JP2013045819A - Quantitative measuring method of polishing pressure distribution of chemical mechanical polishing using atomic force microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for obtaining a polishing pressure distribution from a two-dimensional distribution of a surface potential measured by an EFM.SOLUTION: The method of the invention is a method for obtaining a polishing pressure distribution of chemical mechanical polishing. The method includes processes of obtaining a surface potential image by measuring a surface potential of an object to be polished which is polished by a polishing apparatus with an electric force microscope, and transforming the surface potential to a polishing pressure on the basis of data which shows a relationship between a surface potential and a polishing pressure.

Description

  The present invention relates to a polishing characteristic and a surface state evaluation technique in substrate processing of a semiconductor wafer or the like using chemical mechanical polishing.

  In recent years, semiconductor devices have become ultrafine and highly integrated, and along with this, surface planarization technology has become an important and essential process. This surface planarization technology not only manufactures semiconductor substrates such as Si, SiC, GaAs, and GaN, which are the starting point of the manufacturing process, but also the subsequent element isolation regions, gate electrodes, wiring / contact electrodes, and multilayer wiring insulation. It is also widely applied in wafer processes such as layers.

  With the miniaturization and high integration of devices, the flatness requirement for surface planarization technology has become strict, and all stages such as wafer level global planarization, in-chip planarization, device level planarization, etc. Therefore, the flatness of the nm level is required. For example, in a damascene structure using copper wiring, the amount of overpolishing of the copper wiring part such as dishing and erosion is required to be 5 nm or less.

  Furthermore, with the miniaturization of elements, requirements for the size and density of defects generated in the process are becoming stricter. As the minimum dimension of the element approaches 10 nm, the allowable defect size is reduced to a few nm level.

  In response to such demands, surface planarization technology uses finer polishing particles, adoption of composite structure abrasive particles, reduction of polishing pressure, control of slurry flow, improvement of polishing pad material, pad being polished Many improvements have been made, such as temperature control and the development of additives in the slurry.

  However, defects that are difficult to detect with these defect inspection techniques and evaluation techniques, or uneven local physical properties of the surface that cause defects, have recently become a problem. One example is the surface potential distribution. As a technique for measuring the surface potential distribution, there is a commercially available device, ChemceptriQ, manufactured by Qcept. This apparatus is an apparatus for measuring the surface potential distribution at the wafer level by applying the Kelvin probe technology. Using this apparatus, it has been found that there is a correlation between the region where the potential on the wafer surface changes greatly and the distribution of defects due to particle adhesion.

  Such a local potential change may be caused by a substantial defect such as contamination, but in many cases, a local charge due to a process such as a plasma treatment or a high resistance pure water cleaning treatment is caused. This is due to non-uniformity. Such local potential changes are difficult to detect with conventional evaluation techniques. Also, this ChemetriQ is a macroscopic evaluation technique at the wafer level, and cannot be used for evaluating a minute area at a patterned level.

  As an apparatus that can measure the potential distribution in this minute region, there is a Kelvin Force Microscopy (KFM) that applies the function of AFM. There is also a measuring device called an electric force microscope (EFM) using a technique close to this KFM. These microscopes detect the force that the surface potential distribution acts on the probe by scanning the surface of the sample in a non-contact manner with the probe.

FIG. 1A is a schematic diagram for explaining the principle of KFM. When a bias voltage (AC voltage V _{AC of} frequency ω + offset voltage V _OFF ) is applied between the cantilever 2 and the sample 1, the cantilever 2 vibrates due to electrostatic force acting between the cantilever 2 and the sample 1. The cantilever 2 is irradiated with light from the laser 7, and the reflected light is received by the photodetector 8. A displacement signal of the probe 3 obtained by the photodetector 8 is input to the lock-in amplifier 10, and at the same time, a bias voltage (V _AC + V _OFF ) is input to the lock-in amplifier 10. The lock-in amplifier 10 takes out the amplitude A _{ω of the} probe 3 that is substantially proportional to the electrostatic force F _C acting between the sample 1 and the probe 3.

The amplitude A _ω is a vibration component of the frequency ω and is expressed by the following equation.
_{A ω = (∂C / ∂Z)} (V S + V OFF) V AC (1)
Here, C represents the capacitance between the probe 3 at the tip of the cantilever 2 and the sample 1, Z represents the distance between the probe 3 and the sample 1, and V _S represents the surface potential of the sample 1. ing.

