TW201945121A - Polishing device, wafer polishing method, and wafer manufacturing method - Google Patents

Abstract

The present invention is a polishing device that is provided with a polishing head, a surface plate to which a polishing cloth is affixed, a loading stage for attaching a wafer to the polishing head, and an unloading stage for detaching the wafer from the polishing head, and polishes the wafer held by the polishing head. The polishing device is characterized by being further provided with a local polishing pad smaller than the wafer and movable up and down, and being able to locally polish a wafer outer peripheral portion concentrically by rotating the polishing head that holds the wafer while bringing the wafer held by the polishing head and the local polishing pad into contact with each other by relatively elevating the local polishing pad toward the polishing head. Consequently, provided are a polishing device and a wafer polishing method, with which a wafer shape after CMP processing can be planarized by further improving shape matching between polishing processing, such as DSP processing, before the CMP processing and the CMP processing as compared to conventional ones.

Description

Polishing device, wafer polishing method, and wafer manufacturing method

The present invention relates to a polishing apparatus, a method for polishing a wafer, and a method for manufacturing a wafer.

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

FIG. 11 is a diagram showing an example of a conventional polishing process of a wafer. After the wafer DSP is processed (S1 '), a secondary polishing process (S3') is performed, and finally a polishing process (S5 ') is performed. The secondary grinding process may be repeated twice or more as 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 unevenness of the wafer.

CMP processing is performed on the wafer after DSP processing. In DSP processing, the outer shape of the wafer is produced with the aim of raising the shape. In the subsequent CMP processing, the overall shape is aimed at conforming to the front shape, but in order to prevent the outermost peripheral portion of the wafer from sagging, it is set to have a number of raised shapes. Therefore, the shape matching in DSP and CMP may not be performed smoothly, and the shape of DSP may be deteriorated during CMP processing.
[Previous Technical Literature]
[Patent Literature]

[Patent Document 1] JP 2010/023829 [Patent Document 2] JP 2012-35393 [Patent Document 3] JP 2013/001719

[Problems to be solved by the invention]
As described above, in the past, the outer peripheral shape of the wafer by polishing processing such as double-side polishing (DSP) processing has sometimes become a raised shape. Since the outermost peripheral portion of the wafer is set to a raised shape during CMP processing, Polishing processing before CMP processing such as DSP processing and shape matching during CMP processing may not be performed smoothly, and the shape of polishing processing by DSP processing or the like may be deteriorated during CMP processing. In order to improve the quality of the wafer after the CMP process, it is necessary to match the shape of the polishing process before the CMP process such as the DSP process to the shape during the CMP process.

In view of the above problems, the present invention provides a polishing apparatus and a wafer polishing method, which can improve the shape matching between the polishing processing before CMP processing such as DSP processing and the CMP processing as compared with the past. The wafer shape is flattened.
[Technical means to solve problems]

In order to solve the above-mentioned problem, the present invention provides a polishing device including a polishing head for supporting a wafer; a certain disk attached with a polishing cloth for polishing the wafer; a loading table for The grinding head mounts the wafer; an unloading table is used to peel the wafer from the grinding head, and the grinding device is used for grinding the wafer supported by the grinding head, wherein the grinding device further includes a vertical movement and The wafer is a small local polishing pad. While the local polishing pad is relatively raised toward the polishing head to contact the wafer supported by the polishing head with the local polishing pad, the wafer supporting the wafer is also supported. The polishing head is rotated to locally polish the outer peripheral portion of the wafer in a concentric circle shape.

In the case of such a polishing device, even if the wafer outer peripheral portion is formed in a raised shape, a polishing device (CMP device) having a function of correcting a part of the wafer (the outer peripheral portion of the wafer) can be used for CMP processing. Shape matching makes it possible to obtain a highly flat wafer system.

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

With such a polishing device, it is possible to more accurately and uniformly polish the raised shape of the wafer outer peripheral portion.

