A method of fabricating a CCD image sensor including one or more lateral overflow drains, the method comprising: forming a first mask layer over an insulating layer, wherein the insulating layer is disposed on a layer having a first conductivity type; patterning the first mask layer to create one or more first openings where channel stops will be formed; implanting one or more dopants of the first conductivity type through the one or more first openings and into the layer having the first conductivity type to form the one or more channel stops in the layer having the first conductivity type; removing a portion (706, 708) of the insulating layer exposed in the one or more first openings prior to forming a second mask layer over the first mask layer and the one or more first openings; patterning the second mask layer to create one or more second openings where the one or more lateral overflow drains will be formed, wherein each second opening is disposed in a portion of a respective first opening and a portion of the second mask layer is disposed in the remaining portion of each first opening; and implanting one or more dopants of a second conductivity type opposite the first conductivity type through the one or more second openings and into each channel stop to form the one or more lateral overflow drains disposed entirely within a footprint of the channel stop, characterised in that: removing the portion (706, 708) of the insulating layer comprises removing only a portion (706, 708) of the insulating layer exposed in the one or more first openings such that the insulating layer after removal of said portion acts as a protection layer in subsequent processing steps for the surface of the layer having the first conductivity type; and implanting the one or more dopants of the second conductivity type forms the one or more lateral overflow drains with only one edge of a footprint of the lateral overflow drain aligned with an edge of the footprint of the channel stop. forming a first mask layer over an insulating layer, wherein the insulating layer is disposed on a layer having a first conductivity type; patterning the first mask layer to create one or more first openings where channel stops will be formed; implanting one or more dopants of the first conductivity type through the one or more first openings and into the layer having the first conductivity type to form the one or more channel stops in the layer having the first conductivity type; removing a portion (706, 708) of the insulating layer exposed in the one or more first openings prior to forming a second mask layer over the first mask layer and the one or more first openings; patterning the second mask layer to create one or more second openings where the one or more lateral overflow drains will be formed, wherein each second opening is disposed in a portion of a respective first opening and a portion of the second mask layer is disposed in the remaining portion of each first opening; and implanting one or more dopants of a second conductivity type opposite the first conductivity type through the one or more second openings and into each channel stop to form the one or more lateral overflow drains disposed entirely within a footprint of the channel stop, characterised in that: removing the portion (706, 708) of the insulating layer comprises removing only a portion (706, 708) of the insulating layer exposed in the one or more first openings such that the insulating layer after removal of said portion acts as a protection layer in subsequent processing steps for the surface of the layer having the first conductivity type; and implanting the one or more dopants of the second conductivity type forms the one or more lateral overflow drains with only one edge of a footprint of the lateral overflow drain aligned with an edge of the footprint of the channel stop. removing the portion (706, 708) of the insulating layer comprises removing only a portion (706, 708) of the insulating layer exposed in the one or more first openings such that the insulating layer after removal of said portion acts as a protection layer in subsequent processing steps for the surface of the layer having the first conductivity type; and implanting the one or more dopants of the second conductivity type forms the one or more lateral overflow drains with only one edge of a footprint of the lateral overflow drain aligned with an edge of the footprint of the channel stop.