Extreme ultraviolet light mask and manufacturing method thereof

Abstract

An extreme ultraviolet light mask includes an absorbing layer having a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.065 to 0.085, and a thickness in the range of 33.5 nm to 43.5 nm. Another extreme ultraviolet light mask includes an absorbing layer having a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.085 to 0.105, and a thickness in the range of 25.5 nm to 35.5 nm. Another extreme ultraviolet light mask includes an absorbing layer having a refractive index in the range of 0.895 to 0.950, an extinction coefficient in the range of 0.0600 to 0.0610, and a thickness in the range of 30 nm to 39 nm or 50 nm to 55 nm.

Description

[0001] This application is a divisional application of a patent application with an application date of July 31, 2019, application number 201910700227.X, and invention name “Extreme ultraviolet light mask and its manufacturing method”. Technical Field

[0002] The present disclosure relates to an extreme ultraviolet light mask and a manufacturing method thereof. Background Art

[0003] As consumer demand continues, consumer electronic components are becoming thinner and smaller, and the size of the components of these components is bound to decrease. Semiconductor devices are the main components of mobile phones, computer tablets and other devices, and the components in them are also under pressure to reduce their size. With the advancement of semiconductor manufacturing technology, such as lithography, the reduction of component size has been achieved.

[0004] For example, the wavelength of radiation used for lithography has decreased, from ultraviolet to deep ultraviolet (DUV) and, more recently, extreme ultraviolet (EUV). Further reductions in feature size require further increases in lithography resolution, which can be achieved by extreme ultraviolet lithography (EUVL). EUVL uses radiation with wavelengths of approximately 1-100 nm.

[0005] As the semiconductor industry moves to nanotechnology process nodes in pursuit of higher device density, higher performance, and lower cost, there are challenges in reducing semiconductor feature sizes. Summary of the invention

[0006] An extreme ultraviolet light mask comprises a plurality of alternately stacked first reflection layers and second reflection layers disposed on a substrate; a ruthenium capping layer disposed on the alternately stacked first reflection layers and second reflection layers; an absorption layer with a pattern disposed on the ruthenium capping layer; and a black border. The absorption layer has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption layer is 2.00×10 -5 , wherein the material of the absorption layer is an alloy material including Te. A black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate.

[0007] An extreme ultraviolet light mask comprises a plurality of alternately stacked first reflection layers and second reflection layers disposed on a substrate; a ruthenium cap layer disposed on the alternately stacked first reflection layers and second reflection layers; an absorption layer having a pattern disposed on the ruthenium cap layer; and a black border. The absorption layer has a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.085 to 0.105, and a thickness in the range of 28.5 nm to 32.5 nm, wherein the material of the absorption layer is an alloy material containing Te. The black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate.

[0008] A method for manufacturing an extreme ultraviolet light mask comprises forming a plurality of alternately stacked first reflection layers and second reflection layers on a substrate; forming a ruthenium cap layer on the plurality of alternately stacked first reflection layers and second reflection layers; forming an absorption film on the ruthenium cap layer; forming a pattern in the absorption film; forming a black border surrounding the pattern and arranged in the absorption film by lithography and etching operations, wherein the pattern of the black border extends from the surface of the absorption film to the substrate. The absorption film has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption film is 2.00×10 -5 , wherein the material of the absorption film is an alloy material containing Te. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The disclosure may be better understood from the following examples and accompanying drawings. It should be noted that, in accordance with standard practice in the industry, many components are not drawn to scale. In fact, the dimensions of many components may be arbitrarily enlarged or reduced for clarity of discussion.

[0010] Figure 1 is a diagram illustrating an extreme ultraviolet lithography tool according to one embodiment of the present disclosure;

[0011] Figure 2 is a simplified schematic diagram of details of an EUV lithography tool according to one embodiment of the present disclosure;

[0012] Figure 3 is a cross-sectional view of a reflective light mask according to an embodiment of the present disclosure;

[0013] Figure 4 Graphs reflectivity and normalized horizontal pattern optimal focus offset according to an embodiment of the present disclosure;

[0014] Figure 5 Graphs reflectivity and normalized horizontal pattern optimal focus offset according to an embodiment of the present disclosure;

[0015] Figure 6The simulation of the thickness of the absorption layer and the reflectivity of the absorption layer under different extinction coefficients according to the embodiment of the present disclosure is shown;

[0016] Figure 7 depicts a simulation of pattern spacing and optimal focus according to various examples of the present disclosure;

[0017] Figure 8 A simulation of pattern pitch and individual focal depth according to various examples of the present disclosure is shown;

[0018] Fig. 9 depicts a simulation of pattern spacing and image logarithmic slope according to various examples of the present disclosure;

[0019] Fig.10 depicts simulations of pattern pitch and horizontal-vertical deviation according to various examples of the present disclosure;

[0020] Fig.11 A flow chart of a method for manufacturing an EUV mask according to an embodiment of the present disclosure is shown;

[0021] Fig.12 A flow chart of a method for optimizing an absorption layer of an EUV photomask according to one embodiment of the present disclosure is shown;

[0022] Fig.13 A flow chart of a method for manufacturing a semiconductor device according to an embodiment of the present disclosure is shown;

[0023] Fig.14A , 14B 14C shows a simulation result of optimizing the reflectivity of an EUV photomask according to one embodiment of the present disclosure;

[0024] Fig.15A and 15B illustrates a simulation of optimizing the reflectivity of an EUV photomask according to one embodiment of the present disclosure;

[0025] Fig.16A , 16B , 16C, 16D, 16E, 16F, 16G and 16H illustrate simulation optimization results of an EUV mask for a pattern in a vertical direction according to an embodiment of the present disclosure;

[0026] Fig.17A , 17B , 17C, 17D, 17E, 17F, 17G and 17H illustrate simulation optimization results of an EUV mask for vertical patterns according to an embodiment of the present disclosure.

[0027]

Explanation of symbols

[0028] 10 substrates

[0029] 30 substrates

[0030] 35+ pairs of reflective layers

[0031] 37 first reflection layer

[0032] 39 Second reflection layer

[0033] 40 Covering layer

[0034] 45 absorption layer (film)

[0035] 55 patterns

[0036] 60 Conductive Layer

[0037] 65 Black Border

[0038] 100 Extreme Ultraviolet Radiation Source

[0039] 105 Chamber

[0040] 110 Collector

[0041] 115 Target Droplet Generator

[0042] 120 Nozzle

[0043] 125 droplet catcher

[0044] 130 Gas Supply

[0045] 140 Exit

[0046] 200 Exposure device

[0047] 210 substrate

[0048] 300 Excitation laser source

[0049] 310 Laser Generator

[0050] 320 Laser Guidance Optics

[0051] 330 Focusing Equipment

[0052] 205a, 205b, 205c, 205d, 205e optical elements

[0053] 500 600 Method

[0054] BF bottom layer

[0055] DP target droplet

[0056] DP1 DP2 Damper

[0057] LPP Laser Produced Plasma

[0058] LR1 Laser

[0059] LR2 excitation laser

[0060] MF Main Floor

[0061] ML Multi-Reflection Layer

[0062] PP1 PP2 Base plate

[0063] S410 S420 S430 S440 S450 S510 S520 S530 S540 S550 S610 S620 Operation

[0064] ZE Radiator DETAILED DESCRIPTION

[0065] It should be understood that many different implementation methods or examples are disclosed below to implement the different features of the subject matter provided. The following describes specific embodiments of the elements and their arrangements to illustrate the present disclosure. Of course, these embodiments are only for illustration and should not be used to limit the scope of the present disclosure. For example, the size of the element is not limited to the disclosed range or value, but may depend on the operating conditions and / or required characteristics of the element. In addition, it is mentioned in the specification that the first characteristic element is formed on the second characteristic element, which includes an embodiment in which the first characteristic element and the second characteristic element are in direct contact, and also includes an embodiment in which there are other features between the first characteristic element and the second characteristic element, that is, the first characteristic element and the second characteristic element are not in direct contact. For simplicity and clarity, various characteristic elements can be arbitrarily drawn in different proportions.

