Wafer manufacturing method

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

[Technical field]

[0001] The present invention relates to a wafer manufacturing method, and more particularly to a coating method and surface grinding technology for manufacturing wafers with good warpage and nanotopography. [Background technology]

[0002] Substrate wafers are required to have small and good warpage, especially small and good warp, and small and good short wavelength waviness called nanotopography (hereafter 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 resin and then ground (for example, Patent Documents 1 to 4).

[0003] For example, Patent Document 2 describes a method in which liquid resin is spread onto one side of a wafer held by suction using a holding means to form a film of liquid resin, and then air is sprayed downward from the suction surface of the holding means, and the pressure of this air spray presses the wafer down from the suction surface, thereby reliably releasing the wafer from the holding means.

[0004] Furthermore, Patent Document 5 discloses that during setup before resin coating, the pressure change that occurs when the distance between the pressing part and the stage is changed while gas is ejected from a suction port is stored. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-148866 A [Patent Document 2] JP 2020-92161 A [Patent Document 3] JP 2007-134371 A [Patent Document 4] JP 2010-155298 A [Patent Document 5] Patent No. 5670208 Specification Summary of the Invention [Problem to be solved by the invention]

[0006] In the method described in Patent Document 1, the shape of the holding means (platen) during resin pressing is transferred to the resin thickness distribution, which can affect the wafer shape (warpage) after processing. As a conventional technique, Patent Document 2 discloses a method of restoring the deformation elements of the wafer by supplying sound waves after resin pressing (after the wafer is separated from the upper platen, which is the holding means), but there was no technique for suppressing the transfer of the holding means shape during resin pressing.

[0007] The present invention has been made to solve the above problems, and has an object to provide a wafer manufacturing method capable of manufacturing wafers having good warp and good nanotopography. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a method for manufacturing a wafer, comprising the steps of: providing a wafer having a first major surface and a second major surface opposite the first major surface; holding the second main surface of the wafer with a holding means; disposing a resin in a plastic state facing the first main surface of the wafer; pressing the wafer with the holding means to bring the first main surface of the wafer into contact with the resin; While spreading the resin on the first main surface of the wafer, air is injected from the holding means between the holding means and the second main surface, thereby spreading the resin on the first main surface of the wafer in a state where the second main surface of the wafer is released from the holding means; forming a gap between the wafer and the holding means while performing the air injection, thereby separating the wafer from the holding means; After the wafer is separated from the holding means, the resin is cured to form a planarized resin layer, thereby obtaining a composite including the wafer and the planarized resin layer in contact with the first main surface of the wafer; adsorbing and holding the composite using 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 present invention provides 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 this state.

[0009] According to the wafer manufacturing method of the present invention, while releasing the holding means from holding the second main surface of the wafer, the resin is spread over the first main surface of the wafer while spraying air, the wafer is separated from the holding means while spraying air, and the resin is hardened after separation, thereby preventing the shape of the holding means from being transferred to the wafer, and as a result, a wafer with good warp and good nanotopography can be manufactured.

[0010] By waiting at the distance between the wafer and the holding means without changing the height of the holding means, a gap is formed between the wafer and the holding means by the flow of the resin, and the formation of the gap can be grasped from the load value applied to the holding means.

[0011] For example, the wafer can be separated from the holding means by waiting without changing the height of the holding means while spraying air.

[0012] Alternatively, in the space between the wafer and the holding means, the gap between the wafer and the holding means may be formed by retracting the holding means.

[0013] In this manner, the wafer may be spaced apart from the holding means by retracting the holding means from the wafer, thereby ensuring a sufficient gap between the wafer and the holding means in a relatively short time. Effect of the Invention

[0014] As described above, the wafer manufacturing method of the present invention can prevent the shape of the holding means from being transferred to the wafer, and as a result, it is possible to manufacture wafers with small and favorable warps and small and favorable nanotopography. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic flow diagram showing an example of a method for producing a wafer according to the present invention. [Diagram 2] FIG. 4 is a schematic flow diagram showing another example of the wafer manufacturing method of the present invention. [Diagram 3] FIG. 1 is a schematic flow diagram showing an example of a conventional wafer manufacturing method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] As described above, there has been a demand for the development of a wafer manufacturing method capable of manufacturing wafers having good warp and good nanotopography.

