Lithographic apparatus, patterning system and method for a patterned layered structure

Abstract

Embodiments of the present case include a lithography apparatus, a patterning system, and a method for patterning a layered structure. The patterning system includes an image forming device and a reaction layer. The patterning system allows for the creation of a lithography pattern in a single operation. The lithography apparatus includes the patterning system and an optical system. The lithography apparatus uses light of multiple wavelengths together with the image forming device to create multiple color patterns on the reaction layer. The patterning method includes exposing the reaction layer to light of multiple wavelengths. Depending on the wavelength of the light emitted to different regions, the light reacts differently with different regions of the reaction layer. The methods and apparatuses disclosed in the present case only require one image forming device and one lithography operation.

Description

Technical Field

[0001] Embodiments of the present case relate to an apparatus and a method, and more particularly, to a lithography apparatus, a patterning system, and a method for patterning a layered structure.

[0002] Description of the Prior Art

[0003] Lithography technology plays an important role in the manufacture of integrated circuit (IC) chips. Continuous improvements in optical projection lithography technology have enabled the printing of ever finer integrated circuit features. In turn, this has enabled the integrated circuit industry to produce more powerful and cost-effective semiconductor devices.

[0004] In the field of optical lithography processing, a photosensitive material is applied to a substrate, and the photosensitive material is then dried. Using an exposure tool in the form of a light source or radiation source, the substrate coated with the photosensitive material is exposed via a mask in an appropriate geometric pattern. After exposure, the wafer is processed to develop the mask image transferred onto the photosensitive material. These mask patterns are then used to form the device features of the circuit.

[0005] When the pattern resolution requirements for a single design layer exceed the capabilities of the exposure tool, these limitations can be addressed by dividing the pattern into multiple lithography steps. The drawback is that many photolithography patterns use multiple masks in multiple steps, which requires retrieving the substrate after the first patterning and adding a second mask, thus slowing down the lithography process and increasing user costs. Additionally, the step of placing the second mask requires careful alignment. Alignment errors can result in misaligned patterns, wasting resources and requiring additional time for correction.

[0006] Therefore, improved lithography methods are needed, and reducing the number of patterning steps required would be valuable. Summary of the Invention

[0007] Embodiments of the present case include a lithography apparatus, a patterning system, and a method for patterning a layered structure. The apparatus and method provided by the present case can perform a lithography process with enhanced resolution in a single lithography operation without the need for multiple photoresist applications, development steps, etching processes, or the need for multiple masks.

[0008] In one embodiment, a lithography apparatus is provided, the lithography apparatus comprising: a substrate support configured to support a layered structure; a light source system capable of emitting light of two or more wavelengths; and an image forming device capable of receiving light of two or more wavelengths generated by the light source system and generating two or more light images at two or more wavelengths received from the light source system.

[0009] In another embodiment, a patterning system is provided, the patterning system including an image forming device and a photosensitive reaction layer. The reaction material includes a first region and a second region. The image forming device is configured to allow light of a first wavelength to reach the first region, and the image forming device is configured to allow light of a second wavelength to reach the second region.

[0010] In yet another embodiment, a method of patterning a layered structure is provided, the method including the steps of: disposing a reaction layer over the layered structure, and exposing the reaction layer to light of multiple wavelengths by an image forming device. The reaction layer includes a reaction material. The reaction material includes a first region and a second region. The step of exposing the reaction layer includes exposing the first region to light of a first wavelength and exposing the second region to light of a second wavelength. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Thus, the above-described features of the present case can be understood in detail, and the present case can be described in more detail by referring to the embodiments. The detailed description of the present case is as briefly described above, and some of the embodiments are shown in the drawings. However, it should be noted that the drawings only illustrate exemplary embodiments and should not be regarded as a limitation of the scope, and other equivalent embodiments are allowed.

[0012] Figure 1 The figure shows a lithographic apparatus according to one or more embodiments described and discussed herein.

[0013] Figure 2 is a flow chart of operations of a method for patterning a layered structure according to one or more embodiments described and discussed herein.

[0014] Figure 3A The figure shows a top view of a portion of a reaction layer according to one or more embodiments described and discussed herein.

[0015] Figure 3B The figure shows a cross-sectional side view of a portion of a reaction layer according to one or more embodiments described and discussed herein.

[0016] Figure 3C The figure shows a top view of a portion of a reaction layer according to one or more embodiments described and discussed herein.

[0017] Figure 3D The figure shows a cross-sectional side view of a portion of a reaction layer according to one or more embodiments described and discussed herein.

[0018] Figure 3E The figure shows a top view of a portion of a reaction layer according to one or more embodiments described and discussed herein.

[0019] Figure 3FThe figure shows a cross-sectional side view of a part of a reaction layer according to one or more embodiments described and discussed in this case.

[0020] Figures 4A to 4C The figure shows light of a first wavelength incident on a reaction layer according to one or more embodiments described and discussed in this case.

[0021] Figures 5A to 5B The figure shows a cross-sectional side view of a part of a workpiece including a reaction layer at different stages of processing according to one or more embodiments described and discussed in this case.

[0022] Figure 5C The figure shows according to one or more embodiments described and discussed in this case Figure 5B a top view of a part of the workpiece in.

[0023] Figure 6 The figure shows a top view of a part of a workpiece including a reaction layer at one processing stage according to one or more embodiments described and discussed in this case.

[0024] For ease of understanding, the same reference numerals are used as far as possible to denote the same elements common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. Detailed Description

[0025] Embodiments of this case include a lithographic apparatus, a patterning system, and a method of patterning a layered structure. The patterning system includes a multi-wavelength light source, an image forming device, and a reaction layer having multiple behaviors corresponding to light of multiple wavelengths. The patterning system allows two or more different lithographic patterns to be created at two or more different wavelengths. The lithographic apparatus includes the patterning system and an optical system. The lithographic apparatus uses light of multiple wavelengths that can be discretely directed by the image forming device to form multiple patterns and / or images on the reaction layer. The patterning method includes exposing the reaction layer to light of multiple wavelengths. Light of different wavelengths is exposed on different regions of the reaction layer. Different regions of the reaction layer react differently depending on the wavelength of the exposed light. The methods and apparatuses disclosed in this case require only one lithographic operation. In addition, the use of a single illumination operation reduces the need to align multiple masks in multiple steps, thereby reducing the lithography time. Embodiments of this case can be used in but are not limited to a lithographic apparatus configured to provide light of multiple wavelengths to two different parts of a reaction layer.

