JP6439608B2 - Chamfering method and chamfering apparatus - Google Patents

Description

  The present invention relates to a wafer chamfering method and a chamfering apparatus.

  In the manufacture of silicon wafers, silicon wafers sliced thinly from the state of a silicon single crystal ingot are usually chamfered at the outer periphery of the wafer in order to prevent cracking or chipping of the outer edge due to handling in each subsequent process. Processing.

  The chamfering of the wafer can be performed using, for example, a contouring method. The contouring method is a method in which chamfering is performed by grinding the outer peripheral portion of a wafer by holding the wafer on a processing table while rotating the grinding wheel while rotating it, and grinding the outer peripheral portion of the wafer (for example, Patent Document 1). reference). Usually, a coolant is appropriately supplied to a processing unit that performs grinding in order to cool a wafer and a grindstone and to remove grinding waste generated by the processing.

JP 2001-219346 A

  However, with the recent increase in diameter of wafers, the amount of grinding in the chamfering process has greatly increased. Along with this, the amount of generated dirt such as grinding debris in the processing section increases, and it is not possible to sufficiently remove the dirt such as grinding debris only by supplying coolant to the processing section that is generally performed. Dirt such as grinding scraps remaining on the outer periphery of the wafer causes various adverse effects in the subsequent process. In particular, there is a problem that the inspection accuracy is deteriorated in the intermediate inspection process for confirming the chamfered shape.

  Further, in the contouring type chamfering process, the dirt adhering to the outer peripheral part of the wafer is not only directly attached to the wafer at the processing part. In addition, a large amount of dirty coolant liquid containing grinding debris flows out to the wafer surface during processing, and when the coolant flows down from the outer periphery of the wafer due to the inertial force of the rotation of the wafer, the debris becomes dirty. May adhere. Therefore, as in the prior art, merely supplying concentrated coolant to the processing portion is insufficient to prevent or remove dirt such as grinding dust adhering to the processing portion on the outer periphery of the wafer during chamfering. As described above, there is a problem that it is difficult to sufficiently remove the grinding dust that has increased due to the increase in the grinding amount accompanying the increase in the diameter of the wafer.

  The present invention has been made in view of the above-described problems. A chamfering method and a chamfering apparatus capable of sufficiently removing dirt such as grinding scraps even when the generation amount of grinding scraps and the like is increased in chamfering processing. The purpose is to provide.

  In order to achieve the above object, the present invention holds a wafer on a processing table, contacts the rotating grindstone on the outer periphery of the wafer while rotating the processing table and rotating the wafer, A chamfering method for chamfering by grinding an outer peripheral portion, and supplying a coolant to a processing portion in contact with the outer peripheral portion of the wafer and the grindstone during the grinding, and other than the processing portion A chamfering method is provided, wherein cleaning water is supplied to an outer peripheral portion of the wafer.

  In this way, not only supplying coolant to the processing part, but also supplying cleaning water to the outer peripheral part of the wafer other than the processing part to perform cleaning on almost the entire periphery of the outer peripheral part of the wafer being processed. Can do. For this reason, even when the amount of grinding scrap increases, dirt on the outer peripheral portion of the wafer can be sufficiently removed, and adhesion of dirt can be prevented. In particular, the dirt adhering to the edge part of the outer peripheral part of the wafer can be effectively removed, and the adhesion of the dirt can be prevented.

  At this time, it is preferable to clean the front and back surfaces of the wafer with the cleaning water.

  Thereby, the dirty coolant liquid containing the grinding waste etc. which remain | survive on the wafer front and back can also be removed simultaneously.

  At this time, while the grindstone is rotating, the cleaning water is always supplied to the outer peripheral portion of the wafer other than the processing portion and the front and back surfaces of the wafer except when the wafer is attached to and detached from the processing table. Is preferred.

  In this way, in the chamfering process, the cleaning effect can be further enhanced if the cleaning water is always supplied except when the wafer is attached or detached.