[0017] As a result of extensive research into the above-mentioned problems, the inventors discovered that by spreading the resin over the first main surface of the wafer while releasing the holding means from holding the second main surface of the wafer while spraying air, separating the wafer from the holding means while spraying air, and hardening the resin after separation, it is possible to prevent the shape of the holding means from being transferred to the wafer, and as a result, it is possible to manufacture a wafer with good warp and good nanotopography, and thus completed the present invention.

[0018] That is, the present invention is a method for manufacturing a wafer, comprising the steps of: providing a wafer having a first major surface and a second major surface opposite the first major surface; holding the second main surface of the wafer with a holding means; disposing a resin in a plastic state facing the first main surface of the wafer; pressing the wafer with the holding means to bring the first main surface of the wafer into contact with the resin; While spreading the resin on the first main surface of the wafer, air is injected from the holding means between the holding means and the second main surface, thereby spreading the resin on the first main surface of the wafer in a state where the second main surface of the wafer is released from the holding means; forming a gap between the wafer and the holding means while performing the air injection, thereby separating the wafer from the holding means; After the wafer is separated from the holding means, the resin is cured to form a planarized resin layer, thereby obtaining a composite including the wafer and the planarized resin layer in contact with the first main surface of the wafer; adsorbing and holding the composite using 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 for manufacturing a wafer includes: suction-holding the second main surface of the wafer, and grinding or polishing the first main surface of the wafer in that state.

[0019] On the other hand, Patent Documents 1 to 5 do not describe or suggest spreading the resin over the wafer while injecting air from the holding means, and separating the wafer from the holding means.

[0020] The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto. In the drawings, for the purpose of explanation, the unevenness of the wafer before grinding and the warpage of the holding means are exaggerated, but in the wafer manufacturing method of the present invention, the unevenness of the wafer before grinding and the warpage of the holding means are not limited to those as large as those shown in the drawings.

[0021] Figures 1 and 2 are schematic flow diagrams showing examples of the wafer manufacturing method of the present invention. The example of Figure 2 is the same as the example of Figure 1 except that the steps of Figure 2(E) and Figure 2(F) are different from Figure 1(E) and Figure 1(F). In the following, the example of Figure 1 will be described as a representative, and for the example of Figure 2, only the steps of Figure 2(E) and Figure 2(F) will be described.

[0022] 1(A), a wafer 1 having a first main surface 1A and a second main surface 1B opposite to the first main surface 1A is prepared. There are no particular limitations on the wafer 1 to be prepared.

[0023] 1(B), the second main surface 1B of the wafer 1 is held by a holding means 2. In this example, the second main surface 1B of the wafer 1 is held by vacuum adsorption to an upper surface plate 2 serving as a holding means. The upper surface plate 2 can vacuum adsorb the wafer 1 by applying a vacuum through a through hole 2a that penetrates the upper surface plate 2 from top to bottom.

[0024] 1(B), resin 5 in a plastic state is placed 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 resin 5 in a plastic state, for example, in a liquid state, is supplied onto the film 4. There are no particular limitations on the resin 5 as long as it can be hardened.

[0025] 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. In this example, the upper surface plate 2 serving as the holding means is lowered to press the wafer 1 held by suction on the upper surface plate 2 against the resin 5 from above, so that the first main surface 1A of the wafer 1 comes into contact with the resin 5.

