Igor J. Malik

A plasma immersion implantation system for materials modification

Abstract A plasma immersion ion implantation (PIII) system is described which provides the capability to bridge the range between research exploration and commercial applications for materials modification of electronic materials, with a particular focus on layer transfer processes. The Silicon Genesis PIII system is capable of operation at high plasma densities (≈5×10 11 ions/cm 3 at the wafer) with high purity, mono-species ionization (>99% H + ions with a hydrogen plasma). The first generation of Silicon Genesis PIII systems is equipped to use 200-mm wafers (through an automated loadlock) and pulsed potentials up to 50 kV. Use of the mono-species ionization characteristic of the Silicon Genesis PIII system provides the capability to precisely vary the characteristics of surface layers through implantation of atoms and damage creation at well-controlled depths in the materials of choice. The Silicon Genesis PIII system is designed for efficient production of SOI and other layer transfer-generated materials and can be adapted for materials modification of more complex structures and work pieces.

Atomic-Layer Cleaving and Non-contact Thinning and Thickening for Fabrication of Laminated Electronic and Photonic Materials

An innovative suite of layer transfer technologies, collectively called the NanoCleave TM Process, includes a non-porous cleave plane utilizing a compressive strain layer, growth of a high purity, crystalline device layer, plasma activation coupled with vacuum bonding, room-temperature cleaving along an atomically flat plane and a variety of post-cleave CVD processes to thicken or thin the device layer to a desired final thickness is described. Applications of this process include fabrication of SOI wafers containing Si and SiGe alloy device layers.

Post-CMP cleaning of W and SiO2: a model study

Chemical-Mechanical Planarization (CMP) of SiO 2 is performed using alkaline silica slurries while CMP of tungsten (W) utilizes acidic slurries with alumina as the abrasive. Proposed mechanisms for the two CMP processes, with more emphasis on SiO 2 -CMP, have been discussed in literature. However, much less is known about the removal mechanism of residual slurry particles from the planarized surfaces - a crucial step for subsequent device processing. We discuss the chemical and physical basis of post-CMP cleaning by double-side scrubbing using polyvinyl alcohol (PVA) brushes and show how the interactions between the wafer surface, slurry, and the brush material affect the overall cleaning efficiency. Using the zeta potential concept the common features for cleaning surfaces after SiO 2 -CMP and W-CMP are established and the differences between these two systems are highlighted. We present surface particle levels for two model systems as a function of cleaning chemistries and discuss their influence on post-CMP surface metal levels.