[0066] In addition, spatially related terms may be used, such as "below", "below", "lower", "above", "higher" and similar terms. These spatially related terms are used to facilitate the description of the relationship between one (some) element or feature and another (some) element or feature in the figure. These spatially related terms include different orientations of the device in use or operation, as well as the orientations described in the drawings. When the device is turned to a different orientation (rotated 90 degrees or other orientations), the spatially related adjectives used therein will also be interpreted according to the orientation after the rotation. In addition, the term "consisting of" can mean "including" or "consisting of".

[0067] The present disclosure relates to extreme ultraviolet (EUV) lithography masks and methods thereof. In an EUV lithography tool, a laser produced plasma (LPP) generates EUV radiation for imaging onto a substrate 210 coated with a photoresist. In an EUVL tool, the laser produced plasma LPP heats a metal (e.g., tin, lithium, etc.) target droplets located in a laser excited plasma chamber to ionize the droplets into a plasma, and the plasma emits EUV radiation. In order to reproducibly generate EUV light, the target droplets must arrive at the focus of the excitation laser (also referred to herein as the "excitation zone") at the same time as the excitation pulse from the excitation laser. Therefore, stable generation of target droplets and arrival at the excitation zone at a consistent (or predictable) rate contributes to the efficiency and stability of the EUV radiation source of the laser excited plasma.

[0068] Figure 1 is a schematic diagram of an EUV lithography tool according to some embodiments of the present disclosure, wherein the EUV lithography tool has an EUV radiation source based on laser-generated plasma. The EUV lithography system includes an EUV radiation source 100 for generating EUV radiation, an exposure device 200, such as a scanner, and an excitation laser source 300. Figure 1 As shown, in some embodiments, the extreme ultraviolet radiation source 100 and the exposure device 200 are installed on the main floor MF of the clean room, and the excitation laser source 300 is installed in the bottom floor BF located below the main floor MF. Each of the extreme ultraviolet radiation source 100 and the exposure device 200 is placed on pedestal plates PP1 and PP2 through dampers DP1 and DP2, respectively. The extreme ultraviolet radiation source 100 and the exposure device 200 are coupled to each other through a coupling mechanism, and the coupling mechanism may include a focusing unit.

[0069] The EUV lithography tool is designed to expose the impedance layer to extreme ultraviolet light (EUV light, also interchangeably referred to herein as EUV radiation). The above-mentioned impedance layer is a material sensitive to EUV light. The EUV lithography system uses an EUV radiation source 100 to generate EUV light, such as EUV light with a wavelength range between about 1 nm and about 100 nm. In a specific example, the EUV radiation source 100 generates EUV light with a central wavelength of about 13.5 nm. In the present embodiment, the EUV radiation source 100 uses a laser produced plasma (LPP) mechanism to generate EUV radiation.

[0070] The exposure device 200 includes various reflective optical elements (e.g., convex mirrors / concave mirrors / plane mirrors), a mask holding mechanism including a mask stage, and a wafer holding mechanism. The EUV radiation generated by the EUV radiation source 100 is guided by the reflective optical elements to the mask fixed on the mask stage. In some embodiments, the mask stage includes an electrostatic chuck (e-chuck) to fix the mask.

[0071] Figure 2 is a simplified schematic diagram of details of an EUV lithography tool according to some embodiments of the present disclosure, which shows exposing a photoresist-coated substrate 210 with a patterned beam of EUV light. The exposure device 200 is an integrated circuit lithography tool, such as a stepper, a scanner, a step and scan system, a direct write system, a device using a contact and / or proximity mask, etc., and is provided with one or more optical elements 205a, 205b, such as a patterned optical element 205c (such as a reticle) for irradiating with an EUV beam and generating a patterned beam, and one or more reduced projection optical elements 205d, 205e for projecting the patterned beam onto the substrate 210. A mechanical component (not shown) may be provided to generate a controlled relative motion between the substrate 210 and the patterned optical element 205c. As Figure 2 As further shown in , the EUV tool includes an EUV radiation source 100 including an EUV radiator ZE that emits EUV light in a chamber 105 , which is reflected by a collector 110 along a path into an exposure device 200 to illuminate a substrate 210 .

[0072] The term "optical element" as used herein is intended to be broadly interpreted to include, but is not limited to, one or more elements used to reflect and / or transmit and / or manipulate incident light, and includes, but is not limited to, one or more lenses, windows, filters, wedges, prisms, grisms, gratings, transmission fibers, etalons, diffusers, homogenizers, detectors and other instrument components, apertures, axicons, and mirrors (including multi-layer mirrors, near-normal incidence mirrors, grazing incidence mirrors, specular reflectors, diffuse reflectors, and combinations thereof). In addition, unless otherwise specified, the term "optical element" as used herein is not limited to elements that operate solely or advantageously within one or more specific wavelength ranges (e.g., at the output light wavelength of extreme ultraviolet light, the illuminating laser wavelength, a wavelength suitable for metrology, or any other specific wavelength).

[0073] Since gas molecules absorb EUV light, the EUV lithography system is kept in a vacuum or low-pressure environment to avoid loss of EUV light intensity.

[0074] In the present disclosure, the terms mask, photomask, and reticle are used interchangeably. In the present embodiment, the patterned optical element 205c is a reflective photomask. In some embodiments, the reflective photomask 205c includes a substrate having a suitable material, such as a low thermal expansion material or fused silica. Figure 3As shown, in various examples, the material includes SiO2 doped with TiO2, or other suitable materials with low thermal expansion. The reflective mask 205c includes multiple pairs of reflective layers (ML) deposited on a substrate. The multiple pairs of reflective layers include multiple pairs of film pairs, such as molybdenum-silicon (Mo / Si) film pairs (for example, in each pair of film pairs, a molybdenum layer 39 is located above or below a silicon layer 37). Alternatively, the multiple pairs of reflective layers 35 may include molybdenum-beryllium (Mo / Be) film pairs, or other suitable materials configured to highly reflect extreme ultraviolet light. The mask 205C may also include a cap layer 40, such as composed of ruthenium (Ru), disposed above the multiple pairs of reflective layers for protection. The mask further includes an absorption film (or absorption layer) 45 deposited above the multiple pairs of reflective layers 35. The absorption film 45 is patterned to define a layer of an integrated circuit (IC). Since the absorber layer 45 has a finite reflectivity, even if the reflectivity of the absorber layer is much less than the reflectivity of the multiple pairs of reflective layers 35, the reflectivity of the absorber layer 45 coupled with the height of the absorber layer 45 above the multiple pairs of reflective layers 35 may produce an undesirable phase shift of the EUV radiation reflected by the mask 205c. This undesirable EUV radiation phase shift is also called a mask 3D effect.

