JP2022172822A - Wafer manufacturing method - Google Patents

Abstract

To provide a wafer manufacturing method capable of manufacturing a wafer with good warp and nano-topography.SOLUTION: A wafer manufacturing method, comprising: bringing a first principal surface of a wafer into contact with a resin by pressing the wafer with holding means; pushing out the resin on the first principal surface of the wafer in a state in which a second principal surface of the wafer held by the holding means is released by injecting air between the holding means and the second principal surface from the holding means while pushing out the resin on the first principal surface of the wafer; separating the wafer and the holding means while injecting air; obtaining a composite including a planarizing resin layer by curing the resin after separating the wafer and the holding means; grinding or polishing a second principal surface of the wafer while sucking and holding the composite with the planarizing resin layer as a reference surface; and grinding or polishing the first principal surface of the wafer while sucking and holding the second principal surface of the wafer.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wafer manufacturing method. In particular, the present invention relates to coating formation methods and surface grinding techniques that produce wafers with good warpage and nanotopography.

Substrate wafers are also required to have small and favorable warpage, particularly small and favorable warp, and small and favorable short-wavelength undulations called nanotopography (hereinafter referred to as NT). As a technique for achieving the latter, there is a processing method in which one side of a wafer is coated with a resin and ground (for example, Patent Documents 1 to 4).

For example, in Patent Document 2, after a liquid resin is spread on one surface of a wafer sucked and held by a holding means to form a liquid resin film, air is jetted downward from the suction surface of the holding means, It is described that the wafer is pushed down from the suction surface by the jet pressure of this air, and the wafer is reliably separated from the holding means.

Further, Patent Document 5 discloses storing the pressure change when changing the distance between the pressing portion and the stage while blowing gas from the suction port during setup before coating with resin. ing.

JP 2009-148866 A Japanese Patent Application Laid-Open No. 2020-92161 JP 2007-134371 A JP 2010-155298 A Patent No. 5670208 specification

In the method described in Patent Literature 1, the shape of the holding means (surface plate) when pressing the resin is transferred to the resin thickness distribution, which may affect the wafer shape (warp) after processing. As a conventional technique, Patent Document 2 discloses a method of restoring the deformation element of a wafer by supplying sound waves after resin pressing (after the wafer is separated from an upper surface plate that is a holding means). However, there has been no technique for suppressing the transfer of the shape of the holding means during pressing of the resin.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a wafer manufacturing method capable of manufacturing a wafer having good warp and good nanotopography.

In order to solve the above problems, the present invention provides a method for manufacturing a wafer, comprising:
providing a wafer having a first major surface and a second major surface opposite the first major surface;
holding the second major surface of the wafer by holding means;
disposing a resin in a plastic state so as to face the first main surface of the wafer;
pressing the wafer by the holding means to bring the first main surface of the wafer into contact with the resin;
While spreading the resin over the first main surface of the wafer, air is jetted from the holding means between the holding means and the second main surface, whereby the second main surface of the wafer is spreading the resin over the first main surface of the wafer in a state in which the holding by the holding means is released;
forming a gap between the wafer and the holding means while performing the air injection to separate the wafer and the holding means;
After the separation between the wafer and the holding means, the resin is cured to form a flattened resin layer to obtain a composite including the wafer and the flattened resin layer in contact with the first main surface of the wafer. When,
sucking and holding the composite with the planarizing resin layer as a reference surface, and grinding or polishing the second main surface of the wafer in that state;
removing the planarizing resin layer from the wafer;
There is provided a method for manufacturing a wafer, comprising holding the second main surface of the wafer by suction, and grinding or polishing the first main surface of the wafer in that state.

According to the wafer manufacturing method of the present invention, the resin is spread over the first main surface of the wafer in a state in which the second main surface of the wafer is released from the holding means while air is being injected, and the resin is spread while air is being injected. By separating the wafer and the holding means and curing the resin after this separation, it is possible to suppress the transfer of the shape of the holding means to the wafer, and as a result, a wafer with good warp and good nanotopography can be obtained. can be manufactured.

By standing by without changing the height of the holding means at the separation between the wafer and the holding means, the gap is formed between the wafer and the holding means by the flow of the resin, and the gap is closed. Formation may be determined from the load values applied to the retaining means.

For example, the wafer can be separated from the holding means by waiting without changing the height of the holding means while blowing air.

