Wafer polishing method and apparatus, data processing apparatus, program, and storage medium

Abstract

The invention relates to a wafer polishing method and apparatus, a data processing apparatus, a program, and a storage medium. The polishing method comprises the following steps: loading a wafer to be polished; reading in a first polishing formula, and carrying out primary polishing on the wafer according to the first polishing formula; wafer parameters of all the partitions of the wafer are detected, whether the wafer parameters of all the partitions of the wafer reach the standard or not is judged, if yes, the wafer is unloaded, if not, a second polishing formula is obtained through the dynamic adjustment model according to the wafer parameters, and secondary polishing is conducted on the partitions, not reaching the standard, of the wafer based on the second polishing formula. And then returning to detect the wafer parameters of the partitions of the wafer again until the wafer parameters of all the partitions of the wafer are judged to reach the standard, and unloading the polished wafer. According to the method, the reworking function of multi-zone automatic triggering and time-pressure automatic combined adjustment can be achieved in the wafer polishing process, repeated treatment on the whole wafer is avoided, and material consumption and cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical mechanical polishing of semiconductor wafers; more specifically, the present invention relates to a wafer polishing method and equipment, a data processing device, a program, and a storage medium. Background Art

[0002] Chemical Mechanical Polishing (CMP) is the preferred technology for flattening the surface of semiconductor wafers. In chemical mechanical polishing, for the manufacturing process of semiconductor devices, over-polishing may cause damage to material properties and affect device performance; if the polishing is insufficient, additional processing steps may be required, increasing costs.

[0003] In the process of applying the chemical mechanical polishing method, it is necessary to pre-set the endpoint stop parameters. When the polishing process of the wafer surface reaches the set endpoint stop parameters, the polishing of the wafer surface is stopped to obtain the processed wafer. The method of determining the polishing endpoint based on the endpoint stop parameters cannot accurately detect whether the surface morphology of the polished wafer meets the standard requirements, which will cause a large deviation between the wafer surface flatness and the actual flatness, and cannot be applied to wafers with multi-layer film structures. Summary of the invention

[0004] In view of this, the present invention provides a wafer polishing method and equipment, a data processing device, a program, and a storage medium, so as to solve or at least alleviate one or more of the above-mentioned problems and other problems existing in the prior art.

[0005] In order to achieve the above-mentioned object, a first aspect of the present invention provides a wafer chemical mechanical polishing method, wherein the polishing method comprises:

[0006] Step I: loading the wafer to be polished;

[0007] Step II: reading in a first polishing recipe, performing primary polishing on the wafer according to the first polishing recipe, and stopping the primary polishing by using an endpoint detection technology;

[0008] Step III: Detecting wafer parameters of all partitions of the wafer, and determining whether the wafer parameters of all partitions of the wafer meet the standards. If the wafer parameters of all partitions meet the standards, proceed to step V; if the wafer parameters of all or some of the partitions do not meet the standards, proceed to step IV.

[0009] Step IV: obtaining a second polishing recipe according to the wafer parameters of all the partitions by dynamically adjusting the model, performing secondary polishing on the partitions of the wafer that do not meet the standards based on the second polishing recipe, and returning to step III;

[0010] Step V: Unload the polished wafer and return to step I.

[0011] In the polishing method as described above, optionally, the parameters of the first polishing recipe and the second polishing recipe include polishing time, retaining ring pressure, and polishing pressure on each partition of the wafer.

[0012] In the polishing method as described above, optionally, the endpoint detection technology includes an eddy current endpoint detection method and / or an optical endpoint detection method and / or a motor torque endpoint detection method. The eddy current endpoint detection method uses the eddy current detection principle to measure the film thickness of the wafer, and the optical endpoint detection method uses the optical detection principle to measure the film thickness of the wafer.

[0013] In the polishing method as described above, optionally, the wafer parameters include the film thickness of the wafer.

[0014] In the polishing method as described above, optionally, the measurement principle of the film layer thickness of the partition of the wafer includes the eddy current detection principle and / or the optical detection principle.

[0015] In the polishing method as described above, optionally, the optical detection principle uses light of a certain wavelength to irradiate the wafer surface, and obtains the film thickness of the wafer by analyzing the reflected wavelength, wherein the lower limit of the goodness of fit is set to 0.98, and the goodness of fit is the degree of fit between the actually measured reflection wavelength curve and the wavelength curve calibrated by the machine, and if the goodness of fit is lower than the lower limit, re-measure or select a new measurement point.

[0016] In the polishing method as described above, optionally, at least one measurement point is set at each of the partitions of the wafer.

[0017] In the polishing method as described above, optionally, the dynamic adjustment model includes a calculation model for the polishing duration, and the calculation model for the polishing duration is:

[0018]

[0019] Wherein, T is the polishing time, PreZ[i]PointMax is the maximum value of the wafer parameter of the Z[i] partition, i=1,2,…,n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions of the wafer, and RR is the removal rate.

