1. Field of the Invention
This invention relates to semiconductor packages, and, more specifically, to a semiconductor package and a method of manufacturing having more reliable electrical conductive patterns.
2. Description of the Related Art
A conventional semiconductor package includes a substrate of an approximate planar plate having a plurality of conductive patterns at the top and bottom surfaces of a resin layer thereof. A semiconductor die is bonded to the die pad of the substrate by means of an adhesive. A plurality of conductive wires is used for electrically connecting the semiconductor die to the electrically conductive patterns of the substrate. An encapsulant is used for covering the semiconductor die and the conductive wires. A plurality of solder balls is fused to the electrically conductive patterns of the substrate.
The plurality of conductive patterns of the substrate consists of the top and bottom surfaces of the resin layer, respectively, in order to allow the conductive wires to be bonded and the solder balls to be fused. A photo imaging type protective layer of a predetermined thickness, which is made of an epoxy and an acrylate, is screen-printed and hardened on the surfaces of the resin layer as well as the electrically conductive patterns. The photo imaging type protective layer is used to protect the electrically conductive patterns from the external moisture, dust and mechanical impact or the like. Here, the photo imaging type protective layer is not formed in the wire bonding regions nor the solder balls fusing regions. The reason for use of the photo imaging type protective layer, as described above, is that it allows each electrically conductive pattern to be insulated. The photo imaging type protective layer is irradiated by a ray of a predetermined wavelength and heat, it is then rapidly cured from a liquid phase to a solid phase by the reaction of a photo reactant existing in the protective layer. This produces a superior and convenient operation of efficiency.
Meanwhile, in the semiconductor package which uses such a substrate, a demand on the physical reliance of the package has tended to gradually increase. That is, according to a tendency of the semiconductor package to be integrated and dense, more narrow and thin conductive patterns have been required, Accordingly, many-sided efforts have been advanced in order to solve the above reliance problem of the package.
In the case of the photo imaging type protective layer, which is widely used in the substrate at present as described above, there are advantages in that it has superior insulation and an easy formation procedure of patterns. However, since the electrically conductive patterns are thin and narrow, cracks or other damage to the electrically conductive patterns can occur, owing to a pressure generated from the encapsulating or singulating process of the semiconductor package. This causes the reliance of the package to be lowered. That is, the electrically conductive patterns contacted indirectly with a mold, during encapsulating process, can be cracked or damaged. Also, the electrically conductive patterns cut by a cutter, which is located at the edge of the substrate during the singulating process, can be cracked or damaged.
Since the photo imaging type protective layer is easily damaged by mechanical impact, there is a problem in that the electrically conductive patterns inside the protective layer can be easily contaminated or damaged. Here, because a property of the matter, an acrylate, which is one of the elements of the photo imaging type protective layer, is soft as well as brittle, the photo imaging type protective layer can be easily damaged, as described above. That is, the property of matter of an epoxy forming the protective layer can withstand an external force very well. However, the acrylate is easily broken by external forces.
A semiconductor package has a substrate comprising a resin layer of an approximate planar plate, a die pad coupled at a top surface of a center area of the resin layer and having a printed photo imaging type protective layer thereon and a plurality of electrically conductive patterns, on which the photo imaging type protective layer and a thermosetting protective layer are printed in a consecutive order, formed at a periphery of the die pad. A semiconductor die is coupled to the photo imaging type protective layer on the die pad of the substrate by an adhesive. A plurality of conductive wires is used for electrically connecting the semiconductor die to the electrically conductive patterns. An encapsulant is used for covering the semiconductor die, the conductive wires and the surface of thermosetting protective layer on the electrically conductive patterns in order to protect them from the external environment. A plurality of contacts are coupled to the electrically conductive patterns of the substrate.
The present invention is best understood by reference to the following detailed description when read in conjunction with the accompanying drawings.
USPTO Backgrounds
USPTO Backgrounds