Holding table, processing apparatus, processing method, and method for manufacturing chips

Abstract

This aims to prevent deterioration of processing quality for the workpiece on the holding surface of the holding table, while simultaneously extending the lifespan of the outer periphery of the holding table. [Solution] The holding table (10) has a holding surface (14) for holding the object to be processed (1), and the holding surface includes an outer peripheral portion (20) in which a first member (18) that contacts the object to be processed and a second member (19) that supports the first member are laminated, and the hardness of the second member is higher than that of the first member.

Description

[Technical Field]

[0001] The present invention relates to a holding table, a processing apparatus and a processing method for processing a workpiece, and a method for manufacturing a chip. [Background Art]

[0002] When processing a workpiece held on a holding table, a suction force is applied to the holding surface of the holding table to suck and hold the workpiece on the holding surface, whereby the workpiece is shaped to conform to the holding surface. When holding a warped workpiece such as a package substrate, there has been a problem that suction force leaks at the warped portion of the workpiece, and the workpiece does not adhere closely to the holding surface.

[0003] As a countermeasure against such a problem, a method is known in which an annular elastic member is disposed on an outer peripheral portion of the holding surface of the holding table, and the workpiece is pressed against the holding surface to deform the elastic member, thereby preventing leakage of suction force and enabling holding of the workpiece (for example, Patent Documents 1 and 2). [Prior Art Document] [Patent Document]

[0004] [Patent Document 1] Japanese Patent Laid-Open No. 2014-072510 [Patent Document 2] Japanese Patent Laid-Open No. 2024-101611 [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] Conventionally, a single type of rubber sponge was used as the elastic member provided on the outer periphery of the holding surface of the holding table. However, if the hardness of the elastic member is too high (too hard), the warped workpiece cannot conform sufficiently to the elastic member, resulting in the workpiece being held in a distorted state. When grinding is performed on the workpiece in this state, high processing accuracy cannot be obtained, and in some cases, the outer periphery of the workpiece may be excessively ground.

[0006] Furthermore, if the hardness of the elastic member is low (too soft), it is easier to make the warped object being processed adhere closely to the elastic member, but this can easily cause permanent strain in the elastic member, preventing it from recovering from its deformed state, resulting in a short lifespan for the elastic member.

[0007] Thus, the countermeasure of providing a single type of rubber sponge on the outer circumference of the holding surface of the holding table risked compromising either the processing quality of the processed material or the lifespan of the elastic member.

[0008] The present invention aims to provide a holding table that prevents deterioration of processing quality for the object to be processed and extends the lifespan of the outer periphery of the holding table, a processing apparatus and processing method for processing the object to be processed, and a method for manufacturing chips. [Means for solving the problem]

[0009] One aspect of the present disclosure is a holding table having a holding surface for holding an object to be processed, wherein the holding surface includes an outer periphery in which a first member that contacts the object to be processed and a second member that supports the first member are laminated, and the hardness of the second member is higher than that of the first member.

[0010] The first member and the second member are preferably elastic members.

[0011] One aspect of the present disclosure is a processing apparatus comprising a holding table having the first member and the second member on its outer periphery, and a processing unit for processing an object to be processed held on the holding surface of the holding table.

[0012] One aspect of the present disclosure is a processing method for processing an object to be processed held on a holding table, wherein the holding surface of the holding table includes an outer periphery in which a first member that contacts the object to be processed and a second member that supports the first member are laminated, the hardness of the second member being higher than that of the first member, and the method comprises a holding step of holding the object to be processed on the holding surface, and a processing step of processing the object to be processed after the holding step.

[0013] One aspect of the present disclosure is a method for manufacturing a chip from a workpiece held on a holding table, wherein the holding surface of the holding table includes an outer periphery in which a first member that contacts the workpiece and a second member that supports the first member are laminated, the hardness of the second member being higher than that of the first member, and the method comprises a holding step of holding the workpiece on the holding surface, a grinding step of grinding the workpiece held on the holding surface, and a dividing step of dividing the workpiece to manufacture a plurality of chips. [Effects of the Invention]

[0014] According to each of the above embodiments, when processing an object to be processed while it is held on the holding surface of the holding table, it is possible to prevent deterioration of the processing quality of the object to be processed and to extend the lifespan of the outer periphery of the holding table. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view showing the configuration of the holding table of the first embodiment. [Figure 2] This is a cross-sectional view showing the state in which the object to be processed is being held in the holding table of the first embodiment. [Figure 3] This is a cross-sectional view showing the state in which the object to be processed is held by the holding table of the first embodiment. [Figure 4] This is a cross-sectional view showing the configuration of the holding table in the second embodiment. [Figure 5]It is a cross-sectional view showing a grinding step of grinding a workpiece held on a holding table according to the second embodiment. [Figure 6] It is a cross-sectional view showing a dividing step of dividing a workpiece after grinding. [Figure 7] It is a cross-sectional view showing a dividing step of dividing a workpiece held on a holding table according to the first embodiment. MODE FOR CARRYING OUT THE INVENTION

[0016] It is desirable that the holding table of each embodiment described below has a holding surface having a shape corresponding to the shape of the workpiece in a plan view. For example, when the workpiece is rectangular in plan view, it is desirable that the holding surface of the holding table is a rectangle similar in shape to the workpiece. When the workpiece is circular in plan view, it is desirable that the holding surface of the holding table is circular. In an existing holding table having a general structure, even if the holding surface has a shape different from that of the workpiece, the workpiece can be held as long as the holding surface is larger than the workpiece. In contrast, as will be described later, the holding table of the present disclosure holds the workpiece by bringing it into contact with a first member provided on an outer peripheral portion of the holding surface. Therefore, this is because it is preferable that the shape of the outer peripheral portion of the holding table including the first member and the shape of the workpiece match to a certain extent. However, the technology of the present disclosure is not limited to a configuration in which the shape of the workpiece completely matches the shape of the holding surface of the holding table, and it is only required that the outer peripheral portion of the holding surface has a relationship capable of holding a workpiece having a warped shape.

