Bonding device

Abstract

In this bonding device, a suction surface for holding a first workpiece via a sheet by sucking the back surface of the sheet and a recessed surface recessed from the suction surface around the periphery of the suction surface are formed on a tip end surface of a pressing part. A peripheral holding part is a portion that holds a peripheral region of a region of the sheet to which the first workpiece is attached. The peripheral holding part has a configuration in an annular shape, and has an annular suction surface that sucks and holds the entire peripheral region. The pressing part and the peripheral holding part have a sealing structure that seals space between the outer circumferential edge of the recessed surface and the inner circumferential surface of the peripheral holding part. Thus, when the sheet is sucked onto the suction surface of the pressing part and the suction surface of the peripheral holding part, a sealed space is formed between the suction surfaces. The bonding device reduces the internal pressure of the sealed space when the first workpiece is pressed.

Description

Bonding equipment

[0001] The present invention relates to a bonding technique for chips and substrates.

[0002] Patent Document 1 discloses a technique for bonding a chip (such as an LSI or IC) attached to the surface of an elastically deformable sheet (such as dicing tape) by holding the chip via the sheet and pressing the chip against the surface of a substrate (such as a wafer). This bonding technique requires that the sheet be peeled off from the chip after the chip is pressed against the surface of the substrate.

[0003] Japanese Patent Application Laid-Open No. 2018-160687

[0004] On the other hand, with the conventional bonding technology disclosed in Patent Document 1, there was a case where the sheet could not be smoothly peeled off from the chip after pressing the chip against the surface of the substrate. When such a case occurred, when attempting to separate the chip from the sheet, the remaining adhesive force between them could have an adverse effect on the chip (such as the bonded chip being peeled off from the surface of the substrate or being damaged). Such adverse effects on the chip could lead to reduced productivity and a decrease in yield.

[0005] Therefore, the object of the present invention is to facilitate the peeling of the sheet from the workpiece after joining in a joining technology for a workpiece attached to the surface of a sheet, thereby improving the peeling speed while suppressing adverse effects on the workpiece.

[0006] The joining device according to the present invention has the following configuration. The joining device includes a sheet holding unit, a pressing unit, and a peripheral holding unit. The sheet holding unit is a unit that holds the peripheral edge of the sheet to which the first workpiece is attached. The pressing unit is a unit that has an adsorption surface formed on its tip surface that holds the first workpiece via the sheet by adsorbing the back surface of the sheet, and it is possible to press the first workpiece against the surface of the second workpiece by bringing the adsorption surface close to the surface of the second workpiece. The peripheral holding unit is a unit that holds the peripheral area of ​​the sheet around the area to which the first workpiece is attached when pressing the first workpiece.

[0007] Furthermore, the joining device further includes the following configuration (Aspect 1). The tip surface of the pressing portion further includes a recessed surface recessed from the suction surface around the suction surface. The peripheral holding portion is annular in shape and has an annular suction surface that suctions and holds the entire peripheral region. The pressing portion and the peripheral holding portion have a sealed structure that seals the gap between the outer edge of the recessed surface and the inner surface of the peripheral holding portion. As a result, in the joining device, when the sheet is adsorbed onto the suction surfaces of the pressing portion and the peripheral holding portion, a sealed space is formed between the suction surfaces. Then, when pressing the first workpiece, the joining device reduces the internal pressure of the sealed space, thereby deforming the portion of the sheet between the suction surface of the pressing portion and the suction surface of the peripheral holding portion toward the recessed surface of the pressing portion.

[0008] According to the first aspect, when the internal pressure of the sealed space is reduced, the difference in level between the adsorption surface and the receding surface of the pressing part can be used to curve or bend the sheet at the outer edge of the adsorption surface, thereby increasing the peel angle of the sheet relative to the first workpiece. Furthermore, by increasing the peel angle in this way, the sheet can be more easily peeled from the first workpiece after the first workpiece is pressed.

[0009] In the joining device according to the above-mentioned aspect 1, the sealed structure may be configured by fitting the pressing portion inside the peripheral holding portion so as to be slidable without any gap (aspect 2).

[0010] According to the above-mentioned aspect 2, it is possible to construct a sealed structure without increasing the number of parts of the device.

[0011] In the joining device according to the above aspect 1 or 2, at least one of the adsorption surfaces of the pressing portion and the peripheral holding portion may be configured to be able to adsorb the back surface of the sheet by vacuum suction, and in such a joining device, the internal pressure of the sealed space may be reduced by the vacuum suction (aspect 3).

[0012] According to the above-mentioned aspect 3, the internal pressure of the sealed space can be reduced by using vacuum suction to adsorb the sheet to the adsorption surface, so there is no need to provide a separate mechanism (pressure reduction section) to reduce the internal pressure of the sealed space, and as a result, the configuration of the joining device does not need to be complicated.

