Apparatus for fabricating a semiconductor device and method of doing the same

Abstract

There is provided a method of fabricating a semiconductor device, including the steps of (a) generating plasma in the following conditions: (a1) an RF bias voltage has a frequency equal to or greater than 1 MHz, (a2) an RF source voltage has a frequency equal to or greater than 1 MHz, (a3) the RF source voltage is modulated by pulses in a cycle equal to or greater than 100 μsec, and (a4) pulse-on time is equal to or greater than 50 μsec, and (b) patterning multi-layered metal wirings by etching through the plasma The method makes it possible to reduce charging damage to a gate insulating film, even if wirings are further spaced away from adjacent ones and/or an antenna ratio of multi-layered metal wirings is further increased.

What is claimed is:  
     
         1 . A method of fabricating a semiconductor device, comprising the steps of: 
 (a) generating plasma in the following conditions: 
 (a1) an RF bias voltage has a frequency equal to or greater than 1 MHz;  
 (a2) an RF source voltage has a frequency equal to or greater than 1 MHz;  
 (a3) said RF source voltage is modulated by pulses in a cycle equal to or greater than 100 μsec; and  
 (a4) pulse-on time is equal to or greater than 50 μsec, and  
   (b) patterning multi-layered metal wirings by etching through said plasma.    
     
     
         2 . The method as set forth in  claim 1 , wherein said pulses have a rectangular waveform.  
     
     
         3 . The method as set forth in  claim 1 , wherein said cycle is equal to or smaller than 500 μsec, and said pulse-on time is equal to or smaller than 450 μsec.  
     
     
         4 . The method as set forth in  claim 1 , wherein said multi-layered metal wirings are composed of aluminum or aluminum alloy.  
     
     
         5 . The method as set forth in  claim 4 , wherein said multi-layered metal wirings make electrical contact with an n-channel MOSFET.  
     
     
         6 . The method as set forth in  claim 5 , wherein said n-channel MOSET includes a gate insulating film having a thickness equal to or smaller than 6 nm.  
     
     
         7 . The method as set forth in  claim 1 , wherein said multi-layered metal wirings have an antenna ratio in the range of 1,000 to 100,000 both inclusive, and wirings in said multi-layered metal wirings are spaced away from adjacent ones by 0.3 μm or greater.  
     
     
         8 . The method as set forth in  claim 7 , wherein said multi-layered metal wirings have an antenna ratio in the range of 1,000 to 40,000 both inclusive.  
     
     
         9 . The method as set forth in  claim 1 , wherein pulse-off time is equal to or smaller than 100 μsec.  
     
     
         10 . The method as set forth in  claim 9 , wherein said pulse-off time is equal to or greater than 20 μsec.  
     
     
         11 . The method as set forth in  claim 10 , wherein said pulse-off time is equal to or greater than 30 μsec.  
     
     
         12 . An apparatus for fabricating a semiconductor device, comprising: 
 (a) a hermetically sealed chamber;    (b) a gas introducer introducing gas into said chamber;    (c) a gas exhauster exhausting gas from said chamber;    (d) an RF source voltage supplier applying an RF source voltage having a frequency equal to or greater than 1 MHz to said chamber to thereby generate inducive coupling plasma from said gas;    (e) an RF bias voltage source applying an RF bias voltage to a substrate put in said chamber, said RF bias voltage having a frequency equal to or greater than 1 MHz; and    (f) a pulse generator which transmits pulses to said RF source voltage supplier to thereby modulate said RF source voltage in a cycle equal to or greater than 100 μsec with pulse-on time being kept equal to or greater than 50 μsec.    
     
     
         13 . The apparatus as set forth in  claim 12 , wherein said pulse generator generates pulses each having a rectangular waveform.  
     
     
         14 . The apparatus as set forth in  claim 12 , wherein said pulse generator transmits to said RF source voltage supplier to thereby modulate said RF source voltage in a cycle equal to or smaller than 500 μsec with said pulse-on time being kept equal to or smaller than 450 μsec.  
     
     
         15 . The apparatus as set forth in  claim 12 , wherein said semiconductor device includes multi-layered metal wirings composed of aluminum or aluminum alloy.  
     
     
         16 . The apparatus as set forth in  claim 15 , wherein said semiconductor device further includes an n-channel MOSFET with which said multi-layered metal wirings make electrical contact.  
     
     
         17 . The apparatus as set forth in  claim 16 , wherein said n-channel MOSET includes a gate insulating film having a thickness equal to or smaller than 6 nm.  
     
     
         18 . The apparatus as set forth in  claim 15 , wherein said multi-layered metal wirings have an antenna ratio in the range of 1,000 to 100,000 both inclusive, and wirings in said multi-layered metal wirings are spaced away from adjacent ones by 0.3 μm or greater.  
     
     
         19 . The apparatus as set forth in  claim 18 , wherein said multi-layered metal wirings have an antenna ratio in the range of 1,000 to 40,000 both inclusive.  
     
     
         20 . The apparatus as set forth in  claim 12 , wherein said pulse generator transmits pulses to said RF source voltage supplier to thereby modulate said RF source voltage with pulse-off time being equal to or smaller than 100 μsec.  
     
     
         21 . The apparatus as set forth in  claim 20 , wherein said pulse-off time is equal to or greater than 20 μsec.  
     
     
         22 . The apparatus as set forth in  claim 21 , wherein said pulse-off time is equal to or greater than 30 μsec.