JP7228438B2 - Substrate processing equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for processing a non-circular substrate.

2. Description of the Related Art In the field of semiconductor manufacturing, there is known a substrate processing apparatus for processing a semiconductor substrate such as a silicon wafer (hereinafter referred to as “substrate”) into a thin and flat surface.

Patent Literature 1 discloses a grinding apparatus that grinds a rectangular workpiece to a predetermined thickness by bringing a rotating grindstone into contact with the upper surface of a rectangular workpiece held on a chuck table.

Japanese Patent No. 5230982

However, when grinding is performed by bringing the grindstone into parallel contact with the rectangular workpiece held on the chuck table, the contact area between the grindstone and the rectangular workpiece is not constant for each predetermined rotation of the chuck table, and the contact area is relatively large. In large areas, the amount of grinding of the rectangular workpiece tends to be small, and in areas where the contact area is relatively small, the amount of grinding 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.

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

In order to achieve the above object, a substrate processing apparatus according to the present invention is a substrate processing apparatus for planar processing a non-circular substrate, comprising a chuck table capable of holding the substrate by suction, and rotating the chuck table. A holding means comprising a chuck spindle and a rotation angle detection unit capable of detecting the rotation angle of the chuck table; a grindstone for processing the substrate; a spindle for rotating the grindstone; an infeed mechanism for moving; and an expected contact area between the substrate and the grindstone when the substrate is processed by the grindstone according to a change in an expected contact area for each rotation angle of the chuck table. and control means for accelerating or decelerating a grinding speed at which the grindstone self-grinds the holding surface of the chuck table for each rotation angle.

According to this configuration, the grinding speed at which the grindstone self-grinds the holding surface of the chuck table is adjusted according to the change in the expected contact area between the substrate and the grindstone for each predetermined rotation angle of the chuck table when the substrate is processed by the grindstone. By accelerating and decelerating for each rotation angle of the chuck table, the grinding amount of the holding surface during self-grinding is increased or decreased so as to cancel out the thickness variations that locally change the processing amount of non-circular substrates. It is possible to reduce variations in the thickness of the substrate after processing due to the shape of the substrate.

Further, in the substrate processing apparatus according to the present invention, when the expected contact area is larger than a preset reference area, the control means accelerates the grinding speed of the grindstone from a preset reference speed. It is preferable to let

According to this configuration, even when the substrate and the grindstone are in contact with each other over a wider area than the reference area, it is possible to suppress a local decrease in the grinding amount within the contact area between the substrate and the grindstone.

Further, in the substrate processing apparatus according to the present invention, when the expected contact area is smaller than a preset reference area, the control means decelerates the grinding speed of the grindstone from a preset reference speed. It is preferable to let

According to this configuration, even when the substrate and the grindstone are in contact with each other narrower than the reference range, it is possible to suppress a local increase in the grinding amount within the contact area between the substrate and the grindstone.

In the present invention, since the amount of grinding of the holding surface during self-grinding is increased or decreased so as to offset the thickness variation in which the amount of grinding of a non-circular substrate locally changes, after processing due to the shape of the substrate Variation in substrate thickness can be reduced.

1 is a schematic diagram showing a substrate processing apparatus according to one embodiment of the present invention; FIG. The schematic diagram which shows the mode of self-grinding. FIG. 4 is a plan view comparing expected contact areas between the substrate and the grindstone at two locations within the substrate. The figure which shows a mode that the grinding speed of a whetstone is changed.

An embodiment of the present invention will be described based on the drawings. In addition, hereinafter, when referring to the number, numerical value, amount, range, etc. of the constituent elements, unless otherwise specified or clearly limited to a specific number in principle, it is limited to the specific number It does not matter if the number is greater than or less than a certain number.

In addition, when referring to the shape or positional relationship of components, etc., unless otherwise specified or in principle clearly considered otherwise, etc. include.

In addition, the drawings may exaggerate characteristic parts by enlarging them in order to make the characteristics easier to understand.

FIG. 1 is a front view showing the basic configuration of a substrate processing apparatus 1. FIG. A substrate processing apparatus 1 performs a grinding process on a wafer. A substrate processing apparatus 1 includes holding means 2 and processing means 3 .

The holding means 2 has a chuck table 21 and a chuck spindle 22 .

The chuck table 21 has an adsorbent 23 made of a porous material such as alumina on its upper surface, and a dense body 24 in which the adsorbent 23 is embedded substantially in the center. The chuck table 21 has a conduit (not shown) extending through the interior 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 adsorption member 23 is held by the adsorption member 23 by adsorption. Further, when the compressed air source or the water supply source is activated, the adsorption between the substrate W and the adsorbent 23 is released.

