JP6165102B2 - Joining apparatus, joining system, joining method, program, and information storage medium - Google Patents

Description

  The present invention relates to a bonding apparatus, a bonding system, a bonding method, a program, and an information storage medium.

  In recent years, a three-dimensional integration technique has been proposed as a high integration technique for semiconductor devices. In the three-dimensional integration technique, a bonding apparatus (for example, refer to Patent Document 1) for bonding two semiconductor wafers (hereinafter referred to as “wafer”) is used.

  The bonding apparatus bonds the two wafers with the bonding surfaces of the two wafers facing each other. The bonding apparatus captures images of two wafers using the two imaging units and aligns the two wafers using the images of the two wafers before superimposing the two wafers.

  In order to improve the alignment accuracy, the bonding apparatus performs alignment after correcting the relative position information of the two imaging units by causing the two imaging units to image a common target.

International Publication No. 2010/038454

  The target is composed of a pinhole or the like, and is moved from an imaging position where the image is captured by the imaging unit to a retreat position where the image is not captured by the imaging unit so as not to interfere with the imaging of the wafer. A drive unit that moves the target, a stopper that stops the target at the imaging position, and the like are used.

  Conventionally, vibration and deformation of the drive unit and the stopper have occurred, and the wafer alignment accuracy has been low.

  The present invention has been made in view of the above problems, and a main object of the present invention is to provide a bonding apparatus that improves the alignment accuracy of a substrate such as a wafer.

In order to solve the above problems, according to one aspect of the present invention,
A bonding apparatus for bonding the first substrate and the second substrate with the bonding surface of the first substrate facing the bonding surface of the second substrate,
A first holding unit for holding the first substrate;
A second holding unit for holding the second substrate;
A first imaging unit that captures an image of the second substrate held by the second holding unit;
A second imaging unit that captures an image of the first substrate held by the first holding unit;
A driving unit that relatively moves the first holding unit and the second holding unit, and relatively moves the first imaging unit and the second imaging unit;
A light source that emits light to the first imaging unit and the second imaging unit;
A controller that controls the drive unit based on the image of the first substrate and the image of the second substrate to align the first substrate and the second substrate;
The control unit causes the first imaging unit and the second imaging unit to capture an image of light from the light source, and corrects relative positional information between the first imaging unit and the second imaging unit; A joining device is provided.

  According to one embodiment of the present invention, a bonding apparatus with improved substrate alignment accuracy is provided.

It is a top view which shows the outline of the joining system by one Embodiment. It is a side view showing the outline of the joining system by one embodiment. It is sectional drawing perpendicular | vertical with respect to the Z direction of the joining apparatus by one Embodiment. It is sectional drawing perpendicular | vertical with respect to the X direction of the joining apparatus by one Embodiment. It is a flowchart which shows the main processes of the joining method by one Embodiment. It is a flowchart which shows the detailed process of the joining process of FIG. It is a side view which shows an example of the positional relationship of an upper optical unit and a lower optical unit when making the lower image pick-up part image the image of the light from a lower light source. It is a side view which shows an example of the positional relationship of an upper optical unit and a lower optical unit when making the upper imaging part image the light from a lower light source. It is a side view which shows an example of the positional relationship of an upper optical unit and a lower optical unit when making the upper image pick-up part image the light from an upper light source. It is a side view which shows an example of the positional relationship of an upper optical unit and a lower optical unit when making a lower imaging part image the image of the light from an upper light source. It is a side view which shows an example of the positional relationship of an upper chuck | zipper and a lower chuck | zipper when imaging reference | standard point A1 and reference | standard point B1. It is a top view which shows an example of the positional relationship of an upper chuck | zipper and a lower chuck | zipper when imaging reference | standard point A1 and reference | standard point B1. It is a side view which shows an example of the positional relationship of an upper chuck | zipper and a lower chuck | zipper when imaging reference point A2 and reference point B2. It is a top view which shows an example of the positional relationship of an upper chuck | zipper and a lower chuck | zipper when imaging reference | standard point A2 and reference | standard point B2. It is a top view which shows an example of the positional relationship of the upper chuck | zipper and lower chuck | zipper at the time of a wafer superimposition process start. It is a side view which shows the state which joined the center part of the upper wafer, and the center part of the lower wafer. It is a side view which shows the state which joined the whole upper wafer and the whole lower wafer. It is a side view which shows the upper optical unit and lower optical unit by a modification.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof is omitted. In the following description, the X direction, the Y direction, and the Z direction are directions perpendicular to each other, the X direction and the Y direction are horizontal directions, and the Z direction is a vertical direction.

  FIG. 1 is a plan view schematically showing a joining system according to an embodiment. FIG. 2 is a side view schematically illustrating a bonding system according to an embodiment.

The interface system 1 is facing the joint surface and the bonding surface of the wafer W _L of the wafer W _U, bonding the wafer W _U and the wafer W _L. It overlapped wafer _{W T} composed of the wafer _{W U} and the wafer _{W L} is obtained. The wafers W _U and W _L may be formed with elements, circuits, terminals, and the like. Further, the wafers W _U and W _L may be superposed wafers formed by bonding a plurality of wafers. The joining system 1 includes a carry-in / out station 2, a processing station 3, and a control device 5.

Cassettes C _U , C _L , and _CT are carried into and out of the carry-in / out station 2 from the outside. The cassette _{C U} a wafer _{W U,} the cassette _{C L} is a wafer _{W L,} the cassette _{C T} is respectively accommodate a plurality of overlapped wafer _{W T.} Overlapped wafer W _T is identified in the molded product is good or defective, and the cassette C _T for good, may be housed separately in a cassette C _T for defective products. The carry-in / out station 2 includes a cassette mounting table 10 and a wafer transfer device 20.

The cassette mounting table 10 includes a plurality of (for example, four) cassette mounting plates 11. The plurality of cassette mounting plates 11 are arranged in a line in the X direction. Cassettes C _U , C _L , and _CT are placed on the cassette mounting plate 11. The number of cassette mounting plates 11 is not limited to four.

