Method for processing a workpiece and method for manufacturing a semiconductor device

Abstract

This invention provides a workpiece processing method that enables proper hybrid bonding without causing oxidation or etching phenomena in the metal parts of the device, even when the process includes a cutting step using a cutting blade. [Solution] The method comprises a protective film forming step of forming a protective film B on the metal part 121 exposed on the surface of the workpiece, a cutting step of cutting with a cutting blade while supplying cutting fluid to the workpiece 10, and a protective film removal step of removing the protective film B, wherein in the protective film forming step, a protective film forming liquid containing a corrosion inhibitor is supplied to form the protective film B on the metal part 121.

Description

Technical Field

[0001] The present invention relates to a method for processing a workpiece and a method for manufacturing a semiconductor device.

Background Art

[0002] In recent years, with the high integration of devices, hybrid bonding in which two devices are directly bonded together and electrodes are connected to each other has begun to be adopted. In this hybrid bonding, since the surfaces of the devices are bonded together, there is a problem that if foreign matter adheres to the device surface, it causes poor bonding. Therefore, when performing hybrid bonding, compared with the conventional bonding via bumps, reduction of foreign matter adhesion after dividing the substrate on which the device is formed is more strongly desired.

[0003] Therefore, in order to reduce foreign matter adhesion after cutting more than before, a technique has been proposed by the present applicant to perform cleaning on the surface side of the device using a cleaning fluid and a polishing pad (see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the cutting process, since cutting water is supplied to the processing point where the workpiece is cut by the cutting blade, water hits the metal part that is exposed on the wafer surface and constitutes the electrode, and an oxidation / etching phenomenon occurs in the metal part, the height of the metal part changes, and in hybrid bonding, the electrodes are not correctly connected to each other, resulting in a problem of poor bonding.

[0006] The present invention has been made in view of the above facts, and its main technical problem is to provide a method for processing a workpiece and a method for manufacturing a semiconductor device that can perform proper hybrid bonding without causing oxidation or etching phenomena in the metal parts of the device, even when including a cutting process with a cutting blade. [Means for solving the problem]

[0007] To solve the above-mentioned main technical problems, the present invention provides a method for processing a workpiece, comprising: a protective film forming step of forming a protective film on a metal portion exposed on the surface of the workpiece; a cutting step of cutting the workpiece with a cutting blade while supplying cutting fluid to the workpiece; and a protective film removal step of removing the protective film, wherein in the protective film forming step, a protective film is formed on the metal portion by supplying a protective film forming liquid containing a corrosion inhibitor.

[0008] The cutting process and the protective film formation process may be performed simultaneously by including the protective film forming solution in the cutting fluid supplied to the machining point during the cutting process. Alternatively, the protective film removal process may be carried out by polishing the surface of the workpiece with a polishing pad to remove the protective film. Furthermore, the protective film removal process may be carried out by irradiating the surface of the workpiece with plasma to remove the protective film.

[0009] Furthermore, the present invention provides a method for manufacturing a semiconductor device, comprising dividing a substrate in which devices are formed in regions demarcated by a plurality of intersecting division lines to form device chips, and then bonding the device surfaces together, the method comprising: a protective film formation step of forming a protective film on the metal portion of the substrate exposed on the device; a cutting step of cutting the substrate with a cutting blade while supplying cutting water along the division lines of the substrate; a grinding step of thinning the surface of the substrate opposite to the surface on which the device is formed by grinding with a grinding wheel; a protective film removal step of removing the protective film; and a bonding step of bonding the device surfaces together, wherein the protective film formation step involves supplying a protective film forming liquid containing a corrosion inhibitor to form a protective film on the metal portion of the device. [Effects of the Invention]

[0010] The present invention relates to a method for processing a workpiece, comprising: a protective film forming step of forming a protective film on the metal portion exposed on the surface of the workpiece; a cutting step of cutting the workpiece with a cutting blade while supplying cutting fluid to the workpiece; and a protective film removal step of removing the protective film. In the protective film forming step, a protective film is formed on the metal portion by supplying a protective film forming liquid containing a corrosion inhibitor. Therefore, even if the method for processing a workpiece includes a cutting step with a cutting blade, the workpiece can be processed in a way that prevents oxidation and etching phenomena from occurring on the metal portion of the device, enabling proper hybrid bonding.

[0011] Furthermore, the present invention provides a method for manufacturing a semiconductor device, which involves dividing a substrate, each having a device formed in a region demarcated by a plurality of intersecting division lines, to form device chips, and then bonding the device surfaces together. This method comprises: a protective film formation step of forming a protective film on the metal portion of the substrate exposed on the device; a cutting step of cutting the substrate with a cutting blade while supplying cutting water along the division lines of the substrate; a grinding step of thinning the substrate by grinding the surface opposite to the surface on which the device is formed with a grinding wheel; a protective film removal step of removing the protective film; and a bonding step of bonding the device surfaces together. The protective film formation step involves supplying a protective film forming liquid containing a corrosion inhibitor to form a protective film on the metal portion of the device. Therefore, even if the semiconductor device manufacturing method includes a cutting step with a cutting blade, oxidation and etching phenomena can not occur on the metal portion of the device, and proper hybrid bonding can be performed to manufacture a semiconductor device. [Brief explanation of the drawing]

[0012] [Figure 1] A perspective view showing the wafer and annular frame F of the workpiece. [Figure 2] A schematic, enlarged cross-sectional view showing a part of the protective film formation process. [Figure 3] A partially enlarged cross-sectional view showing an embodiment in which a protective film is formed on the metal part 121 of the device. [Figure 4] (a) Perspective view showing an embodiment of the cutting process, (b) Enlarged cross-sectional view of a portion of the wafer in which cutting grooves have been formed by the cutting process. [Figure 5] (a) A schematic overall perspective view showing the protective film removal device, and (b) A schematic side view showing a partial cross-section of an embodiment of the protective film removal process. [Figure 6] A schematic side view showing a cross-sectional portion illustrating another embodiment of the protective film removal process. [Figure 7] A schematic side view showing a cross-sectional portion illustrating yet another embodiment of the protective film removal process. [Figure 8]A schematic perspective view illustrating an embodiment of the grinding process. [Figure 9] A schematic side view showing a cross-sectional portion of an embodiment of the bonding process. [Modes for carrying out the invention]

[0013] Hereinafter, embodiments relating to a workpiece processing method and a semiconductor device manufacturing method constructed based on the present invention will be described in detail with reference to the attached drawings.