[0075] In some embodiments, the reflective mask 205c includes a conductive back coating 60. In some embodiments, the reflective mask 205c includes a border 65 etched down to the substrate 30 and surrounding the pattern 55, also referred to as a black border 65, to define the circuit area to be imaged and the peripheral area not to be imaged. In some embodiments, the black border reduces light leakage.

[0076] In various embodiments of the present disclosure, the photoresist-coated substrate 210 is a semiconductor wafer, such as a silicon wafer or other types of wafers to be patterned.

[0077] In some embodiments, the EUV lithography tool further includes other modules or is integrated (or coupled) with other modules.

[0078] like Figure 1 As shown, the EUV radiation source 100 includes a target droplet generator 115 and a laser generated plasma collector 110 surrounded by a chamber 105. In some embodiments, the target droplet generator 115 includes a reservoir for holding source material and a nozzle 120, through which target droplets DP of the source material are supplied to the chamber 105.

[0079] In some embodiments, the target droplets DP are droplets of tin (Sn), lithium (Li) or tin-lithium alloy. In some embodiments, each target droplet DP has a diameter of about 10 micrometers (μm) to about 100 μm. For example, in some embodiments, the target droplets DP are tin droplets and have a diameter of about 10 μm to about 100 μm. In other embodiments, the target droplets DP are tin droplets with a diameter of about 25 μm to about 50 μm. In some embodiments, the target droplets DP are supplied through the nozzle 120 at a rate of about 50 drops per second (i.e., a spraying frequency of about 50 Hz) to about 50,000 drops per second (i.e., a spraying frequency of about 50 kHz). In some embodiments, the target droplets DP are supplied at a spraying frequency of about 100 Hz to about 25 kHz. In other embodiments, the target droplets DP are supplied at a spraying frequency of about 500 Hz to about 10 kHz. The target droplet DP is ejected into the excitation zone ZE through the nozzle 120, and in some embodiments, its velocity ranges from about 10 meters / second (m / s) to about 100 m / s. In some embodiments, the target droplet DP has a velocity of about 10 m / s to about 75 m / s. In other embodiments, the velocity of the target droplet is about 25 m / s to about 50 m / s.

[0080] Reference again Figure 1 , the excitation laser LR2 generated by the excitation laser source 300 is a pulsed laser. The excitation laser source 300 generates the excitation laser LR2. The excitation laser source 300 may include a laser generator 310, a laser guiding optical element 320, and a focusing device 330. In some embodiments, the laser source 300 includes a carbon dioxide (CO2) or a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser source and has a wavelength in the infrared region of the electromagnetic spectrum. For example, in some embodiments, the laser source 300 has a wavelength of 9.4 μm or 10.6 μm. The laser LR1 generated by the laser generator 310 is guided by the laser guiding optical element 320 and focused into the excitation laser LR2 by the focusing device 330, and then introduced into the extreme ultraviolet radiation source 100.

[0081] In some embodiments, the excitation laser LR2 includes a preheating laser and a main laser. In such embodiments, a preheating laser pulse (interchangeably referred to herein as a "pre-pulse") is used to heat (or preheat) a given target droplet to produce a low-density target plume with multiple smaller droplets, which is subsequently heated (or reheated) by a pulse from the main laser, resulting in an increase in the emission of extreme ultraviolet light.

[0082] In various embodiments, the preheating laser pulse has a spot size of about 100 μm or less, and the main laser pulse has a spot size in the range of about 150 μm to about 300 μm. In some embodiments, the preheating laser and the main laser pulse have a pulse duration in the range of about 10 ns to about 50 ns, and a pulse frequency in the range of about 1 kHz to about 100 kHz. In various embodiments, the average power of the preheating laser and the main laser is in the range of about 1 kilowatt (kW) to about 50 kW. In some embodiments, the pulse frequency of the excitation laser LR2 matches the ejection frequency of the target droplet DP.

[0083] The excitation laser LR2 is guided through a window (or lens) into the excitation zone ZE. The window is made of a suitable material that is substantially transparent to the laser beam. The generation of the pulsed laser is synchronized with the ejection of the target droplet DP through the nozzle 120. When the target droplet moves through the excitation zone, the pre-pulse heats the target droplet and converts the target droplet into a low-density target plume. The delay between the pre-pulse and the main pulse is controlled to allow the target plume to form and expand to an optimal size and geometry. In various embodiments, the pre-pulse and the main pulse have the same pulse duration and peak power. When the main pulse heats the target plume, a high-temperature plasma is generated. The plasma emits extreme ultraviolet radiation, which is collected by the collector 110. The collector 110 further reflects and focuses the extreme ultraviolet radiation and provides it to the lithography exposure process performed by the exposure device 200. The droplet catcher 125 is used to capture excess target droplets. For example, the laser pulse may intentionally miss some target droplets.

[0084] Reference again Figure 1 , the collector 110 is designed with appropriate coating materials and shapes to act as a mirror for collecting, reflecting and focusing EUV light. In some embodiments, the collector 110 is designed to have an elliptical geometry. In some embodiments, the coating material of the collector 100 is a reflective multilayer similar to an EUV light mask. In some examples, the coating material of the collector 110 includes multiple pairs of reflective layers (e.g., multiple molybdenum / silicon film pairs) and may further include a cap layer (e.g., Ru) coated on the ML to substantially reflect the EUV light. In some embodiments, the collector 110 may further include a grating structure designed to effectively scatter a laser beam directed onto the collector 110. For example, a silicon nitride layer is coated on the collector 110, and the silicon nitride layer is patterned to obtain a grating pattern.

[0085] In such an EUV radiation source, the plasma created by the application of the laser generates physical debris such as ions, gases and atoms of droplets, as well as the desired EUV radiation. It is necessary to prevent material from accumulating on the collector 110 and to prevent the physical debris from leaving the chamber 105 and entering the exposure device 200.

[0086] like Figure 1 As shown, in the present embodiment, the buffer gas is supplied from the first buffer gas supplier 130 and passes through the holes in the collector 110, and the pulsed laser is transmitted to the tin droplets through the holes. In some embodiments, the buffer gas is H2, He, Ar, N2 or other inert gases. In certain embodiments, H2 is used as H radicals generated by the dissociation of the buffer gas and can be used for cleaning purposes. The buffer gas can also be provided toward the collector 110 and / or around the boundary of the collector 110 by one or more second buffer gas suppliers 130. In addition, the chamber 105 includes one or more gas outlets 140 so that the buffer gas can be discharged outside the chamber 105.

[0087] Hydrogen has a low absorption of EUV radiation. The hydrogen reaching the coating surface of the collector 110 reacts chemically with the metal of the droplet to form a hydride, such as a metal hydride. When tin (Sn) is used as the droplet, stannane (SnH4) is formed, which is a gaseous byproduct of the EUV generation process, and the gaseous SnH4 can then be pumped out through the outlet 140.

