Distance measurement device, distance measurement method, bonding device, and bonding method

Abstract

The present disclosure provides a distance measurement device, a distance measurement method, a bonding device, and a bonding method, which can perform distance measurement using an electrostatic capacitance sensor even if there is no conduction between the electrostatic capacitance sensor and an object to be measured. This distance measurement device is provided with a first member and a capacitance sensor. The first member is disposed so as to face an object to be measured, which is a conductor or a semiconductor, in a non-contact manner. The capacitance sensor is provided on the first member and detects the distance from the object to be measured. The first member is formed of a conductive member, and the capacitance sensor is grounded via the first member.

Description

Technical Field

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

[0002] Conventionally, there is known a bonding apparatus for bonding substrates such as semiconductor wafers to each other (see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-147944 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The present disclosure provides a technology that enables distance measurement using an electrostatic capacitance sensor even when there is no conduction between the electrostatic capacitance sensor and a measurement object.

[0008] Solutions for solving problems

[0009] A distance measuring device according to one embodiment of the present disclosure includes a first member and an electrostatic capacitance sensor. The first member is arranged in a non-contact manner facing a measuring object that is a conductor or a semiconductor. The electrostatic capacitance sensor is arranged on the first member to detect the distance between the first member and the measuring object. The first member is formed by a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

[0010] Effects of the Invention

[0011] According to the present disclosure, even when there is no conduction between the capacitance sensor and the object to be measured, distance measurement can be performed using the capacitance sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic plan view showing the structure of the joining system according to the embodiment.

[0013] Figure 2 1 is a schematic side view of an upper wafer and a lower wafer according to an embodiment.

[0014] Figure 3 It is a schematic plan view showing the structure of the bonding device according to the embodiment.

[0015] Figure 4 It is a schematic side view showing the structure of the bonding device according to the embodiment.

[0016] Figure 5Schematic diagram showing an upper holding plate and a lower holding plate according to the embodiment.

[0017] Figure 6 This is a schematic diagram of the upper retaining plate as viewed from below the upper retaining plate.

[0018] Figure 7 It is an enlarged schematic diagram of a main body of an upper holding plate, a sensor, and an upper wafer according to an embodiment.

[0019] Figure 8 It is shown Figure 7 A graph showing the changes in the measured values ​​of the sensors.

[0020] Fig. 9 This is a flowchart showing the procedure of processing executed by the joining system according to the embodiment. DETAILED DESCRIPTION

[0021] Below, the distance measuring device, distance measuring method, joining device and joining method for implementing the present disclosure are described in detail with reference to the accompanying drawings (hereinafter referred to as "implementation methods"). In addition, the present disclosure is not limited by the implementation methods. In addition, the various implementation methods can be appropriately combined within the scope that does not cause contradictions in the processing contents. In addition, in the following embodiments, the same reference numerals are marked on the same parts, and repeated descriptions are omitted.

[0022] In the embodiments described below, expressions such as "fixed", "orthogonal", "perpendicular" or "parallel" are sometimes used, but these expressions do not need to be strictly "fixed", "orthogonal", "perpendicular" or "parallel". That is, the above expressions allow for deviations in manufacturing accuracy, setting accuracy, etc.

[0023] In addition, in the drawings referred to below, an orthogonal coordinate system is sometimes shown in which mutually orthogonal X-axis direction, Y-axis direction and Z-axis direction are defined and the positive direction of the Z-axis is set as the vertical upward direction to make the description easier to understand. In addition, the rotation direction with the vertical axis as the rotation center is sometimes referred to as the θ direction.

[0024] When substrates are bonded to each other by intermolecular forces, when the center of one substrate is pressed to make it contact with another substrate, a bonding wave is generated in which the bonding area expands from the center of the substrate toward the periphery. In the bonding device, a process of measuring the progress of the bonding wave is sometimes performed. For example, a process of measuring the progress of the bonding wave is performed by using a sensor provided on a holding portion that adsorbs and holds the substrate from above to measure the distance from the holding portion to the substrate (measurement object). By accurately measuring the progress of the bonding wave, the bonding accuracy of the substrates will be improved.

[0025] Here, as a method for accurately measuring the progress of the bonding wave, a method of increasing the number of sensors used in measuring the distance between the holding portion and the substrate is considered. For example, by using a small electrostatic capacitance sensor compared to an optical displacement meter, the number of sensors used in measuring the distance between the substrate and the holding portion can be increased.

[0026] However, when using an electrostatic capacitance sensor, the object to be measured is usually a conductor, and the electrostatic capacitance sensor and the object to be measured are electrically connected, but this requirement is difficult to meet in a bonding device that bonds substrates to each other. Therefore, a technology that can measure the distance using an electrostatic capacitance sensor even when there is no electrical connection between the electrostatic capacitance sensor and the object to be measured is desired.

[0027] In addition, the above technology is not limited to the bonding device, and is also expected to be used in other devices. Below, an embodiment of the distance measuring device and distance measuring method disclosed in the present invention is described when applied to a bonding device, but the distance measuring device and distance measuring method disclosed in the present invention can also be applied to devices other than bonding devices.

