Within the semiconductor industry there are numerous means for depositing coatings on wafers. These coating layers then need subsequent treatments both for their activation and modification as well as a means to release material stress and improve the properties of the films. Rapid thermal processing (RTP) and rapid thermal annealing (RTA) are used in this regard and involve highly controlled heating and cooling of the wafers. Thermal exposure of the wafer must be kept to a minimum in these processes (otherwise known as the thermal budget).
As device geometries continue to shrink, this becomes of even more critical importance. Kamet’s mineral insulated (MI) high temperature (‘exotic’) thermocouples can play a crucial role in closely monitoring operation temperatures, while our mineral insulated heating elements can assist with precise temperature control.
The role of RTP and RTA
Rapid thermal processing (RTP) was developed to minimize a wafer’s exposure to excess thermal energy by designing as short a process time as possible. Rapid heating is achieved through IR lamps, halogen lamps, lasers or electric heaters. The 3 main application areas for RTP are:
- The activation process: The process by which a semiconductor is converted into a conducting material. In this process, impurities are planted into the transistor and they are activated or moved into desirable locations using high temperatures for a short time.
- The material modification process: The formation of transistor contacts. In making transistor contacts, RTP is used in order to convert a material, e.g. nickel platinum, into a more robust and low-resistive nickel monosilicide that helps improve the properties of the contact.
- Improve the properties of the film. In this case, RTP can be used to densify films, which makes the film more robust and this improves the performance of the device.
Rapid thermal annealing (RTA) is a specific type of RTP used to affect the electrical properties of the wafer.
For these processes, very high temperatures are desired for good results, however, the wafers cannot be exposed to high heat for a long period of time for various reasons (e.g. it would diffuse the dopants too widely). Currently, typical spike anneals that are used for dopant activation last no more than a couple of seconds.
What heating and temperature solutions does Kamet offer for RTP and RTA?
In rapid thermal processing (RTP) and annealing (RTA), accurate temperature measurement and control are extremely challenging. Kamet offers customized components to facilitate both aspects of this critical process.
- Our high temperature thermocouples are specifically designed to ensure quick response times and accurate measurements in demanding environments.
- Our mineral insulated (MI) wafer heaters can be used to uniformly heat up wafers in RTP systems. Our MI heaters can heat up to 1000°C rapidly and can operate at normal voltage levels (120V – 230V) and specific low-voltage levels. This way, no electric converters are necessary.
- Microheaters can be a small custom designed heating solution for PVD.
Kamet’s thermocouple and heater designs are fully customizable to match each particular application environment.
What are the advantages of using high temperature thermocouples for RTP and RTA?
- Extremely accurate readings even at high temperatures
- Proper calibration of pyrometers
- Fast response times
- Full customization of the thermocouple and the mineral insulated sheath ensures a perfect match to even the harshest environment.
- Contributes to good replicability of the process
- On-wafer thin-film thermocouples can measure the complete surface temperature without the heat transfer that occurs when using wire thermocouples
- Cost effective solutions
- Can be bent to fit intricate spaces
- Top class quality from our long-term partner, ARi with 60 years of experience
- Non-destructive testing is available for extra quality assurance
More about our work for the semiconconductor industry you can read here. If you have any questions or like to talk to us about your application. Contact us.