Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
  • H01L21/033—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers
  • H01L21/0334—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
  • H01L21/0337—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising inorganic layers characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/0002—Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/027—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34
  • H01L21/0271—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers
  • H01L21/0273—Making masks on semiconductor bodies for further photolithographic processing not provided for in group H01L21/18 or H01L21/34 comprising organic layers characterised by the treatment of photoresist layers
  • H01L21/0274—Photolithographic processes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
  • H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
  • H01L21/3081—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their composition, e.g. multilayer masks, materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
  • H01L21/308—Chemical or electrical treatment, e.g. electrolytic etching using masks
  • H01L21/3083—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane
  • H01L21/3086—Chemical or electrical treatment, e.g. electrolytic etching using masks characterised by their size, orientation, disposition, behaviour, shape, in horizontal or vertical plane characterised by the process involved to create the mask, e.g. lift-off masks, sidewalls, or to modify the mask, e.g. pre-treatment, post-treatment
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
  • H01L21/3105—After-treatment
  • H01L21/31051—Planarisation of the insulating layers
  • H01L21/31053—Planarisation of the insulating layers involving a dielectric removal step
  • H01L21/31055—Planarisation of the insulating layers involving a dielectric removal step the removal being a chemical etching step, e.g. dry etching
  • H01L21/31056—Planarisation of the insulating layers involving a dielectric removal step the removal being a chemical etching step, e.g. dry etching the removal being a selective chemical etching step, e.g. selective dry etching through a mask
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/31—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to form insulating layers thereon, e.g. for masking or by using photolithographic techniques; After treatment of these layers; Selection of materials for these layers
  • H01L21/3105—After-treatment
  • H01L21/311—Etching the insulating layers by chemical or physical means
  • H01L21/31144—Etching the insulating layers by chemical or physical means using masks

Definitions

• This disclosure relates to substrate processing, and, more particularly, to techniques for patterning substrates including patterning semiconductor wafers.
• creating patterned layers comprises the application of a thin layer of radiation- sensitive material, such as photoresist, to an upper surface of a substrate.
• This radiation-sensitive material is transformed into a relief pattern which can be used as an etch mask to transfer a pattern into an underlying layer on a substrate.
• Patterning of the radiation-sensitive material generally involves exposure to actinic radiation through a reticle (and associated optics) onto the radiation-sensitive material using, for example, a photo-lithography system. This exposure can then be followed by the removal of irradiated regions of the radiation-sensitive material (as in the case of positive photoresist), or non-irradiated regions (as in the case of negative resist) using a developing solvent.
• This mask layer can comprise multiple sub-layers.
• Pitch reduction techniques are termed (often somewhat erroneously yet routinely) "pitch multiplication” as exemplified by "pitch doubling" et cetera.
• Pitch reduction techniques can extend the capabilities of photolithography beyond feature size limitations (optical resolution limitations). That is, conventional multiplication of pitch (more accurately pitch reduction, or multiplication of pitch density) by a certain factor involves reducing a target pitch by a specified factor. Double patterning techniques used with 193 nm immersion lithography are conventionally considered as one of the most promising techniques to pattern 22 nm nodes and smaller.
• SADP self-aligned spacer double patterning
• Techniques disclosed herein provide a method for pitch reduction (increasing pitch/feature density) for creating high-resolution features and also for cutting on pitch of sub-resolution features.
• Techniques herein include positioning multiple lines of materials (multiple adjacent materials) having different etch characteristics on a substrate. Then an etch mask is formed on the multiple lines of materials to isolate a portion of those materials to selectively etch features and create cuts and blocks where desired.
• the multiple materials can be a pattern of alternating, sub-resolution lines, and each line can be preferentially etched relative to the other lines.
• the etch mask combined with one or more etched lines, provides a combined etch mask defining sub-resolution features.
• methods herein provide a sequence of materials that provide selective self-alignment, such as for blocking or cutting. Combined with an underlying transfer layer or memorization layer, many different etch seiectivities can be accessed.
• One embodiment includes a method of patterning a substrate.
• a multiline layer is formed above or on an underlying layer.
