A method of forming a patterned photoresist layer having a hydrophobic surface is provided. The method includes forming a photoresist layer on a substrate and image patterning. The photoresist layer may comprise a polymeric material. The imaged photoresist layer may then undergo a two-stage post-exposure bake. A surface treatment may be performed on the photoresist layer in between the two-stage post-exposure bake. The surface treatment may include applying a siloxane solution on a partially post-exposure baked photoresist layer. The post-exposure baked photoresist layer may then be developed to form the patterned photoresist layer. The method may be used to form a hydrophobic photoimageable nozzle plate of a micro-fluid ejection head having improved mechanical properties and stable hydrophobic properties.