[0017] Note that the outer periphery of a workpiece or a holding table referred to in the present specification does not mean only a portion along the outer edge (periphery) when the outer shape of the workpiece or holding table is circular, but is a concept including a portion along the outer edge (periphery) when the outer shape of the workpiece or holding table has a shape other than circular (e.g., a rectangle or the like). Therefore, the outer periphery (outer peripheral portion) in the present specification may be read as an outer region (outer portion) relative to the center (central portion) in a broad concept.

[0018] Referring to FIGS. 1 to 3, the holding table 10 of the first embodiment will be described. The holding table 10 is for holding a workpiece 1. As shown in FIG. 1, the workpiece 1 has an upward warp 2 on its outer peripheral portion in a state before being held by the holding table 10. The Z-axis direction shown in each drawing is the vertical direction of a processing apparatus provided with the holding table 10, and is also the thickness direction of the workpiece 1 when held on the holding table 10.

[0019] The holding table 10 includes a frame body 11 having a central recess 12 on an upper surface side, and a porous member 13 attached in the central recess 12. An upper surface 111 of the frame body 11 and an upper surface 131 of the porous member 13 are continuous in a flush relationship with no step between each other, and a holding surface 14 of the holding table 10 is constituted by the upper surface 111 and the upper surface 131.

[0020] The holding table 10 includes a flow path 15 connected to a bottom of the central recess 12, and the flow path 15 is connected to a suction source 16. When the suction source 16 performs a suction operation, air in the porous member 13 is sucked through the flow path 15, and negative pressure acts on the upper surface 131.

[0021] On the upper surface 111 of the frame body 11, an outer peripheral recess 17 is provided which is arranged to surround an outer side of the central recess 12. A first member 18 and a second member 19 that constitute an outer peripheral holding portion 20 which is an outer peripheral portion of the holding table 10 have a shape along the outer peripheral recess 17, and are provided over the entire outer periphery of the holding table 10 without being interrupted in the middle. The outer peripheral holding portion 20 is supported by the outer peripheral recess 17 in a state where the first member 18 is laminated on an upper side and the second member 19 is laminated on a lower side.

[0022] The first member 18 and the second member 19 are each made of a material having lower hardness than the frame body 11, and the first member 18 and the second member 19 can be deformed when a force of a predetermined magnitude or larger that presses the workpiece 1 toward the holding surface 14 side is applied. In addition, the first member 18 and the second member 19 are formed of a non-air-permeable material and structure.

[0023] The first member 18 and the second member 19 of this embodiment are elastic members that can be elastically deformed. For example, the first member 18 and the second member 19 are formed from materials such as natural rubber, ethylene-propylene-diene rubber (EPDM), ethylene-propylene rubber (EPM), silicone rubber, or synthetic resins such as polyolefin.

[0024] At least one of the first member 18 and the second member 19 may be formed of rubber or resin having air bubbles. As will be described later, the outer peripheral holding portion 20, which consists of the first member 18 and the second member 19, has the role of preventing leakage of suction force, so in this case, it is desirable that it be an independent-cell structure (non-permeable structure) in which adjacent air bubbles are not in communication with each other.

[0025] The hardness of the second member 19 is higher than that of the first member 18. For example, when rubber hardness is applied as the standard unit of hardness, the hardness of the first member 18 is preferably in the range of 5 to 20 degrees, and the hardness of the second member 19 is preferably in the range of 20 to 35 degrees. Furthermore, the difference in hardness between the first member 18 and the second member 19 is preferably 5 degrees or more and 30 degrees or less.

[0026] The lower surface of the first member 18 and the upper surface of the second member 19, which are stacked vertically, are joined by a predetermined joining means. As a joining means, for example, adhesive bonding or direct bonding by thermocompression bonding can be applied. The joining means is selected to be optimal according to the respective materials of the first member 18 and the second member 19, so as to obtain sufficient joining strength and to prevent problems such as chemical degradation of the first member 18 and the second member 19.

[0027] The outer peripheral holding portion 20 is attached to the frame 11 with the second member 19 inserted into the outer peripheral recess 17. In the configuration examples shown in Figures 1 to 3, the outer peripheral recess 17 has a rectangular cross-sectional shape that opens upward, and the second member 19 has a rectangular cross-sectional shape corresponding to the outer peripheral recess 17, so that the second member 19 fits snugly inside the outer peripheral recess 17 without any gaps. The second member 19 can be attached to the outer peripheral recess 17 by, for example, press-fitting, which involves compressing the second member 19 and pushing it into the outer peripheral recess 17.

[0028] Furthermore, the cross-sectional shape of the outer peripheral recess 17 and the second member 19 may not be the simple rectangular shape shown in Figures 1 to 3, but may have a retaining structure to prevent the second member 19 inserted into the outer peripheral recess 17 from coming out upward. For example, the outer peripheral recess 17 and the second member 19 may have a wedge-shaped cross-section that widens as it goes downwards.

[0029] Alternatively, the second member 19 may be fixed to the inner surface of the outer peripheral recess 17 using a fixing means such as an adhesive. However, as will be described later, the second member 19 deforms together with the first member 18 when the object to be processed 1 is held on the holding surface 14 of the holding table 10, so it is preferable to fix the second member 19 in a way that leaves room for deformation. For example, by bonding only the lower surface of the second member 19 to the bottom surface of the outer peripheral recess 17, it is possible to prevent the second member 19 from falling out of the outer peripheral recess 17 without hindering the overall deformation of the second member 19.

