JP5792831B2 - Bonding apparatus and bonding method - Google Patents

Description

  The present invention relates to a laminating apparatus and a laminating method for laminating two discs to produce a disc laminate, and more specifically, thinning a circular workpiece such as a semiconductor substrate by surface grinding / polishing. In doing so, the present invention relates to a laminating apparatus and a laminating method in which a circular support having substantially the same diameter is centered and angle-adjusted in advance with respect to the circular workpiece.

  In a semiconductor three-dimensional stacking process represented by a TSV (Through Silicon Via) process, a technique for thinning a circular workpiece such as a semiconductor substrate by surface grinding and polishing is indispensable. For example, thinning is required to reduce the thickness to 30 to 50 μm with respect to a silicon wafer having a diameter of 300 mm. As described above, the circular workpiece having an extremely thin thickness with respect to the planar dimension cannot maintain the planar shape alone due to internal stress and own weight with its own rigidity. Therefore, as described in Patent Document 1, a step of bonding the circular support to the non-processed surface side of the circular workpiece in advance through an adhesive is required before the surface grinding / polishing process.

  In this bonding step, first, a liquid adhesive is uniformly applied to the entire surface of the circular workpiece before processing the flakes or the bonding surface of the circular support. As the adhesive, a thermosetting resin or a UV curable resin is generally used, and it can be fixed by heat treatment after bonding and UV irradiation. In addition, the circular support is processed in advance precisely in flatness, and heat-resistant glass or silicon wafer having the same diameter as the circular workpiece and the same thickness as that of the circular workpiece before thinning is used. The bonding process is performed in a vacuum chamber in which a circular workpiece and a circular support are sandwiched between a stage on the lower side and a pressure disk on the upper side. Each of the stage and the pressure disk is processed with a high degree of flatness, and the parallelism is also precisely adjusted in the vacuum chamber. In addition, the diameter of the stage and the pressure disk is reduced with respect to the circular workpiece and the circular support having substantially the same diameter, so that the stage is not fouled by the sticking out of the adhesive that occurs at the outer edge during bonding. It has been devised. In other words, the diameter of the pressure disk has been empirically used as a dimension value that prevents the adhesive protruding from the outer edge from adhering or fouling.

  On the other hand, in the laminating step, the total thickness of the laminated body composed of a circular support, an adhesive layer and a circular workpiece is approximately 10% of the thickness of the circular workpiece after laminating. It is required to suppress in-plane variation.

  For this reason, as described above, the stage and the pressure disc are processed with high precision and the flatness is adjusted and the parallelism is adjusted. A mechanism has been proposed in which bonding is performed by actively changing the planar shape of the pressure disk while monitoring the thickness and load distribution (see, for example, Patent Document 2).

Japanese Patent Laying-Open No. 2005-159155 (see paragraphs 0015 and 0016 and FIG. 2) Japanese Patent Laying-Open No. 2004-268113 (see paragraphs 0033 to 0050)

  However, in order to flatten the in-plane thickness distribution of the adhesive layer after bonding and before solidifying the adhesive, it is necessary to apply a load of 1000 kgf class on a circular workpiece having a plane size of 300 mm in diameter. In addition, it is inevitable to increase the rigidity of the members that support them, that is, to increase the length and height of the device. In addition, the cost of sensor equipment that actively monitors the plane state with high accuracy and the equipment that feeds back and reflects the output are complicated to control, and high responsiveness cannot be obtained. In the required semiconductor manufacturing apparatus, many problems that do not meet this requirement are exposed.

  Further, the outer edge portion of the circular workpiece in the pressurizing step is a free end with respect to the flow characteristics of the adhesive layer, and the boundary condition in the radial direction is different from the inner side. For this reason, the volume reduction between the circular workpiece and the circular support caused by the protrusion to the edge of the adhesive layer directly reduces the local thickness at the same site. It is clear that the radial range of this thickness reduction extends up to 10 mm inside from the outer peripheral edge and exhibits a thickness drop of −8 μm to −14 μm compared to the center.

  The inventor of the present application scrutinized the thickness profile in the radial direction of the laminated body after bonding, and ascertained that the higher-order concavo-convex shape mode (waving) was found in the profile, and the concavo-convex shape mode was a pressurized circle. It was confirmed that the diameter of the plate was changed by varying it, and the present invention was made.

  That is, the present invention aims at optimizing the uneven shape mode found in the radial thickness profile of the laminated body after bonding by adjusting the diameter dimension of the pressure disk, and thereby by an inexpensive apparatus configuration. It aims at improving the in-plane variation of the total thickness of the laminated body after bonding.

