Protective member forming apparatus

Abstract

To provide a protective member forming device, which is capable of determining whether a desired protective member can be formed and is capable of forming a wafer with a desired protective member formed thereon.SOLUTION: A protective member forming device (1) includes: a reporting section (42) which reports an error by a load value detected by a load detecting part (22), a load being caused when a liquid resin (31) supplied on a sheet (30) is pressed by a wafer (W) held by a holding part (20), in one of the cases where it is detected that the thickness of the wafer (W) does not match a preset thickness, where it is detected that the supply amount of the liquid resin supplied on the sheet (30) does not match a preset amount, where a lowering speed to lower the holding part (20) is different from a preset speed, or where the load detecting part (22) fails; and a control section (43) which cures the liquid resin on the sheet (30) when the reporting section (42) reports an alarm.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a protective member forming apparatus.

Background Art

[0002] When performing grinding or the like on a wafer, a protective member for protecting the entire one surface of the wafer is formed. The protective member forming apparatus for forming the protective member supplies a liquid resin onto a sheet placed on a table, lowers a holding portion that holds the wafer above the table, spreads the liquid resin with the wafer held by the holding portion, and then cures the liquid resin to form a protective member composed of a resin and a sheet on the entire one surface of the wafer.

[0003] The liquid resin for forming the protective member is one that cures by applying a specific external stimulus, such as an ultraviolet curable resin or a thermosetting resin. For example, in the case of an ultraviolet curable liquid resin, it is cured by irradiating ultraviolet rays for a preset time.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the process of forming the protective member, there is a problem that a wafer with a desired protective member cannot be obtained because the protective member is formed in a state where set values such as wafer thickness, supplied resin amount, or the lowering speed of the holding portion are different, or due to error factors such as a failure of the apparatus.

[0006] For example, suppose the error is due to wafer thickness. If a wafer thicker than the preset thickness is formed, the liquid resin will be pressed too hard, causing it to overflow from the outer edge of the wafer and resulting in a thinner resin layer. Conversely, if the wafer is thinner than the preset thickness, there will be insufficient force to press the liquid resin, preventing it from spreading across the entire underside of the wafer. Thus, if the wafer thickness differs from the preset thickness, it will be impossible to form a protective layer of the desired thickness, and the desired wafer will not be obtained.

[0007] Therefore, it was desirable to determine whether or not it is possible to form the desired protective member during the protective member formation process, and to efficiently obtain wafers with the desired protective member formed on them.

[0008] The present invention has been made in view of the above, and aims to provide a protective member forming apparatus that can determine whether or not it is possible to form a desired protective member, and can efficiently form a wafer on which the desired protective member has been formed. [Means for solving the problem]

[0009] One aspect of the present invention comprises a table on which a sheet is placed, a sheet transport unit for transporting the sheet to the table, a resin supply unit for supplying liquid resin onto the sheet placed on the table, a holding unit for holding a wafer above the table, a lifting mechanism for raising and lowering the table and the holding unit relative to each other, a load detection unit for detecting the load caused by bringing the table and the holding unit closer together to a predetermined distance and pressing the wafer held by the holding unit against the liquid resin on the sheet, and below the wafer on A curing mechanism that hardens the spread liquid resin, A transport mechanism for transporting a wafer with the cured liquid resin and the sheet attached to its lower surface, and a recovery unit for recovering the wafer with the resin and the sheet attached to its lower surface, The wafer thickness does not match the preset thickness. Ito If the amount of liquid resin supplied onto the sheet does not match the amount set in advance Ito When the descent speed of the holding unit differs from a preset speed, or when the load detection unit malfunctions, the liquid resin supplied onto the sheet is pressed by the wafer held by the holding unit, and the load value detected by the load detection unit is... If the value does not fall within the range from the predetermined upper limit to the predetermined lower limit An alarm unit that issues an error, and when the alarm unit issues an error, the sheet and the space between the lower surface of the wafer held in the holding part It comprises a control unit for curing the liquid resin, The wafer, to which the cured liquid resin and the sheet are attached, is transported to the recovery section by the transport mechanism. It is characterized by the following: [Effects of the Invention]

[0011] According to the protective member forming apparatus of the present invention, it is possible to determine whether a desired protective member has been formed and to form a wafer on which the desired protective member has been formed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view showing the protective member forming apparatus of this embodiment. [Figure 2] This is a cross-sectional view of a part of a protective member forming apparatus. [Figure 3] This is an explanatory diagram showing the sheet loading process in a protective member forming apparatus. [Figure 4] This is an explanatory diagram showing the liquid resin supply process in a protective member forming apparatus. [Figure 5] This is an explanatory diagram showing the wafer holding process in a protective member forming apparatus. [Figure 6] This is an explanatory diagram showing the spreading process in a protective member forming apparatus. [Figure 7] This is an explanatory diagram showing the curing process in a protective member forming apparatus. [Figure 8] This graph illustrates an example of how the load detection unit of this embodiment issues an error based on the detected load value. [Modes for carrying out the invention]

[0013] The liquid resin curing determination method and protective member forming apparatus according to this embodiment will be described below with reference to the attached drawings. Figures 1 and 2 show the whole and a part of the protective member forming apparatus according to this embodiment. Figures 3 to 7 are diagrams illustrating each process performed by the protective member forming apparatus. Figure 8 is a graph illustrating an example of how the load detection unit of this embodiment issues an error based on the detected load value.

