Fraunhofer Institute for Electronic Nano Systems
Fraunhofer Institute for Electronic Nano Systems

Nano Device Technologies

Barrier and Metal Chemical Vapour Deposition (CVD)

Development and optimization of chemical vapor deposition for diffusion barriers and copper

 

Research and development topics

Fraunhofer ENAS has long experience on the field of chemical vapor deposition for copper and diffusion barriers for copper.

Barrier and Copper CVD are used for metallization of interconnect schemes as alternative for PVD and electroplating. CVD processes gain an importance for 3D integration particularly, where structures with very high aspect ratios (AR) are to metallized.

 

CVD of diffusion barrier: TiN

  • Precursor: TDMAT
  • Multistep process consisting of alternating MOCVD deposition and plasma treatment steps
  • Process optimization for high step coverage with regard to pattern geometry and density
  • Stabilisation with SiH4 for better diffusion barrier properties at structure sidewalls
  • Deposition of adhesion layer for copper CVD, e.g. for passing CMP process

 

Copper CVD

  • Thermal MOCVD with CupraSelect™
  • Complete fill of structures
  • Deposition of seed layers for electroplating
  • Metallization of through-silicon vias (TSV): with barrier/seed for geometries > 3 µm; complete CVD fill for geometries < 3 µm
  • Process optimization for high step coverage with regard to structure geometry and depth, also very high aspect ratios (e.g. > 20)
  • Metallization of nanosized interconnects (< 100 nm)

 

Screening of new metal-organic precursors

  • Evaluation of new copper precursors for thermal deposition or reactive deposition
  • Testing of other precursors for metal, metal alloy and barrier deposition (e.g. Ru, Sn, Mn)

 

Equipment

The department Nano Device Technologies of Fraunhofer ENAS uses commercial tools like an Applied Materials P5000™ equipped with three CVD chambers (two for Cu-CVD and one for TiN-CVD) and a plasma pretreatment chamber. The two Cu-CVD chambers are based on WxZ chambers and have different evaporation systems for liquid precursors, a Bronkhorst system with a Liquid Delivery System and a direct Liquid Injection system from ALTATECH.

We process 200 mm wafers, however with adapter also smaller wafers can be coated.