Grinding Equipment

Abstract

To provide a grinding device capable of efficiently carrying out maintenance work and discharging grinding water to a fixed place to efficiently cool a wafer and a grindstone.SOLUTION: A grinding device 1 comprises: a chuck 11 that absorbs and holds a wafer W; a spindle 21 having a grindstone 20 for grinding the wafer W fitted to the lower end and provided above the chuck 11 to be liftable; a jacket 23 that stores the spindle 21 and that is provided to be liftable; and a grinding water supply mechanism 50 having a plurality of nozzles 51 through which the grinding water is discharged toward at least one of the wafer W and the grindstone 20 and which is provided so as to be liftable integrally with the jacket 23. The nozzles 51 are fixed in grinding water discharging direction so as to discharge the grinding water to a fixed position.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a grinding device that grinds a wafer with a grinding wheel. [Background technology]

[0002] 2. Description of the Related Art In the field of semiconductor manufacturing, back grinding is performed to grind the back surface of a semiconductor wafer such as a silicon wafer (hereinafter referred to as a "wafer") to form a thin film.

[0003] Patent document 1 discloses a grinding processing apparatus 10 that grinds the upper surface of a wafer W held by suction on a chuck table 11 with a grinding wheel 12 while grinding water (cooling water) is supplied between the grinding wheel 12 and the wafer W from a nozzle provided at the tip of a coolant supply mechanism 17.

[0004] The coolant supply mechanism 17 is installed on the side of a chamber that houses an arm-shaped sensor moving mechanism 18 carrying a non-contact type sensor 15, a contact type sensor, etc. The nozzle of the coolant supply mechanism 17 is connected to a flexible hose, and is configured so that the supply position of the grinding water can be changed as desired. The reference numerals are those in Patent Document 1. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-184604 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the grinding device 10 described in Patent Document 1, various devices are arranged in a narrow chamber, and therefore, during maintenance work, the flexible hose must be bent to move the nozzle away from the vicinity of the grinding wheel 12, which tends to make the maintenance work complicated. In addition, since the operator manually bends the flexible hose to adjust the nozzle position, there is a problem that the discharge position of the grinding water may not be constant.

[0007] Therefore, a technical problem arises that needs to be solved in order to enable maintenance work to be carried out efficiently and to eject grinding water to a specific location to efficiently cool the wafer and grinding wheel, and the present invention aims to solve this problem. [Means for solving the problem]

[0008] In order to achieve the above object, a grinding apparatus according to the present invention includes a chuck for suction-holding a wafer, a spindle having a grinding wheel for grinding the wafer attached to its lower end and arranged above the chuck and capable of being raised and lowered, a jacket for accommodating the spindle and arranged to be capable of being raised and lowered, and a grinding water supply mechanism having a plurality of nozzles arranged integrally with the jacket and capable of being raised and lowered, for discharging grinding water toward at least one of the wafer and the grinding wheel, wherein the direction in which the grinding water is discharged by the plurality of nozzles is fixed so that the grinding water is discharged to a fixed position. The plurality of nozzles includes at least one first nozzle disposed corresponding to a first position in the chuck, and at least one second nozzle disposed corresponding to a second position in the chuck closer to a processing line where the grindstone contacts the wafer than the first position, the first position corresponding to a down-cut processing line where the grindstone grinds the wafer from the center of the wafer toward the outer periphery, and the second position corresponding to an up-cut processing line where the grindstone grinds the wafer from the outer periphery of the wafer toward the center. do.