[0014] The X, Y, and Z axes shown in each figure are perpendicular to each other. The X and Y axes are approximately horizontal, while the Z axis is vertical. In each figure, of the two arrows indicating the X axis, the side with the letter X is considered the left, and the side without the letter X is considered the right. Of the two arrows indicating the Y axis, the side with the letter Y is considered the front, and the side without the letter Y is considered the back. Of the two arrows indicating the Z axis, the side with the letter Z is considered the top, and the side without the letter Z is considered the bottom.

[0015] The protective member forming apparatus 1 shown in Figure 1 is an example of an apparatus that forms a protective member by curing a liquid resin, which has been spread over the entire surface of one side of a wafer W, by applying an external stimulus. In Figure 1, the external housing 10 of the protective member forming apparatus 1 is shown by a dashed line, and the internal components of the external housing 10 are shown in a transparent view. Of the wafer W, the side facing upwards during processing in the protective member forming apparatus 1 is called the upper surface Wa, and the side facing downwards is called the lower surface Wb.

[0016] As will be described later, in the protection member forming apparatus 1, a liquid resin 31 (see FIGS. 2, 4, and 5) is supplied onto a sheet 30 placed on a sheet placement table 16, and the wafer W held by the wafer holding portion 20 is operated to be pressed against the liquid resin 31 from above the sheet placement table 16. When the lower surface Wb of the wafer W is pressed toward the sheet 30, the liquid resin 31 is spread between the wafer W and the sheet 30 (see FIG. 6). In this state, an external stimulus is applied to the liquid resin 31 to cure it, and the cured resin and the sheet 30 form a protection member 32 (see FIG. 7). Further, the wafer W to which the cured resin and the sheet 30 are attached may be referred to as a workpiece.

[0017] Such a series of operations is performed under the control of a management unit 40 (FIG. 1) that centrally controls the protection member forming apparatus 1. For the operations of each part described below, when the subject of control is not specified, it is assumed that the operation is controlled by a control signal sent from the management unit 40.

[0018] The wafer W is, for example, a disk-shaped as-cut wafer cut from an ingot such as columnar silicon. Note that the wafer W is not limited to an as-cut wafer before device formation, and may be a device wafer after device formation or the like.

[0019] The protection member forming apparatus 1 includes a cassette storage portion 11 at one end side (left end portion) in the X-axis direction of the external housing 10. The cassette storage portion 11 has upper and lower two-stage storage spaces 111 and 112. In the upper storage space 111, a carry-in side cassette C1 for storing a plurality of wafers W before the protection member 32 is formed is placed. In the lower storage space 112, a carry-out side cassette C2 for storing the wafer W after the protection member 32 is formed is placed. The cassette C1 and the cassette C2 can each store a plurality of wafers W.

[0020] The cassette storage section 11 is equipped with a recovery section C3 that recovers the wafer when the alarm unit 42 (described later) issues an error. The recovery section C3 recovers and stores the wafer W that has triggered the error. Alternatively, the discharge-side cassette C2, which stores the wafer W after the protective member 32 has been formed, may be used as the recovery section C3.

[0021] A temporary placement table 13 and a sheet cutting table 14 are provided on the right side of the cassette storage section 11 in the X-axis direction. The temporary placement table 13 is located on the upper side, and the sheet cutting table 14 is located on the lower side. The temporary placement table 13 is provided with a wafer detection unit 131 that detects the center position and orientation of the wafer W before the protective member 32 is formed. The sheet cutting table 14 is provided with a sheet cutter 141 that cuts the sheet 30 attached to the wafer W along the outer shape of the wafer W.

[0022] A first wafer transport mechanism 12 is provided on the front side in the Y-axis direction relative to the temporary storage table 13 and the sheet cutting table 14, for loading and unloading wafers W to and from each cassette C1 and C2. The first wafer transport mechanism 12 includes a robot hand 122 supported on a base 121, and the base 121 is supported so as to be movable along a pair of guide rails 123 extending in the Y-axis direction. The base 121 has a screw portion (not shown) that screws into a ball screw 124 extending in the Y-axis direction. When the ball screw 124 is rotated by the driving force of the motor, the base 121 moves in the Y-axis direction.

[0023] The first wafer transport mechanism 12 transports wafers W between the cassette storage section 11, the temporary storage table 13, and the sheet cutting table 14 by moving the base 121 in the Y-axis direction and operating the robot hand 122. More specifically, the first wafer transport mechanism 12 can remove wafers W before the protective member 32 is formed from cassette C1 in the storage space 111 and place them on the temporary storage table 13. The first wafer transport mechanism 12 can also remove wafers W after the protective member 32 has been formed from the sheet cutting table 14 and place them in cassette C2 in the storage space 112.

[0024] The protective member forming apparatus 1 is equipped with a base 15 on the right side in the X-axis direction relative to the temporary placement table 13 and the sheet cutting table 14. A sheet placement table 16 is provided on the base 15. The sheet placement table 16 is made of a translucent material such as quartz glass and is formed in a disc shape. The upper surface of the sheet placement table 16 is a flat sheet support surface 161 for placing the sheet 30.

