polymer crystal-based photomask may further include a temperature control component for monitoring and controlling the temperature of the photomask.

It should be understood that any feature described herein as being suitable for incorporation into one or more aspects or one or more embodiments of the present disclosure is intended to be generic to any and all aspects and any and all embodiments of the present disclosure. Other aspects of the present disclosure will be appreciated by those skilled in the art from the specification, claims and drawings of the present disclosure. The foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.

Drawings

FIG. 1 depicts a schematic diagram of a system for performing EUV lithography in accordance with one or more embodiments.

FIGS. 2A-2C illustrate example mask patterns associated with an OPC process in accordance with one or more embodiments.

FIG. 3 illustrates a cross-sectional view of a photomask in accordance with one or more embodiments.

Fig. 4A-4C illustrate cross-sectional views of a photomask under incident EUV light in accordance with one or more embodiments.

Fig. 5A-5B illustrate graphical representations of photomasks in accordance with one or more embodiments.

FIG. 6 is a flow diagram that illustrates a process of generating a photomask for EUV lithography, in accordance with one or more embodiments.

FIG. 7 is a block diagram illustrating components of an example machine capable of reading instructions from a machine-readable medium and executing the instructions in a processor in accordance with one or more embodiments.

Detailed Description

The figures (drawings) and the following description describe certain embodiments by way of illustration only. Those skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods may be employed without departing from the principles described. Wherever possible, like or similar reference numerals refer to like or identical structural elements or to like or similar functions. If multiple elements share a common number followed by a different letter, then the elements are similar or identical. The numbers themselves refer to any one or any combination of these elements.

Embodiments relate to an EUV photomask having a pixel array with a polymer crystal (such as a liquid crystal) that converts absorption of EUV light into reflection by changing the orientation of the polymer crystal. The pixel array includes a plurality of pixel units controlled by a plurality of electrodes. By using pixel cells that are capable of selectively absorbing or reflecting EUV light, the photomask may be modified in situ depending on OPC, the angle of EUV light used, the type of pattern to be transferred onto the wafer with photoresist, or some combination thereof. Since a polymer crystal based photomask may allow for correction and correction of OPC-related problems by adjusting electrodes (e.g., thin film transistors) that control crystal orientation, rather than undergoing very expensive mask redesign, the proposed design will enable rapid prototyping without the need for a semiconductor mask chamber. In addition, since the polymer crystal based photomask can be programmed to exhibit different layers, the need for multiple masks is reduced, enabling the time required for mask swap out to be reduced.

FIG. 1 depicts a schematic diagram of a system 100 for performing EUV lithography in accordance with one or more embodiments. The system 100 may include a light source 102, a mask 104, a wafer 106, and a plurality of optical components. The plurality of optical components may include one or more collection/illumination optics 108a and 108b (collectively, "illumination optics 108") and one or more projection optics 110a and 110b (collectively, "projection optics 110"). The light source 102 generates light and transmits the light through one or more illumination optics 108 onto the mask 104. The light is in the EUV wavelength range, about 13.5nm or in the range of 13.3nm to 13.7 nm. Mask 104 is a reflective EUV photomask. In some embodiments, the mask 104 may have dimensions of 6 inches by 6 inches and be made of a stack of multiple layers (e.g., up to 40 layers) of molybdenum and silicon (Mo/Si). Projection optics 110 transfers the pattern generated by mask 104 onto wafer 106, exposing the photoresist on wafer 106 according to the pattern. The exposed photoresist is then developed to produce a patterned photoresist on the wafer 106. This is used to fabricate structures on a wafer, for example, by deposition, doping, etching, or other processes. Other types of lithography systems may also be used, including the use of transmissive masks and/or optics at other wavelengths including Deep Ultraviolet (DUV), and the use of positive or negative photoresists. In some embodiments, the system 100 may also include a controller 120 to control the system 100 to perform a lithographic process. The controller 120 may include a processor and a computer readable storage medium. The controller 120 may receive instructions including a target photomask design and generate a pattern of pixels of the mask 104 for lithography. In some embodiments, the controller 120 is in communication with the mask 104 and may be used to dynamically adjust the mask pattern during a lithographic process (e.g., as described below with respect to fig. 6). Alternatively, the controller 120 may be a stand-alone computer capable of communicating with the system 100, which may provide control and/or configuration data to the EUV system 100.

