CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and claims the benefit of priority from the prior Japanese Patent Application No. 2019-154317, filed on Aug. 27, 2019, the entire contents of which are incorporated herein by reference.

FIELD

One embodiment of the present invention is related to a display device and a manufacturing method thereof.

BACKGROUND

Conventionally, an organic EL display device using an organic electroluminescence material (hereinafter, referred to as “organic EL material”) in a light emitting element (hereinafter, referred to as “organic EL element”) of a display region has been known as a display device. The organic EL display device is a so-called self-light emitting type display device which realizes a display by causing an organic EL material to emit light.

A light emitting element included in a display region deteriorates due to moisture. Therefore, in the organic EL display device, the deterioration of the light emitting element is suppressed by providing a sealing film over the light emitting element in order to prevent the entrance of moisture to the light emitting element. For example, Japanese Laid-Open Patent Publication No. 2008-243379 discloses a display device in which a first sealing film and a second sealing film consisting of inorganic materials such as silicon nitride or silicon oxide are provided on a light emitting element. Further, Japanese Laid-Open Patent Publication No. 2005-504652 discloses a structure in which an end portion of a polymer is covered with an inorganic material.

SUMMARY

A display device according to an embodiment of the present invention includes a first region including a light emitting layer, a first nitride insulating layer over the light emitting layer, a first organic insulating layer over the first nitride insulating layer, a second nitride insulating layer over the first organic insulating layer, and a third nitride insulating layer over the second nitride insulating layer. The second nitride insulating layer is in contact with the first organic insulating layer and the third nitride insulating layer. An absolute value of a stress of the second nitride insulating layer is greater than or equal to an absolute value of a stress of the first nitride insulating layer and less than an absolute value of a stress of the third nitride insulating layer.

Further, a display device according to an embodiment of the present invention includes a first region including a light emitting layer, a first nitride insulating layer over the light emitting layer, a first organic insulating layer over the first nitride insulating layer, a second nitride insulating layer over the first organic insulating layer, and a third nitride insulating layer over the second nitride insulating layer. The second nitride insulating layer is in contact with the first organic insulating layer and the third nitride insulating layer. In a wet etching, an etching rate of the second nitride insulating layer is greater than or equal to an etching rate of the first nitride insulating layer and less than or equal to an etching rate of the third nitride insulating layer.

Furthermore, a display device in one embodiment according to the present invention includes a first region including a light emitting layer, a first nitride insulating layer over the light emitting layer, a first organic insulating layer over the first nitride insulating layer, a second nitride insulating layer over the first organic insulating layer, and a third nitride insulating layer over the second nitride insulating layer. The second nitride insulating layer is in contact with the first organic insulating layer and the third nitride insulating layer. An N—H bond ratio of the second nitride insulating layer is greater than an N—H bond ratio of the first nitride insulating layer and less than or equal to an N—H bond ratio of the third nitride insulating layer.

