JPH09162150A - Split wafer cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove the chips from a wafer surely by arranging a nozzle for delivering a cleaning liquid toward a wafer in parallel in the radial direction passing through the center of rotation of a rotator for holding a sheet pasted, to the circumferential fringe part thereof, with the wafer while directing the pasted face downward. SOLUTION: A flat tape-like rotator 12 having a central through hole 12a is coupled with the upper end of a rotary shaft 10. A cleaning liquid supply means, i.e., a pipe 14, is coupled with the upper end of a supply hose 13 and extends in the radial direction of the rotator 12 with a nozzle 15 opening to the upper circumferential surface thereof in the axial direction. A section 16 for holding an adhesive sheet at the upper end part is disposed at the outer circumferential part of the rotor 12 while being spaced apart therefrom. In practice, planarity of an adhesive sheet 18 is sustained by pasting a ring 19 to the circumferential fringe part of the adhesive sheet 18 being pasted while arranged a semiconductor pellet 17 and the adhesive sheet 18 is held by holding the ring 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field related to a cleaning device for removing cutting chips generated when a wafer is divided into individual pellets.

[0002]

2. Description of the Related Art In a semiconductor device, generally, a semiconductor pellet is mounted on a lead frame, electrodes on the semiconductor pellet are electrically connected to leads, and a main portion on the lead frame including the semiconductor pellet is made of resin or the like. The lead frame is covered with the covering material, and unnecessary portions of the lead frame exposed from the covering material are cut and removed to make each lead independent, and the leads are separately manufactured. Here, the semiconductor pellet is manufactured by cutting a semiconductor wafer on which a large number of semiconductor elements having the same pattern are formed from adjacent regions of the respective semiconductor elements and dividing the semiconductor wafer. That is, the semiconductor wafer is adhered to an adhesive sheet, the semiconductor wafer is fixed on the base by placing this adhesive sheet on the base, and the adjoining region of the semiconductor element using a cutting device such as a rotary blade. The semiconductor pellets are manufactured by mechanically cutting the wafer.However, during this work, water for cooling and cleaning is continuously provided on the semiconductor wafer to prevent seizure of the cutting tool and to quickly remove cutting chips. Can be applied. The semiconductor pellets thus individually divided are washed and dried while being stuck on the adhesive sheet while keeping the alignment state, and the good parts of the regular shape excluding the irregular part of the peripheral edge of the wafer are separated from the adhesive sheet one by one. It is peeled off and supplied to the manufacturing process of the semiconductor device. By the way, since cutting waste generated when a semiconductor wafer is cut with a cutting tool such as a rotary blade has conductivity, if it remains on the semiconductor pellet, it causes an electrical failure such as a short circuit or a decrease in withstand voltage. Therefore, the pressure and amount of cleaning water are finely adjusted to set the optimum value to set the best possible condition.However, if the size of the semiconductor pellet is small, the number of cutting grooves increases, which As a result, cutting chips increase and the possibility that they remain as foreign matter on the surface of the semiconductor pellet increases. In addition, the width of the cutting groove is narrowed by using a thin cutting blade, that is, the cutting margin is set as narrow as possible to widen the effective area. There is a problem that the force increases and it is difficult to peel off the cutting chips once attached to the semiconductor pellets. Further, in the power semiconductor pellet, the conductive pattern drawn around the pellet surface is also set to be thick, so that the unevenness of the pellet surface is remarkable compared to the small power semiconductor pellet, and cutting waste is easily caught on this unevenness and difficult to remove. There was a problem. In order to solve these problems, immediately after the cutting operation, the cleaning device shown in FIG. 6 is used to clean the surface of the semiconductor pellets adhered while keeping the aligned state on the adhesive sheet to remove foreign matters. The structure of this device will be described below. In the figure, reference numeral 1 denotes a rotary table fixed to the upper end of a rotary shaft 2 arranged in the vertical direction, and a large number of suction holes 1a are opened on the upper surface thereof. 3 is a pressure-sensitive adhesive sheet to which semiconductor pellets 4 each having an irregular shape located at the peripheral portion of a circular semiconductor wafer are attached in an aligned state on the peripheral portion.
It holds the semiconductor pellets 4 adsorbed thereon. Reference numeral 5 is a pipe (cleaning liquid supply means) having one end fixed to a rotary shaft 6 arranged on the side of the rotary table 1, an intermediate portion extending parallel to the upper surface of the rotary table 1, and the other end closed. A large number of nozzles 7 are opened on the surface facing 1 to reciprocate around the rotation shaft 6 within a certain angle. Although not shown, a water supply hose is connected to the pipe 5, and the cleaning liquid is discharged from the nozzle 7. In this device, for example, 4 Kg from a nozzle 7 is applied to a fan-shaped area on a large number of semiconductor pellets 4 which rotate at high speed on the rotary table 1 at a rotation speed of 1600 rpm, for example.
A cleaning liquid set to a pressure of / cm 2 is sprayed to lift up cutting chips (not shown) from the surface of the semiconductor pellets 4, and the floating cutting chips are shaken off by centrifugal force to be removed. Since no new cutting dust is supplied, the cutting dust is removed by setting the working time sufficiently long. This apparatus can shake off the water remaining on the surface of the semiconductor pellets 4 when the supply of the washing water is stopped, so that the apparatus can be dried in a short time.

