| 20110284990 | Process for making an alignment structure in the fabrication of a semiconductor device - A process for making an alignment structure in manufacturing a semiconductor device, comprising copper interconnect (Cu-interconnect) fabrication involving chemical-mechanical planarization (CMP) is disclosed. The process comprises tailoring said CMP process to produce a sufficiently high dishing on a designated alignment key area during bulk removal of Cu. The additional dishing step would have sufficient step height for optical pickup to produce alignment signal. Subsequent photolithographic processes specifically for making conventional alignment structure may thus be omitted. Preferably, the additional dishing is achieved by control over any one or combination of pressuring, vacuuming and/or venting of a CMP head's membrane, inner tube and retaining ring chambers, and selection of any one or combination of pads, slurry, pad conditioner and recipe, and may only need to achieve a removal of up to 100 {dot over (A)}. Our process may be adapted for fabricating a MIM top and MIM bottom layers via 2 masking processes, wherein the additional dishing is created as a narrow metal line. It may also be adapted for fabricating an MIM capacitor wherein the underlying Cu layer is used as the bottom plate of the MIM. The additional dishing does not appear to affect electrical properties of the underlying Cu layer. | 11-24-2011 |