[0009] According to this configuration, the nozzle is configured to be able to move up and down integrally with the jacket, so that the nozzle does not interfere with the operator's working space during maintenance, and maintenance work can be carried out efficiently. In addition, since there is no need to change the direction of the nozzle every time maintenance is performed, grinding water can be discharged to a fixed location. Effect of the Invention

[0010] In the present invention, the nozzle is configured to be able to move up and down integrally with the jacket, so that the nozzle does not interfere with the operator's work space during maintenance, and maintenance work can be carried out efficiently. In addition, since there is no need to change the direction of the nozzle every time maintenance is performed, grinding water can be discharged to a fixed location. [Brief description of the drawings]

[0011] [Figure 1] 1 is a plan view of a grinding device according to an embodiment of the present invention, viewed from above; [Diagram 2] FIG. [Diagram 3] FIG. 3 is an enlarged perspective view of a main part of FIG. 2. [Figure 4] FIG. [Diagram 5] 3A and 3B are a plan view and a side view showing a schematic diagram of down-cutting. [Figure 6] 3A and 3B are a plan view and a side view, respectively, which show a schematic diagram of an upcut. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] An embodiment of the present invention will be described with reference to the drawings. In the following, when the number, numerical value, amount, range, etc. of components are mentioned, the number is not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited to a specific number in principle.

[0013] In addition, when referring to the shape or positional relationship of components, etc., this includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or considered to be clearly different in principle.

[0014] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional ratios of the components may not be the same as the actual ones. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0015] The grinding apparatus 1 grinds one surface (surface to be processed) of a wafer W into a flat surface. The grinding apparatus 1 is partitioned into one or more chambers C according to processes. By providing multiple chambers C, multiple wafers W can be processed continuously. FIG. 1 is a plan view showing the configuration inside the chamber C. FIG. 2 is a perspective view showing the grinding apparatus 1.

[0016] The grinding apparatus 1 includes an index table 10 and a chuck 11 that is disposed on the index table 10 and holds the other surface of the wafer W by suction.

[0017] The index table 10 is rotatable around a rotation axis 12, and a plurality of chucks 11 are provided concentrically around the rotation axis 12 at equal intervals.

[0018] The chuck 11 has an adsorbent (not shown) made of a porous material such as alumina embedded in its upper surface. The chuck 11 has a conduit (not shown) that runs through the inside and reaches the surface. The conduit is connected to a vacuum source, a compressed air source, or a water supply source via a rotary joint (not shown). When the vacuum source is activated, the wafer W placed on the chuck 11 is adsorbed and held by the chuck 11. When the compressed air source or the water supply source is activated, the adsorption between the wafer W and the chuck 11 is released.

[0019] The grinding device 1 also includes a grindstone 20, a spindle 21, and a spindle feed mechanism 22. For example, a cup-shaped grindstone is used as the grindstone 20. The grindstone 20 is attached to the lower end of the spindle 21. The spindle 21 is configured to be rotatable together with the grindstone 20.

[0020] The spindle feed mechanism 22 is configured to raise and lower the jacket 23, which houses the spindle 21, in the vertical direction (the up and down direction on the paper surface of FIG. 2). The spindle feed mechanism 22 includes two linear guides 25 that connect the jacket 23 and the column 24, and a known ball screw slider mechanism 26 that raises and lowers the jacket 23 in the vertical direction.

[0021] In the chamber C, a fixed thickness gauge 30 and a mobile thickness gauge 40 are provided.

[0022] The fixed thickness gauge 30 measures the wafer thickness at a fixed point at a predetermined radial position on the wafer W. The fixed thickness gauge 30 is equipped with a pair of sensor heads 31, 32. The sensor head 31 is disposed so as to be able to contact the upper surface of the wafer W, and measures the height of the lower end of the sensor head 31. The sensor head 32 is disposed outside the sensor head 31, and is provided so as to be able to contact the upper surface of the chuck 11, and measures the height of the lower end of the sensor head 32. The difference between the measured values ​​of the sensor heads 31, 32 is the thickness of the wafer W.

[0023] The mobile thickness measuring device 40 measures the thickness of the wafer W while moving in the radial direction above the wafer W. The mobile thickness measuring device 40 includes a sensor 41 and an arm 42 having the sensor 41 provided at the tip thereof.

[0024] The sensor 41 is a film thickness sensor that measures the thickness of the wafer W in a non-contact manner during grinding. The sensor 41 is preferably, for example, a spectral interference film thickness sensor. The spectral interference film thickness sensor is resistant to disturbances such as vibrations and can measure the thickness of the wafer W with high accuracy. In the following, an example will be described in which a spectral interference film thickness sensor is used as the sensor 41.

