JP2018012166A - Polishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device which can polish a wafer so that a cross section shape of the wafer becomes a targeted cross section shape according to the cross section shape of the wafer in polishing.SOLUTION: A polishing device 10 includes: an upper surface plate 21; a lower surface plate 22; a sun gear 23; an internal gear 24; and a carrier plate 30. The carrier plate 30 is autorotated or revolved by the sun gear 23 and the internal gear 24, and both surfaces of a wafer W placed within a workpiece holding hole 30A of the carrier plate 30 are polished. The polishing device 10 includes: a shape measuring device 100 which measures a cross section shape of the wafer W in polishing; and a control device 300 which controls the polishing according to the cross section shape measured by the shape measuring device 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polishing apparatus that polishes the surface of a workpiece such as a silicon wafer.

  2. Description of the Related Art Conventionally, there is known a double-side polishing apparatus that polishes both sides of a wafer by rotating and revolving a carrier plate holding a wafer (see Patent Document 1).

  Such a double-side polishing apparatus includes a thickness measuring instrument capable of measuring the thickness of a wafer being polished, an upper surface plate having a through hole for measurement, a lower surface plate, a sun gear, an internal gear, a carrier plate, and the like. The carrier plate is sandwiched between the upper surface plate and the lower surface plate, and the carrier plate is engaged with the sun gear and the internal gear, and the carrier plate is rotated and revolved by rotating the sun gear and the internal gear. By rotating the plate and the lower surface plate, both surfaces of the wafer held by the carrier plate are polished.

  Further, the double-side polishing apparatus has a polishing step of polishing both surfaces of the wafer while only rotating the carrier plate, a measurement step of measuring the thickness at a predetermined position of the wafer during the polishing step, And a determination step of determining the polishing end time based on the measurement result.

JP 2015-47656 A

  However, in such a polishing apparatus, it is only necessary to determine the polishing end timing by measuring the thickness of the wafer at a predetermined position during the polishing process, so according to the cross-sectional shape of the wafer being polished, There is a problem that the wafer cannot be polished so as to have a target cross-sectional shape.

In the polishing process, it is required not only to finish the wafer to a desired thickness, but also to finish the wafer to a desired desired cross-sectional shape. The cross-sectional shape of a wafer is evaluated by an index such as SFQR or GBIR. By obtaining a wafer having a desired cross-sectional shape that satisfies the conditions of these indexes, a semiconductor device manufactured in a subsequent semiconductor device manufacturing process is obtained. Yield can be improved.
However, it is impossible to determine whether or not the cross-sectional shape of the wafer has been processed into a desired cross-sectional shape only by measuring the thickness of the wafer. Therefore, in order to obtain a wafer having a desired cross-sectional shape, the cross-sectional shape of the wafer is measured during polishing, and processing conditions are set so as to obtain a desired cross-sectional shape according to the measured cross-sectional shape of the wafer. There has been a demand for a polishing apparatus capable of polishing the substrate.

  In addition, the cross-sectional shape of the wafer is determined by the upper and lower surface plates, the lower surface plate, the rotation speed of the sun gear and the internal gear, the processing load, the supply amount and temperature of the polishing slurry, and the like. It changes depending on the state of the processing surface such as temperature change (shape change due to temperature change or wear), the actual temperature of the polishing slurry, and the processing state that changes as the polishing progresses, such as the rotation of the wafer. For this reason, even if the wafer is polished under the same processing conditions, the processing state is not always the same. That is, even if the wafer is polished under the same processing conditions, the processing state fluctuates, so that a wafer having a desired cross-sectional shape cannot be constantly obtained. Therefore, it is necessary to measure the cross-sectional shape of the wafer during the polishing process, and to change the processing conditions when the cross-sectional shape is not a desired one.

