TWI793290B - Grinding device, wafer grinding method, and wafer manufacturing method - Google Patents

Abstract

The invention provides a grinding device and a wafer grinding method, comprising a grinding head; a fixed disc, which is attached with a grinding cloth; a loading table, which is used to install the wafer on the grinding head; an unloading table, which is used To peel off the wafer from the grinding head, the grinding device is used to grind the wafer supported by the grinding head, wherein the grinding device further includes a local grinding pad that can move up and down, which is smaller than the wafer, and the local grinding pad faces the grinding head. While rising to bring the wafer supported by the polishing head into contact with the local polishing pad, the polishing head supporting the wafer is rotated to locally polish the outer periphery of the wafer in a concentric circle, thereby enabling CMP such as DSP processing. Grinding before processing and shape matching in CMP processing are improved compared to the past, and the wafer shape after CMP processing is flattened.

Description

Grinding device, wafer grinding method, and wafer manufacturing method

The invention relates to a grinding device, a wafer grinding method and a wafer manufacturing method.

The general process of semiconductor wafer polishing is to perform secondary polishing and finishing polishing by single-side polishing (CMP) after double-side polishing (DSP) processing.

FIG. 11 is a diagram showing an example of a conventional wafer polishing flow. After the wafer is DSP processed (S1'), the secondary grinding process (S3') is performed, and finally the finishing grinding process (S5') is performed. The secondary grinding process may be repeated more than two times if necessary (S4').

Since the wafer is shaped by the sum of the removal amount of DSP processing and CMP processing, the variation of the DSP shape greatly affects the variance of the flatness of the wafer.

CMP processing is performed on wafers processed by DSP. In DSP processing, the outer peripheral shape of the wafer is manufactured with the aim of a warped shape. In the subsequent CMP process, the overall aim is to conform to the previous shape, but in order to prevent the outermost peripheral part of the wafer from drooping, it is set so that it becomes a slightly warped shape. Therefore, shape matching in DSP and CMP may not be performed smoothly, and the shape of DSP may be deteriorated in CMP processing. [Prior Technical Literature] [Patent Document]

[Patent Document 1] Japanese International Publication No. 2010/023829 [Patent Document 2] Japanese Unexamined Patent Publication No. 2012-35393 [Patent Document 3] Japanese International Laid-Open Publication No. 2013/001719

[Problem to be solved by the invention] As mentioned above, in the past, the outer peripheral shape of the wafer processed by grinding such as double-side polishing (DSP) processing has become a raised shape, because the outermost peripheral portion of the wafer is set in a raised shape during CMP processing, and Grinding before CMP processing such as DSP processing and shape matching during CMP processing may not be performed smoothly, and the shape of the grinding process by DSP processing or the like may deteriorate during CMP processing. In order to improve the quality of wafers after CMP processing, it is necessary to match the polishing process before CMP processing such as DSP processing with the shape during CMP processing.

In view of the above problems, the present invention provides a grinding device and a wafer grinding method, which can make the shape matching between the grinding process before the CMP process such as DSP processing and the shape matching in the CMP process more improved than in the past, and the CMP process after the CMP process The wafer shape is flattened. [Technical means to solve the problem]

In order to solve the above problems, the present invention provides a grinding device, which includes a grinding head, which is used to support a wafer; a fixed plate, which is attached with a grinding cloth for grinding the wafer; a loading table, which is used for The grinding head mounts the wafer; an unloading table is used to peel off the wafer from the grinding head, and the grinding device grinds the wafer supported by the grinding head, wherein the grinding device further includes a device capable of moving up and down and relatively The wafer is a small local polishing pad. When the local polishing pad is relatively raised toward the polishing head so that the wafer supported by the polishing head is in contact with the local polishing pad, the wafer supporting the wafer is The polishing head is rotated to locally polish the outer peripheral portion of the wafer concentrically.

