Hermetic load and source pull wafer probe station
View Patent ↗A hermetically RF-EMI shielded 3-axis and planarity adjustable combo link assembly for low loss connection between the coaxial RF connector of external instruments (impedance tuners) with 30- or 45-degrees wafer probes allows continuous, micro-positioner controlled independent horizontal and vertical probe movement. Flexible sealing O-rings and RF absorbing sheets and gaskets ensure airtight and RF-EMI shielded operation.
1. An RF-EMI hermetically shielded, load and source pull wafer probe test station comprising:
an RF-EMI shielded chamber having a top cover, a bottom plate and sidewalls, and capability for carrying a semiconductor wafer on the bottom plate, and a combo, 3-axis (X-Y-Z) and planarity (THETA) adjustable, RF and DC connection assembly allowing double, direct, low-loss and shielded connection of a load and a source impedance tuner with wafer probes,
wherein the combo adjustable RF and DC connection assembly comprises: a first section and a second section of straight low-loss coaxial cylindrical airline, a master vertically sliding cylinder and a slave vertically sliding cylinder, and a plate covering an opening in the top cover of the RF-EMI shielded chamber;
wherein the vertically sliding cylinders have holes traversing diametrically under an angle (Φ) from near the top to near the bottom of the cylinders; the master cylinder has a first hole allowing the first section of coaxial airline to slide-fit inside it and a diametric secondary hole with a diameter large enough to allow to the traversing second section of coaxial airline free movement; the slave cylinder has a single hole allowing the second section of coaxial cylindrical airline to slide-fit inside it; and wherein the master cylinder slide-fits inside a hole in the covering plate, and the covering plate slides on the top cover of the RF-EMI shielded chamber; and wherein the master cylinder has a vertical cylindrical cavity, in which the slave cylinder is inserted and slides independently and RF-shielded inside the master cylinder; and
wherein the first section of coaxial cylindrical airline traverses the first hole of the master cylinder, and the second section of coaxial cylindrical airline traverses the secondary hole of the master cylinder and the single hole of the slave cylinder, and wherein the source and load pull impedance tuners are directly attached in-line to the coaxial cylindrical airlines and are controlled by external 3-axis positioners with planarity (THETA) adjustment and pivoting (Φ) capability, wherein pivoting (Φ) capability is the 3-axis position mechanism having a pivoting head that can be adapted to the probe angle (Φ); and
wherein all sliding contacts between surfaces are hermetically RF-EMI shielded.
2. The RF-EMI hermetically shielded, load and source pull wafer probe test station of claim 1 , wherein the angle Φ of the holes traversing the cylinders is 30 degrees.
3. The RF-EMI hermetically shielded, load and source pull wafer probe test station of claim 1 , wherein the angle Φ of the holes traversing the cylinders is 45 degrees.
4. The RF-EMI hermetically shielded, load and source pull wafer probe test station of claim 1 , wherein movement of the vertical cylinders is RF-EMI shielded using appropriate RF absorbing rubber O-rings.
5. The RF-EMI hermetically shielded, load and source pull wafer probe test station of claim 1 , wherein the external 3-axis positioners with planarity (THETA) and pivot (Φ) capability are attached to a platform of the wafer probe test station.
6. The RF-EMI hermetically shielded, load and source pull wafer probe test station of claim 1 , wherein the sliding surfaces between the coaxial airlines and the cylinders are hermetically RF-EMI shielded using tubular RF energy absorbing gaskets, and
wherein the sliding surface between the covering plate and the top cover is hermetically RF-EMI shielded using sheets of RF energy absorbing gaskets.