Hot plate and method of producing the same

Abstract

An object of the present invention is to provide a hot plate making it possible to heat an object to be heated uniformly, and the hot plate of the present invention is characterized in that a resistance element having a thickness dispersion of ±3 μm or less is formed on an insulating substrate.

1 . A hot plate wherein a resistance element having a thickness dispersion of ±3 μm or less is formed on an insulating substrate.  
     
     
         2 . The hot plate according to  claim 1 , wherein the thickness dispersion of the resistance element is ±1 μm or less.  
     
     
         3 . The hot plate according to  claim 1  or  2 , wherein the thickness of said resistance element is from 0.5 to 500 μm.  
     
     
         4 . The hot plate according to  claim 3 , wherein the thickness of said resistance element is from 1 to 10 μm.  
     
     
         5 . The hot plate according to any of  claims 1  to  4 , wherein said insulating substrate is at least one kind selected from a nitride ceramic, a carbide ceramic and a resin.  
     
     
         6 . The hot plate according to any of  claims 1  to  5 , wherein said resistance element is made of scaly noble metal powder.  
     
     
         7 . The hot plate according to any of  claims 1  to  6 , characterized in that said resistance element has a multilayer structure, and among a plurality of layers constituting said resistance element, the layer nearest to the substrate is made of titanium or chromium.  
     
     
         8 . The hot plate according to any of  claims 1  to  7 , characterized in that said resistance element is composed of a first layer made of titanium; a second layer made of molybdenum and having a larger thickness than said first layer, on said first layer; and a third layer made of nickel and having an intermediate thickness between the thickness of said first layer and that of said second layer, on said second layer.  
     
     
         9 . The hot plate according to any of  claims 1  to  8 , characterized in that said resistance element is composed of a titanium layer having a thickness of 0.1 to 0.5 μm, a molybdenum layer having a thickness of 0.5 to 7.0 μm, on said titanium layer, and a nickel layer having a thickness of 0.4 to 2.5 μm, on said molybdenum layer.  
     
     
         10 . A process for producing a hot plate wherein a resistance element having a thickness dispersion of ±3 μm or less is formed on an insulating substrate, 
 characterized by forming said resistance element by a film-depositing method based on a dry process.  
 
     
     
         11 . A process for producing a hot plate wherein a resistance element having a thickness dispersion of ±3 μm or less is formed on an insulating substrate, 
 characterized by forming said resistance element by RF sputtering.  
 
     
     
         12 . A process for producing a hot plate wherein a resistance element having a thickness dispersion of ±3 μm or less is formed on an insulating substrate, 
 characterized by printing a resistance element paste made of scaly noble metal powder and firing the paste.