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ThermcoPoly

Polycrystalline silicon (also called "poly-Si" or "poly") is deposited at a low pressure (~500 mtorr) using silane (SiH4). The tube has a sloping temperature profile. Deposition temperature is ~620C for polysilicon and ~520C for amorphous silicon. This furnace can handle wafers up to 6 inch and is plumbed with Ge, PH3 and B2H6.

Picture and Location

 

The tool is located at 78FG on the Lab Map.

Background

 

Process Capabilities

Cleanliness Standard

 

  • Substrates allowed; Si, SiGe, SOI and quartz.  No glass or plastic wafers.  All wafers must be clean and free of fast diffusers (metals, sodium KOH, etc) for tylan 1 and 2.  Materials that could contaminate tylan4 are not allowed. For example, no photoresist.  Wafers must be fully inspected for complete photoresist removal following any lithography process before the pre-diffusion clean starts.
  • Wafer must have undergone a complete pre-diffusion clean within 60 mins of loading into an oxidation furnace.  The pre-diffusion clean is described in these web pages; Process Modules for Diffusion Cleans.
  • The following cleans are allowed: full pre-diffusion or LPCVD clean done at wbclean-1 and-2

 

 

Performance of the Tool

What the Tool CAN do

  • Deposit doped and undoped Si, SiGe, Ge.

 

What the Tool CANNOT do

  • Deposition thicker than 4 microns.

 

Process Monitoring

 

Contact List and How to Become a User

Contact List

The following people make up the Tool Quality Circle:

  • Process Staff: Maurice
  • Maintenance: Ted
  • Super-Users: J Provine

 

Training to Become a Tool User

 

Contact Process Staff

 

 

Operating Procedures (Quicksheet)

 

A.                 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 (3 for ThermcoPoly), then press Return.

5.      System should be running STBYPOLY;  in prochold; temperature 525c

 

B.                  Vent tube

1.      Press START (STBYPOLY recipe ends when boat is out)

2.      Load your wafers.

 

C.                 Load Recipe

1.      Enable Tube.

2.      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 (P620POLY, P620PH3, P620B2H6, P580POLY, P580PH3, P580B2H6 P550POLY, P550PH3, P550B2H6…), 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 (3 for ThermcoPoly), then press Return.

11.   Recipe parameters are time and PH3 or B2H6 flow in sccm.  (PH3 ranges 1 to 10, B2H6 ranges 1 to 20)

12.   Type  Delay Time (in the HH:MM:SS format) then press Return.

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

D.                 Run Program

1.      Press START to initiate recipe, after 10 seconds press START a second time to initiate the tube close.

2.      Monitor and log the lowest base pressure, the highest leak back pressure and the pressure during deposition.

3.      Wait for tube to process wafers. After deposition, the tube will ramp down to 525c and hold until you press START.  The tube will vent and open (~17 min).

4.      Unload your wafers after they have cooled several minutes.

5.      Press STOP button until tube is in standby.

6.      Compile the STBYPOLY recipe.

7.      Press START to initiate tube close.

8.      STBYPOLY will leakcheck tube and the stop in the process hold steo.

9.      Disable tube.

10.   Mute tube.

 E.                 If Leak Check Fails

1.      Put tube in standby.

2.      Compile POLYOUT recipe.

3.      Press START.  The recipe will reset temperature, backfill and then boat out.

 

Boat Calibration Procedure

 

                         With tube in Standby, vented and free to move in and out

1.      While pressing "enable" key, toggle "recipe" key until recipe 6 is displayed.

2.      Check tube status to confirm "boat cal" recipe is loaded.

3.   Press "Start" key.

      Boat loader will open to limit, close completely, and then open to load position.

      If boat calibration was successful tube status will go to "Complete"

4.     Press "Stop" key to put system in "Standby".

5.      While pressing "enable" key, toggle "recipe" key until recipe 1 is displayed.

6.     Check tube status to confirm desired recipe is loaded.

 


Process Monitoring and Machine Qualification

Tool Qualification Run

 

Frequency

To be completed after major maintenance such as a tube change or on a set schedule to be determined or as needed based on user feedback.

 

Procedure

  1.  Use two wafers with 1000A of SiO2 already deposited on silicon.
  2.  Clean at wbclean-1 and-2 in the following sequence; 5:1:1 H2O:H2O2:NH4OH ten minutes, rinse, 5:1:1 DI:HCl:H2O2 ten minutes, rinse, spin dry.
  3.  Load program P580Poly into furnace.  Time variable is 00:23:30.
  4.  Load wafers into boats using very clean tweezers or vacuum wand.  Load wafers with the major flat up into the boats in the following positions:

1st boat: (Front), 20 empty slots,

1st  two dummies, (slots 21 & 22)

1st boat:  two test wafers(slot 23 & 24),

1st boat: one dummy (slot 25)



 

Measure:

Use Nanospec to measure poly thickness at the flat, center, bottom, left and right on each wafer.  Test sites should be no more than about 15mm from the edge of the wafer.

 

Record:

On Badger report the average and standard deviation of the polysilicon thickness.  Add each month’s data point to the trend chart and update on the wiki page.

 

 

Responsibility

 

 

Recommendation to users with critical processes

 

Machine Status States

Red:

Yellow:

Green:

 

Process Monitoring Results

 

B2H6 Doping Data

 

 

B2H6 doping data: Growth rate and resistivity for various doping flows and Poly recipes.

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