Substrate processing apparatus, measuring apparatus and measuring method

Abstract

To provide a technique capable of precisely measuring the position of a substrate.SOLUTION: A substrate processing apparatus comprises a retention part which retains a substrate detachably, an optical sensor which is provided at the retention part and irradiates the substrate with measurement light and also receives reflected light from the substrate, a transparent member which is arranged in a measurement optical path between the substrate and the optical sensor and can transmit light, and a processing part which processes measurement information of the optical sensor. The processing part acquires the distance between the substrate and the transparent member based upon the measurement information, and recognizes the position of the substrate.SELECTED DRAWING: Figure 12

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing apparatus, a measuring apparatus, and a measuring method. [Background technology]

[0002] Patent Document 1 discloses a bonding device that includes an upper chuck that adsorbs the upper substrate from above and a lower chuck that adsorbs the lower substrate from below, and that bonds two substrates face to face. In bonding the substrates, the bonding device presses down the center of the substrate on the upper chuck to bring it into contact with the center of the substrate on the lower chuck, bonds the centers of the two substrates together using intermolecular forces, and expands the bonding area from the center to the periphery.

[0003] Furthermore, the bonding device described in Patent Document 1 is provided with a plurality of sensors on the upper chuck that detect the progress of bonding (bonding wave) between the substrates. For example, the plurality of sensors are arranged at equal intervals along the circumferential direction of the outer periphery of the upper chuck, and by measuring the height position of the upper substrate, the progress of bonding can be recognized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6929427 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure provides a technique that can measure the position of a substrate with high accuracy. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, there is provided a substrate processing apparatus comprising: a holding section for detachably holding a substrate; an optical sensor provided on the holding section for irradiating measurement light onto the substrate and receiving reflected light from the substrate; a transparent member capable of transmitting light and arranged in a measurement light path between the substrate and the optical sensor; and a processing section for processing measurement information from the optical sensor, wherein the processing section obtains the distance between the substrate and the transparent member based on the measurement information and recognizes the position of the substrate. [Effects of the Invention]

[0007] According to one aspect, the position of the substrate can be measured with high precision. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. [Figure 2] FIG. 2 is a side view of the joining device of FIG. [Figure 3] FIG. 2 is a side view showing an example of a first substrate and a second substrate. [Figure 4] 1 is a flowchart showing a joining method. [Figure 5] FIG. 2 is a plan view showing an example of a joining module according to the first embodiment. [Figure 6] FIG. 6 is a side view of the splice module of FIG. 5. [Figure 7] FIG. 2 is a cross-sectional view showing an example of an upper chuck and a lower chuck. [Figure 8] 5 is a flowchart showing details of step S109 in FIG. 4. [Figure 9] Fig. 9(A) is a side view showing an example of the operation in step S112 of Fig. 8. Fig. 9(B) is a side view showing the operation following Fig. 9(A). Fig. 9(C) is a side view showing the operation following Fig. 9(B). [Figure 10] Fig. 10(A) is a cross-sectional view showing an example of the operation in step S113 of Fig. 8. Fig. 10(B) is a cross-sectional view showing an example of the operation in step S114 of Fig. 8. Fig. 10(C) is a cross-sectional view showing the operation subsequent to Fig. 10(B). [Figure 11] FIG. 10 is a cross-sectional view showing an upper chuck on which a displacement sensor is installed. [Figure 12] FIG. 4 is an enlarged cross-sectional view showing an outer displacement sensor and a gas discharge portion. [Figure 13] 10A and 10B are diagrams illustrating calculation of the distance between the transparent member and the upper wafer. [Figure 14] Fig. 14(A) is a diagram showing the measurement state of a displacement sensor according to a reference example. Fig. 14(B) is a diagram showing the measurement state of a displacement sensor according to a reference example in which a void-reducing gas has flowed into the measurement optical path. Fig. 14(C) is a diagram showing the measurement state of a displacement sensor according to an embodiment. Fig. 14(D) is a diagram showing the measurement state of a displacement sensor according to an embodiment in which a void-reducing gas has flowed into the measurement optical path. [Figure 15] 10 is a flowchart showing a process of bonding an upper wafer and a lower wafer, including a measurement method. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same components are denoted by the same reference numerals, and duplicated descriptions may be omitted. Note that the X-axis, Y-axis, and Z-axis directions used in the following description are axes that intersect perpendicularly with each other, the X-axis and Y-axis directions are horizontal directions, and the Z-axis direction is vertical.

[0010] As a representative substrate processing apparatus of the present disclosure, a bonding apparatus 1 shown in FIGS. 1 and 2 will be described. The bonding apparatus 1 bonds a first substrate W1 and a second substrate W2 to produce a bonded substrate T. At least one of the first substrate W1 and the second substrate W2 is a semiconductor substrate, such as a silicon wafer or a compound semiconductor wafer, on which multiple electronic circuits are formed. One of the first substrate W1 and the second substrate W2 may be a bare wafer on which no electronic circuits are formed. The compound semiconductor wafer is not particularly limited, but may be, for example, a GaAs wafer, a SiC wafer, a GaN wafer, or an InP wafer.

[0011] The first substrate W1 and the second substrate W2 are formed as circular plates of approximately the same shape (same diameter). As shown in FIG. 3, the bonding apparatus 1 places the second substrate W2 on the negative Z-axis side (vertically below) of the first substrate W1 and bonds the first substrate W1 and the second substrate W2. Therefore, hereinafter, the first substrate W1 may be referred to as the "upper wafer W1," the second substrate W2 as the "lower wafer W2," and the bonded substrate T as the "bonded wafer T." Furthermore, hereinafter, the surface of the upper wafer W1 that is bonded to the lower wafer W2 will be referred to as the "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as the "non-bonding surface W1n." Furthermore, the surface of the lower wafer W2 that is bonded to the upper wafer W1 will be referred to as the "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as the "non-bonding surface W2n."

[0012] 1, the bonding apparatus 1 includes, in order in the positive direction of the X-axis, a carry-in / out station 2 and a processing station 3. The carry-in / out station 2 and the processing station 3 are integrally connected.

[0013] The carry-in / out station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 has a plurality of mounting plates 11. Each mounting plate 11 is loaded with a cassette CS1, CS2, or CS3, which stores a plurality of substrates (e.g., 25 substrates) in a horizontal position. The cassette CS1 stores an upper wafer W1, the cassette CS2 stores a lower wafer W2, and the cassette CS3 stores a bonded wafer T. In the cassettes CS1 and CS2, the upper wafer W1 and the lower wafer W2 are stored with their respective bonding surfaces W1j and W2j facing upward and aligned in the same direction.

[0014] The transfer region 20 is disposed adjacent to the mounting table 10 on the positive side of the X axis, and includes a transfer path 21 extending in the Y axis direction, and a transfer device 22 movable along the transfer path 21. The transfer device 22 is movable also in the X axis direction and rotatable about the Z axis, and transfers the upper wafer W1, the lower wafer W2, and the bonded wafer T between the cassettes CS1 to CS3 placed on the mounting table 10 and a third processing block PB3 of the processing station 3, which will be described later.

[0015] Processing station 3 includes, for example, three processing blocks PB1, PB2, and PB3. The first processing block PB1 is provided on the rear side of processing station 3 (the positive Y-axis side in FIG. 1). The second processing block PB2 is provided on the front side of processing station 3 (the negative Y-axis side in FIG. 1). The third processing block PB3 is provided on the loading / unloading station 2 side of processing station 3 (the negative X-axis side in FIG. 1).

