Etching method

Abstract

An etching method includes: providing a substrate including a silicon oxide film on a stage; controlling a surface temperature of the substrate to be −70° C. or lower; and etching the silicon oxide film with plasma generated by supplying a radio-frequency power to a gas containing fluorine and hydrogen, after the controlling the surface temperature of the substrate; and increasing the surface temperature of the substrate to volatilize a by-product generated by the etching.

What is claimed is: 
     
         1 . A method of etching comprising:
 providing, on a stage, a substrate having a silicon-containing film including a silicon oxide film and a carbon containing mask disposed on the silicon-containing film;   cooling the stage to be 0° C. or lower;   etching the silicon-containing film with a plasma generated from a gas containing a hydrogen fluoride (HF) gas and at least one selected from the group consisting of a fluorocarbon gas and a hydrofluorocarbon gas using a first radio-frequency power (HF power); and   increasing a surface temperature of the substrate such that a by-product generated by the etching is volatilized,   wherein the increasing of the surface temperature of the substrate is performed while the etching of the silicon-containing film is being performed with the plasma.   
     
     
         2 . The method of  claim 1 , wherein the fluorocarbon gas is at least one selected from the group consisting of CF 4 , C 2 F 6 , C 4 F 6  and C 4 F 8 . 
     
     
         3 . The method of  claim 1 , wherein the carbon containing mask includes amorphous carbon. 
     
     
         4 . The method of  claim 1 , wherein an ending temperature of the etching the silicon-containing film is higher by 30° C. or more than a starting temperature of the etching the silicon-containing film. 
     
     
         5 . The method of  claim 1 , wherein the etching further includes drawing ions in the plasma into the substrate by supplying a second radio-frequency power (LF power) having a frequency lower than a frequency of the first radio-frequency power, and
 each of the LF power and the HF power is a pulse wave.   
     
     
         6 . The method of  claim 1 , wherein the silicon containing film further includes a silicon nitride film (SiN), and
 the silicon oxide film (SiOx) and the silicon nitride film (SiN) are alternately stacked on the substrate.   
     
     
         7 . A method of etching comprising:
 providing, on a stage, a substrate having a silicon-containing film including a silicon oxide film and a mask disposed on the silicon-containing film;   after the providing, cooling the stage to be 0° C. or lower;   after the cooling of the stage, etching the silicon-containing film with a plasma generated from a hydrogen containing gas and a fluoride containing gas and at least one selected from the group consisting of a fluorocarbon gas and a hydrofluorocarbon gas using a first radio-frequency power (HF power); and   increasing a surface temperature of the substrate such that a by-product generated by the etching is volatilized,   wherein the increasing of the surface temperature of the substrate is performed while the etching of the silicon-containing film is being performed with the plasma.   
     
     
         8 . The method of  claim 7 , wherein an ending temperature of the etching the silicon-containing film is higher by 30° C. or more than a starting temperature of the etching the silicon-containing film. 
     
     
         9 . The method of  claim 7 , wherein the mask includes metal or carbon. 
     
     
         10 . The method of  claim 8 , wherein the metal is tungsten (W), titanium (Ti), molybdenum (Mo), ruthenium (Ru), Hafnium (Hf), or aluminum (Al). 
     
     
         11 . The method of  claim 7 , wherein a pressure in a space between a back surface of the substrate and a surface of the stage is set to 10 Torr to 200 Torr. 
     
     
         12 . The method of  claim 7 , wherein the increasing of the temperature of the substrate is performed by at least one of:
 adjusting a pressure in a space between a back surface of the substrate and a surface of the stage,   adjusting a second radio-frequency power (LF power) having a frequency lower than a frequency of the first radio-frequency power supplied to draw ions in the plasma into the substrate,   adjusting a duty ratio of the LF power,   adjusting a temperature of a heat exchange medium flown to the stage, and   irradiating a heat source such as radiation, microwave, UV light, infrared light, visible light or laser.   
     
     
         13 . The method of  claim 7 , wherein the surface temperature of the substrate increases as an aspect ratio of a recess formed by the etching increases. 
     
     
         14 . The method of  claim 7 , wherein the etching further includes supplying a second radio-frequency power (LF power) having a frequency lower than a frequency of the first radio-frequency power of 10 kW or more. 
     
     
         15 . The method of  claim 14 , wherein the second radio-frequency power (LF power) is a pulse wave having a predetermined duty ratio. 
     
     
         16 . The method of  claim 15 , wherein the duty ratio is changed while the etching is being performed. 
     
     
         17 . The method of  claim 7 , wherein the silicon-containing film is used for a high aspect etching with a high aspect ratio of 30 or more for a 3D-NAND or DRAM. 
     
     
         18 . The method of  claim 8 , wherein
 the mask includes metal or carbon,   a pressure in a space between a back surface of the substrate and a surface of the stage is set to 10 Torr to 200 Torr,   the etching further includes supplying a second radio-frequency power (LF power) having a frequency lower than frequency of the first radio-frequency power of 10 kW or more, and   the second radio-frequency power (LF power) is a pulse wave having a predetermined duty ratio.   
     
     
         19 . An etching apparatus comprising:
 a processing chamber including a stage on which a substrate is placed,   a radio-frequency power source configured to supply a radio-frequency power into the processing chamber to generate plasma in the processing chamber;   a heat source configured to adjust a surface temperature of the substrate; and   a controller configured to control an overall operation of the etching apparatus,   wherein the controller is programed to:
 provide the substrate on the stage, the substrate having a silicon-containing film including a silicon oxide film and a mask disposed on the silicon-containing film, 
 after the substrate is provided on the stage, cool the stage to be 0° C. or lower, 
 after the stage is cooled, etch the silicon-containing film with a plasma generated from a hydrogen containing gas and a fluoride containing gas and at least one selected from the group consisting of a fluorocarbon gas and a hydrofluorocarbon gas using the radio-frequency power source; and 
 increase a surface temperature of the substrate using the heat source such that a by-product generated by the etching is volatilized, 
 wherein the surface temperature of the substrate is increased while the silicon-containing film is being etched with the plasma.