[0013] The joining device according to any one of Aspects 1 to 3 may have the following configuration (Aspect 4). The pressing unit may have a slide pin, which may be configured to slide in a direction perpendicular to the suction surface of the pressing unit and to protrude from a predetermined position within the suction surface by the sliding. In such a joining device, before pressing the first workpiece, the internal pressure of the sealed space may be reduced and the tip of the slide pin may be protruded to a predetermined height from the suction surface of the pressing unit, and then, when pressing the first workpiece, the tip of the slide pin may be retracted until it is flush with the suction surface of the pressing unit.

[0014] According to the fourth aspect, by protruding the tip of the slide pin to a predetermined height from the suction surface of the pressing unit before pressing the first workpiece, the sheet can be deformed into a convex shape on the suction surface of the pressing unit, thereby generating a force (peeling force) to peel the sheet from the first workpiece. At this time, the peel angle of the sheet relative to the first workpiece is large as described above. Therefore, by generating this peeling force, the adhesive force of the first workpiece to the sheet can be efficiently weakened. By weakening the adhesive force between the first workpiece and the sheet before pressing the first workpiece in this way, it becomes even easier to peel the sheet from the first workpiece after pressing (bonding) the first workpiece.

[0015] In the joining device according to the above-mentioned aspect 4, after pressing the first workpiece, when the suction surface of the pressing part is retracted from the surface of the second workpiece, only the suction surface of the pressing part may be retracted first without retracting the slide pin, thereby pressing the first workpiece with only the slide pin, and then the slide pin may also be retracted (aspect 5).

[0016] According to the above-mentioned aspect 5, by first retracting only the suction surface of the pressing part without retracting the slide pin, the sheet can be peeled up to the periphery of the slide pin, and at that time, it becomes easier to generate a peel angle between the sheet and the first workpiece, and as a result, it becomes even easier to peel the sheet from the first workpiece after the first workpiece is pressed (joined).

[0017] According to the present invention, in a joining technique for a workpiece attached to the surface of a sheet, it is possible to easily peel the sheet from the workpiece after joining, thereby improving the peeling speed while suppressing adverse effects on the workpiece.

[0018] FIG. 1(A) is a conceptual diagram showing a bonding apparatus according to an embodiment, and FIG. 1(B) is a conceptual diagram showing an enlarged view of a pressing mechanism and its surrounding configuration provided in the bonding apparatus. FIG. 2 is a conceptual diagram showing the configuration at each point of an attitude adjustment mechanism that supports a piezo stage at three points. FIG. 3(A) is a conceptual diagram showing a state change of the bonding apparatus caused by the execution of a bonding process, and FIG. 3(B) is a conceptual diagram showing the next state change. FIG. 4(A) is a conceptual diagram showing an enlarged view of the pressing mechanism and its surrounding configuration of the bonding apparatus in the state shown in FIG. 3(B), and FIG. 4(B) is an enlarged view of area J1 in FIG. 4(A). FIG. 5 is a conceptual diagram showing a state change of the bonding apparatus caused by the execution of a bonding process. FIG. 6 is a conceptual diagram showing a state change of the bonding apparatus caused by the execution of a bonding process. FIG. 7(A) is a conceptual diagram showing a state change of the bonding apparatus caused by the execution of a bonding process, and FIG. 7(B) is an enlarged view of area J2 in FIG. 7(A). FIG. 8A is a conceptual diagram showing a state change of the bonding apparatus caused by the execution of the bonding process, and FIG. 8B is a conceptual diagram showing the next state change.

[0019] [1] Embodiment [1-1] Bonding Apparatus Fig. 1(A) is a conceptual diagram showing a bonding apparatus according to an embodiment. This bonding apparatus presses a chip (such as an LSI or IC, hereinafter referred to as a "first workpiece W1") against the surface of a substrate (such as a wafer, hereinafter referred to as a "second workpiece W2") to bond them together, and includes a holding mechanism 1, a pressing mechanism 2, an alignment stage 3, a detection sensor 4, and a control device 5.

[0020] The holding mechanism 1 includes a sheet holding unit 11 , a table 12 , and a drive unit 13 .

[0021] The sheet holding unit 11 is a part that holds the peripheral edge of an elastically deformable sheet Sw (such as a dicing tape) in a tensioned state. In this embodiment, such a sheet Sw is prepared with a plurality of first workpieces W1 attached to one side of the sheet Sw, and is held by the sheet holding unit 11 with the one side facing downward.

[0022] The table 12 is a portion that holds the second workpiece W2 below the sheet Sw held by the sheet holding unit 11, and is equipped with a chuck function (such as vacuum suction or electrostatic chuck) for fixing the second workpiece W2. A circuit is formed on the second workpiece W2, and a predetermined position corresponding to the circuit (specifically, a predetermined position that can be connected to the circuit) is set on the surface of the second workpiece W2 as a joining position Pt for the first workpiece W1. Therefore, the second workpiece W2 is held on the table 12 with the joining surface with the first workpiece W1 (the surface where the joining position Pt of the first workpiece W1 is provided) facing upward.

