Wafer probe integration with load pull tuner
View Patent ↗Integrating a bracket with planarity adjustment holding a wafer probe securely, with a low-profile impedance tuner that is mounted on a 3-axis tuner positioner under an angle matching the angle of the wafer probe. The low-profile tuner has its tuning probe operating as close as physically possible within the distance of an RF adapter from the wafer-probe and is connected directly with the wafer-probe. This integration offers the maximum possible tuning range, while simultaneously offering planarity (THETA) control. It also eliminates the need for an extension RF cable between the instrument (tuner) and the wafer-probe, including a set of two coaxial adapters.
1. A low-profile load pull tuner for on-wafer operation, comprising:
a) a low-profile housing including electronic interface, at least one mobile carriage remotely controlled by stepper motor(s) and gear, and
b) a slabline comprising:
i) two sidewalls,
ii) a center conductor, a test port with an adapter and an idle port, wherein
the at least one mobile carriage slides parallel to the center conductor and has a remotely controlled, perpendicular to the center conductor moving axis, holding a metallic tuning probe insertable between the sidewalls,
iii) a bracket extension holding a wafer probe and controlling its planarity;
wherein
the low-profile tuner is mounted at an angle Φ matching an angle of the wafer probe, and
the adapter of the test port of the slabline is connected directly to the wafer probe;
and wherein
the wafer probe is attached to the bracket extension using a vertical flexible septum and a control mechanism of the planarity (THETA) of the wafer probe.
2. A method for mounting the low-profile load pull tuner of claim 1 on a wafer probe-station for highest tuning range at a DUT reference plane,
wherein
the low-profile tuner is mounted on a 3-axis positioner using a wedge-formed interface (WFI) matching the angle Φ of the wafer probe, whereby the adapter of the test port of the slabline is screwed directly on a coaxial connector of the wafer-probe.
3. The low-profile load pull tuner of claim 1 ,
wherein
the wafer probe comprises a body, a coaxial connector, an overhang and probe tips, the overhang having three vertical holes, a center hole and two side holes, all three holes being aligned perpendicular to an axis of the coaxial connector of the wafer probe;
and wherein the bracket extension holding the wafer probe comprises:
a L-shaped body having a horizontal and a vertical segment,
a vertical flexible septum,
a planarity controlling mechanism;
and wherein
the horizontal segment of the L-shaped body is attached from underneath to the wafer probe overhang using the vertical septum, which is held by a screw through the center hole of the overhang,
and wherein
the planarity controlling mechanism comprises two counter-balancing screws inserted into the side holes of the overhang pushing against the horizontal segment of the L-shaped body.
4. The low-profile load pull tuner of claim 1 ,
wherein
the wafer probe comprises a body, a coaxial connector, an overhang and probe tips, the overhang having three vertical holes, a center hole and two side holes, all three holes being aligned perpendicular to an axis of the coaxial connector of the wafer probe;
and wherein the bracket extension holding the wafer probe comprises:
a L-shaped body having a horizontal and a vertical segment,
a vertical flexible septum,
a planarity controlling mechanism;
and wherein
the horizontal segment of the L-shaped body is attached from underneath to the wafer probe overhang using the vertical septum, which is held by a screw through the center hole of the overhang,
and wherein
the planarity controlling mechanism comprises one balancing screw inserted into one side hole of the overhang and a pre-loaded spring inserted between an area below the other side hole and the horizontal segment of the L-shaped body.
5. A method for aligning and securing the wafer probe attached to the bracket extension of the low-profile load pull tuner of claims 3 or 4 , comprising the following steps:
a) loosen a screw securing the septum on the horizontal segment of the L-shaped body;
b) match and pre-tighten the test port adapter to the coaxial connector of the wafer probe;
c) adjust the planarity using the balancing screw(s);
d) verify the planarity of the probe tips;
e) if the planarity is not acceptable go to step c);
f) tighten the test port adapter to the coaxial connector of the wafer probe;
g) verify the planarity of the probe tips;
h) if the planarity is not acceptable, loosen the test port adapter and go to step c);
i) tighten the screw securing the septum.