Processing method of workpiece

Abstract

[Problem] To provide a processing method for a workpiece that can suppress residual burrs. [Solution] A processing method for a workpiece in which an electrode is embedded is processed, comprising: a holding step in which the front side of the workpiece is held by a chuck; a grinding step in which, after the holding step, a grinding wheel containing a grinding stone is rotated in a first direction, and the grinding stone is brought into contact with the back side of the workpiece held by the chuck, thereby grinding the workpiece and exposing the electrode on the back side of the workpiece; and an electrode processing step in which, after the grinding step, a grinding stone is brought into contact with the electrode exposed on the back side of the workpiece held by the chuck, while the grinding wheel is rotated in a second direction opposite to the first direction, thereby processing the electrode.

Description

Technical Field

[0001] This invention relates to a processing method for a workpiece in which an embedded electrode has been used for processing. Prior Technology

[0002] In the manufacturing process of electronic components, a wafer in which components are formed is used in multiple regions divided by multiple intersecting dicing lines (pre-defined dicing lines). By dicing this wafer along the dicing lines, multiple component chips, each containing a component, are obtained. These component chips are then assembled into various electronic devices such as mobile phones and personal computers.

[0003] Furthermore, in recent years, to achieve high integration of components, technology has been implemented to manufacture component chips (layered component chips) that incorporate multiple stacked components. For example, a layered component chip is manufactured by stacking multiple component chips and connecting them to each other using through-silicon vias (TSVs) that run through the component chips from top to bottom. Using TSVs shortens the wiring between components compared to methods such as wire bonding, thus enabling miniaturization of the layered component chip and increased processing speed.

[0004] In manufacturing a laminated device chip formed by connecting stacked components with silicon through-holes (STOV), a wafer with STOV is used (see Patent Document 1). For example, multiple wafers with STOV are stacked together, and the components contained in each wafer are connected to each other through STOVV, thereby forming a laminated wafer. By dicing this laminated wafer along dicing lines, multiple laminated device chips are obtained. [Known Technical Documents] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2001-53218 Summary of the Invention

[0006] [The problem that the invention aims to solve] When forming silicon through-holes in workpieces such as wafers, firstly, conductive material is filled into a groove formed on the front side of the workpiece to form a workpiece with embedded electrodes. Then, the back side of the workpiece is ground to expose the embedded electrodes on the back side of the workpiece, thereby forming a silicon through-hole that penetrates the workpiece in the thickness direction.

[0007] A grinding apparatus is used to grind a workpiece. The grinding apparatus includes a chuck table for holding the workpiece and a grinding unit for grinding the workpiece. The grinding unit is equipped with a grinding wheel containing multiple grinding stones. The workpiece is held by the chuck table, and while the chuck table and the grinding wheels are rotated, the grinding stones are brought into contact with the back side of the workpiece, thereby grinding the back side of the workpiece.

[0008] However, if the workpiece is ground until the embedded electrodes are exposed on the back side of the workpiece, the grinding stone will come into contact with the exposed electrodes on the back side of the workpiece during the final stage of the grinding process. At this time, the electrodes may sometimes be elongated by the high-speed rotating grinding stone, producing whisker-like burrs extending from the electrodes. These burrs can sometimes cause defects such as shape deformation of silicon vias on the back side of the workpiece and short circuits between adjacent electrodes, thus reducing the quality of the component wafer.

[0009] The present invention was made in view of the aforementioned problems, and its object is to provide a processing method for a workpiece that can suppress residual burrs.

[0010] [Technical means to solve the problem] According to one aspect of the present invention, a method for processing a workpiece is provided, which processes a workpiece with an embedded electrode, and includes: a holding step in which the front side of the workpiece is held by a chuck table; a grinding step in which, after the holding step, while a grinding wheel containing a grinding stone is rotated in a first direction, the grinding stone is brought into contact with the back side of the workpiece held by the chuck table, thereby grinding the workpiece and exposing the electrode on the back side of the workpiece; and an electrode processing step in which, after the grinding step, while the grinding wheel is rotated in a second direction opposite to the first direction, the grinding stone is brought into contact with the electrode exposed on the back side of the workpiece held by the chuck table, thereby processing the electrode.

