Bonding stage

Abstract

To allow a warped wafer to be fitted to the surface of a bonding stage and vacuum-sucked with a simple structure.SOLUTION: A bonding stage 10 vacuum-adsorbs a wafer 70 onto its surface 11, and includes a recess 20 provided on the surface 11 for vacuum-adsorbing the center of the wafer 70, and a spiral groove 30 provided on the surface 11, communicating with the recess 20, and extending from the recess 20 toward the periphery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bonding stage structure. [Background technology]

[0002] Patent Document 1 discloses an electronic component mounting table that includes a main body, a chuck, and a buffer plate. The main body is provided with vacuum holes for introducing a vacuum. The chuck is made of a porous material. The buffer plate is a plate member that is sandwiched between the main body and the chuck, and has multiple grooves on its surface. The grooves communicate with the vacuum holes in the main body to create a vacuum, and the electronic component is adsorbed and fixed to the surface of the chuck, which is made of a porous material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-179207 Summary of the Invention [Problem to be solved by the invention]

[0004] A bonding method is used in which semiconductor chips are mounted in multiple stages on the surface of a wafer. In this case, when the first-stage semiconductor chip is bonded to the surface of the wafer, the difference in thermal expansion between the wafer and the semiconductor chip causes the wafer to warp. Therefore, when bonding the second-stage semiconductor chip, it is necessary to use a clamper to press the warped wafer against the surface of the bonding stage, align the warped wafer with the surface of the bonding stage, and then vacuum-suck the wafer onto the surface of the bonding stage. This results in problems such as a complex bonding stage structure and a time-consuming setup for vacuum-sucking the wafer.

[0005] Therefore, an object of the present disclosure is to vacuum-suck a warped wafer by making it conform to the surface of a bonding stage using a simple configuration. [Means for solving the problem]

[0006] The bonding stage disclosed herein is a bonding stage that vacuum-adsorbs a plate-shaped object onto its surface, and is characterized by having an adsorption portion provided on the surface that vacuum-adsorbs the center of the object, and a groove provided on the surface that is connected to the adsorption portion and extends from the adsorption portion toward the periphery to adsorb the object from the center toward the periphery.

[0007] As a result, the bonding stage of the present disclosure can vacuum-suck a warped, plate-shaped object, such as a wafer, by simply vacuum suction without using a clamper or the like, so that the wafer conforms to the surface.

[0008] In the bonding stage of the present disclosure, the groove may be a spiral groove extending from the suction portion toward the periphery.

[0009] This allows the bonding stage of the present disclosure to vacuum-suck the disk-shaped wafer evenly onto the surface of the bonding stage.

[0010] In the bonding stage of the present disclosure, the spiral groove may have a cross-sectional area that decreases toward the periphery.

[0011] The smaller the cross-sectional area of ​​the spiral groove, the faster the air flow rate in the spiral groove, resulting in a higher vacuum level. Therefore, the smaller the cross-sectional area of ​​the spiral groove, the more easily the warped portion of the wafer can be vacuum-adsorbed to the surface of the bonding stage. Therefore, by reducing the cross-sectional area of ​​the spiral groove toward the periphery, the outer periphery of a warped wafer with a large amount of upward deformation can be conformed to the surface of the bonding stage and vacuum-adsorbed. Furthermore, by making the cross-sectional area of ​​the groove in the center larger than that of the periphery, the air resistance of the spiral groove is reduced, increasing the amount of air sucked in, and allowing the warped wafer to be vacuum-adsorbed to the surface of the bonding stage in a short period of time.

[0012] The bonding stage of the present disclosure may include a plurality of branch grooves arranged between two radially adjacent arc portions of the spiral groove and branching radially inward from the radially outer arc portion.

[0013] This allows the suction force of the bonding stage to be increased.

[0014] In the bonding stage of the present disclosure, the spiral groove may be a plurality of spiral grooves, which may communicate with different positions of the suction portion and extend parallel to each other from the suction portion toward the peripheral portion.

[0015] This allows the suction force of the bonding stage to be increased.

[0016] In the bonding stage of the present disclosure, the spiral groove has a cross-sectional area of ​​0.2 mm 2 The width may be greater than the depth, and the depth may be 0.1 mm or more. 2 The width may be greater than the depth, and the depth may be 0.1 mm or more.

