Holding mechanism and cutting device having the same

Abstract

The present invention aims to provide a holding mechanism and a cutting device provided with the holding mechanism, which can make the separation quality of a wafer during dicing good by pressing and holding a wafer mounted on a worktable in a flat state when the wafer is dicing by a blade. The holding mechanism (16) of the present invention is provided in a cutting device (1) which mounts a wafer (2) in a state assembled in a ring frame (3) on a worktable (4), arranges a blade (6) in a manner consistent with a scribe line above, and lowers the blade (6) to press on the scribe line to thereby dice the wafer (2), wherein the holding mechanism (16) presses the wafer (2) mounted on the ring frame (3) to keep it in a flat state when the wafer (2) is diced by the blade (6).

Description

Technical Field

[0001] This invention relates to a technique for suppressing and holding a wafer during wafer breaking. Background Technology

[0002] Traditionally, for example, when separating wafers (such as brittle material substrates), in the scribing process, scribing lines are formed on the wafer using a scribing tool or laser irradiation. Then, in the dicing process, for example, the wafer is set with the scribing surface as the lower surface, and a cutting blade is pressed against the back of the scribing line to separate the wafer into multiple chip materials (unit substrates). Alternatively, there are methods that separate wafers by cutting with a dicing blade.

[0003] As a technology for breaking down wafers, there is, for example, the technology disclosed in Patent Document 1.

[0004] In Patent Document 1, for example, there is a cutting device that cuts a laminated brittle material substrate with a dissimilar material layer made of resin or metal attached to one main surface and scribe lines formed on the other main surface from the dissimilar material layer side along the scribe lines. The cutting device has a heater attached to the cutting rod that abuts against the laminated brittle material substrate during cutting, and the cutting is performed while the cutting rod is heated to a predetermined temperature by the heater.

[0005] Patent document 1: Japanese Patent Application Publication No. 2017-128137.

[0006] In addition, in recent years, very thin chips have been manufactured according to customer requirements. Such chips are prone to warping (bending in a bulging manner) due to their thinness. In other words, problems arise when the chip is divided into multiple chip materials (unit substrates).

[0007] For example, because the wafer warps on the cutting machine's table, it is difficult to focus when using a camera to identify alignment marks set on the wafer, and sometimes it may fail to identify them correctly. In other words, when cutting wafers to produce chip materials, the wafer needs to be pressed in a way that prevents it from warping when the blades come into contact.

[0008] In addition, due to the warping of the wafer, it may bounce or jerk when it comes into contact with the blade, which can lead to a deterioration in the cutting quality. Therefore, the blade needs to be pressed down with appropriate force.

[0009] However, although Figure 5 The existing cutting device 100 shown has a stage 400 for mounting the wafer 2 assembled on the annular frame 3, a cutting blade 600 for cutting the wafer 2, and a cutting unit 700 with the blade 600, but it is difficult to solve the above-mentioned problems. Summary of the Invention

[0010] Therefore, the present invention addresses the aforementioned problems and aims to provide a holding mechanism and a cutting device having the holding mechanism, which, when cutting a wafer with a blade, presses the wafer mounted on a worktable into a flat state and holds it in place, thereby enabling good wafer separation quality during cutting.

[0011] To achieve the above objectives, the following technical means are employed in this invention.

[0012] The holding mechanism of the present invention is a holding mechanism provided in a cutting device, which cuts the wafer by placing a wafer assembled in an annular frame on a worktable and positioning a blade above it in a manner consistent with a scribing line, and lowering the blade to press against the scribing line, thereby cutting the wafer. The characteristic feature is that when the wafer is cut by the blade, the holding mechanism presses the wafer mounted on the annular frame to keep it in a flat state.

[0013] Preferably, the holding mechanism has a pressing member for pressing the wafer, the pressing member being formed of a rigid body and configured to surround the blade from both sides along the blade.

[0014] Preferably, the pressing member has a specified weight, and the surface of the pressing member that abuts against the wafer has a specified flatness.

[0015] Preferably, the holding mechanism includes a load control unit that controls the load applied to the wafer by the pressing member.

