JP2003062730A - Chucking means for grinding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chucking means which can prevent the occurrence of troubles, such as a crack, a wobble, during injection of mixed fluid including compressed air from an absorbing surface of a chuck table when plate-like ground workpieces held by absorption on the chuck table of a grinding apparatus are removed from the chuck table by means of a removal means. SOLUTION: The chucking means is provided with a releasing pipe line for connecting a mixed fluid pipe line, which connects the chuck table with a mixed fluid source via a shut-off valve, with a drain via a releasing shut-off valve by making the mixed fluid pipe line branch at a position between the mixed fluid source and the shut-off valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck means for adsorbing and holding a work piece in a plate-like work piece grinding machine such as a semiconductor wafer.

[0002]

2. Description of the Related Art A semiconductor wafer on which a large number of circuits such as ICs and LSIs are formed has its back surface ground by a grinding machine in order to make a semiconductor chip as a product thin and small. This grinding apparatus includes chuck means for adsorbing and holding a thin plate semiconductor wafer, grinding means for grinding the wafer held by the chuck means, and unloading means for removing the wafer after grinding from the chuck means. There is. The semiconductor wafer has, for example, a substantially disc shape with a diameter of about 200 mm, and has a thickness of 100 μm for the above-mentioned miniaturization.
Hereafter, it is desired to grind thinly to 50 μm or less.

In this grinding machine, a semiconductor wafer is
First, it is adsorbed and held by the porous chuck table of the chuck means, and the back surface on which no circuit is formed is ground by the grinding means. The ground wafer is adsorbed by the unloading means and removed from the chuck table. At the time of this unloading, after the suction force of the chuck table is cut off, in order to easily separate the thin plate wafer attached to the surface of the chuck table, compressed air and water from the inside of the chuck table toward the suction surface. The mixed fluid is jetted so that the wafer is lifted up from the suction surface so that the wafer is not forcibly peeled off from the suction surface by the carry-out means.

[0004]

The chuck means of the conventional grinding apparatus having the above-mentioned configuration has the following problems to be solved.

That is, when a plate-like workpiece such as a semiconductor wafer is removed from the suction surface by the unloading means,
At the moment when the on-off valve was opened to eject the mixed fluid onto the adsorption surface, the mixed fluid containing compressed air spouted momentarily and cracked into a thin plate-like workpiece such as a ground semiconductor wafer. There are problems such as causing noise and causing the workpiece to dance.

The present invention has been made in view of the above-mentioned facts, and its technical problem is to carry out a plate-shaped workpiece, which is sucked and held by a chuck table of a grinding machine and ground, from a chuck table by a carrying-out means. When the mixed fluid containing compressed air is jetted from the suction surface of the chuck table, the chuck means is provided so as not to cause defects such as cracks and dances on the workpiece. .

[0007]

In the present invention, as chuck means of a grinding apparatus for solving the above technical problems,
Chuck means for sucking and holding a plate-shaped workpiece in a grinding device, the chuck means having a chuck table having a porous suction surface for mounting the workpiece,
A suction passage that connects a suction source to the chuck table via a suction opening / closing valve, a mixing fluid passage that connects a mixed fluid source containing compressed air to the chuck table via a mixed fluid opening / closing valve, and a mixing fluid passage to a mixing fluid source And a release path that branches between the fluid on-off valve and connects to the drain via the release on-off valve,
A chuck means of a grinding apparatus is provided, wherein a pressure of the mixed fluid ejected from the adsorption surface is adjusted by opening a release passage by the release opening / closing valve.

Then, a part of the mixed fluid containing compressed air ejected to the adsorption surface of the chuck table can be released to the drain through the opening / closing valve through the release passage, and the pressure of the mixed fluid is released. Try to lower it.

In a preferred embodiment, a workpiece that has been suction-held and ground on a chuck table in a state where the suction on-off valve is opened and the mixed fluid on-off valve is closed,
When removing from the chuck table by the unloading means,
(1) First, the suction on-off valve is closed to shut off the suction force of the chuck table, (2) Next, the release on-off valve is opened to reduce the pressure in the mixed fluid passage, and (3) After that, the mixed fluid on-off valve is opened to set the pressure. The mixed fluid with the reduced pressure is ejected from the chuck table. Further, the suction on / off valve, the mixed fluid on / off valve, and the release on / off valve are provided with control means for controlling opening / closing operations. Further, the work piece is a semiconductor wafer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the chuck means of a grinding apparatus constructed according to the present invention in the chuck means of a grinding apparatus for grinding a semiconductor wafer, which is a plate-shaped workpiece, will be described. It will be described in more detail with reference to the drawings.