[0014] Figure 1 shows a wafer 10, which is an example of a workpiece processed by the present invention. The wafer 10 is a substrate on which devices 12 are formed in each of the regions demarcated by a plurality of intersecting division lines 14 on its surface 10a. The illustrated substrate is a semiconductor substrate, and is formed of silicon (Si), for example, but the present invention is not limited thereto, and may be a substrate of other semiconductors, such as a SiC substrate.

[0015] As can be seen from the enlarged perspective view of device 12 shown on the right side of Figure 1 (see the area enclosed by the dashed line), multiple metal parts 121 constituting electrodes are exposed on the surface of device 12. These metal parts 121 are made of, for example, copper (Cu). Note that the enlarged perspective view of device 12 shown in Figure 1 schematically shows the number and arrangement of the metal parts 121 for illustrative purposes and is not limited to the number and arrangement shown. Furthermore, the metal constituting the metal parts 121 is not limited to copper, but may be made of, for example, nickel (Ni) or cobalt (Co).

[0016] In carrying out the workpiece processing method of this embodiment, as shown in Figure 1, an annular plate-shaped frame F having an opening Fa capable of accommodating a wafer 10 is prepared, the surface 10a of the wafer 10 is positioned facing upward in the center of the opening Fa, and an adhesive tape T is attached to the back surface of the frame F and the back surface 10b of the wafer 10 to form a single unit, thereby holding the wafer 10 with the frame F.

[0017] (Protective Film Forming Process) In the processing method of the workpiece of this embodiment, first, a protective film forming process for forming a protective film on the metal part 121 exposed on the surface 10a of the wafer 10 is carried out. The protective film forming process is carried out by transporting the above-mentioned wafer 10 to a protective film forming apparatus 20 (only a part is shown) shown in FIG. 2. The protective film forming apparatus 20 includes a chuck table 22 configured to hold and rotatably support the wafer 10, and a supply nozzle 24 connected to a protective film forming liquid supply source (not shown) and configured to supply a protective film forming liquid W toward the chuck table 22. The wafer 10 is transported to the protective film forming apparatus 20, placed on the chuck table 22, and sucked and held. Next, the supply nozzle 24 is positioned above the wafer 10. Then, while rotating the chuck table 22 in the direction indicated by the arrow R1, the protective film forming liquid W is dropped or injected from the supply nozzle 24. At this time, the supply nozzle 24 may be swung horizontally above the wafer 10. As a result, the protective film forming liquid W diffuses on the surface 10a of the wafer 10 to cover the metal part 121 constituting the electrode on the device 12. As a result, as shown in FIG. 3, a protective film B is formed on the metal part 121.

[0018] The protective film forming liquid W is a liquid containing a so-called anticorrosive agent, and is formed by, for example, including the anticorrosive agent exemplified below in pure water.

[0019] As a corrosion inhibitor, it is preferable to use, for example, a heteroaromatic ring compound having three or more nitrogen atoms in the molecule and having a fused ring structure, or a heteroaromatic ring compound having four or more nitrogen atoms in the molecule. Furthermore, it is preferable that the aromatic ring compound contains a carboxyl group, a sulfo group, a hydroxyl group, or an alkoxy group. Specifically, it is preferable to use tetrazole or a tetrazole derivative, triazole or a triazole derivative, and benzotriazole or a benzotriazole derivative. Examples of tetrazole or tetrazole derivatives that can be used as a corrosion inhibitor include those in which an alkyl group is introduced that does not have substituents on the nitrogen atoms forming the tetrazole ring and whose functional group included as a derivative is a substituent selected from the group consisting of a sulfo group, an amino group, a carbamoyl group, a carbamide group, a sulfamoyl group, and a sulfonamide group, or at least one substituent selected from the group consisting of a hydroxyl group, a carboxyl group, a sulfo group, an amino group, a carbamoyl group, a carbamide group, a sulfamoyl group, and a sulfonamide group.

[0020] Furthermore, examples of triazoles or triazole derivatives that can be used as corrosion inhibitors include those that do not have substituents on the nitrogen atom forming the triazole ring, and in which a substituent selected from the group consisting of a hydroxyl group, carboxyl group, sulfo group, amino group, carbamoyl group, carbonamide group, sulfamoyl group, and sulfonamide group is introduced as a functional group, or an alkyl group or aryl group substituted with at least one substituent selected from the group consisting of a hydroxyl group, carboxyl group, sulfo group, amino group, carbamoyl group, carbonamide group, sulfamoyl group, and sulfonamide group.

[0021] Furthermore, examples of benzotriazoles or benzotriazole derivatives that can be used as corrosion inhibitors include those that do not have substituents on the nitrogen atom forming the benzotriazole ring, and in which a substituent selected from the group consisting of hydroxyl, carboxyl, sulfo, amino, carbamoyl, carbamide, sulfamoyl, and sulfonamide groups is introduced as a functional group, or an alkyl group or aryl group substituted with at least one substituent selected from the group consisting of hydroxyl, carboxyl, sulfo, amino, carbamoyl, carbamide, sulfamoyl, and sulfonamide groups.