With such a polishing device, even if the outer peripheral part of the wafer is made into a warped shape, it can be performed in CMP processing using a polishing device (CMP device) that has a function of correcting a part of the wafer (the outer peripheral part of the wafer). Shape matching makes it possible to obtain a highly flat wafer system.

At this time, it is preferable that the local polishing pad is ground by contacting the outer periphery of the wafer with the center of the local polishing pad.

According to such a polishing apparatus, it is possible to more reliably and uniformly polish the warped shape of the outer peripheral portion of the wafer.

In addition, at this time, the grinding device includes a back pad cleaning table that can move up and down for cleaning the grinding head, the local polishing pad is arranged on the back pad cleaning table, and the back pad cleaning table and the back pad cleaning table It is preferable that the partial polishing pad can move up and down separately.

With such a polishing apparatus, the warped shape of the outer peripheral portion of the wafer can be easily corrected by disposing the local polishing pad on the back pad cleaning table of the polishing apparatus, and shape matching in CMP processing becomes possible.

In addition, the present invention provides a wafer grinding method, which is a wafer grinding method using the grinding device of the present invention, wherein before performing comprehensive single-side grinding of the wafer, the partial grinding pad is opposed to the grinding head. While the wafer supported by the polishing head is raised to contact the local polishing pad, the polishing head supporting the wafer is rotated to locally polish the outer periphery of the wafer concentrically.

If it is such a grinding method, the outer peripheral part of the wafer, which has been made into a warped shape by DSP in the past and cannot be corrected after CMP processing, and the flatness deteriorates, is used with a part of the corrected wafer (wafer's The function of the polishing device (CMP device) of the peripheral part) can be locally polished to perform shape matching in CMP processing, and it is possible to obtain a highly flat wafer system.

In addition, at this time, the local polishing pad is preferably ground so that the outer periphery of the wafer is in contact with the center of the local polishing pad.

According to such a polishing method, it is possible to more reliably and uniformly polish the warping shape of the wafer outer peripheral portion that was conventionally used by DSP, for example, and obtain a highly flat wafer system.

In addition, at this time, it is preferable to grind the wafer within a range of 20 to 50 mm in the radial direction only from the outer peripheral end of the wafer.

According to such a polishing method, only the warping shape of the outer peripheral portion of the wafer can be corrected more effectively, and it becomes possible to obtain a highly flat wafer system.

In addition, at this time, when the outer peripheral portion of the wafer is locally polished concentrically, it is preferable to control the polishing load by changing the relative height position of the local polishing pad of the polishing head supporting the wafer.

According to such a polishing method, it is possible to easily control the polishing load for local polishing of the outer peripheral portion of the wafer by bringing the wafer into contact with the local polishing pad.

In addition, at this time, the partially ground wafer is preferably a double-side ground wafer.

With such a polishing method, it is possible to locally correct the warpage of the outer peripheral portion of the wafer produced by DSP, to perform shape matching in CMP processing, and to reliably obtain a highly flat wafer system.

In addition, the present invention provides a wafer manufacturing method, which includes the step of partially grinding the outer peripheral portion of the wafer by the above-mentioned wafer grinding method of the present invention.

According to such a wafer manufacturing method, it becomes possible to manufacture a highly flat wafer system. [Compared with the effect of previous technology]

In the case of the grinding apparatus and wafer grinding method of the present invention, the outer peripheral portion of the wafer, such as DSP, is made into a warped shape and cannot be corrected after CMP processing, and the flatness becomes poor. The polishing device (CMP device) that functions as a part of the wafer (outer peripheral part of the wafer) can perform shape matching in CMP processing, and it is possible to obtain a highly flat wafer system.

The following describes the embodiments of the present invention with reference to the drawings, but the present invention is not limited thereto.

The flatness of the wafer in the polishing step is produced by the sum of the polishing process before CMP processing such as DSP processing and the removal amount of CMP processing.