[0030] Figure 1 shows the holding table 10 equipped with an outer peripheral holding portion 20 (first member 18 and second member 19) in its initial state, before the object to be processed 1 is held on the holding surface 14. In the initial state, the thickness of the second member 19 in the Z-axis direction is approximately the same as the depth of the outer peripheral recess 17, and the second member 19 is positioned to fill the internal space of the outer peripheral recess 17. The first member 18, which is stacked on top of the second member 19, protrudes above the holding surface 14 (upper surface 111 of the frame 11) in the initial state. In other words, before the object to be processed 1 is held, the holding table 10 has the first member 18 protruding from the holding surface 14.

[0031] As shown in Figure 2, when the object to be processed 1 is placed on the holding surface 14 of the holding table 10, the object to be processed 1 is supported by the holding surface 14 (particularly the upper surface 131 of the porous member 13), except for the outer periphery with the curvature 2. The first member 18 of the outer periphery holding part 20 is positioned below the outer periphery with the curvature 2, and the outer periphery with the curvature 2 is in contact with the upper surface of the first member 18.

[0032] Here, when a predetermined load is applied to press the object to be processed 1 against the holding surface 14, the first member 18, which has lower hardness than the frame 11 and the second member 19, compresses and deforms in the Z-axis direction, and comes into close contact with the lower surface of the outer circumference with the curvature 2. The second member 19, which has higher hardness than the first member 18 and lower hardness than the frame 11, compresses and deforms in the Z-axis direction with a smaller amount of deformation than the first member 18 as the first member 18 deforms. As a result, the outer circumference holding portion 20 takes on a shape that conforms to the outer circumference with the curvature 2, with a part of the first member 18 entering the outer circumference recess 17 and the protruding region of the first member 18 that protrudes above the holding surface 14 (upper surface 111 of the frame 11).

[0033] When the suction source 16 performs a suction operation and applies a suction force to the upper surface 131 of the porous member 13, the lower surface of the central part of the object to be processed 1 is attracted to the upper surface 131. At this time, since the non-permeable first member 18 is shaped to closely conform to the outer circumference of the object to be processed 1, no leakage of suction force occurs between the outer circumference of the object to be processed 1 and the first member 18, and a force is also applied to the outer circumference of the object to be processed 1 that attracts it towards the holding surface 14. As a result, as shown in Figure 3, the outer circumference of the object to be processed 1 approaches a flat shape that eliminates the warp 2, and the first member 18 is further compressed and deformed in the Z-axis direction, so that the upper surface of the first member 18 and the holding surface 14 (upper surface 111 of the frame 11) become roughly flush. Then, almost the entirety of the first member 18 and the second member 19 that constitute the outer circumference holding part 20 are housed in the outer circumference recess 17.

[0034] As a result, the object to be processed 1, including its outer circumference which initially had curvature 2, is held stably against the holding surface 14 of the holding table 10 without any leakage of suction force. Furthermore, since the suction force acts on the outer circumference of the object to be processed 1 and the outer circumference holding portion 20 deforms in a direction that accommodates the outer circumference recess 17, the lifting of the outer circumference of the object to be processed 1 relative to the holding surface 14 is suppressed.

[0035] Even if, in the holding state shown in Figure 3, the upper surface of the first member 18 and the holding surface 14 are not perfectly flush, and the first member 18 protrudes slightly beyond the holding surface 14, the effects of preventing leakage of suction force and suppressing the lifting of the outer periphery of the object to be processed 1 can still be obtained.

[0036] Since both the first member 18 and the second member 19 are elastic members, when the suction is released and the holding of the object to be processed 1 is terminated, and the object to be processed 1 is separated from the holding surface 14, the deformation state of the first member 18 and the second member 19 is resolved, and they return to the initial shape shown in Figure 1. Therefore, the holding table 10 can be repeatedly used to hold multiple objects to be processed 1.

[0037] As described above, in the holding table 10, a first member 18 and a second member 19 of different hardness are stacked and arranged on the outer periphery to form an outer periphery holding portion 20, and the hardness of the second member 19 that supports the first member 18 is set higher than the hardness of the first member 18 that comes into contact with the object to be processed 1.

[0038] This configuration allows for close contact between the relatively soft first member 18 and the outer circumference of the object to be processed 1, which has a curvature 2, thereby enhancing the effect of preventing leakage of suction force between the outer circumference of the object to be processed 1 and the outer circumference holding part 20. Furthermore, because the first member 18 is not too hard and deforms appropriately under the force applied when holding the object to be processed 1, reducing the amount of protrusion from the holding surface 14, it is possible to prevent the outer circumference of the object to be processed 1 that is in contact with the first member 18 from lifting significantly away from the holding surface 14. In this way, by preventing leakage of suction force and stably and accurately holding the entire object to be processed 1 on the holding table 10, it is possible to prevent deterioration of processing quality during processing performed on the object to be processed 1 while it is held on the holding table 10 (such as processing of the object to be processed 1 as described later).

[0039] Furthermore, by supporting the outer peripheral support portion 20 on the frame 11 via the second member 19, which has a higher hardness than the first member 18, the outer peripheral support portion 20, with the second member 19 as its base, possesses appropriate flexibility to absorb the warping 2 of the object to be processed 1, while being less prone to excessive deformation. As a result, the outer peripheral support portion 20 is less likely to develop permanent strain that prevents it from recovering from its deformed state, thereby improving the durability of the outer peripheral support portion 20 and extending its lifespan. For example, experiments have shown that the outer peripheral support portion 20, which combines two types of elastic members with different hardnesses (first member 18 and second member 19), has a significantly longer lifespan compared to the case where the outer peripheral support portion is constructed using only an elastic member with lower hardness than the second member 19.

