Wafer processing method, protective member attaching device, and processing device

Abstract

Provided are a wafer processing method, a protective member attaching device, and a processing device that reduce the influence of a change in the thickness of a protective member on processing conditions such as grinding even when the thickness of the protective member changes before and after heating and pressing. A wafer processing method for processing a wafer having a device on a front surface side includes a wafer with protective member forming step of forming a wafer with a protective member by pressing and attaching a protective member formed of a resin softened by heat to the front surface side of the wafer while heating the protective member; a thickness measuring step of measuring the thickness of the protective member of the wafer with the protective member; a grinding step of holding the wafer with the protective member using a holding surface of a chuck table, grinding the back surface side of the wafer to a target finished thickness of the wafer, calculating the thickness of the wafer by subtracting the measured thickness of the protective member from the total thickness of the wafer with the protective member, and grinding the back surface side of the wafer.

Description

Technical Field

[0001] The present invention relates to a wafer processing method for grinding the back side of a wafer after attaching a protective component to the front side of a wafer having a device on the front side, a protective component attachment apparatus for attaching a protective component to the front side of a wafer, and a processing apparatus having a protective component attachment apparatus and a grinding apparatus. Background Technology

[0002] Device chips mounted in electronic devices are manufactured, for example, by forming devices in various regions on the front side of a silicon wafer, which are divided by multiple predetermined dividing lines set on the front side, and then by grinding and cutting the back side of the wafer.

[0003] When grinding wafers, a resin-based protective strip is attached to the front side of the wafer to reduce the risk of wafer breakage and prevent grinding debris from adhering to the front side. The protective strip, for example, consists of a resin-based substrate layer and a resin-based adhesive layer (paste layer).

[0004] When attaching the protective tape to the front side of the wafer, firstly, the protective tape is positioned on the wafer with the paste layer side facing the front side. Next, the protective tape is softened by heating the substrate layer side and then pressed to ensure it adheres tightly to the unevenness of the front side of the wafer. However, in this case, the thickness of the protective tape may sometimes be slightly thinner than before heating and pressing.

[0005] Furthermore, when using a protective tape with a paste layer, adhesive residue sometimes remains on electrode bumps or the like when the protective tape is peeled off, and this residue becomes a cause of defects in the electrode bumps. Therefore, a technique has been proposed in which a sheet-like protective member without a paste layer is softened by heating it, while simultaneously making the protective member tightly bonded to the front side of the wafer (for example, see Patent Document 1).

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-169727

[0007] However, similar to protective sheets with a paste layer, protective components without a paste layer can also become slightly thinner depending on bonding conditions such as heating temperature and pressing time. When the thickness of the protective component changes, for example, when grinding the wafer to a specified finished thickness, grinding conditions such as the grinding feed rate may change. Summary of the Invention

[0008] The present invention was made in view of the above-mentioned problems, and its object is to reduce the impact of the change in the thickness of the protective component on processing conditions such as grinding, even when the thickness of the protective component changes before and after heating and pressing.

[0009] According to one aspect of the present invention, a wafer processing method is provided for processing a wafer having devices on its front side, wherein the wafer processing method comprises the following steps: a wafer forming step with a protective member, wherein a protective member formed of a resin capable of softening due to heat is heated and pressed toward the front side of the wafer to adhere the protective member to the front side of the wafer, thereby forming a wafer with a protective member; a thickness measurement step, wherein the thickness of the protective member of the wafer with a protective member is measured; and a grinding step, wherein the wafer with a protective member is held using a chuck stage and the back side of the wafer is ground until the wafer reaches a target finished thickness, wherein the thickness of the wafer is calculated by subtracting the thickness of the protective member measured in the thickness measurement step from the total thickness of the wafer with a protective member, and the back side of the wafer is ground.

[0010] Preferably, the protective component used in the wafer forming step is a monolithic sheet formed by pressing a thermoplastic resin that can be softened by heat.

[0011] According to another aspect of the invention, a protective component bonding apparatus is provided, which bonds a protective component to the front side of a wafer having a device on the front side. The protective component bonding apparatus comprises: a protective component bonding unit having a support stage and a pressing body, which uses the pressing body and the support stage to heat the protective component, which is formed of a resin that can soften due to heat, while pressing the protective component toward the front side of the wafer, thereby bonding the protective component to the front side of the wafer to form a wafer with a protective component; a thickness measuring unit having a thickness measuring instrument and measuring the thickness of the protective component in the wafer with the protective component; and a transmitting unit for transmitting the information on the thickness of the protective component measured by the thickness measuring unit to the outside of the protective component bonding apparatus.

