Etching method

Abstract

Etching is carried out with an etchant that reacts with a metal to be etched to form an insoluble compound. After the etching using the above etchant, etching is carried out using an etchant that does not form an insoluble compound through a reaction with the metal to be etched, whereby the form of an etched portion comes close to a rectangular form, and the side surface of a conductor pattern becomes smooth. Further, after the etching of one surface of a material to be etched is carried out using an etchant that reacts with a metal to be etched to form an insoluble compound nearly from below, the upper and lower sides of the material to be etched is reversed, and the etching of the opposite surface is carried out nearly from below, whereby fine conductor patterns can be formed on both of the surfaces.

1 . An etching method for etching a material to be etched prepared by forming a resist pattern on a metal layer containing a metal to be etched, the method comprising consecutively carrying out the steps of (1) ejecting an etchant that reacts with the metal to be etched to form a water-insoluble reaction product, by means of a spray nozzle, to perform etching until the etching depth reaches 60% or more of the metal layer thickness, and (2) ejecting an etchant that does not form a water-insoluble reaction product through a reaction with the metal to be etched, by means of a spray nozzle, to perform etching. 
     
     
         2 . The etching method of  claim 1 , wherein an etching speed is 0.3 μm/minute or more but 3 μm/minute or less when the metal to be etched is immersion-etched with the etchant used in the step (2). 
     
     
         3 . The etching method of  claim 1 , wherein the metal to be etched is copper or copper alloy and the etchant used in the step (1) is an etchant containing iron (III) chloride and oxalic acid. 
     
     
         4 . The etching method of  claim 1 , wherein the metal to be etched is copper or copper alloy and the etchant used in the step (2) is an etchant containing iron (III) chloride or copper (II) chloride. 
     
     
         5 . The etching method of  claim 1 , wherein the step (3) of removing said water-insoluble reaction product by using a liquid that dissolves the above water-insoluble reaction product is carried out between the step (1) and the step (2). 
     
     
         6 . The etching method of  claim 5 , wherein the metal to be etched is copper or copper alloy and the etchant used in the step (2) is an etchant containing copper (II) chloride. 
     
     
         7 . An etching method for etching a material to be etched which material is obtained by stacking metal layers each containing a metal to be etched on both surfaces of an insulating material and forming resist patterns on the metal layers, the method comprising consecutively carrying out the three steps of (4) holding the material to be etched horizontally or at an angle of 20° or less from the horizontal and ejecting an etchant containing a compound that reacts with the metal to be etched to form a water-insoluble reaction product, by means of a spray nozzle from below the material to be etched, to etch one surface (surface A) of the material to be etched, (5) reversing the upper and lower sides of the material to be etched, and (6) holding the material to be etched horizontally or at an angle of 20° or less from the horizontal and ejecting the etchant containing a compound that reacts with the metal to be etched to form a water-insoluble reaction product, by means of a spray nozzle from below the material to be etched, to etch that surface (surface B) which is opposite to the surface (A). 
     
     
         8 . The etching method of  claim 7 , wherein the metal to be etched is copper or copper alloy and the etchant containing a compound that reacts with the metal to be etched to form a water-insoluble reaction product is an etchant containing iron (III) chloride and oxalic acid. 
     
     
         9 . The etching method of  claim 7 , wherein the step (7) of removing said water-insoluble reaction product with a liquid that dissolves said water-insoluble reaction product is carried out between the step (4) and the step (6). 
     
     
         10 . The etching method of  claim 2 , wherein the metal to be etched is copper or copper alloy and the etchant used in the step (2) is an etchant containing iron (III) chloride or copper (II) chloride.