[0040] Furthermore, by supporting the frame 11 via the second member 19, which has relatively high hardness, the stability of the outer peripheral holding portion 20 relative to the frame 11 can be increased. For example, when the first member 18 undergoes compressive deformation in the Z-axis direction, it is possible to prevent buckling in a direction intersecting the Z-axis direction.

[0041] As described above, the holding table 10 of this embodiment has an outer peripheral holding portion 20 that combines the expansion and contraction force of the first member 18, which has relatively low hardness, and the restoring force of the second member 19, which has relatively high hardness, thereby achieving both the prevention of deterioration in processing quality for the object to be processed 1 and the extension of the lifespan of the outer peripheral portion (outer peripheral holding portion 20) of the holding table 10.

[0042] Next, with reference to Figure 4, the holding table 21 of the second embodiment will be described. In the holding table 21, parts that are common with the holding table 10 of the first embodiment described earlier are denoted by the same reference numerals as the corresponding parts of the holding table 10, and their description is omitted.

[0043] The holding table 21 is provided with an outer peripheral holding portion 24 on the outer periphery of the frame 11, which is composed of a first member 22 and a second member 23. The first member 22 and the second member 23 are provided along the entire outer periphery of the holding table 21 without interruption. The conditions for the material and hardness of the first member 22 and the second member 23 are the same as those described above for the first member 18 and the second member 19 in the holding table 10 of the first embodiment. In other words, both the first member 22 and the second member 23 are made of a non-permeable material. Furthermore, the first member 22 and the second member 23 are made of a material with lower hardness than the frame 11, and the hardness of the second member 23 is higher than that of the first member 22. Furthermore, both the first member 22 and the second member 23 are made of elastic material.

[0044] The frame 11 has a mounting portion 25 for positioning the outer peripheral holding portion 24. The mounting portion 25 is a notched shape that is open on both the upper surface and the outer peripheral surface of the frame 11. In other words, the frame 11 has a surrounding wall 26 that surrounds the central recess 12 for attaching the porous member 13, and the outside of the surrounding wall 26 is open as the mounting portion 25.

[0045] The first member 22 and the second member 23 are arranged to surround the outside of the surrounding wall 26. The second member 23 has a greater width outward from the surrounding wall 26 than the first member 22, and has an overhanging portion 231 that extends outward from the area supporting the first member 22. In other words, the outer peripheral holding portion 24, consisting of the first member 22 and the second member 23, has an L-shaped cross-section with the second member 23 as its lower side.

[0046] The second member 23 is attached to the mounting portion 25 via the mounting member 27. The mounting member 27 has an inverted L-shaped cross-section, including an upper wall portion 271 that covers the upper surface of the overhang portion 231, and a base portion 272 that extends downward from the outer edge of the upper wall portion 271 and is supported by the frame 11. The base portion 272 is fixed to the frame 11 by fixing bolts 28 that penetrate in the Z-axis direction. The outer peripheral holding portion 24 can be removed from the frame 11 by removing the fixing bolts 28 and releasing the hold of the mounting member 27.

[0047] The mounting member 27 may be provided along the entire outer circumference of the holding table 21, or it may be partially arranged at intervals along the outer circumference. At a minimum, it is sufficient that the second member 23 can be stably fixed to the mounting portion 25 via the mounting member 27 without falling off.

[0048] Figure 4 shows the holding table 21 equipped with the outer peripheral holding portion 24 (first member 22 and second member 23) in its initial state, without holding the object to be processed 1. In the initial state, the first member 22 protrudes above the holding surface 14 (upper surface 111 of the frame 11).

[0049] When the object to be processed 1 is placed on the holding surface 14 of the holding table 21, the first member 22 compressively deforms in the Z-axis direction and adheres closely to the lower surface of the outer circumference of the object to be processed 1, which has a curvature 2. When the suction operation by the suction source 16 is performed and a suction force is applied to the upper surface 131 of the porous member 13, no leakage of suction force occurs between the outer circumference of the object to be processed 1 and the first member 22, and a force is applied to the outer circumference of the object to be processed 1 that pulls it toward the holding surface 14. As a result, the outer circumference of the object to be processed 1 approaches a flat shape that eliminates the curvature 2, and the first member 22 compressively deforms in the Z-axis direction, so that the upper surface of the first member 22 and the holding surface 14 become almost flush. In this way, almost the entire object to be processed 1, including the outer circumference, is stably held toward the holding surface 14 of the holding table 21 without any leakage of suction force. When the first member 22 deforms, the second member 23, which receives force via the first member 22, also deforms. However, because the hardness of the second member 23 is relatively high, the amount of deformation of the second member 23 is smaller than the amount of deformation of the first member 22.

[0050] Furthermore, even if the porous member 13 is held on the holding surface 14 of the holding table 21, and the upper surface of the first member 22 and the holding surface 14 are not perfectly flush, and the first member 22 protrudes slightly beyond the holding surface 14, the effect of preventing leakage of suction force and the effect of suppressing the lifting of the outer periphery of the object to be processed 1 can still be obtained.

[0051] Since both the first member 22 and the second member 23 are elastic members, when the holding of the object to be processed 1 is terminated and the object to be processed 1 is separated from the holding surface 14, the deformation state of the first member 22 and the second member 23 is resolved, and they return to the initial shape shown in Figure 4.