[0026] Figure 1The figure shows a lithographic apparatus 100 according to one or more embodiments described and discussed herein. The lithographic apparatus 100 is configured to project images of multiple different wavelengths onto a underlying layered structure 117. The lithographic apparatus 100 can be any lithographic tool used in the art, such as but not limited to a mask-based lithographic tool, or a maskless (direct write) lithographic tool with a raster beam architecture of a multi-beam array architecture.

[0027] As shown, the lithographic apparatus 100 includes an optical system 103, a patterning system 150, a substrate support 116, and a controller 190. The substrate support 116 is configured to support the layered structure 117. The substrate support 116 is attached to a support actuator 118. The support actuator 118 is configured to move the substrate support 116 to any position in three-dimensional space. For example, the substrate support 116 is lowered to receive the layered structure 117 from a robot (not shown) outside the lithographic apparatus 100.

[0028] The layered structure 117 serves as a workpiece for various semiconductor devices, printed circuit boards, flat panel displays, and / or other MEMS, optical devices, and the like. As shown, the layered structure 117 includes a substrate 115. The substrate 115 can be any substrate used in the art. For example, the substrate 115 includes a semiconductor material, such as silicon (Si), germanium (Ge), silicon germanium (SiGe), and / or III-V semiconductors, such as gallium arsenide (GaAs). In another example, the substrate 115 includes a transparent material, such as glass and / or plastic. The substrate 115 can have any number of insulating layers, semiconductor layers, or metal layers on the substrate 115.

[0029] The optical system 103 is configured to project and control multiple discrete wavelength images of light onto the underlying layered structure 117. As shown, the optical system 103 includes one or more projection lenses 105 and a light source system 130. The light source system 130 is configured to emit light of multiple wavelengths, such as two wavelengths. The wavelengths emitted by the light source system can be any wavelength in the electromagnetic spectrum, such as ultraviolet (UV), visible light, or infrared (IR). According to one or more embodiments described and discussed herein, the light source system emits light having a first wavelength of about 240 nm to about 250 nm (e.g., deep ultraviolet (DUV) light) and light having a second wavelength of about 300 nm to about 375 nm (e.g., UV or i-line light). The wavelengths of the light are selected by those skilled in the art based on the photosensitive reactants within the reaction layer, as described in more detail below.

[0030] The light source system 130 may include a single light source or multiple light sources, e.g., a first light source and a second light source. According to one or more embodiments described and discussed herein, the first and second light sources are configured to emit light of first and second wavelengths. According to one or more embodiments described and discussed herein, the light source system 130 includes a single light source that sequentially emits light of these wavelengths. The light source can be any light source used in the art, such as a light-emitting diode (LED), a laser diode, a vertical-cavity surface-emitting laser diode (VCSEL), an excimer laser (e.g., a krypton fluoride (KrF) or an argon fluoride (ArF) laser), a frequency-doubled laser (e.g., a neodymium-doped yttrium aluminum garnet (Nd:Y3A l5 O 12 ) [Nd:YAG] laser) with a frequency that is three times 353 nm or four times 266 nm, a conventional mercury-halogen lamp having a band-pass filter that alternates between approximately 365 nm and approximately 405 nm, or other combinations of light sources that match the behavior of multiple photosensitive reactants within the reaction layer.

[0031] One or more projection lenses 105 can be any projection lenses used in the art (e.g., spherical, cylindrical) and can include any suitable layer or coating on the one or more projection lenses 105. The optical system 103 may further include a beam splitter (not shown) to focus the light source system 130 onto the underlying patterning system 150. According to one or more embodiments described and discussed herein, the beam splitter focuses the light emitted from multiple light sources onto a single projection lens, and the projection lens focuses the light onto the patterning system 150. According to one or more embodiments described and discussed herein, the light emitted from multiple light sources is focused by one or more projection lenses 105, and the projection lens focuses the light onto the patterning system 150.

[0032] The patterning system 150 is configured to pattern a desired pattern onto the layered structure 117. As shown, the patterning system 150 includes an image forming device 120 and a reaction layer 110. The image forming device 120 can be any device used in the art for lithography. The image forming device 120 is configured to allow light to pass through in a predetermined area. The image forming device 120 can include any mask used in the art for lithography, such as a photomask, a virtual mask, and / or a digital mask (e.g., a spatial light modulator, such as a digital micromirror device (DMD)). The image forming device 120 can include any number of masks or combinations of masks, e.g., one mask having two different color-blocking patterns or two photomasks.

[0033] The image forming device 120 is operable to receive light of two or more wavelengths generated by the light source system 130 and generate two or more light images having the two or more received wavelengths. The image forming device 120 may include any number of regions, and each region is configured to allow light to be incident on a specific portion of the reaction layer 110. In some embodiments, the image forming device 120 includes a plurality of photomasks, and each photomask is configured to receive light of a different wavelength. In some embodiments, the image forming device 120 includes a multicolor mask, and this multicolor mask absorbs certain wavelengths at certain portions of the mask while allowing other wavelengths to be transmitted at the same portions of the mask. In some embodiments, the image forming device 120 includes a plurality of photomask layers, and each photomask layer is configured to transmit light of a different wavelength.

[0034] According to one or more embodiments described and discussed herein, the image forming device 120 includes one or more digital micromirror devices (DMDs). The one or more DMDs are configured to form virtual masks. In some embodiments, a plurality of color images are combined to form one or more composite images.

[0035] In some embodiments, one or more additional projection lenses (not shown) are disposed between the image forming device 120 and the reaction layer 110. The one or more additional projection lenses further focus the light passing through the image forming device 120 onto the reaction layer 110 disposed below the image forming device.

[0036] In one or more embodiments, the lithography apparatus 100 includes: an image forming device 120 including two photomasks; a light source system 130 including two light sources; a beam splitter; and a projection lens, and the beam splitter focuses the light emitted from the two light sources onto these projection lenses.

[0037] In one or more embodiments, the lithography apparatus 100 includes: an image forming device 120 including two photomasks; a light source system 130 including two light sources; two projection lenses, and the light emitted from the two light sources is respectively focused onto one of these projection lenses.

[0038] In one or more embodiments, the lithography apparatus 100 includes: an image forming device 120 including two virtual masks (e.g., two DMDs); a light source system 130 including two light sources; a beam splitter; and a projection lens, and the beam splitter focuses the light emitted from the two light sources onto this projection lens.