[0012] According to another aspect of the present invention, a processing apparatus is provided, comprising: a protective component bonding device for bonding a protective component to the front side of a wafer having a device on the front side; and a grinding apparatus for grinding the wafer to which the protective component is bonded on the front side, wherein the protective component bonding device comprises: a protective component bonding unit having a support table and a pressing body, the protective component bonding device using the pressing body and the support table to heat the protective component, which is formed of a resin that can soften due to heat, while pressing the protective component toward the front side of the wafer, thereby bonding the protective component to the front side of the wafer to form a wafer with a protective component; a thickness measuring unit having a thickness measuring instrument for measuring the thickness of the protective component in the wafer with the protective component; and a transmitting unit for transmitting the information of the thickness of the protective component measured by the thickness measuring unit to the grinding apparatus, the grinding apparatus comprising: a chuck operator. The processing apparatus includes a worktable that holds the wafer with protective components; a grinding unit having a cylindrical spindle and an annular grinding wheel mounted on the lower end of the spindle, which grinds the back side of the wafer held by the chuck worktable on the front side; and a grinding feed unit that feeds the grinding unit toward the chuck worktable. The processing apparatus also includes a control unit with a processor that controls the operation of the grinding feed unit. The control unit has a recording unit that records information on the thickness of the protective components measured by the thickness measuring unit, information on the total thickness of the wafer with protective components, and information on the target finished thickness of the wafer after grinding. The thickness of the wafer is calculated by subtracting the thickness of the protective components from the total thickness of the wafer with protective components. The operation of the grinding feed unit is controlled to grind the back side of the wafer, thereby grinding the wafer until the wafer reaches the target finished thickness.

[0013] One aspect of the wafer processing method of the present invention includes a wafer forming step with a protective component, a thickness measurement step for measuring the thickness of the protective component of the wafer with the protective component, and a grinding step for grinding the back side of the wafer. Furthermore, in the grinding step, the thickness of the wafer is calculated by subtracting the thickness of the protective component measured in the thickness measurement step from the total thickness of the wafer with the protective component.

[0014] Therefore, even if the thickness of the protective component changes before and after heating and pressing, the impact of the change in the thickness of the protective component on the processing conditions can be reduced. That is, even if the thickness of the protective component changes, the wafer can be processed based on the correctly set processing conditions to achieve the target finished thickness.

[0015] In addition, another aspect of the protective component bonding apparatus of the present invention includes: a protective component bonding unit that heats and presses a protective component formed of a resin that can be softened by heat to bond the protective component to the front side of the wafer, thereby forming a wafer with a protective component; a thickness measuring unit that measures the thickness of the protective component in the wafer with the protective component; and a sending unit that sends the thickness of the protective component measured by the thickness measuring unit to the outside of the protective component bonding apparatus.

[0016] Therefore, even if the thickness of the protective component changes before and after heating and pressing, information about the changed thickness of the protective component can be transmitted from the transmitting unit to the outside of the protective component bonding device. If this information about the thickness of the protective component is used to process the wafer, the impact of changes in the thickness of the protective component on the processing conditions can be reduced. Attached Figure Description

[0017] Figure 1 It is a 3D view of the chip.

[0018] Figure 2 This is a block diagram showing an outline of a protective component pasting device, etc.

[0019] Figure 3 (A) is a perspective view of the protective component forming unit, etc. Figure 3 (B) is a three-dimensional view of the protective component.

[0020] Figure 4 It is a partial cross-sectional side view of the protective component bonding unit, etc.

[0021] Figure 5 This diagram illustrates how air pressure difference allows the protective component to be in close contact with the front side of the chip.

[0022] Figure 6 This is a diagram illustrating the wafer formation steps with protective components.

[0023] Figure 7 This is a diagram showing the steps for cutting open the protective component.

[0024] Figure 8 This is a diagram illustrating the thickness measurement steps.

[0025] Figure 9 This is a diagram showing the grinding process.

[0026] Figure 10 This is a flowchart of the wafer fabrication process.

[0027] Figure 11 This is a block diagram showing an outline of the processing apparatus.

[0028] Label Explanation

[0029] 10, 110: Protective component bonding device; 11: Wafer; 11a: Front side; 11b: Back side; 12: Protective component forming unit; 13: Pre-defined dividing line; 14: Worktable; 15: Device; 16: Pressing body; 17: Bump; 19a: Device area; 19b: Remaining peripheral area; 20: Protective component bonding unit; 20a: Lower main body; 20b: Annular plate; 20c: Upper main body; 20d: First space; 20e: Second space; 21: 22: Particle; 22: Chuck worktable; 22a: Holding surface; 23: Protective component; 23a: Cutting slit; 24a: Frame; 24b: Perforated plate; 24c: Annular groove; 24d: Flow path; 26: Exhaust section; 26a: Exhaust pipe; 26b: Suction source; 28: Exhaust section; 28a: Exhaust pipe; 28b: Suction source; 30: Air supply section; 30a: Air supply pipe; 30b: Solenoid valve; 32: Pressing body; 32a: Lower surface; 32b: Heating element; 34: Cut-off Mechanism; 34a: Arm; 34b: Output shaft; 34c: Cutting edge; 36: Thickness measuring unit; 36a: Thickness measuring instrument; 38: Sending unit; 40: Control unit; 50, 150: Grinding device; 52: Chuck table; 52a: Holding surface; 54: Grinding feed unit; 56: Guide rail; 58: Moving plate; 60: Nut part; 62: Ball screw; 64: Pulse motor; 68: Grinding unit; 70: Holding component; 72: Spindle housing; 74 76: Spindle; 78: Grinding wheel; 78a: Grinding wheel base; 78b: Grinding tool; 80: Grinding water; 82: Nozzle; 86: Thickness measuring instrument; 86a: First height gauge; 86b: Second height gauge; 88: Control unit; 88a: Processor; 88b: Auxiliary storage device; 88c: Recording unit; 90: Receiving unit; 92: Machining device; 94: Control unit; 94a: Processor; 94b: Auxiliary storage device; 94c: Recording unit. Detailed Implementation

