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] This invention relates to the structure of a bonding stage. [Background technology]

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

[0003] [Patent Document 1] Japanese Patent Publication No. 2013-179207 [Overview of the project] [Problems that the invention aims to solve]

[0004] Incidentally, a bonding method is used in which semiconductor chips are mounted in multiple layers on the surface of a wafer. In this case, when the first layer of semiconductor chips 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 layer of semiconductor chips, it was necessary to use a clamp to press the warped wafer against the surface of the bonding stage, make the warped wafer conform to the surface of the bonding stage, and then vacuum-adsorb the wafer onto the surface of the bonding stage. This resulted in a complex structure for the bonding stage and a time-consuming setup process for vacuum adsorption of the wafer.

[0005] Therefore, the present disclosure aims to vacuum-adsorb a warped wafer by conforming it to the surface of a bonding stage using a simple configuration. [Means for solving the problem]

[0006] The bonding stage of this disclosure is a bonding stage for vacuum adsorption of a plate-shaped object onto its surface, comprising: an adsorption portion provided on the surface for vacuum adsorption of the central part of the object; and a groove provided on the surface, communicating with the adsorption portion, extending from the adsorption portion toward the periphery, for adsorption of the object from the center toward the outer periphery. The groove is a helical groove extending from the adsorption portion toward the peripheral portion, and the helical groove has a cross-sectional area of ​​0.2 mm². 2 Below, the ratio of width to depth is 3 to 10, and the depth is 0.1 mm or more. It is characterized by the following:

[0007] As a result, the bonding stage of this disclosure can bond a curved plate-shaped object using only vacuum suction without the use of clamps or the like. disc-shaped wafer Evenly distribute the bonding stage It can be vacuum-adsorbed by conforming to the surface. Furthermore, by increasing the airflow velocity within the helical groove, the vacuum level of the helical groove can be raised to a level sufficient to adsorb a warped wafer.

[0010] In the bonding stage of this disclosure, the cross-sectional area of ​​the helical groove may decrease towards the periphery.

[0011] As the cross-sectional area of ​​the helical groove decreases, the airflow velocity within the groove increases, resulting in a higher vacuum level. Therefore, a smaller cross-sectional area of ​​the helical groove allows for greater vacuum adhesion of the wafer's warped portion to the bonding stage surface. Consequently, by reducing the cross-sectional area of ​​the helical groove towards the periphery, the outer periphery of a warped wafer with significant upward deformation can be conformed to the bonding stage surface and vacuum-adhered. Furthermore, by increasing the cross-sectional area of ​​the groove in the central part compared to the periphery, the air resistance of the helical groove is reduced, increasing the amount of air drawn in, and allowing the warped wafer to be vacuum-adhered to the bonding stage surface in a shorter time.

[0012] In the bonding stage of the present disclosure, a plurality of branch grooves may be provided between two arc portions adjacent in the radial direction of the spiral groove, and the branch grooves branch from the radially outer arc portion toward the radially inner side.

[0013] Thereby, the adsorption force of the bonding stage can be increased.

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

[0015] Thereby, the adsorption force of the bonding stage can be increased.

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

[0019] Thereby, a warped square substrate can be made to conform to the surface of the bonding stage and vacuum-adsorbed.

[0020] In the bonding stage of the present disclosure, a plurality of 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 adsorption portions, and extend parallel to each other from each adsorption portion toward the peripheral portion.

[0021] Thereby, the cross-sectional area of the spiral groove to be used can be selected according to the magnitude of the warp of the warped wafer. For example, in the case of a wafer with a large warp, a spiral groove with a small cross-sectional area can be used to gradually make the wafer conform to the surface of the bonding stage, and in the case of a wafer with a small warp, a spiral groove with a large cross-sectional area can be used to make the wafer conform to the surface of the bonding stage in a short time.

[0022] In the bonding stage of the present disclosure, the plurality of spiral grooves may have a smaller cross-sectional area toward the peripheral portion.

[0023] As a result, the outer peripheral portion of the warped wafer with a large amount of upward deformation can be vacuum-sucked following the surface of the bonding stage. Further, as a result, the air resistance of the spiral groove is reduced to increase the amount of sucked air, and the warped wafer can be vacuum-sucked onto the surface of the bonding stage in a short time.