The amplitude A _ω is sent to the feedback controller 11 where the offset voltage V _OFF is feedback controlled so that A _ω becomes 0, that is, V _S + V _OFF = 0. Therefore, the surface potential V _S of the sample 1 is obtained as −V _OFF .

FIG. 1B is a schematic diagram for explaining the principle of EFM. Although the basic principle is the same as that of KFM, feedback control of the offset voltage V2 is not performed in EFM. The lock-in amplifier 10 detects the amplitude Aω of the probe 3 that is substantially proportional to the electrostatic force F _C acting between the sample 1 and the probe 3. This amplitude Aω is a vibration component of the frequency ω and is expressed by the following equation.
A _ω = (∂C / ∂Z) (V _S + V ₂ ) V _AC (2)

  The lock-in amplifier 10 further detects the vibration components Aωsinφ and Aωcosφ and outputs them. Here, φ represents the phase of the probe vibration and is determined from the electrical characteristics of the sample 1 and the mechanical characteristics of the cantilever 2. The vibration component Aωcosφ substantially corresponds to the surface potential of the sample 1. Therefore, the vibration component Aωcosφ is obtained as the surface potential of the sample 1.

  The difference between KFM and EFM is that KFM detects a bulk physical property such as a work function of a sample, whereas EFM detects a surface charge distributed on the extreme surface. Furthermore, KFM is capable of quantitative measurement because it uses the offset voltage fed back to the sample as a measurement value, but EFM cannot perform quantitative measurement.

  On the other hand, since KFM measures the offset voltage fed back to the sample as the surface potential, it is effective for measuring the surface potential of conductive materials and semiconductor materials. However, the quantitative properties of insulating materials are lost. End up. This is because the actual surface potential of the insulating material is different from the offset voltage in KFM. That is, the offset voltage is a voltage applied to the substrate that is the base of the insulating film, and does not correspond to the surface potential of the insulating film.

  Further, in an actual semiconductor device, for example, a wiring structure is formed on a semiconductor substrate. When KFM measurement is performed in such a state, the potential drop due to the resistance component of the semiconductor substrate affects the bias voltage applied at the time of KFM measurement, so that the feedback offset voltage does not reflect the actual surface potential of the wiring. There are drawbacks.

  On the other hand, the EFM measurement does not employ the feedback voltage to the sample as the surface potential, but measures the surface potential as it is for both the conductive material and the insulating material. However, since EFM does not measure the actual voltage value of the feedback voltage, a problem remains from the viewpoint of quantitative measurement. As described above, EFM measurement is an effective technique for evaluating the surface potential, but it has not been often used sufficiently from the viewpoint of quantitative measurement. Therefore, compared with KFM, EFM has hardly been applied to actual semiconductor device structures.

  In CMP (Chemical Mechanical Polishing), the polishing pressure applied to the wafer is a very important process parameter. First, the polishing pressure greatly affects the polishing rate. The polishing pressure distribution macroscopically affects the flatness within the wafer surface, and microscopically affects the pattern dependence of flatness such as dishing and erosion. Therefore, it is necessary to accurately grasp the polishing pressure and its uniformity in the CMP processing of fine elements that require high flatness.

  Conventionally, as a method for directly measuring the polishing pressure of CMP, a method using pressure sensitive paper or the like, a method using a pressure sensor, or the like is used. However, these conventional methods are macroscopic measurement methods on the wafer surface, and the microscopic pressure distribution in the pattern structure cannot be measured.

JP 2010-74119 A JP 2008-89444 A

  The present inventor has made many EFM and KFM evaluations in order to apply the AFM technique to the evaluation of the surface of a semiconductor device, particularly a planarization polishing process. Found that you can get.

  The semiconductor element is composed of a semiconductor material, a conductive material constituting the wiring, an insulating material for maintaining the insulation of the wiring, and the like. Therefore, the object of the planarization polishing process is a semiconductor wafer in which materials having these different characteristics are mixed, and the object whose surface characteristics are evaluated is the surface where the semiconductor material, the conductive material, the insulating material, and the like are simultaneously exposed.

  For this reason, EFM, which can evaluate all materials including insulating materials, is more suitable as a method for evaluating the surface potential in the manufacturing process of semiconductor elements than KFM which is effective for semiconductor materials and conductive materials. I understand that

  The present inventor has discovered a phenomenon in which a mechanical pressure necessary for polishing changes a surface potential of a substrate to be polished or a surface potential is generated in a surface polishing / flat process. By utilizing the relationship between the polishing pressure and the surface potential, the polishing pressure can be estimated from the surface potential. Furthermore, it was found that the non-uniformity of the polishing pressure can be evaluated by obtaining a two-dimensional surface potential distribution.

  Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and provides a method for obtaining the polishing pressure distribution from the two-dimensional distribution of the surface potential measured by the EFM. It is for the purpose.

  In order to achieve the above-described object, one embodiment of the present invention is a method for obtaining a polishing pressure distribution of chemical mechanical polishing, in which a surface potential of an object polished by a polishing apparatus is measured by an electric force microscope. Then, a surface potential image is obtained, and the surface potential is converted into a polishing pressure based on data indicating a relationship between the surface potential and the polishing pressure.

  In a preferred aspect of the present invention, the data indicating the relationship between the surface potential and the polishing pressure is obtained by using the probe of the electric force microscope in contact with the object to be polished at a predetermined pressure. It is obtained by scanning a surface and measuring the surface potential of the scanned object to be polished.

  In a preferred aspect of the present invention, the data indicating a relationship between the surface potential and the polishing pressure is obtained by using the probe with the electric force microscope in contact with the object to be polished with a first pressure. The surface of the object to be polished scanned at the first pressure is measured, and the probe is brought into contact with the object to be polished at the second pressure with the probe. It is obtained by scanning the surface of a polished object and measuring the surface potential of the polished object scanned at the second pressure.

  According to the present invention, by measuring the surface potential of an object to be polished after the polishing process, it is possible to quantitatively grasp how much pressure the surface of the object to be polished is actually polished. Furthermore, the polishing pressure distribution during polishing of the workpiece can be quantitatively and accurately grasped from the two-dimensional distribution data of the surface potential. Furthermore, in an actual pattern element in which different materials coexist, the polishing pressure applied to each material and its pattern dependence can be quantitatively understood. By feeding back the surface potential measurement results by these EFMs to CMP conditions, not only the optimization of processes related to CMP equipment, such as optimization of abrasive particles, polishing pads, slurry chemicals, optimization of polishing pressure control method, etc. The material of the object to be polished can also be optimized.

FIG. 1A is a diagram for explaining the operating principle when measuring the surface potential of a Kelvin force microscope (KFM), and FIG. 1B is for explaining the operating principle when measuring the surface potential of an electric force microscope (EFM). FIG. FIG. 2A is a diagram showing a surface potential image of the SiOC film after contact scanning the central region (20 × 20 μm) with a probe, and FIG. 2B is the SiOC film shown in FIG. It is a figure which shows the cross-sectional profile of surface potential. 2 is a surface potential image of a Si surface whose surface is flattened at the atomic level by CMP. It is a figure which shows the surface potential image of the Ru metal film after carrying out contact scanning of the area | region (20 * 20 micrometer) of the center part with a probe. It is a graph which shows the quantitative relationship between the mechanical polishing pressure of Ru film | membrane, and surface potential. 6A is a diagram showing a surface potential image of the Ru film having a scratch, and FIG. 6B is a diagram showing a cross-sectional profile of the surface potential of the Ru film shown in FIG. 6A. It is a perspective view which shows a grinding | polishing apparatus.

Hereinafter, embodiments of the present invention will be described.
The inventor observed the surface state after CMP polishing in the process of EFM evaluation, and found the fact that nonuniform polishing pressure and mechanical stimulation by polishing change the surface potential of the material to be polished. In all metal materials, insulating film materials, and semiconductor materials, the surface potential was changed by mechanical stimulation. The generation of a potential due to mechanical deformation is a well-known fact as a piezo effect in ferroelectric materials such as lead zirconate titanate (PZT). However, in low dielectric constant insulating materials (for example, low-k materials), metal wiring materials, and barrier metal materials used in wiring structures, the fact that the surface potential changes due to mechanical stimulation such as the piezo effect is Not reported. Furthermore, a change in resistance such as a change in piezoresistance is also known in a semiconductor material such as Si, but no change in surface potential due to mechanical deformation is known.

  2A shows an EFM surface potential image (40 × 40 μm) of the SiOC film which is a low dielectric constant insulating film, and FIG. 2B shows a cross-sectional profile of the surface potential of the SiOC film. A central region (20 × 20 μm) surrounded by a dotted line is a region scanned by bringing the probe into contact with the SiOC film before the EFM measurement. The purpose of scanning with the probe in contact with the SiOC film is to apply mechanical pressure to the SiOC film in order to realize a state of mechanical polishing in which polishing particles are pressed against the material to be polished in actual CMP. It is to determine the relationship between the resulting surface potential and pressure. At the time of contact scanning with the probe, no bias voltage is applied to the probe and the SiOC film, and they are in the same potential state. From FIG. 2A and FIG. 2B, it can be clearly seen that the surface potential changes to the negative side in the region subjected to the mechanical stimulation by the probe contact.