  Therefore, in order to obtain a wafer having a desired cross-sectional shape, the cross-sectional shape of the wafer is measured during the polishing process, and processing conditions are set so as to obtain a desired cross-sectional shape according to the measured cross-sectional shape of the wafer. There has been a demand for a polishing apparatus capable of polishing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing apparatus capable of measuring the cross-sectional shape of a wafer during polishing and polishing the wafer so as to obtain a target cross-sectional shape according to the measured cross-sectional shape of the wafer. Is to provide.

  The present invention is a polishing apparatus for polishing a workpiece by a polishing machine having a rotatable surface plate, a shape measuring device for measuring a cross-sectional shape of the workpiece during polishing, and a workpiece measured by the shape measuring device. And a control device for controlling polishing so that the cross-sectional shape becomes a target cross-sectional shape based on the cross-sectional shape.

  According to this invention, the cross-sectional shape of the workpiece can be measured during the polishing process, and the workpiece can be polished so as to have a target cross-sectional shape according to the measured cross-sectional shape of the workpiece. Therefore, it is possible to proceed with polishing while grasping whether or not the cross-sectional shape of the workpiece has been processed into the target cross-sectional shape. If the cross-sectional shape is not the target cross-sectional shape, the processing conditions can be changed during polishing. it can. As a result, it is possible to obtain a workpiece having a target cross-sectional shape on a regular basis.

It is explanatory drawing which showed the structure of the Example of the grinding | polishing apparatus based on this invention. It is explanatory drawing which showed the positional relationship of the sun gear shown in FIG. 1, an internal gear, and a carrier plate. It is explanatory drawing of the table which displayed the optimal recipe according to the result of having compared the cross-sectional shape of the measured wafer, and the cross-sectional shape of the target wafer. It is explanatory drawing of the table which displayed the process conditions of each recipe. It is explanatory drawing which showed the judgment shape and PV value based on the cross-sectional shape and cross-sectional shape of a wafer. It is a flowchart which shows operation | movement of 1st Example. It is a flowchart which shows the main process step process of FIG. It is a flowchart which shows operation | movement of 2nd Example.

Hereinafter, an example which is an embodiment of a polisher concerning this invention is described based on a drawing.
[First embodiment]

A polishing apparatus 10 shown in FIG. 1 includes a polishing machine 20 that polishes both surfaces of a wafer (silicon wafer) W that is one of workpieces, and a shape measuring apparatus 100 that measures a cross-sectional shape in the radial direction of the wafer W being polished. Based on the radial cross-sectional shape of the wafer W measured by the shape measuring device 100, a control device 300 for controlling driving devices M1 to M5 and the like which will be described later so that the cross-sectional shape becomes a target cross-sectional shape. And. Reference numeral 200 denotes a storage unit that stores a recipe indicating appropriate processing conditions for making the cross-sectional shape a target cross-sectional shape according to the cross-sectional shape in the radial direction of the wafer W.
[Polishing machine]

  The polishing machine 20 includes an upper surface plate 21 and a lower surface plate 22, a sun gear 23 rotatably disposed at the center of the upper surface plate 21 and the lower surface plate 22, and an outer peripheral side of the upper surface plate 21 and the lower surface plate 22. The internal gear 24 is disposed, and the carrier plate 30 is disposed between the upper surface plate 21 and the lower surface plate 22 and provided with a work holding hole 30A (see FIG. 2). A polishing member 25 is provided on the lower surface of the upper surface plate 21, and a polishing member 26 is provided on the upper surface of the lower surface plate 22.

  As shown in FIG. 2, the carrier plate 30 meshes with the sun gear 23 and the internal gear 24, and rotates and revolves as the sun gear 23 and the internal gear 24 rotate. Due to the rotation and revolution of the carrier plate 30, both surfaces of the wafer W disposed in the work holding hole 30 </ b> A of the carrier plate 30 are polished by the polishing members 25 and 26.

