Substrate for suspension, and production process thereof

Abstract

The present invention provides a substrate for suspension that includes a first structural part including a metal supporting substrate, an insulating layer, a wiring layer, and a cover layer, and a second structural part formed so as to extend continuously from the first structural part and has no metal supporting substrate. A position of an edge of an upper surface of the insulating layer coincides with a position of an edge of the lower surface of the cover layer or the position of the edge of the upper surface of the insulating layer is positioned on a side closer to the wiring layer than to the position of the edge of the lower surface of the cover layer at a boundary region between the first structural part and the second structural part.

1 . A production process of substrate for suspension comprising:
 a metal supporting substrate,   an insulating layer formed on the metal supporting substrate,   a wiring layer formed on the insulating layer,   a cover layer formed to cover the wiring layer,   a first structural part including the metal supporting substrate, the insulating layer, the wiring layer, and the cover layer, and   a second structural part formed so as to extend continuously from the first structural part and has no metal supporting substrate,   the method comprises a step of:   forming at least one of the insulating layer and the cover layer such that at least one of a width from an edge of the wiring layer to an edge of the insulating layer and a width from the edge of the wiring layer to an edge of the cover layer is locally large in planar view at a boundary region between the first structural part and the second structural part.   
     
     
         2 . The production process of substrate for suspension according to  claim 1 , wherein the insulating layer and the cover layer are formed such that a position of the edge of the insulating layer coincides with a position of the edge of the cover layer at the boundary region. 
     
     
         3 . A production process of substrate for suspension comprising:
 a metal supporting substrate,   an insulating layer formed on the metal supporting substrate,   a wiring layer formed on the insulating layer,   a cover layer formed to cover the wiring layer,   a first structural part including the metal supporting substrate, the insulating layer, the wiring layer, and the cover layer, and   a second structural part formed so as to extend continuously from the first structural part and has no metal supporting substrate,   the method comprises a step of:   a wiring layer formation step of forming an auxiliary wiring layer between an edge of the wiring layer and an edge of the insulating layer in planar view at a boundary region between the first structural part and the second structural part.   
     
     
         4 . The production process of substrate for suspension according to  claim 3 , wherein the wiring layer and the auxiliary wiring layer are formed simultaneously in the wiring layer formation step. 
     
     
         5 . The production process of substrate for suspension according to  claim 1 , further comprises steps of:
 forming the metal supporting substrate having a tongue section for mounting a device and an outrigger section positioned outside the tongue section; and   forming the wiring layer between the tongue section and the outrigger section in planar view.   
     
     
         6 . The production process of substrate for suspension according to  claim 3 , further comprises steps of:
 forming the metal supporting substrate having a tongue section for mounting a device and an outrigger section positioned outside the tongue section; and   forming the wiring layer between the tongue section and the outrigger section in planar view.