Thin-film resistor, wiring substrate, and method for manufacturing the same

Abstract

A thin-film resistor that enables a pattern to be simply formed by means of wet etching, that has an excellent resistance temperature characteristic, and that can be easily manufactured, and a method for manufacturing this thin-film resistor, as well as a wiring substrate with this thin-film resistor formed therein. A thin resistor film according to this invention has a structure in which crystal grains deposit in the matrix of amorphous titanium nitride. The thin resistor film is formed on a substrate. The crystal grains includes at least one of crystal titanium nitride and crystal titanium. The thin resistor film can be manufactured using a simple process and can provide a wide range of resistance values with a small tolerance and a temperature coefficient of resistance close to zero.

What is claimed is:  
     
         1 . A thin-film resistor comprising a composite of at least either crystal titanium nitride or crystal titanium and amorphous titanium nitride.  
     
     
         2 . The thin-film resistor according to  claim 1 , wherein the number of nitrogen atoms in said composite is ⅓ to ⅔ of the total number of atoms.  
     
     
         3 . The thin-film resistor according to  claim 1 , wherein said crystal titanium nitride is at least one of TiN and Ti 2 N.  
     
     
         4 . The thin-film resistor according to  claim 2 , wherein said crystal titanium nitride is at least one of TiN and Ti 2 N.  
     
     
         5 . The thin-film resistor according to  claim 1 , wherein the specific resistivity is 0.1 mΩ·cm to 100 mΩ·cm.  
     
     
         6 . A method for manufacturing a thin-film resistor, wherein the thin-film resistor according to  claim 1  is manufactured using as a process gas a nitrogen gas or a gas containing a nitrogen and using a titanium target and DC magnetron sputtering.  
     
     
         7 . The method for manufacturing a thin-film resistor according to  claim 6 , wherein the partial pressure of said nitrogen gas is controlled during sputtering to vary the amount of nitrogen in said composite.  
     
     
         8 . A wiring substrate with the thin-film resistor according to  claim 1  built in its inner layer or on its surface.  
     
     
         9 . A wiring substrate having a wiring provided on an insulator wherein; said wiring is placed on said insulator via a thin titanium nitride film provided on said insulator.  
     
     
         10 . The wiring substrate according to  claim 9 , wherein; said wiring is configured by means of copper electroplating.  
     
     
         11 . A wiring substrate having a structure in which a wiring is connectively provided on an insulator via a resistor, wherein; said resistor comprises a thin titanium nitride film and wherein the thin titanium nitride film is interposed between said wiring and said insulator.  
     
     
         12 . The wiring substrate according to  claim 11 , wherein; said wiring is configured by means of copper electroplating.  
     
     
         13 . The wiring substrate according to claims  9 , wherein; the wiring connected via said thin titanium nitride film is placed on one of plural layers of insulators or over a plurality of insulators.  
     
     
         14 . A method for manufacturing a wiring substrate comprising the steps of: 
 forming a thin titanium nitride film on an insulator,    forming a wiring on said thin titanium nitride film, and    patterning said thin titanium nitride film.    
     
     
         15 . A method for manufacturing a wiring substrate comprising the steps of: 
 forming a thin titanium nitride film on an insulator,    forming on said thin titanium nitride film a wiring having a discontinuous portion, and    patterning into the resistor a portion of said thin titanium nitride film that is located under the discontinuous portion of said wiring.    
     
     
         16 . The method for manufacturing a wiring substrate according to  claim 14  comprising the steps of: 
 after forming said titanium nitride film, forming a thin copper film on said thin titanium nitride film formed, forming a copper wiring on the thin copper film, and removing said thin copper film.  
 
     
     
         17 . The method for manufacturing a wiring substrate according to  claim 16 , wherein; said thin titanium nitride film and thin copper film are formed by means of sputtering.  
     
     
         18 . The method for manufacturing a wiring substrate according to  claim 17 , wherein; the process for forming said copper wiring is an electroplating method.  
     
     
         19 . The method for manufacturing a wiring substrate according to any of claims  18  comprising the step of: 
 before forming said copper wiring, forming a resist film and patterning this resist film.  
 
     
     
         20 . The method for manufacturing a wiring substrate according to any of claims  19 , wherein; in patterning said thin titanium nitride film, the thin titanium nitride film is etched using a water solution containing ammonia and hydrogen peroxide.  
     
     
         21 . The method for manufacturing a wiring substrate according to any of claims  20 , wherein; said thin titanium nitride film is formed by means of sputtering and wherein the surface temperature is set at 150° C. or more during sputtering.