3 Automatic Needle Alignement
3-2
This chapter explains the operations and parameter settings related to pad registration, needle
position alignment and needle height alignment. For other operation procedures, refer to the
respective chapters.
Points of operation
•
When attempting to perform automatic probe-pad alignment on a new device for which the
pad data is yet to be registered, pad registration will be requested after the alignment of the
initial wafer.
Once the necessary pads have been registered, the pad data are stored in the Device data
file, and are reused future lot processing of the same Device.
•
During pad alignment, probe tips do not contact the pads; only the probe tip positions
calculated from their images are compared to the corresponding pads. Therefore, when
using a multi-site probe card, pad positions are compared, not against probe images for a
single channel, but against the most appropriate probe images selected from across the
sites.
Upon completion of alignment, the chuck’s X, Y, and theta axes are automatically adjusted
to align the pads to the determined probe tip positions.
•
When performing contact height determination under the control of a tester, the chuck is
lifted by the tester, and the probe tips actually contact the wafer. To protect the probes and
the wafer, dice must be selected appropriately, thus requiring a wafer map to be prepared
in advance.
Needle height adjustment can also be calculated from the probe heights measured during
pad alignment. While this method does not require the probes to contact the wafer, the
standard procedure is to manually leave a probe mark on a pad, and a die must be
carefully selected for this purpose. This die must also be specified accurately on the wafer
map. (Manual confirmation of the probe mark is also required when performing height
alignment with a tester.)
•
On the secondary and succeeding wafers, the probe-pad alignment is not applied; the data
obtained on the initial wafer are used for the wafer X/Y/theta adjustment after the wafer
alignment for the correct placement of probe tips on the pads.
When the same probe card is used for the succeeding lot of the same Device (without the
probe card replacement and at using the same Device parameter file), the probe-pad
alignment does neither take place again nor confirmation on the probe-pad alignment is
demanded before the start of the lot process. For the probe-mark check on the lot first
wafer, you can stop Prober after positioning the first die and put probe-marks on the pads
of the first die with Z-DRIVE switch, and then you can confirm the probe-marks on the
screen.
•
Once you have turned on <Card Change> button in the preparation for a new lot, the
stored probe tip position data for the preceding lot are cleared.
On the other hand, even if the same probe card is used for the next lot where the wafers
have all the same pad arrangement to the preceding lot wafers, when another Device
parameter file is used, the stored probe tip data are cleared, too, and the probe-pad
alignment should take place.
