Semiconductor device and manufacturing method thereof

A manufacturing method of a semiconductor device, comprising:

• forming a first silicon nitride layer on or above a substrate;
• forming a passivation layer above the substrate;
• forming a first silicon nitride material layer above the passivation layer;
• etching the first silicon nitride material layer to obtain a third silicon nitride layer;
• forming a second silicon nitride layer above the first silicon nitride layer, wherein the first silicon nitride layer and the second silicon nitride layer both comprise a hydrogen element, a hydrogen concentration of the second silicon nitride layer is lower than a hydrogen concentration of the first silicon nitride layer, and a thickness of the second silicon nitride layer is less than a thickness of the first silicon nitride layer, wherein a lower surface of the third silicon nitride layer and a lower surface of the second silicon nitride layer are in direct contact with an upper surface of the passivation layer, wherein the third silicon nitride layer comprises a hydrogen element, the hydrogen concentration of the second silicon nitride layer is lower than a hydrogen concentration of the third silicon nitride layer, and the thickness of the second silicon nitride layer is less than a thickness of the third silicon nitride layer;
• forming an oxide insulation layer on the second silicon nitride layer;
• and
• forming a first metal oxide layer on the oxide insulation layer, wherein the second silicon nitride layer is located between the first metal oxide layer and the substrate.