[0020] In the polishing method as described above, optionally, the dynamic adjustment model includes a calculation model of the polishing pressure of each partition of the wafer, and the calculation model of the polishing pressure is:

[0021]

[0022] Wherein, P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum wafer parameter value of the Z[i] partition, i=1,2,…,n, Target is the target wafer parameter value, n is the number of wafer partitions, 5≤n≤12, k is the empirical coefficient, and Thk_Offset_Spec is the standard control line.

[0023] In the polishing method as described above, optionally, the first polishing formula is a pre-set standard formula, and the second polishing formula is generated and adjusted in real time by the dynamic adjustment module according to the detection results of the wafer parameters.

[0024] In order to achieve the aforementioned object, a second aspect of the present invention provides a wafer polishing device, wherein the wafer polishing device is used to perform the polishing method described in any one of the first aspects, and the wafer polishing device comprises:

[0025] a polishing module, wherein the polishing module performs primary polishing on the wafer according to a first polishing recipe sent by the dynamic adjustment module or performs secondary polishing on the wafer according to a second polishing recipe, wherein the polishing module comprises a polishing disc, a polishing head, and a liquid supply device, wherein the polishing disc is covered with a polishing pad for polishing the wafer, the polishing head is loaded with the wafer, the wafer is pressed against the polishing pad on the polishing disc by the polishing disc, the liquid supply device sprays polishing liquid onto the surface of the polishing pad, and under the action of the polishing liquid, the relative movement of the polishing disc and the polishing pad causes the wafer to rub against the polishing pad so as to perform polishing;

[0026] An endpoint detection module, wherein the endpoint detection module detects wafer parameters of the wafer and stops polishing by using an endpoint detection technology, and the endpoint detection module sends the detection result of the wafer parameters to the dynamic adjustment module;

[0027] A dynamic adjustment module receives the detection result of the wafer parameter sent by the endpoint detection module, generates the second polishing recipe, and sends the first polishing recipe or the second polishing recipe to the polishing module. In order to achieve the aforementioned purpose, a third aspect of the present invention provides a data processing device, wherein the data processing device includes:

[0028] A memory, wherein the memory is used to store computer executable instructions or computer programs;

[0029] A processor, wherein the processor is used to implement the polishing method as described in any one of the first aspects above when executing the computer executable instructions or computer programs stored in the memory.

[0030] In order to achieve the aforementioned objectives, the fourth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions or a computer program, and when the computer-executable instructions or the computer program are executed by a processor, the polishing method as described in any one of the aforementioned first aspects is implemented.

[0031] In order to achieve the aforementioned objectives, the fifth aspect of the present invention provides a computer program, wherein the computer program includes computer executable instructions or a computer program, and when the computer executable instructions or the computer program are executed by a processor, the polishing method as described in any one of the aforementioned first aspects is implemented.

[0032] The present invention performs primary polishing on the wafer according to the first polishing formula, uses the endpoint detection technology to stop the polishing of the wafer, and performs secondary polishing by detecting the wafer parameters in different zones and dynamically updating the second polishing formula, thereby realizing the multi-zone automatic triggering rework function with automatic combined adjustment of time and pressure, improving the polishing efficiency, reducing the difficulty of rework, and improving product quality and production efficiency. The present invention can adjust the pressure in real time by zone during the wafer polishing process, has the function of automatic rework by zone, avoids repeated processing of the entire wafer, and reduces material consumption and cost.

[0033] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0035] Figure 1 A flow chart of an embodiment of a wafer polishing method according to the present invention is schematically shown;

[0036] Figure 2 is a schematic diagram of a polishing process of an embodiment of a wafer polishing method of the present invention;

[0037] Figure 3 A structural block diagram of an embodiment of a wafer polishing device according to the present invention is schematically shown;

[0038] Figure 4The structure block diagram of an embodiment of a data processing device according to the present invention is schematically shown.

[0039] Reference numerals :

[0040] 10 - the first film layer of the wafer; 20 - the second film layer of the wafer; 30 - the silicon substrate of the wafer. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in the field based on the embodiments in the embodiments of the present invention should fall within the scope of protection of the embodiments of the present invention.

[0042] It should be understood that, unless otherwise specified or logically contradictory, the various steps described in the method implementation of the present invention may be performed in different orders and / or in parallel. In addition, the method implementation may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0043] The term "including" and its variations used in this document are open inclusions, i.e., "including but not limited to". The term "based on" means "based at least in part on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments". In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Relevant definitions of other terms will be given in the following description.

[0044] In addition, in the present application document, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the order of the indicated technical features.

[0045] Figure 1 The flowchart of one embodiment of the wafer polishing method according to the present invention is schematically shown. As can be seen from the figure, the method may include steps I to V.

