Processing apparatus including a water collection pan

A processing apparatus includes a chuck table for holding a workpiece, a processing unit for processing the workpiece held on the chuck table as supplying a processing water to the workpiece, and a water pan fixed to a bottom of the processing apparatus for receiving the processing water as a water leaked.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a processing apparatus including a water pan for receiving a water leaked at a bottom of the processing apparatus.

Description of the Related Art

A plurality of devices such as integrated circuits (ICs) and large scale integrations (LSIs) are formed on a front side of a wafer so as to be separated from each other by a plurality of crossing division lines. A back side of the wafer thus having the plural devices on the front side is ground by a grinding apparatus to reduce a thickness of the wafer to a predetermined thickness. Thereafter, the wafer is divided into individual device chips respectively corresponding to the plural devices, by using a dicing apparatus. The device chips thus obtained are used in electrical equipment such as mobile phones and personal computers.

A processing apparatus including such a grinding apparatus and a dicing apparatus uses a processing water such as a grinding water and a cutting water in a processing operation. Accordingly, there is a possibility that the processing water may leak. To cope with this problem, there is a case that a water pan is provided directly below the processing apparatus, so as to receive the processing water leaked and prevent the leaked water from spreading to a peripheral area outside the processing apparatus (see Japanese Patent Laid-Open No. 2016-221620, for example).

SUMMARY OF THE INVENTION

In the case of setting the water pan below the processing apparatus, the water pan and the processing apparatus are separately prepared. The water pan is first set on a floor, and the processing apparatus is next mounted on the water pan. Accordingly, in the case that the processing apparatus is directly set on the floor without setting the water pan, it is necessary to once lift the processing apparatus from the floor, next insert the water pan into a space defined between the floor and the processing apparatus, and finally mount the processing apparatus on the water pan, thus causing a troublesome or extensive operation. Also, in the case that the water pan is previously set below the processing apparatus, there is another problem such that the processing apparatus and the water pan must be separately moved in changing the position of the processing apparatus, so that much effort is required for position adjustment between the processing apparatus and the water pan.

It is therefore an object of the present invention to provide a processing apparatus which can eliminate the necessity of separately setting a water pan in setting the processing apparatus requiring the water pan.

In accordance with an aspect of the present invention, there is provided a processing apparatus including a chuck table for holding a workpiece; processing means for processing the workpiece held on the chuck table as supplying a processing water to the workpiece; and a water pan fixed to a bottom of the processing apparatus for receiving the processing water as a water leaked.

Preferably, the processing apparatus further includes a plurality of legs provided at the bottom of the processing apparatus; the water pan being fixed through the legs to the bottom of the processing apparatus. Preferably, the processing apparatus further includes a water leakage sensor for detecting the leakage of the processing water. The water pan has a bottom wall inclined with respect to a horizontal plane, and the water leaked to the water pan is collected at a predetermined low position set on the bottom wall of the water pan. The water leakage sensor is provided at the predetermined low position to detect the processing water collected at the predetermined low position. More preferably, the processing apparatus further includes water discharging means for discharging the processing water leaked to the water pan, the water discharging means being provided on the water pan at a position corresponding to the predetermined low position.

The term “processing water” in the present invention includes any water for use in the processing apparatus. For example, the processing water includes a cutting water for use in a cutting apparatus, a grinding water for use in a grinding apparatus, and a cleaning water for cleaning a workpiece.

According to the processing apparatus of the present invention, it is unnecessary to perform any extensive operation such that the processing apparatus is lifted by using a crane or the like, so as to set the water pan, and the water pan is next inserted into a space below the processing apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A preferred embodiment of the present invention will now be described in detail with reference to the attached drawings.FIG.1is a perspective view of a cutting apparatus (dicing saw)10according to the preferred embodiment. The cutting apparatus10includes a housing2having a rectangular bottom, a cassette12placed at a predetermined position on the housing2and adapted to be vertically moved, handling means14for drawing a semiconductor wafer W as a workpiece from the cassette12before processing and storing the semiconductor wafer W into the cassette12after processing, a chuck table20for holding the semiconductor wafer W, first transfer means16for transferring the semiconductor wafer W drawn from the cassette12to the chuck table20, cutting means22for cutting the semiconductor wafer W held on the chuck table20, the cutting means22having a cutting blade24and cutting water supplying means26, cleaning means28for cleaning the semiconductor wafer W cut by the cutting means22, second transfer means18for transferring the semiconductor wafer W from the chuck table20to a cleaning area where the semiconductor wafer W is to be cleaned by the cleaning means28, a water pan4fixed to a bottom of the cutting apparatus10, that is, a bottom of the housing2, for receiving a water leaked, and a plurality of legs6provided at the four corners of the bottom of the housing2and threadedly engaged with the housing2to fix the water pan4to the housing2.