With reference to FIG. 1, an outline of a semiconductor wafer grinding apparatus, generally designated by reference numeral 2, will be described. The grinding device 2 includes a chuck means 6 having three circular chuck tables 4 for sucking and holding a semiconductor wafer, a grinding means 8 for grinding the wafer held on the chuck table 4, and a chuck table for the wafer after grinding. And a carrying-out means 10 for removing from 4.

The chuck means 6 comprises a turntable 14 having the above-mentioned three chuck tables 4 on the upper surface of the apparatus housing 12, and the chuck table 4 comprises a suction surface S formed of a porous ceramic plate. (The chuck means 6 will be described in detail later). The grinding means 8 includes a rough grinding unit 8a and a finish grinding unit 8b provided at one end of the apparatus housing 12. The carry-out means 10 includes a swing arm 10a and a suction pad 10b at the tip thereof.

In the carry-in / carry-out area of the turntable 14, the semiconductor wafer before processing is carried into the chuck table 4 from the pre-process section 18 by the carrying-in means 16 and placed on the chuck table 4. By rotating the turntable 14 in the direction of the arrow, the chuck table 4 moves between the rough grinding processing area and the finish grinding processing area, and is ground while the processing liquid is supplied. The ground wafer is adsorbed by the adsorption pad 10b of the carry-out means 10 in the carry-in / carry-out area and carried to the next process section 20.

The chuck means 6 will be described with reference to FIG. 2 as well as FIG. 1, mainly FIG. Chucking means 6
Is a suction path 26 that connects three chuck tables 4 formed of the above-mentioned porous ceramic plate and having a suction surface S and suction sources 22 such as vacuum tanks to the respective chuck tables 4 via suction on-off valves 24. And a compressed air source 28 such as an air tank on each chuck table 4.
And a water source 30 are connected to each other via a mixed fluid opening / closing valve 34, and a mixed fluid passage 36 is connected to the mixed fluid source 32 and three mixed fluid opening / closing valves 34.
And a release passage 42 that branches to and connect to the drain 40 via the release opening / closing valve 38.

The chuck table 4 is the turntable 1
4 is rotatably arranged in a horizontal plane and has a disk-shaped base 4a.
And a disk-shaped suction-holding chuck 4c attached to a recess 4b opened upward on the upper surface of the base 4a, and a rotary shaft portion 4d protruding to the center of the lower surface of the base 4a. The rotary shaft portion 4d is rotatably mounted on the turntable 14. A passage 4e communicating with the recess 4b is formed in the rotary shaft portion 4d, and the suction passage 26 and the mixed fluid passage 36 are connected to this passage.

The suction on-off valve 24, the mixed fluid on-off valve 34, and the release on-off valve 38 are two-position electromagnetic on-off valves. The chuck means 6 is provided with a controller 44 which is a control means for controlling the opening / closing of these opening / closing valves.
In the state where the controller 44 is not energized and excited by the controller 44 (the state shown in FIG. 2), each of them is positioned in the closed position, and blocks the suction passage 26, the mixed fluid passage 36, and the release passage 42.

The size of the opening / closing valve 38 is such that when the open path 42 is communicated with the drain 40 and a part of the mixed fluid of the mixed fluid path 36 is released to the drain 40 in the excited open state, the chuck table 4 is opened. The pressure of the mixed fluid ejected from the adsorbing surface S is set to be reduced.

The controller 44 controls the sequence of opening / closing operations of the suction opening / closing valve 24, the mixed fluid opening / closing valve 34, and the release opening / closing valve 38, and is formed by a microcomputer, an electromagnetic relay, an electromagnetic valve driver, and the like. . That is, the controller 4 sucks and holds and grinds the chuck table 4 (the suction opening / closing valve 24 is opened and the mixed fluid opening / closing valve 34 is closed) positioned in the carry-out area by rotating the turntable 14. When the semiconductor wafer, which is a workpiece, is taken out by the carry-out means 10, (1) first, the excitation of the suction opening / closing valve 24 is stopped and the suction force of the chuck table 4 is removed, and (2) then the release opening / closing valve 38 is excited. Open to lower the pressure in the mixed fluid passage 36,
(3) After that, the mixed fluid opening / closing valve 34 is excited to open the mixed fluid whose opening pressure is reduced to the suction surface S of the chuck table 4.
To squirt from. Then, the semiconductor wafer is used as the carry-out means 1
When it is carried out from the chuck table 4 by 0, the release opening / closing valve 38 and the mixed fluid opening / closing valve 34 are closed by stopping the excitation.