[0011] [Invention Benefits] In one aspect of the processing method for the workpiece of the present invention, after the electrode is exposed on the back side of the workpiece by grinding the workpiece with a grinding wheel rotating in a first direction, the electrode is processed by a grinding wheel rotating in a second direction opposite to the first direction. This reduces or removes burrs extending from the electrode, and suppresses burr residue after grinding. Simple Explanation of the Diagram

[0012] Figure 1(A) is a perspective view of the workpiece, Figure 1(B) is a cross-sectional view of the workpiece, and Figure 1(C) is a perspective view of the component. Figure 2 is a perspective view of the grinding device. Figure 3 is a cross-sectional view of the chuck stage. Figure 4 is a flowchart illustrating the processing method for the workpiece. Figure 5 is a side view of a grinding apparatus that holds the workpiece in a chuck table. Figure 6(A) is a side view of a grinding device for grinding a workpiece, Figure 6(B) is a side view of a grinding device for removing a grinding stone from a workpiece, and Figure 6(C) is a side view of a grinding device for machining an electrode. Figure 7(A) is a top view of the workpiece during the grinding step, and Figure 7(B) is a top view of the electrode during the grinding step. Figure 8(A) is a top view of the workpiece in the electrode processing step, and Figure 8(B) is a top view of the electrode in the electrode processing step. Implementation

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. First, an example of the structure of a workpiece that can be processed by the processing method of this embodiment will be described. FIG1(A) is a perspective view of the workpiece 11, and FIG1(B) is a cross-sectional view of the workpiece 11.

[0014] For example, the workpiece 11 is a disk-shaped wafer made of semiconductor materials such as single-crystal silicon, and has a front side (first side) 11a and a back side (second side) 11b that are generally parallel to each other. The workpiece 11 is divided into multiple rectangular regions by multiple dicing lines (pre-defined dividing lines) 13 arranged in a grid pattern in an intersecting manner. Furthermore, on the multiple regions divided by the dicing lines 13 on the front side 11a of the workpiece 11, components such as IC (Integrated Circuit), LSI (Large Scale Integration), LED (Light Emitting Diode), and MEMS (Micro Electro Mechanical Systems) components are formed respectively.

[0015] However, there are no restrictions on the material, shape, structure, or size of the workpiece 11. For example, the workpiece 11 can also be a substrate (wafer) made of semiconductors other than silicon (GaAs, InP, GaN, SiC, etc.), glass, ceramics, resin, metal, etc. Furthermore, there are no restrictions on the type, quantity, shape, structure, size, or arrangement of the components 15.

[0016] Figure 1(C) is a perspective view of element 15. For example, element 15 includes a plurality of electrodes, which are exposed on the front side of element 15 and connected to other wiring, electrodes, components, etc. In addition, bumps or the like can also be formed on the front side of electrode 17 to connect to the electrode.

[0017] Furthermore, multiple electrodes (through-silicon vias, silicon through-holes) 19 are embedded within the multiple regions divided by the cutting groove 13 of the workpiece 11. The electrodes 19 are formed into a columnar shape along the thickness direction of the workpiece 11 and are connected to the electrodes 17 of the element 15, etc. There are no restrictions on the material of the electrodes 19; for example, conductive materials such as copper, tungsten, and aluminum can be used.

[0018] Electrodes 19 are formed from element 15 toward the back surface 11b of workpiece 11, and the length (height) of electrode 19 is less than the thickness of workpiece 11. Therefore, electrode 19 is not exposed on the back surface 11b of workpiece 11, but is embedded inside workpiece 11. Furthermore, an insulating film (not shown) such as a silicon oxide film is provided between workpiece 11 and electrode 19 to insulate workpiece 11 from electrode 19.

[0019] For example, after forming an insulating film on the inner wall of a columnar groove formed on the front side 11a of the workpiece 11, a conductive material is filled into the groove. This forms a workpiece 11 with an embedded electrode 19. Then, an element 15 comprising a semiconductor element, electrode, wiring, insulating film, etc., is formed on the front side 11a of the workpiece 11, and the element 15 is connected to the electrode 19.

[0020] If the workpiece 11 is thinned by grinding the back side 11b, the lower end of the electrode 19 is exposed on the back side 11b of the workpiece 11. As a result, the electrode 19 becomes a silicon through-hole penetrating the workpiece 11 in the thickness direction, and thus becomes able to connect other wiring, electrodes, components, etc. In this way, a workpiece 11 with a silicon through-hole is formed.

