Chip manufacturing method and processing method

Abstract

To reduce the influence of burrs generated on a workpiece due to ablation processing on the bonding between a chip and the workpiece.SOLUTION: A method for manufacturing chips by dividing a workpiece having a substrate and an insulating film along a plurality of planned division lines includes a protective film forming step of forming a protective film in contact with an insulating film, a laser processing step of removing the protective film and at least part of the insulating film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulating film, a first plasma etching step of etching burrs generated outside the grooves at least in the width direction of the grooves during the laser processing step with plasmatized gas to remove the burrs, and a second plasma etching step of dividing the substrate by expanding the depths of the grooves from one surface to the other surface of the substrate in the thickness direction of the substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a chip manufacturing method for manufacturing chips by dividing a workpiece having a substrate with a plurality of planned division lines set on one surface thereof and an insulating film provided on the one surface or the other surface of the substrate along the plurality of planned division lines, and a processing method for processing the workpiece by plasma etching. [Background technology]

[0002] In the manufacture of semiconductor device chips, devices are formed in each rectangular area defined by a plurality of planned division lines set in a grid pattern on the surface of a wafer, and the wafer is then divided along each of the planned division lines to individualize the wafer into a plurality of semiconductor device chips (i.e., chips).

[0003] The wafer is divided, for example, by plasma etching. In order to form a mask in which each of the intended division lines is exposed during plasma etching, it is known that a water-soluble protective film is formed on the surface of the wafer and then the wafer is ablated by irradiating it with a laser beam having a wavelength that is absorbed by the wafer (see, for example, Patent Document 1).

[0004] Incidentally, a workpiece having a relatively thick (e.g., about 2 μm to 3 μm) insulator film formed of an oxide film, a nitride film, or the like, may be diced into chips in a manner that allows it to contact multiple devices, and then the insulator film in the chip may be bonded to an insulator film provided on a circuit board such as a logic circuit board (i.e., the object to be bonded), thereby bonding the chip to the object to be bonded.

[0005] In this manner, when a workpiece having a relatively thick insulating film for use in joining is to be divided by plasma etching along each of the intended dividing lines, for example, a water-soluble protective film is first formed on the insulating film, and then a laser beam for ablation processing is irradiated.

[0006] By irradiating the laser beam, a groove is formed in the thickness direction of the wafer, spanning the water-soluble protective film, the relatively thick insulator film, and a portion of the wafer near the surface, but burrs originating from the insulator film may occur on both sides of the width of the groove.

[0007] Immediately after the ablation process, the burrs may be formed protruding like spikes from the upper surface of the insulating film inside the water-soluble protective film. If the burrs remain on the chip, when the workpiece is divided into chips and finally bonded to the bonded object, the burrs may hinder surface contact between the chip and the bonded object, resulting in a bonding failure. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2016-207737 A Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of these problems, and aims to reduce the effect that burrs generated on a workpiece due to ablation processing by a laser beam have on the bonding between a chip and a bonded object. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a method for manufacturing chips by dividing a workpiece having a substrate having a plurality of planned division lines set on one surface thereof and an insulator film provided on the one surface or on another surface opposite to the one surface thereof, along the plurality of planned division lines to manufacture chips, the method comprising: a protective film forming step of forming a protective film in contact with the insulator film; a laser processing step after the protective film forming step of irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulator film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulator film; a first plasma etching step after the laser processing step of removing burrs generated outside the groove in at least the width direction of the groove during the laser processing step by etching the groove with plasma gas; and a second plasma etching step after the laser processing step of etching the substrate with plasma gas to extend the depth of the groove from the one surface to the other surface of the substrate in the thickness direction of the substrate, thereby dividing the substrate.

[0011] According to another aspect of the present invention, there is provided a method for manufacturing chips by dividing a workpiece having a substrate having a plurality of planned division lines set on one surface thereof and an insulating film provided on the one surface of the substrate along the plurality of planned division lines to manufacture chips, the method comprising the steps of: forming a protective film in contact with the insulating film; laser processing, after the protective film forming step, irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulating film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulating film; and after the laser processing step, removing the protective film and at least a portion of the insulating film that are present at positions corresponding to the plurality of planned division lines in the laser processing step. The present invention provides a method for manufacturing chips, comprising: a first plasma etching step of removing burrs generated outside the groove by etching the burrs with plasma gas; a second plasma etching step of extending the depth of the groove to a predetermined depth of the substrate corresponding to the finished thickness of the chip by etching the substrate with plasma gas after the laser processing step; a protective member attachment step of attaching a protective member to the insulator film after the second plasma etching step; and a grinding step of dividing the workpiece into chips by grinding the other surface of the substrate opposite to the one surface of the substrate until the substrate has the finished thickness after the protective member attachment step.

[0012] Preferably, the chip manufacturing method further includes a burr exposure step, after the laser processing step and before the first plasma etching step, of etching the protective film with plasmatized gas to recede the protective film outside the width direction of the groove and expose the burr.

[0013] Preferably, the chip manufacturing method further includes a burr exposure step, after the laser processing step and before the first plasma etching step, of irradiating the protective film with a laser beam along the intended division line, thereby retracting the protective film outside the width direction of the groove to expose the burr.

[0014] Preferably, the insulator film comprises silicon oxide and has a thickness of 0.1 μm or more.

[0015] Preferably, the insulating film is used to bond a chip produced by dividing the workpiece to an object to be bonded.

[0016] Preferably, the second plasma etching step is anisotropic etching that expands the depth of the grooves so that the length in the thickness direction of the substrate is greater than the length in the width direction of each of the dividing lines.

[0017] Preferably, the protective film formed in the protective film forming step has a thickness of 3 μm or more and 12 μm or less.

[0018] Preferably, when the burr exposing step is performed by etching with a plasmatized gas, the burr exposing step, the first plasma etching step, and the second plasma etching step are performed in the same chamber.

[0019] Preferably, when the burr exposing step is performed by irradiating a laser beam, the first plasma etching step and the second plasma etching step are performed in the same chamber.

[0020] According to yet another aspect of the present invention, there is provided a processing method for processing a workpiece having a substrate having a plurality of planned division lines set on one surface thereof and an insulating film provided on the one surface of the substrate or on the other surface opposite to the one surface thereof, the processing method comprising: a protective film forming step of forming a protective film in contact with the insulating film; a laser processing step of, after the protective film forming step, irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulating film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulating film; a first plasma etching step of, after the laser processing step, removing burrs generated outside the grooves in at least the width direction of the grooves during the laser processing step by etching the burrs with a plasmatized gas; and a second plasma etching step of, after the laser processing step, etching the substrate with a plasmatized gas to extend the depth of the grooves in the thickness direction of the substrate. Effect of the Invention