  In order to achieve the above object, the present invention includes a processing table that can be rotated while holding a wafer, and a rotatable grindstone, and the wafer held by the processing table while rotating the wafer. A chamfering device for chamfering by bringing the rotating grindstone into contact with the outer peripheral portion of the wafer and grinding the outer peripheral portion of the wafer, wherein the outer peripheral portion of the wafer and the grindstone are in contact with each other There is provided a chamfering processing apparatus comprising: a coolant supply unit that supplies a coolant; and a cleaning water supply unit that supplies cleaning water to an outer peripheral portion of the wafer other than the processing unit.

  In such a case, not only the coolant is supplied to the processing part, but also cleaning water is supplied to the outer peripheral part of the wafer other than the processing part to clean the entire peripheral part of the wafer being processed. Cleaning can be performed. For this reason, even when the amount of grinding scrap increases, dirt on the outer peripheral portion of the wafer can be sufficiently removed, and adhesion of dirt can be prevented. In particular, the dirt adhering to the edge part of the outer peripheral part of the wafer can be effectively removed, and the adhesion of the dirt can be prevented.

  At this time, it is preferable that the cleaning water supply unit can clean the front and back surfaces of the wafer with the cleaning water.

  If it is such, the dirty coolant liquid containing the grinding waste etc. which remain on the wafer front and back can also be removed simultaneously.

  At this time, the cleaning water supply unit is always on the outer peripheral portion of the wafer other than the processing unit and on the front and back surfaces of the wafer except when the wafer is detached from the processing table while the grindstone is rotating. It is preferable that the washing water can be supplied.

  If it is such, in a chamfering process, since cleaning water can be always supplied other than at the time of attachment or detachment of a wafer, a cleaning effect can be improved more.

  At this time, the washing water supply unit is an annular member having an open part, and may have a plurality of washing water jets for ejecting the washing water on the inner peripheral surface.

  If it is such, a washing | cleaning liquid can be reliably supplied over the substantially perimeter of the outer peripheral part of a wafer.

  The chamfering method and the chamfering apparatus of the present invention can sufficiently remove the dirt on the outer peripheral portion of the wafer even when the amount of grinding waste increases in the chamfering process, and the adhesion of dirt. Can be prevented.

It is a top view which shows the outline of the principal part of the chamfering processing apparatus of this invention. It is a side view which shows the outline of the principal part of the chamfering processing apparatus of this invention.

  Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.

  As described above, the amount of grinding in the chamfering process has increased with the recent increase in wafer diameter, and there has been a problem that dirt such as grinding dust cannot be removed sufficiently.

  Therefore, the present inventor has intensively studied to solve such problems. As a result, in the chamfering process, in addition to supplying coolant to the processing part, it was found that the cleaning liquid can be effectively supplied to the outer peripheral part of the wafer other than the processing part, thereby completing the present invention. It was.

  First, a chamfering apparatus of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the chamfering apparatus 1 of the present invention includes a processing table 2 that can rotate while holding a wafer W, and a grindstone 3 that can rotate. The number of grindstones 3 may be one or more. 1 and 2 illustrate a case where two grindstones 3a and 3b are provided.

  In such a chamfering processing apparatus 1, the rotating grindstone 3 is brought into contact with the outer peripheral portion 4 of the wafer W while rotating the wafer W held by the processing table 2. Thus, the chamfering process is performed by grinding the outer peripheral portion 4 of the wafer W at the processing portion 5 in the outer peripheral portion 4 of the wafer W.

  The chamfering apparatus 1 of the present invention further includes a coolant supply unit 6 that supplies coolant to the processing unit 5 in which the outer peripheral portion 4 of the wafer W and the grindstone 3 are in contact, and the outer periphery of the wafer W other than the processing unit 5. A cleaning water supply unit 7 that supplies cleaning water to the unit 4 is provided. The coolant supply part 6 can consist of a nozzle connected with the water supply source 8, for example. As the coolant and cleaning water, for example, pure water can be used. Then, like the coolant supply unit 6, the cleaning water supply unit 7 is supplied with pure water from the water supply source 8 and can supply the pure water to the outer peripheral portion 4 of the wafer W as cleaning water.