[0030] An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. First, the disc-shaped wafer 11, which is the object of processing in the first embodiment, will be described. Figure 1 This is a 3D view of chip 11.

[0031] The wafer 11 is formed from semiconductor materials such as Si (silicon), SiC (silicon carbide), GaN (gallium nitride), and GaAs (gallium arsenide). Multiple pre-defined dividing lines 13 are arranged in a grid pattern on the front side 11a of the wafer 11.

[0032] Devices such as ICs (Integrated Circuits) and LSIs (Large Scale Integrations) are formed in various regions on the front side 11a, which is divided by multiple predefined dividing lines 13. Multiple bumps 17 are provided on each device 15.

[0033] Multiple bumps 17 are formed of metal materials such as gold, silver, and copper. Each bump 17 is electrically connected to the device 15 and protrudes, for example, about 100 μm from the upper surface of the device 15.

[0034] The central region of the wafer 11, which is equipped with multiple devices 15, is device region 19a. The outer periphery of device region 19a does not have devices 15 or bumps 17, and is surrounded by the remaining outer periphery region 19b, which is flatter than device region 19a.

[0035] When manufacturing a device chip from wafer 11, a protective component bonding device 10 (see reference 10) is used before grinding on the back side 11b of wafer 11. Figure 2 Protective component 23 (refer to) Figure 3 (B) is attached to the front side 11a of the chip 11.

[0036] Figure 2 This is a block diagram showing an outline of the protective component pasting device 10, etc., according to the first embodiment. First, using... Figure 3 (A) Figure 3 (B) Figure 4 as well as Figures 6 to 8 The structure of the protective component pasting device 10 will be described.

[0037] The protective component bonding device 10 has a protective component forming unit 12 for forming a sheet-like protective component 23 made of resin without a paste layer. Figure 3 (A) is a perspective view of the protective component forming unit 12, etc.

[0038] The protective component forming unit 12 has a worktable 14, which is made of a metal such as stainless steel and has a generally flat upper surface. A generally cylindrical pressing body 16, also made of a metal such as stainless steel, is disposed above the worktable 14.

[0039] The bottom surface of the pressing body 16 is generally flat. In addition, a resistance heating element (not shown) is provided inside the pressing body 16. A ball screw type up-and-down moving mechanism (not shown) is connected to the upper part of the pressing body 16 to move the pressing body 16 in the up-and-down direction.

[0040] When forming the protective component 23 using the protective component forming unit 12, firstly, particles 21 formed from a thermoplastic resin that can soften due to heat are disposed on the upper surface of the worktable 14. The thermoplastic resin is, for example, a polyolefin resin such as polyethylene, polypropylene, or polystyrene, or a polyester resin such as polyethylene terephthalate.

[0041] In this embodiment, after adjusting the temperature of the pressing body 16 to a predetermined temperature according to the material of the thermoplastic resin, the granules 21 are pressed onto the worktable 14 while being heated by the pressing body 16. At this time, the granules 21 are heated to a predetermined temperature exceeding the softening point (for example, a predetermined temperature of 160°C or higher and 180°C or lower in the case where the granules 21 are formed of polypropylene).

[0042] Thus, the particles 21 are softened or melted and shaped into a roughly circular form, and a protective component 23 is formed through a single heating and pressing process. In this embodiment, the protective component 23 is a resin sheet formed by a single-piece process. Figure 3 (B) is a three-dimensional view of protective component 23.

[0043] The protective member 23 has a predetermined diameter that is larger than the diameter of the wafer 11. In addition, the protective member 23 may vary depending on the conditions during its formation, but it has a predetermined thickness of, for example, 80 μm or more and 100 μm or less.

[0044] In this embodiment, the protective component 23 is formed from the particles 21 using the protective component forming unit 12 provided in the protective component bonding device 10. Therefore, it is not necessary to remove the protective component 23 from the roller body that is made of strips of protective components wound into a roller shape.

[0045] Typically, manufacturing rollers requires a relatively large industrial cleanroom. However, since rollers are not used in this embodiment, it is sufficient to control the air cleanliness of the relatively small space used when pressing the particles 21. Therefore, compared to using rollers, the manufacturing cost of each protective component 23 can be reduced.

[0046] Next, the protective component 23 is attached to the front side 11a of the wafer 11 using the protective component attaching unit 20 provided in the protective component attaching device 10. Figure 4 This is a partial cross-sectional side view of the protective component bonding unit 20, etc. The protective component bonding unit 20 has a concave lower body 20a, which is formed of a metal such as stainless steel and has an opening at the top.