[0021] In the first plasma etching step in the chip manufacturing method according to one aspect of the present invention, burrs generated at least in the width direction of the groove outside the groove in the laser processing step are removed by etching with plasma gas. Therefore, the influence of the burrs on the bonding between the chip and the bonded object can be reduced compared to the case where the burrs generated on the workpiece due to the ablation processing are not removed. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a flow diagram of a method for manufacturing the device chip according to the first embodiment. [Diagram 2] FIG. 2(A) is a perspective view of the workpiece, and FIG. 2(B) is a cross-sectional view of the workpiece. [Diagram 3]FIG. 3(A) is a partial cross-sectional side view of the protective film forming process, FIG. 3(B) is a cross-sectional view of a workpiece on which a water-soluble protective film has been formed, and FIG. 3(C) is a partially enlarged view of FIG. 3(B). [Figure 4] 4(A) and 4(B) are partial cross-sectional side views showing the laser processing process. [Diagram 5] FIG. 4B is a partially enlarged view of FIG. [Figure 6] 1 is a partial cross-sectional side view of a plasma processing apparatus; [Figure 7] Figure 7(A) is a partial enlarged view of the laminate during the burr exposure process, Figure 7(B) is a partial enlarged view of the laminate during the first plasma etching process, and Figure 7(C) is a partial enlarged view of the laminate during the second plasma etching process. [Figure 8] FIG. 8(A) is a partially sectional side view showing a protective film removing step, and FIG. 8(B) is a partially enlarged view of the workpiece after the protective film removing step. [Figure 9] FIG. 9(A) is a diagram showing a bonding step, and FIG. 9(B) is a cross-sectional view of the device chip and the object to be bonded bonded to each other. [Figure 10] FIG. 11 is a flow diagram of a method for manufacturing a device chip according to the second embodiment. [Figure 11] FIG. 11 is a partial enlarged view of the workpiece after a second plasma etching step in the second embodiment. [Figure 12] FIG. 12(A) is a diagram showing a protective sheet attachment step, and FIG. 12(B) is a cross-sectional view of the workpiece and the protective sheet after the protective sheet attachment step. [Figure 13] FIG. 13(A) is a partially sectional side view showing the grinding step, and FIG. 13(B) is a sectional view of the workpiece and protective sheet after the grinding step. [Figure 14] FIG. 14(A) is a diagram showing a first modified example of the burr exposing step, and FIG. 14(B) is a diagram showing a second modified example of the burr exposing step. [Figure 15]Figure 15(A) is a cross-sectional view of a workpiece relating to the fourth modified example, Figure 15(B) is a cross-sectional view of the workpiece before the laser processing process of the fourth modified example, and Figure 15(C) is a cross-sectional view of the workpiece after the laser processing process of the fourth modified example. [Figure 16] FIG. 16(A) is a diagram showing a bonding step according to the fourth modified example, and FIG. 16(B) is a cross-sectional view of the device chip and the object to be bonded bonded to each other in the fourth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] (First embodiment) An embodiment according to one aspect of the present invention will be described with reference to the accompanying drawings. Fig. 1 is a flow diagram of a method for manufacturing a device chip 35 according to the first embodiment, in which a workpiece 11 (see Fig. 2(A)) is divided to manufacture a device chip (i.e., chip) 35 (see Figs. 8, 9(A), etc.).

[0024] In the first embodiment, the steps are performed in the following order: a protective film forming step S10, a laser processing step S20, a burr exposing step S30, a first plasma etching step S40, a second plasma etching step S50, a protective film removing step S60, and a bonding step S70.

[0025] First, the workpiece 11 will be described with reference to Fig. 2(A) and Fig. 2(B). Fig. 2(A) is a perspective view of the workpiece 11, and Fig. 2(B) is a cross-sectional view of the workpiece 11. The workpiece 11 has a disk-shaped substrate 13.

[0026] The substrate 13 has a wafer 15 such as single crystal silicon (Si). In this embodiment, the diameter of the wafer 15 is 8 inches (about 200 mm) and the thickness of the wafer 15 is about 725 μm, but the diameter and thickness of the wafer 15 are not limited to these values. A plurality of devices 17 are formed near a surface 15a of the wafer 15.

[0027] Each device 17 includes a functional layer having a wiring layer made of a conductive material such as a metal and an insulating layer made of an insulating material such as a low-k material, which are alternately stacked. Each device 17 is, for example, an integrated circuit (IC), but is not limited to an IC.

[0028] The wafer 15 and the multiple devices 17 constitute the above-mentioned substrate 13. A multiple number of planned division lines (streets) 19 are set in a lattice pattern on a surface (one surface) 13a of the substrate 13. An insulating film 21 is provided on substantially the entire surface 13a of the substrate 13 in a manner that contacts the surface 13a.

[0029] The insulator film 21 is used for bonding a device chip 35 manufactured by dividing the workpiece 11 along each of the plurality of planned dividing lines 19 to a bonded object 37 (see FIG. 9(A)). The insulator film 21 contains silicon oxide, silicon nitride, or silicon carbonitride.

[0030] In the manufacturing process of semiconductor chips, the insulator film 21 formed of silicon oxide is commonly referred to as a SiO film, the insulator film 21 formed of silicon nitride is commonly referred to as a SiN film, and the insulator film 21 formed of silicon carbonitride is commonly referred to as a SiCN film.

[0031] Unlike a relatively thin thermal oxide film of about 10 nm, the insulating film 21 is a relatively thick film having a thickness of 0.1 μm or more and 8 μm or less. The insulating film 21 of this embodiment has a thickness of about 4 μm.

[0032] The insulating film 21 is, for example, a silicon oxide film (for example, a SiO 2 film) formed by plasma CVD (Chemical Vapor Deposition) using TEOS (Tetraethyl Orthosilicate).

[0033] The insulating film 21 is relatively thick as a single layer among the multiple layers provided on the wafer 15. The insulating film 21 is formed by plasma CVD and then flattened by CMP (Chemical Mechanical Polishing).

[0034] Next, each step of the manufacturing method of the device chip 35 of the first embodiment will be described according to the flow shown in Fig. 1. First, a water-soluble protective film (protective film) 23 (see Fig. 3(B)) is formed on the workpiece 11 in a manner to contact the insulator film 21 (protective film forming step S10).

[0035] 3(A) is a partial cross-sectional side view of the protective film forming process S10. In the protective film forming process S10, a spinner device 10 is used. The spinner device 10 includes a disk-shaped spinner table 12, a first nozzle 12b for supplying a liquid water-soluble resin 23a, and a second nozzle 12c (see FIG. 8(A)) for supplying cleaning water 23b such as pure water.

[0036] In the protective film forming process S10, first, the back surface (other surface) 13b of the substrate 13 is suction-held by the holding surface 12a of the spinner table 12. Next, the spinner table 12 is rotated at high speed while liquid water-soluble resin 23a is supplied from a first nozzle 12b arranged above the center of the holding surface 12a.

[0037] The water-soluble resin 23a contains pure water as a main component, a polymer compound such as polyvinylpyrrolidone (PVP) or polyvinyl alcohol (PVA), and a light absorbing agent capable of absorbing ultraviolet light such as a cinnamic acid derivative or a benzophenone derivative.

[0038] After the supply of the water-soluble resin 23a and the rotation of the spinner table 12 are continued for a first time, the supply of the water-soluble resin 23a is stopped and the rotation of the spinner table 12 is further continued for a second time, thereby drying the water-soluble resin 23a.

[0039] As a result, a water-soluble protective film 23 having a predetermined thickness is formed on the insulating film 21. That is, a laminate 25 is formed having the workpiece 11 and the water-soluble protective film 23. An example of processing conditions in the protective film forming step S10 is shown below.

[0040] (When supplying water-soluble resin) Total supply amount of water-soluble resin: 20ml to 50ml Spinner table rotation speed: 300 rpm 1st time: 60s

[0041] (When water-soluble resin is dried) Spinner table rotation speed: 2000 rpm Second Time: 60s

[0042] FIG. 3(B) is a cross-sectional view of the workpiece 11 (that is, the laminate 25) on which the water-soluble protective film 23 is formed, and FIG. 3(C) is a partial enlarged view of an area A1 in FIG. 3(B).

[0043] The water-soluble protective film 23 formed in the protective film formation process S10 not only prevents debris generated in the subsequent laser beam ablation processing process from adhering to the substrate 13, but also functions as a mask for protecting the device 17, the insulator film 21, etc. in the subsequent plasma etching process.

[0044] Therefore, the water-soluble protective film 23 is thicker than the thickness (e.g., about 1.5 μm to 2.0 μm) of a water-soluble protective film 23 that is used only in laser beam ablation processing but is not intended for use in a plasma etching process.