[0016] Furthermore, processing station 3 includes a transfer region 60 having a transfer device 61 in an area surrounded by first processing block PB1 to third processing block PB3. For example, transfer device 61 has a transfer arm that is movable vertically, horizontally, and around a vertical axis. Transfer device 61 moves within transfer region 60 to transfer upper wafer W1, lower wafer W2, and bonded wafer T to devices in first processing block PB1, second processing block PB2, and third processing block PB3 adjacent to transfer region 60.

[0017] 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.

[0018] For example, the surface modification device 33 breaks SiO2 bonds on the bonding surfaces W1j and W2j, forming dangling Si bonds and enabling subsequent hydrophilization. In the surface modification device 33, for example, oxygen gas, which is a processing gas, is excited to plasma and ionized under a reduced pressure. The oxygen ions are then irradiated onto the bonding surfaces W1j of the upper wafer W1 and W2j of the lower wafer W2, thereby subjecting the bonding surfaces W1j and W2j to plasma processing and modification. The processing gas is not limited to oxygen gas, and may be nitrogen gas or the like.

[0019] The surface hydrophilization device 34 hydrophilizes the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 using a hydrophilization treatment liquid such as pure water. The surface hydrophilization device 34 also serves to clean the bonding surfaces W1j and W2j. In the surface hydrophilization device 34, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by, for example, a spin chuck. As a result, the pure water diffuses over the bonding surfaces W1j and W2j, attaching OH groups to the dangling bonds of Si, and the bonding surfaces W1j and W2j are hydrophilized.

[0020] 2, the second processing block PB2 includes, for example, a bonding module 41, a first temperature adjustment device 42, and a second temperature adjustment device 43. The bonding module 41 bonds a hydrophilized upper wafer W1 and a lower wafer W2 to produce a bonded wafer T. The first temperature adjustment device 42 adjusts the temperature distribution of the upper wafer W1 before producing the bonded wafer T. The second temperature adjustment device 43 adjusts the temperature distribution of the lower wafer W2 before producing the bonded wafer T. In this embodiment, the first temperature adjustment device 42 and the second temperature adjustment device 43 are provided separately from the bonding module 41, but they may also be provided as part of the bonding module 41.

[0021] The third processing block PB3 includes, for example, a first position adjustment device 51, a second position adjustment device 52, and transition devices 53 and 54, arranged in this order from top to bottom. Note that the locations of the devices in the third processing block PB3 are not limited to those shown in FIG. 2. The first position adjustment device 51 adjusts the horizontal orientation 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 orientation of the lower wafer W2. The transition device 53 temporarily places the upper wafer W1 thereon. The transition device 54 temporarily places the lower wafer W2 and the bonded wafer T thereon.

[0022] Returning to FIG. 1 , the bonding apparatus 1 includes a control device (controller) 90 that controls each component. The control device 90 is a control computer having one or more processors 91, a memory 92, an input / output interface (not shown), and an electronic circuit. The one or more processors 91 are one or a combination of a central processing unit (CCPU), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a circuit made up of multiple discrete semiconductors, and the like. The memory 92 includes non-volatile memory and volatile memory and forms a storage unit of the control device 90. In other words, in the present disclosure, the control device 90 is an electronic circuit having a CPU, a GPU, an ASIC, an FPGA, or the like, and performs various control operations described in this specification by executing instruction codes stored in the memory 92 or by being a circuit designed for a specific application.

[0023] Next, the joining method of this embodiment will be described with reference to Fig. 4. Steps S101 to S109 shown in Fig. 4 are performed under the control of the control device 90.

[0024] In the bonding method, an operator or a transport robot (not shown) places a cassette CS1 containing multiple upper wafers W1, a cassette CS2 containing multiple lower wafers W2, and an empty cassette CS3 on the loading / unloading station 2 on the loading / unloading stage 10.

[0025] The bonding apparatus 1 uses the transfer device 22 to remove the upper wafer W1 from the cassette CS1 and transfer it to the transition device 53 in the third processing block PB3 of the processing station 3. Thereafter, the bonding apparatus 1 uses the transfer device 61 to remove the upper wafer W1 from the transition device 53 and transfer it to the surface modification device 33 in the first processing block PB1.

[0026] Next, the bonding apparatus 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 transfer device 61 removes the upper wafer W1 from the surface modification device 33 and transfers it to the surface hydrophilization device 34.

[0027] Then, the bonding apparatus 1 causes the surface hydrophilizing device 34 to hydrophilize the bonding surface W1j of the upper wafer W1 (step S102). The surface hydrophilizing device 34 hydrophilizes the bonding surface W1j with the bonding surface W1j facing upward. Thereafter, the transfer device 61 takes out the upper wafer W1 from the surface hydrophilizing device 34 and transfers it to the first position adjustment device 51 in the third processing block PB3.

[0028] The bonding apparatus 1 adjusts the horizontal orientation of the upper wafer W1 using the first position adjustment device 51 and turns the upper wafer W1 upside down (step S103). As a result, the notch of the upper wafer W1 is oriented in a predetermined direction and the bonding surface W1j of the upper wafer W1 faces downward. Thereafter, the transfer device 61 removes the upper wafer W1 from the first position adjustment device 51 and transfers it to the first temperature adjustment device 42 in the second processing block PB2.

[0029] The bonding apparatus 1 adjusts the temperature of the upper wafer W1 by 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. Thereafter, the transfer device 61 takes out the upper wafer W1 from the first temperature adjustment device 42 and transfers it to the bonding module 41.

[0030] The bonding apparatus 1 performs processing on the lower wafer W2 in parallel with the above processing on the upper wafer W1. First, the bonding apparatus 1 causes the transfer device 22 to remove the lower wafer W2 from the cassette CS2 and transfer it to the transition device 54 in the third processing block PB3 of the processing station 3. Thereafter, the transfer device 61 removes the lower wafer W2 from the transition device 54 and transfers it to the surface modification device 33 in the first processing block PB1.

[0031] The bonding apparatus 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. Thereafter, the transfer device 61 removes the lower wafer W2 from the surface modification device 33 and transfers it to the surface hydrophilization device .

[0032] The bonding apparatus 1 hydrophilizes the bonding surface W2j of the lower wafer W2 using the surface hydrophilization device 34 (step S106). The surface hydrophilization device 34 hydrophilizes the bonding surface W2j with the bonding surface W2j facing upward. Thereafter, the transfer device 61 removes the lower wafer W2 from the surface hydrophilization device 34 and transfers it to the second position adjustment device 52 in the third processing block PB3.

[0033] The bonding apparatus 1 adjusts the horizontal orientation of the lower wafer W2 using the second position adjustment device 52 (step S107). This orients the notch of the lower wafer W2 in a predetermined direction. Thereafter, the transfer device 61 removes the lower wafer W2 from the second position adjustment device 52 and transfers it to the second temperature adjustment device 43 in the second processing block PB2.

[0034] The bonding apparatus 1 adjusts the temperature of the lower wafer W2 by 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. Thereafter, the transfer device 61 takes out the lower wafer W2 from the second temperature adjustment device 43 and transfers it to the bonding module 41.

[0035] 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 transfer device 61 takes the bonded wafer T out of the bonding module 41 and transfers it to the transition device 54 in the third process block PB3.

[0036] Finally, the bonding apparatus 1 causes the transfer device 22 to take out the bonded wafer T from the transition device 54 and transfer it to the cassette CS3 on the mounting table 10. This completes the series of processes.

