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Thermco Oxidation and Annealing Furnaces, Thermco1 - 4

Thermco1-4 furnaces are used for wet and dry oxidation processing and N2 annealing.

Process Capabilities

Cleanliness Standard

Thermco1-3 are for clean work only.  The wafers processed in those furnaces are MOS clean, meaning that they have never had metal deposited on them, have been through a full KOH decontamination procedure and have not been processed in any equipment which is considered contaminated (sometimes referred to as ‘gold contaminated’).

Wafer must have undergone a full pre-diffusion or LPCVD clean done at wbdiff within 60 mins of loading into Thermco1-3.  The pre-diffusion clean is described in these web pages; Prediffusion Cleaning at SNF.

 

Thermco4 is gold contaminated.

 

Contact List and How To Become a User

Contact List

  • Process Staff: Maurice Stevens (maurice@stanford.edu)
  • Maintenance:  Ted/Ray
  • Super-Users: none

 

Training to Become a Tool User

Please follow the following procedure to become a qualified user of a thermco furnace:

  1. Read all material on the SNF website concerning the specific furnace, including Background, Process Capabilities, Operating Procedures and Process Monitoring.
  2. Contact a superuser or qualified user of the furnace to arrange to ‘shadow’ them while they use the tool.  The reservation option on coral will show who will be using the tool in the near future.  You are responsible to be with that labmember for the full time they are operating the tool, and it would be intelligent to ask questions and try to become as familiar as possible with the furnace during this ‘shadowing.’  You may have to shadow the superuser or qualified user more than one time.
  3. The labmember you choose to follow will have a Shadow Checklist (link to check list) for the furnace and you will have to be able to understand each point on it before the labmember notifies the staff responsible for training that you are ready for training.  Both of you must agree that you are ready.  You may have to shadow a labmember more than once.
  4. Contact the staff trainer to arrange for training on the furnace.
  5. If there is a written test for the tool you will need to hand it in to the staff member before training commences.
  6. After training you will be given  provisional qualification status.  This allows you to use the furnace during staffed hours, 0600-1800 Mon-Fri only.
  7. Once a superuser or staff member has watched you and you have satisfactory demonstrated the proper use the tool you will be granted a full qualification to use the tool anytime, 24/7.

 

Operating Procedures

Basic Operation Instructions

Check Tube Status

  1. Press Do key until Main Menu is reached.
  2. Use arrow keys to highlight Status Menu then press Return.
  3. Use arrows keys to highlight Tube Status then press Return.
  4. Type in Tube ID (1 for Thermco1, 2 for Thermco2), then press Return.

Thermco will now alternate between the Gas System screen and the Main Furnace screen.


Load Recipe

  1. Enable Tube.
  2. If tube is not in standby, press STOP button until tube is in standby.
  3. Press Do key until Main Menu is reached.
  4. Use arrow keys to highlight Recipe Menu then press Return.
  5. Use arrows keys to highlight Compile Recipe then press Return.
  6. Type in Recipe Name (1DRYOX, 2DRYOX, 1WETOX, 2WETOX, 1ANNEAL, 2ANNEAL), 3DRYO...), then press Return.
  7. For Recipe Name #2, press Return.
  8. For Parameter Table, press Return.
  9. Use arrow keys to highlight Download Only then press Return.
  10. Type in Tube ID (1 for Thermco1, 2 for Thermco2), then press Return.
  11. Type  Delay Time (in the HH:MM:SS format) then press Return.
  12. Enter Temp$ (example 800, 1000, 1050…) then press Return.

Thermco will flash orange Recipe Compile Succeeded once recipe is loaded.

 

Run Program

  1. Press START.  (Tube will boat out.)
  2. Load wafers.
  3. Press START.  (Tube will boat in.)
  4. Wait for tube to process wafers.
  5. Press START.  (Tube will boat out.)
  6. Unload wafers.
  7. Press START.  (Tube will boat in.)
  8. Disable tube.
  9. Fill out entries on logsheet.

 

Process Monitoring and Machine Qualification

Each month, tool qualification runs are performed on most tools in the SNF to monitor variations in each tool’s performance. The qual is performed by SUMO members, but users may perform the specified qual process before tool use if more recent qual data is desired for reference.

For more information on the SNF tool performance monitoring system and SUMO, please see the Monthly Tool Monitoring page under the Equipment tab on the SNF wiki.

 

Qual Process Overview

The tool will be reserved for 3 hours on Badger, as the run normally takes over two hours. Three freshly RCA cleaned 4" L test 100 Si wafers will be run in the WETOX recipe with a 39-minute oxidation time at 900 Celsius. Instructions are to be found in the appropriate binder located in the vicinity of the tool. Wafers are to be placed in a 50-wafer spread (as shown in Figure 1 below):

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Figure 1: Wafers are to be loaded with flats up and shiny side towards the door when the boat is out.

 

A 9-point spectroscopic ellipsometry measurement will be made on the Woollam for each wafer. The analysis strategy will be “Oxide on Silicon 100 - 10000 A,” located within the Silicon Oxide folder.

 

Reported Data

Qual data may also be found on the Badger comment log. The following data are reported for the Thermco quals. Standard data findings are listed in parenthesis.

  • average deposition thickness
  • min and max deposition thickness
  • one standard deviation value (0-15A)
  • index of refraction n at 633nm (1.4-1.5)
  • % non-uniformity (std dev/avg thickness) (0-1.5%)
 
Expected average deposition thickness: 950A - 1050A

 

Qualification Results


 

Machine Status States

  • Red:  The tool is not capable of depositing any films and needs maintenance or verification of proper working conditions.
  • Yellow:  The tool is capable of depositing some films or films outside of the acceptable range.  The cause will be explored by the quality circle.
  • Green:  The tool is in working condition for all available films, and those films were found to be within specifications.

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