[0045] The water-soluble protective film 23 has a thickness of, for example, 3 μm or more and 15 μm or less, more preferably 3 μm or more and 12 μm or less. In this embodiment, the water-soluble protective film 23 has a thickness of 8 μm. If the thickness of the water-soluble protective film 23 is less than 3 μm, there is a risk that the water-soluble protective film 23 will not function as a mask in the subsequent plasma etching process.

[0046] Furthermore, if the thickness of the water-soluble protective film 23 exceeds 15 μm, it will take more time to form the film, and the water-soluble protective film 23 will have a thickness greater than or equal to the thickness required for the subsequent steps, which will increase the amount of water-soluble resin 23a discarded in the protective film formation step S10, the protective film removal step S60, etc., and is therefore uneconomical.

[0047] Note that a photoresist film (i.e., a protective film) (not shown) used in a pre-process of the semiconductor manufacturing process may be formed on the insulating film 21 instead of the water-soluble protective film 23. The photoresist film can also be formed by using a spin coater having the above-mentioned spinner table 12 and first nozzle 12b.

[0048] The thickness of the photoresist used in the exposure step, which is a front-end step in the semiconductor manufacturing process, is usually about 0.1 μm to 0.5 μm, but in order to function as a mask, the thickness of the photoresist film is set to be 3 μm or more and 15 μm or less, similar to the water-soluble protective film 23, and more preferably 3 μm or more and 12 μm or less (e.g., 5 μm).

[0049] After the protective film forming step S10, a laser processing step S20 is performed in which a laser processing device 14 is used to form grooves 27 (see FIG. 4(B)) in the water-soluble protective film 23 and the insulator film 21. In the laser processing step S20, first, the rear surface 13b of the substrate 13 is suction-held by the holding surface 16a of the disk-shaped chuck table 16.

[0050] A condenser 18a of the laser beam irradiation unit 18 is disposed above the holding surface 32a. A pulsed laser beam L having a wavelength that is absorbed by the wafer 15 is irradiated from the condenser 18a toward the holding surface 32a.

[0051] For example, with the focal point P of the laser beam L positioned at the height of the top surface of the water-soluble protective film 23, the chuck table 16 is moved at a predetermined processing feed speed, so that the laser beam L is irradiated along the intended division line 19 (see Figure 4(A)).

[0052] As a result, a part of the wafer 15 near the surface 13a of the substrate 13 is ablated by the laser beam L, and at least a part of the water-soluble protective film 23 and the insulator film 21, which are present at positions corresponding to the intended dividing lines 19, are removed to form grooves 27. An example of processing conditions in the laser processing step S20 is shown below.

[0053] Wavelength: 355nm Average power output: 2.0W Spot diameter: 15μm Repetition frequency: 200kHz Machining feed speed: 100mm / s

[0054] FIG. 4(A) is a partial cross-sectional side view showing the laser processing step S20 when viewed in the XZ plane parallel to the processing feed direction (i.e., the X-axis direction) and the vertical direction (the Z-axis direction), and FIG. 4(B) is a partial cross-sectional side view showing the laser processing step S20 when viewed in the YZ plane parallel to the indexing feed direction (i.e., the Y-axis direction) and the Z-axis direction.

[0055] After performing the ablation process along one of the division lines 19, the chuck table 16 is moved along the Y-axis direction by a predetermined indexing feed amount corresponding to the pitch between adjacent division lines 19 in the Y-axis direction. Then, the ablation process is performed along the other division lines 19 in the same manner.

[0056] After the ablation process is performed along all the division lines 19 along one direction, the chuck table 16 is rotated by 90 degrees, and the ablation process is similarly performed along all the division lines 19 along the other direction perpendicular to the one direction. In this manner, grooves 27 are formed along each of all (a plurality of) division lines 19.

[0057] Fig. 5 is a partial enlarged view of region A2 in Fig. 4(B). After the laser processing step S20, burrs 29 are generated near side surfaces 27a of grooves 27. As shown in Fig. 5, some of burrs 29 are formed so as to be buried in water-soluble protective film 23 forming side surfaces 27a of grooves 27. That is, burrs 29 are generated at least on the outside of grooves 27 in width direction 27b of grooves 27.

[0058] 5, burrs 29 are also formed inside the grooves 27 (i.e., protruding from the side surfaces 27a of the water-soluble protective film 23 that define the grooves 27). The burrs 29 are formed, for example, by the material that constitutes the insulating film 21 melting and then solidifying. In one example, the burrs 29 are formed of silicon oxide (e.g., SiO2).

[0059] The groove 27 has a relatively narrow opening width 21a at the bottom of the insulator film 21. The opening width 21a is determined, for example, by the width of the groove 27 formed on the front surface 15a of the wafer 15 in the laser processing step S20 (i.e., the length in a direction perpendicular to the longitudinal direction of the planned dividing lines 19).

[0060] In contrast, groove 27 has a relatively wide opening width 23c at the top of water-soluble protective film 23. Opening width 23c is determined by the width of groove 27 formed in the uppermost surface of water-soluble protective film 23 in laser processing step S20.

[0061] In this embodiment, the side surface 27a of the groove 27 and the surface 13a of the substrate 13 (or the surface 15a of the wafer 15) form an angle θ of less than 90 degrees. The angle θ is preferably 30 degrees or more and 85 degrees or less, and more preferably 40 degrees or more and 60 degrees or less.

[0062] Such an angle θ of the side surface 27a can be realized by changing, in comparison with standard laser processing conditions, one or more of the average output, the processing feed rate, and the position of the focal point P. For example, under the standard processing conditions, the average output is 2.0 W, the processing feed rate is 200 mm / s, and the position of the focal point P is aligned with the uppermost surface of the water-soluble protective film 23.

[0063] In contrast, in order to form the above-mentioned angle θ, at least one of the following may be adopted: (i) the average power used is lowered or raised below the standard average power, (ii) the processing feed rate used is lowered or raised below the standard processing feed rate, and (iii) the position of the focal point P used is moved closer to the wafer 15 or farther from the wafer 15 than the top surface of the water-soluble protective film 23.

[0064] Specifically, at least one of the following is adopted: (i) the average output power used is 1.5 W or 2.5 W; (ii) the processing feed speed used is 100 mm / s or 300 mm / s; and (iii) the position of the focal point P used is 100 μm closer to the wafer 15 or farther from the wafer 15 than the top surface of the water-soluble protective film 23.

[0065] For example, (i) when the average output used is 1.5 W (ie, the average output used is lower than the standard average output), the above-mentioned angle θ is formed by the aperture width 21a being narrower than the aperture width 23c.

[0066] Furthermore, (i) when the average output used is set to 2.5 W (that is, the average output used is increased from the standard average output), the above-mentioned angle θ is formed by opening width 23c being wider than opening width 21a.

[0067] (ii) When the processing feed rate is set to 100 mm / s (i.e., the processing feed rate is lower than the standard processing feed rate), the energy per unit time supplied to the laminate 25 is high. Therefore, the opening width 23c is wider than the opening width 21a, and the above-mentioned angle θ is formed.

[0068] Also, (ii) when the processing feed rate is set to 300 mm / s (i.e., the processing feed rate is increased from the standard processing feed rate), the energy per unit time supplied to the laminate 25 is reduced. Therefore, the opening width 21a is narrower than the opening width 23c, and the above-mentioned angle θ is formed.

[0069] (iii) When the position of the focal point P to be used is moved 100 μm closer to the wafer 15 or farther from the wafer 15 than the top surface of the water-soluble protective film 23, the energy per unit time supplied to the laminate 25 is lowered. As a result, the opening width 21a becomes narrower than the opening width 23c, and the above-mentioned angle θ is formed.