[0028] <Structure of the joint system>

[0029] First, refer to Figure 1 , Figure 2 The structure of the joining system 1 according to the embodiment will be described. Figure 1 It is a schematic plan view showing the structure of the joining system 1 according to the embodiment. Figure 2 1 is a schematic side view of the upper wafer W1 and the lower wafer W2 according to the embodiment.

[0030] Figure 1 The bonding system 1 shown forms a superposed wafer T by bonding a first substrate W1 and a second substrate W2 .

[0031] 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 substantially the same diameter.

[0032] Hereinafter, the first substrate W1 is described as "upper wafer W1", and the second substrate W2 is described as "lower wafer W2". That is, the upper wafer W1 is an example of the first substrate, and the lower wafer W2 is an example of the second substrate. In addition, when the upper wafer W1 and the lower wafer W2 are collectively referred to, they are sometimes described as "wafer W".

[0033] In addition, the following Figure 2As shown, the plate surface of the upper wafer W1 on the side to be bonded to the lower wafer W2 is recorded as a "bonding surface W1j", and the plate surface on the side opposite to the bonding surface W1j is recorded as a "non-bonding surface W1n". In addition, the plate surface of the lower wafer W2 on the side to be bonded to the upper wafer W1 is recorded as a "bonding surface W2j", and the plate surface on the side opposite to the bonding surface W2j is recorded as a "non-bonding surface W2n".

[0034] like Figure 1 As shown, the bonding system 1 includes a loading and unloading station 2 and a processing station 3. The loading and unloading station 2 and the processing station 3 are arranged in the order of the loading and unloading station 2 and the processing station 3 along the positive direction of the X axis. In addition, the loading and unloading station 2 and the processing station 3 are integrally connected.

[0035] The loading and unloading station 2 includes a loading platform 10 and a conveying area 20. The loading platform 10 includes a plurality of loading plates 11. Boxes C1, C2, and C3 for accommodating a plurality of (e.g., 25) substrates in a horizontal state are placed on each loading plate 11. For example, box C1 is a box for accommodating an upper wafer W1, box C2 is a box for accommodating a lower wafer W2, and box C3 is a box for accommodating an overlapped wafer T.

[0036] The conveyance area 20 is disposed adjacent to the X-axis positive direction side of the mounting table 10. In the conveyance area 20, a conveyance path 21 extending in the Y-axis direction and a conveyance device 22 movable along the conveyance path 21 are provided.

[0037] The transfer device 22 can move not only in the Y-axis direction but also in the X-axis direction and can rotate about 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 the third processing block G3 of the processing station 3 described later.

[0038] The number of cassettes C1 to C3 placed on the placement plate 11 is not limited to the number shown in the figure. In addition, on the placement plate 11, in addition to the cassettes C1, C2, and C3, a cassette for collecting defective substrates may be placed.

[0039] The processing station 3 is provided with a plurality of processing blocks equipped with various devices, for example, three processing blocks G1, G2, and G3. Figure 1 A first processing block G1 is provided on the negative side of the Y axis of the processing station 3. Figure 1 A second processing block G2 is provided on the positive Y-axis side of the processing station 3. Figure 1 A third processing block G3 is provided on the negative X-axis direction side.

[0040] The first processing block G1 is provided with a surface modification device 30 for modifying the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2. The surface modification device 30 modifies the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 by cutting the bonds of SiO2 in the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 into single-bonded SiO, thereby modifying the bonding surfaces W1j and W2j so that they can be easily hydrophilized later.

[0041] In addition, the first processing block G1 is provided with a surface hydrophilizing device 40. The surface hydrophilizing device 40 hydrophilizes the bonding surfaces W1j and W2j of the upper wafer W1 and the lower wafer W2 using, for example, pure water, and cleans the bonding surfaces W1j and W2j.

[0042] In the surface hydrophilization device 40, for example, pure water is supplied onto the upper wafer W1 or the lower wafer W2 held on a rotating holding plate (holding plate: chuck) while rotating the upper wafer W1 or the lower wafer W2. Thus, the pure water supplied onto the upper wafer W1 or the lower wafer W2 spreads on the bonding surfaces W1j and W2j of the upper wafer W1 or the lower wafer W2, and the bonding surfaces W1j and W2j are hydrophilized.

[0043] Here, an example is shown in which the surface modification device 30 and the surface hydrophilization device 40 are arranged side by side in a horizontal manner, but the surface hydrophilization device 40 may be stacked above or below the surface modification device 30 .

[0044] In addition, a bonding device 41 is disposed in the second processing block G2. The bonding device 41 bonds the hydrophilized upper wafer W1 and the lower wafer W2 by intermolecular force. The bonding device 41 will be described in detail later.

[0045] The third processing block G3 is provided with a transfer (TRS) device (not shown) for the upper wafer W1 , the lower wafer W2 , and the overlapped wafer T.

[0046] In addition, if Figure 1 As shown, a conveying area 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 conveying device 61 is disposed in the conveying area 60. The conveying device 61 has, for example, a conveying arm that is movable in the vertical direction, the horizontal direction, and around the vertical axis.

[0047] The transfer device 61 moves in the transfer area 60 to transfer the upper wafer W1 , the lower wafer W2 , and the overlapped wafer T to predetermined devices in the first processing block G1 , the second processing block G2 , and the third processing block G3 adjacent to the transfer area 60 .

