Patent Publication Number: US-6216682-B1

Title: Cutting apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cutting apparatus for cutting a workpiece such as a semiconductor wafer. 
     2. Background Art 
     As a conventional apparatus for cutting workpieces such as a semiconductor wafer, a cutting apparatus as shown in FIG. 6 is known. In this cutting apparatus, a cassette  1  is mounted on a cassette mounting section A which moves up and down. In the cassette  1  are stored semiconductor wafers  2  as the workpieces. A semiconductor wafer  2 , which is fixed on a frame  4  via a tape  3 , is carried out therefrom to a standby section B by carrying means  5 . Then, the carried semiconductor wafer  2  is conveyed to a chuck table  7  by a swing arm  6 . The semiconductor wafer  2  held on the chuck table  7  is positioned by alignment means  8 , and then cut by cutting means  9 . 
     In the cutting by the aforesaid cutting means  9 , the semiconductor wafer  2  is cut by a blade  10  rotating at a high speed while being supplied with cutting water. Here, due to wear of cutting edge thereof and suchlike, the blade  10  may sometimes generate variations in depth of cut. The occurrence of such variations lowers the cutting accuracy as well as adversely affects the subsequent processing steps. 
     On this account, setup for adjusting the blade  10  to its correct position is conducted in the cutting process. However, some of the cutting water supplied in cutting is clinging to the cutting edge of the blade  10 , giving rise to a problem in that the setup cannot be carried out surely and precisely. 
     SUMMARY OF THE INVENTION 
     In order to solve such conventional problem, an object of the present invention is to provide a cutting apparatus in which the setup of the blade can be carried out surely and precisely. 
     The foregoing object and other objects of the present invention have been achieved by the provision of a cutting apparatus comprising at least a chuck table for holding a workpiece and cutting means for cutting the workpiece held by the chuck table, wherein: the aforesaid cutting means comprises a spindle unit, a blade to be attached to a rotating spindle of the spindle unit, and a cutting-water supplying nozzle for supplying cutting water to the blade and the workpiece; and the aforesaid cutting means is further provided with an air-blowing nozzle adjacent to the aforesaid blade, the air-blowing nozzle for supplying air to the peripheral portion of the blade. 
     In the cutting apparatus, the aforesaid cutting-water supplying nozzle and said air-blowing nozzle may be provided on a blade cover for covering the blade. 
     Moreover, air-blowing piping for feeding air to the aforesaid air-blowing nozzle may be arranged within the spindle unit. 
     According to the present invention described above, since the air-blowing nozzle is arranged adjacent to the blade, air can be blown from the air-blowing nozzle to the blade, in advance of the setup or in carrying out the setup, to surely remove the cutting water clinging to the blade. This brings about an effect that both contact and non-contact type setup can be carried out surely and precisely. 
     Besides, in the contact type setup, not only the cutting water on the blade but that on the chuck table can be eliminated as well. In the non-contact type, the cutting water and contaminants clinging to its light emitting element and light receiving element can be removed. Accordingly, it is possible to improve the setups in accuracy. 
     Furthermore, arranging the piping of the air-blowing nozzle within the spindle unit can eliminate the obstacle to the indexing move of the spindle unit as well as avoid the contamination to the surface of workpieces due to the dropping water after the cutting. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This and other objects and advantages of the present invention will become clear from the following description with reference to the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a cutting apparatus according to the present invention; 
     FIG. 2 is a perspective view of the main portions of the same; 
     FIG. 3 is an explanatory diagram showing the operation of an air-blowing nozzle; 
     FIGS.  4 (A) and  4 (B) are diagrams illustrating the setup of a blade; among which, FIG.  4 (A) is an explanatory diagram for contact type setup, and FIG.  4 (B) an explanatory diagram for non-contact type setup; 
     FIG. 5 is a perspective view showing the main portions of another embodiment of the present invention; and 
     FIG. 6 is a perspective view of a conventional cutting apparatus. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. For purposes of description, like members as those in the cutting apparatus described as of the conventional art are designated by like reference numerals or characters. 
     FIG. 1 shows a whole cutting apparatus according to the present invention. FIG. 2 shows the main portions of cutting means  9  provided in the cutting apparatus. The cutting means  9  comprises a spindle unit  11 , a blade  10  to be attached to a rotating spindle of this spindle unit  11 , and a blade cover  12  for covering the blade  10 . 