[0039] In one or more embodiments, a lithographic apparatus 100 includes: an image forming device 120 including two virtual masks (e.g., two DMDs); a light source system 130 including two light sources; two projection lenses, and light emitted from the two light sources is respectively focused onto one of these projection lenses.

[0040] In one or more embodiments, a lithographic apparatus 100 includes: an image forming device 120 including a virtual mask (e.g., a DMD); a light source system 130, and the light source system includes a single light source that sequentially emits light of multiple wavelengths.

[0041] In one or more embodiments, a lithographic apparatus 100 includes: an image forming device 120 including a multicolor mask; an optical device 104; a light source system 130, and the light source system includes a single light source that sequentially emits light of multiple wavelengths.

[0042] A controller 190 is configured to control and automate the lithographic apparatus 100. As shown, the controller 190 includes a central processing unit (CPU) (not shown), a memory (not shown), and auxiliary circuitry (or I / O) (not shown). The CPU is one of any form of computer processor used in an industrial setting to control various programs and hardware (e.g., pattern generators, motors, and other hardware), and to monitor processes (e.g., processing time and substrate positioning or location). The memory (not shown) is connected to the CPU and is one or more types of readily available memory, such as random access memory (RAM), read only memory (ROM), floppy disks, hard disks, or any other form of local or remote digital storage. Software instructions and data can be encoded and stored in the memory to be used to instruct the CPU. The auxiliary circuitry (not shown) is also connected to the CPU to assist the processor in a conventional manner. The auxiliary circuitry includes conventional caches, power supplies, clock circuits, input / output circuits, subsystems, and the like. Programs (or computer instructions) readable by the controller 190 determine which tasks the lithographic apparatus 100 can perform.

[0043] The reaction layer 110 is configured to react to light of different wavelengths. In some embodiments, different portions of the reaction layer 110 can be configured to react to light of different wavelengths. According to one or more embodiments described and discussed herein, the reaction layer 110 has a first region configured to react to light of a first wavelength and a second region configured to react to light of a second wavelength. According to one or more embodiments described and discussed herein, the first region and the second region at least partially overlap.

[0044] In other embodiments, the reaction layer 110 comprises a uniform material. In these embodiments, different portions of the reaction layer 110 are exposed to light of different wavelengths. Thus, different portions of the reaction layer 110 (e.g., a first and a second region) have different reactions due to the light of the wavelength to which the portion is exposed, even though the material of each portion is the same. According to one or more embodiments described and discussed herein, the first region and the second region at least partially overlap.

[0045] The reaction layer 110 can comprise any material that is photosensitive under a specific spectrum. For example, the reaction layer 110 includes a first metal that is more photosensitive at a first wavelength, and the reaction layer 110 includes a second metal that is more photosensitive at a second wavelength. In another example, the reaction layer 110 includes a first polymer that is more photosensitive at a first wavelength, and the reaction layer 110 includes a second polymer that is more photosensitive at a second wavelength.

[0046] The light incident on the reaction layer 110 can have an intensity gradient, such as a Gaussian distribution. Thus, different portions of the reaction layer 110 can receive different doses of light. The material of the reaction layer 110 can change its water solubility according to the dose of the applied light. Thus, depending on the dose of the applied light, the material can have regions that are soluble, partially soluble, or insoluble.

[0047] In some embodiments, the solubility of the material does not change until a processing step is applied to the reaction layer 110, such as a post-exposure bake. The processing step can include heating the reaction layer 110 to a temperature of about 70 °C to about 200 °C for a time of about 10 seconds to about 300 seconds.

[0048] The reaction layer 110 can include one or more photoacid generators (PAGs) and / or photobase generators (PBGs). PAGs include functional groups that generate acids, such as hydrogen and / or protons, after absorbing light of a specific wavelength. Due to photodissociation and / or due to the dissociation of protons during photoassociation (e.g., a cycle), PAGs generate strong acids. PBGs contain functional groups that generate base ions (e.g., amine compounds) after absorbing light of a specific wavelength. PAGs and PBGs can be photosensitive at the same or different wavelengths.

[0049] In addition, PAGs and PBGs that become photosensitive at the same wavelength can have different acid and base formation rates and / or acid-base concentrations. Also, PAGs and PBGs that become photosensitive at the same wavelength can have acid and base formation rates and / or acid-base concentrations that depend on the dose of the absorbed light. Thus, a material that includes both PAGs and PBGs that are sensitive at approximately the same wavelength can have acidic, basic, or neutral regions, depending on the dose of the light and the wavelength of the light applied to the region.

[0050] The solubility of the material can vary with the acidity / alkalinity of the material. For example, the material includes a polymer containing a water-soluble blocker or protecting group. When enough PAG is activated, the soluble group is cleaved or deprotected by acidic molecules, and the acid unwinds the polymer chains of the material, making the material more soluble. If PBG is also activated, the basic molecules will neutralize the acidic molecules, thus protecting the soluble group, the polymer will not unwind, and the material remains insoluble or poorly soluble. PBG can also induce polymer crosslinking in the material, thereby reducing the effectiveness of acid deprotection. Therefore, depending on the dose of light and the wavelength of the light applied, a material including both PAG and PBG that are sensitive at approximately the same wavelength can have regions that are soluble, partially soluble, or insoluble.

[0051] The light incident on the reaction layer 110 can have an intensity gradient, such as a Gaussian distribution. Therefore, different parts of the reaction layer 110 can receive different doses of light. Thus, depending on the dose of light received, different parts of the reaction layer 110 containing both PAG and PBG that are sensitive at the same wavelength can be acidic, basic, or neutral.

[0052] In one or more embodiments, the reaction layer 110 includes a first PAG and a first PBG. The first PAG and the first PBG are photosensitive to light of a first wavelength.

[0053] At a high dose of light of the first wavelength, the basic molecules generated by PBG are more than the acidic molecules generated by PAG, and a high-dose region is generated in the first region. The higher basicity of the high-dose region can make the high-dose region more soluble or less soluble compared to the unreacted first region. Therefore, the high-dose region can be etched away more easily or with more difficulty as the unreacted portion. In some embodiments, the high-dose region has the same solubility as the unreacted portion. According to one or more embodiments described and discussed in this case, the high-dose region has at least about 10% to 20% more basic molecules compared to acidic molecules.

