Substrate processing apparatus and substrate processing method

Abstract

The substrate processing apparatus includes: a holding unit having a circular center region and an annular outer region disposed on an outer side of the center region on an adsorption surface for adsorbing a substrate; a suction pressure generation unit for generating suction pressure independently from each other in the central region, an outer first region set at one location in the circumferential direction of the outer region, and an outer second region set at a location different from the outer first region in the circumferential direction of the outer region; and a control unit that controls the suction pressure generation unit. The control unit selects, in accordance with the warped state of the substrate, between an outer central mode in which the suction pressure is generated in the order of the outer first region and the central region, and a central outer mode in which the suction pressure is generated in the order of the central region and the outer first region.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing device and a substrate processing method. Background Art

[0002] Patent document 1 discloses a bonding device, which includes an upper holding disk for sucking an upper substrate from above and a lower holding disk for sucking a lower substrate from below, and the bonding device bonds two substrates facing each other. During the bonding of the substrates, the bonding device presses the center of the substrate of the upper holding disk to make it contact with the center of the substrate of the lower holding disk, and uses intermolecular force to bond the center of the two substrates to each other, and the bonding area expands from the center to the periphery.

[0003] In the substrate processing apparatus that sucks and holds the substrate as described above, if the holding plate simply sucks the substrate, there is a possibility that the substrate processing is performed in a state where residual stress on the substrate is large due to warping of the substrate or the like.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2015-095579 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] The present disclosure provides a technology capable of improving the distribution of residual stress of a substrate and appropriately adsorbing the substrate.

[0009] Solutions for solving problems

[0010] According to one embodiment of the present disclosure, there is provided a substrate processing device, which comprises: a holding portion, wherein an adsorption surface of the holding portion for adsorbing a substrate has a circular central area, and an annular outer area arranged at a position closer to the outside than the central area; an adsorption pressure generating portion, which generates adsorption pressure independently for the central area, an outer first area set at a position in the circumferential direction of the outer area, and an outer second area set at a position different from the outer first area in the circumferential direction of the outer area; and a control portion, which controls the adsorption pressure generating portion, wherein the control portion selects between an outer central mode and a central outer mode according to a warping state of the substrate, the outer central mode being a mode in which adsorption pressure is generated in the order of the outer first area and the central area, and the central outer mode being a mode in which adsorption pressure is generated in the order of the central area and the outer first area.

[0011] Effects of the Invention

[0012] According to one embodiment, the distribution of residual stress of the substrate can be improved to appropriately adsorb the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a top view showing a bonding device according to one embodiment of the present disclosure.

[0014] Figure 2 yes Figure 1 A side view of a joining device.

[0015] Figure 3 It is a side view showing an example of the first substrate and the second substrate.

[0016] Figure 4 1 is a flowchart showing a bonding method of the bonding device.

[0017] Figure 5 It is a plan view showing an example of the joining module according to the first embodiment.

[0018] Figure 6 yes Figure 5 Side view of the engagement module.

[0019] Figure 7 It is a cross-sectional view showing an example of the upper holding plate and the lower holding plate.

[0020] Figure 8 It is shown Figure 4 Flowchart showing the details of step S109.

[0021] Fig. 9 (A) shows Figure 8 A side view of an example of the operation in step S112. Fig. 9 (B) shows the following Fig. 9 (A) A side view of the action after. Fig. 9 (C) shows that Fig. 9 (B) A side view of the action afterward.

[0022] Fig.10 (A) shows Figure 8 A cross-sectional view of an example of the operation in step S113. Fig.10 (B) shows Figure 8 A cross-sectional view of an example of the operation in step S114. Fig.10 (C) shows that Fig.10 (B) A cross-sectional view of the action after.

[0023] Fig.11 It is a top view showing an example of the adsorption surface of the lower holding disk.

[0024] Fig.12(A) is a perspective view showing an example of warpage of the lower wafer. Fig.12 (B) is an explanatory diagram showing the relationship between the adsorption surface and the lower wafer in the Y-axis direction. Fig.12 (C) is an explanatory diagram showing the relationship between the adsorption surface and the lower wafer in the X-axis direction.

[0025] Fig.13 It is an explanatory diagram showing the relationship between the warpage of the lower wafer in the X-axis direction and the warpage in the Y-axis direction.

[0026] Fig.14 (A) is a plan view showing an example of the suction operation of the lower wafer. Fig.14 (B) shows the following Fig.14 (A) is a top view of the action after. Fig.14 (C) shows that Fig.14 (B) is a top view of the action after. Fig.14 (D) shows the Fig.14 (C) A top view of the action after. Fig.14 (E) shows the Fig.14 (D) is a top view of the action after. Fig.14 (F) shows the Fig.14 (E) is a top view of the action after.

[0027] Fig.15 : is a table showing examples of the suction operation according to the warpage state of the lower wafer.

[0028] Fig.16 It is a side view of the joining module involved in the second embodiment.

[0029] Fig.17 It is an explanatory diagram showing the relationship between the warpage in the X-axis direction and the warpage in the Y-axis direction of the lower wafer and the curved surface of the suction surface. DETAILED DESCRIPTION

[0030] Hereinafter, the mode for implementing the present disclosure will be described with reference to the drawings. In each of the drawings, the same reference numerals are given to the same components, and duplicate descriptions may be omitted.

[0031] As a substrate processing apparatus disclosed in the present invention, a typical Figure 1 and Figure 2The bonding device 1 shown in the figure is described. In addition, the substrate processing device disclosed in the present invention is not limited to the bonding device 1, as long as it is a device that has a holding portion for holding a substrate and processes the substrate held by the holding portion. As examples of other substrate processing devices, an exposure device, a temperature control device, etc. can be cited. The exposure device is a device that holds a substrate using a holding portion and transfers a mask pattern onto the substrate. The temperature control device is a device that holds a substrate using a holding portion and adjusts the temperature of the substrate.

[0032] like Figure 3 As shown, the bonding device 1 bonds the first substrate W1 and the second substrate W2 to produce a bonded substrate T. At least one of the first substrate W1 and the second substrate W2 is a substrate having a plurality of electronic circuits formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. One of the first substrate W1 and the second substrate W2 may also be a bare wafer without an electronic circuit formed thereon. There is no particular limitation on the compound semiconductor wafer, and it may be, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0033] The first substrate W1 and the second substrate W2 are formed into circular plates of substantially the same shape (same diameter). The bonding device 1 arranges the second substrate W2 on the negative side of the Z-axis (vertically lower side) of the first substrate W1, and bonds the first substrate W1 to the second substrate W2. Therefore, hereinafter, the first substrate W1 is sometimes referred to as the "upper wafer W1", the second substrate W2 is sometimes referred to as the "lower wafer W2", and the bonded substrate T is sometimes referred to as the "bonded wafer T". In addition, hereinafter, the plate surface of the upper wafer W1 on the side to be bonded to the lower wafer W2 is referred to as the "bonding surface W1j", and the plate surface on the side opposite to the bonding surface W1j is referred to as the "non-bonding surface W1n". In addition, the plate surface of the lower wafer W2 on the side to be bonded to the upper wafer W1 is referred to as the "bonding surface W2j", and the plate surface on the side opposite to the bonding surface W2j is referred to as the "non-bonding surface W2n".

[0034] like Figure 1 As shown, the bonding apparatus 1 includes a loading / unloading station 2 and a processing station 3 in this order toward the positive direction of the X axis. The loading / unloading station 2 and the processing station 3 are connected as one body.

[0035] The loading and unloading station 2 includes a loading table 10 and a conveying area 20. The loading table 10 includes a plurality of loading plates 11. Boxes CS1, CS2, and CS3 for accommodating a plurality of (e.g., 25) substrates in a horizontal state are placed on the respective loading plates 11. Box CS1 is a box for accommodating an upper wafer W1, box CS2 is a box for accommodating a lower wafer W2, and box CS3 is a box for accommodating a bonding wafer T. In addition, the upper wafer W1 and the lower wafer W2 are accommodated in the boxes CS1 and CS2 in an aligned orientation with the bonding surfaces W1j and W2j being set as the upper surfaces.

[0036] The transport area 20 is arranged adjacent to the X-axis positive direction side of the mounting table 10, and includes a transport path 21 extending in the Y-axis direction and a transport device 22 that can move along the transport path 21. The transport device 22 can also move in the X-axis direction and can also rotate around the Z-axis to transport the upper wafer W1, the lower wafer W2, and the bonded wafer T between the cassettes CS1 to CS3 mounted on the mounting table 10 and the third processing block PB3 of the processing station 3 described later.