[0026] Air injection is started after the resin 5 and the wafer 1 come into contact with each other. In this example, as shown in Fig. 1(D), air injection is started from the upper platen 2 to between the upper platen 2 and the second main surface 1B of the wafer 1 at the point where the resin 5 and the first main surface 1A of the wafer 1 come into contact with each other (the position where the load applied to the upper platen 2 exceeds the set load (A)). Air injection can be performed, for example, through the through-hole 2a of the upper platen 2.

[0027] Next, while continuing the air injection, the upper platen 2 is lowered until the resin 5 is sufficiently spread. That is, the air is injected while spreading the resin 5 over the first main surface 1A of the wafer 1. In this way, 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.

[0028] During air injection, a portion of the second main surface 1B of the wafer 1 may be in contact (e.g., point contact) with the upper platen 2, but the second main surface 1B of the wafer 1 remains released from the holding means 2.

[0029] By spraying air in this manner and pressing the resin 5 from above, an air cushion layer is formed between the upper platen 2 and the second main surface 1B of the wafer 1, thereby preventing the shape of the upper platen 2 from being transferred to the wafer 1.

[0030] Next, the descent of the upper platen 2 is stopped at the set stopping load (B). In this example, the height of the upper platen 2, which is the holding means, is not changed and the process waits. Air injection continues during this time. As a result, the resin 5 naturally spreads, and a gap 2b is formed between the wafer 1 and the upper platen 2, as shown in FIG. 1(E). This causes the wafer 1 and the upper platen 2 to be separated.

[0031] 1(E), the air injection is stopped when the resin 5 naturally spreads and a sufficient gap is secured between the upper platen 2 and the wafer 1. For example, the load value applied to the upper platen 2 is grasped, and when the load decreases to the set load (C), the air injection is stopped.

[0032] Alternatively, as shown in FIG. 2(E), after the set stop load (B) is detected, the upper platen 2 is withdrawn (moved upward) while continuing the air injection, and when a sufficient distance between the upper platen 2 and the wafer 1 is secured, the air injection is stopped to separate the upper platen 2 and the wafer 1, thereby forming a gap 2b between them.

[0033] By stopping the air injection while a sufficient gap is maintained between the wafer 1 and the upper platen 2, it is possible to prevent the wafer 1 and the upper platen 2 from coming into contact again due to the elasticity of the wafer 1 and the resin 5. As a result, it is possible to more reliably prevent the shape of the upper platen 2 from being transferred through the wafer 1 to the thickness of the resin.

[0034] Next, after the wafer 1 is separated from the upper platen 2, the resin 5 is hardened to form a planarized resin layer 6, as shown in FIG. 1(F), to obtain a composite 10 including the wafer 1 and the planarized resin layer 6 in contact with the first main surface 1A of the wafer 1.

[0035] In this example, since the lower surface plate 3 is a glass surface plate, by irradiating ultraviolet light from below the lower surface plate 3, the ultraviolet light passes through the lower surface plate 3 and the light-transmitting film 4, hits the resin 5, and hardens the resin 5. Note that the means for hardening the resin 5 is not limited to ultraviolet light irradiation, and can be changed appropriately depending on the type of resin 5. For example, when the resin 5 is a thermosetting resin, hardening can also be performed by an external stimulus such as heat.

[0036] In the example shown in FIG. 2, after the wafer 1 and the upper platen 2 are separated as shown in FIG. 2(E), the resin 5 is cured in the state shown in FIG. 2(F) to form a flattened resin layer 6.

[0037] 1(G), the composite 10 is transferred to, for example, a grinding stage 20 using the flattening resin layer 6 as a reference surface, and the composite 10 is adsorbed and held. The grinding stage 20 is made of, for example, porous ceramic, and can hold the composite 10 by vacuum adsorption.

[0038] 1(H), the second main surface 1B of the wafer 1 is ground or polished while being held by suction on the grinding stage 20. In this example, the second main surface 1B of the wafer 1 is ground (first grinding) using a grinding wheel 30 to obtain a ground second main surface 1C. For example, grinding is performed so that the TTV after grinding is 1 μm or less.

