Standard Operating Procedure
PVD-75 Sputtering Deposition System

Introduction

This page serves as a tutorial for the PVD-75 sputtering system and an introduction to the control system. At the bottom of this page, a PDF document may be found with the condensed SOP for the unit.

The PVD-75 Deposition system. Custom-built by Kurt J. Lesker, this sputtering system is currently configured with one RF target and one DC target. It is housed in the class-1000 cleanroom at Niagara College and utilized in both thin-film optical work (e.g. dielectric filters and mirrors) as well as semiconductor work.

This frontal view of the system shown the vacuum chamber on the left (with the touch panel control mounted on the door itself above the viewing window), and the control stack on the right. The control stack consists of two RF generators (only one is currently used) and one DC generator driving the sputtering targets. Actual configuration of the equipment in the stack is subject to change. The door on the right side of the system is normally kept closed since all controls and functions are accessed via the touchscreen.

System Elements:

The vacuum chamber, open, revealing three Torus three-inch sputtering guns. The front gun is #2 and is powered by the DC supply (normally this is aluminum). The rear right gun is #1 and is powered by the RF supply (normally it is an insulating material such an an oxide). The mounting platen for substrates is fixed at the top of the chamber onto the rotating shaft via two pins, the entire plate is rotated by hand until pins are aligned for the platen may be removed for substrate mounting.

At the very top of the chamber are two halogen heating elements as well as the intake for the turbomolecular pump behind the platen.

The touchscreen on the unit through which all functions are accessed. Buttons along the botton select individual functions including VACuum, DEPosition, GAS control, SUBSTrate control, RECIPE selection, and MAINTenance. The VAC screen is shown here. Pressing a gray button toggles a device (e.g. Roughing Pump) on and off (the button will turn green to denote it is on). Pressing a value highlighted with white text on a black background (e.g. 0 % for the turbo pump speed) allows values to be entered via a numeric keypad. This specific screen also displays the current chamber pressure via the WRG (Wide Range Gauge).

Procedures:

Start-Up

  1. Turn the cooling water ON (the red valve on the wall at the rear of the unit)
  2. Turn on the compressed air supply (also on the wall at the rear of the unit)
  3. Turn on the main tank valves on both the nitrogen and argon supply tanks
  4. Switch the main power shutoff on the wall to the right of the unit ON
  5. If the chamber is currently under vacuum (i.e. the pressure displayed on the WRG on the VAC screen is less than atmosphere), vent it before proceeding by selecting VENT from the RECIPE screen or pressing TURBO VENT to inject gas into the chamber (stop gas flow when the chamber is at atmosphere and can be opened).
  6. Load substrates into the chamber using the mounting clips
  7. Ensure the mounting platen is locked and close the chamber door

The vacuum screen. In this view, The ROUGHING PUMP is on as is the TURBO which has just started given the chamber pressure of 55 Torr.

Substrates, either glass or silicon wafers, are mounted to the 30cm diameter platen via small spring clips. The platen is rotated and the entire plate removed from the chamber, substrates are then mounted under clips as seen here. Once substrates are mounted, the entire platen is returned to the chamber and aligned with mounting pins.

Pump Down / Gas Control

  1. On the VAC screen, turn on the ROUGHING PUMP then the TURBO BACKING valve to start eacuating the chamber
  2. The WRG on the VAC screen will show pressure decreasing from atmosphere. When it falls below 100 torr, set the turbo speed to 50% (by pressing on the "0 %" speed selection) then enable the TURBO PUMP
  3. The WRG on the VAC screen will show pressure decreasing. Expected pumpdown to 1*10-5 torr is 20 minutes
  4. Select the GAS screen
  5. Turn the GAS INJECT on (the button will turn green)
  6. Select CTRL mode for MFC#1 (Argon) the button will turn green
  7. Set pressure set point (SETP) to the target pressure (e.g. 10 mTorr)
  8. The CAPMAN (Capacitance Manometer) will increase then show target pressure. If the pressure oscillates select the AUTO TUNE function which will set the PID control loop gains

The gas screen. In this view, GAS INJECT is on, the argon mfc is selected (CTRL), the pressure setpoint is 10.0 mTorr, and the actual pressure is 10.2 mTorr.