The wafer transfer device 20, a cassette _C U on the cassette mounting plate _11, C L, and _{C T,} between the processing station 3, conveys the wafer _W U, _{W L,} the overlapped wafer _{W T.} The wafer transfer apparatus 20 includes a transfer path 21 and a transfer arm 22 that is movable in the X direction along the transfer path 21. The transfer arm 22 may be movable in the Z direction, and may be rotatable about a rotation axis parallel to the Z direction.

  The processing station 3 includes a first processing block G1, a second processing block G2, and a third processing block G3. A wafer transfer region is formed between the first processing block G1 to the third processing block G3, and the wafer transfer device 60 is disposed in the wafer transfer region. The first processing block G1 and the second processing block G2 are disposed on opposite sides in the X direction with the wafer transfer device 60 interposed therebetween. The third processing block G3 is disposed between the wafer transfer device 60 and the wafer transfer device 20.

The first processing block G1 includes a surface modification device 30 that modifies the bonding surfaces of the wafers W _U and W _L. The surface modification device 30 may be a plasma processing device, for example. The plasma processing apparatus, for example, converts oxygen gas as a processing gas into a plasma under a reduced pressure atmosphere and irradiates oxygen ions to the bonding surface. The plasma processing conditions may vary widely. For example, the processing gas may be argon gas.

  The second processing block G2 includes the surface hydrophilizing device 40 and the joining device 41 in this order from the carry-in / out station 2 side. As shown in FIG. 1, the surface hydrophilizing device 40 and the joining device 41 are arranged in the Y direction.

The surface hydrophilizing device 40 hydrophilizes the joint surface modified by the surface modifying device 30. Surface hydrophilizing apparatus 40, the wafer W _U held by the spin _chuck, while rotating the W _L, for supplying pure water to the bonding surface of the wafer W _U, W _L. Hydroxyl groups (silanol groups) as hydrophilic groups adhere to the bonding surface, making the bonding surface hydrophilic. Further, the joint surface is washed with pure water.

The bonding apparatus 41 bonds the wafers W _U and W _L with the bonding surfaces hydrophilized by the surface hydrophilizing apparatus 40 facing each other. The bonding apparatus 41 may sequentially bond the wafers W _U and W _L from the central portion toward the outer peripheral portion in order to suppress trapping of bubbles during bonding. Wafer _W U, overlapped wafer _{W T} is obtained consisting of _{W L.} Details of the bonding apparatus 41 will be described later.

The third processing block G3 includes transition devices 50 and 51 as shown in FIG. The transition devices 50 and 51 may be stacked in the Z direction. Transition unit 50 and 51, the wafer _W U, _{W L,} the polymerization to temporarily store the wafer _{W T,} and passes the wafer transfer unit 20 and the wafer transfer apparatus 60.

The wafer transfer device 60 includes a transfer arm 61 that transfers the wafers W _U and W _L and the overlapped wafer W _T. The transfer arm 61 is movable in, for example, the X direction, the Y direction, and the Z direction, and is rotatable about a rotation axis parallel to the Z direction. The transfer arm 61 transfers the wafers W _U and W _L and the overlapped wafer W _T to the first processing block G1, the second processing block G2, and the third processing block G3.

  The control device 5 is configured by a computer including a storage unit such as a memory and a CPU (Central Processing Unit), and implements various processes by causing the CPU to execute a program (also referred to as a recipe) stored in the storage unit. . In addition, although the control apparatus 5 is provided separately from the joining apparatus 41 in this embodiment, a part of the joining apparatus 41 may be sufficient. The control device 5 corresponds to the control unit described in the claims.

  The program of the control device 5 is stored in the information storage medium and installed from the information storage medium. Examples of the information storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical desk (MO), and a memory card. The program may be downloaded from a server via the Internet and installed.

  FIG. 3 is a cross-sectional view perpendicular to the Z direction of a bonding apparatus according to an embodiment. FIG. 4 is a cross-sectional view perpendicular to the X direction of the bonding apparatus according to the embodiment.

  As shown in FIG. 3, the bonding apparatus 41 includes a processing container 100 that can seal the inside. A loading / unloading port 101 is formed on the side surface of the processing container 100 on the wafer transfer apparatus 60 side, and an opening / closing shutter 102 is provided at the loading / unloading port 101. The inside of the processing container 100 is partitioned by a partition wall 103 into a transport area T1 and a processing area T2. A loading / unloading port 104 is formed in the partition wall 103.

  The bonding apparatus 41 includes a transition 110, a wafer transfer mechanism 111, a position adjustment mechanism 120, a reversing mechanism 130, and the like in the transfer region T1.

Transitions 110, temporarily placing the overlapped wafer _{W T} to be carried out to the wafer transfer unit 60 via a wafer _W U, _{W L} and unloading port 101, which is carried from the wafer transfer unit 60 via the transfer port 101 To do. The transition 110 is formed in, for example, two stages, and any two of the wafers W _U , W _L , and the superposed wafer W _T can be placed at the same time.

The wafer transfer mechanism 111 has, for example, a transfer arm 112 as shown in FIG. The transfer arm 112 is movable in the X direction, the Y direction, and the Z direction, and is rotatable about a rotation axis parallel to the Z direction. The transfer arm 112 can transfer the wafers W _U and W _L and the overlapped wafer W _T in the transfer region T1 or between the transfer region T1 and the processing region T2.

The position adjustment mechanism 120 adjusts the orientation of the wafers W _U and W _{L in} the horizontal plane. Position adjusting mechanism 120 has a holding portion 122 and the detection unit 123, the wafer _W U which is horizontally held in the holder 122, the wafer by the detection unit 123 while rotating the _{W L} in a horizontal plane _W U, _{W L} By detecting the position of the notch portion, the orientation of the wafers W _U and W _{L in} the horizontal plane is adjusted.

The reversing mechanism 130 reverses the wafer W _U so that the bonding surface of the wafer W _U faces downward, and delivers the wafer W _U to the upper chuck 141 disposed in the processing region T2. The reversing mechanism 130 has a holding arm 131 and a rotating shaft 134. The center line of the holding arm 131 is horizontal, and the center line of the rotating shaft 134 is vertical.