Once the outer peripheral shape of the wafer after grinding before CMP processing changes greatly, there is a problem that the shape cannot be corrected to be flat during CMP processing, and a wafer with high flatness cannot be produced. In addition, the shape deterioration of the flatness is caused by the fact that there are many outer peripheral parts of the wafer.

DSP processing aims at a flat shape without sagging of the outer periphery, so that the outer peripheral part tends to become a warped shape. In order to prevent the outer periphery from sagging in the subsequent CMP processing, it becomes a somewhat warped shape. When the DSP shape varies into a large warped shape, it will cause flatness to deteriorate.

Then, the inventors of the present invention actively studied to solve such a problem. As a result, they found out that the deterioration of flatness can be suppressed by locally changing the shape of the wafer before CMP processing and matching the shape of the wafer before CMP processing with the shape of CMP, and completed the present invention.

First, an example of the polishing device of the present invention will be described. The grinding device of the present invention is a device in which a local grinding function is added to the grinding device.

Fig. 4 is a diagram showing an example of the mechanism of the polishing device of the present invention. The polishing device 11 of the present invention takes out the wafer from the wafer pod of the wafer loading device 13 , and sets the wafer on the loading table 16 for attaching the wafer to the grinding head. The grinding head is in a state where the back pad of the wafer adsorption surface is cleaned with pure water by a nylon brush, and waits for the loading platform 16 to come under the grinding head. After the loading table 16 stops under the grinding head, as shown in FIG. 5 , the grinding head 1 descends in order to attach the wafer W. The internal pressure P1 is a negative pressure to fix the wafer W to the back pad 2 .

In the grinding apparatus of the present invention, after the wafer W is supported on the grinding head 1, as shown in FIG. , is in contact with the wafer W, and the polishing head 1 is rotated while supplying the polishing slurry to concentrically polish a part of the wafer W.

At this time, it is better to control the machining peripheral speed only by the rotation of the grinding head.

In addition, at this time, the local polishing pad 18 is preferably in contact with the outer periphery of the wafer W at the central position of the local polishing pad 18 .

FIG. 2 shows an example different from FIG. 1 of the partial polishing pad in the polishing apparatus of the present invention. The polishing device of the present invention may also be one in which the local polishing pad 18 for polishing the part is disposed on the back pad cleaning table 8 of the loading/unloading mechanism 15 . At this time, the local grinding system is carried out in the following manner: after the wafer W is supported on the grinding head 1, the unit for scrubbing the grinding head 1 before the support of the wafer W is located at the lower part of the grinding head 1 again, and the grinding head 1 is lowered to be equipped on the back. The local polishing pad 18 of the pad cleaning table 8 , which is smaller than the wafer size, rises relatively toward the polishing head 1 , comes into contact with the wafer W, and rotates the polishing head 1 while supplying a polishing slurry.

6 and 8 are diagrams showing an example of cleaning the back pad of the polishing apparatus according to the present invention and an example of cleaning the back pad of the conventional polishing apparatus. 3 and 9 are diagrams showing an example of the back pad cleaning stand of the polishing apparatus of the present invention and an example of the back pad cleaning stand of the conventional polishing apparatus. In the past, as shown in Figure 8 and Figure 9, nylon wool 9' and fluid spray nozzle 10' were provided in the back pad cleaning table 8' to clean the grinding head 1'. On the other hand, as shown in Figure 3, in the back cushion cleaning platform 8 of the present invention, except nylon wool 9 and fluid spray nozzle 10, on the back cushion cleaning platform 8, be divided into four equal parts by nylon wool 9 One of the back pad cleaning benches 8 is provided with a local grinding pad 18. In addition, the partial polishing pad 18 of the back pad cleaning stand 8 of the present invention can move up and down separately from the back pad cleaning stand 8 . In addition, the polishing slurry is supplied to the surface of the wafer W from the same fluid spray nozzle 10 used for cleaning the polishing head 1 .

