Method for manufacturing circuit devices
View Patent ↗Priorly, semiconductor devices wherein a flexible sheet with a conductive pattern was employed as a supporting substrate, a semiconductor element was mounted thereon, and the ensemble was molded have been developed. In this case, problems occur that a multilayer wiring structure cannot be formed and warping of the insulating resin sheet in the manufacturing process is prominent. In order to solve these problems, a laminated plate 10 formed by laminating a first conductive film 11 and a second conductive film 12 is covered with a photoresist layer PR having opening portions 13 with inclined surfaces 13 S, a conductive wiring layer 14 is formed in the opening portions by electrolytic plating to form inverted inclined surfaces 14 R, and then, when covering the same with the sealing resin layer 21 , an anchoring effect is produced by making the sealing resin layer 21 bite into the inverted inclined surfaces 14 R so as to strengthen bonding of the sealing resin layer 21 with the conductive wiring layer 14.
1. A method of manufacturing circuit devices, comprising:
preparing a substrate by laminating a first conductive film and a second conductive film to cover a principle surface of the first conductive film;
covering said second conductive film with a photoresist layer in a desirable pattern and having an inclined surface at opening portions;
selectively forming a conductive wiring layer at the opening portions of said photoresist layer and providing an inverted inclined surface around said conductive wiring layer;
removing said second conductive film by use of said conductive wiring layer as a mask;
fixedly fitting semiconductor elements on said first conductive film and electrically connecting electrodes of said semiconductor elements with predetermined parts of said conductive wiring layer;
covering said semiconductor elements with a sealing resin layer and making said sealing resin layer produce an anchoring effect at said inverted inclined surface of said conductive wiring layer; and
removing said first conductive film to expose said second conductive film positioned on the rear surface of said sealing resin layer and said conductive wiring layer.
2. The method of claim 1 , wherein said second conductive film is formed by silver electroplating.
3. The method of claim 1 , wherein said photoresist layer is heat-treated after development so as to form an inclined surface at said opening portions.
4. The method of claim 1 , wherein as said photoresist layer, a positive photoresist layer is used, and an inclined surface is formed by use of inferior resolution during development.
5. The method of claim 1 , wherein said conductive wiring layer is formed at said opening portion by copper electroplating while using said first conductive film as an electrode.
6. The method of claim 1 , wherein an etching solution for said second conductive film is an iodine-based solution.
7. The method of claim 1 , wherein said second conductive film and said sealing resin layer remaining when said first conductive film is etched are used as an etching stopper.
8. The method of claim 6 , wherein a solution containing ferric chloride or cupric chloride is used as a solution to perform said etching.
9. The method of claim 1 , wherein external electrodes are formed by adhering a brazing filler material to the remaining second conductive film.