CDM ESD Test System

1. Basic Understanding of the Equipment

1.1 Product Overview

The ESD-CDM (Charged Device Model) CDM ESD Test System is a high-precision immunity test instrument specifically designed for “charged device contact discharge” scenarios involving semiconductor devices during production, transportation, and assembly. Its core function is to simulate the transient discharge process that occurs when a semiconductor device—which has become charged (e.g., through triboelectric charging or induced charging)—comes into contact with a grounded object. By precisely controlling parameters such as discharge voltage and current waveforms, it evaluates the device’s tolerance to this type of “latent electrostatic shocks,” enabling the early detection of risks such as internal circuit burnout and functional failure. It provides a testing basis for the reliability design, mass production quality inspection, and international compliance certification of semiconductor devices.

This system features an integrated “charge injection–contact discharge” design and is equipped with a high-precision charge measurement module, with a discharge voltage error of ≤±3%; It is compatible with fixtures for mainstream semiconductor packages such as DIP, SOP, QFP, and BGA. Equipped with a touchscreen display in both Chinese and English, it supports one-click configuration of test parameters, automated control of the discharge process, and real-time storage of test data, meeting the semiconductor industry’s requirements for high precision and high compatibility in testing.

1.2 Applicable Standards

This equipment fully complies with the following domestic and international CDM electrostatic discharge testing standards:

Standard Number	Standard Title
ANSI/ESDA/JEDEC JS-002-2014	Electrostatic Discharge (ESD) Sensitivity Testing—Charged-Device Model (CDM)—Component Level
IEC 60749-28:2022	Semiconductor Devices—Mechanical and Climatic Test Methods—Part 28: Electrostatic Discharge (ESD) Sensitivity Testing—Charged-Device Model (CDM)
AEC-Q100-011	Charged Device Model (CDM) Electrostatic Discharge Test
EIA/JESD22-C101	Test Method for Electrostatic Discharge Sensitivity Testing—Charged-Device Model (CDM)
ANSI/ESDS 5.3.1-2009	Electrostatic Discharge Sensitivity Testing – Charged Device Model (CDM) – Component Level
JEITA ED-4701/300 Test Method 305	Charged Device Model Electrostatic Discharge (CDM/ESD)
GB/T 4937.28-2024	Semiconductor Devices—Mechanical and Climatic Test Methods—Part 28: Electrostatic Discharge Sensitivity Testing—Charged Device Models (Equivalent to IEC 60749-28:2022)

1.3 Principles of the CDM Discharge Model

The Charged Device Model (CDM) simulates the physical process by which a semiconductor device accumulates static electric charge and then discharges it through contact between its pins and a grounded conductor. The device becomes charged through an induced high-voltage electric field, and when the device’s pins come into contact with a ground probe, the stored charge is rapidly discharged within nanoseconds, forming a discharge current pulse with a high peak and a fast rising edge. This pulse exerts a stress on the device’s internal gate oxide layer and metal interconnects, thereby evaluating the device’s electrostatic discharge (ESD) tolerance.

2. Safety Precautions

2.1 Work Environment Requirements

Operating temperature: 15°C to 35°C; operating relative humidity: 30% to 60%. Do not use in environments with high humidity or condensation to prevent high-voltage arcing.

There must be no strong electromagnetic interference, no sources of vibration, no flammable or explosive materials, and no corrosive gases in the surrounding area.

Place it on a stable work surface; avoid tilting or inverting it, and keep it away from sources of vibration.

The distance between the equipment and walls or surrounding structures (such as other test equipment or shelving) must be at least 500 mm to facilitate maintenance; at least 1000 mm of space must be left in front of the equipment to ensure smooth operation, with no obstructions in the surrounding area.

2.2 High-Voltage Safety Standards

2.2.1 Security Check

Verify that the power supply is compatible with the equipment, ensure that the power supply is properly grounded, and check that the grounding wire is free of damage or looseness;

Grounding Requirements: The host unit’s protective grounding terminal (PGND) must be connected to ground; the grounding resistance must be ≤4Ω; the grounding cable must be securely connected, with no looseness or breaks.

2.2.2 Safety Requirements for Operational Procedures

Operators must undergo professional training and be familiar with this manual and the relevant standards. Non-professionals are prohibited from operating or disassembling the equipment. The equipment contains high-voltage circuits; opening the cover may pose an electric shock hazard. Contact the manufacturer’s technical staff for repairs;

Once the equipment is powered on, do not touch the test bench, high-voltage cables, discharge probes, or other related components to prevent electric shock;

Operators should ensure their hands are dry and free of metal jewelry; it is recommended that they wear insulated gloves while working;

Do not eat or drink during the test to prevent accidents caused by electric shock;

When multiple people are involved, clearly define roles and responsibilities, and confirm them with each other before starting the test to avoid errors.

