US 12,455,507 B2
Method for removing material overburden via enhanced freeze-less anti-spacer formation using a bilayer system
Charlotte Cutler, Hopkinton, MA (US); and Michael Murphy, Latham, NY (US)
Assigned to Tokyo Electron Limited, Tokyo (JP)
Filed by Tokyo Electron Limited, Tokyo (JP)
Filed on Jun. 2, 2022, as Appl. No. 17/831,047.
Claims priority of provisional application 63/195,756, filed on Jun. 2, 2021.
Prior Publication US 2022/0388232 A1, Dec. 8, 2022
Int. Cl. G03F 7/40 (2006.01); B29C 71/00 (2006.01)
CPC G03F 7/40 (2013.01) [B29C 71/0009 (2013.01); G03F 7/405 (2013.01); B29K 2995/0059 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method of patterning a substrate, comprising:
forming a relief pattern including relief structures on a substrate from a first layer of photoresist on the substrate, the first layer of photoresist including a first solubility-shifting agent and a second solubility-shifting agent, the photoresist having a sensitivity to the first solubility-shifting agent and the second solubility-shifting agent, the relief pattern formed by activating the first solubility-shifting agent using a pattern of actinic radiation and developing the first layer of photoresist;
depositing a polymer mixture on the relief structures, the polymer mixture filling openings defined by the relief pattern and covering the relief structures, a region above top surfaces of the relief structures being an overburden region, the polymer mixture including a first polymer and a second polymer, the polymer mixture being configured to self-segregate relative to gravity such that a first film and a second film are formed from the polymer mixture, the first film including the first polymer formed below the second film including the second polymer, the first film and the second film formed such that the second film fills the overburden region, the first film being sensitive to the second solubility-shifting agent and having a threshold of sensitivity that is less than a threshold of sensitivity of the photoresist, the second film being soluble to a first developer;
activating the second solubility-shifting agent and diffusing the second solubility-shifting agent a predetermined diffusion length from the relief structures into the first film, the second solubility-shifting agent activated sufficiently to meet the threshold of sensitivity of the first film without meeting the threshold of sensitivity of the photoresist, diffusion regions formed in the first film becoming soluble to the first developer while the photoresist remains insoluble to the first developer; and
developing the substrate to remove the second film and the soluble diffusion regions of the first film.