  At this time, as shown in FIG. 1, the washing water supply unit 7 can be an annular one having an open part 7 a. And the cyclic | annular washing water supply part 7 shall have multiple washing water outlets 7c which eject washing water to the internal peripheral surface 7b. For example, the cleaning water supply unit 7 can be positioned outside the processing table 2 within a range of 45 ° to 315 ° from the grindstone 3 with respect to the center of the processing table 2. With such a cleaning water supply unit 7, the cleaning water can be ejected from the plurality of cleaning water ejection ports 7 c facing the wafer W toward the wafer outer peripheral portion 4.

  Moreover, in this invention, it is preferable that the washing water supply part 7 can wash | clean the front and back of the wafer W with washing water. By supplying the cleaning water to the front and back surfaces of the wafer, it is possible to reliably clean the contaminated coolant liquid containing the grinding scraps and the like staying on the front and back surfaces of the wafer.

  For example, the cleaning water can be supplied so as to reach the front and back surfaces of the wafer W while cleaning the outer peripheral portion 4 of the wafer W. In this case, the cleaning liquid moves the front and back surfaces of the wafer W by the rotation of the wafer W, and cleans the front and back surfaces. As a result, it is possible to remove and prevent adhesion of both the dirt directly adhering to the outer periphery of the wafer and the dirt reaching the outer periphery of the wafer via the front and back surfaces of the wafer.

  In order to clean the front and back surfaces of the wafer W with the cleaning liquid, for example, by increasing the spraying pressure of the cleaning liquid from the cleaning water outlet 7c of the cleaning water supply unit 7 or adjusting the spray angle, What is necessary is just to make a washing | cleaning liquid reach the front and back in addition to the outer peripheral part 4. In addition, the cleaning water supply unit 7 has a nozzle or the like that can inject the cleaning liquid directly onto the front and back surfaces of the wafer W from above and below the wafer W in addition to the cleaning water jet 7c as described above. It is also good.

  Further, in the present invention, the cleaning water supply unit 7 is configured such that the outer peripheral portion 4 of the wafer W other than the processing unit 5 and the surface of the wafer W are removed during the rotation of the grindstone 3 except when the wafer W is detached from the processing table 2. It is preferable that cleaning water can be always supplied to the back surface. In the chamfering process, if the cleaning water is always supplied to the wafer W except when the wafer W is attached / detached, the dirt such as grinding debris generated by grinding is removed immediately so that the dirt does not stick over time. can do. As a result, during the chamfering process, the effect of preventing the adhesion of dirt to the wafer can be maintained.

  The processing table 2 is rotated in the θ direction of FIGS. 1 and 2 about the center of the processing table 2 as a rotation axis by a rotation unit such as a θ-axis motor and a θ spindle below the stage on which the wafer W is placed. To do. The processing table 3 can be moved in the X-axis direction of FIGS. 1 and 2 by, for example, an X-axis driving means such as a ball screw and a stepping motor.

  Further, the upper surface of the stage on which the wafer W of the processing table 2 is placed can be, for example, a suction surface connected to the vacuum source 9, and the wafer W to be chamfered can be vacuum-sucked and held.

  The grindstone 3 is fixed to, for example, a grindstone rotating unit including a grindstone rotating motor and a rotating shaft. And the grindstone 3 rotates by rotation of the motor for grindstone rotation. Further, the grindstone 3 can be moved in the Z-axis direction of FIG. 2 by Z-axis driving means such as a ball screw and a stepping motor.

  The coolant supply unit 6 is attached to, for example, the grindstone rotating unit described above, and the coolant liquid can be constantly supplied to the grindstone 3 and the processing unit 5 of the wafer W.