• the multi-line layer includes a region having a pattern of alternating lines of two or more differing materials. Each line has a horizontal thickness, a vertical height, and extends across the underlying layer. Each line of the pattern of alternating lines is uncovered on a top surface of the multi-line layer and vertically extends to a bottom surface of the multi-line layer. At least two of the two or more differing materials differ chemically from each other by having different etch resistivities relative to each other.
• a patterned mask layer is formed on the multi-line layer.
• the patterned mask layer includes mask material that masks a portion of the multi-line layer. At least one of the two or more differing materials are selectively removed resulting in a portion of the underlying layer being uncovered.
• FIGS. 1A, B, 1 C, and 1 D are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 2A and 2B are top views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 3A and 3B are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 4A and 4B are top views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 5A and 5B are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 6A and 8B are top views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 7A and 7B are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 8A and 8B are top views of an example substrate segment according to embodiments disclosed herein.
• FIGS, 9A and 9B are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• FIGS. 10A and 10B are top views of an example substrate segment according to embodiments disclosed herein.
• FIGS, 1 1-18 are cross-sectional side views of an example substrate segment according to embodiments disclosed herein.
• Techniques disclosed herein provide a method and fabrication structure for pitch reduction (increasing pitch/feature density) for creating high- resolution features and also for cutting on pitch of sub-resolution features.
• Techniques include using multiple materials having different etch characteristics to selectively etch features and create cuts or blocks where specified.
• a pattern of alternating materials is formed on an underlying layer.
• An etch mask is positioned on the pattern of alternating materials.
• One or more of the alternating materials can be preferentially removed relative to other materials to uncover a portion of the underlying layer.
• the etch mask and the remaining lines of alternating material together form a combined etch mask defining sub-resolution features.
• Various patterns of materials can be formed on the underlying layer, and patterns can include two, three, four, five, or more different materials. Patterns can include having half pitches below 40 nanometers and even below 12 nanometers and smaller. Critical dimensions of materials can be controlled by type of deposition (such as with atomic layer deposition) instead of relying only on optical resolution of lithography systems.
• One embodiment includes a method of patterning a substrate. Such a method is useful for microfabrication of semiconductor devices and integrated circuits.
• a multi-line layer is formed above or on underlying layer 135.
• the multi-line layer can be formed directly on the underlying layer, or on any intervening layer or interfaciai films or
• the multi-line layer includes a region having a pattern of alternating lines of two or more differing materials.
• the alternating lines can cover essentially an entire surface of a substrate, but in other alternative embodiments only particular regions have the pattern of alternating lines.
• Each line has a horizontal thickness, a vertical height, and extends across the underlying layer.
• the alternating lines can include straight lines, curved lines, race track path, et cetera.
• Another example of alternating lines is a set of concentric circles with each ring being a curved line.
• Each line of the pattern of alternating lines is uncovered on a top surface of the multiline layer and vertically extends to a bottom surface of the multi-line layer, in other words, each line of a particular material can be anisotropicaliy etched to a bottom surface of the multi-line layer thereby uncovering underlying layers because lines of material alternate horizontally across a substrate surface in contrast to a vertical stack of materials. At least two of the two or more differing materials differ chemically from each other by having different etch resistivities relative to each other.
• etch resistivities from each other means that there is at least one etchant (or etchant combination) that etches a given one material at a greater rate than the other materiai(s). Note that there can exist particular etchants that etch two or more given materials at a same rate, but there is at least one etchant that etches an included material faster relative to the other material(s). Etching one material relative to another can include etching one material without substantially etching the other, or etching one material at a substantially greater rate as compared to the other material such as having an etch rate ratio of 3: 1 , 4: 1 , 10: 1 , etc.
• FIGS. 1A, 1 B, 1 C, and 1 D illustrate example results of forming a particular multi-line layer.
• FIGS. A and 1 B show a side cross- sectional substrate segment having three lines of material formed thereon. The different materials are labeled A, B, and C.
• bracket 151 shows a particular pattern segment of alternating lines. This pattern follows a sequence of A-B-C-B, which is then repeated. Thus, this pattern can continue with the sequence of A-B-C- B-A-B-C-B-A-B-C-B-A and so on.