In addition, at this time, the polishing device includes a back pad cleaning table for cleaning the polishing head, which can be moved up and down, the local polishing pad is disposed on the back pad cleaning table, and the back pad cleaning table and the It is preferable that the local polishing pads can be moved up and down separately.

In the case of such a polishing apparatus, a partial polishing pad is disposed on a back pad cleaning stage of the polishing apparatus, and the warped shape of the wafer peripheral portion can be easily corrected, and a shape matching system in CMP processing becomes possible.

In addition, the present invention provides a wafer polishing method, which is a wafer polishing method using the polishing apparatus of the present invention, in which the local polishing pad is opposed to the polishing head before full-sided single-side polishing of the wafer is performed. When the wafer is raised to contact the wafer supported by the polishing head and the local polishing pad, the polishing head supporting the wafer is rotated to locally polish the outer peripheral portion of the wafer in a concentric circle.

In the case of such a polishing method, in the past, for example, an outer peripheral portion of a wafer made of a DSP was formed into a warped shape, which could not be corrected after CMP processing, and the flatness was deteriorated. The peripheral polishing) function polishing device (CMP device) performs local polishing to perform shape matching during CMP processing, and it is possible to obtain a highly flat wafer system.

In addition, at this time, the local polishing pad is preferably polished by contacting the outer periphery of the wafer with the center position of the local polishing pad.

With such a polishing method, it is possible to more reliably and uniformly polish a wafer wafer peripheral shape in the past, for example, to obtain a highly flat wafer system.

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

With such a polishing method, it is possible to more effectively correct only the warped shape of the wafer outer peripheral portion, and it is possible to obtain a highly flat wafer system.

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

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

In addition, the wafer that is locally polished at this time is preferably a wafer that has been double-ground polished.

In such a polishing method, the warping of the outer peripheral portion of the wafer produced by the DSP is partially corrected to enable shape matching during CMP processing, and it is possible to reliably obtain a highly flat wafer system.

In addition, the present invention provides a method for manufacturing a wafer, which includes a step of locally polishing the outer peripheral portion of the wafer by the above-described method for polishing a wafer.

With such a wafer manufacturing method, it is possible to manufacture a highly flat wafer system.
[Contrast with the effect of the prior art]

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

In the following, the present invention is described with reference to the drawings and the embodiments, 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 amount before the CMP processing such as DSP processing and the CMP processing.

If the shape of the wafer periphery after the polishing process before the CMP process is greatly changed, there is a problem that the shape cannot be corrected to be flat during the CMP process and a wafer having a high flatness cannot be produced. In addition, the deterioration in the shape of the flatness is caused by the large number of wafer peripheral portions.

The purpose of the DSP processing system is to achieve a flat shape without sagging the outer periphery, so that the outer periphery easily becomes a raised shape. In order to prevent the outer periphery from sagging during subsequent CMP processing, the shape becomes slightly raised. When the DSP shape has a large raised shape, the flatness is deteriorated.

Then, the present inventors have actively studied in order to solve such problems. As a result, it was found that the shape of the wafer was locally changed before the CMP process, and the shape of the wafer before the CMP process was matched with the shape of the CMP, thereby suppressing the deterioration of the flatness, and completed the present invention.

First, an example of the polishing apparatus of the present invention will be described. The polishing apparatus of the present invention is a device that adds a local polishing function to the polishing apparatus.

FIG. 4 is a diagram showing an example of a mechanism of the polishing apparatus of the present invention. The polishing apparatus 11 of the present invention is to take out a wafer from a wafer box of a wafer loading apparatus 13 and set the wafer on a loading table 16 for attaching the wafer to a polishing head. The polishing head is in a state in which the back pad of the wafer adsorption surface is washed with pure water by a nylon brush, and waits for the loading table 16 to come under the polishing head. After the loading table 16 stops under the polishing head, as shown in FIG. 5, the polishing head 1 is lowered to attach the wafer W. After the wafer W enters the pocket hole of the template 5 under the ceramic ring 4, the polishing head 1 The internal pressure P1 is a negative pressure to fix the wafer W to the back pad 2.

