How can wafer handling robots be incorporated into airflow verification?

The wafer handling robot is responsible for picking up, transporting and placing wafers inside the equipment. As it moves, the arms, gripper, and wafer itself all change local airflow. Airflow conditions measured in a stationary state cannot fully describe the protective effect during exercise.

Including the robot into airflow verification requires designing a test plan based on the actual trajectory, speed, dwell position and clamping state. The following will start from the following links: motion program, key postures, sampling arrangement and data association.

Define the robot’s motion program

Before verification, the robot’s motion program should be clarified:

• Movement trajectories and paths;

• Movement speed of each segment;

• Stay location and time;

• The sequence of actions for taking and releasing films;

• Cooperation with other agencies.

Different programs may create different airflow conditions. Verification should cover the actual production version of the program, rather than just testing a convenient gesture. After program changes, the original verification results may no longer be applicable and should be re-confirmed.

Pay attention to the obstruction of the air supply by the mechanical arm

When the robotic arm extends, rotates, and returns, it may block the air supply surface or change the direction of the airflow. The wafer may be in a weak protection zone as it passes through these locations.

Postures to watch for include:

• Extend your arms to their furthest position;

• The arm passes over or to the side of the wafer;

• The arm returns quickly;

• The clamping state of picking up and releasing the film;

• The gesture of waiting and staying.

For the occlusion and wake of the robotic arm, please refer to How will operating the arm interfere with the air supply to the workbench? , although the objects are different, the mechanisms of airflow obstruction are similar.

Wake and transient disturbances

When the robot moves rapidly, it will drive the surrounding air to form a wake. Wakes can draw background air into the wafer path or carry particles to sensitive locations.

When verifying, you should observe:

• Airflow changes during rapid movement;

• Whether the wafer passing position is affected by wake flow;

• Whether airflow is restored after exercise stops;

• Whether there are repeated disturbances.

The effect of wake is more obvious in open or semi-open areas. For the judgment method of air supply vortex and instantaneous disturbance, please refer to How does supply air vortex affect open workstations?。

The sampling arrangement must not hinder the robot's movements

When verifying sampling, the probe position should not impede robot movement or introduce new risks of collision or leakage.

Sampling layout should consider:

• Whether the probe position is within the robot's motion path;

• Is the fixing method safe?

• Whether the sampling tube affects the movement of the robotic arm;

• Whether sampling changes local airflow.

The location of the sampling point should cover the actual location where the wafer passes, rather than just under the air supply port. Related methods can be found in Why can’t the sampling point be located just below the air supply outlet? , please refer to the height selection How does a change in working height affect the detection position?。

Data should be associated with exercise periods

The verification data should correspond to the robot motion state. The record should include:

• exercise program version;

• The time of each action;

• The time point corresponding to the particle data;

• Simultaneous recording of airflow observations;

• The specific location where the exception occurred.

By correlating the data with movement periods, it is possible to determine in which movement phase the particle elevation occurred. For the method of observing process equipment in stages, please refer to What should I do if the cleanliness of the process equipment drops after it is started?。

Override normal and allowed exception states

Validation should not only cover normal operation, but also allowable exception states:

• Pause and wait;

• human intervention;

• Program switching;

• Resumes after a short downtime.

Airflow and protection during these conditions may differ from normal operation. There should be clear requirements for the processing procedures under abnormal conditions, rather than temporary decisions on site.

Coordination with airflow inside equipment

Robot movement is part of the airflow inside the device. Local air supply and overall machine airflow need to be coordinated:

• Whether the robot's movement area is within the air supply coverage;

• Whether the local air supply is affected by the robot's movements;

• Whether the return air path supports air discharge;

• Whether it is necessary to adjust the air supply according to the movement status.

The internal airflow organization of the equipment can be referred to How to plan clean air supply for closed equipment cavities? , understand the impact of paths and openings. When it comes to EFEM internal transmission, please refer to How does EFEM internal clean protection cover the wafer transfer path? , learn about path protection methods.

Project judgment example

The airflow of a certain equipment robot is acceptable when it is stationary, but occasional particles occur on the wafer when it is moving. The investigation found that the air supply was blocked when the arms were extended, and the wafer was in a weak protection zone when passing through the middle position. Adjustment method: Adjust the air supply direction so that the wafer path is always covered during movement. Adjusted dynamic grain reduction.

Another project created a wake when a robot returned quickly. Adjustment method: adjust movement speed and timing, add local diversion structure, and re-verify. After adjustment, the influence of wake flow is weakened.

These two situations illustrate that the airflow verification of the wafer handling robot needs to cover the actual movement process and cannot only measure the static state.

Key points for selection and acceptance inspection

Aili industrial equipment supporting support

The airflow verification of the wafer handling robot needs to cover the actual movement trajectory, occlusion changes and wake effects. Aili Industrial has collaborative capabilities in fans, motors, filters, control systems and complete machine assembly links. It can check the air supply direction, local protection range and operation settings based on the robot motion program, wafer path and equipment space, helping to extend the airflow verification from a static state to the actual movement process, rather than just measuring a convenient posture.