JP2018160577A - Processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To process a workpiece without causing clogging of a cutting blade and without using a laser processing apparatus when a plate-like workpiece formed into a film is divided.SOLUTION: A processing method includes a groove forming step of forming a groove M1 from the front surface W1a of a workpiece W along a dividing line S, a holding step of holding the front surface W1a side of the workpiece W to expose a film W2 on the back surface W2b side of the workpiece W after the groove forming step, a high pressure water injection step of injecting high pressure water J on the back surface W2b side of the workpiece W to divide the film W2 along the groove M1 and penetrating at least a part of the groove M1 on the back surface W2b side after the holding step, and a solid carbon dioxide particle injection step of injecting solid carbon dioxide particles P1 toward the back surface W2b side of the workpiece W to which the high pressure water is injected to remove the film W2 corresponding to the groove M1.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a processing method for a workpiece in which a film is formed on the back surface of a plate-like object and a plurality of division lines are set.

  When a plate-like object having a ductile film such as a metal film or a resin film is cut with a cutting blade, the cutting blade is clogged with the film. Therefore, a method of removing the film with a laser beam in advance before cutting is proposed (for example, see Patent Document 1).

JP2016-42526A

  However, when the film is removed with a laser beam, debris is generated, and processing is generally performed using an expensive laser processing apparatus, resulting in an increase in manufacturing cost.

  Therefore, when processing a film-shaped plate-shaped workpiece, the workpiece can be processed without causing clogging of the cutting blade and without using a laser processing apparatus. There are challenges.

  The present invention for solving the above problems is a processing method of a workpiece in which a film is formed on the back surface of a plate-like object and a plurality of scheduled cutting lines are set, and the cutting is performed from the surface of the workpiece. A groove forming step for forming a groove along a predetermined line, a holding step for holding the surface side of the workpiece and exposing the film on the back surface side of the workpiece after performing the groove forming step; After performing the holding step, a high-pressure water injection step of injecting high-pressure water onto the back surface side of the workpiece to divide the film along the groove and penetrating at least a part of the groove to the back surface side; And a solid carbon dioxide particle injecting step in which solid carbon dioxide particles are ejected onto the back side of the workpiece on which the high-pressure water has been ejected to remove the film corresponding to the grooves.

  A processing method according to the present invention includes a groove forming step for forming a groove in a film along a line to be cut from a surface of a workpiece, and after performing the groove forming step, the surface side of the workpiece is held and the workpiece is held. After carrying out the holding step for exposing the film on the back side of the workpiece and the holding step, high pressure water is sprayed on the back side of the workpiece to divide the film along the groove, and at least some of the grooves are on the back side. A high pressure water injection step for penetrating to the side, and a solid carbon dioxide particle injection step for removing the film corresponding to the grooves by injecting solid carbon dioxide particles on the back side of the workpiece on which the high pressure water has been injected. Therefore, without using a laser processing device, and without clogging the film with the cutting blade, the film is cut with high-pressure water, and the part corresponding to the groove of the film (chips become burr-like The portion that protrudes from the solid dioxide Was removed particles, it can be produced chips from the workpiece.

It is sectional drawing which shows an example of a to-be-processed object. It is sectional drawing which shows the state which has formed the groove | channel in the workpiece using the cutting device. It is sectional drawing which expands and shows an example of the groove | channel formed in the to-be-processed object. It is sectional drawing which shows an example of the plasma etching apparatus for forming a groove | channel in a to-be-processed object. It is sectional drawing which shows a part of workpiece in the state by which the protective tape was stuck on the surface side. It is sectional drawing which shows an example of the injection device which can inject high pressure water and a solid carbon dioxide particle to a workpiece. FIG. 3 is a cross-sectional view showing a state in which high pressure water is sprayed from a high pressure water spray nozzle along the groove to the back side of the workpiece, the film is divided along the groove, and the groove is penetrated to the back side of the workpiece. is there It is sectional drawing which shows the state which has ejected the solid carbon dioxide particle along the groove | channel on the back surface side of the workpiece into which the high pressure water was injected, and has removed the film | membrane corresponding to a groove | channel. It is sectional drawing which expands and shows a part of workpiece after a high-pressure water and solid carbon dioxide particles are injected. It is sectional drawing which shows the state which sprays a high pressure water from the rotating high pressure water injection nozzle to a film | membrane, divides | segments a film | membrane along a groove | channel, and has penetrated the groove | channel to the back surface side of the workpiece. It is sectional drawing which shows the state which has ejected the solid carbon dioxide particle to the back surface side of the workpiece in which the high-pressure water was ejected from the swirling solid carbon dioxide particle ejection nozzle, and removed the film corresponding to the groove.

  The workpiece W shown in FIG. 1 is a circular semiconductor wafer provided with a plate-like object W1 made of silicon, for example, and the surface of the plate-like object W1, that is, the surface W1a of the workpiece W is divided into a plurality of parts. The planned lines S are set so as to be orthogonal to each other. The devices D are respectively formed in the lattice-like regions partitioned by the division line S. In FIG. 1, a film W2 having a uniform thickness (for example, 0.5 μm to 10 μm) made of a metal such as copper and nickel is formed on the back surface W1b of the plate-like object W1 facing in the −Z direction. Is formed. The exposed surface of the film W2 becomes the back surface W2b of the workpiece W. A notch (not shown) for identifying the crystal orientation is formed on the outer peripheral edge of the workpiece W so as to be recessed radially inward toward the center of the workpiece W. Note that the configuration of the workpiece W is not limited to the example shown in the present embodiment. For example, the plate-like object W1 may be made of sapphire, gallium, silicon carbide, or the like in addition to silicon, and the film W2 is not a metal film, for example, DAF (Die Attach Film) or DBF (Die Backside Film). A resin film having a thickness of about 5 μm to 30 μm may be used.

