Method for forming and patterning a layer and/or substrate

A method for forming features for semiconductor processing, the method comprising:

• forming a first mandrel and a second mandrel on a substrate, the first mandrel and the second mandrel extending parallel to a first direction along the substrate;
• forming a first spacer along a first sidewall of the first mandrel and a second spacer along a second sidewall of the second mandrel, a first gap being defined between the first spacer and the second spacer;
• filling the first gap by a first gap-filling material, at least one of (i) the first spacer and the second spacer, and (ii) the first gap-filling material being boron-doped silicon;
• forming a third mandrel and a fourth mandrel on and across the first mandrel, the second mandrel, the first spacer, the second spacer, and the first gap-filling material, the third mandrel and the fourth mandrel extending parallel to a second direction along the substrate that intersects the first direction;
• forming a third spacer along a third sidewall of the third mandrel and a fourth spacer along a fourth sidewall of the fourth mandrel, a second gap being defined between the third spacer and the fourth spacer;
• removing a respective portion of (i) the first gap-filling material exposed through the second gap, or (ii) the first mandrel and the second mandrel exposed through the second gap;
• filling the second gap by a second gap-filling material;
• removing the third mandrel and the fourth mandrel, respective third gaps being formed by removing the third mandrel and the fourth mandrel;
• and
• removing a respective portion of the other of (i) the first gap-filling material exposed through the third gaps, or (ii) the first mandrel and the second mandrel exposed through the third gaps.