Electrochemical depositions of nanotwin copper materials

An electroplating method comprising:

• contacting a patterned substrate with a plating bath in an electroplating chamber, wherein the pattern substrate comprises at least one opening having a bottom surface and one or more sidewall surfaces;
• and
• forming a metal material in the at least one opening, wherein the metal material is formed by two or more cycles comprising:
• delivering a forward current from a power supply through the plating bath of the electroplating chamber for a first period of time, wherein the forward current is a pulsed current characterized by a duty cycle of less than or about 50%;
• plating a first amount of the metal on the bottom surface of the opening on the patterned substrate and a second amount of the metal on the sidewall surfaces of the opening, wherein at least a portion of the first amount of the metal is characterized by a nanotwin crystal structure;
• and
• delivering a reverse current from the power supply through the plating bath of the electroplating chamber to remove some of the metal plated in the opening on the patterned substrate, wherein the reverse current removes a greater portion of the second amount of the metal plated on the sidewall surfaces of the opening than the first amount of the metal plated on the bottom surface.