  The probe used was a Si probe coated with an Rh film having conductivity suitable for EFM measurement, and the spring constant of the cantilever was 1.6 N / m. The force for pressing the SiOC film during probe scanning was 153 nN, which was a very small force. Therefore, there was no fact that the SiOC film was scraped by scanning the probe, and no change in the surface shape was found from the AFM shape measurement after scanning.

  On the other hand, as shown in FIGS. 2 (a) and 2 (b), the surface potential is found to decrease by 100 mV in the region where the probe is in contact. Such a potential change due to mechanical stimulation can occur in a material such as PZT which is a ferroelectric material, and such a phenomenon is known as a piezo effect. However, it is not known that a potential change due to mechanical stimulation occurs in a low dielectric constant SiOC film. From this result, it can be easily imagined that the surface potential of the object to be polished may change in the surface polishing process such as CMP.

  Further, the present inventor has confirmed that a surface potential change due to mechanical stimulation also occurs in a semiconductor material such as Si. FIG. 3 is a diagram showing a surface potential image of a recycled Si wafer whose surface is polished by CMP. A recycled wafer is a wafer that is reused repeatedly by polishing its surface from the viewpoint of saving resources. As shown in FIG. 3, a pattern of surface potential that is considered to be a polishing trace clearly appears. Although the contrast difference between light and dark in the surface potential image is as small as 4 mV, it can be sufficiently distinguished. The wafer surface was flattened so that no irregularities could be detected. Therefore, it can be considered that the pattern of the surface potential image exhibits polishing non-uniformity. Thus, it can be seen that non-uniformity of polishing can be detected by observing the surface to be polished through the surface potential.

  FIG. 4 shows a surface potential image including a contact scan region by a probe for the Ru barrier film which is a metal film. A central region (20 × 20 μm) surrounded by a dotted line is a region scanned by bringing the probe into contact with the Ru film before the EFM measurement. Similar to the insulating film material and the semiconductor material, it can be seen that the surface potential of the metal film is changed by contact scanning with the probe. In this case, unlike the SiOC film, the potential of the region in contact with the probe is increased. It is not yet known why the potential of such a probe contact region (that is, the polishing region) changes to the negative side in the insulating film and to the positive side in the metal film. Also in the case of Ru, the surface shape image data showed no irregularities on the surface.

  Although the cause of the change in surface potential due to mechanical stimulation is not well understood, the present inventor believes that the atomic arrangement on the surface is disturbed by mechanical stimulation and the electronic state of the atom changes. Furthermore, the present inventor has also found that the surface potential due to mechanical stimulation is correlated with the pressure that gives mechanical stimulation.

  The relationship between the surface potential and the pressure can be obtained as follows. The surface of the object to be polished is scanned by contacting an EFM (Electron Force Microscope) probe at a predetermined pressure, and after scanning, the surface potential is measured by EFM, and in a region including two of a scan region and a non-scan region. Surface potential data is acquired, the probe is brought into contact with the surface of the object to be polished at different pressures and scanned, and the surface potential after scanning at different pressures is measured by EFM. In this way, the relationship between the probe pressure and the surface potential of the object to be polished is obtained.

  The measurement of the surface potential by EFM is performed in a state where the probe is not in contact with the object to be polished. The pressure of the probe against the object to be polished can be obtained from mechanical conditions such as the tip area of the probe, the spring constant of the cantilever, and the amount of displacement. The probe pressure can be varied by using cantilevers with different spring constants.

  The probe pressure at the time of contact scanning represents a microscopic polishing pressure applied from the abrasive particles to the object to be polished during actual polishing. In wafer polishing (CMP), abrasive particles having an average particle size of usually 100 nm to several hundreds of nm are usually used. The polishing pressure is calculated using the contact area of the abrasive particles with the wafer surface. It should be noted that a predetermined conversion is required to obtain the actual macroscopic polishing pressure applied to the entire wafer surface. The relationship between the probe pressure and the surface potential obtained as described above corresponds to the relationship between the polishing pressure and the surface potential. Since the relationship between the pressure and the surface potential varies depending on the type of material, it is preferable to acquire data indicating the relationship between the pressure and the surface potential for each material.

