PICOPROBE® Models 28/29 | Active MOS Wafer Probe
Measures fast MOS signals directly on the wafer up to 1 GHz, with minimal loading of sensitive test nodes at just 0.04 pF.
- ✓ Active probe tips for MOS on-wafer measurements – Models 28/29 with 20:1 attenuation
- ✓ 0.04 pF input capacitance
- ✓ DC to 1 GH
Active Wafer Probes with Tungsten Wire for MOS On-Wafer Measurements up to 1 GHz
Wafer Probes for Fast MOS Signals
The active PICOPROBE® Models 28 and 29 probe tips route signals from contact points on wafers and integrated MOS circuits to a 50-ohm oscilloscope input. The active probes operate with 20:1 attenuation and a transmission range from DC to 1 GHz (-3 dB). With an input capacitance of 0.04 pF and an input leakage current of 10 fA, they place only a minimal load on small measurement nodes.
Probe Contact Points with Low Input Capacitance
In small MOS structures, any additional capacitance changes the signal at the measurement point. The low input capacitance limits this additional load; the probe tip transfers fast pulses with a rise and fall time of 350 ps to the oscilloscope. If you need active probe tips/probes with a different geometry, the PICOPROBE® Model 7/7A probes are an alternative.
Select Model 28 or Model 29 Based on Voltage Range
The voltage at the contact point determines the suitable model: Model 28 operates within a range of 0 V to +9 V, while Model 29 operates within a range of -7 V to +2 V. Both models transfer the signal to the 50-ohm input with a gain accuracy of ±3%.
Define Probe Geometry, Wire Diameter, and Replacement Tip
The suitable probe geometry depends on your wafer measurement setup, the micropositioner used, and the specific application. For custom setups, we coordinate the configuration individually. The choice of wire diameter depends on the contact area and contact behavior: tungsten wire with a diameter of 10 µm or 20 µm flexes during contacting and keeps the tip on the measurement point, even with slight table movement. Tungsten wire with a diameter of 50 µm provides higher stiffness and is therefore suitable for measurement setups with greater contact force. For passive RF and microwave contacting, the PICOPROBE® Model 10 series offers a 50-Ω alternative to the active high-impedance probes of the Model 28/29 series. Clarify the Right Probe with LXinstruments
Alternative Products
If you need to measure particularly sensitive MOS nodes with even lower input capacitance, we recommend the PICOPROBE Models 18C/19C with 0.02 pF, designed for frequencies up to 350 MHz. If you require a passive 50 Ω probe for broadband RF and microwave measurements, the PICOPROBE Model 10 Series with a frequency range up to 11 GHz is a suitable alternative.
Related Product Categories
Would you like to verify the model, probe geometry, and tip before ordering?
Send us the voltage range at the contact point, the planned oscilloscope input, and information about your wafer measurement setup using the contact form. Based on your setup, we determine the suitable configuration and recommend a version with the appropriate components.
Specifications
| Input capacitance | 0.04 pF |
|---|---|
| Input leakage | 10 fA |
| Frequency response | DC to 1 GHz (-3 dB) |
| Gain accuracy | ± 3% |
| Signal attenuation | 1 with 50-ohm input |
Rise/fall time: 350 ps
| Model 28 | for pulses up to +5 V |
|---|---|
| Model 29 | for pulses up to ±2.5 V |
Operating range:
| Model 28 | 0 V to +9 V |
|---|---|
| Model 29 | -7 V to +2 V |
Linearity:
| Model 28 | 0.5% over the 0 V to +4 V range; 2.0% over the 0 V to +9 V range |
|---|---|
| Model 29 | 0.5% over the -2 V to +2 V range; 2.0% over the -7 V to +2 V range |
Options & Accessories
Replaceable probe tips - ordering variants by wire and tip diameter (for both models):
| 28-5-5 | Wire diameter 5 µm, tip diameter < 0.1 µm |
|---|---|
| 28-5-10 | Wire diameter 10 µm, tip diameter < 0.1 µm |
| 28-5-20 | Wire diameter 35 µm, tip diameter < 1.0 µm |
| 28-5-50 | Wire diameter 50 µm, tip diameter < 3.0 µm |
PICOPROBE® Standard-Power Supply:
| 110 V | |
| 230 V |
Scope of Delivery
| PICOPROBE® Model 28/29, probe tip with tungsten wire – depending on configuration |
| Power supply – depending on configuration |
Applications
| On-wafer measurements on MOS circuits |
| Analysis of fast MOS signals up to 1 GHz |
| Measurements on capacitance-sensitive measurement nodes |
| IC development, prototyping, and verification |
| Contacting fine structures at wafer level |
| Signal testing and troubleshooting in laboratory setups |
Links & Downloads
Available Documents (Subject to Change)
Supplier
GGB Industries, der Erfinder der Picoprobe®-Produktlinie von Mikrowellen- und Oszilloskop-Tastköpfen, liefert bereits seit 1980 Messköpfe für On-wafer Messungen für die Halbleiterindustrie, beginnend mit einer Reihe hochohmiger Sonden für die Fehlersuche bei der Diagnose der internen Funktionsweise komplexer Logik- und Speicherchips. Seitdem hat GGB eine beeindruckende Anzahl an neuen, patentierten Lösungen entwickelt. Man kann also mit Fug und Recht behaupten, dass GGBs Stärken insbesondere handwerkliches Können, Präzision, Kundendienst und Problemlösung sind.
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