Method for forming an integrated circuit package with via interconnection

Abstract

An integrated circuit package, and a method for forming the integrated circuit package, including a single layer or multilayer substrate in which interconnection vias are formed is described. Laser energy is swept across a surface of a mask in which holes have been formed. Laser energy passing through the holes of the mask forms vias in a substrate held in place below the mask. The laser energy is swept at such a speed and is maintained at such an energy level that the laser energy forms vias in the substrate, but does not penetrate a set of leads attached to the substrate. Vias may be formed in this way by either a mask imaging, contact mask or conformal mask technique. The laser energy is emitted from a non-thermal (e.g., excimer) laser. The substrate is formed of an organic (e.g., epoxy) resin. The resin may include reinforcing fibers (e.g., aramid fibers). Substrates may be formed on one or both sides of the set of leads. After formation in the substrate, the vias are coated with an electrically conductive material. The method of via formation is fast, inexpensive, achieves higher via density, and avoids overheating of the substrate.