Method for fabricating display device including forming pixel electrode, el layer, and sacrificial layer
A method for fabricating a display device that easily achieves higher resolution is provided. A display device having both high display quality and high resolution is provided. A first EL film is formed over a first pixel electrode and a second pixel electrode; a first sacrificial film is formed to cover the first EL film; the first sacrificial film and the first EL film are etched to expose the second pixel electrode and to form a first EL layer over the first pixel electrode and a first sacrificial layer over the first EL layer; and the first sacrificial layer is removed. The first EL film and the second EL film are etched by dry etching, and the first sacrificial layer is removed by wet etching.
1 . A method for fabricating a display device, comprising:
a first step of forming a first EL film over a first pixel electrode and a second pixel electrode;
a second step of forming a first sacrificial film covering the first EL film;
a third step of etching the first sacrificial film and the first EL film to expose the second pixel electrode and to form a first EL layer over the first pixel electrode and a first sacrificial layer over the first EL layer;
a fourth step of forming a second EL film over the first sacrificial layer and the second pixel electrode;
a fifth step of forming a second sacrificial film covering the second EL film;
a sixth step of etching the second sacrificial film and the second EL film to expose the first sacrificial layer and to form a second EL layer over the second pixel electrode and a second sacrificial layer over the second EL layer;
a seventh step of removing the first sacrificial layer and the second sacrificial layer; and
an eighth step of drying the first EL layer and the second EL layer,
wherein the first EL film and the second EL film are etched by dry etching, and
wherein the first sacrificial layer and the second sacrificial layer are removed by wet etching.
2 . The method for fabricating a display device, according to claim 1 ,
wherein the first sacrificial film comprises a resin material dissolved in water or alcohol,
wherein the first sacrificial film and the first EL film are successively etched by dry etching in an atmosphere comprising oxygen in the third step, and
wherein the first sacrificial layer and the second sacrificial layer are removed by being dissolved in water or alcohol in the seventh step.
3 . The method for fabricating a display device, according to claim 1 ,
wherein the first sacrificial film comprises a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic insulating film,
wherein the first EL film is etched by dry etching using an etching gas not comprising oxygen as a main component in the third step, and
wherein the first sacrificial layer and the second sacrificial layer are removed by wet etching using a tetramethyl ammonium hydroxide solution, diluted hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution of any of the tetramethyl ammonium hydroxide solution, the diluted hydrofluoric acid, the oxalic acid, the phosphoric acid, the acetic acid, and the nitric acid in the seventh step.
4 . The method for fabricating a display device, according to claim 1 , further comprising a ninth step of forming a hard mask between the second step and the third step,
wherein the first sacrificial film is etched using the hard mask and then the hard mask and the first EL film are etched by the same process in the third step.
5 . The method for fabricating a display device, according to claim 1 , wherein the first EL layer and the second EL layer are each processed to have a belt-shaped top surface.
6 . The method for fabricating a display device, according to claim 1 , wherein the first EL layer and the second EL layer are each processed to have an island-shaped top surface.
7 . The method for fabricating a display device, according to claim 1 , further comprising a tenth step of forming a common electrode over the first EL layer and the second EL layer and an eleventh step of forming a protective layer over the common electrode after the eighth step.
8 . The method for fabricating a display device, according to claim 7 , further comprising a twelfth step of forming a common layer over the first EL layer and the second EL layer between the eighth step and the tenth step.
9 . The method for fabricating a display device, according to claim 1 , further comprising a thirteenth step of forming optical adjustment layers with different thicknesses over the first pixel electrode and the second pixel electrode before the first step.
10 . A method for fabricating a display device, comprising:
a first step of forming a first EL film over a first pixel electrode and a second pixel electrode;
a second step of forming a first sacrificial film covering the first EL film;
a third step of etching the first sacrificial film and the first EL film to expose the second pixel electrode and to form a first EL layer over the first pixel electrode and a first sacrificial layer over the first EL layer;
a fourth step of forming a second EL film over the first sacrificial layer and the second pixel electrode;
a fifth step of forming a second sacrificial film covering the second EL film;
a sixth step of etching the second sacrificial film and the second EL film to expose the first sacrificial layer and to form a second EL layer over the second pixel electrode and a second sacrificial layer over the second EL layer;
a seventh step of removing the first sacrificial layer and the second sacrificial layer; and
an eighth step of drying the first EL layer and the second EL layer,
wherein each of the first sacrificial layer and the second sacrificial layer comprises a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic insulating film.
11 . A method for fabricating a display device, comprising:
a first step of forming a first EL film over a first pixel electrode and a second pixel electrode;
a second step of forming a first sacrificial film covering the first EL film;
a third step of forming a first resist mask over the first sacrificial film in a region overlapping with the first pixel electrode;
a fourth step of etching the first sacrificial film and the first EL film using the first resist mask to expose the second pixel electrode and to form a first EL layer over the first pixel electrode and a first sacrificial layer over the first EL layer;
a fifth step of forming a second EL film over the first resist mask and the second pixel electrode;
a sixth step of forming a second sacrificial film covering the second EL film;
a seventh step of forming a second resist mask over the second sacrificial film in a region overlapping with the first pixel electrode and a region overlapping with the second pixel electrode;
an eighth step of etching the second sacrificial film and the second EL film using the second resist mask to expose the first sacrificial layer and to form a second EL layer over the second pixel electrode and a second sacrificial layer over the second EL layer;
a ninth step of removing the first sacrificial layer and the second sacrificial layer; and
a tenth step of drying the first EL layer and the second EL layer,
wherein each of the first sacrificial layer and the second sacrificial layer comprises a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic insulating film.