CDE ResMap 178 four-point probe mapper

Where the ResMap 178 fits

The CDE ResMap 178 is a bench-top four-point probe that maps sheet resistance across a whole wafer. In a research cleanroom or small fab it sits downstream of the implanter, the diffusion furnace and the metal deposition tools. It answers whether the implant dose landed, whether the diffusion is uniform from wafer centre to edge, and whether a sputtered or evaporated metal film has the expected thickness and resistivity.

The 178 is a manually loaded model. You place the wafer, choose a recipe and the tool steps the probe through the map. Used ResMap 178 units are attractive for labs that need full-wafer maps without the footprint of an automated cassette system. Because it measures electrically rather than optically, it complements thickness tools such as a reflectometer.

What we inspect on a used ResMap

The probe head is where most problems start, so we look at it first.

• Probe tips. Wear, contamination and tip spacing under the microscope. Worn or contaminated tips cause contact noise and scattered readings.
• Probe force and Z motion. Smooth landing, consistent force and no bounce. Hard landings damage soft films and wear tips early.
• Electronics. Current source and voltmeter accuracy checked against reference resistors, and the full range of currents.
• Stage and chuck. Travel on all axes, homing, vacuum hold-down and wafer centring.
• Reference measurements. We measure sheet resistance standards and repeat a map to check repeatability.
• PC and software. Operating system, recipe library, map export and the interface to the controller.

Refurbishment scope

A typical refurbishment replaces or reconditions the probe head, cleans and adjusts the stage drive, checks and replaces cables and connectors in the measurement path, and recalibrates the electronics. We rebuild the recipe set for your wafer sizes and film types, and then run reference maps for the report. Probe heads are consumables: tip life depends on force, film hardness and how many sites you measure, so we include a view on spare heads in our quote.

Upgrades and spare parts

The ResMap is a simple tool, and most upgrades are about matching it to your films and keeping data accessible. Labs that measure both implants and thin metals often run two heads and swap them by film type. Older PCs and data formats are the main risk, and we move the software to supported hardware where the licence and interface allow. Probe heads, chucks, cables and reference standards are available through spare parts, and periodic checks against standards are part of our calibration service.

Facilities

• Single-phase mains power for the unit and PC
• Vacuum for the wafer chuck
• A stable bench with space for the PC and wafer handling
• Electrically quiet location; avoid sharing a circuit with large pumps or heaters

Buying advice

List your film types and their sheet resistance range before choosing heads. A head that works well on implanted silicon may damage a 20 nm metal film, and the opposite combination gives unstable contact. Ask which heads come with the tool, their condition and when they were last calibrated. If you need cassette loading for production volumes, a manual 178 is not the right model. For cassette-fed mapping or optical film measurement, see the other tools in our metrology and inspection range.