Method for chemical-mechanical polishing of a substrate semiconductor wafer
Patent Information
- Application Number
- PCT/EP2026/054557
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-25
- Filing Date
- 2026-02-19
- Publication Date
- 2026-09-03
Smart Images
Figure EP2026054557_03092026_PF_FP_ABST
Abstract
Description
[0001] 202400001 / HA
[0002] 1
[0003] Method for the chemical-mechanical polishing of a substrate semiconductor disk
[0004] Technical field
[0005] The invention relates to a method for chemically-mechanically polishing at least one substrate semiconductor disk by means of a polishing device comprising at least one polishing head which includes at least one pressure chamber.
[0006] State of the art and technical task
[0007] A prior art method for the chemical-mechanical polishing of semiconductor wafers or substrate semiconductor wafers is described in document [document name missing].
[0008] US 10,654,145 B2 described, known, in which the change of the removal profile is made depending on the polishing cloth temperature, the data for this being taken from previous polishing processes, and is carried out by controlling the pressure in the polishing head pressure chambers or alternatively the rotational speed of the polishing head or the polishing cloth.
[0009] In general, some methods known from the prior art have in common the characteristic that the setting of the polishing pressure at the beginning of the polishing process is not adapted to the substrate semiconductor disk to be polished, including relevant influencing factors such as electrical resistance and actual geometry of the semiconductor disk, and the desired target geometry of this disk after polishing.
[0010] In the prior art method described above, for example, the polishing head pressures are set depending on the polishing cloth temperature, which is intended to provide information about the removal profile of the semiconductor wafer. Thus, the removal profile is only indirectly considered, and the selected polishing head pressures could lead to the target geometry not being achieved. Furthermore, the polishing head pressure is only adjusted during the polishing process based on the polishing cloth temperature data, and the optimal polishing head pressures may not be selected at the beginning of the process.
[0011] This can lead to long tuning times for the polishing systems, especially when changing the material being polished, which places different demands on the polishing system. 202400001 / HA
[0012] 2
[0013] Reducing tuning times through correct polishing head pressure settings at the beginning of the polishing process leads to an efficient and cost-effective polishing process for semiconductor wafers.
[0014] Description of the invention
[0015] The objective technical objective of the invention is therefore to provide a reliable polishing method which enables a representative setting of the polishing pressure for the current polishing process for the substrate semiconductor disk currently being polished, and which does not have the aforementioned disadvantages, or at least to a lesser extent.
[0016] The invention is based on the technical teaching that a reliable and representative setting of the polishing pressure for the current polishing process for the substrate semiconductor disk currently being polished can be achieved in a simple way to successfully achieve a predefinable spatial target contour of a first disk side of the substrate semiconductor disk to be polished, if the determination of the polishing pressure (or its individual polishing chamber pressures) is carried out by referring to a database of polishing recipes at least as a function of at least one previously determined spatial actual contour for the first disk side of the substrate semiconductor disk and a predefinable spatial target contour of the first disk side of the substrate semiconductor disk.Specifically, the invention recognizes that particularly reliable settings can be achieved when the polishing pressure to be set is determined according to the physical properties of the substrate semiconductor wafer to be polished by means of a parameterized polishing recipe function, the parameters of which were determined from polishing data stored in the database. The polishing data includes (historical) polishing chamber pressures of the individual pressure chambers, (historical) polishing pressures for the entire polishing head, (historical) target polishing removal profiles, and (historical) actual contours of wafers. Furthermore, the inventive method, with its reliance on the database of polishing recipes for parameterizing the polishing behavior of substrate semiconductor wafers with similar physical properties to set the current polishing pressure, enables...202400001 / HA.
[0017] 3
[0018] It is possible in a simple way to take into account different ablation behaviors for different doping levels of substrate semiconductor wafers.
[0019] According to a first aspect, the invention therefore relates to a method for the chemical-mechanical polishing of at least one substrate semiconductor disk by means of a polishing device comprising at least one polishing head, which includes at least one pressure chamber and a retaining ring at the outer edge, wherein at least one substrate semiconductor disk currently to be polished comprises a first disk side and a second disk side, wherein the method comprises at least one polishing sequence comprising the following steps:
[0020] I. Contacting the first disk side of the substrate semiconductor disk with a polishing cloth which is applied to a polishing plate of the polishing device,
[0021] II. Determining and setting a polishing pressure on the polishing head, wherein the polishing pressure is described by a polishing pressure distribution, wherein the polishing pressure is composed of at least one polishing chamber pressure of an associated pressure chamber, wherein the determination of the polishing pressure, in particular the determination of the at least one polishing chamber pressure, is carried out by referring to a database of polishing recipes at least as a function of at least one previously determined actual spatial contour for the first disk side of the substrate semiconductor disk and a predefinable target spatial contour of the first disk side of the substrate semiconductor disk, and
[0022] III. Applying the polishing pressure, in particular the at least one polishing chamber pressure, from step II) to the second side of the disc via the associated at least one pressure chamber of the at least one polishing head and the contacting of the retaining ring onto the polishing cloth.