Reversing mechanism 130 inverts the wafer W _U held by the holding arm 131 rotates the holding arm 131 about the center line of the holding arm 131. The reversing mechanism 130 moves the holding arm 131 parallel to the center line of the holding arm 131 and rotates the holding arm 131 about the center line of the rotation shaft 134 to thereby hold the wafer held by the holding arm 131. W _U is conveyed below the upper chuck 141. Thereafter, the reversing mechanism 130 raises the holding arm 131 together with the rotating shaft 134, and passes the wafer _{W U} from the holding arm 131 on the chuck 141.

  The bonding apparatus 41 includes an upper stage 140, a lower stage 150, an upper optical unit 160, a lower optical unit 170, and the like in the processing region T2.

The upper stage 140 includes an upper chuck 141 and an upper chuck support portion 142. Upper chuck 141 toward the lower bonding surfaces of the wafers W _U, the bonding surface of the wafer W _U holds the surface on the opposite side. Hereinafter, the wafer W _U held by the upper chuck 141 is also referred to as an upper wafer W _U. Upper chuck 141, the upper wafer _{W U} may be vacuum suction. The upper chuck 141 is fixed to the ceiling of the processing container 100 via the upper chuck support part 142.

On the upper surface of the upper chuck 141, pressing member 180 for pressing the central portion of the upper wafer _{W U} as shown in FIGS. 15 to 17 are provided. The pushing member 180 includes a pushing pin 181 that is movable in the Z direction, and an outer cylinder 182 that guides the movement of the pushing pin 181. Pushing pin 181 is inserted movably in a through hole 141a of the upper chuck 141, to press the central portion of the upper wafer W _U downward.

As shown in FIGS. 3 and 4, the lower stage 150 includes a lower chuck 151 and a lower chuck driving unit 152. Lower chuck 151 toward the top bonding surface of the wafer W _L, the bonding surface of the wafer W _L for holding the surface opposite. Hereinafter also referred to as a wafer _{W L} held by the lower chuck 151 and lower wafer _{W L.} Lower chuck 151 may be vacuum suction lower wafer _{W L.}

  The lower chuck driving unit 152 moves the lower chuck 151 in order to move the upper chuck 141 and the lower chuck 151 relatively. The lower chuck driving unit 152 includes an X direction driving unit 154, a Y direction driving unit 155, a Z direction driving unit 156, a rotation driving unit, and the like. The X direction drive unit 154 moves the lower chuck 151 in the X direction, the Y direction drive unit 155 moves in the Y direction, and the Z direction drive unit 156 moves in the Z direction. The position of the lower chuck 151 is measured by a position sensor. The position sensor is composed of, for example, a linear scale. The position sensor may be configured with a laser displacement meter or the like, and is not particularly limited. The rotation driving unit rotates the lower chuck 151 around the center line of the lower chuck 151. The rotation angle of the lower chuck 151 is measured by an encoder or the like.

The drive unit that relatively moves the upper chuck 141 and the lower chuck 151 may be provided in both the upper stage 140 and the lower stage 150, but may be provided in only one of them. Reducing the number of driver, vibration and deformation due to the drive unit can be suppressed, thereby improving the positioning accuracy of the upper wafer W _U and _the lower wafer W _L. The drive unit may be provided only in the upper stage 140, but may be provided only in the lower stage 150 as in the present embodiment. Since the upper stage 140 is suspended from the ceiling of the processing container 100, the lower stage 150 is installed on the floor of the processing container 100, so that the driving unit can be easily configured and the driving unit can be downsized.

  The lower chuck driving unit 152 relatively moves the upper chuck 141 and the lower chuck 151 in the X direction, the Y direction, and the Z direction, and moves the upper optical unit 160 and the lower optical unit 170 in the X direction, the Y direction, and the Z direction. Move relative to the direction. The lower chuck driving unit 152 moves the lower optical unit 170 together with the lower chuck 151. The position of the lower optical unit 170 can be measured by a position sensor that measures the position of the lower chuck 151.

  As shown in FIG. 4, the upper optical unit 160 is fixed to the processing container 100 via the upper chuck support part 142 in the same manner as the upper chuck 141.

  The upper optical unit 160 includes an upper imaging unit 161, an upper macro lens 162, an upper micro lens 163, and the like as shown in FIGS. The upper imaging unit 161 is configured by an imaging element such as a CCD image sensor or a CMOS image sensor, and images the lower part via the upper macro lens 162 or the upper micro lens 163. In the case of the upper macro lens 162, an image having a wider imaging range than that of the upper micro lens 163 can be obtained. In the case of the upper microlens 163, an image having a higher resolution than that of the upper macrolens 162 can be obtained.

The upper optical unit 160 further includes an upper reflection unit 164, an upper light source 165, an upper imaging unit side separation unit 166, and an upper microlens side separation unit 167 for optical correction described later. Each of the upper imaging unit side separation unit 166 and the upper microlens side separation unit 167 is configured by a beam splitter or the like, and transmits part of incident light and reflects part of incident light. Incidentally, the upper optical unit 160 in order to capture an image of the lower wafer W _L through the upper macro lens 162 on the image pickup unit 161 further includes a like beam splitters and mirrors.

  As shown in FIGS. 3 and 4, the lower optical unit 170 is connected to the lower chuck driving unit 152 and moves in the X direction, the Y direction, and the Z direction together with the lower chuck 151. The lower optical unit 170 may not rotate with the lower chuck 151.

  The lower optical unit 170 includes a lower imaging unit 171, a lower macro lens 172, a lower micro lens 173, and the like as shown in FIGS. The lower imaging unit 171 is configured by an imaging element such as a CCD image sensor or a CMOS image sensor, and images the upper side via the lower macro lens 172 or the lower micro lens 173. In the case of the lower macro lens 172, an image having a wider imaging range than that in the case of the lower micro lens 173 can be obtained. In the case of the lower microlens 173, an image having a higher resolution than that in the case of the lower macrolens 172 is obtained.

The lower optical unit 170 further includes a lower reflection unit 174, a lower light source 175, a lower imaging unit side separation unit 176, and a lower microlens side separation unit 177 for optical correction described later. The lower imaging unit side separation unit 176 and the lower microlens side separation unit 177 are each configured by a beam splitter or the like, and transmit part of incident light and reflect part of incident light. Incidentally, the lower the optical unit 170, in order to capture an image of the upper wafer W _U under the imaging unit 171 through a lower macro lens 172 further includes a like beam splitters and mirrors.

