Manufacturing method of display device, display device, display module, and electronic device

A method for manufacturing a display device, comprising:

• forming a first pixel electrode, a second pixel electrode, and a first conductive layer;
• forming a first film over the first pixel electrode and the second pixel electrode;
• forming a first mask film over the first film and the first conductive layer;
• processing the first film and the first mask film to form a first layer and a first mask layer over the first pixel electrode, form a second mask layer over the first conductive layer, and expose the second pixel electrode;
• forming a second film over the first mask layer and the second pixel electrode;
• forming a second mask film over the second film;
• processing the second film and the second mask film to form a second layer and a third mask layer over the second pixel electrode and expose the first mask layer and the second mask layer;
• forming a first insulating film over the first mask layer to the third mask layer;
• forming a second insulating film over the first insulating film with use of a photosensitive resin composite;
• performing light exposure and development on the second insulating film to expose a portion of the first insulating film that overlaps with the second mask layer;
• performing first etching treatment using the second insulating film as a mask to remove the portion of the first insulating film that overlaps with the second mask layer and reduce a thickness of part of the second mask layer;
• performing light exposure and development on the second insulating film to expose a portion of the first insulating film that overlaps with the first mask layer and a portion of the first insulating film that overlaps with the third mask layer, and form a second insulating layer overlapping with a region interposed between the first pixel electrode and the second pixel electrode;
• performing second etching treatment using the second insulating layer as a mask to remove the portion of the first insulating film that overlaps with the first mask layer and the portion of the first insulating film that overlaps with the third mask layer, form a first insulating layer overlapping with the second insulating layer, and reduce a thickness of part of the first mask layer and part of the third mask layer;
• performing heat treatment and then performing third etching treatment using the second insulating layer as a mask to remove part of the first mask layer and part of the third mask layer and expose a top surface of the first layer and a top surface of the second layer;
• forming a common electrode to cover the first layer, the second layer, the first conductive layer, and the second insulating layer;
• and
• removing part of the second mask layer by the second etching treatment or the third etching treatment to expose a top surface of the first conductive layer.

A display device comprising:

• a first light-emitting device;
• a second light-emitting device;
• a first lens;
• a second lens;
• a first insulating layer;
• and
• a second insulating layer,
• wherein the first light-emitting device comprises a first pixel electrode, a first light-emitting layer over the first pixel electrode, and a common electrode over the first light-emitting layer,
• wherein the second light-emitting device comprises a second pixel electrode, a second light-emitting layer over the second pixel electrode, and the common electrode over the second light-emitting layer,
• wherein the first lens overlaps with the first light-emitting device,
• wherein the second lens overlaps with the second light-emitting device,
• wherein the first insulating layer covers a side surface and part of a top surface of the first light-emitting layer and a side surface and part of a top surface of the second light-emitting layer,
• wherein the second insulating layer overlaps with the side surface and the part of the top surface of the first light-emitting layer and the side surface and the part of the top surface of the second light-emitting layer with the first insulating layer therebetween,
• wherein the common electrode covers the second insulating layer, and
• wherein in a cross-sectional view, an end portion of the second insulating layer has a tapered shape with a taper angle less than 90°.