4.4.2 Lifted Land Repair, Film Adhesive Method

Outline

This method is used to repair damaged and lifted lands. The lifted lands are repaired with dry film epoxy. They are re-bonded to the circuit board surface using a bonding press or bonding iron.

Caution: It is essential that the board surface be extremely smooth and flat. If the baseboard is damaged, see the appropriate procedure.

Minimum Skill Level - Advanced

Conformance Level - Medium

Tools and Materials

Bonding Film Dry film adhesive used to bond lifted lands, pads and conductors.

Bonding Iron Delivers the optimal heat for curing adhesive bonding film.

Bonding Tips Bonding Tips used to bond adehesive backed Circuit Frames.

Circuit Bonding System System to repair damaged conductors, BGA pads, and SMT pads.

Cleaner General purpose cleaner for removing contamination.

Flex-Rack PCB Holder Sturdy rack for PCBs used for rework and positioning.

High Temp Tape Discs High temperature polyimide tape discs, .50" diameter.

Knife with #16 Blades A must-have tool for precise cutting, scraping and trimming.

Microscope Precision microscope with stand and lighting for work and inspection.

Precision Tool Set Nine precision-crafted tools for detailed circuit board work.

Repair Skills Practice Kit Training kit to practice circuit board repair skills prior to testing for certification.

Scraper, Curved Tip Hardened stainless steel tip for scraping solder mask and removing defects.

Tweezers Multiple sizes and tip configurations of tweezers for various small parts handling needs.

Wipes Nonabrasive, low-linting wipes for cleanup.

Procedure

Procedure

1. Clean the area.
2. Remove any obstructions that prevent the lifted land from making contact with the base board material.
3. Use the Surgical Knife and scrape off any epoxy residue, contamination, or burned material from the board surface.
4. Clean the area.
5. Cut out a piece of bonding film that matches the area of the lifted land. Be careful not to contaminate the dry film epoxy with materials that could reduce the bond strength. (See Figure 1)
   Note: Dry film adhesive thickness should be selected to meet the requirements of the PC Board.
6. Place the dry film under the lifted land. (See Figure 1)
7. Place a piece of High-Temperature Tape over the lifted land and press the land down into contact with the adhesive film. (See Figure 2)
8. Select a bonding tip with a shape to match the shape of the lifted land.
   Note: The bonding tip should be as small as possible but should completely cover the entire surface of the new land.
9. Position the circuit board so that it is flat and stable. Gently place the hot bonding tip onto the tape covering the new land. Apply pressure as recommended in the manual of the repair system or repair kit for 5 seconds to tack the land in place. Carefully peel off the tape. 
10. Gently place the bonding tip directly onto the land. Apply pressure as recommended in the manual of the repair system or repair kit for an additional 30 seconds to fully bond the land. The bonding film is fully cured. Carefully clean the area and inspect the land.
    Note: Double-sided and multilayer circuit boards may require an eyelet to restore the through connection. Refer to section 5.0 Plated Hole Procedures.
11. Carefully remove any excess bonding film inside the plated hole using a ball mill or drill bit. Turn the ball mill or drill bit by hand to prevent damage to the wall of the plated-through hole.
12. Install the proper component and solder it in place. 
    Note: This method is used to repair a lifted land, but the repaired land may not have an intermetallic connection to the remaining plated hole. The solder joint of the replaced component will restore the integrity of the electrical connection, or an eyelet or buss wire may be used. See Plated Hole Repair Procedures.
13. Replace surface coating to match prior coating as required.

Evaluation

1. Visual examination and tape test per IPC-TM-650 test method 2.4.1. (ANCI/IPC-FC-250A)
2. Electrical tests as applicable.

Images

Lifted Land Repair, Film Adhesive Method

Cut out the appropriate shape of Bonding Film material to match the area of the lifted land.

Place Kapton tape over the lifted land.