[0048] In addition, the joining system 1 includes a control device 70. The control device 70 controls the operation of the joining 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 CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output port, and various circuits. The CPU of the microcomputer realizes the control described later by reading and executing the program stored in the ROM. In addition, 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.

[0049] In addition, the program may be recorded in a computer-readable recording medium and installed from the recording medium to the storage unit 72 of the control device 70. Examples of computer-readable recording media include a hard disk (HD), a floppy disk (FD), a compact disk (CD), a magneto-optical disk (MO), and a memory card.

[0050] <Structure of bonding device>

[0051] Next, refer to Figure 3 and Figure 4 The structure of the bonding device 41 will be described. Figure 3 is a schematic plan view showing the structure of a bonding device 41 according to the embodiment. Figure 4 It is a schematic side view showing the structure of a joining device 41 according to the embodiment.

[0052] like Figure 3 As shown, the bonding apparatus 41 has a sealed processing container 190. A loading and unloading port 191 for the upper wafer W1, the lower wafer W2 and the overlapped wafer T is formed on the side of the processing container 190 near the transfer area 60, and an opening and closing gate 192 is provided at the loading and unloading port 191.

[0053] The interior of the processing container 190 is divided into a transfer area T1 and a processing area T2 by an inner wall 193. The above-mentioned loading and unloading port 191 is formed on the side of the processing container 190 in the transfer area T1. In addition, a loading and unloading port 194 for the upper wafer W1, the lower wafer W2 and the overlapped wafer T is also formed on the inner wall 193.

[0054] In the transfer region T1 , for example, the conveyor 200 , the substrate transfer mechanism 201 , the reversing mechanism 220 , and the position adjustment mechanism 210 are arranged in order from the loading / unloading port 191 side.

[0055] The transfer unit 200 is used to temporarily place the upper wafer W1 , the lower wafer W2 , and the overlapped wafer T. The transfer unit 200 is formed in two stages, for example, and can place any two of the upper wafer W1 , the lower wafer W2 , and the overlapped wafer T at the same time.

[0056] The substrate transport mechanism 201 has a transport arm that is movable in the vertical direction (Z-axis direction), the horizontal direction (Y-axis direction, X-axis direction) and the direction around the vertical axis (θ direction). The substrate transport mechanism 201 can transport the upper wafer W1, the lower wafer W2 and the overlapped wafer T within the transport area T1 or between the transport area T1 and the processing area T2.

[0057] 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, which has a holding portion (not shown) for holding and rotating the upper wafer W1 and the lower wafer W2; and a detection portion 212, which detects the position of the cutout portion of the upper wafer W1 and the lower wafer W2. The position adjustment mechanism 210 adjusts the position of the cutout portion by rotating the upper wafer W1 and the lower wafer W2 held on the base 211 while using the detection portion 212 to detect the position of the cutout portion of the upper wafer W1 and the lower wafer W2. Thus, the horizontal orientation of the upper wafer W1 and the lower wafer W2 is adjusted.

[0058] The flip mechanism 220 flips the front and back of the upper wafer W1. Specifically, the flip mechanism 220 has a holding arm 221 for holding the upper wafer W1. The holding arm 221 extends in the horizontal direction (X-axis direction). In addition, holding members 222 for holding the upper wafer W1 are provided at, for example, four locations of the holding arm 221.

[0059] The holding arm 221 is supported by a driving unit 223 having a motor or the like, for example. The holding arm 221 is freely rotatable around a horizontal axis by the driving unit 223. In addition, the holding arm 221 is freely rotatable around the driving unit 223 and is freely movable in the horizontal direction (X-axis direction). Another driving unit (not shown) having a motor or the like is provided below the driving unit 223, for example. The driving unit 223 can move in the vertical direction along a support column 224 extending in the vertical direction through the other driving unit.

[0060] As described above, the upper wafer W1 held by the holding member 222 can be rotated around the horizontal axis by the driving unit 223 and can move in the vertical direction and the horizontal direction. In addition, the upper wafer W1 held by the holding member 222 can be rotated around the driving unit 223 and move between the position adjustment mechanism 210 and the upper holding disk 230 described later.

[0061] An upper holding disk 230 for adsorbing and holding the upper surface (non-bonding surface W1n) of the upper wafer W1 from above, and a lower holding disk 231 for adsorbing and holding the lower surface (non-bonding surface W2n) of the lower wafer W2 from below are provided in the processing area T2. The lower holding disk 231 is arranged at a position lower than the upper holding disk 230, and the lower holding disk 231 is configured to be arranged opposite to the upper holding disk 230. The upper holding disk 230 and the lower holding disk 231 are, for example, vacuum holding disks. The upper holding disk 230 is an example of a first holding portion, and the lower holding disk 231 is an example of a second holding portion. The specific structures of the upper holding disk 230 and the lower holding disk 231 will be described later.

[0062] like Figure 4 As shown, the upper holding plate 230 is supported by a supporting member 270 disposed above the upper holding plate 230. The supporting member 270 is fixed to the top surface of the processing container 190 by means of a plurality of supporting columns 271, for example.

[0063] An upper imaging unit 235 for imaging the upper surface (joining surface W2j) of the lower wafer W2 held on the lower holding plate 231 is provided on the side of the upper holding plate 230. For example, a CCD camera is used as the upper imaging unit 235.