The semiconductor wafer W to be cut by the cutting apparatus10is supported through a protective tape T to a ring frame F. A plurality of semiconductor wafers W each supported through the protective tape T to the ring frame F are previously stored in the cassette12so as to be arranged at given intervals in a vertical direction. The plural semiconductor wafers W are drawn one by one from the cassette12by operating the handling means14. Thereafter, each semiconductor wafer W is held under suction by the first transfer means16and transferred to the chuck table20by horizontally swinging the first transfer means16about a vertical axis. Thereafter, the semiconductor wafer W is held under suction on the chuck table20.

After holding the semiconductor wafer W on the chuck table20under suction, the chuck table20is moved toward the position below the cutting means22by operating moving means (not illustrated). During the movement of the chuck table20, alignment between the semiconductor wafer W and the cutting blade24is performed by alignment means (not illustrated). Thereafter, the semiconductor wafer W is cut by the cutting blade24as the chuck table20is moved. This cutting step is performed in such a manner that the semiconductor wafer W is cut along all of the division lines formed on the semiconductor wafer W to thereby divide the semiconductor wafer W into individual device chips. That is, the cutting operation of cutting the semiconductor wafer W along each division line is repeated as changing the relative position between the chuck table20and the cutting blade24and changing the direction of extension of the division lines. At this time, a cutting water is supplied from the cutting water supplying means26to the cutting blade24and a cutting position on the semiconductor wafer W.

After finishing the cutting step to divide the semiconductor wafer W into the individual device chips, the chuck table20is moved to the original position and the second transfer means18is next operated to transfer the semiconductor wafer W from the chuck table20to the cleaning means28. The semiconductor wafer W is cleaned by the cleaning means28in the following manner. The semiconductor wafer W is placed on a holding table (not illustrated) included in the cleaning means28and then held on the holding table under suction. Thereafter, the holding table is rotated and a cleaning water is supplied from cleaning water supplying means (not illustrated) to the semiconductor wafer W from an upper side thereof, thereby cleaning cutting dust off the semiconductor wafer W. Thereafter, the semiconductor wafer W is dried by performing a suitable step. Thereafter, the semiconductor wafer W is transferred by the first transfer means16and then stored into the cassette12by the handling means14. Thus, the cutting operation for one of the plural semiconductor wafers W stored in the cassette12is ended.

There are provided in the housing2covering a lower portion of the cutting apparatus10drive sources (not illustrated) for driving the handling means14and the first transfer means16, moving means (not illustrated) for moving the chuck table20, and elevating means (not illustrated) for vertically moving the cassette12. Further, there are also provided in the housing2a cutting water supplying circuit (not illustrated) for supplying the cutting water to a cutting area where the semiconductor wafer W is to be cut by the cutting blade24and discharging the cutting water used for cutting of the semiconductor wafer W to the outside of the cutting apparatus10and a cleaning water supplying circuit (not illustrated) for supplying the cleaning water to the cleaning means28and discharging the cleaning water used for cleaning of the semiconductor wafer W to the outside of the cutting apparatus10. The cutting water supplying circuit includes a water passage and pipe for supplying and discharging the cutting water. Similarly, the cleaning water supplying circuit includes a water passage and pipe for supplying and discharging the cleaning water. In a normal operating condition, there is no possibility that the cutting water and the cleaning water may leak from the cutting water supplying circuit and the cleaning water supplying circuit. However, when a hole or crack, for example, is formed at any position in the cutting water supplying circuit or the cleaning water supplying circuit, the cutting water or the cleaning water may leak to the outside of the cutting apparatus10. Further, the cutting water supplying circuit or the cleaning water supplying circuit may be clogged with any foreign matter to cause overflow from an unintentional position. In these cases, the cutting water or the cleaning water leaks from the cutting water supplying circuit or the cleaning water supplying circuit and then flows down through any path in the housing2to reach the bottom of the housing2.