(Embodiment 1)
Hereinafter, each step of the processing method in the case where the processing method according to the present invention is performed to produce a chip including the device D from the workpiece W shown in FIG. 1 will be described.

(1-1) Groove Forming Step Using Cutting Device First, a groove forming step is performed in which a groove is formed from the surface W1a of the workpiece W shown in FIG. In this groove forming step, for example, grooves are formed using the cutting device 1 shown in FIG.

  In forming the groove, as shown in FIG. 2, the workpiece W has a dicing tape T1 larger in diameter than the workpiece W adhered to the back surface W2b, and the outer peripheral portion of the adhesive surface of the dicing tape T1. Is attached to the annular frame F1. Then, the workpiece W with the surface W1a exposed upward is supported by the annular frame F1 via the dicing tape T1, so that it can be handled by the annular frame F1.

  The cutting device 1 shown in FIG. 2 includes, for example, a cutting unit that performs cutting with a chuck table 10 that sucks and holds a workpiece W and a cutting blade 110 that rotates with respect to the workpiece W held on the chuck table 10. 11 and at least.

  The chuck table 10 has, for example, a circular outer shape, and sucks and holds the workpiece W on a holding surface 10a made of a porous member or the like. The chuck table 10 can rotate around the axis in the vertical direction (Z-axis direction) and can reciprocate in the X-axis direction by a cutting feed means (not shown). For example, four (only two in the illustrated example) fixing clamps 100 are equally disposed on the outer periphery of the chuck table 10 in order to fix the annular frame F1.

  The cutting means 11 includes a spindle 111 whose axial direction is a direction (Y-axis direction) perpendicular to the horizontal direction with respect to the moving direction (X-axis direction) of the workpiece W, and an annular ring is formed at the tip of the spindle 111. The cutting blade 110 is fixed.

  First, as shown in FIG. 2, the workpiece W supported by the annular frame F1 is sucked and held by the chuck table 10 with the surface W1a facing upward. Further, the annular frame F <b> 1 is clamped and fixed by each fixing clamp 100. Next, the coordinate position in the Y-axis direction of the planned cutting line S where the cutting blade 110 is to be cut is detected by alignment means (not shown). As the planned cutting line S is detected, the cutting means 11 is indexed and fed in the Y-axis direction, and the cutting blade 110 is positioned with respect to the planned cutting line S to be cut.

  As the motor (not shown) rotationally drives the spindle 111, the cutting blade 110 rotates at a high speed in the clockwise direction as viewed from the −Y direction, for example. Further, the cutting means 11 is cut and fed toward the −Z direction, and the cutting means 11 is positioned at a height position where the lowermost end of the cutting blade 110 completely cuts the plate-like object W1 and does not cut into the film W2, for example. . The cutting means 11 is at a height position at which the cutting blade 110 does not completely cut the plate-like object W1, that is, at a height position where the lowermost end of the cutting blade 110 is slightly above the back surface W1b of the plate-like object W1. May be positioned.

  The chuck table 10 that holds the workpiece W is fed to the −X direction side (the back side of the paper surface) at a predetermined cutting feed speed, so that the rotating cutting blade 110 moves along the planned cutting line S. A groove M1 that does not reach the film W2 shown in FIGS. 2 and 3 is formed by cutting into the plate-like object W1 from the surface W1a side. As shown in FIG. 3, for example, the surface W2a of the film W2 is exposed at the groove bottom of the groove M1. The groove M1 may be formed so that the uncut portion of the plate-like object W1 remains with a slight thickness as the bottom of the groove M1.

  When the workpiece W is sent to a predetermined position in the X-axis direction at which the cutting blade 110 finishes cutting one cutting scheduled line S, the cutting feed of the workpiece W is once stopped and the cutting blade 110 is processed. The workpiece W moves away from the workpiece W, and then the workpiece W moves in the + X direction and returns to the origin position. Then, by sequentially performing the same cutting while indexing and feeding the cutting blade 110 in the + Y direction at intervals of the adjacent dividing lines S, the film W2 is not reached along all the dividing lines S in the X-axis direction. A groove M1 having a depth is formed in the workpiece W. Further, by performing the same cutting process after rotating the workpiece W by 90 degrees, the groove M1 having a depth that does not reach the film W2 shown in FIG. Can do.

(1-2) Groove Forming Step Using Plasma Etching Apparatus The groove forming step is performed using the plasma etching apparatus 9 shown in FIG. 4 instead of using the cutting apparatus 1 shown in FIG. May be.

  The plasma etching apparatus 9 shown in FIG. 4 includes an electrostatic chuck 90 that holds a workpiece W, a gas ejection head 91 that ejects gas, and a chamber 92 that houses the electrostatic chuck 90 and the gas ejection head 91 therein. It has.