[0064] The lower holding plate 231 is supported by a first moving portion 250 provided below the lower holding plate 231. The first moving portion 250 moves the lower holding plate 231 in the horizontal direction (X-axis direction) as described later. In addition, the first moving portion 250 is configured to allow the lower holding plate 231 to move freely in the vertical direction and to be able to rotate the lower holding plate 231 around the vertical axis.

[0065] The first moving unit 250 is provided with a lower imaging unit 236 for imaging the lower surface (joining surface W1j) of the upper wafer W1 held on the upper holding plate 230. For example, a CCD camera is used for the lower imaging unit 236. The lower imaging unit 236 is an example of an imaging unit.

[0066] The first moving part 250 is attached to a pair of guide rails 252, 252. The pair of guide 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 guide rails 252.

[0067] A pair of guide rails 252, 252 is disposed on the second moving part 253. The second moving part 253 is mounted on a pair of guide rails 254, 254. The pair of guide rails 254, 254 is disposed on the lower surface side of the second moving part 253 and extends 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 guide rails 254. In addition, the pair of guide rails 254, 254 is disposed on a mounting table 255 disposed on the bottom surface of the processing container 190.

[0068] The position adjustment unit 256 is composed of the first moving unit 250 and the second moving unit 253. The position adjustment unit 256 adjusts the position in the horizontal direction between the upper wafer W1 held on the upper holding disk 230 and the lower wafer W2 held on the lower holding disk 231 by moving the lower holding disk 231 in the X-axis direction, the Y-axis direction, and the θ direction. In addition, the position adjustment unit 256 adjusts the position in the vertical direction between the upper wafer W1 held on the upper holding disk 230 and the lower wafer W2 held on the lower holding disk 231 by moving the lower holding disk 231 in the Z-axis direction.

[0069] In addition, here, the lower holding plate 231 is set to move in the X-axis direction, the Y-axis direction, and the θ direction, but the position adjustment unit 256 may also move the lower holding plate 231 in the X-axis direction and the Y-axis direction, and move the upper holding plate 230 in the θ direction. In addition, here, the lower holding plate 231 is set to move in the Z-axis direction, but the position adjustment unit 256 may also move the upper holding plate 230 in the Z-axis direction, for example.

[0070] Next, refer to Figure 5 The structures of the upper holding plate 230 and the lower holding plate 231 will be described. Figure 5 Schematic diagram showing the upper holding plate 230 and the lower holding plate 231 according to the embodiment. Figure 6 This is a schematic diagram of the upper holding plate 230 as viewed from below.

[0071] like Figure 5 As shown, the upper holding disk 230 has a main body 260 (an example of a first member). The main body 260 is supported by a supporting member 270. The main body 260 is arranged to face the upper wafer W1 in a non-contact manner. The lower surface of the main body 260 is an opposing surface facing the lower surface (non-bonding surface W1n) of the upper wafer W1. A through hole 266 is formed in the supporting member 270 and the main body 260, which penetrates the supporting 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 adsorbed and held on the upper holding disk 230. A pressing pin 281 of a striker (Japanese: ストライカー) 280 is inserted into the through hole 266.

[0072] The striker 280 is disposed on the upper surface of the support member 270, and includes a pressing pin 281, an actuator 282, and a linear motion mechanism 283. The pressing pin 281 is a cylindrical member extending in the vertical direction, and is supported by the actuator 282. The striker 280 is an example of a pressing member.

[0073] The actuator part 282 generates a fixed pressure in a fixed direction (here, vertically downward) by using air supplied from an electric pneumatic regulator (not shown), for example. The actuator part 282 can control the pressing load applied to the center of the upper wafer W1 by contacting the center of the upper wafer W1 with the air supplied from the electric pneumatic regulator. In addition, the front end of the actuator part 282 is inserted into the through hole 266 by the air from the electric pneumatic regulator and can be freely raised and lowered in the vertical direction.

[0074] The actuator part 282 is supported by the linear motion mechanism 283. The linear motion mechanism 283 moves the actuator part 282 in the vertical direction by a driving part including, for example, a motor.

[0075] The striker 280 is configured as described above, and the movement of the actuator 282 is controlled by the direct-acting mechanism 283, and the pressing load of the pressing pin 281 on the upper wafer W1 is controlled by the actuator 282. Thus, the striker 280 presses the center of the upper wafer W1 held by suction on the upper holding plate 230 to make it contact with the lower wafer W2.

[0076] A plurality of pins 261 for contacting the upper surface (non-joint surface W1n) of the upper wafer W1 are provided on the lower surface of the main body 260. The diameter of the plurality of pins 261 is, for example, 0.1 mm to 1 mm, and the height is, for example, several tens of μm to several hundreds of μm. The plurality of pins 261 are evenly arranged at intervals of, for example, 2 mm.

[0077] The upper holding plate 230 has a plurality of suction parts for sucking the upper wafer W1 in a part of the area where the plurality of pins 261 are provided. Specifically, a plurality of outer suction parts 301 and inner suction parts 302 are provided on the lower surface of the main body 260 of the upper holding plate 230 to suck the upper wafer W1 by vacuuming the upper wafer W1. The plurality of outer suction parts 301 and inner suction parts 302 have a suction area in the shape of an arc when viewed from above. The plurality of outer suction parts 301 and inner suction parts 302 have the same height as the pins 261.