  In the laminating apparatus of the present invention, the first disk and the second disk are pre-centered, and the adhesive is uniformly applied to the upper surface of the first disk or the lower surface of the second disk. Then, by pressing the first disk and the second disk in the vertical direction, a disk laminate in which the second disk is bonded onto the first disk via an adhesive layer is manufactured. To do.

  Such a bonding apparatus has, as a specific configuration, a processing chamber having airtightness, a stage disposed in the processing chamber and supporting the first disc, and facing above the stage in the processing chamber. A pressure disk that is disposed and centered with respect to the first disk and the second disk, a lifting mechanism that supports the pressure disk so as to be movable up and down, and the second disk. A holding mechanism that is detachably held above the stage and below the pressure disk. In the laminating apparatus of the present invention, in such a configuration, the diameter dimension of the pressure disk is smaller than the diameter dimension of the second disk, and the thickness profile in the radial direction of the disk stack is Are set to dimensions that optimize the uneven shape mode.

  According to the structure of this bonding apparatus, when the pressurizing disk is lowered by the elevating mechanism in the processing chamber and the second disk is detached from the holding mechanism, the upper surface of the second disk is A disk laminate in which the pressure disk is pressed with an equal force on the stage, and the upper surface of the first disk and the lower surface of the second disk are bonded via an adhesive layer. Produced. The first disk, the second disk, and the pressure disk are pre-centered, and the diameter dimension of the pressure disk can be seen in the radial thickness profile of the disk stack. The dimensions are set to optimize the uneven shape mode. For this reason, the in-plane dispersion | variation in the total thickness of the disk laminated body after bonding is improved.

  As an example of a specific configuration, the holding mechanism includes one movable pin that comes into contact with one place on the side surface of the second disc, and a plurality of stationary pins that comes into contact with a plurality of places on the side surface of the second disc. A moving mechanism for reciprocally moving the movable pin in the radial direction of the second disk.

  According to the structure of this holding mechanism, the movable pin is pressed against the side surface of the second disc by moving the movable pin in the forward direction and moving the movable pin in the direction approaching the center in the radial direction of the second disc, The side surface of the second disk is gripped by the movable pin and the stationary pin. Conversely, by moving the moving mechanism in the backward direction to move the movable pin away from the center of the second disk, the movable pin is separated from the side surface of the second disk, and the side surface of the second disk is gripped. Is released and the second disk is removed.

  If the movable pin is engaged with an angle adjusting notch provided at one place on the side surface of the second disk, the angular position of the second disk is determined simultaneously with the holding of the second disk.

  As another example of the specific configuration, the holding mechanism may include a suction mechanism that adsorbs the upper surface of the second disk to the pressure surface of the pressure disk. According to this, by operating the suction mechanism, the suction adsorption force acts on the second disk, and the upper surface of the second disk is adsorbed on the pressure surface of the pressure disk. Conversely, if the suction mechanism is stopped, the second disk is detached from the pressure disk. In this configuration of the holding mechanism, since the second disk is held by the pressure disk itself, another holding member is unnecessary, and the holding mechanism can be simplified.

  When the bonding apparatus has a pressure reducing mechanism for reducing the pressure inside the processing chamber, the vacuum is achieved so that the degree of vacuum achieved by the suction mechanism is smaller than the degree of vacuum in the vacuum chamber achieved by the pressure reducing mechanism. It is necessary to provide a pressure adjusting mechanism for adjusting the pressure in the chamber. Thereby, it is possible to prevent the holding force by the suction mechanism from being weakened before the pressurizing process and the second disc is dropped.

  In addition, when equipped with an attachment / detachment mechanism that positions the center of the pressure disk and detachably supports it on the lifting mechanism, the pressure disk can be easily replaced, and it is easy to change lots of disk stacks. It becomes possible to do.

  Further, in the bonding method of the present invention, the second disk with center alignment is held oppositely above the first disk that is supported on the stage and the adhesive is uniformly applied to the upper surface. The first disk and the second disk are bonded together by pressing the upper surface of the second disk with an equal force with a pressure disk centered on the first disk and the second disk. Thus, a disk laminate is produced. In the laminating method of the present invention, a pressure disk having an optimized diameter dimension of the uneven shape mode found in the thickness profile of the circular laminated body in the radial direction is used in the pressure treatment step.

  Bonding needs to be performed under vacuum so that air bubbles are not caught in the adhesive layer.