After the partial grinding of the wafer, the wafer is transported to the grinding processing table 19 for secondary grinding and finishing grinding. The wafer W is transported to the unloading table 17 and peeled off from the polishing head 1 by pure water jetting, and is transported by the unloading device 14. to the next step.

FIG. 7 is a diagram showing an example of polishing of the entire surface of a wafer by the polishing apparatus of the present invention. At the grinding table 19, the grinding cloth is attached to the fixed plate. Thereafter, as shown in FIG. 7 , the polishing slurry is supplied to the polishing cloth 6 attached to the platen 7 , and the polishing head 1 supporting the wafer W is slid on the polishing cloth 6 to perform polishing.

Next, the wafer polishing method of the present invention will be described using FIGS. 12 and 13 . FIG. 12 is a flowchart illustrating the operation of partial polishing in the wafer polishing method of the present invention. In addition, FIG. 13 is a diagram showing an example of a polishing flow by the wafer polishing method of the present invention.

In the wafer polishing method of the present invention, first, the wafer W is taken out from the pod ( FIG. 13(A) ), and the wafer W is set on the loading stage 16 ( FIG. 13(B) ).

Before the polishing head 1 supports the wafer W on the back pad 2 of the template 5 , the back pad 2 of the wafer suction surface is cleaned with pure water ( SC1 in FIG. 12 , (C) in FIG. 13 ). Here, as a method of cleaning the back pad, a case where the back pad cleaning table 8 is used in which the partial polishing pad 18 is disposed will be described as an example. Fig. 6 is a diagram showing an example of cleaning of the back pad of the polishing head of the present invention. After the grinding head 1 descends and reaches the cleaning position, the back pad cleaning table 8 with the nylon wool 9 and the fluid spray nozzle 10 will rise towards the grinding head 1 from the bottom of the grinding head 1 and approach. While pure water is sprayed toward the back pad 2 from the fluid spray nozzle 10 , nylon bristles (nylon brushes) 9 are brought into contact with the back pad 2 , and both the back pad cleaning table 8 and the polishing head 1 are rotated for cleaning. The rotation centers R1 and R2 of the grinding head 1 and the back pad cleaning table 8 are staggered, and the guide part 3 of the back pad is also brushed simultaneously. At this time, the local grinding pad 18 is on standby at a lower position than the nylon hair 9.

After cleaning the back pad 2 of the polishing head 1 with pure water, move the loading table 16 shown in FIG. Attached to the back pad 2 (SC2 of FIG. 12 , (E) of FIG. 13 ). Thereafter, the loading table 16 moves to the installation position of the next wafer ((F) of FIG. 13 ).

FIG. 5 is a diagram illustrating attachment of a wafer to a polishing head of the polishing apparatus of the present invention. After cleaning the back pad, the polishing head 1 stands by at a predetermined position, and then the wafer W placed on the PVA sponge 12 on the loading table 16 stands by directly below the polishing head 1 . Afterwards, the polishing head 1 is lowered to the position where the PVA sponge 12 is lightly pressed to support the wafer W on the wafer bag of the template 5, further, the pressure P1 of the polishing head 1 is negative pressure, and the back pad 2 is deformed to carry out wafer processing. support.

Different from the example of the grinding process by the conventional wafer grinding method shown in FIG. 14 , the wafer grinding method of the present invention includes partially grinding the outer periphery of the wafer W before the wafer is fully single-piece polished. A step of. In the partial polishing step, first, the back pad cleaning table 8 is raised to the side of the polishing head 1 ( FIG. 13(G) ). Further, the partial polishing pad 18 is relatively raised toward the polishing head 1 ((H) of FIG. 13 ), the partial polishing pad 18 is pushed against the wafer, and the polishing slurry is sprayed from the fluid ejection nozzle 10, so that the polishing head 1 is rotated to form a concentric circle. The outer peripheral portion of the wafer W is locally ground in a similar manner ( SC3 in FIG. 12 , (I) in FIG. 13 ).

