Use of Novel Adhesive-lined CCL Material in Single-pressed Multi-layer Circuit Boards with Inner Via-Holes in all Layers

摘要

This newly developed material and process enable the manufacturing, using a single pressing process, of multi-layer circuit boards with inner via-holes in every layer. Because this material utilizes conventional circuit board materials for its structural components, it not only provides proven high reliability and ease of circuit assembly, but also offers a short lead-time and high production yield due to adoption of the following processes used during the manufacture of conventional printed circuit boards.rn1. Use of a mu lti-layer substrate consisting of copper foil, glass-cloth-based insulation layer, adhesive layer, and cover filmrn2. Application of an etching process to the copper foil to produce a fine-patterned circuitrn3. Generation of blind via -holes using laser processing and hole cleaningrn4. Formation of via-bumps by filling metal-based paste and removing the cover filmrn5. A multi-layer circuit board with inner via-holes in all layers can be produced by aligning the insulation layers and pressing them together in a single operation.rnThe materials used in this process require a variety of key technologies that enable laser processing, dimensional control, conductive paste filling etc. This paper describes these techniques and includes an example of the production of a multi-layer circuit board in a single pressing operation, followed by reliability evaluation results for the whole circuit board.