[0047] An annular plate 20b capable of supporting the protective component 23 is provided inside the opening of the lower main body 20a. A disc-shaped chuck worktable (support worktable) 22 is provided below the annular plate 20b. The chuck worktable 22 has a metal frame 24a.

[0048] A disc-shaped porous plate 24b, formed of a porous material, is fixed to the upper part of the frame 24a. An annular groove 24c, centered on the center of the upper surface of the porous plate 24b, is formed on the porous plate 24b. The annular groove 24c has a predetermined diameter larger than the diameter of the wafer 11, serving as a cutting edge 34c used when cutting the protective component 23 (see reference). Figure 7 It functions by utilizing the tool relief groove.

[0049] The perforated plate 24b is connected to an attraction source (not shown) such as an injector via a flow path 24d formed in the frame 24a. The upper surfaces of the frame 24a and the perforated plate 24b are coplanar, forming a generally flat holding surface 22a.

[0050] An exhaust section 26 is provided at the bottom of the lower main body 20a. The exhaust section 26 has a cylindrical exhaust pipe (exhaust passage) 26a, one end of which is connected to the space inside the lower main body 20a. The other end of the exhaust pipe 26a is connected to an suction source 26b such as an injector.

[0051] A concave upper body 20c with an opening at the bottom is disposed above the lower body 20a. The upper body 20c has an opening with a shape substantially the same as the opening of the lower body 20a. The upper body 20c can be raised and lowered relative to the lower body 20a. When the upper body 20c is disposed on the lower body 20a with the openings overlapping, a space isolated from the outside is formed.

[0052] An exhaust section 28 is provided at the top of the upper body 20c. The exhaust section 28 has a cylindrical exhaust pipe (exhaust passage) 28a, one end of which is connected to a space inside the upper body 20c. The other end of the exhaust pipe 28a is connected to an attraction source 28b such as an injector.

[0053] An air supply section 30 is provided at a different position than the exhaust section 28 in the top of the upper main body 20c. The air supply section 30 has a cylindrical air supply pipe (air supply path) 30a with one end connected to the space inside the upper main body 20c. In addition, a solenoid valve 30b is provided on the air supply pipe 30a.

[0054] In addition, although Figure 4 The middle part is omitted, but a disc-shaped pressing body 32 is arranged in the recess of the upper main body 20c (see reference). Figure 6 The pressing body 32 is made of a metal such as stainless steel and has a generally flat lower surface 32a.

[0055] A resistance heating element 32b is provided inside the pressing body 32. A ball screw type up-and-down moving mechanism (not shown) is connected to the upper part of the pressing body 32 to move the pressing body 32 in the up-and-down direction.

[0056] A cutting mechanism 34 is provided on the outer side of the lower main body 20a (see reference). Figure 7 The cutting mechanism 34 can be moved upwards from the lower body 20a via a moving mechanism (not shown). The cutting mechanism 34 has a rod-shaped arm 34a arranged substantially parallel to the holding surface 22a.

[0057] An output shaft 34b, such as an electric motor, is arranged approximately parallel to the direction perpendicular to the holding surface 22a between one end of the arm 34a and the other end. The lower part of the output shaft 34b is connected to the arm 34a. Additionally, a cutting edge 34c is connected to one end of the arm 34a.

[0058] A thickness measuring unit 36 ​​is disposed near the protective component pasting unit 20 (see reference). Figure 8 The thickness measuring unit 36 ​​has a thickness measuring device 36a for measuring the thickness of the protective component 23. The thickness measuring device 36a is, for example, a spectroscopic interferometer laser displacement meter.

[0059] The thickness information of the protective component 23, measured by the thickness measuring device 36a, is transmitted through the transmission unit 38 (see reference). Figure 2 The transmitting unit 38 transmits information about the thickness of the protective component 23 to the outside of the protective component pasting device 10 via wireless LAN (Local Area Network), wired LAN, or the like.

[0060] For example, when using a wireless LAN, the transmitting unit 38 is a transmitter that includes a signal source, modulation circuit, amplifier, antenna, etc., and sends information about the thickness of the protective component 23 to the receiving unit 90 of the grinding apparatus 50, which will be described later.

[0061] The operation of the sending unit 38, etc., is controlled by the control unit 40. In addition to controlling the sending unit 38, the control unit 40 also controls the operation of the protective component forming unit 12, the protective component pasting unit 20, the thickness measuring unit 36, etc.

[0062] The control unit 40 may be composed of a computer, which includes a processor (processing device) represented by a CPU (Central Processing Unit), main storage devices such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), and ROM (Read Only Memory), as well as auxiliary storage devices such as flash memory, hard disk drives, and solid-state drives.

[0063] The auxiliary storage device stores software containing a prescribed program. By following this software, the processor and other components are activated, thus realizing the function of the control unit 40. Next, refer to... Figure 9 The grinding apparatus 50 will be described.