  When the diameter dimension of the second disk is set larger than the diameter dimension of the first disk, the adhesive layer applied to the upper surface of the first disk is applied to the first disk during the pressure treatment. Even if it protrudes to the outside, it flows to the outer edge of the lower surface of the second disk that is slightly larger than the first disk and stays there, so that the adhesive adheres to the side surface of the first disk. There is nothing. Therefore, it is possible to prevent the diameter of the first disc after bonding from becoming uneven in the circumferential direction.

  The pressure disk having the optimum diameter is different for each lot of the disk stack. Therefore, if the optimum diameter dimension of the pressurizing disk is managed for each lot, when the lot is changed, it can be easily coped with only by exchanging with the corresponding pressurizing disk.

  For example, a silicon wafer is used for the first disk, and a glass support is used for the second disk. As an example of the adhesive, a photocurable resin or a thermosetting resin is used.

  According to the present invention, it is possible to improve the in-plane variation of the total thickness of the laminated body after bonding with an inexpensive apparatus configuration.

It is a side view which shows schematic structure of the bonding apparatus which concerns on the 1st Embodiment of this invention, and has shown the state before the pressurization process with respect to a 1st disc and a 2nd disc. It is a side view which shows schematic structure of a bonding apparatus same as the above, and has shown the state in the pressurization process with respect to a 1st disc and a 2nd disc. It is a top view explaining the holding mechanism of a 2nd disk. FIG. 4A is a side view for explaining the moving mechanism of the movable pin, and shows a state in which the movable pin is pressed against the side surface of the second disk to hold the second disk. FIG. 4B is a side view for explaining the moving mechanism of the movable pin, and shows a state where the movable pin is separated from the side surface of the second disk and the holding of the second disk is released. It is a figure which shows the thickness profile of the radial direction of the disk laminated body after bonding. It is a side view which shows schematic structure of the bonding apparatus which concerns on the 2nd Embodiment of this invention.

  Hereinafter, a first embodiment embodying the present invention will be described with reference to FIGS.

  FIG. 1 is a front view showing a schematic configuration of a bonding apparatus according to the first embodiment of the present invention. In this laminating apparatus, a disc stack is produced by laminating two kinds of first disc W1 and second disc W2 that are oppositely arranged with an adhesive uniformly applied to either one in advance. The first disk is, for example, a semiconductor circular workpiece such as a silicon wafer, and the second disk is, for example, a glass circular support.

  As shown in FIG. 1, the bonding apparatus 10 includes a chamber (processing chamber) 20, a decompression mechanism 30, an opening / closing mechanism 40, a stage 50, a pressurizing disk 60, an elevating mechanism 70, and a holding mechanism 80 as main components. Is provided.

  The laminating apparatus 10 includes a base plate 11 and a gate-shaped support frame 12 fixed to the base plate 11. The base plate 11 and the support frame 12 are formed of a material having sufficiently high rigidity. A chamber 20 as a processing chamber is provided inside the support frame 12. The chamber 20 is divided into upper and lower parts, and is composed of an upper container 20A and a lower container 20B. An O-ring 21 is provided at the opening of the chamber 20, that is, at a place where the upper container 20 </ b> A and the lower container 20 </ b> B come into contact with each other to keep the inside of the chamber 20 airtight.

  The lower container 20B is supported by the base plate 11. The upper container 20 </ b> A is suspended and supported by the support frame 12, and can be moved up and down (moved up and down) by the opening / closing mechanism 40.

  The opening / closing mechanism 40 includes an actuator 41, an elevating plate 42, and a column 43. The actuator 41 has a piston 411 and a cylinder 412. The piston 411 is a non-moving portion of the actuator 41 and is erected vertically at the center of the upper surface of the ceiling wall of the support frame 12. The cylinder 412 is a movable part of the actuator 41 and is configured to be movable up and down along the piston 411. As an example, the actuator 41 is driven by solenoid, hydraulic pressure, pneumatic pressure, or the like as power, and is configured to be controllable by an electrical signal using a control mechanism (not shown). The elevating plate 42 is fixed to the cylinder 412 of the actuator 41 and can move up and down together with the cylinder 412 while keeping the level. The piston 411 is inserted through the center of the lifting plate 42.

  At the outer edge of the lower surface of the elevating plate 42, the upper ends of a plurality of columns 43 that hang vertically are fixed. The support 43 is penetrated through the ceiling wall of the support frame 12, and the lower end thereof is fixed to the upper surface of the upper container 20A. As a result, the upper container 20 </ b> A is suspended and supported by the elevating plate 42 via the column 43.

  In the configuration of the opening / closing mechanism 40, when the actuator 41 is driven, the upper container 20A is moved up and down relative to the lower container 20B in conjunction with the vertical movement of the cylinder 412. Thereby, the opening / closing operation | movement of the chamber 20 is performed. FIG. 1 shows a state in which the chamber 20 is opened, and FIG. 2 shows a state in which the chamber 20 is closed.