  For example, an electrostatic chuck 90 formed of a ceramic such as alumina or a dielectric such as titanium oxide is supported from below by a support member 900. Inside the electrostatic chuck 90, an electrode (metal plate) 901 that generates an electric charge when a voltage is applied is disposed in parallel with the holding surface 90a of the electrostatic chuck 90, and the electrode 901 is aligned. The device 94a is connected to a bias high-frequency power source 95a. For example, the electrostatic chuck 90 is not limited to a monopolar electrostatic chuck as in the present embodiment, and may be a so-called bipolar electrostatic chuck.

  A gas diffusion space 910 is provided inside a gas ejection head 91 that is disposed at the top of the chamber 92 so as to be movable up and down via a bearing 919. A gas introduction port 911 communicates with the upper portion of the gas diffusion space 910. A plurality of gas discharge ports 912 communicate with the lower part of the gas diffusion space 910. The lower end of each gas discharge port 912 is opened toward the holding surface 90 a of the electrostatic chuck 90.

A gas supply unit 93 is connected to the gas inlet 911. The gas supply unit 93 stores, for example, a fluorine-based gas such as SF ₆ , CF ₄ , C ₂ F ₆ , C ₂ F ₄ as an etching gas.

  A high-frequency power source 95 is connected to the gas ejection head 91 via a matching device 94. By supplying high-frequency power from the high-frequency power source 95 to the gas ejection head 91 via the matching unit 94, the etching gas discharged from the gas discharge port 912 can be turned into plasma. The plasma etching apparatus 9 includes a control unit (not shown), and conditions such as gas discharge amount, time, and high-frequency power are controlled under the control of the control unit.

An exhaust port 96 is formed at the bottom of the chamber 92, and an exhaust device 97 is connected to the exhaust port 96. By operating the exhaust device 97, the inside of the chamber 92 can be depressurized to a predetermined degree of vacuum.
On the side of the chamber 92, a loading / unloading port 920 for loading and unloading the workpiece W and a gate valve 921 for opening and closing the loading / unloading port 920 are provided.

When the workpiece W is subjected to plasma etching to form a groove, each device D (not shown in FIG. 4) is protected by the resist film R. That is, for example, after a positive resist solution is applied to the surface W1a of the workpiece W and a resist film having a uniform thickness is formed on the surface W1a, only the planned dividing line S is irradiated with ultraviolet light and exposed. By developing the subsequent workpiece W, the line S scheduled to be exposed is exposed and the device D is protected by the resist film R.
Further, a tape or a hard plate is attached as a protective member T2 to the back surface W2b of the workpiece W, and the back surface W2b is protected by the protective member T2.

  In forming the groove, first, the gate valve 921 is opened, the workpiece W is loaded into the chamber 92 from the loading / unloading port 920, and the workpiece W is held on the holding surface of the electrostatic chuck 90 with the surface W1a facing upward. Place on 90a. The gate valve 921 is closed, the inside of the chamber 92 is exhausted by the exhaust device 97, and the inside of the chamber 92 is made a sealed space with a predetermined pressure.

The gas ejection head 91 is lowered to a predetermined height position, and in this state, an etching gas mainly composed of, for example, SF ₆ is supplied from the gas supply unit 93 to the gas diffusion space 910 and ejected downward from the gas discharge port 912. Further, a high frequency power is applied from the high frequency power source 95 to the gas ejection head 91 to generate a high frequency electric field between the gas ejection head 91 and the electrostatic chuck 90, thereby converting the etching gas into plasma. In parallel with this, a voltage is applied to the electrode 901 from the bias high-frequency power supply 95a, thereby generating a dielectric polarization phenomenon between the holding surface 90a of the electrostatic chuck 90 and the workpiece W, and static electricity due to charge polarization. The workpiece W is sucked and held on the holding surface 90a by the electroadsorption force.

  The plasma-ized etching gas does not etch each device D covered with the resist film R, but performs anisotropic etching on the planned dividing line S in the -Z direction. Therefore, the lattice-shaped groove | channel M1 along the division | segmentation scheduled line S shown in FIG. 3 is formed in the plate-shaped object W1.

The plasma etching gas does not etch the metal film W2. Therefore, as shown in FIG. 3, after performing plasma etching until the bottom of the groove M1 does not reach the inside of the film W2 and the surface W2a of the film W2 is exposed at the bottom of the groove M1, the plasma etching is terminated. . That is, the introduction of the etching gas or the like into the chamber 92 shown in FIG. 4 and the supply of the high frequency power to the gas ejection head 91 are stopped, and the etching gas in the chamber 92 is exhausted from the exhaust port 96 to the exhaust device 97. The etching gas is not present in the chamber 92.
Note that plasma etching may be performed until the plate-like object W1 remains in the bottom of the groove M1 shown in FIG.
Note that the groove forming step is not limited to the above-described form performed by the plasma etching using the SF6 gas alone, and the plasma etching using the SF6 gas and the protective film deposition (deposition) on the groove side wall or the like by the C4F8 are repeated alternately. It may be performed by the Bosch method.

  Next, the resist film R is removed from the surface W1a of the workpiece W shown in FIG. The removal of the resist film R is performed by, for example, wet processing using a predetermined chemical or ashing (ashing) of the resist film R by the plasma etching apparatus 9.