[0021] The workpiece 11 is ground using a grinding apparatus. Figure 2 is a perspective view of the grinding apparatus 2. Furthermore, in Figure 2, the X-axis direction (first horizontal direction, front-back direction) and the Y-axis direction (second horizontal direction, left-right direction) are perpendicular to each other. Also, the Z-axis direction (machining feed direction, vertical direction, height direction, up-down direction) is perpendicular to both the X-axis and Y-axis directions. The grinding apparatus 2 includes: a chuck table (holding table) 4 that holds the workpiece 11; and a grinding unit 10 that grinds the workpiece 11.

[0022] The chuck stage 4 includes a cylindrical frame (body) 6, which is made of metals such as SUS (stainless steel), glass, ceramics, resin, etc. A cylindrical recess 6b is provided at the center of the upper surface 6a of the frame 6. A disc-shaped retaining member 8 is embedded in the recess 6b, and the disc-shaped retaining member 8 is made of a porous material such as porous ceramic. The retaining member 8 includes a hole (flow path) connecting the upper surface to the lower surface of the retaining member 8. The upper surface of the retaining member 8 forms a circular suction surface 8a, which attracts the workpiece 11 when it is held by the chuck stage 4.

[0023] Furthermore, the depth of the recess 6a and the thickness of the retaining member 8 are set to be approximately the same, and the upper surface 6a of the frame 6 and the suction surface 8a of the retaining member 8 are arranged on approximately the same plane. Then, the retaining surface 4a of the chuck table 4 is formed by the upper surface 6a of the frame 6 and the suction surface 8a of the retaining member 8. The retaining surface 4a (suction surface 8a) is connected to a suction source (not shown) such as an injector through the holes contained in the retaining member 8, the flow path 6c formed inside the frame 6 (see Figure 3), a valve (not shown), etc.

[0024] A moving unit (not shown) is connected to the chuck table 4, which moves the chuck table 4 in the horizontal direction (XY plane direction). For example, a ball screw type moving mechanism or a rotary table can be used as the moving unit. Furthermore, a rotary drive source such as a motor (not shown) is connected to the chuck table 4, which rotates the chuck table 4 about a rotation axis set in a direction perpendicular to the holding surface 4a.

[0025] Figure 3 is a cross-sectional view of the chuck stage 4. The holding surface 4a of the chuck stage 4 is formed into a cone shape with its center as the apex, and is slightly inclined relative to the radial direction of the holding surface 4a. Then, the chuck stage 4 is configured in a slightly inclined state such that the holding region 4b, which corresponds to a part of the holding surface 4a and extends from the center of the holding surface 4a to the outer periphery, is arranged parallel to the horizontal plane. Furthermore, the rotation axis of the chuck stage 4 is set along a direction perpendicular to the radial direction of the holding surface 4a, and is slightly inclined relative to the vertical direction.

[0026] Furthermore, although the inclination of the retaining surface 4a is exaggerated in Figure 3 for ease of explanation, the actual inclination of the retaining surface 4a is small. For example, in the case where the diameter of the retaining surface 4a is about 290 mm or more and about 310 mm or less, the difference between the height of the center of the retaining surface 4a and the height of the outer periphery of the retaining surface 4a (equivalent to the height of the cone) is set to about 20 μm or more and about 40 μm or less.

[0027] As shown in Figure 2, a grinding unit 10 is arranged above the chuck table 4. The grinding unit 10 has a cylindrical spindle 12 arranged along the Z-axis. A disc-shaped mounting member 14 made of metal or the like is fixed to the front end (lower end) of the spindle 12. Furthermore, a rotary drive source (not shown) such as a motor is connected to the base end (upper end) of the spindle 12, which causes the spindle 12 to rotate in both directions.

[0028] An annular grinding wheel 16 for grinding the workpiece 11 is mounted on the lower surface of the mounting member 14. The grinding wheel 16 is a machining tool that can be attached to and detached from the mounting member 14, and is fixed to the mounting member 14 by means of fixing tools such as bolts.