  The decompression mechanism 30 includes a vacuum line 31, a vent line 32, a vacuum pump 33, a vacuum valve 34 and a vent valve 35. The vacuum line 31 is formed by piping made of a vacuum material, and the intake side is attached through the lower container 20B. As a result, the vacuum line 31 communicates with the chamber 20. The vacuum line 31 is provided with a vacuum pump 33 and a vacuum valve 34. The vent line 32 is branched from the vacuum line 31 on the upstream side of the vacuum valve 34, and is connected to a pressure-resistant container containing an inert gas (for example, nitrogen). The vent line 32 is formed by piping. A vent valve 35 is provided in the vent line 32.

  With the configuration of the pressure reducing mechanism 30 described above, when the vacuum valve 34 is opened with the chamber 20 closed as shown in FIG. 2 and the vacuum pump 33 is driven, the air in the chamber 20 is exhausted through the vacuum line 31. The Thereby, the inside of the chamber 20 is depressurized and a high vacuum is obtained. The vent valve 35 is opened when an inert gas such as nitrogen is leaked into the chamber 20 through the vent line 32 to return the pressure in the chamber 20 to normal pressure. The pressure in the chamber 20 is monitored by a vacuum gauge 17 attached to the outside of the upper container 20A.

  In the chamber 20, a stage 50 as a support plate for supporting the first disc W1 and a pressurizing disc 60 for pressurizing the second disc W2 are arranged to face each other. The stage 50 has a mechanism for attracting and holding the first disk W1 by applying at least one of a suction attracting force or an electrostatic attracting force.

  The pressurizing disk 60 is supported by an elevating mechanism 70 provided in the upper container 20A so as to be movable up and down. The lifting mechanism 70 includes an actuator 71, a mounting base 72, a support shaft 73, and a disk magnet 74. The pressure disk 60 is mounted and adjusted with respect to the stage 50 with a parallelism of 4 μm or less.

  The actuator 71 has a piston 711 and a cylinder 712. The cylinder 712 is a non-moving portion of the actuator 71, and its axial direction is oriented vertically, and is attached to a mounting base 72 fixed to the ceiling wall of the upper container 20A. The piston 711 is a movable part of the actuator 71, and is configured to be movable in the axial direction of the cylinder 712, that is, vertically movable, through the mounting base 72. For example, the actuator 71 is driven by a solenoid, hydraulic pressure, pneumatic pressure, or the like as power, and is configured to be controllable by an electrical signal using a control mechanism (not shown).

  The upper end of the support shaft 73 is coaxially fixed to the lower end of the piston 711 of the actuator 71. The support shaft 73 is formed in a columnar shape, and is inserted through a through hole provided at the center of the ceiling wall of the upper container 20A. A shaft seal 14 is provided in the through hole of the upper container 20A, and the shaft seal 14 seals between the upper container 20A and the support shaft 73. A disc magnet 74 is horizontally attached to the lower end of the support shaft 73. The disc magnet 74 is attached in a state of being precisely aligned with the axes of the piston 711 and the support shaft 73, the center of which is set coaxially. The pressure disk 60 is made of a magnetic material (for example, an alloy containing a magnetic material), and can be attracted and held by applying the magnetic attraction force of the disk magnet 74.

  The diameter of the pressure disk 60 and the smoothness of the pressure surface (lower surface) are processed with extremely high accuracy. A plurality of positioning protrusions (not shown) are formed on the upper surface of the pressure disk 60 in the center and in the circumferential direction around the center. On the other hand, a plurality of positioning holes are formed at locations corresponding to the positioning protrusions on the lower surface of the disc magnet 74. Therefore, when the pressing disk 60 is attracted and held by the disk magnet 74 so that the positioning protrusions on the upper surface of the pressing disk 60 are fitted in the corresponding positioning holes on the lower surface of the disk magnet 74, The plate 60 is mounted in a state in which displacement is prevented and the center thereof is aligned with the axes of the piston 711 and the support shaft 73.

  The disk magnet 74 and its positioning hole, and the positioning protrusion of the pressure disk 60 are an example of an attachment / detachment mechanism that allows the pressure disk 60 to be attached and detached. In this attachment / detachment mechanism using magnetic attraction, fixing parts such as screws are unnecessary, and attachment / detachment work can be performed very easily with one touch. In particular, the pressurization method according to the present invention, in which the pressurization disk 60 needs to be replaced for each lot of the disk stacks, can be easily replaced, and thus is a very useful attachment / detachment mechanism.

