Types of Cross Section (1)

Substrate sectioning can be classified into three types based on the mold type, sectioning purpose, etc.

 

Let's explore this and also look into p-lab as a side note.

 

1. Point Section

A point section involves sectioning only up to a specific point. For example, it's often used to observe defects caused by foreign particles, such as bump defects or pinhole defects, on the substrate.

 

The mold for a point section has a semi-circular shape when viewed from above. While the other sectioning methods explained later might accommodate multiple substrates at once, a point section only accommodates one. This single substrate is attached vertically to the flat side of the semi-circular mold. Afterward, mold compound is poured, ensuring that no compound gets between the flat side and the substrate to avoid trapping air bubbles. In essence, the mold compound only secures the substrate through the force of adhesion, without entering between them. Even after this step, it's necessary to use a needle to remove any bubbles.

 

There is flexibility in how to section this point section mold, but starting from the top is recommended. This not only smooths out the uneven top surface for better observation but also allows for easier sectioning while observing the point area.