Distance measurement device, distance measurement method, joining device, and joining method

Abstract

To provide a technique capable of taking a distance measurement using a capacitive sensor even when the capacitive sensor and an object to be measured are not electrically conductive.SOLUTION: A distance measurement device comprises a first member and a capacitive sensor. The first member is arranged not in contact opposite an object to be measured which is a conductor or semiconductor. The capacitive sensor is provided to the first member, and detects the distance to the object to be measured. The first member is formed of a conductive member and the capacitive sensor is grounded through the first member.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a distance measuring device, a distance measuring method, a joining device, and a joining method. [Background technology]

[0002] 2. Description of the Related Art A bonding apparatus for bonding substrates such as semiconductor wafers together is known (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-147944 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that allows distance measurement using a capacitance sensor even when there is no electrical continuity between the capacitance sensor and an object to be measured. [Means for solving the problem]

[0005] A distance measurement device according to an embodiment of the present disclosure includes a first member and a capacitance sensor. The first member is disposed facing a measurement object, which is a conductor or a semiconductor, without contacting the first member. The capacitance sensor is provided on the first member and detects the distance between the measurement object and the measurement object. The first member is formed of a conductive member, and the capacitance sensor is grounded via the first member. Effect of the Invention

[0006] According to the present disclosure, distance measurement can be performed using a capacitance sensor even when there is no electrical continuity between the capacitance sensor and an object to be measured. [Brief description of the drawings]

[0007] [Figure 1]FIG. 1 is a schematic plan view showing the configuration of a joining system according to an embodiment. [Diagram 2] FIG. 2 is a schematic side view of the upper wafer and the lower wafer according to the embodiment. [Diagram 3] FIG. 3 is a schematic plan view showing the configuration of the bonding device according to the embodiment. [Figure 4] FIG. 4 is a schematic side view showing the configuration of the joining device according to the embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing an upper chuck and a lower chuck according to the embodiment. [Figure 6] FIG. 6 is a schematic diagram of the upper chuck as viewed from below. [Figure 7] FIG. 7 is an enlarged schematic view of a main body portion of the upper chuck, a sensor, and an upper wafer according to the embodiment. [Figure 8] FIG. 8 is a graph showing changes in the measurement values ​​of the sensors in FIG. [Figure 9] FIG. 9 is a flowchart illustrating a procedure of a process executed by the bonding system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a detailed description will be given of a distance measurement device, a distance measurement method, a joining device, and a joining method according to the present disclosure (hereinafter, referred to as "embodiments") with reference to the drawings. Note that the present disclosure is not limited to these embodiments. Furthermore, the embodiments can be appropriately combined as long as the processing contents are not contradictory. Furthermore, the same parts in the following embodiments are given the same reference numerals, and duplicated descriptions will be omitted.

[0009] In addition, in the embodiments described below, expressions such as "constant", "orthogonal", "vertical" and "parallel" may be used, but these expressions do not necessarily mean "constant", "orthogonal", "vertical" and "parallel" strictly. In other words, each of the above expressions allows for deviations due to, for example, manufacturing accuracy and installation accuracy.

[0010] In addition, in the drawings referred to below, for ease of understanding, an orthogonal coordinate system may be shown in which the X-axis, Y-axis, and Z-axis directions are defined as being orthogonal to each other, and the Z-axis positive direction is the vertically upward direction. Also, the direction of rotation about the vertical axis may be referred to as the θ direction.

[0011] When substrates are bonded together by intermolecular forces, pressing the center of one substrate into contact with the other substrate generates a bonding wave whose bonding area expands from the center of the substrate toward the periphery. In bonding devices, a process for measuring the progress of the bonding wave may be performed. For example, a sensor provided in a holder that holds the substrate by suction from above may be used to measure the distance from the holder to the substrate (measurement target) to measure the progress of the bonding wave. Accurate measurement of the progress of the bonding wave leads to improved bonding accuracy of the substrates.

[0012] Here, a method for accurately measuring the progress of the bonding wave can be considered to increase the number of sensors used to measure the distance between the holder and the substrate. For example, by using a capacitance sensor that is smaller than an optical displacement meter, the number of sensors used to measure the distance to the substrate can be increased.

[0013] However, when using a capacitance sensor, the object to be measured is usually a conductor and the capacitance sensor and the object to be measured are electrically conductive, but it is difficult to satisfy such requirements in a bonding device that bonds substrates together. Therefore, a technology is desired that can measure distances using a capacitance sensor even when there is no electrical continuity between the capacitance sensor and the object to be measured.

[0014] The above technology is expected to be applicable not only to the bonding device but also to other devices. In the following, an embodiment in which the distance measurement device and the distance measurement method according to the present disclosure are applied to the bonding device will be described, but the distance measurement device and the distance measurement method according to the present disclosure can be applied to devices other than the bonding device.

[0015] <Configuration of the joining system> First, the configuration of a bonding system 1 according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a schematic plan view showing the configuration of the bonding system 1 according to an embodiment. Fig. 2 is a schematic side view of an upper wafer W1 and a lower wafer W2 according to an embodiment.