  In the configuration of the lifting mechanism 70 described above, when the actuator 71 is driven by the control mechanism, the pressure disk 60 is moved up and down relative to the stage 50 in conjunction with the vertical movement of the piston 711. Therefore, as shown in FIG. 2, by lowering the pressure disk 60 with the chamber 20 closed, an object to be pressed sandwiched between the pressure disk 60 and the stage 50, that is, A vertical pressure is applied to the first disc W1 and the second disc W2.

  The stage 50 is supported by the lower container 20B. A plurality of lift pins 13 are passed through the stage 50 from below. The plurality of lift pins 13 are erected vertically on the support member 16. The support member 16 can be moved up and down by an elevating mechanism 90, and thereby, the tip end portion of the lift pin 13 can be projected and retracted from the support surface (upper surface) of the stage 50. The structure of the raising / lowering mechanism 90 is the same as that of the raising / lowering mechanism 70 of the pressurization disc 60 mentioned above.

  The first disk W1 is transported above the stage 50 by a transport device (not shown) provided with a robot arm in a state in which the center and angle are adjusted in advance using an alignment device (not shown). Is supported by lift pins 13 projecting from the top. When the lift pin 13 is lowered in this state, the first disc W1 is supported at a fixed position on the support surface of the stage 50.

  The second disk W2 is detachably held above the stage 50 and below the pressure disk 60 by the holding mechanism 80. In the present embodiment, the holding mechanism 80 is configured to be able to grip the side surface of the second disc W2. The holding mechanism 80 includes a movable pin 81, a stationary pin 82, and a moving mechanism (device) 83.

  FIG. 3 is a plan view illustrating the holding mechanism 80. 4A and 4B are side views illustrating the moving mechanism 83 of the movable pin 81. FIG. Details of the holding mechanism 80 will be described with reference to FIGS. 3, 4 (A), and 4 (B). As shown in FIG. 3, the movable pin 81 is engaged with an angle adjusting notch N formed at one place on the side surface of the second disk W2, and the two stationary pins 82 are on the side surface of the second disk W2. Are abutted at two locations. One movable pin 81 and two stationary pins 82 are provided in a planar arrangement in which the circumference of the second disk W2 is equally divided into three at a central angle of 120 °. The movable pin and the stationary pin 82 are formed in a cylindrical shape as an example. As shown in FIG. 1, the immovable pin 82 is fixed to the inner surface of the ceiling wall of the upper container 20A with the axial direction vertical.

  The moving mechanism 83 is configured to be able to reciprocate the movable pin 81 in the radial direction of the second disk W2. 4A and 4B, the moving mechanism 83 includes a stepping motor 831, a ball screw nut 832, a ball screw 833, a stem 834, a support shaft 835, a stopper 836, a flange 837, a compression coil spring 838, and the like. A bearing 839 is provided.

  The stepping motor 831 is fixed to the outer surface of the ceiling wall of the upper container 20A with its drive shaft oriented in the direction away from the center in the radial direction of the second disc W2. The stepping motor 831 is configured to be able to rotate the drive shaft in both forward and reverse directions by pulse driving, and the driving force is transmitted to the ball screw nut 832 to rotate the ball screw nut 832 by a predetermined amount in the forward direction or the reverse direction. The rotational motion of the ball screw nut 832 is converted into the linear motion of the ball screw 833. The tip of the ball screw 833 is attached to the top of a vertically extending stem 834. A base end of a support shaft 835 extending in parallel with the ball screw 833 is attached to the lower portion of the stem 834.

  The support shaft 835 is inserted through the through hole in the side wall of the upper container 20A. A shaft seal 14 is provided in the through hole of the upper container 20A, and the shaft seal 14 seals between the upper container 20A and the support shaft 835. A flange 837 is formed at a portion located inside the upper container 20 </ b> A in the axial direction of the support shaft 835. The distal end portion of the support shaft 835 is inserted into the through hole of the movable pin 81. A bearing 839 is provided in the through hole of the movable pin 81, and the bearing 839 enables sliding along the support shaft 835 of the movable pin 81.

  A compression coil spring 838 is provided in a portion between the flange 837 and the movable pin 81 in the axial direction of the support shaft 835, and the movable pin 81 is urged toward the distal end side of the support shaft 835 by the compression coil spring 838. A stopper 836 is attached to the tip of the support shaft 835, and the movable pin 81 is prevented from coming off the support shaft 835 by the stopper 836.

