KLA Tencor P-16+ - Rotecting the Tylus Rm Ssembly; System Provisions for Stylus Protection; Potential Stylus Damage During Scans; Table 2.2 Stylus Arm Assembly Protection

Basic Skills - Protecting the Stylus Arm Assembly KLA-Tencor P-16+ / P-6 User’s Guide
2-8 KLA-Tencor Confidential 0142530-000 AB
Friday, March 13, 2009
Preliminary
PROTECTING THE STYLUS ARM ASSEMBLY 2
System Provisions for Stylus Protection 2
The P-16+ / P-6 Profiler incorporates several design features that protect the stylus
from damage. (See Table 2.2)
Potential Stylus Damage During Scans 2
Despite precautionary features, there are still circumstances where damage can occur.
 Damage occurs whenever the stylus is down and a vertical wall that is fixed to
the stage moves against the stylus shaft.
 The stylus can be damaged whenever it encounters an obstacle higher than the
bevel height of the stylus tip (higher than 440
µm (17 mils) for the MicroHead
L-style stylus. (See Figure 2.6.)
Table 2.2 Stylus Arm Assembly Protection
Protection Name Stylus Arm Protective Measure Description of Result
Data Point Saturation During an ascending scan, the scan is
terminated when the stylus reaches its
upper limit of travel (when it has pivoted
up as high as it can go)
The stylus automatically retracts and the scan
is terminated. In the Scan window, the trace
ascends and flat lines at the top of its range.
Lowest Elevator
Position
As a safety factor, the elevator can be
programmed to lower only to a preset
limit.
With the
Lowest Elevator Position properly set,
when the measurement head is lowered, it only
goes as far as the setting allows, thus
protecting the stylus and sample from damage.
Proximity Sensor (P-16
Only)
The Proximity Sensor is designed to
detect the sample as the head lowers and
slow the descent.
With the Proximity Sensor ON, the head slows
and stops as it nears the sample surface.
If the Proximity Sensor is turned OFF, (or not
available, as in the P-6 model), then the head
descent slows when it reaches 1000 μm above
the Lowest Elevator Position. The system then
depends on the stylus contact with the sample
surface to stop the head descent. If the stylus
is coming down in a hole or off the edge of the
sample, the system or the sample could be
damaged by contact with the sensor assembly.