[0037] The processing station 3 includes, for example, three processing blocks PB1, PB2, and PB3. The first processing block PB1 is provided on the back side of the processing station 3 ( Figure 1 The second processing block PB2 is arranged on the front side of the processing station 3 ( Figure 1 The third processing block PB3 is set on the side of the processing station 3 close to the loading and unloading station 2 ( Figure 1 negative side of the X-axis).

[0038] In addition, the processing station 3 has a transfer area 60 having a transfer device 61 in an area surrounded by the first processing block PB1 to the third processing block PB3. For example, the transfer device 61 has a transfer arm that can move freely in the vertical direction, the horizontal direction, and around the vertical axis. The transfer device 61 moves in the transfer area 60 to transfer the upper wafer W1, the lower wafer W2, and the bonded wafer T to the devices in the first processing block PB1, the second processing block PB2, and the third processing block PB3 adjacent to the transfer area 60.

[0039] The first processing block PB1 includes, for example, a surface modification device 33 and a surface hydrophilization device 34. The surface modification device 33 modifies the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2. The surface hydrophilization device 34 hydrophilizes the modified bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2.

[0040] For example, the surface modification device 33 cuts the bonds of SiO2 in the bonding surfaces W1j and W2j to form dangling bonds of Si, so that hydrophilization can be performed later. In the surface modification device 33, for example, oxygen as a processing gas is excited to plasma under a reduced pressure atmosphere, thereby ionizing. Moreover, by irradiating the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 with oxygen ions, the bonding surfaces W1j and W2j are modified by plasma treatment. The processing gas is not limited to oxygen, but can also be nitrogen or the like.

[0041] The surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 and W2j of the lower wafer W2 by using a hydrophilization treatment liquid such as pure water. The surface hydrophilization device 34 also has the function of cleaning the bonding surfaces W1j and W2j. In the surface hydrophilization device 34, for example, while rotating the upper wafer W1 or the lower wafer W2 held on the rotating holding disk, pure water is supplied to the upper wafer W1 or the lower wafer W2. As a result, pure water diffuses on the bonding surfaces W1j and W2j, OH groups are attached to the dangling bonds of Si, and the bonding surfaces W1j and W2j are hydrophilized.

[0042] like Figure 2 As shown, the second processing block PB2, for example, has a bonding module 41, a first temperature regulating device 42, and a second temperature regulating device 43. The bonding module 41 bonds the upper wafer W1 and the lower wafer W2 after being hydrophilized to produce a bonded wafer T. Before producing the bonded wafer T, the first temperature regulating device 42 adjusts the temperature distribution of the upper wafer W1. Before producing the bonded wafer T, the second temperature regulating device 43 adjusts the temperature distribution of the lower wafer W2. In addition, in the present embodiment, the first temperature regulating device 42 and the second temperature regulating device 43 are provided separately from the bonding module 41, but may also be provided as a part of the bonding module 41.

[0043] The third processing block PB3 includes, for example, a first position adjustment device 51, a second position adjustment device 52, and conveying devices 53 and 54 in order from top to bottom. Figure 2 The configuration position shown. The first position adjustment device 51 adjusts the horizontal direction of the upper wafer W1, and also turns the upper wafer W1 upside down so that the bonding surface W1j of the upper wafer W1 faces downward. The second position adjustment device 52 adjusts the horizontal direction of the lower wafer W2. The conveying device 53 temporarily places the upper wafer W1. In addition, the conveying device 54 temporarily places the lower wafer W2 and the bonding wafer T.

[0044] Back to Figure 1 The bonding device 1 is provided with a control device (control unit) 90 for controlling each structure. The control device 90 is a control computer having a memory 92, an input / output interface (not shown), an electronic circuit, and one or more processors 91. The one or more processors 91 are one of a CPU, an ASIC, an FPGA, a circuit composed of a plurality of discrete semiconductors, etc., or a combination of a plurality of them, and are used to execute a program stored in the memory 92. The memory 92 includes a non-volatile memory and a volatile memory, and forms a storage unit of the control device 90.

[0045] Next, refer to Figure 4 The bonding method of this embodiment will be described. Figure 4The steps S101 to S109 shown are implemented under the control of the control device 90 .

[0046] In the bonding method, an operator or a transfer robot (not shown) places a cassette CS1 containing a plurality of upper wafers W1 , a cassette CS2 containing a plurality of lower wafers W2 , and an empty cassette CS3 on the mounting table 10 of the loading / unloading station 2 .

[0047] The bonding apparatus 1 takes out the upper wafer W1 in the cassette CS1 by the transfer device 22 and transfers it to the transfer device 53 of the third processing block PB3 of the processing station 3. Then, the bonding apparatus 1 takes out the upper wafer W1 from the transfer device 53 by the transfer device 61 and transfers it to the surface modification device 33 of the first processing block PB1.

[0048] Next, the bonding device 1 modifies the bonding surface W1j of the upper wafer W1 using the surface modification device 33 (step S101). The surface modification device 33 modifies the bonding surface W1j with the bonding surface W1j facing upward. Thereafter, the transport device 61 takes the upper wafer W1 out of the surface modification device 33 and transports it to the surface hydrophilization device 34.

[0049] Furthermore, the bonding device 1 hydrophilizes the bonding surface W1j of the upper wafer W1 using the surface hydrophilizing device 34 (step S102). The surface hydrophilizing device 34 hydrophilizes the bonding surface W1j with the bonding surface W1j facing upward. Thereafter, the transport device 61 takes out the upper wafer W1 from the surface hydrophilizing device 34 and transports it to the first position adjustment device 51 of the third processing block PB3.

[0050] The bonding device 1 uses the first position adjustment device 51 to adjust the horizontal direction of the upper wafer W1, and turns the upper wafer W1 upside down (step S103). As a result, the cut of the upper wafer W1 faces the specified direction, and the bonding surface W1j of the upper wafer W1 faces downward. After that, the conveying device 61 takes out the upper wafer W1 from the first position adjustment device 51 and conveys it to the first temperature adjustment device 42 of the second processing block PB2.

[0051] The bonding apparatus 1 adjusts the temperature of the upper wafer W1 using the first temperature adjustment device 42 (step S104 ). The temperature adjustment of the upper wafer W1 is performed with the bonding surface W1j of the upper wafer W1 facing downward. Then, the transfer device 61 takes the upper wafer W1 out of the first temperature adjustment device 42 and transfers it to the bonding module 41 .

[0052] The bonding device 1 performs the above-mentioned processing on the lower wafer W2 in parallel with the processing on the upper wafer W1. First, the bonding device 1 takes out the lower wafer W2 in the cassette CS2 by the conveying device 22 and conveys it to the conveying device 54 of the third processing block PB3 of the processing station 3. Then, the conveying device 61 takes out the lower wafer W2 from the conveying device 54 and conveys it to the surface modification device 33 of the first processing block PB1.

[0053] The bonding device 1 modifies the bonding surface W2j of the lower wafer W2 using the surface modification device 33 (step S105 ). The surface modification device 33 modifies the bonding surface W2j with the bonding surface W2j facing upward. Then, the transport device 61 takes the lower wafer W2 out of the surface modification device 33 and transports it to the surface hydrophilization device 34 .

[0054] The bonding device 1 hydrophilizes the bonding surface W2j of the lower wafer W2 using the surface hydrophilizing device 34 (step S106). The surface hydrophilizing device 34 hydrophilizes the bonding surface W2j with the bonding surface W2j facing upward. Afterwards, the transport device 61 takes out the lower wafer W2 from the surface hydrophilizing device 34 and transports it to the second position adjustment device 52 of the third processing block PB3.

[0055] The bonding device 1 adjusts the horizontal orientation of the lower wafer W2 using the second position adjustment device 52 (step S107). As a result, the cut of the lower wafer W2 is oriented to a predetermined orientation. Afterwards, the transport device 61 takes the lower wafer W2 out of the second position adjustment device 52 and transports it to the second temperature adjustment device 43 of the second processing block PB2.

[0056] The bonding apparatus 1 adjusts the temperature of the lower wafer W2 using the second temperature adjustment device 43 (step S108 ). The temperature adjustment of the lower wafer W2 is performed with the bonding surface W2j of the lower wafer W2 facing upward. Afterwards, the transport device 61 takes the lower wafer W2 out of the second temperature adjustment device 43 and transports it to the bonding module 41 .

[0057] Then, the bonding apparatus 1 bonds the upper wafer W1 and the lower wafer W2 in the bonding module 41 to produce a bonded wafer T (step S109 ). After producing the bonded wafer T, the transport device 61 takes out the bonded wafer T from the bonding module 41 and transports it to the transfer device 54 of the third processing block PB3 .

[0058] Finally, the bonding apparatus 1 takes out the bonding wafer T from the conveyor 54 by the transfer device 22 and transfers it to the cassette CS3 on the mounting table 10. Thus, a series of processes are completed.