[0023] The drive unit 13 is a mechanism that enables the table 12 to move up and down and adjust its position in a horizontal plane, and is composed of, for example, a ball screw and a motor. When joining one workpiece (hereinafter referred to as the "target workpiece Wt") selected from the plurality of first workpieces W1 attached to the sheet Sw at the corresponding joining position Pt, this position adjustment (position adjustment that does not require high precision) can be performed to position the joining position Pt opposite the target workpiece Wt before joining the workpieces. After this position adjustment, the target workpiece Wt is then positioned (aligned) with high precision relative to the joining position Pt by the piezo stage 31, which will be described later.

[0024] In this embodiment, the joining device is configured to be able to press a plurality of first workpieces W1 attached to a sheet Sw one by one onto the surface of a second workpiece W2 (specifically, at the respective corresponding joining positions Pt), thereby joining the first workpieces W1 to the second workpiece W2. More specifically, this is as follows.

[0025] The pressing mechanism 2 includes a pressing portion 21 , a peripheral holding portion 22 , and driving portions 23 and 24 .

[0026] The pressing unit 21 presses the target workpiece Wt, which is attached to the sheet Sw, against the surface of the second workpiece W2. Specifically, a suction surface 21p is formed on the tip surface 21a of the pressing unit 21 (the lower surface in the example of FIG. 1A ) to hold the target workpiece Wt via the sheet Sw by adsorbing the back surface of the sheet Sw. In this embodiment, the suction surface 21p has a configuration (area, shape, etc.) that enables it to hold only the target workpiece Wt via the sheet Sw. Furthermore, the suction surface 21p is configured to adsorb the back surface of the sheet Sw by vacuum suction. Furthermore, the pressing unit 21 is configured to be movable up and down by the power of the drive unit 23. A more specific configuration will be described later, but the pressing unit 21 is configured to be movable up and down independently of the peripheral holding unit 22, which will be described below.

[0027] With such a pressing unit 21, the target workpiece Wt can be held by its suction surface 21p, and then the pressing unit 21 can be lowered to bring the suction surface 21p closer to the surface of the second workpiece W2, thereby pressing the target workpiece Wt against the surface of the second workpiece W2 (see Figure 7 (A)).

[0028] The peripheral holding portion 22 is a portion that holds the peripheral area of ​​the area of ​​the sheet Sw to which the target workpiece Wt is attached when the target workpiece Wt is pressed. Specifically, the peripheral holding portion 22 is configured in an annular shape and has an annular suction surface 22p that suctions and holds the entire peripheral area. In this embodiment, this suction surface 22p is configured to be able to suction the back surface of the sheet Sw by vacuum suction. In addition, the peripheral holding portion 22 is configured to be able to move up and down by the power of the drive unit 24.

[0029] With this peripheral holding unit 22, when the pressing unit 21 presses the target workpiece Wt, the periphery of the area of ​​the sheet Sw to which the target workpiece Wt is attached can be held in place by the suction surface 22p (see FIG. 7A). This allows the sheet Sw to bend appropriately inside the suction surface 22p when the target workpiece Wt is pressed.

[0030] Furthermore, the pressing mechanism 2 has the following configuration. FIG. 1B is a conceptual diagram showing an enlarged view of the pressing mechanism 2 and its surrounding configuration. As shown in this figure, the tip surface 21a of the pressing portion 21 has a recessed surface 21q that is recessed from the suction surface 21p around the periphery of the suction surface 21p. As a result, the tip surface 21a is formed in a table shape with a raised central portion. The pressing portion 21 and the peripheral holding portion 22 have a sealed structure that seals the gap between the outer edge of the recessed surface 21q and the inner surface of the peripheral holding portion 22. As a result, when the sheet Sw is attracted to the suction surface 21p of the pressing portion 21 and the suction surface 22p of the peripheral holding portion 22, a sealed space Qs can be formed between these suction surfaces 21p and 22p (see FIGS. 3B and 4A).

[0031] In this embodiment, the above-mentioned sealed structure is configured by fitting the pressing portion 21 tightly and slidably inside the peripheral holding portion 22 (see FIG. 1(B)). This makes it possible to construct a sealed structure without increasing the number of parts of the joining device.

[0032] With this sealed structure, by reducing the internal pressure of the sealed space Qs when pressing the first workpiece W1, it becomes possible to deform the portion of the sheet Sw between the suction surface 21p of the pressing portion 21 and the suction surface 22p of the peripheral holding portion 22 toward the receding surface 21q of the pressing portion 21 (see FIG. 4A). In this embodiment, the internal pressure of the sealed space Qs is reduced by vacuum suction when the sheet Sw is adsorbed onto the suction surfaces 21p and 22p.