Effect of the Invention

[0028] The present disclosure can vacuum-suck a warped wafer following the surface of a bonding stage with a simple configuration.

Brief Description of the Drawings

[0029] [Figure 1] It is a perspective view showing the bonding stage of an embodiment. [Figure 2] It is a plan view of the bonding stage shown in FIG. 1. [Figure 3] It is a cross-sectional view of the state where the central portion of the wafer is vacuum-sucked on the surface of the bonding stage shown in FIG. 2, and is the A-A cross-section shown in FIG. 2. [Figure 4] It is a cross-sectional view of the state where the central portion of the wafer is vacuum-sucked on the surface of the bonding stage shown in FIG. 2, and is the B-B cross-section shown in FIG. 2. [Figure 5] It is a cross-sectional view of the bonding stage and the wafer showing the initial state where the warped wafer is placed on the surface of the bonding stage, and is the C-C cross-section shown in FIG. 2. [Figure 6] It is a cross-sectional view showing the change in the shape of the wafer in the state where from the concave portion to the second turn of the spiral groove becomes vacuum after the state shown in FIG. 5. [Figure 7] It is a cross-sectional view showing the state where after the state shown in FIG. 6, the entire spiral groove becomes vacuum and the entire wafer is vacuum-sucked following the surface of the bonding stage. [Figure 8] It is a plan view showing the bonding stage of another embodiment. [Figure 9] It is a plan view showing the bonding stage of another embodiment. [Figure 10]This is a plan view showing a bonding stage of another embodiment. [Figure 11] This is a plan view showing a bonding stage of another embodiment. [Figure 12] This is a plan view showing a bonding stage as an example. [Figure 13] This is a plan view showing a bonding stage as an example. [Figure 14] This is a plan view showing a bonding stage of another embodiment. [Modes for carrying out the invention]

[0030] The bonding stage 10 of the embodiment will be described below with reference to the drawings. As shown in Figure 1, the bonding stage 10 is a rectangular flat plate member, and a recess 20 and a helical groove 30 are provided on its surface 11. The recess 20 is located in the center of the bonding stage 10. A vacuum pipe 12 connected to a vacuum device is connected to the bottom of the recess 20. The helical groove 30 communicates with the side surface of the recess 20 and extends from the center to the periphery of the bonding stage 10. As shown in Figure 2, the shape of the helical groove 30 may be, for example, an Archimedean 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 vacuumed using a vacuum device, the helical groove 30 communicating with the recess 20 also becomes vacuumed. As a result, the disc-shaped wafer 70 is vacuum-adsorbed onto the surface 11 of the bonding stage 10. At this time, the center of the wafer 70 is vacuum-adsorbed to the center of the bonding stage 10. The outer periphery of the wafer 70 is vacuum-adsorbed to the periphery of the bonding stage 10. The dashed circle in Figure 1 indicates the outer edge 71 of the area on which the wafer 70 is placed. Therefore, the wafer 70 is a plate-shaped object that the bonding stage 10 vacuum-adsorbs. The recess 20 constitutes the adsorption part that vacuum-adsorbs the wafer 70.

[0032] As shown in Figures 3 and 4, the helical groove 30 comprises an inner diameter wall 31, an outer diameter wall 32, and a bottom surface 33. The depth of the helical groove 30 is D, and its width is W. The details of the shape of the helical groove 30 will be described later.

[0033] The recess 20 only needs to be large enough to vacuum-adhere 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 helical groove 30, or it may be deeper. For example, the depth may be 0.1 mm to 0.2 mm.

[0034] Next, the principle and operation of vacuum adsorption of the warped wafer 70 will be explained with reference to Figures 2 to 7. Figures 5 to 7 are cross-sectional views showing the pressure in the helical groove 30 and the change in the shape of the wafer 70 when the warped wafer 70 is vacuum-adsorbed to the surface 11 of the bonding stage 10. In Figures 5 to 7, the shaded recesses 20 and helical grooves 30 indicate the recesses 20 and helical grooves 30 under vacuum.

