Lithography system and related methods for forming structures of different depths and shapes - Patents.com

Abstract

A method is provided that includes directing a plurality of radiation beams to a first area of ​​a first layer on a substrate, each beam incident on a different one of a plurality of portions in the first area, each portion having an area of ​​a first size, the plurality of radiation beams being directed to the first area based on a first pattern, the first pattern including a plurality of unit cells including a plurality of on cells and a plurality of off cells, each unit cell having an area smaller than the first size, the plurality of on cells identifying locations within the first area where a center of one of the plurality of radiation beams is focused, and the plurality of off cells identifying locations within the first area where none of the plurality of radiation beams is focused.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to lithography systems and methods. More particularly, embodiments described herein relate to lithography systems and methods for forming structures with varying dimensions (e.g., various depths) with fewer exposures, e.g., in a single pass. [Background technology]

[0002] Photolithography is widely used in the manufacture of semiconductor devices, such as for back-end processing of semiconductor devices, and in the manufacture of display devices, such as liquid crystal displays (LCDs). For example, large area substrates are often utilized in the manufacture of LCDs. LCDs or flat panel displays are commonly used for active matrix displays in computers, touch panel devices, personal digital assistants (PDAs), mobile phones, television monitors, and the like. Generally, flat panel displays include a layer of liquid crystal material as a phase change material at each pixel sandwiched between two plates. When power from a power source is applied across or through the liquid crystal material, the amount of light passing through the liquid crystal material at the pixel location can be controlled, i.e., selectively adjusted, to generate an image on the display.

[0003] To form structures having different depths using conventional lithography systems requires multiple passes of the substrate under the writeable area of ​​the lithography system, which reduces throughput.

[0004] Therefore, there is a need in the art for a lithography system and associated methods for forming structures having different depths that do not suffer from the throughput problems discussed above. Summary of the Invention

[0005] In one embodiment, a method is provided that includes directing a plurality of radiation beams to a first area of ​​a first layer on a substrate, each beam incident on a different one of a plurality of portions in the first area, each portion having an area of ​​a first size, the plurality of radiation beams being directed to the first area based on a first pattern, the first pattern including a plurality of on cells and a plurality of off cells, each unit cell having an area smaller than the first size, the plurality of on cells identifying locations in the first area where a center of one of the plurality of radiation beams is focused, and the plurality of off cells identifying locations in the first area where none of the plurality of radiation beams is focused.

[0006] In another embodiment, a method is provided. The method includes directing a first plurality of radiation beams to a first area of ​​a first layer on a substrate, each beam being incident on a different one of a plurality of portions in the first area. The method further includes directing a second plurality of radiation beams to a second area of ​​the first layer on the substrate, each beam being incident on a different one of a plurality of portions in the second area, each portion of the first area and the second area having an area of ​​a first size, the first plurality of radiation beams being directed to the first area based on a first pattern and the second plurality of radiation beams being directed to the second area based on a second pattern, the first pattern and the second pattern each including a plurality of unit cells each including a plurality of on cells and a plurality of off cells, and each unit cell of the first pattern and the second pattern includes a plurality of unit cells. The cell has an area smaller than the first size, the plurality of on cells of the first pattern identifying locations within the first area where a center of one of the first plurality of radiation beams is focused and the plurality of off cells of the first pattern identifying locations within the first area where none of the radiation beams of the first plurality of radiation beams is focused at their centers, the plurality of on cells of the second pattern identifying locations within the second area where a center of one of the second plurality of radiation beams is focused and the plurality of off cells of the second pattern identifying locations within the second area where none of the radiation beams of the second plurality of radiation beams is focused at their centers.

[0007] In another embodiment, a method is provided. The method includes directing a first plurality of radiation beams to a first region of a first area of ​​a first layer on a substrate, each beam of the first plurality of beams being incident on a different one of the plurality of portions in the first region. The method further includes directing a second plurality of radiation beams to a second region of the first area, each beam of the second plurality of beams being incident on a different one of the plurality of portions in the second region, each portion of the first region and the second region having an area of ​​a first size, the second plurality of radiation beams being directed to the first region of the first area based on a first pattern, and the second plurality of radiation beams being directed to the second region of the first area based on a second pattern, the first pattern and the second pattern each including a plurality of unit cells including a plurality of on cells and a plurality of off cells, and the first pattern and the second pattern each including a plurality of unit cells including a plurality of on cells and a plurality of off cells. Each unit cell of the turn has an area smaller than a first size, the plurality of on cells of the first pattern identifying locations within a first region where a center of one of the first plurality of radiation beams is focused and the plurality of off cells of the first pattern identifying locations within the first region where none of the radiation beams of the first plurality of radiation beams is focused at their centers, the plurality of on cells of the second pattern identifying locations within a second region where a center of one of the plurality of radiation beams is focused and the plurality of off cells of the second pattern identifying locations within the second region where none of the radiation beams of the second plurality of radiation beams is focused at their centers.

[0008] So that the above-listed features of the present disclosure may be understood in detail, a more particular description of the present disclosure briefly outlined above may be had by reference to embodiments, some of which are illustrated in the accompanying drawings, which should be noted, however, that the accompanying drawings represent only exemplary embodiments and therefore should not be considered as limiting the scope of the present disclosure, which may embrace other embodiments that are equally effective. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a lithography system, in accordance with one embodiment. [Diagram 2] 2 is a schematic diagram of an exemplary image projection system that may be used in the lithography system of FIG. 1, according to one embodiment. [Figure 3A] FIG. 2 is a top view of a substrate, according to one embodiment. [Figure 3B] FIG. 2 is a top view of a first radiation pattern according to one embodiment. [Figure 3C] FIG. 2 is a top view of a second radiation pattern according to one embodiment. [Figure 4] 10 is a process flow for a method 1000 of modifying different areas of a photoresist layer on a substrate with different radiation patterns, according to one embodiment. [Figure 5A] FIG. 2 is a top view of a substrate according to another embodiment. [Figure 5B] FIG. 2 is a top view of a first radiation pattern according to one embodiment. [Figure 5C] FIG. 2 is a top view of a second radiation pattern according to one embodiment. [Figure 5D] 4A-4C are top views of a third radiation pattern and a fourth radiation pattern according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] For ease of understanding, wherever possible, identical reference numerals have been used to designate identical elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without additional description.

