WO2017026603A1

WO2017026603A1 - Wafer polishing device and method for operating same

Info

Publication number: WO2017026603A1
Application number: PCT/KR2016/000079
Authority: WO
Inventors: 한기윤; 배재현
Original assignee: 주식회사 엘지실트론
Priority date: 2015-08-13
Filing date: 2016-01-06
Publication date: 2017-02-16

Abstract

An embodiment of a wafer polishing device may comprise: a donut-shaped upper surface plate; a lower surface plate, which is formed in a donut shape, and which is arranged on the lower portion of the upper surface plate; a first polishing pad, which is attached to the lower surface of the upper surface plate, and which polishes a surface of a wafer; a second polishing pad, which is attached to the upper surface of the lower surface plate, and which polishes a different surface of the wafer; and a plurality of sensors arranged in the diameter direction of the upper surface plate, and which measure the amount of deformation of the lower surface of the first polishing pad and the upper surface of the second polishing pad or the amount of wear thereof.

Description

Wafer Polishing Machine and Its Operation Method

An embodiment relates to a wafer polishing apparatus and a method of operating the same.

The content described in this section merely provides background information on the embodiments and does not constitute a prior art.

In recent years, high integration of semiconductors has resulted in an increase in processing and storage capacity of information per unit area, which requires large diameters of semiconductor wafers, miniaturization of circuit line widths, and multilayer wiring. In order to form a multilayer wiring on a semiconductor wafer, high flatness of the wafer is required, and a wafer planarization process is required for such high flatness.

One of the wafer planarization processes is a wafer polishing process. A wafer polishing process is a process of polishing the upper and lower surfaces of a wafer with a polishing pad.

However, as the wafer polishing process is continuously and repeatedly performed, wear of the polishing pad and performance degradation may occur. If the polishing pad is worn or the performance decreases, the wafer may be damaged during the polishing process.

Therefore, it is necessary to periodically polish or replace the polishing pad. Whether to polish or replace the polishing pad can be known by first understanding the surface state of the polishing pad, in particular, the amount of deformation and wear of the polishing pad.

Therefore, development of a wafer polishing apparatus capable of accurately measuring the amount of deformation and wear of the polishing pad is required. In addition, there is a need to develop a method of operating a wafer polishing apparatus that can prevent or significantly reduce wafer damage based on the measured amount of deformation and wear of the polishing pad.

Accordingly, the embodiment relates to a wafer polishing apparatus and a method of operating the wafer polishing apparatus capable of precisely measuring the amount of deformation and abrasion of the polishing pad and preventing or significantly reducing the damage of the wafer based on the measured amount of deformation and the amount of wear of the polishing pad. will be.

Embodiments of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above may be clearly understood by those skilled in the art to which the embodiments belong.

One embodiment of the wafer polishing apparatus includes a donut shaped top plate; A lower plate formed in a donut shape and disposed below the upper plate; A first polishing pad attached to a lower surface of the upper surface plate and polishing one surface of the wafer; A second polishing pad attached to an upper surface of the lower plate and polishing the other surface of the wafer; And a plurality of arranged in the radial direction of the upper surface plate, and may include a sensor for measuring the amount of deformation or wear of the lower surface of the first polishing pad and the upper surface of the second polishing pad.

A driving unit may be disposed between the first polishing pad and the second polishing pad to rotate and revolve the wafer.

The drive unit, a drive shaft; A tooth gear is formed on an outer circumferential surface, the sun gear coupled to the drive shaft to rotate about the drive shaft in accordance with the rotation of the drive shaft; A ring gear disposed around the drive shaft, spaced apart from the sun gear in a radial direction, and having a tooth formed on an inner circumferential surface thereof; And a tooth formed on an outer circumferential surface, meshed with the sun gear and the ring gear, and a carrier on which the wafer is mounted.

As the drive shaft rotates, the carrier may rotate while rotating about the drive shaft.

The sensor may measure a deformation amount of the first polishing pad and the second polishing pad by measuring a distance from the carrier.

The sensor may measure the amount of wear of the first polishing pad and the second polishing pad by measuring a distance between the upper and lower plates.

The sensor may be an eddy current sensor.

One embodiment of the wafer polishing apparatus may be provided on the upper surface plate, and further include a measurement unit for measuring the thickness of the wafer.

An embodiment of the wafer polishing apparatus may further include an operation unit electrically connected to the sensor and configured to quantify the amount of deformation or wear of the first polishing pad and the second polishing pad.