In addition, at this time, the machining peripheral speed can be controlled only by the rotation of the polishing head.

In addition, at this time, local polishing may be performed in a positional relationship in which the center of the local polishing pad is in contact with the outer periphery of the wafer.

In addition, at this time, regardless of the diameter of the wafer, it is preferable to grind only within the range of 20 to 50 mm in the radial direction from the outer peripheral end of the wafer. In particular, in wafers with a large diameter of 300 mm or more, the flatness of this region becomes a problem.

In addition, at this time, the load can be adjusted by the height position of the local polishing pad.

After the wafer is partially polished, the polishing head 1 is rotated ( FIG. 13(J) ), and the polishing head 1 is lowered to be set on the polishing table 19 ( FIG. 13(K) ).

Attach the secondary grinding cloth or modified grinding cloth to the fixed plate 7, and apply the load with the pressure P1 (internal pressure) and pressure P2 (external pressure), so that the grinding head 1 and the fixed plate 7 are rotated to fully grind the partially ground wafer (SC4 in FIG. 12 , (L) in FIG. 13 ).

The polishing head 1 performs polishing by combining the pressure P1 for operating the wafer support position and the pressure P2 for operating the guide portion 3 of the template. When the back pad 2 of the template 5 supports the wafer W, the wafer W is absorbed by the surface tension of the pure water by making the back pad surface contain pure water, and the deformation of the back pad 2 by making the pressure P1 a negative pressure The wafer adsorption was performed by both.

After the entire surface of the wafer W is polished, the polishing head 1 rises and leaves the polishing table 19 ( FIG. 13(M) ). The steps of (J) to (M) in FIG. 13 can be repeated several times like the steps of (N) to (U) in FIG. 13 .

In addition, the wafer to be partially ground at this time is a double-side ground wafer, and the outer peripheral shape of the DSP wafer can be partially corrected by the CMP apparatus before the CMP process.

FIG. 10 is a diagram showing an example of a polishing flow using a polishing apparatus of the present invention, and FIG. 11 is a diagram showing an example of a polishing flow using a conventional polishing apparatus. Although shown in the example of the grinding process of the grinding device in the past using the grinding device in the past, after carrying out DSP S1 ', carry out secondary grinding S3 ', secondary grinding S4 ', but in the grinding method of the present invention, can be as shown in Figure 10 Generally, after DSP S1, before CMP, local polishing S2 of the outer periphery of the wafer is performed, transported to the polishing table 19, secondary polishing S3, secondary polishing S4 are performed, and finally touch-up polishing S5 is performed.

After the tray of the unloading table 17 moves to the loading/unloading position ((V) in FIG. 13 ), the fully polished wafer W is transported to the unloading table 17 , and the polishing head 1 is lowered ((W) in FIG. 13 ). The circle W is peeled off from the polishing head 1 by pure water jetting ((X) of FIG. 13 ), and is conveyed to the next step (cleaning of the subsequent step) ((Y) of FIG. 13 ).

In this way, wafers are produced. According to such a wafer manufacturing method of the present invention, a highly flat wafer can be manufactured. [Example]

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated concretely, this invention is not limited to these.

(Example 1-5) The diameter of the local grinding pad is under five levels of 138mm (embodiment 1), 98mm (embodiment 2), 50.8mm (embodiment 3), 38mm (embodiment 4) and 18mm (embodiment 5). The wafer after polishing (DSP) is partially polished, and then the wafer is fully polished on one side (CMP) (secondary polishing and touch-up polishing), and ESFQR (max), which is one of the evaluation indicators for flatness at the edge, is compared. The difference before and after the partial grinding process. In addition, the local polishing process is performed by bringing the outer periphery of the wafer into contact with the central position of the local polishing pad.