After the wafer W is supported by the polishing head 1, as shown in FIG. 1, the polishing device of the present invention is lowered, and the local polishing pad 18, which is moved up and down and is smaller than the wafer, is relatively raised toward the polishing head 1. The wafer W is in contact with the wafer W, and the polishing head 1 is rotated while supplying the polishing slurry, so that a part of the wafer W can be polished concentrically.

In this case, it is preferable that the processing peripheral speed is controlled only by the rotation of the polishing head.

In addition, at this time, it is preferable that the local polishing pad 18 is in contact with the center position of the local polishing pad 18 and the position of the outer periphery of the wafer W.

FIG. 2 shows an example of a partial polishing pad in the polishing apparatus of the present invention different from that of FIG. 1. The polishing apparatus of the present invention may also be a product in which the local polishing pad 18 to be polished is disposed on the back pad washing table 8 of the loading / unloading mechanism 15. At this time, the local polishing is performed in the following manner: After the wafer W is supported on the polishing head 1, the unit for brushing the polishing head 1 before the wafer W is supported is located at the lower part of the polishing head 1 again. The local polishing pad 18 having a smaller wafer size than that of the pad cleaning table 8 rises relatively toward the polishing head 1 and comes into contact with the wafer W to rotate the polishing head 1 while supplying the polishing slurry.

6 and 8 are diagrams showing an example of cleaning a back pad of the polishing apparatus of the present invention and an example of cleaning a back pad of a conventional polishing apparatus. 3 and 9 are diagrams showing an example of a back pad cleaning table of a polishing apparatus of the present invention and an example of a back pad cleaning table of a conventional polishing apparatus. In the past, as shown in Figs. 8 and 9, the back pad cleaning table 8 'was provided with nylon wool 9' and a fluid spray nozzle 10 'to clean the polishing head 1'. On the other hand, as shown in FIG. 3, in the back pad washing table 8 of the present invention, in addition to the nylon wool 9 and the fluid spray nozzle 10, the back pad washing table 8 is divided into four equal parts by the nylon wool 9 A local polishing pad 18 is provided at one position of the back pad cleaning table 8 of the back pad cleaning station 8. In addition, the partial polishing pad 18 of the back pad washing table 8 of the present invention can be moved up and down separately from the back pad washing table 8. The polishing slurry is supplied to the surface of the wafer W from a fluid spray nozzle 10 which is common to the polishing head 1 when the polishing head 1 is cleaned.

After the wafer is locally polished, the wafer is transferred to the polishing processing table 19 for secondary polishing and modification polishing. The wafer W is transferred to the unloading table 17 and peeled from the polishing head 1 by spraying with pure water, and is transferred by the unloading device 14 Go to the next step.

FIG. 7 is a diagram showing an example of the entire polishing process of the wafer by the polishing apparatus of the present invention. The polishing cloth is attached to the platen at the polishing table 19. Thereafter, as shown in FIG. 7, a 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, a wafer polishing method of the present invention will be described with reference to FIGS. 12 and 13. FIG. 12 is a flowchart illustrating the operation of the local polishing process in the method of polishing a wafer according to the present invention. In addition, FIG. 13 is a diagram showing an example of a polishing flow by the polishing method of a wafer of the present invention.

