ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Chemical mechanical polishing (CMP) has been used as planarization process in thefabrication of semiconductor devices. The CMP process is required to planarize the overburden filmin an interconnect process by high relative velocity between head and platen, high pressure of headand chemical effects of an aqueous slurry. But, a variety of defects such as dishing, delamination andmetal layer peering are caused by CMP factors such as high pressure, pad bending and strongchemical effect. The electrical energy of the electro-chemical mechanical planarization (ECMP)dissolves copper (Cu) solid into copper ions electrochemically in an aqueous electrolyte. Thedissolved copper complex layer or passivation layer is removed by the mechanical abrasions ofpolishing pad and abrasive. Therefore the ECMP process realizes low pressure processing of softmetals to reduce defects comparing to traditional CMP process. But, if projected metal patterns wereremoved and not remained on whole wafer surface in final processing stage, Cu layer could not beremoved by ECMP process.The two-step process consists of the ECMP and the conventional CMP used in micro patterned Cuwafers. First, the ECMP process removed several tens 'm of bulk copper on Cu patterned waferwithin shorter process time than the Cu CMP. Next, residual Cu layer was completely removed by theCu CMP under low pressure. Total time and process defects are extremely reduced by the two-stepprocess
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.569.117.pdf