  FIG. 5 shows data showing the relationship between the probe pressure (ie, mechanical polishing pressure) and the surface potential in the Ru film. The graph shown in FIG. 5 is obtained from the surface potentials at three different pressures (0, first pressure P1, and second pressure P2). The surface potential at zero pressure is obtained by measuring the surface potential before applying the polishing pressure to the object to be polished (that is, before polishing the object to be polished).

  By using data indicating a quantitative relationship between the polishing pressure and the surface potential as shown in FIG. 5, the surface potential can be converted into the polishing pressure. The relationship between pressure and surface potential depends on the type of material being polished. Therefore, when polishing elements made of different materials, such data is acquired in advance for each material. Then, by acquiring the surface potential image before and after polishing, it is possible to quantitatively estimate the polishing pressure applied to the element.

  Further, based on the quantitative relationship between the polishing pressure and the surface potential, a surface pressure image (that is, a two-dimensional surface potential distribution) as shown in FIG. 3 is used to obtain a polishing pressure image (that is, a two-dimensional polishing pressure distribution). It is also possible to convert to

  Scratches are a frequently observed defect in CMP processes. FIG. 6A shows the potential image of the Ru film obtained after linearly moving the probe in the vertical direction to simulate this scratch defect, and FIG. 6B shows the cross-sectional profile of the surface potential. ing. Also in this case, a cantilever probe having a spring constant of 1.6 N / m was pressed against the Ru film with a minute force of 153 nN. From FIG. 6A and FIG. 6B, it can be seen that the trace of the probe is in the form of a vertical line.

  Thus, it can be seen that a scratch that does not actually affect the surface irregularities and does not become defective can be detected as a change in potential in the surface potential image. By observing the EFM surface potential in detail, although it does not actually become defective, it is possible to detect the cause of the failure that is a precursor. Therefore, it is possible to prevent defects from occurring and contribute to high process reliability.

  From these results, it was found that the distribution of the polishing pressure can be detected as an EFM surface potential image by using EFM. That is, the polishing pressure actually applied to the object to be polished can be quantitatively determined from the surface potential image. Furthermore, the distribution of the polishing pressure on the surface to be polished can also be acquired.

  Further, in a pattern element composed of various different materials, it is possible to estimate a pressure actually applied to each material and a change in polishing pressure caused by the pattern. This can be particularly useful for the study of generation mechanisms such as erosion and dishing. Also, no irregularities are detected in the surface shape, and it is not actually defective, but when a linear pattern is visible in the surface potential image, it becomes apparent as a scratch when the polishing pressure is increased. Predict that there is a possibility. By feeding back such a surface potential image to the polishing process, generation of defects can be prevented in advance.

  The quantitative measurement method of the polishing pressure described above can be performed using an existing electric force microscope (EFM) shown in FIG. Further, this method can be applied to polishing evaluation of a semiconductor wafer polished by the polishing apparatus 20 shown in FIG. The polishing apparatus 20 is a CMP apparatus that can perform chemical mechanical polishing. Hereinafter, the polishing apparatus 20 will be described with reference to FIG.

  The polishing apparatus 20 includes a polishing table 22, a top ring head 26 connected to the upper end of the support shaft 24, a top ring shaft 28 attached to the free end of the top ring head 26, and a lower end of the top ring shaft 28. And a connected top ring 30. The top ring shaft 28 is rotationally driven by a top ring rotation motor (not shown).

  The polishing table 22 is connected to a motor (not shown) arranged below the table shaft 22a, and is rotatable around the table shaft 22a. A polishing pad 32 is affixed to the upper surface of the polishing table 22, and the upper surface (polishing surface) 32a of the polishing pad 32 constitutes a polishing surface for polishing a semiconductor wafer. The semiconductor wafer is held on the lower surface of the top ring 30 by vacuum suction.

  The top ring 30 rotates around the top ring shaft 28 by the rotation of the top ring shaft 28. Further, the top ring shaft 28 moves up and down with respect to the top ring head 26 by a vertical movement mechanism 34, and the top ring 30 moves up and down with respect to the top ring head 26 by the vertical movement of the top ring shaft 28. It comes to move. The top ring head 26 is configured to be pivotable about the support shaft 24.

