JP2008277450A - Device and method for controlling polishing condition of cmp apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve polishing efficiency, reducing a running cost, and improve yield, by eliminating variation in residual film thickness of a wafer. <P>SOLUTION: A CMP apparatus 1 consists of a polishing recipe generating means 3 for generating an optimum polishing condition for polishing speed, polishing pressure, abrasives or the like of a wafer, a residual film thickness predicting means 4 which predicts a residual film thickness after polishing of the wafer polished under the polishing condition, a residual film thickness measuring unit 2 for measuring the residual film thickness of the wafer after polishing, and a computer 6 for controlling polishing the condition based on the measuring result of residual film thickness. The computer 6 comprises a calculation part 11 which calculates a difference between the measurement value of the residual film thickness and the predicted value, and a polishing condition correcting/changing part 13 which corrects/changes the polishing condition so that the calculated difference becomes minimum. Thus, correction/change of the polishing condition is performed in real time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polishing condition management apparatus and a polishing condition management method for a CMP apparatus, and more particularly, to a polishing condition management apparatus and a polishing condition management method for a CMP apparatus that optimize polishing conditions based on a measurement result of a remaining film thickness of a wafer. Is.

  Conventionally, when a wafer is polished by this type of CMP apparatus, a platen is rotated by a motor drive, and a wafer held on a carrier of a polishing head is supplied while supplying an abrasive onto a polishing pad attached to the platen. The film to be polished such as an oxide film or a metal film formed on the surface of the wafer is polished by pressing against the polishing pad while rotating.

In this CMP process, the thickness of the remaining film on the wafer surface (hereinafter referred to as the remaining film thickness) is measured with a remaining film thickness measuring machine and polished so that the remaining film thickness becomes a target value. In this case, the remaining film thickness is measured by the amount of displacement in the vertical direction of the polishing pad. Also, a method of performing CMP processing by simply feedback-controlling the measured value of the remaining film thickness, or monitoring the state during polishing of the wafer with a monitor, and depending on the result of this monitoring, the polishing state of the wafer to be polished next time There is also known a method of polishing to a target value by predicting (for example, see Patent Documents 1-3).
Japanese Patent No. 308285 Japanese Patent No. 3311864 JP 2005-518654 A

  In the conventional CMP process, when the remaining film thickness of the wafer is measured and polished, since the vertical displacement of the polishing pad is measured as the remaining film thickness, it is difficult to obtain a highly accurate measurement result. Also, in the case of CMP processing by simple feedback control of the residual film thickness measurement result, high residual film thickness measurement accuracy is not stably ensured, so that it can sufficiently cope with increasingly finer and highly integrated wafers. It has become difficult.

  On the other hand, when the polishing state of the wafer to be polished next time is predicted while monitoring the polishing state of the wafer on the monitor, the polishing condition is set for each module of the apparatus, that is, the rotation axis of each polishing head (hereinafter referred to as polishing). Therefore, the residual film thickness of the wafer is likely to vary between modules.

  As described above, in the conventional technology, it is difficult to accurately measure the remaining film thickness of the wafer, and the wafer remaining film thickness is likely to vary between modules, resulting in excessive polishing or insufficient polishing, resulting in a reduction in wafer polishing efficiency. . In addition, defective products are generated on the polished wafer, and the yield decreases. Furthermore, there is a problem that the running cost increases due to waste of consumables such as abrasives.

  Therefore, there is a technical problem to be solved in order to eliminate variations in the remaining film thickness of the wafer, increase polishing efficiency, reduce running costs, and improve yield, and the present invention solves this problem. For the purpose.

The present invention has been proposed to achieve the above object, and the invention according to claim 1 is a CMP apparatus for polishing a film to be polished formed on a wafer surface, wherein the polishing speed, polishing pressure, Polishing recipe preparation means for creating polishing conditions such that polishing conditions such as abrasives are optimized, residual film thickness prediction means for predicting the remaining film thickness after polishing of a wafer polished under the polishing conditions, and polishing A residual film thickness measuring machine that measures the residual film thickness of the subsequent wafer, and a computer that manages the measurement results of the residual film thickness and the polishing conditions; A calculation unit that calculates a difference from a predicted value; and a polishing condition correction / change unit that corrects / changes the polishing condition so that the calculated difference is minimized, and the correction / change of the polishing condition is corrected in real time. CMP apparatus configured to perform To provide a polishing condition management device.