[0011] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to lithography systems and methods. More particularly, embodiments described herein relate to lithography systems and methods for forming structures with varying dimensions (e.g., various depths) with fewer exposures, e.g., in a single pass.

[0012] 1 is a perspective view of a lithography system 100, according to one embodiment. The lithography system 100 may be a digital lithography system. The lithography system 100 includes a processing device 104, a stage 114, a slab 102, and a pair of tracks 116.

[0013] The stage 114 is supported by a pair of tracks 116 disposed on the slab 102. The stage 114 can be moved along the tracks 116 to different positions beneath the processing equipment 104. A substrate 120 is disposed on the stage 114. A photoresist layer can be disposed on the substrate 120. The processing equipment 104 includes equipment for directing radiation (e.g., ultraviolet radiation) toward the photoresist on the substrate 120 when the substrate 120 is disposed beneath a portion of the processing equipment 104. Although the following disclosure describes forming structures by physically altering portions of the photoresist layer (e.g., changing the solubility of the photoresist portions in a photoresist developer), the benefits of the present disclosure can apply to any layer that can be physically altered by any form of radiation.

[0014] The stage 114 is configured to move in an X-direction along a pair of tracks 116, which is indicated by the coordinate system shown in Figure 1. In one embodiment, which can be combined with other embodiments described herein, the pair of tracks 116 is a pair of parallel magnetic channels. As shown, each track in the pair of tracks 116 extends along a linear path.

[0015] The processing device 104 includes a support 108 and a processing unit 106. The support 108 is disposed on the slab 102. The support 108 of the processing device 104 forms an opening 112 across a pair of tracks 116. The processing unit 106 is supported by the support 108 above the slab 102. The pair of tracks 116 may extend through the opening 112. The opening 112 allows a stage 114 to move along the tracks 116 beneath the processing unit 106.

[0016] In one embodiment, which can be combined with other embodiments described herein, the processing unit 106 is a pattern generator configured to expose photoresist on the substrate 120 to radiation (e.g., UV radiation) in a photolithography process.

[0017] The processing unit 106 includes a plurality of image projection systems 200, each disposed within a case 110. Details of the image projection systems 200 are discussed below with reference to FIG. 2. FIG. 1 shows 18 cases 110 housing the image projection systems 200, each disposed within one of the cases 110. Only one image projection system 200 is shown to avoid cluttering the drawing. In other embodiments that can be combined with other embodiments described herein, the processing unit 106 can include fewer image projection systems (e.g., five image projection systems 200) or more image projection systems (e.g., 50 image projection systems). The processing unit 106 is used to directly write a pattern into a photoresist or other electromagnetic radiation sensitive material without a mask.

[0018] Lithography system 100 further includes a controller 122 and an encoder 118. Controller 122 is generally designed to facilitate automation of the processing methods described herein. Controller 122 can be any type of controller used in an industrial environment, such as a programmable logic controller (PLC). Controller 122 includes a processor 127, memory 126, and input / output (I / O) circuitry 128. Controller 122 can further include one or more of the components (not shown), such as one or more power supplies, clocks, communication components (e.g., network interface cards), and user interfaces, typically found in a controller of semiconductor equipment.

[0019] The memory 126 may include non-transitory memory. This non-transitory memory may be used to store programs and settings, as described below. The memory 126 may include one or more types of readily available memory, such as read-only memory (ROM) (e.g., Electrically Erasable Programmable Read-Only Memory (EEPROM), flash memory, floppy disk, hard disk, or random access memory (RAM) (e.g., non-volatile random access memory (NVRAM)).

[0020] The processor 127 is configured to execute various programs stored in the memory 126, such as a program configured to execute the method 1000 described below with reference to FIG. 4. During the execution of these programs, the controller 122 can communicate with I / O devices (e.g., the processing unit 104, the stage 114, and the encoder 118) via the I / O circuitry 128. For example, during the execution of these programs and during communication via the I / O circuitry 128, the controller 122 can control outputs, for example, to control the position of the stage 114 using information from feedback devices (e.g., the encoder 118) and information from other inputs (e.g., sensors) in the lithography system 100. The memory 126 can further include various operational settings used to control the lithography system 100. For example, the settings can include pattern information for different radiation patterns to apply to one or more substrates. In some embodiments, the processing unit 104 can include a controller that can store information regarding patterns to apply to substrates for different processes.

[0021] The processing equipment 104 may further provide information regarding the status of the substrate processing to the controller 122. For example, the processing equipment 104 may provide information to the controller 122 to inform the controller 122 that a portion of the substrate processing is complete. The controller 122 may further provide information to the processing equipment 104, such as the position of the stage 114.

[0022] The encoder 118 may be coupled to the stage 114. The encoder 118 may be used to provide position information of the stage 114 to a controller 122. The controller 122 may use this position information to control the image projection system 200 in the processing unit 106 such that designated portions of the photoresist on the substrate 120 may be exposed with a predetermined amount of radiation from the image projection system 200, thereby forming structures on the substrate 120 having an intended depth and shape.

[0023] Programs (e.g., software instructions) stored in memory 126 and readable by controller 122, sometimes referred to as imaging programs, determine which tasks can be performed on a given substrate 120. These programs can include data regarding the radiation pattern to apply, as well as code for monitoring and controlling processing time and substrate position during the process. The data regarding the radiation pattern (e.g., first pattern 310 described below with reference to FIG. 3B) can correspond to a pattern to be written into the photoresist using electromagnetic radiation provided from image projection system 200. As a result of how traditional lithography processes have used physical masks to perform lithography, this pattern data can also be referred to as mask pattern data, even though no physical mask is used to perform the digital lithography processes described herein.

[0024] Controller 122 may further include a rasterizer that assists in converting a radiation pattern (e.g., a first pattern 310 described below with reference to FIG. 3B ) stored in a virtual mask file (e.g., an image file) in memory 126 into data that can be used by image projection system 200 to form the pattern on a photoresist layer on substrate 120. The rasterizer may include a rasterizer computation engine, which may include one or more field programmable gate arrays (FPGAs), graphics processing units (GPUs), or a combination of FPGAs and GPUs.