[0078] like Figure 6 As shown, the plurality of outer suction parts 301 are arranged in a circumferential direction on the outer periphery of the main body 260. The plurality of outer suction parts 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.

[0079] The inner suction part 302 is arranged radially inward of the main body 260 relative to the plurality of outer suction parts 301 along the circumferential direction. The inner suction part 302 is connected to a suction device (not shown) such as a vacuum pump, and suctions the area between the outer periphery and the center of the upper wafer W1 using suction force generated by the suction device.

[0080] The pin 261 , the outer suction portion 301 , and the inner suction portion 302 are components that are separate from the main body 260 , and are formed of, for example, insulating components.

[0081] In addition, a plurality of sensors 265 are provided in the main body 260. The sensors 265 detect the distance between the upper wafer W1 and the sensors 265. The specific structure of the sensors 265 will be described later.

[0082] The lower holding plate 231 has a main body 290 having a diameter that is the same as or larger than the diameter of the lower wafer W2. Here, the lower holding plate 231 having a diameter larger than the diameter of the lower wafer W2 is shown. The upper surface of the main body 290 is a facing surface facing the lower surface (non-bonding surface W2n) of the lower wafer W2.

[0083] A plurality of pins 291 for contacting the lower surface (non-joint surface W2n) of the lower wafer W2 are provided on the upper surface of the main body 290. The diameter of the plurality of pins 291 is, for example, 0.1 mm to 1 mm, and the height is, for example, several tens of μm to several hundreds of μm. The plurality of pins 291 are evenly arranged at intervals of, for example, 2 mm.

[0084] In addition, a lower rib 292 is provided annularly on the upper surface of the main body 290 outside the plurality of pins 291. The lower rib 292 is formed annularly and supports the outer periphery of the lower wafer W2 over the entire periphery of the lower wafer W2.

[0085] The main body 290 has a plurality of lower suction ports 293. The plurality of lower suction ports 293 are provided in a plurality in the adsorption region surrounded by the lower rib 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).

[0086] The lower holding disk 231 reduces the pressure in the suction region by suctioning the suction region surrounded by the lower ribs 292 from the plurality of lower suction ports 293 , so that the lower wafer W2 placed in the suction region is suction-held by the lower holding disk 231 .

[0087] Since the lower ribs 292 support the outer periphery of the lower surface of the lower wafer W2 over the entire periphery of the lower surface of the lower wafer W2, the lower wafer W2 is appropriately attracted to the outer periphery. Thus, the entire surface of the lower wafer W2 can be adsorbed and held. In addition, since the lower surface of the lower wafer W2 is supported by a plurality of pins 291, when the attraction of the lower wafer W2 is released, the lower wafer W2 is easily peeled off from the lower holding plate 231.

[0088] In addition, the sensor 265 is not provided on the lower holding plate 231. In other words, the sensor 265 does not exist at a position opposite to the main body 260 across the upper wafer W1. That is, the distance measurement method involved in this embodiment is different from, for example, the conventional non-contact thickness measurement method in which two sensors are arranged facing each other across the measurement object to measure the thickness of the measurement object.

[0089] The bonding device 41 involved in the embodiment constructed as described above presses the central part of the upper wafer W1 held by the upper holding plate 230 at the front end of the pressing pin 281 to make it contact with 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. Moreover, the bonding surface W1j of the upper wafer W1 and the bonding surface W2j of the lower wafer W2 eventually abut with the entire surface to form an overlapping wafer T. At this time, a process of measuring the progress of the bonding wave by measuring the distance from the sensor 265 to the upper wafer W1 using the sensor 265 is performed. By accurately measuring the progress of the bonding wave, the bonding accuracy of the overlapping wafer T will be improved.

[0090] Here, as a method for accurately measuring the progress of the bonding wave, a method of increasing the number of sensors 265 is considered. For example, by using a small electrostatic capacitance sensor compared to an optical displacement meter, the number of sensors 265 used in the distance measurement between the upper wafer W1 can be increased. In addition, when the number of sensors 265 used in the distance measurement between 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 after bonding and the sensor 265, the thickness distribution of the overlapped wafer T can also be accurately measured.

[0091] However, when a capacitance sensor is used as the sensor 265, the object to be measured is usually a conductor and the capacitance sensor and the object to be measured are electrically connected, but it is difficult to satisfy this requirement in conventional bonding apparatuses.

[0092] Therefore, the inventors of the present application have discovered that if a conductive member is used as the main body 260 of the upper holding plate 230 and the sensor 265 is grounded via the main body 260 , the distance between the sensor 265 and the upper wafer W1 can be measured even when there is no conduction between the sensor 265 and the upper wafer W1 . Figure 7 It is an enlarged schematic diagram of the main body 260 of the upper holding plate 230 according to the embodiment, sensors 265A to 265C, and the upper wafer W1. Figure 8 It is shown Figure 7 Graph showing changes in the measurement values ​​of sensors 265A to 265C.

[0093] like Figure 7 As shown, in this experiment, three electrostatic capacitance sensors 265A to 265C are used to measure the distance from the main body 260 to the upper wafer W1. The main body 260 is arranged facing the upper wafer W1 in a non-contact manner. The main body 260 is formed by a conductive member, and the sensors 265A to 265C are grounded via the main body 260. In addition, an insulating sheet can also be provided between the main body 260 and the upper wafer W1 so that the upper wafer W1 and the main body 260 are not conductive.