  According to this configuration, the polishing conditions are prepared by the polishing recipe preparation means so that the polishing conditions such as the polishing speed, polishing pressure, and abrasives of the wafer are optimized, and the wafer to be polished under the optimal polishing conditions is prepared. The remaining film thickness after polishing is predicted by the remaining film thickness predicting means.

  Then, after polishing the wafer under the optimum polishing conditions, the remaining film thickness on the wafer surface is measured with a remaining film thickness measuring machine. After the next time, the difference between the measured value and the predicted value of the remaining film thickness is calculated by a calculation unit of a computer, and the polishing condition is corrected in real time by the polishing condition correction / change unit so that the calculated difference is minimized. Correct or change. Thus, the wafer is always polished under optimum polishing conditions, and the remaining film thickness of the wafer is accurately processed to the target value.

  The invention according to claim 2 is characterized in that the polishing recipe creating means is configured to provide optimum polishing conditions for each polishing step of the wafer, for each polishing axis of the CMP apparatus, for each platen, or for each combination of the polishing axis and the platen. A polishing condition management apparatus for a CMP apparatus according to claim 1 is provided.

  According to this configuration, optimum polishing conditions are created for each polishing step of the wafer, for each polishing shaft that is the rotation shaft of the polishing head, for each platen, or for each combination of the polishing shaft and the platen. Therefore, the wafer is polished under optimum polishing conditions according to individual polishing steps, polishing axes or platens.

  According to a third aspect of the present invention, the polishing recipe creating means creates an optimum polishing condition based on an approximate expression created from a past polishing history and data of a polishing model that the CMP apparatus itself has in advance. A polishing condition management apparatus for a CMP apparatus according to claim 1 or 2 is provided.

  According to this configuration, since the optimum polishing condition is created based on the approximate expression created from the past polishing history and the data of the polishing model that the apparatus itself has in advance, the past polishing history data and device Polishing conditions reflecting both specific polishing model data are created. This polishing model is a numerical formula obtained by quantifying the relationship between polishing parameters such as polishing pressure and polishing time and the polishing amount.

  According to a fourth aspect of the present invention, there is provided the polishing condition management apparatus for a CMP apparatus according to the first aspect, wherein the remaining film thickness predicting means predicts the remaining film thickness of the wafer based on an approximate expression created from a past polishing history. .

  According to this configuration, since the remaining film thickness of the wafer is predicted based on the approximate expression created from the past polishing history, the polishing history data is reflected in the predicted value of the remaining film thickness of the wafer.

  According to a fifth aspect of the present invention, the computer has a monitor unit for displaying a difference between the measured value and the predicted value of the polishing time, a polishing state of the wafer, and the like. Provide a management device.

According to this configuration, the difference between the measured value of the polishing time and the predicted value, the polishing state of the wafer, and the like are monitored by the monitor unit, so that the changing result data and the polishing state can be grasped in real time. .

  According to a sixth aspect of the present invention, in the computer according to the first or fifth aspect, the computer includes a polishing state determination unit that outputs a caution signal, a warning signal, and / or a polishing stop signal when the calculated difference is equal to or greater than a predetermined value. A polishing condition management apparatus for a CMP apparatus is provided.

  According to this configuration, when the calculated difference is equal to or greater than a predetermined value, a caution signal, a warning signal, and / or a polishing stop signal are output. Accordingly, when a change occurs in the polishing state, a notification to that effect is given, and in an emergency, the polishing process is immediately stopped.

  According to a seventh aspect of the present invention, the polishing condition correcting / changing unit is configured so that the polishing condition is changed for each polishing step of the wafer, for each polishing axis of the CMP apparatus, for each platen, or for each combination of the polishing axis and the platen. A polishing condition management apparatus for a CMP apparatus according to claim 1, wherein the polishing condition management apparatus corrects or changes the above.

