Next Generation DRAM

Centura Conforma

Doping is the process of introducing atoms of such elements as boron, arsenic, or phosphorus, into a semiconducting material (e.g., silicon) to alter its electrical conductivity. As device dimensions scale down, doping becomes increasingly vital to achieving desired drive current and suppressing leakage current to ensure maximum circuit performance, meet overall power consumption limits, and minimize device variation.

At advanced nodes, traditional beam-line doping technology is becoming severely challenged to productively achieve the required lower energies and the precision of dopant placement for increasingly shallow junctions over varying three-dimensional topographies. The Applied Centura Conforma, on the other hand, employs a Conformal Plasma Doping (CPD) process that is not subject to the limitations of line-of-sight doping and can also be performed with very high productivity at very low energies. This makes it a more universally effective method of doping emerging three-dimensional devices, such as finFETs and vertical NAND flash memory.

The Conforma system can operate in different modes for various doping applications, ranging from ion implant, to material modification, to conformal doping and deposition, the dose and energy requirements for which differ significantly. Its source technologies, which leverage Applied’s long-standing expertise in high-density plasmas, include an RF bias (bottom) source running in continuous wave mode for high ion flux rates and to avoid the risk of charging the wafer. The system also features unique in-situ chamber clean and seasoning capability. This not only minimizes contamination and improves process repeatability but enhances productivity by virtually eliminating consumables associated with process kit wear and allows the flexibility to rapidly switch from one dopant type to another without hardware changes.

The system is also uniquely capable of processing with undiluted hydride chemistries, which avoids the use of carrier gases that can result in significant unwanted changes to transistor characteristics. Some dopants are very volatile (e.g., arsenic); the Conforma system can deposit an in-situ silicon dioxide capping layer after the doping process to prevent dopant loss during the subsequent activation annealing process and to provide an increased margin of safety when the wafers are removed from the system with high surface concentrations of dopants.

Equipped with production proven components and running on the long-established Centura platform, the Conforma system delivers the most versatile doping and deposition capabilities for next-generation devices at the highest productivity and lowest cost of ownership.