Fabrication of ceramic microstructures

Abstract

The invention provides ceramic molded solid articles and methods for making these articles on the micron scale. Articles are molded from ceramic precursors, optionally using molds including at least one portion that is elastomeric.

1 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers;    filling the mold with a ceramic precursor;    heating the ceramic precursor under a moisture-free atmosphere to produce a structure comprising a ceramic, the structure having a Young's modulus that does not change more than 10% upon heating to 1400° C. in an inert atmosphere; and    removing the mold from a product formed from the ceramic precursor.    
     
     
         2 . The method of  claim 1 , wherein the ceramic precursor comprises at least two different elements.  
     
     
         3 . The method of  claim 2 , wherein the at least two different elements are selected from a group consisting of carbon, nitrogen, boron, silicon, phosphorus, aluminum and hydrogen.  
     
     
         4 . The method of  claim 1 , wherein the ceramic precursor comprises at least three different elements.  
     
     
         5 . The method of  claim 1 , wherein each element of the ceramic structure is derived from the ceramic precursor.  
     
     
         6 . The method of  claim 1 , wherein the step of heating is performed under an inert atmosphere.  
     
     
         7 . The method of  claim 1 , wherein prior to the step of filling, the ceramic precursor is prepared to have sufficient viscosity to completely fill the mold.  
     
     
         8 . The method of  claim 7 , wherein the viscosity of the ceramic precursor is adjusted to have a value less than about 500 cm 2 /s.  
     
     
         9 . The method of  claim 1 , wherein prior to the step of filling, the mold is treated such that it is inert with respect to reaction with the ceramic precursor and any subsequent products resulting from the ceramic precursor.  
     
     
         10 . The method of  claim 9 , wherein the step of treating the mold comprises reacting the mold with an agent selected from the group consisting of alkylating, silylating, fluoroalkylating, or alkylsilylating agent.  
     
     
         11 . The method of  claim 1 , wherein the step of filling comprises positioning a surface of the mold against a surface of a substrate to create a cavity which the ceramic precursor fills.  
     
     
         12 . The method of  claim 11 , wherein the substrate is selected from the group consisting of silicon, silicon dioxide, silicon nitride, and any substrate with a smooth metallic surface.  
     
     
         13 . The method of  claim 11 , further comprising treating the substrate surface to render the substrate inert with respect to reaction with the ceramic precursor and any subsequent products resulting from the ceramic precursor.  
     
     
         14 . The method of  claim 13 , wherein the step of treating comprises silanization.  
     
     
         15 . The method of  claim 1 , wherein the step of filling comprises allowing the ceramic precursor to enter a volume of lower pressure.  
     
     
         16 . The method of  claim 1 , wherein the step of filling comprises allowing the ceramic precursor to enter a volume by means of capillary action.  
     
     
         17 . The method of  claim 1 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         18 . The method of  claim 17 , wherein the ceramic precursor is cured chemically.  
     
     
         19 . The method of  claim 17 , wherein the ceramic precursor is cured thermally.  
     
     
         20 . The method of  claim 17 , wherein the ceramic precursor is cured in the mold at a temperature of at least 100° C.  
     
     
         21 . The method of  claim 17 , wherein the ceramic precursor is cured in the mold under an inert atmosphere.  
     
     
         22 . The method of  claim 17 , wherein the precursor is cured in the mold under a moisture-free atmosphere.  
     
     
         23 . The method of  claim 1 , wherein the solution contains tetrabutylammonium fluoride.  
     
     
         24 . The method of  claim 1 , wherein the product comprises a cured ceramic precursor and after removing the mold, the method further comprises heating the cured ceramic precursor to a temperature of at least 1000° C. to produce a ceramic.  
     
     
         25 . The method of  claim 1 , further comprising transferring the product to a substrate selected from the group consisting of silicon, silicon dioxide, silicon nitride, and metal.  
     
     
         26 . The method of  claim 1 , wherein the ceramic precursor is a single precursor.  
     
     
         27 . The method of  claim 1 , wherein the ceramic precursor comprises a polymer.  
     
     
         28 . The method of  claim 1 , wherein the ceramic precursor comprises an oligomer.  
     
     
         29 . The method of  claim 1 , wherein the mold exhibits elastomeric properties.  
     
     
         30 . The method of  claim 29 , wherein the mold comprises polydialkylsiloxane material.  
     
     
         31 . The method of  claim 1 , wherein the step of filling the mold is performed under an inert atmosphere.  
     
     
         32 . The method of  claim 1 , wherein the step of filling the mold is performed under a moisture-free atmosphere.  
     
     
         33 . A method comprising: 
 providing a silanized mold having at least one component with at least one dimension less than 100 micrometers;    providing a ceramic precursor having sufficient viscosity to completely fill the mold, wherein the viscosity of the ceramic precursor is adjusted to have a value of less than about 500 cm 2 /s;    thereafter, filling the mold with the ceramic precursor; and    dissolving the filled mold.    
     