[0088] Figure 4 A simulation of the absorber reflectivity and the normalized level optimal focus shift according to an embodiment of the present disclosure is shown. Figure 5 FIG. 4 is a diagram showing a simulation of the absorber reflectivity and the normalized vertical best focus offset according to an embodiment of the present disclosure. Figure 4 and Figure 5 The R2 in the equation is the coefficient of determination, which is used to measure the proportion of the variation of the dependent variable that can be explained by the independent variable, so as to judge the explanatory power of the model. Figure 4 The R2 is 0.80 ± 0.05 and Figure 5 The R2 in is 0.95±0.05. The normalized best focus shift is defined as the best focus shift divided by the absorber layer thickness. The through-pitch normalized best focus shift is strongly correlated with the absorber layer reflectivity, i.e., a smaller reflectivity results in a smaller normalized best focus shift. It is desired that the absorber layer thickness is as small as possible while keeping the reflectivity as low as possible to reduce the 3D effect of the mask. However, if the absorber layer is too thin, the incident radiation will not be fully absorbed by the absorber layer. The difference in reflectivity in the horizontal and vertical directions comes from the fact that the EUV lithography system is a reflective rather than a non-telecentric system. The EUV exposure radiation comes from an incident angle of 6 degrees, rather than a normal incident angle. The oblique incident angle of the EUV radiation destroys the symmetry between the horizontal and vertical patterns, resulting in differences in the exposure parameters of the horizontal and vertical patterns.

[0089] The lowest reflectivity of the absorbing layer occurs at the local minimum of the Fabry-Perot interference in the absorbing layer. Figure 6 is a graph of simulated absorption layer thickness and absorption layer reflectivity at different extinction coefficients (k) according to an embodiment of the present disclosure. Figure 6 As shown, the reflectivity minimum values ​​have been found to be at absorber layer thicknesses of about 27 nm, about 30.5 nm, about 38.5 nm, about 48 nm, about 56 nm, and about 63 nm. However, Figure 6 The simulations shown were performed without a capping layer. Taking into account a 3.5 nm ruthenium capping layer, the reflectivity minima of the absorber layer are at absorber layer thicknesses of about 23.5 nm, about 30.5 nm, about 38.5 nm, about 52.5 nm, and about 59.5 nm, respectively. The extinction coefficient is a measure of how easily a material is penetrated by a light beam in a given volume. Figure 6 As shown, the higher the extinction coefficient, the lower the reflectivity. Therefore, it is desirable to use an absorbing layer material with a high extinction coefficient.

[0090] The reflectivity of the absorption layer having a thickness of about 30.5 nm to about 38.5 nm is lower than the reflectivity of the absorption layer having a thickness of about 23.5 nm. For example, the reflectivity at 23.5 nm is about 0.06, while the reflectivity at 30.5 nm is about 0.04, and the reflectivity at 38.5 nm is about 0.02. At greater thicknesses, the absorption layer may have issues with the mask 3D effect. In some embodiments, thinner absorption layers are preferred to reduce issues with the mask 3D effect. In some embodiments, the thickness of the absorption layer 45 ranges from about 19.5 nm to about 43.5 nm. In some embodiments, the thickness of the absorption layer 45 ranges from about 21.5 to about 25.5 nm, from about 28.5 nm to about 32.5 nm, or from about 36.5 nm to about 40.5 nm. In some embodiments, absorption layer thicknesses outside of these ranges reduce the resolution of the photoresist pattern.

[0091] According to embodiments of the present disclosure, the refractive index (index of refraction), the extinction coefficient (extinction coefficient), and the thickness of the absorption layer 45 are optimized to provide improvements in yellow photolithography performance. In some embodiments, the absorption layer 45 has a refractive index ranging from about 0.87 to about 1.02. In some embodiments, the absorption layer 45 has a refractive index ranging from about 0.90 to about 1.00. In some embodiments, the absorption layer 45 has a refractive index ranging from about 0.95. In some embodiments, the absorption layer 45 has an extinction coefficient ranging from about 0.065 to about 0.085. In some embodiments, the extinction coefficient of the absorption layer 45 ranges from about 0.070 to about 0.080. In some embodiments, the extinction coefficient and refractive index outside the above ranges reduce the resolution of the photoresist pattern. In some embodiments, the extinction coefficient of the absorption layer 45 ranges from about 0.075. In some embodiments, the thickness of the absorption layer 45 ranges from about 33.5 nm to about 43.5 nm. In some embodiments, the thickness of the absorption layer 45 ranges from about 35.5 nm to about 39.5 nm. In some embodiments, the thickness of absorber layer 45 is about 38.5 nm.

[0092] In other embodiments, the thickness of the absorption layer 45 ranges from about 25.5 nm to about 35.5 nm. In some embodiments, the thickness of the absorption layer 45 ranges from about 27.5 nm to about 31.5 nm. In some embodiments, the absorption layer 45 has a thickness of about 30.5 nm. In other embodiments, the absorption layer 45 has a refractive index ranging from about 0.87 to about 1.02. In some embodiments, the absorption layer 45 has a refractive index ranging from about 0.90 to about 1.00. In some embodiments, the absorption layer 45 has a refractive index of about 0.95. In some embodiments, the absorption layer 45 has an extinction coefficient ranging from about 0.085 to about 0.105. In some embodiments, the absorption layer 45 has an extinction coefficient of about 0.090 to about 0.100. In some embodiments, the extinction coefficient of the absorption layer 45 is about 0.095. In some embodiments, the extinction coefficient and refractive index outside the above ranges reduce the resolution of the photoresist pattern.

[0093] In some embodiments, the absorption layer 45 is made of a material selected from Sn, Ni, Te, Co, In, Sb, and alloys thereof. In some embodiments, the absorption layer is made of a material selected from Sn, Ni, Te, and alloys thereof.

[0094] In one embodiment of the present disclosure, an absorber layer with a thickness of 38.5 nm improves the best focus shift by 51.8% in the horizontal direction and by 39.8% in the vertical direction; improves the critical depth of focus (cDOF) by 11.2% in the horizontal direction and by 36.2% in the vertical direction; improves the image logarithmic slope by 1.2% in the horizontal direction; and an example with a TaBN / TaBO absorber layer determined by simulation improves the horizontal-vertical deviation (HV deviation) by 65.5%.

[0095] In one embodiment of the present disclosure, simulations determined that an absorber layer with a thickness of 30.5 nm improved the best focus offset by 64.1% in the horizontal direction and 52.9% in the vertical direction; improved the critical depth of field (cDOF) by 13.1% in the horizontal direction and 24.9% in the vertical direction; improved the image logarithmic slope by 3.5% in the horizontal direction and 1.1% in the vertical direction; and a TaBN / TaBO absorber layer improved the horizontal-vertical deviation (HV deviation) by 77.9%.

[0096] Figures 7 to 10 is a graph showing various exposure parameters simulated over a range of pattern spacings. The different curves represent different thicknesses of the absorber layer according to the present disclosure. In the simulation, the numerical aperture (NA) is 0.33 and a dipole radiation source is used. Figures 7 to 10 In the figure, BSL-H is a horizontal pattern and BSL-V is a vertical pattern. The BSL-H pattern and the BSL-V pattern are initial reference patterns. Pattern A and pattern C are horizontal and vertical patterns, respectively, and have an absorption layer thickness ranging from about 36.5nm to about 40.5nm. Pattern B and pattern D are horizontal and vertical patterns, respectively, and have an absorption layer thickness ranging from 28.5nm to about 32.5nm.

