Nozzle plate containing multiple micro-orifices for cascade impactor and method for manufacturing the same

Abstract

A nozzle plate containing multiple micro-orifices for the cascade impactor and a method for manufacturing the same are disclosed. The nozzle plate is formed by a series of semiconductor processes, including lithography, etching and electroplating. The nozzle plate comprises a plate body and a plurality of micro-orifices formed on the plate body. The orifice has a diameter which gradually expands in the direction away from the bottom of the plate body to achieve a smooth inner surface, allowing particles to pass therethrough smoothly without being clogged in the nozzle plate.

1 . A nozzle plate for a multi-stage cascade impactor, comprising:
 a plate body; and   a plurality of micro-orifices formed on the said plate body and cutting through top and bottom sides of the said plate body, each said micro-orifice having a smooth inner surface and a diameter expanding gradually in direction from the bottom side of said the plate body toward the top side thereof.   
     
     
         2 . The nozzle plate as claimed in  claim 1 , wherein the number of the said micro-orifices is within 50-10000. 
     
     
         3 . The nozzle plate as claimed in  claim 1 , wherein the number of the said micro-orifices is within 900-2000. 
     
     
         4 . The nozzle plate as claimed in  claim 1 , further comprising a plurality of annular protrusions protruded from the bottom side of said plate body around each said micro-orifice. 
     
     
         5 . The nozzle plate as claimed in  claim 1 , wherein the diameter of each said micro-orifice at the bottom side of said plate body is within 45-410 μm. 
     
     
         6 . A method for making a nozzle plate containing multiple micro-orifices, comprising the steps of:
 (1) depositing a seed layer on a substrate;   (2) coating the said seed layer with a layer of first photoresist, radiating UV light through a first mask onto said first photoresist, and then developing the first photoresist;   (3) etching said seed layer and removing the said first photoresist, so as to form a plurality of through holes on said seed layer that cut through top and bottom sides of said seed layer;   (4) coating a sacrificial layer on said substrate and said seed layer;   (5) depositing a metal mask film on said sacrificial layer;   (6) coating a layer of second photoresist on the said metal mask film, radiating UV light through a second mask onto the said second photoresist, and then developing the second photoresist;   (7) etching the said metal mask film and removing the said second photoresist, so as to form a plurality protrusions on the said sacrificial layer;   (8) etching the said sacrificial layer until said substrate and the said seed layer are exposed to the outside;   (9) electroplating a metal material onto the said seed layer; and   (10) removing the said substrate, the said seed layer and the said sacrificial layer.   
     
     
         7 . The method for making a nozzle plate containing multiple micro-orifices as claimed in  claim 6 , wherein the metal material used during step (9) is a mix of nickel and cobalt.