Next, a method for bonding the wafers W _U and W _L performed using the bonding system 1 will be described. FIG. 5 is a flowchart showing main steps of the bonding method according to the embodiment. Here, illustrating a bonding method by focusing on one of the wafer W _U.

  As shown in FIG. 5, the joining method includes a carry-in process (step S11), a surface modification process (step S13), a surface hydrophilization process (step S15), a joining process (step S17), a carry-out process (step S19), and the like. Have These steps are performed under the control of the control device 5.

The loading step, to carry the wafer W _U to the transition unit 50 from the cassette C _U on the cassette mounting plate 11 by the wafer transfer apparatus 20, then the wafer W surface modification apparatus 30 from the transition unit 50 by the wafer transfer apparatus 60 Transport _U.

The surface modification step, the surface modification apparatus 30 for surface modification the bonding surface of the wafer W _U. For example, the surface reforming apparatus 30 converts the bonding surface into a surface by converting oxygen gas as a processing gas into plasma in a reduced-pressure atmosphere and irradiating the bonding surface with oxygen ions. After the surface modification, the control unit 5 transports the wafers W _U to the surface hydrophilizing apparatus 40 from the surface modifying apparatus 30 controls the wafer transfer apparatus 60.

The surface hydrophilizing step, hydrophilic bonding surfaces of the wafers W _U by surface hydrophilizing device 40. For example, surface hydrophilizing device 40, while rotating the wafer W _U held by the spin chuck, for supplying pure water to the bonding surface of the wafer W _U. Hydroxyl groups (silanol groups) adhere to the bonding surface, making the bonding surface hydrophilic. Further, the joint surface is washed with pure water. After surface hydrophilizing, the control unit 5 transports the wafers W _U to the bonding apparatus 41 from the surface hydrophilizing device 40 controls the wafer transfer apparatus 60.

In this way, the wafer W _U is taken out of the cassette C _U, the surface modification apparatus 30 is sequentially transported to the surface hydrophilizing apparatus 40. Then, the bonding surfaces of the wafers W _U is surface modified are hydrophilic. Thereafter, the wafer _{W U} is transferred to the bonding apparatus 41.

During this time, in the same manner, another wafer W _L is taken out from the cassette C _L, the surface modification apparatus 30 is sequentially transported to the surface hydrophilizing apparatus 40. Then, the bonding surface of the wafer W _L is surface modified are hydrophilic. Thereafter, the wafer _{W L} is transported to the bonding apparatus 41.

Here, the processing of the wafer W _U, the process of the wafer W _L, may be independently performed. For example, the surface modification of the other wafer may be performed while the surface of one wafer is hydrophilized. When a plurality of surface modification devices 30 and surface hydrophilization devices 40 are mounted on the bonding system 1, the same processing may be performed on both wafers simultaneously.

In the bonding step, the wafers W _U and W _L are bonded to each other with the hydrophilic bonding surfaces facing each other. The bonding apparatus 41 may sequentially bond the wafers W _U and W _L from the central portion toward the outer peripheral portion in order to suppress trapping of bubbles during bonding. Wafer _W U, consisting of _{W L} overlapped wafer _{W T} can be obtained. Details of the bonding process will be described later.

The unloading step, conveying the overlapped wafer W _T from the joining apparatus 41 in the transition unit 50 by the wafer transfer apparatus 60, then the cassette C _T in the overlapped wafer W on the cassette mounting plate 11 from the transition unit 50 by the wafer transfer apparatus 20 Transport _T. Cassette C _T is unloaded from the cassette mounting plate 11 to the outside.

  Next, the details of the joining process of FIG. 5 will be described. FIG. 6 is a flowchart showing detailed steps of the joining step of FIG.

  The bonding process includes a wafer setting process (step S21), an optical correction process (step S23), a wafer imaging process (step S25), a wafer alignment process (step S27), a wafer overlay process (step S29), and the like. Good.

The wafer setting step, after adjusting the orientation in the horizontal plane of the wafer W _U by the position adjusting mechanism 120, the reversing mechanism 130 directs down bonding surface of the wafer W _U by inverting the wafer W _U. Then, the wafer W _U is delivered from the reversing mechanism 130 to the upper chuck 141, and the upper chuck 141 holds the wafer W _U.

Further, the wafer setting step, after adjusting the orientation in the horizontal plane of the wafer W _L by the position adjusting mechanism 120, passing the wafer W _L to lower chuck 151 to hold the wafer W _L to lower chuck 151.

  In the optical correction process, both the upper imaging unit 161 and the lower imaging unit 171 are caused to capture an image of light from at least one of the lower light source 175 and the upper light source 165, and the upper imaging unit 161 and the lower imaging unit 171 Relative position information (specifically, the X direction position and the Y direction position) is corrected. At this time, the upper imaging unit 161 may capture an image via the upper microlens 163 in order to obtain an image with high resolution. Similarly, the lower imaging unit 171 may capture an image via the lower microlens 173 in order to obtain an image with high resolution. At this time, the lower light source 175 or the upper light source 165 is turned on. The upper light source 165 and the lower light source 175 are spot light sources, for example, and may be configured by an LED (Light Emitting Diode) and a pinhole through which light from the LED passes.

  FIG. 7 is a side view illustrating an example of a positional relationship between the upper optical unit and the lower optical unit when the lower imaging unit captures an image of light from the lower light source. FIG. 8 is a side view illustrating an example of a positional relationship between the upper optical unit and the lower optical unit when the upper imaging unit captures an image of light from the lower light source. FIG. 9 is a side view illustrating an example of a positional relationship between the upper optical unit and the lower optical unit when the upper imaging unit captures an image of light from the upper light source. FIG. 10 is a side view illustrating an example of a positional relationship between the upper optical unit and the lower optical unit when the lower imaging unit captures an image of light from the upper light source. 7 to 10, a broken line indicates the optical path of light, and an arrow indicates the traveling direction of light.