Optical Proximity Correction (OPC) is a lithographic enhancement technique that is commonly used to compensate for image errors due to diffraction or process effects. Due to limitations in light to preserve edge placement integrity of the original design, irregularities (e.g., narrower or wider line widths than the design) may occur in the projected image (i.e., etched image on the wafer) after processing. If such distortion is not corrected, the electrical properties of the product being manufactured may be severely altered. OPC can correct these errors by changing the pattern on the photomask used for imaging, for example, by shifting the edges or adding additional polygons to the pattern written on the photomask. The objective is to reproduce as much as possible the original layout drawn by the designer on the wafer. During OPC, elements at the design level are represented as a set of polygons that are inscribed on a pixelated template, which is a mask. The design of the mask may be adjusted based on the angle of incidence, diffraction, interference, divergence, wavelength, etc. of the light to ensure that the desired pattern is printed on the wafer (and to address quality degradation to avoid distortion). For example, fig. 2A-2C below illustrate example mask patterns associated with an OPC process in accordance with one or more embodiments. Fig. 2A shows an example of a desired mask pattern, while fig. 2B shows an OPC-adjusted mask pattern that is adjusted in consideration of the manner in which light is reflected from a photomask (e.g., the change in the angle at which light interacts with the photomask). Fig. 2C shows a pattern generated by using the OPC-adjusted mask. Through an exposure process, a mask projects EUV light onto a photoresist coating on a silicon wafer, and then the exposed areas are etched to form target circuits on the silicon wafer. If the mask and/or OPC is not properly completed, distortions of the pattern are observed, which can lead to circuit failures (e.g., insufficient connection of corners to underlying vias, metal shorts, increased capacitance, and/or other problems).

For advanced lithography processes, a large number of EUV photomasks may be required, for example, about 50 EUV photomasks may be required for a 5nm technology node. In another example, multiple masks are required to create Fin Field-effect Transistor (FinFET) or Back End of Line (BEOL). About 10 to 15 layers of metal lines form the logic traces of the 14nm node. Different types of masks may be used, such as metallization masks, ohmic contact masks, emitter diffusion masks, base diffusion masks, isolation diffusion masks, buried masks, and the like. In some embodiments, several masks are required per layer to ensure that the desired pattern is etched correctly in the photoresist. In addition, defects in the photomask (e.g., due to amplitude (amplitude) defects, phase defects, and improper OPC completion) may require redesigning the photomask, which further increases costs. Embodiments of the present disclosure present a polymer crystal based photomask that allows a user to optimize OPC during a photolithography process. By controlling the electric field applied to the polymer crystal elements in the photomask, the polymer crystal elements can change their orientation to reflect or absorb incident EUV light. In this way, the desired pattern of the photomask may be achieved and adjusted during the lithographic process without creating a new mask.

FIG. 3 illustrates a cross-sectional view of a photomask 300 according to one or more embodiments. As shown in fig. 3, photomask 300 may include substrate 302, active layer 304, thin film layer 306, and one or more pixel cells 310. Substrate 302 may comprise silicon and provide structural support for photomask 300. An active layer 304 is formed between the substrate 302 and one or more pixel cells 310. The active layer 304 includes a circuit connected to each pixel unit 310.

Each pixel cell 310 may include at least one polymer crystal element 312 and a plurality of electrodes 314. In some embodiments, plurality of electrodes 314 are configured to divide photomask 300 into arrays and/or individual pixel cells 310. The polymer crystal element 312 may be a liquid crystal element configured to interact with EUV light based on the orientation of the polymer crystal element 312. In some embodiments, each pixel cell 310 may include a plurality of polymer crystal elements 312 formed as an array and/or stacked in a plurality of layers. For example, photomask 300 may include multiple layers of pixel cells 310 stacked on substrate 302, each layer of pixel cells 310 may be configured to interact with EUV light of different wavelengths. The plurality of electrodes 314 are connected to circuits in the active layer 304. In some embodiments, photomask 300 may further include one or more thin film transistors (Thin Film Transistor, TNT) coupled to electrode 314 to control the orientation of polymer crystal element 312. The electrode 314 is configured to be electrically connected to the polymer crystal element 312 to control the orientation of the polymer crystal element 312 by applying a voltage. Each pixel cell 310 may be independently controlled by a corresponding plurality of electrodes 314. Alternatively, adjacent pixel cells 310 may share at least a portion of the plurality of electrodes 314, and some of the plurality of pixel cells 310 may form a plurality of groups. The pixel cells 310 in each group may be commonly controlled by the same electrode 314.