[0052] The holding table 21 of the second embodiment, configured as described above, prevents leakage of suction force between the outer periphery of the object to be processed 1 and the outer periphery holding portion 24, and suppresses the lifting of the outer periphery of the object to be processed 1 from the holding surface 14. Therefore, it is possible to prevent deterioration of processing quality during processing performed on the object to be processed 1 while it is held on the holding table 21 (such as processing of the object to be processed 1 as described later). Furthermore, by supporting the first member 22 via the second member 23, which has a higher hardness than the first member 22, permanent deformation of the outer periphery holding portion 24 is less likely to occur, improving the durability of the outer periphery holding portion 24 and extending its lifespan. In other words, by providing an outer periphery holding portion 24 that combines the expansion and contraction force of the first member 22, which has relatively low hardness, and the restoring force of the second member 23, which has relatively high hardness, the same effects as the holding table 10 of the first embodiment described above can be obtained.

[0053] Furthermore, in the second embodiment, the holding table 21 securely prevents the outer peripheral holding portion 24 from falling off the frame 11 by attaching the second member 23 to the mounting portion 25 via the mounting member 27, allowing the outer peripheral holding portion 24 to be operated with excellent stability. In particular, since the object pressed by the mounting member 27 is the protruding portion 231 of the second member 23, which has a higher hardness than the first member 22, the stability of the support of the outer peripheral holding portion 24 to the frame 11 is excellent. As a result, buckling of the first member 22 is less likely to occur, the contact pressure of the first member 22 with respect to the outer peripheral portion of the object to be processed 1 can be maintained, and the occurrence of suction force leakage between the object to be processed 1 and the first member 22 can be reliably prevented.

[0054] Furthermore, by releasing the fixing bolt 28 and removing the mounting member 27, the outer peripheral holding part 24 can be easily removed from the frame 11, resulting in excellent workability when performing maintenance such as replacing the outer peripheral holding part 24 or cleaning the mounting part 25.

[0055] Next, we will describe the processing steps in which the object to be processed 1 is held by the holding tables 10 and 21 of each embodiment and the processing apparatus that performs the processing on the object to be processed 1. In the processing examples shown in Figures 5 to 7, a package substrate is used as the object to be processed 1. This package substrate is rectangular (square) in plan view, and a semiconductor device, a chip 3, is formed in each of the multiple device areas partitioned by grid-like division lines. A layer of molded resin is formed on the surface of the package substrate. In the manufacturing process of the package substrate, the molded resin is hardened by heating, but at that time, thermal stress causes warping of the substrate, resulting in a warped object to be processed 1 as shown in Figures 1 and 4. In the processing examples shown in Figures 5 to 7, the molded resin of such a package substrate, the object to be processed 1, is ground to flatten it, and the package substrate is divided along the division lines to produce multiple individual chips 3.

[0056] Figure 5 shows a grinding step in which the workpiece 1 is ground using a grinding device 30, as an example of a processing apparatus and processing steps. The grinding device 30 that performs the grinding process is equipped with the holding table 21 of the second embodiment described above. Before grinding, a holding step is performed in which the workpiece 1 is held on the holding surface 14 of the holding table 21.

[0057] The grinding device 30 is equipped with a table rotation mechanism 31 that rotates the holding table 21 around an axis in the Z-axis direction. The table rotation mechanism 31 includes a motor and a power transmission mechanism (not shown), and the driving force of the motor is transmitted to the holding table 21 by the power transmission mechanism, causing the holding table 21 to rotate.

[0058] During grinding with the grinding device 30, a protective member 4 is attached to the lower surface of the workpiece 1. In the holding step, where the workpiece 1 is held on the holding surface 14 of the holding table 21, the workpiece 1 is held by suction to the holding surface 14 via the protective member 4. The outer circumference of the protective member 4 is in close contact with the outer circumference holding portion 24 (first member 22) of the holding table 21, preventing leakage of suction force, and the workpiece 1 is held on the holding table 21 in a stable state, eliminating the effects of warping.

[0059] A grinding unit 32 is positioned above the holding table 21. The grinding unit 32 is an example of a processing unit that processes the workpiece 1 held on the holding table 21. The grinding unit 32 has a disc-shaped mount 34 at the lower end of a spindle 33, which is a rotating shaft extending in the Z-axis direction, and an annular grinding wheel 35 is mounted on the lower surface of the mount 34. Multiple grinding wheels 36, which are processing tools, are arranged in an annular pattern on the lower surface of the grinding wheel 35.

[0060] The spindle 33 rotates around its Z-axis axis via a spindle rotation mechanism 37. The spindle rotation mechanism 37 includes a bearing that rotatably supports the spindle 33 and a spindle motor that provides the driving force to rotate the spindle 33. When the spindle 33 is rotated by the spindle rotation mechanism 37, the grinding wheel 35 rotates, and the multiple grinding wheels 36 move in the rotational direction as the grinding wheel 35 rotates.

[0061] The grinding unit 32 is moved in the Z-axis direction by a lifting mechanism 38. The lifting mechanism 38 consists of a ball screw unit including a ball screw and a motor, an air cylinder unit, and the like.

[0062] When grinding the workpiece 1 with the grinding device 30, the workpiece 1 is held by suction on the holding surface 14 of the holding table 21 via a protective member 4, and the grinding unit 32 is positioned above the holding table 21. The table rotation mechanism 31 is operated to rotate the holding table 21 holding the workpiece 1. In the grinding unit 32, the spindle rotation mechanism 37 is operated to rotate the spindle 33, and the lifting mechanism 38 is operated to lower the grinding unit 32.

[0063] These actions cause the grinding wheel 36 and the workpiece 1 to rotate relative to each other, causing the grinding wheel 36 to contact the molded resin on the surface of the workpiece 1 and grind the molded resin. Once a predetermined amount of grinding is complete, the lifting mechanism 38 is operated to raise the grinding unit 32, separating the grinding wheel 36 from the workpiece 1.