[0070] In this manner, by having the side surface 27a of the groove 27 at the angle θ, the recession of the side surface 27a of the water-soluble protective film 23 becomes more significant in the burr exposure step S30 described later, compared to when the angle between the side surface 27a of the groove 27 and the surface 13a of the substrate 13 is 90 degrees or more, which has the advantage that the burrs 29 can be removed more reliably.

[0071] In the laser processing step S20, the insulator film 21 is substantially removed without remaining in the grooves 27, but a part of the insulator film 21 may remain in the grooves 27. Specifically, in a part of the planned dividing lines 19, no grooves 27 are formed in the wafer 15, and a thin part of the insulator film 21 remains. In this case, however, the insulator film 21 remaining in the grooves 27 will be removed in a subsequent step.

[0072] After the laser processing step S20, the workpiece 11 is subjected to plasma processing using the plasma processing device 20. First, the plasma processing device 20 will be described with reference to Fig. 6. Fig. 6 is a partial cross-sectional side view of the plasma processing device 20.

[0073] The plasma processing apparatus 20 is made of a conductive material such as metal, and includes an electrically grounded chamber 22. The interior of the chamber 22 forms a processing space 24 in which plasma processing is performed on a laminate 25.

[0074] A first opening 22a is formed in a side wall of the chamber 22, through which the stack 25 enters and exits the chamber 22. A gate valve 26 that opens and closes the first opening 22a is provided on the outside of the first opening 22a. The first opening 22a is opened and closed by the movement of a valve element of the gate valve 26.

[0075] A second opening 22b for exhaust is formed in the bottom wall of the chamber 22. A pipe 28 connected to an exhaust device 30 such as a vacuum pump is attached to the second opening 22b. When the exhaust device 30 is operated with the processing space 24 sealed, the processing space 24 is exhausted.

[0076] A disk-shaped chuck table 32 for suction-holding the laminate 25 is provided in the processing space 24. The chuck table 32 is an electrostatic chuck, and has a disk-shaped main body made of a dielectric material such as ceramics, and one or more electrodes (see the dashed line in FIG. 6) embedded inside the main body.

[0077] The upper surface of the chuck table 32 functions as a substantially flat holding surface 32a. The holding surface 32a is disposed, for example, substantially parallel to a horizontal plane. Below the chuck table 32, a lower electrode 34 having substantially the same shape as the chuck table 32 is provided.

[0078] A high-frequency power supply 38 is connected to the lower electrode 34 via a matching unit 36. The high-frequency power supply 38 (i.e., bias power) supplies power at a predetermined frequency to the lower electrode 34, thereby causing the gas in a plasma state containing ions and radicals to collide with the workpiece in a direction substantially along the vertical direction (i.e., a direction perpendicular to the holding surface 32a).

[0079] A cooling plate (not shown) is provided in contact with the lower electrode 34, and during plasma processing, the lower electrode 34 and the chuck table 32 are cooled by a refrigerant flowing inside the cooling plate, and the temperature of the holding surface 32a is controlled to a target temperature.

[0080] A disk-shaped gas ejection head 40 made of a conductive material such as metal is provided above the holding surface 32a. The gas ejection head 40 is disposed in a circular third opening 22c provided in the upper wall of the chamber 22. An annular bearing 42 is provided between the third opening 22c and the gas ejection head 40.

[0081] The gas ejection head 40 is disposed in the third opening 22c in a manner that allows it to move along the vertical direction via a bearing 42. At least a portion of the bearing 42 is formed of an insulating material, and electrically insulates the gas ejection head 40 from the chamber 22.

[0082] An elevation mechanism (not shown) is connected to the gas ejection head 40. The elevation mechanism is, for example, a moving mechanism having a ball screw. The elevation mechanism raises and lowers the gas ejection head 40 in the vertical direction, thereby adjusting the distance between the holding surface 32a and the lower surface 40a of the gas ejection head 40.

[0083] The gas ejection head 40 is electrically connected to a high-frequency power source 48 (i.e., source power) via a matching device 46. In this manner, the plasma processing apparatus 20 of the present embodiment is a dual-frequency type capacitively coupled plasma (CCP: Capacitively Coupled Plasma) processing apparatus, but may be an inductively coupled plasma (ICP: Inductively Coupled Plasma) processing apparatus instead.

[0084] The high frequency power supply 48 supplies power to the gas ejection head 40 at a frequency relatively higher than that of the high frequency power supply 38, and turns the gas supplied to the disk-shaped cavity 40b located inside the gas ejection head 40 into a plasma state.

[0085] The gas ejection head 40 has a plurality of through holes 40c penetrating from the lower surface 40a to the cavity 40b. The plurality of through holes 40c are arranged at approximately equal intervals on the lower surface 40a. The plasma gas that has been turned into a plasma state in the cavity 40b of the gas ejection head 40 is supplied to the processing space 24 through the plurality of through holes 40c.

[0086] A gas supply path 40e penetrating from the upper surface 40d to the cavity 40b is formed in the gas ejection head 40. The gas supply path 40e is connected via piping 44 to a first gas supply source 46a, a second gas supply source 46b, a third gas supply source 46c, and a fourth gas supply source 46d.

[0087] The first gas supply source 46a supplies a first gas (e.g., oxygen (O2) gas) for plasma processing to the gas ejection head 40 via the piping 44. The first gas supply source 46a includes a tank filled with the first gas, a valve such as an electromagnetic valve, and a flow control device such as an MFC (Mass Flow Controller) or an FCS (Flow Control System) (all not shown).

[0088] A second gas supply source 46b is also connected to the pipe 44. The second gas supply source 46b supplies a second gas for plasma processing (e.g., tetrafluoromethane (CF4) gas) to the gas ejection head 40 via the pipe 44. The second gas supply source 46b includes a tank filled with the second gas, a valve, and a flow rate control device (none of which are shown).

[0089] A third gas supply source 46c is also connected to the pipe 44. The third gas supply source 46c supplies a third gas for plasma processing (e.g., octafluorocyclobutane (C4F8) gas) to the gas ejection head 40 via the pipe 44. The third gas supply source 46c includes a tank filled with the third gas, a valve, and a flow rate control device (none of which are shown).

[0090] A fourth gas supply source 46d is also connected to the pipe 44. The fourth gas supply source 46d supplies a fourth gas for plasma processing (e.g., sulfur hexafluoride (SF6) gas) to the gas ejection head 40 via the pipe 44. The fourth gas supply source 46d includes a tank filled with the fourth gas, a valve, and a flow rate control device (none of which are shown).

[0091] In FIG. 6, gas is supplied to the gas ejection head 40 from each of the first gas supply source 46a, the second gas supply source 46b, the third gas supply source 46c, and the fourth gas supply source 46d, but the number of gas supply sources connected to the gas ejection head 40 may be changed as necessary.

[0092] When performing plasma processing on the laminate 25 (i.e., the workpiece 11) using the plasma processing apparatus 20, first, the gate valve 26 is opened and the laminate 25 is placed on the holding surface 32a of the chuck table 32 by a transport mechanism (not shown).

[0093] The laminate 25 is transported into the plasma processing device 20 in the form of a workpiece unit in which the laminate 25, ring frame 31, and dicing tape 33 are integrated by attaching a dicing tape 33 (see FIG. 8(A)) to the rear surface 13b of the substrate 13 and one surface of the ring frame 31 (see FIG. 8(A)).

[0094] Next, the gate valve 26 is closed and the laminate 25 is held by suction on the holding surface 32a. Thereafter, the height of the lower surface 40a of the gas ejection head 40 relative to the holding surface 32a is adjusted so as to obtain a distance suitable for plasma processing, and the exhaust device 30 is operated to reduce the pressure in the processing space 24.

[0095] Next, gas for plasma processing is supplied to the cavity 40b of the gas ejection head 40 from at least one of the first gas supply source 46a, the second gas supply source 46b, the third gas supply source 46c, and the fourth gas supply source 46d, and the high-frequency power supply 48 supplies a predetermined power to the gas ejection head 40.