[0046] In step I, a wafer to be polished is loaded.

[0047] More specifically, in step I, the wafer to be polished needs to be loaded on the polishing head of the wafer polishing equipment for subsequent processing. For example, the wafer polishing equipment may include a polishing disc, a polishing head (or a carrier head), a liquid supply device, etc. The polishing disc may be covered with a polishing pad for polishing the wafer, and the wafer is loaded on the polishing head through a conductive rubber air film. The polishing head may press the wafer against the polishing pad on the polishing disc, and the liquid supply device may spray the polishing liquid onto the surface of the polishing pad. Under the chemical action of the polishing liquid, the relative movement of the polishing head and the polishing disc causes the wafer to rub against the polishing pad for polishing. After completing the loading of the wafer, proceed to step II.

[0048] In step II, the first polishing recipe is read in, primary polishing is performed on the wafer according to the first polishing recipe, and the primary polishing is stopped by endpoint detection technology (EPD).

[0049] As combined with step I, in an optional embodiment, chemical mechanical polishing technology is used to perform primary polishing on the wafer. Pressure is applied to the polishing head to make the wafer contact and rotate with the polishing pad. The polishing is stopped by endpoint detection technology to achieve preliminary flattening of the wafer surface.

[0050] In an optional embodiment, the parameters of the polishing recipe may include polishing time, holding ring pressure, and pressure on various partitions of the wafer.

[0051] The pressure applied to each partition of the wafer can be achieved through the conductive rubber air film of the polishing head. A conductive rubber air film can be provided on the wafer holding surface of the polishing head, and an annular partition air chamber can be provided in the conductive rubber air film. The pressure of each partition of the wafer can be adjusted by controlling the air volume in these annular partition air chambers. The wafer can be attached to the polishing head through the conductive rubber air film.

[0052] It can be understood that the polishing time refers to the time for the wafer to be polished, that is, the time from the start of polishing to the end of polishing. During the polishing process, too short a polishing time will result in insufficient polishing of the wafer, and too long a polishing time may cause the wafer to be over-polished, causing damage to the wafer surface. During the polishing process of the wafer, the wafer is fixed on the polishing head, and the retaining ring on the polishing head can ensure the stability of the position of the wafer during the polishing process. Correct and effective retaining ring pressure can ensure that the wafer surface is effectively polished. Too small a retaining ring pressure may cause the wafer to slide or shift during the polishing process, affecting the uniformity and accuracy of the polishing. Excessive retaining ring pressure may cause uneven stress distribution on the wafer surface during the polishing process, affecting the flatness and polishing quality of the wafer. Polishing pressure is a key factor affecting the surface roughness of the wafer. Too much polishing pressure will cause the wafer to be over-polished, and too little polishing pressure will cause insufficient polishing. By precisely controlling the polishing pressure of each partition, more refined polishing control can be achieved to achieve the required flatness, smoothness, and rework effect.

[0053] The EPD technology here can be implemented through software control, and the software can integrate eddy current endpoint detection, optical endpoint detection and / or motor torque endpoint detection functions to meet the needs of various processes. During the polishing process of the wafer, the wafer parameters on the wafer surface can be monitored in real time through the endpoint detection technology to stop the polishing process in time when the predetermined flatness and thickness are reached. The endpoint detection technology can avoid wafer defects caused by excessive or insufficient polishing, and is the key to achieving global flatness of the wafer.

[0054] As mentioned above, in an optional embodiment, the endpoint detection technology of the wafer may include an eddy current endpoint detection method and / or an optical endpoint detection method and / or a motor torque endpoint detection method.

[0055] The eddy current endpoint detection method detects the thickness of the metal layer on the surface of the wafer based on the eddy current detection principle. When a metal conductor is placed in a changing magnetic field, or moves in a magnetic field to cut magnetic lines of force, a vortex-shaped induced current will be generated in the conductor. This current is called eddy current. The eddy current endpoint detection method uses an eddy current sensor to monitor the eddy current changes caused by the metal layer on the surface of the wafer to achieve accurate measurement of the thickness of the metal layer.

[0056] The optical endpoint detection method detects the film thickness on the surface of the wafer through the optical detection principle. The optical detection principle uses a certain wavelength of light to illuminate the surface of the wafer, and obtains the film thickness of the wafer by analyzing the reflected wavelength. In an optional embodiment, the goodness of fit can be set, and the goodness of fit is the degree of fit between the actual measured reflection wavelength curve and the wavelength curve calibrated by the machine. In some embodiments, the lower limit of the goodness of fit can be set to 0.98. When the goodness of fit of the measurement point is lower than the lower limit, it is judged to be invalid, and re-measurement or selection of new measurement points is performed until the goodness of fit is not lower than the lower limit.

