1. Field of the invention
The invention relates to a semiconductor device and a method of manufacturing the same, specifically relates to a semiconductor device with a semiconductor chip encased in a hollow ceramic package and a method of manufacturing the same.
2. Description of the related art
A conventional method for encasing a semiconductor chip in a hollow ceramic package is disclosed in the reference [JP 2006-179740A]. According to JP 2006-179740A, a ceramic sheet, which is divided into a plurality of individual headers (containers) later, and a metal plate, which is divided into a plurality of individual lids for the headers later, are used for the ceramic package. The ceramic sheet includes a plurality of headers disposed in a matrix, and each header includes a cavity, which has an opening located at an upper surface of the ceramic sheet, for placing a semiconductor chip therein. The ceramic sheet also includes grooves formed at a back surface, which is opposite to the upper surface, for defining the headers. In order to manufacture a semiconductor device with a semiconductor chip encased in a hollow ceramic package, the semiconductor chip is placed in each cavity, and then is connected to the header by bonding wires. Then, the metal plate is placed on the ceramic sheet by sandwiching a sealing sheet. After that, the metal plate is fixed to the ceramic plate by using a roll electrode, which melts down the sealing sheet by electric power applied to the roll electrode. Then, after only the metal plate is diced, the ceramic sheet is divided into individual semiconductor devices in a so-called chocolate-break manner by an external force along the grooves formed therein.
However, according to the conventional method, since the surface of the metal plate on which the roller electrode is contacted is a flat surface, the contact area of the roller electrode and the metal plate is limited so that a high voltage is required to melt-down the sealing sheet for fixing the metal plate to the ceramic sheet. Further, it is not easy to divide the metal plate only by the dicing method. Moreover, two dividing steps are required in the conventional method. Namely, the first step is a dicing process for dicing the metal plate only, and the second step is a chocolate-breaking process for breaking a ceramic sheet in order to divide into the individual semiconductor devices. The complex process makes the manufacturing process complex, decreases the productivity, and increase the cost for production.