  According to this configuration, the polishing condition is corrected and changed for each polishing step, for each polishing shaft, for each platen, or for each combination of the polishing shaft and the platen. Accordingly, the polishing conditions are corrected and changed to the optimum polishing conditions according to each polishing step, and the polishing conditions are corrected and changed to the optimum polishing conditions for each polishing axis, each platen, or each combination of the polishing axis and the platen.

  The invention according to claim 8 is a CMP apparatus for polishing a film to be polished formed on the wafer surface, and the polishing conditions are set so that the polishing conditions such as the polishing speed, polishing pressure, and polishing agent of the wafer are optimized. Polishing recipe creation step to be created, residual film thickness prediction step to predict the residual film thickness after polishing of the wafer polished under the polishing conditions, and residual film thickness measurement step to measure the residual film thickness of the polished wafer And a calculation step of calculating a difference between the measured value and the predicted value of the remaining film thickness, and a polishing condition correction / change step of correcting / changing the polishing condition so that the calculated difference is minimized, Provided is a polishing condition management method for a CMP apparatus that corrects and changes the polishing conditions in real time.

  According to this method, the polishing conditions are created so that the polishing conditions such as the polishing speed, polishing pressure, and abrasive of the wafer are optimized, and the remaining film after polishing of the wafer polished under the optimal polishing conditions Predict thickness. Then, after polishing the wafer under the optimum polishing conditions, the remaining film thickness on the wafer surface is measured. After the next time, the difference between the measured value and the predicted value of the remaining film thickness is calculated, and the polishing conditions are corrected and changed in real time so that the calculated difference is minimized. Thus, the wafer is always polished under optimum polishing conditions, and the remaining film thickness of the wafer is smoothly processed to the target value.

  According to the first aspect of the present invention, the polishing conditions such as the polishing rate (polishing time) and the flow rate of the polishing agent are always maintained optimally, thereby eliminating excessive polishing and insufficient polishing, and causing variations in the remaining film thickness of the wafer. It can be eliminated, and the polishing efficiency can be improved and the running cost (such as waste of abrasives) can be reduced. In addition, since the number of defective products is reduced as compared with the prior art, the yield can be improved.

  According to the second aspect of the present invention, the wafer can be polished under the optimum polishing conditions according to each polishing step, polishing axis, or platen. Therefore, in addition to the effect of the first aspect, the remaining film thickness of the wafer is targeted. The value can be polished more efficiently.

  In the invention described in claim 3, since the polishing conditions reflecting the past polishing history and the data of the polishing model unique to the apparatus can be obtained, in addition to the effect of the invention described in claim 1 or 2, the remaining film thickness of the wafer is reduced. It is possible to polish more accurately to the target value.

  Since the invention according to claim 4 predicts the remaining film thickness of the wafer based on the polishing history data, in addition to the effect of the invention according to claim 1, the reliability of the predicted value of the remaining film thickness increases. Has merit.

  According to the fifth aspect of the invention, since the changing result data and the polishing state can be grasped in real time, in addition to the effect of the first aspect of the invention, it is easily confirmed whether or not the polishing of the wafer is proceeding appropriately. can do.

  The invention according to claim 6 can immediately notify when an abnormality occurs in the polishing state of the wafer, and in particular, since the polishing process can be stopped immediately in an emergency, in addition to the effect of the invention according to claim 1 or 5 It is possible to prevent the wafer from being polished in an abnormal state.

  The invention according to claim 7 can be corrected and changed to the optimum polishing condition for each polishing step, for each polishing shaft, for each platen, or for each combination of the polishing shaft and the platen. In addition to the effect, it is possible to more effectively suppress the variation in the residual film thickness of the wafer between a plurality of polishing steps, between polishing axes, and / or between platens.

  In the invention according to claim 8, the polishing accuracy of the remaining film thickness of the wafer is improved by always maintaining the polishing conditions such as the polishing rate (polishing time) and the flow rate of the polishing agent optimally. Variations can be suppressed, and high polishing efficiency and running costs (such as waste of abrasives) can be saved. In addition, since the number of defective products is reduced as compared with the prior art, the yield of the wafer can be improved.