Alternatively, in the separation between the wafer and the holding means, the gap between the wafer and the holding means may be formed by retracting the holding means.

In this way, the wafer and the holding means may be separated by retracting the holding means with respect to the wafer. By doing so, it is possible to secure a sufficient gap between the wafer and the holding means in a relatively short period of time.

As described above, according to the wafer manufacturing method of the present invention, it is possible to suppress the transfer of the shape of the holding means to the wafer, and as a result, the warp is small and favorable, and the nanotopography is small and favorable. can be manufactured.

1 is a schematic flow chart showing an example of a method for manufacturing a wafer according to the present invention; FIG. FIG. 3 is a schematic flow chart showing another example of the wafer manufacturing method of the present invention. It is a schematic flow diagram showing an example of a conventional wafer manufacturing method.

As described above, there has been a demand for the development of a wafer manufacturing method capable of manufacturing wafers with good warp and good nanotopography.

As a result of intensive studies on the above problems, the inventors of the present invention spread the resin over the first main surface of the wafer in a state in which the holding means of the second main surface of the wafer is released while injecting air. By separating the wafer and the holding means while spraying, and curing the resin after this separation, it is possible to suppress the shape of the holding means from being transferred to the wafer. The inventors have found that good wafers can be produced, and completed the present invention.

That is, the present invention is a method for manufacturing a wafer,
providing a wafer having a first major surface and a second major surface opposite the first major surface;
holding the second major surface of the wafer by holding means;
disposing a resin in a plastic state so as to face the first main surface of the wafer;
pressing the wafer by the holding means to bring the first main surface of the wafer into contact with the resin;
While spreading the resin over the first main surface of the wafer, air is jetted from the holding means between the holding means and the second main surface, whereby the second main surface of the wafer is spreading the resin over the first main surface of the wafer in a state in which the holding by the holding means is released;
forming a gap between the wafer and the holding means while performing the air injection to separate the wafer and the holding means;
After the separation between the wafer and the holding means, the resin is cured to form a flattened resin layer to obtain a composite including the wafer and the flattened resin layer in contact with the first main surface of the wafer. When,
sucking and holding the composite with the planarizing resin layer as a reference surface, and grinding or polishing the second main surface of the wafer in that state;
removing the planarizing resin layer from the wafer;
The method of manufacturing a wafer includes holding the second main surface of the wafer by suction, and grinding or polishing the first main surface of the wafer in that state.

On the other hand, Patent Literatures 1 to 5 neither describe nor suggest that the resin is spread over the wafer while air is jetted from the holding means to separate the wafer and the holding means.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereto. In the drawings, for the sake of explanation, the unevenness of the wafer before grinding and the warp of the holding means are exaggerated. The warpage of the means is not limited to the magnitude shown.

1 and 2 are schematic flow charts showing examples of the wafer manufacturing method of the present invention, respectively. The example of FIG. 2 is the same as the example of FIG. 1 except that the steps of FIGS. 2E and 2F are different from those of FIGS. 1E and 1F. In the following, the example of FIG. 1 will be described as a representative, and only the steps of FIGS. 2(E) and 2(F) will be described for the example of FIG.

First, as shown in FIG. 1A, a wafer 1 having a first principal surface 1A and a second principal surface 1B opposite to the first principal surface 1A is prepared. The wafer 1 to be prepared is not particularly limited.

Next, as shown in FIG. 1B, the second main surface 1B of the wafer 1 is held by the holding means 2. Next, as shown in FIG. In this example, the second main surface 1B of the wafer 1 is vacuum-sucked and held by the upper surface plate 2 as holding means. The upper surface plate 2 can vacuum-suck the wafer 1 by applying vacuum suction through the through holes 2a vertically penetrating the upper surface plate 2. As shown in FIG.

On the other hand, as shown in FIG. 1(B), a resin 5 in a plastic state is arranged so as to face the first main surface 1A of the wafer 1 . In this example, a light-transmitting film 4 is laid on a glass surface plate 3 (lower surface plate) having a flat surface, and a resin 5 in a plastic state, for example a liquid state, is supplied thereon. The resin 5 is not particularly limited as long as it can be cured.

Next, as shown in FIG. 1(C), the wafer 1 is pressed by the holding means 2 to bring the first main surface 1A of the wafer 1 into contact with the resin 5. Next, as shown in FIG. In this example, the upper surface plate 2 as a holding means is lowered, and the wafer 1 adsorbed and held on the upper surface plate 2 is pressed against the resin 5 from above so that the first main surface 1A of the wafer 1 is brought into contact with the resin 5. .

