A method of forming metallic pillars between a fluid inlet and outlet for two-phase fluid cooling. The method may include; forming an arrangement of metallic pillars between two structures, the metallic pillars are electrically connected to metallic connecting lines that run through each of the two structures, the arrangement of metallic pillars located between a fluid inlet and a fluid channel, the fluid channel having channel walls running between arrangements of the metallic pillars and a fluid outlet, whereby a fluid passes through the arrangement of metallic pillars to flow into the fluid channel.