[0057] The principle of the motor torque endpoint detection method is to detect the change of motor torque during the polishing process to achieve the stop of the wafer polishing process. By installing a torque sensor on the motor shaft of the polishing head, analyzing the change in the motor torque reading, it is determined whether the polishing process is close to the end point. In the motor torque endpoint detection method, at the beginning of polishing, the film thickness on the surface of the wafer is thicker, and the friction between the polishing disc and the wafer is larger. At this time, the motor needs to output a larger torque to maintain the rotation of the polishing disc; as the polishing proceeds, the film is gradually removed, the friction decreases, and the motor torque also decreases; when the film reaches the expected film thickness, the friction reaches the expected value, and the motor torque reaches the set threshold, it can be considered that the polishing end point has been reached. It can also be understood that different film layers of the wafer have different friction coefficients on the polishing disc during polishing. When the polishing head passes through different film layers of the wafer, the motor torque will change. By detecting these changes in real time, the end point of the polishing process can be accurately determined. The motor torque endpoint detection method can ensure the accuracy and efficiency of the wafer multilayer film polishing process by real-time monitoring of torque changes.

[0058] In some embodiments, two or more of the aforementioned methods can be combined to perform polishing endpoint detection, and cross-validation can be used to ensure that the film thickness on the wafer surface reaches the expected value. In an optional embodiment, at least two data points can be detected, and the data points can include two or more of the eddy current data, optical data, and motor torque data, and compared with the corresponding film thickness data to determine the remaining thickness of the polished wafer. When it is detected that the remaining thickness of the polished wafer reaches the expected film thickness, the wafer polishing equipment stops polishing at the polishing endpoint. This method of automatically stopping polishing can avoid the problem of excessive polishing causing wafer damage or reduced wafer surface quality, improve the accuracy of wafer polishing, reduce material waste, and improve overall efficiency.

[0059] The EPD stop endpoint detection has very high requirements on the stability of the wafer morphology. If the wafer morphology is not stable, insufficient or excessive grinding removal may occur in different radius partitions, forming ring-shaped residues. Especially for precision nano-scale processes, the grinding rate corresponding to each radius partition must be more consistent, which makes it difficult to achieve real-time adjustment of the partition pressure.

[0060] In this case, in order to re-polish the wafer to adjust the film layer in each area of ​​the wafer to meet the process requirements, a partition rework method is developed and extended by dynamically adjusting the model partition operation to lower the usage threshold and meet the CMP process design of the composite film layer.

[0061] In step III, the wafer parameters of all partitions of the wafer are detected to determine whether the wafer parameters of all partitions of the wafer meet the standards. If the wafer parameters of all partitions meet the standards, proceed to step V; if the wafer parameters of all partitions or some partitions do not meet the standards, proceed to step IV.

[0062] In an optional embodiment, the wafer parameters may include film thickness and / or other parameters, such as surface flatness. In an optional embodiment, a surface profiler may be used to measure the surface flatness and profile of the wafer after polishing. The film thickness here is the film thickness after CMP primary polishing and grinding.

[0063] In actual processing, the wafer surface may have uneven thickness, and the film thickness in different areas may be different. After the primary polishing of the wafer, some areas of the wafer surface may have too much removal or some areas may have insufficient removal, resulting in the wafer surface still being uneven and unable to achieve the desired wafer morphology. By performing zoning inspection on the wafer, more precise polishing control can be provided to ensure the polishing uniformity of different areas of the wafer and achieve higher polishing accuracy.

[0064] In different embodiments, the method of wafer partitioning is not limited, and a suitable wafer partitioning method can be selected according to different process steps or wafer types. In the current embodiment, the wafer can be divided into a number of annular partitions according to different radius intervals. Since the wafer polishing stop does not take into account the situation of each partition in the primary polishing step, it is possible to consider re-inspecting and reworking each partition to improve product quality.

[0065] The wafer partition parameter here can be the wafer thickness. When detecting the film thickness of each partition of the wafer, the measurement principle may include the aforementioned eddy current detection principle and / or optical detection principle. It should be noted that the aforementioned motor torque measurement principle does not directly involve measuring the film thickness of the wafer, but judges whether the polishing is stopped according to the change of the motor torque during the polishing process. Therefore, compared with the motor torque measurement principle, the eddy current detection principle and / or optical detection principle are more suitable for the wafer partition detection film thickness. In the eddy current detection principle, the conductivity of different regions can be used to distinguish different wafer partitions, and the film thickness of each partition can be measured. In the optical detection principle, optical detection technology can realize the partition detection of the wafer by scanning different regions and analyzing the reflection spectrum.

[0066] In an optional embodiment, an upper specification limit, an upper control limit, a lower control limit, and a lower specification limit may be set. The upper specification limit and the lower specification limit may be the maximum and minimum acceptable values ​​of the film thickness of the wafer. If the measured value of the film thickness of the wafer exceeds the upper specification limit or is less than the lower specification limit, the wafer may be judged to be unqualified. If the film thickness is within the range of the upper control limit and the lower control limit, it can be considered that the polishing process of the wafer is in a controlled state. If it exceeds the range of the upper control limit and the lower control limit, it indicates that there may be anomalies or variations in the polishing process of the wafer, which requires investigation by the operator.