(2) Holding step After performing either (1-1) the groove forming step using the cutting apparatus 1 or (1-2) the groove forming step using the plasma etching apparatus 9 as described above, the workpiece W A holding step of holding the front surface W1a side and exposing the film W2 on the back surface W2b side of the workpiece W is performed.

  In the holding step, first, as shown in FIG. 5, the protective tape T3 is attached to the front surface W1a of the workpiece W, and the dicing tape T1 shown in FIG. The protective member T2 shown in FIG. As shown in FIG. 6, for example, the protective tape T3 formed to have a larger diameter than the outer diameter of the workpiece W is in a state of being attached to the ring frame F2, and the back surface W2b is exposed upward. The workpiece W in the finished state can be handled by the ring frame F2.

As shown in FIG. 6, the workpiece W supported by the ring frame F <b> 2 is conveyed to the injection device 3 via the protective tape T <b> 3. The injection device 3 includes, for example, a holding table 30 that sucks and holds the workpiece W, high-pressure water injection means 31 that injects high-pressure water onto the workpiece W and divides the film W2 along the groove M1, and a workpiece At least solid carbon dioxide particle ejecting means 32 for ejecting solid carbon dioxide particles onto the object W to remove the film W2 corresponding to the groove M1 and control means (not shown) are provided.
The control means including a storage element such as a CPU and a memory is electrically connected to the holding table 30, the high-pressure water injection means 31, and the solid carbon dioxide particle injection means 32, and under the control of the control means, the high-pressure water The movement operation of the injection means 31 and the solid carbon dioxide particle injection means 32 and the rotation operation of the holding table 30 are controlled.

  The holding table 30 has, for example, a circular outer shape, and sucks and holds the workpiece W on a holding surface 30a communicating with a suction source (not shown). The holding table 30 can be rotated around the axis in the vertical direction (Z-axis direction) and can be reciprocated in the X-axis direction by a processing feed means (not shown). For example, four fixing clamps 300 (only two are illustrated in the illustrated example) are equally disposed on the outer peripheral portion of the holding table 30 in order to fix the ring frame F2.

  The workpiece W supported by the ring frame F2 is placed on the holding surface 30a of the holding table 30 with the protective tape T3 side down, so that the film W2 on the back surface W2b side of the workpiece W is formed. It will be in the state exposed upwards. The suction force generated by a suction source (not shown) is transmitted to the holding surface 30a, whereby the surface W1a side of the workpiece W is sucked and held by the holding table 30. Further, the ring frame F <b> 2 is fixed by each fixing clamp 300.

(3) High-pressure water injection step Next, high-pressure water is injected from the high-pressure water injection means 31 shown in FIG. 6 to the back surface W2b side of the workpiece W to divide the film W2 along the groove M1, and at least some of the grooves M1 is penetrated to the back surface W2b side. The high-pressure water injection means 31 includes a high-pressure water injection nozzle 310. The high-pressure water injection nozzle 310 is disposed above the holding table 30 and can move in the Y-axis direction and the Z-axis direction. Further, the high-pressure water injection nozzle 310 has an injection port 310a facing the holding surface 30a of the holding table 30. For example, the diameter of the injection port 310a is variable to a desired size by a slide member (not shown). . The high-pressure water injection nozzle 310 communicates with a high-pressure water supply source 311 that supplies high-pressure water to the high-pressure water injection nozzle 310 via a pipe 311a.

  In injecting high-pressure water along the groove M1 from the back surface W2b side of the workpiece W, first, one groove M1 that first injects high-pressure water is detected. The detection of the groove M1 is executed by, for example, the groove detection means 39 shown in FIG.

For example, the groove detection means 39 includes a diameter of the workpiece W, a distance between a notch formed on the outer peripheral edge of the workpiece W and each scheduled cutting line S formed on the surface W1a of the plate-like object W1, and a plurality of A pattern design value of the workpiece W indicating information such as an interval between the scheduled division lines S is stored.
The groove detection means 39 includes a notch detection unit 390 that is disposed above the holding table 30 and detects a notch (not shown) of the workpiece W, for example. The notch detection unit 390 is configured by, for example, a light reflection type optical sensor, and the outer periphery of the workpiece W moves the detection area of the notch detection unit 390 as the holding table 30 that holds the workpiece W rotates. By passing, the notch formed in the outer periphery of the workpiece W can be detected. Note that the notch detector 390 may be configured by a camera or the like, and the notch of the workpiece W may be detected by the notch detector 390 performing image processing on a captured image formed by the camera.

  When the notch of the workpiece W is detected by the notch detection unit 390, the groove M1 is formed along the planned cutting line S. Therefore, the groove detection means 39 stores the detected notch and the workpiece stored in advance. From the pattern design value of the object W, it is possible to detect the relative position of the single groove M1 for injecting the high-pressure water with respect to the notch position serving as the reference position. Next, the groove detection means 39 sends a detection signal about the position of one groove M1 with respect to the position of the notch to a control means (not shown). Upon receiving this detection signal, the control means rotates the holding table 30 by a predetermined angle to position the notch of the workpiece W at a predetermined coordinate position, so that one groove M1 for injecting high-pressure water has a desired coordinate position. Adjust so that it is positioned at. Specifically, for example, the workpiece W is placed so that a virtual line passing through the center of the workpiece W and the notch is parallel to the X-axis direction and the notch is positioned on the −X direction side. The holding table 30 to be held is rotated. Then, for example, as shown in FIG. 7, one groove M1 for first injecting high-pressure water is in a state extending in parallel to the X-axis direction, and the Y-axis coordinates of this one groove M1 The position is recognized.

