Particulate matter sensor unit

Abstract

A particulate matter (PM) sensor unit may include an exhaust line where exhaust gas passes, and a PM sensor that may be disposed at one side of the exhaust line and that generates a signal when particulate matter included in the exhaust gas passes the vicinity thereof, wherein the PM sensor may be an electrostatic induction type that generates an induction charge while the particulate matter having an electric charge passes the vicinity thereof.

What is claimed is: 
     
         1 . A particulate matter (PM) sensor unit, comprising:
 an exhaust line where exhaust gas passes; and   a PM sensor that is disposed at one side of the exhaust line and that generates a signal when particulate matter included in the exhaust gas passes the vicinity thereof,   wherein the PM sensor is an electrostatic induction type that generates an induction charge while the particulate matter having an electric charge passes the vicinity thereof.   
     
     
         2 . The particulate matter sensor unit of  claim 1 , wherein the PM sensor includes:
 protrusions that protrude on a front surface portion of the PM sensor and are arranged with a predetermined width gap and a predetermined length gap therebetween;   a heater electrode that is formed on a rear surface portion thereof to generate heat through a supplied current and that burns the particulate matter attached to the front surface portion; and   a sensing electrode pad that is formed adjacent to the heater electrode to transmit the signal to the outside.   
     
     
         3 . The particulate matter sensor unit of  claim 2 , wherein the heater electrode includes a portion that is formed as a zigzag shape. 
     
     
         4 . The particulate matter sensor unit of  claim 2 , wherein the PM sensor includes:
 a silicone electrode layer; and   an insulating layer that is formed on a front surface portion and a rear surface portion of the silicone electrode layer to cover the silicone electrode layer,   wherein a protruding electrode is formed on the front surface portion of the silicone electrode layer corresponding to the protrusions, and the insulating layer has a predetermined thickness to cover the protruding electrode.   
     
     
         5 . The particulate matter sensor unit of  claim 4 , wherein the insulating layer is not formed on the rear surface portion of the silicone electrode layer where the sensing electrode pad is formed. 
     
     
         6 . The particulate matter sensor unit of  claim 4 , wherein the insulating layer includes an oxide layer covering the silicone electrode layer, and a nitride layer covering the oxide layer. 
     
     
         7 . The particulate matter sensor unit of  claim 2 , wherein the shape of the protrusion has one shape of a cuboid, a regular hexahedron, a sphere, a triangular pyramid, a quadrangular pyramid, and a cone. 
     
     
         8 . A manufacturing method of a particulate matter sensor unit, comprising:
 cleaning a silicone electrode layer;   forming an etching prevention layer on an entire front surface portion of the silicone electrode layer;   eliminating a regular pattern from the etching prevention layer;   etching a front surface portion of the silicone electrode layer through the eliminated portion of the etching prevention layer to a predetermined depth;   forming a protruding electrode by eliminating the etching prevention layer;   forming an insulation layer on an entire front surface portion and rear surface portion to cover the protruding electrode;   selectively eliminating a part where a sensing electrode pad is formed in the insulating layer that is formed on the rear surface portion of the silicone electrode layer;   forming a PR layer of which a patterned part thereof is eliminated corresponding to a heat electrode on the entire rear surface portion of the silicone electrode layer;   forming a Pt layer on the PR layer and the silicone electrode layer; and   forming the sensing electrode pad and the heater electrode that are formed by the Pt layer on the silicone electrode layer by eliminating the PR layer.   
     
     
         9 . The manufacturing method of  claim 8 , wherein the etching prevention layer is formed by deposing a TEOS component or sputtering Al. 
     
     
         10 . The manufacturing method of  claim 8 , wherein when the predetermined pattern is eliminated from the etching prevention layer, a patterned mask is used to selectively expose the etching prevention layer to light, and the exposed part is eliminated with an etchant. 
     
     
         11 . The manufacturing method of  claim 8 , wherein the forming the insulation layer sequentially forms an oxide layer and a nitride layer on the entire front surface portion and rear surface portion of the silicone electrode layer. 
     
     
         12 . The manufacturing method of  claim 8 , wherein a part where the patterned part of the PR layer is eliminated has a negative slope in the forming a PR layer. 
     
     
         13 . The manufacturing method of  claim 8 , wherein the Pt layer has a Pt component in the forming the Pt layer.