[0059] [First embodiment]

[0060] Next, refer to Figure 5 to Figure 7An example of the joining module 41 according to the first embodiment will be described. Figure 5 As shown, the bonding module 41 has a processing container 210 that can be sealed inside. A loading and unloading port 211 is formed on the side of the processing container 210 on the side close to the transfer area 60, and an opening and closing gate 212 is provided at the loading and unloading port 211. The upper wafer W1, the lower wafer W2, and the bonding wafer T are loaded and unloaded through the loading and unloading port 211.

[0061] like Figure 6 As shown, an upper holding plate 230 and a lower holding plate 231 are provided inside the processing container 210. The upper holding plate 230 is used to hold the upper wafer W1 from above the upper wafer W1 with its bonding surface W1j facing downward. In addition, the lower holding plate 231 is provided below the upper holding plate 230 and is used to hold the lower wafer W2 from below the lower wafer W2 with its bonding surface W2j facing upward.

[0062] The upper holding disk 230 is supported by a support member 280 provided on the top surface of the processing container 210 . On the other hand, the lower holding disk 231 is supported by a first lower holding disk moving unit 291 provided below the lower holding disk 231 .

[0063] The first lower holding plate moving portion 291 moves the lower holding plate 231 in the horizontal direction (Y-axis direction) as described later. The first lower holding plate moving portion 291 is configured to move the lower holding plate 231 in the vertical direction and to be rotatable about the vertical axis.

[0064] The first lower holding plate moving part 291 is attached to a pair of guide rails 295 provided on the lower surface side of the first lower holding plate moving part 291 and extending in the horizontal direction (Y-axis direction). The first lower holding plate moving part 291 is configured to be movable along the guide rails 295. The guide rails 295 are provided on the second lower holding plate moving part 296.

[0065] The second lower holding plate moving part 296 is attached to a pair of guide rails 297 provided on the lower surface side of the second lower holding plate moving part 296 and extending in the horizontal direction (X-axis direction). The second lower holding plate moving part 296 is configured to be movable along the guide rails 297. In addition, the pair of guide rails 297 is provided on a mounting table 298 provided on the bottom surface of the processing container 210.

[0066] The first lower holding disk moving part 291 and the second lower holding disk moving part 296 constitute a moving mechanism 290. The moving mechanism 290 moves the lower holding disk 231 relative to the upper holding disk 230. The moving mechanism 290 moves the lower holding disk 231 between the substrate taking-over position and the bonding position.

[0067] The substrate handover position is a position where the upper holding plate 230 receives the upper wafer W1 from the conveying device 61, and the lower holding plate 231 receives the lower wafer W2 from the conveying device 61, and the lower holding plate 231 hands over the bonded wafer T to the conveying device 61. The substrate handover position is a position where the bonded wafer T produced by the nth (n is a natural number greater than 1) bonding is continuously carried out, and the upper wafer W1 and the lower wafer W2 to be bonded by the n+1th bonding are carried in. The substrate handover position is, for example Figure 5 and Figure 6 Position shown.

[0068] The transfer device 61 enters directly under the upper holding disk 230 when transferring the upper wafer W1 to the upper holding disk 230. In addition, the transfer device 61 enters directly above the lower holding disk 231 when receiving the bonded wafer T from the lower holding disk 231 and transferring the lower wafer W2 to the lower holding disk 231. The upper holding disk 230 and the lower holding disk 231 are offset in the lateral direction, and the interval between the upper holding disk 230 and the lower holding disk 231 in the vertical direction is also large, so that the transfer device 61 can easily enter.

[0069] On the other hand, the bonding position is a position (opposing position) where the upper wafer W1 and the lower wafer W2 face each other with a predetermined distance therebetween. Figure 7 At the bonding position, the gap between the upper wafer W1 and the lower wafer W2 in the vertical direction is narrower than at the substrate handover position. In addition, at the bonding position, unlike at the substrate handover position, the upper wafer W1 and the lower wafer W2 overlap when viewed in the vertical direction.

[0070] The moving mechanism 290 moves the relative position of the upper holding disk 230 and the lower holding disk 231 in the horizontal direction (two directions of the X-axis direction and the Y-axis direction) and the vertical direction. In addition, the moving mechanism 290 moves the lower holding disk 231 in the present embodiment, but it can also move either the lower holding disk 231 or the upper holding disk 230, or both. In addition, the moving mechanism 290 can also rotate the upper holding disk 230 or the lower holding disk 231 around the vertical axis.

[0071] like Figure 7 As shown, the upper holding disk 230 is divided into a plurality of (for example, three) regions 230a, 230b, and 230c along the radial direction of the upper holding disk 230. These regions 230a, 230b, and 230c are arranged in the order of regions 230a, 230b, and 230c from the center toward the outer edge of the upper holding disk 230. The region 230a is formed to be a perfect circle in a plan view, and the regions 230b and 230c are formed to be annular in a plan view.

[0072] Suction pipes 240a, 240b, 240c are independently provided in each region 230a, 230b, 230c. Different vacuum pumps 241a, 241b, 241c are connected to each suction pipe 240a, 240b, 240c. The upper holding plate 230 can vacuum absorb the upper wafer W1 in each region 230a, 230b, 230c.

[0073] A plurality of holding pins 245 that can be raised and lowered in the vertical direction are provided on the upper holding plate 230. The plurality of holding pins 245 are connected to a vacuum pump 246, and the upper wafer W1 is vacuum-absorbed by the operation of the vacuum pump 246. The upper wafer W1 is vacuum-absorbed to the lower ends of the plurality of holding pins 245. An annular absorption pad may also be used instead of the plurality of holding pins 245.

[0074] The plurality of holding pins 245 are lowered by a driving unit (not shown) to protrude from the suction surface of the upper holding disk 230. In this state, the plurality of holding pins 245 vacuum suction the upper wafer W1 to receive the upper wafer W1 from the transfer device 61. Thereafter, the plurality of holding pins 245 are raised to bring the upper wafer W1 into contact with the suction surface of the upper holding disk 230. Next, the upper holding disk 230 vacuum suctions the upper wafer W1 horizontally in each region 230a, 230b, 230c by the operation of the vacuum pumps 241a, 241b, 241c.

[0075] The upper holding plate 230 has a through hole 243 at the center thereof that vertically penetrates the upper holding plate 230. The pusher 250 is inserted through the through hole 243. The pusher 250 presses the center of the upper wafer W1 spaced apart from the lower wafer W2 to bring the upper wafer W1 into contact with the lower wafer W2.

[0076] The pusher 250 includes a pusher pin 251 and an outer cylinder 252 serving as a lifting guide for the pusher pin 251. The pusher pin 251 is inserted through the through hole 243 by a drive unit (not shown) having a built-in motor, for example, and protrudes from the suction surface of the upper holding plate 230 to press the center of the upper wafer W1.

[0077] In addition, the lower holding plate 231 also has a plurality of partitioned areas on the suction surface 300 for suctioning the lower wafer W2. The structure of the suction surface 300 of the lower holding plate 231 will be described in detail later.

[0078] The lower holding plate 231 is provided with a plurality of (for example, three) holding pins 265 that can be raised and lowered in the vertical direction. The lower wafer W2 is placed on the upper ends of the plurality of holding pins 265. Alternatively, the lower wafer W2 may be vacuum-adsorbed on the upper ends of the plurality of holding pins 265.

[0079] The plurality of holding pins 265 protrude from the suction surface 300 of the lower holding disk 231 by rising. In this state, the plurality of holding pins 265 receive the lower wafer W2 from the transfer device 61. Thereafter, the plurality of holding pins 265 descend, and the lower wafer W2 contacts the suction surface 300 of the lower holding disk 231. Next, the lower holding disk 231 vacuum-suctions the lower wafer W2 horizontally in a plurality of regions of the suction surface 300.

[0080] Next, refer to Figure 8 to Figure 10 right Figure 4 The process of manufacturing the bonded wafer T in step S109 is described in detail. Figure 8 As shown, the control device 90 uses the transport device 61 to load the upper wafer W1 and the lower wafer W2 into the bonding module 41 (step S111). The relative positions of the upper holding plate 230 and the lower holding plate 231 after loading are Figure 6 and Figure 7 The substrate interface position is shown.

[0081] Next, the control device 90 moves the relative position of the upper holding plate 230 and the lower holding plate 231 from the substrate transfer position to the substrate transfer position through the moving mechanism 290. Figure 7 In step S112, the control device 90 Fig. 9 As shown, the first camera S1 and the second camera S2 are used to align the positions of the upper wafer W1 and the lower wafer W2.