[0067] According to some embodiments, after the first polishing formula is read in to perform primary polishing on the wafer, the wafer needs to be partitioned to detect the film thickness. When the regional film thickness does not meet the set expected film thickness, the area needs to be reworked for secondary polishing, while the area that meets the standard does not need to be reworked, so as to avoid over-polishing or insufficient polishing of some areas on the wafer surface. In addition, due to rotation, the center and edge of the wafer may have different removal rates, so it is easier to detect and correct deviations in time by adjusting the polishing pressure in real time by region, thereby ensuring the quality of the wafer. In an optional embodiment, when judging whether the film thickness of the wafer parameters of the partitioned wafer meets the standard, a target thickness can be set. When the measured value of the film thickness reaches the target thickness, it is considered that the film thickness of the partitioned wafer meets the standard.

[0068] In step III, as mentioned above, the principle of measuring the film thickness of the partition of the wafer may include the eddy current detection principle and / or the optical detection principle. Since after the primary polishing, the under-polished annular area remains in the film layer of the same material (such as silicon dioxide), the film thickness measurement at this time is the thickness measurement of the film layer of the partition to be reworked.

[0069] The wafer parameters of each partition of the wafer are counted to determine whether the wafer parameters of all partitions of the wafer meet the standards. In an optional embodiment, the number of the partitions may be 5≤n≤12. In order to achieve the optimal effect of processing efficiency and processing quality, the number of the partitions may be selected as 7. Other numbers of partitions may also be selected in different embodiments.

[0070] If the wafer parameters of all the partitions of the wafer meet the standards, it can be determined that the polishing process of the wafer meets the expected process standards, and then proceed to unload the polished wafer and load the next wafer to be polished to continue polishing, that is, step V. If the wafer parameters of all or part of the partitions of the wafer do not meet the standards, the non-standard partitions of the wafer need to be reworked and polished once or multiple times to meet the expected process standards, that is, step IV. Steps IV and V are described below.

[0071] In step IV, a second polishing recipe is obtained according to wafer parameters of wafer partitions through a dynamic adjustment model, secondary polishing is performed on the substandard partitions of the wafer based on the second polishing recipe, and the process returns to step III.

[0072] If it is determined in step III that the wafer parameters do not meet the standards, proceed to step IV, and for the wafer after the partition inspection, automatically rework the wafer in different areas by reading the second polishing recipe, that is, perform secondary polishing on the wafer.

[0073] The dynamic adjustment model is applied to the process of stop in film, and the requirements of multi-process goods passing are met by dynamically adjusting the time and pressure. The present invention improves the dynamic adjustment model, develops and extends the partition rework using it. According to a specific embodiment of the present invention, when the amount of grinding removal of some partitions is insufficient or excessive during the use of EPD, the dynamic adjustment model is used in conjunction to adjust the pressure of the partitions, and the automatic partition rework function of balancing the pressure and time is realized.

[0074] The dynamic adjustment model can receive the wafer parameter detection results, analyze the collected data, and calculate the second polishing formula. In an optional embodiment, the dynamic adjustment model can have a built-in optimization algorithm, such as a machine learning model, etc. The dynamic adjustment model can also record all historical data and generate the best second polishing formula based on historical data and real-time feedback to achieve the best polishing effect. Through the dynamic adjustment mechanism provided by the dynamic model, the wafer polishing system can adapt to different wafer characteristics and polishing requirements to ensure high-quality polishing effects.

[0075] In an optional embodiment, the parameters of the first polishing formula and the second polishing formula may include polishing time, holding ring pressure, and pressure on each partition of the wafer. In an optional embodiment, the first polishing formula can be a standard formula pre-set according to historical experience and process requirements to ensure that the primary polishing of the wafer can be carried out as expected to achieve the required material removal rate and surface quality. However, due to the complexity of the wafer polishing process, the polishing effect may be different from expectations. Therefore, it is necessary to use a dynamic adjustment module to generate and adjust the second polishing formula in real time according to the detection results of the wafer parameters. The holding ring pressure can select a common formula pressure such as a standard formula to ensure that the wafer is not diced. Through dynamic adjustment, the polishing process of the wafer can be more flexible to adapt to different wafer characteristics and process requirements, thereby improving the polishing quality of the wafer.

[0076] In an optional embodiment, the dynamic model includes a calculation model for the polishing time, that is, the calculation formula for the polishing time in the parameters of the second polishing recipe may be:

[0077]

[0078] Where T is the polishing time, PreZ[i]PointMax is the maximum wafer parameter value of the Z[i] partition, i = 1, 2, ..., n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions of the wafer, and RR is the removal rate. Regarding the number of partitions, it can be, for example, 5, 7, 9, 11 or other suitable numbers. The Max function here is defined as the largest parameter among Max(a, b, c, d, e) = a, b, c, d, e.