[0029] The grinding wheel 16 includes an annular wheel base 18, which is made of metal (aluminum, stainless steel, etc.), resin, etc., and is formed to have approximately the same diameter as the mounting member 14. The upper surface of the wheel base 18 is fixed to the lower surface of the mounting member 14. Furthermore, a plurality of grinding stones 20 are fixed to the lower surface of the wheel base 18.

[0030] The grinding stone 20 is formed by fixing abrasive grains made of diamond, cBN (cubic boron nitride), etc., with a bonding material such as a metal bond, resin bond, or ceramic bond. For example, multiple grinding stones 20 are formed into cuboids and arranged in a ring at approximately equal intervals along the outer periphery of the wheel base 18. However, there are no restrictions on the material, shape, structure, or size of the grinding stones 20. Furthermore, the number and arrangement of the grinding stones 20 can be arbitrarily set.

[0031] The grinding unit 10 is connected to a ball screw type moving mechanism (not shown), which moves (lifts and lowers) the grinding unit 10 along the Z-axis direction. Furthermore, the grinding wheel 16 rotates about a rotation axis that is substantially parallel to the Z-axis direction by means of power transmitted from a rotation drive source (not shown) connected to the base end of the spindle 12 through the spindle 12 and the mounting member 14.

[0032] If the grinding wheel 16 is rotated, the plurality of grinding stones 20 move along a circular rotating track (movement path) that is approximately parallel to the horizontal plane (XY plane). With the grinding wheel 16 rotated, the grinding stones 20 contact the workpiece 11 held by the chuck table 4, thereby grinding the workpiece 11.

[0033] Furthermore, a slurry supply path (not shown) is provided inside or near the grinding unit 10, which supplies a liquid such as pure water (slurry). When the workpiece 11 is ground by the grinding unit 10, the slurry is supplied to the workpiece 11 and the grinding stone 20. This cools the workpiece 11 and the grinding stone 20, and washes away the chips (shavings) generated during the grinding process.

[0034] Next, a specific example of the processing method for the workpiece 11 using the grinding apparatus 2 will be described. Figure 4 is a flowchart showing the processing method for the workpiece. The processing method for the workpiece in this embodiment includes: a holding step S1, a grinding step S2, and an electrode processing step S3. By sequentially performing the holding step S1, the grinding step S2, and the electrode processing step S3, the electrode 19 (see Figures 1(B) and 1(C)) is exposed on the back surface 11b side of the workpiece 11, and the burrs formed on the electrode 19 are removed.

[0035] First, the workpiece 11 is held on the front 11a side by the chuck table 4 (holding step S1). Figure 5 is a side view of the grinding apparatus 2 holding the workpiece 11 by the chuck table 4.

[0036] The workpiece 11 is positioned on the chuck stage 4 with its front side 11a facing the holding surface 4a and its back side 11b exposed above. At this time, the workpiece 11 is positioned such that its center position overlaps with the center position of the holding surface 4a, and thus covers the entire suction surface 8a (see Figure 2). In this state, if the suction force (negative pressure) of the suction source is applied to the holding surface 4a, the workpiece 11 will be attracted and held by the chuck stage 4.

[0037] Furthermore, strictly speaking, as mentioned above, the holding surface 4a of the chuck stage 4 is formed into a conical shape (see Figure 3). Therefore, if the workpiece 11 is held by the chuck stage 4, the workpiece 11 is held in a state of slight deformation along the holding surface 4a.

[0038] Furthermore, a protective sheet can also be attached to the front side 11a of the workpiece 11 to protect the workpiece 11. In this way, the element 15 formed on the front side 11a of the workpiece 11 (see Figures 1(A) to 1(C)) is covered and protected by the protective sheet.

[0039] For example, an adhesive film can be used as a protective sheet, the film comprising: a thin-film substrate formed into a circle; and an adhesive layer (paste layer) disposed on the substrate. The substrate is made of resins such as polyolefin, polyvinyl chloride, and polyethylene terephthalate. Furthermore, the adhesive layer is made of epoxy, acrylic, or rubber-based adhesives. The workpiece 11 is then held by the holding surface 4a of the chuck stage 4 through the protective sheet.

