Designer particles of micron and submicron dimension

Abstract

Micron-sized particles are produced in quantity by one of various methods, including generally the steps of preparing a substrate surface through a lithographic process, the surface being characterized by defining a plurality of elements, depositing a layer of particle material on the substrate surface including the elements, processing the substrate surface to isolate the material deposited on the elements, and separating the particles from the elements. The size and shape of the elements predetermine the size and shape of the particles. The elements may comprise, inter alia, pillars of photoresist or spaces on the substrate surrounded and defined by photoresist.

What is claimed is:  
     
         1 . An array comprised of a plurality of discrete particles on a substrate, said particles being separable from said substrate and between about 0.1 microns and about 25 microns in width  
     
     
         2 . The array of  claim 1  wherein said particles are substantially uniformly sized and substantially uniformly shaped.  
     
     
         3 . The array of  claim 2  wherein the particles are separable from said substrate by removing that portion of said substrate which attaches each of said particles to said substrate.  
     
     
         4 . The array of  claim 3  wherein said removable portion of said substrate is removable by dissolving said substrate.  
     
     
         5 . The array of  claim 2  wherein the particles are separable from said substrate by vibration.  
     
     
         6 . The array of  claim 2  wherein the particles are separable from said substrate by mechanically separating said particles from the portion of substrate which attaches each of said particles to said substrate.  
     
     
         7 . The array of  claim 2  wherein said particles comprise at least one deposited layer of a desired particle forming substance on said substrate.  
     
     
         8 . The array of  claim 2  wherein said substrate is multi-level, with the particles being formed on only one of the levels of said multi-level substrate.  
     
     
         9 . The array of  claim 8  wherein said particles are formed on a top level of said substrate.  
     
     
         10 . The array of  claim 8  wherein said particles are formed on a level of said substrate below a top level of said substrate.  
     
     
         11 . The array of  claim 2  wherein said particles are comprised of a plurality of layers of different materials.  
     
     
         12 . The array of  claim 2  wherein said particles are comprised of one or more materials chosen from the group: metals, insulators, semiconductors, ceramics, and glasses.  
     
     
         13 . The array of  claim 11  wherein each of said layers is a deposited layer of material.  
     
     
         14 . The array of  claim 2  wherein each of said particles is magnetizable.  
     
     
         15 . The array of  claim 2  wherein each of said particles is magnetized.  
     
     
         16 . The array of  claim 2  wherein each of said particles is disk-shaped.  
     
     
         17 . The array of  claim 2  wherein each of said particles has an internal surface area when separated from said substrate.  
     
     
         18 . The array of  claim 17  wherein said internal surface area comprises a generally circular opening in said particle.  
     
     
         19 . The array of  claim 2  wherein said particles are substantially uniformly spaced across a surface of the array.  
     
     
         20 . The array of  claim 19  wherein said substrate comprises a wafer, said wafer including a layer of resist, said particles being layered on top of said resist layer.  
     
     
         21 . The array of  claim 20  wherein said layer of resist comprises a plurality of separated elements each of said elements being of a size and shape as desired for each of the particles.  
     
     
         22 . The array of  claim 21  wherein said elements are the residue from a lithographic process.  
     
     
         23 . The array of  claim 22  wherein said elements are the residue from a photolithographic process.  
     
     
         24 . The array of  claim 23  wherein said elements are soluble in solutions for which the particles are non-soluble so that the particles are thereby separable from said substrate.  
     
     
         25 . A silicon wafer substrate includes a layer of photoresist residue comprised of a plurality of substantially uniformly sized, substantially uniformly shaped elements spaced substantially uniformly across at least a portion of a surface of the substrate, each of said elements having a particle layered on top thereof, and said photoresist being soluble in solutions for which the particles are non-soluble so that the particles are thereby separable from said substrate by immersion in a solution.  
     
     
         26 . The silicon wafer of  claim 25  wherein said particles are multi-layered with different layers of dissimilar deposited material forming said layers.  
     
     
         27 . The silicon wafer of  claim 26  wherein the particles are between about 0.1 microns and about 25 microns in width.  
     
     
         28 . A silicon wafer substrate includes a layer of photoresist residue comprised of a pattern defining a plurality of substantially uniformly sized, substantially uniformly shaped elements spaced substantially uniformly across at least a portion of a surface of the substrate, each of said elements having a particle layered on top thereof, and said photoresist being soluble in solutions for which the particles are non-soluble so that the pattern is thereby separable from said substrate by immersion in a solution, leaving the particles in place on said elements.  
     
     
         29 . The silicon wafer substrate of  claim 28  wherein the particles are between about 0.1 microns and about 25 microns in width.  
     
     
         30 . The silicon wafer substrate of  claim 29  wherein said particles are multi-layered with different layers of dissimilar deposited material forming said layers.  
     
     
         31 . A silicon wafer substrate includes a sacrificial layer of a first material upon which is deposited a layer of particle material, the particle material layer having a layer of photoresist residue comprised of a plurality of substantially uniformly sized, uniformly shaped elements spaced substantially uniformly across at least a portion of a surface of the substrate to protect a similarly sized and shaped particle thereunder during an etching process which removes the surrounding portion of particle layer to thereby form a plurality of particles on said substrate, said particles being separable from said substrate by dissolving the sacrificial layer.  
     