  With such a configuration of the moving mechanism 83, when the stepping motor 831 is driven to rotate in the forward direction, the support shaft 835 approaches the center in the radial direction of the second disk W2 as indicated by the arrow in FIG. Moving. As a result, the movable pin 81 urged by the compression coil spring 838 is pressed against the side surface of the second disk W2, and the second disk W2 is held at three positions on the side surface by the movable pin 81 and the two stationary pins 82. Is done. As shown in FIG. 3, it is assumed that the mounting position of the stationary pin 82 is set so that the center of the second disk W <b> 2 is aligned with the center of the pressure disk 60. At this time, if the movable pin 81 is engaged with a notch N provided on one side of the second disk W2, the angle of the second disk W2 can be adjusted.

  On the other hand, when the stepping motor 831 is driven to rotate in the reverse direction, the support shaft 835 moves away from the center in the radial direction of the second disk W2, as indicated by the arrow in FIG. Thereby, the movable pin 81 is separated from the side surface of the second disk W2, and the second disk W2 is detached. When the second disc W2 is pressed against the first disc W1 on the stage 50 by the pressurizing disc 60, the second disc W2 is detached as shown in FIG. 4B. Alternatively, pressurization may be performed in a state where the second disk W2 is held by the pins as shown in FIG. In the latter case, it is effective to prevent the displacement of the second disk W2 with pressure. The gripping force of the second disk W2 can be adjusted by the spring constant of the compression coil spring 838.

  The usage method of the bonding apparatus 10 comprised as mentioned above is demonstrated. First, as a preparation stage, the holding mechanism 80 holds the second disk W2 with the chamber 20 opened, and the first disk W1 is placed on the stage 50 using the second disk W2 as a reference for alignment. To support. As a result, the first disk W1 and the second disk W2 are disposed in the chamber 20 so as to face each other in the vertical direction. Note that an adhesive is uniformly applied to the upper surface of the first disk W1 with a predetermined film thickness. After the upper container 20A is lowered by the opening / closing mechanism 40 and the chamber 20 is closed, the decompression mechanism 30 is operated to keep the inside of the chamber 20 at a high vacuum.

  In the pressurizing process, the pressurizing disc 60 is lowered by the elevating mechanism 70 and the second disc W2 is detached from the holding mechanism 80. As a result, the upper surface of the second disc W2 is pressed with a uniform force on the stage 50 by the pressurizing disc 60, and the upper surface of the first disc W1 and the lower surface of the second disc W2 form the adhesive layer. Thus, a disk laminate bonded together is produced. The first disc W1, the second disc W2, and the pressure disc 60 are centered in advance. Further, as will be described later, the diameter dimension of the pressure disk 60 is set to a dimension that optimizes the uneven shape mode found in the radial thickness profile of the disk stack. For this reason, the in-plane dispersion | variation in the total thickness of the disk laminated body after bonding is improved.

  For example, a thermosetting resin or a UV curable resin is used as the adhesive. The disk laminate after the bonding is taken out from the bonding apparatus 10, and the adhesive layer is solidified by heating or UV irradiation in the next step to obtain a product.

  In the laminating apparatus 10 of the present invention, by performing pressure treatment using a pressure disk having a diameter dimension in which the uneven shape mode is optimized, the disk after bonding with a simple apparatus configuration. In-plane variation of the total thickness of the laminate can be suppressed. Hereinafter, the procedure for setting the dimensions of the pressure disk will be described by way of example.

  Prepare five identical silicon wafers (diameter 300 mm, thickness 775 μm) as the first disk W1 and five identical glass disks (diameter 301 mm, thickness 675 μm) as the second disk W2. The same type of adhesive is uniformly applied to the non-processed surface with the same film thickness (50 μm). Then, five types (296 mm, 290 mm, 285 mm, 280 mm, and 270 mm) of pressure disks 60 having different diameter dimensions are prepared, and a silicon wafer is bonded to the silicon wafer by using the bonding apparatus 10 to which the pressure disks 60 are attached. A glass disk was bonded. The pressure at the time of pressurization was set to be the same for any pressurization disc 60. The thickness profile in the radial direction of the obtained disk laminate is shown in FIG. The diameter of the stage is 296 mm.

  As shown in FIG. 5, it was found that any profile exhibits a higher-order concavo-convex shape mode that is line-symmetric with respect to the center line. Table 1 summarizes the analysis of the uneven shape mode.

  As shown in FIG. 5 and Table 1, the diameter range of the pressure disc examined in the experiment is smaller than the diameter (300 mm) of the silicon wafer that is the workpiece, and the thickness is measured for all five diameter dimensions. The number of maximal points of the concavo-convex mode found in the profile is three (one at the center and two on the left and right), and there is no change and is common. On the other hand, the number of minimum points is two at 296 mm, 290 mm, and 285 mm, and is increased by two to four at 280 mm and 270 mm.