[0079] For better understanding, the calculation formula of polishing time can be expressed as polishing time is equal to the ratio of the maximum removal amount screened out in all areas of the wafer to the removal rate. Here, the maximum removal amount can correspond to the area with the largest removal amount or the point with the maximum amount of removal required, and the RR removal rate is the material removal rate during the polishing process.

[0080] The dynamic adjustment model may include a calculation model for the polishing pressure of each partition of the wafer. That is, the calculation formula for the polishing pressure of each partition of the wafer in the parameters of the second polishing recipe may be:

[0081]

[0082] Wherein, P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum wafer parameter value of the Z[i] partition, i=1,2,…,n, Target is the target wafer parameter value, n is the number of wafer partitions, and the value of n is, for example, 5, 7, 9, 11 or other suitable values, k is the empirical coefficient, and Thk_Offset_Spec is the standard control line. Here, the If function is defined as If(((ad)>0),b,c), ad>0 is true and the result is b, ad>0 is false and the result is c; the Step function is defined as Step(a,b,c)(ab>c is 1, ab≤c is 0); the Max function is defined as Max(a,b,c,d,e)=the largest parameter among a,b,c,d,e. That is, the pressure of each partition = the default pressure of the current partition * (1-judgment (1-the maximum removal amount required for the current partition / the maximum removal amount required in all partitions>0) whether it is established, if it is established, the judgment result is 1, if not established, it is 0) * experience coefficient * the maximum removal amount required for the current partition / the maximum removal amount required in all partitions) * judgment (whether the maximum removal amount required for the current partition reaches the rework control line, if it reaches, it is 1, if not, it is 0). This formula comprehensively reflects the default pressure of each partition, the experience coefficient, the removal ratio of the current partition, and whether the partition reaches the rework control line. This formula can specifically correspond to the following situations:

[0083] (1) The current area is the area that requires the largest amount of removal. If function is 0, Step function is 1, and the final result is the pressure of the current area. Then the maximum amount of removal required by the current partition = the maximum amount of removal required in all partitions, P[i] = Z[i]_Press;

[0084] (2) The current area is not the area that requires the largest amount of removal, the If function is 1, the Step function is 1, and the final result is the current area pressure * (1-k * the amount of removal required in the current area / the maximum amount of removal required),

[0085]

[0086] (3) The maximum amount of removal required in the current area is less than 0, the Step function is 0, the final result is 0, and P[i] = 0.

[0087] By means of the present invention, the wafer parameters are detected in different zones and the second polishing formula is dynamically updated to perform secondary polishing, which realizes multi-zone automatic triggering of rework with automatic combined adjustment of time and pressure, thereby improving polishing efficiency, reducing the difficulty of rework, and improving product quality and production efficiency.

[0088] In an optional embodiment, the value of n can be selected according to the polishing process and the type of wafer. For example, the value of n can be set to 7, that is, seven partitions are divided on the polished wafer, and at least one film thickness measurement point is set in each partition. This can avoid the situation where there is only one measurement point and the film thickness of the wafer cannot be accurately determined once the data fails. In addition, there may be non-uniformity on the surface of the wafer, and the film thickness in different areas may vary. By setting measurement points in multiple partitions, the thickness of the film on the surface of the wafer can be better tested. By adjusting the pressure applied to each partition of the wafer in real time, the situation where the removal amount of each partition is insufficient or excessive can be avoided during the polishing process.

[0089] After polishing the sub-areas of the wafer that do not meet the standards, return to step III to once again check whether the wafer parameters of the sub-areas of the wafer meet the standards. Repeat steps III to IV until the wafer parameters of all sub-areas of the wafer meet the standards, and then proceed to step V.

[0090] In step V, the polished wafer is unloaded and the process returns to step I.

[0091] In step V, when the parameters of all wafer partitions meet the standards, the polished wafer can be unloaded and the process returns to step I to start a new round of wafer polishing.

[0092] Through this embodiment, it can be understood that when the end point stop detection of the primary polishing of the wafer shows insufficient or excessive partition grinding removal, the development, extension and joint application of the dynamic adjustment model can realize real-time adjustment of the partition pressure, perform dynamic rework of the partition, and realize the principle of automatic partition rework with automatic pressure / time balance, so as to meet the CMP process technology of the composite film layer, thereby reducing the yield loss and rework rate of the product.

[0093] This function of automatically reworking the entire wafer in different areas reduces manual intervention and improves processing efficiency. In addition, automatic reworking in different areas can accurately re-polish the substandard areas, avoiding repeated processing of the entire wafer, reducing material consumption and costs, and improving the overall quality of the product.