  The polishing of the semiconductor wafer is performed as follows. The top ring 30 holding the semiconductor wafer on the lower surface is moved above the polishing table 22 from the receiving position of the semiconductor wafer by turning the top ring head 26. The top ring 30 and the polishing table 22 are rotated, and a polishing liquid (slurry) is supplied to the upper surface 32 a of the polishing pad 32 from a polishing liquid supply nozzle (not shown) provided above the polishing table 22. Then, the top ring 30 is lowered by the vertical movement mechanism 34 to press the semiconductor wafer against the upper surface (polishing surface) 32 a of the polishing pad 32. In this manner, the surface of the semiconductor wafer is polished by bringing the semiconductor wafer into sliding contact with the polishing surface 32 a of the polishing pad 32.

  Reference numeral 40 denotes a dressing unit for dressing the polishing surface 32 a of the polishing pad 32 of the polishing table 22. The dressing unit 40 includes a dresser 50 slidably contacted with the polishing surface 32a, a dresser shaft 51 to which the dresser 50 is connected, an air cylinder 53 provided at the upper end of the dresser shaft 51, and the dresser shaft 51. And an oscillating arm 55 that is supported by the arm. The lower part of the dresser 50 is constituted by a dressing member 50a, and diamond abrasive grains adhere to the lower surface of the dressing member 50a. The air cylinder 53 is disposed on a support base 57 supported by the support posts 56, and these support posts 56 are fixed to the swing arm 55.

  The swing arm 55 is driven by a motor (not shown) so as to turn around a support shaft 58. The dresser shaft 51 is rotated by driving a motor (not shown), and the dresser 50 is rotated around the dresser shaft 51 by the rotation of the dresser shaft 51. The air cylinder 53 lowers the dresser 50 via the dresser shaft 51 and presses the dresser 50 against the polishing surface 32a of the polishing pad 32 on the rotating polishing table 22 with a predetermined pressing force. The polishing pad 32 is scraped off by the lower surface (diamond abrasive grains) of the rotating dressing member 50a, whereby the polishing surface 32a is dressed. During dressing, pure water is supplied to the polishing surface 32a from a pure water supply nozzle (not shown).

  The semiconductor wafer polished by the polishing apparatus 20 is cleaned and dried by a cleaning machine and a dryer (not shown). Then, the semiconductor wafer is transferred to a known electric force microscope (EFM) shown in FIG. 1B, where a surface potential image of the semiconductor wafer is acquired as described above. The surface potential appearing in the surface potential image is converted into the polishing pressure, whereby the polishing pressure distribution on the surface to be polished is obtained. If the polishing pressure is not uniform, the result is fed back to the polishing apparatus 20, and the polishing pressure of the top ring 30 is adjusted based on the obtained polishing pressure distribution, and the flow rate and flow of the slurry are adjusted. be able to.

  The embodiment described above is described for the purpose of enabling the person having ordinary knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiment can be naturally made by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Accordingly, the present invention is not limited to the described embodiments, but is to be construed in the widest scope according to the technical idea defined by the claims.

DESCRIPTION OF SYMBOLS 1 Sample 2 Cantilever 3 Probe 7 Laser 8 Photo detector 10 Lock-in amplifier 11 Feedback controller 20 Polishing device 22 Polishing table 24 Spindle 26 Top ring head 28 Top ring shaft 30 Top ring 32 Polishing pad 34 Vertical movement mechanism 40 Dressing unit 50 Dresser 51 Dresser shaft 56 Post 57 Support base 58 Spindle

Claims (3)

A method for obtaining a polishing pressure distribution of chemical mechanical polishing,
A surface potential image is obtained by measuring the surface potential of an object polished by a polishing apparatus with an electric force microscope,
A method of converting the surface potential into a polishing pressure based on data indicating a relationship between the surface potential and the polishing pressure. The data showing the relationship between surface potential and polishing pressure is:
With the probe of the electric force microscope in contact with the object to be polished at a predetermined pressure, the surface of the object to be polished is scanned with the probe,
The method according to claim 1, wherein the method is obtained by measuring a surface potential of the scanned object to be polished. The data showing the relationship between surface potential and polishing pressure is:
With the probe of the electric force microscope in contact with the object to be polished at a first pressure, the surface of the object to be polished is scanned with the probe,
Measuring the surface potential of the object scanned at the first pressure;
With the probe in contact with the object to be polished at a second pressure, the probe scans the surface of the object to be polished,
The method according to claim 1, wherein the method is obtained by measuring a surface potential of the polishing object scanned with the second pressure.

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