Electro-deposition of nano-patterns
View Patent ↗The present disclosure generally relates to techniques for electro-depositing nano-patterns. More specifically, systems and methods for fabricating periodic structures in complex nano-patterns are described. An electrical signal may be applied to one or more electrodes that are positioned about a surface of a substrate. The periodicity of the deposited pattern may be influenced by one or more parameters associated with an applied electrical signal, including one or more of frequency, amplitude, period, duty cycle, etc. The weight of each deposited line on the substrate may be influenced by the described parameters, and the shape of the pattern may be influenced by the number, shape, and position of electrodes.
1. A method for electro-depositing a desired pattern on a surface of a substrate comprising:
providing a substrate in contact with an electrolyte solution containing a material for electroplating;
positioning a plurality of shaped electrodes at different locations on the surface of the substrate in a closed loop configuration, wherein a polarity associated with the plurality of electrodes is arranged to alternate along the closed loop configuration; and
applying an electrical current signal to at least one of the plurality of electrodes, wherein applying an electrical current signal to the at least one electrode generates equi-potential lines and forms a conductive path along the closed loop configuration,
wherein the electro-depositing occurs along the equi-potential lines resulting in a pattern extending along the equipotential lines in a plane parallel to a plane defined by the surface of the substrate, and
wherein the pattern includes a curved line.
2. The method of claim 1 , wherein the electrical current signal corresponds to a semi-sine wave.
3. The method of claim 2 , wherein a frequency associated with the semi-sine wave ranges from approximately 0.4 Hz to approximately 1.2 Hz.
4. The method of claim 1 , wherein the pattern is different from a straight line.
5. The method of claim 1 , further comprising subdividing the substrate into chip sizes.
6. The method of claim 5 , wherein subdividing is done before applying the electrical current signal across the surface of the substrate.
7. The method of claim 5 , wherein subdividing is done after applying the electrical current signal across the surface of the substrate.
8. The method of claim 1 , wherein at least two electrodes from the plurality of shaped electrodes have the same polarity.
9. The method of claim 1 , wherein at least one of the plurality of electrodes is a sacrificial anode.
10. The method of claim 1 , wherein applying an electrical current signal comprises forming a closed mop between the plurality of shaped electrodes.
11. The method of claim 1 , wherein positioning a plurality of shaped electrodes comprises positioning a first electrode at a first location and a second electrode at as second location that is different from the first location, and wherein applying an electrical current comprises forming a conductive path between the first electrode and the second electrode.
12. The method of claim 1 , wherein applying an electrical current comprises applying a time-varying signal between the plurality of shaped electrodes.
13. The method of claim 1 , further comprising modulating a frequency of the electrical current signal.
14. The method of claim 1 , further comprising varying one or more of amplitude of the electrical current, exposure time, pulse duration, pulse period, or duty cycle.
15. The method of claim 1 , further comprising, prior to providing a substrate in contact with an electrolyte solution, preparing the substrate to enhance suitability of the surface of the substrate for electro-deposition.
16. The method of claim 1 , further comprising, prior to providing a substrate in contact with the electrolyte solution, coating the substrate with one of a hydrophilic coating, a conductive coating, or an electro-plating seed layer.
17. The method of claim 1 , further comprising depositing a first line having a first weight and a second line having a second weight different from the first weight.
18. The method of claim 1 , wherein the electrical current signal is received by a first electrode of the plurality of electrodes.
19. The method of claim 1 , wherein the electrical current signal is received by each of the plurality of electrodes.
20. The method of claim 1 further comprising replenishing deposited ions when the plurality of electrodes are mostly formed from a non-consumable material.
21. The method of claim 1 , where in the plurality of electrodes are positioned such that a line drawn from one electrode to the next would form a dosed loop.
22. The method of claim 1 , wherein a first, a third, and a fifth electrode have a positive polarity, and a second, a fourth, and a sixth electrode have a negative polarity.
23. The method of claim 1 , wherein the closed loop configuration is one of a circle, an oval, a square, or a rectangle.
24. The method of claim 1 , wherein the pattern has region with monotonically and smoothly varying frequency.
25. The method of claim 1 , wherein the pattern has a chirped region.