[0054] In one or more embodiments, the high-dose region will have a net base concentration that will not cause deprotection of poly-t-BOC after post-exposure bake, and thus remains insoluble in an aqueous base developer such as tetramethylammonium hydroxide (TMAH).

[0055] At a medium dose of light of the first wavelength, the acidic molecules generated by PAG are more than the basic molecules generated by PBG, and a medium-dose region is generated in the first region. The higher acidity of the medium-dose region can make the medium-dose region more soluble or less soluble compared to the unreacted first region. Therefore, the medium-dose region may be more difficult or easier to etch away as the unreacted portion. According to one or more embodiments described and discussed in this case, the medium-dose region has at least about 10% to 20% more acidic molecules compared to basic molecules.

[0056] In one or more embodiments, the medium dose region has a net acid concentration that will cause net deprotection of poly-t-BOC after post-exposure bake and will be soluble in an aqueous base developer (such as TMAH).

[0057] At low doses of light of the first wavelength, the PAG generates few acidic molecules and the PBG generates few basic molecules, and a low dose region is produced in the first region. The neutrality of the low dose region has approximately the same solubility as the unreacted first region. Thus, the low dose region has approximately the same etch difficulty as the unreacted portion.

[0058] In one or more embodiments, the low dose region will not produce deprotection of poly-t-BOC after post-exposure bake and thus remains insoluble in an aqueous base developer (such as TMAH).

[0059] In one or more embodiments that can be applied in conjunction with the embodiments described below, above, or alone, the first PBG is also photosensitive at light of the second wavelength, while the first PAG is not photosensitive at light of the second wavelength. At high doses of light of the second wavelength, the first PBG generates basic molecules. The higher basicity of the high dose region can make the high dose region more or less soluble compared to the unreacted first region. Thus, the high dose region can be easier or more difficult to etch away to become the unreacted portion. In some embodiments, the high dose region has the same solubility as the unreacted portion.

[0060] In one or more embodiments that can be applied in conjunction with the embodiments described below, above, or alone, the reaction layer 110 further includes a second PBG that is also photosensitive at light of the second wavelength, while the first PAG is not photosensitive at light of the second wavelength. At high doses of light of the second wavelength, the PBG generates basic molecules. The higher basicity of the high dose region can make the high dose region more or less soluble compared to the unreacted first region. Thus, the high dose region can be easier or more difficult to etch away to become the unreacted portion. In some embodiments, the high dose region has the same solubility as the unreacted portion.

[0061] In one or more embodiments that can be applied with the following, above, or separately described embodiments, the reaction layer 110 includes a first PAG and a first PBG. The first PAG and the first PBG are photosensitive under light of a first wavelength. The reaction layer 110 further includes a second PBG that is photosensitive under light of a second wavelength. The dose of light of the second wavelength in a portion of the reaction layer 110 is large enough such that the second PBG generates a large number of basic molecules. When this portion receives light of the first wavelength, the first PAG generates acidic molecules, but the number of acidic atoms is less than the number of basic molecules generated by the first PBG and the second PBG. Therefore, the solubility of this portion does not decrease. The reaction layer 110 has a bi-tonal behavior (e.g., the dose of light received at a known portion of the reaction layer 110 results in the generation of a soluble portion [first tone] or an insoluble portion [second tone]). In other embodiments, multiple ranges of solubility are generated, and thus the reaction layer 110 has a multi-tonal behavior.

[0062] In other embodiments, in addition to or without a PBG, the reaction layer 110 further includes a photo-crosslinkable group. In other embodiments, additional PAGs and PBGs are included in the material, allowing for more than two photosensitive wavelengths. In other embodiments, the first PBG is also photosensitive under light of the second wavelength.

[0063] In some embodiments, the solubility of the reaction layer 110 does not change until the reaction layer 110 undergoes a processing step. In these embodiments, the first wavelength and the second wavelength can be applied in any order, as long as the portion containing the first and / or second PBG receives the second wavelength before the processing step. The processing step can include a thermal baking process. The baking process provides thermal energy to the acidic molecules to enable the acidic molecules to diffuse to the polymer protecting group, and the baking provides the reaction energy to drive the deprotection reaction. In the presence of a PBG, the thermal baking provides the activation energy for the basic molecules to diffuse, enabling the basic molecules to contact and neutralize the acid.

[0064] In one or more embodiments, the material of the reaction layer 110 includes one or more novolac resins and a crosslinking compound, the crosslinking compound including diazonaphthoquinone (C 10H6N2O)[DNQ] and bis(azide). Exemplary linear phenolic resins may be or include one or more phenolic resins (PF) having a molar ratio of formaldehyde to phenol less than 1. When DNQ is photoactivated, the solubility of the phenolic resin increases. When bis(azide) is photoactivated, bis(azide) crosslinks the linear phenolic resin, and the linear phenolic resin becomes insoluble or poorly soluble. DNQ is photosensitive to light of a first wavelength from about 350 nm to about 425 nm, while bis(azide) is photosensitive to light of a second wavelength less than about 350 nm or greater than about 425 nm. The material of the reaction layer 110 becomes more soluble at the first wavelength and becomes more poorly soluble or insoluble at the second wavelength.

[0065] In other embodiments, the material includes a polymer resin, such as poly-t-BOC (poly(tert-butoxycarbonyloxystyrene)), the first region contains a PAG (such as iodonium triflate), and the second region contains a PBG (such as nitrocarbonyloxycarbonyl (NVOC) piperidine). When exposed to light of a first wavelength from about 240 nm to about 250 nm, the reaction layer 110 will have one behavior because both PAG iodonium triflate and PBG NVOC piperidine are reactive to light of the first wavelength. When the reaction layer 110 is exposed to light of a second wavelength from about 300 nm to about 375 nm, the reaction layer 110 will have a second reaction behavior because only PBG NVOC piperidine is reactive in this wavelength band. At the first wavelength of light, both PAG and PBG are photosensitive, so a bi-tone behavior can be established. At the second wavelength of light, only the PBG generator is photosensitive, and it will neutralize any acid that attempts to deprotect the poly-t-BOC photoresist.

[0066] Figure 2 is a flowchart of a method 200 according to one or more embodiments described and discussed herein, the method 200 including operations for patterning a layered structure. Although the operations of the method are described in conjunction with Figure 2 , Figures 3A to 3F , Figures 4A to 4C , Figures 5A to 5C and Figure 6 , those skilled in the art will understand that any system configured to perform the method operations in any order falls within the scope of the embodiments described herein. The method 200 may be stored or accessed by a controller 190 as a computer-readable medium containing instructions that, when executed by a processor of the controller 190, cause the lithographic apparatus 100 to perform the method 200.