[0037] Next, an example of a bonding module 41 according to an embodiment will be described with reference to Fig. 5 to Fig. 7. As shown in Fig. 5, the bonding module 41 has a processing container 210 whose interior can be sealed. A loading / unloading port 211 is formed on the side of the processing container 210 on the transfer region 60 side, and the loading / unloading port 211 is provided with an opening / closing shutter 212. The upper wafer W1, the lower wafer W2, and the bonded wafer T are loaded and unloaded through the loading / unloading port 211.

[0038] 6, an upper chuck 230 and a lower chuck 231 are provided inside the processing vessel 210. The upper chuck 230 is a first holding part that releasably (displaceably) holds the upper wafer W1 from above with the bonding surface W1j of the upper wafer W1 facing downward. The lower chuck 231 is a second holding part that is provided below the upper chuck 230 and holds the lower wafer W2 from below with the bonding surface W2j of the lower wafer W2 facing upward. In other words, the upper chuck 230 and the lower chuck 231 are holding parts that releasably hold the upper wafer W1 and the lower wafer W2, which are substrates.

[0039] The upper chuck 230 is supported by a support member 220 provided on the ceiling surface of the processing vessel 210. On the other hand, the lower chuck 231 is supported by a first lower chuck moving part 291 provided below the lower chuck 231.

[0040] As will be described later, the first lower chuck moving part 291 moves the lower chuck 231 in the horizontal direction (Y-axis direction). The first lower chuck moving part 291 is configured to be able to move the lower chuck 231 vertically and to rotate it around a vertical axis.

[0041] The first lower chuck moving part 291 is provided on the underside of the first lower chuck moving part 291 and is attached to a pair of rails 295 extending in the horizontal direction (Y-axis direction). The first lower chuck moving part 291 is configured to be movable along the rails 295. The rails 295 are provided on a second lower chuck moving part 296.

[0042] The second lower chuck moving part 296 is provided on the lower surface side of the second lower chuck moving part 296 and is attached to a pair of rails 297 extending in the horizontal direction (X-axis direction). The second lower chuck moving part 296 is configured to be movable along the rails 297. The pair of rails 297 is provided on a mounting part 298 provided on the bottom surface of the processing vessel 210.

[0043] The first lower chuck moving part 291 and the second lower chuck moving part 296 constitute a moving mechanism 290. The moving mechanism 290 moves the lower chuck 231 relative to the upper chuck 230. The moving mechanism 290 also moves the lower chuck 231 between a substrate transfer position and a bonding position.

[0044] The substrate transfer position is a position where the upper chuck 230 receives the upper wafer W1 from the transfer device 61, the lower chuck 231 receives the lower wafer W2 from the transfer device 61, and the lower chuck 231 transfers the bonded wafer T to the transfer device 61. The substrate transfer position is a position where the bonded wafer T produced in the nth (n is a natural number greater than or equal to 1) bonding is successively transferred out and the upper wafer W1 and lower wafer W2 to be bonded in the n+1th bonding are transferred in. The substrate transfer position is, for example, a position shown in FIGS. 5 and 6.

[0045] The transfer device 61 enters directly below the upper chuck 230 when transferring the upper wafer W1 to the upper chuck 230. Furthermore, the transfer device 61 enters directly above the lower chuck 231 when receiving the bonded wafer T from the lower chuck 231 and transferring the lower wafer W2 to the lower chuck 231. To facilitate the transfer of the transfer device 61, the upper chuck 230 and the lower chuck 231 are shifted laterally, and the vertical distance between the upper chuck 230 and the lower chuck 231 is also large.

[0046] On the other hand, the bonding position is a position (opposing position) where the upper wafer W1 and the lower wafer W2 are faced to each other with a predetermined gap therebetween. The bonding position is, for example, the position shown in FIG. 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 transfer position. Also, at the bonding position, unlike at the substrate transfer position, the upper wafer W1 and the lower wafer W2 overlap when viewed in the vertical direction.

[0047] The moving mechanism 290 moves the relative positions of the upper chuck 230 and the lower chuck 231 in the horizontal direction (both the X-axis direction and the Y-axis direction) and the vertical direction. In this embodiment, the moving mechanism 290 moves the lower chuck 231, but it may move either the lower chuck 231 or the upper chuck 230, or may move both. The moving mechanism 290 may also rotate the upper chuck 230 or the lower chuck 231 around a vertical axis.

[0048] 7, the upper chuck 230 is partitioned into a plurality of (for example, three) regions 230a, 230b, and 230c along the radial direction of the upper chuck 230. These regions 230a, 230b, and 230c are provided in this order from the center toward the outer edge of the upper chuck 230. The region 230a is formed in a perfect circular shape in a plan view, and the regions 230b and 230c are formed in annular shapes in a plan view.

[0049] Suction pipes 240a, 240b, and 240c are provided independently for the respective regions 230a, 230b, and 230c. Different vacuum pumps 241a, 241b, and 241c are connected to the respective suction pipes 240a, 240b, and 240c. The upper chuck 230 can vacuum-suck the upper wafer W1 for each of the regions 230a, 230b, and 230c.

[0050] The upper chuck 230 has multiple radially and annularly extending ribs 230r (see FIG. 12), and the protruding ends of these ribs 230r form suction surfaces. Suction pipes 240a, 240b, and 240c communicate with the pipe installation bottom surfaces between the ribs 230r, and apply suction pressure to the spaces between the upper wafer W1, the ribs 230r, and the pipe installation bottom surfaces, thereby suctioning the upper wafer W1. The height of each rib 230r from the pipe installation bottom surface is not particularly limited, but is set to, for example, about 0.2 mm.

[0051] The upper chuck 230 is provided with a plurality of holding pins 245 that can be raised and lowered in the vertical direction. The plurality of holding pins 245 are connected to a vacuum pump 246, and vacuum-suck the upper wafer W1 by operating the vacuum pump 246. The upper wafer W1 is vacuum-sucked to the lower ends of the plurality of holding pins 245. Ring-shaped suction pads may be used instead of the plurality of holding pins 245.

[0052] The multiple holding pins 245 are lowered by a drive unit (not shown) to protrude from the chucking surface of the upper chuck 230. In this state, the multiple holding pins 245 vacuum-suck the upper wafer W1 and receive it from the transfer device 61. Thereafter, the multiple holding pins 245 rise, and the upper wafer W1 comes into contact with the chucking surface of the upper chuck 230. Next, the upper chuck 230 vacuum-sucks the upper wafer W1 horizontally in each of the regions 230a, 230b, and 230c by operating the vacuum pumps 241a, 241b, and 241c.

[0053] The upper chuck 230 also has a through-hole 243 at its center that passes through the upper chuck 230 in the vertical direction. A pushing unit 250 is inserted into the through-hole 243. The pushing unit 250 pushes down the center of the upper wafer W1, which is disposed at an interval from the lower wafer W2, to bring the upper wafer W1 into contact with the lower wafer W2.

[0054] The pushing unit 250 has a pushing pin 251 and an outer cylinder 252 that serves as a lifting guide for the pushing pin 251. The pushing pin 251 is inserted into the through-hole 243 by, for example, a drive unit (not shown) having a built-in motor, protrudes from the suction surface of the upper chuck 230, and pushes down the center of the upper wafer W1.

