Method for manufacturing light-emitting element and light-emitting device using photolithography technique

A method for manufacturing a light-emitting element, the method comprising:

• forming a first electrode over an insulating surface;
• forming an organic compound layer over the first electrode, the organic compound layer comprising a light-emitting layer and an electron-injection layer over the light-emitting layer;
• forming a sacrificial layer over the electron-injection layer;
• forming a resist mask over the sacrificial layer;
• processing the sacrificial layer into an island shape using the resist mask;
• processing the organic compound layer into an island shape using the sacrificial layer having the island shape as a mask;
• removing part of the sacrificial layer having the island shape with an acidic chemical solution to expose a top surface of the electron-injection layer;
• and
• forming a second electrode over the electron-injection layer,
• wherein the electron-injection layer comprises an organic compound having a basic skeleton and an acid dissociation constant pKa of greater than or equal to 1.

A method for manufacturing a light-emitting device, the method comprising:

• forming a first pixel electrode and a second pixel electrode over an insulating surface;
• forming a first organic compound layer over the first pixel electrode and the second pixel electrode, the first organic compound layer comprising a first light-emitting layer and a first electron-injection layer over the first light-emitting layer;
• forming a first sacrificial layer over the first electron-injection layer;
• processing the first organic compound layer and the first sacrificial layer into an island shape covering the first pixel electrode by a photolithography technique;
• forming a second organic compound layer over the first sacrificial layer having the island shape and the second pixel electrode, the second organic compound layer comprising a second light-emitting layer and a second electron-injection layer over the second light-emitting layer;
• forming a second sacrificial layer over the second electron-injection layer;
• processing the second organic compound layer and the second sacrificial layer into an island shape covering the second pixel electrode by the photolithography;
• removing part of the first sacrificial layer having the island shape and part of the second sacrificial layer having the island shape with an acidic chemical solution to expose a top surface of the first electron-injection layer and a top surface of the second electron-injection layer;
• and
• forming a common electrode over the first electron-injection layer and the second electron-injection layer,
• wherein each of the first electron-injection layer and the second electron-injection layer comprises an organic compound having a basic skeleton and an acid dissociation constant pKa of greater than or equal to 1.