[0016] The bonding system 1 shown in FIG. 1 forms a laminated wafer T by bonding a first substrate W1 and a second substrate W2 together.

[0017] The first substrate W1 and the second substrate W2 are semiconductor substrates such as silicon wafers, compound semiconductor wafers, etc. The first substrate W1 and the second substrate W2 have approximately the same diameter.

[0018] Hereinafter, the first substrate W1 will be referred to as the "upper wafer W1," and the second substrate W2 will be referred to as the "lower wafer W2." In other words, the upper wafer W1 is an example of the first substrate, and the lower wafer W2 is an example of the second substrate. Furthermore, the upper wafer W1 and the lower wafer W2 may be collectively referred to as "wafer W."

[0019] 2, of the surfaces of the upper wafer W1, the surface to be bonded to the lower wafer W2 will be referred to as a "bonding surface W1j," and the surface opposite the bonding surface W1j will be referred to as a "non-bonding surface W1n." Also, of the surfaces of the lower wafer W2, the surface to be bonded to the upper wafer W1 will be referred to as a "bonding surface W2j," and the surface opposite the bonding surface W2j will be referred to as a "non-bonding surface W2n."

[0020] 1, the bonding system 1 includes a loading / unloading station 2 and a processing station 3. The loading / unloading station 2 and the processing station 3 are arranged in the positive direction of the X-axis in the order of the loading / unloading station 2 and the processing station 3. The loading / unloading station 2 and the processing station 3 are connected together.

[0021] The loading / unloading station 2 includes a mounting table 10 and a transfer area 20. The mounting table 10 includes a plurality of mounting plates 11. Cassettes C1, C2, and C3, each of which stores a plurality of substrates (e.g., 25 substrates) in a horizontal state, are placed on each of the mounting plates 11. For example, the cassette C1 is a cassette that stores an upper wafer W1, the cassette C2 is a cassette that stores a lower wafer W2, and the cassette C3 is a cassette that stores a laminated wafer T.

[0022] The transport area 20 is disposed adjacent to the mounting table 10 on the positive side in the X-axis direction. In the transport area 20, a transport path 21 extending in the Y-axis direction and a transport device 22 movable along the transport path 21 are provided.

[0023] The transfer device 22 is movable not only in the Y-axis direction but also in the X-axis direction and rotatable around the Z-axis. The transfer device 22 transfers the upper wafer W1, the lower wafer W2, and the overlapped wafer T between the cassettes C1 to C3 placed on the mounting plate 11 and a third processing block G3 of the processing station 3, which will be described later.

[0024] The number of cassettes C1 to C3 placed on the placement plate 11 is not limited to that shown in the figure. In addition to the cassettes C1, C2, and C3, a cassette for recovering defective substrates may be placed on the placement plate 11.

[0025] In the processing station 3, a plurality of processing blocks equipped with various devices, for example, three processing blocks G1, G2, and G3, are provided. For example, a first processing block G1 is provided on the front side (negative Y-axis side in FIG. 1) of the processing station 3, and a second processing block G2 is provided on the rear side (positive Y-axis side in FIG. 1) of the processing station 3. In addition, a third processing block G3 is provided on the loading / unloading station 2 side of the processing station 3 (negative X-axis side in FIG. 1).

[0026] In the first processing block G1, a surface modification device 30 is disposed that modifies the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2. The surface modification device 30 modifies the bonding surfaces W1j, W2j by cutting the bonds of SiO2 on the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 to single-bonded SiO, thereby making the bonding surfaces W1j, W2j more likely to be hydrophilized thereafter.

[0027] The first processing block G1 also includes a surface hydrophilizing device 40. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j, W2j of the upper wafer W1 and the lower wafer W2 with, for example, pure water, and cleans the bonding surfaces W1j, W2j.

[0028] In the surface hydrophilization device 40, 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 supplied onto the upper wafer W1 or the lower wafer W2 spreads over the bonding surfaces W1j, W2j of the upper wafer W1 or the lower wafer W2, making the bonding surfaces W1j, W2j hydrophilic.

[0029] Here, an example is shown in which the surface modification apparatus 30 and the surface hydrophilization apparatus 40 are arranged side by side, but the surface hydrophilization apparatus 40 may be stacked above or below the surface modification apparatus 30.

[0030] The second processing block G2 is also provided with a bonding device 41. The bonding device 41 bonds the hydrophilized upper wafer W1 and lower wafer W2 together by intermolecular forces. The bonding device 41 will be described in detail later.

[0031] In the third processing block G3, a transition (TRS) device (not shown) for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is provided.

[0032] 1, a transfer region 60 is formed in an area surrounded by the first processing block G1, the second processing block G2, and the third processing block G3. A transfer device 61 is disposed in the transfer region 60. The transfer device 61 has a transfer arm that is movable, for example, in the vertical direction, the horizontal direction, and around the vertical axis.

[0033] The transfer device 61 moves within the transfer region 60 to transfer the upper wafer W1, the lower wafer W2, and the overlapped wafer T to given devices within the first processing block G1, the second processing block G2, and the third processing block G3 adjacent to the transfer region 60.

