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 contacts a rotating grindstone 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 becomes 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] To achieve the above objective, the chuck table according to the present invention rotatably comprises an adsorbent capable of adsorbing and holding a non-circular substrate, and a dense body including a first region which is a space for embedding the adsorbent and a second region arranged on the outer periphery of the first region. The second region has a notch formed therein that expands and contracts with the grinding wheel at each rotation angle of the dense body, in accordance with the change in the expected contact area at each rotation angle of the dense body when the substrate is processed by the grinding wheel. [Effects of the Invention]

[0008] In this invention, the second region of the dense body is formed such that the amount of self-grinding by the grinding wheel grinding the surface of the dense body increases or decreases according to the rotation angle of the dense body, so as to cancel out thickness variations caused by localized changes in the amount of grinding of a non-circular substrate, the thickness variations of the processed substrate caused by the shape of the substrate can be reduced. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing a substrate processing apparatus to which a chuck table according to one embodiment of the present invention is applied. [Figure 2] A schematic diagram illustrating the process of self-grinding. [Figure 3] A plan view comparing the expected contact areas between the substrate and the grinding wheel at two locations within the substrate. [Figure 4] A plan view showing the shape of the chuck table. [Modes 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, numerical values, quantities, ranges, etc., of components, unless specifically indicated or clearly limited to a particular number in principle, the number is not limited to that particular number, and may be greater than or less than that number.

[0011] Furthermore, when referring to the shape, positional relationship, etc. of constituent elements, unless otherwise explicitly stated or it is clearly considered not to be so in principle, this includes things that are substantially similar or alike to those shapes, etc.

[0012] Furthermore, drawings may exaggerate features by enlarging characteristic parts to make them easier to understand, and the dimensional ratios of the components may not necessarily be the same as in reality.

[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 comprises a chuck table 21 and a chuck spindle 22.

[0015] The chuck table 21 has an adsorbent body 23 made of a porous material such as alumina on its upper surface, and a dense body 24 embedded approximately in the center of the adsorbent body 23. The chuck table 21 has a conduit (not shown) that runs through the inside and extends to the surface. The conduit is connected to a vacuum source, a compressed air source, or a water source via a rotary joint (not shown). When the vacuum source is activated, the substrate W placed on the adsorbent body 23 is adsorbed and held by the adsorbent body 23. When the compressed air source or water source is activated, the adsorption between the substrate W and the adsorbent body 23 is released.

[0016] The adsorbent 23 is formed in a shape corresponding to the substrate W when viewed from above. The dense body 24 is formed in a roughly circular shape with a portion of its outer circumference cut out when viewed from above, 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 rotate the chuck table 21 around the rotation axis 2a. The drive source for the chuck spindle 22 could be, for example, a servo motor.

[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, which will 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, 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 because the rotation angle of the chuck table 21 corresponds to the rotation angle of the servo motor.

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

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

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

[0022] The feed mechanism 33 raises and lowers the grinding wheel spindle 32 in the vertical direction. The feed mechanism 33 has a known configuration and is, for example, composed of a plurality of linear guides for guiding the moving direction of the grinding wheel spindle 32 and a ball screw slider mechanism for raising and lowering the grinding wheel spindle 32. The feed mechanism 33 is interposed between the grinding wheel spindle 32 and the column 34.

[0023] The operation of the substrate processing apparatus 1 is controlled by the control device 4. The control device 4 controls each component constituting 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 based on FIG. 2. FIG. 2 is a schematic diagram showing the state of self-grinding.

[0025] Self-grinding, as shown in Figure 2, is a process in which the grinding wheel 31 is brought close to the chuck table 21 by the infeed mechanism 33, and the holding surface 21a of the chuck table 21 is ground with the grinding wheel 31. Self-grinding is performed as needed to maintain the holding surface 21a of the chuck table 21 in a desired shape, and is generally performed when the chuck table 21 is replaced.

[0026] In the substrate processing apparatus 1, the amount of grinding 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 workpiece surface of the non-circular substrate W to process the substrate W in a planar manner, the amount of processing (grinding) of the substrate W is not stable within the plane.

[0027] The reasons for this will be explained below based on Figures 3 and 4. Figure 3 is a plan view comparing the expected contact areas between the substrate W and the grinding wheel 31 at two points within the substrate W. Figure 4 is a plan view showing the chuck table 21. In the following explanation, a square-shaped substrate W in plan view will be used as an example, but the shape of the substrate W is not limited to this.

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

[0029] Furthermore, when the grinding wheel 31 is brought into uniform contact with the substrate W across its entire surface, as the expected contact area between the substrate W and the grinding wheel 31 increases, the amount of material removed from the substrate W decreases, and the substrate W becomes thicker after processing. Therefore, comparing the expected contact areas S1 and S2 shown in Figure 3, it is predicted that the substrate W will be locally thicker after processing when the expected contact area S1 is larger.