An embodiment of the wafer polishing apparatus may further include a controller electrically connected to the computing unit and controlling a polishing process of the wafer.

One embodiment of a method of operating a wafer polishing apparatus includes: measuring a deformation amount of a lower surface of a first polishing pad and an upper surface of a second polishing pad through a plurality of sensors provided in an upper surface plate; A deformation amount calculating step of quantifying a deformation amount of the lower surface of the first polishing pad and the upper surface of the second polishing pad in a calculation unit electrically connected to the plurality of sensors; A comparison step of comparing the numerical value of the deformation amount with a preset set value; And a dressing step of dressing a lower surface of the first polishing pad and an upper surface of the second polishing pad when the amount of deformation quantified exceeds the set value.

In the comparing step, it may be to compare the maximum value and the set value of the plurality of numerical values of the deformation amount.

In the comparing step, when the numerical value of the deformation exceeds the set value, the controller for controlling the polishing process of the wafer may transmit a warning sound or a warning message.

The set value may be 1.5 μm to 10 μm.

The set value may be one of 3μm to 5μm.

Another embodiment of a method of operating a wafer polishing apparatus includes: measuring abrasion amount of a lower surface of a first polishing pad and an upper surface of a second polishing pad through a plurality of sensors provided in an upper surface plate; A determination step of determining whether the measured amount of wear exceeds a predetermined set value; A pad operating time adjusting step of adjusting an operating time of the first polishing pad and the second polishing pad according to the measured wear amount when the measured wear amount is less than the set value; And a pad replacement step of replacing the first polishing pad or the second polishing pad when the measured wear amount exceeds the set value.

The wear amount may be measured by comparing the thickness in a state where the lower surface of the first polishing pad and the upper surface of the second polishing pad are not worn and a thickness in a worn state after the polishing process of the wafer is performed.

The calculation unit electrically connected to the plurality of sensors may quantify the amount of wear on the lower surface of the first polishing pad and the upper surface of the second polishing pad.

In the pad operating time adjusting step, the pad operating time may be adjusted by a controller that controls the polishing process of the wafer.

The set value may be 10% to 20% of the sum of the thicknesses of the first polishing pad and the second polishing pad that are not worn.

In an embodiment, the sensor can accurately measure the amount of deformation or wear of the polishing pad of the wafer polishing apparatus.

Therefore, it is possible to easily determine whether the polishing pad is dressing based on the measured deformation amount. In addition, the operating time of the polishing pad can be easily adjusted or the polishing pad can be easily determined based on the measured amount of wear.

Therefore, the wafer polishing apparatus of the embodiment and its operation method can prevent or significantly reduce the damage of the wafer in the wafer polishing process, and the work time can be shortened.

1 is a view showing a wafer polishing apparatus according to an embodiment.

FIG. 2 is a diagram for describing a method in which a sensor measures deformation amounts of a first polishing pad and a second polishing pad, according to an exemplary embodiment.

3 and 4 are views illustrating a method in which a sensor measures the amount of wear of the first polishing pad and the second polishing pad, according to an exemplary embodiment.

5 is a flowchart illustrating a method of operating a wafer polishing apparatus according to an embodiment.

6 is a flowchart illustrating a method of operating a wafer polishing apparatus according to another embodiment.

7 is a graph showing a relationship between the amount of wear of the first polishing pad and the second polishing pad and their operating time according to an embodiment.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. The embodiments may be modified in various ways and may have various forms. Specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the embodiments to the specific forms disclosed, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the embodiments. In this process, the size or shape of the components shown in the drawings may be exaggerated for clarity and convenience of description.

Terms such as "first" and "second" may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. In addition, terms that are specifically defined in consideration of the configuration and operation of the embodiments are only intended to describe the embodiments, and do not limit the scope of the embodiments.

In the description of the embodiments, when described as being formed at "on" or "on" or "under" of each element, it is on or under. ) Includes both elements in direct contact with each other or one or more other elements formed indirectly between the two elements. In addition, when expressed as "up" or "on (under)", it may include the meaning of the downward direction as well as the upward direction based on one element.

Furthermore, the relational terms such as "upper / top / up" and "bottom / bottom / bottom", etc., used below do not necessarily require or imply any physical or logical relationship or order between such entities or elements, It may be used only to distinguish one entity or element from another entity or element. In addition, in the drawing, a rectangular coordinate system (x, y, z) can be used.