[0034] The bonding system 1 also includes a control device 70. The control device 70 controls the operation of the bonding system 1. The control device 70 is, for example, a computer, and includes a control unit 71 and a storage unit 72. The control unit 71 includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), an input / output port, and various circuits. The CPU of the microcomputer realizes the control described below by reading and executing a program stored in the ROM. The storage unit 72 is realized by, for example, a semiconductor memory element such as a RAM or a flash memory, or a storage device such as a hard disk or an optical disk.

[0035] Such a program may be recorded on a computer-readable recording medium and installed from the recording medium into the storage unit 72 of the control device 70. Examples of computer-readable recording media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnet optical disk (MO), and a memory card.

[0036] <Configuration of the joining device> Next, the configuration of the joining device 41 will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a schematic plan view showing the configuration of the joining device 41 according to the embodiment, and Fig. 4 is a schematic side view showing the configuration of the joining device 41 according to the embodiment.

[0037] 3, the bonding apparatus 41 has a processing container 190 whose interior can be sealed. A loading / unloading port 191 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is formed on a side surface of the processing container 190 on the transfer region 60 side, and an opening / closing shutter 192 is provided at the loading / unloading port 191.

[0038] The inside of the processing vessel 190 is divided into a transfer region T1 and a processing region T2 by an inner wall 193. The above-mentioned loading / unloading port 191 is formed on a side surface of the processing vessel 190 in the transfer region T1. In addition, a loading / unloading port 194 for the upper wafer W1, the lower wafer W2, and the overlapped wafer T is also formed in the inner wall 193.

[0039] In the transfer region T1, a transition 200, a substrate transfer mechanism 201, a reversing mechanism 220, and a position adjustment mechanism 210 are arranged, for example, from the load / unload port 191 side in this order.

[0040] The transition 200 temporarily holds the upper wafer W1, the lower wafer W2, and the overlapped wafer T. The transition 200 is formed, for example, in two stages, and any two of the upper wafer W1, the lower wafer W2, and the overlapped wafer T can be held simultaneously.

[0041] The substrate transfer mechanism 201 has a transfer arm that is movable, for example, in the vertical direction (Z-axis direction), horizontal direction (Y-axis direction, X-axis direction), and direction around the vertical axis (θ direction). The substrate transfer mechanism 201 can transfer the upper wafer W1, the lower wafer W2, and the overlapped wafer T within the transfer region T1 or between the transfer region T1 and the processing region T2.

[0042] The position adjustment mechanism 210 adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2. Specifically, the position adjustment mechanism 210 has a base 211 equipped with a holding unit (not shown) that holds and rotates the upper wafer W1 and the lower wafer W2, and a detection unit 212 that detects the positions of the notch portions of the upper wafer W1 and the lower wafer W2. The position adjustment mechanism 210 adjusts the positions of the notch portions by detecting the positions of the notch portions of the upper wafer W1 and the lower wafer W2 using the detection unit 212 while rotating the upper wafer W1 and the lower wafer W2 held on the base 211. This adjusts the horizontal orientation of the upper wafer W1 and the lower wafer W2.

[0043] The inversion mechanism 220 inverts the upper wafer W1. Specifically, the inversion mechanism 220 has a holding arm 221 that holds the upper wafer W1. The holding arm 221 extends in the horizontal direction (X-axis direction). In addition, the holding arm 221 is provided with holding members 222 that hold the upper wafer W1 at, for example, four locations.

[0044] The holding arm 221 is supported by a drive unit 223 equipped with, for example, a motor. The holding arm 221 is rotatable about a horizontal axis by the drive unit 223. The holding arm 221 is also rotatable about the drive unit 223 and is movable in the horizontal direction (X-axis direction). Another drive unit (not shown) equipped with, for example, a motor is provided below the drive unit 223. The drive unit 223 can move in the vertical direction along a support column 224 extending in the vertical direction by the other drive unit.

[0045] In this manner, the upper wafer W1 held by the holding member 222 can be rotated around the horizontal axis and moved in the vertical and horizontal directions by the driving unit 223. In addition, the upper wafer W1 held by the holding member 222 can be rotated around the driving unit 223 and moved between the position adjustment mechanism 210 and the upper chuck 230 described later.

[0046] In the processing region T2, there are provided an upper chuck 230 that suction-holds the upper surface (non-bonding surface W1n) of the upper wafer W1 from above, and a lower chuck 231 that suction-holds the lower surface (non-bonding surface W2n) of the lower wafer W2 from below. The lower chuck 231 is disposed below the upper chuck 230 and configured to be able to be disposed opposite the upper chuck 230. The upper chuck 230 and the lower chuck 231 are, for example, vacuum chucks. The upper chuck 230 is an example of a first holding part, and the lower chuck 231 is an example of a second holding part. The specific configurations of the upper chuck 230 and the lower chuck 231 will be described later.

[0047] 4, the upper chuck 230 is supported by a support member 270 provided above the upper chuck 230. The support member 270 is fixed to a ceiling surface of the processing vessel 190 via a plurality of support columns 271, for example.

