Methods for patterning

Abstract

Embodiments of the present invention disclose a method for patterning. The embodiments utilize photolithography to form a patterned target layer. After forming a patterned mandrel layer and a spacer layer above the patterned mandrel layer, a photomask underlayer is deposited using chemical vapor deposition to form an amorphous carbon film. The upper layer of the photomask is used to pattern the underlayer to form openings for the conversion material. The conversion material is deposited in the openings of the underlayer, which provides both masking and stencil functions for the conversion material.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of semiconductor technology, and more specifically, to a method for patterning. Background Technology

[0002] To form integrated circuits on a wafer, a photolithography process is used. A typical photolithography process involves applying photoresist and defining a pattern on the photoresist. The pattern in the photoresist is defined within a photomask, and is further defined by transparent or opaque portions of the photomask. The patterned photoresist is then transferred to the underlying component via an etching step, where the patterned photoresist serves as an etching mask. After the etching step, the patterned photoresist is removed.

[0003] As integrated circuits continue to shrink, the high aspect ratio stacks used in photo-patterning techniques can lead to poor resistance to wiggling during pattern transfer to amorphous silicon substrates. In turn, line wiggling can cause pattern defects. Pattern defects and line wiggling can lead to metal pattern line breakage and ultimately pattern failure. Summary of the Invention

[0004] According to one aspect of the present invention, a method for patterning is provided, comprising: forming a spacer layer over a patterned mandrel layer; forming an insulating layer over the spacer layer, the insulating layer comprising amorphous carbon; patterning the insulating layer to form openings in the insulating layer, the openings exposing portions of the spacer layer disposed between two mandrels of the patterned mandrel layer; depositing a conversion material in the openings; removing the insulating layer, the conversion material, and the exposed horizontal portions of the spacer layer, wherein portions of the conversion material retain portions of the spacer layer between the two mandrels of the patterned mandrel layer; removing one or more mandrels from the patterned mandrel layer; and etching a target layer based on a pattern determined by a combination of the patterned mandrel layer, the spacer layer, and the conversion material.

[0005] According to another aspect of the present invention, a method for patterning is provided, comprising: depositing a conformal spacer layer over a mandrel assembly; depositing a bottom layer of a photomask over the spacer layer, the bottom layer of the photomask comprising carbon, hydrogen, and oxygen, the bottom layer having less than 5% oxygen; depositing an upper layer of the photomask over the bottom layer, the upper layer comprising photosensitive photoresist; developing the upper layer to form a first pattern in the upper layer; transferring the first pattern to the bottom layer, the first pattern exposing a first portion of the spacer layer; depositing a protective layer over the bottom layer and over the first portion of the spacer layer; removing the bottom layer to expose the spacer layer except for the first portion of the spacer layer located below the protective layer; etching the spacer layer to remove horizontal portions of the spacer layer except for the first portion of the spacer layer located below the protective layer; etching the mandrel assembly to remove one or more mandrels; and etching a target layer located below the spacer layer to form a second pattern in the target layer, the second pattern being based on using the remaining spacer layer including the first portion of the spacer layer as an etching mask.

[0006] According to another aspect of the present invention, a method for patterning is provided, comprising: depositing a bottom mask layer over a target layer using a hydrocarbon precursor; depositing a top mask layer over the bottom mask layer; patterning the top mask layer by a photolithography process to form a patterned top mask; etching a bottom mask layer based on the patterned top mask to form a patterned bottom mask, the patterned bottom mask including a first opening; depositing a conversion material in the first opening; removing the bottom mask layer and thinning the conversion material, a first portion of the conversion material being disposed on a spacer layer between two mandrels of a mandrel layer; etching the spacer layer to remove a horizontal portion of the spacer layer other than the horizontal portion of the spacer layer below the first portion of the conversion material; transferring a pattern of the remaining spacer layer, the remaining mandrel layer, and the remaining conversion material to the mask layer; and etching the target layer based on the pattern of the mask layer. Attached Figure Description

[0007] The various aspects of the invention can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with standard industrial practice, the various components are not drawn to scale and are for illustrative purposes only. In fact, for clarity of discussion, the dimensions of the various components may be arbitrarily increased or decreased.

[0008] Figure 1A and Figures 1B to 27A and Figure 27B Cross-sectional and top views are shown at an intermediate stage in the formation of a semiconductor device. Detailed Implementation

[0009] The following disclosure provides numerous different embodiments or examples for implementing various features of the invention. Specific embodiments or examples of components and arrangements are described below to simplify the invention. Of course, these are merely examples and not intended to be limiting. For example, in the following description, forming a first component above or on a second component can include embodiments where the first and second components are in direct contact, and can also include embodiments where an additional component can be formed between the first and second components, such that the first and second components are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.

[0010] Furthermore, for ease of description, this document may use spacing terms such as “below,” “under,” “lower,” “above,” “upper,” etc., to describe the relationship between one element or component and another, as shown in the figures. In addition to the orientations shown in the figures, spacing terms are intended to include different orientations of the device during use or operation. The device may be positioned in other ways (rotated 90 degrees or in other orientations), and the spacing descriptors used herein may be interpreted accordingly.

[0011] The self-aligned patterning process uses a photo-patterned mandrel layer. Due to the pattern loading effect, the mandrel layer is typically patterned using regularly spaced patterns. The mandrel layer is then covered by a conformal spacer layer, which is anisotropically etched to form the sidewall spacers of the mandrel. The mandrel is then removed, leaving an etched mask with a high density and a small pitch between mask structures. This process can be tailored to form specific patterns by including a conversion material on the spacer layer, which protects portions of the spacer layer from etching and substantially restores portions of the mandrel layer, allowing the regularly spaced pattern to be adjusted or customized to change the final pattern. A photomask structure can be used when forming this conversion material. The example process utilizes an amorphous carbon underlayer deposited via a CVD process. The resulting film allows for greater flexibility in depositing material layers (e.g., other layers including a photomask and conversion material) on the underlayer. For example, morphology problems that might arise from using spin-coated carbon or other spin-coated materials are resolved because CVD deposition and the amorphous carbon material result in an improved and more stable underlayer. The overlay can be deposited at higher temperatures, allowing for the use of higher quality films. Some embodiments utilize a three-layer mask structure, while others utilize a two-layer mask structure including a photoresist layer on a metal oxide layer.

[0012] Figure 1A and Figures 1B to 27A and Figure 27BCross-sectional and top views are shown of an intermediate stage in forming components in a target layer of a device according to some embodiments. Figures ending in "A" illustrate cross-sectional views of portions of the structure, and figures ending in "B" illustrate corresponding top views of portions of the structure. Figure 1A and Figure 1B The structure shown can be a portion of a wafer on which many devices are formed simultaneously, or it can be a single device.