[0025] The sheet transport unit 17 transports and places the sheet 30 onto the sheet support surface 161 of the sheet placement table 16. The sheet transport unit 17 includes a sheet supply unit 171 that supports the rolled sheet 30, an arm 172 that is movable in the X-axis direction, and a clamp unit 173 attached to the side of the arm 172. The sheet transport unit 17 holds the rolled sheet 30 supported by the sheet supply unit 171 with the clamp unit 173, and places the sheet 30 onto the sheet support surface 161 of the sheet placement table 16 by moving the arm 172 in the X-axis direction and pulling the sheet 30.

[0026] The sheet 30 is made of a light-transmitting material. For example, a film made of polyethylene terephthalate can be used as the sheet 30. However, a sheet 30 made of a material other than this may also be used.

[0027] Multiple suction holes (not shown) are formed in the sheet support surface 161 of the sheet placement table 16. The suction holes are connected to a suction source 162 (see Figure 2). By operating the suction source 162 and applying suction force to the suction holes, the sheet 30 placed on the sheet support surface 161 is held in place by suction to the sheet support surface 161.

[0028] Near the sheet support table 16, a resin supply unit 18 is provided to supply a predetermined amount of liquid resin 31 to the upper surface of the sheet 30 on the sheet support surface 161. The resin supply unit 18 comprises a dispenser 181 connected to a tank 184 provided in the base 15, and a resin supply nozzle 183 to which a connecting pipe 182 extending from the dispenser 181 connects. The resin supply nozzle 183 is rotatable about an axis facing the Z-axis, and can be positioned above the sheet support table 16 or retracted from above the sheet support table 16.

[0029] Liquid resin 31 stored in tank 184 is supplied by dispenser 181 via connecting pipe 182, and the liquid resin 31 is dripped downward from resin supply nozzle 183. The amount of liquid resin 31 supplied from resin supply nozzle 183 can be adjusted by dispenser 181.

[0030] The liquid resin 31 has the property of hardening in response to external stimuli. In this embodiment, an ultraviolet-curing resin that hardens upon irradiation with ultraviolet light is used.

[0031] A column 19 is provided on the left side of the sheet mounting table 16 in the X-axis direction, projecting upward from the base 15. The column 19 is equipped with a lifting mechanism 21 that moves the wafer holding section 20 in the Z-axis direction to move it closer to and further away from the sheet mounting table 16. The lifting mechanism 21 includes a pair of guide rails 211 extending in the Z-axis direction, a lifting table 212 supported so as to be movable in the Z-axis direction relative to the pair of guide rails 211, and a ball screw 213 (see Figure 2) extending in the Z-axis direction and screwed into a threaded section 215 (see Figure 2) of the lifting table 212. When the ball screw 213 is rotated by the driving force of the motor 214, the lifting table 212 moves in the Z-axis direction along the pair of guide rails 211. When the ball screw 213 is rotated in a first direction, the lifting table 212 moves downward, and when the ball screw 213 is rotated in a second direction, the lifting table 212 moves upward.

[0032] The wafer holder 20 is supported by a lifting table 212, and the wafer holder 20 moves in the Z-axis direction in conjunction with the lifting table 212. The wafer holder 20 includes a disc-shaped holding table 201. As shown in Figures 2, 5 to 7, a disc-shaped porous member 202 is provided on the lower surface of the holding table 201. The lower surface of the porous member 202 is the wafer holding surface 203 located above the sheet mounting table 16. The wafer holding surface 203 is a surface that is substantially parallel to the sheet support surface 161 of the sheet mounting table 16.

[0033] As shown in Figure 2, the porous member 202 is connected to the suction source 205 via the suction passage 204. By operating the suction source 205 and applying suction force to the porous member 202, the upper surface Wa of the wafer W can be held by the wafer holding surface 203 through suction.

[0034] With the upper surface Wa of the wafer W held by the wafer holding surface 203 of the wafer holding section 20 (Figure 2), when the wafer holding section 20 is lowered by the lifting mechanism 21, the lower surface Wb of the wafer W comes into contact with the liquid resin 31 supplied onto the sheet 30, and the liquid resin 31 is spread out by the force of lowering the wafer W.

[0035] As shown in Figures 5 to 7, the wafer holding unit 20 is equipped with a load detection unit 22. Multiple load sensors 221 are provided at different positions on the upper surface of the holding table 201, and these load sensors 221 constitute the load detection unit 22. The load detection unit 22 can detect the vertical load (in the Z-axis direction) applied to the lower surface Wb of the wafer W based on the outputs of the multiple load sensors 221.

[0036] Multiple load sensors 221 are positioned at arbitrary locations that can appropriately detect the load applied to the lower surface Wb of the wafer W. For example, three load sensors 221 are positioned to surround a virtual central axis that extends in the Z-axis direction through the center of the holding table 201.

[0037] A curing mechanism 23 is provided at the bottom of the sheet support table 16 to cure the liquid resin 31 that has been dripped onto the sheet 30 on the sheet support surface 161 by applying external stimuli. The curing mechanism 23 is equipped with a plurality of ultraviolet irradiation units 231 capable of emitting ultraviolet UV (Figure 7), and cures the liquid resin 31 by irradiating it with ultraviolet UV through the light-transmitting sheet support table 16 and sheet 30.