[0055] The lower chuck 231 is also partitioned into a plurality of (for example, two) regions 231a and 231b along the radial direction of the lower chuck 231. These regions 231a and 231b are provided in this order from the center of the lower chuck 231 toward the outer edge. The region 231a is formed in a perfect circular shape in a plan view, and the region 231b is formed in an annular shape in a plan view. The region 231b may have a plurality of arc-shaped zones (small regions) along the circumferential direction.

[0056] Suction pipes 260a and 260b are provided independently for the respective regions 231a and 231b. Different vacuum pumps 261a and 261b are connected to the respective suction pipes 260a and 260b. This allows the lower chuck 231 to vacuum-suck the lower wafer W2 for each of the regions 231a and 231b.

[0057] The lower chuck 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. The lower wafer W2 may be vacuum-sucked to the upper ends of the plurality of holding pins 265.

[0058] As the multiple holding pins 265 rise, they protrude from the suction surface of the lower chuck 231. In this state, the multiple holding pins 265 receive the lower wafer W2 from the transfer device 61. Thereafter, the multiple holding pins 265 descend, causing the lower wafer W2 to come into contact with the suction surface of the lower chuck 231. Next, the lower chuck 231 horizontally vacuum-sucks the lower wafer W2 in multiple regions of the suction surface.

[0059] Next, the process of producing the bonded wafer T in step S109 of Fig. 4 will be described in detail with reference to Fig. 8 to Fig. 10. As shown in Fig. 8, the control device 90 causes the transfer device 61 to load the upper wafer W1 and the lower wafer W2 into the bonding module 41 (step S111). After the loading, the relative positions of the upper chuck 230 and the lower chuck 231 are the substrate transfer positions shown in Figs. 6 and 7.

[0060] Next, the control device 90 causes the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the substrate transfer position to the bonding position shown in Fig. 7 (step S112). In this step S112, the control device 90 aligns the upper wafer W1 and the lower wafer W2 using the first camera S1 and the second camera S2 as shown in Fig. 9.

[0061] The first camera S1 is fixed to the upper chuck 230 and captures an image of the lower wafer W2 held by the lower chuck 231. A plurality of reference points P21 to P23 are formed in advance on the bonding surface W2j of the lower wafer W2. The reference points P21 to P23 are formed by using patterns of electronic circuits or the like. The number of reference points can be set arbitrarily.

[0062] On the other hand, the second camera S2 is fixed to the lower chuck 231 and captures an image of the upper wafer W1 held by the upper chuck 230. A plurality of reference points P11 to P13 are formed in advance on the bonding surface W1j of the upper wafer W1. The reference points P11 to P13 are formed by using patterns of electronic circuits or the like. The number of reference points can be set arbitrarily.

[0063] 9(A), the joining module 41 adjusts the relative horizontal positions of the first camera S1 and the second camera S2 using the movement mechanism 290. Specifically, the movement mechanism 290 moves the lower chuck 231 in the horizontal direction so that the second camera S2 is positioned approximately directly below the first camera S1. Then, the first camera S1 and the second camera S2 capture an image of a common target X, and the movement mechanism 290 finely adjusts the horizontal position of the second camera S2 so that the horizontal positions of the first camera S1 and the second camera S2 match.

[0064] 9(B), the movement mechanism 290 moves the lower chuck 231 vertically upward to adjust the horizontal positions of the upper chuck 230 and the lower chuck 231. Specifically, while the movement mechanism 290 moves the lower chuck 231 horizontally, the first camera S1 sequentially captures images of reference points P21 to P23 on the lower wafer W2, and the second camera S2 sequentially captures images of reference points P11 to P13 on the upper wafer W1. Note that FIG. 9(B) shows how the first camera S1 captures the image of reference point P21 on the lower wafer W2, and the second camera S2 captures the image of reference point P11 on the upper wafer W1.

[0065] The first camera S1 and the second camera S2 transmit the captured image data to the control device 90. The control device 90 controls the movement mechanism 290 based on the image data captured by the first camera S1 and the image data captured by the second camera S2, and adjusts the horizontal position of the lower chuck 231 so that the reference points P11 to P13 of the upper wafer W1 and the reference points P21 to P23 of the lower wafer W2 coincide with each other when viewed in the vertical direction.

[0066] 9(C), the moving mechanism 290 moves the lower chuck 231 vertically upward. As a result, the gap G (see FIG. 7) between the bonding surface W2j of the lower wafer W2 and the bonding surface W1j of the upper wafer W1 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.

[0067] The first displacement meter S3, like the first camera S1, is fixed to the upper chuck 230 and measures the thickness of the lower wafer W2 held by the lower chuck 231. The first displacement meter S3 measures the thickness of the lower wafer W2 by, for example, irradiating light onto the lower wafer W2 and receiving light reflected from both the upper and lower surfaces of the lower wafer W2. This thickness measurement is performed, for example, when the movement mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the first displacement meter S3 is, for example, a confocal method, a spectral interference method, or a triangulation method. The light source of the first displacement meter S3 is an LED or a laser.

[0068] On the other hand, the second displacement meter S4, like the second camera S2, is fixed to the lower chuck 231 and measures the thickness of the upper wafer W1 held by the upper chuck 230. The second displacement meter S4 measures the thickness of the upper wafer W1 by, for example, irradiating light onto the upper wafer W1 and receiving light reflected from both the upper and lower surfaces of the upper wafer W1. This thickness measurement is performed, for example, when the movement mechanism 290 moves the lower chuck 231 in the horizontal direction. The measurement method of the second displacement meter S4 is, for example, a confocal method, a spectral interference method, or a triangulation method. The light source of the second displacement meter S4 is an LED or a laser.

[0069] The first displacement meter S3 and the second displacement meter S4 transmit the measured data to the control device 90. The control device 90 controls the moving mechanism 290 based on the data measured by the first displacement meter S3 and the data measured by the second displacement meter S4, and adjusts the vertical position of the lower chuck 231 so that the gap G becomes a set value.

[0070] Next, the operation of the vacuum pump 241a is stopped, and the vacuum suction of the upper wafer W1 in the region 230a is released, as shown in Fig. 10(A). Thereafter, the pushing pin 251 of the pushing unit 250 descends to push down the center of the upper wafer W1, thereby bringing the upper wafer W1 into contact with the lower wafer W2 (step S113). As a result, the centers of the upper wafer W1 and the lower wafer W2 are bonded together.

[0071] Because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been modified, van der Waals forces (intermolecular forces) are generated between the bonding surfaces W1j and W2j, bonding the bonding surfaces W1j and W2j together. Furthermore, because the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 have been hydrophilized, hydrophilic groups (e.g., OH groups) form hydrogen bonds, firmly bonding the bonding surfaces W1j and W2j together.

[0072] Next, the control device 90 stops the operation of the vacuum pump 241b, and releases the vacuum suction of the upper wafer W1 in the region 230b as shown in Fig. 10(B). Subsequently, the control device 90 stops the operation of the vacuum pump 241c, and releases the vacuum suction of the upper wafer W1 in the region 230c as shown in Fig. 10(C).

[0073] In this way, the vacuum suction of the upper wafer W1 is gradually released from the center toward the periphery of the upper wafer W1, and the upper wafer W1 gradually drops and contacts the lower wafer W2. Then, the bonding of the upper wafer W1 and the lower wafer W2 progresses sequentially from the center toward 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 contact each other over their entire surfaces, the upper wafer W1 and the lower wafer W2 are bonded, and a bonded wafer T is obtained. Thereafter, the bonding apparatus 1 raises the pushing pin 251 to its original position.