[0035] When a semiconductor chip 75 is bonded to the surface of a wafer 70, the difference in thermal expansion between the wafer 70 and the semiconductor chip 75 causes the wafer 70 to warp. As shown in Figure 5, the wafer 70 to which the semiconductor chip 75 is bonded warps and deforms into a dish shape, with the outer edge curving upwards.

[0036] As shown in Figure 5, the recess 20 located in the center of the bonding stage 10 is evacuated, and the center of the warped wafer 70 is placed on top of the recess 20. The center of the wafer 70 is then vacuum-adhered to the recess 20. When the surface 11 of the helical groove 30 communicating with the recess 20 is blocked by the wafer 70, a rectangular air channel 35 is formed at the position indicated by line 91 in Figure 2, as shown in Figure 3. Air then flows through the air channel 35 towards the recess 20. The symbol with an X inside a circle in Figure 3 indicates that the air is flowing from the front to the back of the page. At this time, the flow velocity of the air flowing through the air channel 35 is V1.

[0037] On the other hand, at the position indicated by line 92 in Figure 2, which is slightly away from the recess 20, the warped wafer 70 has not yet been vacuum-adsorbed, as shown in Figure 4. At this position, as indicated by the white arrow in Figure 4, air is drawn in from the gap 34 between the wafer 70 and the surface 11 of the bonding stage 10 toward the helical groove 30. At this time, the flow velocity of the air flowing through the gap 34 is V2. The air that has flowed into the helical groove 30 then flows into the recess 20 through the square air channel 35 shown in Figure 3. Note that the symbol with an X inside a circle in Figure 4 indicates that the air is flowing from the front to the back of the paper. At this time, the flow velocity of the air in the helical groove 30 is V3. As a result, the pressure in the gap 34 and the helical groove 30 shown in Figure 4 decreases. When the air flow velocities V2 and V3 are sufficiently fast, the vacuum level in the gap 34 and the helical groove 30 increases, and the warped wafer 70 is vacuum-adsorbed to the surface 11.

[0038] In this way, when the wafer 70 is vacuum-adsorbed to the helical groove 30, the wafer 70 and the helical groove 30 form a rectangular air channel 35 at the position of line 92 in Figure 2. The air channel 35 draws in air from the gap 34 and the helical groove 30 on the outer periphery of the position of line 92 in Figure 2, creating a vacuum in the gap 34 and the helical groove 30 in that region. As a result, the wafer 70 on the outer periphery of the position of line 92 in Figure 2 is vacuum-adsorbed. In this way, the helical groove 30 becomes vacuum-adsorbed sequentially from the center to the periphery. As shown in Figure 6, when the area from the recess 20 to the second turn of the helical groove 30 becomes vacuum-adsorbed, the portion of the wafer 70 located from the center to the second turn of the helical groove 30 is vacuum-adsorbed to the surface 11. Then, when the entire helical groove 30 becomes vacuum-adsorbed, as shown in Figure 7, the entire curved wafer 70 is vacuum-adsorbed, conforming to the surface 11 of the bonding stage 10. In this way, the bonding stage 10 gradually conforms the warped wafer 70 to the surface 11 from the center outwards and uses vacuum adsorption.

[0039] Here, we will explain the shape of the helical groove 30 necessary for gradually vacuum-adhering the warped wafer 70 from the center to the outer edge, as described above. As explained earlier with reference to Figures 3 and 4, in order to vacuum-adhere the wafer 70 to the helical groove 30, the air flow velocity V3 in the helical groove 30 must be sufficiently fast. To achieve this, the cross-sectional area of ​​the helical groove 30 must be reduced. On the other hand, if the air resistance of the air channel 35 (see Figure 3) composed of the helical groove 30 and the wafer 70 becomes large, the air flow rate will decrease, and the air flow velocity V3 will decrease. To reduce the resistance of the air channel 35, the wetted surface area of ​​the air channel 35 must be reduced.

