Printed circuit board and manufacturing method thereof

A printed circuit board comprising:

• an insulating layer;
• a metal seed layer formed on the insulating layer;
• a metal pad formed on the metal seed layer;
• a surface treatment layer formed on the metal pad and the metal seed layer;
• a solder layer formed on the surface treatment layer of the metal pad and the surface treatment layer of the metal seed layer;
• and
• an intermetallic compound layer formed between the solder layer and the surface treatment layer.

A manufacturing method of a printed circuit board comprising:

• forming a metal pad on an insulating layer;
• forming a surface treatment layer on the metal pad;
• forming a solder layer on the surface treatment layer and the insulating layer;
• and
• forming an intermetallic compound layer between the solder layer and the surface treatment layer.

A manufacturing method of a printed circuit board comprising:

• forming a metal seed layer on an insulating layer;
• forming a metal pad on the metal seed layer;
• forming a surface treatment layer on the metal pad and the metal seed layer;
• forming a solder layer on the surface treatment layer of the metal pad and the surface treatment layer of the metal seed layer;
• and
• forming an intermetallic compound layer between the solder layer and the surface treatment layer.