According to the preferred embodiment, the water pan4for receiving the water leaked is fixed to the bottom of the cutting apparatus10. More specifically, the water pan4is fixed to the bottom of the housing2of the cutting apparatus10at the four corners of the bottom of the housing2where four legs6are provided. That is, the water pan4is fixed through the four legs6to the four corners of the bottom of the housing2. Accordingly, the cutting water and the cleaning water leaked in the housing2can be received by the water pan4.

The structure of the water pan4will now be described with reference toFIG.2. As illustrated inFIG.2, the water pan4is fixed to the bottom of the housing2constituting a lower portion of the cutting apparatus10. The water pan4includes a front wall41, a side wall42connected to the front wall41, another side wall43connected to the front wall41, a rear wall44connected to both the side wall42and the side wall43and opposed to the front wall41, and a bottom wall45provided so as to close a rectangular area surrounded by the front wall41, the side wall42, the side wall43, and the rear wall44. That is, the bottom wall45is connected to all of the front wall41, the side wall42, the side wall43, and the rear wall44in such a manner that these walls41to44rise from the peripheral edge of the bottom wall45.

In the condition where the water pan4is fixed to the bottom of the cutting apparatus10, the bottom wall45is inclined downward with respect to a horizontal plane as illustrated by a plurality of arrows S inFIG.2. Accordingly, the water leaked to the water pan4flows along the arrow S to be collected at a predetermined low position on the bottom wall45. A detecting portion72of a water leakage sensor70is provided at this predetermined low position. As illustrated inFIG.2, the bottom wall45is inclined with respect to a horizontal plane, so that a depth “b” of the corner formed by the rear wall44and the side wall43is larger than a depth “a” of the corner formed by the front wall41and the side wall42and the depth “a” of the corner formed by the front wall41and the side wall43. Further, a depth “c” of the corner formed by the rear wall44and the side wall42is larger than the depth “b.” In addition, the predetermined low position where the water leakage sensor70is provided is set near the corner formed by the rear wall44and the side wall42so as to be opposed to the rear wall44. The configuration of the water leakage sensor70is not specially limited. For example, the water leakage sensor70may be configured in such a manner that the detecting portion72has two electrodes and a processing water (cutting water or cleaning water) is adapted to come into contact with the two electrodes, whereby when the processing water comes into contact with the two electrodes, a current passes through the processing water to thereby detect that the processing water has leaked to the water pan4. With this configuration, even when water leakage has occurred at any position on the bottom of the cutting apparatus10, the processing water leaked can be collected at the predetermined low position where the detecting portion72of the water leakage sensor70is provided, so that the water leakage can be quickly detected. Further, any suitable circuit for operating a buzzer and/or a warning lamp may be formed. In this case, when the water leakage is detected by the water leakage sensor70, either of or both the buzzer and the warning lamp may be operated. Further, in this case, an electrical signal as a warning signal indicating the water leakage may be transmitted to control means (not illustrated) for the cutting apparatus10to thereby stop the cutting operation in case of emergency.

As illustrated inFIG.2, a water discharge hole47for discharging the water leaked is formed through the rear wall44at a position opposed to the predetermined low position on the bottom wall45where the detecting portion72of the water leakage sensor70is provided. Water discharging means50is connected to the outside surface of the rear wall44at the position where the water discharge hole47is formed. The water discharging means50includes a discharge pipe52and a cock54for opening and closing a passage in the discharge pipe52. Accordingly, when the water leaked is accumulated in the water pan4, the cock54is opened to thereby discharge the leaked water from the discharge pipe52. While the water discharge hole47is formed through the rear wall44in the preferred embodiment, the position of the water discharge hole47is not limited to the preferred embodiment. For example, the water discharge hole47may be formed through the bottom wall45at the position where the water leakage sensor70is provided. Further, the predetermined low position on the bottom wall45is not limited to the position opposed to the rear wall44as illustrated inFIG.2, and may be set to any arbitrary position.

As illustrated inFIG.2, four bosses46are formed at the four corners of the water pan4so as to project upward from the bottom wall45. The four bosses46are used to fix the water pan4to the bottom of the cutting apparatus10. More specifically, the water pan4is fixed through the four bosses46to the bottom of the housing2of the cutting apparatus10by using the four legs6. As illustrated inFIG.2, the bottom wall45of the water pan4is inclined with respect to a horizontal plane, and a height of each of the side wall42, the side wall43, and the rear wall44is different according to a horizontal position. Accordingly, the height of the boss46formed at the corner between the front wall41and the side wall42or the side wall43is different from the height of the boss46formed at the corner between the side wall43and the rear wall44and also different from the height of the boss46formed at the corner between the side wall42and the rear wall44.

