High-dielectric sheet, a printed circuit board having the high-dielectric sheet and production methods thereof

Abstract

A method of producing a capacitor for a printed circuit board includes producing high-dielectric sheets and selecting ones of the high-dielectric sheets, which are substantially free from a defect after the heat process. Each of the high-dielectric sheets is produced by providing a first electrode, forming a first sputter film on the first electrode, forming an intermediate layer on the first sputter film by calcining a sol-gel film, forming a second sputter film on the intermediate layer, and providing a second electrode on the second sputter film. The high-dielectric sheets are subjected to a heat process in which the high-dielectric sheets are subjected to a first temperature at least once and a second temperature higher than the first temperature at least once.

1 . A method of producing a capacitor for a printed circuit board, comprising:
 producing a plurality of high-dielectric sheets, each of the plurality of high-dielectric sheets being produced by providing a first electrode, forming a first sputter film on the first electrode, forming an intermediate layer on the first sputter film by calcining a sol-gel film, forming a second sputter film on the intermediate layer, and providing a second electrode on the second sputter film; and   subjecting the plurality of high-dielectric sheets to a heat process in which the high-dielectric sheets are subjected to a first temperature at least once and a second temperature higher than the first temperature at least once; and   selecting ones of the plurality of high-dielectric sheets, which are substantially free from a defect after the heat process.   
     
     
         2 . The method according to  claim 1 , wherein the first temperature is 0° C. or lower. 
     
     
         3 . The method according to  claim 1 , wherein the second temperature is 100° C. or higher. 
     
     
         4 . A high-dielectric sheet for a printed circuit board, comprising:
 a first electrode;   a first sputter film formed on the first electrode;   an intermediate layer formed on the first sputter film by calcining a sol-gel film;   a second sputter film formed on the intermediate layer; and   a second electrode provided on the second sputter film.   
     
     
         5 . The sheet according to  claim 4 , wherein the first sputter film, the intermediate layer and the second sputter film have a total thickness in the range between 0.4 and 3 μm. 
     
     
         6 . The sheet according to  claim 4 , wherein the first sputter film has a thickness of 0.1 μm or greater. 
     
     
         7 . The sheet according to  claim 4 , wherein the second sputter film has a thickness of 0.1 μm or greater. 
     
     
         8 . The sheet according to  claim 4 , wherein the intermediate layer is thicker than the first and second sputter films. 
     
     
         9 . The sheet according to  claim 4 , wherein the second sputter film is thinner than the first sputter film. 
     
     
         10 . The sheet according to  claim 4 , wherein the first sputter film, the intermediate layer and the second sputter film comprise at least one material selected from the group consisting of barium titanate, SrTiO 3 , TaO 3 , Ta 2 O 5 , lead zirconate titanate, lead lanthanum zirconate titanate, lead niobium zirconate titanate, lead calcium zirconate titanate and lead strontium zirconate titanate. 
     
     
         11 . The sheet according to  claim 4 , wherein the first electrode comprises a material selected from the group consisting of nickel, copper, platinum, gold and silver. 
     
     
         12 . The sheet according to  claim 4 , wherein the second electrode comprises a material selected from the group consisting of copper, nickel and tin. 
     
     
         13 . A printed circuit board comprising:
 a core substrate; and   a capacitor positioned over the core substrate, the capacitor having a first electrode, a first sputter film formed on the first electrode, an intermediate layer formed on the first sputter film by calcining a sol-gel film, a second sputter film formed on the intermediate layer, and a second electrode provided on the second sputter film.