Processing method of silicon wafer

Abstract

To provide a processing method of a silicon wafer, capable of removing a silicon dust adhered onto an adhesive film even in the case of cutting a wafer with the adhesive film.SOLUTION: A processing method of a silicon wafer 108 by a dust removing device, comprises: an adhesive film adhesion step of adhering an adhesive film 109 to a whole surface of a front surface 101 of the silicon wafer 108; a holding step of holding the silicon wafer 108 by a chuck table 20 by setting the adhesive film 109 to an upper side; a groove processing step of processing a processing groove to the adhesive film 109 and the silicon wafer 108 along a street 102 by using a groove processing mechanism of a cutting blade or a laser beam irradiation unit; and a dust removing step of removing a silicon dust by ejecting a gas which is subjected to plasma processing of SF6 or CF4 to the silicon dust adhered onto the front surface 101 of at least the adhesive film 109 after the groove processing step.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for processing a silicon wafer. [Background technology]

[0002] In the chip manufacturing process, as in Patent Documents 1 and 2, a non-conductive adhesive film (NCF (Non Conductive Film)) is attached to the surface of a wafer, and the wafer is cut along the streets formed on the wafer to manufacture chips. Examples of non-conductive adhesive films are disclosed in Patent Documents 3 and 4, for example. The chip is then laminated by adhering it to a support substrate. In addition to the above-mentioned NCF, other such adhesive films include ACF (Anisotropic Conducting Film).

[0003] In addition, as a processing mechanism for creating a processed groove in a chip groove processing step, there are cutting with a cutting blade and laser processing by irradiating a laser beam. Problems with laser processing have been improved as in the technology disclosed in Patent Document 5. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-032829 [Patent Document 2] JP 2020-194886 A [Patent Document 3] JP 2005-229040 A [Patent Document 4] International Publication No. 2016 / 052444 [Patent Document 5] JP 2023-020446 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional technology, it is necessary to form a protective film by applying a liquid resin, which has problems of consumables and time required for forming the protective film. In addition, when the protective film is not formed, silicon chips caused by the laser processing adhere to the adhesive film. In addition, the cutting process of the silicon wafer made of silicon has a problem of silicon chips adhering to the kerf and the surface of the adhesive film.

[0006] Therefore, the method of cutting the silicon wafer by using a cutting blade or a laser beam to cut the silicon wafer together with the adhesive film has a problem to be solved, which is to prevent silicon debris from adhering to the adhesive film.

[0007] The present invention has been made in consideration of the above points, and has an object to provide a method for processing a silicon wafer that makes it possible to remove silicon debris adhering to an adhesive film even when the silicon wafer is cut together with the adhesive film. [Means for solving the problem]

[0008] The silicon wafer processing method of the present invention is a silicon wafer processing method in which a silicon wafer having a plurality of chips with electrodes on its surface, with streets formed between the chips, is processed along the streets, and includes the following steps: an adhesive film applying step of applying an adhesive film to the entire surface of the silicon wafer for electrically connecting the electrodes to wiring of a supporting substrate and bonding them; a holding step of holding the silicon wafer on a chuck table with the adhesive film facing up; a groove processing step of processing grooves in the adhesive film and the silicon wafer along the streets using a cutting blade or a laser beam groove processing mechanism; and a debris removing step of spraying SF6 or CF4 plasma gas onto silicon debris adhering to at least the surface of the adhesive film after the groove processing step to remove the silicon debris.

[0009] One aspect of the present invention includes a fluoride layer removal step, which is performed after the debris removal step, in which a plasma gas containing oxygen atoms is sprayed onto the fluoride layer that has been fluorinated on the surface of the adhesive film during the debris removal step in a vacuum chamber, thereby removing the fluoride layer by plasma ashing.

[0010] In one embodiment of the present invention, the adhesive film is an anisotropic conductive film.

[0011] In one embodiment of the present invention, the adhesive film is a non-conductive film.

[0012] The adhesive film in one embodiment of the present invention has a two-layer structure of an anisotropic conductive film and a non-conductive film. Effect of the Invention

[0013] According to the present invention, even when the silicon wafer is cut together with the adhesive film, it is possible to remove silicon debris adhering to the adhesive film. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view showing a work set including a silicon wafer that is a processing target of a silicon wafer processing method according to an embodiment. FIG. [Diagram 2] 1 is a cross-sectional view showing a groove machining apparatus for performing a silicon wafer machining method according to an embodiment. [Diagram 3] 1 is a diagram showing a debris removal device for performing a silicon wafer processing method according to an embodiment; [Figure 4] 2 is a flowchart showing a process of a silicon wafer processing method according to an embodiment. [Diagram 5] FIG. 11 is a cross-sectional view showing a groove machining apparatus for executing a silicon wafer machining method according to a modified embodiment. [Figure 6] FIG. 11 is a cross-sectional view showing a debris removal device for performing a silicon wafer processing method according to a modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a processing system for performing the silicon wafer processing method according to the present embodiment will be described with reference to the attached drawings. The processing system includes an adhesive film attachment device, a groove processing device, a chip removal device, an expander device, and a replacement device. FIG. 1 is a perspective view showing a work set including a silicon wafer that is a processing target of the silicon wafer processing method according to the embodiment. FIG. 2 is a cross-sectional view showing a groove processing device that executes the silicon wafer processing method according to the embodiment. FIG. 3 is a diagram showing a chip removal processing device that executes the silicon wafer processing method according to the embodiment. FIG. 4 is a flow chart showing the processing of the silicon wafer processing method according to the embodiment. The silicon wafer processing method includes at least an adhesive film attachment step, a holding step, a groove processing step, and a chip removal step, which will be described later.