In the wafer polishing method of the present invention, first, the wafer W is taken out from the wafer box (FIG. 13 (A)), and the wafer W is set on the loading table 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 on the wafer suction surface is washed with pure water (SC1 in FIG. 12 and (C) in FIG. 13). Here, as a method of cleaning the back pad, a case where the back pad washing table 8 is used with the local polishing pad 18 disposed thereon will be described as an example. FIG. 6 is a view showing an example of cleaning the back pad of the polishing head of the present invention. After the polishing head 1 is lowered to reach the cleaning position, the back pad cleaning table 8 with the nylon wool 9 and the fluid spray nozzle 10 will rise from the lower side of the polishing head 1 toward the polishing head 1 and approach. While spraying pure water toward the back pad 2 from the fluid spray nozzle 10, the nylon hairs (nylon brushes) 9 are brought into contact with the back pad 2, and both the back pad washing table 8 and the polishing head 1 are rotated and washed. The rotation centers R1 and R2 of the polishing head 1 and the back pad cleaning table 8 are staggered, and the guide part 3 of the back pad is also brushed at the same time. At this time, the local polishing pad 18 is on standby at a position lower than the nylon wool 9.

After the back pad 2 of the polishing head 1 is washed with pure water, it is moved to the loading table 16 shown in FIG. 4 to move directly below the polishing head 1 (FIG. 13 (D)). The polishing head 1 is lowered and the wafer W It is attached to the back pad 2 (SC2 of FIG. 12, (E) of FIG. 13). After that, the loading stage 16 moves and moves to the installation position of the next wafer (FIG. 13 (F)).

FIG. 5 is a diagram illustrating a wafer attachment to a polishing head of a polishing apparatus of the present invention. The polishing head 1 that has finished cleaning the back pad is on standby at a predetermined position, and the wafer W on the PVA sponge 12 disposed on the loading table 16 is on standby immediately below the polishing head 1. Thereafter, the polishing head 1 is lowered to a position where the PVA sponge 12 is lightly pressed to support the wafer W in the wafer bag of the template 5, and further, the pressure P1 of the polishing head 1 is made a negative pressure, and the back pad 2 is deformed to perform the wafer. Support.

Different from the example of the polishing process by the conventional wafer polishing method shown in FIG. 14, the wafer polishing method of the present invention includes partially polishing the outer peripheral portion of the wafer W before the single wafer polishing of the wafer is completed. A step of. In the local polishing step, first, the back pad washing table 8 is raised to the polishing head 1 side ((G) of FIG. 13). Further, the local polishing pad 18 relatively rises toward the polishing head 1 (FIG. 13 (H)), pushes the local polishing pad 18 against the wafer, sprays the polishing slurry from the fluid ejection nozzle 10, and rotates the polishing head 1 into a concentric circle. The outer peripheral portion of the wafer W is partially polished (SC3 in FIG. 12 and (I) in FIG. 13).

In this case, the processing peripheral speed can be controlled only by the rotation of the polishing head.

In addition, at this time, the local polishing may be performed under the positional relationship between the center portion of the local polishing pad and the outer peripheral portion of the wafer.

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

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

After the wafer is locally polished, the polishing head 1 is rotated ((J) in FIG. 13), and the polishing head 1 is lowered and set on the polishing processing table 19 ((K) in FIG. 13).

Place the secondary polishing cloth or modified polishing cloth on the fixing plate 7 and apply a load with pressure P1 (internal pressure) and pressure P2 (external pressure) to rotate the polishing head 1 and the fixing plate 7 to fully polish the partially polished wafer. (SC4 in FIG. 12 and (L) in FIG. 13).

The polishing head 1 performs a polishing process by combining a pressure P1 for operating a wafer support position and a pressure P2 for operating a guide portion 3 of a template. When the wafer W is supported by the back pad 2 of the template 5, the back pad 2 contains pure water and is adsorbed by the wafer with the surface tension of pure water, and the pressure P1 is negative and the back pad 2 is deformed. The wafer adsorption was performed by both.

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

In addition, the wafer to be locally polished at this time is a wafer subjected to double-side polishing processing, and the peripheral shape of the wafer of the DSP can be partially corrected by the CMP device before the CMP processing.

