Fabrication of Electroless CoWP/NiB Diffusion Barrier Layer on SiO[sub 2] for ULSI Devices

Abstract

We investigated the electroless CoWP/NiB diffusion barrier layer for ultralarge-scale integration (ULSI) interconnection by forming the immobilizing Pd catalyst on an organosilane layer. When the electroless CoWP film was formed directly on a Pd-activated organosilane layer, it became islandlike and did not form a continuous layer. When it was formed on an electroless NiB deposited on a Pd-activated organosilane layer, the electroless CoWP film was uniform and formed a continuous layer 10 nm thick. The transmission electron microscopy images of the interfaces of Cu/CoWP/NiB/SiO2 showed that, at an annealing temperature up to 400°C for 30 min, the interfaces remained unchanged and clear, showing no trace of Cu diffusion into the SiO2 substrate. In-plane X-ray diffraction patterns indicated that the CoWP/NiB film had an amorphous structure and was stable against heat-treatment up to 500°C for 30 min. An evaluation of sheet resistance measurements suggested that the CoWP/NiB film shows appropriate barrier properties for Cu diffusion up to 400°C . The CoWP/NiB film was used as a seed for electroless Cu plating. Trenches 100 nm wide were coated with a 10 nm CoWP/NiB barrier followed by successful trench filling by electroless Cu plating.

Conformal Electroless Deposition of Barrier and Cu Seed Layers for Realizing All-Wet TSV Filling Process

“…Formation of highly reliable barrier metal layer on the dielectrics surface within deep TSV is such a challenging topic. There are many studies on electroless Ni-alloy or Coalloy deposition on flat Cu surface [1][2][3][4], however, there have been only a few studies on barrier layer deposition on realistic TSV structure. We studied electroless conformal plating of barrier metals using Au-NP catalyst, and then tried to deposit electroless Cu for seed, and subsequent superfill of Cu by electroplating.…”

Direct Cu Electrodeposition on Electroless Deposited NiWP Barrier Layer on SiO2Substrate for All-Wet Metallization Process

“…4,[13][14][15] Since electroless deposited Ni-or Co-based alloy layers possess desirable barrier layer properties, the application of electroless deposition to conformal barrier layer formation with Ni-or Co-based alloy layers has been studied. 5,8,[9][10][11][12]16 Moreover, various researchers have attempted to achieve a so-called "all-wet metallization process" by using an electroless deposited barrier layer. [9][10][11][12]17 The conventional all-wet metallization process includes barrier layer electroless deposition, seed layer formation, and Cu electrodeposition.…”

“…5,8,[9][10][11][12]16 Moreover, various researchers have attempted to achieve a so-called "all-wet metallization process" by using an electroless deposited barrier layer. [9][10][11][12]17 The conventional all-wet metallization process includes barrier layer electroless deposition, seed layer formation, and Cu electrodeposition. To form a barrier layer by electroless deposition on a dielectric substrate such as SiO 2 , most studies have created a self-assembled monolayer (SAM) prior to electroless deposition in order to immobilize the catalytic particles.…”

“…To form a barrier layer by electroless deposition on a dielectric substrate such as SiO 2 , most studies have created a self-assembled monolayer (SAM) prior to electroless deposition in order to immobilize the catalytic particles. [9][10][11]17 Generally, the use of a SAM improves catalytic nanoparticle coverage as well as adhesion between the electroless deposited film and the substrate. Some researchers have used 3-aminopropyl-triethoxysilane (APTES) to form a SAM and then, by using electroless deposition, have fabricated a Ni-or Co-based alloy barrier layer on the SiO 2 substrate.…”

“…Some researchers have used 3-aminopropyl-triethoxysilane (APTES) to form a SAM and then, by using electroless deposition, have fabricated a Ni-or Co-based alloy barrier layer on the SiO 2 substrate. [9][10][11] However, because electroless deposited Ni-or Co-based alloy layers are highly resistive, a Cu seed layer is formed before undertaking Cu electrodeposition. Usually, Cu seed layer formation on an electroless deposited barrier layer is conducted by using Cu electroless deposition and/or by means of a displacement reaction between Cu ions and the barrier material.…”