1 is a view illustrating a wafer 10 polishing apparatus according to an embodiment. The wafer 10 polishing apparatus of the embodiment includes an upper plate 100, a lower plate 200, a first polishing pad 300, a second polishing pad 400, a sensor 500, a driving unit 600, and a measuring unit ( 700, a calculator 800, and a controller 900.

The upper plate 100 is formed in a donut shape having a hollow in a central portion, and the driving shaft 610 is coupled to the hollow, and when the driving shaft 610 rotates, the upper plate 100 is also rotated accordingly. Can be.

The lower plate 200 may be formed in a donut shape having a hollow in a central portion thereof, and may be disposed below the upper plate 100. The lower plate 200 may be coupled to the driving shaft 610, and when the driving shaft 610 rotates, the lower plate 200 may also be rotated accordingly.

Under the control of the polishing apparatus of the wafer 10, when the driving shaft 610 rotates, the upper plate 100 and the lower plate 200 may rotate in the same direction or may rotate in opposite directions. At this time, in order to increase the polishing efficiency of the wafer 10, it is appropriate to rotate the upper plate 100 and the lower plate 200 in opposite directions to polish the wafer 10.

The first polishing pad 300 may be attached to the lower surface of the upper surface plate 100 and polish one surface of the wafer 10. That is, the lower surface of the first polishing pad 300 is in contact with the upper surface of the wafer 10 mounted on the carrier 640, and rotates together as the upper surface plate 100 rotates, thereby rotating the wafer 10. The upper surface of can be polished.

The second polishing pad 400 may be attached to the upper surface of the lower surface plate 200 and polish the other surface of the wafer 10. That is, the upper surface of the second polishing pad 400 contacts the lower surface of the wafer 10 mounted on the carrier 640, and rotates together as the lower plate 200 rotates to lower the lower surface of the wafer 10. It can be polished.

In this case, the first polishing pad 300 and the second polishing pad 400 may be formed of a material capable of finely polishing both surfaces of the wafer 10, and may be formed of, for example, a nonwoven fabric.

Sensor 500 is arranged in a plurality in the radial direction of the upper surface plate 100, and serves to measure the amount of deformation or wear of the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400. can do.

The sensor 500 is a current passing through the first polishing pad 300 or the second polishing pad 400 in order to measure the amount of deformation and wear of the first polishing pad 300 and the second polishing pad 400. It is appropriate to be able to generate the light, etc., for example, it may be appropriate to be provided with an eddy current sensor.

For example, as illustrated in FIG. 1, the plurality of sensors 500 may include a first sensor 510, a second sensor 520, and a third sensor 530. However, this is only an example, and the number of the sensors 500 may be selected as an appropriate number in consideration of the size of the upper surface plate 100, the precision of the measurement, and the like.

In an embodiment, the first sensor 510 is disposed adjacent to the inner circumferential surface of the upper plate 100, and the third sensor 530 is disposed adjacent to the outer circumferential surface of the upper plate 100, and the second sensor ( 520 may be disposed between the first sensor 510 and the third sensor 530.

Since the sensors 500 are disposed on the upper surface plate 100 in the radial direction thereof, the deformation amount or wear amount of each portion of the first polishing pad 300 and the second polishing pad 400 is measured in the radial direction thereof. The total deformation amount or wear amount of the first polishing pad 300 and the second polishing pad 400 may be measured.

A method of measuring the deformation amount or wear amount of the first polishing pad 300 and the second polishing pad 400 using the sensor 500 will be described in detail with reference to FIGS. 2 to 4.

The driving unit 600 may be disposed between the first polishing pad 300 and the second polishing pad 400, and may serve to rotate and revolve the wafer 10. The driving unit 600 may include a driving shaft 610, a sun gear 620, a sun gear 630, and a carrier 640.

The drive shaft 610 may rotate by receiving power from an external power generator (not shown). In addition, since the drive shaft 610 is coupled to the upper plate 100 and the lower plate 200, as the drive shaft 610 rotates the upper plate 100 and the first polishing pad 300 attached thereto, The lower plate 200 and the second polishing pad 400 attached thereto may rotate about the driving shaft 610.

The sun gear 620 may have a tooth formed on an outer circumferential surface thereof, and may be coupled to the driving shaft 610 to rotate about the driving shaft 610 according to the rotation of the driving shaft 610. In this case, the teeth formed on the outer circumferential surface of the sun gear 620 may be meshed with the teeth formed on the outer circumferential surface of the carrier 640.