[0048] An upper imaging unit 235 is provided on the side of the upper chuck 230 to image the upper surface (bonding surface W2j) of the lower wafer W2 held by the lower chuck 231. The upper imaging unit 235 may be, for example, a CCD camera.

[0049] The lower chuck 231 is supported by a first moving unit 250 provided below the lower chuck 231. The first moving unit 250 moves the lower chuck 231 in the horizontal direction (X-axis direction) as described below. In addition, the first moving unit 250 is configured to be capable of moving the lower chuck 231 in the vertical direction and to be rotatable around a vertical axis.

[0050] The first moving part 250 is provided with a lower imaging part 236 that images the lower surface (bonding surface W1j) of the upper wafer W1 held by the upper chuck 230. For example, a CCD camera is used for the lower imaging part 236. The lower imaging part 236 is an example of an imaging part.

[0051] The first moving part 250 is attached to a pair of rails 252, 252. The pair of rails 252, 252 are provided on the lower surface side of the first moving part 250 and extend in the horizontal direction (X-axis direction). The first moving part 250 is configured to be movable along the rails 252.

[0052] The pair of rails 252, 252 are disposed on the second moving part 253. The second moving part 253 is attached to a pair of rails 254, 254. The pair of rails 254, 254 are disposed on the lower surface side of the second moving part 253 and extend in the horizontal direction (Y-axis direction). The second moving part 253 is configured to be movable in the horizontal direction (Y-axis direction) along the rails 254. The pair of rails 254, 254 are disposed on a mounting table 255 provided on the bottom surface of the processing vessel 190.

[0053] The first moving unit 250, the second moving unit 253, etc. configure a position adjustment unit 256. The position adjustment unit 256 adjusts the horizontal position of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 by moving the lower chuck 231 in the X-axis direction, the Y-axis direction, and the θ direction. In addition, the position adjustment unit 256 adjusts the vertical position of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 by moving the lower chuck 231 in the Z-axis direction.

[0054] Although the lower chuck 231 is moved in the X-axis direction, the Y-axis direction, and the θ-direction here, the position adjustment unit 256 may, for example, move the lower chuck 231 in the X-axis direction and the Y-axis direction and move the upper chuck 230 in the θ-direction. Also, although the lower chuck 231 is moved in the Z-axis direction here, the position adjustment unit 256 may, for example, move the upper chuck 230 in the Z-axis direction.

[0055] Next, the configurations of the upper chuck 230 and the lower chuck 231 will be described with reference to Fig. 5. Fig. 5 is a schematic diagram showing the upper chuck 230 and the lower chuck 231 according to the embodiment. Fig. 6 is a schematic diagram of the upper chuck 230 as viewed from below.

[0056] As shown in FIG. 5, the upper chuck 230 has a main body 260 (an example of a first member). The main body 260 is supported by a support member 270. The main body 260 is disposed facing the upper wafer W1 without contacting the upper wafer W1. The lower surface of the main body 260 is a facing surface facing the lower surface (non-bonding surface W1n) of the upper wafer W1. A through hole 266 is formed in the support member 270 and the main body 260, passing through the support member 270 and the main body 260 in the vertical direction. The position of the through hole 266 corresponds to the center of the upper wafer W1 held by suction on the upper chuck 230. A pressing pin 281 of a striker 280 is inserted into the through hole 266.

[0057] Striker 280 is disposed on the upper surface of support member 270, and includes a pressing pin 281, an actuator portion 282, and a linear motion mechanism 283. Pressing pin 281 is a columnar member extending along the vertical direction, and is supported by actuator portion 282. Striker 280 is an example of a pressing member.

[0058] The actuator unit 282 generates a constant pressure in a fixed direction (vertically downward in this case) by air supplied from, for example, an electropneumatic regulator (not shown). The actuator unit 282 can control the pressing load applied to the center of the upper wafer W1 by contacting the center of the upper wafer W1 by air supplied from the electropneumatic regulator. In addition, the tip of the actuator unit 282 can be raised and lowered vertically by passing through the through hole 266 by air from the electropneumatic regulator.

[0059] The actuator section 282 is supported by a linear motion mechanism 283. The linear motion mechanism 283 moves the actuator section 282 in the vertical direction by a drive section having a built-in motor, for example.

[0060] The striker 280 is configured as described above, and controls the movement of the actuator part 282 by the linear motion mechanism 283, and controls the pressing load of the pressing pin 281 on the upper wafer W1 by the actuator part 282. As a result, the striker 280 presses the center of the upper wafer W1 held by suction on the upper chuck 230 to bring it into contact with the lower wafer W2.

[0061] A plurality of pins 261 that come into contact with the upper surface (non-bonding surface W1n) of the upper wafer W1 are provided on the lower surface of the main body 260. The plurality of pins 261 have, for example, a diameter of 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 261 are evenly arranged at intervals of, for example, 2 mm.