[0013] Figure 1A and Figure 1B Workpiece 100 is shown, comprising a substrate 10 and an overlay. The substrate 10 may be formed of a semiconductor material such as silicon, silicon-germanium, etc. In some embodiments, the substrate 10 is a crystalline semiconductor substrate, such as a crystalline silicon substrate, a crystalline silicon-carbon substrate, a crystalline silicon-germanium substrate, a III-V compound semiconductor substrate, etc. In one embodiment, the substrate 10 may comprise doped or undoped bulk silicon, or an active layer comprising a silicon-on-insulator (SOI) substrate. Typically, an SOI substrate comprises a layer of semiconductor material such as silicon, germanium, silicon-germanium, or combinations thereof, such as silicon-germanium-on-insulator (SGOI). Other substrates, including multilayer substrates, gradient substrates, or mixed-orientation substrates, may be used.

[0014] In some embodiments, the illustrated structure is a portion without an interposer layer containing active or passive devices, while in other embodiments, the illustrated structure may include active and / or passive devices disposed therein. In some embodiments, a device (e.g., transistor 11) may be formed on or within the top surface of substrate 10. Active devices may include a variety of active devices, such as transistors, while passive devices may include devices such as capacitors, resistors, inductors, etc., which may be used together to generate the desired structural and functional portions of the design. Active and passive devices may be formed within or on substrate 10 using any suitable method. For example, a device may be transistor 11, which includes a gate electrode 12, a gate spacer 13, and a source / drain region 14. Gate and source / drain contacts 15 may be used to electrically couple to transistor 11. Transistor 11 may be a fin or planar field-effect transistor (FET) and may be an n-type or p-type transistor or a portion of complementary metal-oxide-semiconductor (CMOS). The dielectric layer 16 may include one or more layers of dielectric material, wherein the gate and source / drain contact structures 15 are electrically coupled to active and passive devices.

[0015] A metallization structure 21 is formed over a substrate 10. The metallization structure 21 includes a dielectric layer 22 in which components 24 are formed. The metallization structure 21 can be an interconnect layer or a redistribution structure that may have additional layers. For example, the metallization structure 21 may include a dielectric layer 22, such as an intermetallic dielectric (IMD) layer or an interlayer dielectric (ILD) layer, which may include a dielectric material having a low dielectric constant (k value) of, for example, less than 3.8, less than about 3.0, or less than about 2.5, and the metallization structure 21 may include components 24. The dielectric layer 22 of the metallization structure 21 may be formed of phosphosilicate glass (PSG), borosilicate glass (BSG), doped phosphosilicate glass (BPSG), fluorine-doped silicate glass (FSG), tetraethyl orthosilicate (TEOS), Black Diamond (a registered trademark of Applied Materials), carbon-containing low-k dielectric materials, hydrosilicates (Hydrogen Silses Quioxane, HSQ), methylsiloxane (MSQ), etc.

[0016] Metallization structure 21 (comprising one or more layers) is formed over substrate 10 and devices and is designed to connect various devices to form functional circuitry for circuit design. In one embodiment, metallization structure 21 is formed from alternating layers of dielectric and conductive materials and can be formed by any suitable process (e.g., deposition, damascene, dual damascene, etc.). In one embodiment, one to four metallization layers may be present, separated from substrate 10 by at least one interlayer dielectric (ILD), but the exact number of layers depends on the design.

[0017] The conductive component 24 may include a metal line 24A and a conductive via 24B. The metal line 24A may be formed in the upper portion of the layer of the metallized structure 21 and may be used for signal routing. The conductive via 24B may extend through the dielectric layer 22 to contact a lower layer component such as source / drain contacts 15. In embodiments, the conductive component 24 may be a material such as copper formed using, for example, a damascene or dual damascene process to form an opening within the dielectric layer 22, fill and / or overfill the opening with a conductive material such as copper or tungsten, and perform a planarization process to embed the conductive component 24 within the dielectric layer 22. However, any suitable material and any suitable process may be used to form the conductive component 24. In some embodiments, a barrier layer 25 may surround the conductive component 24 and may serve as a diffusion barrier layer to prevent unwanted elements (such as copper) from diffusing into the surrounding dielectric material of the dielectric layer 22, for example, if the dielectric material of the dielectric layer 22 is a low-k dielectric material. In some embodiments, the conductive component 24 may be a die contact.

[0018] The etch stop layer (ESL) 26 may include a dielectric material such as alumina, silicon carbide, silicon nitride, etc. ESL 26 may be formed from nitrides, silicon-carbon substrate materials, carbon-doped oxides, and / or combinations thereof. ESL 26 may be formed from a metallic material. In some embodiments, ESL 26 may also serve as an anti-reflective coating to aid subsequent patterning. Formation methods include plasma-enhanced chemical vapor deposition (PECVD) or other methods such as high-density plasma-enhanced chemical vapor deposition (HDPCVD), atomic layer deposition (ALD), low-pressure chemical vapor deposition (LPCVD), physical vapor deposition (PVD), etc. According to some embodiments, ESL 26 also serves as a diffusion barrier layer to prevent unwanted elements (such as copper) from diffusing into the subsequently formed low-k dielectric layer. ESL 26 may include carbon-doped oxide (CDO), carbon-doped silicon oxide (SiOC), or oxygen-doped carbide (ODC). ESL 26 may also be formed from nitrogen-doped silicon carbide (NDC).

[0019] Figure 1A and Figure 1B The diagram further illustrates a dielectric layer 28 formed over the ESL 26. According to some embodiments of this disclosure, dielectric layer 28 is formed of a low-k dielectric material having a dielectric constant (k value) lower than about 3.0, about 2.5, or even lower. Dielectric layer 28 can be formed using a material selected from the same set of candidate materials used to form dielectric layer 22. When selected from the same set of candidate materials, the materials of dielectric layers 22 and 28 can be the same or different from each other. According to some embodiments, dielectric layer 28 is a low-k dielectric layer containing silicon and carbon. According to embodiments of this disclosure, dielectric layer 28 may also be referred to as target layer 28, which will have openings formed therein according to a plurality of patterns and filled with metal wires and plugs.

[0020] In some embodiments, a mask 30 is present above the low-k dielectric layer 28. In some embodiments, the mask 30 may be a dielectric hard mask and may be referred to as a dielectric hard mask 30, which may be formed of silicon oxide (such as silicon oxide formed of tetraethyl orthosilicate (TEOS), nitrogen-free antireflective coating (NFARC, which is an oxide), silicon carbide, silicon oxynitride, etc. Formation methods include plasma-enhanced chemical vapor deposition (PECVD), high-density plasma (HDP) deposition, etc.

[0021] A mask 32 is formed over a mask 30 or dielectric layer 28. In some embodiments, the mask 32 may be a hard mask and may also be referred to as a hard mask 32. In some embodiments, the hard mask 32 is a metallic hard mask and may comprise one or more metals, such as titanium (Ti) or tantalum (Ta). In some embodiments, the metal of the hard mask 32 may be in the form of a metal nitride, such as titanium nitride (TiN) or tantalum nitride (TaN). In some embodiments, the hard mask 32 is formed of tungsten-doped carbide (WDC, also known as tungsten-doped silicon carbide). In some embodiments, the hard mask 32 may be formed of a nonmetallic nitride such as silicon nitride, an oxynitride such as silicon oxynitride, etc. Methods for forming the hard mask 32 include physical vapor deposition (PVD), radio frequency PVD (RFPVD), atomic layer deposition (ALD), etc.