[0017] This increases the air flow rate in the spiral groove, and increases the degree of vacuum in the spiral groove to a level that allows the warped wafer to be adsorbed.

[0018] In the bonding stage of the present disclosure, the spiral groove may be a square spiral groove.

[0019] This allows the warped square substrate to be vacuum-adsorbed so that it conforms to the surface of the bonding stage.

[0020] In the bonding stage of the present disclosure, a plurality of suction portions are provided on the surface, and the grooves are a plurality of spiral grooves of different widths, which may communicate with different suction portions and extend parallel to each other from each suction portion toward the peripheral portion.

[0021] This allows the cross-sectional area of ​​the spiral groove to be selected depending on the degree of warpage of the warped wafer. For example, for a wafer with a large warpage, a spiral groove with a small cross-sectional area can be used to gradually conform the wafer to the surface of the bonding stage, and for a wafer with a small warpage, a spiral groove with a large cross-sectional area can be used to quickly conform the wafer to the surface of the bonding stage.

[0022] In the bonding stage of the present disclosure, the spiral grooves may have a cross-sectional area that decreases toward the periphery.

[0023] This allows the outer periphery of a warped wafer with a large amount of upward deformation to be vacuum-adsorbed by conforming to the surface of the bonding stage, which also reduces the air resistance of the spiral groove and increases the amount of air sucked in, allowing the warped wafer to be vacuum-adsorbed to the surface of the bonding stage in a short period of time.

[0024] In the bonding stage of the present disclosure, the grooves may be a plurality of radial grooves extending radially from the suction portion toward the periphery.

[0025] This allows the warped wafer to be vacuum-sucked and conform to the surface of the bonding stage in a short time.

[0026] In the bonding stage of the present disclosure, the cross-sectional area of ​​the plurality of radial grooves may decrease toward the periphery. Also, in the bonding stage of the present disclosure, the width of the radial grooves may be 0.05 to 0.1 mm.

[0027] This allows the outer periphery of a warped wafer with a large amount of upward deformation to conform to the surface of the bonding stage and be vacuum-adsorbed.In addition, the air resistance of the radial grooves is reduced, increasing the amount of air sucked in, allowing the warped wafer to be vacuum-adsorbed to the surface of the bonding stage in a short period of time. [Effects of the Invention]

[0028] The present disclosure is capable of vacuum-adsorbing a warped wafer by conforming it to the surface of a bonding stage with a simple configuration. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is a perspective view showing a bonding stage according to the embodiment. [Figure 2] FIG. 2 is a plan view of the bonding stage shown in FIG. [Figure 3] 3 is a cross-sectional view of a state in which the center of a wafer is vacuum-absorbed onto the surface of the bonding stage shown in FIG. 2, taken along the line AA in FIG. 2. [Figure 4] 3 is a cross-sectional view of a state in which the center of the wafer is vacuum-absorbed onto the surface of the bonding stage shown in FIG. 2, taken along the line BB in FIG. 2. [Figure 5] 3 is a cross-sectional view of the bonding stage and the wafer showing the initial state in which the warped wafer is placed on the surface of the bonding stage, taken along the CC cross section shown in FIG. 2. [Figure 6] FIG. 6 is a cross-sectional view showing the change in the shape of the wafer when a vacuum is created from the recess to the second turn of the spiral groove after the state shown in FIG. 5. [Figure 7] FIG. 7 is a cross-sectional view showing a state after the state shown in FIG. 6, in which the entire spiral groove is evacuated and the entire wafer is vacuum-adsorbed along the surface of the bonding stage. [Figure 8] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 9] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 10] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 11] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 12] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 13] FIG. 10 is a plan view showing a bonding stage according to another embodiment. [Figure 14] FIG. 10 is a plan view showing a bonding stage according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0030] A bonding stage 10 according to an embodiment will now be described with reference to the drawings. As shown in FIG. 1, the bonding stage 10 is a rectangular flat plate member having a recess 20 and a spiral groove 30 formed on a surface 11. The recess 20 is located in the center of the bonding stage 10. A vacuum pipe 12, which is connected to a vacuum device, is connected to the bottom of the recess 20. The spiral groove 30 communicates with the side of the recess 20 and extends from the center toward the periphery of the bonding stage 10. As shown in FIG. 2, the shape of the spiral groove 30 may be, for example, an Archimedes spiral represented by the polar equation r=a*θ, where r is the distance from the center, θ is the angle, and a is a constant.