  As shown in FIG. 1, the upper surface plate 21 is fixed to a rod 42 via a support stud 40 and a mounting member 41. The rod 42 is moved up and down by the driving device M1, and the upper surface plate 21 is moved up and down integrally by the vertical movement of the rod 42.

  On the other hand, the upper portion 43A of the drive shaft 43 passes through the hole 23A in the center of the sun gear 23, and the sun gear 23 is fixed to the upper portion 43A, and the sun gear 23 rotates integrally with the drive shaft 43. It is like that. The drive shaft 43 is rotated by the drive device M4, and the sun gear 23 is rotated integrally with the drive shaft 43 by the drive device M4.

  A drive shaft 44 rotated by the drive device M <b> 2 is inserted into the hole of the drive shaft 43, and an upper end portion 44 </ b> A of the drive shaft 44 projects from the upper end of the drive shaft 43. A driver 45 is fixed to the upper end portion 44A, and the driver 45 rotates integrally with the drive shaft 44. A hook 46 provided on the upper surface plate 21 is engaged with the outer peripheral surface of the driver 45, and the upper surface plate 21 is rotated integrally with the rotation of the driver 45. Further, the hook 46 can move in the vertical direction with respect to the outer peripheral surface of the driver 45, and thus the upper surface plate 21 can move up and down with respect to the driver 45.

  That is, the upper surface plate 21 moves up and down by the vertical movement of the rod 42 and rotates by the rotation of the drive shaft 44. That is, the upper surface plate 21 is rotated integrally with the drive shaft 44 by the drive device M2.

  A drive shaft 49 is formed in the lower part of the center portion of the lower surface plate 22, and the drive shaft 43 is rotatably disposed in the drive shaft 49. The drive shaft 49 is rotated by the drive device M3, and the lower surface plate 22 is rotated integrally with the drive shaft 49 by the drive device M3.

  A drive shaft 47 is formed in the internal gear 24, and a drive shaft 49 is rotatably disposed in the drive shaft 47. The drive shaft 47 is rotated by the drive device M5, and the internal gear 24 is rotated integrally with the drive shaft 47 by the drive device M5.

A measurement hole 50 is formed in the upper surface plate 21 at a position spaced a predetermined distance in the radial direction from the center of the upper surface plate 21. The measurement hole 50 is formed through the upper surface plate 21 and the polishing member 25, and is fitted with a window member 51 that transmits infrared laser light as measurement light. The upper surface plate 21 is provided with a supply hole (not shown) for supplying polishing slurry.
[Shape measuring device]

As shown in FIG. 1, the shape measuring apparatus 100 irradiates the wafer W with infrared laser light as measurement light through a window member 51 mounted in the measurement hole 50 of the upper surface plate 21 and the wafer W. The optical head 101 that receives the reflected light reflected by the optical head 101, the laser oscillator 102 for irradiating the infrared laser light from the optical head 101, and the arithmetic unit 110 for obtaining the cross-sectional shape in the radial direction of the wafer W are provided. . The optical head 101 is provided on the upper surface plate 21 and rotates together with the upper surface plate 21.
[Calculator]

The computing device 110 includes a thickness computing unit 111 that obtains the measured thickness of the wafer W based on the reception of reflected light from the optical head 101, and sets the in-plane position from which the measured thickness of the wafer W is obtained to the sun gear 23 and the internal gear. The cross-sectional shape for obtaining the cross-sectional shape in the radial direction of the wafer W from the position calculation unit 112 obtained from the 24 rotational positions, the measured thickness of the wafer W obtained by the thickness calculation unit 111 and the in-plane position obtained by the position calculation unit 112 And an arithmetic unit 113.
[Thickness calculator]

The thickness calculation unit 111 measures, for example, by light reflection interferometry. Based on the reception of the reflected light of the optical head 101, the thickness calculation unit 111 calculates the reflection intensity on the surface of the wafer W of the wavelength tunable laser beam that sweeps the wavelength at high speed. The measured thickness of the wafer W is obtained by reconstructing the wavelength dispersion of reflection (state of interference of light reflected on the front and back surfaces of the wafer W) from this reflection intensity and analyzing the frequency.
[Position calculation unit]

