What are the recommended rework and removal procedures for the Sona IF573 module?

Sona IF573

Answer

Question

What is the proper procedure for removing or reworking a Sona IF573 (453-00117 or 453-00118) surface-mount module on a PCBA without causing thermal damage or board delamination?

Answer

To safely remove or replace a Sona IF573 surface-mount module during manufacturing or repair, follow these mandatory rework guidelines:

1. Pre-Bake the PCBA

Bake the entire PCBA assembly at 125C for 48 hours prior to applying rework temperatures.

  • Purpose: Removes absorbed ambient moisture from the PCB substrate and module to prevent moisture expansion, internal delamination, or package "popcorning."

2. Mask the Shield Can

Apply a strip of high-temperature polyimide tape (e.g., Kapton tape) directly over the metal shield of the IF573 module.

  • Purpose: Acts as a thermal barrier to deflect direct top-side heat away from sensitive internal components (SoC, PMIC, crystal oscillator) and prevents thermal oxidation or discoloration of the metal shield finish.

3. Pre-Heat the Carrier Board (Crucial)

Place the PCBA assembly on a bottom-side IR preheater or hot plate set between 100C and 120C for 3 to 4 minutes.

  • Purpose: Brings the board and ground planes up to temperature from below, drastically reducing the amount of top-side hot air required to melt the ground pads and perimeter castellated solder joints.

4. Controlled Top-Side Hot-Air Application

Apply top-side hot air set between 300C and 350C, focusing airflow along the outer perimeter ground pads and castellated pins rather than the center of the shield.

Critical Limit: The active top-side hot-air reflow phase must take less than 20 seconds to safely lift or align the module.

What Happens If Proper Rework Procedures Are Skipped?

Skipping the pre-bake or bottom-side preheating step forces technicians to over-apply top-side hot air. This can cause:

  • Thermal Oxidation: Shield metal turning an orange/copper color due to cuprous oxide formation.

  • Internal Component Damage: Unintended re-melting of internal solder joints, component tombstoning, or frequency drift in the reference crystal oscillator.

  • PCB Delamination: Permanent thermal shock to the host PCB or module substrate.