[0038] Furthermore, an imaging unit 24 is provided at the bottom of the sheet mounting table 16 to image the direction of the sheet support surface 161. The imaging unit 24 is a camera having a lens and an image sensor, and has an imaging range that allows it to image the outer edge of the liquid resin 31 being spread out on the sheet 30 on the sheet support surface 161, and the entire lower surface Wb of the wafer W when the liquid resin 31 is being spread out, from below the sheet support surface 161.

[0039] As shown in Figure 1, a second wafer transfer mechanism 25 is provided on the front side in the Y-axis direction relative to the base 15. The second wafer transfer mechanism 25 includes a robot hand 252 supported on a base 251, and the base 251 is supported so as to be movable along a pair of guide rails 253 extending in the X-axis direction. The base 251 has a threaded portion (not shown) that screws into a ball screw 254 extending in the X-axis direction. When the ball screw 254 is rotated by the driving force of the motor, the base 251 moves in the X-axis direction.

[0040] The second wafer transfer mechanism 25 transfers wafers W between the temporary storage table 13 and the sheet cutting table 14 and the wafer holding unit 20 by moving the base 251 in the X-axis direction and operating the robot hand 252. More specifically, the second wafer transfer mechanism 25 can receive and transfer wafers W from the temporary storage table 13 before the protective member 32 is formed, and hand them over to the holding table 201 of the wafer holding unit 20. Furthermore, the second wafer transfer mechanism 25 can retrieve wafers W from the holding table 201 of the wafer holding unit 20 after the protective member 32 has been formed, and transfer them to the sheet cutting table 14.

[0041] The protective member forming apparatus 1 is centrally controlled by a control unit 40 (Figure 1), which consists of a processor that performs various processes and a memory that stores various parameters and programs.

[0042] The memory unit of the control unit 40 stores predetermined set values ​​for the process of forming the holding member. These predetermined set values ​​include, for example, the thickness of the wafer W, the amount of liquid resin 31 supplied, the processing speed of the holding unit 20, and the load value at which an error is triggered.

[0043] The memory unit of the management unit 40 stores programs that perform various processes. For example, it stores programs that perform various processes based on the load values ​​detected by the load detection unit 22. In addition, the memory unit of the management unit 40 stores programs for issuing errors, which will be described later, as part of the control program of the protective member forming apparatus 1.

[0044] The control unit 40 includes an alarm unit 42 as one of its functional blocks. The alarm unit 42 determines whether or not an error factor exists based on the change in the load value of the load detection unit 22, and if an error factor exists, it issues an error alarm. The factors that trigger an error alarm include, but are not limited to, the thickness of the wafer W not matching a preset thickness, the amount of liquid resin 31 supplied onto the sheet not matching a preset amount, the descent speed of the holding unit 20 being lowered being different from a preset speed, or a malfunction of the load detection unit.

[0045] The protective member forming apparatus 1 is equipped with an alarm device 44. When an error is triggered by the alarm unit 42, the operator is notified of the error through the alarm device. The alarm device 44 consists of a speaker, monitor screen, indicator lights, etc., installed on the external housing 10, and provides notification through sound from the speaker, error display on the monitor screen, and changes in the display pattern of the indicator lights (changes in lighting pattern, changes in color, etc.).

[0046] The control unit 43 is included as one of the functional blocks of the management unit 40. When the alarm unit 42 issues an error, if the resin supply unit 18 is supplying liquid resin onto the sheet, the control unit 43 brings the wafer W held by the holding unit into contact with the liquid resin and hardens the liquid resin. It also transports the wafer W after the liquid resin has hardened to the recovery unit C3.

[0047] It should be noted that the functions of the alarm generation unit 42 and the control unit 43 are realized by the operation of the processor, memory, and other components that make up the management unit 40, and this does not mean that the alarm generation unit 42 and the control unit 43 are composed of independent electronic components. Also, although Figure 1 schematically shows only the connection relationship between the alarm generation unit 42 and the control unit 43 and the load detection unit 22, the management unit 40 is also connected to each part of the protective member forming apparatus 1 other than the load detection unit 22 so that signals can be sent and received.

[0048] The formation of a protective member using the protective member forming apparatus 1 configured as described above will now be explained.

[0049] Figure 3 shows the sheet loading process. In the sheet loading process, the sheet transport unit 17 clamps the end of the sheet 30 with the clamp unit 173 and moves the arm 172 in the X-axis direction to pull the sheet 30 out from the sheet supply unit 171 and transport it to the sheet placement table 16. The pulled-out sheet 30 is cut to a predetermined length. The sheet 30 is placed on the sheet support surface 161 of the sheet placement table 16, and the suction source 162 operates to apply suction force to the suction holes (not shown) of the sheet support surface 161, thereby holding the sheet 30 in place. As a result, the sheet 30 adheres tightly to the sheet support surface 161. At this stage, the area of ​​the sheet 30 on the sheet support surface 161 is larger than the area of ​​the lower surface Wb of the wafer W.