The operation of the chuck means 6 of the grinding apparatus as described above will be described with reference to FIGS. 1 and 2.

The chuck means 6 has a release passage 4 having a release fluid opening / closing valve 38 for branching the mixed fluid passage 36 for supplying the mixed fluid to the chuck table 4 and releasing it to the drain 40.
2, the opening / closing valve 38 is opened to release a part of the mixed fluid to the drain 40, whereby the pressure of the mixed fluid can be lowered and the momentum of the mixed fluid ejected from the chuck table 4 can be suppressed. The work piece such as a thinly ground semiconductor wafer can be removed from the chuck table 4 without causing defects such as cracking and dancing.

When the workpiece is not placed on the suction surface S of the chuck table 4, the release opening / closing valve 38 of the release path 42 is closed, the suction opening / closing valve 24 is closed, and the mixed fluid opening / closing valve 34 is opened. The suction holding chuck 4c and the suction surface S of the chuck table 4 can be cleaned by jetting a high-pressure mixed fluid.

Although the present invention has been described in detail above based on the embodiments, the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the present invention, for example, as described below. It can be transformed or modified.

(1) Chucking means: In the present embodiment, the chucking means 6 is provided with three chuck tables 4, but the number is not limited to three.

(2) Control means: In the present embodiment, a controller 44 which is a control means for opening and closing the suction on-off valve 24, the mixed fluid on-off valve 34, and the release on-off valve 38.
However, each may be operated independently in a predetermined order without using the control means.

(3) Opening / closing valve: In the present embodiment, the opening / closing valve 38 having a predetermined capacity is used, but various kinds of capacity are prepared according to the grinding device. Alternatively, a release opening / closing valve having a large capacity may be used to restrict the release path 42, or a variable restrictor may be provided.

[0026]

According to the chuck means of the grinding apparatus constructed according to the present invention, when the plate-like workpiece which is suction-held on the chuck table of the grinding apparatus and which has been ground is carried out from the chuck table by the carrying-out means. In addition, when the mixed fluid containing compressed air is jetted from the suction surface of the chuck table, it is possible to prevent the work piece from suffering defects such as cracking and dancing.

[Brief description of drawings]

FIG. 1 is a perspective view of a grinding apparatus including a chuck means configured according to the present invention.

FIG. 2 is a configuration circuit diagram of chuck means.

[Explanation of symbols]

2: Grinding device 4: Chuck table 6: Chuck means 10: Carrying out means 22: suction source 24: Suction on-off valve 26: suction path 32: Mixed fluid source 34: Mixed fluid on-off valve 36: Mixed fluid path 38: Opening / closing valve 40: Drain 42: Liberation path 44: Controller (control means) S: Adsorption surface

Continued front page    F-term (reference) 3C016 CE05 DA05                 3C034 AA08 BB73 CB11 DD10                 3C043 BA09 BA16 BA17 CC04 DD05                       EE04

Claims (4)

[Claims] 1. A chuck means for sucking and holding a plate-shaped workpiece in a grinding device, the chuck means comprising a chuck table having a porous suction surface for mounting the workpiece, and a chuck. A suction path connecting a suction source to the table via a suction on-off valve, a mixed fluid path connecting a mixed fluid source containing compressed air to the chuck table via a mixed fluid on-off valve, and a mixed fluid path to a mixed fluid source and a mixed fluid A release path that branches from the on-off valve and connects to the drain via the release on-off valve, and the pressure of the mixed fluid ejected from the adsorption surface is adjusted by releasing the release path by the release on-off valve. A chucking means for a grinding machine, which is characterized in that: 2. When the workpiece to be sucked and held by the chuck table and ground is taken out from the chuck table by the unloading means in the state where the suction on-off valve is opened and the mixed fluid on-off valve is closed, (1) First, The suction on-off valve was closed to shut off the suction force of the chuck table, (2) the release on-off valve was then opened to lower the pressure in the mixed fluid passage, and (3) the mixed fluid on-off valve was then opened to lower the pressure. The chuck means of the grinding apparatus according to claim 1, wherein the mixed fluid is ejected from the chuck table. 3. The chuck means of the grinding apparatus according to claim 2, further comprising control means for controlling opening / closing operations of the suction opening / closing valve, the mixed fluid opening / closing valve and the release opening / closing valve. 4. The chuck means of the grinding apparatus according to claim 1, wherein the work piece is a semiconductor wafer.