In addition, the detection of the groove | channel M1 is not limited to the form made by the groove | channel detection means 39 shown in FIG. For example, it is assumed that the holding table 30 is made of a transparent member such as glass, and the ejection device 3 includes an alignment unit including a camera disposed below the holding table 30. In this case, light is irradiated from below the holding table 30 and transmitted through the holding table 30, and the reflected light of the surface W1a of the workpiece W is imaged on the image sensor of the camera, thereby forming the workpiece W. A captured image showing the surface W1a is formed. Then, the alignment means performs image processing such as pattern matching based on the captured image formed by the camera, so that the groove M1 formed along the planned division line S of the workpiece W can be detected.
For example, when the film W2 is wavy along the groove M1, the workpiece W may be imaged by the camera from the back surface W2b side of the workpiece W, and the groove M1 may be detected by the alignment means.

  Next, the holding table 30 that holds the workpiece W shown in FIG. 7 is sent out to the forward direction in the −X direction (the back side of the drawing in FIG. 7), and immediately below the injection port 310 a of the high-pressure water injection nozzle 310. The high-pressure water injection nozzle 310 moves in the Y-axis direction so that the center line of the groove M1 whose coordinate position is recognized is located. The workpiece W is further fed in the −X direction at a predetermined machining feed rate, and the high-pressure water supply source 311 supplies high-pressure water to the high-pressure water jet nozzle 310.

  As shown in FIG. 7, the high pressure water J jetted downward from the jet port 310a of the high pressure water jet nozzle 310 collides with the film W2 along the groove M1, so that the film W2 breaks along the groove M1. It is divided and becomes burr-like. Further, the groove M1 penetrates to the back surface W2b side of the workpiece W. The pressure of the high-pressure water J is, for example, a pressure (for example, 100 MPa to 300 MPa) at which the plate-like object W1 is not damaged or the chips C are not scattered, and the spot diameter of the high-pressure water J takes into account the width of the groove M1, etc. And adjusted to an appropriate value. Note that, by dividing the film W2 along the groove M1 by the high-pressure water J, one whole groove M1 extending in the X-axis direction may not penetrate through to the back surface W2b side, and at least a part of one groove M1. May penetrate to the back surface W2b side. That is, the film W2 may have a part where a dividing start point is formed along the groove M1, or a part which is stretched along the groove M1 and becomes thin and easily divided.

(4) Solid carbon dioxide particle injection step Solid carbon dioxide particles are injected from the solid carbon dioxide particle injection means 32 shown in FIGS. 6 and 8 onto the back surface W2b side of the workpiece W on which high-pressure water has been injected to form the groove M1. The film W2 corresponding to is removed.
The solid carbon dioxide particle injection means 32 includes an injection nozzle 320, and the injection nozzle 320 is disposed above the holding table 30 and is movable in the Y-axis direction and the Z-axis direction. The injection nozzle 320 has an injection port 320a facing the holding surface 30a of the holding table 30. For example, the diameter of the injection port 320a is variable to a desired size by a slide member (not shown). The injection nozzle 320 communicates with a carbon dioxide supply source 321 that supplies liquid carbon dioxide to the injection nozzle 320 via a pipe 321a. The injection nozzle 320 communicates with an air supply source 322 that supplies compressed air to the injection nozzle 320 via a pipe 322a.

  In the solid carbon dioxide particle injection step, as shown in FIG. 8, high-pressure water J is injected from a high-pressure water injection nozzle 310 (not shown in FIG. 8) immediately below the injection port 320 a of the injection nozzle 320. The injection nozzle 320 moves in the Y-axis direction so that the center line of the groove M1 is located. That is, the injection nozzle 320 is positioned behind the high-pressure water injection nozzle 310 that injects the high-pressure water J.

  Liquid carbon dioxide is supplied from the carbon dioxide supply source 321 to the injection nozzle 320, and air is supplied from the air supply source 322 to the injection nozzle 320. When liquid carbon dioxide and air are mixed at high pressure in the injection nozzle 320 and injected into the atmosphere as an injection from the injection port 320a, the temperature of the liquid carbon dioxide falls below the freezing point due to adiabatic expansion, resulting in an extremely fine powder. Dry ice (solid carbon dioxide particles) P1 is generated.

  The workpiece W is fed to the −X direction side (the back side of the drawing) at a predetermined machining feed rate, so that the jet nozzle 320 moves backward from the high-pressure water jet nozzle 310 that jets high-pressure water along the groove M1. Move relatively to the + X direction side (the front side of the page). When the solid carbon dioxide particles P1 ejected from the ejection nozzle 320 collide with the film W2 of the workpiece W after jetting the high-pressure water J, the solid carbon dioxide particles P1 are deformed and crushed into carbon dioxide gas. Sublimate. The expansion energy generated by sublimation of the solid carbon dioxide particles P1 is added to the burr-shaped portion of the film W2 after the high-pressure water J injection (the portion of the film W2 that protrudes from the chip C), so that the film W2 becomes It is blown off from the groove M1 and removed from the chip C. In addition, the portion where the separation starting point is formed along the groove M1 of the film W2 and the portion which is stretched along the groove M1 to be thin and easy to be separated are also caused by vaporization expansion of the solid carbon dioxide particles P1. It is divided and further blown off from the groove M1 and removed from the chip C. The supply amount of liquid carbon dioxide, the supply amount of air, and the spray spot diameter are adjusted to appropriate values in consideration of the width of the groove M1 and the like.