[0033] This allows the sheet Sw to bend or curve at the outer periphery of the adsorption surface 21p by utilizing the step between the adsorption surface 21p and the receding surface 21q of the pressing portion 21 (see FIG. 4A), and as a result, it becomes possible to increase the peel angle θp of the sheet Sw with respect to the first workpiece W1 (see FIG. 4B).Increasing the peel angle θp in this way makes it easier to peel the sheet Sw from the first workpiece W1 after pressing the first workpiece W1.

[0034] Furthermore, since the internal pressure of the sealed space Qs can be reduced by using vacuum suction to adsorb the sheet Sw to the adsorption surfaces 21p and 22p, there is no need to provide a separate mechanism (pressure reduction section) to reduce the internal pressure of the sealed space Qs, and as a result, the configuration of the joining device does not need to be complicated.

[0035] In addition to the above configuration, the pressing unit 21 has a slide pin 211 (see FIG. 1B). This slide pin 211 is configured to be able to slide in a direction perpendicular to the adsorption surface 21p of the pressing unit 21 and to be able to protrude from a predetermined position within the adsorption surface 21p by this sliding. In this embodiment, the predetermined position is set to be the center position of the adsorption surface 21p. The slide pin 211 slides using the power of a driving unit 212.

[0036] More specifically, the pressing portion 21 has a guide hole 210 for slidably installing a slide pin 211, the guide hole 210 being open to the suction surface 21p of the pressing portion 21. The slide pin 211 can slide along the guide hole 210 and can reciprocate between a position where the tip is retracted into the guide hole 210 (see FIG. 4A) and a position where the tip is protruding from the guide hole 210 (see FIG. 8A). In this embodiment, the slide pin 211 is slidably fitted into the guide hole 210 without any gaps so that the inside of the guide hole 210 is also vacuumed during vacuum suction. The action and function of the slide pin 211 will be described in detail later.

[0037] The alignment stage 3 (see FIG. 1A) is a combination of multiple stages that enables high-speed and high-precision position adjustment of the pressing mechanism 2. Specifically, the alignment stage 3 includes a piezo stage 31 and a wide-area stage 32 that allows position adjustment over a wider range than the piezo stage 31. The piezo stage 31 is mounted on the wide-area stage 32, and the pressing mechanism 2 is mounted on the piezo stage 31. The piezo stage 31 uses a piezo element as its stage drive source, allowing for high-precision (nanometer-order precision) position adjustment. On the other hand, the wide-area stage 32 uses a ball screw and a motor as its stage drive source, allowing for high-speed movement of the stage over a wide range.

[0038] With this alignment stage 3, the position of the pressing mechanism 2 can be adjusted in two stages using the wide-area stage 32 and the piezo stage 31. Specifically, the wide-area stage 32 allows the pressing mechanism 2 to be moved at high speed over a wide range without requiring high accuracy, and then the piezo stage 31 allows the position of the pressing mechanism 2 to be adjusted with high accuracy (nanometer-order accuracy).

[0039] Therefore, when aligning the target workpiece Wt with the joining position Pt provided on the surface of the second workpiece W2, the wide stage 32 enables the pressing mechanism 2 to be moved at high speed to a position where the target workpiece Wt can be held from the back side (in other words, to a position above the corresponding joining position Pt).

[0040] Furthermore, because the sheet Sw is elastically deformable, even after the target workpiece Wt is held on the suction surface 21p via the sheet Sw, the position of the pressing mechanism 2 (i.e., the position of the target workpiece Wt) can be adjusted by the piezo stage 31 while the sheet Sw is elastically deforming. Therefore, the target workpiece Wt can be aligned with respect to the joining position Pt with high precision by the piezo stage 31 without being affected by the sheet Sw. This makes it possible to significantly improve the accuracy of alignment with respect to the joining position Pt.

[0041] In this way, the joining device of this embodiment can achieve both high-speed movement of the pressing mechanism 2 over a wide range and high-precision position adjustment of the target workpiece Wt relative to the joining position Pt. As a result, even if the joining positions Pt are scattered over a wide range, it is possible to quickly and highly accurately align the target workpiece Wt relative to the joining position Pt one by one.

[0042] In this embodiment, the alignment stage 3 further includes an attitude adjustment mechanism 33 (see FIG. 2) that enables adjustment of the attitude of the piezo stage 31 relative to the wide stage 32. Specifically, the attitude adjustment mechanism 33 is configured to support the piezo stage 31 relative to the wide stage 32 at three points.