After the resin 5 and the wafer 1 are brought into contact with each other, air injection is started. In this example, as shown in FIG. 1(D), at the point where the resin 5 and the first main surface 1A of the wafer 1 contact (the position where the load applied to the upper surface plate 2 exceeds the set load (A)) , air injection from the upper surface plate 2 to the space between the upper surface plate 2 and the second main surface 1B of the wafer 1 is started. The air can be injected through the through holes 2a of the upper surface plate 2, for example.

Subsequently, the upper surface plate 2 is lowered until the resin 5 spreads sufficiently while continuing the air injection. That is, the air is jetted while spreading the resin 5 over the first main surface 1A of the wafer 1 . Accordingly, in the present invention, the resin 5 is spread over the first main surface 1 of the wafer 1 while the second main surface 1B of the wafer 1 is released from the holding means 2 .

Part of the second main surface 1B of the wafer 1 may come into contact with the upper surface plate 2 (for example, point contact) while the air is being sprayed. Keep hold open.

By pressing the resin 5 from above while injecting air in this way, an air cushion layer is formed between the upper surface plate 2 and the second main surface 1B of the wafer 1, whereby the shape of the upper surface plate 2 is formed. can be suppressed from being transferred to the wafer 1.

Next, the lowering of the upper surface plate 2 is stopped by the set stopping load (B). In this example, it waits without changing the height of the upper platen 2 which is the holding means. During this time, the air injection continues. As a result, the resin 5 spreads naturally, and a gap 2b is formed between the wafer 1 and the upper surface plate 2 as shown in FIG. 1(E). Thereby, the wafer 1 and the upper surface plate 2 are separated.

Subsequently, as shown in FIG. 1(E), the injection of air is stopped at the timing when the resin 5 spreads naturally and the space between the upper surface plate 2 and the wafer 1 is sufficiently secured. For example, the load value applied to the upper surface plate 2 is grasped, and when the load is reduced to the set load (C), the air injection is stopped.

Alternatively, as shown in FIG. 2(E), after the set stopping load (B) is detected, the upper surface plate 2 is retracted (moved upward) while continuing the air injection, and the upper surface plate 2 and the wafer 1, the air injection is stopped to separate the upper surface plate 2 and the wafer 1, and a gap 2b may be formed therebetween.

By stopping the air injection while a sufficient gap is secured between the wafer 1 and the upper surface plate 2, it is possible to prevent the wafer 1 and the upper surface plate 2 from contacting each other again due to the elasticity of the wafer 1 and the resin 5. can. As a result, it is possible to more reliably prevent the shape of the upper surface plate 2 from being transferred to the thickness of the resin through the wafer 1 .

Next, after separating the wafer 1 and the upper surface plate 2, as shown in FIG. A composite 10 including the contacting planarizing resin layer 6 is obtained.

In this example, since the lower surface plate 3 is a glass surface plate, ultraviolet rays are irradiated from below the lower surface plate 3, and the ultraviolet rays pass through the lower surface plate 3 and the light-transmitting film 4, hit the resin 5, and reach the resin 5. can be cured. Incidentally, the means for curing the resin 5 is not limited to ultraviolet irradiation, and can be appropriately changed according to the type of the resin 5 . For example, if the resin 5 is a thermosetting resin, it can be cured by an external stimulus such as heat.

In the example shown in FIG. 2 as well, after the wafer 1 and the upper surface plate 2 are separated as shown in FIG. 2(E), the resin 5 is cured in the state shown in FIG. .

Next, as shown in FIG. 1G, the composite 10 is transferred to, for example, a grinding stage 20 using the planarizing resin layer 6 as a reference surface, and the composite 10 is held by suction. The grinding stage 20 is made of porous ceramic, for example, and can hold the composite 10 by vacuum adsorption.

Next, as shown in FIG. 1(H), the second main surface 1B of the wafer 1 is ground or polished while being sucked and held by the grinding stage 20 . In this example, the grinding wheel 30 is used to grind (first grind) the second main surface 1B of the wafer 1 to obtain the ground second main surface 1C. For example, the grinding is performed so that the TTV after grinding is 1 μm or less.

Next, as shown in FIG. 1(I), the planarizing resin layer 6 is removed from the wafer 1 . In this example, the light transmissive film 4 is also removed at the same time.