  The present invention provides a CMP apparatus for polishing a film to be polished formed on a wafer surface in order to achieve the objects of eliminating variations in the remaining film thickness of the wafer, increasing polishing efficiency, reducing running costs, and improving yield. A polishing recipe preparation means for preparing the polishing conditions so as to optimize the polishing conditions such as the polishing speed, polishing pressure, and abrasive of the wafer, and the remaining film thickness after polishing of the wafer polished under the polishing conditions. A remaining film thickness predicting means for predicting, a remaining film thickness measuring device for measuring the remaining film thickness of the polished wafer, and a computer for managing the measurement result of the remaining film thickness and the polishing conditions, The computer includes a calculation unit that calculates a difference between the measured value and the predicted value of the remaining film thickness, and a polishing condition correction / change unit that corrects and changes the polishing condition so that the calculated difference is minimized, Correction of the polishing conditions It was achieved by carrying out the change in real time.

  A preferred embodiment of the present invention will be described below with reference to FIGS. In this example, the optimum polishing conditions are created and the remaining film thickness of the polished wafer is predicted. After the wafer is subjected to CMP processing, the remaining film thickness of the polished wafer is measured for each module, and the remaining film thickness is measured. The measured value of the film thickness is compared with the predicted value to determine the difference between the two, and the polishing conditions are corrected and changed in real time as much as possible so that this difference is minimized.

  Polishing history data such as a polishing time and a polishing amount acquired in the polishing process of the wafer is managed for each polishing axis and / or platen, and is used when creating polishing conditions. The predicted value of the remaining film thickness can be calculated based on an approximate expression created from past polishing history data. All or some of a plurality of polishing conditions, detection results, polishing conditions, and the like may be arbitrarily selected and constantly monitored by the monitor unit.

As shown in FIG. 1, the CMP apparatus 1 includes a remaining film thickness measuring device 2, a polishing recipe creating means 3, a remaining film thickness predicting means 4, a polishing unit 5, a computer 6, and the like. The remaining film thickness measuring device 2 measures the remaining film thickness of the polished wafer. Further, the polishing recipe creation means 3 creates the polishing conditions so that the polishing conditions such as the polishing rate of the wafer, the polishing pressure, and the polishing agent are optimized.

  The polishing recipe creating means 3 creates an optimum polishing condition with reference to the past polishing history for each polishing step, for each polishing shaft, for each platen, or for each combination of the polishing shaft and the platen.

  Further, the polishing recipe creating means 3 is configured to obtain optimum polishing conditions based on both or one of the data based on the approximate expression created from the past polishing history and the data of the polishing model that the CMP apparatus 1 itself has in advance. Can be created.

  For example, FIG. 5A is a graph of a polishing model in which the relationship between the polishing time and the polishing amount shown for each polishing pressure is quantified and digitized. FIG. 5 (b) is a polishing based on FIG. 5 (a) in which the relationship between the polishing time and the remaining film amount shown for each polishing pressure, obtained when the film thickness before polishing is 280 nm, is quantified and digitized. It is a graph of a model. Based on these polishing models, the planned polishing amount is calculated.

  In this case, the latest data of the polishing history data can be weighted and used.

  The remaining film thickness predicting means 4 predicts the remaining film thickness after polishing of the wafer polished under the polishing conditions. The residual film thickness of the wafer can be predicted based on the approximate expression created from the past polishing history. The function of the remaining film thickness predicting means 4 can be shared by the polishing recipe creating means 3.

  The polishing unit 5 is a CMP apparatus main body for polishing a wafer. As shown in FIG. 2, the rotating shaft 8A of the platen 8 is rotated by a motor 7 and the polishing pad 9 adhered to the platen 8 is used. While supplying a polishing agent (not shown) to the top, the polishing shaft 10A of the polishing head 10 is rotationally driven to rotate the wafer held by the polishing head 10, and the wafer is pressed against the polishing pad 9 to obtain the wafer. The polishing film on the surface is configured to be polished.