[0050] Figure 4 shows the liquid resin supply process. In the liquid resin supply process, the resin supply nozzle 183 of the resin supply unit 18 is positioned above the sheet 30 which has been placed on the sheet support surface 161 by the previous sheet loading process. Then, the dispenser 181 is controlled to send liquid resin 31 to the resin supply nozzle 183, causing the liquid resin 31 to drip from the resin supply nozzle 183 onto the sheet 30. The resin supply nozzle 183 is positioned above the center of the sheet placement table 16, and the liquid resin 31 dripped from the resin supply nozzle 183 accumulates near the center of the upper surface of the sheet 30 in an area smaller than the area of ​​the wafer W.

[0051] Based on information such as the size of the wafer W, the control unit 40 instructs the resin supply unit 18 to supply a predetermined amount of liquid resin 31 to the sheet 30, in an amount sufficient to cover the entire underside Wb of the wafer W. Once the predetermined amount of liquid resin 31 has been supplied, the resin supply nozzle 183 is rotated to detach it from above the sheet mounting table 16, completing the liquid resin supply process.

[0052] Figure 5 shows the state in which the wafer W is held in the wafer holding section 20 by the wafer holding process. In the wafer holding process, the wafer W, before the protective member 32 is formed, is removed from the cassette C1 in the storage space 111 by the first wafer transport mechanism 12 and transported to the temporary storage table 13. On the temporary storage table 13, the orientation and center of the wafer W are detected by the wafer detection section 131. Once the orientation and center of the wafer W are detected, the wafer W is transported to the wafer holding section 20 by the second wafer transport mechanism 25. In the wafer holding section 20, the suction source 205 is operated to apply suction force to the porous member 202, and the upper surface Wa of the wafer W is sucked onto the wafer holding surface 203 and held in place.

[0053] Furthermore, at least a portion of the wafer holding process may be performed in parallel with (simultaneously with) the sheet loading process and the liquid resin supply process.

[0054] When the wafer W held in the wafer holder 20 is positioned opposite the liquid resin 31 on the sheet 30 (Figure 5), the process proceeds to the spreading step shown in Figure 6. In the spreading step, the motor 214 is operated by the lifting mechanism 21 to lower the lifting table 212 and the wafer holder 20 at a predetermined feed speed.

[0055] As the wafer holding unit 20 descends, the lower surface Wb of the wafer W approaches the sheet mounting table 16 and comes into contact with the liquid resin 31. The liquid resin 31 is then pressed by the lower surface Wb of the wafer W, causing it to spread radially across the wafer W. Before contact with the lower surface Wb of the wafer W, the liquid resin 31 is concentrated near the center of the sheet 30 (see Figure 5), and as it is pressed from the wafer W, the liquid resin 31 spreads toward the outer edge of the wafer W (see Figure 6).

[0056] As an alternative, the sheet mounting table 16 may be configured to be able to move up and down, so that when pressing the wafer W against the liquid resin 31, the sheet mounting table 16 can be raised to bring it closer to the wafer holding section 20.

[0057] As the wafer holder 20 is lowered and the liquid resin 31 is spread by the lower surface Wb of the wafer W, the load in the Z-axis direction (vertical direction) applied to the lower surface Wb of the wafer W (value of the pressing force from the wafer W to the liquid resin 31) increases. When the liquid resin 31 spreads to the entire lower surface Wb of the wafer W and extends outward from the outer edge of the wafer W, the above load begins to decrease. Such changes in load are detected using the load sensor 221 in the load detection unit 22.

[0058] The detection results from the load detection unit 22 (output signals from each load sensor 221) are input to the control unit 40. The control unit 40 refers to the detection results from the load detection unit 22 and controls the drive of the motor 214 of the lifting mechanism 21 according to the change in load in the Z-axis direction (vertical direction), thereby spreading the liquid resin 31 over the entire lower surface Wb of the wafer W (until it reaches the outer edge of the wafer W).

[0059] Whether or not the liquid resin 31 has spread over the entire lower surface Wb of the wafer W can be determined based on the detection result of the load detection unit 22. Figure 8 is a graph showing the relationship between the change in the height (position in the Z-axis direction) of the wafer holding unit 20 and the load value in the Z-axis direction detected by the load detection unit 22. In Figure 8, the change in the height of the wafer holding unit 20 is shown by the dashed line P, and the change in the load value detected by the load detection unit 22 is shown by the solid line Q. In the graph of Figure 8, the horizontal axis shows the passage of time, the vertical axis for the dashed line P shows the height of the wafer holding unit 20, and the vertical axis for the solid line Q shows the load value.

[0060] Section Pa shows the downward movement of the wafer holder 20 from the start of the spreading process until the lower surface Wb of the wafer W comes into contact with the liquid resin 31 and spreads. When the spreading start point Ta is reached, in which the wafer W begins to press against the liquid resin 31, the wafer holder 20 stops descending (section Pb), and the reaction force from the liquid resin 31 being spread acts on the lower surface Wb of the wafer W, causing the load value to increase (section Qa).

[0061] When the spread liquid resin 31 has spread to the entire lower surface Wb of the wafer W, and the liquid resin 31 extends outward from the outer edge of the wafer W, the load value changes from rising to falling (section Qb). A predetermined value Qc is set and stored in advance as a reference load value corresponding to the completion of the spreading of the liquid resin 31. The predetermined value Qc is set to a value lower than the peak of the load value (the value at the boundary between section Pa and section Pb), and when it is detected that the load value has reached the predetermined value Qc in section Pb, the control unit 40 determines that the liquid resin 31 has covered the entire lower surface Wb of the wafer W.