[0022] By supplying the protective film forming liquid W containing the above-described corrosion inhibitor to the surface 10a side of the wafer 10 and allowing it to diffuse, a protective film B made of copper oxide (Cu2O) film, or a protective film B formed from one or more corrosion inhibitor components, is formed on the metal part 121 made of Cu, as shown in Figure 3. Since the protective film B formed on the metal part 121 is complexly formed, the protective film B will not be removed even if it comes into contact with a liquid containing water supplied in each subsequent process. Note that the protective film formation process is not limited to the embodiment described above. For example, the protective film B may be formed on the metal part 121 of the device 12 simply by supplying the protective film forming liquid W to the surface 10a side of the wafer 10 without rotating the chuck table 22. Alternatively, the protective film B may be formed on the metal part 121 of the device 12 by applying it to the surface 10a of the wafer 10 using a well-known brush (pen brush, roller brush, etc.) instead of using the protective film forming apparatus 20 described above. Furthermore, the concentration of the corrosion inhibitor contained in the protective film forming liquid W is preferably 0.1 ppm to 100 ppm at the point of contact with the wafer W, which is the workpiece, and more preferably 0.1 ppm to 10 ppm. By setting it within this range, the protective film B is quickly formed on the metal part 121, and the protective film forming liquid W is not used in excess.

[0023] (cutting process) After the protective film formation process described above has been carried out, a cutting process is performed in which the wafer 10 is cut with a cutting blade while cutting water is supplied to the wafer 10. This cutting process is carried out, for example, by the following procedure.

[0024] After performing the protective film formation process described above and forming the protective film B on the metal portion 121 of the wafer 10, the wafer is transported to the cutting apparatus 30 (only a portion is shown) as shown in Figure 4(a).

[0025] The cutting apparatus 30 shown in Figure 4(a) comprises a chuck table (not shown) for suction holding of a wafer 10 and a cutting means 31 for cutting the wafer 10 held by the chuck table. The chuck table is rotatably configured and includes an X-axis moving means (not shown) for machining feed of the chuck table in the direction indicated by arrow X in the figure. The cutting means 31 comprises a spindle 33 arranged in the Y-axis direction indicated by arrow Y in the figure and rotatably held in a spindle housing 32, an annular cutting blade 34 held at the tip of the spindle 33, and a blade cover 35 covering the cutting blade 34, and includes a Y-axis moving means (not shown) for indexing feed of the cutting blade 34 in the Y-axis direction. The blade cover 35 has cutting fluid introduction sections 351, 351 formed therein and is connected to a cutting fluid supply source (not shown). The cutting fluid introduction sections 351, 351 are connected to a pair of cutting fluid supply nozzles 36 (the opposite side is not visible) which are arranged to sandwich the cutting blade 34 from both sides. When cutting fluid L is introduced from the cutting fluid introduction sections 351, 351, the cutting fluid L is supplied from the pair of cutting fluid supply nozzles 36 to the processing point where the wafer 10 is cut by the cutting blade 34. The cutting fluid L is, for example, pure water, and the spindle 33 is rotationally driven by a spindle motor (not shown). The cutting edge that constitutes the outer circumference of the cutting blade 34 is made up of a so-called grinding wheel in which abrasive grains, such as diamond, are dispersed and fixed by a binder such as metal, resin, or ceramics.

[0026] In carrying out the cutting process of this embodiment, first, the wafer 10 is placed on the chuck table of the cutting device 30 with its surface 10a facing upwards and held in place by suction, and the predetermined division line 14 of the wafer 10 is aligned in the X-axis direction, and the cutting blade 34 is aligned with it. Next, the cutting blade 34, which is rotating at high speed, is positioned on the division line 14 aligned in the X-axis direction and cuts from the surface 10a side, and the chuck table is machined and fed in the X-axis direction to form a cutting groove 100. Furthermore, the cutting blade 34 of the cutting means 31 is indexed and fed onto a division line 14 adjacent in the Y-axis direction to the division line 14 in which a cutting groove 100 has been formed, and cutting is performed to form a cutting groove 100 in the same manner as above. By repeating these steps, cutting grooves 100 are formed along all division lines 14 along the X-axis direction. Next, the chuck table is rotated 90 degrees to align the direction perpendicular to the direction in which the cutting groove 100 was previously formed with the X-axis direction, and the above-described cutting process is performed on all the division lines 14 that have been newly aligned with the X-axis direction, thereby forming cutting grooves 100 along all the division lines 14 formed on the wafer 10. This completes the cutting process of this embodiment. The cutting groove 100 formed at this time is a so-called half-cut groove that does not reach the back surface 10b of the wafer 10, as shown in Figure 4(b), and the depth of the cutting groove 100 is set to a dimension slightly larger than the finished thickness dimension when a device chip is formed using this wafer 10.

[0027] In the above cutting process, cutting fluid L is supplied to the processing point to be processed by the cutting blade 34. At this time, a protective film B is formed on the metal part 121 that was exposed on the device 12 of the wafer 10, so that the metal part 121 is not oxidized or etched by the cutting fluid L supplied to the processing point.

[0028] (Protective film removal process) After the above cutting process has been performed, a protective film removal process is carried out to remove the protective film B formed on the metal part 121 before transporting the wafer 10 to the next process, for example, a hybrid bonding process in which the surfaces of the wafers are bonded together. The protective film removal process can be carried out by various methods, but typically it can be carried out by the protective film removal apparatus 40 shown in Figures 5(a) and (b).

[0029] The protective film removal apparatus 40 is a device that removes the protective film B by polishing the surface 10a of the wafer 10, and as shown in Figure 5, it has a main body 41, a holding unit 42 installed on the main body 41, a polishing cleaning fluid supply unit 43, a polishing pad 44, a lifting unit (not shown) that raises and lowers the polishing cleaning fluid supply unit 43 in the vertical direction, and a rotary motor (not shown) that rotates the holding unit 42 around an axis parallel to the Z-axis direction.

[0030] The apparatus body 41 is provided with an opening 41a on its upper surface. The holding unit 42 holds the wafer 10 that has been machined in the above-described cutting process and is installed in the opening 41a of the apparatus body 41. The holding unit 42 is disc-shaped, and the holding surface 421 (see Figure 5(b)) parallel to the horizontal direction for holding the wafer 10 is formed from a porous ceramic or the like that has good ventilation. The holding surface 421 of the holding unit 42 is connected to a suction source (not shown), and the wafer 10 placed on the holding surface 421 is sucked and held by the suction source.