  The control device 5 compares the images picked up by both the upper image pickup unit 161 and the lower image pickup unit 171, and as shown in FIGS. 8 and 10, the optical axis of the upper microlens 163 and the optical axis of the lower microlens 173. The lower chuck 151 is moved to a position where “and” match. In addition, the control device 5 measures the position of the lower chuck 151 with a position sensor, and sets the measured position as an initial position. In this way, the relative position information between the upper imaging unit 161 and the lower imaging unit 171 is corrected.

  First, referring to FIGS. 7 and 8, both the upper imaging unit 161 and the lower imaging unit 171 are caused to capture an image of light from the lower light source 175, and the relative relationship between the upper imaging unit 161 and the lower imaging unit 171. A description will be given of a case where a typical position information correction is performed.

  The control device 5 controls the lower chuck driving unit 152 to move the position of the lower optical unit 170 to the position shown in FIG. 7, and causes the lower imaging unit 171 to capture an image of light from the lower light source 175. An image captured at this time is used as a reference image. Part of the light from the lower light source 175 is reflected by the lower microlens side separation unit 177, passes through the lower microlens 173, is reflected by the upper reflection unit 164, passes through the lower microlens 173 again, and passes through the lower microlens. The light passes through the side separation unit 177, is reflected by the lower imaging unit side separation unit 176, and is imaged by the lower imaging unit 171. At this time, the focus of the lower microlens 173 may be on the horizontal reflecting surface 164a of the upper reflecting portion 164, and the light from the lower light source 175 may be condensed on the reflecting surface 164a. The condensing position may be anywhere within the reflecting surface 164a, and positional deviation in the X direction and the Y direction can be allowed.

  Next, the control device 5 controls the lower chuck driving unit 152 to change the position of the lower optical unit 170, and causes the upper imaging unit 161 to capture the light from the lower light source 175 as illustrated in FIG. Part of the light from the lower light source 175 is reflected by the lower microlens side separation unit 177, passes through the lower microlens 173 and the upper microlens 163, passes through the upper microlens side separation unit 167, and is on the upper imaging unit side. The light is reflected by the separation unit 166 and captured by the upper imaging unit 161. At this time, the focal point of the lower microlens 173 and the focal point of the upper microlens 163 may be on the same horizontal plane.

  The control device 5 compares the image of the upper imaging unit 161 with the reference image of the lower imaging unit 171 and moves the lower chuck 151 to a position where the optical axis of the upper microlens 163 and the optical axis of the lower microlens 173 coincide. . In addition, the control device 5 measures the position of the lower chuck 151 with a position sensor, and sets the measured position as an initial position.

  Next, referring to FIG. 9 and FIG. 10, both the upper imaging unit 161 and the lower imaging unit 171 are caused to capture an image of light from the upper light source 165, and the upper imaging unit 161 and the lower imaging unit 171. A case where relative position information is corrected will be described.

  The control device 5 controls the lower chuck driving unit 152 to move the position of the lower optical unit 170 to the position shown in FIG. 9 and cause the upper imaging unit 161 to capture an image of light from the upper light source 165. An image captured at this time is used as a reference image. Part of the light from the upper light source 165 is reflected by the upper microlens side separation unit 167, passes through the upper microlens 163, is reflected by the lower reflection unit 174, passes through the upper microlens 163 again, and passes through the upper microlens. The light passes through the side separation unit 167, is reflected by the upper imaging unit side separation unit 166, and is imaged by the upper imaging unit 161. At this time, the focus of the upper microlens 163 may be on the horizontal reflecting surface 174a of the lower reflecting portion 174, and the light from the upper light source 165 may be condensed on the reflecting surface 174a. The condensing position may be anywhere as long as it is within the reflecting surface 174a, and positional deviation in the X direction and the Y direction can be allowed.

  Next, the control device 5 controls the lower chuck driving unit 152 to change the position of the lower optical unit 170 and cause the lower imaging unit 171 to capture the light from the upper light source 165 as shown in FIG. Part of the light from the upper light source 165 is reflected by the upper microlens side separation unit 167, passes through the upper microlens 163 and the lower microlens 173, passes through the lower microlens side separation unit 177, and is on the lower imaging unit side The light is reflected by the separation unit 176 and imaged by the lower imaging unit 171. At this time, the focal point of the lower microlens 173 and the focal point of the upper microlens 163 may be on the same horizontal plane.

  The control device 5 compares the image of the lower imaging unit 171 with the reference image of the upper imaging unit 161 and moves the lower chuck 151 to a position where the optical axis of the upper microlens 163 and the optical axis of the lower microlens 173 coincide. . In addition, the control device 5 measures the position of the lower chuck 151 with a position sensor, and sets the measured position as an initial position.

  The position of the upper imaging unit 161 and the position of the upper light source 165 may be reversed. Further, the position of the lower imaging unit 171 and the position of the lower light source 175 may be reversed. Furthermore, in this embodiment, in order to correct the initial position, the lower chuck 151 is moved to a position where the optical axis of the upper microlens 163 and the optical axis of the lower microlens 173 coincide with each other. The control device 5 can measure the positional deviation in the X direction and the Y direction between the optical axis of the upper microlens 163 and the optical axis of the lower microlens 173 by image processing. In the present embodiment, the upper optical unit includes a reflection unit that reflects light from the lower light source 175 toward the lower imaging unit 171, but the lower optical unit may include the reflection unit. Similarly, although the lower optical unit includes a reflection unit that reflects light from the upper light source 165 toward the upper imaging unit 161, the upper optical unit may include the reflection unit.

The wafer image pickup step, causes image the lower wafer W _L on the imaging unit 161, thereby capturing the upper wafer W _U under the imaging section 171. This allows obtaining the relative position information of the upper wafer W _U and _the lower wafer W _L. So as not to interfere with the time of imaging of the upper wafer W _U and the lower wafer W _L, upper light sources 165 and the lower light source 175 is turned off.

First, the control unit 5, by imaging, etc. outer periphery of the outer peripheral portion and the lower wafer W _L of the upper wafer W _U, the rough data of the relative position information of the upper wafer W _U and the lower wafer W _L get. At this time, the upper macro lens 162 and the lower macro lens 172 are used so that an image with a wide imaging range can be obtained.