[0022] A dielectric mask layer 34 is formed over the mask 32. In some embodiments, the mask layer 34 may be a hard mask and may be referred to as mask layer 34. The mask layer 34 may be formed using processes and materials similar to those discussed above with respect to the dielectric hard mask 30, and may be formed using methods selected from the same set of candidate methods for forming the dielectric hard mask 30. Mask layers 30 and 34 may be formed of the same material, or may include different materials. In some embodiments, the mask layer 34 may be patterned after deposition to expose portions of the underlying hard mask 32. In such embodiments, the mask layer 34 may be used to etch the underlying target layer 28 to different depths.

[0023] A mandrel layer 36 is formed over the mask layer 34. In some embodiments, the mandrel layer 36 is formed of amorphous silicon or other materials that have high etch selectivity with the underlying mask layer 34. The mandrel layer 36 may have approximately to approximately Such as The thickness can be determined using any suitable process, such as CVD or PECVD. After the mandrel layer 36 is patterned as described below, a conversion material can be selectively deposited on it to provide flexibility in patterning the target layer 28. The combination of the mandrel, self-aligned mask, and conversion material will be used in a subsequent process for self-aligned patterning, which will result in the patterning of the target layer 28.

[0024] Still referencing Figure 1A and Figure 1BThree layers are formed on the mandrel layer 36, comprising a bottom layer 38, an intermediate layer 40 above the bottom layer 38, and an upper layer 42 (also referred to as the top layer) above the intermediate layer 40. The bottom layer 38 can be formed of an organic material, such as a polymeric photoresist material, like sacrificial carbon or spin-coated carbon. In some embodiments, the process temperature during the deposition of the bottom layer 38 can be between about 100°C and 250°C. The stress of the bottom layer 38 can be between about 0 MPa and about 50 MPa. The hardness of the bottom layer 38 can be between about 0 GPa and 1 GPa, while the modulus can be between about 9 GPa and 15 GPa. The density of the bottom layer 38 can be between about 0.9 g / cm³. 3 and 1.3g / cm 3 Between. The material composition of the bottom layer 38 can be 76.4% carbon, 4.5% hydrogen and 19.1% oxygen by molecular weight.

[0025] The intermediate layer 40 may comprise an inorganic material, which may be a carbide (such as silicon carbide), a nitride (such as silicon nitride), an oxide oxynitride (such as silicon oxynitride), or an oxide (such as silicon oxide), such as spin-coated glass. The upper layer 42 may be formed of an organic photoresist material such as a polymer. The intermediate layer 40 has high etch selectivity relative to the upper layer 42 and the bottom layer 38, and therefore the upper layer 42 serves as a patterned etch mask for the intermediate layer 40, and the intermediate layer 40 serves as a patterned etch mask for the bottom layer 38.

[0026] Each of the three layers can be formed using a suitable process. In some embodiments, the bottom layer 38, the middle layer 40, and the top layer 42 can each be formed by a spin coating process, or alternatively by any suitable deposition process.

[0027] The thickness of the bottom layer is approximately and Between. The thickness of the intermediate layer of 40 can be approximately and Between. The thickness of the upper layer 42 can be approximately and Between. Although example ranges and thicknesses of the layers are provided, other thicknesses of these layers can be used.

[0028] exist Figure 2A and Figure 2B In this process, after the upper layer 42 is formed, the upper layer 42 is patterned using an acceptable photolithography technique to form a patterned upper layer 142, for example, by exposing the upper layer 42 through a photomask and developing the upper layer 42 to remove portions of the upper layer 42 that are exposed to light or not exposed to light (depending on whether a positive or negative photomask is used). The patterned upper layer 42 includes openings 44 located therein.

[0029] exist Figure 3A and Figure 3B In the process, intermediate layer 40 is etched to form a patterned intermediate layer 140, which may also be referred to as intermediate layer 140. A patterned upper layer 142 is then used. Figure 2A and Figure 2B The intermediate layer 40 is etched using an etch mask, and the pattern of the patterned upper layer 142 is transferred to the intermediate layer 40 to create the patterned intermediate layer 140. During the patterning of the intermediate layer 140, the upper layer 142 may be partially or completely consumed. Etching the intermediate layer 40 results in an opening 46 extending from the opening 44 in the patterned intermediate layer 140. Any suitable etching technique can be used, such as wet etching or dry etching using an etchant selective to the material of the intermediate layer 140.

[0030] exist Figure 4A and Figure 4B In the middle, the bottom layer 38 is then etched to form a patterned bottom layer 138, which can also be referred to as bottom layer 138. An intermediate layer 140 is then used. Figure 3A and Figure 3B The underlying layer 38 is etched using an etch mask, and the pattern of the intermediate layer 140 is transferred to the underlying layer 38 to produce a patterned underlying layer 138. The underlying layer 138 has an opening 48 extending from the opening 46. Figure 3A If the upper layer 142 is not fully consumed during the patterning of the intermediate layer 140, then the upper layer 142 will be fully consumed during the patterning of the lower layer 38. In process variations, the opening 48 may be tapered or may have vertical sidewalls. Any suitable etching technique may be used, such as wet or dry etching using an etchant selective for the material of the lower layer 138. For example, in some embodiments, the etchant may be an O2-based or N2 / H2-based etchant gas used in an etching chamber with other process gases.

[0031] Figure 5A and Figure 5B It shows Figure 4A and Figure 4B Anisotropic etching of the mandrel layer 36 is performed to form a patterned mandrel layer 136, which may also be referred to as the mandrel 136. The mandrel layer 136 is etched using a patterned underlayer 138 as an etching mask, thereby transferring the pattern of the underlayer 138 to the mandrel layer 36 to produce the patterned mandrel layer 136. The patterned mandrel layer 136 has an opening 50 extending from the opening 48. Figure 4AThe etching technique may include dry etching using a suitable etchant. In some embodiments, the etchant selected for etching the patterned mandrel layer 136 may be a fluorine-free etchant, such as a chlorine-based etchant. In other embodiments, other etchants, including fluorine-based etchants, may be used. The mask layer 34 beneath the patterned mandrel layer 136 may serve as an etch stop layer for etching through the mandrel layer 36. An opening 50 is formed due to the etching of the patterned mandrel layer 136. After etching the patterned mandrel layer 136, the underlying layer 138 may be removed by an ashing process.