The position calculation unit 112 obtains the position and rotation speed of the carrier plate 30 based on the rotation positions of the sun gear 23 and the internal gear 24. That is, the revolution position and the rotation position of the carrier plate 30 are obtained, and the in-plane position of the wafer W is obtained based on the revolution position and the rotation position. Thereby, the in-plane position where the measured thickness of the wafer W obtained by the thickness calculator 111 is measured is obtained.
[Cross-section shape calculation unit]

  The cross-sectional shape calculation unit 113 obtains the radial cross-sectional shape of the wafer W based on the measured thickness of the wafer W obtained by the thickness calculation unit 111 and the in-plane position of the wafer W obtained by the position calculation unit 112. Go.

The cross-sectional shape of the wafer W in the radial direction can be obtained by an arbitrary method. Here, for example, as shown in FIG. 5, when the diameter of the wafer W is 300 mm, the shape of the section of 0 to 150 mm (for the radius of the wafer W) is obtained, and the shape of this section is mirror-inverted around the point of 150 mm. Thus, the cross-sectional shape in the radial direction of the wafer W is obtained. Further, the shape of the section of 0 to 300 mm (for the diameter of the wafer W) can be obtained without reversing the mirror, and the sectional shape in the radial direction of the wafer W can be obtained. Next, the determination shape and PV value of the wafer W are obtained from the radial cross-sectional shape of the wafer W obtained. The “judgment shape” of the wafer W is a type classified based on the tendency of the cross-sectional shape in the radial direction of the wafer W. Of the obtained cross-sectional shape in the radial direction of the wafer W, the cross-sectional shape corresponding to the radius of the wafer W is divided into arbitrary sections. Based on the tendency of the cross-sectional shape of the divided sections, as shown in FIG. A corresponding type is selected from types obtained by combining inverted V-shaped, W-shaped, M-shaped, U-shaped, etc., and this type is used as the “judgment shape” of the wafer W. The PV value is a difference between the maximum measured thickness P and the minimum measured thickness V of the wafer W as shown in FIG. Note that the control device 300 may obtain the PV value.
[Control device]

The control device 300 compares the obtained cross-sectional shape in the radial direction of the wafer W with the target cross-sectional shape of the wafer W. That is, the determined shape and PV value of the wafer W is compared with the determined shape and PV value of the target wafer W, and a recipe corresponding to the comparison result is stored in the storage unit 200. 3 is read from the table 1 shown in FIG. 3, and the processing conditions corresponding to the read recipe are read from the table 2 shown in FIG. 4, and polishing such as control of driving of each of the driving devices M1 to M5 is performed based on the read processing conditions. Control processing. The control device 300 is also configured to control the arithmetic device 110.
[Storage unit]

  As shown in FIG. 3, the storage unit 200 stores a table 1 that displays an optimum recipe according to a result of comparing the obtained cross-sectional shape in the radial direction of the wafer W with a target cross-sectional shape. Yes.

  Further, the storage unit 200 stores a table 2 displaying the processing conditions of each recipe as shown in FIG.

  The machining conditions are the rotational speed of the upper surface plate 21 and the lower surface plate 22, the rotational speed of the sun gear 23 and the internal gear 24, the processing load and unit pressure of the upper surface plate 21, the load slope, and the acceleration of the upper surface plate 21 and the lower surface plate 22. These are the time, the deceleration time of the upper surface plate 21 and the lower surface plate 22, the rotational speed of rotation and revolution of the carrier plate 30, and the like.