• material A can be isolated from being in contact with material C by having lines of material B on both sides of material A.
• the half pitch of a given material can be varied so that material C can be absent in some regions or larger in other regions.
• FIGS. 2A and 2B show a top view of this substrate segment. Note that from a top view each different material from the multi-line layer 150 is uncovered or accessible,
• FIG. 1C shows multi-line layer 150 having a different pattern of alternating lines in that there are just two materials (A and B) that alternate with each other as shown by bracket 152.
• FIG. 1 D shows multi-line layer 150 having a different pattern of alternating lines with four materials.
• Bracket 153 marks a segment of this example pattern that can be repeated.
• an alternating pattern of repeating lines can having sequence of A-B-C-D-C-B-A-B-C-D-C-B-A, which can continue as is or have some areas with pitch variation.
• an etch mask can be used to isolate particular regions of the multi-line layer for selective removal of one or more of these materials to modify a combined etch mask (either adding to the etch mask or subtracting from the etch mask as an aggregate etch mask) as will be subsequently described.
• the patterned mask layer includes mask material
• patterned mask layer 140 can be lithographically patterned, or can be the result of a given pitch multiplication process.
• the mask material 41 can include organic materials and photoresists, inorganic materials as well as metal- containing materials, organometal!ic, et cetera.
• a mask layer material is deposited on multi-line layer 150, such as by spin-on deposition, chemical vapor deposition, etc. The mask material is then patterned and etched to remove a portion of the mask material, thereby resulting in a relief pattern of mask material on substrate 105.
• FIG, 3A is a side cross-sectional view through a center portion of FIG. 4A.
• FIGS. 3B and 4B show a different
• patterned mask layer 140 in which mask material 141 is a mesa defining an opening, that is, the area surrounding the mesa is the opening.
• Both types of relief patterns are shown in the drawings to illustrate different resulting patterns that come from different arrangement of materials, as will be apparent below.
• the patterned mask layer 140 can include multiple individual mask layers including separately patterned layers. For example, a few litho-etch operations can be executed during mask layer formation.
• the mask layer itself can include multiple mask patterns or films, or can be created as a result of decomposition pattern forming techniques.
• FIG. 5A shows an example of such selective removal.
• material B has been removed through openings in the patterned mask layer 140, such as by directional etching.
• Materials C and A remain as part of the patterned mask layer 140.
• FIG. 6A from a top view, portions of the underlying layer 135 are uncovered. Note that in FIG. 6A, the opening in patterned mask layer 140 is narrowed or restricted by lines of materials A and C, leaving two relatively smaller openings when the multi-line layer 150 is combined with the patterned mask layer 140 to form a combined etch mask.
• FIGS. 5B and 8B show a different example.
• materials A and B have been removed, such as by directional etching.
• materials A and B can be removed one after the other, such as by using different etch chemistries, in other embodiments, materials A and B can be removed simultaneously while leaving lines of material A (that are not blocked by the patterned etch mask).
• Lines of materials herein can be removed simultaneously with etchants (process gas mixture) configured to etch two materials at a same rate.
• the two materials being removed can have a same chemical composition to facilitate simultaneous removal. Note that in FIGS.
• the two or more differing materials include three or more differing materials. Selectively removing at least one of the two or more differing materials can then include selectively removing two of the three or more differing materials resulting in corresponding portions of the patterned mask layer being uncovered.
• the two or more differing materials include four or more differing materials. Selectively removing at least one of the two or more differing materials then includes selectively removing two of the four or more differing materials resulting in corresponding portions of the patterned mask layer being uncovered.
• the pattern of alternating lines of two or more differing materials includes a repeating sequence of A-B-A-B in which material A and material B have different etch resistivities relative to each other, in other
• the pattern of alternating lines of two or more differing materials includes a repeating sequence of A-B-C-B-A-B-C-B in which material A and material B have different etch resistivities relative to each other.
• material C can have a different etch resistivity relative to material A and material B.
• the pattern of alternating lines of two or more differing materials includes a repeating sequence of A-B-C-D-C-B-A-B-C-D-C-B, wherein at least two of materials A, B, C and D have different etch resistivities relative to each other.