[0023] The method according to the invention allows the advantages described above to be fully achieved in conjunction with the teaching of the invention. In particular, as already explained, it can be advantageously provided that the determination of the polishing pressure to be set, especially the current polishing pressure distribution, is carried out by means of a parameterized polishing recipe function.
[0024] 4
[0025] whose parameters were determined from historical polishing data stored in the database, including historical polishing chamber pressures of the individual pressure chambers, historical polishing pressures for the entire polishing head, historical target polishing material removal profiles, and historical actual contours of the discs. The advantage here is that no predefined, limited number of recipes need to be created; instead, the parameterized recipe function allows a suitable polishing pressure to be determined individually for the disc to be polished.
[0026] Furthermore, the method enables an automated, regular adaptation of the recipe function to possible changes by resetting the parameters using historical data.
[0027] In principle, the polishing recipe function can capture any correlations of parameters that are representative for the polishing process of the specific substrate semiconductor disk to be polished.
[0028] In particularly advantageous variants, the polishing recipe function can therefore provide a correlation between the polishing pressure, the actual contour, and the target polishing material removal profile. This allows the desired target contour of the substrate semiconductor wafer to be reliably achieved, reducing the number of wafers of insufficient quality and thus making the polishing process efficient and cost-effective. Preferably, the running times of the retaining ring on the polishing head are taken into account for the correlation of the polishing pressure and the material removal and grouped by running time, where the running times are described by the number of previous polishing cycles of the retaining ring. This allows, in particular, the run-in times on the polishing device to be reduced.
[0029] Preferably, the inventive method for chemical-mechanical polishing for determining the polishing pressure for a substrate semiconductor disk currently to be polished is based on a polishing recipe function comprising three main steps (however, the invention is by no means limited to the mandatory execution of these process steps):
[0030] Step 1: Classifying the substrates into groups with a recipe function
[0031] The substrates are preferably divided into groups according to similar electrical resistance, which exhibit similar polishing and abrasion behavior and 202400001 / HA
[0032] 5
[0033] so that they can be polished with a recipe function to a sufficiently good approximation.
[0034] Step 2: Preferably, historical polishing data, including the pressures from a first polishing chamber p, are used. x , the ATHK removal profile edgein the edge area and the geometric parameter of the edge waviness EW pre / EW post before and after polishing behavior as well as the desired edge waviness after polishing EW TGTThe function coefficients mi, ti, m2, ti for the parameterizable recipe function were determined using linear regression methods. In other words, these data represent the correlation between polishing pressure and material removal and can be grouped according to the operating times of the polishing cloth to avoid distorting the correlations between pressure and material removal over the cloth's lifetime (where the operating times are described in particular by the number of past polishing cycles of the retaining ring). Typical achievable polishing cycles are in the range of 0 to 50,000, with the initial run-in cycles between 300 and 700 preferably not being used for determining the linear regression. Typical grouping intervals according to polishing cycles are, for example, in the range of 50 to 200, preferably in the range of 90 to 110. The average of the resulting multitude of slope coefficients mi is preferably calculated.
[0035] The position coefficient ti is preferably calculated using the correlation between geometry parameter and material removal, so that in particular a change in the geometry parameter, which can be changed to negative or positive by polishing, from zero (EW pre = EW post ) lies in the middle of the pressures calculated using the recipe function. Due to the default position of the recipe function's value range, harmonization between the substrate groups is preferably achieved. When changing the substrate group to be polished, this harmonization allows the feedforward pressure determination to immediately select a suitable pressure. Without this harmonization, it is particularly necessary that the pressure be adjusted by the feedback control of the 202400001 / HA when changing the substrate group.