[0074] After the bonded wafer T is formed, the control device 90 causes the moving mechanism 290 to move the relative positions of the upper chuck 230 and the lower chuck 231 from the bonding position shown in Fig. 7 to the substrate transfer position shown in Fig. 5 and Fig. 6 (step S115). For example, the moving mechanism 290 first lowers the lower chuck 231 to widen the vertical gap between the lower chuck 231 and the upper chuck 230. Next, the moving mechanism 290 moves the lower chuck 231 laterally to laterally shift the lower chuck 231 and the upper chuck 230.

[0075] Thereafter, the control device 90 causes the transfer device 61 to transfer the bonded wafer T out of the bonding module 41 (step S116). Specifically, first, the lower chuck 231 releases the bonded wafer T. Next, the multiple holding pins 265 rise and transfer the bonded wafer T to the transfer device 61. Thereafter, the multiple holding pins 265 descend to their original positions.

[0076] 11, the bonding apparatus 1 described above has a plurality of displacement sensors 270 on the upper chuck 230 that measure the height position of the upper wafer W1 in order to monitor the progress of bonding between the upper wafer W1 and the lower wafer W2. The displacement sensors 270 are optical sensors that irradiate the upper wafer W1 with measurement light and obtain measurement information by receiving light reflected from the upper wafer W1. Furthermore, the bonding apparatus 1 has a gas supply mechanism 280 around the upper chuck 230 that supplies a void-reducing gas near the outer edges of the upper wafer W1 and the lower wafer W2 during bonding.

[0077] The multiple displacement sensors 270 are arranged, for example, at three different radial positions radially outward from the center of the upper chuck 230, and are arranged at equal intervals along the circumferential direction at the same radial positions. As an example, three displacement sensors 270 at different radial positions are provided in each of areas 230a, 230b, and 230c set in the upper chuck 230. Hereinafter, the displacement sensor 270 located in area 230a will also be referred to as an inner displacement sensor 270a, the displacement sensor 270 located in area 230b will also be referred to as an intermediate displacement sensor 270b, and the displacement sensor 270 located in area 230c will also be referred to as an outer displacement sensor 270c.

[0078] Each displacement sensor 270 (inner displacement sensor 270a, middle displacement sensor 270b, and outer displacement sensor 270c) is installed to face the upper wafer W1 held by the upper chuck 230. The upper chuck 230 has an arrangement portion 275 for arranging each displacement sensor 270. The arrangement portion 275 includes a recess 276 that accommodates part or all of the displacement sensor 270, a fixing portion 277 that fixes the displacement sensor 270, and an aperture 278 that connects the recess 276 to a space on the chucking surface side of the upper chuck 230. Each fixing portion 277 fixes each displacement sensor 270 so that the tips (lower ends) of the displacement sensors 270 are at the same height. The aperture 278 is formed through the bottom of the recess 276 and tapers toward the chucking surface, thereby narrowing the range of the measurement light of the displacement sensor 270.

[0079] 12, each displacement sensor 270 arranged in the arrangement unit 275 can measure the distance to the surface (non-bonding surface W1n) of the upper wafer W1 facing the displacement sensor 270 via the space from the tip of the displacement sensor 270 to the upper wafer W1. In other words, the space from the tip of the displacement sensor 270 to the non-bonding surface W1n of the upper wafer W1 forms a measurement optical path of the displacement sensor 270. Furthermore, the displacement sensor 270 is communicably connected to the control device 90, and transmits acquired information to the control device 90 under command of the control device 90 or automatically. The control device 90 functions as a processing unit that processes information from each displacement sensor 270.

[0080] Each displacement sensor 270 may be, for example, a white light confocal sensor that emits white (multicolor) measurement light toward the upper wafer W1 and measures distance using information about the light reflected from the surface (non-bonding surface W1n) of the upper wafer W1. The white light confocal displacement sensor 270 includes a housing 271, a white LED 272, and a lens module 273 that focuses the measurement light emitted from the white LED 272 for each color (each of multiple wavelengths) at different positions on the optical axis. The lens module 273 may include multiple types of lenses 273a, 273b arranged in the longitudinal direction of the displacement sensor 270. The white light confocal displacement sensor 270 also includes a measuring device (not shown) that disperses the reflected light and measures its spectrum (reflection spectrum).

[0081] For example, the displacement sensor 270 sets the focal length of blue light to the farthest position, the focal length of red light to the closest position, and the focal length of green light to be set somewhere in between. Light of a color (wavelength) focused on the upper surface of the upper wafer W1 is most strongly reflected. Therefore, the displacement sensor 270 can measure the relative distance between the displacement sensor 270 and the upper wafer W1 based on the peak wavelength of the reflection spectrum. The order and distance of the focal positions of the red, green, and blue light are not particularly limited and may be set arbitrarily depending on the device to be used. By using a white light confocal displacement sensor 270 in this way, the displacement sensor 270 does not need to come into contact with the upper wafer W1 during measurement and can achieve high measurement accuracy. However, the displacement sensor 270 is not limited to a confocal sensor; various optical sensors, such as a spectral interference sensor or a triangulation sensor, may also be used.

[0082] 11 and 12, the gas supply mechanism 280 includes a gas discharge unit 281 and a supply unit 282. The gas discharge unit 281 is formed, for example, in a circular ring shape that surrounds the side of the circumferential surface of the upper chuck 230. The gas discharge unit 281 has a plurality of discharge ports 281a evenly spaced along the circumferential direction. The surface of the gas discharge unit 281 that has the discharge ports 281a is an inclined surface that can guide gas between the upper wafer W1 and the lower wafer W2. The gas discharge unit 281 can discharge gas approximately evenly between the upper wafer W1 and the lower wafer W2 and near their outer edges along the circumferential direction.

[0083] The supply unit 282 includes a supply path 283 connected to the gas discharge unit 281, and a gas source 284 provided at the upstream end of the supply path 283. The supply unit 282 may also include, at a midpoint of the supply path 283, an opening / closing valve for opening and closing the flow path of the supply path 283, a flow regulator for adjusting the flow rate of the gas, and the like (both not shown).

[0084] The gases discharged by the gas supply mechanism 280 include a condensation-suppressing gas for suppressing condensation between the upper wafer W1 and the lower wafer W2, or a gas with a smaller molecular size than air (nitrogen (N2) gas, oxygen (O2) gas), etc. These gases are intended to reduce edge voids, which are defects at the bonding interface that occur near the outer edges of the upper wafer W1 and the lower wafer W2, and are hereinafter also referred to as void-reducing gases.

[0085] Examples of void-reducing gases include noble gases such as helium (He) gas, neon (Ne) gas, and argon (Ar) gas, or hydrogen (H2) gas, or a combination of these gases. These gases have smaller molecular sizes than nitrogen gas and oxygen gas, and have a strong Joule-Thomson effect, making them highly effective in suppressing condensation. Void-reducing gases are also low-humidity gases that do not contain moisture (or have moisture content reduced as much as possible).

[0086] The supply unit 282 according to the embodiment is configured to supply helium gas as a void-reducing gas to the gas discharge unit 281. The gas supply mechanism 280 may be configured to include multiple supply paths 283 and gas sources 284, etc., and to selectively supply multiple types of gases to the gas discharge unit 281 at different times. For example, the gas supply mechanism 280 may be configured to supply a low-humidity gas at a first time, such as before the start of bonding, and to supply a void-reducing gas that is a different gas from the low-humidity gas at a second time, such as during the bonding process.