[0016] A method for processing a workpiece according to an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a work set 200 includes a silicon wafer 108, an adhesive film 109, a dicing tape 105, and a ring frame 106.

[0017] As shown in FIG. 1, a silicon wafer 108 has chips 103 formed in areas defined by a plurality of streets 102 formed in a lattice pattern on a surface 101 thereof.

[0018] Silicon wafer 108 has adhesive film 109 attached to front surface 101 (upper surface) and dicing tape 105 attached to back surface 104 (lower surface).

[0019] The adhesive film 109 is formed of an anisotropic conductive film. In the above embodiment, the adhesive film 109 is formed of an anisotropic conductive film, but is not limited to this, and may be formed of a non-conductive film. The adhesive film 109 may be formed of a two-layer structure of an anisotropic conductive film and a non-conductive film. The adhesive film 109 is formed, for example, using a resin that softens by heat, and has a function of fixing the chip 103 obtained by dividing the silicon wafer 108 to any object (for example, another chip or a substrate). The adhesive film 109 is heated to soften it, and the chip 103 is pressed against the substrate and cooled to be bonded. This adhesive film 109 is bonded to the entire surface 101 of the silicon wafer 108 in order to conduct the electrodes to the wiring of the support substrate.

[0020] The dicing tape 105 is a resin film that stretches when a force is applied, and has, for example, a disk-like shape with a diameter larger than that of the adhesive film 109. Furthermore, the outer peripheral portion of the dicing tape 105 is attached to an annular ring frame 106 whose inner diameter is larger than that of the silicon wafer 108 and the adhesive film 109. The adhesive film 109 is divided into chips 103 along the streets 102 together with the silicon wafer 108. The dicing tape 105 is an adhesive tape having an adhesive layer. The dicing tape 105 may be a resin sheet without an adhesive layer.

[0021] The ring frame 106 is attached to the outer edge of the dicing tape 105. As a result, the silicon wafer 108 constitutes a work set 200 supported by the dicing tape 105 in the opening 107 of the ring frame 106. The silicon wafer 108 is supported by the ring frame 106 via the dicing tape 105 and is carried into an expanding device (not shown). The work set 200 including the silicon wafer 108 is set in the expanding device, and the dicing tape 105 is expanded to increase the distance between adjacent chips 103. The wafer may be divided and the adhesive film 109 may be broken.

[0022] 2, the groove machining device 2 is a device that forms a processed groove 401 in a silicon wafer 108. The groove machining device 2 includes a laser processing unit 120 as shown in FIG.

[0023] The laser processing unit 120 includes a chuck table 121, a holding surface 122, a clamp unit 123, and a laser beam irradiation unit 124. The chuck table 121 holds the back surface 104 side of the silicon wafer 108 via the dicing tape 105 with the holding surface 122. The clamp unit 123 clamps the ring frame 106 attached to the silicon wafer 108.

[0024] The laser processing unit 120 performs alignment to align the silicon wafer 108 on the chuck table 121 with the irradiation position of the laser beam 400 by the laser beam irradiation unit 124. After that, the laser beam irradiation unit 124 performs laser processing by irradiating the laser beam 400 along the street 102 from the surface 101 side of the silicon wafer 108, thereby removing the adhesive film 109 on the street 102 and forming a processed groove 401 along the street 102. When forming the processed groove 401 by irradiating the laser beam 400 along the street 102, silicon contained in the silicon wafer 108 may fly off as silicon chips such as cutting chips and debris and adhere to the surface 111 of the adhesive film 109. Therefore, in this embodiment, the silicon chips adhered to the surface 111 of the adhesive film 109 are removed by the chip removal device 1.

[0025] 3, the debris removal apparatus 1 is an apparatus for removing silicon debris and fluoride layers adhering to a surface 111 of an adhesive film 109 attached to a silicon wafer 108. As shown in FIG. 3, the debris removal apparatus 1 includes a vacuum chamber 10, a chuck table 20, a suction source 30, a gas supply source 40, a plasma generating unit 50, and a control unit 80.

[0026] 3, the vacuum chamber 10 is provided with an internal space 11, a loading / unloading port 12, a door 13, a door operating unit 14, an installation stand 15, an exhaust path 17, an air supply path 18, and a pressure gauge 19. The housing of the vacuum chamber 10 is grounded.

[0027] The internal space 11 is a space formed inside the vacuum chamber 10 and separated from the atmosphere. The load / unload port 12 is a through-hole formed on the side of the vacuum chamber 10 that communicates between the atmosphere and the internal space 11, and serves as a path for loading and unloading the silicon wafer 108 into and from the internal space 11.

[0028] The door 13 is for loading and unloading, and is installed near the loading / unloading opening 12 so as to be movable between a closed position at which the door covers the loading / unloading opening 12 and cuts off communication between the atmosphere and the internal space 11 via the loading / unloading opening 12, and an open position at which the door is retracted from the closed position and allows communication between the atmosphere and the internal space 11 via the loading / unloading opening 12. The door operating unit 14 moves the door 13 between the closed position and the open position.

