TW201413862A - Clamping device capable of monitoring wafer state and monitoring method - Google Patents

Abstract

A clamping device capable of monitoring the wafer state and a monitoring method is disclosed. The clamping device comprises a rotatable chuck, a rotating shaft arranged in the geometric center of the chuck, a sensor fixed on the rotating shaft, and at least three clamping elements arranged on the chuck. According to the clamping device, the releasing and clamping of the wafer is realized by the relative rotation of a cam in the clamping device and the chuck, and the clamping state of the wafer is further detected accurately by the sensor which can avoid loosening or damaging the wafer when the clamping force is too little or too great so as to increase the stability.

Description

Clamping device and method for monitoring semiconductor wafer state function

The present invention relates to the field of semiconductor integrated circuit component cleaning technology, and more particularly to a clamping device and method having the function of monitoring the state of a semiconductor wafer.

The present application claims priority to PCT Application No. 201210348350.8, filed on Sep.

As feature sizes of integrated circuits enter the deep submicron stage, wafer cleaning has evolved from the initial simple trench cleaning to more accurate single-chip cleaning. In the case of single-chip cleaning, the chuck is required to fix the wafer for rotation. However, if the chuck is too tightly clamped, it is easy to crush the wafer, and the card is not tight. When the rotation operation is performed, the wafer is easily detached from the chuck and broken. In both cases, the wafer is lost, which greatly increases the production cost of wafer fabrication.

The technical problem to be solved in this case is how to accurately determine whether the wafer is stuck on the chuck to reduce the risk of wafer breakage.

In order to achieve the above object, the present invention provides a clamping device having a function of monitoring a state of a semiconductor wafer, the clamping device comprising: a rotatable chuck, a rotating shaft located at a geometric center of the chuck, and fixed to the rotating shaft on a sensor and at least three clamping elements distributed on the chuck.

Preferably, a compression spring is mounted on each of the clamping elements.

Preferably, at least two movable stops are distributed on the chuck.

Preferably, the clamping device further includes a cam rotatable relative to the chuck, one end of the clamping member being in contact with the cam.

Preferably, a pulley or bearing is provided at the contact end of the clamping element with the cam.

Preferably, the cam is mounted to the chuck by a bearing.

Preferably, the cam is provided with at least two oblong holes.

Preferably, the chuck is provided with a structure for restricting rotation of the clamping member relative to the chuck along the axis of the clamping member.

Preferably, the clamping device further comprises a driving rod located in the oblong hole.

Preferably, the sensor is a fiber microbend sensor.

The present invention further provides a method for monitoring the state of a semiconductor wafer, in the process of performing a clamping operation on the semiconductor wafer by the clamping device, detecting a change in the displacement of the fiber output by the sensor, and determining the fiber that detects the output. When the magnitude of the change in displacement is within a predetermined threshold range, a signal is generated to indicate that the semiconductor wafer is in an expected state.

According to the above description, the case relaxes or clamps the wafer by the relative rotation of the cam and the chuck, and the structure is simple and easy to implement, and the wafer is accurately measured by the sensor to prevent the wafer from being clamped, thereby avoiding the crystal caused by the clamping force being too small. The round clamping is not tight, or the damage to the wafer is caused by excessive clamping force, and the stability is improved.

The above and other features and advantages of the present invention will become more apparent from the description of the appended claims.

Hereinafter, a holding device having a function of monitoring the state of a semiconductor wafer according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein like elements will be described with the same reference numerals.

The purpose of the present invention is to accurately determine whether a wafer is jammed on a chuck to reduce the risk of wafer breakage. The invention determines whether the wafer is clamped by monitoring the deformation of the optical fiber by placing a fiber microbend pressure sensor at the center of the bottom of the wafer; and then adjusting the chuck according to the state of the fed wafer. The apparatus of the present invention enables the clamping process operation to be accurately stopped at the end of the operation, i.e., at this point the wafer is in a desired state.