[0040] Next, with the grinding wheel 16 rotated in the first direction, the grinding stone 20 is brought into contact with the back surface 11b side of the workpiece 11 held by the chuck table 4, and the workpiece 11 is ground, exposing the electrode 19 (see Figures 1(B) and 1(C)) on the back surface 11b side of the workpiece 11 (grinding step S2). Figure 6(A) is a side view of the grinding apparatus 2 for grinding the workpiece 11.

[0041] In the grinding step S2, firstly, the positional relationship between the chuck table 4 and the grinding wheel 16 is adjusted. Specifically, the chuck table 4 is positioned below the grinding unit 10 such that the center of the workpiece 11 overlaps with the rotational track of the grinding stone 20. Then, the chuck table 4 and the grinding wheel 16 are rotated in predetermined directions at predetermined speeds.

[0042] For example, in the grinding step S2, the chuck table 4 and the grinding wheel 16 are rotated clockwise when viewed from above. This causes the grinding wheel 16 to rotate in the first direction (as indicated by arrow A). Furthermore, the rotational speed of the chuck table 4 is, for example, set to 60 rpm or more and 300 rpm or less, and the rotational speed of the grinding wheel 16 is, for example, set to 3000 rpm or more and 6000 rpm or less.

[0043] Next, with the chuck table 4 and grinding wheel 16 already rotated, the grinding unit 10 is lowered along the Z-axis, bringing the workpiece 11 and the grinding wheel 16 closer together. The descent speed of the grinding wheel 16 at this time, which is also the relative movement speed of the chuck table 4 (workpiece 11) and the grinding wheel 16 in the Z-axis direction, is equivalent to the machining feed rate (grinding feed rate). The machining feed rate is, for example, set to 0.1 μm / s or more and 1 μm / s or less. However, the machining feed rate can be appropriately set according to the type and material of the workpiece 11, the material of the grinding stone 20, and the grinding amount of the workpiece 11 (the difference in thickness of the workpiece 11 before and after grinding).

[0044] If the grinding wheel 16 is lowered, the rotating grinding stone 20 contacts the back side 11b of the workpiece 11 held by the chuck table 4. In this way, the back side 11b of the workpiece 11 is ground and removed, thereby thinning the workpiece 11.

[0045] Figure 7(A) is a top view showing the workpiece 11 in grinding step S2. In grinding step S2, the grinding stone 20 contacts the portion of the workpiece 11 supported by the holding area 4b of the chuck table 4 (see Figure 3) or its vicinity, and grinds the workpiece 11 in an arc shape along a first direction (in the direction indicated by arrow A, from the outer periphery of the workpiece 11 toward the center). Then, by rotating the chuck table 4, the entire back side 11b of the workpiece 11 is ground by the grinding stone 20.

[0046] If the workpiece 11 is ground to a predetermined thickness, the electrode 19 embedded in the workpiece 11 will be exposed on the back side 11b of the workpiece 11. In this way, the electrode 19 becomes a silicon via penetrating the workpiece 11 in the thickness direction, and becomes able to connect the electrode 19 to other wiring, electrodes, components, etc.

[0047] Figure 7(B) is a top view showing the electrode 19 in the grinding step S2. If the workpiece 11 is ground until the electrode 19 is exposed on the back side 11b of the workpiece 11, the grinding stone 20 will come into contact with the electrode 19 in the final stage of the grinding step S2. At this time, the electrode 19 may be elongated by the grinding stone 20 rotating at high speed, and a beard-like burr 19a may form along the rotation direction of the grinding stone 20 (in the direction indicated by arrow A in Figure 7(A)).

[0048] The burr 19a is formed to extend from the electrode 19 and protrude from the outer periphery of the electrode 19. This burr 19a is a cause of defects such as shape deformation of the electrode 19 on the back side 11b of the workpiece 11 and short circuits between adjacent electrodes 19. Therefore, in this embodiment, the burr 19a is reduced or removed by machining the electrode 19 with the grinding wheel 16 after the grinding step S2. This suppresses the residue of the burr 19a in the workpiece 11.

[0049] Specifically, firstly, after the grinding step S2, the grinding unit 10 is raised along the Z-axis direction, thereby separating the workpiece 11 from the grinding stone 20. Figure 6(B) is a side view of the grinding device 2 that separates the grinding stone 20 from the workpiece 11.