The processing conditions of partial grinding are as follows. [Grinding Processing Conditions] Device: Single-sided grinding machine made by Fujikoshi Machinery Wafer: Diameter 300mm P ^- product <100> Silicon wafer Abrasive cloth: Abrasive cloth and non-woven cloth Abrasive: Abrasive slurry KOH base colloidal silica

The processing conditions for full grinding are as follows. [Grinding Processing Conditions] Device: Single-side grinding machine made by Fujikoshi Machinery Wafer: Diameter 300mm P ^- product <100> Silicon wafer grinding cloth: grinding cloth non-woven cloth (secondary grinding) and velvet cloth (modifying grinding) two kinds of abrasives : Slurry KOH-based colloidal silica and N ₄ OH-based colloidal silica

For the flatness measurement of the wafer, a flatness measuring machine WaferSight 2 manufactured by KLA-Tencor was used. Excluding the peripheral area (E.E.) is carried out in 1mm. ΔESFQR(max) was calculated from the measured flatness of the wafer.

Table 1 shows the relationship between the size (diameter) of the local polishing pad and the contact area of the local polishing pad on the wafer (pad contact area on the wafer) in each embodiment.

【Table 1】

The results of ΔESFQR(max) in Examples 1-5 are shown in FIG. 15 . In Examples 1-5, ΔESFQR(max) showed a negative value or a small positive value. In Examples 1-4, the value of ΔESFQR(max) after the wafer is fully polished is reduced by partial grinding, so that the flatness of the wafer is improved. In addition, in Example 5, ΔESFQR(max) was lowered to reduce flatness deterioration due to the inability to perform shape matching between double-side grinding and single-side grinding.

Once the size (diameter) of the local polishing pad becomes smaller than 98mm, the correction effect of the peripheral warping will become greater. In addition, once it becomes more than 18mm, the correction effect will become more appropriate, so the local correction range is from the outer peripheral end of the wafer The range from 100mm is better.

(Comparative Example 1, Example 6) Next, ESFQR (max) in the case of performing CMP processing (comparative example 1) without partial polishing in the same manner as in the conventional method and in the state of partial polishing by the partial polishing pad of the present invention with a diameter of 50.8mm Wafer shape diagrams in the case of performing up to CMP processing (Example 6) were compared.

In Example 6, partial grinding and full grinding were carried out under the same conditions as in Examples 1-5. In addition, in Comparative Example 1, the overall polishing was performed under the same conditions as in Examples 1-5.

In addition, for the flatness measurement of the wafer, a flatness measuring machine WaferSight 2 manufactured by KLA-Tencor was used. Excluding the peripheral area (E.E.) is carried out in 1mm.

16 shows the wafer shape line diagram after DSP processing, the wafer shape line diagram after partial grinding, the wafer shape line diagram after CMP processing, and the grinding removal amount line by partial grinding in Example 6. Figure and the grinding removal amount line diagram processed by CMP.

FIG. 17 shows a wafer shape diagram after DSP processing, a wafer shape diagram after CMP processing, and a grinding removal amount diagram by CMP processing in Comparative Example 1. FIG.

Once the changes in wafer shape in each processing step are compared between the case with local grinding (Example 6) and the case without (Comparative Example 1), it can be known that the raw material before CMP processing can be reduced by local grinding. The generated warping is eliminated, and the shape after CMP processing can be flattened by partial grinding.

(Comparative Example 2, Example 7) Furthermore, ESFQR (max) when performing CMP processing (comparative example 2) without partial polishing in the same manner as in the conventional method and in the state of partial polishing by a partial polishing pad with a diameter of 50.8 mm of the present invention ESFQR (max) up to CMP processing (Example 7) was performed and compared.

For the flatness measurement of the wafer, a flatness measuring machine WaferSight 2 manufactured by KLA-Tencor was used. Excluding the peripheral area (E.E.) is carried out in 1mm.