[0096] The gas plasmatized in cavity 40b is supplied to processing space 24 via a plurality of through holes 40c. When the gas plasma reaches stack 25, stack 25 is subjected to plasma processing (etching, film formation, etc.).

[0097] Next, the burr exposure process S30 (see FIG. 7(A)), the first plasma etching process S40 (see FIG. 7(B)), and the second plasma etching process S50 (see FIG. 7(C)), each of which is performed using the plasma processing apparatus 20, will be described.

[0098] 7A is a partially enlarged view of the laminate 25 in a burr exposing step S30 performed after the laser processing step S20. In the burr exposing step S30, the water-soluble protective film 23 of the laminate 25 is etched with a gas plasma.

[0099] Specifically, the processing space 24 is maintained at approximately 10 Pa, and O2 gas or the like is supplied to the gas ejection head 40 from the first gas supply source 46a at a predetermined flow rate (e.g., 100 sccm), while 2000 W of power is supplied from the high frequency power supply 48 to the gas ejection head 40, and 100 W of power is supplied from the high frequency power supply 38 to the lower electrode 34, for 60 seconds.

[0100] In the burr exposing step S30, the water-soluble protective film 23 is isotropically etched by etching the water-soluble protective film 23 with oxygen radicals, oxygen ions, etc. That is, the water-soluble protective film 23 is isotropically reduced in thickness by ashing.

[0101] In the burr exposing step S30, the water-soluble protective film 23 retreats substantially uniformly (for example, by about 3 μm) to the outside of the width direction 27b of the groove 27, and the thickness is reduced substantially uniformly (for example, by about 3 μm) in the direction perpendicular to the surface 13a. In this manner, as a result of the selective ashing of the water-soluble protective film 23, the burrs 29 covered by the water-soluble protective film 23 are exposed.

[0102] However, in the burr exposure process S30, instead of ashing using oxygen plasma, a nitrogen plasma treatment in which plasma treatment is performed while supplying nitrogen (N2) gas from the first gas supply source 46a, or a fluorine plasma treatment in which plasma treatment is performed while supplying fluorine (F2) gas from the first gas supply source 46a, etc. may be adopted.

[0103] After the burr exposing step S30, a first plasma etching step S40 for removing the burrs 29 is performed using the same plasma processing apparatus 20 (i.e., in the same chamber 22). Fig. 7(B) is a partial enlarged view of the laminate 25 in the first plasma etching step S40.

[0104] Burrs 29 generated outside groove 27 in at least width direction 27b in laser processing step S20 are exposed from water-soluble protective film 23 in the above-mentioned burr exposure step S30, and therefore, in the first plasma etching step S40, etching is performed on the exposed burrs 29 with plasmatized gas.

[0105] Specifically, while maintaining the processing space 24 at approximately 10 Pa and supplying CF4 gas or the like from the second gas supply source 46b to the gas ejection head 40 at a predetermined flow rate (e.g., 100 sccm), a power of 4000 W is supplied from the high frequency power supply 48 to the gas ejection head 40, and a power of 400 W is supplied from the high frequency power supply 38 to the lower electrode 34, and this is carried out for 300 seconds.

[0106] In the first plasma etching step S40, the burrs 29 are etched with fluorine radicals, fluorine ions, or the like, so that the burrs 29 are completely removed from the laminate 25 (see the dashed line in FIG. 7(B)).

[0107] In the first plasma etching process S40, etching is performed in a direction perpendicular to the surface 13a by supplying power to the lower electrode 34, so that the burrs 29 are removed and the thicknesses of the water-soluble protective film 23 and the insulator film 21 that is not covered by the water-soluble protective film 23 are reduced.

[0108] In the first plasma etching step S40, for example, the thickness of the water-soluble protective film 23 is reduced by about 2 μm when removing the burrs 29 having a thickness of about 1 μm in the direction perpendicular to the surface 13a. The processing conditions in the first plasma etching step S40 are appropriately adjusted depending on the material of the insulator film 21 that causes the burrs 29.

[0109] After the first plasma etching step S40, a second plasma etching step S50 is performed using the same plasma processing apparatus 20 (ie, in the same chamber 22) to extend the depth of the grooves 27 in the thickness direction 13c of the substrate 13.

[0110] 7(C) is a partial enlarged view of the laminate 25 in the second plasma etching step S50. In the second plasma etching step S50, the wafer 15 of the substrate 13 is etched with plasmatized gas by the so-called Bosch process, thereby increasing the ratio of the depth of the groove 27 to the width of the groove 27 (i.e., the aspect ratio).

[0111] That is, the second plasma etching process S50 is anisotropic etching that expands the depth of the grooves 27 so that the length in the thickness direction 13c of the substrate 13 is greater than the width direction length of each of the planned division lines 19. By this anisotropic etching, the grooves 27 are expanded from the front surface 13a to the back surface 13b of the substrate 13, and the substrate 13 is cut by the expanded grooves 27.

[0112] In the second plasma etching step S50, the following steps (a), (b), and (c) are repeated in this order: (a) a thin film formation step of depositing a thin film substantially uniformly in the grooves 27 using a CF-based gas, (b) an anisotropic etching step of selectively etching the bottom of the grooves 27 by accelerating a fluorine-containing gas plasma by a voltage applied to the lower electrode 34, and (c) an isotropic etching step of isotropically etching the grooves 27 after the anisotropic etching step with the fluorine-containing gas plasma.

[0113] In the (a) thin film forming process, for example, a predetermined power is supplied from the high frequency power source 48 to the gas ejection head 40 while a C4F8 gas or the like is supplied from the third gas supply source 46c to the gas ejection head 40 at a predetermined flow rate, for 6 to 8 seconds. As a result, a thin film (not shown) having a thickness of 10 nm or less is formed substantially uniformly in the groove 27.

[0114] (b) In the anisotropic etching step, for example, while SF6 gas or the like is supplied to the gas ejection head 40 from the fourth gas supply source 46d at a predetermined flow rate, a predetermined power is supplied from the high frequency power supply 48 to the gas ejection head 40, and a predetermined power is supplied from the high frequency power supply 38 to the lower electrode 34, for about three seconds. As a result, the thin film on the sidewall of the groove 27 is selectively removed from the bottom of the groove 27 while leaving the thin film on the sidewall of the groove 27.

[0115] In the (c) isotropic etching step, for example, a predetermined power is supplied to the gas ejection head 40 from the high frequency power source 48 while SF6 gas or the like is supplied to the gas ejection head 40 from the fourth gas supply source 46d at a predetermined flow rate, for 5 to 7 seconds. This removes the thin film on the sidewall of the groove 27 and deepens the bottom of the groove 27.

[0116] After the (c) isotropic etching step, the process returns to the (a) thin film formation step. In this manner, by repeating (a), (b) and (c), the groove 27 is extended to the back surface 13b of the substrate 13 located on the opposite side to the front surface 13a of the substrate 13 (i.e., the back surface 15b of the wafer 15 located on the opposite side to the front surface 15a of the wafer 15).

[0117] In the second plasma etching step S50, the workpiece 11 is fully cut along each of the planned division lines 19, thereby dividing the workpiece 11 into a plurality of device chips 35. In the second plasma etching step S50, the single crystal silicon constituting the wafer 15 is mainly etched, but the insulator film 21 is also slightly etched.

[0118] However, the etching rate of the insulator film 21 in the second plasma etching step S50 is sufficiently low (for example, lower than 0.01 μm / min). In addition, the insulator film 21 on the device 17 remains covered with the water-soluble protective film 23. Therefore, in the second plasma etching step S50, the thickness of the insulator film 21 is substantially maintained.