[0043] 2 is a conceptual diagram showing the configuration at each point of the attitude adjustment mechanism 33 that supports the piezo stage 31 at three points. At each point, the attitude adjustment mechanism 33 is configured by erecting a piezo actuator 331, which can adjust the protrusion amount of a movable part 331A, on the wide stage 32, and supporting the piezo stage 31 by bringing the tip of the movable part 331A into contact with the back surface of the piezo stage 31. The example of FIG. 2 also shows a case where a main body 331B of the piezo actuator 331 is connected to the piezo stage 31 via an annular leaf spring 332 in order to stabilize the support state of the piezo stage 31 by the piezo actuator 331.

[0044] Such an attitude adjustment mechanism 33 makes it possible to adjust the attitude of the piezo stage 31 so that the piezo stage 31 is parallel to the wide stage 32 .

[0045] Furthermore, when the target workpiece Wt is pressed against the surface of the second workpiece W2, a force equivalent to the pressure generated at that time (a reaction force acting on the piezo stage 31 at that time) is concentrated at three points (piezo actuators 331) supporting the piezo stage 31. Therefore, the posture adjustment mechanism 33 is equipped with pressure sensors 333 that measure the force (a force equivalent to the pressure) applied to the piezo stage 31 at three points (see FIG. 2). This allows the pressure sensors 333 to measure the pressure generated when the target workpiece Wt is pressed against the surface of the second workpiece W2.

[0046] The detection sensor 4 (see FIG. 1A) is a sensor that detects alignment marks formed on the first workpiece W1 and the second workpiece W2.

[0047] In this embodiment, each first workpiece W1 and a portion of the second workpiece W2 where the joining position Pt of the first workpiece W1 is located constitute a pair of joining targets to be joined together. A pair of joining targets (the target workpiece Wt and the portion of the second workpiece W2 where the joining position Pt of the target workpiece Wt is located) selected from all pairs of joining targets is subjected to alignment before joining. During alignment, the relative positional relationship between the first workpiece W1 and the second workpiece W2 is adjusted (position adjustment that does not require high precision) by the drive unit 13 of the holding mechanism 1 so that the workpieces overlap (face each other) when viewed from a direction perpendicular to a two-dimensional virtual plane (a horizontal plane in this embodiment). Then, the piezo stage 31 performs high-precision position adjustment (alignment) to achieve a predetermined positional relationship (a state in which the position of the target workpiece Wt coincides with the joining position Pt when viewed from the vertical direction).

[0048] In this embodiment, alignment marks are formed for each set of objects to be joined so that the above-described high-precision alignment can be performed for each set of objects to be joined.

[0049] The detection sensor 4 is an image sensor that detects light from a light source 41 (not shown) to obtain an image including the image or shadow of the alignment mark (the image or shadow of the mark on the target workpiece Wt and the corresponding mark on the second workpiece W2). In this embodiment, IR light (infrared light) is used as the light from the light source 41, and materials that can transmit IR light are used for the sheet Sw and the table 12. Note that the IR light may be extracted by passing the light from the light source 41 through a bandpass filter.

[0050] The detection sensor 4 is also installed on the wide stage 32 together with the piezo stage 31. Therefore, when it is desired to obtain an image including an image of the alignment mark with the detection sensor 4, the light source 41 is positioned so that light is irradiated onto the alignment mark from the rear side of the sheet Sw (the upper side in FIG. 1A). This allows the detection sensor 4 to detect light reflected from the alignment mark. On the other hand, when it is desired to obtain an image including the shadow of the alignment mark with the detection sensor 4, the light source 41 is positioned so that light is irradiated onto the alignment mark from the rear side of the table 12 (the lower side in FIG. 1A). This allows the detection sensor 4 to detect transmitted light that casts a shadow on the alignment mark.

[0051] Furthermore, in this embodiment, light incident on the suction surface 21p of the pressing unit 21 from the alignment mark side is used to acquire an image (an image including an image of the alignment mark or a shadow) by the detection sensor 4. Specifically, this is as follows: The pressing mechanism 2 is formed with an optical path Rm that transmits light incident on the suction surface 21p of the pressing unit 21 from the alignment mark side and guides it to the detection sensor 4 (see FIG. 1A). In this embodiment, in order to realize the formation of such an optical path Rm, the pressing unit 21 is made of a material (such as quartz or acrylic) that is capable of transmitting IR light.

[0052] With this detection sensor 4 and related configuration, alignment using the alignment mark (correction of misalignment) can be performed while observing the alignment mark with the detection sensor 4 provided on the wide stage 32. Therefore, alignment using the alignment mark can be performed while the target workpiece Wt is in close proximity to the second workpiece W2 (see FIG. 5). As a result, after alignment, the target workpiece Wt can be pressed against the surface of the second workpiece W2 without causing misalignment (see FIG. 7A). This significantly improves the accuracy of alignment with respect to the joining position Pt.

