1. Field of the Invention
The present invention relates to a method for manufacturing a semiconductor device having a protective cap for covering a functional element.
2. Related Arts
Conventionally, a semiconductor acceleration sensor has a movable portion on its silicon chip, whereby a physical quantity such as an acceleration is converted to an electric signal by displacement of the movable portion, which electric signal is then taken out. Also, in such a semiconductor device, it is performed to cover the movable portion by a cap in order to protect this movable portion.
As a method for manufacturing a semiconductor device wherein the movable portion is covered by the cap as mentioned above, there is that disclosed in Published Unexamined Japanese Patent Application No. H-5-326702. In this method, a plurality of sensors are formed on a silicon substrate and thereafter caps for protecting the sensors are bonded on the silicon substrate. Then, the silicon substrate and cap are cut while being simultaneously exposed to a water flow. And finally, lead wires are connected to the outside via the through openings for electrode leads formed beforehand in the silicon substrate.
However, in the method for manufacturing a semiconductor device disclosed in Published Unexamined Japanese Patent Application No. H-5-326702, pads connected to the sensor are disposed within the cap. Therefore, in order to make wire connection with the pads, it is necessary to form the through openings in the silicon substrate or cap as mentioned above. As a result, the process steps for the formation of the through openings does not only increase but does the water flow during the cutting step also inconveniently enter into the caps, raising the problem that the productivity decreases.