Capacitive humidity sensor

Abstract

Provided is a capacitive humidity sensor. The capacitive humidity sensor includes an upper electrode disposed on a first plane, a plurality of first electrodes included in the upper electrode, a plurality of second electrodes disposed between the first electrodes, and a humidity sensitive layer surrounding the second electrodes.

What is claimed is: 
     
         1 . A method of fabricating a capacitive humidity sensor, the method comprising:
 forming a first electrode and a second electrode in a sensing region over a substrate;   forming a pad electrode in a pad region over the substrate;   forming a passivation layer over the sensing region and the pad region including the pad electrode, the first electrode and the second electrode;   removing a portion of the passivation layer from the sensing region to form a first groove between the first electrode and the second electrode, and a second groove between the first electrode and the pad electrode; and   disposing a humidity sensitive layer in the first and second grooves, and   wherein the first groove extends below a bottom surface of the first electrode.   
     
     
         2 . The method of  claim 1 , further comprising forming a first protection layer over the passivation layer following the removing the portion of the passivation layer. 
     
     
         3 . The method of  claim 2 , further comprising exposing the pad electrode by removing the first protection layer and the passivation layer. 
     
     
         4 . The method of  claim 1 , wherein depth of the first groove is different from depth of the second groove. 
     
     
         5 . The method of  claim 1 , wherein the second groove is deeper than the first groove. 
     
     
         6 . The method of  claim 1 , wherein the passivation layer comprises a HDP silicon oxide layer. 
     
     
         7 . The method of  claim 1 , wherein the removing the passivation layer is performed until upper portions of the first electrode and the second electrode are formed in the curved shapes. 
     
     
         8 . The method of  claim 7 , wherein the passivation layer formed over the sensing region is completely removed. 
     
     
         9 . The method of  claim 1 , further comprising forming a second protection layer over the humidity sensitive layer. 
     
     
         10 . The method of  claim 1 , wherein the second electrode comprises discrete electrodes. 
     
     
         11 . The method of  claim 10 , wherein the humidity sensitive layer is disposed between each of a pair of adjacent discrete electrodes. 
     
     
         12 . A method of fabricating a capacitive humidity sensor, the method comprising:
 forming a lower electrode on a substrate;   forming a first insulating layer over the lower electrode;   forming a via in the first insulating layer and connected to the lower electrode;   forming an upper electrode over the lower electrode, the upper electrode comprising a first electrode and a second electrode;   forming a second insulating layer over the upper electrode;   forming a first groove between the first electrode and the second electrode, the first groove being deeper than a bottom surface of the upper electrode; and   disposing a humidity sensitive layer in the first groove deeper than the bottom surface of the upper electrode.   
     
     
         13 . The method of  claim 12 , wherein a bottom of the first groove is between the bottom surface of the upper electrode and a top surface of the lower electrode. 
     
     
         14 . The method of  claim 12 , further comprising forming a first protection layer over the humidity sensitive layer. 
     
     
         15 . The method of  claim 12 , further comprising forming a pad electrode adjacent to the upper electrode; and
 forming a second groove between the first electrode and the pad electrode.   
     
     
         16 . The method of  claim 15 , wherein the second groove is deeper than the first groove. 
     
     
         17 . The method of  claim 12 , wherein the second electrode comprises discrete electrodes. 
     
     
         18 . The method of  claim 17 , wherein the humidity sensitive layer is disposed between each of a pair of adjacent discrete electrodes. 
     
     
         19 . The method of  claim 17 , wherein the discrete electrodes are not connected to each other on a plane having the first electrode.