[0025] Although the controller 122 is shown as a single component, this is not required. In some embodiments, the controller 122 may be distributed across multiple components of the lithography system 100. For example, the virtual mask file may be stored on a server, while a separate controller may be used to control the movement of the stage 114 and a separate controller may be used to direct radiation from the image projection system 200 to a photoresist layer on the substrate 120. Any servers and separate controllers used may each include a non-transitory memory and a processor for executing programs stored in the non-transitory memory to perform the methods described below.

[0026] Substrate 120 may be formed of any suitable material, including, but not limited to, silicon (Si), silicon dioxide (SiO2), fused silica, quartz, glass, silicon carbide (SiC), germanium (Ge), silicon germanium (SiGe), indium phosphide (InP), gallium arsenide (GaAs), gallium nitride (GaN), or sapphire. In some embodiments, which may be combined with other embodiments described herein, substrate 120 is formed of other materials that may be used as part of a flat panel display.

[0027] A film layer (e.g., a film layer including chromium) may be formed on the substrate 120. A photoresist layer may be formed on the film layer. In some embodiments, the photoresist layer may be sensitive to electromagnetic radiation, such as UV or deep UV "light." After exposing the photoresist to the electromagnetic radiation, the photoresist is developed to leave a specified pattern.

[0028] 2 is a schematic diagram of an exemplary image projection system 200 that may be used in lithography system 100. As described above with reference to FIG. 1, processing unit 106 includes multiple image projection systems 200, each disposed within a single case 110. Each image projection system 200 can provide radiation to a different portion of the photoresist on substrate 120. One of these image projection systems 200 will now be described with reference to FIG. 2.

[0029] The image projection system 200 includes a light source 202, an aperture 204, a lens 206, a frustrated prism assembly 208, a spatial light modulator 210, and projection optics 212. The light source 202 can emit a light beam 201 through the aperture 204 to the lens 206. The lens 206 can direct the light beam 201 to the frustrated prism assembly 208, which can reflect the light to multiple mirrors on the spatial light modulator 210. Each of the multiple mirrors on the spatial light modulator 210 can be individually controlled (e.g., electrically controlled) to be on or off. The "on" mirrors of the spatial light modulator 210 can then reflect multiple writing beams 203 through the projection optics 212 to different portions of the photoresist on the substrate 120.

[0030] In some embodiments, for example when the light source 202 is a laser, each beam 203 of the multiple beams can include multiple shots. In some of these embodiments, the multiple shots are separate pulses from the laser. In some of these embodiments, the multiple shots can be a specified number of shots per individual location to which the beam 203 is directed. For example, in some embodiments, the multiple shots can be between about 50 shots and about 500 shots per individual location (see, e.g., portion 305 described below with reference to FIG. 3B). In other embodiments, the multiple shots can be varied for different locations on the photoresist to allow for different methods of controlling the amount of radiation applied to each individual location on the photoresist.

[0031] The multiple write beams 203 can physically alter a photoresist layer (first layer) on the substrate 120. For example, radiation from the multiple write beams 203 can change the solubility of the photoresist to one or more photoresist developers. An off mirror of the spatial light modulator 210 can result in (1) a corresponding portion of the photoresist not being exposed to radiation, or (2) a corresponding portion of the photoresist being exposed to less radiation. As will be described in more detail below, radiation patterns can be directed at the photoresist on the substrate 120 to form structures having different depths and / or shapes. When all other operating parameters for the radiation (e.g., radiation duration, power level, duty cycle, shot multiplicity, etc.) are held constant, radiation patterns with a higher ratio of "on" mirrors to total mirrors can generally physically alter the photoresist to a greater depth than radiation patterns with a lower ratio of "on" mirrors to total mirrors.

[0032] The light source 202 may be any suitable light source capable of generating one or more wavelengths, such as a light emitting diode (LED) or a laser. In one embodiment, which may be combined with other embodiments described herein, in which the light source 202 is a laser, the wavelength emitted by the laser may be in the blue or near ultraviolet (UV) range, such as a wavelength shorter than about 450 nm.

[0033] Projection optics 212 may include a projection lens, for example a 10× objective lens, used to project radiation onto substrate 120 .

[0034] In one embodiment, the spatial light modulator 210 is a digital micromirror device (DMD). Each mirror of the multiple mirrors in the DMD may correspond to a unit cell of a pattern described below (see, for example, unit cell 320 described below with reference to FIG. 3B). In some embodiments, which may be combined with other embodiments described herein, the DMD includes more than about 4,000,000 mirrors. Although the individually controllable elements used to direct the radiation pattern are generally described in this disclosure as mirrors (e.g., digital micromirrors), these individually controllable elements may also include liquid crystal displays (LCDs), liquid crystal over silicon (LCoS) devices, ferroelectric liquid crystal on silicon (FLCoS) devices, and microshutters.

[0035] 3A is a top view of the substrate 120, according to one embodiment. In FIG. 3A, the substrate 120 includes a photoresist layer 121, a first modified portion 300, and a second modified portion 350. The modified portions 300, 350 are modified portions of the photoresist layer 121 (also referred to as the first layer) on the substrate 120. The first modified portion 300 was formed by directing a first radiation pattern 310 (see FIG. 3B) to a first area 301 of the photoresist layer 121. The second modified portion 350 was formed by directing a second radiation pattern 360 (see FIG. 3C) to a second area 351 of the photoresist layer 121.

[0036] The modified portions 300, 350 are physically altered relative to unaltered portions of the photoresist layer 121. The modified portions 300, 350 are physically altered by radiation directed at corresponding first areas 301 and second areas 351. For example, the radiation may alter the solubility of the photoresist layer 121 in the areas 301, 351 to enable application of a photoresist developer to the substrate 120, thereby enabling structures (e.g., vias) to be formed from the modified portions 300, 350.

[0037] 3B illustrates a top view of a first radiation pattern 310 according to one embodiment. Radiation can be directed to a first area 301 according to the first radiation pattern 310 to form the first modified portion 300 of FIG. 3A. Because portions of the first pattern 310 can correspond to portions of the first area 301, in the following disclosure some portions of the first pattern 310 are also referred to as portions of the first area 301. The hatched areas of the first pattern 310 identify corresponding portions of the first area 301 of the photoresist 121 near which the center of a radiation beam (e.g., beam 203 in FIG. 2) is focused, while the unhatched areas of the first pattern 310 identify corresponding portions of the first area 301 near which no radiation beam is focused. This concept of the center of the radiation beam focusing on a particular area is explained in more detail below.