[0016] Preferably, the retaining mechanism has the following structure: during maintenance, the blade can be made to protrude downward from the pressing member, thereby measuring the height of the blade.

[0017] Preferably, a low-friction sheet is disposed on the surface of the pressing member that abuts against the wafer.

[0018] The cutting device of the present invention includes: a substrate mounting portion; a substrate cutting blade movable vertically relative to the upper surface of the substrate mounting portion; and a holding mechanism for holding the substrate in the substrate mounting portion. The holding mechanism is characterized by having: pressing members located on both sides of the blade, wherein when the blade presses against the upper surface of the substrate disposed on the upper surface of the substrate mounting portion to cut the substrate, the pressing members contact the upper surface of the substrate before the blade contacts the upper surface of the substrate to press the substrate, and the pressing members separate from the upper surface of the substrate and move upward when or after the blade separates from the upper surface of the substrate.

[0019] Preferably, the holding mechanism includes a load control unit for controlling the load of the pressing member pressing the substrate.

[0020] Preferably, the substrate is a wafer assembled in an annular frame, the substrate mounting part is a worktable, and scribe lines are formed on the lower surface of the wafer. The holding mechanism has the following structure: during maintenance, the blade can protrude from the pressing member to measure the height of the blade. The pressing member is formed of a rigid body, has a specified weight, and the surface of the pressing member that abuts against the wafer has a specified flatness. A low-friction sheet is disposed on the surface of the pressing member that abuts against the wafer.

[0021] According to the holding mechanism of the present invention, when the wafer is cut using a blade, by pressing the wafer mounted on the worktable into a flat state and holding it, the separation quality of the wafer during cutting can be good. Attached Figure Description

[0022] Figure 1 This is a schematic perspective view showing a cutting device having the holding mechanism of the present invention.

[0023] Figure 2 This is an enlarged view showing the area around the holding mechanism of the present invention.

[0024] Figure 3 This is a schematic diagram illustrating the holding mechanism of the present invention.

[0025] Figure 4 This is a magnified diagram showing a portion of the retaining mechanism.

[0026] Figure 5 This is a schematic diagram showing an existing cutting device.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1: Cutting device

[0029] 2: Wafer (substrate)

[0030] 3: Circular frame

[0031] 4: Workbench

[0032] 5: Abutment

[0033] 6: Blade (cutting rod)

[0034] 7: Cut-off unit

[0035] 7a: Board

[0036] 8: Liang

[0037] 9: Position Adjustment Mechanism

[0038] 10: Threaded shaft

[0039] 11: Guide rail

[0040] 12: Support column

[0041] 13: Electric motor

[0042] 14: Guide rail

[0043] 15: Camera

[0044] 16: Holding mechanism (pressing mechanism)

[0045] 17: Pressing component (pressing plate)

[0046] 18: Planar section

[0047] 19: Extension component

[0048] 20: Hole

[0049] 21: Load Control Department

[0050] 22: Support section

[0051] 23: Load Absorption Section

[0052] 24: Spring

[0053] 25: Fasteners

[0054] 26: Blade Adjustment Section

[0055] 27: Spring

[0056] 28: Fasteners

[0057] 29: Assemble the nuts

[0058] 30: Adjusting nut Detailed Implementation

[0059] Hereinafter, embodiments of the holding mechanism 16 and the cutting device 1 having the holding mechanism 16 of the present invention will be described with reference to the accompanying drawings.

[0060] Furthermore, the embodiments described below are merely examples embodying the present invention, and are not intended to limit the structure of the present invention through these specific examples. Additionally, the X-axis direction, Y-axis direction, Z-axis direction, etc., are shown in the accompanying drawings.

[0061] like Figure 1As shown, the cutting device 1 of the present invention is a device in which a wafer 2 (substrate) with scribe lines is mounted on a worktable 4 in a state of being assembled on a cutting ring, and a blade 6 (blade) is arranged above it in a manner consistent with the scribe lines, so that the blade 6 is lowered and pressed on the scribe lines, thereby cutting the wafer 2.