• a substrate can be provided having mandrels positioned on the underlying layer with the mandrels comprised of a first material.
• First sidewail spacers are then formed on exposed sidewails of mandrels.
• the first sidewali spacers are comprised of a second material.
• Second sidewali spacers are formed on exposed sidewails of the first sidewali spacers.
• the second sidewail spacers are comprised of a third material.
• Fill structures are then formed that fill open spaces defined between exposed sidewails of second sidewail spacers that face each other.
• the fill structures are comprised of a fourth material.
• Top surfaces of the mandrels, the first sidewail spacers, the second sidewali spacers, and the fill structures are all uncovered (exposed). At least two materials of the first material, the second material, the third material and the fourth material are chemically different from each other.
• a substrate can be provided having mandrels positioned on the underlying layer with the mandrels comprised of a first material.
• First sidewall spacers are then formed on exposed sidewalis of mandrels.
• the first sidewall spacers are comprised of a second material.
• Fill structures are then formed that fill open spaces defined between exposed sidewalis of first sidewall spacers that face each other.
• the fill structures are comprised of a fourth material. Top surfaces of the mandrels, the first sidewall spacers, and the fill structures are all uncovered (exposed). At least two materials of the first material, the second material, and the fourth material are chemically different from each other.
• a substrate can be provided having mandrels positioned on the underlying layer with the mandrels comprised of a first material. Fill structures are then formed that fill open spaces defined between exposed sidewalis of the mandrels. The fill structures are comprised of a fourth material. Top surfaces of the mandrels and the fill structures are all uncovered (exposed). At least two materials of the first material and the fourth material are chemically different from each other.
• An alternative method for forming two or three lines of alternating material is to execute a directed self-assembly operation of block copolymers to form alternating lines of differing material. Any other techniques can be used for forming ail or a portion of the multi-line layer including extreme ultraviolet lithography, direct write print pattern, self-aligned quad patterning, self-aligned double patterning, and so forth.
• techniques herein can include transferring a combined pattern 160 into the underlying layer 135.
• the combined pattern 160 is defined by mask material and remaining materials of the multi-line layer, in some embodiments, an additional layer in between the multi-line layer and the underlying layer can have a different etch resistivity as compared to other materials in the multi-line layer and can thus provide another etch selectivity option for controlling pattern transfer.
• the underlying layer can provide this additional etch selectively material and then a target layer below the underlying layer can be a target for pattern transfer.
• the underlying layer can be a memorization layer that receives the combined pattern during transfer of the combined pattern.
• This memorization layer can be comprised of material having a different etch resistivity relative to materials in the multi-line layer. With such a configuration, a given combined pattern can be transferred into the memorization layer, then a currently existing line in the multi-line layer can be removed, and a combined pattern transfer can be executed again.
• FIGS, 9A, 10A, 9B, and 10B show example patterned substrate segments after combined pattern transfer into underlying layer 135 and after having removed the patterned mask layer and multi-line layer.
• FIG. 9A is a cross-sectional side view that corresponds to top view 10A
• FIG. 9B is a cross-sectional side view that corresponds to top view 1 GB.
• transferring the combined pattern into the underlying layer can include cutting one or more buried structures within the underlying layer.
• the underlying layer can have buried fin structures or other features that can be cut or added to with the combined pattern transfer.
• a pitch of a given line of material in the two or more lines can be less than an optical resolution of a given photolithography system. This can be realized because mandrels can be formed by double or multiple patterning reduction techniques, and then additional materials can be deposited by atomic layer deposition or other highly controllable deposition techniques. Lines of material formed this way can have a half-pitch spacing that is less than 16 nanometers, [0043] FIGS.
• a substrate is provided having mandrels 1 11 positioned on underlying layer 135.
• the mandrels 11 1 are comprised of a first material.
• the substrate can include a silicon wafer.
• One or more additional underlying layers and/or buried structures can be included depending on a fabrication step of a given substrate within a given fabrication flow.
• Materials can include various nitrides, oxides, organics, metals, as well as other conventionally available materials.