[0032] exist Figure 6A and Figure 6B In this process, spacer layer 52 can be deposited over patterned mandrel layer 136. Spacer layer 52 can be made of a suitable oxide or nitride insulating or dielectric material, deposited using a deposition technique suitable for forming substantially conformal layers (e.g., such that the horizontal and vertical portions of spacer layer 52 vary by 25% or less). Such deposition techniques can include, for example, PECVD, HDPCVD, ALD, CVD, LPCVD, PVD, etc. Figure 6B Includes the dashed line, which represents the lower portion of the spacer layer 52.

[0033] Next, as Figure 7A and Figure 7B As shown, the bottom layer 56 of the mask structure can be deposited in the opening 54 (see Figure 56). Figure 6A The spacer layer 52 is neutralized above the underlayer 56. The underlayer 56 can serve as part of a masking structure comprising two or three layers. In some embodiments, the underlayer 56 can serve as a deposition guide for depositing a conversion material over a portion of the spacer layer 52. For patterning purposes, the conversion material fills portions of the previously removed patterned mandrel layer 136 to effectively restore those portions. Instead of being deposited via spin coating, the underlayer 56 is deposited via plasma-enhanced CVD, which provides better gap-filling capability than spin coating. The spacer layer 52 has alternating highs and lows, and the deposition process with excellent gap-filling capability provides a better base (improved morphology) for the subsequently deposited conversion material. Furthermore, instead of using a polymer as the material for the underlayer 56, the embodiments use amorphous carbon. Amorphous carbon can withstand higher temperatures than typical polymers, thus supporting a wider variety of films deposited thereon for conversion materials, intermediate layers, or overlayers. In addition, by using amorphous carbon, overlayer material layers can be deposited faster, with better material consistency, and at higher deposition temperatures to produce higher quality films.

[0034] In some embodiments, the CVD process for depositing amorphous carbon can be a plasma-enhanced process using a process temperature between 200°C and 400°C. Gaseous carbon such as C2H2, CH4, C3H62, etc.x H y The precursor (where x and y are mutually compatible indices) can be converted into a solid and deposited as amorphous carbon on spacer layer 52. The reaction used for depositing amorphous carbon can be characterized as follows:

[0035] Ar + +C x H y →Ar+C x H y + (Equation 1)

[0036] C x H y + +e→C x H (y-1) +H (Equation 2)

[0037] e+C x H (y-1) →C x H (y-1) + +2e (Equation 3)

[0038] Argon gas can be supplied to the deposition chamber using a radio frequency source, and a plasma of argon gas is generated from the deposition chamber. Hydrocarbon gases such as acetylene and methane are introduced into the deposition chamber. Argon ions interact with the hydrocarbon gases, thereby removing electrons from the hydrocarbon gases and creating hydrocarbon gas ions in Equation 1. Charged free electrons can interact with the hydrocarbon gas ions to remove hydrogen atoms from the hydrocarbon gas ions. The removal of hydrogen atoms from the hydrocarbon gas ions neutralizes the molecules, converting the hydrocarbon gas into a solid in Equation 2. Charged free electrons interact with the free-floating hydrocarbon solid, removing additional electrons from the hydrocarbon solid, thereby forming hydrocarbon solid ions in Equation 3. The hydrocarbon solid ions are attracted to the surfaces of spacer layer 52 and bottom layer 56 as they grow. The bottom layer 56 is grown to extend above spacer layer 52, and then the upper surface is planarized by an etch-back process, a planarization process such as chemical mechanical planarization (CMP), or a combination thereof.

[0039] The process temperature during deposition of the substrate 56 can be between approximately 200°C and 400°C. The stress characteristics of the substrate 56 can be between approximately 0 MPa and approximately -500 MPa. The hardness of the substrate 56 can be between approximately 10 GPa and 20 GPa, while the modulus can be between approximately 90 GPa and 110 GPa. The density of the substrate 56 can be between approximately 1 g / cm³. 3 and 1.5g / cm 3In some embodiments, the material composition of the bottom layer 56, as determined by Rutherford backscattering spectroscopy (RBS), may be between 78% and 80% carbon, between 19% and 21% hydrogen, and between 0.4% and 3% oxygen. In some embodiments, the material composition of the bottom layer 56 may be between 60% and 70% carbon, between 30% and 40% hydrogen, and between 1% and 5% oxygen (RBS).

[0040] exist Figure 8A and Figure 8B In the process, an intermediate layer 58 is deposited, followed by an upper layer 60. These layers can be formed using processes and materials similar to those discussed above with respect to intermediate layer 40 and upper layer 42. In some embodiments, intermediate layer 58 and / or upper layer 60 can be deposited using processes such as CVD instead of spin coating. Typically, CVD deposition processes can damage the underlying layer 56; however, because the underlying layer 56 is deposited using CVD and provides the film quality described above, this allows intermediate layer 58 to be deposited in a similar manner, and upper layer 60 to be deposited in a similar manner. Furthermore, the use of CVD provides that intermediate layer 58 (and / or upper layer 60) can be deposited in the same deposition chamber as the underlying layer 56, thereby reducing the processing time of workpiece 100. In some embodiments, upper layer 60 can be a metal oxide photoresist instead of an organic photoresist.

[0041] In some embodiments, alternative materials and processes for depositing the bottom layer 56, the intermediate layer 58, and the top layer 60 may be used to deposit the bottom layer 38, the intermediate layer 40, and the top layer 42 discussed above.

[0042] The thickness of the bottom layer is approximately 56. and Between. The thickness of the intermediate layer 58 can be approximately and Between. The thickness of the upper layer is 60. and Between. Although example ranges and thicknesses of the layers are provided, other thicknesses of these layers can be used.

[0043] Figure 9A and Figure 9B The diagram illustrates that after the formation of the upper layer 60, the upper layer 60 is patterned using an acceptable photolithography technique to form a patterned upper layer 160. The patterned upper layer 160 includes an opening 62 located therein.

[0044] exist Figure 10A and Figure 10B In the middle, the intermediate layer 58 is etched to form a patterned intermediate layer 158. A patterned upper layer 160 is then used. Figure 9A and Figure 9BThe intermediate layer 58 is etched using an etching mask, such that the pattern of the patterned upper layer 160 is transferred to the intermediate layer 58 to create a patterned intermediate layer 158. During the patterning of the intermediate layer 158, the patterned upper layer 160 may be partially or completely consumed. Etching the intermediate layer 58 causes an opening 64 in the patterned intermediate layer 158 to extend from the opening 62. Any suitable etching technique can be used, such as wet etching or dry etching using an etchant selective to the material of the intermediate layer 158.

[0045] Figure 11A , Figure 11B , Figure 12A and Figure 12B The process of omitting intermediate layer 58 according to some embodiments is shown. Figure 11A and Figure 11B In this configuration, the upper layer 60 is formed directly on the lower layer 56. Because the lower layer 56 is formed of amorphous carbon, organic photoresists (such as those found in the upper layer 42) can be used while still maintaining good etch selectivity between the upper layer 60 and the lower layer 56. In some embodiments, a metal oxide photoresist can be used instead of the upper layer 60, which allows for even better etch selectivity without requiring an intermediate layer 58. The upper layer 60 (including organic photoresists or metal oxide photoresists) can be deposited using a spin coating process or a CVD deposition process. Typically, CVD processes damage the lower layer 56; however, because the lower layer 56 is deposited via a CVD process and possesses the aforementioned film properties, it can withstand higher temperature deposition processes.