[0082] The first camera S1 is fixed to the upper holding plate 230 and captures the lower wafer W2 held by the lower holding plate 231. A plurality of reference points P21 to P23 are pre-formed on the bonding surface W2j of the lower wafer W2. As the reference points P21 to P23, patterns of electronic circuits or the like are used. The number of reference points can be set arbitrarily.

[0083] On the other hand, the second camera S2 is fixed to the lower holding plate 231 and photographs the upper wafer W1 held on the upper holding plate 230. A plurality of reference points P11 to P13 are pre-formed on the bonding surface W1j of the upper wafer W1. As the reference points P11 to P13, patterns of electronic circuits or the like are used. The number of reference points can be set arbitrarily.

[0084] like Fig. 9As shown in (A), the joint module 41 adjusts the relative horizontal positions of the first camera S1 and the second camera S2 through the moving mechanism 290. Specifically, the moving mechanism 290 moves the lower holding plate 231 in the horizontal direction so that the second camera S2 is located approximately directly below the first camera S1. In addition, the first camera S1 and the second camera S2 shoot a common target X, and the moving mechanism 290 fine-tunes the horizontal position of the second camera S2 so that the horizontal positions of the first camera S1 and the second camera S2 are consistent.

[0085] Then, if Fig. 9 As shown in (B), the moving mechanism 290 moves the lower holding plate 231 vertically upward and then adjusts the horizontal positions of the upper holding plate 230 and the lower holding plate 231. Specifically, while the moving mechanism 290 moves the lower holding plate 231 in the horizontal direction, the first camera S1 sequentially photographs the reference points P21 to P23 of the lower wafer W2, and the second camera S2 sequentially photographs the reference points P11 to P13 of the upper wafer W1. In addition, Fig. 9 (B) shows a situation where the first camera S1 photographs the reference point P21 of the lower wafer W2 , and the second camera S2 photographs the reference point P11 of the upper wafer W1 .

[0086] The first camera S1 and the second camera S2 send the captured image data to the control device 90. The control device 90 controls the moving mechanism 290 to adjust the horizontal position of the lower holding plate 231 based on the image data captured by the first camera S1 and the image data captured by the second camera S2, so that the reference points P11 to P13 of the upper wafer W1 coincide with the reference points P21 to P23 of the lower wafer W2 when viewed in the vertical direction.

[0087] Then, if Fig. 9 As shown in (C), the moving mechanism 290 moves the lower holding plate 231 vertically upward. As a result, the gap G (refer to Figure 7 ) becomes a predetermined distance, for example, 80 μm to 200 μm. The gap G is adjusted using the first displacement gauge S3 and the second displacement gauge S4.

[0088] The first displacement meter S3 is fixed to the upper holding plate 230, and is used to measure the thickness of the lower wafer W2 held on the lower holding plate 231. The first displacement meter S3 measures the thickness of the lower wafer W2, for example, by irradiating light to the lower wafer W2 and receiving reflected light reflected by the upper and lower surfaces of the lower wafer W2. The thickness measurement is implemented, for example, when the moving mechanism 290 moves the lower holding plate 231 in the horizontal direction. The measurement method of the first displacement meter S3 is, for example, a confocal method, a spectroscopic interference method, or a triangulation ranging method. The light source of the first displacement meter S3 is an LED or a laser.

[0089] On the other hand, the second displacement meter S4 is fixed to the lower holding plate 231, and is used to measure the thickness of the upper wafer W1 held on the upper holding plate 230. The second displacement meter S4 measures the thickness of the upper wafer W1, for example, by irradiating light to the upper wafer W1 and receiving reflected light reflected by the upper and lower surfaces of the upper wafer W1. The thickness measurement is implemented, for example, when the moving mechanism 290 moves the lower holding plate 231 in the horizontal direction. The measurement method of the second displacement meter S4 is, for example, a confocal method, a spectroscopic interference method, or a triangulation ranging method. The light source of the second displacement meter S4 is an LED or a laser.

[0090] Each first displacement meter S3 and each second displacement meter S4 transmits the measured information to the control device 90. The control device 90 controls the moving mechanism 290 to adjust the vertical position of the lower holding plate 231 based on the measured information measured by each first displacement meter S3 and the measured information measured by each second displacement meter S4 so that the gap G becomes a set value.

[0091] Next, the vacuum pump 241a is stopped. Fig.10 As shown in (A), the vacuum adsorption of the upper wafer W1 in the area 230a is released. Then, the push pin 251 of the push unit 250 descends to press the center of the upper wafer W1, so that the upper wafer W1 and the lower wafer W2 are in contact (step S113). As a result, the centers of the upper wafer W1 and the lower wafer W2 are bonded to each other.

[0092] Since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, first, van der Waals force (intermolecular force) is generated between the bonding surfaces W1j and W2j, so that the bonding surfaces W1j and W2j are bonded to each other. In addition, since the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized, the hydrophilic groups (such as OH groups) are hydrogen bonded, so that the bonding surfaces W1j and W2j are firmly bonded to each other.

[0093] Next, the control device 90 stops the operation of the vacuum pump 241b, such as Fig.11As shown in (B), the vacuum adsorption of the upper wafer W1 in the area 230b is released. Then, the control device 90 stops the operation of the vacuum pump 241c. Fig.11 As shown in (C), the vacuum suction of the upper wafer W1 in the region 230c is released.

[0094] In this way, the vacuum adsorption of the upper wafer W1 is released in stages from the center of the upper wafer W1 toward the periphery, so that the upper wafer W1 falls in stages and abuts against the lower wafer W2. Moreover, the bonding of the upper wafer W1 and the lower wafer W2 progresses sequentially from the center to the periphery (step S114). As a result, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 are in full contact, and the upper wafer W1 and the lower wafer W2 are bonded to obtain a bonded wafer T. Afterwards, the bonding device 1 causes the push pin 251 to rise to its original position.

[0095] After the bonded wafer T is formed, the control device 90 uses the moving mechanism 290 to adjust the relative position of the upper holding plate 230 and the lower holding plate 231 from Figure 8 The engagement position shown moves to Figure 6 and Figure 7 For example, the moving mechanism 290 first lowers the lower holding plate 231 to increase the vertical distance between the lower holding plate 231 and the upper holding plate 230. Then, the moving mechanism 290 moves the lower holding plate 231 laterally to offset the lower holding plate 231 from the upper holding plate 230 in the horizontal direction.

[0096] Afterwards, the control device 90 carries out the bonded wafer T relative to the bonding module 41 through the conveying device 61 (step S116). Specifically, first, the lower holding plate 231 releases the holding of the bonded wafer T. Then, the plurality of holding pins 265 rise to transfer the bonded wafer T to the conveying device 61. Thereafter, the plurality of holding pins 265 descend to their original positions.

[0097] Next, refer to Fig.11 The structure of the suction surface 300 of the lower holding plate 231 is described below. In addition, the technology disclosed in the present invention can also be applied to the suction surface of the upper holding plate 230. Fig.11 In FIG. 1 , the shaded area is an area where suction pressure is generated. The suction surface 300 of the lower holding plate 231 has a plurality of areas where suction pressure is generated independently.

[0098] For example, the adsorption surface 300 is divided into a central area A, a middle area B, and an outer area C by annular ribs 301, ribs 302, and ribs 303. The central area A, the middle area B, and the outer area C are arranged concentrically in the order of the central area A, the middle area B, and the outer area C from the center of the adsorption surface 300 toward the outer edge. Specifically, the central area A is formed into a perfect circle. The middle area B is formed into an annular shape at the outer adjacent position of the central area A. The outer area C is formed into an annular shape at the outer adjacent position of the middle area B. In addition, the adsorption surface 300 may not include the middle area B, but the outer adjacent position of the central area A is the outer area C. On the contrary, the adsorption surface 300 may also have a plurality of annular middle areas B between the central area A and the outer area C.

[0099] The middle region B is divided into eight arc-shaped areas (small areas: one part) by a plurality of radial ribs 305. Similarly, the outer region C is divided into eight arc-shaped areas by each rib 305. The number of divisions of the middle region B and the number of divisions of the outer region C may be the same or different.

[0100] The central area A, the 8 zones of the middle area B, and the 8 zones of the outer area C are configured to be able to independently attract the lower wafer W2. Among them, the lower holding plate 231 involved in this embodiment is connected to 10 attraction mechanisms 311 for a total of 17 zones, and the attraction surface 300 is attracted in each of the zones of the 10 channels. In other words, the attraction surface 300 has a zone attracted by the same attraction mechanism 311 in a total of 17 zones.