Fig. 18 shows the ESFQR (max) when performing CMP processing (Comparative Example 2) in the same state without partial polishing as in the conventional method, and the state of partial polishing by the partial polishing pad with a diameter of 50.8mm of the present invention. Below is a graph comparing ESFQR (max) up to CMP processing (Example 7).

As shown in FIG. 18 , compared with the conventional polishing method (Comparative Example 2), the correction method (Example 7) by local polishing according to the present invention showed a good result with a small value of flatness.

As mentioned above, using the polishing apparatus and polishing method of the present invention, it is possible to improve the unevenness of wafer flatness by performing local polishing on a local polishing pad before CMP processing.

In addition, the present invention is not limited to the above-mentioned implementation forms. The above-mentioned implementation forms are for illustration, and those who have the technical idea and substantially the same structure as recorded in the patent application scope of the present invention and produce the same effect, no matter what they are, are included in the technical scope of the present invention.

1‧‧‧Grinding head 1’‧‧‧grinding head 2‧‧‧Back pad 3‧‧‧guidance department 4‧‧‧ceramic ring 5‧‧‧template 6‧‧‧Abrasive cloth 7‧‧‧Fixed order 8‧‧‧Back pad washing table 8’‧‧‧Back pad washing table 9‧‧‧Nylon wool 9’‧‧‧Nylon wool 10‧‧‧fluid spray nozzle 10’‧‧‧fluid spray nozzle 11‧‧‧Grinding device 12‧‧‧PVA sponge 13‧‧‧Loading device 14‧‧‧Uninstalling the device 15‧‧‧Loading/unloading mechanism 16‧‧‧Loading platform 17‧‧‧Unloading station 18‧‧‧Grinding pad 19‧‧‧Grinding table CMP‧‧‧Single side grinding DSP‧‧‧Double side grinding P1‧‧‧pressure P2‧‧‧pressure R1‧‧‧rotation center R2‧‧‧rotation center S1‧‧‧DSP processing S1’‧‧‧DSP processing S2‧‧‧partial grinding S3‧‧‧Secondary Grinding S3’‧‧‧secondary grinding S4‧‧‧Secondary Grinding S4’‧‧‧Secondary Grinding S5‧‧‧Modification Grinding S5’‧‧‧Modification and Grinding SC1‧‧‧step SC2‧‧‧Steps SC3‧‧‧step SC4‧‧‧step W‧‧‧Wafer

FIG. 1 is a diagram showing an example of a partial polishing pad in the polishing apparatus of the present invention. Fig. 2 is a view showing an example of a partial polishing pad in the polishing apparatus of the present invention different from Fig. 1 . Fig. 3 is a diagram showing an example of a back pad cleaning stand of the polishing apparatus of the present invention. Fig. 4 is a diagram showing an example of the mechanism of the polishing device of the present invention. FIG. 5 is a diagram illustrating attachment of a wafer to a polishing head of the polishing apparatus of the present invention. Fig. 6 is a diagram showing an example of cleaning of the back pad of the polishing device of the present invention. FIG. 7 is a diagram showing an example of polishing of the entire surface of a wafer by the polishing apparatus of the present invention. FIG. 8 is a diagram showing an example of cleaning of a back pad of a conventional polishing device. Fig. 9 is a diagram showing an example of a back pad cleaning stand of a conventional polishing device. Fig. 10 is a diagram showing an example of a polishing flow using the polishing apparatus of the present invention. FIG. 11 is a diagram showing an example of a polishing flow using a conventional polishing apparatus. FIG. 12 is a flowchart illustrating the operation of partial polishing in the wafer polishing method of the present invention. FIG. 13 is a diagram showing an example of a polishing flow by the wafer polishing method of the present invention. FIG. 14 is a diagram showing an example of a polishing flow by a conventional wafer polishing method. FIG. 15 is a graph showing the results of ΔESFQR(max) in Examples 1-5. 16 is a line diagram showing the wafer shape after DSP processing, a wafer shape line diagram after partial polishing, a wafer shape line diagram after CMP processing, and a partial wafer shape diagram by the polishing method of the present invention (Example 6). Grinding removal line graph of grinding process and grinding removal amount line graph of processing by CMP. 17 is a graph showing the wafer shape after DSP processing, the wafer shape after CMP processing, and the grinding removal amount by CMP processing by a conventional polishing method (Comparative Example 1). 18 is a graph comparing ESFQR (max) by the conventional polishing method (Comparative Example 2) and ESFQR (max) by the polishing method of the present invention (Example 7).