[0031] The polishing and cleaning fluid supply unit 43 supplies polishing fluid to the wafer 10 held in the holding unit 42. The polishing and cleaning fluid supply unit 43 is installed on the upper surface of the main body 41 of the apparatus, is formed in a tubular shape extending horizontally, and is positioned to swing freely around its base end. The base end of the polishing and cleaning fluid supply unit 43 is rotated around an axis parallel to the vertical direction by a motor (not shown). As the polishing and cleaning fluid supply unit 43 rotates around its base end, its tip passes over the wafer 10 held in the holding unit 42. The polishing and cleaning fluid supply unit 43 also moves up and down between a lowered position where its tip is close to the surface 10a of the wafer 10 held in the holding unit 42 and an elevated position above the lowered position.

[0032] The polishing and cleaning fluid supply unit 43 has a first polishing and cleaning fluid supply passage 451 and a second polishing and cleaning fluid supply passage 461, both independent of each other. The first polishing and cleaning fluid supply passage 451 supplies a first polishing and cleaning fluid 45 as a polishing fluid for polishing the wafer 10 held by the holding unit 42, and extends along the longitudinal direction of the polishing and cleaning fluid supply unit 43.

[0033] The first polishing and cleaning fluid supply passage 451 is connected to the first polishing and cleaning fluid supply source 453 via an on-off valve 452, and the first polishing and cleaning fluid 45 is supplied from the first polishing and cleaning fluid supply source 453. The first polishing and cleaning fluid supply passage 451 is supplied from the tip of the polishing and cleaning fluid supply unit 43 onto the surface 10a of the wafer 10 held by the holding unit 42 by the polishing and cleaning fluid supply unit 43 being positioned in a lowered position by a lifting unit and swinging around its base end. In the illustrated embodiment, the first polishing and cleaning fluid 45 is a slurry consisting of an acidic or alkaline solution and abrasive particles. The abrasive particles are composed of silica particles or the like.

[0034] The second polishing liquid supply passage 461 supplies a second polishing liquid 46 to the wafer 10 held by the holding unit 42, as a polishing liquid different from the first polishing liquid 45. The second polishing liquid supply passage 461 extends along the longitudinal direction of the polishing liquid supply unit 43. The second polishing liquid supply passage 461 is connected to the second polishing liquid supply source 463 via an on / off valve 462, and the second polishing liquid 46 is supplied from the second polishing liquid supply source 463. The second polishing liquid supply passage 461 is supplied from the tip of the polishing liquid supply unit 43 onto the surface 10a of the wafer 10 held by the holding unit 42 by the polishing liquid supply unit 43 being positioned in a lowered position by the lifting unit and swinging around its base end. In this embodiment, the second polishing liquid 46 consists of pure water and a cleaning solution.

[0035] The polishing pad 44 contacts the wafer 10 to which the first and second polishing and cleaning fluids 45 and 46 are supplied from the polishing and cleaning fluid supply unit 43, thereby polishing and cleaning the wafer 10. The polishing pad 44 is formed in the shape of a disc with a diameter smaller than that of the wafer 10, and in the illustrated embodiment, it is made of a material such as nonwoven fabric or foamed urethane. The polishing pad 44 is supported at the tip of the polishing and cleaning fluid supply unit 43 so as to be rotatable around an axis parallel to the vertical direction, and when the polishing and cleaning fluid supply unit 43 is positioned in the lowered position, it can contact the surface 10a of the wafer 10 which is held by suction on the holding surface of the holding unit 42. As shown in Figure 5(b), the polishing pad 44 communicates with the first and second polishing and cleaning fluid supply passages 451 and 461 and has an opening on its lower surface to supply the first and second polishing and cleaning fluids 45 and 46 supplied from the first and second polishing and cleaning fluid supply passages 451 and 461 to the surface 10a of the wafer 10.

[0036] The protective film removal device 40 has generally the configuration described above. In the protective film removal process, which is performed after the cutting process, the wafer 10 that has been cut in the cutting process is transported to the protective film removal device 40, and the back surface 10b of the wafer 10 is placed on the holding surface 421 of the holding unit 42 via tape T and held by suction, and the polishing cleaning liquid supply unit 43 is lowered to a predetermined lowered position.

[0037] In the protective film removal process of this embodiment, as shown in Figure 5(b), the on / off valve 452 is opened for a predetermined time to supply the first polishing cleaning liquid 45 from the first polishing cleaning liquid supply source 453 to the surface 10a of the wafer 10 through the first polishing cleaning liquid supply passage 451 and the polishing pad 44, while the holding unit 42 is rotated around its axis to swing the base end of the polishing cleaning liquid supply unit 43 and bring the polishing pad 44 into contact with the surface 10a of the wafer 10.

[0038] As a result, the first polishing and cleaning solution 45 flows from the center to the outer edge on the surface 10a of the wafer 10, and the polishing pad 44 slides on the surface 10a of the wafer 10, polishing and cleaning the surface 10a of the wafer 10. Next, after rotating the holding unit 42 for a predetermined time to supply the first polishing and cleaning solution 45 through the first polishing and cleaning solution supply passage 451, the on / off valve 452 is closed to stop the supply of the first polishing and cleaning solution 45.