[0101] Specifically, one zone (ch1) is set for the central region A and connected to a predetermined suction mechanism 311. On the other hand, three zones (ch2 to ch4) are set for the middle region B. Fig.11 The two adjacent areas on the left and right of the center are ch2. Fig.11 The two adjacent zones in the upper and lower directions (in the middle region B) are ch3. In addition, the four zones sandwiched between the zones of ch2 and ch3 in the middle region B are ch4. On the other hand, six zones (ch5 to ch10) are set for the outer region C. The zone in the positive direction of the X axis ( Fig.11 The area adjacent to the middle area B in the negative direction of the X axis ( Fig.11 The area adjacent to the middle area B in the negative direction of the Y axis ( Fig.11 The area adjacent to the middle area B in the positive direction of the Y axis ( Fig.11A region adjacent to the ch5 region and the ch7 region in the outer region C is ch8. Furthermore, a region sandwiched between the ch5 region and the ch7 region, and a region sandwiched between the ch6 region and the ch7 region in the outer region C is ch9. Similarly, a region sandwiched between the ch5 region and the ch8 region, and a region sandwiched between the ch6 region and the ch8 region in the outer region C is ch10.

[0102] On the X-axis line passing through the center of the adsorption surface 300, the zones ch5, ch2, ch1, ch2, and ch6 are arranged in this order from the positive direction of the X-axis toward the negative direction of the X-axis. On the Y-axis line passing through the center of the adsorption surface 300, the zones ch7, ch3, ch1, ch3, and ch8 are arranged in this order from the negative direction of the Y-axis toward the positive direction of the X-axis. In addition, the adsorption surface 300 can of course freely design the number and location of the channels in each zone.

[0103] The bonding module 41 is provided with an adsorption pressure generating unit 310 for independently generating adsorption pressure in each area of ​​the 10 channels of the adsorption surface 300. Each suction mechanism 311 of the adsorption pressure generating unit 310 has a suction line 312 connected to a specified area, and a suction pump 313, an opening and closing valve 314, and a pressure controller 315 are provided on the suction line 312. The adsorption pressure generating unit 310 is connected to the control device 90 so as to be communicable, and each suction mechanism 311 is operated under the control of the control device 90.

[0104] Each suction mechanism 311 generates adsorption pressure (negative pressure) in the area connected to the suction line 312 by, for example, operating the suction pump 313 of the specified suction line 312 and opening the on-off valve 314. The magnitude of the adsorption pressure is controlled by the pressure controller 315. In addition, each suction mechanism 311 releases the adsorption pressure of each area by closing the on-off valve 314 of the specified suction line 312 and introducing the atmosphere through the pressure controller 315.

[0105] Next, refer to Fig.12 To illustrate the warpage of the lower wafer W2. Fig.12 In (A), the black and white grayscale represents the height of the upper surface (joining surface W2j) of the lower wafer W2 relative to the suction surface 300 of the lower holding disk 231. The closer the color is to black, the lower the height of the upper surface of the lower wafer W2 is, and the smaller the gap between the upper surface of the lower wafer W2 and the suction surface 300 of the lower holding disk 231 is.

[0106] The warpage of the lower wafer W2 is measured by, for example, a warpage measuring device 5 (see FIG. Figure 1) is measured, and the control device 90 obtains information on the warpage state of the lower wafer W2 measured by the warpage measuring device 5. In addition, the warpage measuring device 5 can also be provided as a part of the bonding device 1. The bonding device 1 can also be configured to measure the warpage when the upper wafer W1 and the lower wafer W2 are moved in by using a plurality of displacement gauges (not shown) provided in the bonding module 41.

[0107] By the adsorption pressure generating unit 310 (refer to Fig.11 ) Before the suction surface 300 of the lower holding plate 231 generates suction pressure, sometimes the lower wafer W2 is Fig.12 The lower wafer W2 is warped as shown in (A). The warping of the lower wafer W2 is caused, for example, by stacking multiple films on a semiconductor substrate such as a silicon wafer. Each film is formed by a CVD (Chemical Vapor Deposition) method, an ALD (Atomic Layer Deposition) method, or a spin coating method. Due to the difference in thermal expansion during film formation, stress is applied to the lower wafer W2, causing the lower wafer W2 to warp.

[0108] The lower wafer W2 is mostly formed into a warp that is symmetrical across two orthogonal radial lines, that is, a line-symmetrical warp. This is because the Young's modulus, Poisson's ratio, and shear elastic coefficient of semiconductor substrates such as silicon wafers change in a period of 90°. When observed from a direction orthogonal to the adsorption surface 300 (Z-axis direction), the two orthogonal radial lines extend along a specific crystal orientation of the semiconductor substrate.

[0109] Furthermore, the bonding device 1 transfers the lower wafer W2 from the transfer device 61 to the lower holding plate 231 in such a manner that two straight lines in the radial direction orthogonal to each other are along the X-axis direction and the Y-axis direction of the lower holding plate 231. For example, by the second position adjustment device 52 (see Figure 2 ) to adjust the orientation (posture) of the lower wafer W2.

[0110] With the center of the lower wafer W2 as the base point, the warping of the lower wafer W2 includes a form in which the outer edge at the symmetrical position is warped in a direction close to the adsorption surface 300 (vertically lower side) and a form in which the outer edge at the symmetrical position is warped in a direction away from the adsorption surface 300 (vertically upper side). In the following, the warping of the outer edge of the lower wafer W2 toward the downward direction is referred to as negative warping (-warping) (first form), and the warping of the outer edge of the lower wafer W2 toward the upward direction is referred to as positive warping (+warping) (second form).

[0111] Here, a disc-shaped component such as the lower wafer W2 presents a saddle-shaped curved surface as follows: while being convexly curved from the two outer edges toward the center on the Y axis, it is concavely curved from the two outer edges toward the center on the X axis that is offset 90° along the circumferential direction. Therefore, the warping of the lower wafer W2 is in opposite directions on two straight lines in the orthogonal radial direction. That is, in the case of Fig.12 When negative warping occurs at the outer edge in the Y-axis direction as shown in (B), Fig.12 As shown in (C), positive warping occurs at the outer edge in the X-axis direction.

[0112] Next, refer to Fig.13 The effect of the warpage of the lower wafer W2 on the bonding surface W2j is described below. Fig.13 In the figure, for easy understanding, the cross section of the lower wafer W2 in the Y-axis direction is indicated by black, and the cross section of the lower wafer W2 in the X-axis direction is indicated by hollow, and the two are overlapped.

[0113] The bonding surface W2j, which is the upper surface of the lower wafer W2, expands and contracts along the warpage generated in the lower wafer W2 as a whole. Fig.13 In the cross section (in the Y-axis direction), the pair of outer edges descend downward in the vertical direction relative to the center, thereby extending the bonding surface W2j. On the other hand, in the radial direction (in the Y-axis direction) where positive warping occurs Fig.13 In the cross section (in the X-axis direction), a pair of outer edges rise upward in the vertical direction relative to the center, thereby shrinking the bonding surface W2j.

[0114] However, the expansion and contraction generated on the joint surface W2j may differ in the warping amount of the outer edge relative to the center in the X-axis direction and the warping amount of the outer edge relative to the center in the Y-axis direction. Fig.13 As shown in , when the negative warping amount in the Y-axis direction is -300 μm and the positive warping amount in the X-axis direction is +70 μm, it can be said that the bonding surface W2j is greatly extended in the Y-axis direction and slightly contracted in the X-axis direction.

[0115] In this way, when the influence of the elongation on the joint surface W2j is large, the lower retaining plate 231 is arranged so that the joint surface W2j is in the radial direction where the elongation occurs (in the Fig.13The lower wafer W2 is adsorbed by shrinking in the direction of the Y-axis (in the Y-axis direction), thereby improving the distribution of residual stress of the lower wafer W2. Specifically, when the lower holding disk 231 adsorbs the lower wafer W2, the bonding device 1 sequentially adsorbs the lower wafer W2 from the outer edge toward the center of the lower wafer W2. In this way, the lower holding disk 231 can guide the bonding surface W2j to shrink toward the center of the lower wafer W2 by first fixing the outer edge of the lower wafer W2. Hereinafter, the adsorption action from the outer edge to the center of the lower wafer W2 in the adsorption surface 300 is referred to as the outer center mode.

[0116] On the contrary, when the influence of contraction is large on the joint surface W2j, the lower retaining plate 231 is arranged so that the joint surface W2j is in the radial direction where contraction occurs (in the Fig.13 The lower wafer W2 is adsorbed in a manner that the lower wafer W2 is extended in the X-axis direction (in the X-axis direction), thereby improving the distribution of residual stress of the lower wafer W2. Specifically, when the lower holding plate 231 adsorbs the lower wafer W2, the bonding device 1 sequentially adsorbs the lower wafer W2 from the center toward the outer edge of the lower wafer W2. Thus, the lower holding plate 231 can guide the bonding surface W2j to extend toward the outer edge of the lower wafer W2 by first fixing the center of the lower wafer W2. Hereinafter, the adsorption action from the center toward the outer edge of the lower wafer W2 in the adsorption surface 300 is referred to as the center-outer mode.