The ring gear 630 may be formed in a ring shape as a whole. The ring gear 630 may be disposed around the driving shaft 610, and may be spaced apart from the sun gear 620 in a radial direction, and a tooth may be formed on an inner circumferential surface thereof. In this case, the teeth formed on the inner circumferential surface of the ring gear 630 may be meshed with the teeth formed on the outer circumferential surface of the carrier 640.

The carrier 640 may have a tooth formed on an outer circumferential surface thereof and may be engaged with the sun gear 620 and the ring gear 630. In this case, since the sun gear 620 is provided to rotate and the ring gear 630 does not rotate, as the sun gear 620 rotates, the sun gear 620 rotates about its rotation axis and rotates about its own axis.

At this time, only one carrier 640 is shown in FIG. 1, but this is only an example. In order to simultaneously polish the plurality of wafers 10, the plurality of carriers 640 are disposed radially about the rotation axis. Can be.

Meanwhile, a wafer 10 may be mounted on the carrier 640, and a wafer hole 641 may be formed in the carrier 640 to mount the wafer 10. In addition, a slurry hole 642 may be formed in the carrier 640. The slurry holes 642 may be provided in plural in the carrier 640, and may have various diameters.

The slurry hole 642 may serve as a passage through which particles, slurry, and the like, which are polished and separated from the wafer 10 in the process of polishing the wafer 10, exit the lower portion of the carrier 640.

In addition, as shown in FIG. 1, the center of the wafer hole 641 may be spaced apart from the center of the carrier 640. This is to allow the wafer 10 mounted in the wafer hole 641 to revolve around the center of the carrier 640 when the carrier 640 rotates.

Accordingly, as the carrier 640 rotates and revolves, the wafer 10 mounted on the carrier 640 may revolve about the rotation axis and revolve around the center of the carrier 640. Since the wafer 10 is provided to revolve in duplicate, it can be polished very effectively.

The measuring unit 700 may be provided in the upper surface plate 100 and may serve to measure the thickness of the wafer 10. In this case, the measurement unit 700 may use, for example, a capacitive, optical or laser sensing device.

The calculation unit 800 is electrically connected to the sensor 500 and receives a signal from the sensor 500 so as to deform or wear the first polishing pad 300 and the second polishing pad 400 from the signal. It can serve to quantify.

In this case, when the sensor 500 is, for example, an eddy current sensor, the signal received by the operation unit 800 from the sensor 500 may be a signal for a change amount of the eddy current detected by the sensor 500.

The control unit 900 may be electrically connected to the operation unit 800 and may control a polishing process of the wafer 10. Accordingly, the controller 900 may control the entire wafer 10 polishing process by operating the polishing apparatus of the wafer 10 to proceed with the polishing of the wafer 10, or by stopping the polishing of the wafer 10.

Thus, although not shown in FIG. 1, when the controller 900 is required to control the wafer 10 polishing process, the controller 900 is electrically connected to the measurement unit 700 to allow the wafer 10 to be moved from the measurement unit 700. A signal for thickness may be received.

In addition, as will be described later, the control unit 900 may serve to send a warning sound or a warning message when the deformation amount of the first polishing pad 300 and the second polishing pad 400 exceeds a set value. In addition, the controller 900 adjusts the operating time of the first polishing pad 300 and the second polishing pad 400 according to the wear amount of the first polishing pad 300 and the second polishing pad 400. It can also play a role.

2 is a diagram illustrating a method of measuring the deformation amount of the first polishing pad 300 and the second polishing pad 400 by the sensor 500 according to an exemplary embodiment. However, for clarity, the deformed portions and shapes of the first polishing pad 300 and the second polishing pad 400 are exaggerated somewhat.

As the polishing of the wafer 10 proceeds, the first polishing pad 300 and the second polishing pad 400 may be deformed. In particular, deformation may occur on the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 which are in direct contact with the upper surface and the lower surface of the wafer 10.

For example, foreign matter sticking phenomenon in which foreign matters such as particles, slurry, and the like, which are polished by the polishing pad and separated from the wafer 10 are fixed to the polishing pad, and the polishing pad polishes the wafer 10 as the polishing pad polishes the wafer 10. In the case of hardening of the pad, the polishing pad formed of the nonwoven fabric may be deformed on the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 due to the lining of the nonwoven fabric lying in one direction. have.

Due to the deformation of the polishing pad, a curved surface may be formed at a specific portion of the polishing pad instead of forming an overall flat surface of the contact surface contacting the wafer 10.