[0046] Figure 12A and Figure 12B The diagram illustrates that after the formation of the upper layer 60, the upper layer 60 is patterned using an acceptable photolithography technique to form a patterned upper layer 160. The patterned upper layer 160 includes openings 64 that expose portions of the lower layer 56.

[0047] exist Figure 13A and Figure 13B In the middle, the bottom layer 56 is then etched to form a patterned bottom layer 156, which can also be referred to as bottom layer 156. The intermediate layer 158 is used as an etching mask to etch the bottom layer 56. Figure 10A and Figure 10B ) or upper 160 ( Figure 12A and Figure 12B This allows the pattern of the intermediate layer 158 (or upper layer 160) to be transferred to the bottom layer 56 to create a patterned bottom layer 156. The bottom layer 156 has openings 64 ( Figure 10A or Figure 12AAn extended opening 66. If the patterned upper layer 160 is not completely consumed during the patterning of the intermediate layer 158, the patterned upper layer 160 will be completely consumed during the patterning of the bottom layer 156. In process variations, the opening 66 may be tapered or may have vertical sidewalls. Any suitable etching technique may be used, such as wet etching or dry etching using an etchant selective for the material of the bottom layer 156. For example, in some embodiments, the etchant may be an O2-based or N2 / H2-based etchant gas used in an etching chamber with other process gases. After etching the patterned bottom layer 156, the patterned intermediate layer 158 (if used) and upper layer 160 (if still present) may be removed by a suitable process.

[0048] exist Figure 14A and Figure 14B In this process, a conversion material 68 can be deposited in the opening 66. Therefore, the patterned underlayer 156 serves as the underlayer of the photomask and a template for depositing the conversion material 68. The conversion material 68 is used to modify the effect of a previous etching. For example, a pattern can be etched at a specific spacing due to a pattern loading effect; however, the pattern can then be altered by using the conversion material 68. In various embodiments, the conversion material 68 comprises an inorganic material. For example, the conversion material 68 can be an inorganic oxide, such as titanium oxide, tantalum oxide, silicon oxide, etc. Because the underlayer 156 is amorphous carbon deposited by CVD, the conversion material 68 does not need to be a low-temperature oxide (i.e., an oxide deposited using a low-temperature process of about 200°C or lower). Instead, the conversion material 68 includes a wider range of candidate materials. In some embodiments, the conversion material 68 may include nitrides, such as silicon nitride or silicon oxynitride, etc. The conversion material 68 can be selected to have sufficient etch selectivity for the spacer layer 52 relative to the same etch process. For example, in some embodiments, the ratio of the etch rate of the conversion material 68 to the etch rate of the spacer layer 52 relative to the same etch process is at least 0.7.

[0049] The conversion material 68 can be formed using semiconductor film deposition processes such as CVD, PVD, ALD, etc. In some embodiments, the conversion material 68 can be deposited at a process temperature between 50°C and about 300°C (e.g., between 200°C and 300°C). The process temperature can be, for example, higher than the temperature for depositing low-temperature oxides, because the underlying layer 156 is CVD-deposited amorphous carbon, which can withstand higher temperatures than spin-coated polymers. The semiconductor film deposition process can be a conformal process, in which a semiconductor film is formed on the sidewalls and bottom surface of the opening 66 (see...). Figure 12A and Figure 12BAs deposition continues, portions of the transition material 68 on the opposite sidewalls of opening 66 (which fill opening 66) may merge. As a result of the semiconductor film deposition process, the top surface of the transition material 68 may not be planar.

[0050] exist Figure 15A and Figure 15B In this process, the conversion material 68 can then be trimmed in an etch-back process, a planarization process, or a combination thereof. A planarization process (e.g., chemical mechanical planarization (CMP), dry etching, a combination thereof, etc.) can be performed to remove excess portions of the conversion material 68 outside the opening 66. After the planarization process, the underlying layer 156 is exposed, and the top surfaces of the conversion material 68 and the underlying layer 156 can be planar and coplanar. In some embodiments, the planarization process can also remove pits formed in the upper surface of the conversion material 68.

[0051] exist Figure 16A and Figure 16B Next, an ashing or etching process is used to remove the underlying layer 156. After removing the underlying layer 156, the pillars of the conversion material 68 remain. The remaining conversion material 68 masks a selected area of ​​the spacer layer 52. In some embodiments, the conversion material 68 can extend from a first sidewall portion of the spacer layer 52 located on a first mandrel 136 to a second sidewall portion of the spacer layer 52 located on a second corresponding mandrel 136.

[0052] exist Figure 17A and Figure 17B In order to achieve the desired profile, the conversion material 68 can then be trimmed in the etch-back process. In some embodiments, the conversion material 68 is trimmed so that it lies below the uppermost surface of the spacer layer 52, for example, below the top surface of the mandrel 136, thereby forming a conversion material 168. The trimmed conversion material 168 may expose a portion of the spacer layer 52 above the mandrel 136. In some embodiments, the trimmed conversion material 68 may also reduce the width of the conversion material 68.

[0053] Trimming the conversion material 68 may include a dry etching process or a combination of dry and wet etching processes. Embodiments of a dry etching process for trimming the conversion material 68 may include the use of a fluorocarbon-based etchant (e.g., CF4). Other process gases may be used in combination with the fluorocarbon-based etchant, such as oxygen (O2), nitrogen (N2), argon (Ar), combinations thereof, etc. Embodiments of a wet etching process for trimming the conversion material 68 may include the use of diluted hydrofluoric acid as an etchant. For example, the desired shape of the conversion material 168 can be achieved by controlling the concentration and duration of the trimming process.

[0054] In some embodiments, trimming the conversion material 168 can be performed by anisotropic etching, which also etches the spacer layer 52 to remove the horizontal portions of the spacer layer 52 exposed by the conversion material 68. Figure 17A and Figure 17B As shown, the horizontal portion of the spacer layer 52 beneath the transition material 68 is not removed. This process results in a self-aligned spacer mask 152, which includes a separate vertical portion of the spacer layer 52 and a portion of the spacer layer 52 spanning the mandrel of the patterned mandrel layer 136. Opening 70A exposes a portion of the mask layer 34. Opening 70B represents a recess in the transition material 168.