The optimum processing condition is obtained in advance by experiment to determine a processing condition capable of polishing the obtained cross-sectional shape in the radial direction of the wafer W so as to efficiently achieve the target cross-sectional shape. The processing conditions may include the type of polishing slurry, the supply amount, the temperature, and the like. By changing these processing conditions during the polishing process, the polishing process can be controlled.
[Operation]

Next, operation | movement of the grinding | polishing apparatus 10 comprised as mentioned above is demonstrated based on the flowchart shown in FIGS.
In step S1, basic processing conditions are selected. The basic processing conditions refer to processing conditions serving as a base for performing polishing processing from the start of polishing processing of the wafer W until feedback processing based on measurement results described later is performed. First, the polishing process of the wafer W is started according to a basic processing condition that is a preset base.

  In step S2, the wafer W is loaded into the workpiece holding hole 30A (see FIG. 2) of the carrier plate 30. Then, the upper surface plate 21 in the retracted position is lowered, and the wafer W is sandwiched between the lower surface plate 22 and the upper surface plate 21.

In step S3, double-side polishing is started under basic processing conditions.
In step S4, an initial machining step operation is performed. That is, the upper surface plate 21 and the lower surface plate 22 are rotated at a low speed by the control of the driving devices M2 and M3 by the control device 300, and the upper surface plate 21 is pressed downward with a low load by the control of the driving device M1. Thereby, the upper surface plate 21 presses the wafer W with a low load. Further, the sun gear 23 and the internal gear 24 are rotated at a low speed by the control of the driving devices M4 and M5 by the control device 300, and the carrier plate 30 rotates and revolves at a low speed.

Both surfaces of the wafer W are polished by the low speed rotation of the upper surface plate 21 and the lower surface plate 22 and the low load of the upper surface plate 21. Further, both surfaces of the wafer W are polished by the rotation and revolution at a low speed of the carrier plate 30.
During the polishing period, the polishing slurry is supplied at a predetermined timing from a supply hole (not shown) provided in the upper surface plate 21.

When the processing operation in step S4 is performed for a predetermined time, the process proceeds to step S5.
In step S5, the upper surface plate 21 and the lower surface plate 22 that are rotated at a low speed are gradually rotated at a medium speed by gradually increasing the rotation speed. Further, the upper surface plate 21 is further pressed downward with a medium load. Thereby, the upper surface plate 21 presses the wafer W with a medium load. Further, the rotational speeds of the sun gear 23 and the internal gear 24 that are rotated at a low speed are gradually increased to be rotated at a medium speed, and the carrier plate 30 rotates and revolves at a medium speed. Then, both surfaces of the wafer W are polished by the medium speed rotation of the upper surface plate 21 and the lower surface plate 22 and the medium load of the upper surface plate 21. Further, both surfaces of the wafer W are polished by the rotation and revolution at the medium speed of the carrier plate 30. Then, when the processing operation of step S5 is performed for a predetermined time as in step S4, the process proceeds to step S20.

  Step S20 performs a main machining step process, and this main machining step process is performed by the processing operation of steps S21 to S26, that is, a feedback process, as shown in FIG. Hereinafter, the processing operations of steps S21 to S26 will be described.

  In step S21, the upper surface plate 21 and the lower surface plate 22 rotated at medium speed are gradually rotated at a high speed with the rotational speed gradually increased. Further, the upper surface plate 21 is pressed downward with a high load. Thereby, the upper surface plate 21 presses the wafer W with a high load. Further, the rotational speeds of the sun gear 23 and the internal gear 24 that are rotating at medium speed are gradually increased and rotated at high speed, and the carrier plate 30 rotates and revolves at high speed. Then, both surfaces of the wafer W are polished by the high-speed rotation of the upper surface plate 21 and the lower surface plate 22 and the high load of the upper surface plate 21. Further, both surfaces of the wafer W are polished by the high speed rotation and revolution of the carrier plate 30.

  On the other hand, infrared laser light is irradiated downward from the optical head 101 by the laser oscillator 102, and the wafer W is irradiated through the window member 51 of the measurement hole 50, and reflected light reflected by the front and back surfaces of the wafer W is reflected. The light enters the optical head 101 through the window member 51 of the measurement hole 50.