[0097] Figure 7 2 is a diagram showing simulations of pattern spacing and optimal focus according to the present disclosure for an initial reference example (BSL) and examples A, B, C, and D for horizontal and vertical TaBN / TaBO absorber layers. Figure 7 As shown, Examples A, B, C, and D depict significant improvements over Example BSL. The best focus of Examples A, B, C, and D varies less over the pattern spacing range than Example BSL. Examples A, B, C, and D have flatter best focus curves over the entire spacing range.

[0098] Figure 8Simulations of pattern pitch and individual depth of focus (iDOF) according to the present disclosure are shown for a starting reference example (BSL) and examples A, B, C, and D for horizontal and vertical TaBN / TaBO absorber layers. Figure 8 As shown, Examples A, B, C, and D each have a depth of focus comparable to Example BSL.

[0099] Fig. 9 Simulations of pattern spacing and image log-slope (ILS) according to the present disclosure are shown for a starting reference example (BSL) and examples A, B, C, and D for horizontal and vertical TaBN / TaBO absorber layers. Fig. 9 As shown, examples A, B, C, and D are improved at higher pitch densities (lower pitch values) compared to example BSL. ILS is a measure of the steepness of the edge pattern. The slope of image intensity as a function of position (dI / dx) is a measure of the steepness of the transition from light to dark in the image. The image log slope is the slope of the image intensity divided by the intensity: Image log slope = (1 / I)(dI / dx) = dln(I) / dx.

[0100] Fig.10 Simulations of pattern spacing and horizontal-vertical deviation (HV deviation) according to the present disclosure are shown for the initial reference example (BSL) of horizontal and vertical TaBN / TaBO absorber layers and examples E and F. Pattern E has an absorber layer thickness ranging from about 36.5 nm to about 40.5 nm. Pattern F has an absorber layer thickness ranging from about 28.5 nm to about 32.5 nm. Fig.10 As shown, the HV deviations of Example E and Example F are significantly improved compared to Example BSL.

[0101] Fig.11 FIG. 4 is a flow chart of a method 400 for manufacturing an EUV light mask according to an embodiment of the present disclosure. In some embodiments, the mask is a reflective mask for selectively exposing a substrate coated with photoresist to EUV light. In operation S410, a substrate 30 (see FIG. 4 ) is formed on the substrate 30. Figure 3 ) is formed with a plurality of alternately stacked first reflective layers 37 and second reflective layers 39. The substrate 30 is made of a low thermal expansion material, such as titanium dioxide doped silicon oxide in some embodiments. In some embodiments, the first reflective layer 37 is silicon and the second reflective layer 39 is molybdenum.

[0102] In some embodiments, about 30 to about 60 alternating silicon layers and molybdenum layers are formed. In a specific embodiment, about 40 to about 50 alternating silicon layers and molybdenum layers are formed. In some embodiments, the silicon layers and molybdenum layers are formed by chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD), physical vapor deposition (PVD) (sputtering) or any other suitable film forming method. The thickness range of each silicon layer and each molybdenum layer is about 2nm to 10nm. In some embodiments, the thickness of the silicon layer and the molybdenum layer is approximately the same. In other embodiments, the silicon layer and the molybdenum layer are different thicknesses. In one embodiment, the thickness of each silicon layer and each molybdenum layer is about 3nm to about 4nm.

[0103] In operation S420, in some embodiments, a capping layer 40 is then formed on the molybdenum / silicon (Mo / Si) multilayer 35. In some embodiments, the capping layer 40 is composed of ruthenium having a thickness ranging from about 2 nm to about 10 nm. In a specific embodiment, the thickness of the capping layer 40 ranges from about 2 nm to about 4 nm. In a specific embodiment, the thickness of the capping layer 40 is about 3.5 nm. In some embodiments, the capping layer 40 is formed by chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, or any other suitable film forming method.

[0104] Next, in some embodiments, an absorption layer is formed on the cap layer 40 in operation S430. In some embodiments, the absorption layer is made of a material selected from Sn, Ni, Te, Co, In, Sb, and an alloy of Sn, Ni, Te, Co, In, and Sb. In some embodiments, the absorption layer is made of a material selected from Sn, Ni, Te, and an alloy thereof. In some embodiments, the absorption layer has a thickness ranging from about 19.5 nm to about 43.5 nm. In some embodiments, the absorption layer has a thickness ranging from about 25.5 nm to about 35.5 nm. In other embodiments, the absorption layer has a thickness ranging from about 33.5 nm to about 43.5 nm.

[0105] In some embodiments, the absorber layer is formed by chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, or any other suitable film forming method.

[0106] In some embodiments, in operation S440, the absorption layer is then patterned to form an absorption layer 45. In some embodiments, the pattern formed in the absorption layer 45 corresponds to an integrated circuit pattern to be formed on the semiconductor substrate. In some embodiments, the pattern is formed by suitable lithography and etching operations. For example, a photoresist layer is formed on the absorption layer, and the photoresist layer is selectively exposed to actinic radiation. Actinic radiation includes ultraviolet light and deep ultraviolet light, electron beams and ion beams. The photoresist is a positive or negative photoresist. The exposed photoresist layer is then selectively developed using a suitable developer to form a pattern in the photoresist. In some embodiments, a suitable etching operation is used to extend the pattern in the photoresist into the absorption layer. The etching operation can be a wet etching operation or a dry etching operation. In some embodiments, the pattern in the absorption layer exposes the cap layer 40. In some embodiments, the pattern extends into the cap layer 40. After the pattern is formed in the absorption layer, the remaining photoresist is removed by a suitable photoresist stripping solution or a plasma ashing operation to form a patterned absorption layer 45.

[0107] In some embodiments, a black border 65 is formed in operation S450 to define a circuit area to be imaged and a peripheral area not to be imaged. The black border 65 is formed by suitable lithography and etching operations. In some embodiments, the pattern of the black border extends from the surface of the absorption layer 45 into the substrate 10.

[0108] In some embodiments, a conductive layer 60 is formed on the second main surface of the substrate 10, and a plurality of pairs of Mo / Si 35 are formed over the first main surface of the substrate 10 relative to the second main surface. In some embodiments, the conductive layer 60 is made of chromium, chromium nitride, or TaB with a thickness of about 25 nm to about 150 nm. In some embodiments, the conductive layer 60 has a thickness of about 70 nm to about 100 nm. In some embodiments, the conductive layer 60 is formed by chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, or any other suitable film forming method.

[0109] In other embodiments of the present disclosure, Fig.12 As shown in the flowchart, a method 500 is provided for optimizing the absorption layer of the extreme ultraviolet light mask. A plurality of alternating first reflection layers 37 and second reflection layers 39 are formed on the substrate 30 (see Figure 3 In some embodiments, the substrate 30 is made of a low thermal expansion material, such as silicon oxide doped with titanium dioxide. In some embodiments, the first reflective layer 37 is silicon and the second reflective layer 39 is molybdenum.

[0110] About 30 to about 60 alternating silicon layers and molybdenum layers are formed. In a specific embodiment, about 40 to about 50 alternating silicon layers and molybdenum layers are formed. In some embodiments, the silicon layers and molybdenum layers are formed by chemical vapor deposition (CVD), plasma enhanced CVD (PECVD), atomic layer deposition (ALD), physical vapor deposition (PVD) (sputtering) or any other suitable film forming method. The thickness range of each silicon layer and each molybdenum layer is about 2nm to 10nm. In some embodiments, the thickness of the silicon layer and the molybdenum layer is approximately the same. In other embodiments, the silicon layer and the molybdenum layer are different thicknesses. In one embodiment, the thickness of each silicon layer and each molybdenum layer is about 3nm to about 4nm.