[0031] When the recess 20 is evacuated by a vacuum device, the spiral groove 30 that communicates with the recess 20 is also evacuated. As a result, the disk-shaped wafer 70 is vacuum-attached to the surface 11 of the bonding stage 10. At this time, the center of the wafer 70 is vacuum-attached to the center of the bonding stage 10. Furthermore, the outer periphery of the wafer 70 is vacuum-attached to the peripheral portion of the bonding stage 10. The circle indicated by the dashed line in FIG. 1 indicates the outer periphery 71 of the area where the wafer 70 is placed. Therefore, the wafer 70 is a plate-shaped object that is vacuum-attached to the bonding stage 10. Furthermore, the recess 20 forms an absorbing portion that vacuum-attaches the wafer 70.

[0032] 3 and 4, the spiral groove 30 has an inner diameter wall 31, an outer diameter wall 32, and a bottom surface 33. The spiral groove 30 has a depth D and a width W. The shape of the spiral groove 30 will be described in detail later.

[0033] The recess 20 may be of any size as long as it can vacuum-suck the center of the warped wafer 70. For example, the recess 20 may be circular with a diameter of about 5 mm to 20 mm. The depth of the recess 20 may be the same as the depth D of the spiral groove 30, or may be deeper. For example, the depth may be 0.1 mm to 0.2 mm.

[0034] Next, the principle and operation of vacuum-chucking a warped wafer 70 will be described with reference to Figures 2 to 7. Figures 5 to 7 are cross-sectional views showing the pressure in the spiral groove 30 and the change in the shape of the wafer 70 when the warped wafer 70 is vacuum-chucking while conforming to the surface 11 of the bonding stage 10. The shaded recesses 20 and spiral grooves 30 in Figures 5 to 7 indicate the recesses 20 and spiral grooves 30 that are evacuated.

[0035] When the semiconductor chip 75 is bonded to the surface of the wafer 70, warpage occurs in the wafer 70 due to the difference in thermal expansion between the wafer 70 and the semiconductor chip 75. As shown in Fig. 5, the wafer 70 to which the semiconductor chip 75 is bonded is warped into a dish shape with the outer periphery curved upward.

[0036] As shown in FIG. 5, a vacuum is applied to a recess 20 located in the center of the bonding stage 10, and the center of a warped wafer 70 is placed on the recess 20. The center of the wafer 70 is then vacuum-adsorbed into the recess 20. When the surface 11 of the spiral groove 30 connected to the recess 20 is blocked by the wafer 70, a square air flow path 35 is formed at the position indicated by line 91 in FIG. 2, as shown in FIG. 3. Air then flows through the air flow path 35 toward the recess 20. The symbol with an X inside a circle in FIG. 3 indicates that the air flows from the front to the back of the page. At this time, the air flow velocity through the air flow path 35 is V1.

[0037] On the other hand, at a position indicated by line 92 in FIG. 2 , slightly away from the recessed portion 20, the warped wafer 70 is not yet vacuum-sucked, as shown in FIG. 4 . At this position, as indicated by the white arrow in FIG. 4 , air is sucked from the gap 34 between the wafer 70 and the surface 11 of the bonding stage 10 toward the spiral groove 30. At this time, the air flow velocity through the gap 34 is V2. The air flowing into the spiral groove 30 then flows into the recessed portion 20 through the square air flow path 35 shown in FIG. 3 . Note that the symbol with an X inside a circle in FIG. 4 indicates that the air is flowing from the front to the back of the page. At this time, the air flow velocity through the spiral groove 30 is V3. This reduces the pressure in the gap 34 and the spiral groove 30 shown in FIG. 4 . If the air flow velocities V2 and V3 are sufficiently fast, the degree of vacuum in the gap 34 and the spiral groove 30 increases, and the warped wafer 70 is vacuum-sucked to the surface 11.