[0053] The control device 5 is composed of a processing device (such as a CPU) and a storage device (such as a RAM or a ROM), and controls each part of the bonding apparatus (such as the holding mechanism 1, the pressing mechanism 2, the alignment stage 3, and the detection sensor 4) in accordance with a control program installed in the bonding apparatus. In this embodiment, the control device 5 can execute the bonding process described below.

[0054] Here, before being installed in the bonding device, the control program may be stored in a readable state on a portable storage medium (for example, a flash memory, etc.), or may be stored in a downloadable state on another server, etc. The bonding process described below is not limited to being realized by software through the execution of a program, but may also be realized by hardware using a processing circuit built in the bonding device.

[0055] [1-2] Bonding Process FIGS. 3A to 8B are conceptual diagrams sequentially showing the state changes of the bonding device that occur as the bonding process is performed.

[0056] When the joining process is started, the control device 5 first controls the wide stage 32 to move the pressing mechanism 2 at high speed to a position where the target workpiece Wt can be held from the back side (in other words, a position above the corresponding joining position Pt) in order to align the target workpiece Wt with the joining position Pt provided on the surface of the second workpiece W2 (step S101, see FIG. 3A). At this time, the control device 5 controls the drive unit 13 to adjust the position of the table 12 while observing alignment marks (a mark on the target workpiece Wt and a corresponding mark on the second workpiece W2) provided on the target workpiece Wt and the joining position Pt with the detection sensor 4, thereby also performing position adjustment (position adjustment that does not require high precision) to make the joining position Pt face the target workpiece Wt.

[0057] After step S101, the control device 5 controls the drive units 23 and 24 of the pressing mechanism 2 to lower the pressing unit 21 and the peripheral holding unit 22, thereby vacuum-adsorbing the back surface of the area of ​​the sheet Sw where the target workpiece Wt is attached to the suction surface 21p of the pressing unit 21, and vacuum-adsorbing the back surface of the surrounding area to the suction surface 22p of the peripheral holding unit 22 (step S102, see FIG. 3B). At this time, the control device 5 aligns the suction surface 21p of the pressing unit 21 and the suction surface 22p of the peripheral holding unit 22 on the same plane. The control device 5 also controls the drive unit 212 to retract the tip of the slide pin 211 into the guide hole 210 (see FIG. 4A).

[0058] As a result, the target workpiece Wt is held on the suction surface 21p of the pressing portion 21 via the sheet Sw, and the peripheral area of ​​the area of ​​the sheet Sw to which the target workpiece Wt is attached is held on the suction surface 22p of the peripheral holding portion 22.

[0059] In step S102, the sheet Sw is attracted to the suction surface 21p of the pressing unit 21 and the suction surface 22p of the peripheral holding unit 22, thereby forming an enclosed space Qs between the suction surfaces 21p and 22p. The internal pressure of the enclosed space Qs is reduced by vacuum suction on the suction surfaces 21p and 22p.

[0060] As a result, the portion of the sheet Sw between the suction surface 21p of the pressing unit 21 and the suction surface 22p of the peripheral holding unit 22 is deformed toward the receding surface 21q of the pressing unit 21. This deformation of the sheet Sw allows the sheet Sw to be curved or bent at the outer edge of the suction surface 21p of the pressing unit 21 (see FIG. 4A), which results in an increase in the peel angle θp of the sheet Sw relative to the first workpiece W1 (see FIG. 4B). In this embodiment, the peel angle θp gradually increases by lowering the pressing unit 21 while keeping the peripheral holding unit 22 in the same position.

[0061] Increasing the peel angle θp in this manner makes it easier to peel the sheet Sw from the first workpiece W1 after the first workpiece W1 is pressed against it. In other words, it becomes easier to peel the sheet Sw from the first workpiece W1 after the first workpiece W1 is pressed against it (joined).

[0062] After step S102, the control device 5 controls the piezo stage 31 to adjust the position of the pressing mechanism 2 with high precision (nanometer-order precision) (step S103; see FIG. 5).

[0063] Specifically, the control device 5 adjusts the position of the target workpiece Wt with high precision so that the two corresponding marks are accurately overlapped while observing an image including the images or shadows of the alignment marks provided at the target workpiece Wt and the joining position Pt (the images or shadows of the mark on the target workpiece Wt and the corresponding mark on the second workpiece W2) using the detection sensor 4. This allows the target workpiece Wt to ​​be aligned with the joining position Pt with high precision.

[0064] After step S103, the control device 5 causes the tip of the slide pin 211 to protrude to a predetermined height from the suction surface 21p of the pressing portion 21 while maintaining the internal pressure of the sealed space Qs reduced before pressing the first workpiece W1 (step S104; see Figure 6).