[0003]

By the way, in the apparatus shown in FIG. 6, the semiconductor pellet 4 is sprayed with a high-pressure cleaning liquid so as to lift up the cutting chips adhering to the surface thereof.
The cleaning liquid flowing under the centrifugal force prevents the re-adhesion to the semiconductor pellets 4 and removes them. However, when the width of the cutting groove between the semiconductor pellets 4 and 4 on the sheet 3 becomes narrow, Even if the pressure is increased, the pressure applied to the cutting groove is substantially reduced, so the cutting debris remaining in the groove cannot be expelled from the groove and completely removed. In addition, there is a problem that the cutting waste adhered to the cutting groove, that is, the side wall of the semiconductor pellet is peeled off and falls on another semiconductor pellet to become a foreign substance. Further, there is a problem that fine cutting chips tend to adhere to the irregularities on the surface of the semiconductor pellet and, if electrostatically adhered, it is difficult to remove. For this reason, semiconductor pellets that have undergone cleaning work are sampled in adhesive sheet units to check the foreign matter adhesion status and adjust the cleaning conditions.However, the surface condition of semiconductor pellets and the size of semiconductor pellets are adjusted. It was not possible to determine the conditions that can completely solve the above problems, because the cleaning conditions differ subtly depending on the width of the cutting groove, the water pressure of the cleaning water, the flow rate, the temperature, and so on.

[0004]

