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Thin Film Stress Machine - Internal Resources

iLab Name: Stress machine

iLab Kiosk: BRK Metrology Core
FIC: Shared
Owner: Rich Harlan
Location: Cleanroom - R/S Chase
Maximum Wafer Size: 8"/200 mm

Overview

General Description

The Thin Film Stress Machine is a non-destructive testing tool used to analyze the stress of thin films. The stress machine analyzes the radius of curvature of your whole wafer prior to the film being deposited. Then after film deposition, the stress machine reanalyzes your sample to compare to the original. This change in radius of curvature will then result in a film stress value in the units of MPa.

Specifications

Capable of 4, 5, 6, and 8 inch whole wafers
Can measure film stress from ambient to 500°C
Can measure film stress over a period of time
Capable of graphing time vs stress, and temp vs stress
Capable of measuring deflection of the substrate
Nitrogen reduces oxidation during heating
CDA can assist in cooling

Technology Overview

Sample Requirements and Preparation

Note: You must know your substrate thickness and film thickness to achieve a proper stress value

Standard Operating Procedure

1. SAFETY REQUIREMENTS

2. EQUIPMENT

3. TOOL CONFIGURATION

Figure1

Figure1
Figure2
Figure3

4. CYCLE OF OPERATION

Verify the tool is powered up and ready to use. Refer to Section 6 for the Start-up procedure.
Verify the Baseline performance check has been completed prior to measuring any samples.

BASELINE

Select the square locator fixture for the baseline measurement.
Open the front door (Figure1) and place the square locator fixture in the measurement chamber making sure the fixture is aligned to the three (3) alignment pins in the chuck.
Position the flat mirror standard inside the square so the mirror is against the back and right-side edges of the locator fixture shown in Figure2.
Close the front door.
Select “Process programs” in the “Edit” dropdown window:
Click on the “Load” button
Select the “mirror670.PRC” process program
Select the “Measure” dropdown at the top of the page
Select the “First (no film)” option
Type in a unique name next to “file:” and a unique number next to “ID”
Select the “Measure” button
The tool will scan the standard and display the Radius value as well as the bow value (red font) displayed on the graph.
Open the door to remove the flat mirror
Exchange the flat mirror with the “R=20.069M” curved mirror so the mirror is positioned against the back, right corner of the locator fixture as shown in Figure2.
Close the front door
Scan the curved standard and record the value
Select “Process programs” in the “Edit” dropdown window:
Click on the “Load” button
Select the “mirror780” process program
Select the “Measure” dropdown at the top of the page
Select the “First (no film)” option
Type in a unique name next to “file:” and a unique number next to “ID”
Select the “Measure” button
The tool will scan the standard and display the Radius value as well as the bow value (red font) displayed on the graph.
Open the door to remove the flat mirror
Exchange the flat mirror with the “R=20.069M” curved mirror so the mirror is positioned against the back, right corner of the locator fixture as shown in Figure2.
Close the front door
Scan the curved standard and record the value

SAMPLE MEASUREMENT

Open the front door and verify there are no other locator fixtures inside the tool.
The 100mm locator fixture has several different orientation options, most will use 0°, record the orientation used. The same orientation must be used during the second measurement to get usable measurements. There is a black line marked at the 3:00 position for the 0° orientation.
Place the wafer sample inside the locator fixture with the flat aligned with the ring and the wafer lying flat in the measurement chamber with the polished side facing up.
Close the front door.
Select “Process programs” in the “Edit” dropdown window:
Click on the “Load” button
Select the desired process program
Select the “Measure” dropdown at the top of the page
Select the “First (no film)” option
Enter (and remember) the “File:” name that is entered (example 200202.DAT)
Enter (and remember) the “ID:” number that is entered
Press the Measure button
Remove the substrate and grow/deposit the film.
Place the wafer in the fixture using the same orientation
Select the “Edit” dropdown window and select “Process Programs”
Select the same recipe used for the first/no film measurement
Select the “Measure” dropdown and select “Single”
Enter the same filename used for the first measurement
Enter the same ID that was used before
Enter the film thickness
Press the measure button

The stress value will be displayed on the top graph in MPa units