When the curved surface formed as described above contacts the upper or lower surface of the wafer 10 to continuously polish the wafer 10, particles, slurry, etc., which are separated from the wafer 10, adhere to the recessed portion of the curved surface. And may accumulate. In addition, the wafer 10 may be excessively polished at the protruding portion of the curved surface.

When the polishing by the polishing pad is continuously performed in this state, a curved surface similar to the curved surface of the polishing pad may be formed on the upper or lower surface of the wafer 10. If the curved surface is formed on the wafer 10, this means that the defect of the wafer 10 occurs.

Therefore, in order to prevent or reduce the occurrence of curved surfaces on the wafer 10, the operation of removing the deformation portion of the polishing pad is performed, which is called dressing. Dressing operations are often referred to as diamond dressings because they are carried out using diamond-attached plates.

In other words, the dressing refers to operations such as removing foreign matter adhered to the polishing pad, softening the hardened portion of the polishing pad, and erecting the lint of the polishing pad lying in one direction in the case of the polishing pad formed of a nonwoven fabric. The dressing operation can be carried out in such a manner as to rub the deformed portion of the polishing pad using, for example, a diamond-attached plate.

When the dressing operation is performed, first, the amount of deformation of the first polishing pad 300 and the second polishing pad 400 must be measured, and the measurement can be performed using the sensor 500. In this case, the sensor 500 may measure the deformation distance between the first polishing pad 300 and the second polishing pad 400 by measuring a distance from the carrier 640.

The thickness of the carrier 640 is so thin that it is thinner than the thickness of the wafer 10. Therefore, as shown in FIG. 2, when the first polishing pad 300 and the second polishing pad 400 are deformed, the carrier 640 may also be deformed in a shape corresponding thereto. Therefore, the sensor 500 may measure the deformation amount of the first polishing pad 300 and the second polishing pad 400 by measuring the distance from the lower end of the upper plate 100 to the upper surface of the carrier 640.

As shown in FIG. 2, the distances from the lower end of the upper surface plate 100 measured by the first sensor 510, the second sensor 520, and the third sensor 530 to the upper surface of the carrier 640 are L1 and L2, respectively. And L3. Therefore, the plurality of sensors 500 may measure the deformation amount along the radial direction of the first polishing pad 300 and the second polishing pad 400.

In FIG. 2, for example, when the second polishing pad 400 is not deformed, the distance from the lower surface of the upper surface plate 100 to the upper surface of the carrier 640 may be known in advance, and thus may be used as a comparison reference value.

When the difference between the comparison reference value and L1, L2, and L3 is obtained, the deformation amounts at each part of the second polishing pad 400 can be obtained, and the maximum value of the deformation amounts is the reference value of the second polishing pad 400. The amount of deformation can be determined. In this case, the reference deformation amount may be used as a deformation amount to be compared with a set value when determining whether or not dressing.

On the other hand, in Figure 2 is shown a carrier 640 in close contact with the upper surface of the second polishing pad 400, in this case it is possible to measure the deformation amount of the second polishing pad 400. However, this is only one embodiment, and as another example, the carrier 640 may be in close contact with the bottom surface of the first polishing pad, and in this case, the deformation amount of the first polishing pad 300 may be measured. Therefore, in the embodiment, the sensor 500 may measure both the deformation amount of the first polishing pad 300 and the deformation amount of the second polishing pad 400.

The dressing may be determined according to the deformation amounts of the first polishing pad 300 and the second polishing pad 400, and a dressing operation may be performed. A detailed description thereof will be described below with reference to FIG. 5.

3 and 4 are views illustrating a method in which the sensor 500 measures the amount of wear of the first polishing pad 300 and the second polishing pad 400, according to an exemplary embodiment. The sensor 500 may measure the wear amount of the first polishing pad 300 and the second polishing pad 400 by measuring a distance between the upper surface plate 100 and the lower surface plate 200.

That is, the sensor 500 measures the distance from the upper end of the first polishing pad 300 to the lower end of the second polishing pad 400 so that the amount of wear of the first polishing pad 300 and the second polishing pad 400 is reduced. Can be measured. Specific measurement methods are as follows.

First, as shown in FIG. 3, the carrier 640 is removed from the wafer 10 polishing apparatus and the unused, i.e., unworn, first polishing pad 300 and second polishing pad 400 are closely attached to each other. Let's do it. Next, the distance from the top of the first polishing pad 300 to the bottom of the second polishing pad 400 using the sensor 500, that is, the thickness of the first polishing pad 300 and the second polishing pad 400. Measure the total thickness.

