The Multiposition Wafer Probe combined with the RM3000+ Test Unit provides a high quality, easy to use system for measuring the sheet resistance and/or volume resistivity of wafers up to 200mm (8″) in diameter.
The Multiposition Wafer Probe has the ability to probe 1, 5, 9, or somewhat more positions on multiple wafers with 1mm positioning repeatability from wafer to wafer. It is not motorized, but requires that the user moves the wafer stage by hand. It is available with either a 6″ (150mm) wafer chuck or an 8″ (200mm) wafer chuck.
The price is the same for either unit, however, the MWP-6 would be preferable for use with wafers that are 6″ in diameter or smaller due to the increased ease of centering the wafer on the wafer chuck. Annular rings (not vacuum rings) allow wafers to be centered more easily. To aid in centering smaller wafers, the 6″ Multiposition Wafer Probe has circular patterns on the wafer chuck with diameters of 25mm, 50mm, 75mm, 100mm, and 125mm.
The 8″ system has circles at 125mm and 150mm. The Multiposition Wafer Probe can be connected to a vacuum source for wafer hold-down. The instrument comprises a white powder-paint coated metal base carrying a Delrin column supporting the vertical slide, operating lever shaft, and micro-switch. The vertical slide carries the probe head, secured by a clamp screw. The probe head is positioned so that the micro-switch does not pass current until the probes have made contact, lost motion ensures that the current is switched off before the probes are raised. The wafer table slides towards the operator to enable the wafer to be centrally positioned, after which the vacuum control valve can be operated to secure it in position. When the table is pushed to the limit of its travel, a measurement can be made at it’s center. Four radial positions at right-angles are denoted by a spring-loaded index ball incorporated in the rotary table. The radial distance of measurement is denoted by a similar arrangement on the linear slide index plate. Unwanted settings can be blocked off by easily removed screws. So that, for example, one could choose to measure at the center and four points at 50mm radius. A grounded metal shield screens the wafer from light and electrical noise during measurement. It is arranged that the shield rises when the probe head is fully lifted to permit loading.
The system incorporates the Jandel Cylindrical probe head which is built to high standards of quality and accuracy.
Multiposition Wafer Probe Specifications:
- Wafer Chuck – Hard anodized aluminum alloy with vacuum hold, centering grooves, and tweezer notch for: 6″ model – 3″, 4″, 5″ and 6″ wafers, 8″ model – 5″, 6″, and 8″ nominal diameters.
- 6″ Model Preset Measurement Postions: Center and four radii at right angles 15, 20, 25, 35, 50, and 60mm
- 8″ Model Preset Measurement Postions: Center and four radii at right angles 32, 38, 50, 57, 68, and 94mm
- Services: Vacuum line or pump required
- Dimensions: 355 x 215 x 195mm high
- Net weight: 6″ model – 3.5kg, 8″ model – 4.0kg
| Sampling Plan C, ASTM F-81-89, using MPW-8″ | ||
The RM3000+ Test Unit is a specialty electronics instrument designed specifically for the four point probe measurement. It features high accuracy, an excellent range, and many features which simplify the four point probing measurement. The following are features of the RM3000+ Test Unit:
- The sheet resistance range of the RM3000+ Test Unit is from 1 milliohm-per-square (10^-3) to 10^8 ohms-per-square with 0.3% accuracy. The volume resistivity range is from 1 milliohm-cm (10^-3) up to 10^6 ohms-cm, however, that resistivity range refers to measuring a bulk material directly as opposed to measuring a thin film and converting to volume resistivity using the software. For example, a thin layer of copper (1.68 x 10^-6 ohm-cm) up to about 16 microns thick can be measured. The RM3000+ can determine the volume resistivity value if one enters the film thickness.
- The RM3000+ includes PC control software which can be used for measurement logging (storing data in CSV format) and can save measured values as sheet resistance or volume resistivity.
- The RM3000+ display reads-out the input current as well as either ohms-per-square (sheet resistance), ohms-cm (volume resistivity), or millivolts, without requiring the use of the included PC software. The volume resistivity readout requires entering thickness for a wafer or thin film, or tip spacing if measuring a bulk sample.
- The RM3000+ has onboard non-volatile memory so that up to 50 measurements can be stored internally and then downloaded and saved all at one time using the software. Alternately, each measurement can be saved to a PC as it is made using the included software.
- The RM3000+ has an auto-range button that can be used to automatically determine the optimum input current for a given material without using the trial and error method.
- The RM3000+ has forward (FWD) and reverse (REV) buttons to reverse the direction of current flow. A common way to determine if a measurement is valid is to reverse the direction of current flow and then check to see if the forward and reverse voltage readings correlate well, i.e., the values should be similar, but with the reverse current voltage being a negative value.
- The RM3000+ allows the input of a correction factor for samples that need to be corrected for size.
- The RM3000+ has a date and time stamp feature
Superior Current Source
- 10nA to 100mA (99.999mA) current source selectable in steps to 3 decimal place resolution
- Current set numeric keypad
- 4 default preset current programs (user programmable)
Superior Inbuilt DVM
- Input Impedance 1,000,000,000,000 ohms
- Input Bias current 4pA
- DVM 1300mV range and 130mV range
- 130mV accuracy
- 0.2% +/- 5uV resolution (10uV or 1uV) range
- 1300mV accuracy 0.2%+/-100uV resolution
- 100uV Ohms/Square
- Rapid Zeroing null function for DVM
Features
- 28 Key high quality Keypad
- 16×2 line LCD Display for simultaneous indication of Set Current and either Ohms/Sq or mV
- Auto-Ranging capability to determine the optimum input current based upon the material being measured.
- Intuitive operation
- Microprocessor controlled
- Reduced Footprint
- Robust Attractive ABS Case
- Accurately measures down to 10’s of milliohms/square without external meter
- 4mm socket facility to connect an external meter
- RS232/USB connectivity for control and for collecting data in CSV format
- Automatic compliance voltage limit protects your sample which reduces maximum voltage as higher currents are set 5-40V
- Warning messages when compliance limit is reached, or DVM input exceeded
- Self test facility
- Flash upgradeable software
- CE Marked
- AD/DA converters and amplifiers for the DVM and setting the Current source and DVM, are Burr Brown 110V or 240V operation (selectable)
Downloads
We Recommend
If you do not require as great a measurement range as the RM3000+ Test Unit provides, you might be interested in the:
Multiposition Wafer Probe combined with the HM21 Hand Held Meter.
Four-Point-Probes is a division of Bridge Technology. To request further information please call Bridge Technology at (480) 219-9007 or send e-mail to Joshua Bridge at: sales@bridgetec.com