  For example, the high-pressure water injection nozzle 310 finishes injecting the high-pressure water J along the single groove M1 onto the film W2, and the injection nozzle 320 that follows the high-pressure water injection nozzle 310 from behind is along the single groove M1. When the workpiece W advances in the -X direction to a predetermined position in the X-axis direction where the solid carbon dioxide particles P1 are completely ejected onto the film W2, the machining feed of the workpiece W in the -X direction (forward direction) is performed. Stop once.

Next, the high pressure water injection nozzle 310 and the injection nozzle 320 are moved in the + Y direction, and the groove M1, the high pressure water injection nozzle 310, and the injection that are located next to the groove M1 into which the high pressure water J and the solid carbon dioxide particles P1 are injected. Position alignment with the nozzle 320 in the Y-axis direction is performed based on the pattern design value of the workpiece W. Then, a processing feed means (not shown) processes and feeds the workpiece W in the + X direction (return direction), and the high-pressure water J is sprayed onto the film W2 along the groove M1 in the same way as the forward direction. Further, solid carbon dioxide particles P1 are jetted in the same way as the forward direction so as to follow the same groove M1 on the back surface W2b side of the workpiece W to which the high-pressure water J has been jetted.
Similarly, the high pressure water J and solid carbon dioxide particles P1 are sprayed onto the film W2 along all the grooves M1 extending in the X-axis direction in the same manner, and after the film W2 is divided by the high pressure water J, the solid carbon dioxide particles P1 The film W2 corresponding to the groove M1 is removed. Further, when the high pressure water J and the solid carbon dioxide particles P1 are sprayed in the same manner after rotating the holding table 30 by 90 degrees, the membrane W2 is divided by the high pressure water J along all the vertical and horizontal grooves M1, The film W2 corresponding to the groove M1 is removed by the solid carbon dioxide particles P1. As a result, as shown in FIG. 9, the workpiece W can be divided into individual chips C each including the device D and the film W2.

  In the processing method according to the present invention, the groove forming step for forming the groove M1 along the planned division line S from the surface W1a of the workpiece W, and the surface W1a side of the workpiece W after the groove forming step are performed. After holding and exposing the film W2 on the back surface W2b side of the workpiece W, and carrying out the holding step, high pressure water J is sprayed on the back surface W2b side of the workpiece W and the film along the groove M1. A high-pressure water injection step for dividing W2 and penetrating at least a part of the groove M1 to the back surface W2b side, and injecting solid carbon dioxide particles P1 to the back surface W2b side of the workpiece W on which the high-pressure water J has been injected Since the solid carbon dioxide particle injection step for removing the film W2 corresponding to the groove M1 is provided, the laser processing apparatus is not used, and the cutting blade 110 is not clogged by the film W2, High pressure water For example, the film W2 is divided line by line along the groove M1, for example, and the burr-shaped portion of the film W2 is ejected by high-pressure water J, and the line is removed line by line along the groove M1 by the solid carbon dioxide particles P1. Thus, the chip C can be manufactured from the workpiece W.

(Embodiment 2)
Hereinafter, each step of the processing method in the case where the processing method according to the present invention is performed to produce a chip including the device D from the workpiece W shown in FIG. 1 will be described. In Embodiment 2 of the processing method according to the present invention, as in Embodiment 1 of the processing method according to the present invention, first, (1-1) a groove forming step using a cutting device, or (1-2) plasma etching. Any one of the groove forming steps using the apparatus is performed, and as shown in FIG. 3, a groove M1 having a depth that does not reach the film W2 along all the division lines S is formed in the workpiece W.

(2) Holding step (1-1) After performing either the groove forming step using the cutting apparatus 1 or (1-2) the groove forming step using the plasma etching apparatus 9, as shown in FIG. The protective tape T3 is attached to the surface W1a of the workpiece W, and the dicing tape T1 shown in FIG. 2 or the protective member T2 shown in FIG. 4 is peeled from the back surface W2b of the workpiece W.

  As shown in FIG. 10, the protective tape T3 formed to have a larger diameter than the outer diameter of the workpiece W is adhered to the ring frame F2, and the workpiece W can be handled by the ring frame F2. It becomes a state. And as shown in FIG. 10, the to-be-processed object W of the state supported by the ring frame F2 is conveyed to the injection apparatus 4 via the protective tape T3. The injection device 4 includes, for example, a holding table 40 that holds the workpiece W, a rotating unit 42 that rotates the holding table 40, and a bottomed cylindrical casing 44 that has a circular opening on the upper end side. Yes.

  For example, the holding table 40 has a circular outer shape and includes a holding surface 40a made of a porous member or the like and communicating with a suction source. Around the holding table 40, for example, four fixing clamps 401 for fixing the ring frame F <b> 2 (only two in the illustrated example are illustrated) are arranged equally. The holding table 40 can be moved up and down, and when the workpiece W is placed, the workpiece 40 is raised and positioned at the loading / unloading height position of the workpiece W, and the workpiece held by suction is held. When the injection is injected onto the object W, the injection W is positioned at the injection height position in the casing 44.