[0038] The first pattern 310 includes a number of unit cells 320 for identifying whether radiation is directed to a particular location in a given area, such as the first area 301, and the center of that radiation is focused at that particular location. The unit cells 320 include on cells 320A and off cells 320B. The shaded areas of the first pattern 310 include on cells 320A (some of which are shown) that identify portions of the first area 301 where a radiation beam is directed in accordance with the first pattern 310 and the center of that radiation beam is focused. Conversely, the unshaded areas of the first pattern 310 include off cells 320B (some of which are shown) that identify portions of the first area 301 where no radiation beam in accordance with the first pattern 310 is focused at its center.

[0039] The first pattern 310 is a ring-shaped pattern including a group of on-cells 320A and off-cells 320B arranged in concentric rings. The first pattern 310 includes a central portion 315 of the on-cells 320A. The central portion 315 is surrounded by several ring-shaped portions. A first ring-shaped portion 311 of the off-cells 320B is arranged around the central portion 315. A second ring-shaped portion 312 of the on-cells 320A is arranged around the first ring-shaped portion 311. A third ring-shaped portion 313 of the off-cells 320B is arranged around the second ring-shaped portion 312. A fourth ring-shaped portion 314 of the on-cells 320A is arranged around the third ring-shaped portion 313.

[0040] The first ring-shaped portion 311 is disposed between the central portion 315 and the second ring-shaped portion 312 and is in contact with the central portion 315 and the second ring-shaped portion 312. The second ring-shaped portion 312 is disposed between the first ring-shaped portion 311 and the third ring-shaped portion 313 and is in contact with the first ring-shaped portion 311 and the third ring-shaped portion 313. The third ring-shaped portion 313 is disposed between the second ring-shaped portion 312 and the fourth ring-shaped portion 314 and is in contact with the second ring-shaped portion 312 and the fourth ring-shaped portion 314. The fourth portion 314 is the outermost portion of the first pattern 310.

[0041] The first pattern 310 is used to direct radiation to the first area 301 of FIG. 3A. The lithography system 100 (see FIG. 1) can be used to direct the radiation to the first area 301 (see FIG. 3A) according to the first pattern 310 (see FIG. 3B). For example, one or more of the image projection systems 200 (see FIG. 2) of the lithography system 100 can be used to direct the radiation to the first area 301. In one embodiment, the image projection system 200 can include an array of a sufficient number of mirrors that can be electrically controlled to on and off states corresponding to all unit cells 320 of the multiple unit cells 320 of the first pattern 310, such that radiation is directed to the first area 301 from these separate mirrors that take on a geometric pattern corresponding to the first pattern 310.

[0042] In another embodiment, the image projection system 200 can electrically control the mirrors to form the first pattern 310 over time. For example, in some embodiments, a single mirror of one of the image projection systems 200 can be used to direct a corresponding radiation beam to two or more of the multiple On-cells 320A of the first pattern 310. Directing a corresponding radiation beam to two or more On-cells 320A of the first pattern using a single mirror can be achieved, among other things, by (1) moving the substrate 120 using the stage 114 and actuating the mirror before and after the stage movement, (2) changing the angle of the mirror such that the radiation beam reflected from the mirror is directed to a different position on the substrate, and / or (3) changing the trajectory of the beam reflected from the mirror with other optical components in the lithography system 100.

[0043] The radiation beam applied to the first area 301 according to the first pattern 310 is larger than the components of the first pattern 310 (i.e. larger than the unit cells 320 forming the hatched and unhatched areas of the first pattern 310). For example, applying a radiation beam to the first area 301 according to the first unit cell 320A1 results in a single radiation beam being incident on a portion 3051 of the first area 301. The portion 3051 extends from the hatched portion of the first pattern 310 and the fourth portion 314 of the first area 301 into the unhatched portion of the third portion 313. Thus, radiation may also be directed to portions of the first area 301 that correspond to the unhatched areas of the first pattern 310. This is because the unshaded portions of the first pattern 310 merely indicate that there is no radiation beam centered on a portion of the first area 301 that corresponds to the unshaded area of ​​the first pattern 310. For example, because off-cell 320B2 is in the unshaded portion of the first pattern 310, no radiation beam is directed into the first area 301 to be centered on off-cell 320B2 in portion 3052 of the first area 301.

[0044] To avoid cluttering the drawing, only a few unit cells 320 are shown in FIG. 3B, but if all unit cells 320 were shown, the unit cells 320 would fill the entire first pattern 310, e.g., in a non-overlapping arrangement. In one embodiment, the unit cells 320 can be arranged in a two-dimensional array (e.g., a grid) as shown in FIG. 3B. In some embodiments, but not required, each unit cell 320 of the unit cells 320 can have the same size (e.g., all unit cells 320 are square with the same size). The area of ​​each unit cell 320 can be smaller than the area of ​​the portion 305. For example, in FIG. 3B, the area of ​​the unit cells 320 is 1 / 9 of the area of ​​the portion 305 because nine unit cells 320 can fit inside and fill each portion 305. In other embodiments, the unit cells 320 can have an area that is smaller than the area of ​​the portion 305 by more than 1 / 9 or by less than 1 / 9.

[0045] When an area, such as the first area 301, is selected to receive the first radiation pattern 310, the unit cells 320 of the first pattern 310 correspond to the location of the first area 301. For example, when the first area 301 is selected to receive radiation according to the first pattern 310, the unit cell 320A3 in the top left corner of the first pattern 310 may correspond to the radiation that the top left portion 3053 receives when radiation is applied according to the location of the unit cell 320A3 of the first pattern 310. Note that the radiation applied to the first area 301 is larger than the first pattern 310 because the applied radiation beam is larger than the unit cell 320. For example, as shown by the top left corner portion 3053, the first area 301 is larger than the first pattern 310 by one unit cell 320 on all four sides of the first pattern 310.

[0046] Because the radiation beams are incident on portions 305 of the first area 301 that are larger than the unit cells 320, the portions 305 of the first area 301 on which the radiation beams are incident overlap each other. The amount of overlap depends on the area of ​​the unit cells 320 compared to the area of ​​the portions 305. As shown in portion 3051, nine unit cells 320 can fit inside one portion 305, completely filling one portion 305. When radiation from different on cells 320A overlap each other in a single area, the more unit cells 320 in the portion 305, the greater the number of beams that can be incident on a given location of the first area 301. For example, if the portion 305 is completely filled with the nine shaded unit cells 320A, then the central location of the portion 305 (i.e., a location the size of a unit cell 320) will receive nine different radiation beams that overlap each other when radiation is applied according to this pattern.