[0062] Next, in the previous scribing process, the adhesive sheet is placed on the worktable 4 of the scribing apparatus with its back facing downwards. Using the scribing tool at the top of the scribing head located above the worktable 4, scribing lines (X-axis direction, Y-axis direction) are formed on the surface of the wafer 2. That is, scribing lines are formed on the surface of the wafer 2 in a grid pattern while the adhesive sheet is adhered to its back side.

[0063] Specifically, on the wafer 2, which is scribed in a grid pattern, the center portion of an adhesive sheet stretched and disposed inside an annular frame 3 (a disc-shaped ring member, a cutting ring) is adhered to the back side (lower surface) of the wafer 2, and scribe lines are formed on its surface (upper surface). After the scribe lines are formed in this state, a protective film (not shown) is disposed on the opposite upper surface (surface) as needed, and the wafer is usually cut with the upper and lower surfaces flipped. That is, the wafer 2, which is to be cut, is set in a state where it is assembled with a holding member such as the annular frame 3, the adhesive sheet (holding film), and the protective film.

[0064] Furthermore, because wafer 2 is very thin, it is prone to warping. When cutting wafer 2, it may bend in a bulging manner, which may cause problems such as the inability to properly identify the alignment marks printed on wafer 2 or the inability to separate them properly.

[0065] Therefore, the cutting device 1 of the present invention has a holding mechanism 16 that is able to hold the wafer 2 in a flat state (suppressing warping) during cutting.

[0066] like Figure 1 , Figure 2 As shown, the cutting device 1 includes: a worktable 4 on which a wafer 2 with scribe lines is placed; a base 5 supporting the worktable 4 from below; a blade 6 for cutting along the scribe lines formed on the wafer 2; a cutting unit 7 disposed above the wafer 2 and having the blade 6; and a beam 8 (beam member) on which the cutting unit 7 is disposed, etc.

[0067] In the worktable 4, a wafer 2 assembled on an annular frame 3 is mounted, and the annular frame 3 is fixed by a position adjustment mechanism 9. The position adjustment mechanism 9 positions the wafer 2, which is adhered to and assembled on the annular frame 3, relative to the blade 6 on the worktable 4, and holds it in this state.

[0068] The worktable 4 can move along the guide rail 11 in the Y-axis direction via a threaded shaft 10 rotated by an electric motor (not shown). Additionally, the worktable 4 can rotate about a vertical axis via a drive unit (not shown). The base 5 holds the worktable 4 at a certain height and supports it from below.

[0069] The beam 8 is configured to be supported on the workbench 4 by a pair of support columns 12 erected from the base 5. A cutting unit 7 is configured to be suspended from the beam 8.

[0070] The cutting unit 7 can move along the guide rail 14 in the Z-axis direction via a threaded shaft (not shown) rotated by a motor 13. A blade 6 is provided at the top of the cutting unit 7 to cut along the scribing line (vertical crack) formed on the wafer 2.

[0071] The blade 6 is an elongated strip-shaped component (cutting rod) extending along the X-axis. The length of the blade 6 matches the size of the wafer 2 to be cut. Under the action of the threaded shaft of the cutting unit 7 and the guide rail 14, the blade 6 remains parallel to the worktable 4 and moves up and down in the vertical direction (Z-axis direction). In addition, a camera 15 is provided near the blade 6 to identify the alignment marks provided on the wafer 2.

[0072] Furthermore, the present invention has a holding mechanism 16 (pressing mechanism) that presses the wafer 2 mounted on the annular frame 3 to hold it in a flat state when the wafer 2 is cut by the blade 6.

[0073] like Figures 2-4 As shown, the holding mechanism 16 has a pressing member 17 that presses the wafer 2.

[0074] The pressing member 17 (pressing plate) is a component that continuously presses down on the wafer 2 during the production of multiple chip materials, i.e., when the wafer 2 is cut. The pressing member 17 stabilizes the recognition of the alignment mark by the camera 15. In addition, the pressing member 17 can prevent problems caused by warping such as "bouncing" or "jumping" of the wafer 2 when it is cut.

[0075] The pressing member 17 is formed of a rigid body and has a flat portion 18 on its lower surface. The flat portion 18 serves as the surface that contacts the wafer 2. In this embodiment, the pressing member 17 is formed of an aluminum sheet. The pressing member 17 is not limited to being made of aluminum as long as it can press the wafer 2.