[0111] In operation S520, in some embodiments, a capping layer 40 is then formed on the molybdenum / silicon (Mo / Si) multilayer 35. In some embodiments, the capping layer 40 is composed of ruthenium having a thickness ranging from about 2 nm to about 10 nm. In a specific embodiment, the thickness of the capping layer 40 ranges from about 2 nm to about 4 nm. In a specific embodiment, the thickness of the capping layer 40 is about 3.5 nm. In some embodiments, the capping layer 40 is formed by chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, or any other suitable film forming method.

[0112] Next, an absorption layer material is selected in operation S530. In some embodiments, the absorption layer material has a refractive index ranging from about 0.87 to about 1.02, an extinction coefficient ranging from about 0.065 to about 0.085, and a thickness ranging from about 33.5 nm to about 35.5 nm. In other embodiments, the absorption layer material has a refractive index ranging from about 0.87 to about 1.02, an extinction coefficient ranging from about 0.085 to about 0.105, and a thickness ranging from about 25.5 nm to about 35.5 nm.

[0113] In operation S540, an absorption material layer is then formed on the cap layer 40 and / or the plurality of alternately stacked first and second reflection layers 35. In some embodiments, the absorption material layer is made of a material selected from Sn, Ni, Te, Co, In, Sb, and an alloy of Sn, Ni, Te, Co, In, and Sb. In some embodiments, the absorption layer is made of a material selected from Sn, Ni, Te, and an alloy thereof. In some embodiments, the absorption material layer is formed by chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, physical vapor deposition, or any other suitable film forming method.

[0114] In some embodiments, in operation S550, the absorption material layer is then patterned. The pattern formed in the absorption material layer corresponds to the integrated circuit pattern to be formed on the semiconductor substrate. In some embodiments, the pattern is formed by appropriate lithography and etching operations.

[0115] In some embodiments, additional operations are performed on the EUV photomask including forming a backside conductive layer and a black border surrounding the image forming area of ​​the photomask.

[0116] Fig.13 A flow chart of a method 600 for manufacturing a semiconductor device according to an embodiment of the present disclosure is shown. In operation S610, a photoresist layer is formed over a semiconductor substrate. In some embodiments, the semiconductor substrate includes a single crystal semiconductor layer located at least over a surface portion thereof. The substrate may include a single crystal semiconductor material, such as but not limited to Si, Ge, SiGe, GaAs, InSb, GaP, GaSb, InAlAs, InGaAs, GaSbP, GaAsSb, and InP. In a specific embodiment, the substrate is made of crystalline silicon.

[0117] In some embodiments, the photoresist layer comprises a positive or negative photoresist. In some embodiments, the photoresist comprises a photoactive compound, a polymer and a solvent. In some embodiments, the photoactive compound is a photoacid generator and the polymer comprises an acid-labile group.

[0118] In operation S620, the photoresist layer is selectively exposed to actinic radiation through a reflective mask. In some embodiments, the actinic radiation is extreme ultraviolet light. In some embodiments, the reflective mask includes an absorption layer having a refractive index ranging from about 0.87 to about 1.02, an extinction coefficient ranging from about 0.065 to about 0.085, and a thickness ranging from about 33.5 nm to about 35.5 nm. In other embodiments, the absorption layer has a refractive index ranging from about 0.87 to about 1.02, an extinction coefficient ranging from about 0.085 to about 0.105, and a thickness ranging from about 25.5 nm to about 35.5 nm. In some embodiments, a pattern is formed on the absorption layer to form a pattern of an integrated circuit on a substrate coated with photoresist. In some embodiments, the absorption layer is disposed above a plurality of alternating stacked first and second reflective layers covering the substrate.

[0119] In some embodiments, as explained herein, the refractive index N is set to 0.95 in one simulation, and the extinction coefficient K and the absorbing layer thickness T are optimized. In other embodiments of the present disclosure, N, K, and T are optimized simultaneously in a simulation. Fig.14A , Fig. 14B and Fig. 14CDepicted are simulation results for optimizing the reflectivity of an EUV reticle according to one embodiment, the EUV reticle including an absorber layer disposed on a 3.5 nm thick Ru capping layer disposed on more than 40 pairs of 3.0 nm thick Mo layer and 4.0 nm thick Si layer. The absorber layer has a thickness varying from 20 nm to 70 nm, a refractive index varying from 0.85 to 1.0, and an extinction coefficient varying from 0.03 to 0.08. Fig.14A The corresponding reflectivity of the absorption layer with a thickness of 53 nm is shown when the refractive index and the extinction coefficient are changed. Fig. 14B The variation of the thickness T of the absorption layer with respect to the reflectivity at various refractive indices at the extinction coefficient K=0.605 is shown. Fig. 14C The variation of the absorber layer thickness T and reflectivity under various extinction coefficients of refractive index N = 0.9445 is shown. When the absorber layer thickness T is about 53 nm, the refractive index N ranges from about 0.944 to about 0.945, and the extinction coefficient K ranges from about 0.060 to about 0.061, the simulation shows that a minimum reflectivity is 2.00×10 -5 .

[0120] refer to Fig.14A and Fig. 14B The simulation of the EUV mask discussed is as follows Fig.15A As shown in , the minimum reflectivity corresponding to the thickness of each absorption layer is determined within the range of NK. Fig.15A The inset shows the NK value corresponding to the minimum reflectivity, and the dashed line shows the overall minimum reflectivity at the absorption layer thickness T of about 53 nm. Fig. 15B The table shows the simulation results of NKT2 = (0.944 to 0.945, 0.060 to 0.061, 34.5 to 38.5) and NKT3 = (0.900 to 0.902, 0.060 to 0.061, 30 to 34) compared with the overall reflectivity minimum range NKT1 = (0.944 to 0.945, 0.060 to 0.061, 51 to 55). L / SV refers to vertical line and space (Line / Space); L / SH refers to horizontal line and space; and C / H refers to contact hole. L / S, P26, 13k13: refers to vertical line and space with a pitch of 26nm, the first 13 (nm) is the width at the mask. The second 13 (nm) is the width at the wafer. C / H, P32, 17k16: refers to contact holes with a pitch of 32 (nm), a width of 17nm at the mask and a width of 16nm at the wafer. The overall reflectivity minimum is the minimum of the entire curve, with many local minima.