[0047] Thus, where each location of the first area 301 receives at least one radiation beam, the locations of the area 301 may range from receiving one radiation beam to receiving nine radiation beams. For example, the location of the photoresist 121 corresponding to the area enclosed by the off cell 320B4 will only receive one radiation beam when radiation is applied according to the on cell 320A4. Conversely, the area of ​​the centrally located photoresist 321 corresponding to the area enclosed by the on cell 320A5 will receive nine overlapping radiation beams when radiation is applied according to the on cell 320A5 and then according to the eight on cells 320A (not shown) that surround the on cell 320A5.

[0048] The percentage of on cells 320A out of the total number of unit cells in a given pattern (e.g., first pattern 310) can vary widely. Holding other factors constant for radiation applied to the same photoresist layer, a pattern with a higher percentage of on cells 320A can generally result in photoresist modified to a greater depth than a pattern with a lower percentage of on cells 320A when radiation is applied according to the corresponding respective pattern. Although the percentage of on cells 320A out of the total number of unit cells 320 can be any number between 0% and 100%, some non-limiting examples of the percentage of on cells 320A out of the total number of unit cells 320 that may be used in a pattern include a percentage between about 25% and about 50%, a percentage between about 50% and about 75%, and a percentage between about 75% and about 95%.

[0049] Although the entire first area 301 is exposed to radiation, not all of the first area 301 is exposed to the same amount of radiation. The first pattern 310 is used to control how much radiation different portions of the photoresist 121 in the first area 301 receive. For example, the first portion 311 and the third portion 313 of the first pattern 310 occupied by a plurality of off cells 320B reduce the amount of radiation that would have been received by the first area 301 if the first pattern 310 contained only on cells 320A. The percentage of off cells 320B out of the total number of unit cells 320 in the radiation pattern (e.g., first pattern 310) can be used as a way to control how much radiation an area (e.g., first area 301) receives. Additionally, the placement of off cells 320B in the radiation pattern can be used as a way to control how much radiation a particular portion of an area receives compared to other portions of the area.

[0050] The amount of radiation that a particular portion of the photoresist receives relates to how much that particular portion of the photoresist is ultimately altered by that radiation. For example, photoresist portions that receive a greater amount of radiation are generally altered to a greater depth than other photoresist portions that receive less radiation. Thus, a radiation pattern (e.g., first pattern 310) can be used to control the depth to which the photoresist is altered in a given area (e.g., first area 301) and to vary the depth to which the photoresist is altered across a given area (see the description of FIG. 5, discussed below). Additionally, different radiation patterns can be used to form areas with photoresist altered to different depths, which can ultimately result in structures (e.g., vias) of different depths and / or shapes being formed on the substrate. An example of a different radiation pattern is described below with reference to FIG. 3C.

[0051] Figure 3C illustrates a top view of a second radiation pattern 360, according to one embodiment. Radiation can be directed to second areas 351 according to the second radiation pattern 360 to form second modified portions 350 of the photoresist 121 shown in Figure 3A. Portions of the second pattern 360 can correspond to portions of the second areas 351, so some portions of the second pattern 360 are also referred to as portions of the second areas 351.

[0052] The second radiation pattern 360 is the same as the first radiation pattern 310, except that the sizes of the ring-shaped portions 311-314 in the second pattern 360 are different from those in the first pattern 310. For example, in the second pattern 360, the first portion 311 and the third portion 313 of the off-cell 320B are smaller than the corresponding portions 311, 313 in the first pattern 310. Furthermore, in the second pattern 360, the second portion 312 and the fourth portion 314 of the on-cell 320A are larger than the corresponding portions 312, 314 in the first pattern 310. Thus, in the second pattern 360, the percentage of the on-cell 320A in the total number of unit cells 320 in the second pattern 360 is larger than that in the first pattern 310.

[0053] Due to the larger percentage of on-cells 320A in the second pattern 360 compared to the first pattern 310, if all other operating parameters for radiation (e.g., radiation intensity, duration, shot multiplicity, duty cycle, etc.) are held constant when applying both radiation patterns 310, 360, a larger amount of radiation is directed toward portions of the second area 351 when using the second pattern 360 compared to when using the first pattern 310. This larger amount of radiation directed toward portions of the second area 351 can modify portions of the photoresist in the modified portion 350 to a greater depth than the photoresist in the modified portion 300. Thus, the different patterns 310, 360 show how different areas of the photoresist can be modified to different depths, which ultimately allows for the formation of structures (e.g., vias) of different depths and / or shapes. Depending on these patterns, different radiation patterns applied to different areas of the photoresist can result in modified portions of the photoresist having different maximum depths and / or different depths across corresponding portions of those areas.

[0054] The radiation pattern can also be tailored to produce structures of different shapes. For example, radiation can be reduced towards the edges of the pattern to produce structure sidewalls with less slope. Conversely, a pattern that requires substantially constant radiation from center to edge, or a pattern that requires greater radiation at the edges compared to the center, can be used to produce structures with steeper sidewalls due to the radiation.

[0055] 4 is a process flow diagram of a method 1000 of modifying different areas of a photoresist layer 121 on a substrate 120 with different radiation patterns, according to one embodiment. Method 1000 is described with reference to FIGS. 1-3C. Controller 122 (see FIG. 1) may execute a program stored in a memory to perform some or all of method 1000. Method 1000 begins at block 1002.

[0056] In block 1002 , the substrate 120 is placed on the stage 114 .

[0057] In block 1004 , the stage 114 is moved below the processing unit 106 so that one or more of the multiple image projection systems 200 can direct radiation toward the photoresist layer 121 on the substrate 120 .