  The computer 6 manages the polishing conditions based on the measurement result of the remaining film thickness. The computer 6 includes a calculation unit 11, a storage unit 12, a polishing condition correction / change unit 13, a monitor unit 14, a polishing status determination unit 15, and an apparatus control unit 16. The calculation unit 11 calculates a difference between the measured value and the predicted value of the remaining film thickness. The storage unit 12 stores the management condition of the polishing conditions and other data based on the measurement result of the remaining film thickness.

  Further, when the calculated difference is equal to or greater than a predetermined value, the polishing condition correction / change unit 13 corrects / changes the polishing condition so that the difference is minimized. Furthermore, the monitor unit 14 displays the difference between the measured value and the predicted value of the remaining film thickness and the polishing state of the wafer. In addition, when the calculated difference is equal to or greater than an allowable value, the polishing state determination unit 15 outputs a caution signal, a warning signal, and / or a polishing stop signal. Furthermore, the apparatus control unit 16 has a function of controlling the operation of each part of the CMP apparatus 1 mainly based on various command signals.

  The polishing condition management method according to this embodiment is managed based on the measurement result of the remaining film thickness of the wafer and the expected result before polishing. The expected result is a value set by obtaining an appropriate polishing time for the wafer.

  When polishing end point detection (not shown) is used, the end point detection result is managed in addition to the measurement result and the expected result before polishing. The detection principle of the polishing end point detection means is not particularly limited. For example, a method of detecting torque fluctuations of the driving motor of the polishing head 10 or the platen 8, or a method of optically detecting the remaining film thickness, an eddy current Any method may be used.

The polishing condition management apparatus 11 determines the thickness of a film to be polished such as a metal film or an oxide film formed on a polished wafer for each module, that is, for each polishing shaft 10A, for each platen 8, or for each polishing shaft 10A. Measurement is performed for each combination of the platens 8, the measured values are compared with predicted values, and polishing conditions are corrected and changed in real time as much as possible so that the difference is minimized.

  The polishing conditions include, for example, polishing time, polishing pressure (retainer pressure, zone pressure), polishing speed (rotation speed of platen 8 or polishing shaft 10A), wafer polishing temperature (temperature of polishing head, temperature of platen 8). The air float flow rate in the polishing head 10, the type, composition and flow rate of the abrasive are mentioned.

  Evaluation of the result of the measured remaining film thickness employs a difference or deviation between the absolute value of the measured value and the predicted value (deviation of the remaining film thickness with respect to the average remaining film thickness) for each polishing step or the polishing shaft 10A. Each platen 8 or each combination of the polishing shaft 10A and the platen 8 is evaluated.

  An example of the polishing condition management procedure according to this embodiment will be described in detail with reference to the flowchart of FIG. First, an optimum polishing condition is created by the polishing condition creating unit (step S1). In this case, the polishing conditions are created for each polishing step in consideration of useful information regarding the polishing conditions obtained from a wafer processing factory or a barcode reader.

  In creating the optimum polishing condition, the polishing condition is determined based on a calculation formula. In this case, an approximate expression of the relationship between polishing conditions such as polishing time and polishing amount is created from a large amount of polishing history information, and based on the result calculated by inserting specific data into this approximate expression, The optimum polishing conditions for the wafer (object to be polished) W are determined and adopted. FIG. 4A is a graph showing the relationship between the number of polished sheets and the amount of remaining film. In the figure, the slope of the graph, that is, the degree of change in the remaining film amount with respect to the number of polished wafers, is obtained based on the rate of increase / decrease in the remaining film amount for the latest i (an integer n equal to or greater than 1) wafer. From the next time onward, based on the degree of change in the remaining film amount, the remaining film amount of the (i + 1) th wafer is obtained, and the optimum polishing condition is determined by substituting the remaining film amount into an approximate expression. it can.