[0119] After the second plasma etching step S50, the workpiece unit is transferred from the plasma processing device 20 to the above-mentioned spinner device 10, and the water-soluble protective film 23 is removed using the spinner device 10 (protective film removing step S60).

[0120] 8(A) is a partial cross-sectional side view showing the protective film removal step S60. In the protective film removal step S60, first, the substrate 13 is suction-held on the holding surface 12a via the dicing tape 33. Next, the spinner table 12 is rotated at high speed while cleaning water 23b such as pure water is supplied from a second nozzle 12c disposed above the center of the holding surface 12a.

[0121] After continuing the supply of cleaning water 23b and the rotation of spinner table 12 for a third time period, the supply of cleaning water 23b is stopped and the rotation of spinner table 12 is continued for a fourth time period to dry workpiece 11. An example of processing conditions in protective film removal step S60 is shown below.

[0122] (When cleaning water is supplied) Washing water supply: 300ml / min to 500ml / min Spinner table rotation speed: 2000 rpm Third Time: 60s

[0123] (When the workpiece 11 is dried) Spinner table rotation speed: 2000 rpm 4th Time: 60s

[0124] 8(B) is a partial enlarged view of the workpiece 11 near the groove 27 that reaches the back surface 13b after the protective film removal step S60. Note that in the protective film removal step S60, instead of the above-mentioned spin cleaning and drying, the water-soluble protective film 23 may be removed by plasma treatment similarly to the burr exposure step S30.

[0125] After the protective film removal step S60, the insulating film 21 is bonded to an object to be bonded 37 (see FIG. 9(A)). The object to be bonded 37 has, for example, a rectangular substrate made of single crystal silicon, and a predetermined circuit (not shown) such as a logic circuit is formed on the rectangular substrate.

[0126] As shown in Fig. 9(A), the bonded object 37 has an insulator film 39 formed so as to cover a predetermined circuit. The insulator film 39 is formed of the same material as the insulator film 21 of the workpiece 11 described above, and the insulator film 39 in this embodiment is a silicon oxide film (e.g., a SiO2 film). Fig. 9(A) is a diagram showing a bonding step S70.

[0127] In the bonding step S70, first, a hydrophilic treatment is performed on the insulator film 39 of the bonded object 37. The hydrophilic treatment is a treatment for forming a hydroxyl group (i.e., -OH) on the exposed surface of the insulator film 39. The hydrophilic treatment is performed, for example, by irradiating the exposed surface of the insulator film 39 with nitrogen plasma or ultraviolet light under atmospheric pressure.

[0128] After the hydrophilization treatment, the device chip 35 and the object to be bonded 37 are brought close to each other in a state where the insulator film 21 of the device chip 35 faces the insulator film 39 of the object to be bonded 37 until a load of, for example, about 10 kN acts on them. As a result, the device chip 35 and the object to be bonded 37 are bonded to each other.

[0129] In addition, when wiring (e.g., copper (Cu) wiring) included in the device 17 and wiring (e.g., copper wiring) included in a specified circuit of the object to be bonded 37 are directly connected in the bonding process S70 (i.e., hybrid bonding is performed), the temperature of the atmosphere in the bonding process S70 is set, for example, to 250°C or higher and 350°C or lower.

[0130] This bonding step S70 may be performed under atmospheric pressure or 5 The bonding may be performed in a reduced pressure atmosphere of less than Pa. Fig. 9(B) is a cross-sectional view of the device chip 35 and the object 37 to be bonded together.

[0131] In addition, after the bonding process S70, a via (e.g., a TSV (i.e., through-silicon via)) may be formed that penetrates the device chip 35 and the insulator film 39 of the object to be bonded 37, thereby electrically connecting the device chip 35 to a specified circuit of the object to be bonded 37.

[0132] In this embodiment, in the first plasma etching step S40, burrs 29 generated outside grooves 27 at least in width direction 27b of grooves 27 in the laser processing step S20 are removed by etching with plasmatized gas.

[0133] Therefore, compared to the case where burrs 29 generated on workpiece 11 due to ablation processing are not removed, it is possible to reduce the influence of burrs 29 on the bonding between device chip 35 and bonded object 37. As a result, for example, substantially the entire one surface of insulator film 21 located on the opposite side to device 17 can be bonded to insulator film 39.

[0134] Second Embodiment Next, a second embodiment will be described with reference to Fig. 10 to Fig. 14(B) Fig. 10 is a flow diagram of a method for manufacturing a device chip 35 according to the second embodiment.

[0135] In the second plasma etching process S50 of the second embodiment, the depth of the groove 27 is extended to a predetermined depth 27d in the substrate 13 corresponding to the finished thickness of the device chip 35 without fully cutting the workpiece 11 (i.e., the depth of the groove 27 is extended in the substrate 13 in the thickness direction 13c) (see Figure 11).

[0136] Thereafter, a protective sheet attaching step (protective member attaching step) S62 and a grinding step S64 are performed, followed by a bonding step S70. This point is different from the first embodiment, so a description of the contents common to the first embodiment will be omitted.

[0137] In the second plasma etching process S50 in the second embodiment, the depth of the groove 27 is kept at a predetermined depth 27d by reducing the number of repetitions of (a) the thin film formation process, (b) the anisotropic etching process, and (c) the isotropic etching process compared to the first embodiment.

[0138] 11 is a partial enlarged view of the workpiece 11 after the second plasma etching step S50 in the second embodiment. The predetermined depth 27d does not reach the back surface 13b of the substrate 13, and is, for example, at a position approximately half the thickness of the wafer 15 (i.e., the distance from the front surface 15a to the back surface 15b).

[0139] After the second plasma etching step S50, a protective film removing step S60 is performed (see FIG. 8(A)), followed by a protective sheet attaching step S62 in which a resin protective sheet (protective member) 41 is attached to the insulating film 21 of the workpiece 11. FIG. 12(A) is a diagram showing the protective sheet attaching step S62 which is performed using an attaching device 50.

[0140] The joining device 50 has a disk-shaped chuck table 52. The workpiece 11 is sucked and held by negative pressure on a holding surface 52a of the chuck table 52 via the dicing tape 33. A cylindrical feed roller 54 and a take-up roller 56 are provided above the holding surface 52a.

[0141] In the protective sheet attachment step S62, first, a long protective sheet 41 having a predetermined width larger than the diameter of the wafer 15 is pulled out between the delivery roller 54 and the take-up roller 56. Then, the pulled-out protective sheet 41 is pressed against the holding surface 52a by a cylindrical pressing roller 58.

[0142] Next, the chuck table 52 is moved in a predetermined direction 52b perpendicular to the longitudinal direction of the feed roller 54 in a plane substantially parallel to the holding surface 52a. As a result, the protective sheet 41 is attached to substantially the entire upper surface of the insulating film 21 exposed upward in the predetermined direction 52b.

[0143] The protective sheet 41 has a laminated structure including, for example, a base layer and an adhesive layer provided on one surface of the base layer. The base layer is made of a resin such as polyolefin (PO), and the adhesive layer is made of an ultraviolet (UV) curable resin.

[0144] It is to be noted that protective sheet 41 may have only a base layer without having an adhesive layer. In this case, protective sheet 41 is made of a thermoplastic resin such as polyolefin, and is attached to workpiece 11 by thermocompression bonding.

[0145] After the protective sheet 41 is attached, the protective sheet 41 is cut along the outer periphery of the workpiece 11 with a cutter (not shown) disposed above the holding surface 52a. As a result, the protective sheet 41 covering the insulating film 21 is cut into a circular shape.

[0146] After the protective sheet 41 is cut off, the dicing tape 33 is peeled off from the wafer 15, thereby separating the dicing tape 33 and the ring frame 31 from the wafer 15. Fig. 12(B) is a cross-sectional view of the workpiece 11 and the protective sheet 41 after the protective sheet attachment step S62.