[0050] Furthermore, it is preferable to maintain the rotation of the chuck stage 4 even when the workpiece 11 is not in contact with the grinding stone 20. This reduces the time required to rotate the chuck stage 4 at a predetermined speed in the subsequent electrode machining step S3.

[0051] Next, with the grinding wheel 16 rotated in the second direction, the grinding stone 20 is brought into contact with the electrode 19 exposed on the back side 11b of the workpiece 11 held by the chuck table 4, thereby machining the electrode 19 (electrode machining step S3). Figure 6(C) is a side view of the grinding apparatus 2 for machining the electrode 19.

[0052] In electrode processing step S3, firstly, the spindle 12 is rotated in the opposite direction to the rotation direction of the spindle 12 in grinding step S2. Consequently, the grinding wheel 16 rotates in a second direction opposite to the first direction (as indicated by arrow B). For example, if the grinding wheel 16 rotates clockwise in view from above in grinding step S2, it rotates counterclockwise in view from above in electrode processing step S3. Furthermore, the rotational speed of the chuck table 4 is set, for example, to be between 60 rpm and 300 rpm, and the rotational speed of the grinding wheel 16 is set, for example, to be between 3000 rpm and 6000 rpm.

[0053] Next, with the chuck table 4 and grinding wheel 16 already rotated, the grinding unit 10 is lowered along the Z-axis, bringing the workpiece 11 and the grinding wheel 16 closer together. Thereby, the rotating grinding stone 20 contacts the electrode 19 exposed on the back side 11b of the workpiece 11 held by the chuck table 4, and the electrode 19 and the back side 11b of the workpiece 11 are ground together.

[0054] Furthermore, if the workpiece 11 is separated from the grinding stone 20 before the grinding step S2 (see Figure 6(B)) as described above, then there will be no friction between the workpiece 11 and the grinding stone 20 before the electrode processing step S3 is performed, and both the workpiece 11 and the grinding stone 20 will cool down. This makes it less likely that processing defects such as burns to the workpiece 11 will occur during the electrode processing step S3. Moreover, during the electrode processing step S3, the grinding stone 20 re-enters contact with the workpiece 11 from its previous state. This promotes wear on the lower surface of the grinding stone 20, thus adjusting its state.

[0055] Figure 8(A) is a top view showing the workpiece 11 in electrode processing step S3. In electrode processing step S3, the grinding stone 20 contacts the part of the workpiece 11 that is supported by the holding area 4b of the chuck table 4 (see Figure 3) or the area nearby, and grinds the workpiece 11 in an arc shape along the second direction (in the direction indicated by arrow B, from the center of the workpiece 11 toward the outer periphery).

[0056] Furthermore, the movement direction (second direction) of the grinding stone 20 relative to the workpiece 11 in electrode processing step S3 is opposite to the movement direction (first direction) of the grinding stone 20 relative to the workpiece 11 in grinding step S2. Therefore, the grinding stone 20 grinds the electrode 19 in the direction opposite to that in grinding step S2. Then, by rotating the chuck table 4, all the electrodes 19 exposed on the back side 11b of the workpiece 11 are processed by the grinding stone 20.

[0057] Figure 8(B) is a top view showing the electrode 19 in electrode processing step S3. When the grinding stone 20 rotating in the second direction contacts the electrode 19, the grinding stone 20 contacts the electrode 19 in a direction opposite to the extension direction of the burr 19a (from the front end side of the burr 19a towards the base end side). In this way, the burr 19a is smoothed in the opposite direction towards the center side of the electrode 19, thereby reducing or removing the burr 19a.

[0058] Furthermore, electrode processing step S3 is a step for reducing or removing burrs 19a, and its direct purpose is not to thin the workpiece 11. Therefore, the grinding conditions in electrode processing step S3 can be freely set within a range that can reduce or remove burrs 19a.

[0059] Specifically, the amount of grinding of the workpiece 11 in electrode processing step S3 can be less than the amount of grinding of the workpiece 11 in grinding step S2. This suppresses over-grinding of the workpiece 11 or the generation of new burrs. For example, the amount of grinding of the workpiece 11 in electrode processing step S3 can be set to 10 μm or less, preferably 5 μm or less.

