Chuck table

Abstract

To provide a chuck table applicable to a substrate processing device for flattening a non-circular shaped substrate to a desired thickness.SOLUTION: A chuck table 21 rotatably includes an adsorbent 23 that can adsorptively hold a non-circular shaped substrate W and a dense body 24 including a first area that is a space for filling the adsorbent 23 and a second area arranged in a circumference of the first area. The second area of the dense body 24 is provided with a notch section 26 having a contact area with a grindstone 31 expanding and contracting with every rotation angle of the dense body 24 when a surface of the dense body 24 is ground by the grindstone 31 and in accordance with every changes of rotation angles of the dense body 24 in a predicted contact area where the substrate W contacts with the grindstone 31 when the substrate W is machined by the grindstone 31.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a chuck table applicable to a substrate processing apparatus for planar processing of a non-circular substrate.

Background Art

[0002] In the field of semiconductor manufacturing, a substrate processing apparatus for planar processing of a semiconductor substrate such as a silicon wafer (hereinafter referred to as "substrate") to be thin and flat is known.

[0003] Patent Document 1 discloses a grinding apparatus that brings a rotating grindstone into contact with the upper surface of a rectangular workpiece held on a chuck table and grinds the rectangular workpiece to a predetermined thickness.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when grinding is performed by bringing the grindstone into contact with the rectangular workpiece held on the chuck table in parallel, the contact area between the grindstone and the rectangular workpiece at each predetermined rotation of the chuck table is not constant. In a region where the contact area is relatively large, the grinding amount of the rectangular workpiece is small, and in a region where the contact area is relatively small, the grinding amount of the rectangular workpiece tends to be large. That is, there is a problem that the thickness of the rectangular workpiece varies depending on the size of the contact area between the grindstone and the rectangular workpiece during processing, and the rectangular workpiece cannot be finished to a desired thickness.

[0006] Therefore, a technical problem to be solved arises in order to planar process a non-circular substrate to a desired thickness, and an object of the present invention is to solve this problem.

Means for Solving the Problems

[0007] In order to achieve the above object, the chuck table according to the present invention rotatably includes an adsorbent capable of adsorbing and holding a non-circular substrate, and a dense body including a first region that is a space for embedding the adsorbent and a second region disposed on the outer periphery of the first region. When the surface of the dense body is ground with a grindstone, a notch portion is formed in the second region such that the contact area with the grindstone expands and contracts for each rotation angle of the dense body in accordance with a change for each rotation angle of the dense body in a predicted contact area where the substrate comes into contact with the grindstone when the substrate is processed with the grindstone.

Advantages of the Invention

[0008] In the present invention, since the second region of the dense body is formed such that the grinding amount of self-grinding in which the grindstone grinds the surface of the dense body increases or decreases according to the rotation angle of the dense body so as to cancel out the thickness variation in which the grinding amount of the non-circular substrate locally varies, it is possible to reduce the thickness variation of the substrate after processing due to the shape of the substrate.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] Embodiments of the present invention will be described with reference to the drawings. In the following, when referring to the number of components, numerical values, amounts, ranges, etc., unless otherwise specifically stated and unless it is clearly limited to a specific number in principle, it is not limited to that specific number, and it may be more or less than the specific number.

[0011] In addition, when referring to the shape, positional relationship, etc. of components, etc., unless otherwise specifically stated or considered not to be so in principle, it includes those that are substantially approximate or similar to the shape, etc.

[0012] In addition, the drawings may be exaggerated, such as by enlarging characteristic parts for easy understanding of the features, and the dimensional ratios of the components are not necessarily the same as the actual ones.

[0013] Figure 1 is a front view showing the basic configuration of the substrate processing apparatus 1. The substrate processing apparatus 1 performs grinding on a wafer. The substrate processing apparatus 1 includes a holding means 2 and a processing means 3.

[0014] The holding means 2 includes a chuck table 21 and a chuck spindle 22.

[0015] The chuck table 21 includes an adsorbent 23 made of a porous material such as alumina on the upper surface and a dense body 24 embedded in the substantially center of the adsorbent 23. The chuck table 21 includes a pipeline (not shown) that extends from the inside to the surface. The pipeline 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 substrate W placed on the adsorbent 23 is adsorbed and held by the adsorbent 23. Also, when the compressed air source or the water supply source is activated, the adsorption between the substrate W and the adsorbent 23 is released.