[0087] Incidentally, the void-reducing gas discharged by the gas supply mechanism 280 may enter the measurement optical path of the arrangement portion 275 provided in the upper chuck 230 or the housing 271 of the displacement sensor 270. The void-reducing gas that has entered the measurement optical path changes the refractive index of the measurement light and reflected light of the displacement sensor 270. In particular, as shown in FIG. 12 , each outer displacement sensor 270c is disposed adjacent to the gas supply mechanism 280 to measure the height position of the outer edge of the upper wafer W1. Therefore, the void-reducing gas discharged by the gas discharge portion 281 of the gas supply mechanism 280 relatively easily enters the measurement optical path, such as the recess 276 or aperture 278 of the arrangement portion 275 where the outer displacement sensor 270c is disposed.

[0088] The refractive index of light changes due to the void-reducing gas, resulting in a deviation in the measurement value of the outer displacement sensor 270c. As an example, when helium gas is used as the void-reducing gas, the refractive index of helium gas is 1.000035. On the other hand, the refractive index of air without helium gas is 1.000292. The distance of the measurement optical path from the displacement sensor 270 to the upper wafer W1 is set to, for example, 10 mm, and the deviation between the measurement value when this measurement optical path is filled with air and the measurement value when it is filled with helium gas is calculated. This deviation is 10 mm × (1.000292 - 1.000035) = 0.00257 mm = 2.57 μm.

[0089] Such deviation in the measurement value can cause the displacement of the upper wafer W1 to be lost when the upper wafer W1 is released from the upper chuck 230 during bonding of the upper wafer W1 and the lower wafer W2. In particular, changes in the measurement value of the displacement sensor 270 are affected by the amount and timing of the inflow of the void-reducing gas. It can be said that it is difficult for the control device 90 to determine, by simply monitoring the measurement value, whether the upper wafer W1 has actually been displaced or whether the void-reducing gas has been flown in without the upper wafer W1 being displaced.

[0090] Therefore, in the bonding apparatus 1 according to the embodiment, a transparent member 279, which serves as a reference member when measuring the height position of the upper wafer W1, is installed in the placement unit 275. In optical measurement using the displacement sensor 270, the bonding apparatus 1 acquires the reference member-wafer distance between the transparent member 279 and the upper wafer W1, and monitors changes in the height position of the upper wafer W1 based on this reference member-wafer distance.

[0091] Specifically, the transparent member 279 is formed to be thinner than the thickness of the aperture 278, and is disposed at the lower end position of the aperture 278 where the opening area is the smallest. The lower end opening of the aperture 278 is continuous with the pipe installation bottom surface from which the ribs 230r protrude. The transparent member 279 is, for example, fitted into the inner peripheral surface at the lower end position of the aperture 278, and is firmly (non-displaceably) fixed to the upper chuck 230 so as to be continuous and flush with the pipe installation bottom surface.

[0092] The transparent member 279 is light transmissive and has a reference surface 279a facing the upper wafer W1 and an opposite surface 279b facing the displacement sensor 270. In a state in which the upper wafer W1 is attracted and held before bonding, the distance between the reference surface 279a of the transparent member 279 and the non-bonding surface W1n of the upper wafer W1, i.e., the reference member-wafer distance, is preferably set in the range of approximately 0 mm to 5 mm. In this embodiment, the upper chuck 230 attracts the upper wafer W1 via a plurality of ribs 230r, so that the reference member-wafer distance in the held state is approximately 0.25 mm.

[0093] The material of the transparent member 279 may be a transparent resin material or an inorganic material such as quartz or ceramics. The light transmittance of the transparent member 279 is preferably 100%, but may be lower than 100%.

[0094] 13, the displacement sensor 270 and arrangement unit 275 described above can acquire a reflection spectrum of the measurement light that has passed through the transparent member 279 and is reflected off the non-bonding surface W1n of the upper wafer W1, and a reflection spectrum of the measurement light that has been reflected off the reference surface 279a of the transparent member 279. The shift in the peak wavelength of the light intensity of each reflection spectrum corresponds to the positions of the transparent member 279 and the upper wafer W1. Therefore, the displacement sensor 270 can calculate the reference member-wafer distances of the reference surface 279a and the non-bonding surface W1n based on the reflection spectrum (light intensity, wavelength) that is the measurement information.

[0095] The bonding apparatus 1 can be configured such that a control board provided in the displacement sensor 270 calculates the reference member-wafer distance from the measured reflection spectrum and transmits the measurement information to the control device 90. Alternatively, the bonding apparatus 1 may obtain measurement information of the reflection spectrum using the displacement sensor 270, transmit the measurement information to the control device 90, and calculate the reference member-wafer distance in the control device 90. In either case, the control device 90 can obtain the reference member-wafer distance.

[0096] As described above, the displacement sensor 270, the placement unit 275 including the transparent member 279, and the control device 90 constitute a measuring device that measures the position of the upper wafer W1, which is a substrate. The measuring device can accurately detect the position of the substrate by using the distance between the reference member and the wafer in measurements by the displacement sensor 270. The significance of the measuring device monitoring the height position of the upper wafer W1 using the distance between the reference member and the wafer will be described below with reference to FIGS. 14(A) to 14(D).

[0097] 14(A), the measurement device that calculates the sensor-wafer distance in measurement by the displacement sensor 270' monitors the distance of the entire measurement optical path DL from the displacement sensor 270' to the upper wafer W1. In this case, when helium gas (void-reducing gas) flows into the measurement optical path DL as shown in FIG. 14(B), the refractive index of the entire measurement optical path DL changes.

[0098] Because the refractive index of the entire measurement optical path DL changes in this way, the refractive index significantly affects the calculated sensor-to-wafer distance. For example, as shown in Figure 14(B), the void-reducing gas causes the measured sensor-to-wafer distance to be shifted, either shortened or lengthened. Therefore, the measurement device according to the reference example has difficulty distinguishing between a change in the measurement value due to the displacement of the upper wafer W1 and a change in the measurement value due to the inflow of the void-reducing gas.

[0099] 14(C) calculates the reference member-wafer distance, which is the distance between the upper wafer W1 and the transparent member 279, in the measurement by the displacement sensor 270. In this case as well, as shown in FIG. 14(D), when helium gas flows between the displacement sensor 270 and the transparent member 279 and between the transparent member 279 and the upper wafer W1 in the measurement optical path DL, the refractive index of each changes.

[0100] However, in the embodiment, both the position of the transparent member 279 measured by the displacement sensor 270 and the position of the upper wafer W1 will shift as the refractive index of the measurement optical path DL between the displacement sensor 270 and the transparent member 279 changes. In other words, even if the refractive index of the measurement optical path DL between the displacement sensor 270 and the transparent member 279 changes, the relative positions of the transparent member 279 and the upper wafer W1 measured by the displacement sensor 270 will not shift.

[0101] Note that the change in the refractive index between the transparent member 279 and the upper wafer W1 due to the inflow of the void-reducing gas causes a shift in the relative position between the transparent member 279 and the upper wafer W1. However, as described above, the reference member-wafer distance in the held state is approximately 0.25 mm, which is only a small percentage of the total length of the measurement optical path DL. For example, if the total length of the measurement optical path DL is set to 10 mm, this percentage is 0.25%. In other words, even if the refractive index between the transparent member 279 and the upper wafer W1 changes, the shift in the relative position between the transparent member 279 and the upper wafer W1 is only slight. Therefore, by monitoring the reference member-wafer distance, the control device 90 can easily distinguish between a change in the measurement value due to the displacement of the upper wafer W1 and a change in the measurement value due to the inflow of the void-reducing gas.