[0147] After the protective sheet attachment process S62, a grinding device 60 is used to grind the back surface 13b of the substrate 13 (i.e., the back surface 15b of the wafer 15) until the substrate 13 reaches a finished thickness, thereby dividing the workpiece 11 into a plurality of device chips 35 (grinding process S64).

[0148] 13(A) is a partially sectional side view showing a grinding step S64 performed by using a grinding device 60. The grinding device 60 has a disk-shaped chuck table 62. The workpiece 11 is held by suction on the holding surface 62a of the chuck table 62 via a protective sheet 41 at the front surface 15a side of the wafer 15 such that the back surface 15b of the wafer 15 is exposed upward.

[0149] A grinding unit 64 is provided above the holding surface 62a. The grinding unit 64 has a cylindrical spindle 66. A motor (not shown) is provided near the upper end of the spindle 66, and a disk-shaped mount 66a is fixed to the lower end of the spindle 66.

[0150] An annular grinding wheel 68 is attached to the underside of the mount 66a. The grinding wheel 68 has an annular base 68a and a plurality of grinding stones 68b provided on the underside of the base 68a. The plurality of grinding stones 68b are arranged at approximately equal intervals in the circumferential direction of the base 68a.

[0151] In the grinding process S64, the chuck table 62, which holds the workpiece 11 by suction on the holding surface 62a via the protective sheet 41, is rotated at a predetermined rotation speed (e.g., 300 rpm), and the grinding unit 64 is fed for grinding at a predetermined speed (e.g., 5 μm / s) while the spindle 66 is rotated at a predetermined rotation speed (e.g., 3000 rpm).

[0152] In the grinding step S64, grinding water such as pure water is supplied at a predetermined flow rate from a grinding water supply nozzle (not shown) to the arc-shaped contact area where the grinding wheel 68b contacts the wafer 15. In this manner, the wafer 15 is thinned by in-feed grinding until the grooves 27 are exposed upward.

[0153] Fig. 13(B) is a cross-sectional view of the workpiece 11 and the protective sheet 41 after the grinding step S64. By thinning the wafer 15 to the finishing thickness, the workpiece 11 is divided into a plurality of device chips 35 along the grooves 27. After the grinding step S64, a bonding step S70 is performed as shown in Figs. 9(A) and 9(B).

[0154] In this embodiment as well, since the burrs 29 are removed in the first plasma etching step S40, the influence of the burrs 29 on the bonding between the device chip 35 and the bonded object 37 can be reduced compared to the case where the burrs 29 are not removed. As a result, for example, substantially the entire one surface of the insulator film 21 located on the opposite side to the device 17 can be bonded to the insulator film 39.

[0155] (First Modification) Next, a first modification of the burr exposing step S30 will be described with reference to Fig. 14(A). Fig. 14(A) is a diagram showing a first modification of the burr exposing step S30. In the first modification, the burr exposing step S30 is performed using the laser processing device 14 after the laser processing step S20 and before the first plasma etching step S40.

[0156] Specifically, the average output of the laser beam L is reduced and / or the spot diameter of the focal point P is increased, thereby lowering the energy density of the laser beam L to a level where the insulator film 21 and the wafer 15 are hardly processed by the laser beam L.

[0157] After reducing the energy density at the focal point P in this manner, the water-soluble protective film 23 is irradiated with the laser beam L along the intended division line 19, whereby the water-soluble protective film 23 is retracted outside the width direction 27b of the groove 27 to expose the burrs 29.

[0158] In the burr exposure process S30 of the first modified example, the water-soluble protective film 23 located on the intended division line 19 can be locally removed using a laser beam L, so that the film thickness itself of the water-soluble protective film 23 located other than the intended division line 19 remains substantially unchanged.

[0159] Therefore, instead of the thickness of the water-soluble protective film 23 removed in the burr exposure step S30 and the first and second plasma etching steps S40, S50 as in the first embodiment, a water-soluble protective film 23 having a thickness greater than the thickness of the water-soluble protective film 23 removed in the first and second plasma etching steps S40, S50 can be formed in the protective film formation step S10.

[0160] That is, the thickness of the water-soluble protective film 23 in the protective film forming step S10 can be reduced by the amount of the reduction in the water-soluble protective film 23 in the burr exposing step S30 (see FIG. 7(A)). This leads to a reduction in the consumption of the water-soluble resin 23a in the protective film forming step S10, a reduction in the film formation time, etc.

[0161] (Second Modification) Next, a second modification of the burr exposing step S30 will be described with reference to Fig. 14(B). Fig. 14(B) is a diagram showing a second modification of the burr exposing step S30. In the second modification, the burr exposing step S30 is also performed using a laser processing device 14.

[0162] Specifically, the average output of the laser beam L is reduced and / or the laser beam L is split into two, thereby lowering the energy density of the laser beam L to a level where the insulator film 21 and the wafer 15 are hardly processed by the laser beam L.

[0163] After reducing the energy density at the focal point P in this manner, the water-soluble protective film 23 is irradiated with the laser beam L along the intended division line 19, whereby the water-soluble protective film 23 is retracted outside the width direction 27b of the groove 27 to expose the burrs 29.

[0164] In the burr exposing step S30 of the second modified example, the water-soluble protective film 23 located on the intended dividing line 19 can also be locally removed by using the laser beam L. This leads to a reduction in the consumption of the water-soluble resin 23a in the protective film forming step S10, a reduction in the film formation time, etc., as in the first modified example.

[0165] (Third Modification) Although not shown, instead of plasma treatment and laser processing, the burr exposure process S30 may expose the burrs 29 from the water-soluble protective film 23 by ion milling using a beam of argon (Ar) ions.

[0166] (Fourth Modification) Next, a fourth modification will be described with reference to Fig. 15(A) to Fig. 16(B). Fig. 15(A) is a cross-sectional view of a workpiece 11 according to the fourth modification, and corresponds to Fig. 2(B) of the first embodiment.

[0167] The workpiece 11 of the fourth modified example has an insulating film 21 provided in contact with the back surface 13b of the substrate 13, rather than the front surface 13a of the substrate 13. In addition, in the protective film forming step S10, a water-soluble protective film 23 is formed on the insulating film 21, and in the laser processing step S20, the front surface 13a of the substrate 13 is suction-held by the chuck table 16 via the dicing tape 33.

[0168] Fig. 15(B) is a cross-sectional view of the workpiece 11 before the laser processing step S20 of the fourth modified example, which corresponds to Fig. 3(C) of the first embodiment. Fig. 15(C) is a partially cross-sectional side view of the workpiece 11 after the laser processing step S20 of the fourth modified example, which corresponds to Fig. 5 of the first embodiment.

[0169] In the fourth modified example, burrs 29 are generated at least on the outside of groove 27 in width direction 27b of groove 27. The steps after laser processing step S20 are the same as those in the above-mentioned embodiment. Any of the first and second embodiments and the first to third modified examples can be applied to the fourth modified example.

[0170] Fig. 16(A) is a diagram showing the bonding step S70 and corresponds to Fig. 9(A) of the first embodiment. Fig. 16(B) is a cross-sectional view of the device chip 35 and the object to be bonded 37 bonded to each other in the fourth modified example and corresponds to Fig. 9(B) of the first embodiment.

[0171] In addition, the structures, methods, etc. according to the above-described embodiments can be modified as appropriate without departing from the scope of the present invention. As long as the burr exposing step S30 is performed before the first plasma etching step S40, the order of the burr exposing step S30, the first plasma etching step S40, and the second plasma etching step S50 can be modified as appropriate.