[0067] Method 200 begins with operation 210, where a reaction layer 110 is disposed over a substrate to create a layered structure. In one or more embodiments, reaction layer 110 is disposed over layered structure 117. Any standard method can be used to dispose reaction layer 110. For example, reaction layer 110 can be deposited by wet coating deposition, spin coating process, and / or similar methods.

[0068] In one or more embodiments, reaction layer 110 includes a pre-mixed photoresist, and a PAG and a PBG are mixed into the photoresist. The photoresist is spin-coated onto the layered structure. The photoresist is baked at a temperature of about 50 °C to about 150 °C for a time of about 30 seconds to about 300 seconds. Baking causes the solvent to evaporate, thereby forming a polymer film photoresist.

[0069] Figure 3A The figure shows a top view of a portion of reaction layer 110 in accordance with one or more embodiments described and discussed herein. Figure 3B The figure shows a cross-sectional side view of a portion of reaction layer 110 in accordance with one or more embodiments described and discussed herein. Figures 3A to 3B The figure shows reaction layer 110 after reaction layer 110 has been disposed on substrate 115. As shown, reaction layer 110 includes one or more photosensitive chemical compounds (reaction material 300), designed to produce different reaction results under light of different wavelengths.

[0070] In one or more embodiments, reaction material 300 includes a first PAG (e.g., iodonium trifluoromethanesulfonate), a first PBG (e.g., nitrocarbonyloxycarbonyl (NVOC) piperidine), and the first PAG and the first PBG are photosensitive at a first wavelength of from 240 nm to about 250 nm. The first PBG is also photosensitive at a second wavelength of from about 300 nm to about 375 nm.

[0071] As shown, reaction material 300 includes a first region 301, two second regions 302, and two overlapping regions 305. The first region 301 is the region of reaction material 300 to be exposed to light of the first wavelength. The second regions 302 are the regions of reaction material 300 to be exposed to light of the second wavelength. The overlapping regions 305 are the regions of reaction material 300 to be exposed to light of the first and second wavelengths. Although Figures 3A to 3F The figure shows a reaction material having one first region, two second regions, and two overlapping regions, the present disclosure is not limited thereto, and may include any number of first regions, second regions, and / or overlapping regions, depending on the pattern desired by the operator. In addition, the first, second, and overlapping regions can have any desired shape. In some embodiments, the first and second regions do not overlap, and thus there are no overlapping regions. In some embodiments, a third region that receives light of a third wavelength is included.

[0072] At operation 220, the reaction layer 110 is exposed to light of multiple wavelengths. For example, the light source system 130 exposes the reaction layer 110 to light of a first wavelength and a second wavelength. The image forming apparatus 120 directs the light such that the light having the first wavelength is incident on the first region 301, the light having the second wavelength is incident on the second region 302, and the light having the first wavelength and the light having the second wavelength are incident on the overlapping region 305.

[0073] Figures 4A to 4C The figure shows light of the first wavelength incident on the reaction layer 110 according to one or more embodiments described and discussed herein. Figures 4A to 4C The figure shows the first region 301 of the reaction layer 110. Figure 4A The figure shows the first region 301 when the waveform 401 is only incident on the reaction layer 110 but before the material of the active layer begins to react to the light. The light has the waveform 401 incident on the reaction layer 110. Figure 4A The waveform 401 shown therein has a Gaussian shape, but other shaped waveforms may be considered.

[0074] As shown, the waveform 401 includes a high-dose region 411, two medium-dose regions 412, and two low-dose regions 413. The high-dose region 411 has a higher intensity than the medium-dose regions 412. The medium-dose regions 412 have a higher intensity than the low-dose regions 413. The waveform 401 is divided into the high-dose region 411, the medium-dose regions 412, and the low-dose regions 413 depending on the desired effect of the light incident on the underlying reaction layer 110. The high-dose region 411, the medium-dose regions 412, and the low-dose regions 413 are respectively incident on the high-dose region 311, the medium-dose regions 312, and the low-dose regions 313 of the first region 301.

[0075] In some embodiments, the average intensity of the medium-dose regions 412 is about 60% to about 70% of the average intensity of the high-dose region 411. In some embodiments, the average intensity of the low-dose regions 413 is about 30% to about 40% of the average intensity of the high-dose region 411. The combined width of the medium-dose regions 412 is substantially the same as the width of the high-dose region 411. The combined width of the low-dose regions 413 is substantially the same as the width of the high-dose region 411. The width of the high-dose region 411 is about 50 nm to about 1 μm.

[0076] Figure 4B The figure shows the first region 301 when the waveform 401 is incident on the reaction layer 110 and the material of the reaction layer 110 is affected by the waveform 401. At Figure 4BIn the illustrated embodiment, the high-dose region 311 and the low-dose region 313 do not significantly react with light of the first wavelength. However, the medium-dose region 312 reacts with light of the first wavelength. The material in the medium-dose region 312 is converted into a reacted material 320.

[0077] In one or more embodiments, in the high-dose region 311, the first PBG generates more basic molecules than the acidic molecules generated by the first PAG. The higher alkalinity of the high-dose region 311 gives the high-dose region the same solubility as the unreacted portion. The base covers the acid, so that no net acid can deprotect the photoresist during post-exposure baking.

[0078] In the medium-dose region 312, the first PAG generates more acidic molecules than the basic molecules generated by the first PBG. The higher acidity of the medium-dose region 312 makes this medium-dose region more soluble than the unreacted first region. When post-exposure baking drives acid diffusion and reaction kinetics to deprotect the photoresist (e.g., cleave the protecting group from the polymer), the higher acidity of the medium-dose region makes the polymer more soluble (e.g., in a TMAH aqueous developer).

[0079] In the low-dose region 313, the first PAG generates very few acidic molecules, and the first PBG generates very few basic molecules. The neutrality of the low-dose region 313 has approximately the same solubility as the unreacted first region. Therefore, the medium-dose region 312 is etched away more easily than the unreacted portion. The high-dose region 311 and the low-dose region 313 have a slower dissolution rate, so that the reaction layer 110 remains after pattern development.