  With the chamfering apparatus of the present invention as described above, not only supplying coolant to the processing part, but also supplying cleaning water to the outer peripheral part of the wafer other than the processing part to clean the outer periphery of the wafer being processed. Cleaning can be performed over almost the entire circumference of the section. For this reason, even when the amount of grinding scrap increases, dirt on the outer peripheral portion of the wafer can be sufficiently removed, and adhesion of dirt can be prevented. In particular, the dirt adhering to the edge part of the outer peripheral part of the wafer can be effectively removed, and the adhesion of the dirt can be prevented. Further, since the wafer chamfered by this apparatus has little dirt, cleaning after chamfering can be simplified.

  Subsequently, the chamfering method of the present invention will be described by taking the case of using the chamfering apparatus 1 of the present invention as an example.

  When using the chamfering processing apparatus 1 of the present invention shown in FIGS. 1 and 2, first, the processing table 2 holding the wafer W to be processed by suction is rotated in the θ direction. Thereby, the wafer W is rotated. Subsequently, the processing table 2 is moved in the X-axis direction to approach the rotating grindstone 3, and the rotating grindstone 3 is brought into contact with the outer peripheral portion of the wafer W. Thus, grinding is started in the processing unit 5 from the contacted state.

  In the present invention, during this grinding, coolant is supplied to the processing portion 5 where the outer peripheral portion 4 of the wafer W and the grindstone 3 are in contact, and cleaning water is supplied to the outer peripheral portion of the wafer W other than the processing portion 5. . As a result, it is possible to remove and prevent adhesion of both the dirt directly adhering to the outer periphery of the wafer and the dirt reaching the outer periphery of the wafer via the front and back surfaces of the wafer.

  At this time, it is preferable to clean the front and back surfaces of the wafer W with cleaning water. By supplying the cleaning water to the front and back surfaces of the wafer W, the contaminated coolant liquid containing the grinding scraps and the like remaining on the front and back surfaces of the wafer W can also be reliably removed. In order to clean the front and back surfaces of the wafer simultaneously with the outer peripheral portion, the design change of the cleaning water supply unit 7 described above may be performed.

  Further, by moving the processing table 2 in the X-axis direction at an arbitrary speed while moving the grindstone 3 at an arbitrary speed in the Z-axis direction shown in FIG. Can be processed.

  In the present invention, during the rotation of the grindstone 3, cleaning water is always supplied to the outer peripheral portion 4 of the wafer W other than the processing portion 5 and the front and back surfaces of the wafer W except when the wafer W is detached from the processing table 2. It is preferable to do. In the chamfering process, for example, if cleaning water is always supplied to the wafer W except when the wafer W is attached / detached, the dirt such as grinding dust generated by grinding will not be fixed over time. Can be removed. As a result, during the chamfering process, the effect of preventing the adhesion of dirt to the wafer can be maintained.

  After chamfering the wafer W as described above, the wafer W can be cleaned. For cleaning the wafer W, it is preferable to perform simple cleaning after transfer to a simple water cleaning unit attached to a general chamfering apparatus. For cleaning the wafer W, for example, spin cleaning and drying while water is applied to the wafer W are preferable. Thus, since the cleaning performed on the wafer W after the chamfering process is performed by the chamfering method of the present invention can be completed by water cleaning, it is simpler than the case of cleaning by chemical cleaning or the like, Low cost.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples.

(Example)
First, using a chamfering apparatus of the present invention as shown in FIGS. 1 and 2, 30 single-crystal silicon wafers were chamfered according to the chamfering method of the present invention. As the silicon wafer, a wafer having a diameter of 300 mm cut out from a silicon single crystal ingot was used. The grindstone 3a and the grindstone 3b were resin bond grindstones having diamond abrasive grains. The diamond abrasive grains were set to grain size # 3000 in order to obtain a precise chamfered shape. The machining allowance for chamfering was set to 80 μm in order to obtain a precise chamfered shape. The flow rate of the coolant liquid was set to 2 L / min or more in general. The flow rate of the cleaning water supplied to the annular cleaning water supply unit 7 was set to 3 L / min or more. Note that pure water was used as the coolant and cleaning water.

