What is Lifted Land
In the PCB industry, “lifted land” refers to a condition where the conductive area on a circuit board surface, known as a land, becomes detached or lifted from the base material. This detachment can occur partially or fully, and it may or may not involve the lifting of any resin along with the land. The lifting of a land can be caused by various factors, such as mechanical stress, thermal stress, or improper handling during assembly or rework processes.
When a land is lifted, it can lead to significant issues in the functionality and reliability of the circuit board. The electrical connection between the component and the board may be compromised, resulting in failures or malfunctions. To address this problem, repair techniques can be employed. One such method involves using a dry film epoxy adhesive to bond the lifted land back in place. The adhesive film is cut to match the area of the lifted land and placed underneath it. A high-temperature tape is then applied over the land and pressed down to ensure contact with the adhesive film. Heat and pressure are applied using a bonding iron with a tip that matches the shape of the lifted land, effectively reattaching it to the base material.
The repaired land may not have an intermetallic connection to the remaining plated hole. Therefore, the integrity of the electrical connection is restored through the solder joint of the replaced component or by using additional components like eyelets or buss wires. The evaluation of the repaired land can be done through visual examination and tape testing according to the IPC-TM-650 test method 2.4.1.