[0029] The installation table 15 is installed in a central region in the width direction below the internal space 11. The exhaust path 17 is installed on the side of the installation table 15 below the internal space 11, and communicates between the internal space 11 and the suction sources 301, 302 via valves 171 that can be switched between an open position and a closed position. In the embodiment, the exhaust path 17 exhausts the inert gas supplied from the inert gas supply source 42, the oxygen gas supplied from the oxygen gas supply source 43, or the processing gas supplied from the processing gas supply source 41.

[0030] The air supply passage 18 is installed in a central region in the width direction above the internal space 11 so as to face the installation table 15, and communicates between the internal space 11 and the gas supply source 40. The air supply passage 18 includes a dispersion member 181 installed so as to cover the opening on the internal space 11 side. In the embodiment, the dispersion member 181 is formed, for example, in a cylindrical shape with a plurality of through holes, and distributes the gas in a plasma state supplied from the gas supply source 40 side to the holding surface 21 of the chuck table 20 in the internal space 11.

[0031] The pressure gauge 19 is provided in the housing of the vacuum chamber 10 facing the internal space 11, and is a measuring system that measures the air pressure in the internal space 11. The debris removal device 1 can appropriately adjust the opening and closing of the valves 171, 411, 421, and 431 based on the air pressure in the internal space 11 measured by the pressure gauge 19.

[0032] The chuck table 20 is accommodated in the vacuum chamber 10. Specifically, the chuck table 20 is installed on an installation stand 15 installed in the internal space 11. As shown in Fig. 3, the chuck table 20 includes a holding surface 21, a suction path 22, an electrode 24, a DC power source 25, a cooling fluid path 27, and a cooling fluid source 28. The main body of the chuck table 20 is formed of an insulating material having electrical insulation properties.

[0033] The holding surface 21 is a flat surface formed above the chuck table 20, and holds the back surface 104 of the silicon wafer 108 via the dicing tape 105. The suction path 22 is formed inside the chuck table 20, and communicates between the holding surface 21 and the suction source 301 via a valve 221 that can be switched between an open position and a closed position.

[0034] When the valve 221 of the chuck table 20 is switched to an open state, a negative pressure is applied from the suction source 301 to the holding surface 21. When the air pressure in the internal space 11 of the chuck table 20 is 50 Pa or more, a sufficient pressure difference is generated between the negative pressure acting on the holding surface 21 and the air pressure in the internal space 11, so that the holding surface 21 can suction-hold (vacuum-hold) the silicon wafer 108 with sufficient strength due to the negative pressure acting on the holding surface 21. On the other hand, when the air pressure in the internal space 11 of the chuck table 20 is less than 50 Pa, a pressure difference between the negative pressure acting on the holding surface 21 and the air pressure in the internal space 11 becomes small, so that the holding surface 21 can only suction-hold (vacuum-hold) the silicon wafer 108 with a weak force due to the negative pressure acting on the holding surface 21.

[0035] A plurality of electrodes 24 are embedded inside the chuck table 20 and are electrically connected to a DC power supply 25. The DC power supply 25 can apply different DC voltages to the electrodes 24. When a DC voltage is applied by the DC power supply 25 to the electrodes 24 and a potential difference is generated between the electrodes 24, the electrodes 24 generate a predetermined electric field so as to cover the holding surface 21 of the chuck table 20. By generating this predetermined electric field, the electrode 24 enables the holding surface 21 of the chuck table 20 to electrostatically attract the silicon wafer 108 and enables the processing gas and / or oxygen gas in the form of plasma to be suitably drawn into the silicon wafer 108 held on the holding surface 21 of the chuck table 20.

[0036] Furthermore, when the application of DC voltage from DC power supply 25 is stopped and the potential difference generated between the electrodes 24 is eliminated, electrode 24 eliminates the predetermined electric field that has been generated to cover holding surface 21 of chuck table 20. By eliminating this predetermined electric field, electrode 24 eliminates the state in which silicon wafer 108 has been electrostatically attracted to holding surface 21 of chuck table 20.

[0037] The cooling fluid path 27 is formed inside the chuck table 20, and is connected to a cooling fluid source (cooling water source) 28. The cooling fluid source 28 supplies a cooling fluid to the cooling fluid path 27. When the cooling fluid supplied by the cooling fluid source 28 flows inside the cooling fluid path 27, the cooling fluid path 27 cools the holding surface 21 of the chuck table 20. By cooling the holding surface 21 of the chuck table 20, the cooling fluid path 27 can cool the silicon wafer 108 held by the holding surface 21 of the chuck table 20.

[0038] In the embodiment, the suction source 30 includes a suction source 301 connected to the suction path 22 and a suction source 302 connected to the exhaust path 17. In the embodiment, the suction source 30 includes two suction sources 301 and 302, but the present invention is not limited to this form and may include one suction source or three separate sources.