  In step S22, every time the optical head 101 receives reflected light, the thickness calculation unit 111 obtains the measured thickness of the wafer W based on the received interference light between the reflected light on the front surface and the back surface of the wafer W. . On the other hand, the position calculation unit 112 of the calculation device 110 calculates the in-plane position of the wafer W from which the measured thickness is calculated.

  The cross-sectional shape calculation unit 113 of the calculation device 110 is based on each measured thickness of the wafer W obtained by the thickness calculation unit 111 and each in-plane position of the wafer W from which the measured thickness is obtained. The cross-sectional shape in the radial direction of W is obtained. That is, the radial cross-sectional shape of the wafer W is obtained from the measured thickness at each in-plane position of the wafer W. Further, the PV value is obtained based on the obtained radial cross-sectional shape of the wafer W. Further, the thickness of the wafer W is obtained based on the measured thickness of the wafer W obtained. Here, the “measured thickness of the wafer W” refers to each measured thickness, and a plurality of data are used for drawing a cross-sectional shape. “Wafer W thickness” refers to the representative value (moving average value, etc.) of the current wafer thickness measured based on the measured thickness of the wafer W. The number of data is single. Used for comparison with target thickness.

  That is, in step S22, the cross-sectional shape of the wafer W in the radial direction, the PV value shown in FIG. 5, the thickness of the wafer W, and the like are obtained in real time during the double-side polishing of the wafer W.

  In step S221, the obtained sectional shape in the radial direction of the wafer W is compared with a predetermined reference shape to determine which judgment shape corresponds to the obtained sectional shape in the radial direction of the wafer W. decide. That is, the cross-sectional shape for the radius of the obtained wafer W is divided into arbitrary sections, for example, the outer periphery of the wafer W, the inner periphery, the intermediate periphery between the outer periphery and the inner periphery, etc. Based on the tendency of the cross-sectional shape in these divided sections, as shown in FIG. 5, the corresponding type from the combination of unevenness and inverted V-shaped, W-shaped, M-shaped, U-shaped, etc. And decide.

  In step S23, it is determined whether or not the radial cross-sectional shape of the wafer W obtained in steps S22 and S221 has reached the target cross-sectional shape. That is, it is determined whether or not the determination shape of the wafer W obtained in step S22 and step S221 has reached the target determination shape and the PV value has reached the target PV value. Proceed to S24.

In step S24, it is determined whether or not the thickness of the wafer W obtained in step S22 is less than or equal to the lower limit of the target thickness. If the wafer W is less than or equal to the lower limit of the target thickness, the wafer W may be damaged. In S24, it is determined as YES, and the process proceeds to step S6, and the process proceeds to the process step of finishing the polishing process.
If the thickness of the wafer W is not less than or equal to the lower limit of the target thickness, it is determined NO in step S24 and the process proceeds to step S25.

  In step S25, the control device 300 compares the radial cross-sectional shape of the wafer W obtained in steps S22 and S221 with the target cross-sectional shape of the wafer W, and stores a recipe based on the comparison result. Read from the table 1 (see FIG. 3) stored in the unit 200, read the processing conditions indicated by the read recipe from the table 2 (see FIG. 4), and based on the read processing conditions, each of the driving devices M1 to M5. Control the drive of the. Then, the process returns to step S22.

  In step S22, the cross-sectional shape of the wafer W in the radial direction, that is, the determination shape of the wafer W, the PV value, and the like are obtained again as described above. Until the cross-sectional shape in the radial direction of the obtained wafer W reaches the target cross-sectional shape, the processing operations of Step S22 to Step S25 are repeated, and both surfaces of the wafer W are polished, and the radial direction of the wafer W Since the processing conditions (recipe) are also changed according to the cross-sectional shape of the wafer W, it is possible to reliably polish the radial cross-sectional shape of the wafer W so as to become the target cross-sectional shape.