[0039] 1(I), the flattening resin layer 6 is removed from the wafer 1. In this example, the light-transmitting film 4 is also removed at the same time.

[0040] 1(J), the wafer 1 is turned over, and the ground second main surface 1C of the wafer 1 is suction-held by a grinding stage 20, and in this state, the first main surface 1A of the wafer 1 is ground or polished. In this example, the first main surface 1A of the wafer 1 is ground using a grinding wheel 30 to obtain a ground first main surface 1D.

[0041] 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). The wafer 1 is pressed and spread on the first main surface 1A of the wafer 1 while air is being sprayed, and the wafer 1 and the holding means 2 are separated while air is sprayed. After the separation, the resin 5 is hardened, thereby preventing the shape of the holding means (upper platen) 2 from being transferred to the wafer 1. In other words, a good wafer with small warp can be manufactured. In addition, the second main surface 1B is ground while the flattened 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 and the first main surface 1A is ground, thereby making the nanotopography less than the target value and improving it.

[0042] On the other hand, in the conventional wafer manufacturing method, as will be described below with reference to FIG. 3, it is not possible to manufacture a good wafer with a small warp.

[0043] The conventional wafer manufacturing method, the schematic flow diagram of which is shown in FIG. 3, is mainly different from the wafer manufacturing method of the present invention, the example of which is shown in FIG. 1(D) and FIG. 2(D). 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 resin 5 continues to be spread on the first main surface 1A of the wafer 1 while the second main surface 1B of the wafer 1 is held by the holding means (upper platen) 2 without air injection. As a result, as shown in FIG. 3(E), after the holding by the upper platen 2 is released, the wafer 1 to which the shape of the upper platen 2 is transferred is obtained. As a result, the wafer 1 obtained after the second main surface 1B and the first main surface 1A are ground has a large warp, as shown in FIG. 3(K). EXAMPLES

[0044] The present invention will be specifically described below using examples and comparative examples, but the present invention is not limited to these.

[0045] [Experimental content] (Formation of a planarizing resin layer on a wafer) <Examples 1-1 to 1-4> In Examples 1-1 to 1-4, a composite including a wafer and a planarizing resin layer in contact with a first main surface of the wafer was produced under the following conditions according to a flow similar to that shown in FIGS. 1(A) to 1(F).

[0046] ◇Covering (flattening resin layer) formation conditions The wafer used was a P-type Si single crystal wafer with a diameter of 300 mm. -UV-curable resin was used as the resin, and PET film was used as the light-transmitting film. A PET film was placed on a flat glass platen (lower platen), and 10 ml of UV-curable resin was dropped onto the PET film. The second main surface of the wafer was held by suction on a ceramic platen (upper platen) and lowered toward the resin, pressing the resin.

[0047] For pressure control, the servo motor holding the upper platen was used to drive the device, and when a specified load (A) of 100N was detected, the vacuum suction was stopped and air injection was started. While continuing the air injection, the upper platen was lowered and the descent of the upper platen was stopped at a stop load (B) of 2000 N. This allowed the resin to be spread over the first main surface of the wafer while releasing the upper platen from holding the second main surface of the wafer. By waiting while the air was injected, the resin spread naturally, and the load on the upper platen was reduced. This created a gap between the wafer and the upper platen, separating them. After the load on the upper platen decreased to the set load (C), the air injection was stopped. The resin was irradiated with ultraviolet light to harden it and create a flattened resin layer. (There was a gap between the wafer and the upper platen when ultraviolet light was irradiated.) Here, taking into consideration the effect of transfer due to the gap between the wafer and the upper platen until the air injection was stopped, four examples were carried out with the set load (C) set to 1500 N (Example 1-1), 1000 N (Example 1-2), 500 N (Example 1-3), and 100 N (Example 1-4). A UV-LED with a wavelength of 365 nm was used as the light source for curing the resin.