[0039] In this embodiment, a vacuum pump that draws a vacuum from the internal space 11 is preferably used as the suction source 30. Here, the vacuum refers to a so-called reduced pressure state, and for example, refers to a state in which the air pressure in the internal space 11 of the vacuum chamber 10 is lower than atmospheric pressure. 5 Pa~10 2 Low vacuum of about 10 Pa or 2 Pa~10 -1 The vacuum pump preferably used for the suction source 30 is capable of evacuating the internal space 11 to an atmospheric pressure at which low pressure plasma can be realized while introducing oxygen gas and an inert gas, and for example, a dry pump or oil rotary pump that realizes a low vacuum is used in combination with a turbo molecular pump or oil diffusion pump that realizes a medium vacuum. Here, being able to realize low pressure plasma means that it is possible to turn a processing gas or an inert gas into plasma in a vacuum (reduced pressure state).

[0040] 3, the gas supply source 40 includes a processing gas supply source 41, an inert gas supply source 42, and an oxygen gas supply source 43. The processing gas supply source 41 is connected to the air supply passage 18 via a valve 411 that can be switched between an open position and a closed position. The inert gas supply source 42 is connected to the air supply passage 18 via a valve 421 that can be switched between an open position and a closed position. In addition, the oxygen gas supply source 43 is connected to the air supply passage 18 via a valve 431 that can be switched between an open position and a closed position.

[0041] The processing gas supply source 41 supplies sulfur hexafluoride (SF6) gas as a processing gas. The debris removal device 1 injects a gas (hereinafter also referred to as "plasma gas 501") obtained by converting the supplied SF6 gas into plasma, onto the silicon debris adhering to the surface 111 of the adhesive film 109 laminated on the surface 101 side of the silicon wafer 108. By injecting the plasma gas 501 onto the silicon debris, the silicon debris adhering to the surface 111 of the adhesive film 109 can be removed.

[0042] In the embodiment, the processing gas supply source 41 supplies sulfur hexafluoride gas as the processing gas, but the present invention is not limited thereto, and any compound or mixture gas containing fluorine atoms may be supplied as the processing gas as long as it is a compound or mixture gas that can be turned into plasma and sprayed to remove and process silicon scraps attached to at least the surface 111 of the adhesive film 109 laminated on the surface 101 side of the silicon wafer 108. For example, the processing gas supply source 41 may supply carbon tetrafluoride (tetrafluoromethane, CF4) gas instead of sulfur hexafluoride as the processing gas. The ability to remove silicon scraps attached to the surface of the adhesive film of the silicon wafer 108 refers to the ability to remove silicon scraps at a predetermined speed or higher by remote plasma sprayed with the plasma gas 501.

[0043] The remote plasma refers to spraying the plasma gas 501, which is generated by supplying a processing gas such as SF6 gas or CF4 gas into the plasma generated between a pair of plasma electrodes 51, onto the silicon wafer 108. A voltage of several to several tens of kilovolts is applied between the pair of plasma electrodes 51. In the existing plasma etching, etching is performed in the depth direction of the silicon wafer 108, whereas in the remote plasma, etching is spread in the width direction of the silicon wafer 108, which is different. Therefore, by removing silicon debris using the remote plasma, it is possible to remove silicon debris attached to the entire surface 101 of the silicon wafer 108. This makes it possible to make the entire surface 101 of the silicon wafer 108 uniform.

[0044] Then, by spraying the plasma gas 501 onto the silicon wafer 108, fluorine generated by converting the SF6 gas or CF4 gas into plasma reacts with silicon contained in the silicon scraps attached to the adhesive film 109 attached to the silicon wafer 108. The generated fluorine reacts with silicon contained in the silicon scraps according to the following reaction formula (1), to produce silicon fluoride (Sin F 2n+2 ) is generated, and silicon debris adhering to the adhesive film 109 can be removed.

[0045] Si + 2F2 → Si n F 2n+2 ...Equation (1)

[0046] As silicon fluoride, for example, silicon tetrafluoride (SiF4) is generated. The process of removing the silicon layer attached to the adhesive film 109 by remote plasma is hereinafter also referred to as a "debris removing process".

[0047] The inert gas supply source 42 supplies helium (He) gas as an inert gas. Even if the supplied He gas is turned into plasma and sprayed onto at least the silicon scraps adhering to the surface 101 of the adhesive film 109, the silicon scraps cannot be removed.

[0048] In the embodiment, the inert gas supply source 42 supplies helium (He) gas as an inert gas, but the present invention is not limited to this, and any compound or mixture of gases may be supplied as an inert gas as long as the compound or mixture of gases is inactive to the silicon wafer 108 even when plasmatized. In this case, being inactive to the silicon wafer 108 means that the silicon wafer 108 is etched only at a rate lower than a predetermined rate, and any chemical reaction caused to the silicon wafer 108 proceeds only at a rate lower than a predetermined reaction rate. The inert gas supply source 42 may also supply, for example, nitrogen (N2) gas, argon (Ar) gas, or clean dry air (CDA: Clean Dry Air) as an inert gas. In addition, in the processing method for the silicon wafer 108 according to the present embodiment, only the inert gas supply source 42 is used, but the present invention is not limited to this, and the inert gas supply source 42 may be used alone or in combination with another inert gas supply source not shown.

[0049] In this embodiment, the valve 421 is provided to supply the inert gas supplied from the inert gas supply source 42 to the internal space 11 of the vacuum chamber 10 .