[0040] According to the inventors' test research, the cross-sectional area of ​​the helical groove 30 is 0.2 mm 2 It was found that by doing the following, it is possible to adsorb a warped wafer 70 and reduce the resistance of the air channel 35. The cross-sectional area of ​​the helical groove 30 is 0.2 mm². 2 The shape of the helical groove 30 can be freely set as follows, but it is preferable that the width W is greater than the depth D, and the depth D is 0.1 mm or more. This is because if the depth D of the helical groove 30 is less than 0.1 mm, the resistance of the air passage 35 will be high, which may prevent adsorption to the outer edge 71, or it may take a long time for adsorption to occur. More preferably, the ratio of the width W to the depth D of the helical groove 30 may be 3 to 10, where W = (3 to 10) × D, and the depth D may be in the range of 0.1 mm to 0.2 mm. Here is an example of the cross-sectional shape of the helical 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 helical groove 30 is 0.03 mm². 2 ~0.1mm 2 This is the result. Also, if 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 helical groove 30 is 0.12 mm². 2 ~0.2mm 2 This is the result. Furthermore, the cross-sectional area of ​​the helical groove 30 may be appropriately changed depending on the vacuum flow path and the exhaust capacity of the vacuum pump. For example, if the exhaust capacity of the vacuum pump is large, the cross-sectional area can be set to 0.2 mm². 2 It can be made larger than that.

[0041] As explained above, the bonding stage 10 can vacuum-adhere a warped wafer 70 to conform to the surface 11 of the bonding stage 10 using only vacuum suction, without the use of clamps or the like.

[0042] Next, a bonding stage 13 of another embodiment will be described with reference to Figure 8. Parts similar to those of the bonding stage 10 described earlier with reference to Figures 1 to 7 are denoted by the same reference numerals and their descriptions are omitted.

[0043] The bonding stage 13 shown in Figure 8 is equipped with a helical groove 41 consisting of an outer helical groove 43 in the peripheral area and an inner helical groove 42 in the central area. The depth D of the outer helical groove 43 and the inner helical groove 42 are the same, the width W3 of the outer helical groove 43 is narrower than the width W2 of the inner helical groove 42, and the cross-sectional area of ​​the outer helical groove 43 is smaller than the cross-sectional area of ​​the inner helical groove 42.

[0044] As explained earlier with reference to Figure 5, the amount of upward deformation of a warped wafer 70 increases towards the outer edge. On the other hand, as explained earlier, the vacuum level within the helical groove 30 tends to increase as the cross-sectional area decreases. Therefore, the smaller the cross-sectional area of ​​the helical groove 30, the more the warped portion of the wafer 70 can be vacuum-adsorbed to the surface 11 of the bonding stage 13. Furthermore, to vacuum-adsorb the vicinity of the center of a wafer 70 with little warping, the cross-sectional area does not need to be large. Increasing the cross-sectional area reduces the air resistance of the air flowing through the air channel 35 (see Figure 3), thereby increasing the airflow rate in the helical groove 30.

[0045] Therefore, in the bonding stage 13, the depth D is made constant, and the width W3 of the outer spiral groove 43 is made narrower than the width W2 of the inner spiral groove 42. As a result, the outer peripheral portion of the warped wafer 70 with a large amount of upward deformation can be vacuum-sucked following the surface 11 of the bonding stage 13, and the resistance of the air flow path 35 can be reduced to increase the amount of sucked air. Thereby, the warped wafer 70 can be vacuum-sucked onto the surface 11 of the bonding stage 13 in a shorter time compared to the bonding stage 10. Here, the cross-sectional shapes of the outer spiral groove 43 and the inner spiral groove 42 are, as described above, the cross-sectional area is 0.2 mm 2 Hereinafter, the ratio of the widths W2 and W3 to the depth D is set in the range of 3 to 10, and the depth D is in the range of 0.1 mm to 0.2 mm.

[0046] The bonding stage 13 shown in FIG. 8 has been described assuming that it includes the outer spiral groove 43 and the inner spiral groove 42, but it is not limited thereto. For example, the width W or the cross-sectional area of one spiral groove 30 may be configured to continuously decrease toward the peripheral portion.

[0047] Next, the bonding stage 14 of another embodiment will be described with reference to FIG. 9. The same parts as those of the bonding stage 10 described above with reference to FIGS. 1 to 7 are denoted by the same reference numerals, and the description thereof will be omitted.