[0121] Figures 16A to 16H as well as Figures 17A to 17HThe simulation optimization results for the EUV mask are shown respectively, where L / SV is used for the vertical pattern of the EUV mask and L / SH is used for the horizontal pattern. Fig.16A and Fig.17A Plot the logarithmic slope of the graph. Fig. 16B and Fig. 17B The optimum focus shift is plotted. Fig. 16C and Fig. 17C Depth of field is shown. Fig.16D and Fig.17D The mask error amplification factor is shown. Fig.16E , Fig.16F , Figure 16G and Fig.16H The exposure defocus and bulk image threshold intensity of the EUV mask initial reference example BSL and examples NKT1, NKT2 and NKT3 are shown, wherein the L / SV of the pattern in the vertical direction is NKT1=(0.944-0.945, 0.060-0.061, 51-55), NKT2=(0.944-0.945, 0.060-0.061, 34.5-38.5) and NKT3=(0.900-0.902, 0.060-0.061, 30-34). Fig.17E , Fig.17F , Figure 17G and Fig.17H The exposure defocus and rough image critical intensity of the initial reference example of the EUV mask are plotted, where the L / SH of the pattern in the horizontal direction are NKT1=(0.944-0.945, 0.060-0.061, 53), NKT2=(0.944-0.945, 0.060-0.061, 34.5-38.5) and NKT3=(0.900-0.902, 0.060-0.061, 30-34).

[0122] In some embodiments, the extreme ultraviolet light mask includes a cap layer disposed above a plurality of pairs of reflective layers, and a patterned absorption layer disposed above the cap layer. In some embodiments, the absorption layer has a refractive index ranging from about 0.895 to about 0.950. In other embodiments, about 0.90 to about 0.945. In some embodiments, the refractive index is about 0.901. In some embodiments, the refractive index is about 0.9445. In some embodiments, the absorption layer has an extinction coefficient ranging from about 0.0600 to about 0.0610, and an extinction coefficient ranging from about 0.0603 to about 0.0607 in other embodiments. In some embodiments, the extinction coefficient of the absorption layer is about 0.0605. In some embodiments, the thickness of the absorption layer ranges from about 30nm to about 39nm. In other embodiments, the thickness of the absorption layer ranges from about 50nm to about 55nm. In one embodiment, the thickness of the absorption layer is about 31nm to about 37nm. In some embodiments, the thickness of the absorption layer is about 32nm. In some embodiments, the thickness of the absorption layer is about 36.5nm. In some embodiments, the thickness of the absorption layer is about 53nm.

[0123] The EUV mask and its manufacturing method disclosed herein provide a method for reducing the 3D effect of the mask by reducing the thickness of the absorption layer and reducing the reflectivity of the absorption layer. The EUV mask and its manufacturing method disclosed herein improve EUV lithography performance, including improving horizontal and vertical deviation, improving optimal focus, and improving depth of field.

[0124] One embodiment of the present disclosure is an extreme ultraviolet light mask, comprising an absorption layer having a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.065 to 0.085, and a thickness ranging from 33.5 nm to 43.5 nm. In one embodiment, the absorption layer has a refractive index ranging from 0.90 to 1.00. In one embodiment, the absorption layer has a refractive index of 0.95. In one embodiment, the absorption layer has an extinction coefficient ranging from 0.070 to 0.080. In one embodiment, the extinction coefficient of the absorption layer is 0.075. In one embodiment, the absorption layer has a thickness ranging from 39 nm to 43 nm. In one embodiment, the thickness of the absorption layer is 38.5 nm. In one embodiment, the absorption layer is made of a material selected from Sn, Ni, Te, and an alloy of Sn, Ni, and Te.

[0125] Another embodiment of the present disclosure is an EUV light mask, comprising an absorption layer having a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.085 to 0.105, and a thickness in the range of 25.5 nm to 35.5 nm. In one embodiment, the absorption layer has a refractive index in the range of 0.90 to 1.00. In one embodiment, the absorption layer has a refractive index of 0.95. In one embodiment, the absorption layer has an extinction coefficient in the range of 0.090 to 0.100. In one embodiment, the extinction coefficient of the absorption layer is 0.095. In one embodiment, the absorption layer has a thickness in the range of 27.5 nm to 31.5 nm. In one embodiment, the thickness of the absorption layer is 30.5 nm.

[0126] Another embodiment of the present disclosure is an extreme ultraviolet light mask, including an absorption layer having a refractive index ranging from 0.895 to 0.950, an extinction coefficient ranging from 0.0600 to 0.0610, and a thickness ranging from 30nm to 39nm or 50nm to 55nm. In one embodiment, the thickness ranges from 30 to 34nm. In one embodiment, the thickness ranges from 34.5nm to 38.5nm. In one embodiment, the thickness ranges from 51 to 55nm. In one embodiment, the absorption layer has a refractive index ranging from 0.944 to 0.945. In one embodiment, the absorption layer has a refractive index ranging from 0.900 to 0.902. In one embodiment, the absorption layer has an index of refractive index ranging from 0.90 to 0.945, and has an extinction coefficient of 0.0605. In one embodiment, the absorption layer has a refractive index of 0.9445 and a thickness of 36.5nm. In one embodiment, the absorption layer has a refractive index of 0.901 and a thickness of 32nm. In one embodiment, the absorption layer has a refractive index of 0.9445 and a thickness of 53 nm.

[0127] Another embodiment of the present disclosure is a method for manufacturing an extreme ultraviolet light mask, including forming a plurality of alternately stacked first and second reflective layers on a substrate. An absorption layer is formed on the plurality of alternately stacked first and second reflective layers. The absorption layer has a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.065 to 0.085, and a thickness ranging from 33.5 nm to 43.5 nm. In one embodiment, the method includes forming a cap layer between the plurality of alternately stacked first and second reflective layers and the absorption layer. In one embodiment, the cap layer is composed of ruthenium. In one embodiment, the plurality of alternately stacked first and second reflective layers include a plurality of pairs of molybdenum layers and silicon layers. In one embodiment, the absorption layer has a refractive index ranging from 0.90 to 1.00. In one embodiment, the absorption layer has a refractive index of 0.95. In one embodiment, the absorption layer has an extinction coefficient ranging from 0.070 to 0.080. In one embodiment, the absorption layer has an extinction coefficient of 0.075. In one embodiment, the thickness of the absorption layer is 35.5 nm to 39.5 nm. In one embodiment, the thickness of the absorption layer is 38.5 nm. In one embodiment, the absorption layer is made of a material selected from Sn, Ni, Te, and an alloy of Sn, Ni, and Te.

[0128] Another embodiment of the present disclosure is a method for manufacturing an extreme ultraviolet light mask, including forming a plurality of alternately stacked first and second reflective layers above a substrate. An absorption layer is formed above the plurality of alternately stacked first and second reflective layers. The absorption layer has a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.085 to 0.105, and a thickness ranging from 25.5 nm to 35.5 nm. In one embodiment, the method includes forming a cap layer between the plurality of alternately stacked first and second reflective layers and the absorption layer. In one embodiment, the cap layer is made of ruthenium. In one embodiment, the plurality of alternately stacked first and second reflective layers include a plurality of pairs of molybdenum layers and silicon layers. In one embodiment, the absorption layer has a refractive index ranging from 0.90 to 1.0. In one embodiment, the absorption layer has a refractive index of 0.95. In one embodiment, the absorption layer has an extinction coefficient ranging from 0.090 to 0.100. In one embodiment, the extinction coefficient of the absorption layer is 0.095. In one embodiment, the absorption layer has a thickness ranging from 27.5 nm to 31.5 nm. In one embodiment, the thickness of the absorption layer is 30.5 nm.

[0129] Another embodiment of the present disclosure is a method for optimizing an absorption layer of an extreme ultraviolet light mask, comprising forming a plurality of alternately stacked first and second reflection layers above a substrate. The absorption material layer has a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.065 to 0.085, and a thickness ranging from 33.5 nm to 43.5 nm. The absorption material layer is formed above the plurality of alternately stacked first and second reflection layer stacks.

