Method and electrode for defining and replicating structures in conducting materials

Abstract

The present invention concerns an electrochemical pattern replication method, ECPR, and a construction of a conductive electrode for production of applications involving micro and nano structures. An etching or plating pattern, which is defined by a conductive electrode, a master electrode, is replicated on an electrically conductive material, a substrate. The master electrode is put in close contact with the substrate and the etching/plating pattern is directly transferred onto the substrate by using a contact etching/plating process. The contact etching/plating process is performed in local etching/plating cells, that are formed in closed or open cavities between the master electrode and the substrate.

1 . An electrochemical pattern replication method for production of micro- or nano-structures of an electrically conductive material on a substrate ( 9 ), whereby an etching or plating pattern is replicated, defined by an electrically insulating patterned material, said method comprising 
 using an electrochemical process for transferring said pattern onto the substrate ( 9 ),    said electrochemical process comprising dissolving a material at an anodic surface and depositing the material at a cathodic surface, characterized by    placing a master electrode ( 8 ) in close contact with the substrate ( 9 ) so that the pattern is defined using the master electrode ( 8 ), and    said dissolving and depositing of material being performed in local etching or plating cells ( 12 , 14 ) being formed in closed or open cavities, delimited by an insulating pattern layer ( 3 ) of the master electrode ( 8 ), and the substrate ( 9 ),    the master electrode ( 8 ) being the anodic surface and the substrate being the cathodic surface and the material being dissolved being a predeposited material on the mister electrode in the local plating cells ( 14 ), or    the substrate ( 9 ) being said anodic surface and the master electrode being said cathodic surface and said cavities being local etching cells ( 12 ).    
   
   
       2 . The method according to  claim 1 , characterized by the steps of 
 charging the cavities on the master electrode ( 8 ) with an electrolyte solution ( 6 );    compressing the substrate ( 9 ) and the master electrode ( 8 ) in close contact, thereby creating the local etching cells ( 12 ) charged with the electrolyte solution ( 6 ); and    connecting an external voltage between the substrate ( 9 ), which is the anode, and the master electrode ( 8 ), which is the cathode.    
   
   
       3 . The method according to  claim 1 , characterized by the steps of predepositing a plating material ( 15 ) in the cavities on the master electrode ( 8 ) and charging them with an electrolyte solution ( 6 ); 
 compressing the substrate ( 9 ) and the master electrode ( 8 ) in close contact, thereby creating the local plating cells ( 14 ) charged with the electrolyte solution ( 6 ); and    connecting an external voltage between the substrate ( 9 ), which is the cathode, and the master electrode ( 8 ), which is the anode.    
   
   
       4 . The method according to any of  claims 1  to  3 , characterized by a distance between the master electrode ( 8 ) and the substrate ( 9 ) being determined by the thickness of the insulating pattern layer ( 3 ).  
   
   
       5 . The method according to  claim 2 , characterized by a further step of cleaning of the master electrode ( 8 ), after a number of etching cycles.  
   
   
       6 . The method according to  claim 5 , characterized by the cleaning step being an etching process, where deposit material ( 13 ) on the master electrode is etched away.  
   
   
       7 . The method according to any of the preceding claims, characterized by using pulsed voltage applied between the master electrode ( 8 ) and the substrate ( 9 ).  
   
   
       8 . The method according to  claim 7 , characterized in that the frequency is in the range of 2 to 20 kHz.  
   
   
       9 . The method according to  claim 7 , characterized in theft the frequency is 5 kHz.  
   
   
       10 . The method according to any of  claims 7  to  9 , characterized in that the pulsed voltage is a periodic pulse reverse voltage.  
   
   
       11 . The method according to any of  claims 7  to  10 , characterized in that the pulsed voltage has complex waveforms.  
   
   
       12 . The method according to  claim 2  or  3 , characterized in that the electrolyte solution ( 6 ) has no or less supporting electrolyte and a high concentration of electro active species and/or no chemical oxidation agent.  
   
   
       13 . The method according to  claim 2  or  3 , characterized in that counter ions in the electrolyte solution ( 6 ) is exchanged to ones which provide higher solubility.  
   
   
       14 . The method according to  claim 2  or  3 , characterized in that a concentration of electro active ions of 10 to 1200 mM in the electrolyte solution ( 6 ) is used and/or that a sequestering agent is used.  
   