[0064] The grinding apparatus 50 has a disc-shaped chuck table 52. The chuck table 52 includes a disc-shaped frame made of ceramic or the like. A disc-shaped recess is formed in the upper part of the frame, and a generally disc-shaped porous plate made of a porous material is fixed in the recess.

[0065] The perforated plate is connected to an attraction source (not shown) such as an ejector via a flow path (not shown) formed in the frame. When the attraction source is activated, a negative pressure is generated on the upper surface of the perforated plate. The upper surface of the frame and the upper surface of the perforated plate are approximately the same plane, and function as a holding surface 52a for attracting and holding the wafer 11, etc.

[0066] A rotary drive source (not shown) with an electric motor or the like is provided below the chuck table 52. The output shaft of the rotary drive source is connected to the lower part of the chuck table 52. When the rotary drive source is activated, the chuck table 52 rotates around the output shaft.

[0067] A grinding feed unit 54 is disposed above the chuck table 52. The grinding feed unit 54 is mounted on a prism-shaped column (not shown) that is disposed approximately vertically to the base (not shown).

[0068] The grinding feed unit 54 has a pair of guide rails 56 fixed to one side of the column and substantially parallel to the vertical direction. A movable plate 58 is slidably mounted on the pair of guide rails 56.

[0069] A nut portion 60 is provided on the back side (column side) of the movable plate 58. A ball screw 62, which is arranged substantially parallel to a pair of guide rails 56, is rotatably connected to the nut portion 60.

[0070] A pulse motor 64 is connected to the upper end of the ball screw 62. If the ball screw 62 is rotated by the pulse motor 64, the moving plate 58 moves along the guide rail 56 in the vertical direction (up and down direction).

[0071] A grinding unit 68 is fixed to the front side of the moving plate 58. The grinding unit 68 has a cylindrical holding member 70 fixed to the moving plate 58. Inside the holding member 70 is a cylindrical spindle housing 72 arranged approximately parallel to the vertical direction.

[0072] A portion of a cylindrical spindle 74, arranged approximately parallel to the vertical direction, is housed within the spindle housing 72 in a rotatable state. An electric motor (not shown) is mounted at the upper end of the spindle 74.

[0073] The lower end of the spindle 74 protrudes downward beyond the lower surface of the retaining member 70, and a disc-shaped wheel mount 76 is fixed to the upper surface of the lower end of the spindle 74. An annular grinding wheel 78 is mounted on the lower surface of the wheel mount 76.

[0074] The grinding wheel 78 includes: an annular grinding wheel base 78a, which is formed of a metal material such as stainless steel; and a plurality of grinding tools 78b, which are mounted on the lower surface of the grinding wheel base 78a. The plurality of grinding tools 78b are arranged in a ring along the circumference of the lower surface of the grinding wheel base 78a in such a way that gaps are provided between adjacent grinding tools 78b.

[0075] Each grinding wheel 78b is formed by mixing abrasive grains such as diamond and cBN (cubic boron nitride) into a bonding material such as metal, ceramic, or resin. Furthermore, there are no particular limitations on the materials of the bonding material and the abrasive grains; they can be appropriately selected according to the specifications of the grinding wheel 78b.

[0076] A nozzle 82 is disposed above the holding surface 52a for supplying grinding water 80, such as pure water, to the contact area between the grinding wheel 78b and the wafer 11. In addition, a thickness gauge 86 for measuring the thickness of the wafer 11 or the like during grinding is disposed in the outer periphery of the holding surface 52a in a region away from the grinding unit 68.

[0077] The thickness measuring device 86 has a first height gauge 86a, the front end of which contacts the holding surface 52a for measuring the height of the holding surface 52a. Additionally, the thickness measuring device 86 has a second height gauge 86b, the front end of which contacts the back surface 11b of the wafer 11 held by the holding surface 52a for measuring the height of the back surface 11b.

[0078] The total thickness (i.e., overall thickness) of the wafer 11 and the protective component 23 during grinding is measured by calculating the difference between the height of the holding surface 52a and the height of the back surface 11b. The operation of the chuck table 52, the grinding feed unit 54, the grinding unit 68, etc., is controlled by the control unit 88.

[0079] The control unit 88 may be composed of a computer, which includes a processor (processing device) 88a represented by a CPU, main storage devices (not shown) such as DRAM, SRAM, and ROM, and auxiliary storage devices 88b such as flash memory, hard disk drive, and solid-state drive.

[0080] The auxiliary storage device 88b stores software containing a prescribed program. By following this software, the processor 88a and the like operate, thus realizing the function of the control unit 88. The auxiliary storage device 88b includes a recording unit 88c having a prescribed recording area.

[0081] The recording unit 88c records information such as the thickness of the protective component 23 measured by the thickness measuring unit 36, the total thickness of the wafer 11 with the protective component 23, and the target finished thickness of the wafer 11 after grinding.

[0082] Information regarding the thickness of the protective component 23, measured by the thickness measuring unit 36, is transmitted from the transmitting unit 38 of the protective component pasting device 10 and received by the receiving unit 90 of the grinding device 50. For example, in the case of using a wireless LAN, the receiving unit 90 is a receiver having an antenna, amplifier, demodulation circuit, etc.