none

1‧‧‧Grinding head

2‧‧‧Back pad

3‧‧‧guidance department

4‧‧‧ceramic ring

5‧‧‧template

18‧‧‧Partial grinding pad

R1‧‧‧rotation center

W‧‧‧Wafer

Claims (13)

A grinding device, comprising: a grinding head, which is used to support a wafer; a fixed disk, which is attached with a grinding cloth for grinding the wafer; a loading table, which is used to install the wafer to the grinding head ; an unloading station for peeling off the wafer from the grinding head, the grinding device is used to grind the wafer supported by the grinding head, wherein the grinding device further includes a movable up and down smaller than the wafer The partial polishing pad is raised relatively toward the polishing head so that the wafer supported by the polishing head comes into contact with the partial polishing pad, and the polishing head supporting the wafer is rotated to form a partial polishing pad. Grinding the outer peripheral portion of the wafer concentrically, the grinding device includes a back pad cleaning table that can move up and down for cleaning the grinding head, the local polishing pad is configured on the back pad cleaning table, And the back pad cleaning table and the local polishing pad can move up and down respectively. The polishing apparatus according to claim 1, wherein the partial polishing pad is ground by contacting the outer periphery of the wafer with the center of the partial polishing pad. A wafer grinding method is a wafer grinding method using the grinding device described in claim 1, wherein before performing comprehensive single-side grinding of the wafer, the local grinding pad is relatively raised toward the grinding head While the wafer supported by the polishing head is brought into contact with the partial polishing pad, the polishing head supporting the wafer is rotated to locally polish the outer periphery of the wafer concentrically. The wafer polishing method according to claim 3, wherein the partial polishing pad is ground by contacting the outer periphery of the wafer with the center of the partial polishing pad. The wafer grinding method according to claim 3, wherein the wafer is ground within a radial direction of 20 to 50 mm only from the outer peripheral end of the wafer. The wafer grinding method according to claim 4, wherein the wafer is ground within a radius of 20 to 50 mm only from the outer peripheral end of the wafer. The wafer grinding method as described in claim 3, wherein when the peripheral portion of the wafer is locally ground concentrically, the relative height position of the local grinding pad of the grinding head supporting the wafer is controlled by changing Grinding load. The wafer grinding method as described in claim 4, wherein when the peripheral part of the wafer is locally ground concentrically, the relative height position of the local grinding pad of the grinding head supporting the wafer is controlled by changing Grinding load. The wafer grinding method as described in claim 5, wherein when the peripheral portion of the wafer is locally ground concentrically, the relative height position of the local grinding pad of the grinding head supporting the wafer is controlled by changing Grinding load. The wafer grinding method as described in claim 6, wherein when the peripheral portion of the wafer is locally ground concentrically, the relative height position of the local grinding pad of the grinding head supporting the wafer is controlled by changing Grinding load. The wafer grinding method according to any one of claims 3 to 10, wherein the partially ground wafer is a double-side ground wafer. A method for manufacturing a wafer, comprising the step of partially grinding the outer periphery of the wafer by the method for grinding a wafer according to any one of claims 3 to 10. A method of manufacturing a wafer, comprising the step of partially grinding the outer periphery of the wafer by the wafer grinding method described in claim 11.

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