[0094] exist Figure 8 In FIG. 1 , the vertical axis represents the distance between the upper wafer W1 and the sensors 265A to 265C. Figure 8 These are experimental results when the distances between the upper wafer W1 and the sensors 265A to 265C are changed in the same manner, that is, when the main body 260 is moved parallel to the upper wafer W1 .

[0095] like Figure 8 As shown, as the distance between the upper wafer W1 and the sensors 265A-265C increases, the measurement values ​​of the sensors 265A-265C increase.

[0096] Like this, according to Figure 8 The experimental results shown show that if a conductive member is used as the main body 260 of the upper holding plate 230 and the sensor 265 is grounded via the main body 260 , the distance between the sensor 265 and the upper wafer W1 can be measured.

[0097] Therefore, the sensor 265 in the bonding device 41 involved in the embodiment is grounded via the main body 260. In addition, the main body 260 is formed by a conductive member. As a conductive member, a metal material, a ceramic having conductivity, etc. can be used, but it is not limited to these. As an example, the main body 260 can be formed of aluminum. In addition, the main body 260 can also be subjected to surface treatment such as antistatic coating.

[0098] The plurality of sensors 265 provided in the main body 260 use electrostatic capacitance sensors. Figure 6As shown, a plurality of sensors 265 are arranged radially on the lower surface of the main body 260. Specifically, compared with the 90-degree direction, the bonding wave expands rapidly in the 45-degree direction. The 90-degree direction refers to the direction of a 90-degree period based on the direction from the center of the upper wafer W1 to the [0-11] crystal direction parallel to the surface of the upper wafer W1 (the directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees). The 45-degree direction refers to the direction of a 90-degree period based on the direction from the center of the upper wafer W1 to the

[010] crystal direction parallel to the surface of the upper wafer W1 (the directions of 45 degrees, 135 degrees, 225 degrees, and 315 degrees). A plurality of sensors 265 are arranged along the 90-degree direction and the 45-degree direction.

[0099] The area of ​​the facing surface of the main body 260 facing the upper wafer W1 can be the same as the area of ​​the facing surface of the upper wafer W1 facing the main body 260, or larger than the area of ​​the facing surface of the upper wafer W1 facing the main body 260. Although the main body 260 and the upper wafer W1 are non-contacting, the sensor 265 can detect an electrostatic capacitance sufficient for distance measurement due to the large facing area between the conductive main body 260 and the upper wafer W1. Therefore, the distance to the upper wafer W1 can be measured without achieving conduction between the upper wafer W1 as the measurement object and the sensor 265.

[0100] The lower holding plate 231 may be formed of an insulating (non-conductive) member. If the lower holding plate 231 is formed of a conductive member, there is a possibility that the sensor 265 and the lower holding plate 231 are connected, and the electrostatic capacitance detected by the sensor 265 is unstable, resulting in an unstable measurement value. Therefore, by forming the lower holding plate 231 with an insulating member, such a possibility can be reduced. As an insulating member, for example, alumina ceramics, silicon nitride, etc. can be used, but it is not limited to these.

[0101] <Specific Operations of the Joint System>

[0102] Next, refer to Fig. 9 The specific operation of the joining system 1 according to the embodiment will be described. Fig. 9 It is a flowchart showing the procedure of processing executed by the joining system 1 according to the embodiment. Fig. 9 The various processes shown are executed based on the control of the control device 70 .

[0103] First, a cassette C1 containing a plurality of upper wafers W1, a cassette C2 containing a plurality of lower wafers W2, and an empty cassette C3 are placed on a predetermined placement plate 11 of the loading / unloading station 2. Then, the upper wafer W1 in the cassette C1 is taken out by the transfer device 22 and transferred to a conveyor device disposed in the third processing block G3.

[0104] Next, the upper wafer W1 is transported to the surface modification device 30 of the first processing block G1 by the transport device 61. In the surface modification device 30, oxygen gas as a processing gas is excited to be plasma-formed and ionized under a predetermined reduced pressure atmosphere. The oxygen ions are irradiated to the bonding surface of the upper wafer W1 to perform plasma treatment on the bonding surface. Thus, the bonding surface of the upper wafer W1 is modified (step S101).

[0105] Next, the upper wafer W1 is transported to the surface hydrophilization device 40 of the first processing block G1 by the transport device 61. In the surface hydrophilization device 40, while rotating the upper wafer W1 held on the rotating holding disk, pure water is supplied to the upper wafer W1. Thus, the bonding surface of the upper wafer W1 is hydrophilized. In addition, the bonding surface of the upper wafer W1 is cleaned with the pure water (step S102).

[0106] Next, the upper wafer W1 is transferred to the bonding device 41 of the second processing block G2 by the transfer device 61. The upper wafer W1 transferred to the bonding device 41 is transferred to the position adjustment mechanism 210 by the conveyor 200, and the position adjustment mechanism 210 adjusts the horizontal orientation of the upper wafer W1 (step S103).