The adsorbent 23 is formed in a shape corresponding to the substrate W when viewed from above. Also, the dense body 24 is formed in a substantially circular shape when viewed from above, but the shape of the dense body 24 is not limited to this.

The chuck spindle 22 is configured to rotationally drive the chuck table 21 around the rotary shaft 2a. A drive source for the chuck spindle 22 may be, for example, a servomotor.

The holding means 2 further includes a rotation angle detector 25 . The rotation angle detection unit 25 detects the rotation angle of the chuck table 21 and sends a detection signal to the control device 4 described later each time the chuck table 21 rotates by a predetermined angle. For example, when the chuck spindle 22 is rotationally driven by a servomotor, the rotation angle detection unit 25 reads the rotation angle of the servomotor because the rotation angle of the chuck table 21 and the rotation angle of the servomotor correspond to each other. A rotation angle of the table 21 can be detected.

The processing means 3 includes a grindstone 31 , a grindstone spindle 32 and an infeed mechanism 33 .

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

The grindstone spindle 32 is rotatable around the rotary shaft 3a, and the grindstone 31 and the grindstone spindle 32 are configured to be integrally rotatable.

The infeed mechanism 33 raises and lowers the grindstone spindle 32 in the vertical direction. The infeed mechanism 33 has a known structure, and is composed of, for example, a plurality of linear guides that guide the movement direction of the grindstone spindle 32 and a ball screw slider mechanism that moves the grindstone spindle 32 up and down. The infeed mechanism 33 is interposed between the grindstone spindle 32 and the column 34 .

Operations of the substrate processing apparatus 1 are controlled by a 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, and the like. The functions of the control device 4 may be realized by controlling using software, or may be realized by operating using hardware.

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

As shown in FIG. 2, self-grinding is a process in which the whetstone 31 is brought close to the chuck table 21 by the infeed mechanism 33, and the whetstone 31 grinds the holding surface 21a of the chuck table 21. FIG. Self-grinding is performed as appropriate 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.

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 the processing amount (grinding amount) of the substrate W is stable within the surface when the processing surface of the grindstone 31 is in parallel contact with the processing surface of the substrate W having a non-circular shape and the substrate W is planarized. because it doesn't. The reason for this will be described below with reference to FIG. FIG. 3 is a plan view comparing expected contact areas between the substrate W and the grindstone 31 at two points within the substrate W. FIG. In addition, although the substrate W having a square shape in plan view will be described below as an example, the shape of the substrate W is not limited to this.

As shown in FIG. 3, the expected contact area S1 between the substrate W and the grindstone 31, which is set so that the processing surface of the grindstone 31 passes through the corner of the substrate W and the rotation center O of the chuck table 21, and the processing surface of the grindstone 31 is set to pass through the center of the side of the substrate W and the rotation center O, and the expected contact area S2 between the grindstone 31 and the substrate W is about twice as large as the expected contact area S2. I understand.

When the grindstone 31 is brought into contact with the substrate W uniformly over the entire surface, the grinding amount of the substrate W decreases as the expected contact area between the substrate W and the grindstone 31 increases, and the substrate W after processing decreases. becomes thicker. Therefore, when the expected contact areas S1 and S2 shown in FIG. 3 are compared, it is expected that the post-processing substrate W becomes locally thicker in the expected contact area S1.

Therefore, in the substrate processing apparatus 1, the infeed mechanism 33 is driven in accordance with the change in the expected contact area between the substrate W and the grindstone 31 as the chuck table 21 rotates when the substrate W is processed by the grindstone 31. The grindstone 31 is moved up and down to adjust the pressure with which the grindstone 31 is pressed against the holding surface 21a of the chuck table 21, thereby accelerating or decelerating the grinding speed at which the grindstone 31 grinds the holding surface 21a.

A procedure for accelerating and decelerating the grinding speed of the grindstone 31 will be specifically described below. FIG. 4 is a schematic diagram showing how the grinding speed of the grindstone 31 changes according to the rotation angle of the chuck table 21. As shown in FIG. A in FIG. 4 indicates the rotation angle of the chuck table 21 corresponding to the case where the grinding wheel 31 in FIG. B in the figure indicates the rotation angle of the chuck table 21 corresponding to the case where the substrate W and the grindstone 31 are in contact with each other so as to pass through the center of the side of the substrate W and the rotation center O (rotation angle=Θ-45 degrees).

[Preparation process]
First, the expected contact area between the substrate W and the grindstone 31 is calculated for each predetermined rotation angle of the chuck table 21 and stored in advance in the controller 4 . The rotation angle interval of the chuck table 21 for calculating the expected contact area can be arbitrarily changed.