[0039] As described above, after polishing and cleaning the surface 10a of the wafer 10 with the first polishing cleaning solution 45, the surface 10a of the wafer 10 is polished with a polishing pad 44 while supplying a second polishing cleaning solution 46, which is different from the first polishing cleaning solution 45, to the surface 10a of the wafer 10 to clean it. More specifically, for a predetermined time, the on / off valve 462 is opened and the second polishing cleaning solution 46 from the second polishing cleaning solution supply source 463 is supplied to the surface 10a of the wafer 10 through the second polishing cleaning solution supply passage 461 and the polishing pad 44, while the holding unit 42 is rotated around its axis and the base end of the polishing cleaning solution supply unit 43 is oscillated to bring the polishing pad 44 into contact with the surface 10a of the wafer 10. Then, the second polishing and cleaning liquid 46 flows over the surface 10a of the wafer 10 from the center outward, and the polishing pad 44 slides over the surface 10a of the wafer 10, polishing and cleaning the surface 10a of the wafer 10. After this cleaning is performed for a predetermined time, the holding unit 42 is rotated and the second polishing and cleaning liquid 46 is supplied through the second cleaning liquid supply passage 461. Then, the rotation of the holding unit 42 and the oscillation of the polishing and cleaning liquid supply unit 43 are stopped, the on / off valve 462 is closed to stop the supply of the second polishing and cleaning liquid 46, the tip of the polishing and cleaning liquid supply unit 43 is moved away from above the holding unit 42, and the holding unit 42 is raised to the raised position. By performing the polishing and cleaning process described above, the protective film B formed on the metal portion 121 of the device 12 on the surface 10a of the wafer 10 is removed, exposing the metal portion 121 that constitutes the electrode of the device 12, thus completing the protective film removal process and the workpiece processing method of this embodiment.

[0040] According to the workpiece processing method described above, even if the process includes a cutting step in which cutting is performed while supplying cutting water L to the workpiece (wafer 10), oxidation and etching phenomena will not occur in the metal parts of the device. This allows for proper hybrid bonding when bonding the wafers 10 together to form a stacked wafer, or when dividing the wafers 10 to form device chips and then bonding the two devices together. In the protective film removal apparatus 40 described above, two types of polishing liquids, namely the first polishing cleaning liquid 45 and the second polishing cleaning liquid 46, are supplied to polish the surface 10a of the wafer 10, but the present invention is not limited to this, and the protective film may be removed using only one type of polishing liquid.

[0041] In the embodiment described above, a protective film formation process is performed in which a protective film B is formed on the metal part 121 by supplying a protective film forming liquid W containing an anticorrosion agent to the surface 10a side of the wafer 10 using the protective film forming apparatus 20 described above. Subsequently, even if grinding water L is supplied to the processing point on the wafer 10 during the cutting process, the metal part 121 is prevented from oxidizing or etching occurs on the metal part 121. However, the present invention is not limited to this. For example, in a cutting apparatus 30 that performs the cutting process, the protective film forming liquid W containing the anticorrosion agent described above may be mixed with the cutting water L introduced from the cutting water introduction section 351, 351 and supplied to the processing point in the cutting process from the cutting water supply nozzle 36. This makes it possible to form a protective film B on the metal part 121 of the device 12 of the wafer 10 without using the protective film forming apparatus 20 described above, and in this case, the protective film formation process is performed simultaneously with the cutting process.

[0042] The protective film removal step included in the workpiece processing method of the invention is not limited to the method of polishing the surface 10a of the wafer 10 with the protective film removal device 40 described above, but may be carried out in other forms. For example, the wafer 10 after the cutting process may be transported to the polishing device 50 (only a part is shown) shown in Figure 6 to carry out the protective film removal step.

[0043] The polishing apparatus 50 shown in Figure 6 comprises at least a polishing unit 51 for polishing the wafer 10 and a holding unit 52 for holding the wafer 10. The polishing unit 51 comprises a rotating shaft 54 ​​rotated by a rotary motor (not shown), a polishing wheel 541 disposed at the lower end of the rotating shaft 54, and a polishing pad 542 mounted on the lower surface of the polishing wheel 541. It is configured to allow the introduction of polishing liquid (slurry) S from a polishing liquid supply means (not shown) via a path 54a (shown by a dashed line) formed in the axis of the rotating shaft 54. The polishing liquid S can be any well-known polishing liquid, for example, formed by mixing appropriate abrasive particles into an acidic or alkaline solution. The holding unit 52 comprises a chuck table 53 whose rotating shaft 521 is rotated by a rotary motor (not shown). The chuck table 53 comprises a holding surface 531 made of a porous material that allows air to pass through, and a frame portion 532 surrounding the holding surface 531. The frame portion 532 is connected to a suction source (not shown), and by operating the suction source, negative pressure is generated on the holding surface 531.

[0044] When performing the protective film removal process using this polishing apparatus 50, a tape T1 having the same shape as the wafer 10 is prepared and attached to the back surface 10b of the wafer 10. Next, the tape T1 side of the wafer 10 is placed on the chuck table 53 of the holding unit 52, and negative pressure is generated on the holding surface 531 to attract and hold it. Then, the chuck table 53 is rotated at a predetermined rotational speed, and the polishing unit 51 is positioned on the wafer 10. The rotation shaft 54 ​​is rotated by a drive motor (not shown), and the surface 10a of the wafer 10 is polished by the polishing pad 542 while supplying slurry S for a predetermined time. This polishing process also makes it possible to remove the protective film B formed on the metal part 121 of the device 12 of the wafer 10.

[0045] Furthermore, the protective film removal process of the present invention can also be carried out using a protective film removal apparatus 60 (only a portion is shown) as shown in Figure 7, which utilizes a plasma generator. In particular, if a Cu2O film is formed as a protective film B on the metal part 121 of the device 12 during the protective film formation process, the surface can be activated and the protective film B removed using the protective film removal apparatus 60 described below. When removing the protective film B using the illustrated protective film removal apparatus 60, the wafer 10 held on the frame F is transported to the protective film removal apparatus 60 via a tape T that has been cut in the cutting process.

[0046] The protective film removal apparatus 60 shown in Figure 7 comprises a chuck table 61 for holding the wafer 10 on which the cutting groove 100 has been formed by the cutting process described above, a suction member 62 for holding the semiconductor chip C manufactured by a separate chip manufacturing method on the wafer 10 held on the chuck table 61, and a plasma generator 63 for generating atmospheric pressure plasma, and is configured to also perform the bonding process described later simultaneously. The chuck table 61 is configured to hold the wafer 10 by suction by connecting its holding surface to a suction source (not shown).