[0062] When the control unit 40 detects that the downward-turning load value has reached a predetermined value Qc, at the spreading completion determination point Tb, it reverses the operation of the motor 214 of the lifting mechanism 21 to slightly raise the wafer holding section 20 (section Pc). Once the wafer holding section 20 has been raised by a predetermined amount, the operation of the motor 214 is stopped to maintain a constant height for the wafer holding section 20 (section Pd).

[0063] Furthermore, when determining the state of the liquid resin 31's spread, the image captured by the imaging unit 24 may be referred to in conjunction with the detection by the load detection unit 22.

[0064] Once the spreading process is complete and the entire lower surface Wb of the wafer W is covered with liquid resin 31, the curing process shown in Figure 7 is performed. The point at which the wafer holding part 20 has been raised by a predetermined amount is defined as the curing start point Tc. In the curing process, ultraviolet UV light of sufficient intensity to cure the liquid resin 31 is irradiated from the ultraviolet irradiation part 231 of the curing mechanism 23 toward the sheet support surface 161. The ultraviolet UV light emitted from the ultraviolet irradiation part 231 passes through the translucent sheet mounting table 16 and sheet 30 to reach the liquid resin 31, curing the liquid resin 31, which is an ultraviolet curing resin. When the liquid resin 31 is judged to be sufficiently cured, the irradiation of ultraviolet UV light from the curing mechanism 23 is terminated.

[0065] In this embodiment, the curing mechanism 23 is described as curing the liquid resin 31 by irradiating it with ultraviolet UV light, but it is not limited to this configuration. The liquid resin 31 may be a thermosetting resin that cures in a predetermined temperature range, and the liquid resin 31 may be cured by applying external stimulation by heating.

[0066] When the liquid resin 31 hardens, the hardened resin (the original liquid resin 31) and the sheet 30 form a protective member 32 that covers the lower surface Wb of the wafer W. When it is determined that the liquid resin 31 has hardened and the formation of the protective member 32 is complete, the irradiation of ultraviolet UV from the ultraviolet irradiation unit 231 of the hardening mechanism 23 is terminated. At the same time, the operation of the suction source 162 is stopped, and the suction holding of the sheet 30 to the sheet support surface 161 of the sheet mounting table 16 is released.

[0067] Next, the motor 214 is operated by the lifting mechanism 21 to raise the lifting table 212 and the wafer holding unit 20, and the wafer W, which has the protective member 32 formed on it, is transferred from the wafer holding unit 20 to the robot hand 252 of the second wafer transfer mechanism 25. During this transfer, the communication between the wafer holding surface 203 of the wafer holding unit 20 and the suction source 205 is cut off, releasing the suction holding of the wafer W by the wafer holding unit 20. Specifically, by closing the on / off valve (not shown) provided in the suction passage 204 or stopping the operation of the suction source 205, the suction force is removed from acting on the wafer holding surface 203. Once the suction holding on the wafer holding unit 20 side is released, it becomes possible to transfer the wafer W to the robot hand 252 positioned below the wafer holding unit 20.

[0068] The second wafer transfer mechanism 25 transfers the wafer W received from the wafer holding unit 20 to the sheet cutting table 14. Using the sheet cutter 141, the excess sheet 30 is cut along the outer shape of the wafer W placed on the sheet cutting table 14.

[0069] Next, the first wafer transport mechanism 12 transports the wafer W from the sheet cutting table 14 to the cassette storage section 11, and places it in the cassette C2 within the storage space 112.

[0070] As described above, the formation of the protective member 32 on the wafer W in the protective member forming apparatus 1 is completed. The wafer W on which the protective member 32 has been formed is then transported to a processing apparatus separate from the protective member forming apparatus 1 for further processing.

[0071] For example, the wafer W is transported to a grinding machine, and the side opposite to the protective member 32 (the top surface Wa) is ground. During grinding in the grinding machine, the protective member 32 is pressed against the holding table of the grinding machine. The protective member 32, which has a predetermined thickness and is hardened, can withstand the pressure and allow the wafer W to be ground stably.

[0072] The above describes the case where the protective member 32 is properly formed, but we will now explain how to handle errors when the protective member 32 cannot be properly formed. The occurrence of such errors can be determined by the control unit 40 based on the detection results of the load detection unit 22.

[0073] The method for issuing an error based on the load value detected by the load detection unit 22 will be explained with reference to Figure 8. As a reference load value, the control unit 40 has a range from a predetermined upper limit Ra to a predetermined lower limit Rb that is pre-set and stored.

[0074] If the load detection unit 22 determines that an error factor exists based on the load value Q it has detected, the alarm unit 42 will issue an error alarm. Error factors include, for example, when it is detected that the thickness of the wafer W does not match a preset thickness, when it is detected that the amount of liquid resin 31 supplied onto the sheet 30 does not match a preset amount, when the descent speed of the wafer holding unit 20 is different from a preset speed, or when the load detection unit 22 malfunctions.

[0075] If any of these error factors occur, for example, if the load value Q does not rise to a predetermined lower limit Rb, or if it exceeds a predetermined upper limit Ra, it is determined that some kind of abnormal situation has occurred, and an error is issued. The error is issued by causing the alarm device 44 to perform a predetermined notification operation (sound, display) based on the alarm signal from the alarm unit 42.

