1. Field of the Invention
The present invention relates to a method of cutting a ceramic green block.
2. Description of the Background Art
In order to cut out chips from a fired ceramic block or to cut an Si wafer, a dicing saw which has a high dimensional cutting accuracy is normally employed. However, such a dicing saw, which is adapted to cut a workpiece with a high-speed rotary knife, is generally not suitable for cutting a soft or adhesive material.
On the other hand, a ceramic green block can generally be punched or stamped cut by a press blade. Such a ceramic green block is soft enough to allow a press blade to punch out chips from the block at a higher cutting speed than that of the dicing saw, with equipment having a lower cost. Thus, the cutting operation can be carried out at a reasonable cost.
Chips cut out from a ceramic green block are employed as elements for obtaining ceramic electronic components, for example.
As electronic components have been increasingly miniaturized and improved in performance in recent years, chips must be cut out from a ceramic green block with higher cutting accuracy.
When a blade is employed for punching out such chips, it is difficult to attain high cutting accuracy, due to the movement of the block or the chips during cutting. Further, it is difficult to punch chips from a ceramic green block which has a hard internal portion of a metal film or a metal foil by such a blade.
In contrast, a dicing saw has satisfactory cutting accuracy. When such a dicing saw is adapted to cut a soft workpiece such as a ceramic green block, however, the cost for the cutting step is increased since such a soft material cannot be cut at a high speed.
Accordingly, an object of the present invention is to provide a method for efficiently cutting a ceramic green block by use of a dicing saw.
In order to solve the aforementioned technical problem, the present invention is characterized in that the ceramic green block is heat treated, thus improving the hardness of the block before the same is cut by a dicing saw.
In the ceramic green block to which the present invention is applied, at least a portion to be cut is not necessarily formed only by a ceramic green body, but may contain a different material in the form of a metal paste film or a metal foil, for example.
According to the present invention, the ceramic green sheet is heat treated to improve its hardness.
Therefore, the ceramic green block can be cut by a dicing saw at a high speed.
Since the ceramic green sheet is cut by a dicing saw, it is possible to improve cutting accuracy, as well as to obtain a smooth cut surface.
According to the present invention, therefore, chips for electronic components can be cut with high accuracy, whereby it is possible to miniaturize and improve the performance of such electronic component chips.
In the present invention, the ceramic green block preferably contains a binder in an amount 4 to 20 percent by weight of the block. If the content of the binder is less than 4 percent by weight, it is impossible to bind the block when a solvent is vaporized by heat treatment. When the content of the binder exceeds 20 percent by weight, on the other hand, the block is undesirably softened during the process of heat treatment.
In the present invention, further, a Vickers hardness of the ceramic green block is preferably brought into a range of 20 to 100 kg/cm2 by the heat treatment. Such a preferable range of Vickers hardness has been experimentally determined, in order to attain an excellent cutting property for cutting the ceramic green block with a dicing saw.
In the heat treatment step according to the present invention, the heat treatment temperature is preferably selected within a range of 50 to 200xc2x0 C. If the heat treatment temperature is less than 50xc2x0 C., no effect of heating appears on the ceramic green block, while the binder is undesirably converted if the heat treatment temperature exceeds 200xc2x0 C.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention.