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Advanced interconnects development requires introduction of porous ultra low k (ULK) dielectrics enhancing product performance through parasitic capacitance reduction. ULK layers are characterized by higher carbon content and lower mechanical properties due to porosity increase. Consequently, ULK dielectrics are more prone to be damaged during plasma treatment in interconnects build [1]. Pre-clean processes prior to barrier/seed deposition are a potential area of concern for ULK integrity. Reactive pre-clean processes based on He/H"2 plasma are investigated in this paper through two types of hardware. The new pre-clean chamber is an upgrade of conventional pre-clean hardware and combines optimized H"2 plasma and active wafer temperature control to ensure efficient copper oxide reduction [3] and via cleaning. The aim of the paper is to evaluate performance of the new generation of reactive pre-clean compared to conventional hardware. To overcome ULK dielectric integration challenge, pre-clean processes need to ensure efficient copper oxide reduction and via bottom cleaning with minimum impact on ULK material properties. The ''new reactive pre-clean'' addresses these requirements for k=2.5 ULK materials. The new reactive pre-clean demonstrates a robust process window over a wide range of temperature and pressure settings for all characterized aspects. The ''new reactive pre-clean'' technology is seen to be a promising pre-clean candidate for next generation of porous ULK dielectric material ([email protected]?2.5) integration for 28nm node and beyond.

Two seed deposition hardware are compared in this paper: a standard Self Ionized Plasma (SIP) standard chamber and a new generation chamber allowing Cu deposition and re-sputtering simultaneously. TEM characterizations exhibits better features coverage for new seed generation thank to process fine tuning. It induces defectivity improvement and void density is reduced with new hardware. Furthermore, reliability performances are improved without degrading parametrical results.

The paper deals with the introduction of an innovative self-aligned capping layer leading to the formation of a Cu/Si/N mixed interface. The process was first developed targeting the aggressive 65 nm technology node and below. After optimisation, the process was successfully introduced in a well known Cu/FSG integration scheme prior to SiN etch stop layer deposition; process interest and maturity was demonstrated on 300 mm wafers in a 110 nm technology node by showing both its full compatibility with industrial requirements for stabilized technology and clear performance improvements in terms of electrical performance, defectivity and resistance to electromigration. These results open large perspectives for the integration of a Si-based self-aligned barrier on Cu lines, the process capability covering several technology nodes used either in addition to thin dielectric barriers or as a single capping of the copper lines.