[0036] 6
[0037] The correction factor CF, which is multiplied by the polishing pressure, is adjusted. Adjustment using a feedback control algorithm can always introduce a time delay and may result in a longer run-in time for the polishing system each time the substrate group being polished is changed. Feedback control thus preferably compensates for the shortcomings of feedforward control. These preferred step variants significantly minimize the need for feedback control, especially when changing substrate groups, since the recipe functions of the individual substrate groups exhibit a harmonized position via their respective position coefficients ti. The availability of the polishing systems can be increased by reducing the run-in time when switching between substrates belonging to different groups.
[0038] The number of existing polishing recipes can be reduced by the continuous recipe function determined in this way, as there is no need to maintain extensive tables with pressure values for different substrate groups and input geometries. This particularly enables the implementation of new attribute-based groups, e.g., substrate edge type or polishing compound type. Additional dependencies between polishing pressure (or polishing chamber pressure), material removal profile, and geometry parameters can be represented by different versions of the function coefficients mi, ti, m2, and t2 determined above.By considering additional influencing factors, the number of possible function coefficients within a recipe function increases significantly. More attributes can be taken into account than in the current state, and these can preferably be easily stored in a function coefficient matrix and used to determine the polishing pressure depending on the polishing scenario. This allows for a more precise selection of the polishing pressure for each substrate semiconductor wafer with different attributes.
[0039] Step 3: The parameterized recipe function can be checked in test polishes, and if the results are insufficient, the function coefficients can be recalculated. 202400001 / HA
[0040] 7
[0041] This sequence of steps is preferably repeated for the different substrate groups from the first step.
[0042] As a result of this sequence of steps, the corresponding function coefficients and thus a precisely fitting recipe function can be obtained for each substrate group, which is preferably determined based on the actual edge waviness before polishing, the target edge waviness after polishing and the function coefficients to determine the appropriate pressure of the first polishing head chamber.
[0043] This generalized method can be applied to various geometric parameters if their changes can be described by the material removal profile (or the change in the material removal profile). The change in the material removal profile is directly related to changes in the zone pressure of each polishing chamber(s). The function coefficients mi, ti, m2, ti can be determined continuously and / or at regular intervals by a preferably automated evaluation of historical data and used for the polishing process.
[0044] In further preferred variants, the parameters of the polishing recipe function can be continuously adjusted, particularly automatically, at predefined intervals with regard to the polishing processes performed or at predefined time intervals, using a predefined number of recent historical polishing data points. These recent historical polishing data points originate from the same group of polishing material removal behavior within the database. Updating and maintaining the database further improves the reliability of setting a current polishing pressure.
[0045] In general, for other preferred variants, historical polishing data can be stored grouped according to historical wheels, and these groups can be classified according to physical, mechanical, or chemical properties that influence the polishing removal behavior. Since wheels with similar physical, mechanical, or chemical properties exhibit similar polishing removal behavior, a parameterized polishing recipe function can be determined for each group, thus benefiting the administrative and 202400001 / HA
[0046] 8
[0047] The computational effort of the recipe functions can be reduced without negatively affecting the quality of the polishing process.
[0048] In further preferred variants, the historical polishing data within the database for historical wafers can be classified into groups according to at least one physical property representative of the polishing removal behavior of substrate semiconductor wafers, in particular the electrical resistance of the respective substrate semiconductor wafer. Determining the polishing pressure for the current polishing process is achieved by specifically selecting from the group in whose classification range the specified value for the same physical property of the current substrate semiconductor wafer to be polished falls. This makes it possible, for example, to set polishing pressures (or...(Their individual polishing chamber pressures) make it possible to easily account for different ablation behaviors with different doping levels of substrate semiconductor wafers (since these differ in their electrical resistance depending on the amount of dopant). In further preferred variants, the groups can therefore be classified according to their electrical resistance. The advantage here is that the electrical resistance of the wafers is usually known, and thus no additional measurement is required to group the wafers based on a physical, mechanical, or chemical parameter.
[0049] In further preferred variants, the current polishing pressure can be adjusted depending on at least one of the following parameters: the actual contour of the first disk face of the at least one substrate semiconductor disk, the amount of dopant, the dopant type, and / or at least one polishing process property, including, but not limited to, the choice of the polishing compound composition and the amount of continuous polishing compound addition during the polishing sequence, the polishing cloth type, and the polishing head type. By considering further parameters influencing the polishing process, the polishing process can be modeled more precisely, and the polishing pressure determined on this basis enables a more accurate match to the target material removal profile and thus to the desired target contour of the disk. 202400001 / HA
[0050] 9
[0051] In further preferred variants, the polishing removal profile can be modified by controlling at least one of the pressure chambers of the at least one polishing head based on historical polishing data. This allows for high flexibility in setting the overall polishing pressure or its distribution across the polishing head, ensuring that the target removal profile is reliably achieved. The polishing process thus results in discs with precisely the desired contour, and fewer discs need to be rejected or repolished due to unsatisfactory geometry, reducing waste and improving the process capability of the polishing system.