In addition, the control device 4 compares the expected contact area (reference area) between the substrate W and the grindstone 31 and the expected contact area between the substrate W and the grindstone 31 , which is stored in advance in the control device 4 . (for each orientation of the substrate W), the grinding speed of the grindstone 31 during self-grinding is calculated and stored.

Specifically, when the expected contact area between the substrate W and the grindstone 31 is larger than the reference area, the grinding speed of the grindstone 31 during self-grinding is accelerated from a preset reference speed to increase the grinding amount of the holding surface 21a. is locally increased. The reference speed means a grinding speed at which the holding surface 21a can be ground into a desired shape when the holding surface 21a within the reference area is self-grinded. As a result, even if the expected contact area between the substrate W and the grindstone 31 is large during processing and the amount of grinding of the substrate W is locally reduced, the shape of the holding surface 21a is preconfigured so as to offset the amount of reduction. Since the substrate W is ground relatively low, variation in the thickness of the substrate W after processing can be suppressed.

Further, when the expected contact area between the substrate W and the grindstone 31 is smaller than the reference area, the grinding speed of the grindstone 31 during self-grinding is reduced from the reference speed to locally reduce the grinding amount of the holding surface 21a. As a result, even if the expected contact area between the substrate W and the grindstone 31 is small during processing and the amount of grinding locally increases, the shape of the holding surface 21a is relatively adjusted in advance so as to offset the increase. Since the substrate W is ground to a high height, variations in the thickness of the substrate W after processing can be suppressed.

The amount of change in the grinding speed of the grindstone 31 is calculated, for example, according to the ratio of the expected contact area between the substrate W and the grindstone 31 to the reference area, so that the grinding speed of the grindstone 31 is proportionally increased or decreased with respect to the reference speed. I don't mind. For example, when setting the expected contact area S2 shown in FIG. It is conceivable to set the grinding speed in the double expected contact area S1 to 0.5 μm/s.

[Self-grinding process]
First, the rotation angle detection unit 25 detects the rotation angle of the chuck table 21 during self-grinding and sends the rotation angle of the chuck table 21 to the control device 4 .

Based on the rotation angle of the chuck table 21 detected by the rotation angle detection unit 25, the control device 4 calls up the pre-stored grinding speed of the grindstone 31 for each rotation angle of the chuck table 21, and adjusts the grinding speed to match the grinding speed. Also, the infeed mechanism 33 is controlled to accelerate or decelerate the grinding speed at which the grindstone 31 grinds the holding surface 21a.

In this manner, the substrate processing apparatus 1 according to the present embodiment responds to the expected contact area in accordance with the change in the expected contact area of contact between the substrate W and the grindstone 31 when the substrate W processes the grindstone 31. By accelerating and decelerating the grinding speed at which the grindstone 31 self-grinds the holding surface 21a for each rotation angle of the chuck table 21, the variation in the thickness of the non-circular substrate W caused by the local variation in the processing amount is offset. Since the amount of grinding of the holding surface 21a during self-grinding is increased or decreased, variation in the thickness of the substrate W after processing due to the shape of the substrate W can be reduced.

In addition, the present invention can be modified in various ways without departing from the spirit of the present invention, and it is natural that the present invention extends to such modifications. Also, the above-described embodiments and modifications may be combined with each other.

REFERENCE SIGNS LIST 1 Substrate processing apparatus 2 Holding means 21 Chuck table 22 Chuck spindle 23 Attracting body 24 Dense body 25 Rotational angle detector 3 Machining Means 31 Grindstone 32 Grindstone spindle 33 Infeed mechanism 34 Column 4 Control device (control means)
O ... Rotation center (of chuck table) W ... Substrate

Claims (3)

A substrate processing apparatus for planarizing a non-circular substrate,
holding means comprising: a chuck table capable of holding the substrate by suction; a chuck spindle for rotating the chuck table; and a rotation angle detector capable of detecting a rotation angle of the chuck table;
processing means comprising a grindstone for processing the substrate, a spindle for rotating the grindstone, and an infeed mechanism for vertically moving the grindstone;
Grinding in which the grindstone self-grinds the holding surface of the chuck table in accordance with a change in an expected contact area between the substrate and the grindstone for each rotation angle of the chuck table when the substrate is processed by the grindstone. a control means for accelerating or decelerating the speed for each rotation angle;
A substrate processing apparatus comprising: 2. The method according to claim 1, wherein the control means accelerates the grinding speed of the grindstone from a preset reference speed when the expected contact area is larger than a preset reference area. Substrate processing equipment. 3. When the expected contact area is smaller than a preset reference area, the control means reduces the grinding speed of the grindstone from a preset reference speed. The substrate processing apparatus described.

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