Hitachi CMI700 SRP-4 Probe

SRP-4 probe Core Technology

Four-Electrode Ring Array Design

The probe utilizes four independent electrodes arranged in a 90-degree ring. By alternating between applying excitation signals and receiving induced currents, it eliminates measurement errors introduced by traditional two-electrode methods due to contact resistance and edge effects. When inspecting tiny 0.5mm×0.5mm pads, this design reduces repeatability from ±0.1μm to ±0.02μm, meeting the stringent copper thickness consistency requirements of HDI (High Density Interconnect) boards.

High-Frequency Electromagnetic Coupling and Non-Contact Measurement

Based on the principle of electromagnetic wave penetration in a tunable frequency range of 1MHz to 100MHz, the probe performs inspections without physical contact with the circuit board surface, eliminating the risk of secondary contamination caused by traditional probes, such as scratches on the copper foil and residual metal debris. In use on a server motherboard production line, this technology has increased the copper surface cleanliness pass rate from 92% to 99.8%, reducing short-circuit failures caused by impurities by 80%.

Multi-physics fusion algorithm

Integrated dynamic compensation model for conductivity, thickness, and temperature. By real-time monitoring of ambient temperature (±0.1°C accuracy) and copper foil conductivity (±1% error), the system automatically corrects for the effects of thermal expansion and contraction (±0.05μm/10°C) and material batch variations on measurement results. The system maintains ±0.03μm detection accuracy across a wide temperature range of -20°C to 80°C, making it suitable for both cleanroom and standard workshop environments.

Hitachi Srp-4 Probe Core Functions and Performance Advantages

Submicron Accuracy and Wide Measurement Range Compatibility

Detection accuracy: ±0.03μm (under standard test conditions), capable of detecting thickness fluctuations of ultra-thin copper layers as thin as 0.5μm.

Measurement range: 0.5μm to 5mm, covering diverse requirements from flexible printed circuits (FPCs) to thick copper power boards (such as IGBT module substrates). Resolution: 0.01μm, enabling precise capture of copper thickness gradients (such as the gradient layer in the electroless copper deposition process).

High-speed dynamic detection and real-time feedback

Detection speed: Single-point measurement takes ≤30ms, supporting continuous detection at production line speeds (≥200mm/s).

Data output: Synchronously outputs three parameters: copper thickness, resistivity, and temperature compensation coefficient, providing multi-dimensional data support for process optimization.

Defect warning: Built-in threshold comparison function automatically triggers an alarm when copper thickness exceeds the design tolerance (e.g., ±10%), reducing the flow of defective products to the next process.

Industrial-grade environmental adaptability and stability

Protection level: The probe body meets IP65 protection standards and has an electromagnetic interference (EMI) resistance of ≥150V/m, making it suitable for strong electric field environments (such as near SMT patch lines).

Material compatibility: Supports detection of various materials, including pure copper (Cu), copper alloys (e.g., C194, KFC), and electroless copper. Calibration cycle: Using laser interferometer calibration technology, a single calibration is valid for up to 6 months, reducing maintenance costs.

Surface Cooper Srp-4 Probe data:

Chemical cooper：10 μin – 500 μin (0.25 μm – 12.7 μm)

electroplating cooper：0.1 mil – 6 mil (2.5 μm – 152 μm)

lind with range：8 mil – 250 mil (203 μm – 6350 μm)

accuracy：±1% (±0.1 μm) according to standard plate

Accuracy of Hitachi SRP-4 probe:

chemical cooper：standard deviation 0.2 %；

electroplating cooper：standard deviation 0.5 %

resolution：0.01 mils ≥ 1 mil, 0.001 mils <1 mil,

0.1 μm ≥ 10 μm, 0.01 μm < 10 μm, 0.001 μm < 1 μm

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