In some embodiments, the polymer crystal element 312 may be a Cholesteric Liquid Crystal (CLC) material. CLC materials may be used for selective reflection, wherein the reflection change may be voltage induced (e.g., based on a voltage applied at a set angle relative to the helical axis of the polymer). In some embodiments, other possible stimuli (e.g., heat, mechanical compression/shear, or another wavelength of light (e.g., for CLC materials containing azobenzene chiral dyes)) may be used to control the selective reflectivity of the CLC material. In some embodiments, multiple layers of CLCs may be used to interact with multiple different wavelengths, as the orientation of the helical axis of the polymer crystal may affect how the polymer crystal element reflects light of different wavelengths.

Fig. 4A-4C illustrate cross-sectional views of a photomask under incident EUV light in accordance with one or more embodiments. The orientation of the polymer crystal element 312 may be changed by an electric field (e.g., caused by a small voltage), and thus the optical properties are affected accordingly. For example, the electrodes 314 in the pixel cell 310 may be configured to apply a voltage at a set angle relative to the helical axis of the polymer crystal element 312 (e.g., liquid crystal) to control the orientation of the polymer. In one example, the electrode 314 applies a first voltage to set the polymer crystal element 312 in a first orientation such that the polymer crystal element 312 absorbs incident EUV light, for example, a pixel cell 310a as shown in fig. 4A. In another example, the electrode 314 may apply a second voltage to set the polymer crystal element in a second orientation such that the polymer crystal element 312 reflects incident EUV light, for example, the pixel cell 310B shown in fig. 4B. The polymer crystal elements 312 in the pixel cells 310a and 310b are oriented based on the potential difference between the voltages of the plurality of electrodes 314, as shown in fig. 4C, and one or more of the pixel cells 310a and 310b generates a pattern for lithography when exposed to EUV light.

Thin film layer 306 may be a thin transparent film that covers photomask 300 during a lithography process. For example, the thin film layer 306 may be made of polysilicon. Thin film layer 306 is a dust cap because it prevents particles and contaminants from falling onto photomask 300. The thin film layer 306 is positioned on the pixel cell 310 and is exposed to incident EUV light. In some embodiments, pixel cell 310 may also include an orientation layer 316 configured to ensure proper mask orientation and to check orientation accuracy.

Fig. 5A-5B illustrate a graphical representation of a photomask 500 in accordance with one or more embodiments. The orientation of the polymer crystal elements 520 in different pixel cells 510 may be different. Defining the substrate surface as a basal plane, the polymer crystal element 520a in the pixel cell 510a being perpendicular to the basal plane; while the polymer crystal elements 520b in the other pixel cells 510b are parallel to the base plane (or at least have an acute angle). When the polymer crystal element 520a is perpendicular to the base plane (defined as the off position), the polymer crystal element 520a may absorb incident EUV light. On the other hand, when the polymer crystal element 520b is parallel to the basal plane (defined as the open position), the polymer crystal element 520b may reflect incident EUV light. In some embodiments, the polymer crystal elements 520 in each pixel cell 510 are controlled by the same electrode and are therefore oriented in the same direction. In this way, the photomask 500 is divided into the respective pixel units 510, so that the photomask 500 can be a display having a region that absorbs EUV light and a region that reflects EUV light. In this way, the user can correct OPC during the photolithography process and achieve very high and accurate photolithography.

