Method for forming integrated circuit devices using a phase shifting mask

A device fabrication method comprising the steps of:

• providing a substrate wherein the substrate is transparent to ultraviolet radiation with a wavelength greater than 190 nanometers, the substrate having a front surface and a back surface;
• forming a phase shifting layer of material overlying the front surface of the substrate, the phase shifting layer being transparent to ultraviolet radiation with a wavelength greater than 190 nanometers;
• forming an optical mask overlying the the phase shifting layer, the optical mask being opaque to ultraviolet radiation with a wavelength greater than 190 nanometers;
• depositing an image reversible photoresist layer overlying the optical mask;
• forming a first exposed region and an unexposed region in the image reversible photoresist layer, the first exposed region having a sidewall wherein the sidewall overlies a portion of the optical mask;
• treating the first exposed region to form a hardened first exposed region;
• exposing the back surface of the substrate to an optical illumination source, wherein radiation from the optical illumination source passes through a portion of the substrate to form a second exposed region that lies within a remaining portion of the unexposed region;
• removing the second exposed region to uncover a portion of the phase shifting layer and to form an etch mask, the etch mask comprising the hardened first exposed region and the remaining portion of the unexposed region;
• etching the uncovered portion of the phase shifting layer to form a trench region;
• and
• removing the etch mask to form a phase shifting mask.

A method of fabricating an integrated circuit comprising the steps of:

• providing a substrate wherein the substrate is transparent to ultraviolet radiation with a wavelength greater than 190 nanometers, the substrate having a front surface and a back surface;
• forming a phase shifting layer of material overlying the front surface of the substrate, the phase shifting layer being transparent to ultraviolet radiation with a wavelength greater than 190 nanometers;
• forming an optical mask overlying the phase shifting layer, the optical mask being opaque to ultraviolet radiation with a wavelength greater than 190 nanometers;
• depositing an image reversible photoresist layer overlying the optical mask;
• forming a first exposed region and an unexposed region in the image reversible photoresist layer, the first exposed region having a sidewall wherein the sidewall overlies a portion of the optical mask;
• treating the first exposed region to form a hardened first exposed region;
• exposing the back surface of the substrate to an optical illumination source, wherein radiation from the optical illumination source passes through a portion of the substrate to form a second exposed region that lies within a remaining portion of the unexposed region;
• removing the second exposed region to uncover a portion of the phase shifting layer and to form an etch mask, the etch mask comprising the hardened first exposed region and the remaining portion of the unexposed region;
• etching the uncovered portion of the phase shifting layer to form a trench region;
• and
• removing the etch mask to form a phase shifting mask;
• providing a semiconductor substrate;
• coating the semiconductor substrate with a photoresist layer to form a photoresist coated semiconductor substrate;
• placing the phase shifting mask adjacent to the photoresist coated semiconductor substrate;
• transmitting light through a portion of the phase shifting mask to define an exposure pattern in the photoresist layer;
• and
• developing the photoresist layer to form a photoresist mask overlying the semiconductor substrate.

A method of fabricating an integrated circuit comprising the steps of:

• providing a substrate wherein the substrate is transparent to ultraviolet radiation with a wavelength greater than 190 nanometers, the substrate having a front surface and a back surface;
• forming an optical mask overlying the front surface of the substrate, the optical mask being opaque to ultraviolet radiation with a wavelength greater than 190 nanometers;
• depositing an image reversible photoresist layer overlying the optical mask;
• forming a first exposed region and an unexposed region in the image reversible photoresist layer, the first exposed region having a sidewall wherein the sidewall overlies a portion of the optical mask;
• treating the first exposed region to form a hardened first exposed
• exposing the back surface of the substrate to an optical illumination source, wherein radiation from the optical illumination source passes through a portion of the substrate to form a second exposed region that lies within a remaining portion of the unexposed region;
• removing the second exposed region to uncover a portion of the substrate and to form an etch mask, the etch mask comprising the hardened first exposed region and the remaining portion of the unexposed region;
• etching the uncovered portion of the substrate to form a trench region;
• and
• removing the etch mask to form a phase shifting mask;
• providing a semiconductor substrate;
• coating the semiconductor substrate with a photoresist layer to form a photoresist coated semiconductor substrate;
• placing the phase shifting mask adjacent to the photoresist coated semiconductor substrate;
• transmitting light through a portion of the phase shifting mask to define an exposure pattern in the photoresist layer;
• and
• developing the photoresist layer to form a photoresist mask overlying the semiconductor substrate.

A device fabrication method comprising the steps of:

• providing a substrate wherein the substrate is transparent to ultraviolet radiation with a wavelength greater than 190 nanometers, the substrate having a front surface and a back surface;
• forming an optical mask overlying the front surface of the substrate, the optical mask being opaque to ultraviolet radiation with a wavelength greater than 190 nanometers;
• forming a phase shifting layer of material overlying the optical mask, the phase shifting layer being transparent to ultraviolet radiation with a wavelength greater than 190 nanometers;
• depositing an image reversible photoresist layer overlying the phase shifting layer;
• forming a first exposed region and an unexposed region in the image reversible photoresist layer, the first exposed region having a sidewall wherein the sidewall overlies a portion of the optical mask;
• treating the first exposed region to form a hardened first exposed region;
• exposing the back surface of the substrate to an optical illumination source, wherein radiation from the optical illumination source passes through a portion of the substrate to form a second exposed region that lies within a remaining portion of the unexposed region;
• removing the second exposed region to uncover a portion of the phase shifting layer and to form an etch mask, the etch mask comprising the hardened first exposed region and the remaining portion of the unexposed region;
• etching the uncovered portion of the phase shifting layer to form a trench region;
• and
• removing the etch mask to form a phase shifting mask.

A method of fabricating an integrated circuit comprising the steps of:

• providing a substrate wherein the substrate is transparent to ultraviolet radiation with a wavelength greater than 190 nanometers, the substrate having a front surface and a back surface;
• forming an optical mask overlying the front surface of the substrate, the optical mask being opaque to ultraviolet radiation with a wavelength greater than 190 nanometers;
• forming a phase shifting layer of material overlying the optical mask, the phase shifting layer being transparent to ultraviolet radiation with a wavelength greater than 190 nanometers;
• depositing an image reversible photoresist layer overlying the phase shifting layer;
• forming a first exposed region and an unexposed region in the image reversible photoresist layer, the first exposed region having a sidewall wherein the sidewall overlies a portion of the optical mask;
• treating the first exposed region to form a hardened first exposed region;
• forming a second exposed region wherein the second exposed region lies within a remaining portion of the unexposed region and is formed by exposing the back surface of the substrate to an optical illumination source;
• removing the second exposed region to uncover a portion of the phase shifting layer and to form an etch mask, the etch mask comprising the hardened first exposed region and the remaining portion of the unexposed region;
• etching the uncovered portion of the phase shifting layer to form a trench region;
• and
• removing the etch mask to form a phase shifting mask;
• providing a semiconductor substrate;
• coating the semiconductor substrate with a photoresist layer to form a photoresist coated semiconductor substrate;
• placing the phase shifting mask adjacent to the photoresist coated semiconductor substrate;
• transmitting light through a portion of the phase shifting mask to define an exposure pattern in the photoresist layer;
• and
• developing the photoresist layer to form a photoresist mask overlying the semiconductor substrate.