[0058] At block 1006, a first plurality of radiation beams are directed to a first area 301 of a photoresist 121 on the substrate 120 using the first pattern 310 to form a first modified portion 300. A plurality of mirrors of one or more of the plurality of spatial light modulators 210 may be used to form a plurality of on-cells 320A and a plurality of off-cells 320B of the first pattern 310 such that the first plurality of radiation beams may be directed to the first area 301 according to the first pattern 310. In some embodiments, there are a sufficient number of mirrors in the spatial light modulator 210 such that a separate mirror may be used for each unit cell 320 of the first pattern 310. In other embodiments, some mirrors of the plurality of mirrors of the spatial light modulator 210 may be reused for two or more unit cells 320 of the pattern as the stage 114 moves the substrate 120 to different positions, such that the mirrors may generate the first pattern 310 over time as the stage 114 moves. In some embodiments, the angles of some of the mirrors of the spatial light modulator can be adjusted so that they can be used for more than one unit cell 320 of the first pattern 310.

[0059] At block 1008, a second plurality of radiation beams are directed to a second area 351 of the photoresist 121 on the substrate 120 using the second pattern 360 to form a second modified portion 350. A plurality of mirrors of one or more of the plurality of spatial light modulators 210 may be used to form a plurality of on-cells 320A and a plurality of off-cells 320B of the second pattern 360 such that radiation may be directed to the second area 351 according to the second pattern 360. In some embodiments, there are a sufficient number of mirrors in the spatial light modulator 210 such that a separate mirror may be used for each unit cell 320 of the second pattern 360. In other embodiments, some of the mirrors of the plurality of mirrors of the spatial light modulator 210 may be reused using a method similar to that described above with respect to block 1006. In some embodiments, blocks 1006, 1008 are performed at separate times, while in other embodiments, blocks 1006, 1008 may be performed simultaneously.

[0060] As noted above, the second pattern 360 has a higher percentage of on-cells 320A compared to the first pattern 310. This higher percentage results in portions of the photoresist 121 in the second portion 350 being modified (e.g., the solubility of the photoresist in a photoresist developer is altered) to a greater depth compared to the corresponding portions of the first modified portion 300 when the same amount and type of radiation is emitted from each of the on-cells 320A of the corresponding respective patterns 310, 360. Although only two radiation patterns 310, 360 are directed at the substrate 120 during the method 1000, the method 1000 can continue to direct radiation using additional patterns (not shown) or the same patterns 310, 360 at other areas of the photoresist 121 such that other structures of various depths and / or shapes can be formed.

[0061] Method 1000 may also be performed on more than one region of a single area such that different radiation patterns may be applied to more than one region of a single area, thereby tailoring the depth and / or shape of the altered photoresist across the single area. An example of applying two different radiation patterns to two regions within a single area is described in more detail below with reference to FIG. 5D.

[0062] 5A is a top view of a substrate 120 according to another embodiment. In FIG. 5A, the substrate 120 includes a photoresist layer 121, a first modification 500, a second modification 550, and a third modification 570. The modifications 500, 550, 570 are modifications of the photoresist layer 121 (also called the first layer) on the substrate 120. The first modification 500 is formed by directing a first radiation pattern 510 (see FIG. 5B) to a first area 501 of the photoresist layer 121. The second modification 550 is formed by directing a second radiation pattern 560 (see FIG. 5C) to a second area 551 of the photoresist layer 121. The third modified portion 570 is formed by directing a third radiation pattern 580 to a first region 571A of the third area 571 of the photoresist layer 121 and directing a fourth radiation pattern 590 (see FIG. 5D) to a second region 571B of the third area 571 of the photoresist layer 121.

[0063] The modified portions 500, 550, 570 are physically altered relative to unaltered portions of the photoresist layer 121. The modified portions 500, 550, 570 are physically altered by radiation directed at corresponding first areas 501, second areas 551, and third areas 571. For example, the radiation may alter the solubility of the photoresist layer 121 in areas 501, 551, 571 to allow application of a photoresist developer to the substrate 120, thereby allowing structures (e.g., vias) to be formed from the modified portions 500, 550, 570.

[0064] Figure 5B illustrates a top view of a first radiation pattern 510, according to one embodiment. Radiation can be directed to a first area 501 according to the first radiation pattern 510 to form the first modified portion 500 of Figure 5A. Portions of the first pattern 510 can correspond to portions of the first area 501, so some portions of the first pattern 510 are also referred to as portions of the first area 501.

[0065] The first radiation pattern 510 is similar to the patterns 310, 360 described above with reference to Figures 3B and 3C, except for a different arrangement of the on-cells 320A and off-cells 320B. Although not required, the unit cells 320 of the first pattern 510 may have the same size as the unit cells 320 of the patterns 310, 360. Furthermore, although not required, each radiation beam applied according to the first pattern 510 may be incident on a portion 305 having the same size as the portion 305 described above with reference to Figures 3B and 3C. An exemplary portion 3051 is shown in the upper right corner of the first pattern 510, with the center of the portion 3051 focused on the on-cell 320A1.

[0066] In the first pattern 510, the shaded areas include and are completely filled with the on cells 320A, and the non-shaded areas include and are completely filled with the off cells 320B. The on cells 320A are arranged in a row extending in the Y direction. Similarly, the off cells 320B are arranged in a row extending in the Y direction. When the on cells 320A are arranged in a row, the on cells 320A are arranged along a line including consecutive on cells 320A and no intervening off cells 320B. When the off cells 320B are arranged in a row, the off cells 320B are arranged along a line including consecutive off cells 320B and no intervening off cells 320A.

[0067] Using a pattern having groupings of consecutive on-cells 320A and consecutive off-cells 320B can help increase the processing speed of applying the radiation pattern to a substrate. Using consecutive on-cells 320A and consecutive off-cells 320B can reduce processing demands on components of the lithography system 100, such as the rasterizer. When a pattern that does not include large groupings of consecutive on-cells 320A or off-cells 320B is used (e.g., a checkerboard pattern), the processing speed of applying the radiation pattern is often slower than the processing speed of applying a radiation pattern that has more groupings of consecutive on-cells 320A and consecutive off-cells 320B, such as patterns 510, 560, 580, and 590 described with reference to Figures 5B-5D.

[0068] Although all of the on-cells 320A and off-cells 320B are included in a line of consecutive on-cells 320A and off-cells 320B, this is not necessary to achieve increased processing speed. Processing speed can be increased by increasing the percentage of on-cells 320A and / or off-cells 320B in a corresponding line of consecutive on-cells 320A and off-cells 320B (e.g., 25%, 50%, 75%, 90%, 95%, 99% or more). Similarly, processing speed can also be increased by increasing the number of consecutive on-cells 320A and consecutive off-cells 320B in these lines of consecutive unit cells 320 (e.g., at least 10 consecutive cells, at least 50 consecutive cells, at least 100 consecutive cells, at least 250 consecutive cells, at least 500 consecutive cells, at least 1000 consecutive cells).

