Rapid Thermal Processing

Rapid Thermal Processing (German: rapid thermal processing ) is an umbrella term for the processing of wafers in a high temperature process, in which a very rapid heating of the wafer with halogen lamps is achieved.

Basic principle

The introduced into the process chamber wafer is supported by several halogen lamps (usually 150-250 piece at 200 mm wafers ) heated with a total capacity of 40 kW or more at a temperature of about 1000 ° C.

Due to the high power of the lamps are heating rates ( engl. ramp-up ) of up to 400 Kelvin per second are possible. After switching off the halogen lamps of the wafer cools down again very quickly ( engl. ramp-down, about 50 degrees Kelvin per second). Most RTP processes take place under vacuum in order to avoid unwanted oxidation

Processes

Rapid Thermal Annealing

Rapid thermal annealing (RTA, dt: rapid thermal annealing ) is used to anneal the crystal structure of the wafer, for example by implantation processes. By this method, the crystal lattice defects are reduced in the treated wafers, thereby improving the electrical properties. To achieve this, the wafer is brought to temperatures around 1000 ° C for 10-20 seconds. Thus, minor dislocations in the crystal can balance and blend better any dopants at interstitial sites in the crystal lattice. However, the further diffusion of the dopants is limited to a minimum through the short process times.

Rapid thermal oxidation

Rapid thermal oxidation ( RTO, dt: rapid thermal oxidation) is used to generate very thin oxides ( <20 angstroms), primarily silicon dioxide on silicon substrates, for example, serve as a screen oxide for implantation processes. The process represents a further development of the thermal oxidation of silicon dar. In contrast to thermal oxidation, in which a plurality of wafers are simultaneously processed in an oxidation furnace, it is at RTO system generally to single-wafer processing equipment. RTO is in terms of oxide growth is not significantly faster than the oxidation in large oxidation furnaces, but you look at the entire process (loading, high heat, oxidation and cooling) reduces the time required from hours to a few minutes; but only for one instead of 50 wafers.

Further application

Production of titanium silicide by applying a titanium layer of 40 nm thickness and subsequent transformation into a silicide by RTP