[0064] Since the workpiece 1 is held in close contact with the holding surface 14 of the holding table 21 without causing suction leakage, the grinding device 30 can grind the workpiece 1 without degrading the processing quality (machining quality). In particular, in the grinding device 30, when grinding, each grinding wheel 36 starts contacting the workpiece 1 from the outer edge and moves toward the center. If there is warping or lifting from the holding surface 14 on the outer circumference of the workpiece 1, the outer circumference of the workpiece 1 may be excessively ground, or the outer circumference of the workpiece 1 may be damaged by impact from the contact of the grinding wheel 36. By applying the holding table 21 of this embodiment, such problems can be avoided.

[0065] Furthermore, the outer peripheral holding portion 24 of the holding table 21 has excellent durability due to its configuration combining a first member 22 and a second member 23 with different hardnesses. This reduces the frequency of replacement and maintenance of the holding table 21 due to deterioration of the outer peripheral holding portion 24 (such as the occurrence of permanent deformation). As a result, excellent effects are obtained in terms of high productivity and low operating costs in the grinding device 30.

[0066] Figure 6 shows an example of a processing apparatus and processing steps, specifically a splitting step in which the object to be processed 1 is split using a cutting device 40. After the surface of the object to be processed 1 has been ground in the grinding step shown in Figure 5, it is transported to the cutting device 40, where cutting is performed to split the object to be processed 1.

[0067] The cutting apparatus 40 includes a holding table 41 with a different configuration from the holding tables 10 and 21 of the embodiments described above. The holding table 41 has a porous member 44 in a recess 43 on the upper side of the frame 42, and the holding surface 45 of the holding table 41 is formed by the upper surface of the frame 42 and the upper surface of the porous member 44. The recess 43 is connected to a suction source 47 via a flow path 46, and by operating the suction source 47, air is sucked out of the porous member 44 in the recess 43, thereby applying a suction force to the holding surface 45. The holding table 41 does not have the outer peripheral holding parts 20 and 24 of the holding tables 10 and 21 of the embodiments.

[0068] The holding table 41 is equipped with a plurality of clamps 48 located outside and below the holding surface 45. Each clamp 48 has a support portion 481 and a pressing portion 482 that can be opened and closed relative to the support portion 481.

[0069] When cutting with the cutting device 40, a flexible tape 5 is attached to one side of the object to be processed 1, and the object to be processed 1 is supported inside the opening of a support frame 6, which has an opening in the center, via the tape 5.

[0070] A processing object unit 7, consisting of the object to be processed 1, tape 5, and support frame 6, is held on a holding table 41. The object to be processed 1 is held by suction to the holding surface 45 of the holding table 41 via tape 5. The clamp 48 is pulled down to a position lower than the holding surface 45 of the holding table 41, supporting the lower surface of the support frame 6 with its support portion 481, and the upper surface of the support frame 6 is pressed down and fixed by its pressing portion 482.

[0071] Even if the outer circumference of the object to be processed 1 is warped, the support frame 6 can be pulled down with the clamp 48, which suppresses the warping of the object to be processed 1 by the tension of the tape 5, preventing the outer circumference of the object to be processed 1 from lifting up and allowing it to be held in place by suction on the holding surface 45.

[0072] The cutting device 40 is equipped with a table rotation mechanism 49 that rotates the holding table 41 around an axis in the Z-axis direction. The table rotation mechanism 49 includes a motor and a power transmission mechanism (not shown), and the driving force of the motor is transmitted to the holding table 41 by the power transmission mechanism, causing the holding table 41 to rotate.

[0073] The cutting device 40 includes a cutting unit 50 positioned above the holding table 41. In the cutting unit 50, a cutting blade 52 is mounted on the tip of a spindle 51, which is a rotating shaft extending horizontally. The cutting blade 52 is annular in shape and is sandwiched between a blade base 53 fixed to the spindle 51 and a blade retainer 54 that is detachable from the spindle 51, and secured with a fixing nut 55.

[0074] The spindle 51 rotates around a horizontal axis by a spindle rotation mechanism 56, which includes a bearing and a spindle motor. The cutting blade 52 rotates as the spindle 51 rotates.

[0075] The holding table 41 and the cutting unit 50 can be moved relative to each other in the direction along the axis of the spindle 51 (left-right direction in Figure 6) by an indexing feed mechanism (not shown). Furthermore, the holding table 41 and the cutting unit 50 can be moved relative to each other in the horizontal direction perpendicular to the axis of the spindle 51 (direction perpendicular to the plane of the paper in Figure 6) by a machining feed mechanism (not shown). Additionally, the holding table 41 and the cutting unit 50 can be moved relative to each other in the vertical direction (Z-axis direction) by a lifting mechanism (not shown). In short, the holding table 41 and the cutting unit 50 can be moved relative to each other in three mutually perpendicular axial directions (two orthogonal directions in the horizontal direction and a vertical direction perpendicular to the horizontal direction).

[0076] When the cutting device 40 cuts and divides the workpiece 1, the workpiece 1 is held by suction to the holding surface 45 of the holding table 41 via tape 5, and the support frame 6 is fixed by clamp 48. The relative position of the holding table 41 and the cutting unit 50 in the horizontal direction is adjusted by the operation of the indexing feed mechanism and the machining feed mechanism to position the cutting blade 52 above the extension of the division line that is to be cut.

[0077] Next, the spindle rotation mechanism 56 is operated to rotate the spindle 51 and the cutting blade 52, while the lifting mechanism is operated to move the holding table 41 and the cutting unit 50 relatively in the vertical direction until the cutting blade 52 reaches a height position where it can cut into the workpiece 1. Then, the processing feed mechanism is operated to move the holding table 41 and the cutting unit 50 relatively in the processing feed direction, causing the rotating cutting blade 52 to cut into the workpiece 1 and perform cutting along the planned division line.