[0016] The adsorbent 23 is formed in a shape corresponding to the substrate W when viewed from a plane. Also, the dense body 24 is formed in a substantially circular shape with a part of its outer periphery cut out when viewed from a plane, but the shape of the dense body 24 is not limited to this. The detailed shape of the dense body 24 will be described later.

[0017] The chuck spindle 22 is configured to rotationally drive the chuck table 21 around the rotation axis 2a. The drive source of the chuck spindle 22 may be, for example, a servo motor or the like.

[0018] The holding means 2 further includes a rotation angle detection unit 25. The rotation angle detection unit 25 detects the rotation angle of the chuck table 21, and sends a detection signal to a control device 4 (to be described later) every time the chuck table 21 rotates by a predetermined angle. For example, when the chuck spindle 22 is rotationally driven by a servo motor, since the rotation angle of the chuck table 21 corresponds to the rotation angle of the servo motor, the rotation angle detection unit 25 can detect the rotation angle of the chuck table 21 by reading the rotation angle of the servo motor.

[0019] The processing means 3 includes a grindstone 31, a grindstone spindle 32, and a feed mechanism 33.

[0020] The grindstone 31 is, for example, a cup-shaped grindstone, and is attached to the lower end of the grindstone spindle 32.

[0021] The grindstone spindle 32 is rotatable about the rotation axis 3a, and the grindstone 31 and the grindstone spindle 32 are configured to rotate integrally.

[0022] The feed mechanism 33 moves the grindstone spindle 32 up and down in the vertical direction. The feed mechanism 33 has a known configuration, and is composed of, for example, a plurality of linear guides that guide the moving direction of the grindstone spindle 32 and a ball screw slider mechanism that moves the grindstone spindle 32 up and down. The feed mechanism 33 is interposed between the grindstone spindle 32 and the column 34.

[0023] The operation of the substrate processing apparatus 1 is controlled by a control device 4. The control device 4 controls each component that constitutes the substrate processing apparatus 1. The control device 4 is composed of, for example, a CPU, a memory, etc. Note that the functions of the control device 4 may be realized by controlling using software, or may be realized by operating using hardware.

[0024] Next, the self-grinding of the substrate processing apparatus 1 will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing the state of self-grinding.

[0025] Self-grinding refers to the process of approaching the grinding wheel 31 to the chuck table 21 by the infeed mechanism 33 and grinding the holding surface 21a of the chuck table 21 with the grinding wheel 31, as shown in Fig. 2. Self-grinding is appropriately performed to maintain the holding surface 21a of the chuck table 21 in a desired shape, and it is generally performed when replacing the chuck table 21 or the like.

[0026] In the substrate processing apparatus 1, the grinding amount during self-grinding is locally increased or decreased within the holding surface 21a. This is because when the processing surface of the grinding wheel 31 is brought into parallel contact with the processed surface of the non-circular substrate W to perform planar processing on the substrate W, the processing amount (grinding amount) of the substrate W is not stable within the surface.

[0027] The reason will be described below with reference to Figs. 3 and 4. Fig. 3 is a plan view comparing the predicted contact areas between the substrate W and the grinding wheel 31 at two points within the substrate W. Fig. 4 is a plan view showing the chuck table 21. Hereinafter, a substrate W having a square shape in plan view will be described as an example, but the shape of the substrate W is not limited thereto.

[0028] As shown in Fig. 3, when comparing the predicted contact area S1 (rotation angle of the chuck table 21 = Θ) between the substrate W and the grinding wheel 31, where the processing surface of the grinding wheel 31 is set to pass through the corner of the substrate W and the rotation center O of the chuck table 21, and the predicted contact area S2 (rotation angle of the chuck table 21 = Θ - 45 degrees) between the substrate W and the grinding wheel 31, where the processing surface of the grinding wheel 31 is set to pass through the center of the side of the substrate W and the rotation center O, it can be seen that the predicted contact area S1 is approximately twice as wide as the predicted contact area S2.

[0029] When the grinding wheel 31 is uniformly brought into contact with the entire surface of the substrate W, as the predicted contact area between the substrate W and the grinding wheel 31 increases, the grinding amount of the substrate W decreases, and the processed substrate W becomes thicker. Therefore, when comparing the predicted contact areas S1 and S2 shown in Fig. 3, it is predicted that the processed substrate W will be locally thicker in the case of the predicted contact area S1.