[0025] A sensor head (not shown) of the sensor 41 irradiates light toward the wafer W and receives reflected light resulting from interference between the light reflected on the upper and lower surfaces of the wafer W. The reflected light is split by a spectroscope, and a control device (described later) calculates the thickness of the wafer W based on the optical path difference between the light reflected on the upper surface of the wafer W and the light reflected on the lower surface of the wafer W.

[0026] The arm 42 is capable of swinging about a drive shaft 43 in the radial direction of the wafer W. The arm 42 is capable of swinging so that the sensor 41 can scan from the outer periphery of the wafer W to a position where the sensor 41 does not interfere with the grindstone 20.

[0027] The fixed thickness gauge 30 and the mobile thickness gauge 40 are provided on opposite sides of the spindle 21 with respect to an opening O through which an operator accesses the chamber C when performing maintenance work.

[0028] The grinding water supply mechanism 50 supplies grinding water (cooling water) between the grindstone 20 and the wafer W. The specific configuration of the grinding water supply mechanism 50 will be described later.

[0029] The operation of the grinding apparatus 1 is controlled by a control device (not shown). The control device controls each of the components constituting the grinding apparatus 1. The control device is, for example, a computer, and is composed of a CPU, a memory, and the like. The functions of the control device may be realized by control using software, or may be realized by operation using hardware.

[0030] Next, a specific configuration of the grinding water supply mechanism 50 will be described with reference to FIGS.

[0031] The grinding water supply mechanism 50 includes a nozzle 51 protruding from the lower end of the jacket 23. The nozzle 51 is provided with a discharge port 52 facing downward. The nozzle 51 is connected to a pipe 53 through which the grinding water passes, and supplies the grinding water between the wafer W and the grinding wheel 20. Four nozzles 51 are provided along the rotation direction D of the grinding wheel 20. The number of nozzles 51 is not limited to four, and may be three or less, or five or more. In Figs. 2 to 4, a part of the pipe 53 is omitted.

[0032] A valve 54 is installed in the piping 53 through which the grinding water passes, and is configured so that the grinding water can pass through either two nozzles 51 provided on one side of the rotational direction D (hereinafter collectively referred to as the "first nozzle group A") or two nozzles 51 provided on the other side of the rotational direction D (hereinafter collectively referred to as the "second nozzle group B").

[0033] The nozzle 51 is formed in a substantially L-shape when viewed from the side. The nozzle 51 is also configured to be rigid (i.e., unable to bend) in the direction of supplying the grinding water. This allows the nozzle 51 to supply the grinding water to substantially the same position. The base end side of the nozzle 51 is also connected to the inside of the jacket 23 via a link mechanism 55. This allows the nozzle 51 to rotate around the link mechanism as a fulcrum, and the direction of the discharge port 52 can be finely adjusted, so that the grinding wheel 20 and the wafer W can be efficiently cooled.

[0034] Next, the operation of the grinding device 1 will be described with reference to the drawings.

[0035] First, the index table 10 rotates, and the chuck 11 that suction-holds the wafer W is transported into the chamber C and positioned below the grinding wheel 20. Then, the spindle feed mechanism 22 is driven to move the grinding wheel 20 close to the wafer W.

[0036] Next, grinding water is discharged from the first nozzle group A or the second nozzle group B to supply the grinding water between the wafer W and the grindstone 20.

[0037] Whether the grinding water is discharged from the first nozzle group A or the second nozzle group B is set according to the grinding conditions. For example, as shown in Figures 5(a) and (b), in the case of so-called down-cutting in which the grindstone 20 grinds the wafer W from the center of the wafer W toward the outer periphery, the grinding water is discharged at a location (first position) away from the processing line where the grindstone 20 contacts the wafer W in the rotation direction of the wafer W, so that the grinding water discharged onto the wafer W is spread over the entire processing line as the wafer W rotates. Therefore, in the case of down-cutting, the grinding water is discharged from the first nozzle group A arranged at the first position.