[0052] In further preferred embodiments, the at least one polishing head can comprise several pressure chambers, preferably at least two, and more preferably a number from 5 to 7, which are arranged substantially concentrically within the at least one polishing head and are particularly ring-shaped. Preferably, the current polishing chamber pressure is continuously adjusted for each pressure chamber individually, with the corresponding polishing chamber pressure distribution superimposed on the total polishing pressure. This allows for a very precise and targeted adjustment of the polishing pressure, which is defined by a polishing pressure distribution, by flexibly adjusting the individual polishing chamber pressures within each chamber.
[0053] In further preferred embodiments, the at least one pressure chamber can comprise a first pressure chamber in which the pressure distribution of a current first polishing chamber pressure, in particular a first polishing chamber pressure distribution, is continuously adjusted. This adjustment can be based on a first geometric parameter that is representative of at least a first section of the first disc side (in particular, the edge region of the first disc side), wherein preferably at least a corresponding section of the second disc side is in contact with the first pressure chamber during the polishing process. Preferably, the first pressure chamber is annular in shape and arranged concentrically at the outermost region of the polishing head. This first geometric parameter can, for example, be a measure for the 202400001 / HA
[0054] 10
[0055] The waviness at the substrate wafer edge is represented. In particular, the determination of the waviness incorporates at least the characteristic value ESFQR and / or ESFQD, determined according to "SEMI M67 - Test Method for Determining Wafer Near-Edge Geometry from a Measured Thickness Data Array Using the ESFQR, ESFQD, and ESBIR Metrics," which are each determined for a substrate wafer edge segment with a segment section in an angular range of 3° to 9°, preferably 4° to 6°, and further preferably substantially 5°, wherein this process is repeated for all defined substrate wafer edge segments along a circumferential direction of the substrate wafer along the entire 360°. Finally, preferably, the results of substantially all substrate wafer edge segments are averaged, particularly arithmetically, to determine the first geometric parameter.
[0056] The first geometry parameter is preferably stored in the database and, depending on its value, assigned to at least one group of physical, chemical or mechanical properties.
[0057] In advantageous embodiments, at least one pressure chamber, preferably the first pressure chamber, can be annular in shape and arranged concentrically at the outermost point of the polishing head. This allows for targeted control of geometric parameters at the edge of the disc, while the geometry inside the disc remains essentially unchanged.
[0058] In further preferred embodiments, the at least one pressure chamber can comprise a second pressure chamber in which the pressure distribution of a current further polishing chamber pressure, in particular a second polishing chamber pressure distribution, is continuously adjusted. This adjustment can be made as a function of a second geometric parameter that is representative of at least a second section of the first disk side (in particular at least in the central region of the disk side), wherein preferably at least a corresponding section of the second disk side is in contact with the second pressure chamber during the polishing process, and the further pressure chamber is preferably arranged centrally on the polishing head. This second geometric parameter can, for example, be a measure of the global flatness of the first disk side of the substrate semiconductor disk or a measure of the scatter of the thickness distribution of the 202400001 / HA
[0059] 11
[0060] The disk is represented, in particular by the parameter GBIR according to the standard SEMI M59 - Terminology for Silicon Technology. The GBIR describes the range of variation of all distances between the disk surface and the idealized (smooth) second disk face of the disks or substrate semiconductor disks (i.e., the back side of the semiconductor disks or substrate semiconductor disks). It can be calculated as the difference between the largest and smallest distances of the disk surface to the idealized second disk face.
[0061] The second geometry parameter is preferably stored in the database and, depending on its value, assigned to at least one group of physical, chemical or mechanical properties.
[0062] The advantage here is that by specifically determining the pressure for a second pressure chamber in the polishing head, the target removal profile in the area of the second polishing chamber can be influenced, and the entire target contour of the disc can thus be achieved more precisely.
[0063] In further preferred variants, the setting of the current first and / or second polishing chamber pressure can be further dependent on the material type and / or system characteristics, in particular the number of pressure chambers in the at least one polishing head, and / or the polishing compound composition or quantity. Taking one or more of these additional factors into account, and in particular in addition to considering the waviness characteristic at the substrate disc edge, a precise, flexible, and rapid adjustment of the first (and / or the second, or a further pressure chamber formed in a further pressure chamber) polishing chamber pressure to the current requirements or polishing edge conditions and system boundary conditions can be easily achieved.