2.3 Equipment Safety Standards

Before connecting or disconnecting high-voltage cables, you must turn off the main unit’s power and wait at least 5 minutes to ensure that the internal capacitors are completely discharged;

When inserting a high-voltage plug into an outlet, align it with the positioning pins. Never force the plug into the outlet if it is not properly aligned, to avoid damaging the internal copper pins;

If you discover damage to high-voltage cables or loose connectors, stop using the product immediately and contact customer service to have them replaced;

Do not suddenly cut off the power or unplug or plug in the high-voltage connector while the equipment is running, to avoid damaging the high-voltage module;

Do not scratch the touchscreen with hard objects, and do not press the screen with sharp objects;

Avoid bumping the equipment during testing to prevent the device under test from shifting, which could cause the test to fail or damage the probes.

2.4 Other

For matters not covered in this manual, please proceed with caution or contact us.

3. Equipment Overview and Wiring

3.1 Front View

See Figure 3-1.

Number	Note
Electrostatic Discharge Simulator
①	Touchscreen
②	High-Voltage Indicator Light
③	High-voltage connection. Lift the positioning pin, align the groove in the discharge tower’s high-voltage plug with the positioning pin, and slowly insert it all the way to the bottom. Then lower the positioning pin to lock the high-voltage plug in place.
CDM Electrostatic Discharge Tower
④	Probe lift frame; the probe mounting location is directly opposite the test bench, as shown in Figure 3-2.
⑤	Standard test stand, adjustable for both position and height
⑥	BNC connector; use a coaxial cable to connect to an oscilloscope to view the output waveform. Note: Make sure the oscilloscope has a sufficient range, or use an attenuator to prevent damage to the oscilloscope.

3.2 Rear View

See Figure 3-3.

Number	Note
Electrostatic Discharge Simulator
①	Power cord receptacle (with fuse) for connecting the device to an appropriate power source
②	Power Switch
③	PGND: Protective ground terminal; connect to earth using a ground wire.
④	Connecting the Signal Cables to the Discharge Tower
⑤	USB port: Can be used to connect a USB mouse to control the touchscreen, or to connect a USB flash drive to update the software.
⑥	LAN port, spare
CDM Electrostatic Discharge Tower
⑦	Grounding busbar: Connect the ground wire from the probe lifting frame to the grounding busbar, and then use a wire to connect the grounding busbar to the protective grounding terminal on the back of the Electrostatic Discharge Simulator.
⑧	High-Voltage Line Connection
⑨	Signal Line Connections
⑩	Connect the test bench ground wire to the protective ground terminal on the back of the Electrostatic Discharge Simulator.
⑪	High-Voltage Cable Connections on the Test Stand

3.3 Replacing the Discharge Tower

This Electrostatic Discharge Simulator can be connected to discharge towers used for various tests. If you need to replace the discharge tower for testing, please follow the operating procedures below strictly.

Instructions	Note
①	Verify that the Electrostatic Discharge Simulator is in the “Test Stopped” state, then shut it down.
②	Disconnect all cables connecting the original discharge tower to the Electrostatic Discharge Simulator.
③	Connect all the cables between the new discharge tower and the Electrostatic Discharge Simulator.
④	Turn on the computer and run the new test.

4. Introduction to the Touchscreen Program

4.1 Initial Screen

See Figure 4-1.

Number	Note
①	When the CDM discharge tower is connected to the host, “CDM Available” will be displayed; click it to enter the CDM test interface.
②	Switch Between Chinese and English
③	Product Information Page

4.2 CDM Test Interface

See Figure 4-2.

Number	Note
①	The test voltage and polarity can be set
②	If you want to run a single test, select “Single Test.”
③	If you want to run continuous testing, select “Continuous Testing.”
④	You can set the number of tests; only consecutive tests are allowed.
⑤	Start/Stop Test
⑥	Return to the Home Screen

5. CDM Electrostatic Discharge Testing

5.1 Preliminary Commissioning of the Test Bench Location

5.1.1 Placement Requirements for the Device Under Test

Operators should wear antistatic wristbands and antistatic clothing to prevent static electricity from the human body from damaging the devices under test; place the semiconductor devices under test with their pins facing upward in the center of the isolation plate,

5.1.2 Test Bench Commissioning

First, disconnect the high-voltage connection cables and place them on an insulated work surface. Then, refer to Section 4.2 to begin the test. Lower the probe at the standard speed. Based on the probe’s position as it descends, adjust the test stand’s height and horizontal alignment so that the probe makes just enough contact with the target pin upon reaching the bottom. Observe the contact status to avoid damaging the device pins due to excessive pressure. Once the adjustments are complete, stop the test and reconnect the high-voltage cable.

5.2 Recommended Standard Test Parameters

In accordance with the ANSI/ESDA/JEDEC JS-002-2014 standard, the recommended parameters for routine testing are as follows: Discharge voltage: Select based on device class—Class 0 (<250 V), Class 1 (250 V to <500 V), Class 2 (500 V to <1000 V), Class 3 (≥1000 V); Discharge polarity: Test once for both positive and negative polarities; Number of discharges: At least 3 discharges per pin.