In this case, the total thickness may be measured as H1, H2, and H3 in the first sensor 510, the second sensor 520, and the third sensor 530, respectively. Since some errors may occur in H1, H2, and H3, the average value of H1, H2, and H3 can be set as the reference total thickness.

Next, as shown in FIG. 4, after the polishing process, the carrier 640 is removed from the polishing apparatus of the wafer 10 and used, that is, the worn first polishing pad 300 and the second polishing pad are used. Close the 400 to each other. Next, the distance from the top of the first polishing pad 300 to the bottom of the second polishing pad 400 using the sensor 500, that is, the thickness of the first polishing pad 300 and the second polishing pad 400. Measure the total thickness.

In this case, the total thickness may be measured as H11, H22, and H33 by the first sensor 510, the second sensor 520, and the third sensor 530, respectively. Since H11, H22, and H33 differ in the amount of wear of each portion of the polishing pad, an error may occur, so that the average value of H11, H22, and H33 can be determined as the total thickness after wear.

Next, the difference between the reference total thickness and the total thickness after the wear is calculated. The calculated result is the total amount of wear of the first polishing pad 300 and the second polishing pad 400. The total amount of abrasion obtained in this manner may be regarded as the amount of abrasion to be compared with a set value when the replacement of the first polishing pad 300 or the second polishing pad 400 is determined.

According to the amount of wear of the first polishing pad 300 and the second polishing pad 400, it is possible to determine whether to adjust the operation time of the first polishing pad 300 and the second polishing pad 400 or to replace them. This will be described below with reference to FIG. 6.

5 is a flowchart illustrating a method of operating a wafer 10 polishing apparatus according to an embodiment. The method of operating the polishing apparatus of the wafer 10 may include a strain measuring step S110, a strain calculating step S120, a comparison step S130, and a dressing step S140.

In the deformation amount measuring step S110, the deformation amount of the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 may be measured through the plurality of sensors 500 provided in the upper surface plate 100. The deformation measuring method has already been described above.

In the deformation calculation step S120, the deformation amount of the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 may be digitized. In this case, the numerical operation may be performed by the calculator 800 electrically connected to the plurality of sensors 500.

As described above, the quantified deformation amount may set, for example, the maximum value among the deformation amounts measured from the plurality of sensors 500 as the reference deformation amount. In addition, the reference deformation amount may be used as the deformation amount to be compared with the set value when determining whether the dressing.

In the comparison step S130, the numerical value of the deformation amount may be compared with a preset set value. In this case, as described above, the maximum value and the set value of the plurality of numerical values of the deformation amount may be compared with each other.

At this time, the set value may vary depending on the production conditions of the wafer 10, the size, shape, etc. of the wafer 10, for example, may be set in the range of 1.5μm to 10μm, more preferably from 3μm to It can be set in the 5μm range.

When the numerical value of the deformation amount is less than or equal to the set value, the deformation amount may be returned to the step S110. When the numerical value of the deformation exceeds the set value, the dressing step S140 may be performed.

In addition, in the comparison step (S130), when the numerical value of the deformation exceeds the set value, it is possible to send a warning sound or warning message. This is to send a warning sound or a warning message to allow the worker to proceed with the dressing step (S140) without placing it.

In other words, if you miss the time to proceed to the dressing step (S140) and continue the polishing process, serious damage may occur to the wafer 10 to be polished, so that the worker to proceed to the dressing step (S140) without missing a time For sake.

In this case, the warning sound or warning message may be issued by the controller 900 that controls the overall polishing process of the wafer 10, and the warning message may be sent from the controller 900 by voice, text, or other various methods.

In the dressing step S140, the bottom surface of the first polishing pad 300 and the top surface of the second polishing pad 400 may be dressed. As mentioned above, the dressing operation can be carried out using, for example, a plate to which diamond is attached.

In the dressing step (S140), to remove foreign matter adhered to the polishing pad, to soften the hardened portion of the polishing pad, in the case of the polishing pad formed of a non-woven fabric, such as to raise the lint of the polishing pad lying in one direction Can be.

After dressing to repair the damage of the polishing pad, the polishing process can be performed again to prevent or significantly reduce the damage of the wafer 10 due to the damage of the polishing pad. As mentioned above, the dressing operation can be carried out in such a manner as to rub the deformed portion of the polishing pad using, for example, a diamond-attached plate.