[0130] Another embodiment of the present disclosure is a method for optimizing an absorption layer of an EUV light mask, comprising forming a plurality of alternately stacked first and second reflection layers on a substrate, selecting an absorption material layer having a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.085 to 0.105, and a thickness ranging from 25.5 nm to 35.5 nm, and forming the absorption material layer on the plurality of alternately stacked first and second reflection layers.

[0131] Another embodiment of the present disclosure is a method of manufacturing a semiconductor device, comprising forming a photoresist layer on a semiconductor substrate, and selectively exposing the photoresist layer to actinic radiation reflected from a reflective mask. The reflective mask includes: an absorption layer having a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.065 to 0.085, and a thickness ranging from 33.5 nm to 43.5 nm.

[0132] Another embodiment of the present disclosure is a method of manufacturing a semiconductor device, comprising forming a photoresist layer on a semiconductor substrate, and selectively exposing the photoresist layer to actinic radiation reflected from a reflective mask. The reflective mask includes: an absorption layer having a refractive index ranging from 0.87 to 1.02, an extinction coefficient ranging from 0.085 to 0.105, and a thickness ranging from 25.5 nm to 35.5 nm.

[0133] Another embodiment of the present disclosure is a method of manufacturing a semiconductor device, comprising forming a photoresist layer on a semiconductor substrate, and selectively exposing the photoresist layer to actinic radiation reflected from a reflective mask. The reflective mask includes: an absorption layer having a refractive index ranging from 0.895 to 0.950, an extinction coefficient ranging from 0.0600 to 0.0610, and a thickness ranging from 30 nm to 39 nm or 50 nm to 55 nm.

[0134] Another embodiment of the present disclosure is an EUV mask, comprising a plurality of alternately stacked first reflective layers and second reflective layers disposed on a substrate; a ruthenium capping layer disposed on the alternately stacked first reflective layers and second reflective layers; an absorption layer having a pattern disposed on the ruthenium capping layer; and a black border. The absorption layer has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption layer is 2.00×10 -5 , wherein the material of the absorption layer is an alloy material containing Te. A black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate. In some embodiments, the absorption layer is made of an alloy material selected from at least two of Sn, Ni, and Te.

[0135] Another embodiment of the present disclosure is an extreme ultraviolet light mask, comprising a plurality of alternately stacked first reflective layers and second reflective layers disposed on a substrate; a ruthenium capping layer disposed on the alternately stacked first reflective layers and second reflective layers; an absorption layer having a pattern disposed on the ruthenium capping layer; and a black border. The absorption layer has a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.085 to 0.105, and a thickness in the range of 28.5 nm to 32.5 nm, wherein the material of the absorption layer is an alloy material containing Te. The black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate. In some embodiments, the absorption layer has a refractive index of 0.95. In some embodiments, the absorption layer has an extinction coefficient of 0.095. In some embodiments, the absorption layer has a thickness of 30.5 nm.

[0136] Another embodiment of the present disclosure is a method for manufacturing an EUV light mask, comprising forming a plurality of alternately stacked first reflective layers and second reflective layers on a substrate; forming a ruthenium capping layer on the plurality of alternately stacked first reflective layers and second reflective layers; forming an absorption film on the ruthenium capping layer; forming a pattern in the absorption film; forming a black border surrounding the pattern and disposed in the absorption film by photolithography and etching operations, wherein the pattern of the black border extends from the surface of the absorption film into the substrate. The absorption film has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption film is 2.00×10 -5 , wherein the material of the absorption film is an alloy material containing Te. In some embodiments, the ruthenium capping layer is exposed from the opening of the pattern of the absorption film. In some embodiments, the thickness of the ruthenium capping layer is 3.5 nm. In some embodiments, the absorption film is made of an alloy material selected from at least two of Sn, Ni, and Te.

[0137] The foregoing summarizes the features of many embodiments or examples, so that those with ordinary knowledge in the art can better understand the present disclosure from various aspects. Those with ordinary knowledge in the art should understand and easily design or modify other processes and structures based on the present disclosure, and thereby achieve the same purpose and / or achieve the same advantages as the embodiments introduced herein. Those with ordinary knowledge in the art should also understand that these equivalent structures do not deviate from the spirit and scope of the invention of the present disclosure. Various changes, substitutions and modifications can be made to the present disclosure without departing from the spirit and scope of the invention of the present disclosure.

Claims

1. An extreme ultraviolet light mask, characterized in that: Include: A plurality of alternately stacked first reflective layers and second reflective layers are disposed above a substrate; a ruthenium capping layer, disposed above the plurality of alternately stacked first reflecting layers and second reflecting layers; An absorption layer having a pattern is disposed on the ruthenium cap layer, wherein the absorption layer has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption layer is 2.00×10 -5 , wherein the material of the absorption layer is an alloy material containing Te; as well as A black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate.

2. The EUV light mask according to claim 1, wherein: The absorption layer is made of an alloy material of at least two selected from Sn, Ni, and Te.

3. An extreme ultraviolet light mask, characterized in that: Include: A plurality of alternately stacked first reflective layers and second reflective layers are disposed above a substrate; a ruthenium capping layer, disposed above the plurality of alternately stacked first reflecting layers and second reflecting layers; an absorption layer having a pattern is disposed on the ruthenium cap layer, wherein the absorption layer has a refractive index in the range of 0.87 to 1.02, an extinction coefficient in the range of 0.085 to 0.105, and a thickness in the range of 28.5 nm to 32.5 nm, wherein the material of the absorption layer is an alloy material containing Te; and A black border is disposed around the pattern and in the absorption layer, wherein the pattern of the black border extends from the surface of the absorption layer into the substrate.

4. The EUV light mask according to claim 3, wherein: The absorption layer has a refractive index of 0.

95.

5. The EUV light mask according to claim 3, wherein: The absorption layer has an extinction coefficient of 0.

095.

6. The EUV light mask according to claim 3, characterized in that: The absorption layer has a thickness of 30.5 nm.

7. A method for manufacturing an extreme ultraviolet light mask, characterized in that: Include: Forming a plurality of alternately stacked first reflection layers and second reflection layers on a substrate; forming a ruthenium capping layer on the plurality of alternately stacked first reflective layers and second reflective layers; forming an absorption film on the ruthenium capping layer; forming a pattern in the absorption film; as well as A black border is formed by photolithography and etching operations to surround the pattern and is disposed in the absorption film, wherein the pattern of the black border extends from the surface of the absorption film into the substrate, The absorption film has a refractive index in the range of 0.944 to 0.945, an extinction coefficient in the range of 0.060 to 0.061, and a thickness of 53 nm, so that the minimum reflectivity of the absorption film is 2.00×10 -5 , wherein the material of the absorption film is an alloy material containing Te.

8. The method for manufacturing an EUV light mask according to claim 7, wherein: The ruthenium capping layer is exposed from the opening of the pattern of the absorption film.

9. The method for manufacturing an EUV light mask according to claim 7, wherein: The thickness of the ruthenium capping layer is 3.5 nm.

10. The method for manufacturing an EUV light mask according to claim 7, wherein: The absorption film is made of an alloy material of at least two selected from Sn, Ni, and Te.

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