Next, as shown in FIG. 1(J), the wafer 1 is turned over, and the ground second main surface 1C of the wafer 1 is held by suction on the grinding stage 20. In this state, the first main surface 1A of the wafer 1 is held. Grind or polish. In this example, the grinding wheel 30 is used to grind the first main surface 1A of the wafer 1 to obtain the ground first main surface 1D.

The wafer 1 thus obtained has a ground first main surface 1D and a ground second main surface 1C, as shown in FIG. 1(K). This wafer 1 spreads the resin 5 over the first main surface 1A of the wafer 1 in a state in which the second main surface 1B of the wafer 1 is released from the holding means (upper surface plate) 2 while air is injected, The shape of the holding means (upper surface plate) 2 can be prevented from being transferred to the wafer 1 by separating the wafer 1 and the holding means 2 while blowing air, and curing the resin 5 after this separation. . That is, it is possible to manufacture good wafers with small warp. Alternatively, the second main surface 1B is ground while the planarizing resin layer 6 is formed in contact with the first main surface 1A of the wafer 1, and then the wafer 1 is turned over to grind the first main surface 1A. , the nanotopography can be well below target.

On the other hand, in the conventional wafer manufacturing method, it is not possible to manufacture good wafers with a small warp, as will be described below with reference to FIG. 3, for example.

The conventional wafer manufacturing method shown in a schematic flow diagram in FIG. 3 is mainly different from the wafer manufacturing method of the present invention shown in FIG. 3(D) as an example in FIGS. . That is, in the conventional method shown in FIG. 3, even after the resin 5 and the wafer 1 come into contact with each other, the second main surface 1B of the wafer 1 is held by the holding means (upper surface plate) 2 without air injection. In this state, the resin 5 continues to spread over the first main surface 1A of the wafer 1. As shown in FIG. As a result, as shown in FIG. 3(E), after releasing the holding by the upper surface plate 2, the wafer 1 having the shape of the upper surface plate 2 transferred thereon is obtained. As a result, the wafer 1 obtained after grinding the second main surface 1B and the first main surface 1A has a large warp as shown in FIG. 3(K).

EXAMPLES The present invention will be specifically described below using Examples and Comparative Examples, but the present invention is not limited to these.

[Experiment contents]
(Formation of planarizing resin layer on wafer)
<Examples 1-1 to 1-4>
In Examples 1-1 to 1-4, according to the same flow as in FIGS. 1(A) to 1(F), under the following conditions, the wafer and the planarizing resin layer in contact with the first main surface of the wafer are included. A composite was produced.

◇Covering (flattening resin layer) forming conditions ・As a wafer, a P-type Si single crystal wafer with a diameter of 300 mm was used.
- A UV curable resin was used as the resin, and a PET film was used as the light transmissive film.
- A flat glass surface plate (lower surface plate) was covered with a PET film, and 10 ml of a UV curable resin was dropped onto the PET film.
- The resin was pressed by holding the second main surface of the wafer by suction on a ceramic surface plate (upper surface plate) and descending toward the resin.

・In pressure control, the servo motor that holds the upper surface plate is driven, and at the timing when a predetermined load (A) of 100 N is detected, vacuum suction is stopped and air injection is started.
- The upper surface plate was lowered while air injection was continued, and the lowering of the upper surface plate was stopped with a stop load (B) of 2000N. As a result, the resin was spread over the first main surface of the wafer while the second main surface of the wafer was released from being held by the upper surface plate.
・By waiting for air injection, the resin spreads naturally and the load applied to the upper surface plate is reduced. As a result, a gap was formed between the wafer and the upper surface plate to separate the wafer and the upper surface plate.
・After the load applied to the upper surface plate decreased to the set load (C), the air injection was stopped.
- The resin was cured by irradiating ultraviolet rays to form a flattened resin layer. (There is a gap between the wafer and the upper surface plate during UV irradiation.)
・Here, considering the effect of transfer due to the gap between the wafer and the upper surface plate until the air injection is stopped, the set load (C) is 1500 N (Example 1-1) and 1000 N (Example 1-2). , 500N (Example 1-3), and 100N (Example 1-4).
- A UV-LED with a wavelength of 365 nm was used as a light source for curing the resin.

<Comparative Example 2>
In Comparative Example 2, a composite including a wafer and a planarizing resin layer in contact with the first main surface of the wafer was produced according to the same flow as in FIGS. 3(A) to 3(F). Specifically, the pressing control was changed from Example 1-1 as follows.