FIG. 10 is a diagram showing an example of a polishing flow using a polishing device of the present invention, and FIG. 11 is a diagram showing an example of a polishing flow using a conventional polishing device. Although shown in the example of the polishing process using the conventional polishing device in FIG. 11, after performing DSP S1 ′, secondary polishing S3 ′ and secondary polishing S4 ′ are performed. However, in the polishing method of the present invention, FIG. 10 can be used. Generally, after the DSP S1 is performed, before the CMP, the local polishing S2 of the wafer peripheral portion is carried out, and the wafer S1 is transported to the polishing processing table 19 to perform the secondary polishing S3, the secondary polishing S4, and finally the modified polishing S5.

After the tray of the unloading stage 17 is moved to the loading / unloading position ((V) of FIG. 13), the wafer W that has been subjected to the overall polishing process is transferred to the unloading stage 17, and the polishing head 1 is lowered (FIG. 13 (W)). The circle W is peeled from the polishing head 1 by spraying pure water ((X) in FIG. 13), and is transported to the next step (cleaning in the subsequent step) ((Y) in FIG. 13).

In this way, a wafer is manufactured. According to the method for manufacturing a wafer of the present invention, a highly flat wafer can be manufactured.
[Example]

Examples and comparative examples are given below to specifically explain the present invention, but the present invention is not limited to these.

(Example 1-5)
The diameter of the partial abrasive pad was double-sided at five levels of 138mm (Example 1), 98mm (Example 2), 50.8mm (Example 3), 38mm (Example 4), and 18mm (Example 5). After the wafer is polished (DSP), the wafer is partially polished, and then the wafer is subjected to comprehensive single-side polishing (CMP) (secondary polishing and modified polishing). ESFQR (max), one of the flatness evaluation indexes of the edge portion, is compared. The difference before and after local grinding.
The local polishing process is performed by bringing the outer periphery of the wafer into contact with the center position of the local polishing pad.

The processing conditions for local polishing are as follows.
[Polishing conditions]
Device: Fujitsu single-side polishing machine Wafer: 300mm diameter P ^- product <100> Silicon wafer polishing cloth: abrasive cloth non-woven abrasive abrasive: polishing slurry KOH-based colloidal silicon dioxide

The processing conditions of the full grinding are as follows.
[Polishing conditions]
Device: Fujitsu mechanical single-side lapping machine Wafer: 300mm diameter P ^- product <100> Silicon wafer abrasive cloth: abrasive cloth non-woven fabric (secondary abrasive) and flannel (modified abrasive) two abrasives: abrasive slurry KOH substrate Colloidal silica and N ₄ OH based colloidal silica

Wafer flatness was measured using WaferSight 2 made by KLA-Tencor. The outer periphery exclusion range (E﹒E﹒) is performed at 1 mm. 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 range of the local polishing pad on the wafer (pad contact range on the wafer) in each example.

【Table 1】

The results of ΔESFQR (max) of Examples 1-5 are shown in FIG. 15. In Examples 1-5, ΔESFQR (max) is shown as a negative value or a small positive value. In Example 1-4, the value of ΔESFQR (max) after the wafer was completely polished was reduced by local polishing, so that the flatness of the wafer was improved. In addition, in Example 5, ΔESFQR (max) was reduced, and the flatness was deteriorated due to the inability to match the shapes of the double-side polishing process and the single-side polishing process.

Once the size (diameter) of the local polishing pad becomes less than 98mm, the effect of correction of the peripheral lift will become larger. In addition, once it is 18mm or more, the correction effect will become more appropriate. Therefore, the local correction range is from the outer peripheral end of the wafer. A range of 100 mm is preferred.

(Comparative Example 1, Example 6)
Next, the ESFQR (max) in the case of performing CMP processing (Comparative Example 1) without local polishing in the same manner as in the conventional method, and in a state of local polishing by a local polishing pad with a diameter of 50.8 mm according to the present invention The wafer shape line drawing in the case of performing the CMP process (Example 6) is compared.

In Example 6, local polishing and full polishing were performed under the same conditions as in Examples 1-5. In Comparative Example 1, the full-polishing was performed under the same conditions as in Examples 1-5.