In some embodiments, photomask 500 may include one or more backplanes as shown in FIG. 5A to cool polymer crystal elements 520a and 520b (collectively, "polymer crystal elements 520") in pixel cells 510a and 510b (collectively, "pixel cells 510"), respectively. The photomask 500 may be divided into individual pixel cells 510 by one or more electrodes 514. The physical properties of the polymer crystal element 520 may be affected by temperature because thermal energy may cause the polymer crystal element 520 to undergo certain crystallization transformations (e.g., to "reset" the orientation of the polymer crystal element 520 to the most favorable orientation related to entropy), which may interfere with electrode orientation control of the polymer crystal element 520. To mitigate thermal interference, in some embodiments, photomask 500 may include components for active temperature monitoring and control to improve performance and lifetime. As shown in fig. 5A, a backplate 530 at the bottom of the photomask 500 is configured to perform active temperature management to maintain the performance of the polymer crystal elements in the photomask 500.

In some embodiments, photomask 500 may further include slider rails along the X-axis and the Y-axis. As shown in fig. 5B, the X-axis and the Y-axis are parallel to the base plane and perpendicular to each other. In some embodiments, a piezoelectric-based motor is connected to the slider track. In some embodiments, pixel cells 510 of photomask 500 may generate a pixelated stamp on a wafer (e.g., due to non-reflective areas corresponding to electrodes between pixels in a pixel array). Using slider tracks and piezoelectric-based motors, photomask 500 may be rotated in the X-Y plane (e.g., translated along the +X direction, -X direction, +Y direction, and/or-Y direction) to reduce or mitigate pixelated imprinting.

FIG. 6 is a flow diagram that illustrates a process of generating a photomask for EUV lithography, in accordance with one or more embodiments. An EUV lithography system (e.g., system 100) may include a controller 120 (e.g., controller 120) for generating a photomask. The controller may include a processor and a computer readable storage medium. As shown in fig. 6, a controller receives 610 instructions including a target photomask design (e.g., as shown in fig. 2A) to perform EUV lithography. To correct for image errors that may occur during the lithographic process, the controller generates 620 an OPC-adjusted mask pattern (e.g., as shown in fig. 2B) based on the target photomask design. The EUV lithography system includes a photomask based on a polymer crystal, and the controller determines 630 a pixel pattern based on the OPC-adjusted mask pattern. A photomask based on polymer crystals may include one or more pixel cells containing polymer crystal elements. The polymer crystal elements may interact with EUV light depending on their orientation. The orientation of the polymer crystal element may be controlled by a plurality of electrodes. The electrodes may set the polymer crystal element in a first orientation by applying a first voltage, and the polymer crystal element absorbs EUV light; alternatively, the electrodes may set the polymer crystal element in the second orientation by applying a second voltage, and the polymer crystal element reflects EUV light. Thus, by controlling the electrodes, the EUV lithography system configures 640 pixel cells of the polymer crystal based photomask based on the determined pixel pattern, such that the polymer crystal based photomask may generate a desired pattern for lithography when exposed to EUV light.

The photomasks disclosed herein use pixels of polymeric material (e.g., liquid crystals) to achieve rapid prototyping of test wafers and to reduce manufacturing time, thereby significantly reducing mask development and mask room investment. For example, in some embodiments, a photomask based on a single polymeric material may be programmed to display different patterns, thereby reducing costs associated with replacement or redesign of a traditional photomask. The disclosed photomasks may also allow for rapid optimization of layer thickness based on performance, where layer thickness in finfets and advanced technology nodes may be optimized without requiring expensive mask redesign. In some embodiments, microlenses and waveguides can be prototyped, tested, and manufactured in significantly less time and less monetary investment.

FIG. 7 is a block diagram illustrating components of an example machine capable of reading instructions from a machine-readable medium and executing the instructions in a processor (e.g., controller 120). In particular, FIG. 7 shows a diagrammatic representation of machine in the example form of a computer system 700 within which program code (e.g., software) for causing the machine to perform any one or more of the methodologies discussed herein may be executed. The program code may include instructions 724 executable by the one or more processors 702. In alternative embodiments, the machine operates as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine may operate in the capacity of a server machine or a client machine in the server-client network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.