Controller 5 controls the lower chuck driving unit 152, by changing the position of the lower chuck 151, is imaged at least three points of the outer periphery of the lower wafer W _L on the imaging unit 161, the captured image image processed to calculate the center position of the lower wafer W _L. For this calculation, the position of the lower chuck 151 measured by the position sensor during imaging is also used. Thereafter, the control unit 5 causes the image the center and its adjacent portion of the lower wafer W _L on the imaging unit 161, a captured image by image processing, pattern of the lower wafer W _L (e.g. the lower wafer W _L etc. pattern forming chips) to calculate the direction in the horizontal plane of the lower wafer W _L.

Similarly, the control unit 5 controls the lower chuck driving unit 152, by changing the position of the lower imaging unit 171, is captured at least three points of the outer peripheral portion of the upper wafer W _U under the imaging unit 171 is imaged the image is subjected to image processing, it calculates the center position of the upper wafer W _U. For this calculation, the position of the lower imaging unit 171 measured by the position sensor at the time of imaging is also used. Thereafter, the control unit 5, the center and its adjacent portion of the upper wafer W _U is imaged under the imaging section 171, a captured image by image processing, the upper wafer W _U pattern (e.g. upper wafer W _U calculate the direction in the horizontal plane of the upper wafer W _U formed pattern of the chip) and the like.

Thus, the control unit 5, the orientation and the center position in the horizontal plane of the lower wafer W _L, and calculates the direction and the center position in the horizontal plane of the upper wafer W _{U, the} upper wafer W _U and _the lower wafer W _L Relative position information is roughly obtained. Thus, the position of the reference point above the wafer W position and the lower wafer of the reference point of the _U W _L can be obtained roughly. Three or more reference points are formed in advance on each joint surface. A part of a pattern such as a chip may be used as the reference point.

Then, the control unit 5, by imaging, etc. reference point of the upper wafer W _U reference point and the lower wafer W _L of the precise data of the relative position information of the upper wafer W _U and the lower wafer W _L get. At this time, the upper microlens 163 and the lower microlens 173 are used so that an image with high resolution can be obtained.

11 and 12 are diagrams showing the positional relationship between the upper chuck and the lower chuck when the reference point A1 and the reference point B1 are imaged. FIGS. 13 and 14 are diagrams showing the positional relationship between the upper chuck and the lower chuck when imaging the reference point A2 and the reference point B2. Three reference points of the upper wafer W _U A1 to A3 are, in this embodiment, but are aligned on the same straight line, there may be no side by side on the same straight line. Similarly, three reference points B1~B3 the lower wafer W _L is, in this embodiment, but are aligned on the same straight line, there may be no side by side on the same straight line.

The control device 5 controls the lower chuck driving unit 152 to change the positions of the lower chuck 151 and the lower imaging unit 171 as shown in FIGS. The position of each reference point is calculated by image processing the obtained image. For this calculation, the position of the lower chuck 151 and the position of the lower imaging unit 171 measured by the position sensor during imaging are also used. Then, accurate data of the relative position information of the upper wafer W _U and the lower wafer W _L is obtained.

The wafer alignment step, so that the reference point A1~A3 the upper wafer _{W U} and the reference point B1~B3 the lower wafer _{W L} overlap as viewed in the Z direction, and controls the lower chuck driving unit 152, the upper wafer W to align the _U and the lower wafer W _L. In this alignment, the X-direction position, the Y-direction position, and the rotation position of the lower chuck 151 are adjusted. The rotation position is a rotation position around a rotation axis parallel to the Z direction.

In step superposed wafer, overlapping the wafer W _U and the lower wafer W _L after being aligned in a wafer alignment step. FIG. 15 is a plan view showing an example of the positional relationship between the upper chuck and the lower chuck at the start of the wafer overlaying process. FIG. 16 is a side view showing a state in which the center portion of the upper wafer and the center portion of the lower wafer are joined. FIG. 17 is a side view showing a state in which the entire upper wafer and the entire lower wafer are joined.

First, the control unit 5 controls the lower chuck driving unit 152, the distance between the upper wafer W _U and _the lower wafer W _L and a predetermined distance as shown in FIG. 15. Subsequently, the control unit 5, by lowering the pressing pin 181 as shown in FIG. 16, to press the central portion of the upper wafer W _U.

Then, the deformed the upper wafer W _U, the central portion of the upper wafer W _U projects downward from the outer peripheral portion of the upper wafer W _U. At this time, the outer peripheral portion of the upper wafer W _U is held by the upper chuck 141. In a state where gaps are formed between the outer portion of the outer peripheral portion and the lower wafer W _L of the upper wafer W _U, the central portion of the upper wafer W _U it is pressed against the center of the lower wafer W _L.

Because it is reformed each modified bonding surface of the upper wafer W _U joint surface and the lower wafer W _L of van der Waals forces is formed between the joining faces. Further, since the bonding surface of the upper wafer W _U joint surface and the lower wafer W _L of it is respectively hydrophilic, between hydrophilic groups are hydrogen bonds. By van der Waals forces or hydrogen bonds, and the central portion of the central portion and the lower wafer W _L of the upper wafer W _U it is bonded.

Then, the control unit 5 releases the vacuum suction of the upper wafer W _U by the upper chuck 141 while pressing the center portion of the upper wafer W _U by pressing member 180. At this time, the control unit 5 may be released sequentially vacuum suction toward the peripheral portion from the central portion of the upper wafer W _U. Away from the upper wafer W _U is upper chuck 141, it is sequentially bonded toward the peripheral portion from the central portion and the wafer W _U and the wafer W _L. Then, the overall total and the wafer W _L of the wafer W _U are joined as shown in FIG. 17, the overlapped wafer W _T can be obtained.