     
         34 . The method of  claim 33 , further comprising heating the ceramic precursor in the mold to produce a structure comprising a ceramic.  
     
     
         35 . The method of  claim 33 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         36 . The method of  claim 35 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         37 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers;    reacting the mold with an agent selected from the group consisting of an alkylating, silylating, fluoroalkylating, or alkylsilylating agent, such that the mold is inert with respect to reaction with a ceramic precursor and any subsequent products resulting from the ceramic precursor;    thereafter, filling the mold with the ceramic precursor; and    dissolving the filled mold.    
     
     
         38 . The method of  claim 37 , further comprising heating the ceramic precursor in the mold to produce a structure comprising a ceramic.  
     
     
         39 . The method of  claim 37 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         40 . The method of  claim 39 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         41 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers;    positioning a surface of the mold against a surface of a substrate to create a cavity which a ceramic precursor fills;    treating the substrate surface to render the substrate inert with respect to reaction with the ceramic precursor and any subsequent products resulting from the ceramic precursor; and    dissolving the mold containing the ceramic precursor.    
     
     
         42 . The method of  claim 41 , further comprising heating the ceramic precursor to produce a structure comprising a ceramic.  
     
     
         43 . The method of  claim 41 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         44 . The method of  claim 43 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         45 . A method comprising: 
 providing a silanized mold having at least one component with at least one dimension less than 100 micrometers;    allowing a ceramic precursor to enter a volume of lower pressure in the mold; and    dissolving the mold containing the ceramic precursor.    
     
     
         46 . The method of  claim 45 , further comprising heating the ceramic precursor to produce a structure comprising a ceramic.  
     
     
         47 . The method of  claim 45 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         48 . The method of  claim 47 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         49 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers;    filling the mold with a ceramic precursor;    curing the ceramic precursor in the mold under a moisture-free atmosphere; and    dissolving the mold containing the ceramic precursor.    
     
     
         50 . The method of  claim 49 , further comprising heating the ceramic precursor to produce a structure comprising a ceramic.  
     
     
         51 . The method of  claim 49 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         52 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers;    filling the mold with a ceramic precursor; and    dissolving the filled mold.    
     
     
         53 . The method of  claim 52 , further comprising heating the ceramic precursor to produce a structure comprising a ceramic.  
     
     
         54 . The method of  claim 52 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         55 . The method of  claim 54 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         56 . A method comprising: 
 providing an elastomeric mold comprising polydialkylsiloxane material having at least one component with at least one dimension less than 100 micrometers; and    filling the mold with a ceramic precursor;    heating the ceramic precursor in the mold to produce a structure comprising of a ceramic, the structure having a Young's modulus that does not change more than 10% upon heating to 1400° C. in an inert atmosphere; and    dissolving the mold containing the heated ceramic precursor.    
     
     
         57 . The method of  claim 56 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         58 . The method of  claim 57 , wherein the ceramic precursor is cured in the mold under a moisture-free atmosphere.  
     
     
         59 . A method comprising: 
 providing a mold;    silanizing the mold; and    filling the mold with a ceramic precursor.    
     
     
         60 . The method of  claim 59 , further comprising heating the ceramic precursor to produce a structure comprising a ceramic.  
     
     
         61 . The method of  claim 59 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         62 . The method of  claim 61 , wherein the ceramic precursor is cured in the mold under an inert and/or a moisture-free atmosphere.  
     
     
         63 . A method comprising: 
 providing a mold having at least one component with at least one dimension less than 100 micrometers; and    filling the mold with a ceramic precursor.    
     
     
         64 . The method of  claim 63 , wherein the ceramic precursor comprises at least two different atom types.  
     
     
         65 . The method of  claim 64 , wherein the at least two different atom types are selected from a group consisting of carbon, nitrogen, boron, silicon, phosphorus, aluminum and hydrogen.  
     
     
         66 . The method of  claim 63 , wherein the ceramic precursor comprises at least three different atom types.  
     
     
         67 . The method of  claim 63 , further comprising heating the ceramic precursor to produce a ceramic structure.  
     
     
         68 . The method of  claim 67 , wherein each atom type of the ceramic structure is derived from the ceramic precursor.  
     
     
         69 . The method of  claim 67 , wherein the step of heating is performed under an inert atmosphere.  
     
     
         70 . The method of  claim 67 , wherein the step of heating is performed under a moisture-free atmosphere.  
     
     
         71 . The method of  claim 63 , wherein prior to the step of filling, the ceramic precursor is prepared to have sufficient viscosity to completely fill the mold.  
     
     
         72 . The method of  claim 71 , wherein the viscosity of the ceramic precursor is adjusted to have a value less than about 500 cm 2 /s.  
     
     
         73 . The method of  claim 63 , wherein prior to the step of filling, the mold is treated such that it is inert with respect to reaction with the ceramic precursor and any subsequent products resulting from the ceramic precursor.  
     