[0038] 6(a) and (b), in the case of so-called up-cut, in which the grindstone 20 grinds the wafer W from the outer periphery toward the center of the wafer W, more frictional heat is generated in grinding than in down-cut, in which the wafer W and the grindstone 20 rotate in the same direction, so it is necessary to discharge the grinding water at a position (second location) closer to the processing line than the first location. Therefore, in the case of up-cut, the grinding water is discharged from the second nozzle group B arranged at the second location.

[0039] In this manner, the grinding water supply mechanism 50 can reduce the amount of grinding water used by discharging the grinding water from the nozzle 51 that can be efficiently cooled according to the grinding conditions.

[0040] Next, while rotating the chuck 11 and the grindstone 20, the grindstone 20 is pressed against the surface of the wafer W. The grinding conditions of the grinding device 1 are, for example, a rotation speed of the chuck 11 of 300 rpm, a grit size of the grindstone 20 of #6000, a rotation speed of the spindle 21 of 2000 rpm, and a feed speed of the spindle feed mechanism 22 of 0.4 μm / s.

[0041] The grinding device 1 grinds the wafer W until the measurement value of the fixed thickness gauge 30 reaches a desired thickness (e.g., 6 μm). When grinding of the wafer W is completed, the chuck 11 and the grindstone 20 stop, the grindstone 20 retreats upward, and then the index table 10 rotates to transport the ground wafer W to the next process (polishing, cleaning, etc.).

[0042] In this way, in the grinding device 1 according to this embodiment, the nozzle 51 is configured to be able to rise and fall integrally with the jacket 23, so that the nozzle 51 does not interfere with the operator's working space during maintenance, and maintenance work can be carried out efficiently. Also, since there is no need to change the direction of the nozzle 51 every time maintenance is performed, the grinding water can be discharged to a fixed location.

[0043] Furthermore, since the nozzle 51 is configured to be unbendable, the grinding water discharged from the nozzle 51 is stably supplied to a fixed location.

[0044] The present invention can be modified in various ways without departing from the spirit of the invention, and it goes without saying that the present invention also covers such modifications. [Explanation of symbols]

[0045] 1. Grinding device 10 Index table 11. Chuck 12 Rotation axis 20 Grindstone 21 Spindle 22 Spindle feed mechanism 23...Jacket 24 Column 25 ···Linear guide 26 Ball screw slider mechanism 30 Fixed thickness gauge 31, 32: Sensor head 40 Mobile thickness gauge 41 Sensor 42 Arm 43 Drive shaft 50 Grinding water supply mechanism 51 Nozzle 52...Discharge port 53 Piping 54 Valve 55 Link mechanism A: First nozzle group B: Second nozzle group C...Chamber O...Opening

Claims

1. a chuck for suction-holding the wafer; a spindle having a lower end attached with a grindstone for grinding the wafer, the spindle being disposed above the chuck and capable of ascending and descending; A jacket that houses the spindle and is arranged to be liftable and lowerable; a grinding water supply mechanism having a plurality of nozzles that are vertically movable and integral with the jacket and that discharge grinding water toward at least one of the wafer and the grindstone; Equipped with The plurality of nozzles are fixed in the direction in which the grinding water is discharged so as to discharge the grinding water to a fixed position, The plurality of nozzles includes at least one first nozzle disposed corresponding to a first position in the chuck, and at least one second nozzle disposed corresponding to a second position in the chuck closer to a processing line where the grinding wheel contacts the wafer than the first position; the first position corresponds to a down-cut processing line in which the grindstone grinds the wafer from the center to the outer periphery of the wafer, A grinding apparatus, characterized in that the second position corresponds to an up-cut processing line in which the grinding wheel grinds the wafer from the outer periphery toward the center of the wafer.

2. 2. The grinding apparatus according to claim 1, wherein the nozzles are provided at a lower end outside the jacket.

3. The grinding apparatus according to claim 1 or 2, characterized in that the grinding water supply mechanism is configured to be able to switch among the plurality of nozzles through which the grinding water passes, depending on the grinding conditions under which the grinding wheel grinds the wafer.

Images