[0050] The oxygen gas supply source 43 supplies oxygen (O2) gas. The oxygen gas is turned into plasma, and the plasma is sprayed onto the fluoride layer on the surface 101 of the adhesive film 109, thereby removing the fluoride layer by plasma ashing.

[0051] In the embodiment, the oxygen gas supply source 43 supplies oxygen (O2) gas, but is not limited thereto, and oxygen plasma obtained by plasmatizing a compound or mixture containing oxygen atoms capable of removing the fluoride layer attached to the surface of the adhesive film 109 of the silicon wafer 108 may be sprayed onto the fluoride layer. For example, ozone (O3) or air (air containing moisture (H2O)) may be plasmatized as the oxygen gas.

[0052] Plasma ashing is a process in which oxygen plasma, which is formed by converting oxygen atoms generated between a pair of plasma electrodes 51, is sprayed onto a workpiece, causing a reaction between the surface of the workpiece and the oxygen.

[0053] In this embodiment, oxygen plasma is sprayed onto the surface of the adhesive film 109 to be processed, and oxygen reacts with fluorine in the fluoride layer formed on the surface of the adhesive film 109. By reacting according to the following reaction formula (2), oxygen fluoride such as oxygen difluoride (OF2) is generated, and the fluoride layer attached to the adhesive film 109 can be removed.

[0054] O2+ 2F2→ 2OF2...Equation (2)

[0055] The step of removing the fluoride layer attached to the adhesive film 109 by plasma ashing is hereinafter also referred to as the "fluoride layer removing step."

[0056] In addition, in the method for processing the silicon wafer 108 according to this embodiment, only one oxygen gas supply source 43 is used, but the present invention is not limited to this, and only one oxygen gas supply source 43 may be used, or it may be used in combination with another oxygen gas supply source (not shown).

[0057] In this embodiment, the valve 431 is provided to supply oxygen gas from the oxygen gas supply source 43 to the internal space 11 of the vacuum chamber 10 .

[0058] The plasma generating unit 50 is a mechanism for converting the processing gas and oxygen gas supplied from the gas supply source 40 through the air supply path 18 toward the holding surface 21 of the chuck table 20 in the internal space 11 into plasma inside the air supply path 18, and includes a pair of plasma generating electrodes 51 and a high-frequency power source 52. In the embodiment, the plasma generating unit 50 makes it possible to supply gases such as plasma gas 501 and oxygen gas that have been converted into a plasma state in the air supply path 18 outside the vacuum chamber 10 to the internal space 11 of the vacuum chamber 10.

[0059] The pair of plasma generating electrodes 51 are disposed opposite each other across the air supply passage 18. The high frequency power supply 52 can apply high frequency power between the pair of plasma generating electrodes 51. When high frequency power is applied from the high frequency power supply 52, the pair of plasma generating electrodes 51 can convert the gas passing through the air supply passage 18 into plasma by radicalizing or ionizing the gas.

[0060] In this embodiment, the remote plasma etching conditions are as follows: the frequency of the radio frequency power applied between the pair of plasma electrodes 51 by the radio frequency power supply 52 is set to 2.45 GHz, and the pressure in the internal space 11 of the vacuum chamber 10 from which the plasma gas of SF6 or CF4 is injected is set to a negative pressure value of 100 to 400 Pa. Furthermore, the plasma ashing conditions are as follows: the frequency of the radio frequency power applied between the pair of plasma electrodes 51 by the radio frequency power supply 52 is set to 13.56 MHz, and the pressure in the internal space 11 of the vacuum chamber 10 from which the oxygen gas such as O2 is injected is set to a negative pressure value of 10 to 50 Pa.

[0061] In addition, the plasma ashing is not limited to remote plasma as in the above embodiment. As shown in FIG. 6, the debris removal device 1 of the modified example has substantially the same configuration as the above embodiment except for the upper electrode 61, the lower electrode 62, the support arm 73, the lifting mechanism 91, and the high frequency power source 92, so that the description will be omitted. The upper electrode 61 is attached with a support arm 73 connected to the lifting mechanism 91. The upper electrode 61 can be moved up and down by the lifting mechanism 91 and the support arm 73. The lower electrode 62 is disposed below the upper electrode 61 so as to face the upper electrode 61 in the internal space 11 of the vacuum chamber 10. The upper electrode 61 and the lower electrode 62 are formed of a conductive material. The upper electrode 61 and the lower electrode 62 are connected to a high frequency power source 92 outside the vacuum chamber 10. 6, a silicon wafer 108 is carried into the internal space 11 of the vacuum chamber 10, and the silicon wafer 108 is held on the holding surface 21 of the chuck table 20. After that, the internal space 11 of the vacuum chamber 10 is set to a negative pressure value of 10 to 50 Pa. Then, a method may be used in which oxygen is supplied from the oxygen gas supply source 43 of the gas supply source 40 through the air supply passage 18 to the internal space 11, while high frequency power having a frequency of 13.56 MHz is supplied from the high frequency power source 92 to the upper electrode 61 in the internal space 11 and the lower electrode 62 of the chuck table, to turn the oxygen supplied to the internal space 11 into plasma.

