Specific Process Knowledge/Thermal Process/RTP Annealsys

RTP Annealsys - Rapid Thermal Processor

This page is written by Inês Diogo@DTU Nanolab if nothing else is stated.

January 2023: The RTP Annealsys is being tested, but it is not released for general use yet. Please contact thinfilm@nanolab.dtu.dk for more information.

RTP Annealsys (RTP AS-Premium, serial number AS0415C4 - 7484, from ANNEALSYS) is a research tool available at DTU Nanolab that can reach very high temperatures in a matter of a few minutes or even seconds. Therefore, it is able to perform several types of rapid thermal processing and it can be used as a multi-functional and versatile microfabrication tool, within specific process windows for each process type, using Si/nanofabricated Si structures. Amongst them, there is rapid thermal annealing (RTA), hydrogenation (RTH), oxidation (RTO), nitridation (RTN), etc. Currently, it is used for rapid thermal annealing and smoothing of silicon-based samples.

The Set-Up

Schematic representation of the rapid thermal processor set-up profile view. The substrate (in green) rests on top of three quartz pins, supported by a quartz holder (in black). The drawing is not to scale. Image: Inês Diogo@DTU Nanolab, December 2022

The RTP Annealsys system is divided into two main parts: the process chamber and the loadlock.

The chamber has stainless steel walls (water-cooled) and a top and bottom halogen lamp-configuration (16 infra-red lamps, in total). As such, the samples are rapidly heated from both sides, simultaneously. In addition, the chamber is enclosed by two quartz-windows (immediately below/above the set of top/bottom lamps) and these are air-cooled. It is also connected to two external vacuum pumps, to a gas inlet and the loadlock.

Similarly, the loadlock is connected to two external pumps. Moreover, the chamber and the loadlock are separated by the gate valve. While processing, the valve remains closed; it is only opened to exchange the substrates when both chamber and loadlock are under turbo vacuum. The substrate transfer is possible due to the mechanical, retractable arm.

Temperature Measurement and Control

RTP Annealsys offers an optical pyrometry system for temperature measurement, not requiring any contact with the wafer.

Regarding setting the process temperature, it is also important to mention the tool can function under two distinct modes – power and temperature/pyro control modes. In other words, using power control mode, the tool is programmed to fix the lamp’s power at a specific value (%) and consequently, the temperature inside the chamber varies with time; using the temperature/pyro control mode, the tool is programmed to vary the lamps’ power to maintain the temperature stable and constant inside the chamber at a previously established value in the recipe.

Samples and Process Specifications

The RTP Annealsys, with a base pressure of 10^-6 mbar, is a research tool. As such, there are some parameters and details to consider.

Specifics		Allowed	Comments
Temperature		up to 1250 oC
Process gas	Ar	up to 2000 SCCM
	O2	up to 2000 SCCM
	NH3	up to 2000 SCCM
	5% H2/Ar	up to 2000 SCCM
Pressure	Valve (APC)	0o - 100o
	Controller	up to 12 mbar
Substrates	Batch size	Single-wafer process
	Substrate size	Chips on carrier 100 mm or 150 mm wafers
	Allowed materials	Silicon Silicon Nitride Aluminum Oxide

Previous work on RTP Annealsys

More information and details about each type of processing - achievable using the RTP Annealsys tool - can be found in the following documents.

• Report_Annealsys_December22 by Inês Diogo@DTU Nanolab

• Rapid Thermal Annealing and its Effects on High Aspect Ratio Silicon Features_MasterThesis_ID by Inês Diogo@DTU Nanolab

Important! The RTO sequences that were developed during the previous experimental work on the RTP Annealsys are not available to users. More tests and further investigation are required to prevent damaging the tool.

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