  The rotating means 42 disposed on the lower side of the holding table 40 includes a spindle 420 which is fixed at the upper end on the bottom surface side of the holding table 40 and can be rotated around a vertical axis, a motor and the like, and a lower end of the spindle 420. And at least a rotational drive source 421 coupled to the side. When the rotation drive source 421 rotates the spindle 420, the holding table 40 fixed to the spindle 420 also rotates.

  The holding table 40 is accommodated in the internal space of the casing 44. The casing 44 stands from an outer wall 440 that surrounds the holding table 40, a bottom plate 441 that is integrally connected to the lower portion of the outer wall 440 and has an opening through which the spindle 420 is inserted, and an inner peripheral edge of the opening of the bottom plate 441. It is comprised from the inner wall 442 to provide, and is supported by the leg part 443 by which the end was fixed to the baseplate 441. A circular cover between the lower surface of the holding table 40 and the upper end surface of the inner wall 442 of the casing 44 that is inserted into the spindle 420 and prevents foreign matter from entering the gap between the spindle 420 and the opening of the bottom plate 441. A member 444 is provided.

  In the casing 44, a high-pressure water injection nozzle 45 capable of injecting high-pressure water onto the film W2 of the workpiece W sucked and held by the holding surface 40a, and powdered dry ice (solid carbon dioxide) are applied to the film W2. A solid carbon dioxide particle injection nozzle 46 capable of injecting particles) with air pressure is disposed. Each of the high-pressure water injection nozzle 45 and the solid carbon dioxide particle injection nozzle 46 is erected from the bottom plate 441 of the casing 44, and has an outer shape that is substantially L-shaped in side view. The injection port 450 formed at the front end portion of the high-pressure water injection nozzle 45 and the injection port 460 formed at the front end portion of the solid carbon dioxide particle injection nozzle 46 open toward the holding surface 40a of the holding table 40, respectively. . The high-pressure water injection nozzle 45 and the solid carbon dioxide particle injection nozzle 46 are each turnable about the axis in the Z-axis direction, and the respective injection ports 450 and 460 are provided from above the holding table 40 to the retracted position. Can move.

The high-pressure water injection nozzle 45 communicates with a high-pressure water supply source 47 that supplies high-pressure water toward the high-pressure water injection nozzle 45 via a pipe 47a and a rotary joint (not shown).
The solid carbon dioxide particle injection nozzle 46 is connected to a carbon dioxide supply source 48 in which liquid carbon dioxide is stored via a pipe 48a, a rotary joint (not shown), and the like. The solid carbon dioxide particle injection nozzle 46 is connected to an air supply source 49 that stores compressed air (compressed air) via a pipe 49a and a rotary joint (not shown).

  The workpiece W supported by the ring frame F2 is placed on the holding surface 40a of the holding table 40 with the protective tape T3 side down, so that the film W2 on the back surface W2b side of the workpiece W is formed. It will be in the state exposed upwards. Then, the suction force generated by a suction source (not shown) is transmitted to the holding surface 40a, whereby the surface W1a side of the workpiece W is sucked and held by the holding table 40. Further, the ring frame F <b> 2 is fixed by each fixing clamp 401.

(3) High-pressure water injection step Next, high-pressure water is injected from the high-pressure water injection nozzle 45 to divide the film W2 along the groove M1, and penetrate at least a part of the groove M1 to the back surface W2b side. First, the holding table 40 holding the workpiece W is lowered to the working height position in the casing 44. Further, the high-pressure water injection nozzle 45 is pivoted and the injection port 450 is positioned above the center of the film W2 of the workpiece W.

  Next, the high pressure water supply source 47 supplies high pressure water to the high pressure water injection nozzle 45. Since the area | region corresponding to the groove | channel M1 of the film | membrane W2 is not supported by the plate-shaped object W1 from the downward direction, as shown in FIG. 10, the high pressure water J injected downward from the injection port 450 collides with the film | membrane W2. As a result, the film W2 is broken along the groove M1 and becomes burrs. Further, the groove M1 is in a state of penetrating to the back surface W2b side of the workpiece W. The pressure of the high-pressure water J is, for example, a pressure (for example, 100 MPa to 300 MPa) at which the plate-like object W1 is not damaged or the chips are not scattered.

  A high-pressure water injection nozzle 45 that injects high-pressure water swivels above the workpiece W so as to reciprocate around the axis in the Z-axis direction at a predetermined angle. Furthermore, when the rotation drive source 421 rotates the spindle 420 in the counterclockwise direction as viewed from the + Z direction side, for example, the holding table 40 rotates in the same direction, and the entire surface of the film W2 of the workpiece W is pressurized. High pressure water J is jetted from the water jet nozzle 45. Note that, by dividing the film W2 along the groove M1 by the high pressure water J, the entire groove M1 does not have to penetrate to the back surface W2b side, and at least a part of each groove M1 penetrates to the back surface W2b side. Just do it. That is, the film W2 may have a part where a dividing start point is formed along the groove M1, or a part which is stretched along the groove M1 and becomes thin and easily divided.

  After the high-pressure water J is sprayed onto the film W2 of the workpiece W for a predetermined time, the supply of high-pressure water to the high-pressure water spray nozzle 45 is stopped, and the high-pressure water spray nozzle 45 is swung to move above the workpiece W. Evacuate from.