[0062] The loading / unloading unit (not shown) moves along the opening direction of the loading / unloading port 12, using the loading / unloading port 12 as a movement path, between a loading / unloading position above the holding surface 21 of the chuck table 20 in the internal space 11 of the vacuum chamber 10 and a retracted position outside the vacuum chamber 10 after retracting from the loading / unloading position. The loading / unloading unit has a gripping portion (not shown) that grips the silicon wafer 108 facing downward, i.e., on the surface facing the holding surface 21 of the chuck table 20 at the loading / unloading position. In the embodiment, the loading / unloading unit is provided at two locations, but the present invention is not limited to this, and may be provided at one location or three or more locations as long as it is capable of gripping the silicon wafer 108. In the embodiment, a robot hand is exemplified as a suitable loading / unloading unit.

[0063] The control unit 80 controls each component of the debris removal apparatus 1 and causes the debris removal apparatus 1 to perform each operation on the silicon wafer 108. In the embodiment, the control unit 80 includes a computer system. The control unit 80 has an arithmetic processing device having a microprocessor such as a CPU (central processing unit), a storage device having a memory such as a ROM (read only memory) or a RAM (random access memory), and an input / output interface device. The arithmetic processing device performs arithmetic processing according to a computer program stored in the storage device, and outputs control signals for controlling the debris removal apparatus 1 to each component of the debris removal apparatus 1 via the input / output interface device.

[0064] As shown in FIG. 4, the processing method of the silicon wafer 108 according to the embodiment is generally performed using the scrap removal device 1 and the groove processing device 2, and includes a work set forming step ST11, an adhesive film attaching step ST12, a holding step ST13, a groove processing step ST14, a division step ST15, a scrap removal step ST16, and a fluoride layer removing step ST17. The processing method of the silicon wafer 108 according to the embodiment is a method of spraying a plasma gas 501 obtained by making SF6 into a plasma on the silicon scraps attached to at least the surface 111 of the adhesive film 109 after the groove processing step ST14, thereby removing the silicon scraps. In the above-mentioned embodiment, the plasma gas 501 obtained by making SF6 into a plasma is sprayed on at least the silicon scraps attached to the surface 111 of the adhesive film 109, but this is not limited thereto, and the plasma gas 501 obtained by making CF4 into a plasma may be sprayed on at least the silicon scraps attached to the surface 111 of the adhesive film 109. The division step ST15 may be performed in the groove processing step ST14. The dividing step ST15 may be performed after the debris removing step ST16 or the fluoride layer removing step ST17.

[0065] In the work set forming step ST11, as shown in FIG. 1, a silicon wafer 108 is attached to a ring frame 106 via a dicing tape 105 to form a work set 200. In the work set forming step ST11, the dicing tape 105 is attached to the lower surface of the ring frame 106 with the adhesive surface facing upward. Then, the silicon wafer 108 is attached onto the dicing tape 105 in the central opening of the ring frame 106. That is, the dicing tape 105 is attached to the back surface 104 of the silicon wafer 108. As a result, one work set 200 in which the ring frame 106, the dicing tape 105, and the silicon wafer 108 are integrated is formed.

[0066] In the adhesive film attachment step ST12, an adhesive film 109 is attached to the entire surface 101 of the silicon wafer 108. Specifically, as shown in FIG. 1, the adhesive film 109 is attached to the surface 101 of the silicon wafer 108 separated into each chip 103. The adhesive film attachment step ST12 can be performed, for example, by using a reattaching device (not shown). In the adhesive film attachment step ST12, the adhesive film 109 is pressed and heated to be attached to the entire surface 101 of the silicon wafer 108 after grinding. The adhesive film 109 can be attached by conducting the electrodes to the wiring of the support substrate. For example, an acrylic adhesive film or a polyimide adhesive film can be used as the adhesive film 109. The adhesive film 109 and the dicing tape 105 may be attached to the silicon wafer 108 in a pre-laminate state. When the adhesive film 109 is attached to the entire surface 101 of the silicon wafer 108, the adhesive film attachment step ST12 is completed.

[0067] In the holding step ST13, the silicon wafer 108 is held on the chuck table 121 with the adhesive film 109 facing up. The holding step ST13 can be performed, for example, by using the groove processing device 2 of FIG. 2. Specifically, in the holding step ST13, as shown in FIG. 2, the work set 200 is placed on the chuck table 121 by a conveying mechanism (not shown) so that the silicon wafer 108 is positioned at the center of the chuck table 121. Then, the ring frame 106 around the silicon wafer 108 is clamped and fixed by the clamp unit 123. Then, the silicon wafer 108 is held on the chuck table 121 with the adhesive film 109 facing up. In this case, the silicon wafer 108 may be suction-held by negative pressure generated on the holding surface 21 via the dicing tape 105.

[0068] In the groove processing step ST14, a groove processing mechanism (laser processing unit 120) of a laser beam is used to process a processed groove 401 in the adhesive film 109 and the silicon wafer 108 along the street 102. The groove processing step ST14 can be performed, for example, by using the groove processing device 2 of Fig. 2. The groove processing step ST14 in which the processed groove 401 is processed by the laser processing unit 120 will be described with reference to Fig. 2.