     The blade cover  12  has a pair of guide pipes  13  piercing through its side portion vertically. A pair of cutting-water supplying nozzles  14  are provided on the lower ends of the guide pipes  13  so as to horizontally face each other beyond the blade  10 . The upper ends of the guide pipes  13  are projected from the upper surface of the blade cover  12 , and on the respective upper ends are connected cutting-water supplying tubes  15 . Cutting water forced through the cutting-water supplying tubes  15  is fed through the guide pipes  13  into the cutting-water supplying nozzles  14 . From the cutting-water supplying nozzles  14 , the cutting water is sprayed onto the peripheral portion (cutting edge) of the blade  10 . 
     On the other side portion of the blade cover  12  is arranged an air-blowing nozzle  16 . As shown in FIG. 3, the lower end of the nozzle  16  is formed to bend toward the peripheral portion of the aforesaid blade  10 . To the upper end of the nozzle  16  is connected air-blowing piping  17 . Thereby, air forced through the air-blowing piping  17  is fed into the air-blowing nozzle  16 , and is blown through the lower end thereof against the peripheral portion of the blade  10 . 
     FIGS.  4 (A) and  4 (B) illustrate the setup of the blade  10 , which is to be conducted prior to and in process of the cutting of a workpiece (semiconductor wafer  2 ). More specifically, FIG.  4 (A) illustrates contact type setup, i.e., a method of using electric means, in which the rotating blade  10  is put into contact with an end of the upper surface of a chuck table  7 , and the current flowing the closed electric circuit is detected to confirm the edge position of the blade  10 . FIG.  4 (B) illustrates non-contact type setup, i.e., a method of using optical means, in which the rotating blade  10  is put between a light emitting element P and a light receiving element Q, and interception of the light beam therebetween is detected to confirm the edge position of the blade  10 . 
     In both the methods, blowing air from the aforesaid air-blowing nozzle  16  in advance of the setup or in the process of the setup can surely eliminate the cutting water clinging to the blade  10 , which makes it possible to carry out the setups surely and precisely. 
     Particularly, in the contact type setup, not only the cutting water on the blade  10  but that clinging to the contacting areas of the chuck table  7  can be removed as well. Meanwhile, in the non-contact type setup, it is possible to eliminate the cutting water and contaminants (cut chips) clinging to the light-emitting surface of the aforesaid light emitting element P and the light-receiving surface of the aforesaid light receiving element Q. As a result, the setups are improved in accuracy. 
     FIG. 5 shows another embodiment of the present invention, which basically has the same constitution as that described above, but is different in that the piping for the air-blowing nozzle is arranged within the spindle unit  11 . More specifically, the air-blowing piping  17  is arranged in the inside of the spindle unit  11 . The extremity thereof is connected to a path (not shown) formed inside the blade cover  12 , and the outlet of the path is in turn connected to the upper end of the aforesaid air-blowing nozzle  16 . Consequently, compressed air supplied through the air-blowing piping  17  is let through the path into the air-blowing nozzle  16 , and is blown through the lower end thereof against the peripheral portion of the blade  10 . 
     Here, the air-blowing piping  17  is not exposed to the outside; this solves a problem in that the piping tube gets caught on an adjacent member on the occasions of the indexing move of the spindle unit  11  during the cutting to obstruct the indexing move. It also eliminates a problem in that some contaminant water clinging to an exposed piping tube drops on the surface of the cut-completed semiconductor wafer  2  to contaminate the wafer. In this connection, the aforesaid cutting-water supplying tubes  15  are also preferably arranged within the spindle unit  11 . 
     On the completion of the cutting, conveying means  18  shown in FIG. 1 conveys the semiconductor wafer  2  to washing means  19 , in which the wafer is washed and dried. Then, the wafer is conveyed to the standby section B by the aforesaid swing arm  6 , and then stored into the cassette  1  by the carrying means  5 . 
     While the presently preferred embodiments of the present invention have been shown and described, it will be understood that the present invention is not limited thereto, and that various changes and modifications may be made by those skilled in the art without departing from the scope of the invention as set forth in the appended claims.