  In detail, when the diameter of the pressure disk is 296 mm and 290 mm, the singular point (outermost singular point) farthest from the center in the radial direction becomes the maximum point, and as a result of decreasing monotonically outside it, The outer peripheral edge has the minimum thickness. As mentioned at the beginning, by using a pressure disk with a large diameter, the pressure applied to the outer edge of the silicon wafer, which is the free end, causes the adhesive at the same area to stick out to the edge, resulting in local contact at that area. This is because a drop in thickness occurs.

  When the diameter of the pressure disk is reduced to 285 mm, the profile itself is not much different from that at 296 mm and 290 mm, but an inflection point appears on the outer side of the maximum point farthest from the center in the radial direction, The decrease in thickness outside the inflection point is suppressed.

  When the diameter is further reduced and the pressure disk diameter is 280 mm and 270 mm, a minimum point appears on the outer side of the maximum point farthest from the center in the radial direction, and the point giving the minimum thickness is from the outer peripheral edge in the radial direction. Shift inward. By using a pressure disk with a small diameter, the boundary condition of the outer edge of the silicon wafer is changed, and the pressure acting on this outer edge is reduced, so that the protrusion of the adhesive is reduced, and the uneven shape of the same part The mode turns from falling to rising.

  In this way, the diameter dimension of the intermediate pressure disk in which the singular point (outermost singular point) farthest from the center in the radial direction changes from the local maximum point to the local minimum point is 285 mm. It can be seen that the thickness profile uneven shape mode is greatly changed. In this example, the in-plane variation of the total thickness of the laminated discs after bonding is minimized by the diameter corresponding to this turning point.

  However, the diameter dimension of the pressure disk that minimizes the in-plane variation of the total thickness of the disk stack is not necessarily the diameter dimension corresponding to the turning point of the profile, the diameter dimension and thickness of the silicon wafer and the glass plate to be used, Furthermore, the optimum diameter dimension varies depending on the type of adhesive and the film thickness (that is, the lot of disk laminates). For this reason, the optimal diameter dimension of the pressure disk is tested with multiple pressure disks with different diameter dimensions for each lot of disk stacks, and the changes in the uneven shape mode of the thickness profile are tracked as described above. However, it must be determined experimentally. However, once the optimum diameter dimension has been determined, the pressure disk required to produce the lot with the same apparatus is uniquely determined. Therefore, if the optimum diameter dimension is managed in association with various lots of the disk stack, even if the lot changes, it is only necessary to replace the pressure disk with the corresponding diameter dimension and control the apparatus. Since it is not necessary to change the parameters, the present invention is very simple and useful.

  FIG. 6 is a front view showing a schematic configuration of a bonding apparatus according to the second embodiment of the present invention. In the second embodiment, the holding mechanism that holds the second disk W2 in the previous stage of the pressurizing process causes suction suction force to act on the second disk W2 to suck and hold the pressure disk 60. A mechanism 180 is provided.

  The suction mechanism 180 includes a vacuum line 181, a vacuum pump 182, and a vacuum valve 183. The suction side of the vacuum line 181 is passed through the inner side of the support shaft 73 of the lifting mechanism 70 in the axial direction, reaches the pressure surface (lower surface) of the pressure disk 60, and is opened as an air intake hole. The degree of vacuum of the vacuum line 181 is monitored by a vacuum gauge 19. The suction mechanism 180 has the same configuration as the decompression mechanism 30 that achieves a vacuum in the chamber 20.

  If the pressure in the chamber 20 is normal pressure, the second disk W2 can be adsorbed and held by the above configuration. However, since the pressure environment in the chamber 20 is set to a high vacuum in the pressurization process, In the configuration, when the degree of vacuum in the chamber 20 increases and becomes higher than the degree of vacuum in the vacuum line 181, the holding force is weakened, and the second disk W2 may fall before the pressure disk 60 is lowered. . In order to prevent such a situation, a pressure adjusting mechanism 100 is additionally provided.

  The pressure adjustment mechanism 100 is for maintaining the degree of vacuum of the vacuum line 181 of the suction mechanism 180 higher than the degree of vacuum in the chamber 20, and includes a nitrogen gas introduction line 101, a mass flow controller (MFC) 102, and a slot valve 103. Is provided. The nitrogen gas introduction line 101 is formed by piping, and the gas introduction side is attached through the upper container 20A. Thereby, the nitrogen gas introduction line communicates with the inside of the chamber 20. The slot valve 103 is a valve configured to be capable of dynamically adjusting an opening degree additionally provided in the vacuum line 31 of the pressure reducing mechanism 30.