The machine may be a server computer, a client computer, a Personal computer (Personal Computer, a PC), a tablet PC, a Set-top Box (STB), a Personal digital assistant (Personal DIGITAL ASSISTANT, PDA), a cellular telephone, a smart phone, a tablet computer, a network device, a network router, switch or bridge, or any machine capable of executing instructions 724 that specify actions to be taken by that machine (sequentially or otherwise). Furthermore, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute instructions 124 to perform any one or more of the methodologies discussed herein.

The example computer system 700 includes a Processor 702 (e.g., a central processing unit (Central Processing Unit, CPU), a graphics processing unit (Graphics Processing Unit, GPU), a digital signal Processor (DIGITAL SIGNAL Processor, DSP), one or more Application SPECIFIC INTEGRATED Circuits (ASIC), one or more Radio-frequency integrated circuits (RFIC), or any combination thereof), a main memory 704, and a static memory 706, which are configured to communicate with each other via a bus 708. The computer system 700 may also include a visual display interface 710. The visual interface may include a software driver that is capable of displaying a user interface on a screen (or display). The visual interface may display the user interface directly (e.g., on a screen) or indirectly on a surface or window or the like (e.g., via a visual projection unit). For ease of discussion, the visual interface may be described as a screen. Visual interface 710 may include or may interact with a touch screen. The computer system 700 may also include an alphanumeric input device 712 (e.g., a keyboard or touch screen keyboard), a cursor control device 714 (e.g., a mouse, trackball, joystick, motion sensor, or other pointing device), a storage unit 716, a signal generation device 718 (e.g., a speaker), and a network interface device 720, which are also configured to communicate via the bus 708.

The storage unit 716 includes a machine-readable medium 722 having stored thereon instructions 724 (e.g., software) embodying any one or more of the methodologies or any one or more of the methodologies described herein. The instructions 724 (e.g., software) may also reside, completely or at least partially, within the main memory 704 or within the processor 702 (e.g., within a processor's cache memory) during execution thereof by the computer system 700, the main memory 704 and the processor 702 also constituting machine-readable media. Instructions 724 (e.g., software) may be transmitted or received over a network 726 via the network interface device 720.

While the machine-readable medium 722 is shown in an example embodiment to be a single medium, the term "machine-readable medium" should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, or associated caches and servers) that are capable of storing the instructions (e.g., instructions 724). The term "machine-readable medium" shall also be taken to include any medium that is capable of storing instructions (e.g., instructions 724) for execution by the machine and that cause the machine to perform any one or more of the methodologies disclosed herein. The term "machine-readable medium" includes, but is not limited to, data repositories in the form of solid-state memory, optical media, and magnetic media.

Additional configuration information

The foregoing description of the embodiments has been presented for purposes of illustration; it is not intended to be exhaustive or to limit the patent rights to the precise form disclosed. Those skilled in the relevant art will appreciate that many modifications and variations are possible in light of the above disclosure.

Some portions of this specification describe embodiments in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to effectively convey the substance of their work to others skilled in the art. When described functionally, computationally, or logically, the operations are understood to be implemented by computer programs or equivalent circuits or microcode or the like. Furthermore, it has proven convenient at times, to refer to these arrangements of operations as modules, without loss of generality. The described operations and their associated modules may be implemented in software, firmware, hardware, or any combination thereof.

Any of these steps, operations, or processes described herein may be performed or implemented by one or more hardware or software modules alone or in combination with other devices. In one embodiment, the software modules are implemented using a computer program product comprising a computer readable medium containing computer program code executable by a computer processor to perform any or all of the steps, operations, or processes described.

Embodiments may also relate to an apparatus for performing the operations herein. The apparatus may be specially constructed for the required purposes, and/or the apparatus may comprise a general-purpose computing device selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory, tangible computer readable storage medium that may be coupled to a computer system bus or in any type of medium suitable for storing electronic instructions. Furthermore, any computing system referred to in this specification may comprise a single processor or may be an architecture employing multiple processor designs to improve computing capability.

Embodiments may also relate to a product resulting from the computing process described herein. Such an article of manufacture may comprise information generated by a computing process, stored on a non-transitory tangible computer-readable storage medium, and may comprise any embodiment of a computer program product or other data combination described herein.