- In the pressing control, the upper surface plate was driven by the servomotor holding the upper surface plate, and the lowering of the upper surface plate was stopped with a stop load (B) of 2000N. During this time, the resin was spread over the first main surface of the wafer while holding the wafer on the upper surface plate without blowing air.
・After that, vacuum adsorption was stopped and air injection was started.
・The upper surface plate was lifted and stopped, and then the air injection was stopped. Thereby, a gap was formed between the wafer and the upper surface plate.
・The resin was cured by irradiating ultraviolet rays to form a flattened resin layer. (There is a gap between the wafer and the upper surface plate during UV irradiation.)
- A UV-LED with a wavelength of 365 nm was used as a light source for curing the resin.

<Examples 2-1 to 2-3>
In Examples 2-1 to 2-3, a composite including a wafer and a planarizing resin layer in contact with the first main surface of the wafer was produced according to the same flow as in FIGS. 2(A) to 2(F). . Specifically, the pressing control was changed from Example 1-1 as follows.

・In pressure control, the servo motor that holds the upper surface plate is driven, and at the timing when a predetermined load (A) of 100 N is detected, vacuum suction is stopped and air injection is started.
- The upper surface plate was lowered while air injection was continued, and the lowering of the upper surface plate was stopped with a stop load (B) of 2000N. As a result, the resin was spread over the first main surface of the wafer while the second main surface of the wafer was released from being held by the upper surface plate.
- Next, while continuing the air injection, the upper surface plate was lifted by a predetermined distance L and stopped, and then the air injection was stopped. Thereby, a gap was formed between the wafer and the upper surface plate.
・The resin was cured by irradiating ultraviolet rays to form a flattened resin layer. (There is a gap between the wafer and the upper surface plate during UV irradiation.)
・Here, considering the effect of transfer due to the gap between the wafer and the upper surface plate, the predetermined distance L is 2 μm (Example 2-1), 5 μm (Example 2-2), 10 μm (Example 2 -3) was carried out.
- A UV-LED with a wavelength of 365 nm was used as a light source for curing the resin.

(grinding)
<Comparative Example 1>
In Comparative Example 1, a P-type Si single crystal wafer with a diameter of 300 mm similar to that used in Example 1-1 was prepared, and this wafer was ground under the following conditions.

<Examples 1-1 to 1-4, Comparative Example 2, Examples 2-1 to 2-3>
In Examples 1-1 to 1-4, Comparative Example 2, and Examples 2-1 to 2-3, the previously prepared composites were ground under the following conditions.

◇Grinding conditions ・For grinding, DFG8360 manufactured by Disco was used.
・As a grinding wheel, a diamond abrasive grain was used.
Since the subsequent grinding method is different between <Comparative Example 1> and other (<Comparative Example 2>, <Examples 1-1 to 1-4>, <Examples 2-1 to 2-3>), described in

<Comparative Example 1>
First grinding conditions (back surface (second main surface) grinding)
・The front surface (first main surface) of the wafer was vacuum-adsorbed to the grinding stage, and the back surface (second main surface) was ground. (without flattening resin layer)

Second grinding conditions (surface (first main surface) grinding)
- The first ground surface (the ground second main surface) was vacuum-adsorbed to the grinding stage, and the surface (first main surface) was ground.
・By adjusting the axial angle of the chuck table, the wafer thickness variation was adjusted to 1 μm or less.

<Comparative Example 2>, <Examples 1-1 to 1-4>, <Examples 2-1 to 2-3>
First grinding conditions (back surface (second main surface) grinding)
- The coating (flattening resin layer) side of the composite was vacuum-sucked, and the back surface (second main surface) was ground.
- The flattening resin layer was peeled off after grinding.

Second grinding conditions (surface (first main surface) grinding)
- The first ground surface (the ground second main surface) was vacuum-adsorbed to the grinding stage, and the surface (first main surface) was ground.
・By adjusting the axial angle of the chuck table, the wafer thickness variation was adjusted to 1 μm or less.

(mirror polishing)
The front and back surfaces (ground first and second main surfaces) of each wafer ground as described above were mirror-polished.

[Measurement result]
Warp and nanotopography (NT) of each wafer after mirror polishing were measured as follows.