5.3 Start/Stop Test

Set the test parameters as described in Sections 4.2 and 5.2, and start the test. If any abnormalities occur during the test, press the stop button to halt the test, make the necessary adjustments, and try again. After the test is complete, ensure that any internal residual charge is completely discharged, and remove the device under test. If the equipment will not be used again that day, you may turn it off.

5.4 Interpretation of Test Results

All standards follow a unified testing and evaluation logic:

Number	Note
Benchmarking	Before the CDM discharges, measure all parameters under the conditions specified in the standard and record the reference values.
Discharge Test	Perform CDM discharges at the specified voltage, polarity, and number of cycles as required by the standard
Comparison of Retest Results	After discharge, remeasure all parameters under conditions identical to those used for the baseline test.
Failure Determination	If any parameter exceeds the specifications, the device malfunctions, or there is physical damage, the device under test is deemed to have failed.
Level Confirmation	The highest voltage at which none of the samples failed shall be used as the final CDM withstand rating for the device under test.

6. Daily Maintenance and Care of Equipment

6.1 Daily Cleaning and Maintenance

After each test, use a clean, soft cloth to wipe dust from the main unit’s exterior, the touchscreen, and the surface of the discharge tower to keep the equipment clean; use a dedicated screen-cleaning cloth to clean the touchscreen. Do not use organic solvents such as acetone, and do not spray water directly onto the screen to clean it; Clean dust and foreign objects from the surfaces of the test bench, sensing plate, and isolation plate weekly to ensure good insulation performance; if the probe tip is soiled, gently wipe it with a lint-free cotton swab dipped in a small amount of anhydrous ethanol, and allow it to air dry before use.

The probe can be unplugged directly for cleaning or replacement; see Figure 6-1.

6.2 Items for Periodic Inspection

6.2.1 Electrical Connection Inspection

Inspection Frequency: Once a month; Inspection Items: Check power cords, high-voltage cables, grounding wires, and communication cable connectors for looseness, oxidation, or damage; Remedial Actions: Tighten any loose connectors immediately; gently sand off any oxidation with fine-grit sandpaper; and replace any damaged cables immediately.

6.2.2 Mechanical Structure Inspection

Inspection Frequency: Once a month; Inspection Items: Check whether the test bench adjustment knobs turn smoothly, whether the probe bracket stop blocks are secure, and whether the probe extends and retracts normally; Remedial Actions: Apply a small amount of silicone grease to the adjustment mechanism for lubrication; replace the probe if it is deformed or worn.

6.3 Long-Term Storage Requirements

Before long-term storage, clean the entire surface of the unit and unplug all external cables; cover the unit with a dust cover and store it in a dry, well-ventilated environment free of corrosive gases; the storage environment should have a temperature of 0°C to 40°C and a relative humidity of ≤70%, and direct sunlight should be avoided; Every 3 months, power on the device and leave it in standby mode for 30 minutes to remove moisture and protect the high-voltage modules.

6.4 Calibration Interval Requirements

To ensure the measurement accuracy and operational reliability of the equipment, it is recommended that it be sent periodically to a qualified third-party metrology laboratory for calibration. The recommended calibration interval is 12 months. Users may determine the specific calibration interval based on frequency of use, environmental conditions, and quality system requirements.

7. Troubleshooting and Resolving Common Problems

7.1 Power-Related Faults

Fault Symptoms	Possible Causes	Procedure
No display when powered on; power indicator light does not turn on	The power cord is not plugged in securely; the fuse has blown.	Check the power cord connections; replace the fuse with one of the same rating after turning off the power.
Touchscreen Not Responding	There are stains on the screen, and the system is malfunctioning.	Clean the screen surface; restart the device

7.2 High-Voltage Faults

Fault Symptoms	Possible Causes	Procedure
High voltage cannot be applied after clicking “Start.”	High-voltage cables not properly connected, poor grounding, and dirt on the test bench surface	After turning off the power, unplug and replug the high-voltage cables, then tighten them; check and secure the ground wire; clean the surface of the test bench.

7.3 Operational Faults

Fault Symptoms	Possible Causes	Procedure
Discharge cycles are not counted	The probe is not in contact with the device	Recalibrate the position to ensure good contact.
Communication error; the discharge tower is not operating	Loose communication cable	Tighten the signal cable connections after power is turned off

7.4 Waveform Anomalies

Fault Symptoms	Possible Causes	Procedure
The waveform peak is too low	Poor probe contact, voltage set too low	Clean the probe tip and adjust the contact pressure; verify and increase the set voltage.
The rising edge of the waveform does not meet specifications	Probe wear, excessive ground loop impedance	Replace the test probe; check the ground wire and reduce the ground resistance.
Many waveform artifacts	Electromagnetic Interference from the Surroundings	Eliminate sources of interference and use shielded cables