[0172] For example, after the laser processing step S20, the depth of the groove 27 formed in the wafer 15 is expanded in the second plasma etching step S50, and then the burr exposure step S30 is performed, followed by the first plasma etching step S40, thereby reducing the effect of the burrs 29 on the bonding between the device chip 35 and the workpiece 37.

[0173] In addition, for example, after the laser processing step S20, a burr exposure step S30 is performed, and then the depth of the groove 27 formed in the wafer 15 is expanded in the second plasma etching step S50, and then the first plasma etching step S40 is performed, thereby reducing the effect of the burrs 29 on the bonding between the device chip 35 and the bonded object 37.

[0174] However, the burr exposing step S30 is not essential. The burr exposing step S30 may be omitted, and the thickness of the water-soluble protective film 23 may be reduced and the burrs 29 may be removed in the first plasma etching step S40.

[0175] However, since the first plasma etching step S40 is a step optimized for removing the burrs 29, the removal rate of the water-soluble protective film 23 in the first plasma etching step S40 is generally lower than the removal rate of the water-soluble protective film 23 in the burr exposing step S30. Therefore, the total processing time required for processing the workpiece 11 can be shortened by retracting the water-soluble protective film 23 in the burr exposing step S30.

[0176] Furthermore, the burr exposing step S30, the first plasma etching step S40, and the second plasma etching step S50 do not necessarily have to be performed in the same chamber 22, and may be performed in different chambers 22.

[0177] In the above-described embodiment and modified examples, a method for manufacturing the device chip 35 has been described in which the device chip 35 is manufactured by dividing the workpiece 11. However, the manufacturing method may also be interpreted as a processing method in which the workpiece 11 having the above-described insulator film 21 is processed by plasma etching. [Explanation of symbols]

[0178] 10: Spinner device 12: spinner table, 12a: holding surface, 12b: first nozzle, 12c: second nozzle 11: Workpiece 13: substrate, 13a: front surface (one side), 13b: back surface (other side), 13c: thickness direction 14: laser processing device, 16: chuck table, 16a: holding surface 15: wafer, 15a: front surface, 15b: back surface, 17: device, 19: planned division line 18: laser beam irradiation unit, 18a: condenser 20: Plasma processing equipment 21: insulating film, 21a: opening width 22: chamber, 22a: first opening, 22b: second opening, 22c: third opening 23: water-soluble protective film (protective film), 23a: water-soluble resin, 23b: cleaning water, 23c: opening width 24: processing space, 26: gate valve, 28: pipe section 25: Laminate 27: groove, 27a: side surface, 27b: width direction, 27d: predetermined depth 29: Bali 30: Exhaust system 32: chuck table, 32a: holding surface, 34: lower electrode, 36: matching device 31: Ring frame, 33: Dicing tape 35: device chip (chip), 37: object to be bonded, 39: insulating film 38: High frequency power supply 40: gas ejection head, 40a: lower surface, 40b: cavity, 40c: through hole 40d: top surface, 40e: gas supply path 41: Protective sheet (protective material) 42: bearing, 44: piping, 46: matching box, 48: high frequency power source 46a: first gas supply source, 46b: second gas supply source 46c: third gas supply source, 46d: fourth gas supply source 50: application device, 52: chuck table, 52a: holding surface, 52b: predetermined direction 54: delivery roller, 56: take-up roller, 58: pressure roller 60: grinding device, 62: chuck table, 62a: holding surface 64: grinding unit, 66: spindle, 66a: mount 68: grinding wheel, 68a: base, 68b: grinding stone A1, A2: Area, L: Laser beam, P: Focus point, θ: Angle S10: Protective film formation process, S20: Laser processing process, S30: Burr exposure process S40: first plasma etching step, S50: second plasma etching step S60: Protective film removal process, S62: Protective sheet attachment process (protective member attachment process) S64: Grinding process, S70: Joining process

Claims

1. A method for manufacturing chips by dividing a workpiece having a substrate on one surface of which a plurality of planned division lines are set, and an insulating film provided on the one surface or on another surface of the substrate opposite to the one surface, along the plurality of planned division lines, a protective film forming step of forming a protective film in contact with the insulating film; a laser processing step of, after the protective film forming step, irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulator film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulator film; a first plasma etching step of removing burrs generated in the laser processing step outside the groove at least in the width direction of the groove by etching the burrs with a plasmatized gas, after the laser processing step; a second plasma etching step of dividing the substrate by etching the substrate with a plasma gas after the laser processing step, thereby expanding the depth of the groove in the thickness direction of the substrate from the one surface to the other surface of the substrate; A method for manufacturing a chip, comprising:

2. A method for manufacturing chips by dividing a workpiece having a substrate on one surface thereof and an insulating film provided on the one surface of the substrate along the plurality of planned division lines, the method comprising the steps of: a protective film forming step of forming a protective film in contact with the insulating film; a laser processing step of, after the protective film forming step, irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulator film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulator film; a first plasma etching step of removing burrs generated in the laser processing step outside the groove at least in the width direction of the groove by etching the burrs with a plasmatized gas, after the laser processing step; a second plasma etching step of etching the substrate with a plasma gas after the laser processing step, thereby expanding the depth of the groove to a predetermined depth of the substrate corresponding to a finished thickness of the chip; a protective member attaching step of attaching a protective member to the insulator film after the second plasma etching step; a grinding step of dividing the workpiece into chips by grinding the other surface of the substrate opposite to the one surface of the substrate until the substrate has the finished thickness after the protective member attaching step; A method for manufacturing a chip, comprising:

3. 3. The method for manufacturing a chip as described in claim 1 or 2, further comprising a burr exposure step, which, after the laser processing step and before the first plasma etching step, etches the protective film with plasmatized gas to recede the protective film outside the width direction of the groove and expose the burr.

4. The method for manufacturing a chip as described in claim 1 or 2, further comprising a burr exposure step, which, after the laser processing step and before the first plasma etching step, irradiates the protective film with a laser beam along the intended division line, thereby retracting the protective film outside the width direction of the groove to expose the burr.

5. 3. The method for manufacturing a chip according to claim 1, wherein the insulating film contains silicon oxide and has a thickness of 0.1 [mu]m or more.

6. 6. The method for manufacturing a chip according to claim 5, wherein the insulating film is used for bonding a chip manufactured by dividing the workpiece to an object to be bonded.

7. The method for manufacturing a chip as described in claim 1 or 2, characterized in that the second plasma etching process is anisotropic etching which expands the depth of the groove so that the length in the thickness direction of the substrate is greater than the length in the width direction of each planned division line.

8. 3. The method for manufacturing a chip according to claim 1, wherein the protective film formed in the protective film forming step has a thickness of 3 [mu]m or more and 12 [mu]m or less.

9. 4. The method for manufacturing a chip according to claim 3, wherein the burr exposing step, the first plasma etching step, and the second plasma etching step are performed in the same chamber.

10. 5. The method of claim 4, wherein the first plasma etching step and the second plasma etching step are performed in the same chamber.

11. A processing method for processing a workpiece by plasma etching, the workpiece having a substrate on one surface of which a plurality of planned division lines are set, and an insulating film provided on the one surface of the substrate or on another surface located opposite to the one surface, the method comprising the steps of: a protective film forming step of forming a protective film in contact with the insulating film; a laser processing step of, after the protective film forming step, irradiating a laser beam along the plurality of planned division lines to remove the protective film and at least a portion of the insulator film that are present at positions corresponding to the plurality of planned division lines, thereby forming grooves in the protective film and the insulator film; a first plasma etching step of removing burrs generated in the laser processing step outside the groove at least in the width direction of the groove by etching the burrs with a plasmatized gas, after the laser processing step; a second plasma etching step of etching the substrate with a plasma gas after the laser processing step, thereby expanding the depth of the groove in the thickness direction of the substrate; A processing method comprising:

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