[0102] For the above reasons, when installing the transparent member 279 in the measurement optical path DL, it is desirable to install the transparent member 279 so that the ratio of the distance between the reference member and the wafer to the overall length of the measurement optical path DL is as small as possible. For example, the ratio of the distance between the reference member and the wafer to the overall length of the measurement optical path DL is preferably set to 5% or less (0% to 5%), and more preferably 1% or less.

[0103] As shown in FIG. 11 , the bonding apparatus 1 provides the transparent member 279 only for the outer displacement sensors 270c, which are located closer to the gas supply mechanism 280, in the measurement optical path DL. In other words, the bonding apparatus 1 does not provide the transparent member 279 for the inner displacement sensors 270a and the middle displacement sensors 270b, which are located radially inward of the outer displacement sensors 270c. This is because the amount of void-reducing gas supplied near the outer edges of the upper wafer W1 and the lower wafer W2 that enters the measurement optical path DL of the inner displacement sensors 270a and the middle displacement sensors 270b is small. This allows the bonding apparatus 1 to reduce manufacturing costs and man-hours. Therefore, the control device 90 calculates the sensor-to-wafer distance for each inner displacement sensor 270a and each middle displacement sensor 270b. In this way, the control device 90 can monitor the height position of the upper wafer W1 in the same manner simply by changing the calculation method (reference member-wafer distance, sensor-wafer distance) depending on the presence or absence of the transparent member 279. However, it goes without saying that the bonding device 1 may also be configured to acquire the reference member-wafer distance by installing the transparent members 279 also on each of the inner displacement sensors 270a and each of the intermediate displacement sensors 270b.

[0104] The bonding apparatus 1 according to the embodiment is basically configured as described above, and the bonding process of the upper wafer W1 and the lower wafer W2, including the measurement method, will be described below with reference to Fig. 15. In bonding the upper wafer W1 and the lower wafer W2, the control device 90 sequentially executes the process flow of steps S121 to S127 in Fig. 15, for example.

[0105] The control device 90 performs a step of sucking and holding the upper wafer W1 by the upper chuck 230 (step S121). Step S121 corresponds to a part of step S111 in FIG.

[0106] Thereafter, the control device 90 measures the height position of the upper wafer W1 in the held state using each displacement sensor 270 (step S122). At this time, because the gas supply mechanism 280 is not supplying a void-reducing gas, air is present in the measurement optical path DL of each displacement sensor 270. Each displacement sensor 270 can accurately measure the height position of the upper wafer W1 in the held state through the air. Note that the gas supply mechanism 280 may promote low humidity by supplying low-humidity gas between the upper wafer W1 and the lower wafer W2 before pushing down the upper wafer W1.

[0107] For example, in the measurement by the displacement sensor 270, as described above, the upper wafer W1 is irradiated with measurement light and the light reflected from the upper wafer W1 and the light reflected from the transparent member 279 are received. Then, the control device 90 acquires the reference member-wafer distance between the upper wafer W1 and the transparent member 279 based on the measurement information of the displacement sensor 270, and performs a process of recognizing the height position of the upper wafer W1.

[0108] Next, the pushing unit 250 of the bonding apparatus 1 lowers the pushing pin 251 to push down the center of the upper wafer W1 (step S123). This starts bonding the upper wafer W1 and the lower wafer W2. This step S123 corresponds to step S113 in FIG. 8.

[0109] When bonding starts, the control device 90 measures the height position of the displacing upper wafer W1 using each displacement sensor 270 (step S124). As described above, bonding of the upper wafer W1 and the lower wafer W2 progresses from the center to the outside in the radial direction. Therefore, the control device 90 can monitor the progress of bonding of the upper wafer W1 and the lower wafer W2 mainly by using the measurement value of the intermediate displacement sensor 270b.

[0110] The control device 90 determines the timing to supply void-reducing gas from the gas supply mechanism 280 during the bonding process of the upper wafer W1 and the lower wafer W2 (step S125). For example, the control device 90 monitors the measurement values ​​of each intermediate displacement sensor 270b and determines the supply of void-reducing gas from the gas supply mechanism 280 at the timing when the upper wafer W1 is lowered as measured by each intermediate displacement sensor 270b. If the descent of the upper wafer W1 has not reached the intermediate displacement sensor 270b (step S125: NO), the process returns to step S123 and repeats the same process flow. On the other hand, if the descent of the upper wafer W1 has reached the intermediate displacement sensor 270b (step S125: YES), the void-reducing gas is supplied from the gas supply mechanism 280. This allows the bonding apparatus 1 to suppress the generation of voids at the outer edges of the upper wafer W1 and the lower wafer W2.

[0111] Also, when the void-reducing gas is supplied, the control device 90 measures the height position of the displacing upper wafer W1 using each displacement sensor 270 (step S126). In particular, when the void-reducing gas is supplied, the bonding of the upper wafer W1 and the lower wafer W2 has reached the vicinity of the outer edges, and the control device 90 monitors the measurement value of the outer displacement sensor 270c to recognize the progress of the bonding of the upper wafer W1 and the lower wafer W2.

[0112] 14(D), each outer displacement sensor 270c measures the height position of the upper wafer W1, in other words, the reference member-wafer distance, through the transparent member 279. Therefore, even if the refractive index of the measurement optical path DL changes due to the void-reducing gas, the control device 90 can stably acquire the reference member-wafer distance while suppressing deviation caused by the change in refractive index.

[0113] Therefore, the control device 90 determines whether bonding of the upper wafer W1 and the lower wafer W2 is complete based on the measurement information of each outer displacement sensor 270c (step S127). If bonding of the upper wafer W1 and the lower wafer W2 is continuing (step S127: NO), the process returns to step S125 and repeats the same process flow. On the other hand, if bonding of the upper wafer W1 and the lower wafer W2 is complete (step S127: YES), the process proceeds to step S128.

[0114] In step S128, control device 90 controls gas supply mechanism 280 to stop supplying the void-reducing gas, and also controls a carry-out process for carrying out the formed bonded wafer T. The carry-out process for the bonded wafer T corresponds to steps S115 and S116 in FIG.

[0115] As described above, the bonding apparatus 1 and the measuring apparatus according to the embodiment include the transparent member 279 between the upper wafer W1 and the displacement sensor 270, and acquire the reference member-wafer distance between the upper wafer W1 and the transparent member 279. This allows the control device 90 to appropriately recognize the position of the upper wafer W1 based on its relative position with respect to the transparent member 279. Furthermore, the displacement sensor 270 or the control device 90 can easily and accurately acquire the distance between the upper wafer W1 and the transparent member 279 by using measurement information of the reflection spectrum.

[0116] In particular, when the measurement device is applied to the bonding device 1, it becomes possible to effectively monitor the progress of bonding of the upper wafer W1 and the lower wafer W2. That is, the control device 90 can effectively recognize the displacement of the upper wafer W1 relative to the upper chuck 230 by obtaining the reference member-to-wafer distance of the upper wafer W1 held on the upper chuck 230 and the reference member-to-wafer distance of the upper wafer W1 released from the upper chuck 230. In this way, the bonding device 1 and the measurement device can accurately recognize the position of the displacing substrate by using the reference member-to-wafer distance between the upper wafer W1 and the transparent member 279, even when the state (refractive index) of the gas in the measurement optical path DL does not change.