[0065] This allows the sheet Sw to be deformed into a convex shape on the suction surface 21p of the pressing unit 21, and as a result, a force (peeling force) that peels the sheet Sw from the first workpiece W1 can be generated. Here, the predetermined height is set so that even if the sheet Sw is deformed into a convex shape on the suction surface 21p, there is no adverse effect on the first workpiece W1 (such as damage to the first workpiece W1 due to bending of the first workpiece W1).

[0066] Furthermore, at this time, the peel angle θp of the sheet Sw relative to the first workpiece W1 has already become large as described above. Therefore, by generating the peel force, the adhesive force of the first workpiece W1 to the sheet Sw can be efficiently weakened. By weakening the adhesive force between the first workpiece W1 and the sheet Sw before pressing the first workpiece W1 in this way, it becomes even easier to peel the sheet Sw from the first workpiece W1 after pressing (bonding) the first workpiece W1.

[0067] After step S104, the control device 5 controls the drive unit 23 of the pressing mechanism 2 to lower the pressing unit 21, thereby pressing the target workpiece Wt against the surface of the second workpiece W2 (step S105, see FIG. 7A). At this time, the control device 5 controls the drive unit 212 to retract the tip of the slide pin 211 until it is flush with the suction surface 21p of the pressing unit 21. The control device 5 also lowers the pressing unit 21 until the output of the pressure sensor 333 reaches the target value (in other words, until the pressing force reaches the target value).

[0068] Furthermore, in step S105, the control device 5 keeps the peripheral holding unit 22 in the same position when lowering the pressing unit 21. This allows the sheet Sw to bend appropriately when pressing the target workpiece Wt, and as a result, it becomes possible to gradually increase the peel angle θp of the sheet Sw with respect to the first workpiece W1 (see FIG. 7B).

[0069] After step S105, the control device 5 controls the drive unit 23 of the pressing mechanism 2 to raise the pressing unit 21, thereby retracting the suction surface 21p of the pressing unit 21 from the surface of the second workpiece W2 (step S106, see FIG. 8A). At this time, the control device 5 further controls the drive unit 212 to retract only the suction surface 21p of the pressing unit 21 first without retracting the slide pin 211, thereby pressing the first workpiece W1 with only the slide pin 211. Thereafter, the control device 5 controls the drive unit 212 to retract the slide pin 211 as well (step S107, see FIG. 8B).

[0070] In this way, by first retracting only the suction surface 21p of the pressing portion 21 without retracting the slide pin 211, the sheet Sw can be peeled off up to the periphery of the slide pin 211, and at that time, it becomes easier to generate a peeling angle θp between the sheet Sw and the first workpiece W1, and as a result, it becomes even easier to peel the sheet Sw from the first workpiece W1 after pressing (joining) the first workpiece W1.

[0071] As described above, according to the present embodiment, in a joining technique for joining a first workpiece W1 attached to the surface of a sheet Sw, it is possible to easily peel the sheet Sw from the first workpiece W1 after joining, thereby improving the peeling speed while suppressing adverse effects on the first workpiece W1. The control device 5 then performs such joining processing (steps S101 to S107) for each of the multiple first workpieces W1 attached to the sheet Sw.

[0072] [2] Modifications [2-1] First Modification In the above-described joining device, the sealing structure that seals the gap between the outer peripheral edge of the receding surface 21q and the inner peripheral surface of the peripheral holding portion 22 may be formed by interposing a bellows or an elastic body (such as a leaf spring) between them.

[0073] [2-2] Second Modification In the above-described joining device, the pressing mechanism 2 is not limited to being configured so that both the suction surface 21p of the pressing portion 21 and the suction surface 22p of the peripheral holding portion 22 can adsorb the back surface of the sheet Sw by vacuum suction, but may be appropriately modified to be configured so that only one of the suction surfaces can adsorb the back surface of the sheet Sw by vacuum suction.

[0074] [2-3] Third Modification In the above-described bonding device, the pressing mechanism 2 may be appropriately modified to a configuration that reduces the internal pressure of the sealed space Qs, independent of the configuration that adsorbs the sheet Sw to the adsorption surfaces 21 p and 22 p by vacuum suction. Specifically, the pressing mechanism 2 may be appropriately modified to a configuration that includes a dedicated pressure reducing unit for reducing the internal pressure of the sealed space Qs.

[0075] [2-4] Fourth Modification In the control process described above, the control device 5 may perform the following process. The control device 5 measures the pressure generated during pressing in step S105 using the pressure sensors 333 at three points supporting the piezo stage 31. The control device 5 may then feed back the three measured values ​​obtained at that time to the control of the attitude adjustment mechanism 33, thereby adjusting the attitude of the piezo stage 31 so that the three measured values ​​are all within a predetermined range the next time pressing is performed. Here, the predetermined range is a range set so that it is permissible to estimate that the piezo stage 31 is parallel to the wide-area stage 32 if all three measured values ​​are within that range.