As shown in FIG. 1 and FIG. 2, the clamping device of the present invention comprises: a hollow rotating shaft 1-1 which is rotatable under the driving of the driving device, and a chuck 1-2 which is rotated by the rotating shaft 1-1, passes through The bearings 1-4 are mounted on the chucks 1-2 with cams 1-3 (which are rotatable relative to the chuck) and the clamping elements 1-5 distributed along the chucks 1-2. The cam 1-3 has at least two oblong holes, and the two driving rods 1-11 are inserted into the oblong hole by the driving device (not shown) to fix the cam 1-3, and the driving chuck 1-2 is rotated by a certain angle, thereby The relative rotation of the chuck 1-2 (clamping member) and the cam 1-3 is achieved. Rotation of the chuck 1-2 relative to the cams 1-3 causes the clamping members 1-5 to move radially along the chuck to effect opening and clamping of the wafer. There are at least two blocks 1-12 distributed on the chuck 1-2, and the blocks 1-12 can be up and down Telescopic, move left and right. When the wafer clamping operation is adjusted, the stopper shrinks into the chuck 1-2; when the sensor 1-6 sends a signal to judge that the wafer has been clamped, the stopper 1-12 in the chuck 1-2 Pop-up, left and right adjustment, the position of the chuck 1-2 and the cam 1-3 is fixed, no relative rotation occurs, and the height and position of the stopper 1-12 are also fixed. At least three clamping elements are distributed along the chuck 1-2, one end of the clamping element 1-5 is pressed against the cam by the compression spring 1-10, and the clamping element 1-5 can be along the chuck 1-2 Radial sliding relative to each other. The clamping element 1-5 can follow the chuck 1-2 to rotate along the axis of rotation of the chuck 1-2. On the chuck 1-2 there is a structure which limits the rotation of the clamping element 1-5 relative to the chuck 1-2, so that the clamping element 1-5 can only be translated along the chuck 1-2. The contact end of the clamping member 1-5 and the cam 1-3 may be provided with a pulley or a bearing so that the friction between the two is changed from sliding friction to rolling friction.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a side elevational view of a clamping device of the present invention showing some of the components of an exemplary chuck device and a hollow shaft including a fiber optic microbend sensor in cross-section, in accordance with an embodiment of the present invention. In Fig. 1, the hollow rotating shaft 1-1 drives the chuck 1-2 to rotate about the rotation axis A-A, and the cam 1-3 is mounted on the chuck 1-2 through the bearing 1-4, and is rotatable relative to the chuck. At least three clamping elements 1-5 are mounted on the chuck 1-2. The rotation of the clamping element 1-5 about its center of rotation B-B, the clamping element 1-5 can only move radially along the chuck 1-2.

Figure 2 is a bottom plan view of the clamping device of the present invention (with the lower cover 1-8 removed) clamping the wafer. A driving device (not shown) drives the lever 1-11 into the oblong hole of the cam 1-3 from below, and drives the rotating shaft 1-1 to rotate by a certain angle in a direction opposite to ω (the direction in which the process rotates), and rotates Axis 1-1 drives the card The disk 1-2 rotates synchronously, and since the cams 1-3 are restricted by the drive levers 1-11, the chucks 1-2 cannot be rotated. Thus, the chuck 1-2 drives the clamping member 1-5 to rotate by a certain angle α (the chuck is rotated relative to the cam), and the cam 1-3 pushes the clamping member 1-5 outward to loosen the wafer 1-9 and Can be opened, as shown in Figure 3. In contrast, driving the rotary shaft 1-1 in the same direction as ω drives the chuck 1-2 to rotate by a certain angle. Since the cam 1-3 is restricted by the drive lever 1-11, the chuck 1-2 cannot be rotated. Thus, the chuck 1-2 drives the clamping member 1-5 to rotate by a certain angle, and the clamping member 1-5 is retracted along the chuck 1-2 to achieve the clamping of the wafer 1-9, as shown in FIG. During adjustment of the wafer 1-9 clamping, the stops 1-12 are retracted into the chuck 1-2 to ensure that the relative rotation of the chuck 1-2 and the cam 1-3 is not interfered. Sensors 1-6 will monitor the clamping state of wafers 1-9 and feed the signals back to the chucks to instantly adjust wafer 1-9 clamping conditions. When the wafer 1-9 is clamped, the stopper 1-12 is ejected from the chuck 1-2, and the positions of the two stoppers 1-12 are adjusted left and right to make the chuck 1-2 and the cam 1-3 The relative position remains fixed, and then the drive rod 1-11 is lowered out of the oblong hole to ensure that the chuck lower cover 1-8 does not interfere with the drive rod 1-11 when continuously rotating, providing a process for continuously rotating the chuck in the direction of ω. may.