In addition, wafer flatness measurement was performed using a flatness measuring machine WaferSight 2 manufactured by KLA-Tencor. The outer periphery exclusion range (E﹒E﹒) is performed at 1 mm.

FIG. 16 shows a wafer shape line diagram after the DSP processing in Example 6, a wafer shape line diagram after the local grinding process, a wafer shape line diagram after the CMP process, and a grinding and polishing amount line by the local grinding process. Figures and line graphs of polishing and removal by CMP processing.

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

Once the local shape polishing (Example 6) and the absence (Comparative Example 1) of the wafer shape are compared in each processing step, it can be seen that the local polishing is used to make the raw material before CMP processing. The generated warping is eliminated, and the shape after CMP processing can be flattened by local polishing.

(Comparative Example 2, Example 7)
Further, ESFQR (max) when CMP processing (Comparative Example 2) was performed without local polishing in the same manner as in the conventional method, and in a state of local polishing by a local polishing pad with a diameter of 50.8 mm of the present invention ESFQR (max) at the time of CMP processing (Example 7) was compared.

Wafer flatness was measured using WaferSight 2 made by KLA-Tencor. The outer periphery exclusion range (E﹒E﹒) is performed at 1 mm.

FIG. 18 shows the state of ESFQR (max) when CMP processing (Comparative Example 2) was performed without local polishing in the same manner as in the conventional method, and the state was locally polished by a local polishing pad with a diameter of 50.8 mm according to the present invention. The figure comparing ESFQR (max) at the time of CMP processing (Example 7).

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

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

In addition, the present invention is not limited to the above-mentioned embodiments. The above implementation mode is an example, and anyone who has the same technical idea and substantially the same structure as those described in the patent application scope of the present invention to produce the same effect is included in the technical scope of the present invention no matter what.

1‧‧‧ grinding head

1’‧‧‧ grinding head

2‧‧‧Back pad

3‧‧‧Guide

4‧‧‧ceramic ring

5‧‧‧ template

6‧‧‧ abrasive cloth

7‧‧‧ fixed

8‧‧‧Back pad washing table

8’‧‧‧Back pad washing station

9‧‧‧ nylon wool

9’‧‧‧ nylon wool

10‧‧‧ fluid spray nozzle

10’‧‧‧ fluid spray nozzle

11‧‧‧Grinding device

12‧‧‧PVA sponge

13‧‧‧ Loading device

14‧‧‧ unloading device

15‧‧‧ Loading / unloading mechanism

16‧‧‧ Loading platform

17‧‧‧ unloading station

18‧‧‧ Abrasive pad

19‧‧‧Grinding processing table

CMP‧‧‧Single-side grinding

DSP‧‧‧ Double-sided 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‧‧‧Modified grinding

S5’‧‧‧Modified grinding

SC1‧‧‧step

SC2‧‧‧step

SC3‧‧‧step

SC4‧‧‧step

W‧‧‧ Wafer

FIG. 1 is a view showing an example of a local polishing pad in a 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 that of FIG.

FIG. 3 is a view showing an example of a back pad cleaning table of the polishing apparatus of the present invention.

FIG. 4 is a diagram showing an example of a mechanism of the polishing apparatus of the present invention.

FIG. 5 is a diagram illustrating a wafer attachment to a polishing head of a polishing apparatus of the present invention.

FIG. 6 is a view showing an example of cleaning the back pad of the polishing apparatus of the present invention.

FIG. 7 is a diagram showing an example of the entire polishing process of the wafer by the polishing apparatus of the present invention.

FIG. 8 is a diagram showing an example of cleaning a back pad of a conventional polishing apparatus.

FIG. 9 is a view showing an example of a back pad cleaning table of a conventional polishing apparatus.

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 process using a conventional polishing apparatus.

FIG. 12 is a flowchart illustrating the operation of the local polishing process in the method of polishing a wafer according to the present invention.

FIG. 13 is a diagram showing an example of a polishing flow by a method of polishing a wafer according to the present invention.