[0038] When the wafer 70 is vacuum-adsorbed onto the spiral groove 30, the wafer 70 and the spiral groove 30 form a rectangular air flow path 35 at the position of the line 92 in FIG. 2 . The air flow path 35 draws air into the gap 34 and the spiral groove 30 on the outer periphery side of the position of the line 92 in FIG. 2 , creating a vacuum in that region of the gap 34 and the spiral groove 30. This causes the wafer 70 on the outer periphery side of the position of the line 92 in FIG. 2 to be vacuum-adsorbed. In this manner, the spiral groove 30 is gradually vacuumed from the center toward the periphery. As shown in FIG. 6 , when a vacuum is created from the recess 20 to the second turn of the spiral groove 30, the portion of the wafer 70 from the center to the second turn of the spiral groove 30 is vacuum-adsorbed to the surface 11. Then, when the entire spiral groove 30 is vacuum-adsorbed, the entire warped wafer 70 is vacuum-adsorbed along the surface 11 of the bonding stage 10, as shown in FIG. 7 . In this way, the bonding stage 10 vacuum-sucks the warped wafer 70 so that it gradually conforms to the surface 11 from the center toward the periphery.

[0039] Here, we will explain the shape of the spiral groove 30 required to gradually vacuum-suck the warped wafer 70 from the center toward the periphery, as described above. As previously explained with reference to Figures 3 and 4, in order to vacuum-suck the wafer 70 into the spiral groove 30, the air flow velocity V3 in the spiral groove 30 must be sufficiently fast. To achieve this, the cross-sectional area of ​​the spiral groove 30 must be small. On the other hand, if the air resistance of the air flow path 35 (see Figure 3) formed by the spiral groove 30 and the wafer 70 becomes large, the air flow rate will decrease, and the air flow velocity V3 will drop. To reduce the resistance of the air flow path 35, the wetted area of ​​the air flow path 35 must be small.

[0040] According to the experimental research of the inventors, the cross-sectional area of ​​the spiral groove 30 is set to 0.2 mm 2 It has been found that the warped wafer 70 can be adsorbed and the resistance of the air flow path 35 can be reduced by making the cross-sectional area of ​​the spiral groove 30 0.2 mm 2 The shape of the spiral groove 30 can be freely set as long as it is equal to or less than this value, but it is preferable that the width W is greater than the depth D and that the depth D is 0.1 mm or more. If the depth D of the spiral groove 30 is less than 0.1 mm, the resistance of the air flow path 35 will be high, and it may be impossible to adsorb to the outer periphery 71, or it may take a long time to adsorb. More preferably, the ratio of the width W to the depth D of the spiral groove 30 may be 3 to 10, W = (3 to 10) × D, and the depth D may be in the range of 0.1 mm to 0.2 mm. Here, as an example of the cross-sectional shape of the spiral groove 30, when the depth D is 0.1 mm, the width W may be 0.3 mm to 1.0 mm. In this case, the cross-sectional area of ​​the spiral groove 30 will be 0.03 mm or less. 2 ~0.1mm 2 In addition, when the depth D is 0.2 mm, the width W may be in the range of 0.6 mm to 1.0 mm. In this case, the cross-sectional area of ​​the spiral groove 30 is 0.12 mm 2 ~0.2mm 2 The cross-sectional area of ​​the spiral groove 30 may be changed as appropriate depending on the vacuum flow path and the exhaust capacity of the vacuum pump. For example, if the vacuum pump has a large exhaust capacity, the cross-sectional area may be set to 0.2 mm 2 It may be larger than

[0041] As described above, the bonding stage 10 can vacuum-suck the warped wafer 70 so that it conforms to the surface 11 of the bonding stage 10 only by vacuum suction without using a clamper or the like.

[0042] Next, a bonding stage 13 according to another embodiment will be described with reference to Fig. 8. The same parts as those in the bonding stage 10 previously described with reference to Figs. 1 to 7 are designated by the same reference numerals, and description thereof will be omitted.

[0043] 8 has a spiral groove 41 consisting of an outer spiral groove 43 on the periphery and an inner spiral groove 42 in the center. The outer spiral groove 43 and the inner spiral groove 42 have the same depth D, the width W3 of the outer spiral groove 43 is narrower than the width W2 of the inner spiral groove 42, and the cross-sectional area of ​​the outer spiral groove 43 is smaller than the cross-sectional area of ​​the inner spiral groove 42.

[0044] As explained above with reference to FIG. 5, the amount of upward deformation of a warped wafer 70 increases toward the outer periphery. On the other hand, as explained above, the smaller the cross-sectional area of ​​the spiral groove 30, the higher the degree of vacuum within the spiral groove 30. Therefore, the smaller the cross-sectional area of ​​the spiral groove 30, the more the highly warped portion of the wafer 70 can be vacuum-attached to the surface 11 of the bonding stage 13. Furthermore, to vacuum-attach the central portion of a wafer 70 with a small amount of warpage, the cross-sectional area may be large; by increasing the cross-sectional area, the air resistance of the air flowing through the air flow path 35 (see FIG. 3) can be reduced, thereby increasing the air flow rate through the spiral groove 30.