As described above, according to the present embodiment, the upper imaging unit 161 and the lower imaging unit 171 capture the image of light from the light source (for example, the lower light source 175), and the upper imaging unit 161 and the lower imaging unit 171 Correct relative position information. If caused to turn off the light source, the light from the light source is not interfere with imaging of the upper wafer W _U and the lower wafer W _L, a stopper for stopping the driving unit and the light source to move the light source to the predetermined position is not required. Therefore, it is possible to vibration or deformation such as those of the driving unit and the stopper can be eliminated to improve the alignment accuracy between the upper wafer W _U and _the lower wafer W _L. Moreover, a sliding part can be reduced and a dust source can be reduced. The alignment accuracy can be further improved by causing each of the upper imaging unit 161 and the lower imaging unit 171 to capture images of light from the light source (for example, the lower light source 175) and the auxiliary light source (for example, the upper light source 165).

  Further, according to the present embodiment, the upper optical unit 160 includes the upper imaging unit 161 and the upper reflecting unit 164, the lower optical unit 170 includes the lower imaging unit 171 and the lower light source 175, and the lower imaging unit 171 is the upper reflecting unit. The light from the lower light source 175 reflected at 164 is imaged.

  Similarly, the upper optical unit 160 includes an upper imaging unit 161 and an upper light source 165, the lower optical unit 170 includes a lower imaging unit 171 and a lower reflecting unit 174, and the upper imaging unit 161 is reflected by the lower reflecting unit 174. The light from the light source 165 is imaged.

  Further, as shown in FIG. 7 and FIG. 8, the control device 5 causes the lower imaging unit 171 to capture the image of the light from the lower light source 175 reflected by the upper reflecting unit 164 and the light from the lower light source 175. The upper optical unit 160 and the lower optical unit 170 are relatively moved to a position where the upper imaging unit 161 captures an image. As shown in FIG. 7, the light from the lower light source 175 is condensed on the reflecting surface 164a of the upper reflecting portion 164, but the condensing position may be anywhere within the reflecting surface 164a. Misalignment is acceptable.

  Similarly, as illustrated in FIGS. 9 and 10, the control device 5 causes the upper imaging unit 161 to capture the image of the light from the upper light source 165 reflected by the lower reflection unit 174 and the light from the upper light source 165. The upper optical unit 160 and the lower optical unit 170 are relatively moved to the position at which the lower imaging unit 171 takes the image. As shown in FIG. 9, the light from the upper light source 165 is condensed on the reflecting surface 174a of the lower reflecting portion 174, but the condensing position may be anywhere within the reflecting surface 174a. Misalignment is acceptable.

In the present embodiment, the upper wafer _{W U} is the first substrate, the lower wafer _{W L} is the second substrate, the overlapped wafer _{W T} is the third substrate, the upper chuck 141 is in the first holding portion, the lower chuck 151 Is the second holding unit, the upper optical unit 160 is the first optical unit, the lower optical unit 170 is the second optical unit, the upper imaging unit 161 is the first imaging unit, and the lower imaging unit 171 is the second imaging unit. The upper reflecting portion 164 corresponds to the first reflecting portion, and the lower reflecting portion 174 corresponds to the second reflecting portion. However, in this specification, terms such as “first” and “second” do not limit the vertical relationship. For example, the upper chuck 141 may correspond to the second holding unit, and the lower chuck 151 may correspond to the first holding unit.

  FIG. 18 is a side view showing an upper optical unit and a lower optical unit according to a modification. FIG. 18 shows the positional relationship between the upper optical unit and the lower optical unit when the lower imaging unit and the upper imaging unit simultaneously capture an image of light from the lower light source.

  The upper optical unit 160A of the present modification includes an upper imaging unit 161A, an upper macro lens 162A, an upper micro lens 163A, an upper reflection unit 164A, an upper imaging unit side separation unit 166A, an upper micro lens side separation unit 167A, and the like. The upper reflecting portion 164A shown in FIG. 18 is arranged at the position of the upper light source 165 shown in FIGS. On the other hand, the lower optical unit 170A includes a lower imaging unit 171A, a lower macro lens 172A, a lower micro lens 173A, a lower light source 175A, a lower imaging unit side separation unit 176A, a lower micro lens side separation unit 177A, and the like.

  In the optical correction process of this modification, the lower chuck drive unit 152 is controlled to change the position of the lower optical unit 170A, and the light from the lower light source 175A is simultaneously captured by the upper imaging unit 161A and the lower imaging unit 171A. .

  Part of the light from the lower light source 175A is reflected by the lower microlens side separator 177A, passes through the lower microlens 173A and the upper microlens 163A, and reaches the upper microlens side separator 167A. The upper microlens side separation unit 167A separates the light from the lower light source 175A into light traveling toward the upper imaging unit 161A and light traveling toward the upper reflection unit 164A.

  A part of the light transmitted through the upper microlens side separation unit 167A is reflected by the upper imaging unit side separation unit 166A and captured by the upper imaging unit 161A. On the other hand, the light reflected by the upper microlens side separation unit 167A is reflected by the upper reflection unit 164A. A part of the light reflected by the upper reflection part 164 is reflected again by the upper microlens side separation part 167A, passes through the upper microlens 163A and the lower microlens 173A, passes through the lower microlens side separation part 177A, The light is reflected by the lower imaging unit side separation unit 176A and captured by the lower imaging unit 171A. At this time, the focal point of the lower microlens 173A and the focal point of the upper microlens 163A may be on the same horizontal plane.

  According to this modification, the light from the lower light source 175A is separated into light directed to the upper imaging unit 161A and light directed to the upper reflecting unit 164A by the upper microlens side separation unit 167A. Can be simultaneously captured by the upper imaging unit 161A and the lower imaging unit 171A. The positional relationship between the upper optical unit 160A and the lower optical unit 170A does not change between when the upper imaging unit 161A is imaging and when the lower imaging unit 171A is imaging. Therefore, it is possible to accurately correct the relative position information between the upper imaging unit 161A and the lower imaging unit 171A.

  Note that the position of the upper reflecting portion 164A and the position of the upper imaging portion 161A may be reversed, and light transmitted through the upper microlens side separating portion 167A is directed to the upper reflecting portion 164A and reflected by the upper microlens side separating portion 167A. The light may be directed toward the upper imaging unit 161A. Further, the position of the lower light source 175A and the position of the lower imaging unit 171A may be reversed. Furthermore, an upper light source may be provided at the position of the upper reflection unit 164A, and a lower reflection unit may be provided at the position of the lower light source 175A, and light from the upper light source is simultaneously captured by the upper imaging unit 161A and the lower imaging unit 171A. You may let them. In the present modification, the upper optical unit includes a reflection unit that reflects light from the lower light source 175A toward the lower imaging unit 171A, but the lower optical unit may include the reflection unit.