[0117] The control device 90 of the bonding device 1 improves the distribution of residual stress of the lower wafer W2 adsorbed on the adsorption surface 300 by selecting between the outer center mode and the center outer mode according to the state of the warping of the lower wafer W2. For example, the control device 90 compares the absolute value of the warping amount in the X-axis direction of the lower wafer W2 with the absolute value of the warping amount in the Y-axis direction, and selects between the outer center mode and the center outer mode based on the form of the warping (negative warping, positive warping) with a larger absolute value of the warping amount. When adsorbing the lower wafer W2, an outer first zone for adsorbing the lower wafer W2 and an outer second zone for adsorbing the lower wafer W2 later than the outer first zone are set in each zone in the circumferential direction of the outer region C. For example, as Fig.11 As shown, the first outer zone is a zone (ch7, ch8) along the Y-axis direction of the adsorption surface 300, and the second outer zone is a zone (ch5, ch6) that is 90° phase-shifted from the first outer zone along the circumferential direction of the adsorption surface 300. Alternatively, the first outer zone may also be a zone (ch5, ch6) along the X-axis direction of the adsorption surface 300, in which case the second outer zone can be a zone (ch7, ch8) that is 90° phase-shifted from the first outer zone along the circumferential direction of the adsorption surface 300.

[0118] In addition, the bonding device 1 may also set a middle first zone and a middle second zone in each zone of the middle region B. The middle first zone is a zone located adjacent to the outer first zone. When ch7 and ch8 are the outer first zones and ch5 and ch6 are the outer second zones, ch3 becomes the middle first zone and ch2 becomes the middle second zone. When ch5 and ch6 are the outer first zones and ch7 and ch8 are the outer second zones, ch2 becomes the middle first zone and ch3 becomes the middle second zone.

[0119] However, the control device 90 can adjust the timing of the adsorption action of each zone in the lower wafer W2 in more detail by first performing the outer center mode and then performing the center outer mode when the lower wafer W2 is adsorbed by the lower holding plate 231. In this way, the residual stress of the lower wafer W2 can be further dispersed. The action of the lower holding plate 231 when adsorbing the lower wafer W2 is specifically described below.

[0120] First of all, Fig.13 The case shown in FIG. 1 is a case where negative warping is generated along the Y-axis direction, positive warping is generated along the X-axis direction, and the absolute value of the warping amount in the Y-axis direction is greater than the absolute value of the warping amount in the X-axis direction. In this case, as described above, the bonding surface W2j of the lower wafer W2 is mainly elongated along the Y-axis direction. Therefore, the control device 90 determines to perform the outer center mode in the Y-axis direction first. In addition, based on the fact that positive warping is generated along the X-axis direction, the control device 90 also determines to perform the central outer mode in the X-axis direction after performing the outer center mode in the Y-axis direction.

[0121] Furthermore, when the control device 90 lowers the plurality of holding pins 265 to absorb the lower wafer W2, Fig.14 As shown, the adsorption pressure is generated in the order of the adsorption actions of each channel set. Fig.14 In the figure, the area (channel) where adsorption pressure is generated is shaded.

[0122] In detail, Fig.14 As shown in (A), the control device 90 first generates suction pressure in the zones ch7 and ch8 of the outer region C in the Y-axis direction. Thus, the lower holding plate 231 can first fix the outer edge of the bonding surface W2j extending in the Y-axis direction.

[0123] Then, if Fig.14 As shown in (B), the control device 90 generates adsorption pressure in the central area (central area A) of the adsorption surface 300, namely, ch1. As a result, when viewed in the cross section in the Y-axis direction, an outer central mode is performed in which adsorption pressure is generated from the outer edge side to the central side of the lower wafer W2. As a result, the bonding surface W2j of the lower wafer W2 is fixed in the direction of contraction in the Y-axis direction.

[0124] Afterwards, if Fig.14 As shown in (C), the control device 90 generates adsorption pressure in the two ch3s adjacent to ch1 in the middle region B. As a result, the residual stress of the lower wafer W2 can be dispersed to the periphery while suppressing the excessive contraction of the bonding surface W2j toward the center side in the Y-axis direction, while fixing the lower wafer W2 along the Y-axis direction. In addition, the control device 90 can also be configured to generate adsorption pressure in the order of ch7, ch8 → each ch3 → ch1 in the outer center mode performed first.

[0125] Then, if Fig.14 As shown in (D), the control device 90 generates adsorption pressure in the two ch2s adjacent to ch1 in the middle region B to perform the center outer mode in the X-axis direction. Fig.14 As shown in (E), the control device 90 generates adsorption pressure in the areas adjacent to each ch2 in the outer region C, namely, ch5 and ch6. Thus, when observed in the cross section in the X-axis direction, a central outer mode is performed in which adsorption pressure is generated from the central side to the outer edge side of the lower wafer W2. As a result, the bonding surface W2j of the lower wafer W2 is fixed along the direction of extension in the X-axis direction. Alternatively, the control device 90 may also be configured such that, in the central outer mode, adsorption pressure is generated in the order of ch1→ch5, ch6→ch2. Thus, it is possible to suppress the bonding surface W2j from excessively extending toward the outer edge side in the X-axis direction, causing the residual stress to be dispersed to the surroundings.

[0126] After adsorption in the X-axis and Y-axis directions, Fig.14 As shown in (F), the control device 90 performs adsorption in a diagonal direction sandwiched between the X-axis direction and the Y-axis direction. In performing adsorption in the diagonal direction, the control device 90 first generates adsorption pressure in the middle region B, that is, the four ch4s.

[0127] Furthermore, the control device 90 generates adsorption pressure in the areas of the outer region C, namely, the two ch9 and the two ch10 (see Fig.11 ). Thus, the lower holding plate 231 can extend in the diagonal direction of the lower wafer W2 while using all areas of the adsorption surface 300 to adsorb the lower wafer W2. In addition, for example, when the elongation of the bonding surface W2j of the lower wafer W2 is large, adsorption pressure can also be generated in the diagonal direction in the order of the outer area C (ch9, ch10) → the middle area B (ch4).

[0128] As described above, the bonding device 1 can improve the distribution of residual stress of the lower wafer W2 by performing the outer center mode and the center outer mode according to the warping state of the lower wafer W2. The above-mentioned adsorption action is an example of a case where the X-axis direction is positively warped, the Y-axis direction is negatively warped, and the absolute value of the warping amount in the Y-axis direction is greater than the absolute value of the warping amount in the X-axis direction. The control device 90 performs other adsorption actions for other warping states of the lower wafer W2.

[0129] As an example, Fig.15 As shown in the table, the control device 90 can be cited as an example of selecting the adsorption action according to a plurality of condition classifications. Fig.15 In the table, the top row (the first row) is in Fig.13 and Fig.14 An example of the warpage state and adsorption action of the lower wafer W2 is described in FIG.

[0130] Fig.15 The second row of the table is a case where the X-axis direction is positively warped, the Y-axis direction is negatively warped, and the relationship of the warping amount is the absolute value of the warping amount in the X-axis direction > the absolute value of the warping amount in the Y-axis direction. In this case, it can be said that the bonding surface W2j of the lower wafer W2 shrinks mainly in the X-axis direction. Therefore, the control device 90 determines to perform the center-outer mode in the X-axis direction. Therefore, in the adsorption action, as the center-outer mode in the X-axis direction, the adsorption pressure is generated in the order of ch1→ch2→ch5, ch6.

[0131] After that, the control device 90 generates adsorption pressure in the order of ch7, ch8→ch3 in the Y-axis direction, and generates adsorption pressure in the order of ch4→ch9, ch10 in the diagonal direction. Thus, the bonding surface W2j can be guided to shrink slightly in the Y-axis direction where negative warping occurs. Alternatively, when the absolute value of the warping amount in the Y-axis direction is small, after performing the center-outer mode in the X-axis direction, the center-outer mode can be set in the Y-axis direction to generate adsorption pressure in the order of ch1→ch3→ch7, ch8.

[0132] Fig.15 The third row of the table is a case where the X-axis direction is positively warped, the Y-axis direction is negatively warped, and the relationship between the warping amounts is that the absolute value of the warping amount in the X-axis direction ≈ the absolute value of the warping amount in the Y-axis direction. In other words, it can be said that the amount of contraction of the bonding surface W2j of the lower wafer W2 in the X-axis direction is roughly equal to the amount of extension in the Y-axis direction. In this case, the control device 90 generates adsorption pressure in the order of ch1, ch7, ch8→ch2→ch5, ch6→ch3→ch4→ch9, ch10 during the adsorption action.