• Mandrels 11 can be formed using conventional patterning techniques. For example, mandrels 1 11 can be a result of self-aligned double patterning or self-aligned quadruple patterning techniques and thus can have sub- resolution half pitches.
• First sidewall spacers 1 12 are formed on exposed sidewalls of the mandrels 1 11 as shown in FIG. 13.
• First sidewall spacers 1 12 are comprised of a second material.
• FIG. 13 shows spacers formed on vertical sidewalls of the mandrels 111.
• Forming first sidewall spacers 112 can include conformally depositing the second material on the substrate.
• FIG. 2 shows a first conformai film 122 having been deposited on the substrate 105.
• Such spacer formation is conventionally known.
• highly conformai deposition techniques such as atomic layer deposition (ALD) can be selected for depositing spacer material, which approximately uniformly covers mandrels 11 and underlying layer 135.
• ALD atomic layer deposition
• a spacer open etch can then be executed to complete formation of sidewall spacers.
• Such a spacer open etch is typically a directional etch that removes the second material from a top surface of the mandrels 1 11 and from the underlying layer 135 in between second material deposited on sidewails of the mandrels 11 (except where material on sidewails of mandrels covers the underlying layer 135).
• Second sidewall spacers 113 are formed on exposed sidewails of the first sidewall spacers 112 as shown in FIG. 15.
• the second sidewall spacers 1 3 are comprised of a third material.
• FIG. 15 shows spacers formed on vertical sidewails of the first sidewall spacers 1 12.
• Forming second sidewall spacers 13 can include conformally depositing the third material on the substrate.
• FIG. 14 shows a second conformai film 123 having been deposited on the substrate 105. Such spacer formation is conventionally known.
• highly conformai deposition techniques such as atomic layer deposition (ALD) can be selected for depositing spacer material, which approximately uniformly covers existing structures on the substrate, which can include mandrels 1 11 , first sidewall spacers 1 12, and patterned mask layer 140.
• a spacer open etch can then be executed to complete formation of sidewall spacers.
• Such a spacer open etch is typically a directional etch that removes the third material from a top surface of the mandrels 1 1 , the first sidewall spacers 112, and from patterned mask layer 140 in between third material deposited on sidewails of the first sidewall spacers 112 (except where material on vertical sidewails of structures covers the patterned mask layer 140).
• first sidewall spacers 1 12 define open space between each other prior to forming second sidewall spacers, in some locations, mandrel half-pitch can be shortened such that forming first sidewall spacers completely fills space between selected mandrel pairs and thus prevents forming second sidewall spacers in such a location.
• varying pitch of the mandrels can cause some merged spacers, either from the first sidewall spacers or the second sidewall spacers.
• Such a fabrication technique can be beneficial (for example) in forming power rails for integrated circuits,
• fill structures 114 are then formed on the substrate 105 that fills open spaces defined between exposed sidewalls of second sidewall spacers 13 that face each other (prior to forming the fill structures 114).
• the fill structures 1 14 are comprised of a fourth material. Fill structures 1 14 are formed such that top surfaces of the mandrels 1 11 , the first sidewall spacers 1 12, the second sidewall spacers 13, and the fill structures 114 are ail uncovered.
• Forming fill structures 1 14 can include depositing an overburden material 124 of the fourth material on the substrate.
• FIG. 18 shows overburden material 124 deposited on substrate 105, which can entirely cover existing structures.
• Various deposition techniques for depositing the overburden material 124 can be used including spin-on deposition. After deposition, overburden material 124 can be etched back, or otherwise pulled down, until the fourth material is recessed below top surfaces of the second sidewall spacers 113. The fourth material can also be recessed below top surfaces of first sidewall spacers 1 12 and mandrels 11 1.
• the patterned mask layer 140 can be formed thereon, such as a relief pattern of photoresist or hardmask material.
• trenches can exclude the fill structures and instead have trenches (un-filled lines) function as one or more lines of the multi-line layer.
• a multi-line layer is formed above the underlying layer.
• a patterned mask is formed on the multi-line layer.
