Method of manufacturing microneedle

Abstract

The invention discloses a method of manufacturing a microneedle including the steps of forming an island etching mask having thickness distribution on a substrate, and processing the substrate into a needle by taking advantage of a difference in etching rates between the etching mask and the substrate. The invention enables to readily control a point angle and height of the manufactured needle.

1 - 7 . (canceled) 
   
   
       8 . A method of manufacturing a microneedle, comprising:
 forming an array of island etching masks on a substrate;   deforming the etching masks so as to have thickness distribution; and   processing the substrate into needles by taking advantage of the difference in etching rates between the etching masks and the substrate.   
   
   
       9 . The method of manufacturing the microneedle according to  claim 8 , wherein the island etching masks formed on the substrate are deformed so as to have thickness distribution by allowing the etching masks to reflow. 
   
   
       10 . The method of manufacturing the microneedle according to  claim 8 , wherein the island etching masks are formed on the substrate by ejecting a droplets prepared by dissolving an etching mask material in a solvent or by ejecting a droplets prepared by heating and melting the etching mask material, and the etching masks are deformed so as to have thickness distribution by allowing the solvent to evaporate or by allowing the etching mask material to solidify. 
   
   
       11 . The method of manufacturing the microneedle according to  claim 8 , comprising:
 forming holes on the substrate;   filling the holes with a filler;   forming an array of island etching masks on a side of the substrate where the holes are formed; followed by deforming the etching masks so as to have thickness distribution;   etching the substrate to process into needles; and   removing the filler.   
   
   
       12 . The method of manufacturing the microneedle according to  claim 8 , comprising:
 forming non-penetrated holes on the substrate;   forming an array of island etching masks on a side of the substrate opposed to the side where the non-penetrated holes formed, followed by deforming the etching masks so as to have thickness distribution; and   etching the substrate to process into needles.   
   
   
       13 . The method of manufacturing the microneedle according to  claim 11 , wherein the holes are penetrated holes or non-penetrated holes. 
   
   
       14 . The method of manufacturing the microneedle according to  claim 11 , wherein positions of the etching masks are aligned with positions of the holes. 
   
   
       15 . The method of manufacturing the microneedle according to  claim 11 , wherein positions of the etching masks are displaced from positions of the holes. 
   
   
       16 . The method of manufacturing the microneedle according to  claim 8 , wherein the etching masks are formed into a shape having an inwardly depressed part at a periphery. 
   
   
       17 . The method of manufacturing the microneedle according to  claim 8 , wherein an etching selectivity ratio defined by dividing the etching rate of the substrate by the etching rate of the etching masks is set to 1 or more and 100 or less. 
   
   
       18 . The method of manufacturing the microneedle according to  claim 8 , wherein an etching condition is changed so that an etching selectivity ratio is changed on the way of etching. 
   
   
       19 . (canceled) 
   
   
       20 . The method of manufacturing the microneedle according to  claim 8 , wherein the etching is anisotropic etching. 
   
   
       21 . The method of manufacturing the microneedle according to  claim 20 , wherein the anisotropic etching is ion etching, reactive ion etching, ion-beam etching or reactive ion-beam etching. 
   
   
       22 . The method of manufacturing the microneedle according to  claim 8 , wherein after the microneedle is formed the microneedle is subjected to isotropic etching. 
   
   
       23 . A method of manufacturing a replica mold for manufacturing a microneedle, comprising performing transcription using the microneedle manufactured by the method according to  claim 8  as a master mold. 
   
   
       24 . The method of manufacturing the replica mold for manufacturing the microneedle according to  claim 23 , wherein the transcription is performed by using a plated metal, resin or ceramic. 
   
   
       25 . A microneedle manufactured by the method according to  claim 8 . 
   
   
       26 . A microneedle wherein the microneedle is manufactured by using the replica mold for manufacturing the microneedle manufactured by the method according to  claim 23 . 
   
   
       27 . The microneedle according to  claim 26 , wherein the microneedle is formed of a biocompatible material. 
   
   
       28 . The method of manufacturing the microneedle according to  claim 12 , wherein a position of the etching mask is aligned with a position of the hole. 
   
   
       29 . The method of manufacturing the microneedle according to  claim 12 , wherein a position of the etching mask is displaced from a position of the hole.