[0107] After that, the upper wafer W1 is transferred from the position adjustment mechanism 210 to the flip mechanism 220, and the flip mechanism 220 flips the front and back sides of the upper wafer W1 (step S104). Specifically, the bonding surface W1j of the upper wafer W1 is directed downward. Next, the upper wafer W1 is transferred from the flip mechanism 220 to the upper holding disk 230, and the upper holding disk 230 adsorbs and holds the upper wafer W1 (step S105).

[0108] The processing of the lower wafer W2 is repeated with the processing of steps S101 to S105 for the upper wafer W1. First, the lower wafer W2 in the cassette C2 is taken out by the transfer device 22 and transferred to the conveyor device arranged in the third processing block G3.

[0109] Next, the lower wafer W2 is transported by the transport device 61 to the surface modification device 30 to modify the bonding surface W2j of the lower wafer W2 (step S106). Thereafter, the lower wafer W2 is transported by the transport device 61 to the surface hydrophilization device 40 to hydrophilize the bonding surface W2j of the lower wafer W2 and clean the bonding surface (step S108).

[0110] Thereafter, the lower wafer W2 is transferred to the bonding apparatus 41 by the transfer device 61. The lower wafer W2 transferred to the bonding apparatus 41 is transferred to the position adjustment mechanism 210 by the conveyor 200. Then, the horizontal orientation of the lower wafer W2 is adjusted by the position adjustment mechanism 210 (step S108).

[0111] Thereafter, the lower wafer W2 is transferred to the lower holding plate 231 , and the lower wafer W2 is suction-held on the lower holding plate 231 in a state where the notch portion of the lower wafer W2 faces a predetermined direction (step S109 ).

[0112] Next, the position adjustment in the horizontal direction between the upper wafer W1 held on the upper holding disk 230 and the lower wafer W2 held on the lower holding disk 231 is performed (step S110). Afterwards, the lower wafer W2 is raised using the first moving part 250 to join the upper wafer W1 with the lower wafer W2 (step S111). Specifically, first, after raising the lower wafer W2, the pressing pin 281 of the striker 280 is used to press the center of the upper wafer W1 from top to bottom to make it contact with the center of the lower wafer W2, thereby starting the joining between the central parts. Afterwards, between the upper wafer W1 and the lower wafer W2, a joining wave is generated in which the joining area expands from the center of the upper wafer W1 and the lower wafer W2 toward the periphery. Afterwards, the joining surface W1j of the upper wafer W1 and the joining surface W2j of the lower wafer W2 are in contact with the entire surface, and the upper wafer W1 and the lower wafer W2 are joined.

[0113] In addition, in step S111, a plurality of sensors 265 are used to detect the distance of the upper wafer W1, to measure the progress of the bonding wave, and to check the bonding state between the upper wafer W1 and the lower wafer W2. As described above, the plurality of sensors 265 are arranged along the radial direction of the upper wafer W1. The bonding device 41 can detect the distance between the sensor 265 and the upper wafer W1 at a plurality of points along the radial direction of the upper wafer W1, and observe the boundary position between the bonding area of ​​the upper wafer W1 and the lower wafer W2 and the unbonded area located outside the bonding area based on the detected distance.

[0114] As described above, in the bonding device 41 according to the embodiment, the main body 260 of the upper holding plate 230 is formed of a conductive member, and the sensor 265 is grounded via the main body 260. According to this structure, the distance to the upper wafer W1 can be measured without achieving conduction between the upper wafer W1 as the measurement object and the sensor 265. In addition, since the upper wafer W1 is a semiconductor, the distance can be measured using the sensor 265 even when the measurement object is not a conductor.

[0115] In addition, in the embodiment, the upper wafer W1 is described as an example of a measurement object, but the measurement object is not limited to this. For example, the measurement object may also be a conductor. In this case, the distance to the measurement object can be measured without achieving conduction between the measurement object and the sensor 265.

[0116] Furthermore, the present disclosure can also have the following structures.

[0117] (1) A distance measuring device comprising:

[0118] A first member is arranged to face a measurement object that is a conductor or a semiconductor in a non-contact manner; and

[0119] an electrostatic capacitance sensor provided on the first member and detecting a distance to the measurement object;

[0120] The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

[0121] (2) A distance measuring device according to (1), wherein:

[0122] A plurality of the above-mentioned electrostatic capacitance sensors are provided.

[0123] (3) The distance measuring device according to (1) or (2), wherein:

[0124] An area of ​​a surface of the first member that faces the object to be measured is the same as or larger than an area of ​​a surface of the object to be measured that faces the first member.

[0125] (4) A distance measurement method comprising the following steps:

[0126] A first member and an electrostatic capacitance sensor are used to measure the distance to a measurement object which is a conductor or a semiconductor. The first member is arranged opposite to the measurement object in a non-contact manner. The first member is formed by a conductive member. The electrostatic capacitance sensor is arranged on the first member to detect the distance to the measurement object. The electrostatic capacitance sensor is grounded via the first member.