  FIG. 4B is a graph showing the relationship between the number of polished sheets and the amount of remaining film. Based on the degree of change in the remaining film amount, an approximate expression using a polynomial approximation curve is created, the remaining film amount of the wafer is obtained for the next (i + 1) th sheet, and the EPD time is substituted into the approximate expression. Then, the predicted value is calculated by extrapolation. Based on the expected value, the remaining film amount of the (i + 1) th wafer can be obtained, and the remaining film amount can be substituted into an approximate expression to determine and adopt the optimum polishing condition.

  After the next time, the remaining film thickness after polishing of the wafer polished under the above polishing conditions is predicted by the remaining film thickness predicting means 4 (step S2). The prediction of the remaining film thickness is completed until the remaining film thickness of the wafer is measured by the remaining film thickness measuring device in step S4. Thereafter, CMP processing is started in step S3. At this time, the polishing data acquired by the CMP process is managed for each polishing shaft 10A and / or for each platen 8, or for each polishing step.

  The polishing data includes polishing time, amount of remaining film by polishing processing type, EPD time, usage time and number of used consumables such as polishing pad 9 and polishing head 10, temperature of polishing pad 9, polishing head 10 Data such as temperature is included. These polishing data are stored and managed in the storage unit 12 as past polishing history, and are used as useful data when creating an optimum polishing recipe (step S4).

For example, the polishing time, the remaining film amount for each polishing processing type, and the EPD time in the polishing data are managed for each polishing step (for each polishing processing type) and for each platen 8. Further, the use time and / or the number of used polishes of consumables such as abrasives are managed for each polishing shaft 10A and / or for each platen 8. Further, the usage time or the number of used polishings of the polishing pad 9 and dresser is managed for each platen 8, and the usage time or the number of used polishings of the wafer retainer and polishing head 10 is managed for each polishing shaft 10A. In this embodiment, the polishing temperature of the wafer is also managed for each polishing shaft 10A and / or for each platen 8. For example, the temperature of the polishing pad 9 is managed for each platen 8, and the temperature of the polishing head 10 is managed for each polishing shaft 10A.

  Thereafter, the remaining film thickness of the wafer is measured by a remaining film thickness measuring machine in step S5. In this case, a metal film residual film thickness measuring machine or an oxide film residual film thickness measuring machine or the like is used depending on the type of film to be polished. Either a wire method or an eddy current method may be used.

  After the next time, in step S6, the progress of the CMP process, that is, the change state of the wafer polishing surface, the polishing temperature, and the like are confirmed on the monitor unit 6 while being displayed in real time. In this embodiment, the confirmation screen is divided into three ways for confirmation. On the confirmation screen 1, the result of calculating the difference between the predicted value of the remaining film thickness and the measured value by the calculation unit 11 is confirmed.

  Further, on the confirmation screen 2, the use time or the number of used polishes of consumables such as an abrasive and a polishing pad is monitored for each apparatus (polishing shaft 10A or platen 8), and the predetermined value preset for each apparatus is Check whether the usage time or the number of used polishing sheets is not shifted.

  Furthermore, on the confirmation screen 3, while monitoring the polishing temperature of the wafer measured by the temperature sensor, that is, the temperature of the polishing pad or the temperature of the polishing head, the measured temperature deviates from a predetermined value set in advance for each apparatus. Check if it exists.

  From the next time onward, the normality or abnormality of the polishing is evaluated and determined based on the deviation value between the result value and the predicted value and the variation in the result value (step S7). This evaluation is determined by the polishing state determination unit 15 for each polishing step and for each polishing shaft 10A and / or for each platen 8. In this embodiment, the evaluation is divided into three, “no abnormality”, “attention state”, and “warning state”.

  That is, evaluation is performed in three stages depending on whether a deviation value between the result value and the predicted value or a variation value of the result value is larger than a predetermined allowable value or a warning value. A corresponding signal is output to the outside or each part of the apparatus. For example, if it is less than the allowable value, it is determined that there is “no abnormality”, and polishing of the wafer from the next time is continued as it is.