[0062] The upper chuck 230 includes a plurality of suction portions for suctioning the upper wafer W1 in a portion of the region where the plurality of pins 261 are provided. Specifically, a lower surface of the main body 260 of the upper chuck 230 is provided with a plurality of outer suction portions 301 and inner suction portions 302 for suctioning the upper wafer W1 by vacuum drawing. The outer suction portions 301 and inner suction portions 302 each have an arc-shaped suction region in a plan view. The outer suction portions 301 and inner suction portions 302 have the same height as the pins 261.

[0063] 6, the multiple outer suction portions 301 are arranged side by side in the circumferential direction on the outer periphery of the main body portion 260. The multiple outer suction portions 301 are connected to a suction device (not shown) such as a vacuum pump, and suction the outer periphery of the upper wafer W1 by the suction force generated by the suction device.

[0064] The inner suction portion 302 is disposed along the circumferential direction, radially inward of the main body portion 260 from the multiple outer suction portions 301. The inner suction portion 302 is connected to a suction device (not shown), such as a vacuum pump, and sucks the region between the outer periphery and the center of the upper wafer W1 by the suction force generated by the suction device.

[0065] The above-mentioned pin 261, outer suction portion 301 and inner suction portion 302 are separate members from main body portion 260, and are formed of, for example, an insulating member.

[0066] Furthermore, the main body 260 is provided with a plurality of sensors 265. The sensors 265 detect the distance between the upper wafer W1 and the sensors 265. A specific configuration of the sensors 265 will be described later.

[0067] The lower chuck 231 has a main body 290 having a diameter equal to or larger than that of the lower wafer W2. Here, the lower chuck 231 having a diameter larger than that of the lower wafer W2 is shown. The upper surface of the main body 290 is an opposing surface that faces the lower surface (non-bonding surface W2n) of the lower wafer W2.

[0068] A plurality of pins 291 that come into contact with the lower surface (non-bonding surface W2n) of the lower wafer W2 are provided on the upper surface of the main body 290. The plurality of pins 291 have, for example, a diameter dimension of 0.1 mm to 1 mm and a height of several tens of μm to several hundreds of μm. The plurality of pins 291 are evenly arranged at intervals of, for example, 2 mm.

[0069] Further, a lower rib 292 is provided in an annular shape on the upper surface of the main body 290, outside the multiple pins 291. The lower rib 292 is formed in an annular shape, and supports the outer periphery of the lower wafer W2 over the entire circumference.

[0070] Furthermore, the main body 290 has a plurality of lower suction ports 293. The plurality of lower suction ports 293 are provided in a suction region surrounded by the lower ribs 292. The plurality of lower suction ports 293 are connected to a suction device (not shown) such as a vacuum pump via a suction pipe (not shown).

[0071] The lower chuck 231 reduces the pressure in the suction region surrounded by the lower ribs 292 through the lower suction ports 293. As a result, the lower wafer W2 placed in the suction region is sucked and held by the lower chuck 231.

[0072] Since the lower rib 292 supports the entire outer periphery of the lower surface of the lower wafer W2, the lower wafer W2 is appropriately sucked up to the outer periphery. This allows the entire surface of the lower wafer W2 to be suction-held. In addition, since the lower surface of the lower wafer W2 is supported by the multiple pins 291, the lower wafer W2 is easily peeled off from the lower chuck 231 when the suction of the lower wafer W2 is released.

[0073] It should be noted that the sensor 265 is not provided on the lower chuck 231. In other words, there is no sensor 265 on the opposite side of the main body part 260 across the upper wafer W1. That is, the distance measuring method according to this embodiment is different from, for example, a conventional non-contact thickness measurement method in which two sensors are arranged opposite to each other to sandwich the measurement object and measure the thickness of the measurement object.

[0074] In the bonding apparatus 41 according to the embodiment configured as described above, the tip of the pressing pin 281 presses the center of the upper wafer W1 held by suction on the upper chuck 230 to contact the lower wafer W2. As a result, a bonding wave is generated between the upper wafer W1 and the lower wafer W2, in which the bonding area expands from the center of the upper wafer W1 and the lower wafer W2 toward the outer periphery. Finally, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact with each other over their entire surfaces, forming the overlapped wafer T. At this time, the sensor 265 is used to measure the distance from the sensor 265 to the upper wafer W1 to measure the progress of the bonding wave. Accurate measurement of the progress of the bonding wave leads to improved bonding accuracy of the overlapped wafer T.

[0075] Here, a method of accurately measuring the progress of the bonding wave can be considered to increase the number of sensors 265. For example, by using a capacitance sensor that is smaller than an optical displacement meter or the like, the number of sensors 265 used to measure the distance to the upper wafer W1 can be increased. Note that, when the number of sensors 265 used to measure the distance to the upper wafer W1 is increased, the progress of the bonding wave can be accurately measured. In addition, by measuring the distance between the overlapped wafer T and the sensor 265 after bonding, the thickness distribution of the overlapped wafer T can also be accurately measured.

[0076] However, when a capacitance sensor is used as sensor 265, the object to be measured is usually a conductor and the capacitance sensor and the object to be measured are electrically conductive, but it was difficult to satisfy such requirements with conventional joining devices.