[0069] Figure 5C illustrates a top view of a second radiation pattern 560, according to one embodiment. Radiation can be directed to a second area 551 according to the second radiation pattern 560 to form the second modified portion 550 of Figure 5A. Portions of the second pattern 560 can correspond to portions of the second area 551, so some portions of the second pattern 560 are also referred to as portions of the second area 551.

[0070] The second radiation pattern 560 is the same as the first radiation pattern 510, except that the second radiation pattern 560 includes consecutive on-cells 320A and consecutive off-cells 320B arranged in rows extending in the X-direction, rather than in columns extending in the Y-direction as described above with reference to FIG. 5B. Depending on the type of equipment (e.g., lithography system 100) being used, the substrate being used, or the location of the area receiving the radiation pattern on a given substrate, it may be useful to arrange the line of consecutive unit cells 320 in rows rather than in columns. For example, in some equipment, it may be more beneficial to have the line of consecutive unit cells 320 parallel or perpendicular to the direction of movement of the substrate support (e.g., stage 114) to reduce the processing time of applying the radiation pattern.

[0071] Other arrangements of consecutive on-cells 320A and consecutive off-cells 320B may also be useful. For example, in one embodiment, consecutive on-cells 320A and consecutive off-cells 320B may be arranged along diagonal lines of consecutive on-cells 320A and consecutive off-cells 320B (e.g., 45 degree diagonal lines or any angle other than a straight line or vertical line). These lines may be diagonal to an edge of a pattern (e.g., an edge of the first pattern 510 shown in FIG. 5B), an edge of a feature printed on a substrate, or an edge of a substrate (e.g., an edge of the rectangular substrate 120 shown in FIG. 1A). For example, in some instances, using diagonal lines of consecutive on-cells 320A and consecutive off-cells 320B that are diagonal to a feature printed on a substrate may produce a better product (i.e., the pattern on the product may be less noticeable to a user of the end product, such as a display on an electronic device). A random pattern of on-cells 320A and off-cells 320B may also be beneficial in producing a better product (i.e., the pattern on the product may be less noticeable to a user of the end product, such as a display on an electronic device).

[0072] 5D illustrates a top view of the third radiation pattern 580 and the fourth radiation pattern 590 according to one embodiment. The radiation can be directed to the third area 571 according to the third radiation pattern 580 and the fourth radiation pattern 590 to form the third modified portion 570 of FIG. 5A. Some portions of the third pattern 580 and the fourth pattern 590 can correspond to portions of the third area 571, and therefore some portions of the third pattern 580 and the fourth pattern 590 are also referred to as portions of the third area 571. Similar to the patterns described above, the hatched areas of the patterns 580, 590 can also include and be completely filled by the on-cells 320A, while the unhatched areas of the patterns 580, 590 can also include and be completely filled by the off-cells 320B. Additionally, each on-cell 320A of the patterns 580, 590 can identify a portion 305 around which the center of radiation is focused according to the corresponding respective pattern.

[0073] 5D provides an example of how two radiation patterns 580, 590 can be directed into a single area 571. Directing more than one pattern into a single area (e.g., the third area 571) can be used to vary the depth to which portions of the photoresist 121 are altered across the single area. For example, the fourth pattern 590 includes a higher percentage of the shaded area (i.e., the area identifying the portion where the center of the radiation beam is focused) than the third pattern 580, and therefore can alter portions of the photoresist 121 in the second region 571B to a deeper depth than the photoresist 121 in the first region 571A.

[0074] Directing more than one pattern into a single area (e.g., the third area 571) can also be used to vary the shape of the portion of the photoresist 121 that is altered. For example, the first area 571A includes a sidewall 572A connected to a sidewall 572B of the second area 571B. The unit cells of the top row of the third pattern 580 correspond to the portion of the radiation that is directed into the section that includes the sidewall 572A of the first area 571A. This top row of the third pattern 580 includes seven off-cells 320B. Meanwhile, the corresponding top row of the fourth pattern 590, which corresponds to the portion of the radiation that is directed into the section that includes the sidewall 572B of the second area 571B, does not include any off-cells 320B. Because this top section of the fourth pattern 590 has fewer off cells 320B than the corresponding section of the third pattern 580, the top section of the second region 571B can receive more radiation than the corresponding section of the first region 571A. In some embodiments, the increased radiation of the top portion of the second region 571B compared to the top portion of the first region 571A can cause the sidewall 572B to have a steeper slope than the sidewall 572A.

[0075] For all of the radiation patterns described herein, at least some of the off-cells of the plurality of off-cells 320B are disposed between some of the on-cells of the plurality of on-cells 320A. By disposing the off-cells 320B between some of the on-cells of the plurality of on-cells 320A in this manner, the radiation in the pattern can be modified, thereby controlling the depth and shape of the photoresist modified by the radiation.

[0076] Although the above patterns have been described using unit cells 320 of the same size, it is possible to adjust the size of the unit cells 320 for different radiation patterns on one or more substrates, or within a single pattern on a substrate. For example, a unit cell having a larger area can be used in areas where the radiation is creating structures that vary less in shape and / or depth. Conversely, a unit cell having a smaller area can be used in areas where the radiation is creating structures that vary more in shape and / or depth. Using unit cells with smaller areas can allow for more precise control of the structures being created. Conversely, larger unit cells can reduce processing time, since the number of beams directed to the substrate is directly proportional to the number of unit cells, and therefore inversely proportional to the size (i.e., area) of the unit cells that do not overlap each other.

[0077] Additionally, the size of the portion (see, e.g., portion 305 in FIG. 3B) into which the radiation is directed can also be adjusted for different radiation patterns on one or more substrates, or within a single pattern on a substrate. Larger portions can be used to reduce processing time, while smaller portions can allow for more precise control of the depth and shape of the structures being formed by the radiation.

