System, software application, and method for dose uniformity improvement
Embodiments of the present disclosure relate to methods, systems and apparatus for improving dose uniformity of the photolithography system. The method includes projecting a write beam from a projection unit toward a mask to form a plurality of incident lights, adjusting the projection unit to create a distribution of incidence angles corresponding to the incident lights, focusing the plurality of incident lights toward a photoresist layer disposed over a substrate with a lens, removing portions of the photoresist layer to form the device pattern, and forming structures on the substrate corresponding to the device pattern. The mask has a mask pattern corresponding to a device pattern. By focusing the plurality of incident lights towards the photoresist, a swing curve of the incident lights interfere to reduce a total swing curve of the incident lights to develop a photoresist layer with a photoresist pattern corresponding to the device pattern.
1 . A lithography system, comprising:
a projection unit, wherein a size of the projection unit is adjustable to change a distribution of incidence angles corresponding to one or more incident lights;
a mask positioned spaced apart from the projection unit in a projection direction and having a mask pattern corresponding to a device pattern; and
a lens spaced apart from the mask in the projection direction; and
wherein the mask forms the one or more incident lights having a corresponding swing curve from a write beam projected from the projection unit, and wherein the one or more incident lights are focused by the lens to reduce a total swing curve of the incident lights to develop a photoresist layer on a substrate with a photoresist pattern corresponding to the device pattern.
2 . The lithography system of claim 1 , wherein the lens focuses a first incident light, a second incident light, and a third incident light.
3 . The lithography system of claim 1 , wherein the mask is a phase shifting mask and wherein the lens focuses a first incident light and a second incident light.
4 . The lithography system of claim 1 , wherein the projection unit is a dipole projection unit including a first projection unit and a second projection unit, the mask is a phase shifting mask, and wherein the lens focuses a first incident light of the first projection unit, a second incident light of the second projection unit, a third incident light of the first projection unit, and a fourth incident light of the second projection unit to reduce a total swing curve of the incident lights.
5 . The lithography system of claim 1 , wherein the mask is a digital mask having a plurality of mirrors programmed to turn on and off to control a transmission light through the digital mask and wherein the lens focuses a first incident light, a second incident light, and a third incident light to reduce a total swing curve of the incident lights.
6 . The lithography system of claim 1 , wherein the one or more incident lights each have a swing curve corresponding to a thickness of the photoresist layer, an incidence angle of exposure of the incident lights to the photoresist layer, and a wavelength of the incident lights.
7 . A lithography system, comprising:
a circular projection unit, wherein a size of the circular projection unit is adjustable to change a distribution of incidence angles corresponding to one or more incident lights;
a phase shifting mask positioned spaced apart from the circular projection unit in a projection direction and having a mask pattern corresponding to a device pattern; and
a circular illumination phase shifting lens spaced apart from the phase shifting mask in the projection direction; and
wherein the phase shifting mask forms the one or more incident lights having a corresponding swing curve from a write beam projected from the circular projection unit, and wherein the one or more incident lights are focused by the circular illumination phase shifting lens to reduce a total swing curve of the incident lights to develop a photoresist layer on a substrate with a photoresist pattern corresponding to the device pattern.
8 . The lithography system of claim 7 , further comprising a first lens disposed between the circular projection unit and the phase shifting mask.
9 . The lithography system of claim 7 , wherein the substrate is supported by a stage configured to position the substrate in a predetermined path beneath the phase shifting mask.
10 . The lithography system of claim 9 , further comprising a controller in communication with the circular projection unit and configured to control a movement of the substrate via the stage.
11 . The lithography system of claim 10 , further comprising an encoder, wherein the encoder and the circular projection unit are configured to provide information to the controller regarding substrate processing and alignment.
12 . The lithography system of claim 7 , wherein the lens focuses a first incident light, a second incident light, and a third incident light.
13 . The lithography system of claim 7 , wherein the one or more incident lights each have a swing curve corresponding to a thickness of the photoresist layer, an incidence angle of exposure of the incident lights to the photoresist layer, and a wavelength of the incident lights.
14 . A lithography system, comprising:
a dipole projection unit, wherein the size of the dipole projection unit is adjustable to change a distribution of incidence angles corresponding to one or more incident lights;
a dipole illumination phase shifting mask positioned spaced apart from the dipole projection unit in a projection direction and having a mask pattern corresponding to a device pattern; and
a dipole phase shifting lens spaced apart from the dipole illumination phase shifting mask in the projection direction; and
wherein the dipole illumination phase shifting mask forms the one or more incident lights having a corresponding swing curve from a write beam projected from the dipole projection unit, and wherein the one or more incident lights are focused by the dipole phase shifting lens to reduce a total swing curve of the incident lights to develop a photoresist layer on a substrate with a photoresist pattern corresponding to the device pattern.
15 . The lithography system of claim 14 , further comprising a first lens disposed between the dipole projection unit and the dipole illumination phase shifting mask.
16 . The lithography system of claim 14 , wherein the substrate is supported by a stage configured to position the substrate in a predetermined path beneath the dipole illumination phase shifting mask.
17 . The lithography system of claim 16 , further comprising a controller in communication with the dipole projection unit and configured to control a movement of the substrate via the stage.
18 . The lithography system of claim 17 , further comprising an encoder, wherein the encoder and the dipole projection unit are configured to provide information to the controller regarding substrate processing and alignment.
19 . The lithography system of claim 14 , wherein the lens focuses a first incident light, a second incident light, and a third incident light.
20 . The lithography system of claim 14 , wherein the one or more incident lights each have a swing curve corresponding to a thickness of the photoresist layer, an incidence angle of exposure of the incident lights to the photoresist layer, and a wavelength of the incident lights.