SUMMARY OF THE INVENTION The present invention has been proposed for the purpose of solving the above-mentioned problems, and a sheet having a wafer which is rotated around an axis of rotation arranged in the up-and-down direction and whose periphery is adhered to the wafer is formed on the wafer. A rotating body having a sheet holding portion for holding the sticking surface downward and at least one radial direction passing through the center of rotation of the rotating body, the cleaning liquid having nozzles for ejecting the cleaning liquid toward the wafer opened. Provided is a cleaning device for divided wafers, which is provided with a supply means. In this case, the nozzle for ejecting the cleaning liquid toward the wafer can be moved in the direction intersecting the arrangement direction. Also, the discharge strength of the cleaning liquid discharged from the nozzle can be made different in the radial direction of the rotating body. Further, the rotation axis of the rotating body can be tilted. In this case,
The direction of the nozzle is set so that the cleaning liquid ejected from the nozzle is supplied to the region that rotates upward from below the wafer surface in a direction that forms an acute angle with the wafer.
Also, a means for removing static electricity charged on the wafer can be provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.
It will be explained first. In the figure, 8 is a base, 9 is a base 8
The bearing 10 arranged above is a hollow rotary shaft which is rotatably supported by the bearing 9 and whose lower end is supported by the base 8 via a bearing 11, and forms an annular belt receiving groove 10a at the peripheral edge of the lower end. . In the illustrated example, reference numeral 12 denotes a flat table-shaped rotating body having a through hole 12a formed in the center thereof, which is connected to the upper end of the rotating shaft 10. 13 is a supply pipe for penetrating the base 8 and coaxially arranged in the rotary shaft 10 and having an upper end for supplying the cleaning liquid inserted into the through hole 12a of the rotating body 12, and 14 is connected to the upper end of the supply hose 13, A nozzle (cleaning liquid supply means) extending in the radial direction of the rotating body 12 has a nozzle 15 axially opened on the upper surface of the outer periphery thereof. Reference numeral 16 denotes a sheet holding portion which is arranged at an outer peripheral portion of the rotating body 12 and is separated from the outer circumferential portion, and which holds an adhesive sheet at an upper end portion thereof.
Is attached to maintain the flatness of the adhesive sheet 18, and the ring 19 is retained to retain the adhesive sheet 18. Reference numeral 20 denotes a belt receiving groove 1 for the motor and the rotary shaft 10 not shown.
An endless belt mounted between the rotating body 12 and 0a transmits the rotation of the motor to the rotating shaft 10 to rotate the rotating body 12. Reference numeral 21 denotes a cover that surrounds the rotating body 12 and prevents the cleaning liquid from splashing to an undesired portion. The operation of this device will be described below. First, the semiconductor wafer attached to the adhesive sheet 18 is cut into individual semiconductor pellets 17, and the ring 19 is attached to the peripheral edge of the adhesive sheet 18 to which the semiconductor pellets 17 are attached while keeping the aligned state. The adhesive sheet 18 is attached to the rotating body 12 by the sheet holding unit 16 so that the semiconductor pellet 17 faces the rotating body 12 while maintaining the flatness of the adhesive sheet 18. Next, when the motor is started and the rotary shaft 10 is rotated, the semiconductor pellets 17 attached to the adhesive sheet 18 are rotated while interlocking with the rotating body 12 while maintaining the aligned state. Furthermore, the cleaning liquid is supplied from the hose 13 to the pipe 14, the cleaning liquid is discharged from the nozzle 15, and sprayed onto the rotating semiconductor pellets 17. The pressure of the cleaning liquid is set to a strength lower than the strength for peeling the semiconductor pellet 17 from the adhesive sheet 18. Also,
When the rotation speed of the rotating body 12 is a low speed rotation of about 100 rotations per minute, the pressure is set to exceed 5 kg per square cm, but the pressure is reduced as the rotation speed increases, for example, 16 minutes per minute.
It is set to 4 kg / square cm at the time of 00 rotations. Since the cleaning liquid sprayed on the semiconductor pellets 14 has a different peripheral velocity depending on the radial position of the rotating body 12, the movement path of the cleaning liquid seen from the bottom surface moves spirally from the inside to the outside. Since gravity acts on the cleaning liquid sprayed on the semiconductor pellets 17, the cleaning liquid that has collided with the semiconductor pellets 14 spreads horizontally while adhering to the surface against the gravity for a certain period of time, then horizontally moves, and then falls while drawing a parabola. . Therefore, the cleaning liquid sprayed on the semiconductor pellets 17 at high pressure collides with the cutting chips moving at a relatively high speed, peels off the cutting chips, and lifts them off the exposed surface of the semiconductor pellets or the adhesive sheet. It is dropped and removed without being reattached on the semiconductor pellet by the fresh cleaning liquid which is continuously supplied. Further, since the excess cleaning liquid is removed by the centrifugal force and the cutting chips attached to the semiconductor pellets 17 or the adhesive sheet 18 are exposed, the cleaning liquid supplied from the nozzle 15 directly hits the cutting chips, and the peeling can be efficiently performed. The pipes 14 are arranged in one radial direction passing through the center of rotation of the rotating body 12. However, the cleaning liquid hitting the semiconductor pellets 17 spirally spreads from the inside to the outside and is supplied near the center. Since some of the nozzles pass through the center of rotation, it is not necessary to position one of the many nozzles arranged in the radial direction at the center of rotation. Further, the nozzle for ejecting the cleaning liquid toward the wafer can be reciprocated in the range from the center of rotation to the outer circumference of the wafer in the direction intersecting with the arrangement direction, whereby the nozzle is located away from the center of the wafer. Cleaning liquid can be supplied to the cutting grooves along the forming direction during rotation, and cleaning can be performed on all the cutting grooves on one wafer under almost the same conditions. It becomes possible to wash. Furthermore, the pressure of the cleaning liquid can be adjusted according to the position of the nozzle 15 in accordance with the peripheral speeds that differ between the center and the peripheral edge of the rotating body 12. That is, the nozzle 15 opened in the pipe 14
The discharge strength of the cleaning liquid can be changed step by step for each nozzle adjacent to the nozzle farther from the center of rotation toward the nozzle farther from the center of rotation, or for a plurality of nozzles as a set, and the discharge strength of the cleaning liquid can be changed stepwise. When the nozzles are moved in a direction intersecting the arrangement direction of the nozzles 15, the discharge intensity of the cleaning liquid can be adjusted according to the position from the rotation center of the pipe 14. Further, the nozzle 15 may be formed not only in the axial direction of the pipe 14 but also at one end of the pipe 14. Also,
In the apparatus shown in FIG. 1, the rotating body 12 was driven by the belt 20, but the rotating body 12 was turned upside down together with the nozzle in a state where the rotating shaft was directly connected to the motor and the divided semiconductor wafer was suction-held. You can also do it.