Warp and NT were measured using an optical interference type flatness/NT measuring device (KLA: WaferSight2+).
SQMM 2 mm x 2 mm was used as the index for NT.
The results are shown in Table 1 below.

In Comparative Example 1, since the grinding was performed without forming the planarizing resin layer, both Warp and NT were defective.

In Comparative Example 2, NT became good by forming a flattening resin layer and grinding, but because the resin continued to spread over the first main surface of the wafer while maintaining the holding by the upper surface plate. , transfer of the surface plate shape occurred, resulting in warp failure.

On the other hand, in Examples 1-1, 1-2, 1-3 and 1-4, while performing air injection, the resin was spread over the first main surface of the wafer in a state in which the holding by the upper surface plate was released, By forming the flattened resin layer by curing the resin while the upper surface plate and the wafer are separated from each other, transfer of the surface plate shape is alleviated, and the warp is improved as compared with Comparative Example 2.

In particular, in Examples 1-3 and 1-4 in which the air injection stop load was set to 500 N or less, a sufficient gap was secured between the wafer and the upper surface plate when the air injection was stopped, so the warp was further improved.

On the other hand, in Examples 2-1, 2-2 and 2-3, while performing air injection, the resin was spread over the first main surface of the wafer in a state in which the holding by the upper surface plate was released, and By forming the flattened resin layer by curing the resin while the platen and the wafer are separated from each other, transfer of the platen shape is alleviated, and the warp is improved as compared with Comparative Example 2.

In particular, in Examples 2-2 and 2-3 in which the distance for retracting the upper surface plate during air injection was set to 5 μm or more, a sufficient gap was secured between the wafer and the upper surface plate when air injection was stopped. Warp is even better.

From the above results, when forming the planarizing resin layer, while performing air injection, the resin was spread over the first main surface of the wafer in a state in which the holding by the upper surface plate was released, and the upper surface plate and the wafer were separated. It can be seen that by forming the flattening resin layer by curing the resin in this state, it is possible to prevent the surface plate shape from being transferred.

Furthermore, when the upper surface plate and the wafer are separated by waiting the upper surface plate, it is more desirable to set the load to 500 N or less when the air injection is stopped.

Also, from the viewpoint of shortening the machining time, it is better to retract the upper surface plate during the air injection, and more preferably, the distance for retracting the upper surface plate is 5 μm or more.

It should be noted that the present invention is not limited to the above embodiments. The above-described embodiment is an example, and any device having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect is the present invention. included in the technical scope of

DESCRIPTION OF SYMBOLS 1... Wafer 1A... First main surface 1B... Second main surface 1C... Grinded second main surface 1D... Grinded first main surface 2... Holding means (upper surface plate) 2a... Through hole 2b... Gap 3... Lower platen 4... Light transmissive film 5... Resin 6... Planarizing resin layer 10... Composite 20... Grinding stage 30... Grinding wheel.

Claims (3)

A wafer manufacturing method comprising:
providing a wafer having a first major surface and a second major surface opposite the first major surface;
holding the second major surface of the wafer by holding means;
disposing a resin in a plastic state so as to face the first main surface of the wafer;
pressing the wafer by the holding means to bring the first main surface of the wafer into contact with the resin;
While spreading the resin over the first main surface of the wafer, air is jetted from the holding means between the holding means and the second main surface, whereby the second main surface of the wafer is spreading the resin over the first main surface of the wafer in a state in which the holding by the holding means is released;
forming a gap between the wafer and the holding means while performing the air injection to separate the wafer and the holding means;
After the separation between the wafer and the holding means, the resin is cured to form a flattened resin layer to obtain a composite including the wafer and the flattened resin layer in contact with the first main surface of the wafer. When,
sucking and holding the composite with the planarizing resin layer as a reference surface, and grinding or polishing the second main surface of the wafer in that state;
removing the planarizing resin layer from the wafer;
A method of manufacturing a wafer, comprising holding the second main surface of the wafer by suction, and grinding or polishing the first main surface of the wafer in that state. By standing by without changing the height of the holding means at the separation between the wafer and the holding means, the gap is formed between the wafer and the holding means by the flow of the resin, and the gap is closed. 2. The method of manufacturing a wafer according to claim 1, wherein the formation of the wafer is determined from the value of the load applied to the holding means. 2. The method of manufacturing a wafer according to claim 1, wherein the space between the wafer and the holding means is formed by retracting the holding means to form the gap between the wafer and the holding means.

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