   
       15 . The method according to  claim 14 , characterized in that sequestering agent is EDTA.  
   
   
       16 . The method according to  claim 2  or  3  characterized in that an additive system is used in the electrolyte solution ( 6 ), comprising wetting agents, accelerators, suppressors and/or levelers.  
   
   
       17 . The method according to  claim 2  or  3 , characterized in that the electrolyte solution ( 6 ) comprises acid copper and the electrolyte ( 6 ) has a pH value between 2 and 5.  
   
   
       18 . The method according to any of  claims 12  to  17 , characterized using said electrolyte solution ( 6 ) being an optimised electrolyte in the local etching cells ( 12 ) or the local plating cells ( 14 ).  
   
   
       19 . An electrode suitable for an etching or plating process, characterized in that a counter electrode ( 1 ) and a pattern defining structure of an electro chemical etching or plating cell are integrated into a master electrode ( 8 ), wherein the counter electrode ( 1 ) is a conducting electrode layer ( 1 ′) or a flexible conducting foil ( 1 ″), and the pattern defining structure is an insulating pattern layer ( 3 ) being applied on said counter electrode ( 1 ).  
   
   
       20 . The electrode according to  claim 19 , characterized in that the counter electrode ( 1 ) is inert.  
   
   
       21 . The electrode according to  claim 19  or  20  characterized in that a flexible elastomer layer ( 20 ) is applied on the insulating pattern layer ( 3 ).  
   
   
       22 . The electrode according to any of  claims 19  to  21  characterized in that the counter electrode ( 1 ) is applied on a mechanical support layer ( 23 ).  
   
   
       23 . The electrode according to  claim 22  characterized in that a conductive elastomer layer ( 21 ) is applied between the counter electrode ( 1 ) and the mechanical support layer ( 23 ).  
   
   
       24 . The electrode according to  claim 21  or  22  characterized in that an intermediate metal layer ( 22 ) is applied between the insulating pattern layer ( 3 ) and the flexible elastomer layer ( 20 ).  
   
   
       25 . The electrode according to any  claim 19  characterized in that the flexible conducting foil ( 1 ″) is made of titanium.  
   
   
       26 . The electrode according to  claim 24  or  25  characterized in that the master electrode ( 8 ) comprises two counter electrodes ( 1 ) with a sacrificial photo-resist layer ( 17 ) applied in between and that contact parts of the master electrode, structures of the insulating pattern layer ( 3 ), are electrochemically anodised to form an isolating layer.  
   
   
       27 . An apparatus for performing the method according to  claim 1 , characterized by comprising a master electrode ( 8 ) and means for creating conformable contact between the master electrode ( 8 ) and a substrate ( 9 ).  
   
   
       28 . The apparatus according to  claim 27 , characterized in that said means are one or more elastomer layers in the master electrode construction.  
   
   
       29 . The apparatus according to claims  27  or  28 , characterized in that said means are combined with a conformable membrane.  
   
   
       30 . The apparatus according to  claim 27 , characterized in that there are conducting means for electrical connection to the master electrode ( 8 ) on an outer side ( 10 ) and electrical connection to the substrate ( 9 ) on a contact side ( 11 ).  
   
   
       31 . The apparatus according to  claim 27 , characterized in that the master electrode ( 8 ) is fixed in the apparatus by an applied vacuum.  
   
   
       32 . The apparatus according to  claim 30 , characterized in that said conducting means for electrical connections is a conducting piece ( 28 ) applied on the outer side ( 10 ) of the master electrode ( 8 ).  
   
   
       33 . The apparatus according to any of  claims 27  to  32 , characterized in that the master electrode is fixed in the apparatus by a pressure against a conducting piece, said pressure exerted by the conformable membrane and/or a piston.  
   
   
       34 . The apparatus according to  claim 33 , characterized in that said pressure when applied with the conformable membrane is combined with a reservoir containing gas or liquid.  
   
   
       35 . The apparatus according to any of  claims 27  to  34 , characterized in that gas bubbles are eliminated from in electrolyte solution ( 6 ) and/or the reservoir by use of an externally applied vacuum, ultrasound or a combination of vacuum and ultrasound.