[0055] exist Figure 18A and Figure 18B In this process, selected mandrels in the patterned and mandrel layers 136 can be removed to form further openings between the vertical spacers of the spacer mask 152. Three-layer or two-layer lithography processes can be used to remove the selected mandrels. A base layer 72 can be deposited over the spacer mask 152, the patterned mandrel layer 136, and the transition material 168. In some embodiments, the base layer 72 can be formed using processes and materials similar to those used to form the base layer 38. In other embodiments, the base layer 72 can be formed using processes and materials similar to those used to form the base layer 56. In some embodiments, an intermediate layer 74 (if used) can be deposited over the base layer 72 using materials and processes similar to those used to form the intermediate layer 40, while in other embodiments, an intermediate layer 74 can be formed using processes and materials similar to those used to form the intermediate layer 58. In some embodiments, an upper layer 76 can be deposited over the intermediate layer 74 (if used) or the base layer 72 using materials and processes similar to those used to form the upper layer 42, while in other embodiments, an upper layer 76 can be formed using processes and materials similar to those used to form the upper layer 60.

[0056] exist Figure 19A and Figure 19B In this process, after the upper layer 76 is formed, the upper layer 76 is patterned using an acceptable photolithography technique to form a patterned upper layer 176, for example, by exposing the upper layer 76 to light through a photomask and developing the upper layer 76 to remove portions thereof. The patterned upper layer 176 includes an opening 78 located therein.

[0057] exist Figure 20A and Figure 20BIn this process, using processes such as those discussed above regarding intermediate layer 40 or intermediate layer 58, intermediate layer 74 (if used) is etched to form a patterned intermediate layer. Substrate 72 is then etched to form a patterned substrate 172. Substrate 72 is etched using patterned intermediate layer 174 (if used) as an etching mask or using patterned upper layer 176 as an etching mask, such that the pattern of intermediate layer 174 (or upper layer 176) is transferred to substrate 72 to create patterned substrate 172. Substrate 138 has an opening 84. In process variations, opening 84 may be tapered or may have vertical sidewalls. Any suitable etching technique may be used, such as wet etching or dry etching using an etchant selective for the material of substrate 72. For example, in some embodiments, the etchant may be an O2-based or N2 / H2-based etchant gas used in an etching chamber with other process gases.

[0058] exist Figure 21A and Figure 21B In the etching step, the patterned mandrel layer 136 is selectively etched to remove the exposed mandrel, thereby forming an opening 84 in the patterned mandrel layer 136. According to some embodiments, etching is performed using wet etching or dry etching. The appropriate etchant may include an HF solution or a mixture of NF3 and NH3 gases, and a suitable etchant depends on the material of the patterned mandrel layer 136.

[0059] exist Figure 22A and Figure 22B In the process, for example, the underlying layer 172 is removed by a suitable ashing or etching process. Therefore, openings of various types / widths can be formed in the initial mandrel layer 36. The structure constituting the patterned mask covering the mask layer 34 may include portions of the patterned mandrel layer 236, spacer mask 152, and portions of the transformation material 168. Together, they are designated as composite mask 86. (As mentioned above regarding...) Figure 17A and Figure 17B As described, the transformation material 168 specifically covers portions of the spacer mask 152 to protect those horizontal portions of the spacer mask 152 that should not be removed.

[0060] exist Figure 23A and Figure 23BIn this process, a composite mask 86 is used as an etching mask to etch mask layer 34, thereby transferring the pattern of composite mask 86 to mask layer 34 to create patterned mask layer 134, which may also be referred to as mask layer 134. Patterned mask layer 134 has an opening 88 extending from opening 70A and opening 84. Etching of patterned mask layer 134 can be performed by any suitable technique selective for the material of mask 34, such as by wet etching or dry etching. In some embodiments, etching of patterned mask layer 134 may consume part or all of composite mask 86, such as the transformation material 168 from composite mask 86. Reference Figure 23A and Figure 23B Because the transition material 168 and the dielectric layer 34 can have similar etch selectivity, the transition material 168 is removed while the dielectric layer 34 is being etched. The patterned mandrel layer 236 is not shown as being removed because it has high etch selectivity for the dielectric layer 34. The spacer mask 152 can be removed or can be retained wholly or partially, depending on the etch selectivity of the spacer mask 152 for the dielectric layer 34. In embodiments where the spacer mask 152 is removed while the dielectric layer 34 is being etched, the transition material 168 serves to protect portions of the dielectric layer 34 beneath the transition material 168 from being etched. For example, the spacer mask 152 located directly beneath the transition material 168 may be accidentally etched during the etching of the dielectric layer 34. The mask layer 32 serves as an etch stop for the etching of the dielectric layer 34.

[0061] exist Figure 24A and Figure 24B In the process, after etching the patterned mask layer 134, the patterned mask layer 134 is used to pattern the mask 32 to form the patterned mask layer 132 by using the patterned mask layer 134 as an etching mask, such that the pattern of the mask layer 134 is transferred to the mask 32. The etchant and etching technique used can be selective for the material of the patterned mask layer 132.

[0062] The patterned mask layer 132 serves as an etch mask to progressively transfer the pattern of the patterned mask layer 132 to the underlying mask 30 to form the patterned mask 130, to the target layer 28 to form the patterned target layer 128, and to the ESL 26 to form the patterned etch stop layer 126, by sequentially etching each layer using one or more previous layers as masks. In some embodiments, the remaining portion of the patterned mask layer 134 can be removed by a separate process before using the patterned mask layer 132 as a mask for etching the underlying layer. In some embodiments, the remaining portion of the patterned mask layer 134 can be removed simultaneously with the etch mask 30.

[0063] The patterned target layer 128 and the patterned etch stop layer 126 can be etched using suitable etching techniques, such as wet etching or dry etching using a suitable etchant selective to the corresponding material to be etched. Specifically, the patterned target layer 128 can be etched using plasma or RIE anisotropic etching with ESL 26 as the etch stop, such that the width of the resulting trench is relatively uniform throughout the process. Then, in subsequent processes, the patterned target layer 128, the patterned mask 130, or the patterned mask layer 132 can be used as a mask to etch the ESL 26 to expose the component 24. Openings 90 formed in the patterned target layer 128 can include trenches and / or vias. For example, vias can reach the exposed conductive component 24, while trenches can be formed with a bottom located between the topmost surface and the bottommost surface of the patterned target layer 128.

[0064] exist Figure 25A and Figure 25B In this process, conductive filler 96 is deposited in openings 90 of a patterned target layer 128. Prior to depositing the conductive filler 96, a pad 92 may be deposited in the openings 90. The pad 92 may include a diffusion barrier layer, an adhesion layer, and / or the like. The pad 92 may be formed of titanium, titanium nitride, tantalum, tantalum nitride, or other alternatives. A seed layer 94 may be formed over the pad 92 and may include a conductive material such as copper, copper alloy, silver, gold, tungsten, aluminum, etc. According to some embodiments, forming the pad 92 includes performing ALD or CVD deposition, and forming the seed layer 94 may include performing PVD, ALD, or CVD deposition. The conductive filler 96 may be deposited in the remaining portion of the openings 90 and may include any suitable conductive material such as copper, copper alloy, silver, gold, tungsten, aluminum, cobalt, etc. The conductive filler 96 may be deposited by any suitable process, such as electroplating, electroless plating, CVD, sputtering, etc.