[0045] Therefore, in the bonding stage 13, the depth D is kept constant, and the width W3 of the outer spiral groove 43 is made narrower than the width W2 of the inner spiral groove 42. This allows the outer periphery of the warped wafer 70, which has a large amount of upward deformation, to be vacuum-adsorbed while conforming to the surface 11 of the bonding stage 13, and also reduces the resistance of the air flow path 35, thereby increasing the amount of air that can be sucked in. This allows the warped wafer 70 to be vacuum-adsorbed to the surface 11 of the bonding stage 13 in a shorter time than in the bonding stage 10. Here, the cross-sectional shapes of the outer spiral groove 43 and the inner spiral groove 42 are, as explained above, 0.2 mm 2 Hereinafter, the ratio of the widths W2 and W3 to the depth D is set to 3 to 10, and the depth D is set to a range of 0.1 mm to 0.2 mm.

[0046] 8 has been described as including the outer spiral groove 43 and the inner spiral groove 42, but this is not limiting. For example, the width W or cross-sectional area of ​​one spiral groove 30 may be configured to continuously decrease toward the periphery.

[0047] Next, a bonding stage 14 according to another embodiment will be described with reference to Fig. 9. The same parts as those in the bonding stage 10 previously described with reference to Figs. 1 to 7 are designated by the same reference numerals, and description thereof will be omitted.

[0048] 9, the bonding stage 14 has two spiral grooves 46, 47 of the same shape connected to one recess 20. The two spiral grooves 46, 47 communicate with different positions in the recess 20 and extend parallel to each other from the center toward the periphery. Note that the recess 20 is not limited to a single hole and may have any shape that can adsorb the wafer 70, such as a shape with multiple holes on the surface 11, a mesh shape, or a porous shape.

[0049] In this way, by arranging the two spiral grooves 46, 47, the suction force of the bonding stage 14 can be made greater than that of the bonding stage 10. This allows the bonding stage 14 to vacuum-suck the wafer 70, which has a large warp, so that it conforms to the surface 11 of the bonding stage 14.

[0050] Although the bonding stage 14 has been described as having two spiral grooves 46 and 47, it may be configured to have three or more spiral grooves as long as it has multiple spiral grooves, each spiral groove being configured to communicate with a different position of one recess 20.

[0051] Next, a bonding stage 15 according to another embodiment will be described with reference to Fig. 10. The same parts as those in the bonding stage 10 previously described with reference to Figs. 1 to 7 are designated by the same reference numerals, and description thereof will be omitted.

[0052] The bonding stage 15 has two recesses 21, 22 provided in the center of the surface 11, and is equipped with a first spiral groove 51 communicating with the recess 21 and a second spiral groove 52 communicating with the recess 22. The first spiral groove 51 and the second spiral groove 52 extend parallel to each other from the recesses 21, 22 in the center toward the periphery. The first spiral groove 51 and the second spiral groove 52 have the same depth D, and the width W4 of the first spiral groove 51 is narrower than the width W5 of the second spiral groove 52. Thus, the cross-sectional area of ​​the first spiral groove 51 is smaller than the cross-sectional area of ​​the second spiral groove 52.

[0053] As explained above, the smaller the cross-sectional area, the more warped the wafer 70 can be vacuum-sucked. On the other hand, if the cross-sectional area is large, the wafer 70 cannot be vacuum-sucked with a large warp, but the air resistance of the air flow path 35 is low and the air flow rate can be increased. The bonding stage 15 is provided with a first spiral groove 51 having the same depth D and a narrow width W, and a first spiral groove 52 having a wide width W.

[0054] Here, the amount of warpage of the wafer 70 increases as the number of stages of semiconductor chips 75 bonded onto the wafer 70 increases. Therefore, the amount of warpage of the wafer 70 differs depending on the number of stages of semiconductor chips 75 bonded onto the wafer 70.

