Page 42 - Chip Scale Review Sep Oct_2022-digital

Figure 2: a) 100 touchdowns at -40°C; b) A zoomed-in view showing the temperature reliability of 10mK.
and probers. The tool is connected to a At 85°C, the observed temperature However, when looking at a timeframe of
temperature readout device and is controlled reliability increased slightly to around 30 minutes, a temperature reliability of
with software that communicates with the 30mK. This test was also performed 10mK was recorded.
prober, controller, and readout device. The with 100 touchdowns, which took Temperature drift. When performing
software allows the user to program the approximately five hours to complete. the 100 touchdowns at 200°C, a gradual
chuck to move to different positions for
temperature measurements.
Operation. A fully-automated calibration
process is possible, eliminating the problem
of loading the measurement wafer and
the time-consuming operation of using a
manual drop sensor. It also means that no
operator skills are required. By using the
specially developed software, the user can
define each measurement point, start the
operation and let it run independently. The
automation capability has been thoroughly
tested and fully integrated into software
provided by Supplier A.
Repeatability tests
To verify the ingenuity of the tool,
repeatability tests at various temperatures
were carried out on two different probers:
a manufacturing probing station from
Supplier B and an engineering probing
station from Supplier A. The sensor is
programmed to make contact with one
point on the chuck, separate, and then make
contact again, creating multiple, repeated
touchdowns. Figure 2a shows the test data
from 100 touchdowns at -40°C, with a
zoomed-in view on the right side (Figure
2b). It visualizes the repeated contact
between the sensor on the chuck surface
and the temperature decrease resulting from
their separation. Based on these results,
it could be observed that the temperature
reliability of the ERS tool at -40°C is Figure 3: a) A temperature drift was observed at 200°C over five hours; b) Looking closer at a shorter time
approximately 20mK. interval, the reliability remained at 10mK.

40 Chip Scale Review September • October • 2022 [ChipScaleReview.com]
40