Self-aligned process using variable-fluidity material

A method of forming wide lines and narrow lines in a mask layer comprising:

• forming a mask layer;
• forming a pattern of lines on the mask layer, the pattern of lines including a plurality of lines spaced by first gaps where narrow lines are to be formed and a pair of lines spaced by a second gap where a wide line is to be formed, the second gap being wider than the first gaps;
• subsequently forming a portion of variable-fluidity material in the second gap, the portion of variable-fluidity material patterned to lie within the second gap without contacting either of the pair of lines;
• subsequently applying process conditions to the portion of variable-fluidity material to increase the fluidity of the variable-fluidity material and cause the variable-fluidity material to flow laterally within the second gap to contact the pair of lines;
• and
• subsequently patterning the mask layer by anisotropic etching while the variable-fluidity material remains in the second gap, the pair of lines and the variable-fluidity material in the the second gap defining the wide line, the plurality of lines spaced by narrow gaps defining the narrow lines.

A method of forming word lines and select lines comprising:

• forming a pattern of sidewall spacers on sides of mandrels including a plurality of closely spaced sidewall spacers formed on sides of narrow mandrels in a word line area and a pair of widely spaced sidewall spacers formed on sides of a wide mandrel in a select line area;
• subsequently removing the mandrels;
• subsequently forming a portion of variable-fluidity material in the select line area, the portion of variable-fluidity material initially formed in a substantially solid state within a gap that is bounded by the pair of widely spaced sidewall spacers, the portion of variable-fluidity material initially formed so that it is separated from the pair of widely spaced sidewall spacers on either side by at least a minimum distance;
• subsequently flowing the portion of variable-fluidity material to occupy a bottom surface of the entire gap that is bounded by the pair of widely spaced sidewall spacers;
• and
• subsequently patterning at least one underlying layer according to the pattern of sidewall spacers and the portion of variable-fluidity material, with word lines formed where the plurality of closely spaced sidewall spacers are located and select lines formed where the portion of variable-fluidity material lies in the gap that is bounded by the pair of widely spaced sidewall spacers.