[0133] That is, the lower holding plate 231 can first fix the Y-axis direction of the joint surface W2j by adsorbing the central region A and the outer region C in the Y-axis direction at the same time. After that, in the same manner as in the first row, by performing the center-outside pattern in the X-axis direction, the joint surface W2j can be elongated in the X-axis direction.

[0134] Fig.15 The fourth row of the table is the case where the X-axis direction has negative warpage, the Y-axis direction has positive warpage, and the relationship of the warpage amounts is that the absolute value of the warpage amount in the X-axis direction < the absolute value of the warpage amount in the Y-axis direction. In this case, it can be said that the joint surface W2j of the lower wafer W2 mainly shrinks in the Y-axis direction. Therefore, the control device 90 determines to perform the center-outside pattern in the Y-axis direction. Thus, in the adsorption operation, the center-outside pattern in the Y-axis direction is set, and the adsorption pressure is generated in the order of ch1→ch3→ch7, ch8.

[0135] After that, the control device 90 causes the adsorption pressure to be generated in the order of ch5, ch6→ch2 in the X-axis direction, and causes the adsorption pressure to be generated in the order of ch4→ch9, ch10 in the diagonal direction. In addition, when the absolute value of the warpage amount in the X-axis direction is small, after performing the center-outside pattern in the Y-axis direction, the center-outside pattern can also be set in the X-axis direction to generate the adsorption pressure in the order of ch1→ch2→ch5, ch6.

[0136] Fig.15 The fifth row of the table is the case where the X-axis direction has negative warpage, the Y-axis direction has positive warpage, and the relationship of the warpage amounts is that the absolute value of the warpage amount in the X-axis direction > the absolute value of the warpage amount in the Y-axis direction. In this case, it can be said that the joint surface W2j of the lower wafer W2 mainly elongates in the X-axis direction. Therefore, the control device 90 determines to perform the outside-center pattern in the X-axis direction. Thus, in the adsorption operation, the outside-center pattern in the X-axis direction is set, and the adsorption pressure is generated in the order of ch5, ch6→ch1. After that, the control device 90 causes the adsorption pressure to be generated by ch2 in the X-axis direction. In addition, the control device 90 can cause the adsorption pressure to be generated in the order of ch5, ch6→ch2→ch1 in the X-axis direction according to the warpage state of the lower wafer W2.

[0137] And, after the control device 90 causes the adsorption pressure to be generated in the order of ch3→ch7, ch8 in the Y-axis direction, it causes the adsorption pressure to be generated in the order of ch4→ch9, ch10 in the diagonal direction. Or, when the absolute value of the warpage amount in the Y-axis direction is large, the control device 90 can also generate the adsorption pressure in the order of ch7, ch8→ch3.

[0138] Fig.15The sixth row of the table is a case where the X-axis direction is negatively warped, the Y-axis direction is positively warped, and the relationship between the warping amounts is that the absolute value of the warping amount in the X-axis direction ≈ the absolute value of the warping amount in the Y-axis direction. In this case, it can be said that the amount of extension of the bonding surface W2j of the lower wafer W2 in the X-axis direction is roughly equal to the amount of contraction in the Y-axis direction. Therefore, the control device 90 generates adsorption pressure in the order of ch1, ch5, ch6→ch3→ch7, ch8→ch2→ch4→ch9, ch10 during the adsorption action.

[0139] That is, the lower holding plate 231 can fix the X-axis direction of the bonding surface W2j by simultaneously adsorbing the central area A and the outer area C in the X-axis direction. Then, similarly to the fourth row, by performing the central outer mode in the Y-axis direction, the bonding surface W2j can be extended in the Y-axis direction.

[0140] As described above, the substrate processing device (joining device 1) can improve the distribution of residual stress of the lower wafer W2 and properly adsorb the lower wafer W2 by selecting between the outer central mode and the central outer mode according to the warping state of the lower wafer W2. That is, when the joint surface W2j is extended, by using the outer central mode to adsorb from the outer area C toward the central area A, stress can be applied in the direction of contraction of the joint surface W2j. Conversely, when the joint surface W2j is contracted, by using the central outer mode to adsorb from the central area A toward the outer area C, stress can be applied in the direction of extension of the joint surface W2j.

[0141] In addition, when warpage occurs in the lower wafer W2 in the orthogonal radial directions (X-axis direction, Y-axis direction), the bonding device 1 can stably perform the outer center mode and the center outer mode by selecting between the outer first zone and the outer second zone. In particular, the bonding device 1 compares the warpage amount of negative warpage with the warpage amount of positive warpage, and performs the outer center mode and the center outer mode based on the form with the larger absolute value of the warpage amount, thereby being able to more reliably disperse the residual stress of the lower wafer W2.

[0142] In addition, after the bonding apparatus 1 performs the outer center mode, it generates an adsorption pressure in the direction from the central area A toward the outer area C, thereby guiding the bonding surface W2j to smoothly extend, thereby improving the distribution of the residual stress of the lower wafer W2. In addition, the bonding apparatus 1 can well release the stress to the surrounding area by omitting the middle first area in the outer center mode, resulting in further dispersion of the residual stress.

[0143] In addition, the substrate processing device (joining device 1) involved in the present disclosure is not limited to the above-mentioned structure, and various modifications can be adopted. For example, when the warping of the lower wafer W2 occurs in the diagonal direction, the joining device 1 can also first perform adsorption in the diagonal direction, and at this time, the outer center mode and the center outer mode can also be appropriately selected.

[0144] In addition, the bonding apparatus 1 compares the absolute value of the warpage amount of the negative warpage of the lower wafer W2 with the absolute value of the warpage amount of the positive warpage to select Fig.15 For example, in the lower wafer W2 , the outer center mode may be uniformly performed in the radial direction where negative warpage occurs, and the center outer mode may be uniformly performed in the radial direction where positive warpage occurs.

[0145] Furthermore, in the above-described embodiment, the suction pressure when sucking the lower wafer W2 is set to be the same in each zone, but the present invention is not limited thereto, and different suction pressures may be set in each zone.

[0146] [Second embodiment]

[0147] Next, refer to Figure 16-17 A joining module 41A according to the second embodiment will be described. The joining module 41A is different from the joining module 41A according to the first embodiment in that it includes a lower holding plate 231A for forming a curved suction surface 400 .

[0148] The lower holding plate 231A includes, for example, a base portion 232 and a suction portion 233. The suction portion 233 is disposed above the base portion 232 and is used to suction and hold the lower wafer W2 from below. The suction portion 233 is formed into a perfect circle having a diameter greater than the diameter of the lower wafer W2 when viewed from above, and is fixed to the base portion 232 by a fixing ring 234 disposed at the peripheral portion. A pressure variable space 235 is formed between the upper surface of the base portion 232 and the lower surface of the suction portion 233.

[0149] Similar to the first embodiment, an annular rib 301, a rib 302, a rib 303, and a radial rib 305 are provided on the upper surface of the adsorption portion 233 (see Fig.11 ). Through these ribs 301, rib 302, rib 303, rib 305, as Fig.11 As shown, the suction surface 400 is also configured to have a central area A, a middle area B, and an outer area C, and the middle area B and the outer area C have a plurality of zones in the circumferential direction. The plurality of zones are set as a plurality of (ch1 to ch10) channels for independently suctioning the lower wafer W2.

[0150] In addition, the bonding module 41A includes a second deformation portion 236 that bends the lower wafer W2 by deforming the lower holding plate 231A. The second deformation portion 236 elastically deforms the adsorption portion 233 by causing a pressure change in the pressure variable space 235. The material of the adsorption portion 233 is, for example, ceramics such as alumina or silicon carbide. The second deformation portion 236 includes a vacuum pump 236a, a pressure pump 236b, and a switching valve 236c.

[0151] The vacuum pump 236a depressurizes the variable pressure space 235 by discharging the gas in the variable pressure space 235. By depressurizing the variable pressure space 235, the upper surface of the adsorption portion 233 becomes a horizontal plane. The pressure pump 236b pressurizes the variable pressure space 235 by supplying gas to the variable pressure space 235. By pressurizing the variable pressure space 235, the adsorption surface 400 of the adsorption portion 233 becomes a curved surface with a protruding central area A. The protruding amount of the central area A of the adsorption surface 400 can be adjusted by the pressure of the variable pressure space 235. The switching valve 236c switches the variable pressure space 235 between a state connected to the vacuum pump 236a and a state connected to the pressure pump 236b.