[0048] As shown in FIG. 9, the bonding stage 14 is formed by connecting two spiral grooves 46 and 47 of the same shape in one recess 20. The two spiral grooves 46 and 47 communicate with different positions of the recess 20 and extend parallel to each other from the central portion toward the peripheral portion. The recess 20 is not limited to a single hole and may have any shape that can suck the wafer 70, for example, a shape having a plurality of holes on the surface 11, a mesh shape, or a porous shape.

[0049] In this way, by arranging the two helical grooves 46 and 47, the suction force of the bonding stage 14 can be made greater than that of the bonding stage 10. As a result, the bonding stage 14 can vacuum-adhere a wafer 70 with a large degree of warpage, conforming it to the surface 11 of the bonding stage 14.

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

[0051] Next, a bonding stage 15 of another embodiment will be described with reference to Figure 10. Parts similar to those of the bonding stage 10 described earlier with reference to Figures 1 to 7 are denoted by the same reference numerals and their descriptions are omitted.

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

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

[0054] Here, the amount of warping of the wafer 70 increases as the number of layers of semiconductor chips 75 bonded onto the wafer 70 increases. Therefore, the amount of warping of the wafer 70 will differ depending on the number of layers of bonded semiconductor chips 75.

[0055] In the bonding stage 15, when vacuum-adsorbing a wafer 70 with a large amount of warpage, the recess 21 is connected to a vacuum device to create a vacuum in the first helical groove 51, allowing the wafer 70 to be vacuum-adsorbed onto the surface 11 over time. On the other hand, when vacuum-adsorbing a wafer 70 with a small amount of warpage, the recess 22 is connected to a vacuum device to create a vacuum in the second helical groove 52, allowing the wafer 70 to be vacuum-adsorbed onto the surface 11 in a short time. As a result, the bonding stage 15 can efficiently vacuum-adsorb wafers 70 with different amounts of warpage onto the surface 11.

[0056] Next, a bonding stage 16 of another embodiment will be described with reference to Figure 11. Parts similar to those of the bonding stage 10 described earlier with reference to Figures 1 to 7 are denoted by the same reference numerals and their descriptions are omitted.

[0057] As shown in Figure 11, the bonding stage 16 includes a helical groove 30 and a plurality of branch grooves 57 that branch off from the helical groove 30. The branch grooves 57 are positioned between two radially adjacent arc portions of the helical groove 30 and include a plurality of branch grooves 57 that branch radially inward from the radially outer arc portion. The cross-sectional area of ​​the branch grooves 57 may be the same as that of the helical groove 30, or it may be smaller than that of the helical groove 30. For example, the depth D and width W may be the same as those of the helical groove 30, or the depth D may be the same as that of the helical groove 30 and the width W may be narrower than that of the helical groove 30. As a result, the bonding stage 16 can have a greater adsorption force than the bonding stage 10 described earlier.

[0058] Next, referring to Figure 12 Reference exampleThe bonding stage 17 will now be described. The bonding stage 17 is a modified version of the bonding stage 10, described with reference to Figures 1 to 7, where the helical grooves 30 are replaced with radial grooves 61. The radial grooves 61 extend linearly from the center to the periphery, and their length is shorter than that of the helical grooves 30. Furthermore, the bonding stage 17 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 helical grooves 30 described earlier. This allows the cross-sectional area of ​​each radial groove 61 to be smaller than that of the helical grooves 30. For example, the width W7 of the radial grooves 61 can be narrower than the width W of the helical grooves 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 that of the helical grooves 30. In this case, the cross-sectional area of ​​the radial grooves 61 is 0.005 mm². 2 ~0.01mm 2 This falls within the specified range. Furthermore, the depth D may be greater than 0.1 mm, for example, 0.2 mm.

[0059] Thus, the total cross-sectional area of ​​the radial grooves 61 is larger than the cross-sectional area of ​​the helical grooves 30, and their length is shorter, resulting in a larger volume of air being drawn into the recesses 20. For this reason, the bonding stage 17 can quickly align the warped wafer 70 to the surface 11 and vacuum-adsorb it, compared to the bonding stage 10. Even if the total cross-sectional area of ​​the radial grooves 61 is equal to the cross-sectional area of ​​the helical grooves 30, the length of the radial grooves 61 is shorter than the length of the helical grooves 30, resulting in a larger volume of air being drawn into the recesses 20. Therefore, in this case as well, the bonding stage 17 can quickly align the wafer 70 to the surface 11 and vacuum-adsorb it.