[0055] When vacuum-absorbing a wafer 70 with a large amount of warpage, the bonding stage 15 can vacuum-absorb the wafer 70 onto the front surface 11 by connecting the recess 21 to a vacuum device and evacuating the first spiral groove 51 over a long period of time. On the other hand, when vacuum-absorbing a wafer 70 with a small amount of warpage, the bonding stage 15 can vacuum-absorb the wafer 70 onto the front surface 11 by connecting the recess 22 to a vacuum device and evacuating the second spiral groove 52 over a short period of time. This allows the bonding stage 15 to vacuum-absorb wafers 70 with different amounts of warpage efficiently onto the front surface 11.

[0056] Next, a bonding stage 16 according to another embodiment will be described with reference to Fig. 11. The same parts as those in the bonding stage 10 previously described with reference to Figs. 1 to 7 are designated by the same reference numerals, and description thereof will be omitted.

[0057] As shown in FIG. 11 , the bonding stage 16 includes a spiral groove 30 and a plurality of branch grooves 57 branching off from the spiral groove 30. The branch grooves 57 are arranged between two radially adjacent arc portions of the spiral groove 30, and branch off from the radially outer arc portion toward the radially inner side. The cross-sectional area of ​​the branch grooves 57 may be the same as that of the spiral groove 30, or may be smaller than that of the spiral groove 30. For example, the depth D and width W may be the same as those of the spiral groove 30, or the depth D may be the same as that of the spiral groove 30 but the width W may be narrower than that of the spiral groove 30. This allows the bonding stage 16 to have a greater suction force than the bonding stage 10 described above.

[0058] Next, a bonding stage 17 of another embodiment will be described with reference to FIG. 12. The bonding stage 17 has radial grooves 61 instead of the spiral grooves 30 of the bonding stage 10 described with reference to FIGS. 1 to 7. The radial grooves 61 extend linearly from the center to the periphery, and are shorter in length than the spiral grooves 30. The bonding stage 17 also has eight radial grooves 61. Therefore, the total cross-sectional area of ​​the radial grooves 61 is larger than the cross-sectional area of ​​the spiral groove 30 described above. Therefore, the cross-sectional area of ​​each radial groove 61 can be smaller than the cross-sectional area of ​​the spiral groove 30. For example, the width W7 of the radial grooves 61 may be narrower than the width W of the spiral groove 30, and the width W7 may be approximately 0.05 mm to 0.1 mm. The depth D may be approximately 0.1 mm, similar to the spiral groove 30. In this case, the cross-sectional area of ​​the radial grooves 61 is 0.005 mm. 2 ~0.01mm 2 The depth D may be greater than 0.1 mm, for example, 0.2 mm.

[0059] As described above, the total cross-sectional area of ​​the radial grooves 61 is larger than the cross-sectional area of ​​the spiral groove 30, and the length is shorter, so the amount of air sucked into the recess 20 is greater. Therefore, compared to the bonding stage 10, the bonding stage 17 can vacuum-suck the warped wafer 70 by making it conform to the surface 11 in a shorter time. Note that even if the total cross-sectional area of ​​the radial grooves 61 is made equal to the cross-sectional area of ​​the spiral groove 30, the length of the radial grooves 61 is shorter than the length of the spiral groove 30, so the amount of air sucked into the recess 20 is greater. Therefore, in this case as well, the bonding stage 17 can vacuum-suck the wafer 70 by making it conform to the surface 11 in a shorter time.

[0060] Next, a bonding stage 18 according to another embodiment will be described with reference to FIG. 13. The bonding stage 18 has radial grooves 62 which narrow in width as they approach the periphery, instead of the radial grooves 61 of the bonding stage 17. The width W8 of the radial grooves 62 may be, for example, about 0.1 mm in the center and about 0.05 mm in the periphery. The depth D may also be about 0.1 mm. In this case, the cross-sectional area of ​​the radial grooves 62 is 0.01 mm at the center.2 , 0.005mm at the periphery 2 This becomes:

[0061] The bonding stage 18 can vacuum-suck the outer periphery of the warped wafer 70, which has a large amount of upward deformation, so that it conforms to the front surface 11.

[0062] Next, a bonding stage 19 according to another embodiment will be described with reference to Fig. 14. The same parts as those in the bonding stage 10 previously described with reference to Figs. 1 to 7 are designated by the same reference numerals and will not be described again.