When the radial cross-sectional shape of the wafer W reaches the target cross-sectional shape, it is determined as YES in step S23, and the process proceeds to step S26.
In step S26, it is determined whether or not the thickness of the wafer W is equal to or less than the upper limit of the target thickness. If no, the process returns to step S21, and steps S21 to S21 are performed until the thickness of the wafer W is equal to or less than the upper limit of the target thickness. The processing operation in step S26 is repeated. If the thickness of the wafer W is less than or equal to the upper limit of the target thickness, it is determined as YES and the process proceeds to step S6.

  In step S6, a deceleration processing step operation is performed. That is, the upper surface plate 21, the lower surface plate 22, the sun gear 23, and the internal gear 24 that are rotated at high speed by the control of the driving devices M1 to M5 by the control device 300 are decelerated and rotated at medium speed, and the upper surface plate 21 is rotated. The downward load is reduced to a medium load. When the processing operation in step S6 is performed for a predetermined time, the process proceeds to step S7.

  In step S7, a pure water cleaning step operation is performed. That is, pure water is supplied from the supply hole provided in the upper surface plate 21, and the upper surface plate 21, the lower surface plate 22, the sun gear 23, and the internal gear 24 are decelerated and rotated at a low speed. Moreover, the downward load by the upper surface plate 21 is reduced to a low load. Then, both surfaces of the wafer W are cleaned with pure water. When the processing operation in step S7 is performed for a predetermined time, the process proceeds to step S8, and the machining operation is terminated.

  In step S9, the upper surface plate 21 is raised to recover the polished wafer W, and in step S10, the cross-sectional shape of the wafer W is measured by an external measuring instrument.

  As described above, the cross-sectional shape of the wafer W is measured during polishing, and the processing conditions (recipe) are changed so that this cross-sectional shape becomes the target cross-sectional shape. Polishing to the target cross-sectional shape can be performed. Further, as described above, since the comparison with the target thickness can be performed in step S24, it is possible to reliably prevent the generation of defective products due to excessive polishing of the wafer W.

Furthermore, since the cross-sectional shape of the wafer W is measured and the processing conditions are changed according to the cross-sectional shape, it is possible to prevent only a part of the wafer W from becoming too thin or too thick. . Furthermore, during the polishing process, the polishing process can proceed while grasping whether the cross-sectional shape of the wafer W is processed into the target cross-sectional shape. If the cross-sectional shape is not the target cross-sectional shape, the processing conditions are changed during the polishing process. Therefore, the wafer W having a target cross-sectional shape can be obtained constantly.
[Second Embodiment]

  FIG. 8 shows a flowchart of the second embodiment. In the second embodiment, step S20 ′ for performing the main machining step process 1 and step S30 for performing the main machining step process 2 are provided after step S5.

  The main machining step process 1 in step S20 ′ is performed in steps S21 to S26 shown in FIG. 7, but the “target cross section shape arrival” in step S23 is changed to “first target cross section shape arrival”. . The first target cross-sectional shape indicates a cross-sectional shape at a stage before reaching the target cross-sectional shape. Others are the same as in the first embodiment, and a description thereof will be omitted.

  The main processing step process 2 in step S30 performs the same processing operation as that in steps S21 to S26 shown in FIG.

  According to the second embodiment, since the steps S20 ′ and S30 are provided, the wafer W can be polished into a target cross-sectional shape in a plurality of stages. Thus, it can be polished more reliably. That is, it is possible to more reliably prevent generation of defective products due to excessive polishing of the wafer W, and it is possible to reliably prevent only a part of the wafer W from becoming too thin or too thick. . Furthermore, during the polishing process, the polishing process can proceed while grasping whether the cross-sectional shape of the wafer W is processed into the target cross-sectional shape. If the cross-sectional shape is not the target cross-sectional shape, the processing conditions are changed during the polishing process. Therefore, the wafer W having a target cross-sectional shape can be obtained constantly.