[0094] Figure 2 It is a schematic diagram of the polishing process of an embodiment of the wafer polishing method of the present invention.

[0095] exist Figure 2 In the embodiment of , a composite film layer wafer is schematically shown. Before polishing, the wafer includes a three-layer structure, which are a first film layer 10, a second film layer 20 and a silicon wafer substrate 30 from top to bottom. After the wafer is primary polished according to the first polishing recipe, the first film layer 10 is initially polished away to expose the second film layer 20 of the wafer, but the material of the first film layer 10 is not completely removed in a specific partition, and part of the material of the first film layer 10 still remains on the surface of the second film layer 20. After the wafer is secondary polished according to the dynamic adjustment model, the first film layer 10 on the surface of the wafer is completely removed, exposing the second film layer 20 of the complete wafer.

[0096] Figure 3 The structure block diagram of an embodiment of a wafer polishing device according to the present invention is schematically shown. The figure shows the structure and signal transmission of the wafer polishing device.

[0097] like Figure 3 As shown, the wafer polishing equipment includes at least a polishing module, an endpoint detection module, and a dynamic adjustment module.

[0098] The polishing module is responsible for polishing the wafer. In an optional embodiment, the polishing module performs primary polishing on the wafer according to the first polishing recipe sent by the dynamic adjustment module or performs secondary polishing on the wafer according to the second polishing recipe. The polishing module may include a polishing disc, a polishing head, and a liquid supply device. The polishing disc is covered with a polishing pad for polishing the wafer. The polishing head may be loaded with a wafer through a conductive rubber air film. The wafer is pressed against the polishing pad on the polishing disc by the polishing disc. The liquid supply device sprays polishing liquid onto the surface of the polishing pad. Under the chemical action of the polishing liquid, the relative movement of the polishing disc and the polishing pad causes the wafer to rub against the polishing pad to perform polishing.

[0099] The endpoint detection module can detect the wafer parameters of the wafer, and stop the polishing process through the endpoint detection technology to control the termination of the polishing process. At the same time, the endpoint detection module can also send the detection results of the wafer parameters to the dynamic adjustment module. The endpoint detection technology has been described in the previous article and will not be repeated here.

[0100] The dynamic adjustment module can receive the detection result of the wafer parameters sent by the endpoint detection module, generate a second polishing recipe, and send the first polishing recipe or the second polishing recipe to the polishing module.

[0101] Through the control polishing mechanism that combines the polishing module, endpoint detection module and dynamic adjustment module, dynamic optimization and adjustment of wafer polishing are achieved to ensure the accuracy of the polishing process and the quality of the wafers.

[0102] Figure 4 The structure block diagram of an embodiment of a data processing device according to the present invention is schematically shown.

[0103] As shown in the figure, the data processing device may include at least a memory and a processor. The memory may be used to store computer executable instructions or computer programs. In this embodiment, the memory may store a wafer polishing control algorithm and a film thickness detection algorithm, and save set polishing parameters and polishing recipes, such as polishing time, polishing pressure, etc. The processor may be used to execute the computer executable instructions or computer programs stored in the memory to implement the wafer polishing method of any of the aforementioned embodiments.

[0104] This embodiment realizes various calculation and control tasks in the wafer polishing control method through the coordinated work of the memory and the processor, ensuring high-quality and efficient processing of the wafer surface.

[0105] To achieve the aforementioned purpose, another aspect of the present invention further provides a computer-readable storage medium. The computer-readable storage medium can store computer-executable instructions or computer programs, and when the computer-executable instructions or computer programs are executed by a processor, the wafer polishing method of any one of the aforementioned embodiments is implemented.

[0106] It should be noted that the computer-readable storage medium of the present invention may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to, an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or component.

[0107] To achieve the aforementioned purpose, another aspect of the present invention further provides a computer program. The computer program may include computer executable instructions or a computer program, and when the computer executable instructions or the computer program are executed by a processor, the wafer polishing method of any one of the aforementioned embodiments can be implemented.

[0108] Computer program code for performing the operations of the present invention may be written in one or more programming languages ​​or a combination thereof, including, but not limited to, object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0109] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present disclosure. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some implementations as replacements, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0110] The above implementation methods are only used to illustrate the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. Ordinary technicians in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the embodiments of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the embodiments of the present invention, and the patent protection scope of the present invention shall be defined by the claims.

Claims

1. A wafer chemical mechanical polishing method, characterized in that: The polishing method comprises: Step I: loading the wafer to be polished; Step II: reading in a first polishing recipe, performing primary polishing on the wafer according to the first polishing recipe, and stopping the primary polishing by using an endpoint detection technology; Step III: Detecting wafer parameters of all partitions of the wafer, and determining whether the wafer parameters of all partitions of the wafer meet the standards. If the wafer parameters of all partitions meet the standards, proceed to step V; if the wafer parameters of all or some of the partitions do not meet the standards, proceed to step IV. Step IV: obtaining a second polishing recipe according to the wafer parameters of all the partitions by dynamically adjusting the model, performing secondary polishing on the partitions of the wafer that do not meet the standards based on the second polishing recipe, and returning to step III; Step V: Unload the polished wafer and return to step I.

