Process condition sensing device and method for plasma chamber

Abstract

A sensing device for measuring a plasma process parameter in a plasma chamber for processing workpieces may include a substrate with one or more sensor embedded in the substrate. The substrate can have a surface made of substantially the same material as workpieces that are plasma processed in the plasma chamber. Each sensor can include a collector portion made of substantially the same material as the substrate surface. The collector portion includes a surface that is level with the surface of the substrate. Sensor electronics are embedded into the substrate and coupled to the collector portion. When the substrate surface is exposed to a plasma one or more signals resulting from the plasma can be measured with the sensor(s).

What is claimed is: 
     
         1 . A sensing device for measuring plasma process parameters in a plasma chamber for processing workpieces, the sensing device comprising:
 a substrate made of a material that is substantially the same material as workpieces that are processed by a plasma in the plasma chamber;   one or more sensors embedded in the substrate, wherein each sensor comprises a collector portion made of substantially the same material as the substrate, wherein the collector portion includes a surface that is coplanar with a top surface of the substrate; and   sensor electronics embedded into the substrate and coupled to the collector portion.   
     
     
         2 . The device of  claim 1 , further comprising a direct current (DC) connection between the collector portion and the substrate. 
     
     
         3 . The device of  claim 1  wherein a cavity is formed in the substrate and the collector portion is disposed in the cavity and electrically insulated from the substrate. 
     
     
         4 . The device of  claim 1  wherein the substrate includes a first layer and a second layer, wherein the sensor electronics are sandwiched between the first and second layers. 
     
     
         5 . The device of  claim 4  wherein the first and second layers are made of conductive or semiconducting material, wherein the sensor electronics are electrically insulated from the first and second layers. 
     
     
         6 . The device of  claim 4  wherein the substrate surface and the collector portion are formed from the first layer, wherein the collector portion is electrically insulated from a remaining portion of the first layer. 
     
     
         7 . The device of  claim 1  wherein the substrate is made in on or more layers comprising silicon wafers with a diameter of between 100 mm and 450 mm and the sensing device has a thickness of 0.3 mm to 10 mm. 
     
     
         8 . The sensing device of  claim 1  wherein the substrate is made of substantially the same material as a semiconductor wafer, lithography mask substrate, or flat panel display substrate. 
     
     
         9 . The sensing device of  claim 8  wherein the surface of the substrate includes a photoresist top layer. 
     
     
         10 . The sensing device of  claim 1  wherein the collector portion is the top surface of the substrate. 
     
     
         11 . The sensing device of  claim 10  wherein the substrate includes an electrically insulating layer sandwiched between a resistive layer that forms the collector portion and an electrically conductive layer. 
     
     
         12 . The sensing device of  claim 11  further comprising one or more electrically conductive sensor contacts formed on an underside of the resistive layer. 
     
     
         13 . The sensing device of  claim 12 , wherein the electronics include DC sensor electronics electrically coupled the one or more electrically conductive sensor contacts. 
     
     
         14 . The sensing device of  claim 12 , wherein the electronics include AC sensor electronics electrically coupled to the one or more electrically conductive sensor contacts. 
     
     
         15 . The sensing device of  claim 12  wherein the electronics are sandwiched between the conductive layer and another conductive layer and electrically coupled to the one or more electrically conductive sensor contacts. 
     
     
         16 . The sensing device of  claim 1  wherein a top surface of the substrate is planar and has a profile that is substantially the same as a standard process substrate. 
     
     
         17 . The sensing device of  claim 1  wherein the one or more sensors include one or more pairs of collector portions and wherein the collector portions and sensor electronics are configured to operate as dual or triple differential Langmuir probes. 
     
     
         18 . The sensing device of  claim 1  wherein the electronics include signal conditioning electronics and signal processing electronics. 
     
     
         19 . The sensing device of  claim 18  wherein the circuits are formed onto a polyimide flexible substrate. 
     
     
         20 . The sensing device of  claim 18  wherein the circuits are formed directly on the substrate or a layer of the substrate. 
     
     
         21 . The sensing device of  claim 1  wherein the electronics for each sensor includes a local digital processor. 
     
     
         22 . The sensing device of  claim 21  further comprising a centralized communication unit or processor coupled to each local digital processor. 
     
     
         23 . The sensing device of  claim 1  further comprising a material on the surface of the collector portion includes, wherein the material alters an interaction between the collector portion and the plasma.