[0080] Figure 3C The figure shows a top view of a portion of the reaction layer 110 according to one or more embodiments described and discussed in this case. Figure 3D The figure shows a cross-sectional side view of a portion of the reaction layer 110 according to one or more embodiments described and discussed in this case. Figure 3C With 3D The figure shows the reaction layer 110 after the reaction layer is exposed to light of the first wavelength and the second wavelength. The edge region 360 is located at the overlap region 305. Although the overlap region 305 is exposed to both the first and second wavelengths of light, the material in the overlap region does not react. However, the medium-dose region 312 has been converted into a reacted material 320.

[0081] In one or more embodiments, the first region 301 and the second region 302 at least partially overlap in the overlapping region 305. The dose of light of the second wavelength in the overlapping region 305 is large enough such that the first PBG generates a large number of basic molecules. When the overlapping region receives light of the first wavelength, the first PAG generates acidic molecules, but the number of acidic atoms is less than the number of basic molecules generated by the first and / or second PBG. Accordingly, the solubility of the overlapping region 305 is not reduced.

[0082] In operation 230, the reaction layer is exposed to a processing technique. The processing technique can include any processing technique in the art. In one or more embodiments, the reaction layer 110 is exposed to a processing technique. According to one or more embodiments described and discussed herein, the processing technique includes heating the reaction layer 110 to a temperature of from about 70 °C to about 200 °C for a time of from about 10 seconds to about 300 seconds. According to one or more embodiments described and discussed herein, the processing technique includes exposing the reaction layer 110 to a positive developer solution, such as a developer solution containing from about 2% to about 5% TMAH. According to one or more embodiments described and discussed herein, the processing technique includes exposing the reaction layer 110 to a negative developer solution, such as a developer solution containing toluene.

[0083] Figure 3E The figure shows a top view of a portion of the reaction layer 110 according to one or more embodiments described and discussed herein. Figure 3F The figure shows a cross-sectional side view of a portion of the reaction layer 110 according to one or more embodiments described and discussed herein. Figure 3E and Figure 3F The figure shows the reaction layer 110 after the reaction layer has undergone a processing technique. Figure 4C The figure marks the first region 301 after the processing technique. The medium dose region 312 has been removed to form one or more trenches 350. The trenches 350 can have a thickness of from about 1 nm to about 100 nm and a width of from about 50 nm to about 1 μm.

[0084] After method 200 is completed, a metal layer can be deposited in the trenches 350 and the reaction material 300 can be removed. Accordingly, method 200 can be used to form a circuit that includes a metal layer having a desired shape determined by method 200.

[0085] Although method 200 is described using a positive photoresist process (e.g., method 200 causes the reacted material 320 to become more soluble), the same method 200 can be applied to a negative photoresist process. In these embodiments, the medium dose region 312 becomes less soluble after exposure to light of a first wavelength, and the processing removes the remaining portion of the reaction layer 110. For example, the reaction layer 110 is exposed to toluene for a time of about 30 seconds to about 300 seconds to remove the reaction layer 110 and retain the reacted material 320. Method 200 can also be performed by a dual-tone lithography method, including both a positive photoresist method and a negative photoresist method.

[0086] Although the above method 200 includes receiving light of two different wavelengths in different regions of the reaction layer 110, other methods are conceivable. In one or more embodiments, the reaction layer 110 includes two or more different regions, each region including a different photosensitive material. The different photosensitive materials are photosensitive to light of different wavelengths. The entire reaction layer can be exposed to light of different wavelengths, so that the materials of the reaction layer react to form the desired pattern.

[0087] According to one or more embodiments described and discussed in this case, Figures 5A to 5B FIG. shows a cross-sectional side view of a portion of a workpiece 500 including a reaction layer 110 at different stages of processing, and Figure 5C FIG. shows Figure 5B a top view of a portion of the workpiece 500 described in Figure 5A As shown, the workpiece 500 includes a reaction layer 110, and the reaction layer 110 includes a reaction material disposed on a substrate 115. As described and discussed in this case, a method of patterning a layered structure on the workpiece 500 can be performed on the lithography apparatus 100.

[0088] In one or more embodiments, the reaction material includes one or more polymer photoresist materials, one or more PAGs, and one or more PBGs. The PAG is sensitive to or activated by light having a first wavelength, while the PBG is sensitive to or activated by light having a second wavelength different from the first wavelength. The first wavelength is about 240 nm to about 250 nm, and the second wavelength is about 350 nm to about 410 nm.

[0089] In one or more instances, the polymeric photoresist material is or comprises one or more polymeric resins (e.g., poly-t-BOC). In one or more instances, the PAG is or comprises one or more triflate compounds (e.g., iodonium triflate). In one or more instances, the PBG is or comprises a cyanoacrylate chromophore and a bicyclic nitrogenous base. An example of the cyanoacrylate chromophore includes the (E)-3-(2,2'-bithiophen-5-yl)-2-cyanoacrylate chromophore. Examples of the bicyclic nitrogenous base can include 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0090] As Figure 5B shown by the arrows in, workpiece 500 is exposed to a first light 512 having a first wavelength and a second light 514 having a second wavelength. When exposed to the first light 512 having the first wavelength, a first patterned region 502 ([ Figure 5A ) of the reactive material is formed or otherwise generated in the reaction layer 110. The first patterned region 502 can be or can include trenches, vias, contact vias, channels, and / or other openings that can have any shape, size, geometry, or pattern. Similarly, when exposed to the second light 514 having the second wavelength, a second patterned region 504 ([ Figure 5A ) of the reactive material is formed or otherwise generated in the reaction layer 110. The second patterned region 504 can be a negative of the first patterned region 502. In some instances, the first patterned region 502 remains unexposed to the second light 514 having the second wavelength, while the second patterned region 504 remains unexposed to the first light 512 having the first wavelength. The exposure of the first patterned region 502 and the second patterned region 504 to the first light 512 and the second light 514, respectively, occurs simultaneously with each other. For example, an acid is generated in one of the first patterned region 502 or the second patterned region 504 of the reactive material, and a base is generated in the other patterned region different from the patterned region containing the generated acid. Thus, an acid is generated in the first patterned region 502, and a base is generated in the second patterned region 504. Alternatively, a base is generated in the first patterned region 502, and an acid is generated in the second patterned region 504.

[0091] In one or more embodiments, as Figure 5B shown, the acid generated from the PAG is marked as 522 with an o within the first patterned region 502, and the base generated from the PBG is marked as 524 with an x within the second patterned region 504. In other embodiments not shown, the acid generated from the PAG can be located within the second patterned region 504, and the base generated from the PBG can be located within the first patterned region 502.