The sensor 1-6 is disposed on the hollow rotating shaft 1-1 to facilitate monitoring whether the semiconductor wafer is clamped. Figure 5 is a simplified view of the clamping device of Figure 1. As shown in FIG. 5, the sensor 1-6 is fixed to a central portion of the rotating shaft 1-1. The sensor 1-6 can be attached to the rotating shaft 1-1 using any suitable technique. When the sensor 1-6 is a fiber microbend sensor, the pressure variation of the air concentrated between the fiber microbend sensor 1-6 and the back of the wafer 1-9 can be detected.

Please refer to FIG. 6 , which is a schematic diagram of the mechanism of the fiber microbend sensor. Figure. The isolating diaphragm 6-3 and the flat diaphragm 6-4 are welded and sealed on the casing, and the two are filled with the oil 6-5, and the movable tooth plate 6-6 of the microbend sensor is bonded to the flat diaphragm 6- At the hard center of 4, the fixed tooth plate 6-7 of the microbend sensor is bonded to the fixed platform 6-10, and the position of the fixed tooth plate 6-7 can be adjusted by adjusting the screw, that is, the sensor can be adjusted. Zero position, both ends of the movable tooth plate 6-6 are slightly protruded from the tooth peak, and are processed into a V shape. When the pressure is overloaded, both ends of the microbend sensor movable tooth plate 6-6 are placed on the fixed tooth plate 6- 7 on both ends of the plane, thereby preventing the tooth ends from continuing to press the fibers 6-9.

The gas on the back side of the wafer 1-9 is applied to the isolating diaphragm 6-3 of the optical microbend sensor 1-6 via the pressure guiding port, and the pressure is uniformly transmitted to the flat diaphragm 6 through the eucalyptus oil 6-5. 4, so that the flat center piece 6-4 is displaced at the hard center, and the movable tooth plate 6-6 of the sensor 1-6 is applied to the transmission fiber 6-9, so that the transmitted light in the optical fiber generates microbend loss. By detecting the change in the output light, the magnitude of the pressure can be determined. When the pressure of the eucalyptus oil itself is not applied by the pressure of the external gas, the output of the light is made lossless by adjusting the screw 6-8, and the zero output is obtained. During the clamping of the wafer 1-9, the output of the fiber changes as the wafer is jammed. The fiber values determined by the fiber microbend sensors 1-6 are continuously transmitted to the signal processor 5-1, which is configured to generate a signal 5-2 when the wafer is clamped. Signal 5-2 can be of any form, and in one embodiment, the signal is in the form of a mark that stops the rotating electrical machine and thereby terminates the clamping operation of the wafer.

Hereinafter, how to use the pressure value provided by the fiber microbend sensor to determine whether the wafer is clamped or not is specifically described according to an embodiment of the present invention. Figure 7 is a graph of pressure versus time for an exemplary fiber microbend sensor. As shown As shown in Figure 7, in stage A, it is a period of time before the wafer clamping starts. Since the wafer is not clamped, the stress of the wafer is zero, and no gas on the back of the wafer acts on the fiber microbend sensor. The pressure at this stage is zero. During phase B, it is the stage at which the wafer begins to clamp. As the clamping component contacts the wafer, the wafer gradually generates stress, and the gas on the back of the wafer gradually acts on the micro-bend sensor of the fiber. Gradually rise. In stage C, since the wafer has been clamped, the stress on the wafer is substantially constant and the pressure generated by the gas on the backside of the wafer is maintained at a substantially constant level. Thus, the region near the beginning of phase C, i.e., the region near the point at which the pressure reaches a constant level, is a reliable indication of wafer clamping.

The present invention further provides a method of monitoring the state of a semiconductor wafer. In the method, the displacement change of the optical fiber outputted by the micro-bend pressure sensor of the optical fiber is detected when the wafer is clamped, and when the displacement of the optical fiber of the detection output is determined to be substantially constant, such as maintaining a substantially constant level, A signal indicating that the wafer is in a desired state. In an embodiment, the continued clamping of the clamping element is stopped in response to the signal.