  As mentioned above, although embodiment, such as a joining apparatus, was described, although embodiment etc. were described, the present invention is not limited to the above-mentioned embodiment etc., and within the limits of the gist of the present invention indicated in a claim, Various modifications and improvements are possible.

  For example, in the above embodiment, the wafer corresponds to the substrate described in the claims, but the type of the substrate may be various, for example, a substrate for an FPD (flat panel display), a mask reticle for a photomask The substrate may be used.

The interface system 1, the wafer W _U, the overlapped wafer W _T formed by joining the W _L is heated at a predetermined temperature, the wafer W _U, it may be more firmly bonded to W _L.

DESCRIPTION OF SYMBOLS 1 Joining system 2 Carrying in / out station 3 Processing station 5 Control apparatus 30 Surface modification apparatus 40 Surface hydrophilization apparatus 41 Joining apparatus 61 Wafer transfer apparatus 140 Upper stage 141 Upper chuck 150 Lower stage 151 Lower chuck 152 Lower chuck drive part 160 Upper optical Unit 161 Upper imaging unit 164 Upper reflection unit 165 Upper light source 167A Upper microlens side separation unit 170 Lower optical unit 171 Lower imaging unit 174 Lower reflection unit 175 Lower light source W _U upper wafer W _L lower wafer W _T superposition wafer

Claims (13)

A bonding apparatus for bonding the first substrate and the second substrate with the bonding surface of the first substrate facing the bonding surface of the second substrate,
A first holding unit for holding the first substrate;
A second holding unit for holding the second substrate;
A first imaging unit that captures an image of the second substrate held by the second holding unit;
A second imaging unit that captures an image of the first substrate held by the first holding unit;
A driving unit that relatively moves the first holding unit and the second holding unit, and relatively moves the first imaging unit and the second imaging unit;
A light source that emits light to the first imaging unit and the second imaging unit;
A controller that controls the drive unit based on the image of the first substrate and the image of the second substrate to align the first substrate and the second substrate;
The control unit causes the first imaging unit and the second imaging unit to capture an image of light from the light source, and corrects relative positional information between the first imaging unit and the second imaging unit; Joining device. A first optical unit and a second optical unit that are relatively moved by the drive unit;
The first optical unit includes the first imaging unit, and a first reflecting unit that reflects light from the light source,
The second optical unit includes the second imaging unit and the light source,
The joining apparatus according to claim 1, wherein the second imaging unit captures an image of light from the light source reflected by the first reflecting unit. The control unit causes the first imaging unit to capture an image of light from the light source, and a position to cause the second imaging unit to capture an image of light from the light source reflected by the first reflecting unit. The bonding apparatus according to claim 2, wherein the first optical unit and the second optical unit are relatively moved.   3. The bonding apparatus according to claim 2, wherein the first optical unit includes a separation unit that separates light from the light source into light traveling toward the first imaging unit and light traveling toward the first reflection unit. The first optical unit includes an auxiliary light source,
The second optical unit includes a second reflecting unit that reflects light from the auxiliary light source,
The first imaging unit captures an image of light from the auxiliary light source reflected by the second reflecting unit,
5. The control unit according to claim 2, wherein the control unit causes each of the first imaging unit and the second imaging unit to capture images of light from the light source and the auxiliary light source, and corrects the position information. The joining apparatus according to item 1. A processing station comprising the bonding apparatus according to claim 1;
A loading / unloading station that delivers the first substrate, the second substrate, and a third substrate formed by bonding the first substrate and the second substrate to the processing station;
The processing station is
A surface modification device for modifying the bonding surface of the first substrate and the bonding surface of the second substrate;
A surface hydrophilizing device for hydrophilizing the joint surface modified by the surface modifying device;
A transport device that transports the first substrate and the second substrate to the surface modification device, the surface hydrophilization device, and the joining device in this order;
The bonding apparatus is a bonding system in which the bonding surfaces hydrophilized by the surface hydrophilization device face each other to bond the first substrate and the second substrate. Bonding for bonding the first substrate and the second substrate with the bonding surface of the first substrate held by the first holding unit facing the bonding surface of the second substrate held by the second holding unit A method,
An optical correction step of correcting relative positional information of the first imaging unit and the second imaging unit that are relatively moved in accordance with the relative movement of the first holding unit and the second holding unit;
The first imaging unit captures an image of the second substrate held by the second holding unit, and the second imaging unit captures an image of the first substrate held by the first holding unit. Substrate imaging process;
A substrate alignment step of aligning the first substrate and the second substrate based on the image of the first substrate and the image of the second substrate;
In the optical correction step, the position information is corrected by causing the first imaging unit and the second imaging unit to capture an image of light from a light source. A first optical unit and a second optical unit that are relatively moved with the relative movement of the first holding unit and the second holding unit are used,
The first optical unit includes the first imaging unit, and a first reflecting unit that reflects light from the light source,
The second optical unit includes the second imaging unit and the light source,
The joining method according to claim 7, wherein the second imaging unit captures an image of light from the light source reflected by the first reflecting unit.   The first imaging unit captures an image of light from the light source, and the second imaging unit captures the image of light from the light source reflected by the first reflecting unit. The joining method according to claim 8, wherein one optical unit and the second optical unit are relatively moved.   The bonding method according to claim 8, wherein the first optical unit includes a separation unit that separates light from the light source into light traveling toward the first imaging unit and light traveling toward the first reflection unit. The first optical unit includes an auxiliary light source,
The second optical unit includes a second reflecting unit that reflects light from the auxiliary light source,
The first imaging unit captures an image of light from the auxiliary light source reflected by the second reflecting unit,
11. The optical correction step corrects the position information by causing each of the first imaging unit and the second imaging unit to capture images of light from the light source and the auxiliary light source. The joining method according to any one of the above.   The program for making a computer perform the joining method in any one of Claims 7-11. An information storage medium storing the program according to claim 12.

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