[0069] In the groove processing step ST14, after performing alignment to align the silicon wafer 108 on the chuck table 121 with the irradiation position of the laser beam 400 by the laser beam irradiation unit 124 of the laser processing unit 120, the laser beam irradiation unit 124 performs laser processing by irradiating the silicon wafer 108 with a laser beam 400 having an absorptive wavelength along the street 102 from the surface 101 side of the silicon wafer 108, thereby forming a processed groove 401 along the street 102 in the adhesive film 109 on the street 102 and in the silicon wafer 108.

[0070] In the groove processing step ST14, when a laser beam 400 is irradiated along the street 102 to perform laser processing to form a processed groove 401, there is a problem that silicon contained in the silicon wafer 108 melts and scatters as silicon chips (debris), which then adhere to the surface 111 of the adhesive film 109. As a result, when the chips 103 are stacked, there is a risk that the silicon chips will cause erroneous connection between the electrodes of the chips 103 and the wiring or electrodes of the support substrate.

[0071] Therefore, in this embodiment, the chip removal step ST16 is performed after the groove processing step ST14. This makes it possible to remove silicon chips attached to the surface 111 of the adhesive film 109 even when the silicon wafer 108 is cut together with the adhesive film 109. Then, when the chips 103 are stacked, it is possible to prevent the electrodes of the chips 103 from being erroneously connected to the wiring or electrodes of the support substrate by the silicon chips, thereby making it possible to stack the chips 103 on which fine wiring is arranged.

[0072] After the groove processing step ST14, the chip removing step ST16 may be performed via the dividing step ST15. That is, the dividing step ST15 is performed when the grooves formed in the groove processing step ST14 do not completely cut the wafer.

[0073] In the dividing step ST15, the chip 103 is divided into individual chips 103 along the streets 102 (see FIG. 1). The dividing step ST15 can be performed, for example, by using an expanding device (not shown). In the dividing step ST15, for example, the ring frame 106 is held by a clamp or the like on a chuck table of the expanding device, and the chuck table and the clamp are raised and lowered relatively in the vertical direction, and the dicing tape 105 is expanded in the horizontal direction.

[0074] In the debris removal step ST16, a plasma gas 501 in which SF6 or CF4 is plasma-converted is sprayed onto at least the silicon debris adhering to the surface of the adhesive film 109 to remove the silicon debris. The debris removal step ST16 can be performed, for example, by using the debris removal device 1 of FIG. 3. Specifically, as shown in FIG. 3, in the debris removal step ST16, the control unit 80 controls the valve 411 to supply SF6 gas from the processing gas supply source 41 to the gas supply path 18 and guide it between the pair of plasma electrodes 51. The control unit 80 controls the plasma unit 50 to generate a plasma gas 501 in which the SF6 gas guided between the pair of plasma electrodes 51 is plasma-converted. The control unit 80 supplies the generated plasma gas 501 toward the holding surface 21 of the chuck table 20 in the vacuum chamber 10 to spray it onto the silicon debris adhering to the surface of the adhesive film 109 of the silicon wafer 108. This allows the silicon debris adhering to the surface 111 of the adhesive film 109 to be removed by remote plasma generated by the plasma gas 501. Furthermore, when the chips 103 are stacked, silicon debris is prevented from causing erroneous connection between the electrodes of the chips 103 and the wiring or electrodes of the supporting substrate, making it possible to stack the chips 103 having fine wiring arranged thereon.

[0075] Since silicon fluoride is generated by removing the silicon layer in the debris removal step ST16, the surface 111 of the adhesive film 109 is covered with a fluoride layer fluorinated by silicon fluoride. The fluoride layer generated in the debris removal step ST16 may be formed non-uniformly or have an uneven surface, which may cause inconvenience in processing the silicon wafer 108. Therefore, in the fluoride layer removal step ST17, after the debris removal step ST16, O2 gas that contains oxygen atoms and is plasmatized is sprayed onto the fluoride layer that was fluorinated on the surface 101 of the adhesive film 109 during the debris removal step ST16 in the vacuum chamber 10, and the fluoride layer is removed by plasma ashing.

[0076] The fluoride layer removal step ST17 can be performed, for example, by using the debris removal device 1 of FIG. 3. Specifically, as shown in FIG. 3, in the fluoride layer removal step ST17, the control unit 80 controls the valve 431 to supply O2 gas from the oxygen gas supply source 43 to the air supply path 18 and guide it between the pair of plasma electrodes 51. The control unit 80 controls the plasma unit 50 to generate oxygen plasma in which the O2 gas guided between the pair of plasma electrodes 51 is plasma-generated. The control unit 80 supplies the generated oxygen plasma toward the holding surface 21 of the chuck table 20 in the vacuum chamber 10, and sprays it against the silicon debris attached to the surface of the adhesive film 109 of the silicon wafer 108. As a result, in the debris removal step ST16, a gas containing oxygen atoms and plasma-generated gas is sprayed onto the fluoride layer fluorinated on the surface 111 of the adhesive film 109, and the fluoride layer is removed by reacting with fluorine by plasma ashing.

[0077] As described above, in this embodiment, the generated plasma gas 501 is supplied toward the holding surface 21 of the chuck table 20 in the vacuum chamber 10 and sprayed against silicon debris adhering to the surface 111 of the adhesive film 109 of the silicon wafer 108. This makes it possible to remove silicon debris adhering to the surface 111 of the adhesive film 109 when forming the processed groove 401 in the groove processing step ST14 by remote plasma using the plasma gas 501. As a result, when the chips 103 are stacked, it is possible to prevent the electrodes of the chips 103 from being erroneously connected to the wiring or electrodes of the support substrate by the silicon debris, and to stack the chips 103 on which fine wiring is arranged.