[0076] For example, if the thickness of the wafer W is greater than the preset thickness, pressing the liquid resin 31 more strongly than with a wafer W of the appropriate thickness may cause the load value Q to increase when the load value Q in section Pb rises, potentially exceeding the predetermined upper limit Ra. If the thickness of the wafer W is less than the preset thickness, the force pressing the liquid resin 31 is weaker than with a wafer W of the appropriate thickness, causing the load value Q to decrease when the load value Q in section Pb rises, potentially falling below the predetermined lower limit Rb.

[0077] Therefore, if the load value Q does not fall within the range from a predetermined upper limit Ra to a predetermined lower limit Rb, the alarm unit 42 may determine that the thickness of the wafer W held by the wafer holding unit 20 is thinner or thicker than a preset thickness range, and based on this result, issue an error alarm. With this configuration, the thickness of the wafer W on which the protective member 32 is formed can be recognized, and it can be determined whether or not the wafer W has a predetermined thickness.

[0078] Furthermore, if the amount of liquid resin 31 supplied onto the sheet 30 does not match a preset amount, this will also be reflected as an abnormality in the load value Q detected by the load detection unit 22. For example, if the amount of liquid resin 31 supplied is insufficient compared to a preset amount, the pressing force on the liquid resin 31 from the wafer W will be weak, causing the load value Q to decrease as the load value Q rises in section Pb, potentially falling below a predetermined lower limit Rb. If the amount of liquid resin 31 supplied is too much compared to a preset amount, the excess liquid resin 31 will smoothly overflow from the outer edge of the wafer W, allowing the load value Q to remain between a predetermined upper limit Ra and a predetermined lower limit Rb. However, if the excess liquid resin 31 does not smoothly overflow from the outer edge of the wafer W but remains between the wafer W and the sheet 30, the load value Q may exceed a predetermined upper limit Ra as the load value Q rises in section Pb.

[0079] Therefore, if the load value Q does not fall within the range from a predetermined upper limit Ra to a predetermined lower limit Rb, the alarm unit 42 may determine that the amount of liquid resin 31 supplied onto the sheet 30 is less or more than a preset amount, and based on this result, it may issue an error alarm. With this configuration, it is possible to recognize the amount of liquid resin 31 forming the protective member 32 and to determine whether the amount of liquid resin 31 is appropriate.

[0080] Furthermore, if the descent speed of the wafer holding unit 20 differs from a preset speed, this will also be reflected as an abnormality in the load value Q detected by the load detection unit 22. For example, if the descent is too fast, the load value Q may exceed a predetermined upper limit value Ra.

[0081] Therefore, if the load value Q exceeds a predetermined upper limit value Ra, the alarm unit 42 may determine that the descent speed of the wafer holder 20 is faster than a preset speed and issue an error based on that result. With this configuration, the descent speed of the wafer holder 20 can be recognized, and it is possible to determine whether the descent speed of the wafer holder 20 is appropriate or not.

[0082] Furthermore, if the load detection unit 22 malfunctions, the change in load value Q shown in Figure 8 will not be properly detected. For example, if the thickness of the wafer W, the supply amount of liquid resin 31, and the lowering speed of the wafer holding unit 20 are all appropriate, but the load value Q does not reach a predetermined lower limit Rb, or if the load value Q exceeds a predetermined upper limit Ra, the alarm unit 42 may determine that the load detection unit 22 is malfunctioning and issue an error based on that result.

[0083] In this embodiment, a range from a predetermined upper limit Ra to a predetermined lower limit Rb is set for the load value Q. When the liquid resin 31 is spread, if the load value Q detected by the load detection unit 22 changes appropriately within that range, it can be determined that a wafer with the desired protective member can be formed. Conversely, if the load value Q detected by the load detection unit 22 does not change appropriately within that range when the liquid resin 31 is spread, it can be determined that the desired protective member cannot be formed due to various error factors. Furthermore, the alarm unit 42 issues an error and notifies the operator through the alarm device 44, making it possible to inform the operator whether or not it is possible to form a wafer with the desired protective member.

[0084] Upon receiving notification of an error, the worker checks each of the aforementioned error causes and takes action to resolve the error. This allows for prompt recognition and countermeasures against conditions that result in defects in the formation of the protective member 32, thereby improving the production efficiency of wafers W with protective members 32 of a predetermined thickness.

[0085] In this embodiment, the formation defect of the protective member 32 when the thickness of the wafer W is inappropriate is determined based on the detection content of the load detection unit 22. Therefore, the thickness of the wafer W can be recognized with a simple configuration without using a dedicated device for measuring the thickness of the wafer W.

[0086] Furthermore, since multiple error factors other than the thickness of the wafer W (excess or insufficient supply of liquid resin 31, excessive or insufficient descent speed of the wafer holding unit 20, and failure of the load detection unit 22) are also judged based on the detection content of the load detection unit 22, the configuration and control related to the formation of the protective member 32 can be simplified compared to when individual error factors are detected and judged independently.

