Semiconductor processing by magnetic field guided etching

Patent metadata

Field	Value
Publication number	US-9281206-B2
Application number	US-201214351690-A
Country	US
Kind code	B2
Filing date	Oct 12, 2012
Priority date	Oct 12, 2011
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

Methods, systems, and devices are described for slicing and shaping materials using magnetically guided chemical etching. In one aspect, a method includes forming a pattern on a substrate by a mask, depositing a catalytic etcher layer on the patterned substrate, a magnetic guide layer on the etcher layer, and a protection layer on the guide layer, etching the substrate by applying an etching solution to the substrate that chemically reacts with the etcher layer and etches material from the substrate at exposed regions not covered by the mask, steering the composite etching structure into the substrate during the etching by an applied magnetic field that creates a force on the guide layer to direct the etching, in which the steering defines the shape of the sliced regions of the etched substrate, and removing the etched material, the mask, and the composite etching structure to produce a sliced material structure.

First claim

What is claimed is:

1. A method for guided electroless etching to form a cut in a material, comprising:
forming a patterned mask on a substrate to partially cover the surface of the substrate while exposing one or more selected regions on the surface of the substrate to be removed by etching;
depositing an etcher layer of a first catalyst material on each exposed surface of the selected regions of the substrate, a guide layer of a magnetic material on the etcher layer, and a protection layer of a second catalyst material on the guide layer, wherein the etcher layer, guide layer and protection layer form a composite etching structure;
etching the substrate by applying an etching solution to the substrate that chemically reacts with the etcher layer and etches material from the substrate at each selected region not covered by the patterned mask to form a sliced region;
steering the composite etching structure into the substrate during the etching by an applied magnetic field that creates a force on the guide layer to direct a direction of the etching, wherein the steering defines the shape of the sliced region of the etched substrate; and
removing the etched material, the patterned mask, and the composite etching structure from the substrate to produce a sliced material structure.

2. The method of claim 1 , wherein the forming the patterned mask includes depositing a resist layer to form the mask using lithographic techniques selected from photolithography, deep ultraviolet (UV) lithography, extreme UV lithography, nano-imprint lithography, ink jet printing lithography, shadow mask patterning, or electron beam lithography.

3. The method of claim 1 , wherein the depositing the etcher layer, the guide layer, and the protection layer includes using one of thermal evaporation, sputtering, ion beam deposition, pulsed laser deposition, chemical vapor deposition, electroplating, or electroless plating processes.

4. The method of claim 1 , wherein the etching solution includes at least one of hydrofluoric acid (HF), hydrogen peroxide (H 2 O 2 ), nitric acid (HNO 3 ), ammonium fluoride (NH 4 F), water (H 2 O), sodium hydroxide (NaOH), or potassium hydroxide (KOH).

5. The method of claim 1 , wherein the applying the etching solution includes immersing the substrate having the formed pattern and deposited layers into a container containing the etching solution.

6. The method of claim 5 , comprising controlling the level of etching solution in the container.

7. The method of claim 1 , wherein the applied magnetic field produces a magnetostatic attractive force on the magnetic material that accelerates a descending speed of the first catalyst material to etch the substrate.

8. The method of claim 1 , wherein the sliced region is formed along an axis not aligned with the crystallographic orientation of the substrate.

9. The method of claim 1 , wherein the first and second catalyst materials include at least one of gold (Au), Au-containing alloy, platinum (Pt), Pt-containing alloy, palladium (Pd), Pd-containing alloy, silver (Ag), or Ag-containing alloy.

10. The method of claim 9 , wherein the first catalyst material and the second catalyst material are the same material.

11. The method of claim 1 , wherein the magnetic material includes at least one of iron (Fe), Fe-containing alloy, cobalt (Co), Co-containing alloy, nickel (Ni), or Ni-containing alloy.

12. The method of claim 1 , wherein the magnetic material includes at least one of a CoPt intermetallic compound, FePt intermetallic compound, CoPd intermetallic compound, Sm—Co permanent magnet alloy, Nd—Fe—B permanent magnet alloy, or ferrite oxide magnet.

13. The method of claim 1 , wherein the etcher layer and the guide layer include a relative geometry selected from a hidden magnetic layer sandwich configuration, enveloped magnetic layer configuration, embedded island magnetic material configuration, or porous catalyst and porous magnetic material layered configuration.

14. The method of claim 1 , wherein the substrate includes at least one of silicon or germanium.

15. The method of claim 1 , wherein the pattern includes line patterns, rectangle patterns, circular patterns, curved patterns, or irregular patterns.

16. The method of claim 1 , wherein the sliced material structure is formed of silicon and includes a thickness of 5 μm or less, wherein the silicon sliced material structure is a flexible material.

17. The method of claim 16 , wherein the sliced material structure is implemented in a device including one of a flexible display, a sensor, or an actuator.

18. The method of claim 1 , wherein the composite etching structure includes pores in each of the etcher layer, the guide layer, and the protection layer such that the sliced region is etched with an increased depth.

19. The method of claim 18 , wherein the sliced region of the sliced material structure forms needle or pillar structures of a diameter of 10 μm or less and a height of 300 μm or greater.

20. The method of claim 19 , wherein the sliced material structure is implemented in a device including one of a solar cell, a sensor probe, or a battery electrode.

21. The method of claim 1 , wherein the sliced region is completely etched through the substrate to produce a plurality of uncoupled sliced material structures.

22. The method of claim 1 , wherein the sliced region is partially etched into the substrate to produce an array of aligned pillar or sheet structures.

23. The method of claim 22 , wherein the sliced material structure including the aligned pillar or sheet structures is implemented in a device including a photovoltaic solar cell structure, the photovoltaic solar cell structure comprising a doped surface over the aligned pillar or sheet structures to provide photovoltaic reactions, and an optically transparent planarized filler material between adjacent aligned pillar or sheet structures.

24. The method of claim 23 , wherein the photovoltaic solar cell structure further comprises an optically transparent conducting oxide on an upper surface, and electronic circuitry on the optically transparent conducting oxide.

25. The method of claim 1 , wherein the applying the etching solution includes tilting the substrate having the formed pattern and deposited layers and pouring the etching solution over the tilted substrate with a controlled pour rate.

26. The method of claim 25 , wherein the etching solution includes a depth above the upper surface of the sliced region of less than 5 mm.

27. The method of claim 1 , wherein the applied magnetic field is generated by one of a magnet or electromagnet.

28. The method of claim 27 , wherein the magnet or electromagnet is positioned above the substrate and the force is a repulsive force that pushes the composite etching structure into the substrate during etching.

29. The method of claim 27 , wherein the magnet includes two laterally positioned magnets.

30. The method of claim 27 , wherein the electromagnet includes two laterally positioned electromagnets.

31. A method for guided electroless etching to slice and shape a material, comprising:
forming a patterned mask on a substrate to partially cover the surface of the substrate while exposing one or more selected regions on the surface of the substrate to be removed by etching;
depositing an etcher layer o

Assignees

• Univ California

Inventors

• Jin Sungho
• Oh Young
• Choi Chulmin
• Hong Dae-Hoon
• Kim Tae Kyoung

Classifications

• H10P72/0426

  with the semiconductor substrates being dipped in baths or vessels · CPC title

• H10P50/642

  Chemical etching · CPC title

• H10P50/644 Primary

  Anisotropic liquid etching (H10P50/61 takes precedence) · CPC title

• B28D5/00 Primary

  Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor (working by grinding or polishing B24; for artistic purposes B44B) · CPC title

• H10F77/707

  of the substrates or of layers on substrates, e.g. textured ITO layer on a glass substrate · CPC title