[0127] (5) A bonding device comprising:

[0128] A first holding portion that sucks and holds the first substrate from above;

[0129] a second holding portion, which is disposed below the first holding portion and holds the second substrate by suction from below; and

[0130] a pressing member, which is disposed on the first holding portion and is used to press a central portion of the first substrate,

[0131] Wherein, the first holding portion comprises:

[0132] A first member is disposed facing the first substrate in a non-contact manner; and

[0133] an electrostatic capacitance sensor, which is provided on the first member and detects the distance between the first member and the first substrate,

[0134] The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

[0135] (6) The bonding device according to (5), wherein:

[0136] An area of ​​a surface of the first member that faces the first substrate is the same as or larger than an area of ​​a surface of the first substrate that faces the first member.

[0137] (7) The bonding device according to (5) or (6), wherein:

[0138] The second holding portion is formed of an insulating member.

[0139] (8) The bonding device according to any one of (5) to (7), wherein:

[0140] A plurality of the electrostatic capacitance sensors are arranged along the radial direction of the first member,

[0141] The bonding apparatus includes a control unit that detects the distance of the first substrate using the plurality of capacitance sensors to observe a boundary position between a bonding region where the first substrate and the second substrate are bonded and an unbonded region outside the bonding region.

[0142] (9) A bonding method comprising the following steps:

[0143] Using a first holding portion to hold the first substrate from above by suction, the first holding portion is a holding portion that holds the first substrate from above by suction, the first holding portion comprising a first member arranged to face the first substrate in a non-contact manner, and an electrostatic capacitance sensor provided on the first member to detect a distance between the first member and the first substrate;

[0144] Using a second holding portion to hold the second substrate from below by suction, the second holding portion being arranged at a position lower than the first substrate, and holding the second substrate from below by suction;

[0145] using a pressing member to press a central portion of the first substrate held by suction by the first holding portion, the pressing member being provided at the first holding portion and used to press the central portion of the first substrate; and

[0146] using the electrostatic capacitance sensor to detect the distance to the first substrate,

[0147] The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

[0148] (10) The joining method according to (9), wherein:

[0149] The first holding portion includes a plurality of the electrostatic capacitance sensors arranged along a radial direction of the first member,

[0150] The bonding method includes the step of observing, based on the distance detected in the step of detecting, a boundary position between a bonding region where the first substrate and the second substrate are bonded and an unbonded region located outside the bonding region.

[0151] It should be considered that all points of the embodiments disclosed this time are illustrative and non-restrictive. In fact, the above-mentioned embodiments can be specifically implemented in a variety of ways. In addition, the above-mentioned embodiments can also be omitted, replaced, and changed in various ways without departing from the attached claims and their gist.

[0152] Description of Reference Numerals

[0153] 1: bonding system; 30: surface modification device; 40: surface hydrophilization device; 41: bonding device; 70: control device; 71: control unit; 230: upper holding plate; 231: lower holding plate; 235: upper camera unit; 236: lower camera unit; 250: first moving unit; 253: second moving unit; 255: mounting table; 256: position adjustment unit; 260: main body; 265: sensor; 266: through hole; 270: supporting member; 280: striker; 281: pressing pin.

Claims

1. A distance measuring device comprising: A first member is arranged to face a measurement object that is a conductor or a semiconductor in a non-contact manner; and an electrostatic capacitance sensor provided on the first member and detecting a distance to the measurement object; in, The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

2. The distance measuring device according to claim 1, wherein: A plurality of the above-mentioned electrostatic capacitance sensors are provided.

3. The distance measuring device according to claim 1, wherein: An area of ​​a surface of the first member that faces the object to be measured is the same as or larger than an area of ​​a surface of the object to be measured that faces the first member.

4. A distance measurement method, comprising the following steps: A first member and an electrostatic capacitance sensor are used to measure the distance to a measurement object which is a conductor or a semiconductor. The first member is arranged opposite to the measurement object in a non-contact manner. The first member is formed by a conductive member. The electrostatic capacitance sensor is arranged on the first member to detect the distance to the measurement object. The electrostatic capacitance sensor is grounded via the first member.

5. A bonding device comprising: A first holding portion that sucks and holds the first substrate from above; a second holding portion, which is disposed below the first holding portion and holds the second substrate by suction from below; and a pressing member, which is disposed on the first holding portion and is used to press a central portion of the first substrate, in, The first holding portion comprises: A first member is disposed facing the first substrate in a non-contact manner; and an electrostatic capacitance sensor, which is provided on the first member and detects the distance between the first member and the first substrate, The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

6. The joining device according to claim 5, wherein: An area of ​​a surface of the first member that faces the first substrate is the same as or larger than an area of ​​a surface of the first substrate that faces the first member.

7. The joining device according to claim 5, wherein: The second holding portion is formed of an insulating member.

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

9. A bonding method comprising the following steps: Using a first holding portion to hold the first substrate from above by suction, the first holding portion is a holding portion that holds the first substrate from above by suction, the first holding portion comprising a first member arranged to face the first substrate in a non-contact manner, and an electrostatic capacitance sensor provided on the first member to detect a distance between the first member and the first substrate; Using a second holding portion to hold the second substrate from below by suction, the second holding portion being arranged at a position lower than the first substrate, and holding the second substrate from below by suction; Using a pressing member to press the central portion of the first substrate held by the first holding portion, wherein the pressing member is provided at the first holding portion and is used to press the central portion of the first substrate; as well as using the electrostatic capacitance sensor to detect the distance to the first substrate, The first member is formed of a conductive member, and the electrostatic capacitance sensor is grounded via the first member.

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

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