[0152] The base part 232 has a measuring part 237 for measuring the protrusion amount of the central area A of the adsorption surface 400. The measurement target 237a of the measuring part 237 is raised and lowered together with the central part of the adsorption part 233. The measuring part 237 is, for example, an electrostatic capacitance sensor, and measures the protrusion amount by detecting the electrostatic capacitance that changes according to the distance from the measurement target 237a.

[0153] like Fig.16 As shown, the bonding module 41A configured as described above sets the suction surface 400 of the lower holding plate 231A to a deformed state, and suctions the lower wafer W2 conveyed by the conveying device 61. When suctioning the lower wafer W2, as described above, the control device 90 appropriately performs the outer center mode of suctioning the lower wafer W2 from the outer side and the center outer mode of suctioning the lower wafer W2 from the center according to the warping state of the lower wafer W2.

[0154] In selecting the outer center mode and the center outer mode, the control device 90 makes a determination in consideration of the protrusion amount of the central region A of the suction surface 400 (the curvature of the entire suction surface 400 ) in addition to the warpage state of the lower wafer W2 .

[0155] For example, Fig.17As shown in the figure, when the suction surface 400 of the lower holding plate 231A protrudes 150 μm and the outer edge of the lower wafer W2 in the Y-axis direction is negatively warped by -300 μm, the curvature of the lower wafer W2 in the Y-axis direction is greater than the curvature of the suction surface 400 in the Y-axis direction. In this case, the control device 90 selects to perform the outer edge of the lower wafer W2 (ch7, ch8: refer to Fig.11 ) towards the center (ch1: refer to Fig.11 ) of the outer center mode of the adsorption action. Thus, it is possible to suppress the extension of the outer edge of the lower wafer W2 in the Y-axis direction.

[0156] On the other hand, when the suction surface 400 of the lower holding plate 231A protrudes 150 μm and the outer edge of the lower wafer W2 in the Y-axis direction is negatively warped at -100 μm, the curvature of the lower wafer W2 in the Y-axis direction is smaller than the curvature of the suction surface 400 in the Y-axis direction. In this case, even if the bonding surface W2j of the lower wafer W2 is elongated in the Y-axis direction, the elongation is less than the elongation in the loading state of the lower holding plate 231A. Therefore, the control device 90 selects to start from the center of the lower wafer W2 (ch1: refer to Fig.11 ) toward the outer edge (ch7, ch8: refer to Fig.11 ) performs the center outer mode of the adsorption operation. Thus, the bonding surface W2j of the lower wafer W2 in the Y-axis direction can be extended according to the curvature of the adsorption surface 400.

[0157] In addition, when the outer edge of the lower wafer W2 is positively warped (for example, Fig.17 In the case of the X-axis direction of the lower wafer W2, the wafer is warped in the opposite direction to the curved surface of the adsorption surface 400. Therefore, the control device 90 always selects the center outer mode for positive warping. Thus, the bonding module 41A can smoothly extend the bonding surface W2j relative to the positive warping of the lower wafer W2.

[0158] As described above, in the bonding module 41A involved in the second embodiment, the distribution of residual stress of the lower wafer W2 can also be improved by selecting the outer center mode or the center outer mode to adsorb the lower wafer W2. In particular, the bonding module 41 forms a curved surface by forming the adsorption surface 400, which can reduce the difference in elongation between the upper wafer W1 and the lower wafer W2 during bonding, thereby reducing the offset between the upper wafer W1 and the lower wafer W2 after bonding.

[0159] The substrate processing apparatus and substrate processing method involved in the embodiments disclosed herein are illustrative in all respects and are not restrictive. The embodiments can be modified and improved in various ways without departing from the attached claims and their gist. The matters described in the above-mentioned multiple embodiments can also adopt other structures within the scope of non-contradiction, and can also be combined within the scope of non-contradiction.

[0160] This application claims the priority of basic application No. 2022-135106 filed with the Japan Patent Office on August 26, 2022, and all the contents are incorporated herein by reference.

[0161] Description of Reference Numerals

[0162] 1: bonding device (substrate processing device); 90: control device (control unit); 231, 231A: lower holding plate (holding unit); 300, 400: adsorption surface; 310: adsorption pressure generating unit; A: central area; C: outer area; W2: lower wafer.

Claims

1. A substrate processing device, comprising: A holding portion, wherein a suction surface of the holding portion for suctioning the substrate has a circular central region and an annular outer region disposed at an outer side than the central region; an adsorption pressure generating unit that generates adsorption pressure independently in the central region, an outer first region set at one position in the circumferential direction of the outer region, and an outer second region set at a position different from the outer first region in the circumferential direction of the outer region; and a control unit that controls the adsorption pressure generating unit, in, The control unit selects between an outer central mode and a central outer mode according to the warping state of the substrate. The outer central mode generates adsorption pressure in the order of the outer first zone and the central zone, and the central outer mode generates adsorption pressure in the order of the central zone and the outer first zone.

2. The substrate processing apparatus according to claim 1, wherein: The substrate has a first form or a second form, the first form is a form in which the outer edge of the substrate is warped in a direction closer to the adsorption surface relative to the center before the control unit generates the adsorption pressure on the adsorption surface, and the second form is a form in which the outer edge of the substrate is warped in a direction away from the adsorption surface relative to the center before the control unit generates the adsorption pressure on the adsorption surface. The control unit performs the outer center mode when a predetermined radial direction of the substrate is in the first state, and performs the center outer mode when a predetermined radial direction of the substrate is in the second state.

3. The substrate processing apparatus according to claim 2, wherein: The radial direction of the first shape and the radial direction of the second shape of the substrate are orthogonal to each other at the center. The outer first area and the outer second area are set at positions that are 90° out of phase with each other along the circumferential direction of the adsorption surface.

4. The substrate processing apparatus according to claim 3, wherein: The control unit compares the warping amount of the outer edge of the substrate with respect to the center in the first form with the warping amount of the outer edge of the substrate with respect to the center in the second form, When the absolute value of the warping amount in the first mode is larger than the absolute value of the warping amount in the second mode, the outer center mode is performed. When the absolute value of the warping amount in the first mode is smaller than the absolute value of the warping amount in the second mode, the center outer mode is performed.

5. The substrate processing apparatus according to claim 4, wherein: After performing the outer center mode in the radial direction of the first form of the substrate, the control unit generates adsorption pressure in the order of the center region and the outer second region in the radial direction of the second form of the substrate.

6. The substrate processing apparatus according to any one of claims 1 to 5, wherein: The adsorption surface has a circular middle area between the central area and the outer area. The middle region has a middle first region at a position adjacent to the outer first region, and has a middle second region at a position adjacent to the outer second region, The control unit generates adsorption pressure in the order of the central region, the middle first region, and the outer first region in the center outer mode.

7. The substrate processing apparatus according to claim 6, wherein: The control unit omits the middle first region in the outer center mode so that the adsorption pressure is generated in the order of the outer first region and the center region.

8. The substrate processing apparatus according to any one of claims 1 to 5, wherein: The adsorption surface is formed as a curved surface in which the central area protrudes more than the outer area.

9. The substrate processing apparatus according to claim 8, wherein: When the outer edge of the substrate is warped relative to the center in a direction approaching the adsorption surface, the control unit compares the curvature of the substrate accompanying the warping with the curvature of the adsorption surface. When the curvature of the substrate is greater than the curvature of the adsorption surface, the outer center mode is performed. When the curvature of the substrate is smaller than the curvature of the adsorption surface, the center-outer mode is performed.

10. The substrate processing apparatus according to any one of claims 1 to 5, wherein: The control unit acquires measurement information obtained by measuring the warpage of the substrate, and selects the outer center mode or the center outer mode based on the measurement information.

11. The substrate processing apparatus according to any one of claims 1 to 5, wherein: The substrate processing apparatus is a bonding apparatus that bonds the substrate sucked by the holding portion to another substrate disposed at a position facing the substrate.

12. The substrate processing apparatus according to claim 11, wherein: The holding portion is a lower holding plate that sucks and holds the other substrate at a lower side in a vertical direction of the other substrate.

13. A substrate processing method, comprising: performing substrate processing while the substrate is adsorbed on an adsorption surface of a holding portion, The substrate processing method comprises the following steps: generating adsorption pressure independently in a circular central area, an outer first area and an outer second area set on the adsorption surface by an adsorption pressure generating unit, wherein the outer first area is set at a position on the circumference of the circular outer area arranged at a position outside the central area, and the outer second area is set at a position on the circumference of the outer area different from the outer first area, Before generating the adsorption pressure, a selection is made between an outer central mode and a central outer mode according to the warping state of the substrate, wherein the outer central mode generates the adsorption pressure in the order of the outer first area and the central area, and the central outer mode generates the adsorption pressure in the order of the central area and the outer first area. In the step of generating the suction pressure, the substrate is suctioned onto the suction surface in the order of the selected patterns.

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