[0078] The above described embodiments provide a system and method for forming structures of different depths and shapes in a single exposure (i.e., a single pass of the substrate under the processing unit 106 shown in FIG. 1). The image projection system 200 in the processing unit 106 can direct overlapping portions 305 of radiation to the photoresist 121 according to a pattern being applied (e.g., the first pattern 310 in FIG. 3B). The overlapping portions of radiation are directed according to a layout of the on-cells 320A and off-cells 320B of the applied pattern. Each applied radiation beam is focused at its center on an area of ​​the photoresist corresponding to one of the on-cells 320A of the multiple on-cells 320A of the applied pattern. The size of the unit cell 320 is smaller than the size of the applied radiation, which allows for precise control of the amount of radiation being applied to each area of ​​the unit cell size of the photoresist described above. This precise control allows for fine control over the depth and shape of the structures being formed by the radiation, and for such depth and shape to be completed in a single pass of the substrate under the lithography system.

[0079] To form structures having different depths and shapes using conventional lithography systems with conventional masks, multiple passes of the substrate under the writable area of ​​the lithography system are required. Multiple passes of the substrate under the writable area of ​​the lithography system reduce throughput. Thus, the above-described systems and methods capable of forming structures of different depths and / or shapes in a single pass of the substrate provide a significant improvement over techniques using conventional lithography systems.

[0080] While the foregoing is directed to examples of the disclosure, other and further examples of the disclosure may be devised without departing from the basic scope of the examples of the disclosure, the scope of which is determined by the following claims.

Claims

1. Directing a plurality of beams of radiation onto a first area of ​​a first layer on a substrate, each beam being incident on a different one of a plurality of portions within the first area. Including, Each portion has an area of ​​a first size; the plurality of radiation beams are directed at the first area according to a first pattern; the first pattern includes a plurality of unit cells including a plurality of on-cells and a plurality of off-cells; each unit cell having an area smaller than the first size; the plurality of ON cells identify a location within the first area where a center of a radiation beam of the plurality of radiation beams converges; the plurality of off-cells identifying locations within the first area where none of the plurality of radiation beams converge at a center; method.

2. The method of claim 1 , wherein at least some of the off-cells of the first pattern are disposed between some of the on-cells of the first pattern.

3. The method of claim 1 , wherein the entire first area is illuminated by at least some of the plurality of radiation beams.

4. The method of claim 1 , wherein the first layer is a photoresist layer.

5. 2. The method of claim 1, wherein a percentage of on-cells in the first pattern is from about 75% to about 95% of a total number of unit cells in the first pattern.

6. 2. The method of claim 1, wherein a percentage of on-cells in the first pattern is from about 50% to about 75% of a total number of unit cells in the first pattern.

7. 2. The method of claim 1, wherein a percentage of on-cells in the first pattern is from about 25% to about 50% of a total number of unit cells in the first pattern.

8. 2. The method of claim 1, wherein in the first pattern, at least 75% of the on-cells are arranged along a line containing at least 10 consecutive on-cells.

9. 9. The method of claim 8, wherein within the first pattern, at least 75% of the off-cells are arranged along a line containing at least 10 contiguous off-cells.

10. directing a first plurality of beams of radiation onto a first area of ​​a first layer on a substrate, each beam being incident on a different one of a plurality of portions within the first area; directing a second plurality of beams of radiation onto a second area of ​​the first layer on the substrate, each beam being incident on a different one of the portions within the second area; Including, each portion of the first area and the second area having an area of ​​a first size; the first plurality of radiation beams are directed to the first area according to a first pattern; the second plurality of radiation beams are directed onto the second area according to a second pattern; the first pattern and the second pattern each include a plurality of unit cells, each including a plurality of on-cells and a plurality of off-cells; a unit cell of each of the first pattern and the second pattern has an area smaller than the first size; the plurality of on-cells of the first pattern identify locations within the first area where a center of a radiation beam of the first plurality of radiation beams converges; the plurality of off-cells of the first pattern identify locations within the first area where no radiation beam of the first plurality of radiation beams converges at its center; the plurality of on-cells of the second pattern identify locations within the second area where a center of a radiation beam of the second plurality of radiation beams converges; the plurality of off-cells of the second pattern identify locations within the second area where none of the radiation beams of the second plurality of radiation beams converge at their centers. method.

11. The method of claim 10 , wherein the first pattern comprises a different arrangement of on-cells and off-cells than the second pattern.

12. the first pattern includes a first percentage of on-cells out of a total number of unit cells of the first pattern; the second pattern includes a second percentage of on-cells out of a total number of unit cells of the second pattern; the first percentage is different from the second percentage; The method of claim 10.

13. The method of claim 10 , wherein the first layer is a photoresist layer.

14. 14. The method of claim 13, wherein the photoresist layer in the first areas is physically altered to a maximum depth that is different from a maximum depth to which the photoresist layer in the second areas is physically altered.

15. The method of claim 10 , wherein the first area is greater than the second area.

16. The method of claim 10 , wherein for the first pattern and the second pattern, at least some of the off-cells are disposed between some of the on-cells.

17. directing a first plurality of radiation beams into a first region of a first area of ​​a first layer on a substrate, each beam of the first plurality of beams being incident on a different one of a plurality of portions within the first region; and Directing a second plurality of radiation beams into a second region of the first area, each beam of the second plurality of beams being incident on a different one of a plurality of portions within the second region. Including, each portion of the first region and the second region having an area of ​​a first size; the second plurality of radiation beams are directed onto the first regions of the first area according to a first pattern; the second plurality of radiation beams are directed onto second regions of the first area according to a second pattern; the first pattern and the second pattern each include a plurality of unit cells including a plurality of on-cells and a plurality of off-cells; a unit cell of each of the first pattern and the second pattern has an area smaller than the first size; the plurality of on-cells of the first pattern identify locations within the first region where a center of a radiation beam of the first plurality of radiation beams converges; the plurality of off-cells of the first pattern identify locations within the first region where no radiation beam of the first plurality of radiation beams converges at its center; the plurality of on-cells of the second pattern identify locations within a second region where a center of a radiation beam of the second plurality of radiation beams converges; the plurality of off-cells of the second pattern identify locations within the second region where none of the radiation beams of the second plurality of radiation beams converge at their centers. method.

18. 20. The method of claim 17, wherein for the first region and the second region, at least some of the off-cells are disposed between some of the on-cells.

19. The method of claim 17 , wherein the entire first area is illuminated by at least a portion of the first plurality of radiation beams or the second plurality of radiation beams.

20. The method of claim 17 , wherein the first layer is a photoresist layer.

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