[0117] Furthermore, even when the void-reducing gas flows into the measurement optical path DL by supplying the void-reducing gas from the gas supply mechanism 280, the bonding apparatus 1 can continue to stably measure the height position of the upper wafer W1 by suppressing deviations in the measurement value due to the reference member-wafer distance. Moreover, the bonding apparatus 1 acquires the reference member-wafer distance by installing the transparent member 279 on the outer displacement sensor 270c, while not installing the transparent member 279 on the inner displacement sensor 270a and the intermediate displacement sensor 270b, thereby making it possible to reduce manufacturing costs and manufacturing man-hours.

[0118] Furthermore, by calculating the distance between the reference surface 279a of the transparent member 279 and the non-bonding surface W1n of the upper wafer W1 as the reference member-wafer distance, the bonding apparatus 1 can shorten the distance between the upper wafer W1 and the transparent member 279 as much as possible and reduce measurement errors. For example, by setting the ratio of the reference member-wafer distance to the measurement optical path DL to 5% or less, it is possible to sufficiently suppress positional deviations in the measurement results even if gas flows between the upper wafer W1 and the transparent member 279 and the refractive index changes. Furthermore, by placing the transparent member 279 in the aperture 278, the bonding apparatus 1 can easily and firmly fix the transparent member 279.

[0119] The bonding apparatus 1, the measuring apparatus, and the measuring method of the present disclosure are not limited to the above-described embodiments, and various modifications are possible. For example, the bonding apparatus 1 is not limited to a configuration in which the displacement sensor 270, which is an optical sensor, is installed only in the upper chuck 230, and the displacement sensor 270 (and the transparent member 279) may also be installed in the lower chuck 231.

[0120] Furthermore, for example, the displacement sensor 270 or the control device 90 is not limited to acquiring the distance between the reference surface 279a of the transparent member 279 and the non-bonding surface W1n of the upper wafer W1, but may also acquire the distance between the opposite surface 279b of the transparent member 279 and the non-bonding surface W1n of the upper wafer W1. Even in this case, the displacement sensor 270 or the control device 90 can accurately acquire the position of the transparent member 279 based on the light reflected by the opposite surface 279b.

[0121] The substrate processing apparatus to which the optical sensor (displacement sensor 270) and the transparent member 279 are applied is not limited to the bonding apparatus 1, and the optical sensor and the transparent member 279 may be applied to various apparatuses that use an optical sensor to measure the position of a substrate. For example, the optical sensor and the transparent member 279 may be applied to a separation apparatus, which is a substrate processing apparatus that separates the bonded wafer T into an upper wafer W1 and a lower wafer W2, to perform a similar process. Furthermore, even in a substrate processing apparatus that performs substrate processing by supplying gas into a processing vessel containing substrates, the optical sensor and the transparent member 279 described above may be applied to measure the position of the substrate to perform a similar process. Alternatively, the transparent member 279 may be applied to a measurement apparatus that attaches an optical sensor to the end effector of a transfer apparatus and measures the position of a substrate using the moving end effector, to perform a similar process.

[0122] The substrate processing apparatus, measuring apparatus, and measuring method according to the presently disclosed embodiments are illustrative in all respects and not restrictive. The embodiments can be modified and improved in various ways without departing from the spirit and scope of the appended claims. The matters described in the above embodiments can be configured in other ways as long as they are not inconsistent, and can be combined as long as they are not inconsistent. [Explanation of symbols]

[0123] 1 Bonding equipment 90 Control device 230 Upper chuck 270 Displacement Sensor 279 Transparent Materials DL measurement optical path W1 upper wafer W2 lower wafer

Claims

1. a holding portion that removably holds the substrate; an optical sensor provided in the holder, which irradiates measurement light onto the substrate and receives reflected light from the substrate; a transparent member that is disposed in a measurement optical path between the substrate and the optical sensor and that is capable of transmitting light; a processing unit that processes measurement information from the optical sensor, the processing unit acquires the distance between the substrate and the transparent member based on the measurement information and recognizes the position of the substrate. Substrate processing equipment.

2. the optical sensor or the processing unit acquires the distance between the substrate and the transparent member based on the spectrum of the reflected light included in the measurement information. The substrate processing apparatus according to claim 1 .

3. the processing unit acquires a distance between the substrate held by the holding unit and the transparent member, and also acquires a distance between the substrate released from the holding unit and the transparent member. The substrate processing apparatus according to claim 2 .

4. the holding portion includes a first holding portion that holds a first substrate that is the substrate, and a second holding portion that holds a second substrate that is the substrate at a position facing the first substrate, the substrate processing apparatus is a bonding apparatus that pushes out the first substrate from the first holding unit to bond the first substrate and the second substrate together, the processing unit recognizes a progress state of bonding between the first substrate and the second substrate based on the measurement information of the optical sensor provided in the first holding unit. The substrate processing apparatus according to claim 3 .

5. a gas supply mechanism that supplies a void-reducing gas to an outer edge between the first substrate and the second substrate before they are bonded; the optical sensor acquires the distance between the substrate and the transparent member in each of a state in which the void-reducing gas is not present in the measurement optical path and a state in which the void-reducing gas has entered the measurement optical path; The substrate processing apparatus according to claim 4 .

6. the gas supply mechanism is provided radially outward of the first holding part, the first holding unit includes a plurality of the optical sensors arranged along a radial direction of the substrate held by the first holding unit, The transparent member is provided on the radially outer optical sensor among the plurality of optical sensors in the radial direction. The substrate processing apparatus according to claim 5 .

7. the processing unit acquires the distance between the substrate and the transparent member based on the measurement information of the optical sensor on the radially outer side, and acquires the distance between the substrate and the optical sensor based on the measurement information of the optical sensor on the radially inner side. The substrate processing apparatus according to claim 6 .

8. the optical sensor or the processing unit calculates a distance between a surface of the substrate facing the transparent member and a surface of the transparent member facing the substrate; The substrate processing apparatus according to claim 1 .

9. the holding portion includes a placement portion on which the optical sensor is placed, the arrangement unit has an aperture that narrows the range of the measurement light in the measurement light path, and the transparent member is fixed to the aperture. The substrate processing apparatus according to claim 1 .

10. a ratio of a distance between the substrate and the transparent member to a total length of the measurement optical path is 5% or less; The substrate processing apparatus according to claim 1 .

11. The optical sensor is a confocal displacement sensor. The substrate processing apparatus according to claim 1 .

12. A measurement apparatus for measuring a position of a substrate, comprising: an optical sensor that irradiates measurement light onto the substrate, which is displaceable relative to the measurement device, and receives reflected light from the substrate; a transparent member that is disposed between the substrate and the optical sensor and that is capable of transmitting light; a processing unit that processes measurement information from the optical sensor, the processing unit acquires the distance between the transparent member and the substrate based on the measurement information and recognizes the position of the substrate. Measuring equipment.

13. A measurement method for measuring the position of a substrate, (A) a step of releasably holding a substrate by a holding portion; (B) irradiating the substrate with measurement light by an optical sensor provided in the holding unit, and receiving reflected light from the substrate and reflected light from a transparent member that is disposed in a measurement light path between the substrate and the optical sensor and is capable of transmitting light; (C) acquiring, in a processing unit, a distance between the substrate and the transparent member based on measurement information from the optical sensor, and recognizing a position of the substrate; Measurement method.

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