[0077] Therefore, the inventors of the present application found that if a conductive member is used as the main body 260 of the upper chuck 230 and the sensor 265 is grounded via the main body 260, it is possible to measure the distance between the sensor 265 and the upper wafer W1 even if there is no electrical continuity between the sensor 265 and the upper wafer W1. Fig. 7 is an enlarged schematic view of the main body 260 of the upper chuck 230, the sensors 265A to 265C, and the upper wafer W1 according to the embodiment. Fig. 8 is a graph showing changes in the measurement values ​​of the sensors 265A to 265C in Fig. 7.

[0078] 7, in this experiment, three capacitance sensors 265A to 265C are used to measure the distance from the main body part 260 to the upper wafer W1. The main body part 260 is disposed facing the upper wafer W1 in a non-contact manner. The main body part 260 is formed of a conductive member, and the sensors 265A to 265C are grounded via the main body part 260. Note that an insulating sheet may be provided between the main body part 260 and the wafer W3 to prevent electrical conduction between the upper wafer W1 and the main body part 260.

[0079] In Fig. 8, the vertical axis indicates the distance between the upper wafer W1 and the sensors 265A to 265C. Fig. 8 shows the experimental results when the distance between the upper wafer W1 and the sensors 265A to 265C is changed in the same manner, that is, when the main body part 260 is moved parallel to the upper wafer W1.

[0080] As shown in FIG. 8, as the distance between the upper wafer W1 and the sensors 265A to 265C increases, the measurement values ​​of the sensors 265A to 265C increase.

[0081] Thus, from the experimental results shown in FIG. 8, it can be seen that if a conductive material is used as the main body portion 260 of the upper chuck 230 and the sensor 265 is grounded via the main body portion 260, it is possible to measure the distance between the sensor 265 and the upper wafer W1.

[0082] Therefore, the sensor 265 in the bonding device 41 according to the embodiment is grounded via the main body 260. The main body 260 is formed of a conductive member. The conductive member may be, but is not limited to, a metal material or a ceramic having conductivity. As an example, the main body 260 may be formed of aluminum. The main body 260 may be subjected to a surface treatment such as an antistatic coating.

[0083] The multiple sensors 265 provided on the main body 260 are capacitive sensors. As shown in FIG. 6, the multiple sensors 265 are provided on the lower surface of the main body 260 along the radial direction. Specifically, the bonding wave expands faster in the 45-degree direction than in the 90-degree direction. The 90-degree direction is a direction with a period of 90 degrees (0 degrees, 90 degrees, 180 degrees, 270 degrees) based on a direction from the center of the upper wafer W1 toward the [0-11] crystal direction parallel to the surface of the upper wafer W1. The 45-degree direction is a direction with a period of 90 degrees (45 degrees, 135 degrees, 225 degrees, 315 degrees) based on a direction from the center of the upper wafer W1 toward the

[0010] crystal direction parallel to the surface of the upper wafer W1. The multiple sensors 265 are arranged side by side along the 90-degree direction and the 45-degree direction.

[0084] The area of ​​the surface of the main body part 260 facing the upper wafer W1 may be the same as or larger than the area of ​​the surface of the upper wafer W1 facing the main body part 260. The main body part 260 and the upper wafer W1 are not in contact with each other, but the sensor 265 can detect a sufficient capacitance for distance measurement because the facing area between the conductive main body part 260 and the upper wafer W1 is large. Therefore, the distance to the upper wafer W1 can be measured without establishing electrical continuity between the sensor 265 and the upper wafer W1, which is the object to be measured.

[0085] The lower chuck 231 may be made of an insulating (non-conductive) material. If the lower chuck 231 were made of a conductive material, electrical continuity would be established between the sensor 265 and the lower chuck 231, which could cause the capacitance detected by the sensor 265 to become unstable, resulting in an unstable measurement value. By forming the lower chuck 231 from an insulating material, such a possibility can be reduced. Examples of insulating materials that can be used include, but are not limited to, alumina ceramics and silicon nitride.

[0086] <Specific operation of the joining system> Next, a specific operation of the bonding system 1 according to the embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing a procedure of processing executed by the bonding system 1 according to the embodiment. Various processing shown in Fig. 9 is executed based on the control of the control device 70.

[0087] First, the cassette C1 accommodating a plurality of upper wafers W1, the cassette C2 accommodating a plurality of lower wafers W2, and an empty cassette C3 are placed on a predetermined placement plate 11 of the load / unload station 2. After that, the upper wafer W1 in the cassette C1 is removed by the transfer device 22 and transferred to a transition device arranged in the third processing block G3.

[0088] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface modification device 30 in the first processing block G1. In the surface modification device 30, oxygen gas, which is a processing gas, is excited to be turned into plasma and ionized in a predetermined reduced pressure atmosphere. The oxygen ions are irradiated onto the bonding surface of the upper wafer W1, and the bonding surface is subjected to plasma processing. As a result, the bonding surface of the upper wafer W1 is modified (step S101).