[0078] (Modification) As a modification of the above-described embodiment, for example, a cutting blade 131 may be used to machine a processed groove 401 in the adhesive film 109 and the silicon wafer 108 along the street 102. As shown in Fig. 5, the debris removal device 1 of the modification includes a chuck table 121, a holding surface 122, a clamp unit 123, a cutting blade 131, and a spindle 132. The configurations of the chuck table 121, the holding surface 122, and the clamp unit 123 are substantially similar to those of the above-described embodiment, and therefore description thereof will be omitted.

[0079] 5, the chip removal device 1 is equipped with a spindle 132 that serves as a rotation axis that is generally parallel to the holding surface 122 and generally perpendicular to the processing feed direction. An annular cutting blade 131 made of abrasive grains fixed with a binder is attached to one end of the spindle 132. A rotation drive source (not shown) such as a motor is connected to the other end of the spindle 132, and the cutting blade 131 attached to one end of the spindle 132 rotates by the power of this rotation drive source.

[0080] In the groove processing step ST14 of the embodiment of the modified example, as shown in FIG. 5, the cutting blade 131 is aligned with the street 102 of the silicon wafer 108, and is lowered to a depth capable of cutting the silicon wafer 108 on the radially outer side of the silicon wafer 108, and a full cut is performed. The silicon wafer 108 is cut and fed horizontally relative to the cutting blade 131, so that the cutting blade 131 cuts the adhesive film 109 and the silicon wafer 108, and a processed groove 401 is formed in the silicon wafer 108 along the street 102. When forming the processed groove 401, cutting water is supplied to the portion where the cutting blade 131 cuts into the silicon wafer 108, and silicon chips (cutting chips) discharged by the cutting blade 131 are removed from the silicon wafer 108. However, silicon chips (cutting chips) that are not washed away by the cutting water adhere to the upper surface of the adhesive film 109 attached to the upper surface of the silicon wafer 108. In the above embodiment, the cutting blade 131 is lowered to a depth where the silicon wafer 108 can be cut to perform a full cut, but this is not limited to the above. For example, the silicon wafer 108 may be half-cut by the cutting blade 131. When half-cutting, the dividing step ST15 is performed. In this modification, in the scrap removal step ST16, silicon scraps (cutting scraps) attached to the adhesive film 109 are removed.

[0081] The embodiments of the present invention are not limited to the above-mentioned embodiments and modifications, and may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea of ​​the present invention. Furthermore, if the technical idea of ​​the present invention can be realized in a different way due to technological progress or a different technology derived therefrom, the present invention may be implemented using that method. Therefore, the claims cover all embodiments that may be included within the scope of the technical idea of ​​the present invention. [Industrial Applicability]

[0082] As described above, the processing method of the silicon wafer 108 using the debris removal device 1 of the present invention can remove silicon debris adhering to the adhesive film 109 even when the silicon wafer 108 is cut together with the adhesive film 109. Therefore, it is particularly useful in the field of forming a silicon wafer 108 to which an adhesive film 109 is attached. [Explanation of symbols]

[0083] 1: Debris removal equipment, 2: Grooving equipment, 10: Vacuum chamber, 20: chuck table, 40: gas supply source, 41: processing gas supply source, 43: oxygen gas supply source, 50: plasma generating unit, 51: plasma generating electrode, 80: control unit, 100: silicon wafer, 102: street, 103: chip, 108: wafer, 109: adhesive film, 120: laser processing unit, 124: laser beam irradiation unit, 131: cutting blade, 200: work set, 401: machining groove, 501: plasma gas

Claims

1. A method for processing a silicon wafer, in which a plurality of chips having electrodes on a surface thereof are arranged and streets are formed between the chips, and the silicon wafer is processed along the streets, the method comprising the steps of: an adhesive film attaching step of attaching an adhesive film to the entire surface of the silicon wafer so as to electrically connect the electrodes to the wiring of a support substrate; a holding step of holding the silicon wafer on a chuck table with the adhesive film facing up; a groove machining step of machining grooves in the adhesive film and the silicon wafer along the streets using a cutting blade or a laser beam groove machining mechanism; After the groove processing step, SF is added to the silicon chips attached to at least the surface of the adhesive film. ６ or CF ４ and a debris removal process for removing the silicon debris by injecting a gas that has been converted into plasma from the silicon debris. A method for processing silicon wafers.

2. and a fluoride layer removal step of spraying a plasma gas containing oxygen atoms onto a fluoride layer formed on the surface of the adhesive film during the debris removal step in a vacuum chamber, thereby removing the fluoride layer by plasma ashing. The method for processing a silicon wafer according to claim 1.

3. The adhesive film is an anisotropic conductive film. The method for processing a silicon wafer according to claim 1.

4. The adhesive film is a non-conductive film. The method for processing a silicon wafer according to claim 1.

5. The adhesive film has a two-layer structure of an anisotropic conductive film and a non-conductive film. The method for processing a silicon wafer according to claim 1.

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