[0076] The pressing member 17 is mounted on the top end of the cutting unit 7. The pressing member 17 is configured such that the top end of the blade 6 can protrude downward when the wafer 2 is cut.

[0077] The pressing member 17 is configured to surround the blade 6 from the side. The pressing member 17 is configured to surround the blade 6 at least from the X-axis direction. That is, the pressing member 17 is formed such that the blade 6 (cutting rod) is clamped by a pair of extension members 19.

[0078] In this embodiment, the pressing member 17 is formed from a single sheet of material, with a slit-shaped hole 20 formed in its center. A pair of extending members 19 are located on either side of the hole 20. A flat portion 18 is provided below the extending members 19.

[0079] Furthermore, to prevent vibrations caused by the movement (acceleration) of the stage 4 during wafer 2 positioning, the pressing member 17 has a predetermined weight. Therefore, in this embodiment, the pressing member 17 (pressing plate) is made of aluminum. In addition, the surface that abuts against the wafer 2, i.e., the flat portion 18, has a predetermined flatness so as not to affect the wafer 2.

[0080] Furthermore, the shape of the pressing member 17 (pressing plate) is not limited to the shape illustrated in this embodiment.

[0081] However, if the entire weight of the pressing member 17 (pressing plate) is applied directly to the wafer 2, it will cause damage to the wafer 2. Therefore, the holding mechanism 16 has a load control unit 21 for controlling the load applied by the pressing member 17 to the wafer 2.

[0082] The load control unit 21 prevents the pressing member 17 from applying its full weight to the wafer 2, maintaining a constant pressing force. In this embodiment, the load control unit 21 uses a spring 24 (coil spring) to float the pressing member 17, offsetting the weight of the pressing member 17 by a predetermined amount. A pair of load control units 21 are arranged in the X direction.

[0083] Specifically, the load control unit 21 includes: a support unit 22 for supporting the pressing member 17; and a load absorption unit 23 for absorbing a predetermined amount of load from the pressing member 17 when pressing the wafer 2.

[0084] The support portion 22 is an L-shaped component, mounted to the cutting unit 7 via the load-absorbing portion 23. The support portion 22 has multiple through holes on its edge portion 22a. In this embodiment, three through holes are arranged in the Y-axis direction. Fasteners 25 (bolts) constituting the load-absorbing portion 23 are inserted into two of the through holes. On the other hand, a fastener 28 (bolt) constituting the blade adjustment portion 26 is inserted into one of the through holes. Alternatively, the support portion 22 may be integrally formed with the pressing member 17.

[0085] The load absorption section 23 includes: an absorption member 24 (spring) that absorbs a specified amount of load from the pressing member 17 when pressing the wafer 2; and a fastener 25 (bolt) that mounts the support section 22 to the cutting unit 7.

[0086] A spring 24 (coil spring) is disposed between the support portion 22 and the cutting unit 7. In this embodiment, two springs 24 are arranged in a manner that runs along the Y-axis. Furthermore, the springs 24 are configured to connect with both the support portion 22 and the cutting unit 7.

[0087] Bolt 25 is fastened to cutting unit 7 via spring 24 through through hole in support portion 22. Support portion 22 is movable on axis (along the Z-axis direction) of bolt 25. That is, bolt 25 maintains a certain distance from cutting unit 7 while holding support portion 22.

[0088] That is, when the load-absorbing part 23 cuts the wafer 2, the cutting unit 7 descends, and when the flat part 18 of the pressing member 17 contacts the wafer 2 and becomes flat, the support part 22 rises on the axis of the bolt 25 due to the reaction force, thereby causing the spring 24 to contract and reducing the load applied to the wafer 2 by the pressing member 17, thus applying a specified pressing force to the wafer 2. Therefore, the force applied by the pressing member 17 to the wafer 2 is only the necessary amount.