  Also, if it is above the allowable value and below the warning value, it is determined that it is in “attention state”, and an attention signal (alarm) is generated to notify the operator. Further, if the value is greater than or equal to the warning value, it is determined that the state is “warning state”, and a warning signal (alarm) is generated and notified to the operator. When the deviation value between the result value and the predicted value exceeds a predetermined range, the approximate expression is changed. Further, the evaluation method of the “attention state” and the evaluation method of the “warning state” can be combined and evaluated.

  As described above, according to the present embodiment, the polishing conditions are prepared by the polishing recipe preparation means 3 so that the polishing conditions such as the polishing rate, polishing pressure, and polishing agent of the wafer are optimized, and the remaining wafer after polishing is left. The polishing condition correction / change unit 13 corrects / changes the polishing condition in real time so that the difference between the measured value of the film thickness and the predicted value is minimized.

  For example, as shown in FIG. 5C, when the 30% polishing rate is low, the target remaining film amount is calculated in Step 10. Further, after obtaining the above approximate expression when the 30% polishing rate is low, in steps 11 and 12, the polishing time is extended until the target polishing rate is obtained while the 30% polishing rate remains low.

  In addition, since the film thickness measurement of the wafer W is performed after cleaning the wafer W, the corrected and changed polishing conditions are not always reflected in the wafer W polished after the first wafer W measured. This may be reflected in the wafer W polished after the second or more wafers.

  Therefore, polishing conditions such as polishing speed, polishing time, and abrasive flow rate can always be maintained optimally, so that the remaining film thickness of the wafer can be accurately polished to the target value and variations in the remaining film thickness of the wafer can be eliminated. Also, the polishing efficiency is improved. Further, since the use time of consumables such as the polishing pad 9, the polishing head 10, and the abrasive is shortened to the minimum necessary, the waste of consumables is eliminated and the running cost is reduced. Furthermore, since the generation of defective wafers due to excessive polishing or insufficient polishing is reduced, the yield of wafers can be greatly improved.

  In addition, optimum polishing conditions are created by referring to the past polishing history for each wafer polishing step, for each polishing shaft 10A, for each platen 8, or for each combination of the polishing shaft 10A and the platen 8. Thus, the wafer can be polished under optimum polishing conditions according to the individual polishing steps, the polishing shaft 10A or the platen 8, so that the remaining film thickness of the wafer can be more efficiently polished to the target value.

  Furthermore, when weighting the latest polishing history data with high information value, the wafer can be polished under the polishing conditions that place importance on the latest raw data, so that the polishing efficiency of the wafer is further improved.

  Furthermore, in creating polishing conditions, by using the approximate expression created from the past polishing history and the data of the polishing model that the apparatus itself has in advance, the past polishing history and the polishing model unique to the apparatus can be obtained. Since the wafer can be polished under the polishing conditions reflecting the data, the remaining film thickness of the wafer can be polished efficiently and accurately.

  Further, since the remaining film thickness of the wafer is predicted based on the approximate expression created from the past polishing history, an objective and highly reliable predicted value can be obtained.

  Further, since the difference between the measured value and the predicted value of the polishing time and the polishing state of the wafer can be monitored and grasped in real time on the screen of the monitor unit 14, it is easy to determine whether the polishing state of the wafer is good or bad during polishing. Therefore, the polishing conditions suitable for the specifications of the wafer and the polishing environment can always be maintained.

  Further, when the calculated difference value is equal to or larger than the allowable value, a caution signal is automatically output from the polishing state determination unit 15, and when it is equal to or higher than the warning value, the warning signal and the polishing stop signal are automatically output. Therefore, even if an abnormal polishing state occurs, it can be dealt with immediately and appropriately.

  In this embodiment, the polishing conditions are corrected and changed independently for each wafer polishing step, for each polishing shaft 10A, for each platen 8, or for each combination of the polishing shaft 10A and the platen 8. Therefore, optimum polishing conditions according to each polishing step can be obtained, and optimum polishing conditions can be obtained for each polishing shaft 10A, for each platen 8, or for each combination of the polishing shaft 10A and the platen 8. Thus, variations in the residual film thickness of the wafer can be eliminated between the polishing steps, between the polishing shafts 10A and / or between the platens 8.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified one.