[0065] exist Figure 26A and Figure 26B In this process, planarization, such as chemical mechanical planarization (CMP), is performed to smooth the surface of the conductive filler 96 and (e.g., from the pad 92 and / or seed layer 94) remove excess conductive material. In some embodiments, the pad 92, seed layer 94, and conductive filler 96 can be deposited while the patterned mask 130 is still in place. In such embodiments, the patterned mask 130 can be removed during planarization or etched after planarization. The planarization process can separate the conductive filler 96 into individual contacts 98.

[0066] exist Figure 27A and Figure 27BIn this process, after planarization, a capping layer 99 is formed over the contact 98. The capping layer 99 can be deposited over the contact 98, pad 92, seed layer 94, and patterned target layer 128. The capping layer 99 may include cobalt, ruthenium, or combinations thereof. The capping layer 99 provides protection against oxidation of the underlying portion of the contact 98 (such as conductive filler 96). The deposition of the capping layer 99 may use conductive filler 96 as a seed layer in some deposition processes. After depositing the material of the capping layer 99, in some embodiments, excess portions may optionally be removed using any suitable method, such as using a suitable photolithography process. For example, photoresist may be formed on the material of the capping layer 99 and patterned to expose portions of the capping layer 99 that are not directly above the contact 98. The exposed portions can then be removed by etching or any suitable method, and the photoresist can then be removed by any suitable method. In some embodiments, the capping layer 99 is selectively deposited over the conductive filler 96 or over one or more of the conductive filler 96, seed layer 94, or pad 92, for example, by using a conductive filler 96, a seed layer 94, or a pad 92 as a seed layer in some deposition processes. In some embodiments, excess portions of the capping layer 99 can be removed by a cleaning process that removes portions of the capping layer 99 deposited on the patterned target layer 128 that are not well bonded thereto. The capping layer 99 can be deposited using CVD, PECVD, PVD, ALD, PEALD, ECP (such as high-voltage ECP), or chemical plating, etc. The capping layer 99 may have approximately Peace Treaty The thickness between.

[0067] In subsequent steps, an additional etch stop layer (not shown) can be formed, and further low-k dielectric layers, metal lines, and vias (not shown) can be formed above the additional etch stop layer. The process steps and the resulting structure can be similar to... Figure 1A and Figures 1B to 27A and Figure 27B The structure shown.

[0068] The embodiments achieve several advantages. Using an amorphous carbon chemical vapor deposition (CVD) underlayer allows for the deposition of the overlayer to produce higher quality films by allowing for increased deposition process temperatures typically achievable. Topography issues are resolved, and the overlayer can be deposited in a manner that reduces potential defects or photomask alignment errors. Furthermore, the embodiments allow for the use of two-layer or three-layer photomask structures. In the case of a three-layer photomask structure, the intermediate layer can be deposited via a CVD process due to the high-temperature tolerance and flexibility provided by the underlayer. In the case of a two-layer photomask, the upper layer can be a metal oxide photoresist. The underlayer can then be used as a template for depositing a transition material on the spacer layer to control the patterning design.

[0069] One embodiment is a patterning method comprising forming a spacer layer over a patterned mandrel layer. The method further comprises forming an insulating layer over the spacer layer, the insulating layer comprising amorphous carbon. The method further comprises patterning the insulating layer to form openings in the insulating layer that expose portions of the spacer layer disposed between two mandrels of the patterned mandrel layer. The method further comprises depositing a conversion material in the openings. The method further comprises removing the insulating layer, the conversion material, and the exposed horizontal portions of the spacer layer, wherein portions of the conversion material retain portions of the spacer layer covering the two mandrels of the patterned mandrel layer. The method further comprises removing one or more mandrels from the patterned mandrel layer. The method further comprises etching a target layer based on a pattern determined by the combination of the patterned mandrel layer, the spacer layer, and the conversion material. In one embodiment, depositing the conversion material comprises heating the insulating layer to a temperature between 200°C and 300°C. In one embodiment, forming the insulating layer comprises using a chemical vapor deposition process with a hydrocarbon gas as a precursor. In one embodiment, the insulating layer has an oxygen content of less than 5%. In one embodiment, etching the target layer forms a second opening in the target layer, the second opening exposing a conductive component beneath the target layer. The method further includes: depositing a pad layer; depositing a conductive filler; planarizing the conductive filler to separate the conductive filler into first contacts; and covering the first contacts with a metal capping layer. In one embodiment, the metal capping layer comprises cobalt. In one embodiment, the method further includes: depositing a first patterned layer over an insulating layer, the first patterned layer comprising photoresist, and developing the photoresist to form a first pattern in the first patterned layer. The first pattern is transferred to the patterned insulating layer. In one embodiment, the method further includes: depositing a second patterned layer over the insulating layer, the second patterned layer being interposed between the first patterned layer and the insulating layer, the second patterned layer comprising an inorganic material. In one embodiment, the photoresist of the first patterned layer comprises a metal oxide.

[0070] Another embodiment is a patterning method comprising depositing a conformal spacer layer over a mandrel assembly. The method further comprises depositing an underlayer of a photomask over the spacer layer, the underlayer comprising carbon, hydrogen, and oxygen, having less than 5% oxygen. The method further comprises depositing an upper layer of the photomask over the underlayer, the upper layer comprising photosensitive photoresist. The method further comprises developing the upper layer to form a first pattern in the upper layer. The method further comprises transferring the first pattern to the underlayer, the first pattern exposing a first portion of the spacer layer. The method further comprises depositing a protective layer over the underlayer and over the first portion of the spacer layer. The method further comprises removing the underlayer to expose the spacer layer except for the first portion of the spacer layer located beneath the protective layer. The method further comprises etching the spacer layer to remove horizontal portions of the spacer layer except for the first portion of the spacer layer located beneath the protective layer. The method further comprises etching the mandrel assembly to remove one or more mandrels. The method further comprises etching a target layer located beneath the spacer layer to form a second pattern in the target layer, the second pattern being based on using the remaining spacer layer including the first portion of the spacer layer as an etch mask. In one embodiment, depositing the underlayer includes: supplying a plasma gas to the deposition chamber; supplying a hydrocarbon precursor gas to the deposition chamber; and controlling the reaction between the plasma gas and the hydrocarbon precursor gas to deposit the underlayer. In one embodiment, a protective layer is deposited at a process temperature between 200°C and 300°C. In one embodiment, the upper layer of the photomask comprises a metal oxide photoresist. In one embodiment, the method further includes: depositing an intermediate layer of the photomask above the underlayer before depositing the upper layer. In one embodiment, the intermediate layer is deposited using a chemical vapor deposition process.