6 is a flowchart illustrating a method of operating a wafer 10 polishing apparatus according to another embodiment. 7 is a graph showing a relationship between the wear amount of the first polishing pad 300 and the second polishing pad 400 and their operating time according to an embodiment.

The method of operating the polishing apparatus of the wafer 10 may include a wear amount measuring step S210, a determining step S220, a pad operating time adjusting step S230, and a pad replacing step S240.

In the wear amount measurement step (S210), the amount of wear on the bottom surface of the first polishing pad 300 and the top surface of the second polishing pad 400 may be measured through the plurality of sensors 500 provided in the upper surface plate 100. The method for measuring the amount of wear has already been described above.

That is, the wear amount is a thickness in a state where the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 are not worn and a thickness in a worn state after the polishing process of the wafer 10 is performed. It can be measured by comparing with each other.

In this case, the amount of wear on the lower surface of the first polishing pad 300 and the upper surface of the second polishing pad 400 may be digitized by the calculator 800 electrically connected to the plurality of sensors 500. The amount of wear measured and quantified is the total amount of wear that is added to the amount of wear on the bottom surface of the first polishing pad 300 and the top surface of the second polishing pad 400.

In the determination step (S220), it may be determined whether the measured amount of wear exceeds a predetermined set value. In this case, the set value may vary depending on the shape, performance, etc. of the polishing apparatus of the wafer 10, for example, a sum of the thicknesses of the first polishing pad 300 and the second polishing pad 400 that are not worn. It can be set to 10% to 20% of, more preferably 15%.

Depending on whether or not the amount of wear in the determination step (S220) exceeds the set value, the pad operation time adjustment step (S230) or the pad replacement step (S240) may proceed.

When the measured wear amount is less than or equal to the set value, a pad operating time adjusting step S230 may be performed. In the pad operating time adjusting step S230, the first polishing pad 300 and The operating time of the second polishing pad 400 may be adjusted.

Table 1 below shows the wear amount of the polishing pad and the operating time of the polishing pad according to one embodiment. 7 is a graph showing Table 1 below.

In this case, the amount of wear, the first polishing pad 300 and the second polishing pad 400 to the value of the sum of the thickness of the first polishing pad 300 and the second polishing pad 400 is not worn, It is expressed as the ratio of the sum of the thicknesses of. The operating time is also expressed as a percentage of increased time for when the wear amount is 0% to 8%.

Table 1

Wear amount (%)	Operating time (%)
0 to 8	No increase
Over 8 ~ 10	5
Over 10 ~ 12	10
Over 12 ~ 15	15

In Figure 7, T represents the operating time when the wear amount is 0% to 8%, T1 is the time when the operating time is increased by 5% in T time, T2 is the time increased by 10% in T time, T3 is 15% increase in time, respectively.

Therefore, it can be seen that the pad operating time of the embodiment generally increases with the amount of wear. On the other hand, in the embodiment, the set value is, for example, 15%. That is, when the amount of wear exceeds 15%, the pad replacement step (S240) may proceed.

On the other hand, in the pad operation time adjustment step (S230), the control unit 900 for controlling the polishing process of the wafer 10 can adjust the pad operation time. The controller 900 may control the entire process including operation or shutdown of the wafer 10 polishing apparatus.

In the pad replacement step S240, the first polishing pad 300 or the second polishing pad 400 may be replaced. If the measured wear amount exceeds the set value, the pad replacement step S240 may be performed.

When the wear amount exceeds the set value, the first polishing pad 300 or the second polishing pad 400 may be considered to have reached the end of its life as a polishing pad, and thus the polishing pads are replaced. In this case, both the first polishing pad 300 and the second polishing pad 400 may be replaced, or if necessary, any one of the first polishing pad 300 and the second polishing pad 400 may be replaced.

In an embodiment, the sensor 500 may accurately measure the amount of deformation or wear of the polishing pad of the polishing apparatus of the wafer 10.

Therefore, the wafer 10 polishing apparatus and its operation method of the embodiment can prevent or significantly reduce the damage of the wafer 10 in the wafer 10 polishing process, and have an effect of shortening the working time.

As described above in connection with the embodiment, only a few are described, but other forms of implementation are possible. The technical contents of the above-described embodiments may be combined in various forms as long as they are not incompatible with each other, and thus may be implemented in a new embodiment.

In an embodiment, the sensor can accurately measure the amount of deformation or wear of the polishing pad of the wafer polishing apparatus. Therefore, there is industrial applicability.