[0092] In any instance, the neutralization zone 508 is created by the reaction of an acid and a base at an interface located between the first pattern region 502 and the second pattern region 504. The neutralization zone 508 contains one or more salts produced by the acid and the base at the interface of the pattern regions 502, 504. The neutralization zone 508 (e.g., between the pattern regions 502, 504) provides the feature of sharp and clear edges, which in turn provides enhanced resolution in the lithography process described and discussed in this case as compared to traditional lithography processes. The neutralization zone 508 provides a region between the forward reaction occurring in one region (e.g., pattern region 502 or 504) and the blocking of the forward reaction occurring in an adjacent region. For example, the acid in the reaction material of the pattern region 502 or 504 removes the protecting group on the polymer photoresist material, while the base in the reaction material of the other pattern region 502 or 504 prevents the deprotection of the protecting group on the polymer photoresist material.

[0093] As described and discussed above at operation 230, the workpiece 500 including the first pattern region 502 and the second pattern region 504 can be exposed to a processing technique. In the processing technique, the first pattern region 502 and the second pattern region 504 are exposed to one or more developer solutions. In one or more instances, the first pattern region 502 of the reaction material is removed in the processing technique, and the second pattern region 504 of the reaction material is retained. The developer solution can be a positive developer solution including one or more developer bases. Alternatively, the developer solution can be a negative developer solution including one or more developer acids.

[0094] In some embodiments, a method of patterning a layered structure includes the following steps: simultaneously exposing the first pattern region 502 of the reaction material to the first light 512 of a first wavelength and exposing the second pattern region 504 of the reaction material to the second light 514 of a second wavelength; generating an acid in the first pattern region 502 of the reaction material while generating a base in the second pattern region 504 of the reaction material; and generating a neutralization zone 508 from the generated acid and the generated base at the interface between the first pattern region 502 and the second pattern region 504. The method further includes the step of exposing the first pattern region 502 and the second pattern region 504 of the reaction material to a developer solution (e.g., a positive developer solution) in a processing technique such that the first pattern region 502 of the reaction material can be removed in the processing technique and the second pattern region 504 of the reaction material can be retained. In other instances, the developer solution is a negative developer solution such that the first pattern region 502 of the reaction material can be retained in the processing technique and the second pattern region 504 of the reaction material can be removed.

[0095] In one or more embodiments, the reactive material in the reactive layer comprises one or more polymer photoresist materials, one, two, or more crosslinking inhibitors, and optionally one or more quenchers. In some instances, the reactive material comprises one or more polymer photoresist materials, a first crosslinking inhibitor, and a second crosslinking inhibitor. In other instances, the reactive material comprises one or more polymer photoresist materials, a crosslinking inhibitor, and one or more quenchers.

[0096] In one or more embodiments, a method of patterning a layered structure includes the steps of disposing a reactive material over the layered structure and / or substrate. The reactive material comprises a polymer photoresist material, a first crosslinking inhibitor, and a second crosslinking inhibitor. The first crosslinking inhibitor is sensitive to a first wavelength, and the second crosslinking inhibitor is sensitive to a second wavelength different from the first wavelength. The method further includes the steps of simultaneously exposing a first patterned region of the reactive material to first light of the first wavelength and exposing a second patterned region of the reactive material to second light of the second wavelength to thereby produce a first activated crosslinking inhibitor in the first patterned region of the reactive material while producing a second activated crosslinking inhibitor in the second patterned region of the reactive material; and creating a neutralization zone from the first activated crosslinking inhibitor and the second activated crosslinking inhibitor at an interface between the first patterned region and the second patterned region.

[0097] Figure 6 FIG. shows a top view of a portion of a workpiece 600 including a reactive layer 110 at one processing stage in accordance with one or more embodiments described and discussed herein. The workpiece 600 is similar to the workpiece 500, but the workpiece 600 also has a third patterned region 506 of reactive material that is exposed to both the first light and the second light, as Figure 6 shown. The third patterned region 506 can be a cut area or region on the workpiece 600. Thus, during the processing operation 230, after the reactive material in the first patterned region 502 is removed, the reactive material in the third patterned region 506 can remain on the workpiece 600 together with the reactive material in the second patterned region 504.

[0098] In one or more embodiments, workpiece 600 includes reaction layer 110, which comprises a reactive material disposed on a layered structure or substrate. The reactive material comprises one or more polymer photoresist materials, one or more PAGs, and one or more PBGs. The PAG is sensitive at a first wavelength, while the PBG is sensitive at a second wavelength different from the first wavelength. The method includes the steps of simultaneously exposing a first patterned region 502 of the reactive material to first light at the first wavelength, exposing a second patterned region 504 of the reactive material to second light at the second wavelength, and exposing a third patterned region 506 of the reactive material to first light at the first wavelength and second light at the second wavelength. In some instances, the third patterned region 506 is a portion of the first patterned region 502, as Figure 6 shown. In other instances, the third patterned region 506 is a portion of the second patterned region 504 (not shown). In other instances, the third patterned region 506 is a portion of both the first patterned region 502 and the second patterned region 504 (not shown).

[0099] The method further includes the steps of generating acid from the PAG in the first patterned region 502 of the reactive material, while generating base from the PBG in the second patterned region 504 and the third patterned region 506 of the reactive material. A neutralization zone 508 is disposed at the interface between the first patterned region 502 and the second patterned region 504 and between the first patterned region 502 and the third patterned region 506. In one or more instances, the first patterned region 502 remains unexposed to second light having the second wavelength, while the second patterned region 504 remains unexposed to first light having the first wavelength, and the third patterned region 506 is exposed to first light having the first wavelength and second light having the second wavelength.

[0100] As described above, a lithography apparatus, a patterning system, and a method for patterning a layered structure are provided. The patterning system includes an image forming device and a reaction layer. The patterning system allows creation of a lithographic pattern. The lithography apparatus includes the patterning system and an optical system. The lithography apparatus uses light of multiple wavelengths together with the image forming device to form multiple different color images and / or patterns on the reaction layer. The patterning method includes exposing the reaction layer to light of multiple different wavelengths. The reaction layer reacts differently to light of different wavelengths, enabling formation of multiple color images and / or one or more composite images in a single lithography step.