[0063] The bonding stage 19 is a bonding stage in which the spiral groove 30 of the bonding stage 10 described with reference to FIGS. 1 to 7 is replaced with a square spiral groove 65. The depth D and width W are the same as those of the spiral groove 30. As described with reference to FIG. 8, the cross-sectional area of ​​the square spiral groove 65 may be reduced at the outer portion and increased at the inner portion. The cross-sectional area of ​​the square spiral groove 65 may be configured to continuously narrow toward the periphery. For example, the depth D may be constant, with the width of the square spiral groove 65 reduced at the outer portion and increased at the inner portion. As described with reference to FIG. 9, multiple square spiral grooves 65 may be connected to one recess 20. As described with reference to FIG. 10, two square spiral grooves 65 may be connected to two recesses 21 and 22.

[0064] The bonding stage 19 can vacuum-suck the warped square substrate 78 so that it conforms to the surface 11. Here, the square substrate 78 is a plate-shaped object that the bonding stage 19 vacuum-sucks.

[0065] As described above, the bonding stages 10, 13 to 19 of the embodiment can vacuum-suck the warped wafer 70 so that it conforms to the front surface 11 only by vacuum suction without using a clamper or the like. [Explanation of symbols]

[0066] 10, 13-19 Bonding stage, 11 Surface, 12 Vacuum pipe, 20-22 Recess, 30, 41, 46, 47 Spiral groove, 31 Inner diameter wall, 32 Outer diameter wall, 33 Bottom surface, 34 Gap, 35 Air flow path, 42 Inner spiral groove, 43 Outer spiral groove, 51 First spiral groove, 52 Second spiral groove, 57 Branch groove, 61, 62 Radial groove, 65 Square spiral groove, 70 Wafer, 71 Outer periphery, 75 Semiconductor chip, 78 Substrate.

Claims

1. A bonding stage that vacuum-adsorbs a plate-shaped object onto its surface, a suction portion provided on the surface and configured to vacuum-suck a center portion of the object; a groove provided on the surface, communicating with the suction portion, extending from the suction portion toward the peripheral portion and suctioning the object from the center toward the outer periphery; A bonding stage characterized by:

2. 2. The bonding stage of claim 1, the groove is a spiral groove extending from the suction portion toward the peripheral portion; A bonding stage characterized by:

3. 3. The bonding stage according to claim 2, the cross-sectional area of ​​the spiral groove decreases toward the periphery; A bonding stage characterized by:

4. 4. The bonding stage according to claim 2 or 3, a plurality of branch grooves arranged between two adjacent arc portions of the spiral groove in the radial direction and branching radially inward from the arc portion on the outer side in the radial direction; A bonding stage characterized by:

5. 4. The bonding stage according to claim 2 or 3, the spiral groove is a plurality of spiral grooves, the plurality of spiral grooves communicate with different positions of the suction portion and extend parallel to one another from the suction portion toward the peripheral portion; A bonding stage characterized by:

6. 4. The bonding stage according to claim 2 or 3, The spiral groove has a cross-sectional area of ​​0.2 mm ２ The width is greater than the depth, and the depth is 0.1 mm or more. A bonding stage characterized by:

7. 6. The bonding stage according to claim 5, The plurality of spiral grooves have a cross-sectional area of ​​0.2 mm ２ The width is greater than the depth, and the depth is 0.1 mm or more. A bonding stage characterized by:

8. 4. The bonding stage according to claim 2 or 3, the spiral groove is a square spiral groove; A bonding stage characterized by:

9. 2. The bonding stage of claim 1, a plurality of the adsorption portions are provided on the surface, the grooves are a plurality of spiral grooves having different widths, the plurality of spiral grooves communicate with different suction portions and extend parallel to one another from the suction portions toward the peripheral portion; A bonding stage characterized by:

10. 10. The bonding stage of claim 9, the plurality of spiral grooves have cross-sectional areas that decrease toward the periphery; A bonding stage characterized by:

11. 11. The bonding stage according to claim 9 or 10, The plurality of spiral grooves have a cross-sectional area of ​​0.2 mm ２ The width is greater than the depth, and the depth is 0.1 mm or more. A bonding stage characterized by:

12. 2. The bonding stage of claim 1, the grooves are a plurality of radial grooves extending radially from the suction portion toward the peripheral portion; A bonding stage characterized by:

13. 13. The bonding stage of claim 12, the plurality of radial grooves have cross-sectional areas that become smaller toward the periphery; A bonding stage characterized by:

14. 14. The bonding stage according to claim 12 or 13, The width of the radial grooves is 0.05 to 0.1 mm; A bonding stage characterized by:

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