[0083] Next, refer to Figure 3 (A) to Figure 10 The processing method of wafer 11 using protective component bonding device 10 and grinding device 50 is described. Figure 10 This is a flowchart of the processing method for wafer 11.

[0084] First, use Figure 3 The protective component forming unit 12 shown in (A) softens or melts the particles 21 formed of thermoplastic resin by heating and pressing them, forming them into a roughly circular shape, thus forming a sheet-like protective component 23 (see reference). Figure 3 (B) (Protective component forming step S10).

[0085] After the protective component formation step S10, the protective component bonding unit 20 is used to make the protective component 23 closely contact the front side 11a side of the wafer 11 (protective component contact step S20). In the protective component contact step S20, firstly, the back side 11b side of the wafer 11 is supported by the chuck stage 22, and the back side 11b side is attracted and held by the holding surface 22a.

[0086] Then, a sheet conveying device (not shown) with multiple suction pads is used to convey the protective component 23 and place it on the annular plate 20b. At this time, as Figure 4 As shown, the protective component 23 is supported by the annular plate 20b in a manner that does not contact the front side 11a.

[0087] For example, by pressing the outer periphery of the protective member 23 against the annular plate 20b using a pressing member (not shown), the protective member 23 is supported in a manner that does not contact the front surface 11a. Alternatively, the opening of the annular plate 20b can be reduced so that the diameter defined by the inner periphery of the annular plate 20b is slightly larger than that of the wafer 11, thereby replacing the use of the pressing member.

[0088] Next, after the upper body 20c is placed on the lower body 20a to form a space isolated from the outside, the suction sources 26b and 28b are activated respectively. As a result, the first space 20d formed by the protective member 23 and the lower body 20a and the second space 20e formed by the protective member 23 and the upper body 20c are depressurized to about 1000 Pa respectively.

[0089] After decompression, the operation of suction sources 26b and 28b is stopped. While maintaining the pressure in the first space 20d at approximately 1000 Pa, the upper main body 20c is opened to the atmosphere by opening the solenoid valve 30b. As a result, the air pressure in the recess of the upper main body 20c rises sharply to atmospheric pressure, and the pressure difference presses the protective component 23 toward the front 11a side.

[0090] The protective component 23 is deformed in a manner that mimics the concave-convex shape of the front side 11a, thereby making close contact with the front side 11a (protective component close contact step S20). Figure 5 This diagram illustrates the situation where the protective component 23 is brought into close contact with the front side 11a using the air pressure difference.

[0091] After the protective component sealing step S20, while the heating element 32b is heated, the pressing body 32 is moved downwards, and the lower surface 32a presses the protective component 23 against the front side 11a (see reference). Figure 6 ).

[0092] For example, the pressing body 32 is set to a specified temperature of 50°C or higher and 120°C or lower, and pressed for about 30 seconds with a specified pressing pressure of 0.2 MPa or higher and 0.8 MPa or lower. As a result, the protective member 23 is attached to the front side 11a, forming a wafer 11 with the protective member 23 (wafer formation step S30 with protective member).

[0093] In the wafer formation step S30 with the protective member, the protective member 23 is softened by heating, thus enabling the protective member 23 to make closer contact with the front side 11a compared to the case without heating. After the pressing body 32 retracts, the wafer 11 with the protective member 23 is cooled.

[0094] Compared to before the wafer formation step S30 with protective components, the thickness of the protective component 23 is sometimes reduced by more than 5% and less than 20% (e.g., about 10%). After the wafer formation step S30 with protective components, as... Figure 7 As shown, the protective component 23 is cut into approximately the same diameter as the wafer 11 using the cutting mechanism 34 (protective component cutting step S40).

[0095] In the protective component cutting step S40, a cut 23a of a predetermined diameter is formed on the protective component 23 (see reference). Figure 8 The protective component 23 is cut into a circle. After the protective component cutting step S40, the thickness of the protective component 23 in the wafer 11 with the protective component 23 is measured using the thickness measuring unit 36 ​​(thickness measurement step S50). In the thickness measurement step S50, the thickness of more than one part of the protective component 23 is measured.

[0096] In this embodiment, after measuring the thickness of multiple portions of the protective member 23 using the thickness measuring unit 36, the control unit 40 calculates the arithmetic mean of the thicknesses of these multiple portions, and uses the average thickness as the representative thickness of the protective member 23. However, the method for calculating the representative thickness is not limited to the arithmetic mean. Information regarding the thickness of the protective member 23 is recorded in the recording unit 88c of the grinding apparatus 50 via the transmitting unit 38 and the receiving unit 90.

[0097] By performing the thickness measurement step S50, information on the thickness of the protective component 23 after the wafer formation step S30 and before the grinding step S60 can be obtained. This information on the thickness of the protective component 23 becomes useful information for tracking all processes in the device chip manufacturing process and for analyzing the causes of defects.

