Copper film forming method and manufacturing method of multi-layer wiring substrate

Abstract

A copper film forming method including the steps of spraying a copper formate solution including a copper foramate and a solvent which is evaporated at a certain temperature on a surface of the substrate, and spraying a reducing agent solution including a reducing agent for reducing a copper oxide or undecomposed copper formate on the surface of the substrate to the surface of the substrate. The spraying steps are performed while heating the substrate to the certain temperature and the substrate is placed in an inert gas which is inert at the certain temperature.

1 . A copper film forming method, comprising the steps of:
 spraying a copper formate solution comprising a copper foramate and a solvent which is evaporated at a certain temperature on a surface of the substrate;   spraying a reducing agent solution comprising a reducing agent for reducing a copper oxide or undecomposed copper formate on the surface of the substrate to the surface of the substrate,   wherein the spraying steps are performed while heating the substrate to the certain temperature and   the substrate is placed in an inert gas which is inert at the certain temperature.   
   
   
       2 . The copper film forming method according to  claim 1 , wherein the reducing agent solution is sprayed after spraying the copper formate solution. 
   
   
       3 . The copper film forming method according to  claim 1 , wherein the reducing agent contains an ammonium formate or a formic acid. 
   
   
       4 . The copper film forming method according to  claim 1 , wherein the reducing agent contains a solvent which is evaporated at the certain temperature; 
   
   
       5 . The copper film forming method according to  claim 1 , wherein the step of spraying the copper formate solution and the step of spraying the reducing agent solution is performed alternately. 
   
   
       6 . The copper film forming method according to  claim 1 , wherein the copper formate is thermally decomposed without using a catalyst. 
   
   
       7 . The copper film forming method according to  claim 1 , wherein the inert gas is a nitrogen gas. 
   
   
       8 . The copper film forming method according to  claim 1 , wherein the certain temperature is ranging from 130° C. to 200° C. 
   
   
       9 . The copper film forming method according to  claim 1 , wherein the step of spraying the copper formate solution is performed intermittently. 
   
   
       10 . A manufacturing method of a multi-layer wiring substrate which comprises:
 a semiconductor layer;   a plurality of insulation layer;   a plurality of wiring layer which is made of copper and provided on the respective insulation layers;   vias electrically connecting the respective wiring layers, the manufacturing method comprising:   step of forming a (n)th insulating layer on a (n)th wiring layer;   step of forming a via on the (n)th insulation layer;   step of performing a desmear treatment on the via;   a first reducing agent spraying step of spraying a reducing agent solvent on the via;   a copper formate spraying step of spraying a copper formate solution which comprises a copper formate and solvent evaporated at a certain temperature, on the (n)th insulating layer and the via; and   a second reducing agent spraying step of spraying the reducing agent solution on the (n)th insulation layer and the via,   wherein the “n” is a natural number,   the spraying steps are performed while heating the insulation layer to the certain temperature, and   the insulation layer is placed in an inert gas which is inert at the certain temperature.   
   
   
       11 . The manufacturing method of the multi-layer wiring substrate as set forth in  claim 10 , wherein the second reducing agent spraying step is performed after the copper formate spraying step. 
   
   
       12 . The manufacturing method of the multi-layer wiring substrate as set forth in  claim 10 , wherein the reducing agent contains an ammonium formate or a formic acid. 
   
   
       13 . The manufacturing method of the multi-layer wiring substrate as set forth in  claim 10 , wherein the reducing agent solution comprises a solvent which is evaporated at the certain temperature. 
   
   
       14 . The manufacturing method of the multi-layer wiring substrate as set forth in  claim 10 , the copper formate spraying step and the second reducing agent spraying steps are performed alternately. 
   
   
       15 . The manufacturing method of the multi-layer wiring substrate as set forth in  claim 10 , wherein the copper formate spraying step is performed intermittently.