[0030] Therefore, as shown in FIG. 4, the compact body 24 is formed in a substantially disk shape with a part of its outer periphery cut out, and is configured such that the contact area with the grindstone 31 changes appropriately along the rotation direction of the chuck table 21.

[0031] Specifically, a notch 26 is provided on the outer periphery of the compact body 24 such that the contact areas of the chuck table 21 and the grindstone 31 are inversely proportional to the predicted contact areas of the substrate W and the grindstone 31 when the substrate W is surface-machined with the grindstone 31.

[0032] In other words, within a predetermined rotation angle of the chuck table 21, when the predicted contact area of the substrate W and the grindstone 31 is larger than the predicted contact area (reference area) of the substrate W and the grindstone 31 serving as a reference, the area of the notch 26 is set such that the contact areas of the chuck table 21 and the grindstone 31 within this rotation angle become smaller. Note that the interval of the rotation angle of the chuck table 21 for calculating the predicted contact area can be arbitrarily changed.

[0033] Also, at a predetermined rotation angle of the chuck table 21, when the predicted contact area of the substrate W and the grindstone 31 is smaller than the reference area, the area of the notch 26 is set such that the contact areas of the chuck table 21 and the grindstone 31 within this rotation angle become larger.

[0034] In this way, the contact areas of the chuck table 21 and the grindstone 31 are expanded and contracted in inverse proportion to the size of the predicted contact area of the substrate W and the grindstone 31 with respect to the reference area.

[0035] FIG. 4 shows the shape of the compact body 24 when the predicted contact area S2 shown in FIG. 3 is set as the reference area. That is, as the chuck table 21 rotates from (Θ - 45 degrees) to Θ, the predicted contact area of the substrate W and the grindstone 31 expands, and the area of the notch 26 also gradually expands. As a result, the contact areas of the chuck table 21 and the grindstone 31 during self-grinding gradually become smaller in inverse proportion to the increase in the predicted contact area of the substrate W and the grindstone 31.

[0036] In this way, when the substrate processing apparatus 1 according to the present embodiment processes the substrate W with the grindstone 31, the compact 24 is formed such that the grinding amount of the self-grinding in which the grindstone 31 grinds the holding surface 21a increases or decreases for each predetermined rotation angle of the chuck table 21 so as to cancel out the thickness variation of the substrate W caused by the change in the predicted contact area between the substrate W and the grindstone 31 for each predetermined rotation angle of the chuck table 21. Therefore, it is possible to reduce the thickness variation of the processed substrate W due to the shape of the substrate W.

[0037] Hereinafter, an example of the substrate processing apparatus will be appended. [1] A substrate processing apparatus for planar processing a non-circular substrate adsorbed and held on a chuck table with a grindstone, wherein the chuck table is formed according to the shape of the substrate and includes an adsorbent capable of adsorbing and holding the substrate, and a compact embedded in the center of the adsorbent, and notches are formed on the outer periphery of the compact such that the contact area with the grindstone expands and contracts for each predetermined rotation angle of the chuck table in accordance with the change in the predicted contact area between the substrate and the grindstone when the substrate is processed with the grindstone during self-grinding in which the grindstone grinds the holding surface of the chuck table.

[0038] In addition, the present invention can be variously modified other than the above as long as it does not depart from the spirit of the present invention, and it is natural that the present invention extends to the modified ones. Also, the above-described embodiments and each modification example may be combined with each other.

Explanation of Reference Numerals

[0039] 1 ··· Substrate processing apparatus 2 ··· Holding means 21··· Chuck table 22··· Chuck spindle 23··· Adsorbent 24··· Compact 25 ··· Rotation angle detection unit 26 ··· Notch 3 ··· Processing means 31 ··· Grinding wheel 32 ··· Grinding wheel spindle 33 ··· Infeed mechanism 34 ··· Column 4 ··· Control device (control means) O ··· Rotation center (of the chuck table) W ··· Substrate

Claims

【Claim 1】 An adsorbent capable of adsorbing and holding a non-circular substrate, and a compact body including a first region which is a space for embedding the adsorbent and a second region disposed on the outer periphery of the first region, the compact body being rotatably provided, wherein the second region is formed with notches whose contact area with the grindstone expands and contracts for each rotation angle of the compact body in accordance with a change for each rotation angle of the compact body in a predicted contact area between the substrate and the grindstone when the substrate is processed by the grindstone when the surface of the compact body is ground by the grindstone. A chuck table characterized by this.

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