A method for cosmetically treating skin tissue is disclosed in which a combination of laser energy and RF energy is applied to the skin tissue. In the method, a microchannel is first formed in the skin tissue having a length, a depth and a width by ablating the skin tissue. After that, RF electrodes are placed on the skin tissue on either side of the width dimension of the microchannel, followed by activation of RF energy to drive RF energy below the depth of the microchannel formed, and this the RF energy is driven deeper into the skin tissue than would have occurred in the absence of the microchannel.