[0089] Next, the upper wafer W1 is transferred by the transfer device 61 to the surface hydrophilization device 40 in the first processing block G1. In the surface hydrophilization device 40, pure water is supplied onto the upper wafer W1 while rotating the upper wafer W1 held by the spin chuck. This makes the bonding surface of the upper wafer W1 hydrophilic. In addition, the bonding surface of the upper wafer W1 is cleaned by the pure water (step S102).

[0090] Next, the upper wafer W1 is transferred to the bonding device 41 in the second processing block G2 by the transfer device 61. The upper wafer W1 carried into the bonding device 41 is transferred to the position adjustment mechanism 210 via the transition 200, and its horizontal orientation is adjusted by the position adjustment mechanism 210 (step S103).

[0091] Thereafter, the upper wafer W1 is transferred from the position adjustment mechanism 210 to the inversion mechanism 220, and the upper wafer W1 is inverted upside down by the inversion mechanism 220 (step S104). Specifically, the bonding surface W1j of the upper wafer W1 faces downward. Next, the upper wafer W1 is transferred from the inversion mechanism 220 to the upper chuck 230, and the upper wafer W1 is adsorbed and held by the upper chuck 230 (step S105).

[0092] The processing of the lower wafer W2 overlaps with the processing of steps S101 to S105 for the upper wafer W1. First, the transfer device 22 removes the lower wafer W2 from the cassette C2 and transfers it to a transition device disposed in the third processing block G3.

[0093] Next, the lower wafer W2 is transferred by the transfer device 61 to the surface modification device 30, where the bonding surface W2j of the lower wafer W2 is modified (step S106). Thereafter, the lower wafer W2 is transferred by the transfer device 61 to the surface hydrophilization device 40, where the bonding surface W2j of the lower wafer W2 is hydrophilized and the bonding surface is cleaned (step S107).

[0094] Thereafter, the lower wafer W2 is transferred to the bonding apparatus 41 by the transfer device 61. The lower wafer W2 carried into the bonding apparatus 41 is transferred to the position adjustment mechanism 210 via the transition 200. Then, the horizontal orientation of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S108).

[0095] Thereafter, the lower wafer W2 is transferred to the lower chuck 231 and is attracted and held by the lower chuck 231 with the notch portion facing a predetermined direction (step S109).

[0096] Next, the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted in the horizontal direction (step S110). Then, the lower wafer W2 is raised by using the first moving part 250, and the upper wafer W1 and the lower wafer W2 are bonded together (step S111). Specifically, the lower wafer W2 is first raised, and then the center of the upper wafer W1 is pressed downward from above by using the pressing pin 281 of the striker 280 to contact the center of the lower wafer W2, thereby starting bonding between the central parts. Then, a bonding wave is generated between the upper wafer W1 and the lower wafer W2, in which the bonding area expands from the center of the upper wafer W1 and the lower wafer W2 toward the outer periphery. Then, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 come into contact with each other over their entire surfaces, and the upper wafer W1 and the lower wafer W2 are bonded together.

[0097] In step S111, the multiple sensors 265 are used to detect the distance to the upper wafer W1, measure the progress of the bonding wave, and inspect the bonding state of the upper wafer W1 and the lower wafer W2. As described above, the multiple sensors 265 are arranged in a line along the radial direction of the upper wafer W1. The bonding device 41 detects the distance between the sensor 265 and the upper wafer W1 at multiple points along the radial direction of the upper wafer W1, and can observe the boundary position between the bonded area of ​​the upper wafer W1 and the lower wafer W2 and the unbonded area located outside the bonded area based on the detected distance.

[0098] As described above, in the bonding apparatus 41 according to the embodiment, the main body 260 of the upper chuck 230 is formed of a conductive member, and the sensor 265 is grounded via the main body 260. With this configuration, it is possible to measure the distance to the upper wafer W1, which is the measurement object, without establishing electrical continuity between the upper wafer W1 and the sensor 265. In addition, because the upper wafer W1 is a semiconductor, it is possible to measure the distance using the sensor 265 even if the measurement object is not a conductor.

[0099] In the embodiment, the upper wafer W1 is used as the measurement object, but the measurement object is not limited to this. For example, the measurement object may be a conductor. In this case, the distance to the measurement object can be measured without establishing electrical continuity between the measurement object and the sensor 265.