[0047] Then, as shown in Figure 7, the back surface 10b of the wafer 10 is held in place on the chuck table 61 by suction via tape T, and the frame F is held in place by clamps (not shown). As a result, the wafer 10 is fixed to the chuck table 61 with its front surface 10a exposed facing upwards.

[0048] Next, on the wafer 10 side, a device 12 to which the semiconductor chip C will be bonded is selected. The suction member 62 is grounded and configured to communicate with a suction source 64. When performing the protective film removal process of this embodiment, the suction member 62 suctions and holds the semiconductor chip C, which has been transported to a predetermined storage location in advance, from its back side. That is, the semiconductor chip C is held by the suction member 62 with the surface Ca side, which is the bonding surface, exposed downwards. The suction member 62 then places the held semiconductor chip C above the device 12 to which it will be bonded.

[0049] The plasma generator 63 is connected to a plasma gas supply source 65 that supplies a rare gas such as argon or helium, and a high-frequency power supply 66. The tip 63a of the plasma generator 63 is positioned between a semiconductor chip C held by a suction member 62 and a predetermined device 12 on the wafer 10 below it. Furthermore, the plasma generator 63 generates atmospheric pressure plasma P using the rare gas and high-frequency power and irradiates it in the vertical direction from its tip.

[0050] As a result, atmospheric pressure plasma P is irradiated onto the surface Ca of the semiconductor chip C, activating the surface Ca of the semiconductor chip C. Simultaneously, the same atmospheric pressure plasma P is irradiated onto the surface 12a of a predetermined device 12 on the wafer 10, removing the protective film B formed on the metal portion 121 of the surface 12a of the device 12, and activating the semiconductor (silicon) portion and the metal portion 121 that constitute the device 12. Thus, the protective film removal apparatus 60 using plasma makes it possible to remove the protective film B formed in the protective film formation process and activate the surface of the device 12. Here, the surface Ca of the device side of the semiconductor chip C and the surface 12a of the device 12 on the wafer 10 are exposed with silicon (Si) forming the device and copper forming the metal portion 121 that functions as an electrode. As a result of the above activation, nitride films such as SiON and SiN, and oxide films such as SiO2 are formed on the surface Ca of the semiconductor chip C and the surface 12a of the device 12, so that the bonding process described later can be suitably carried out (this bonding process will be explained later). As described above, if the protective film B is formed of a Cu2O film, the protective film B is properly removed in the process of activating the surface Ca of the semiconductor chip C and the surface of the device 12 in preparation for bonding the semiconductor chip C and the device 12 using the protective film removal apparatus 60 described above. In this way, the protective film removal process can also be suitably carried out by using the protective film removal apparatus 60 including the plasma generator 63.

[0051] In the protective film removal process described above, an example was described in which the protective film B formed on the metal part 121 was removed by irradiating it with atmospheric pressure plasma P using a protective film removal device 60, and at the same time, the semiconductor (silicon) part and the metal part 121 constituting the device 12 were activated. However, for example, the protective film removal process of the present invention may also be carried out by vacuum plasma treatment, in which ionized ions, electrons, and radicals generated in a plasma state are brought into contact with the surface Ca on the device side of the semiconductor chip C and the surface 12a of the device 12 on the wafer 10 after the processing space has been made into a vacuum state. Alternatively, the protective film removal process of this embodiment may be carried out by applying UV treatment, in which low-wavelength ultraviolet (UV) light is irradiated onto the surface Ca on the device side of the semiconductor chip C and the surface 12a of the device 12 on the wafer 10.

[0052] The workpiece processing method of the present invention is not limited to the configuration described above. More specifically, in the description of the embodiments described above, it was explained that the workpiece processing method of this embodiment comprises a protective film formation step, a cutting step, and a protective film removal step. However, the method is not limited to comprising only these three steps, and it is not excluded to add other processing steps in addition to these three steps to constitute the workpiece processing method. For example, a grinding step may be included after the cutting step and before the protective film removal step to grind and thin the back surface 10b of the wafer 10. Also, as described with reference to Figures 5 and 6, after supplying a polishing liquid and polishing the surface 10a of the wafer 10 with a polishing pad to remove the protective film B, atmospheric pressure plasma P may be supplied to the surface of each device 12 using the protective film removal apparatus 60 described with reference to Figure 7 in order to activate the surface 12a of the device 12.

[0053] Next, embodiments relating to a method for manufacturing a semiconductor device constructed according to the present invention will be described. The semiconductor device manufacturing method described below is a method for manufacturing a semiconductor device in which a substrate, in which devices are formed in regions demarcated by a plurality of intersecting division lines, is divided to form device chips, and then the device surfaces are bonded together.

[0054] The semiconductor device manufacturing method of this embodiment includes the steps that constitute the workpiece processing method described above, and detailed explanations of the steps already described in the description of the above embodiment will be omitted as appropriate. The workpiece processed in the semiconductor device manufacturing method of this embodiment described below is the wafer 10 described above with reference to Figure 1 in the workpiece processing method, and is a wafer in which a plurality of devices 12 are partitioned by division lines 14 and formed on the surface 10a. Then, a single semiconductor device is manufactured by bonding the device surfaces of a device chip manufactured from the wafer 10 and a semiconductor chip manufactured from a semiconductor wafer not shown (for example, semiconductor chip C shown in Figure 7 above) together by performing so-called hybrid bonding.

[0055] (Protective film formation process) In carrying out the semiconductor device manufacturing method of this embodiment, a protective film formation step is performed to form a protective film on the metal portion exposed on the device on the substrate. This protective film formation step is carried out in the same manner as the protective film formation step in the workpiece processing method described above with reference to Figure 2, and a detailed explanation is omitted. In this protective film formation step, a protective film forming liquid W containing a corrosion inhibitor can be supplied and applied to the surface 10a side of the wafer 10 by the various methods described above, thereby forming the protective film B on the metal portion 121.

