Wet etchable laminated body, insulation film, and electronic circuit part using the laminated body and the film

Abstract

The present invention provides a laminate comprising an insulating layer having suppressed dusting properties, an insulating film comprising the insulating layer, and an electronic circuit component comprising a pattern of the insulating layer. The laminate has a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer. The insulating layer comprises a laminate of two or more wet etchable insulating unit layers. At the interface between the inorganic material layer and the insulating layer, surface irregularities of the inorganic material layer have been transferred onto the surface of the insulating layer. The average height of the surface irregularities transferred onto the insulating layer is less than the thickness of the outermost insulating unit layer in the insulating layer.

1 . A laminate having a layer construction of first inorganic material layer-insulating layer-second inorganic material layer or a layer construction of inorganic material layer-insulating layer, 
 said insulating layer comprising a laminate of two or more wet etchable insulating unit layers,    at the interface between at least one of the inorganic material layers and the insulating layer, surface irregularities of the inorganic material layer having been transferred onto the surface of the insulating layer,    the average height of the surface irregularities transferred onto the insulating layer being less than the thickness of the outermost insulating unit layer in the insulating layer.    
     
     
         2 . The laminate according to  claim 1 , wherein, when the average height of profile irregularities is expressed in terms of mean roughness Rz specified in JIS (Japanese Industrial Standards) C 6515, the thickness of the insulating unit layer is 1.1 to 3 times Rz.  
     
     
         3 . The laminate according to  claim 2 , wherein the mean roughness Rz of the surface of the inorganic material layer is 0.2 to 15 μm.  
     
     
         4 . The laminate according to  claim 1 , wherein the insulating layer has a layer construction of adhesive insulating layer-core insulating layer-adhesive insulating layer.  
     
     
         5 . The laminate according to  claim 1 , wherein all the insulating unit layers constituting the insulating layer contain an organic material.  
     
     
         6 . The laminate according to  claim 1 , wherein at least one of the insulating unit layers constituting the insulating layer is formed of an organic material with an inorganic material incorporated therein.  
     
     
         7 . The laminate according to  claim 1 , wherein at least one of the insulating unit layers constituting the insulating layer has a coefficient of linear thermal expansion of not more than 30 ppm.  
     
     
         8 . The laminate according to  claim 1 , wherein the difference in coefficient of linear thermal expansion between at least one of the insulating unit layers constituting the insulating layer and the inorganic material layer is not more than 15 ppm.  
     
     
         9 . The laminate according to  claim 1 , wherein at least one of the insulating unit layers constituting the insulating layer is formed of a polyimide resin.  
     
     
         10 . The laminate according to  claim 4 , wherein, in the insulating layer having a layer construction of adhesive insulating layer-core insulating layer-adhesive insulating layer, the two adhesive insulating layers, which sandwich the core insulating layer therebetween, are each formed of a polyimide resin, and the polyimide resin constituting one of the adhesive insulating layers is identical to the polyimide resin constituting the other adhesive insulating layer in composition.  
     
     
         11 . The laminate according to  claim 4 , wherein, in the insulating layer having a layer construction of adhesive insulating layer-core insulating layer-adhesive insulating layer, the two adhesive insulating layers, which sandwich the core insulating layer therebetween, are each formed of a polyimide resin, and the polyimide resin constituting one of the adhesive insulating layers is different from the polyimide resin constituting the other adhesive insulating layer in composition.  
     
     
         12 . The laminate according to  claim 1 , wherein the insulating layer is etchable with an alkaline etching liquid having a pH value of 7 or greater.  
     
     
         13 . The laminate according to  claim 1 , wherein the inorganic material constituting the inorganic material layer is selected from copper, alloy copper, stainless steel, surface treated copper, surface treated alloy copper, and surface treated stainless steel.  
     
     
         14 . The laminate according to  claim 1 , wherein both the first inorganic material layer and the second inorganic material layer are formed of copper or surface treated copper.  
     
     
         15 . The laminate according to  claim 1 , wherein both the first inorganic material layer and the second inorganic material layer are formed of alloy copper or surface treated alloy copper.  
     
     
         16 . The laminate according to  claim 1 , wherein both the first inorganic material layer and the second inorganic material layer are formed of stainless steel or surface treated stainless steel.  
     
     
         17 . The laminate according to  claim 1 , wherein any one of the first inorganic material layer and the second inorganic material layer is formed of stainless steel or surface treated stainless steel and the other inorganic material layer is formed of copper or surface treated copper.  
     
     
         18 . The laminate according to  claim 1 , wherein any one of the first inorganic material layer and the second inorganic material layer is formed of stainless steel or surface treated stainless steel and the other inorganic material layer is formed of alloy copper or surface treated alloy copper.  
     
     
         19 . An electronic circuit component produced by wet etching the insulating layer in the laminate according to any one of  claims 1  to  18 .  
     
     
         20 . A suspension for a hard disk drive, produced by wet etching the insulating layer in the laminate according to any one of  claims 1  to  18 .  
     
     
         21 . An insulating film comprising a laminate of two or more wet etchable insulating unit layers, 
 said insulating film being adaptable for stacking on an inorganic material layer,    said inorganic material layer having surface irregularities of which the average height is less than the thickness of the outermost insulating unit layer in the insulating layer.    
     
     
         22 . The insulating film according to  claim 21 , wherein at least one of the insulating unit layers constituting the insulating film is formed of a polyimide resin.  
     
     
         23 . The insulating film according to  claim 21 , wherein all the insulating unit layers constituting the insulating film are formed of a polyimide resin.  
     
     
         24 . The insulating film according to  claim 22 , wherein the insulating film has a layer construction of adhesive polyimide layer-core polyimide layer-adhesive polyimide layer.  
     
     
         25 . The insulating film according to  claim 21 , wherein at least one of the insulating unit layers constituting the insulating film is formed of a low-expansion polyimide having a coefficient of linear thermal expansion of not more than 30 ppm.  
     
     
         26 . The insulating film according to  claim 21 , wherein the insulating film is etchable with an alkaline etching liquid having a pH value of 7 or greater.