A fixing structure using the legs6for fixing the water pan4to the housing2will now be described with reference toFIGS.2to4B.FIG.3is a partially cut-away perspective view illustrating the fixing structure at the corner between the front wall41and the side wall42, in which a part of the corner is cut away for convenience of explanation. As illustrated inFIG.3, each leg6includes a base60adapted to come into contact with a floor surface at a place where the cutting apparatus10is set, a threaded portion62integrally formed with the base60and having an external thread, and a tightening nut64threadedly engaged with the threaded portion62. An axial length of the threaded portion62of each leg6is larger than the height of the highest one of the four bosses46of the water pan4, that is, the height of the boss46formed at the corner between the rear wall44and the side wall42of the water pan4.

In mounting the water pan4to the bottom of the cutting apparatus10as illustrated inFIGS.2and3, the threaded portion62of each leg6is first inserted through each boss46of the water pan4from the under side thereof. That is, an inner diameter of each boss46is slightly larger than a diameter of the threaded portion62of each leg6, so that the threaded portion62is loosely fitted into each boss46so that an upper end portion of the threaded portion62projects from an upper end of each boss46. Four tapped holes2H are formed at the four corners of the bottom of the housing2so as to respectively correspond to the four bosses46of the water pan4. That is, each tapped hole2H has an internal thread adapted to engage with the external thread of the threaded portion62of each leg6. As illustrated inFIG.4A, the upper end portion of the threaded portion62inserted through each boss46is positioned at the corresponding tapped hole2H of the housing2, and the base60is then rotated to engage the upper end portion of the threaded portion62of each leg6into the corresponding tapped hole2H. Thus, the four legs6are fixed to the four corners of the bottom of the housing2. An amount of threaded engagement of the threaded portion62of each leg6with the corresponding tapped hole2H of the housing2may be set arbitrarily. In setting the cutting apparatus10, the height of the cutting apparatus10can be finely adjusted according to the amount of threaded engagement of the threaded portion62of each leg6with the corresponding tapped hole2H of the housing2. Thus, the horizontal position of the cutting apparatus10can be adjusted.

As illustrated inFIG.4A, the tightening nut64is threadedly engaged with the threaded portion62of each leg6. In mounting each leg6to the housing2, the tightening nut64is positioned near the base60as illustrated inFIG.4A. In this condition, the water pan4is supported through the legs6to the bottom of the cutting apparatus10. However, a gap P is formed between the bottom of the housing2and the upper end of each boss46, that is, between the bottom of the housing2and the upper ends of the front wall41, the side wall42, the side wall43, and the rear wall44.

After mounting the legs6with the water pan4to the bottom of the housing2, the tightening nut64is rotated to raise the water pan4with the tightening nut64, thereby bringing the upper end of each boss46into close contact with the bottom of the housing2as illustrated inFIG.4B. Accordingly, a closed space is defined between the inside surface of the water pan4and the bottom of the housing2. Thus, the water pan4is fixed to the bottom of the cutting apparatus10.

According to the preferred embodiment, the water pan4for receiving a water leaked is fixed to the bottom of the cutting apparatus10, so that it is unnecessary to perform an operation of preparing and setting a separate water pan. Accordingly, it is unnecessary to perform any extensive operation such that the cutting apparatus10is lifted by using a crane or the like, so as to set the water pan, and the water pan is next inserted into a space defined below the cutting apparatus10. Further, since the water pan4is fixed through the legs6to the housing2of the cutting apparatus10, the water pan4can be easily mounted to the housing2by mounting the legs6to the housing2. Further, the water pan4is fixed so that the bottom wall45is inclined with respect to a horizontal plane, and the detecting portion72of the water leakage sensor70is provided at the predetermined low position where the water leaked to the bottom wall45of the water pan4is collected. Accordingly, even when the water leakage occurs at any position in the cutting apparatus10, the water leakage can be detected quickly.

The present invention is not limited to the above preferred embodiment, and various modifications may be made. For example, while the present invention is applied to the cutting apparatus10in the above preferred embodiment, the present invention is applicable to any processing apparatus using a processing water, such as a grinding apparatus and a polishing apparatus.