[0056] (cutting process) Next, a cutting process is performed in which the cutting line is cut by a cutting blade while supplying the cutting fluid L described above along the planned division line. This cutting process can also be performed in the same way as the cutting process in the workpiece processing method described with reference to Figure 4, and cutting is performed from the surface 10a side of the wafer 10 to form the cutting groove 100 shown in Figure 4(b). In this cutting process, since a protective film B is formed on the metal part 121 of the device 12 of the wafer 10 in advance, even if cutting fluid L is supplied to the processing point where cutting is performed, oxidation or etching of the metal part 121 of the device 12 is prevented.

[0057] (Grinding process) In the semiconductor device manufacturing method of this embodiment, a grinding process described below is performed after the cutting process described above in order to divide the wafer 10 and form a device chip. In the cutting process described above, tape T was attached to the back surface 10b of the wafer 10 and the annular frame F to hold the wafer 10 in the frame F. However, when performing the grinding process described below, tape T2 (see Figure 8) is attached to the front surface 10a side of the wafer 10 in advance, and the tape T on the back surface 10b is removed together with the frame F to expose the back surface 10b side.

[0058] As described above, the wafer 10 on which the cutting process has been performed is transported to the grinding apparatus 70 shown in Figure 8 (only a portion is shown). As shown in Figure 8, the grinding apparatus 70 is equipped with a grinding means 72 for grinding and thinning the back surface 10b of the wafer 10 which is held by suction on the chuck table 71. The grinding means 72 is equipped with a rotary spindle 73 which is rotated by a rotary drive mechanism (not shown), a wheel mount 74 attached to the lower end of the rotary spindle 73, and a grinding wheel 75 attached to the lower surface of the wheel mount 74, and a plurality of grinding wheels 76 are arranged in an annular shape on the lower surface of the grinding wheel 75.

[0059] The wafer 10 is transported to the grinding apparatus 70 shown in Figure 8, and placed on the chuck table 71 with its back surface 10b facing upwards and held in place by suction. Next, the rotary spindle 73 of the grinding means 72 is rotated at, for example, 3000 rpm in the direction indicated by arrow R3 in Figure 8, while the chuck table 71 is rotated at, for example, 300 rpm in the direction indicated by arrow R4. Then, grinding water is supplied onto the back surface 10b of the wafer 10 by a grinding water supply means (not shown), and the grinding wheel 76 is brought into contact with the back surface 10b of the wafer 10, and the grinding wheel 75 is fed downwards at, for example, a grinding feed rate of 1 μm / second, as indicated by arrow R5 in the figure. In this process, the thickness of the wafer 10 can be measured using a measuring instrument (not shown) while grinding is carried out. Once a predetermined amount of the back surface 10b of the wafer 10 has been ground and the wafer 10 has reached a predetermined thickness, the grinding means 70 is stopped, and after cleaning, drying, and other processes, the grinding process for grinding the back surface 10b of the wafer 10 is completed. By performing the above grinding process, the cutting grooves 100 formed by the cutting process are exposed on the back surface 10b side (not shown). As a result, the wafer 10 is divided into device chips for each device 12.

[0060] (Protective film removal process) After the grinding process described above is performed, the tape T is attached to the back surface 10b of the wafer 10, the wafer 10 is held by the annular frame F described above, and the protective film removal process is performed to remove the protective film B. The protective film removal process in this embodiment can be performed in the same manner as the protective film removal process of the workpiece processing method described above based on Figures 5 to 7. Although details will not be explained here, in this embodiment, when performing the protective film removal process described based on Figures 5 to 7, the wafer 10 is divided into individual device chips for each device 12, which is different from the workpiece processing method described above. Furthermore, if the protective film B formed in the protective film formation process is formed from one or more types of corrosion inhibitor components, it is convenient to remove the protective film B by polishing the surface 10a of the wafer 10 with a polishing pad while supplying polishing liquid, as described above based on Figures 5 and 6. Furthermore, if the protective film B is formed of a Cu2O film, it is possible to activate the surface 12a of the device 12 and remove the protective film B using the plasma generator 63 of the protective film removal apparatus 60 described above based on Figure 7. Therefore, it is preferable to perform the protective film removal process using the protective film removal apparatus 60 shown in Figure 7.

[0061] Furthermore, if a protective film B is formed on the metal part 121 of the device 12 from one or more corrosion inhibitor components during the protective film formation process, and the protective film B is removed by a polishing pad while supplying polishing liquid during the protective film removal process, a corrosion inhibitor that forms a Cu2O film on the metal part 121 may be mixed into the polishing liquid supplied during the protective film removal process. In this way, even if the protective film B is removed during the protective film removal process, oxidation or etching of the metal part 121 by the supplied polishing liquid is prevented, and the Cu2O film can be removed by supplying atmospheric pressure plasma P using the plasma generator 63 described above to activate the surface 12a of the device 12, thereby protecting the metal part 121 until just before bonding the device surfaces together to manufacture the semiconductor device. From the above viewpoint, it is most preferable to form a protective film B consisting of a Cu2O film during the protective film formation process and to perform the protective film removal process using the protective film removal apparatus 60 shown in Figure 7.

[0062] (Bonding process) As described above, once the protective film removal process is performed, a bonding process is carried out to bond the device surfaces of the device chips together. The device surface of the device chip is the surface 12a on which the metal part 121 is formed in the device chip formed by dividing the device 12 described above. As described above, typically, when the protective film B is formed of a Cu2O film, the protective film removal process described with reference to Figure 7 is carried out. Furthermore, even if the protective film B is formed from one or more types of corrosion inhibitor components and the protective film B is removed by polishing, the surface 12a of the device 12 is activated by supplying atmospheric pressure plasma P to the device surface using the protective film removal apparatus 60 shown in Figure 7. At this time, as described in Figure 7, a semiconductor chip C formed by dividing a semiconductor wafer similar to wafer 10 is positioned so that the device surfaces face each other on the opposite side of the device chip 12 to be bonded, and atmospheric pressure plasma P is supplied to both device surfaces to activate the opposing device surfaces.

