Examples are disclosed that relate to planarizing substrates without use of an abrasive. One example provides a method of chemically planarizing a substrate, the method comprising introducing an abrasive-free planarization solution onto a porous pad, contacting the substrate with the porous pad while moving the porous pad and substrate relative to one another such that higher portions of the substrate contact the porous pad and lower portions of the substrate do not contact the porous pad, and removing material from the higher portions of the substrate via contact with the porous pad to reduce a height of the higher portions of the substrate relative to the lower portions of the substrate.