[0098] After the thickness measurement step S50, the wafer 11 with the protective member 23 is transported to the grinding apparatus 50 using a wafer transport unit (not shown). The wafer 11 with the protective member 23 is attracted and held by the holding surface 52a of the chuck stage 52 with its back side 11b facing upward.

[0099] In this state, while measuring the total thickness of the wafer 11 with protective component 23 using thickness measuring device 86, grinding unit 68 is fed toward holding surface 52a using grinding feed unit 54, and grinding is performed on back side 11b until wafer 11 reaches the target finished thickness (grinding step S60).

[0100] In particular, in the grinding step S60, the control unit 88 subtracts the representative thickness of the protective component 23 measured in the thickness measurement step S50 from the total thickness of the wafer 11 with the protective component 23, calculates the thickness of the wafer 11 in real time, and adjusts the grinding feed to achieve the target finished thickness.

[0101] In this embodiment, even if the thickness of the protective member 23 changes compared to the wafer formation step S30 with the protective member, since grinding is performed based on a measurement of the changed thickness of the protective member 23, the grinding feed rate can be adjusted in the grinding step S60 according to the changed thickness of the protective member 23. Therefore, the impact of changes in the thickness of the protective member 23 on the grinding (processing) conditions can be reduced.

[0102] Furthermore, in the protective member contact step S20 of the first embodiment, the protective member 23 is disposed on the wafer 11, but the wafer 11 can also be disposed on the protective member 23. In addition, a heating element (not shown) can also be provided in the chuck stage 22, and in the wafer forming step S30 with the protective member, the wafer 11 can be pressed downward while at least one of the wafer 11 and the protective member 23 is heated.

[0103] Next, the second embodiment will be described. In the second embodiment, the above-described S10 to S60 are performed using a processing apparatus 92 having a protective component bonding device 110 and a grinding device 150. Figure 11 This is a block diagram showing the outline of the processing apparatus 92.

[0104] The protective component bonding device 110 corresponds to the protective component bonding device 10 except for the sending unit 38 and the control unit 40, and the grinding device 150 corresponds to the grinding device 50 except for the receiving unit 90 and the control unit 88. The processing device 92 has a control unit 94, which has the functions of both the control unit 40 of the protective component bonding device 10 and the control unit 88 of the grinding device 50.

[0105] The control unit 94 may be composed of a computer, which includes a processor (processing device) 94a represented by a CPU, main storage devices (not shown) such as DRAM, SRAM, and ROM, and auxiliary storage devices 94b such as flash memory, hard disk drive, and solid-state drive.

[0106] The auxiliary storage device 94b includes a recording unit 94c. The recording unit 94c corresponds to the recording unit 88c in the first embodiment. The control unit 94 records the thickness (e.g., representative thickness) of the protective member 23 measured by the thickness measuring unit 36 ​​in the recording unit 94c.

[0107] Furthermore, the control unit 94 calculates the thickness of the wafer 11 in real time by subtracting the representative thickness of the protective member 23 from the total thickness of the wafer 11 with the protective member 23, and adjusts the grinding feed to make the wafer 11 reach the target finished thickness. Therefore, similar to the first embodiment, the influence of variations in the thickness of the protective member 23 on the grinding (processing) conditions can be reduced.

[0108] Next, the third embodiment will be described. In the first and second embodiments, a sheet-like protective component 23 made of thermoplastic resin and without a paste layer is formed within the protective component bonding device 10 by using the protective component forming unit 12.

[0109] However, the protective component adhesive device 10 may not necessarily have a protective component forming unit 12. In this case, a sheet-like protective component (not shown) is used, which has: a substrate layer formed of thermoplastic resin; and a paste layer disposed on the substrate layer in a generally circular area corresponding to the front side 11a or on the outer periphery of the substrate layer.

[0110] In the third embodiment, the protective member formation step S10 is omitted during the processing of the wafer 11. In the protective member bonding step S20, the edge of the protective member 23 is disposed on the annular plate 20b with the paste layer facing the front side 11a. Then, the paste layer is bonded to the front side 11a using a pressure difference. Furthermore, steps S30 to S60 are performed in the same manner as in the first embodiment.

[0111] However, in the wafer formation step S30 with the protective component, a cylindrical roller with an internal resistance heating element is used instead of the pressing body 32. For example, the roller is set to a specified temperature of 50°C or higher and 120°C or lower, and with the side of the roller pressed against the protective component 23, the roller is rolled and moved across the entire front side 11a for about 5 seconds.

[0112] After the rollers are retracted, the wafer 11 with the protective member 23 is cooled, but the thickness of the protective member 23 after cooling is sometimes reduced by more than 5% and less than 20% (e.g., about 10%) compared to before the wafer forming step S30 with the protective member.

[0113] However, in the third embodiment, a thickness measurement step S50 is also performed to measure the thickness of the protective member 23 of the wafer 11 with the protective member 23. Then, in the subsequent grinding step S60, the control unit 88 of the grinding apparatus 50 calculates the thickness of the wafer 11 in real time by subtracting the representative thickness of the protective member 23 from the total thickness of the wafer 11 with the protective member 23, and adjusts the grinding feed to achieve the target finished thickness.