[0063] Then, as shown in Figure 9, the surface Ca of the semiconductor chip C and the divided device 12 are placed facing each other and bonded together. That is, in this bonding process, as shown in the figure, the suction member 62 that holds the semiconductor chip C whose surface Ca has been activated by the protective film removal device 60 moves downward as indicated by arrow R6. As a result, the surface Ca of the semiconductor chip C is pressed against the activated surface 12a of the device 12 located below it. This results in a hybrid bond between the surface Ca of the semiconductor chip C and the surface 12a of the device 12, and the electrode Cb of the semiconductor chip C and the metal part 121 of the device chip 12 are also connected. In the above explanation, it was stated that the protective film removal process can be performed by irradiating the surface Ca of the semiconductor chip C and the surface 12a of the device 12 with atmospheric pressure plasma P using the protective film removal device 60 shown in Figure 7, and that these processes can be activated. However, it is also possible to activate the surface 12a of the device 12 and the surface Ca of the semiconductor chip C by performing the vacuum plasma treatment and UV treatment described above on the surface Ca of the semiconductor chip C and the surface 12a of the device 12. Therefore, the bonding process described above can also be suitably realized by performing the vacuum plasma treatment and UV treatment instead of irradiating with atmospheric pressure plasma P using the protective film removal device 60.

[0064] As described above, the activation of the surface Ca of semiconductor chip C and the surface 12a of device 12 results in the formation of nitride films such as SiON and SiN, as well as oxide films such as SiO2, in addition to copper. Therefore, when the surface Ca of semiconductor chip C and the surface 12a of device 12 are pressed together, bonds are formed between the oxide films (or nitride films), and these bonds firmly connect the surface Ca of semiconductor chip C and the surface 12a of device 12.

[0065] In the semiconductor device manufacturing method of this embodiment, a protective film B is formed on the metal portion 121 of the device 12 by applying a protective film forming liquid W containing a corrosion inhibitor during the protective film formation process. Therefore, even if cutting or grinding is performed while the protective film B is formed, the metal portion 121 is protected by the protective film B, preventing oxidation or etching of the metal portion 121. Furthermore, since the protective film B is removed before the bonding process is carried out, no irregularities occur on the bonding surface, and a semiconductor device is formed in which the device surfaces of the two device chips are firmly bonded to each other.

[0066] In the embodiments described above, an example was shown in which the electrodes of the device 12 were formed of copper (Cu). However, the present invention is not limited thereto, and the metal part 121 may be formed of nickel (Ni), cobalt (Co), or even other metals capable of forming electrodes. [Explanation of Symbols]

[0067] 10: Wafer 12: Devices 14: Planned division line 20: Protective film forming device 22: Chuck Table 24: Supply nozzle 30: Cutting equipment 31:Cutting means 32: Spindle Housing 33: Spindle 34: Cutting blade 35: Blade cover 351: Cutting water introduction part 36: Cutting fluid supply nozzle 40:Protective film removal device 41: Main unit of the device 41a: Opening hole 42: Holding Unit 421: Holding surface 43: Polishing and cleaning fluid supply unit 44: Polishing pad 45: First polishing and cleaning solution 451: First polishing and cleaning fluid supply channel 452: Shut-off valve 453: Polishing and cleaning fluid supply source 46: Second polishing and cleaning solution 461: Second polishing and cleaning fluid supply channel 462: Shut-off valve 463: Source of polishing and cleaning fluid 50: Polishing equipment 51: Polishing Unit 52: Holding Unit 53: Chuck Table 54: Rotation axis 541: Polishing Wheel 542: Polishing pad 60:Protective film removal device 61: Chuck Table 62: Suction component 63: Plasma generator 64:Suction source 65: Plasma gas supply source 70: Grinding equipment 71: Chuck Table 72: Grinding methods 100: Cutting groove C: Semiconductor chips F: Frame L: Grinding water P: Atmospheric pressure plasma T, T1, T2: Tape W: Protective film forming solution

Claims

1. A method for processing a workpiece, A protective film formation step in which a protective film is formed on the metal part exposed on the surface of the workpiece, A cutting process in which cutting is performed with a cutting blade while supplying cutting fluid to the workpiece, A protective film removal step to remove the protective film, Equipped with, In the protective film formation process, A method for processing a workpiece, characterized by forming a protective film on the metal part by supplying a protective film-forming liquid containing a corrosion inhibitor.

2. A method for processing a workpiece according to claim 1, A method for processing a workpiece, characterized in that the cutting process and the protective film formation process are carried out simultaneously by including the protective film forming liquid in the cutting fluid supplied to the processing point during the cutting process.

3. A method for processing a workpiece according to claim 1, The method for processing a workpiece is characterized in that the protective film removal step involves removing the protective film by polishing the surface of the workpiece with an abrasive pad.

4. A method for processing a workpiece according to claim 1, The protective film removal step is a method for processing a workpiece, characterized by removing the protective film by irradiating the surface of the workpiece with plasma.

5. A method for manufacturing a semiconductor device, which involves dividing a substrate in which devices are formed in regions demarcated by multiple intersecting division lines, forming device chips, and then bonding the device surfaces together, A protective film formation process in which a protective film is formed on the metal portion exposed on the device on the substrate, A cutting process in which cutting water is supplied along the planned division lines of the substrate while the substrate is cut with a cutting blade, A grinding step in which the surface of the substrate opposite to the surface on which the device is formed is ground with a grinding wheel to thin it, A protective film removal step to remove the protective film, A bonding process in which the device surfaces of the device chips are bonded together, Equipped with, The protective film formation step is a method for manufacturing a semiconductor device in which a protective film is formed on the metal portion of the device by supplying a protective film forming solution containing a corrosion inhibitor.

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