[0071] Another embodiment is a patterning method including depositing a bottom mask layer over a target layer using a hydrocarbon precursor. The method further includes depositing a top mask layer over the bottom mask layer. The method further includes patterning the top mask layer using a photolithography process to form a patterned top mask. The method further includes etching a bottom mask layer based on the patterned top mask to form a patterned bottom mask, the patterned bottom mask including a first opening. The method further includes depositing a conversion material in the first opening. The method further includes removing the bottom mask layer and thinning the conversion material, a first portion of which is disposed on a spacer layer between two mandrels of the mandrel layer. The method further includes etching the spacer layer to remove horizontal portions of the spacer layer other than those below the first portion of the conversion material. The method further includes transferring a pattern of the remaining spacer layer, remaining mandrel layer, and remaining conversion material to the mask layer. The method further includes etching the target layer based on the pattern of the mask layer. In one embodiment, the method further includes depositing an intermediate mask layer inserted between the top and bottom mask layers. In one embodiment, a conversion material extends above the upper surface of the bottom mask layer, wherein depositing the conversion material includes heating the bottom mask layer to a temperature between 200°C and 300°C. In one embodiment, a hydrocarbon precursor interacts with argon ions to form the bottom mask layer via a chemical vapor deposition process, the bottom mask layer comprising amorphous carbon. In one embodiment, the top mask layer comprises a metal oxide photoresist.

[0072] The foregoing outlines features of several embodiments to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art will understand that they can readily use this disclosure as a basis for designing or modifying other processes and structures to achieve the same purposes and / or advantages of the embodiments described herein. Those skilled in the art will also recognize that such equivalent structures do not depart from the spirit and scope of the invention, and that various changes, substitutions, and modifications can be made within the invention without departing from its spirit and scope.

Claims

1. A method for patterning, comprising: A spacer layer is formed above the patterned mandrel layer; An insulating layer is formed over the spacer layer, the insulating layer comprising amorphous carbon; The insulating layer is patterned to form an opening in the insulating layer, the opening exposing a portion of the spacer layer disposed between two mandrels of the patterned mandrel layer; Deposit the transformation material in the opening; Remove the insulating layer, the transition material, and the exposed horizontal portion of the spacer layer, wherein a portion of the transition material remains covering a portion of the spacer layer between the two mandrels of the patterned mandrel layer; Remove one or more mandrels from the patterned mandrel layer; The target layer is etched based on a pattern determined by the combination of the patterned mandrel layer, the spacer layer, and the transition material, wherein the etched target layer forms a second opening in the target layer, the second opening exposing conductive components beneath the target layer; Deposited liner layer; Deposited conductive filler; Planarize the conductive filler to separate the conductive filler into first contacts; and The first contact is covered with a metal overlay.

2. The method according to claim 1, wherein, Depositing the transformation material involves heating the insulating layer to a temperature between 200°C and 300°C.

3. The method according to claim 1, wherein, Forming the insulating layer includes using a chemical vapor deposition process with hydrocarbon gases as precursors.

4. The method according to claim 1, wherein, The insulating layer has an oxygen content of less than 5%.

5. The method according to claim 1, wherein, The transformation material is an inorganic oxide.

6. The method according to claim 1, wherein, The metal coating includes cobalt.

7. The method according to claim 1, further comprising: A first patterned layer is deposited over the insulating layer, the first patterned layer comprising photoresist, and the photoresist is developed to form a first pattern in the first patterned layer; as well as In the patterning of the insulating layer, the first pattern is transferred to the insulating layer.

8. The method according to claim 7, further comprising: A second patterned layer is deposited over the insulating layer, the second patterned layer being inserted between the first patterned layer and the insulating layer, the second patterned layer comprising an inorganic material.

9. The method according to claim 7, wherein, The photoresist of the first patterned layer comprises a metal oxide.

10. A method for patterning, comprising: A conformal spacer layer is deposited above the mandrel assembly; A photomask underlayer is deposited above the spacer layer, the photomask underlayer comprising carbon, hydrogen and oxygen, the underlayer having less than 5% oxygen; An upper layer of the photomask is deposited over the bottom layer, the upper layer comprising photosensitive photoresist; Develop the upper layer to form a first pattern in the upper layer; The first pattern is transferred to the bottom layer, whereby the first pattern exposes a first portion of the spacer layer; A protective layer is deposited over the bottom layer and over the first portion of the spacer layer; Remove the underlying layer to expose the spacer layer except for the first portion of the spacer layer located beneath the protective layer; The spacer layer is etched to remove the horizontal portion of the spacer layer except for the first portion located beneath the protective layer; Etching one or more mandrels in the mandrel group to remove one or more mandrels, wherein at least a first mandrel in the mandrel group is retained after etching the one or more mandrels; as well as After etching one or more mandrels, a target layer located below the spacer layer is etched to form a second pattern in the target layer, the second pattern being based on the first mandrel and the remaining spacer layer including the first portion of the spacer layer as an etching mask.

11. The method according to claim 10, wherein, The deposited substrate includes: Supply plasma gas to the deposition chamber; Hydrocarbon precursor gas is supplied to the deposition chamber; and The reaction between the plasma gas and the hydrocarbon precursor gas is controlled to deposit the underlying layer.

12. The method according to claim 10, wherein, The protective layer is deposited at a process temperature between 200°C and 300°C.

13. The method according to claim 10, wherein, The upper layer of the photomask comprises a metal oxide photoresist.

14. The method of claim 10, further comprising: Before depositing the upper layer, an intermediate layer of the photomask is deposited over the lower layer.

15. The method according to claim 14, wherein, The intermediate layer is deposited using a chemical vapor deposition process.

16. A method for patterning, comprising: A core layer is formed above the target layer; A spacer layer is formed above the mandrel layer; A bottom mask layer is deposited above the spacer layer using a hydrocarbon precursor; A top mask layer is deposited above the bottom mask layer; The top mask layer is patterned using a photolithography process to form a patterned top mask; The bottom mask layer is etched based on the patterned top mask to form a patterned bottom mask, the patterned bottom mask including a first opening; Deposit the transformation material in the first opening; Remove the bottom mask layer and thin the transition material, a first portion of which is disposed on the spacer layer between the two mandrels of the mandrel layer; Etch the spacer layer to remove the horizontal portion of the spacer layer except for the horizontal portion of the spacer layer below the first portion of the conversion material; The patterns of the remaining spacer layer, the remaining mandrel layer, and the remaining conversion material are transferred to the mask layer; as well as The target layer is etched based on the pattern of the mask layer.

17. The method of claim 16, further comprising depositing an intermediate mask layer inserted between the top mask layer and the bottom mask layer.

18. The method according to claim 16, wherein, The transformation material extends above the upper surface of the bottom mask layer, wherein depositing the transformation material includes heating the bottom mask layer to a temperature between 200°C and 300°C.

19. The method of claim 16, wherein, The hydrocarbon precursor interacts with argon ions to form the bottom mask layer via a chemical vapor deposition process, the bottom mask layer comprising amorphous carbon.

20. The method of claim 16, wherein, The top mask layer comprises metal oxide photoresist.

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