[0101] The methods and apparatuses disclosed herein require one lithography step that generates a net composite image that would otherwise require multiple lithography steps and multiple masks. Additionally, use of the image forming device reduces the need for multiple mask alignments, thereby reducing lithography time.

[0102] Although the foregoing is directed to embodiments of the present case, other and further embodiments may be devised without departing from the basic scope of the present case, and the scope of the present case is determined by the scope of the claims. All documents described in the present case are incorporated herein by reference, including any priority documents and / or test procedures that are not inconsistent with the present case. From the foregoing general description and specific embodiments, it is apparent that, although the forms of the present case have been shown and described, various modifications may be made without departing from the spirit and scope of the present case. Accordingly, it is not intended to limit the present case thereby. Similarly, for legal purposes, the term "comprising" should be considered synonymous with the term "including". Likewise, whenever a transitional phrase "comprising" is prefixed to a composition, an element, or a group of elements, it should be understood as having the transitional phrases "consisting essentially of", "consisting of", "selected from the group consisting of", or "is" before the recitation of the composition, element, or elements, and vice versa.

[0103] As used in the present case, the term "about" means a difference of + / - 10% from the nominal value. It should be understood that such variations may be included in any value provided in the present case.

[0104] Certain embodiments and features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be understood that, unless otherwise indicated, ranges encompassing any combination of any two values are covered, e.g., any combination of any lower value with any higher value, any combination of any two lower values, and / or any combination of any two higher values. Certain lower limits, upper limits, and ranges are shown in one or more of the following claims.

Claims

1. A lithographic apparatus operable to pattern a reactive layer of a material, the reactive layer of the material having a first photoacid generator and a first photobase generator at a first region and a second region, the lithographic apparatus comprising: a substrate support configured to support a layered structure; a light source system capable of emitting light having two or more wavelengths, the wavelengths including a first wavelength and a second wavelength; and an imaging device, the imaging device comprising: a first device region capable of allowing transmission of the light of the first wavelength and generating a first light image at the first wavelength to be projected onto the first region of the reactive layer of the layered structure, the first region having at least a first portion, the first wavelength activating the first photoacid generator and the first photobase generator; a second device region capable of allowing transmission of the light of the second wavelength and generating a second light image at the second wavelength to be projected onto the second region of the reactive layer of the layered structure, the second region having at least a second portion, wherein the first portion and the second portion are disposed over different regions of the layered structure.

2. The lithographic apparatus according to claim 1, wherein the light source system includes a light source configured to emit light having the two or more wavelengths, the imaging device includes a digital micromirror device, and the digital micromirror device is configured to project a light image having the two or more wavelengths.

3. The lithographic apparatus according to claim 1, wherein the imaging device includes a first digital micromirror device and a second digital micromirror device, the first digital micromirror device is configured to project the light of the first wavelength among the two or more wavelengths, and the second digital micromirror device is configured to project the light of the second wavelength among the two or more wavelengths.

4. The lithographic apparatus according to claim 1, wherein the imaging device includes a first photomask and a second photomask, the first photomask is configured to project the light of the first wavelength among the two or more wavelengths, and the second photomask is configured to project the light of the second wavelength among the two or more wavelengths.

5. The lithographic apparatus according to claim 1, wherein the light source system includes a light source configured to emit light having the two or more wavelengths, the imaging device includes a photomask, and the photomask is configured to project the light image having the two or more wavelengths.

6. A patterning system operable to pattern a reactive layer of a material, the reactive layer of the material having a first photoacid generator and a first photobase generator at a first region and a second region, the patterning system comprising: an imaging device, the imaging device comprising: a first device region capable of generating a first light image at a first wavelength to be projected onto the first region of the reactive layer; and A second device region capable of generating a second light image at a second wavelength to be projected onto the second region of the reaction layer; and The reaction layer comprising a reaction material, the reaction material including: The first region having at least a first portion, the first wavelength activating the first photoacid generator and the first photobase generator; and The second region having at least a second portion; wherein The image forming device is configured to allow the first light image to be transmitted onto the first region, and The image forming device is configured to allow the second light image to be transmitted onto the second region, wherein the first portion and the second portion are disposed over different regions of the reaction layer.

7. The patterning system of claim 6, wherein the first region includes: A low dose region; A medium dose region; And A high dose region; Wherein The image forming device is configured to allow light of the first wavelength to have a higher dose in the high dose region than in the medium dose region, and The image forming device is configured to allow light of the first wavelength to have a higher dose in the medium dose region than in the low dose region.

8. The patterning system of claim 6, wherein the image forming device includes one or more digital micromirror devices.

9. The patterning system of claim 6, wherein the image forming device includes one or more photomasks.

10. A method of patterning a layered structure, comprising the steps of: A reaction layer is provided on the layered structure; And Exposing the reaction layer to light of multiple wavelengths by an image forming device, the image forming device including: A first device region capable of generating a first light image at a first wavelength to be projected onto a first region of a reaction layer, the first region having at least a first portion; and A second device region capable of generating a second light image at a second wavelength to be projected onto a second region of the reaction layer, the second region having at least a second portion; The reaction layer includes a reaction material, the reaction material including the first region and the second region, the step of exposing the reaction layer including the steps of: Exposing the first region to light of the first wavelength using the image forming device; and Exposing the second region to light of the second wavelength using the image forming device, wherein the first portion and the second portion are disposed over different regions of the reaction layer, Wherein the reaction material includes a first photoacid generator and a first photobase generator, wherein each of the first photoacid generator and the first photobase generator is sensitive at the first wavelength.

11. The method of claim 10, wherein the image forming device includes one or more digital micromirror devices.

12. The method of claim 10, wherein the reaction material further includes a second photobase generator sensitive at the second wavelength.

13. The method of claim 10, wherein the step of exposing the first region and the step of exposing the second region occur simultaneously.

14. The method according to claim 10, wherein the step of exposing the first region and the step of exposing the second region occur sequentially, and the step of exposing the first region and the step of exposing the second region are repeated one or more times.

15. The method according to claim 10, wherein the first region and the second region at least partially overlap.

16. The method according to claim 10, wherein the first region comprises: a low-dose region; a medium-dose region; and a high-dose region; wherein the image forming device is configured to allow light of the first wavelength to have a higher dose in the high-dose region than in the medium-dose region, and the image forming device is configured to allow light of the first wavelength to have a higher dose in the medium-dose region than in the low-dose region.

Images