  Next, the silicon wafer after the grinding was detached from the processing table and transferred to the water cleaning unit, and then simple cleaning was performed. For cleaning, spin cleaning and drying were performed while water was applied to the wafer.

  Next, the presence or absence of contamination on the chamfered surface of the silicon wafer was confirmed. Table 1 shows the percentage of silicon wafers with dirt on the chamfered surface after spin cleaning and drying. In addition, the presence or absence of dirt was confirmed by visually observing the silicon wafer after completion of the spin cleaning and drying with a scope.

  As shown in Table 1 below, in the example, 0 (0%) of 30 silicon wafers were contaminated.

(Comparative example)
Example of chamfering the wafer by the conventional chamfering method, that is, supplying the coolant (pure water) to the processing part without supplying the cleaning liquid when grinding the outer peripheral surface of the silicon wafer. Chamfering, spin cleaning, and drying were performed under the same conditions. Similarly to the example, the percentage of silicon wafers on which the chamfered surface was contaminated after spin cleaning and drying was calculated.

  As a result, as shown in Table 1, 24 out of 30 wafers processed (80%) were contaminated.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

DESCRIPTION OF SYMBOLS 1 ... Chamfering processing apparatus, 2 ... Processing table, 3, 3a, 3b ... Grinding stone,
4 ... Outer peripheral part of wafer W, 5 ... Processing part of wafer W, 6 ... Coolant supply part,
7 ... Washing water supply part, 7a ... Opening part, 7b ... Inner peripheral surface, 7c ... Washing water spout,
8 ... Water supply source, 9 ... Vacuum source, W ... Wafer.

Claims (6)

A chamfering process in which a wafer is held by a processing table, a rotating grindstone is brought into contact with the outer peripheral portion of the wafer while the processing table is rotated to rotate the wafer, and the outer peripheral portion of the wafer is ground to be chamfered. A method,
While supplying the coolant to the processing portion where the outer peripheral portion of the wafer is in contact with the grindstone during the grinding, the cleaning water is supplied to the outer peripheral portion of the wafer other than the processing portion ,
The cleaning water supply is performed using a cleaning water supply unit that is an annular cleaning water supply unit having an open portion, and has a plurality of cleaning water jets for ejecting the cleaning water on the inner peripheral surface. A chamfering method characterized by the above.   The chamfering method according to claim 1, wherein the front and back surfaces of the wafer are also cleaned with the cleaning water.   During the rotation of the grindstone, the cleaning water is always supplied to the outer peripheral portion of the wafer other than the processing portion and the front and back surfaces of the wafer except when the wafer is detached from the processing table. The chamfering method according to claim 1 or 2. A rotating processing table that holds a wafer and a rotating grindstone, and the rotating grindstone contacts the outer peripheral portion of the wafer while rotating the wafer held by the processing table, A chamfering device for chamfering by grinding the outer periphery of
Furthermore, a coolant supply unit that supplies a coolant to a processing portion in which the outer peripheral portion of the wafer and the grindstone are in contact with each other
All SANYO comprising a cleaning water supply unit for supplying washing water to the outer peripheral portion of the wafer other than the processing unit,
Washing water supply portion is of annular having an opening, chamfering apparatus according to claim der Rukoto which has a plurality of washing water ejecting port for ejecting the washing water to the inner circumferential surface.   The chamfering apparatus according to claim 4, wherein the cleaning water supply unit can clean the front and back surfaces of the wafer with the cleaning water. During the rotation of the grindstone, the cleaning water supply unit always supplies the cleaning water to the outer peripheral portion of the wafer other than the processing unit and to the front and back surfaces of the wafer except when the wafer is attached to and detached from the processing table. The chamfering apparatus according to claim 4 or 5, wherein the chamfering apparatus can be supplied.

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