Adaptive Tip-Withdrawal Control for Reliable Microfabrication by Localized Electrodeposition

Improved Copper Microcolumn Fabricated by Localized Electrochemical Deposition

“…Consequently, the LECD process is generally less expensive than the LIGA process. [5][6][7] Furthermore, LECD avoids the difficulty in filling the solution inside high aspect ratio patterns encountered during LIGA processing.…”

“…LECD is generally performed with micrometer-sized insoluble anode and conductive cathode immersed in the solution containing metal ions which, once reduced, bring about the microstructures. [3][4][5][6][7][8][9][10][11] The feasibility of forming the microstructure is related to the following factors: the applied voltage and distance between the two electrodes, 3,[5][6][7][8][9] the fabrication procedure, geometry, 3 rotation and vibration of the electrodes, 10,11 and the composition and additives of the electrolyte. 5 On the other hand, the shape and dimension of the microstructure are controlled by the relative motion of the anode to the cathode.…”

“…5 On the other hand, the shape and dimension of the microstructure are controlled by the relative motion of the anode to the cathode. 3,6,9 When the dc current is employed, the applied potential and the distance between the anode and cathode have been shown to markedly affect the growth of the microstructures. A critical voltage is required for a given anode-cathode distance, below which electrocrystallization would not occur.…”

Mask-Less Electrochemical Additive Manufacturing: A Feasibility Study

“…The choice of electrolyte for the electrodeposition process has so far been derived mostly from the electrolyte used for the electroplating of the same metal. Repeatability of localized electrochemical dep osition has been a challenge due to the lack of a proper feedback gap control to maintain a stable interelectrode gap [25]. Accumulation of bubbles, which hinder the deposition by blocking the interelectrode gap region, is a reason for the nonimplementation of electrodeposition over longer periods.…”

Microelectrochemical Deposition

“…The output of the integrator is used to tune a voltage-controlled oscillator that generates pulses at a rate proportional to the tuning voltage amplitude and is also used to trigger positioner movement at a speed corresponding to the generated pulse rate. The pulse generation rate would thus be modulated by the total change in the deposition current resulting from either a decrease in the tipdeposit spacing due to deposition growth, or from an increase in the tip-deposit spacing due to tip withdrawal away from the deposit end (29). Figure 7 shows a scanning electron microscope (SEM) image of an example of a successfully deposited copper column, which has a diameter of about 25 mm and a length of about 6.5 mm, thus giving an aspect ratio of 1:282.…”