[0060] Next, referring to Figure 13 Reference example The bonding stage 18 will now be described. The bonding stage 18 is a bonding stage 17 in which the radial grooves 61 are replaced with radial grooves 62 that become narrower towards the periphery. The width W8 of the radial grooves 62 may be, for example, about 0.1 mm in the center and about 0.05 mm at 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 in the center. 2, 0.005 mm at the periphery 2 This is the result.

[0061] The bonding stage 18 can vacuum-adsorb the outer edge of a warped wafer 70, which has a large amount of upward deformation, by conforming it to the surface 11.

[0062] Next, another embodiment, the bonding stage 19, will be described with reference to Figure 14. Parts similar to those described earlier with reference to Figures 1 to 7 of the bonding stage 10 are denoted by the same reference numerals and their descriptions are omitted.

[0063] Bonding stage 19 is a bonding stage 10 described with reference to Figures 1 to 7, in which the helical groove 30 is replaced with a square helical groove 65. The depth D and width W are the same as those of the helical groove 30. Also, as described with reference to Figure 8, the cross-sectional area of ​​the outer part of the square helical groove 65 may be made smaller and the cross-sectional area of ​​the inner part of the square helical groove 65 may be made larger. Alternatively, the cross-sectional area of ​​the square helical groove 65 may be made continuously narrower towards the periphery. For example, the depth D may be kept constant, the width of the outer part of the square helical groove 65 may be made narrower and the width of the inner part of the square helical groove 65 may be made wider. Also, as described with reference to Figure 9, multiple square helical grooves 65 may be connected to a single recess 20. Furthermore, as described with reference to Figure 10, two square helical grooves 65 may be connected to two recesses 21 and 22.

[0064] The bonding stage 19 can vacuum-adsorb a curved rectangular substrate 78 by conforming it to the surface 11. Here, the rectangular substrate 78 is a plate-shaped object that the bonding stage 19 vacuum-adsorbs.

[0065] As described above, the bonding stages 10, 13-19 of the embodiment can vacuum-adhere a warped wafer 70 to conform to the surface 11 using only vacuum suction, without the use of clamps or the like. [Explanation of Symbols]

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

Claims

1. A bonding stage for vacuum adsorption of a plate-shaped object onto its surface, A suction part provided on the surface for vacuum adsorption of the central part of the object, The surface is provided with grooves that communicate with the adsorption portion and extend from the adsorption portion toward the peripheral portion, adsorbing the object toward the outer periphery from the central portion, The groove is a helical groove extending from the adsorption portion toward the peripheral portion, The aforementioned helical groove has a cross-sectional area of ​​0.2 mm² or less, a width-to-depth ratio of 3 to 10, and a depth of 0.1 mm or more. A bonding stage characterized by the following features.

2. A bonding stage according to claim 1, The helical groove has a smaller cross-sectional area towards the periphery. A bonding stage characterized by the following features.

3. A bonding stage according to claim 1 or 2, The helical groove is provided with a plurality of branch grooves arranged between two radially adjacent arc portions, and branching radially inward from the radially outer arc portion. A bonding stage characterized by the following features.

4. A bonding stage according to claim 1 or 2, The aforementioned helical groove is a plurality of helical grooves, The plurality of helical grooves communicate with different positions of the adsorption portion and extend parallel to each other from the adsorption portion toward the peripheral portion. A bonding stage characterized by the following features.

5. A bonding stage according to claim 1 or 2, The aforementioned spiral groove is a square spiral groove. A bonding stage characterized by the following features.

6. A bonding stage according to claim 1, Multiple adsorption portions are provided on the surface, The grooves are a plurality of helical grooves of different widths, The plurality of helical grooves communicate with different adsorption portions and extend parallel to each other from each adsorption portion toward the peripheral portion. A bonding stage characterized by the following features.

7. A bonding stage according to claim 6, The cross-sectional area of ​​the plurality of helical grooves decreases towards the periphery. A bonding stage characterized by the following features.

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