Method of forming redistribution pad and method of manufacturing semiconductor package

A method of forming a redistribution pad, the method comprising:

• forming a hole exposing a redistribution pattern in a redistribution insulating layer;
• forming a photoresist composition on a surface of the redistribution insulating layer and filling the hole, the photoresist composition including at least one first photoinitiator and at least one first crosslinking agent that cause a crosslinking reaction by a first light and at least one second photoinitiator and at least one second crosslinking agent that cause a crosslinking reaction by a second light having a different wavelength from the first light;
• irradiating the first light to the photoresist composition;
• forming a photoresist pattern having a pattern hole using the photoresist composition to which the first light is irradiated;
• forming a first metal layer on the redistribution pattern using the photoresist pattern, wherein the first metal layer constitutes a first portion of the redistribution pad;
• irradiating the second light to the photoresist pattern;
• and
• forming a second metal layer and a third metal layer on the first metal layer using the photoresist pattern to which the second light is irradiated, wherein the second metal layer and the third metal layer constitute a second portion of the redistribution pad.

A method of forming a redistribution pad, the method comprising:

• forming a hole exposing a redistribution pattern in a redistribution insulating layer;
• forming a seed layer covering a surface of the redistribution insulating layer and a surface of the redistribution pattern exposed by the hole;
• forming, on the seed layer, a photoresist composition including at least one first photoinitiator and at least one first crosslinking agent that cause a crosslinking reaction by a first light having a wavelength in a range from 355 nm to 375 nm, and at least one second photoinitiator and at least one second crosslinking agent that cause a crosslinking reaction by a second light having a wavelength in a range from 390 nm to 450 nm;
• irradiating the first light to the photoresist composition;
• forming a photoresist pattern having a pattern hole using the photoresist composition to which the first light is irradiated;
• irradiating the second light to the photoresist pattern;
• and
• forming the redistribution pad using the photoresist pattern to which the second light is irradiated, wherein the redistribution pad includes a first metal layer including copper, a second metal layer including nickel, and a third metal layer including gold.