     
         32 . The silicon wafer substrate of  claim 31  wherein the particles are between about 0.1 microns and about 25 microns in width.  
     
     
         33 . The silicon wafer substrate of  claim 32  wherein said particles are multi-layered with different layers of dissimilar deposited material forming said layers.  
     
     
         34 . A method for forming a plurality of particles having a predetermined shape and a size between about 0.1 microns and about 25 microns, said method comprising the steps of: 
 a. preparing a substrate,    b. depositing at least one layer of a particle material on said substrate, and    c. separating the particles from said substrate.    
     
     
         35 . The method of  claim 34  wherein the step of preparing the substrate includes the step of patterning the substrate with a lithographic process.  
     
     
         36 . The method of  claim 35  wherein the step of depositing the particle layer material includes the step of metal deposition.  
     
     
         37 . The method of  claim 36  wherein the step of preparing the substrate includes the step of patterning a wafer.  
     
     
         38 . The method of  claim 37  wherein the step of patterning the wafer includes the steps of applying a layer of photoresist to a base, and processing the photoresist to create a pattern on said base to define the surfaces for receiving the deposited layer of particle material.  
     
     
         39 . The method of  claim 38  wherein the step of processing the photoresist includes the steps of preparing a mask and exposing the layer of photoresist through the mask.  
     
     
         40 . The method of  claim 39  wherein the step of separating the particles includes the step of dissolving the photoresist which attaches the particles to the base.  
     
     
         41 . The method of  claim 40  wherein the step of separating the particles includes the step of vibrating the wafer.  
     
     
         42 . The method of  claim 39  wherein the step of separating the particles includes the step of vibrating the wafer.  
     
     
         43 . The method of  claim 39  wherein the step of preparing a mask includes the step of preparing a mask which creates a pattern of pillars of photoresist which define the size and shape of the particles.  
     
     
         44 . The method of  claim 39  wherein the step of preparing a mask includes the step of preparing a mask which creates a pattern of photoresist that defines a plurality of spaces in said photoresist which define the size and shape of the particles.  
     
     
         45 . A method for making a plurality of particles, each of said particles having a predetermined size between about 0.1 microns and about 25 microns, and a predetermined shape, and said particles being substantially uniformly sized and substantially uniformly shaped, the method comprising the steps of: preparing a substrate comprising a base with a layer of photoresist thereon, said photoresist being patterned to form a plurality of elements which define the size and shape of the particles, depositing at least one layer of particle material on said substrate, said elements receiving said particle material to thereby form said particles, and removing said particles from said substrate.  
     
     
         46 . The method of  claim 45  wherein said photoresist forms the elements and the particle material is deposited thereon to form said particles.  
     
     
         47 . The method of  claim 45  wherein said photoresist surrounds and defines said elements and the particle material is deposited on said base.  
     
     
         48 . A method for making a plurality of particles, each of said particles having a predetermined size between about 0.1 microns and about 25 microns, and a predetermined shape, and said particles being substantially uniformly sized and substantially uniformly shaped, the method comprising the steps of: preparing a substrate comprising a base, depositing a sacrificial layer on said base, depositing at least one layer of particle material on said substrate, depositing a layer of photoresist on said layer of particle material, said photoresist being patterned to form a plurality of elements which define the size and shape of the particles, removing the particle layer surrounding the pattern of photoresist to thereby form the particles under the remaining photoresist, and removing said particles from said substrate.  
     
     
         49 . The method of  claim 48  wherein the step of removing the particles includes the step of dissolving the sacrificial layer.  
     
     
         50 . The method of  claim 49  wherein the step of removing the particle layer surrounding the pattern of photoresist includes the step of etching the exposed particle layer.  
     
     
         51 . The method of  claim 50  wherein the step of removing the particles includes the step of vibrating the substrate.  
     
     
         52 . An array comprised of a plurality of discrete particles on a substrate, said particles being between about 0.01 microns and about 0.1 microns in width.  
     
     
         53 . The array of  claim 52  wherein said particles are substantially uniformly sized and substantially uniformly shaped.  
     
     
         54 . The array of  claim 53  wherein the particles are separable from said substrate by removing that portion of said substrate which attaches each of said particles to said substrate.  
     
     
         55 . The array of  claim 54  wherein said particles comprise at least one deposited layer of a desired particle forming substrate on said substrate.  
     
     
         56 . A method for forming a plurality of particles having a predetermined shape and a size between about 0.01 microns and about 0.1 microns, said method comprising the steps of: 
 a. preparing a substrate,    b. depositing at least one layer of particle material on said substrate, and    c. separating the particles from said substrate.    
     
     
         57 . The method of  claim 56  wherein the step of preparing the substrate includes the step of patterning the substrate with a lithographic process.  
     
     
         58 . The method of  claim 57  wherein the step of depositing the particle layer material includes the step of metal deposition.  
     
     
         59 . The method of  claim 58  wherein the step of preparing the substrate includes the step of patterning a wafer.  
     
     
         60 . The method of  claim 59  wherein the step of patterning the wafer includes the steps of applying a layer of photoresist to a base, and processing the photoresist to create a pattern on said base to define the surfaces for receiving the deposited layer of particle material.