Deposition

  1. Select the SUBST screen
  2. Press MOTOR ROTATION to turn it on
  3. Set the Motor Speed to 5%
  4. Select the DEP screen
  5. Ensure the gas pressure (CAPMAN) is stable and at the target pressure

  6. For the DC target (aluminum, #2):
    1. Select PWS2 (Power Supply #2)
    2. Select SRC SW2 (Source Relay #2)
    3. Set the SETPT (Setpoint) to the desired power for aluminum (500W maximum)
    4. Set the RAMP to 5 W/s
    5. Set the SOAK time to the desired deposit time
    6. Press AUTO DEP to start the deposition
    7. The system will now ramp the power up then open the shutter. At the end of the deposition time the shutter will close and the power will ramp down.
    8. Set the SETPT (Setpoint) to zero

    For the RF targets (SiO, ZnO, MgF2 dielectrics, #1):

      NOTE: RF targets will not light properly unless the DC target is already glowing in the chamber. Failure to do this may result in sudden starting of the target at high powers (i.e. without a ramped power) which may crack the target.

    1. Select PWS2 (Power Supply #2)
    2. Select SRC SW2 (Source Relay #2)
    3. Set the SETPT (Setpoint) to 10W
    4. Turn the the DC supply on by pressing PWS2 ON which will now turn green
    5. The DC target MUST be lit and the plasma glowing before continuing. Do NOT proceed unless the DC target (front) is observed through the chamber window to be glowing (leave it on during the entire deposition)



    6. Select RF supply #1 using the PWS1 button
    7. Set the SETPT (Setpoint) to 300W
    8. Set the RAMP to 5 W/s
    9. Set the SOAK time to the desired deposit time
    10. Open the shutter for the RF target in use (#1)
    11. Press AUTO DEP to start the deposition
    12. The system will now ramp the power up. RF targets will not light immediately ignition will be delayed until a power of about 30W is reached.
    13. When the RF target lights (approximately 30W or power), CLOSE THE SHUTTER immediately using the button on the screen to avoid depositing material prematurely.
    14. The RF target MUST be lit and glowing before the RF power reaches 50W. If the target fails to light, Press STOP DEP immediately



    15. The system will now continue to ramp the power up after which the shutter will open and deposition will proceed for the soak time.
    16. After the deposition is complete, and the power has ramped down to zero, set the SETPT (Setpoint) to zero
    17. Select PWS2 and turn the DC power supply oiff

The substrate screen. In this view, MOTOR ROTATE is on and 5% speed is selected.

The deposition screen. In this view, Source 1 (SRC SW1) is selected, Power supply 1 is ON and operating at 55W. Note also the ACTUAL pressure is stable at 10.0 mTorr.

Venting

  1. Ensure all power supplies (#1 and #2) are OFF and set for zero output
  2. Select the GAS screen
  3. Turn the GAS INJECT off (the button will turn from green to gray)
  4. On the RECIPE screen, select VENT to start the vent cycle
  5. The WRG will show chamber pressure slowly increasing and the turbo speed decreasing
  6. Slowdown and vent time is up to ten minutes depending on the turbo speed setting
  7. At 50% turbo speed, the system will vent. If the vent operation fails, press ACK to acknowledge any errors and DONE to return to the main menu then manually select TURBO VENT to purge the chamber with dry gas and allow it to be opened.

Shutdown

  1. Ensure the turbo speed is zero and the chamber vented
  2. Turn off the main power switch on the wall beside the unit
  3. Turn the cooling water OFF (valve on the wall at the rear of the unit)
  4. Turn off the compressed air supply (also on the wall at the rear of the unit)
  5. Turn off the main tank valves on both the nitrogen and argon supply tanks

PDF Document outlining the basic procedures required to operate the PVD-75.


Updated 2018/06/21 by M. Csele

Copyright (C) Niagara College, Canada, 2018
This page is part of the SOP Repository Page