[0114] Therefore, similar to the first embodiment, the impact of the change in the thickness of the protective member 23 caused by the wafer formation step S30 with the protective member on the grinding (processing) conditions can be reduced. Furthermore, the structure, method, etc., of the above embodiments can be implemented with appropriate modifications without departing from the purpose of the present invention.

Claims

1. A wafer processing method of processing a wafer having a device on a front surface side, characterized by comprising: a wafer processing method having the steps of: a protective member close contact step of supporting a protective member formed of a resin capable of being softened by heat by a ring-shaped plate arranged around the wafer, and making the protective member close contact to the wafer by means of an opening portion of the ring-shaped plate having the opening portion defined by an inner peripheral end, by a pressure difference; a wafer with protective member forming step of, after the protective member close contact step, pressing the protective member toward the front surface side of the wafer while heating the protective member, thereby sticking the protective member to the front surface side of the wafer to form a wafer with protective member; a thickness measurement step of measuring a thickness of the protective member of the wafer with protective member; and a grinding step of holding the wafer with protective member by a holding surface of a chuck table, and grinding a back surface side of the wafer until the wafer becomes a target finished thickness, wherein in the grinding step, the thickness of the wafer is calculated from a total thickness of the wafer with protective member by subtracting the thickness of the protective member measured in the thickness measurement step, and the back surface side of the wafer is ground.

2. The wafer processing method according to claim 1, characterized in that the protective member used in the wafer with protective member forming step is a single piece of sheet formed by pressing while heating a thermoplastic resin capable of being softened by heat.

3. The wafer processing method according to claim 1 or 2, characterized in that the wafer processing method further has a protective member forming step of, before the protective member close contact step, softening or melting a pellet to form the protective member having a larger diameter than the wafer.

4. A protective member sticking device that sticks a protective member to a front surface side of a wafer having a device on the front surface side, characterized by comprising: a protective member sticking unit having a holding table and a pressing body, the protective member sticking unit using the pressing body and holding table to stick the protective member to the front surface side of the wafer to form a wafer with protective member by pressing the protective member toward the front surface side of the wafer while heating the protective member formed of a resin capable of being softened by heat; a thickness measurement unit having a thickness measurer and measuring a thickness of the protective member in the wafer with protective member; and a transmission portion for transmitting information of the thickness of the protective member measured by the thickness measurement unit to an outside of the protective member sticking device, wherein the protective member sticking unit has: a concave lower body provided with the holding table; a ring-shaped plate arranged inside a first opening portion of the lower body to support the protective member; a first exhaust portion provided to the lower body; a concave upper body arranged above the lower body; and a second exhaust portion and a gas supply portion provided to the upper body. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The protective member sticking unit makes the protective member adhere to the wafer by using a pressure difference with the aid of the second opening portion of the annular plate having the second opening portion defined by an inner peripheral end, and then makes the protective member adhere to the wafer by heating and pressing.

5. A processing apparatus having a protective member sticking device that sticks a protective member to a front surface side of a wafer having a device on the front surface side, and a grinding device that grinds the wafer to which the protective member is stuck on the front surface side, characterized by The protective member sticking device includes: a protective member sticking unit having a support table and a pressing body, the protective member sticking unit using the pressing body and support table to heat the protective member formed of a resin that can be softened by heat while pressing the protective member toward the front surface side of the wafer, thereby sticking the protective member to the front surface side of the wafer to form a wafer with a protective member; a thickness measuring unit having a thickness gauge and measuring a thickness of the protective member in the wafer with the protective member; and a transmission section for transmitting information on the thickness of the protective member measured by the thickness measuring unit to the grinding device, The protective member sticking unit has: a concave lower body provided with a support table; an annular plate disposed inside a first opening portion of the lower body to support the protective member; a first exhaust portion provided to the lower body; a concave upper body disposed above the lower body; and a second exhaust portion and a gas supply portion provided to the upper body, The protective member sticking unit makes the protective member adhere to the wafer by using a pressure difference with the aid of the second opening portion of the annular plate having the second opening portion defined by an inner peripheral end, and then makes the protective member adhere to the wafer by heating and pressing. The grinding device includes: a chuck table that holds the wafer with the protective member; a grinding unit having a cylindrical spindle and a circular ring-shaped grinding wheel mounted to a lower end portion of the spindle to grind a back surface side of the wafer held by the chuck table; and a grinding feed unit that feeds the grinding unit toward the chuck table, The processing apparatus further has a control section having a processor and controlling an operation of the grinding feed unit, The control section has a recording section that records information on the thickness of the protective member measured by the thickness measuring unit, information on a total thickness of the wafer with the protective member, and information on a target finished thickness of the wafer after grinding, The thickness of the wafer is calculated by subtracting the thickness of the protective member from the total thickness of the wafer with the protective member, and the back surface side of the wafer is ground by controlling the operation of the grinding feed unit, thereby grinding the wafer until the wafer reaches the target finished thickness.

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