Mask blank, transfer mask, and method for manufacturing semiconductor device

Abstract

This mask blank has a structure wherein a phase shift film and a light shielding film are sequentially formed as layers in this order on a transparent substrate. The optical density of the layered structure composed of the phase shift film and the light shielding film with respect to exposure light, which is an ArF excimer laser, is 3.5 or more; and the light shielding film has a structure wherein a lower layer and an upper layer are formed as layers sequentially from the transparent substrate side. The lower layer is formed from a material wherein the total content of chromium, oxygen, nitrogen and carbon is 90 atomic % or more; and the upper layer is formed from a material wherein the total content of metals and silicon is 80 atomic % or more. The extinction coefficient kU of the upper layer for the exposure light is higher than the extinction coefficient kL of the lower layer for the exposure light.

1 . A mask blank comprising:
 a substrate; and   first and second films formed on the substrate;   wherein the first film is closer to the substrate than the second film is, and   wherein a total content of chromium, oxygen, nitrogen, and carbon in the first film is at least 90 atomic %, and   wherein a content of chromium in the first film is at least 50 atomic %, and   wherein the second film contains metal and silicon, and a total content of metal and silicon is at least 80 atomic %, and   wherein an extinction coefficient k U  of the second film with respect to light having a wavelength of 193 nm is greater than an extinction coefficient k L  of the first film with respect to light having a wavelength of 193 nm.   
     
     
         2 . The mask blank according to  claim 1 , wherein the extinction coefficient k L  of the first film is at most 2.0, and
 wherein the extinction coefficient k U  of the second film is greater than 2.0.   
     
     
         3 . The mask blank according to  claim 1 , wherein a refractive index nu of the second film with respect to light having a wavelength of 193 nm is less than a refractive index n L  of the first film with respect to light having a wavelength of 193 nm, and
 wherein a ratio n U /n L  of the refractive index n U  of the second film to the refractive index n L  of the first film is at least 0.8.   
     
     
         4 . The mask blank according to  claim 3 , wherein the refractive index n L  of the first film is at most 2.0, and
 wherein the refractive index n U  of the second film is less than 2.0.   
     
     
         5 . The mask blank according to  claim 1 , wherein a total content of chromium, oxygen, and carbon in the first film is at least 90 atomic %. 
     
     
         6 . The mask blank according to  claim 1 , wherein a content [atomic %] of metal in the second film is at least five percent of the total content [atomic %] of metal and silicon in the second film. 
     
     
         7 . The mask blank according to  claim 1 , wherein the second film contains tantalum as the metal, and
 wherein a total content of tantalum and silicon in the second film is at least 80 atomic %.   
     
     
         8 . A transfer mask comprising:
 a substrate; and   first and second films formed on the substrate, each of the first and second films having a transfer pattern;   wherein the first film is closer to the substrate than the second film is, and   wherein a total content of chromium, oxygen, nitrogen, and carbon in the first film is at least 90 atomic %, and   wherein a content of chromium in the first film is at least 50 atomic %, and   wherein the second film contains metal and silicon, and a total content of metal and silicon is at least 80 atomic %, and   wherein an extinction coefficient k U  of the second film with respect to light having a wavelength of 193 nm is greater than an extinction coefficient k L  of the first film with respect to light having a wavelength of 193 nm.   
     
     
         9 . The transfer mask according to  claim 8 , wherein the extinction coefficient k L  of the first film is at most 2.0; and
 wherein the extinction coefficient k U  of the second film is greater than 2.0.   
     
     
         10 . The transfer mask according to  claim 8 , wherein a refractive index n U  of the second film with respect to light having a wavelength of 193 nm is less than a refractive index n L  of the first film with respect to light having a wavelength of 193 nm, and
 wherein a ratio n U /n L  of the refractive index n U  of the second film to the refractive index n L  of the first film is at least 0.8.   
     
     
         11 . The transfer mask according to  claim 8 , wherein the refractive index n L  of the first film is at most 2.0, and
 wherein the refractive index n U  of the second film is less than 2.0.   
     
     
         12 . The transfer mask according to  claim 8 , wherein a total content of chromium, oxygen, and carbon in the first film is at least 90 atomic %. 
     
     
         13 . The transfer mask according to  claim 8 , wherein a content [atomic %] of metal in the second film is at least five percent of the total content [atomic %] of metal and silicon in the second film. 
     
     
         14 . The transfer mask according to  claim 8 , wherein the second film contains tantalum as the metal, and
 wherein a total content of tantalum and silicon in the second film is at least 80 atomic %.   
     
     
         15 . A method for manufacturing a semiconductor device, comprising transferring a transfer pattern by exposure to a resist film on a semiconductor substrate using a transfer mask comprising:
 a substrate; and   first and second films formed on the substrate, each of the first and second films having a transfer pattern;   wherein the first film is closer to the substrate than the second film is, and   wherein a total content of chromium, oxygen, nitrogen, and carbon in the first film is at least 90 atomic %, and   wherein a content of chromium in the first film is at least 50 atomic %, and   wherein the second film contains metal and silicon, and a total content of metal and silicon is at least 80 atomic %, and   wherein an extinction coefficient k U  of the second film with respect to light having a wavelength of 193 nm is greater than an extinction coefficient k L  of the first film with respect to light having a wavelength of 193 nm.