The block diagram which shows one Example of this invention and shows the grinding | polishing condition management apparatus of CMP apparatus. The perspective view which shows the grinding | polishing part which concerns on one Example. The flowchart explaining the procedure of the grinding | polishing condition management which concerns on one Example. It is a graph which shows the relationship between the number of polish which concerns on one Example, and the amount of remaining films, (a) is a graph explaining the tolerance | permissible_range of remaining film amount, (b) is a graph explaining actual polishing time and estimated time. . FIG. 4 is a graph illustrating characteristics of a polishing model according to an embodiment; (a) is a graph illustrating a case where the amount of remaining film increases with time using the polishing pressure as a parameter; The graph explaining the case where a film | membrane amount reduces with time, (c) is a graph which shows the relationship between the residual film | membrane amount and polishing time when a grinding | polishing speed | rate changes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 CMP apparatus 2 Remaining film thickness measuring machine 3 Polishing recipe preparation means 4 Remaining film thickness prediction means 5 Polishing part 6 Computer (control means)
8 Platen 10 Polishing Head 11 Calculation Unit 12 Storage Unit 13 Polishing Condition Correction / Change Unit 14 Monitor Unit 15 Polishing Status Judgment Unit

Claims (8)

In a CMP apparatus for polishing a film to be polished formed on a wafer surface,
Polishing recipe creating means for creating polishing conditions so that polishing conditions such as polishing speed, polishing pressure, and abrasive of the wafer are optimized,
A residual film thickness predicting means for predicting a residual film thickness after polishing of a wafer polished under the polishing conditions;
A residual film thickness measuring machine for measuring the residual film thickness of the polished wafer;
It is composed of a computer that manages the measurement results of the residual film thickness and the polishing conditions,
Further, the computer calculates a difference between the measured value and the predicted value of the remaining film thickness, and a polishing condition correction / change unit that corrects / changes the polishing condition so that the calculated difference is minimized. With
A polishing condition management apparatus for a CMP apparatus, wherein the polishing condition is corrected and changed in real time.   The polishing recipe creating means creates optimum polishing conditions for each polishing step of the wafer, for each polishing axis of the CMP apparatus, for each platen, or for each combination of the polishing axis and the platen. The polishing condition management apparatus for a CMP apparatus according to claim 1.   The polishing recipe creation means creates an optimum polishing condition based on an approximate expression created from a past polishing history and data of a polishing model that the CMP apparatus itself has in advance. 3. A polishing condition management apparatus for a CMP apparatus according to 1 or 2.   2. The polishing condition management apparatus for a CMP apparatus according to claim 1, wherein the remaining film thickness predicting means predicts the remaining film thickness of the wafer based on an approximate expression created from a past polishing history.   2. The polishing condition management apparatus for a CMP apparatus according to claim 1, wherein the computer has a monitor unit for displaying a difference between the measured value and the predicted value of the remaining film thickness and a polishing state of the wafer.   The CMP apparatus according to claim 1, wherein the computer includes a polishing state determination unit that outputs a caution signal, a warning signal, and / or a polishing stop signal when the calculated difference is equal to or greater than a predetermined value. Polishing condition management device.   The polishing condition correction / change unit corrects / changes the polishing condition for each polishing step of the wafer, for each polishing axis of the CMP apparatus, for each platen, or for each combination of the polishing axis and the platen. The polishing condition management apparatus for a CMP apparatus according to claim 1. A CMP apparatus for polishing a film to be polished formed on a wafer surface,
A polishing recipe creating step for creating polishing conditions so that polishing conditions such as polishing speed, polishing pressure, and abrasive of the wafer are optimized,
A remaining film thickness predicting step for predicting the remaining film thickness after polishing of the wafer polished under the polishing conditions;
A residual film thickness measurement step for measuring the residual film thickness of the wafer after polishing;
A calculation step of calculating a difference between the measured value and the predicted value of the remaining film thickness;
A polishing condition correction / change step for correcting / changing the polishing condition so that the calculated difference is minimized, and
A polishing condition management method for a CMP apparatus, wherein the correction and change of the polishing conditions are executed in real time.

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