• the multi-line layer includes a region having a pattern of alternating lines of two or more differing materials. In this region, each line has a horizontal thickness, a vertical height, and extends across the patterned mask layer, and each line of the pattern of alternating lines is uncovered on a top surface of the multi-line layer and vertically extends to a bottom surface of the multi-line layer. At least two of the two or more differing materials differ chemically from each other by having different etch resistivities relative to each other.
• the multi-line layer also defines trenches as part of the pattern of alternating lines of two or more differing materials. Thus, defined trenches extend parallel with lines of material and uncover a portion of the patterned mask layer.
• FIG. 15 One example of such a multi-line layer is shown in FIG. 15 as a multiline layer ready for pattern transfer or after positioning an etch mask thereon. Thus, in this particular example embodiment, depositing overburden material and pulling down the overburden material is omitted. This can be beneficial in some
• a given design can account for there being a pattern of trenches remaining in the multi-line layer and use these openings as the first pattern- transfer location. Accordingly, a combined pattern can be transferred into the underlying layer. The combined pattern is then defined by mask material and materials of the multi-line layer covering the patterned mask layer. Thus, with one line having no material, the initial pattern transfer can be executed without first having to selectively remove one of the lines.
• FIG. B Another example can be seen in FIG. B.
• the pattern in FIG. 1 B is A-B-C-B-A-B-C-B, which then repeats.
• forming material C can be omitted and thus where material C is indicated there would be a trench instead.
• This configuration can be created by forming material A as a mandrel, deposited material B conformally, and then executing a spacer open etch on material B to yield sidewail spacers on material A and with material B removed from the underlying layer.
• a multi-line layer 150 is formed on the underlying layer 35. Any line or combination of lines from multi-line layer 150 can be selectively removed, and then a combined pattern of remaining lines and patterned mask layer 140 can be transferred into underlying layer 135.
• a matrix of selectable materials and material combinations can be created to create features at desired locations and lengths that are below resolution capabilities of conventional photolithography systems.
• etched features themselves can be transferred into memorization layers and/or target layers, and can also be used to reverse patterns. Accordingly, two, three, four, five or more different materials can be accessed for selective etching.
• Self- alignment can be selected at various places on a substrate using an patterned mask and the differential etch selectivities of the different materials. In other words, with different materials of known dimensions, a designer can select where to execute an etch and have that etch be self-aligned at sub-resolution dimensions. For example, if a given contact pattern from a photoresist material is relatively large and spans multiple materials, a contact will only be etched at one of the materials within that particular contact pattern opening,
• techniques herein can be used to provide a pedestalized color scheme, that is, materials with differential etch selectivities.
• the pattern of alternating lines of material can be fabricated to have different pitches depending on design interests. Conventionally, if is very difficult to cut on pitch. Conventional photolithography systems can make cuts of about 42 nanometers. With techniques herein, however, a contact can be placed at will anywhere on a given substrate.
• This patterning technique also enables pitch splitting across colors. In some regions there can be a full half pitch between materials, while in other regions there are relatively large amounts of self-alignment, such as between mandrels. Moreover, by selecting two or more of available materials in which two of the materials are adjacent to each other, off-pitch or mixed-size etches can be executed. Thus, various pitch multiples can be made as a cut or a block with techniques herein,
• any 2-dimensionai multi- material layer can be formed on a substrate, and then any 2-dimensionai mask pattern can be formed on the multi-material layer.
• a cross point of the two layers provides sub-resolution patterning because the combination of the two layers and ability to selectively etch one or more of multiple uncovered materials, augments lithographic registration to provide many precise etch transfer operations and options including self-aligned gate and self-aligned block etches.
• substrate or "target substrate” as used herein genericaliy refers to an object being processed in accordance with the invention.
• the substrate may include any material portion or structure of a device, particularly a semiconductor or other electronics device, and may, for example, be a base substrate structure, such as a semiconductor wafer, reticle, or a layer on or overlying a base substrate structure such as a thin film.
• substrate is not limited to any particular base structure, underlying layer or overlying layer, patterned or un-patferned, but rather, is contemplated to include any such layer or base structure, and any combination of layers and/or base structures.
• the description may reference particular types of substrates, but this is for illustrative purposes only.

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