     
         74 . The method of  claim 73 , wherein the step of treating the mold comprises reacting the mold with an agent selected from the group consisting of alkylating, silylating, fluoroalkylating, or alkylsilylating agent.  
     
     
         75 . The method of  claim 63 , wherein the step of filling comprises positioning a surface of the mold against a surface of a substrate to create a cavity which the ceramic precursor fills.  
     
     
         76 . The method of  claim 75 , wherein the substrate is selected from the group consisting of silicon, silicon dioxide, silicon nitride, and any substrate with a smooth metallic surface.  
     
     
         77 . The method of  claim 75 , further comprising treating the substrate surface to render the substrate inert with respect to reaction with the ceramic precursor and any subsequent products resulting from the ceramic precursor  
     
     
         78 . The method of  claim 77 , wherein the step of treating comprises silanization.  
     
     
         79 . The method of  claim 63 , wherein the step of filling comprises allowing the ceramic precursor to enter a volume of lower pressure.  
     
     
         80 . The method of  claim 63 , wherein the step of filling comprises allowing the ceramic precursor to enter a volume by means of capillary action.  
     
     
         81 . The method of  claim 63 , further comprising the step of curing the ceramic precursor in the mold.  
     
     
         82 . The method of  claim 81 , wherein the ceramic precursor is cured chemically.  
     
     
         83 . The method of  claim 81 , wherein the ceramic precursor is cured thermally.  
     
     
         84 . The method of  claim 81 , wherein the ceramic precursor is cured in the mold at a temperature of at least 100° C.  
     
     
         85 . The method of  claim 81 , wherein the ceramic precursor is cured in the mold under an inert atmosphere.  
     
     
         86 . The method of  claim 81 , wherein the precursor is cured in the mold under a moisture-free atmosphere.  
     
     
         87 . The method of  claim 63 , further comprising removing the mold from a product formed from the ceramic precursor.  
     
     
         88 . The method of  claim 87 , wherein the step of removing the mold comprises physically removing the mold.  
     
     
         89 . The method of  claim 87 , wherein the step of removing the mold comprises dissolving the mold.  
     
     
         90 . The method of  claim 89 , wherein the step of dissolving comprises dissolving the mold in a solution containing fluoride anions.  
     
     
         91 . The method of  claim 90 , wherein the solution contains tetrabutylammonium fluoride.  
     
     
         92 . The method of  claim 87 , wherein the product comprises a cured ceramic precursor and after removing the mold, the method further comprises heating the cured ceramic precursor to a temperature of at least 1000° C. to produce a ceramic.  
     
     
         93 . The method of  claim 87 , further comprising transferring the product to a substrate selected from the group consisting of silicon, silicon dioxide, silicon nitride, and metal.  
     
     
         94 . The method of  claim 63 , wherein the ceramic precursor is a single precursor.  
     
     
         95 . The method of  claim 63 , wherein the ceramic precursor comprises a polymer.  
     
     
         96 . The method of  claim 63 , wherein the ceramic precursor comprises an oligomer.  
     
     
         97 . The method of  claim 63 , wherein the mold exhibits elastomeric properties.  
     
     
         98 . The method of  claim 97 , wherein the mold comprises polydialkylsiloxane material.  
     
     
         99 . The method of  claim 63 , wherein the step of filling the mold is performed under an inert atmosphere.  
     
     
         100 . The method of  claim 63 , wherein the step of filling the mold is performed under a moisture-free atmosphere.  
     
     
         101 . An article comprising a free standing ceramic structure with at least one component with a dimension less than 50 micrometers, the at least one component being integral with the article.  
     
     
         102 . The article of  claim 101 , wherein the article is a molded article.  
     
     
         103 . The article of  claim 101 , wherein the ceramic comprises a formula Si w B x N y C z .  
     
     
         104 . The article of  claim 101 , wherein the ceramic has an oxide content of less than about 30% by atomic composition.  
     
     
         105 . The article of  claim 101 , wherein the ceramic is substantially free of structural degradation upon exposure to air at a temperature of greater than 1000° C. for at least 2 hours.  
     
     
         106 . The article of  claim 101 , wherein the at least one component has an aspect ratio of at least about 2:1.  
     
     
         107 . The article of  claim 101 , wherein the at least one component has an aspect ratio of at least about 4:1.  
     
     
         108 . The article of  claim 101 , wherein the article is capable of withstanding temperatures greater than 2000° C.  
     
     
         109 . The article of  claim 101 , wherein the article can withstand temperatures less than 1500° C. in the presence of air for at least about 80 hours resulting in a change of less than a 10% in Young's Modulus of the article.  
     
     
         110 . The article of  claim 101 , wherein the at least one component has a dimension less than 25 micrometers, the at least one component being integral with the article.  
     
     
         111 . The article of  claim 101 , wherein the at least one component has a dimension less than 15 micrometers, the at least one component being integral with the article.  
     
     
         112 . A method comprising: 
 providing a mold;    filling the mold with a ceramic precursor; and    dissolving the mold.