Method for manufacturing display device, display device, display module, and electronic device

A method for manufacturing a display device, comprising:

• forming an insulating layer;
• forming a conductive film over the insulating layer;
• forming a first hole-injection layer over the conductive film;
• forming a first hole-transport layer over the first hole-injection layer;
• forming a first light-emitting layer over the first hole-transport layer;
• forming a first electron-transport layer over the first light-emitting layer;
• forming a first sacrificial layer over the first electron-transport layer;
• processing the first hole-injection layer, the first hole-transport layer, the first light-emitting layer, the first electron-transport layer, and the first sacrificial layer to expose part of the conductive film;
• forming a second hole-injection layer over the first sacrificial layer and the conductive film;
• forming a second hole-transport layer over the second hole-injection layer;
• forming a second light-emitting layer over the second hole-transport layer;
• forming a second electron-transport layer over the second light-emitting layer;
• forming a second sacrificial layer over the second electron-transport layer;
• processing the second hole-injection layer, the second hole-transport layer, the second light-emitting layer, the second electron-transport layer, and the second sacrificial layer to expose part of the conductive film;
• processing the conductive film with the first sacrificial layer and the second sacrificial layer used as a hard mask to form a first pixel electrode overlapping with the first sacrificial layer and a second pixel electrode overlapping with the second sacrificial layer;
• removing the first sacrificial layer and the second sacrificial layer;
• forming a third electron-transport layer over the first electron-transport layer and the second electron-transport layer;
• forming an electron-injection layer over the third electron-transport layer;
• and
• forming a common electrode over the electron-injection layer.