JPH06155242A - Precision cutting device - Google Patents

Abstract

PURPOSE:To precisely control a movement quantity of an object to be controlled in a short time. CONSTITUTION:In a precision cutting device such as a dicing device containing a control means to control relative positional relation between a blade mounted on a spindle and a work piece such as a wafer held by a chuck table, the control device is provided with a ball screw 3 rotated by means of a motor 5, and a nut 6 screwed around the ball screw 3, and a finely moving body such as a piezoelectric element 7 is provided between the nut 6 and an object to be controlled moving by movement of the nut 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision cutting device such as a dicing device.

[0002]

2. Description of the Related Art In a precision cutting device such as a dicing device, the relative positional relationship between a blade mounted on a spindle and an object to be processed such as a wafer held on a chuck table has been conventionally shown in FIG. Motor a as shown
The position control means is provided with a ball screw b rotated by and a nut c screwed to the ball screw b. That is, a block d for mounting a controlled object such as a spindle or a chuck table is fixed to the nut c, and the actual movement amount of this block d in the Y-axis direction is detected by a position detection device e. Value to CPU
(Not shown) is fed back, and the movement distance thereof is properly controlled to enable precise positioning.

[0003]

According to the above-mentioned conventional position control means, the motor a rotates the ball screw b so that the nut c moves in the Y-axis direction by a predetermined distance. Since there is an error in the actual amount of movement, the ball screw b must be rotated many times until the target amount of movement is reached while checking the actual amount of movement with the position detection device e, and the movement operation must be repeated. ,
This will take time and reduce work efficiency. The present invention has been made to solve such conventional problems, and an object thereof is to provide a precision cutting device capable of precisely controlling a target movement amount of a controlled object in a short time. It is a thing.

[0004]

As a means for technically solving this problem, the present invention relates to a relative relationship between a blade mounted on a spindle and a workpiece such as a wafer held on a chuck table. In a precision cutting device such as a dicing device including a control means for controlling a positional relationship, the control means includes a ball screw rotated by a motor and a nut screwed to the ball screw, and the nut is moved by the movement of the nut and the nut. The gist is that a fine moving body such as a piezoelectric element is interposed between the controlled body and the controlled body.

[0005]

[Operation] Even if an error occurs between the target movement amount and the actual movement amount, the error can be corrected by expanding and contracting the piezoelectric element in the Y-axis direction, and the controlled object can be moved in a short time. Can be precisely positioned.

[0006]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a Y-axis base which is a base of the positioning device, and a slide table 2 which is a controlled object is provided slidably in the Y-axis direction.

Reference numeral 3 is a ball screw, both ends of which are supported by bearing portions 4 and 4'standingly provided on the Y-axis base 1, and forward and reverse rotation by a motor 5 attached to the bearing portion 4'side. To be made.

Reference numeral 6 denotes a nut screwed into the ball screw 3, which is moved in the Y-axis direction by the rotation of the ball screw 3. The nut 6 has a piezoelectric element 7 as a fine moving body and a spring as a preload member. A block 9 is attached via 8 and this block 9 is fixed on the slide table 2. Therefore, when the nut 6 moves due to the rotation of the ball screw 3, the slide table 2 is moved in the Y-axis direction as the nut 6 moves.

Reference numeral 10 denotes a Z-axis moving mechanism provided on the slide table 2. By rotating the vertical screw rod 12 with a Z-axis driving motor 11, a nut 13 screwed onto the vertical screw rod 12 is mounted. A spindle holder 14 is fixed to the nut 13, and a spindle 15 having a mounter 16 for mounting a rotary blade is held on the spindle holder 14, so that the Z-axis movement is eventually performed. The mechanism 15 enables the spindle 15 to move in the Z-axis direction in an arc with reference to the reference axis 14 '.

Although not shown, a chuck table for holding a wafer and performing dicing by a rotating blade mounted on the mounter 16 is formed so as to be movable in the X-axis direction relative to the Y-axis base 1.

The position control means of the precision cutting device according to the present invention is constructed as described above, and in the dicing device or the like, the spindle 15 is moved to Y by the movement of the slide table 2.
The rotary blade is moved in the axial direction to align with the cutting line of the wafer (not shown), the spindle 15 is moved in the Z axis direction to adjust the cut amount of the rotary blade, and then the chuck table holding the wafer is moved in the X axis direction. Although the dicing is performed by moving it to, the positioning in the Y-axis direction, which is particularly important during this dicing, can be performed accurately in a short time.

In this case, first of all, the first stage of alignment is carried out by rotating the motor 5 by an amount commensurate with the moving distance of the block 9 according to a command from the CPU (not shown).
As shown in FIG. 2, the rotation of the motor 5 is transmitted to the ball screw 3 via the coupling 17, and the nut 6 linearly moves to move the block 9 in the Y-axis direction. At this time, the piezoelectric element 7 is held as it is. After the block 9 is moved, the Y-axis moving distance is fed back from the position detecting device 18 to the CPU, and the second-stage positioning is performed.

That is, when the feedback value is different from the initial command value, a correction command is issued from the CPU to expand / contract the piezoelectric element 7 and correct the block 9 to the proper position.
The piezoelectric element 7 can be finely adjusted with a resolution of 0.1 μm or less, and the response speed is as high as 10 μs, so that the block 9 can be positioned accurately in a short time.

Although the piezoelectric element is used as the fine moving body in the above embodiment, an electrostrictive element may be used without being limited to this, and since the electrostrictive element has a minimum hysteresis as compared with the piezoelectric element, a servo is used. Suitable for driving. Therefore, when the electrostrictive element is used for fine movement drive of the precision positioning mechanism, hysteresis correction by software or the like is unnecessary. Further, when the fine moving body is arranged near the center of gravity of the controlled body and arranged close to the ball screw, the responsiveness of the controlled body during fine movement is improved, and it is sufficient even if there is no spring as a preloading member. It is possible to secure the precision of fine movement.

[0015]

As described above, according to the present invention,
In a precision cutting device such as a dicing device, a nut screwed into a ball screw rotated by a motor,
Since a fine moving body such as a piezoelectric element is interposed between the controlled body that is moved by the movement of the nut, the piezoelectric element can be expanded and contracted even if an error occurs between the target movement amount and the actual movement amount. The error can be corrected instantly by
The controlled object can be accurately positioned in a short time.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part showing an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a portion provided with a fine moving body such as a piezoelectric element.

FIG. 3 is an explanatory diagram of a conventional example.

[Explanation of symbols]

1 ... Y-axis base 2 ... Slide table 3 ... Ball screw 4, 4 '... Bearing part 5 ... Motor
6 ... Nut 7 ... Piezoelectric element 8 ... Spring
9 ... Block 10 ... Z-axis moving mechanism 11 ... Z-axis drive motor 12 ... Vertical screw rod 13 ... Nut 14 ... Spindle holder 14 '... Reference axis 15 ... Spindle
16 ... Mounter 17 ... Coupling 18 ... Position detection device

Claims (1)

[Claims] 1. A precision cutting device such as a dicing device including a control means for controlling the relative positional relationship between a blade mounted on a spindle and a workpiece such as a wafer held on a chuck table. Is equipped with a ball screw rotated by a motor and a nut screwed to the ball screw, and a fine moving body such as a piezoelectric element is interposed between the nut and a controlled body which is moved by the movement of the nut. Precision cutting equipment.