Methods of forming fins include masking a region on a three-color hardmask fin pattern, leaving a fin of a first color exposed. The exposed fin of the first color is etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into a fin base layer using the fins of the first color and the fins of the third color.

Methods of forming fins include masking a region on a three-color hardmask fin pattern, leaving a fin of a first color exposed. The exposed fin of the first color is etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into a fin base layer using the fins of the first color and the fins of the third color.

Self-assembling materials, such as block copolymers, are used as mandrels for pitch multiplication. The copolymers are deposited over a substrate and directed to self-assemble into a desired pattern. One of the blocks forming the block copolymers is selectively removed. The remaining blocks are used as mandrels for pitch multiplication. Spacer material is blanket deposited over the blocks. The spacer material is subjected to a spacer etch to form spacers on sidewalls of the mandrels. The mandrels are selectively removed to leave free-standing spacers. The spacers may be used as pitch-multiplied mask features to define a pattern in an underlying substrate.

A method includes depositing a hard mask over a target layer. Depositing the hard mask includes depositing a first hard mask layer having a first density and depositing a second hard mask layer over the first hard mask layer, the second hard mask layer having a second density greater than the first density. The method further includes forming a plurality of mandrels over the hard mask; depositing a spacer layer over and along sidewalls of the plurality of mandrels; patterning the spacer layer to provide a plurality of spacers on the sidewalls of the plurality of mandrels; after patterning the spacer layer, removing the plurality of mandrels; transferring a patterning the plurality of spacers to the hard mask; and patterning the target layer using the hard mask as a mask.

A method includes depositing a hard mask over a target layer. Depositing the hard mask includes depositing a first hard mask layer having a first density and depositing a second hard mask layer over the first hard mask layer, the second hard mask layer having a second density greater than the first density. The method further includes forming a plurality of mandrels over the hard mask; depositing a spacer layer over and along sidewalls of the plurality of mandrels; patterning the spacer layer to provide a plurality of spacers on the sidewalls of the plurality of mandrels; after patterning the spacer layer, removing the plurality of mandrels; transferring a patterning the plurality of spacers to the hard mask; and patterning the target layer using the hard mask as a mask.

A multi-patterning method includes: patterning at least two first openings in a hard mask layer over a substrate using a first mask; forming spacers within two of the at least two first openings, each spacer having a spacer opening therein for patterning a respective first circuit pattern over the substrate, wherein each spacer defines a pattern-free region adjacent to a respective one of the at least two first circuit patterns, and patterning a second circuit pattern in the hard mask layer using a second mask. The second circuit pattern is located between and excluded from the pattern free regions adjacent the at least two first circuit patterns.

Methods of forming fins include masking a region on a three-color hardmask fin pattern, leaving a fin of a first color exposed. The exposed fin of the first color is etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into a fin base layer using the fins of the first color and the fins of the third color.

Methods of forming fins include forming mask fins on a protection layer over a seed layer. Seed layer fins are etched out of the seed layer. Self-assembled fins are formed by directed self-assembly on the seed layer fins. A three-color hardmask fin pattern that has hardmask fins of three mutually selectively etchable compositions is formed using the self-assembled fins as a mask. A region on the three-color hardmask fin pattern is masked, leaving one or more fins of a first color exposed. All exposed fins of the first color are etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into the fin base layer by anisotropically etching around remaining fins of the first color and fins of the third color.

Methods of forming fins include forming mask fins on a protection layer over a seed layer. Seed layer fins are etched out of the seed layer. Self-assembled fins are formed by directed self-assembly on the seed layer fins. A three-color hardmask fin pattern that has hardmask fins of three mutually selectively etchable compositions is formed using the self-assembled fins as a mask. A region on the three-color hardmask fin pattern is masked, leaving one or more fins of a first color exposed. All exposed fins of the first color are etched away with a selective etch that does not remove fins of a second color or a third color. The mask and all fins of a second color are etched away. Fins are etched into the fin base layer by anisotropically etching around remaining fins of the first color and fins of the third color.

Techniques herein provide a process to reform or flatten asymmetric spacers to form a square profile which creates symmetric spacers for accurate pattern transfer. Initial spacer formation typically results in spacer profiles with a curved or sloped top surfaces. This asymmetric top surface is isolated while protecting a remaining lower portion of the spacer. The top surface is removed using a plasma processing step resulting in spacers having a squared profile that enables further patterning and/or accurate pattern transfer.