[0060] Furthermore, the machining feed rate (the descent speed of the grinding wheel 16) in electrode machining step S3 can be slower than the machining feed rate in grinding step S2. This reduces the load applied to the grinding stone 20 in electrode machining step S3, making it easier to remove burrs 19a. For example, the machining feed rate in electrode machining step S3 can be set to 1 μm / s or less, preferably 0.5 μm / s or less.

[0061] The machining of the workpiece 11 performed by the aforementioned grinding apparatus 2 is controlled by a control unit (not shown) connected to the grinding apparatus 2. For example, the control unit is configured as a computer and includes: an arithmetic unit that performs calculations required to operate the grinding apparatus 2; and a memory unit that stores various information (data, programs, etc.) used to operate the grinding apparatus 2. The arithmetic unit includes a processor such as a CPU (Central Processing Unit). Furthermore, the memory unit includes memory such as ROM (Read Only Memory) and RAM (Random Access Memory).

[0062] The control unit stores a program that describes a series of actions required to sequentially perform the holding step S1, the grinding step S2, and the electrode processing step S3 of the grinding apparatus 2. Then, when processing the workpiece 11, the control unit reads the program from the memory and executes it, sequentially outputting control signals to each component of the grinding apparatus 2. This controls the operation of the grinding apparatus 2 and automatically performs the holding step S1, the grinding step S2, and the electrode processing step S3.

[0063] As described above, in the workpiece processing method of this embodiment, after the workpiece 11 is ground by a grinding wheel 16 rotating in a first direction to expose the electrode 19 on the back surface 11b side of the workpiece 11, the electrode 19 is processed by a grinding wheel 16 rotating in a second direction opposite to the first direction. This reduces or removes burrs 19a extending from the electrode 19, thereby suppressing the presence of burrs 19a after grinding.

[0064] Furthermore, the structure and method of the above-described embodiments can be appropriately modified and implemented without departing from the purpose of the present invention.

[0065] 11: Workpiece 11a: Front (First Side) 11b: Reverse side (second side) 13: Cutting track (pre-defined dividing line) 15: Components 17: Electrode 19: Electrode (through-silicon via, silicon through-hole) 19a: Rough edges 2:Grinding device 4: Chuck stage (holding stage) 4a: Maintain surface 4b: Maintain the area 6: Frame (body part) 6a: Upper surface 6b: concave part 6c:Flow path 8: Retaining components 8a: Attraction surface 10: Grinding Unit 12: Spindle 14: Installation components 16: Grinding wheel 18: Wheel base platform 20: Grinding stone

Claims

1. A method for processing a workpiece, comprising processing a workpiece with an embedded electrode, characterized in that it includes: a holding step in which the front side of the workpiece is held by a chuck; a grinding step in which, after the holding step, while a grinding wheel containing a grinding stone is rotated in a first direction, the grinding stone is brought into contact with the back side of the workpiece held by the chuck, thereby grinding the workpiece to expose the electrode on the back side of the workpiece; and an electrode processing step in which, after the grinding step, while the grinding wheel is rotated in a second direction opposite to the first direction, the grinding stone is brought into contact with the electrode exposed on the back side of the workpiece held by the chuck, thereby processing the electrode, wherein the amount of grinding of the workpiece in the electrode processing step is less than the amount of grinding of the workpiece in the grinding step.

2. The processing method for the workpiece as described in claim 1, wherein, In this electrode processing step, the grinding depth of the workpiece is less than 10 μm.

3. A method for processing a workpiece, comprising processing a workpiece with an embedded electrode, characterized in that it includes: a holding step in which the front side of the workpiece is held by a chuck; a grinding step in which, after the holding step, while a grinding wheel containing a grinding stone is rotated in a first direction, the grinding stone is brought into contact with the back side of the workpiece held by the chuck, thereby grinding the workpiece to expose the electrode on the back side of the workpiece; and an electrode processing step in which, after the grinding step, while the grinding wheel is rotated in a second direction opposite to the first direction, the grinding stone is brought into contact with the electrode exposed on the back side of the workpiece held by the chuck, thereby processing the electrode, wherein the processing feed rate in the electrode processing step is slower than the processing feed rate in the grinding step.

4. The processing method for the workpiece as described in claim 3, wherein, The machining feed rate in this electrode machining step is less than 1 μm / s.

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