[0076] Specifically, the control device 5 uses the three measurement values ​​to calculate values ​​such as the deviation of the measurement value from a reference value (such as a central value) within a specified range and the difference between the measurement values, and based on the calculated values, can adjust the protrusion amount of the movable part 331A of each piezo actuator 331 so that the next time it is pressed, all three measurement values ​​will be within the specified range.

[0077] According to this control process, each time the target workpiece Wt is pressed against the surface of the second workpiece W2, the posture of the piezo stage 31 can be adjusted so that the piezo stage 31 is parallel to the wide stage 32. This makes it possible to always keep the piezo stage 31 parallel to the wide stage 32.

[0078] [2-5] Fifth Modification The above-described joining device may be appropriately modified to join the first workpiece W1 and the second workpiece W2 with their joining surfaces facing laterally (horizontally).

[0079] [2-6] Sixth Modification The above-described joining device is not limited to joining a chip (first workpiece W1) to a substrate (second workpiece W2), but can also be applied to joining a chip (first workpiece W1) to another chip (second workpiece W2).

[0080] The above-described embodiments and modifications should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined not by the above-described embodiments and modifications, but by the claims. Furthermore, the scope of the present invention is intended to include all modifications that are equivalent to the scope of the claims and fall within the scope thereof.

[0081] Furthermore, from the above-described embodiments and variant examples, a portion of the configuration of the joining device may be extracted as the subject of the invention, or a portion or all of the joining process (including the corresponding control method and joining method), or even a program for executing them, etc. may be extracted.

[0082] REFERENCE SIGNS LIST 1 Holding mechanism 2 Pressing mechanism 3 Alignment stage 4 Detection sensor 5 Control device 11 Sheet holding section 12 Table 13 Drive section 21 Pressing section 21a Tip surface 21p Suction surface 21q Retraction surface 22 Periphery holding section 22p Suction surface 23, 24 Drive section 31 Piezo stage 32 Wide stage 33 Attitude adjustment mechanism 41 Light source Pt Bonding position Qs Sealed space Rm Optical path Sw Sheet W1 First workpiece W2 Second workpiece Wt Target workpiece 210 Guide hole 211 Slide pin 212 Drive section 331 Piezo actuator 331A Movable section 331B Main body section 332 Leaf spring 333 Pressure sensor θp Peeling angle

Claims

1. A sheet holding section that holds the peripheral edge of a sheet having a first workpiece attached to its surface; a pressing section that has an adsorption surface formed on its tip surface that holds the first workpiece via the sheet by adsorbing the back surface of the sheet, and that can press the first workpiece against the surface of a second workpiece by bringing the adsorption surface close to the surface of the second work; and a peripheral holding section that holds the peripheral area of ​​the sheet to which the first workpiece is attached when the first workpiece is pressed, wherein a recessed surface that is recessed from the adsorption surface is further formed on the tip surface of the pressing section around the adsorption surface, and the peripheral holding section is itself configured in an annular shape and has an annular adsorption surface that adsorbs and holds the entire peripheral area, and the pressing section and the peripheral holding section have an airtight structure that seals the gap between the outer edge of the recessed surface and the inner surface of the peripheral holding section, so that when the sheet is adsorbed onto the adsorption surface of the pressing section and the adsorption surface of the peripheral holding section, an airtight space is formed between these adsorption surfaces, A joining device that, when pressing the first workpiece, reduces the internal pressure of the sealed space, thereby deforming the portion of the sheet between the adsorption surface of the pressing portion and the adsorption surface of the peripheral holding portion toward the receding surface of the pressing portion.

2. The joining device according to claim 1, wherein the sealing structure is configured by fitting the pressing portion tightly and slidably inside the peripheral holding portion.

3. A joining device as described in claim 1 or 2, wherein at least one of the suction surfaces of the pressing portion and the suction surface of the peripheral holding portion is configured to be able to adsorb the back surface of the sheet by vacuum suction, and the internal pressure of the sealed space is reduced by this vacuum suction.

4. A joining device according to any one of claims 1 to 3, wherein the pressing part has a slide pin, and the slide pin is configured to be able to slide in a direction perpendicular to the suction surface of the pressing part and to be able to protrude from a predetermined position within the suction surface by sliding, and before pressing the first workpiece, the internal pressure of the sealed space is reduced and the tip of the slide pin is caused to protrude to a predetermined height from the suction surface of the pressing part, and thereafter, when pressing the first workpiece, the tip of the slide pin is retracted until it is at the same height as the suction surface of the pressing part.

5. A joining device as described in claim 4, wherein, after pressing the first workpiece, when the suction surface of the pressing part is retracted from the surface of the second workpiece, only the suction surface of the pressing part is retracted first without retracting the slide pin, thereby pressing the first workpiece with only the slide pin, and then the slide pin is also retracted.

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