[0087] Previously, when an error occurred and it was necessary to quickly remove the sheet 30, liquid resin 31, and wafer W from the sheet placement table 16, the operator would perform the removal directly. However, when the cover of the device (the external housing 10 of the protective member forming device 1) is opened, there is a risk that dust may enter the device and adhere to the upper surface of the sheet placement table 16, or that uncured liquid resin 31 may splatter during the removal process and adhere to the sheet placement table 16. This would then lead to problems during subsequent protective member formation, such as the inability to form the protective member 32 to a uniform thickness, or the adhesion of dust and other foreign matter to the protective member 32.

[0088] In this embodiment, when an error is reported, if the resin supply unit 18 is supplying liquid resin 31 onto the sheet 30, the control unit 43 brings the wafer W held by the wafer holding unit 20 into contact with the liquid resin 31 and cures the liquid resin 31. More specifically, after bringing the liquid resin 31 into contact with the lower surface Wb of the wafer W, the curing mechanism 23 is operated to irradiate ultraviolet UV light from the ultraviolet irradiation unit 231. As a result, regardless of whether the thickness or area of ​​the liquid resin 31 is excessive or insufficient, a cured resin is formed on the lower surface Wb of the wafer W.

[0089] Once the liquid resin 31 hardens, the wafer W in which the error occurred is transported to the recovery section C3 by the first wafer transport mechanism 12 and the second wafer transport mechanism 25. The method of transport at this time is the same as the method used to transport wafers W in which the protective member 32 has been properly formed.

[0090] Furthermore, although this embodiment uses two transport mechanisms, a first wafer transport mechanism and a second wafer transport mechanism, a configuration in which a single transport mechanism transports the wafers to the retrieval section C3 is also possible.

[0091] Thus, in this embodiment, when an error is triggered, after the liquid resin 31 has hardened, the wafer W in which the error occurred is transported to the recovery section C3 by the first wafer transport mechanism 12 and the second wafer transport mechanism 25.

[0092] This configuration prevents dust from entering the device (especially around the sheet placement table 16) and prevents uncured liquid resin 31 from adhering to the sheet placement table 16 during the removal process. This allows for the recovery of the sheet 30 placed on the sheet support surface 161, the liquid resin 31 dripped onto the sheet 30, and the wafer W that caused the error, without contaminating the inside of the device.

[0093] Furthermore, when the alarm unit 42 issues an error alarm, the control unit 43 may cure the liquid resin 31 that has been dropped onto the sheet 30 without allowing the wafer to come into contact with it, and instead of transporting it to the recovery unit C3, a person may remove it from the sheet placement table 16.

[0094] 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]

[0095] As described above, the protective member forming apparatus of the present invention has the effect of enabling the formation of wafers on which a desired protective member is formed, and is particularly useful in the manufacturing field of semiconductors and the like, which includes a step of forming a protective member on one side of a wafer. [Explanation of Symbols]

[0096] 1: Protective member forming apparatus 10: External enclosure 11: Cassette storage compartment 12: First wafer transport mechanism 13: Temporary Table 14: Sheet cutting table 15: Base 16: Sheet placement table 17: Sheet transport section 18: Resin supply unit 20: Wafer holding section 21: Lifting mechanism 22: Load detection unit 23:Curing mechanism 25: Second wafer transport mechanism 30: Sheet 31: Liquid resin 32: Protective component 40: Management Department 42: Reporting Department 43: Control Unit 44: Alarm device 183: Resin supply nozzle 201: Holding Table 203: Wafer holding surface 221: Load sensor 231: UV irradiation area C1: Cassette C2: Cassette C3: Recovery Department P: Change in the height of the wafer holder Q: Changes in load values ​​detected by the load detection unit Ra: Predetermined upper limit Rb: predetermined lower limit Ta: Starting point for spreading Tb: Point of judgment for completion of expansion Tc: Hardening start point UV: Ultraviolet light W: wafer Wa: Top surface Wb: Bottom surface (one side)

Claims

[Claim 1] A table on which to place the sheet, The table includes a sheet transport unit that transports sheets, A resin supply unit that supplies liquid resin onto the sheet placed on the table, A holding section that holds the wafer above the table, A lifting mechanism that moves the table and the holding part up and down relative to each other, A load detection unit that detects the load caused by bringing the table and the holding unit closer together to a predetermined distance and pressing the wafer held by the holding unit against the liquid resin on the sheet, A curing mechanism for curing liquid resin spread on the underside of a wafer, A transport mechanism for transporting the resin obtained by curing the liquid resin and the wafer with the sheet attached to its lower surface, A recovery unit for recovering the wafer with the resin and the sheet attached to its lower surface, An alarm unit that issues an error when the thickness of the wafer does not match a preset thickness, when the amount of liquid resin supplied onto the sheet does not match a preset amount, when the descent speed of the holding unit is different from a preset speed, or when the load detection unit malfunctions, and the load value detected by the load detection unit when the liquid resin supplied onto the sheet is pressed by the wafer held by the holding unit does not fall within the range of a predetermined upper limit to a predetermined lower limit. The system includes a control unit that hardens the liquid resin between the sheet and the lower surface of the wafer held by the holding unit when the alarm unit issues an error, A protective member forming apparatus that transports a wafer to a recovery section using a transport mechanism, the wafer to which the resin obtained by curing the liquid resin and the sheet are attached.

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