Finally, the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the patent rights. Accordingly, it is intended that the scope of the patent claims not be limited by this detailed description, but rather by any claims based on the disclosure of the application herein. Accordingly, the disclosure of the embodiments is intended to be illustrative, but not limiting, of the scope of the patent claims, which is set forth below.

Claims (15)

1. A photomask, comprising:

A substrate; and

One or more pixel units formed on the substrate, each pixel unit comprising:

At least one polymer crystal element configured to interact with Extreme Ultraviolet (EUV) light based on an orientation of the polymer crystal element; and

A plurality of electrodes configured to control the orientation of the polymer crystal element by applying a voltage across the polymer crystal element;

Wherein each pixel cell is independently controlled by a respective said plurality of electrodes, and said one or more pixel cells generate a pattern for lithography when exposed to said EUV light.

2. The photomask of claim 1, wherein the plurality of electrodes set the polymer crystal element in a first orientation by applying a first voltage, and the polymer crystal element is configured to absorb the EUV light when in the first orientation.

3. The photomask of claim 1 or 2, wherein the plurality of electrodes set the polymer crystal element in a second orientation by applying a second voltage, and the polymer crystal element is configured to reflect the EUV light when in the second orientation.

4. A photomask according to claim 1,2 or 3, further comprising a thin film layer covering the one or more pixel cells to prevent contamination.

5. A photomask according to any of the preceding claims, further comprising an active layer located between the substrate and the one or more pixel cells, wherein the active layer comprises circuitry connected to the plurality of electrodes.

6. A photomask according to any of the preceding claims, wherein the polymer crystal element is a Cholesteric Liquid Crystal (CLC) material.

7. The photomask of any preceding claim, further comprising a back plate configured to cool the one or more pixel cells.

8. The photomask of any preceding claim, further comprising one or more slider rails and a motor configured to rotate the photomask.

9. The photomask of any preceding claim, further comprising a plurality of layers of pixel cells stacked on the substrate, each layer of pixel cells configured to interact with different wavelengths of the EUV light.

10. The photomask of any of the preceding claims, further comprising a temperature control component for monitoring and controlling the temperature of the photomask.

11. A method, comprising:

receiving an instruction comprising a target photomask design;

generating a mask pattern adjusted by Optical Proximity Correction (OPC) based on the photomask design;

determining a pixel pattern based on the mask pattern after OPC adjustment; and

Configuring one or more pixel cells of a polymer crystal based photomask based on the determined pixel pattern, wherein each of the one or more pixel cells comprises:

At least one polymer crystal element configured to interact with Extreme Ultraviolet (EUV) light based on an orientation of the polymer crystal element; and

A plurality of electrodes configured to control the orientation of the polymer crystal element by applying a voltage across the polymer crystal element.

12. The method of claim 11, wherein configuring the one or more pixel cells comprises one or more of:

i. Applying a first voltage to set the polymer crystal element in a first orientation such that the polymer crystal element absorbs the EUV light when in the first orientation;

Applying a second voltage to set the polymer crystal element in a second orientation such that the polymer crystal element reflects the EUV light when in the second orientation.

13. The method of claim 11 or 12, wherein the polymer crystal-based photomask further comprises:

A substrate on which the one or more pixel units are formed; and

A thin film layer covering the one or more pixel units to prevent contamination; and preferably

Wherein the polymer crystal-based photomask further comprises one or more of the following:

i. An active layer between the substrate and the one or more pixel cells, and including a circuit connected to the plurality of electrodes;

one or more slider rails and a motor configured to rotate the polymer crystal-based photomask;

A multi-layer pixel cell stacked on the substrate, each layer of pixel cells configured to interact with different wavelengths of the EUV light.

14. The method of claim 11, 12 or 13, wherein the polymeric crystalline element is a Cholesteric Liquid Crystal (CLC) material.

15. The method of any of claims 11 to 14, wherein the polymer crystal-based photomask further comprises one or more of:

i. a back plate configured to cool the one or more pixel cells;

and a temperature control component for monitoring and controlling the temperature of the photomask.