Claims

Donut-shaped top plate;

A lower plate formed in a donut shape and disposed below the upper plate;

A first polishing pad attached to a lower surface of the upper surface plate and polishing one surface of the wafer;

A second polishing pad attached to an upper surface of the lower plate and polishing the other surface of the wafer; And

A sensor arranged in a plurality in the radial direction of the upper plate, the sensor for measuring the amount of deformation or wear of the lower surface of the first polishing pad and the upper surface of the second polishing pad

Wafer polishing apparatus comprising a.
The method of claim 1,

Between the first polishing pad and the second polishing pad,

And a driving unit for rotating and revolving the wafer.
The method of claim 2,

The driving unit,

driving axle;

A tooth gear is formed on an outer circumferential surface, the sun gear coupled to the drive shaft to rotate about the drive shaft in accordance with the rotation of the drive shaft;

A ring gear disposed around the drive shaft, spaced apart from the sun gear in a radial direction, and having a tooth formed on an inner circumferential surface thereof; And

A tooth is formed on an outer circumferential surface, and meshes with the sun gear and the ring gear, and a carrier on which the wafer is mounted.

Wafer polishing apparatus comprising a.
The method of claim 3,

And the carrier rotates about the drive shaft and rotates simultaneously as the drive shaft rotates.
The method of claim 3,

The sensor,

Wafer polishing apparatus, characterized in that for measuring the distance to the carrier to measure the deformation amount of the first polishing pad and the second polishing pad.
The method of claim 1,

The sensor,

Wafer polishing apparatus, characterized in that for measuring the amount of wear of the first polishing pad and the second polishing pad by measuring the distance between the top plate and the bottom plate.
The method of claim 1,

Wafer polishing apparatus, characterized in that the sensor is an eddy current sensor.
The method of claim 1,

And a measuring unit provided at the upper surface plate and measuring a thickness of the wafer.
The method of claim 1,

And an operation unit electrically connected to the sensor and configured to quantify the amount of deformation or wear of the first polishing pad and the second polishing pad.
The method of claim 1,

And a control unit electrically connected to the operation unit and controlling a polishing process of the wafer.
Measuring a deformation amount of the lower surface of the first polishing pad and the upper surface of the second polishing pad through a plurality of sensors provided in the upper surface plate;

A deformation amount calculating step of quantifying a deformation amount of the lower surface of the first polishing pad and the upper surface of the second polishing pad in a calculation unit electrically connected to the plurality of sensors;

A comparison step of comparing the numerical value of the deformation amount with a preset set value; And

Dressing step of dressing the lower surface of the first polishing pad and the upper surface of the second polishing pad when the quantified deformation amount exceeds the set value.

Wafer polishing apparatus operating method comprising a.
The method of claim 11,

In the comparison step,

And a maximum value and a set value of the plurality of numerical values of the deformation amount are compared with each other.
The method of claim 11,

In the comparison step,

And a warning sound or a warning message is sent by the controller for controlling the polishing process of the wafer when the quantified deformation amount exceeds the set value.
The method of claim 11,

Wafer polishing apparatus operating method characterized in that the set value is 1.5μm to 10μm.
The method of claim 14,

The set value is a wafer polishing apparatus operating method, characterized in that 3μm to 5μm.
Measuring the amount of wear on the lower surface of the first polishing pad and the upper surface of the second polishing pad through a plurality of sensors provided on the upper surface plate;

A determination step of determining whether the measured amount of wear exceeds a predetermined set value;

A pad operating time adjusting step of adjusting an operating time of the first polishing pad and the second polishing pad according to the measured wear amount when the measured wear amount is less than the set value; And

A pad replacement step of replacing the first polishing pad or the second polishing pad when the measured amount of wear exceeds the set value

Wafer polishing apparatus operating method comprising a.
The method of claim 16,

The wear amount is measured by comparing the thickness of the lower surface of the first polishing pad and the upper surface of the second polishing pad with no wear and a thickness of the wear state after the polishing process of the wafer is compared with each other. How the device works.
The method of claim 16,

And an amount of wear on the lower surface of the first polishing pad and the upper surface of the second polishing pad in the calculation unit electrically connected to the plurality of sensors.
The method of claim 16,

In the pad operation time adjustment step,

Wafer polishing apparatus operating method characterized in that for controlling the pad operation time in the control unit for controlling the polishing process of the wafer.
The method of claim 16,

The set value is a method of operating a wafer polishing apparatus, characterized in that 10% to 20% of the sum of the thickness of the first polishing pad and the second polishing pad is not worn.