Electrochemical deposition method, electrochemical deposition apparatus, and microstructure

Abstract

An electrochemical deposition method in which the structure of a substance to be deposited on the surface of a working electrode is determined, an electrochemical deposition apparatus, and a microstructure are provided. A positive electrode 1 and a negative electrode 2 functioning as a working electrode are arranged oppositely in a liquid tank 5 containing an electrolytic (acid) solution (hereinafter referred to as “solution”) 4 in which plural substance are dissolved in an ionic state, and then a predetermined voltage is applied between the positive electrode 1 and the negative electrode 2. A reference electrode 3 is also arranged in the liquid tank 5 and the potential between the negative electrode 2 and the reference electrode 3 is measured. Since the solution 4 can be considered as a conductor, the potential V 1 of the negative electrode 2 relative to the solution 4 can be determined. Furthermore, a reaction inhibitor is admixed in the liquid tank 5, spontaneous electrochemical oscillation (current oscillation in this case) is generated in the electrochemical deposition reaction of the substances in the presence of the reaction inhibitor. The waveform of the electrochemical oscillation is controlled by regulating the potential V 1 of the negative electrode, the concentrations of the substances in the solution, and the kind and concentration of the reaction inhibitor, thereby the structure of a substance to be deposited on the surface of the working electrode is determined.

1 - 17 . (canceled)  
   
   
       18 . An electrochemical deposition method for depositing an electrochemically depositable substance on a surface of a working electrode by applying a voltage or feeding a current between a plurality of electrodes immersed in a solution in which the substance is dissolved in an ionic state, the method comprising: 
 generating electrochemical oscillation by controlling a potential of or the current through the working electrode relative to the solution; and    depositing the substance with a predetermined structure according to a waveform of the electrochemical oscillation.    
   
   
       19 . The method according to  claim 18 , further comprising: 
 mixing a reaction inhibitor into the solution; and    generating a state in which the reaction inhibitor attaches to the surface of the working electrode and a state in which the reaction inhibitor detaches therefrom spontaneously and alternately.    
   
   
       20 . The method according to  claim 18 , further comprising 
 controlling the waveform of the electrochemical oscillation by regulating a concentration of the substance in the solution.    
   
   
       21 . The method according to  claim 18 , wherein 
 a plurality of substances are dissolved in the solution in an ionic state, and    the method further comprises 
 determining a composition ratio of the structure by controlling the waveform of the electrochemical oscillation.  
   
   
   
       22 . The method according to  claim 18 , wherein 
 the structure of the substance deposited according to the waveform of the electrochemical oscillation is a multilayered structure.    
   
   
       23 . The method according to  claim 18 , wherein 
 a metal is used as the substance.    
   
   
       24 . The method according to  claim 18 , wherein 
 the potential of or the current through the working electrode is controlled such that the electrochemical deposition proceeds under diffusion limited control to generate the electrochemical oscillation.    
   
   
       25 . The method according to  claim 19 , wherein 
 the potential of or the current through the working electrode is controlled by regulating a concentration of the reaction inhibitor such that the electrochemical oscillation generates.    
   
   
       26 . The method according to  claim 19 , wherein 
 a cationic surfactant having a carbon chain consisting of 10 carbon atoms or more is used as the reaction inhibitor, and    the potential of or the current into the working electrode is controlled by regulating a length of the carbon chain such that the electrochemical oscillation generates.    
   
   
       27 . The method according to  claim 22 , wherein 
 one of a thickness and a composition ratio of each layer of the multilayered structure are determined by controlling the waveform of the electrochemical oscillation.    
   
   
       28 . The method according to  claim 24 , further comprising: 
 detecting an upper or lower potential on every oscillation of the electrochemical oscillation; and    controlling the current to the working electrode based on variations in the detected upper or lower potentials.    
   
   
       29 . The method according to  claim 28 , wherein 
 the current to the working electrode is controlled such that an effective current density relative to the solution is substantially constant.    
   
   
       30 . The method according to  claim 24 , wherein 
 the waveform of the electrochemical oscillation is controlled by regulating a concentration of the substance in the solution.    
   
   
       31 . An electrochemical deposition apparatus for depositing a substance on a surface of a working electrode by feeding a current between a plurality of electrodes immersed in a solution in which the substance is dissolved in an ionic state and generating electrochemical oscillation, the apparatus comprising: 
 a detector for detecting an upper or lower potential every oscillation of the electrochemical oscillation; and    a current control unit for controlling the current to the working electrode relative to the solution based on the upper or lower potential detected by the detector.    
   
   
       32 . The apparatus according to  claim 31 , wherein 
 the current control unit controls the current to the working electrode, the current corresponding to a current density at which the spontaneous oscillation generates.    
   
   
       33 . A microstructure formed by using the substance deposited by using the electrochemical deposition method according to  claim 18 , wherein the microstructure includes a three-dimensional base structure and is provided with a deposit of another substance thereon.  
   
   
       34 . A microstructure including an internal porous structure shaped by forming the substance deposited by using the electrochemical deposition method according to  claim 18 , polymerizing another substance on a surface of the deposited substance, and removing the deposited substance.