[0048] <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 Figures 3(A) to 3(F). Specifically, the pressure control was changed from that in Example 1-1 as follows.

[0049] In the pressure control, the servo motor holding the upper platen was used to drive the descent of the upper platen, and the stopping load (B) was 2000 N. During this time, no air was injected, and the resin was spread over the first main surface of the wafer while the wafer was held by the upper platen. After that, the vacuum suction was stopped and air injection was started. The upper platen was raised and stopped, and the air injection was stopped. This created a gap between the wafer and the upper platen. The resin was irradiated with ultraviolet light to harden it and create a flattened resin layer. (There was a gap between the wafer and the upper platen when ultraviolet light was irradiated.) A UV-LED with a wavelength of 365 nm was used as the light source for curing the resin.

[0050] <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 Figures 2(A) to 2(F). Specifically, the pressure control was changed from that in Example 1-1 as follows.

[0051] For pressure control, the servo motor holding the upper platen was used to drive the device, and when a specified load (A) of 100N was detected, the vacuum suction was stopped and air injection was started. While continuing the air injection, the upper platen was lowered and the descent of the upper platen was stopped at a stop load (B) of 2000 N. This allowed the resin to be spread over the first main surface of the wafer while releasing the upper platen from holding the second main surface of the wafer. Next, while continuing the air injection, the upper platen was raised by a predetermined distance L and then stopped, after which the air injection was stopped. As a result, a gap was formed between the wafer and the upper platen. The resin was irradiated with ultraviolet light to harden it and create a flattened resin layer. (There was a gap between the wafer and the upper platen when ultraviolet light was irradiated.) Here, taking into consideration the influence of transfer due to the gap between the wafer and the upper platen, three examples were carried out in which the above-mentioned predetermined distance L was set to 2 μm (Example 2-1), 5 μm (Example 2-2), and 10 μm (Example 2-3). A UV-LED with a wavelength of 365 nm was used as the light source for curing the resin.

[0052] (Grinding) <Comparative Example 1> In Comparative Example 1, a P-type Si single crystal wafer having a diameter of 300 mm similar to that used in Example 1-1 was prepared, and this wafer was subjected to a grinding process under the following conditions.

[0053] <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 produced composites were subjected to a grinding process under the following conditions.

[0054] ◇Grinding conditions The grinding process was performed using Disco's DFG8360. The grinding wheel used was one bonded with diamond abrasive grains. The grinding method thereafter differs between <Comparative Example 1> and the others (<Comparative Example 2>, <Examples 1-1 to 1-4>, <Examples 2-1 to 2-3>), and will therefore be described separately.

[0055] <Comparative Example 1> First grinding conditions (back surface (second main surface) grinding) The front surface (first main surface) of the wafer was vacuum-attached to the grinding stage, and the back surface (second main surface) was ground (without a planarizing resin layer).

[0056] Second grinding conditions (surface (first main surface) grinding) The first ground surface (ground second main surface) was vacuum-adsorbed onto the grinding stage, and the surface (first main surface) was ground. By adjusting the axis angle of the chuck table, the wafer thickness variation was adjusted to 1 μm or less.

[0057] <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 coated side (flattened resin layer) of the composite was vacuum-adsorbed, and the back side (second main surface) was ground. After grinding, the flattening resin layer was peeled off.

[0058] Second grinding conditions (surface (first main surface) grinding) The first ground surface (ground second main surface) was vacuum-adsorbed onto the grinding stage, and the surface (first main surface) was ground. By adjusting the axis angle of the chuck table, the wafer thickness variation was adjusted to 1 μm or less.

[0059] (Mirror polishing) The front and back surfaces (ground first and second main surfaces) of each wafer that had been ground as described above were subjected to mirror polishing.

[0060] [Measurement results] The warp and nanotopography (NT) of each wafer after mirror polishing were measured as follows.