It can be seen from the above embodiment that the present invention detects the change of the output light of the micro-bend pressure sensor of the optical fiber by placing a fiber micro-bend pressure sensor at the center of the bottom of the wafer, and the displacement of the fiber of the detection output is substantially unchanged. At this time, a signal indicating that the wafer is in a desired state is generated, and in response to the signal, the chucking operation on the wafer is stopped.

The above is merely exemplary and not limiting. Any equivalent modifications or changes made to the spirit and scope of this case shall be included in the scope of the appended patent application.

1-1‧‧‧Rotary axis

1-2‧‧‧ chuck

1-3‧‧‧ cam

1-4‧‧‧ bearing

1-5‧‧‧Clamping components

1-6‧‧‧Sensor

1-7‧‧‧Upper cover

1-8‧‧‧Under the cover

1-9‧‧‧Semiconductor wafer

1-10‧‧‧Compressed spring

A-A‧‧‧Rotary axis rotation center

B-B‧‧‧Clamping element rotation center

1-11‧‧‧ drive rod

1-12‧‧‧blocks

5-1‧‧‧ signal

5-2‧‧‧Signal Processor

6-1‧‧‧Shell

6-2‧‧‧ Back cover

6-3‧‧‧Isolation diaphragm

6-4‧‧‧ flat diaphragm

6-5‧‧‧矽油

6-6‧‧‧Microbend probe moving plate

6-7‧‧‧Microbend probe fixed tooth plate

6-8‧‧‧Adjusting screw

6-9‧‧‧Fiber

6-10‧‧‧Fixed platform

1 is a side view of the clamping device of the embodiment of the present invention; FIG. 2 is a bottom view of the clamping device shown in FIG. 1 when the wafer is clamped; FIG. 3 is a drawing device of the clamping device shown in FIG. FIG. 4 is a schematic view showing a state in which a clamping device shown in FIG. 1 clamps a wafer and a wafer when clamping a wafer; FIG. 5 is a view using the clamp shown in FIG. Schematic diagram of a process for holding a semiconductor wafer; FIG. 6 is a schematic structural view of a fiber microbend sensor in the clamping device shown in FIG. 1; and FIG. 7 is an exemplary function of the fiber microbend sensor A graph of pressure versus time.

1-1‧‧‧Rotary axis

1-2‧‧‧ chuck

1-3‧‧‧ cam

1-4‧‧‧ bearing

1-5‧‧‧Clamping components

1-6‧‧‧Sensor

1-7‧‧‧Upper cover

1-8‧‧‧Under the cover

1-9‧‧‧Semiconductor wafer

1-10‧‧‧Compressed spring

A-A‧‧‧Rotary axis rotation center

B-B‧‧‧Clamping element rotation center

Claims (11)

A clamping device having a function of monitoring a state of a semiconductor wafer, comprising a rotatable chuck, a rotating shaft located at a geometric center of the chuck, a sensor fixed to the rotating shaft, and distributed on the chuck At least three clamping elements on the upper. A holding device as described in claim 1, wherein each of the clamping members is provided with a compression spring. The holding device of claim 1, wherein the chuck has at least two movable stops distributed thereon. The holding device of claim 1, wherein the holding device further comprises a cam rotatable relative to the chuck, one end of the clamping member being in contact with the cam. The holding device of claim 4, wherein a pulley or a bearing is disposed at a contact end of the clamping member with the cam. A clamping device as claimed in claim 4, wherein the cam is mounted to the chuck by a bearing. The clamping device of claim 4, wherein the cam is provided with at least two oblong holes. The holding device of claim 1, wherein the chuck is provided with a structure for restricting rotation of the clamping member relative to the chuck along an axis of the clamping member. The holding device of claim 7, wherein the clamping device further comprises a driving rod located in the oblong hole. The holding device according to any one of claims 1 to 9, wherein the sensor is a fiber microbend sensor. A method for monitoring the state of a semiconductor wafer, in the process of performing a clamping operation on a semiconductor wafer by using the clamping device according to any one of claims 1 to 10, detecting a displacement of the fiber output by the sensor The change, when it is determined that the magnitude of the change in the detected fiber displacement is within a predetermined threshold range, generates a signal indicating that the semiconductor wafer is in an expected state.