[0030] Therefore, as shown in Figure 4, the dense body 24 is formed in a roughly circular shape with a portion of its outer circumference cut out, and is configured so that the contact area with the grinding wheel 31 changes appropriately along the rotational direction of the chuck table 21.

[0031] Specifically, notches 26 are provided on the outer circumference of the dense body 24 such that the contact area between the chuck table 21 and the grinding wheel 31 is inversely proportional to the expected contact area between the substrate W and the grinding wheel 31 when the substrate W is planar-machined with the grinding wheel 31.

[0032] In other words, if the expected contact area between the substrate W and the grinding wheel 31 within a predetermined rotation angle of the chuck table 21 is greater than the expected contact area (reference area) of the substrate W and the grinding wheel 31 as a reference, the area of ​​the notch 26 is set so that the contact area between the chuck table 21 and the grinding wheel 31 within this rotation angle is reduced. Note that the interval of the rotation angle of the chuck table 21 used to calculate the expected contact area can be changed arbitrarily.

[0033] Furthermore, if the expected contact area between the substrate W and the grinding wheel 31 is smaller than the reference area at a predetermined rotation angle of the chuck table 21, the area of ​​the notch 26 is set so that the contact area between the chuck table 21 and the grinding wheel 31 within this rotation angle is increased.

[0034] In this way, the contact area between the chuck table 21 and the grinding wheel 31 is expanded or contracted in inverse proportion to the expected contact area between the substrate W and the grinding wheel 31 based on the reference area.

[0035] Figure 4 shows the shape of the dense body 24 when the expected contact area S2 shown in Figure 3 is set as the reference area. That is, as the chuck table 21 rotates from (Θ-45 degrees) to Θ, the expected contact area between the substrate W and the grinding wheel 31 expands, and the area of ​​the notch 26 also gradually expands. As a result, the contact area between the chuck table 21 and the grinding wheel 31 during self-grinding gradually decreases inversely proportional to the increase in the expected contact area between the substrate W and the grinding wheel 31.

[0036] In this way, the substrate processing apparatus 1 according to this embodiment is formed such that the amount of self-grinding by the grinding wheel 31 grinding the holding surface 21a increases or decreases at each predetermined rotation angle of the chuck table 21, so as to offset variations in the thickness of the substrate W caused by changes in the expected contact area between the substrate W and the grinding wheel 31 at each predetermined rotation angle of the chuck table 21 when processing the substrate W with the grinding wheel 31, the amount of self-grinding by the grinding wheel 31 grinding the holding surface 21a increases or decreases at each predetermined rotation angle of the chuck table 21, thereby reducing variations in the thickness of the substrate W after processing caused by the shape of the substrate W.

[0037] Examples of circuit board processing equipment are provided below. [1] A substrate processing apparatus for planar processing of a non-circular substrate held by suction on a chuck table using a grinding wheel, The aforementioned chuck table is An adsorbent formed according to the shape of the substrate and capable of adsorbing and holding the substrate, A dense body with the aforementioned adsorbent embedded in the center, Equipped with, A substrate processing apparatus, wherein the outer circumference of the dense body has notches formed thereon that expand and contract with the grinding wheel at each predetermined rotation angle of the chuck table, in accordance with the change in the expected contact area between the substrate and the grinding wheel when the substrate is processed by the grinding wheel during self-grinding in which the grinding wheel grinds the holding surface of the chuck table.

[0038] Furthermore, the present invention can be modified in various ways other than those described above, as long as it does not depart from the spirit of the invention, and it goes without saying that the present invention extends to such modifications. In addition, the embodiments and modifications described above may be combined with each other. [Explanation of symbols]

[0039] 1...Substrate processing equipment 2...holding means 21. Chuck Table 22.. Chuck Spindle 23. Adsorbent 24...Dense body 25. Rotation angle detection unit 26... Notch 3...Processing means 31... Sharpening stone 32... Grinding wheel spindle 33. Infeed mechanism 34... Column 4. Control device (control means) O ···(Center of rotation of the chuck table) W ··· circuit board

Claims

[Claim 1] A chuck table applicable to a substrate processing apparatus capable of processing the surface of the chuck table and a non-circular substrate adsorbed onto the chuck table with a grinding wheel, An adsorbent capable of adsorbing and holding the aforementioned substrate, A dense body comprising a first region which is a space for embedding the adsorbent and a second region arranged on the outer periphery of the first region, is rotatably provided, The chuck table is characterized in that the second region has a notch formed therein in which, when the surface of the dense body is ground with the grinding wheel, the contact area with the grinding wheel expands or contracts for each rotation angle of the dense body, in accordance with the change in the expected contact area of ​​the dense body that the grinding wheel contacts the substrate during processing of the substrate.

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