[0078] Once cutting along one planned division line is complete, the lifting mechanism is operated to move the cutting blade 52 above the workpiece 1, and the indexing feed mechanism is operated to position the cutting blade 52 above the extension of the next uncut planned division line. Then, similarly to the above, the lifting mechanism is operated to position the cutting blade 52 at a height where it will cut into the workpiece 1, and then the machining feed mechanism is operated to cause the rotating cutting blade 52 to cut into the workpiece 1 and perform cutting along the planned division line.

[0079] Once cutting along all parallel division lines is complete, the table rotation mechanism 49 rotates the holding table 41 by 90 degrees. This causes the workpiece 1 on the holding table 41 to have multiple uncut division lines aligned in the indexing feed direction (each uncut division line extends in the machining feed direction). Then, in the same manner as above, cutting is sequentially performed along all uncut division lines by the cutting blade 52.

[0080] In this way, cutting is performed by the cutting blade 52 along multiple grid-like division lines on the object to be processed 1. In the processing example shown in Figure 6, the cutting blade 52 penetrates the object to be processed 1 in the thickness direction and forms a full-cut groove 8 that reaches partway down the tape 5. Once the full-cut groove 8 is formed, the cutting process by the cutting device 40 divides the object into individual chips 3, completing the division step. After cutting by the cutting device 40, the individual chips 3 can be picked up (removed from the tape 5) to obtain multiple completed chips 3 after division.

[0081] Unlike the processing example shown in Figure 6, the cutting blade 52 may cut partway through the thickness direction of the workpiece 1 to form a bottomed half-cut groove. After the half-cut groove is formed, the workpiece 1 can be divided starting from the half-cut groove by expanding the tape 5 with an expander or by pressing the tape 5 with a braking blade or roller breaker provided by a braking device, thereby manufacturing individual chips 3. In this case, the cutting performed by the cutting device 40 is part of the division step, and the division step includes subsequent processes such as expanding the tape with the expander and pressing with the braking device.

[0082] Figure 7 shows a different form of the division step, which divides the object to be processed 1, as an example of a processing step. In this different form, processing is performed on the object to be processed 1 using a cutting device 60, which is a processing device. The difference from the division step described with reference to Figure 6 is that the cutting device 60 applied to the division step in Figure 7 is equipped with the holding table 10 of the first embodiment described earlier.

[0083] During cutting with the cutting device 60, a protective member 9 is attached to the lower surface of the workpiece 1. In the holding step, in which the workpiece 1 is held on the holding surface 14 of the holding table 10, the workpiece 1 is held by suction to the holding surface 14 via the protective member 9. The outer periphery of the protective member 9 is in close contact with the outer periphery holding portion 20 (first member 18) of the holding table 10, preventing leakage of suction force, and the workpiece 1 is held on the holding table 10 in a stable state, eliminating the effects of warping.

[0084] The cutting unit 50 of the cutting device 60 is an example of a processing unit that processes the workpiece 1 held on the holding table 10. The configuration of the cutting unit 50 in the cutting device 60 is the same as that of the cutting unit 50 in the cutting device 40 in Figure 6, so its explanation is omitted. Furthermore, the processing of cutting the workpiece 1 using the cutting unit 50 in the cutting device 60 (dividing multiple chips 3 by forming a full-cut groove 8) is the same as the processing described for the cutting device 40 in Figure 6, so its explanation is omitted.

[0085] As shown in Figure 7, when forming a full-cut groove 8 in the object to be processed 1, the cutting blade 52 cuts partway through the thickness of the protective member 9. By providing the protective member 9, the cutting blade 52 that fully cuts the object to be processed 1 is prevented from cutting into the structure of the holding table 10. Therefore, the outer peripheral holding portion 20 is not damaged by the cutting blade 52, and no leakage of suction force occurs due to damage to the outer peripheral holding portion 20.

[0086] Furthermore, if the cutting performed on the workpiece 1 by the cutting device 60 is not to form a full-cut groove 8, but rather a bottomed half-cut groove, the workpiece 1 may be held directly on the holding surface 14 of the holding table 10 without attaching the protective member 9 to the workpiece 1.

[0087] By using a holding table 10 equipped with an outer peripheral holding portion 20, the workpiece 1 held on the holding table 10 can be machined with high precision during cutting in the cutting device 60, while preventing deterioration of processing quality (machining quality) due to the effects of warping.

[0088] Furthermore, the outer peripheral holding portion 20 of the holding table 10 has excellent durability due to its configuration combining a first member 18 and a second member 19 with different hardnesses. This reduces the frequency of replacement and maintenance of the holding table 10 due to deterioration of the outer peripheral holding portion 20 (such as the occurrence of permanent deformation). As a result, excellent effects are obtained in terms of high productivity and low operating costs in the cutting device 60.

[0089] Alternatively, the holding table 10 may be configured to include the clamp 48 shown in the holding table 41 of Figure 6, and the object to be processed 1 may be placed in the processing object unit 7 (with tape 5 and support frame 6 attached) shown in Figure 6 and held on the holding table 10. In other words, the holding table 41 of Figure 6 may be modified by adding the outer peripheral holding portion 20 of the holding table 10. The effect of preventing leakage of suction force due to the provision of the outer peripheral holding portion 20 and the effect of tight contact with the holding surface 14 (44) due to the pulling down of the support frame 6 via the clamp 48 work synergistically to more reliably and stably hold the object to be processed 1, which has a curved outer circumference, on the holding surface 14 (44).

[0090] As can be seen from the configurations in Figure 6 and Figure 7, the division step of dividing the object to be processed 1 to produce multiple chips 3 includes both cases: one in which the object to be processed 1 is held by a holding table 10(21) of this disclosure equipped with an outer peripheral holding portion 20(24), and another in which the object to be processed 1 is held by a different type of holding table 41 that is not equipped with an outer peripheral holding portion 20(24).

