What is RTA Rapid Thermal Annealing?

Rapid thermal annealing (RTA), also known as rapid thermal processing (RTP), is a technique used in semiconductor manufacturing to manipulate the electrical properties of silicon wafers [1]. This is done by rapidly heating the wafer to high temperatures, exceeding 1000°C, for a very short duration, typically just a few seconds [1, 3]. After reaching the desired temperature, the wafer is then rapidly cooled [4].

The rapid heating and cooling cycle differentiates RTA from traditional furnace annealing, which heats wafers more gradually over a longer period [3]. This quick process offers several advantages, including:

• Reduced thermal stress: By minimizing the time the wafer spends at high temperatures, RTA helps to prevent warping or cracking caused by thermal expansion and contraction [6].
• Improved dopant activation: Doping is the process of adding impurities to silicon to control its conductivity. RTA can activate these dopant atoms more efficiently than furnace annealing [4].
• Sharper dopant profiles: The rapid heating and cooling of RTA creates steeper concentration gradients of the dopant atoms within the wafer, which can lead to improved device performance [4].

RTA is a crucial step in various stages of semiconductor device fabrication. Some of its applications include:

• Activating dopants to create p-type and n-type regions in transistors [4].
• Forming ohmic contacts, which are junctions between a metal and a semiconductor with minimal resistance [6].
• Repairing defects introduced during previous processing steps [5].

Overall, rapid thermal annealing is a vital process in the semiconductor industry, enabling the precise control of electrical properties within silicon wafers.