[0089] Alternatively, a low-friction sheet can be disposed on the surface of the pressing member 17 that abuts against the wafer 2. Examples of low-friction sheets include sheets made of polymers. By sandwiching the low-friction sheet between the pressing member 17 and the wafer 2, friction on the surface of the pressing member 17 that contacts the wafer 2 can be avoided.

[0090] Additionally, the height of the blade 6 is sometimes measured during routine maintenance. Therefore, the retaining mechanism 16 has a blade adjustment section 26, which allows the blade 6 to protrude from the pressing member 17 during routine maintenance, thereby measuring the height of the blade 6 (its position in the vertical direction (Z-axis direction)). A pair of blade adjustment sections 26 are arranged in the X direction.

[0091] The blade adjustment part 26 includes: a moving member 27 (spring) that allows the support part 22 to move in the vertical direction (Z-axis direction) during maintenance; a fastener 28 (bolt) that is installed on the support part 22; a mounting nut 29 that fixes the bolt 28; and an adjusting nut 30 that allows the height of the blade 6 to be adjusted during maintenance.

[0092] A spring 27 (coil spring) is disposed on the upper side of the plate 7a constituting the cutting unit 7. In this embodiment, one spring 27 is disposed.

[0093] Bolt 28 is fastened to support portion 22 and is configured through a through hole in plate 7a of cutting unit 7. Spring 27 is configured on the axis of bolt 28, which protrudes upward from plate 7a. Bolt 28 is movable along the Z-axis. Mounting nut 29 and adjusting nut 30 are mounted on the top end of bolt 28.

[0094] The mounting nuts 29 are set and tightened in an overlapping manner (double nuts). The adjusting nut 30 is located below the mounting nuts 29 and above the spring 27. The adjusting nut 30 and the spring 27 are configured to be connected.

[0095] That is, during periodic maintenance, the blade adjustment part 26 changes the position of the adjusting nut 30 by moving it away from the mounting nut 29 (lowering it down), thereby compressing the spring 27 and lifting the pressing member 17. As a result, since the tip of the blade 6 protrudes downward from the hole 20 of the pressing member 17 and contacts the tip of the blade 6 with the measuring terminal, the height (vertical position) of the blade 6 can be measured using the measuring terminal.

[0096] Furthermore, during the assembly of the cutting device 1, the mounting nut 29 and adjusting nut 30 are adjusted to pre-adjust the force of the pressing member 17 pressing the wafer 2 (for the load that allows the blade 6 to protrude appropriately during cutting). The mounting nut 29 is fully tightened. When cutting the wafer 2, the adjusting nut 30 is positioned to abut against the mounting nut 29. On the other hand, when measuring the height of the blade 6, the adjusting nut 30 is lowered so that the tip of the blade 6 protrudes from the hole 20 of the pressing member 17.

[0097] [Work Style]

[0098] Next, the operation of the cutting device 1 of the present invention will be described.

[0099] In the cutting process, the annular frame 3 with the scribed lines facing downwards is mounted on the annular worktable 4 of the cutting device 1. The wafer 2 is positioned by the position adjustment mechanism 9 and held in this state.

[0100] A blade 6 is positioned on the upper side in a manner consistent with the scribing formed on the wafer 2, and a set of receiving blades is positioned on both sides of the lower side of the wafer 2, opposite to the blade 6. The receiving blades are positioned to support both sides of the scribing directly from the surface side of the wafer 2 or via an adhesive sheet.

[0101] In this process, the cutting unit 7 descends. The blade 6 remains parallel to the worktable 4 and descends. Consequently, the pressing member 17 (pressing plate) of the holding mechanism 16 (pressing mechanism) descends, and the flat portion 18 contacts the wafer 2, suppressing warping and achieving a flat state. At this time, the camera 15 installed in the cutting unit 7 accurately identifies the alignment marks printed on the wafer 2.

[0102] If it descends further, the blade 6 protrudes from the hole 20 of the pressing member 17. The blade 6 presses the upper surface of the wafer 2 from the back side of the wafer 2 through the protective film (not shown) and directly above the scribed line.

[0103] At this time, in the load control unit 21, the support unit 22 rises on the shaft of the bolt 25 due to the reaction force of the pressing, and the spring 24 of the load absorption unit 23 contracts, thereby reducing the load (total weight) applied to the wafer 2 by the pressing member 17 and applying the prescribed pressing force to the wafer 2.

