Circuit board, manufacturing method thereof, and electronic component package including the same

An electronic component package comprising:

• a first circuit board;
• a second circuit board connected to the first circuit board;
• and
• an electronic component mounted on one surface of the second circuit board,
• wherein the first circuit board comprises:
• an insulating layer;
• a contact layer that is disposed on a first surface of the insulating layer;
• a connecting layer that includes a connecting portion embedded in the insulating layer and disposed on the contact layer;
• a via layer that penetrates the insulating layer and is connected to the connecting layer;
• and
• a wiring layer that is disposed on a second surface of the insulating layer opposing the first surface and connected to the via layer,
• wherein the connecting portion includes a first connecting layer portion disposed on the contact layer and a second connecting layer portion disposed on the first connecting layer portion,
• the insulating layer includes a first portion disposed to embed the first connecting layer portion and surround the first connecting layer portion and a second portion to embed the second connecting layer portion,
• the insulating layer includes a cavity penetrating the second portion, and
• the first portion has a smaller area than the second portion.

A circuit board manufacturing method comprising:

• forming a first connecting layer portion and a first sacrificial layer;
• forming a second connecting layer portion on a first surface of the first connecting layer portion;
• forming a second sacrificial layer on the first sacrificial layer to have a smaller area than the first sacrificial layer;
• forming an insulating layer to embed the first connecting layer portion, the second connecting layer portion, the first sacrificial layer, and the second sacrificial layer;
• forming a via layer through the insulating layer to be connected to the second connecting layer portion;
• forming a contact layer on a second surface of the first connecting layer portion opposing the first surface;
• and
• removing the first sacrificial layer and the second sacrificial layer by etching the first sacrificial layer and the second sacrificial layer.