00:04 Double pattern in VLSI is used for fabricating most space using light of 130nm wavelength 00:44 Moving to lower technology nodes affects security and quality due to diffraction of light. 01:20 Double patterning splits dense metal patterns into two masks. 01:55 Double patterning involves using mask one and mask two for higher density. 02:30 Double patterning increases fabrication cost 03:09 Double patterning techniques are useful in advanced node technology like finfet. 03:51 Double pattern process involves deposition and etching steps. 04:32 Double pattern used for higher density and better resolution in layout.