[0061] The Warp and NT were measured using an optical interference type flatness / NT measuring device (KLA: WaferSight2+). As an index for NT, SQMM 2mm x 2mm was used. The results are shown in Table 1 below.

[0062] [Table 1]

[0063] In Comparative Example 1, grinding was performed without forming a flattening resin layer, and therefore both Warp and NT were defective.

[0064] In Comparative Example 2, the NT was good by forming a planarizing resin layer and then grinding, but because the resin continued to be spread onto the first main surface of the wafer while maintaining its hold by the upper platen, the shape of the platen was transferred, resulting in a Warp failure.

[0065] On the other hand, in Examples 1-1, 1-2, 1-3, and 1-4, while air was being injected, the resin was spread over the first main surface of the wafer with the upper platen released from its holding position, and the resin was hardened with the upper platen and the wafer spaced apart to form a planarized resin layer. As a result, the transfer of the platen shape was mitigated, and warp was improved compared to Comparative Example 2.

[0066] 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 ensured between the wafer and the upper platen when air injection was stopped, and thus Warp was further improved.

[0067] On the other hand, in Examples 2-1, 2-2, and 2-3, while air was being injected, the resin was spread over the first main surface of the wafer with the upper platen released from its holding position, and the resin was hardened with the upper platen and the wafer spaced apart to form a planarized resin layer. As a result, the transfer of the platen shape was mitigated, and warp was improved compared to Comparative Example 2.

[0068] In particular, in Examples 2-2 and 2-3, in which the upper platen was retracted by a distance of 5 μm or more during air injection, a sufficient gap was secured between the wafer and the upper platen when air injection was stopped, further improving Warp.

[0069] From the above results, it can be seen that when forming the planarizing resin layer, the resin was spread over the first main surface of the wafer while the upper platen was released from its holding state while air was injected, and the resin was hardened while the upper platen and the wafer were separated to form the planarizing resin layer, thereby preventing the transfer of the platen shape.

[0070] Furthermore, when the upper platen is placed on standby to separate the upper platen from the wafer, it is more desirable to set the load at the time when the air injection is stopped to 500 N or less.

[0071] Also, from the viewpoint of shortening the processing time, it is better to retract the upper platen during air injection, and more preferably, the retraction distance of the upper platen should be 5 μm or more.

[0072] The present invention is not limited to the above-described embodiment. The above-described embodiment is merely an example, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and exhibits similar effects is included in the technical scope of the present invention. [Explanation of symbols]

[0073] 1...wafer, 1A...first main surface, 1B...second main surface, 1C...ground second main surface, 1D...ground first main surface, 2...holding means (upper platen), 2a...through hole, 2b...gap, 3...lower platen, 4...light-transmitting film, 5...resin, 6...flattening resin layer, 10...composite, 20...grinding stage, 30...grinding wheel.

Claims

1. A method for manufacturing a wafer, comprising the steps of: providing a wafer having a first major surface and a second major surface opposite the first major surface; holding the second main surface of the wafer with a holding means; disposing a resin in a plastic state facing the first main surface of the wafer; pressing the wafer with the holding means to bring the first main surface of the wafer into contact with the resin; While spreading the resin on the first main surface of the wafer, air is injected from the holding means between the holding means and the second main surface, thereby spreading the resin on the first main surface of the wafer in a state where the second main surface of the wafer is released from the holding means; forming a gap between the wafer and the holding means while performing the air injection, thereby separating the wafer from the holding means; After the wafer is separated from the holding means, the resin is cured to form a planarized resin layer, thereby obtaining a composite including the wafer and the planarized resin layer in contact with the first main surface of the wafer; adsorbing and holding the composite using 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; 4. 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.

2. 2. The method for manufacturing a wafer according to claim 1, wherein the gap between the wafer and the holding means is formed by retracting the holding means at the separation between the wafer and the holding means.

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