Flip chip package

An improved flip chip package, comprising:

• a substrate member having top and bottom surfaces, a conductive pattern at least on one of the surfaces;
• the substrate made of a material including a first resin;
• a solder mask made of a material including a second resin having a thermal expansion coefficient substantially identical to that of the first resin of the substrate;
• the solder mask disposed on the top surface of the substrate such that a smooth outer surface is formed, the outer surface having a plurality of opening, each opening exposing a respective area of the conductive pattern of the substrate;
• an IC chip having an active side, an inactive side and a plurality of electrical contact pads on the active side;
• a plurality of solder bumps, each bump formed on a respective one of the plurality of contact pads on the IC chip;
• the active side of the IC chip directly attached to the outer surface of the solder mask such that after a soldering process each said bump has a remainder completely received in a respective one of the opening of the solder mask and connected to the conductive patterns therein;
• and
• a molding material encapsulating the chip and the top surface of the substrate.