FIG. 14 is a diagram showing an example of a polishing process by a conventional wafer polishing method.

FIG. 15 is a graph showing the results of ΔESFQR (max) in Examples 1-5.

FIG. 16 shows a wafer shape line diagram after DSP processing by the polishing method (Example 6) of the present invention, a wafer shape line diagram after local polishing processing, a wafer shape line diagram after CMP processing, and Line diagram of the grinding and polishing amount of the grinding process and a line diagram of the grinding and polishing amount by the CMP process.

FIG. 17 shows a wafer shape line diagram after DSP processing by a conventional polishing method (Comparative Example 1), a wafer shape line diagram after CMP processing, and a polishing removal line diagram by CMP processing.

FIG. 18 is a graph comparing ESFQR (max) by a conventional polishing method (Comparative Example 2) and ESFQR (max) by a polishing method of the present invention (Example 7).

no

Claims (14)

A grinding device includes: A polishing head is used to support a wafer; A disk attached with a polishing cloth for polishing the wafer; A loading table for mounting the wafer on the polishing head; An unloading table for peeling the wafer from the polishing head, The polishing device grinds the wafer supported by the polishing head, wherein The polishing device further includes a local polishing pad that can be moved up and down and is smaller than the wafer. When the local polishing pad is relatively raised toward the polishing head, the wafer and the local polishing pad supported by the polishing head are relatively moved. At the same time, the polishing head supporting the wafer is rotated to locally polish the outer peripheral portion of the wafer in a concentric circle shape. The polishing apparatus according to claim 1, wherein the local polishing pad is polished by contacting the outer periphery of the wafer with a center position of the local polishing pad. The polishing device according to any one of claims 1 or 2, wherein the polishing device includes a back pad cleaning table for cleaning the polishing head, which can be moved up and down, and the local polishing pad is disposed on the back The pad washing table, and the back pad washing table and the local polishing pad can be moved up and down, respectively. A wafer polishing method is a wafer polishing method using the polishing apparatus according to claim 1, wherein Before performing a full single-side polishing of the wafer, The local polishing pad is relatively raised toward the polishing head to contact the wafer supported by the polishing head with the local polishing pad, and the polishing head supporting the wafer is rotated to form a concentric circle. The outer peripheral portion of the wafer is locally polished. The polishing method for a wafer according to claim 4, wherein the local polishing pad is polished by contacting an outer periphery of the wafer with a center position of the local polishing pad. The polishing method for a wafer according to claim 4, wherein the wafer is polished in a radius range of 20 to 50 mm only from the outer peripheral end of the wafer. The method for polishing a wafer according to claim 5, wherein the wafer is polished in a radius range of 20 to 50 mm only from the outer peripheral end of the wafer. The method of polishing a wafer according to claim 4, wherein when the outer peripheral portion of the wafer is locally concentrically polished, the relative height position of the local polishing pad of the polishing head supporting the wafer is changed and controlled. Grinding load. The polishing method for a wafer according to claim 5, wherein when the outer peripheral portion of the wafer is locally polished concentrically, the relative height position of the local polishing pad of the polishing head supporting the wafer is changed and controlled. Grinding load. The method for polishing a wafer according to claim 6, wherein when the outer peripheral portion of the wafer is locally concentrically polished, the relative height position of the local polishing pad of the polishing head supporting the wafer is changed and controlled. Grinding load. The method of polishing a wafer according to claim 7, wherein when the outer peripheral portion of the wafer is locally concentrically polished, the relative height position of the local polishing pad of the polishing head supporting the wafer is changed and controlled. Grinding load. The wafer polishing method according to any one of claims 4 to 11, wherein the locally polished wafer is a double-sided polished wafer. A method for manufacturing a wafer includes a step of locally polishing the outer periphery of the wafer by the method for polishing a wafer according to any one of claims 4 to 11. A manufacturing method of a wafer includes a step of locally polishing a peripheral portion of a wafer by the polishing method for a wafer according to claim 12.