Method of making a planar charge coupled device with edge aligned implants and interconnected electrodes

A method of fabricating, at a region of first conductivity type in a semiconductor substrate, a planar, two phase charge coupled device with charge transfer direction biasing implants, the geometry of each charge transfer direction biasing implants being defined by a single mask level, the charge transfer direction biasing implant underlying and self-aligned to electrically connected first and second conductive strips, the steps comprising:

• (a) forming an insulative layer uniformly overlying a first conductivity type semiconductive substrate;
• (b) implanting in the semiconductive substrate second conductivity type impurity ions;
• (c) patterning, a first conductive layer on said insulative layer to form spaced first conductive strips;
• (d) implanting second conductivity type impurity ions into the semiconductive substrate the implant blocked in regions covered by the first conductive strips;
• (e) oxidizing the exposed first conductive strips to establish an insulating layer surrounding the first conductive strips;
• (f) uniformly depositing a second conductive layer;
• (g) planarizing said second conductive layer thereby removing the second conductive layer from regions in which the second conductive layer overlaps the first conductive strips at least to the extent that the second conductive layer is patterned into electrically isolated second conductive strips;
• (h) etching grooves between alternate pairs of first and second conductive strips, the grooves contiguous with portions of the first and second conductive strips;
• and
• (i) filling said grooves with a conductive interconnect material to form first and second planar composite electrodes.