[0104] By pressing with the blade 6, cracks are created on the wafer 2 along the vertical direction, and the wafer 2 is cut along the scribe line, thereby manufacturing multiple chip materials (unit substrates). In other words, the wafer 2 after the cutting process is held on the bonding sheet in a state where it has been divided into multiple chip materials that have been cut in a grid pattern.

[0105] According to the present invention, the holding mechanism 16 of the cutting device 1 holds the wafer 2 mounted on the worktable 4 in a flat state when the wafer 2 is cut by the blade 6, thereby enabling good separation quality of the wafer 2 during cutting.

[0106] Furthermore, the present invention is a cutting device 1, which includes a substrate mounting portion 4; a substrate cutting blade 6, which is movable vertically relative to the upper surface of the substrate mounting portion 4; and a holding mechanism 16 for holding a substrate 2 in the substrate mounting portion 4. The holding mechanism 16 is characterized by having pressing members 17 located on both sides of the blade 6. When the blade 6 presses against the upper surface of the substrate 2 disposed on the upper surface of the substrate mounting portion 4 and cuts the substrate 2, the pressing members 17 press against the upper surface of the substrate 2 before the blade 6 contacts the upper surface of the substrate 2. The pressing members 17 also press against the upper surface of the substrate 2 when or after the blade 6 separates from the upper surface of the substrate 2 and moves upward.

[0107] Preferably, the holding mechanism 16 has a load control unit 21 that controls the load of the pressing member 17 pressing the substrate 2.

[0108] Preferably, the substrate 2 is a wafer 2 assembled in an annular frame 3, the substrate mounting part 4 is a worktable 4, and a scribing line is formed on the lower surface of the wafer 2; the holding mechanism 16 has the following structure: during maintenance, the blade 6 can be protruded from the pressing member 17 and the height of the blade 6 can be measured. The pressing member 17 is formed of a rigid body, has a specified weight, and has a specified flatness on the surface that abuts against the wafer 2. A low-friction sheet can be disposed on the surface of the pressing member 17 that abuts against the wafer 2.

[0109] Furthermore, the embodiments disclosed herein should be considered illustrative rather than restrictive in all respects.

[0110] In particular, in the embodiments disclosed herein, matters not explicitly stated, such as working conditions, operating conditions, dimensions and weight of components, do not depart from the scope of what is usually practiced by those skilled in the art, and adopt matters that would be easily conceived by those skilled in the art.

[0111] The holding mechanism 16 (pressing mechanism) of the present invention can also be provided in the scribing device for forming scribing lines on the wafer 2 (substrate).

Claims

1. A substrate cutting device, comprising: Substrate mounting section; The cutting unit is capable of moving up and down relative to the upper surface of the substrate mounting portion; A blade for cutting the substrate is disposed at the top of the cutting unit; as well as A holding mechanism is used to press and hold the substrate in the substrate mounting portion, wherein, The retaining mechanism has: A pressing member, disposed at the top end of the cutting unit, is used to press the substrate; and A support portion supports the pressing member and is disposed on the cutting unit in a manner that allows it to move vertically relative to the cutting unit. The pressing members are located on both sides of the blade. When the blade presses the upper surface of the substrate disposed on the upper surface of the substrate mounting part to cut the substrate, the pressing members contact the upper surface of the substrate before the blade contacts the upper surface of the substrate to press the substrate. When or after the blade separates from the upper surface of the substrate and moves upward, the pressing members separate from the upper surface of the substrate and move upward.

2. The substrate cutting device according to claim 1, wherein, The holding mechanism includes a load control unit that controls the load on which the pressing member presses the substrate.

3. The substrate cutting device according to claim 2, wherein, The load control unit is disposed between the cutting unit and the support unit, and has a spring that counteracts the weight of the pressing member by a predetermined amount.

4. The substrate cutting apparatus according to any one of claims 1 to 3, wherein, The retaining mechanism has the following structure: during maintenance, the blade can be protruded from the pressing member to measure the height of the blade.

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