  By operating the pressure reducing mechanism 30 while dynamically adjusting the opening of the slot valve 103 while introducing nitrogen gas into the chamber 20 using the mass flow controller 102 in the configuration of the pressure adjusting mechanism 100, The degree of vacuum in the chamber 20 can be maintained at a predetermined pressure. Thereby, the degree of vacuum of the vacuum line 181 of the suction mechanism 180 is maintained higher than the degree of vacuum in the chamber 20, and the second disk W2 can be adsorbed.

  In order to release the second disc W2 adsorbed and held by the pressurizing disc 60 in the pressurizing process, the vacuum valve 183 provided in the vacuum line 181 is closed and the suction force of the vacuum pump 182 is forced. Cut off.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

DESCRIPTION OF SYMBOLS 10 ... Laminating apparatus 20 ... Chamber 30 ... Depressurization mechanism 40 ... Opening / closing mechanism 50 ... Stage 60 ... Pressing disc 70 ... Elevating mechanism 74 ... Disc magnet (detachment mechanism)
80 ... holding mechanism 83 ... moving mechanism 100 ... pressure adjusting mechanism 180 ... suction mechanism W1 ... first disc W2 ... second disc

Claims (15)

The first disk and the second disk are centered in advance, and an adhesive is uniformly applied to the upper surface of the first disk or the lower surface of the second disk, and the first disk and the second disk A laminating apparatus for producing a disk laminate in which the second disk is bonded onto the first disk via an adhesive layer by pressurizing the second disk in the vertical direction,
An airtight process chamber;
A stage disposed in the processing chamber and supporting the first disc;
A pressure disk disposed opposite to the stage in the processing chamber and centered with respect to the first disk and the second disk;
An elevating mechanism for supporting the pressurizing disk so as to be elevable;
A holding mechanism for releasably holding the second disk above the stage and below the pressure disk;
Have
The diameter dimension of the pressure disk is smaller than the diameter dimension of the second disk, and is set to a dimension that optimizes the uneven shape mode seen in the radial thickness profile of the disk stack. Bonding device.   The holding mechanism includes one movable pin that contacts one place on the side surface of the second disk, a plurality of fixed pins that contact a plurality of places on the side surface of the second disk, and the second pin that moves the movable pin to the second position. The bonding apparatus according to claim 1, further comprising: a moving mechanism that reciprocates in a radial direction of the disk.   The bonding apparatus according to claim 2, wherein the movable pin is engaged with an angle adjusting notch provided at one place on a side surface of the second disk.   The bonding apparatus according to claim 1, wherein the holding mechanism includes a suction mechanism that attracts the upper surface of the second disk to the pressure disk.   A pressure reducing mechanism for depressurizing the processing chamber, and the pressure in the vacuum chamber is set so that the degree of vacuum achieved by the suction mechanism is smaller than the degree of vacuum in the vacuum chamber achieved by the pressure reducing mechanism. The bonding apparatus according to claim 4, further comprising a pressure adjusting mechanism for adjusting.   The bonding apparatus according to claim 1, wherein the elevating mechanism includes an attachment / detachment mechanism that positions the center of the pressure disk and supports the attachment / detachment detachably. A centered second disk is held oppositely above a first disk supported on a stage and coated with an adhesive uniformly on the upper surface, and the first disk and the second disk Bonding is performed by pressing the upper surface of the second disk with an equal force with a pressure disk centered with the first disk and the second disk to bond the first disk and the second disk. In the method
The diameter dimension of the pressure disk is smaller than the diameter dimension of the second disk, and is set to a dimension that optimizes the uneven shape mode seen in the radial thickness profile of the disk stack. The pasting method.   The laminating method according to claim 7, wherein the pressure treatment with the pressure disk is performed under high vacuum.   The bonding method according to claim 7, wherein a diameter dimension of the second disk is larger than a diameter dimension of the first disk.   The bonding method according to claim 8, wherein a diameter dimension of the second disk is larger than a diameter dimension of the first disk.   The laminating method according to claim 8, wherein, for each lot of the disk laminate, the pressure disk having a corresponding diameter is exchanged.   The laminating method according to claim 9, wherein, for each lot of the disk laminate, the pressure disk having a corresponding diameter is exchanged.   The laminating method according to claim 10, wherein each lot of the disk laminate is replaced with the pressure disk having a corresponding diameter dimension.   The bonding method according to claim 11, wherein the first disk is a silicon wafer and the second disk is a glass support.   The bonding method according to claim 14, wherein the adhesive is a photocurable resin or a thermosetting resin.

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