[0091] Furthermore, when a cutting device forms a half-cut groove in the workpiece 1 and then transports the workpiece 1 to another expanding or braking device for division, the cutting device may use the holding table 10(21) of this disclosure equipped with an outer peripheral holding portion 20(24) as shown in Figure 7, while the expanding or braking device may use a different type of holding table that does not have an outer peripheral holding portion 20(24). In this case, the holding table 10(21) of this disclosure is used in some substeps included in the division step, while it is not used in others.

[0092] In the embodiments described above, examples of processing performed on an object using the processing unit of the processing device include grinding with a grinding wheel (grinding wheel) (Figure 5) and cutting with a cutting blade (Figures 6 and 7), and also mention of braking with a braking blade and a roller breaker. The processing device and processing method of this disclosure are not limited to these processing examples, but can be applied to any processing performed by holding the object to be processed on a holding table.

[0093] In addition to the grinding, cutting, and braking processes mentioned above, other processing methods that can be applied to the object to be processed include laser irradiation, polishing with polishing pads, dry etching using plasma, wet etching using chemical solutions, cutting with a cutting tool, and cutting or drilling with high-pressure water. Furthermore, processes other than processing applied to the object to be processed can be applied, such as cleaning, imaging, inspection, attachment (adhesion) of protective members, removal of protective members, transport, and film formation. The technology of this disclosure can be applied to a holding table that holds the object to be processed when performing these various processes on the object, and to a processing apparatus equipped with said holding table. The technology of this disclosure can also be applied to a processing method that performs these various processes on the object to be processed, and to a chip manufacturing method that includes these various processes.

[0094] For example, as an application to the splitting step, a modified layer may be formed by irradiating the object to be processed along the planned splitting line, and then the modified layer may be used as the splitting starting point to manufacture multiple chips.

[0095] In the embodiments described above, a package substrate was given as an example of an object to be processed, but the objects to be processed held in the holding table of this disclosure, and the objects to be processed by the processing method and chip manufacturing method of this disclosure, are not limited to this.

[0096] For example, the material to be processed may be various types of wafers, such as semiconductor wafers on which semiconductor chips are formed, optical device wafers on which optical devices are formed, or material wafers on which no devices are formed, or it may be an ingot before the wafers are cut.

[0097] Furthermore, the object to be processed may be held on the holding table with protective members as shown in Figures 5 and 7, or with a support frame as shown in Figure 6, or it may be held on the holding table without protective members or a support frame. Various protective members can be selected for attachment to the object to be processed, such as tape with an adhesive layer, a sheet with only a base layer without an adhesive layer, a support substrate such as glass or silicone, or a cured resin obtained by curing liquid resin. In addition, a laminated protective member constructed by arbitrarily combining these may also be used.

[0098] Furthermore, the embodiments of the present invention are not limited to the embodiments and modifications described above, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Moreover, if the technical idea of ​​the present invention can be realized in a different way by advances in the art or by other derived arts, it may be implemented by that method. Accordingly, the claims cover all embodiments that may fall within the scope of the technical idea of ​​the present invention. [Industrial applicability]

[0099] The technology disclosed herein improves the processing quality of objects to be processed on the holding surface of the holding table, enables long-life and efficient operation of the holding table, and has a significant effect on the efficiency and cost reduction of various processes performed by holding objects to be processed on the holding table. [Explanation of Symbols]

[0100] 1: Object to be processed 3: Tip 10: Holding Table 11:Frame body 13: Porous material 14: Holding surface 17: Peripheral recess 18: First component (elastic component) 19: Second member (elastic member) 20: Outer peripheral holding part (outer peripheral part) 21: Holding Table 22: First component (elastic component) 23: Second component (elastic component) 24: Outer peripheral holding part (outer peripheral part) 25: Mounting part 27: Mounting parts 28: Fixing bolts 30: Grinding equipment (processing equipment) 32: Grinding unit (processing section) 35: Grinding Wheel 36: Grinding Wheel 40: Cutting equipment (processing device) 41: Holding Table 42: Frame 44: Porous material 45: Holding surface 48: Clamp 50: Cutting unit (processing unit) 51: Spindle 52: Cutting blade 60: Cutting equipment 231: Protruding section

Claims

1. A storage table, It has a holding surface for holding the object to be processed, The retaining surface is, A first member that comes into contact with the object to be processed, A second member supporting the first member, and an outer peripheral portion in which the two are laminated, A holding table characterized in that the hardness of the second member is higher than that of the first member.

2. The holding table according to claim 1, characterized in that the first member and the second member are elastic members.

3. The holding table according to claim 1 or 2, An apparatus comprising: a processing unit for processing an object to be processed held on the holding surface of the holding table.

4. A processing method for processing objects held in a holding table, The holding surface of the holding table is A first member that comes into contact with the object to be processed, A second member supporting the first member, and an outer peripheral portion in which the two are laminated, The hardness of the second member is higher than that of the first member. A holding step of holding the object to be processed on the holding surface, A processing method characterized by comprising a processing step of processing the object to be processed after the holding step.

5. A method for manufacturing chips, in which chips are produced from objects to be processed held on a holding table, The holding surface of the holding table is A first member that comes into contact with the object to be processed, A second member supporting the first member, and an outer peripheral portion in which the two are laminated, The hardness of the second member is higher than that of the first member. A holding step of holding the object to be processed on the holding surface, A grinding step of grinding the object to be processed held on the holding surface, A division step in which the object to be processed is divided to produce multiple chips, A method for manufacturing chips, characterized by comprising the following features.

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