[0006]

EXAMPLE An example of the present invention will be described below with reference to FIG.
In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals, and overlapping description will be omitted. In the figure, the difference from the device of FIG. 1 is the rotating shaft 10 of the rotating body 12.
Then, specifically, only the rotating shaft 10 is tilted, and the other parts are the same as those in the apparatus shown in FIG. That is, the inclination angle of the rotating shaft 12 of this device is more than 0 degree and less than 90 degrees with respect to the horizontal plane, preferably 15 degrees to 85 degrees.
It is set to every. In this device, as in the device shown in FIG. 1, the excess cleaning liquid is removed from the surface of the semiconductor pellet 17 by the centrifugal force, and the cutting chips moving to the position of the nozzle 15 are exposed, but they are discharged from the nozzle 15 and spread on the semiconductor pellet 17. The cleaning liquid is spread differently before and after the rotating body 12 in the moving direction, and in the apparatus shown in FIG. 1, the cleaning liquid 22 that hits the semiconductor pellets 17 vertically as shown in FIG. The pressure-sensitive adhesive sheet 18 is moved in contact with the pressure-sensitive adhesive sheet 18, including the parabolic drop, and the angle S1 from the pressure-sensitive adhesive sheet 18 at a position of a distance L12 that is sufficiently shorter than the distance L11 behind in the rotation direction.
And fall into a parabola. On the other hand, in the apparatus shown in FIG. 2, the cleaning liquid 22a that spreads forward in the rotation direction contacts the adhesive sheet for a distance L21 longer than the distance L11 and finally moves in a parabola, but drops backward in the rotation direction. The spread cleaning liquid 22b has a distance L2 shorter than the distance L12.
It is separated from the adhesive sheet 18 at the position of 2 and at an angle S2 larger than the angle S1. Therefore, the cutting chips to be removed are directly hit by the cleaning liquid 22 in a short time after receiving the force to be lifted from the semiconductor pellets 17 or the adhesive sheet 18, and the cutting chips firmly adhered by static electricity can be efficiently separated and removed. FIG. 5 shows a modification of the present invention. 2 is different from the device in FIG. 2 in the discharge direction of the nozzle 15, and the cleaning liquid 22 discharged from the nozzle 15 makes an acute angle with respect to the adhesive sheet 18 in a region where the rotating adhesive sheet 18 moves upward from below. It is characterized in that the direction of the nozzle 15 is set so as to be supplied in the direction. Thereby, the semiconductor pellet 17
Since the relative speed at which the cutting waste adhering to the adhesive sheet 18 and the cleaning liquid 22 face each other can be increased and the cleaning liquid can directly hit from the front in the moving direction of the cutting waste, the cutting waste can be efficiently separated and removed. Further, by adding a means for removing static electricity charged on the semiconductor pellets 17 and the adhesive sheet 18 to the apparatus shown in FIGS. 1, 2 and 5, it is possible to more easily remove cutting chips. Incidentally, the present invention is not limited to the above examples, for example, the semiconductor pellet wafer was described, but a thin plate-shaped wafer is sizing, not limited to the semiconductor as long as it can be divided into pellets of a fixed size by cutting. Needless to say, it can be applied to an insulating plate made of ceramics or a flat plate made of a metal plate.

[0007]

As described above, according to the present invention, it is possible to surely remove the cutting chips generated when the semiconductor wafer is cut and divided, and it is possible to prevent the problems caused by the cutting chips from occurring.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a cleaning apparatus showing an embodiment of the present invention.

FIG. 2 is a side sectional view showing an embodiment of the present invention.

FIG. 3 is a side sectional view of an essential part showing a state of discharged cleaning liquid by the apparatus in FIG.

FIG. 4 is a side sectional view of an essential part showing the state of the discharged cleaning liquid by the apparatus shown in FIG.

FIG. 5 is a side sectional view of an essential part showing a modified example of the present invention.

FIG. 6 is a side sectional view showing an example of a conventional wafer cleaning apparatus.

[Explanation of symbols]

 10 Rotating Shaft 12 Rotating Body 14 Cleaning Liquid Supplying Means (Pipe) 15 Nozzle 16 Sheet Holding Means 17 Divided Wafer (Semiconductor Pellet) 18 Adhesive Sheet

Claims (6)

[Claims] 1. A rotating body having a sheet holding portion which rotates about a rotation axis arranged in a vertical direction and holds a sheet having a wafer adhered on a peripheral portion with its wafer adhering surface facing downward, and a rotating body. A divided wafer cleaning apparatus, comprising: a cleaning liquid supply unit that is arranged parallel to at least one radial direction passing through a center of rotation of a body and has a nozzle that discharges the cleaning liquid toward the wafer. 2. The divided wafer cleaning apparatus according to claim 1, wherein a nozzle position for ejecting the cleaning liquid toward the wafer is movable. 3. The divided wafer cleaning apparatus according to claim 1, wherein the discharge strength of the cleaning liquid discharged from the nozzle is varied in the radial direction of the rotating body. 4. The divided wafer cleaning apparatus according to claim 1, wherein the rotating shaft of the rotating body is inclined. 5. The direction of the nozzle is set so that the cleaning liquid discharged from the nozzle is supplied to a region of the surface of the wafer which rotates upward from below in a direction forming an acute angle with respect to the wafer. The divided wafer cleaning apparatus according to claim 4. 6. The divided wafer cleaning apparatus according to claim 1, further comprising means for removing static electricity charged on the wafer.