2. The polishing method according to claim 1, characterized in that: The parameters of the first polishing recipe and the second polishing recipe include polishing time, retaining ring pressure, and polishing pressure on each partition of the wafer.

3. The polishing method according to claim 1, characterized in that: The endpoint detection technology includes an eddy current endpoint detection method and / or an optical endpoint detection method and / or a motor torque endpoint detection method. In the eddy current endpoint detection method, the eddy current detection principle is used to measure the film layer thickness of the wafer. In the optical endpoint detection method, the optical detection principle is used to measure the film layer thickness of the wafer.

4. The polishing method according to claim 1, characterized in that: The wafer parameters include the film thickness of the wafer.

5. The polishing method according to claim 4, characterized in that: The measuring principle of the film layer thickness of the partition of the wafer includes the eddy current detection principle and / or the optical detection principle.

6. The polishing method according to claim 5, characterized in that: The optical detection principle uses light of a certain wavelength to illuminate the surface of the wafer, and obtains the film thickness of the wafer by analyzing the reflected wavelength, wherein the lower limit of the goodness of fit is set to 0.98, and the goodness of fit is the degree of fit between the actually measured reflected wavelength curve and the wavelength curve calibrated by the machine. If the goodness of fit is lower than the lower limit, re-measure or select a new measurement point.

7. The polishing method according to claim 1, characterized in that: At least one measurement point is provided at each of the subareas of the wafer.

8. The polishing method according to claim 1, characterized in that: The dynamic adjustment model includes a calculation model for the polishing time, and the calculation model for the polishing time is: Wherein, T is the polishing time, PreZ[i]PointMax is the maximum value of the wafer parameter of the Z[i] partition, i=1,2,…,n, Target is the target wafer parameter value, Z[i] is the i-th partition of the wafer, n is the number of partitions of the wafer, and RR is the removal rate.

9. The polishing method according to claim 8, characterized in that: The dynamic adjustment model includes a calculation model of the polishing pressure of each partition of the wafer, and the calculation model of the polishing pressure is: Wherein, P[i] is the polishing pressure, Z[i]_Press is the default pressure of the current partition, PreZ[i]PointMax is the maximum wafer parameter value of the Z[i] partition, i=1,2,…,n, Target is the target wafer parameter value, n is the number of wafer partitions, 5≤n≤12, k is the empirical coefficient, and Thk_Offset_Spec is the standard control line.

10. The polishing method according to claim 1, characterized in that: The first polishing formula is a pre-set standard formula, and the second polishing formula is generated by the dynamic adjustment module according to the detection results of the wafer parameters and adjusted in real time.

11. A wafer polishing device, characterized in that: The wafer polishing device is used to perform the polishing method as described in any one of claims 1 to 10, and the wafer polishing device comprises: a polishing module, wherein the polishing module performs primary polishing on the wafer according to a first polishing recipe sent by the dynamic adjustment module or performs secondary polishing on the wafer according to a second polishing recipe, wherein the polishing module comprises a polishing disc, a polishing head, and a liquid supply device, wherein the polishing disc is covered with a polishing pad for polishing the wafer, the polishing head is loaded with the wafer, the wafer is pressed against the polishing pad on the polishing disc by the polishing disc, the liquid supply device sprays polishing liquid onto the surface of the polishing pad, and under the action of the polishing liquid, the relative movement of the polishing disc and the polishing pad causes the wafer to rub against the polishing pad so as to perform polishing; An endpoint detection module, wherein the endpoint detection module detects wafer parameters of the wafer and stops polishing by using an endpoint detection technology, and the endpoint detection module sends the detection result of the wafer parameters to the dynamic adjustment module; A dynamic adjustment module receives the detection result of the wafer parameter sent by the endpoint detection module, generates the second polishing recipe, and sends the first polishing recipe or the second polishing recipe to the polishing module.

12. A data processing device, characterized in that: The data processing device comprises: A memory, wherein the memory is used to store computer executable instructions or computer programs; A processor, wherein the processor is configured to implement the polishing method according to any one of claims 1 to 10 when executing the computer executable instructions or computer programs stored in the memory.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions or a computer program, and when the computer-executable instructions or the computer program are executed by a processor, the polishing method according to any one of claims 1 to 10 is implemented.

14. A computer program, characterized in that The computer program includes computer executable instructions or a computer program, and when the computer executable instructions or the computer program are executed by a processor, the polishing method according to any one of claims 1 to 10 is implemented.

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