[0100] The present disclosure may also be configured as follows. (1) A first member disposed opposite to a measurement object that is a conductor or a semiconductor without contacting the measurement object; a capacitance sensor provided on the first member for detecting a distance between the first member and the object to be measured; Equipped with A distance measuring device, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member. (2) The distance measuring device according to (1), comprising a plurality of the capacitance sensors. (3) A distance measuring device as described in (1) or (2), wherein an area of ​​the surface of the first member facing the object to be measured is the same as or larger than an area of ​​the surface of the object to be measured facing the first member. (4) A process for measuring a distance to a measurement object, which is a conductor or semiconductor, using a first member made of a conductive material and disposed opposite the measurement object without contacting the first member, and a capacitance sensor provided on the first member for detecting the distance to the measurement object, the capacitance sensor being grounded via the first member. A distance measurement method including: (5) a first holding portion that suction-holds the first substrate from above; a second holding section that is disposed below the first holding section and that suction-holds a second substrate from below; a pressing member provided in the first holding portion and configured to press a central portion of the first substrate; Equipped with The first holding portion is A first member disposed opposite the first substrate in a non-contact manner; a capacitance sensor provided on the first member for detecting a distance between the first member and the first substrate; Equipped with A joining device, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member. (6) The bonding device described in (5), wherein an area of ​​the surface of the first component facing the first substrate is the same as or larger than an area of ​​the surface of the first substrate facing the first component. (7) The second holding portion is The joining device according to (5) or (6), which is formed of an insulating material. (8) A plurality of the capacitance sensors are arranged along a radial direction of the first member, a control unit that detects a distance to the first substrate using the plurality of capacitance sensors, thereby observing a boundary position between a bonded region where the first substrate and the second substrate are bonded and an unbonded region located outside the bonded region. The bonding device according to any one of (5) to (7), comprising: (9) a step of adsorbing and holding the first substrate from above using a first holding unit that adsorbs and holds the first substrate from above, the first holding unit including a first member that is arranged to face the first substrate without contacting the first substrate, and a capacitance sensor that is provided on the first member and detects a distance between the first substrate and the first substrate; a step of suction-holding the second substrate from below using a second holding unit that is disposed below the first substrate and that suction-holds the second substrate from below; pressing a central portion of the first substrate, which is attracted and held by the first holding portion, using a pressing member provided on the first holding portion and configured to press the central portion of the first substrate; detecting a distance between the first substrate and the capacitance sensor; Including, A joining method, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member. (10) The first holding portion includes a plurality of the capacitance sensors arranged along a radial direction of the first member, observing a boundary position between a bonded region where the first substrate and the second substrate are bonded and an unbonded region located outside the bonded region, based on the distance detected in the detecting step; The bonding method according to (9), comprising:

[0101] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. Indeed, the above-described embodiments may be embodied in various forms. In addition, the above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims. [Explanation of symbols]

[0102] 1 Joining System 30 Surface modification equipment 40 Surface hydrophilization device 41 Bonding equipment 70 Control device 71 Control Unit 230 Upper chuck 231 Lower chuck 235 Upper Imaging Section 236 Lower imaging section 250 First Mobile Section 253 Second Mobile Division 255 Placement table 256 Position adjustment section 260 Main body 265 Sensors 266 Through hole 270 Support member 280 Striker 281 Pressing pin

Claims

1. A first member disposed opposite to a measurement object that is a conductor or a semiconductor in a non-contact manner; a capacitance sensor provided on the first member for detecting a distance between the first member and the object to be measured; Equipped with A distance measuring device, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member.

2. The distance measuring device according to claim 1 , comprising a plurality of the capacitance sensors.

3. 2. The distance measurement device according to claim 1, wherein an area of ​​the surface of the first member facing the object to be measured is the same as or larger than an area of ​​the surface of the object to be measured facing the first member.

4. A process of measuring a distance to a measurement object, which is a conductor or a semiconductor, by using a first member made of a conductive material and a capacitance sensor provided on the first member for detecting the distance to the measurement object, the capacitance sensor being grounded via the first member. A distance measurement method including:

5. a first holding portion that suction-holds the first substrate from above; a second holding portion that is disposed below the first holding portion and that suction-holds a second substrate from below; a pressing member provided in the first holding portion and configured to press a central portion of the first substrate; Equipped with The first holding portion is a first member disposed opposite the first substrate in a non-contact manner; a capacitance sensor provided on the first member for detecting a distance between the first member and the first substrate; Equipped with A joining device, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member.

6. The bonding apparatus according to claim 5 , wherein an area of ​​the surface of the first member facing the first substrate is the same as or larger than an area of ​​the surface of the first substrate facing the first member.

7. The second holding portion is 6. The joining device according to claim 5, which is made of an insulating material.

8. A plurality of the capacitance sensors are arranged along a radial direction of the first member, a control unit that detects a distance to the first substrate using the plurality of capacitance sensors, thereby observing a boundary position between a bonded region where the first substrate and the second substrate are bonded and an unbonded region located outside the bonded region. The joining device according to claim 5 .

9. a step of adsorbing and holding the first substrate from above using a first holding unit that adsorbs and holds the first substrate from above, the first holding unit including a first member that is arranged to face the first substrate without contacting the first substrate, and a capacitance sensor that is provided on the first member and detects a distance between the first substrate and the first substrate; a step of suction-holding the second substrate from below using a second holding unit that is disposed below the first substrate and suction-holds the second substrate from below; pressing a central portion of the first substrate, which is attracted and held by the first holding portion, using a pressing member provided on the first holding portion and configured to press the central portion of the first substrate; detecting a distance between the first substrate and the capacitance sensor; Including, A joining method, wherein the first member is formed of a conductive member, and the capacitance sensor is grounded via the first member.

10. The first holding portion includes a plurality of the capacitance sensors arranged along a radial direction of the first member, A step of observing a boundary position between a bonded region where the first substrate and the second substrate are bonded and an unbonded region located outside the bonded region, based on the distance detected in the detecting step. The bonding method according to claim 9 , comprising:

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