  In the above embodiment, the upper surface plate 21 is provided with the measurement hole 50. However, the lower surface plate 22 is provided with the measurement hole, and the lower surface of the wafer W is irradiated with infrared laser light from below to change the cross-sectional shape of the wafer W. You may make it measure.

  Moreover, although the case where 1 wafer W was grind | polished using one carrier plate 30 was demonstrated, the several wafer W is arrange | positioned between the upper surface plate 21 and the lower surface plate 22, and several wafer W is arrange | positioned. The present invention can also be applied to the case where polishing is performed simultaneously or a plurality of wafers W are arranged on one carrier plate.

  Further, in the above embodiment, the optical head 101 is provided on the upper surface plate 21, but the optical head is provided above a position spaced from the center of the upper surface plate 21 in the radial direction by a predetermined distance. Each time the measurement hole 50 comes under the optical head by rotation, the infrared laser light emitted from the optical head irradiates the wafer W through the window member 51, and the cross-sectional shape of the wafer W may be measured. . At least one measuring hole 50 may be provided, but a plurality of measuring holes 50 may be formed at equal intervals along the circumferential direction of the positions separated by the predetermined distance. When a plurality of measurement holes 50 are formed, a window member 51 is attached to each measurement hole 50.

  In the above embodiments, the polishing apparatus for polishing both surfaces of the wafer W has been described. However, the present invention can also be applied to a polishing apparatus for polishing only one surface of the wafer W.

  In the above-described embodiment, the processing operations of Steps S21 to S26 are performed at Steps S20, S20 ′, and S30. However, the present invention is not limited to this. A processing operation similar to S26 may be performed. Moreover, although the said Example demonstrated the case where a silicon wafer was grind | polished, it is not restricted to this, What is necessary is just thin plate-like workpieces, such as glass, ceramics, and quartz.

  The present invention is not limited to the above-described embodiments, and design changes and additions are permitted without departing from the spirit of the invention according to each claim of the claims.

10 Polishing device 20 Polishing machine 21 Upper surface plate (surface plate)
22 Lower surface plate (surface plate)
DESCRIPTION OF SYMBOLS 50 Measurement hole 100 Shape measuring apparatus 101 Optical head 111 Thickness calculating part 112 Position calculating part 113 Section shape calculating part 200 Memory | storage part 300 Control apparatus W Wafer (workpiece)

Claims (3)

A polishing apparatus for polishing a workpiece by a polishing machine having a rotatable surface plate,
A shape measuring device for measuring the cross-sectional shape of the workpiece during polishing;
A polishing apparatus comprising: a control device that controls polishing processing so that the cross-sectional shape becomes a target cross-sectional shape based on the cross-sectional shape of the workpiece measured by the shape measuring device. According to the cross-sectional shape of the workpiece, comprising a storage unit that stores a recipe indicating an appropriate processing condition for a target cross-sectional shape,
The said control apparatus reads a recipe from the said memory | storage part according to the cross-sectional shape of the workpiece | work measured by the said shape measuring apparatus, and controls grinding | polishing processing based on the processing conditions of this read recipe. Item 2. The polishing apparatus according to Item 1. The shape measuring device is an optical head that receives the reflected light reflected by the workpiece while being irradiated with the measuring beam through the measurement hole provided in the surface plate,
A thickness calculating device for obtaining a measured thickness of the workpiece based on reception of reflected light of the optical head;
A position calculation device for obtaining an in-plane position from which the measured thickness of the workpiece is obtained;
The cross-sectional shape computing device for obtaining a cross-sectional shape of the workpiece based on the measured thickness of the workpiece obtained by the thickness computing device and the in-plane position obtained by the position computing device. The polishing apparatus according to claim 1 or 2.