(4) Solid Carbon Dioxide Particle Injection Step Next, as shown in FIG. 11, the solid carbon dioxide particle injection nozzle 46 pivots and the injection port 460 is positioned above the center of the film W <b> 2 of the workpiece W. The carbon dioxide supply source 48 supplies liquid carbon dioxide, and the air supply source 49 supplies air to the solid carbon dioxide particle injection nozzle 46. When liquid carbon dioxide and air are mixed at high pressure in the solid carbon dioxide particle injection nozzle 46 and injected into the atmosphere as an injection from the injection port 460, extremely fine powdery dry ice (solid carbon dioxide particles) ) P1 occurs.

  Furthermore, the solid carbon dioxide particle injection nozzle 46 that injects the solid carbon dioxide particles P1 is swung so as to reciprocate at a predetermined angle around the axis of the Z-axis direction above the rotating workpiece W. Solid carbon dioxide particles P1 are jetted from the solid carbon dioxide particle jet nozzle 46 over the entire surface of the film W2 of the workpiece W. When the solid carbon dioxide particles P1 collide with the film W2 of the workpiece W, they are sublimated to carbon dioxide gas. The energy generated as a result of the gas expansion is applied to the burr-shaped portion of the film W2 after jetting the high-pressure water J (the portion of the film W2 that protrudes from the chip C), so that the film W2 blows off from the groove M1. And removed from chip C. In addition, the portion where the separation starting point is formed along the groove M1 of the film W2 and the portion which is stretched along the groove M1 to be thin and easy to be separated are also caused by vaporization expansion of the solid carbon dioxide particles P1. It is divided and further blown off from the groove M1 and removed from the chip C. By injecting solid carbon dioxide particles P1 onto the film W2 of the workpiece W for a predetermined time, the workpiece W is divided into individual chips C each having the device D and the film W2, as shown in FIG. be able to.

  In Embodiment 2 of the processing method according to the present invention, the laser processing apparatus is not used, the clogging due to the film W2 is not generated in the cutting blade 110, and, for example, a predetermined area above the workpiece W is set. High-pressure water J is jetted from the high-pressure water jet nozzle 45 that reciprocates so as to reciprocate at an angle to divide the membrane W2 along the groove M1, and further swivels so as to reciprocate above the workpiece W at a predetermined angle. Chip C can be produced from workpiece W by ejecting solid carbon dioxide particles P1 from moving solid carbon dioxide particle ejection nozzle 46 to remove the burr-shaped portion of film W2. Further, depending on the processing conditions such as the thickness of the film W2, suitable times for the injection time of the high-pressure water J and the injection time of the solid carbon dioxide particles P1 are respectively determined, and the injection time of the high-pressure water J and the solid dioxide dioxide are determined. It is possible to set the length of the injection time of the carbon particles P1.

W: Work piece W1: Plate-like object W1a: Surface of the work piece S: Line to be cut D: Device W1b: Back face of the plate-like object W2: Film W2a: Surface of the film W2b: Back face of the work piece
T1: Dicing tape F1: Annular frame M1: Groove 1: Cutting device 10: Chuck table 10a: Holding surface 100: Fixed clamp 11: Cutting means 110: Cutting blade 111: Spindle 9: Plasma etching device 90: Electrostatic chuck 90a: Electrostatic chuck holding surface 900: support member 901: electrode 91: gas ejection head 910: gas diffusion space 911: gas inlet 912: gas outlet
92: Chamber 920: Loading / unloading port 921: Gate valve 93: Gas supply unit 94, 94a: Matching unit 95, 95a: High frequency power source, bias high frequency power source 96: Exhaust port 97: Exhaust device R: Resist film T2: Protection member 3: Injection device 30: Holding table 30a: Holding surface 300: Fixed clamp 31: High pressure water injection means 310: High pressure water injection nozzle 310a: Injection port 311: High pressure water supply source 311a: Piping
32: Solid carbon dioxide particle injection means 320: Injection nozzle 320a: Injection port 321: Carbon dioxide supply source 321a: Pipe 322: Air supply source 322a: Pipe 39: Groove detection means 390: Notch detection unit F2: Ring frame T3: Protection Tape 4: Injection device 40: Holding table 40a: Holding surface 401: Fixed clamp 42: Rotating means 420: Spindle 421: Rotation drive source 44: Casing 440: Outer wall 441: Bottom plate 442: Inner wall 443: Leg
444: Cover member 45: High pressure water injection nozzle 47: High pressure water supply source 47a: Pipe 46: Solid carbon dioxide particle injection nozzle 48: Carbon dioxide supply source 48a: Pipe 49: Air supply source 49a: Pipe

Claims (1)

A processing method of a workpiece in which a film is formed on the back surface of a plate-like object, and a plurality of scheduled cutting lines are set,
A groove forming step of forming a groove along the line to be cut from the surface of the workpiece;
After performing the groove forming step, holding the surface side of the workpiece and exposing the film on the back side of the workpiece; and
After carrying out the holding step, a high-pressure water injection step for injecting high-pressure water onto the back surface side of the workpiece to divide the film along the groove and penetrating at least a part of the groove to the back surface side. When,
A solid carbon dioxide particle injecting step of injecting solid carbon dioxide particles onto the back surface side of the workpiece on which high-pressure water has been injected to remove the film corresponding to the grooves.

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