[0064] By considering additional influencing factors, the polishing process can be modeled more realistically, allowing for a more precise determination of the polishing pressures. This further improves the quality of the target contour of the polished discs.
[0065] Brief description of figure 202400001 / HA
[0066] 12
[0067] Figure 1 shows in summary the circuit diagram for a preferred embodiment of the chemical-mechanical polishing process according to the invention with its “feedforward” control (B) including upstream 3-step process (A) for the polishing process (C), as well as the “feedback” control (D).
[0068] Preferred embodiment of the method according to the invention
[0069] In the following, a preferred embodiment of the inventive method for chemically-mechanically polishing a substrate semiconductor disk currently to be polished by means of a polishing device comprising a polishing head is described.
[0070] The polishing head comprises five pressure chambers and a retaining ring at its outer edge. The first of the five pressure chambers is annular and arranged concentrically at the outermost point of the polishing head. The substrate semiconductor disk currently being polished has a first disk side and a second disk side.
[0071] The process for chemical-mechanical polishing of the substrate semiconductor disk currently being polished now comprises the following steps:
[0072] I. Contacting the first disk side of the substrate semiconductor disk with a polishing cloth which is attached to the polishing pad,
[0073] II. Determining and setting a polishing pressure at the polishing head, wherein the polishing pressure is described by a polishing pressure distribution, wherein, in the present embodiment, the determination of the polishing pressure using the polishing recipe function is limited to the first polishing chamber pressure of the associated first pressure chamber, and other pressure chambers are pressurized to a standard pressure regardless of the properties of the discs to be polished. The determination of the polishing pressure (in other words, determining the first polishing chamber pressure) is carried out by accessing a database containing the parameters of the polishing recipe function, which were derived from historical polishing data stored in the database. 202400001 / HA
[0074] 13
[0075] (see below in “3-step procedure”), where the polishing data includes historical polishing chamber pressures of the individual pressure chambers, historical polishing pressures for the entire polishing head, historical target polishing removal profiles and historical actual contours of discs, and
[0076] III. Applying the polishing pressure from step II) to the second side of the disc via the associated first pressure chamber of the polishing head and contacting the retaining ring with the polishing cloth.
[0077] In this embodiment, the polishing recipe function provides a correlation between the set polishing pressure, the actual contour, and the target polishing removal profile. The historical polishing data within the database is classified into groups for historical wafers according to a physical property that is generally representative of the polishing removal behavior of substrate semiconductor wafers, namely, in this embodiment, the electrical resistance of the respective substrate semiconductor wafer.
[0078] Setting the first polishing chamber pressure p x This is done depending on a first geometric parameter EW. pre , which is representative of a first section of the first side of the disc (specifically: for a section in the edge area of the first side of the disc), which (in addition to other areas or sections on the first side of the disc) undergoes a polishing removal ATHK during the polishing processedge This process involves a corresponding section of the second disc side being in contact with the first pressure chamber during the polishing process. In this exemplary embodiment, this first geometric parameter represents the characteristic value edge waviness EW, which is a measure of the edge geometry, i.e., specifically a measure of the waviness at the substrate disc edge.
[0079] 3-step process:
[0080] The preferred embodiment of the inventive method for chemical-mechanical polishing is based on the following procedure for determining the polishing pressure for a substrate semiconductor disk currently to be polished, based on a polishing recipe function according to three main steps: 202400001 / HA
[0081] 14
[0082] Step 1: Classifying the substrates into groups with a recipe function
[0083] The substrates are divided into groups according to similar electrical resistance, which exhibit similar polishing and abrasion behavior and can therefore be polished to a sufficiently good approximation using a recipe function.
[0084] Step 2: Using historical polishing data, including the pressures from a first polishing chamber p x , the ATHK removal profile edge in the edge region and the geometry parameter of the edge wave EW pre / EW post before and after polishing behavior as well as the desired edge waviness after polishing EW TGTThe function coefficients mi, ti, m2, ti for the parameterizable recipe function are determined using linear regression methods. The data for the correlation between polishing pressure and material removal are grouped according to the operating times of the retaining ring on the polishing head to avoid distorting the correlations between pressure and material removal over the lifetime of the polishing cloth. The average is then calculated from the resulting multitude of slope coefficients mi.
[0085] The position coefficient ti is calculated using the correlation between geometry parameter and material removal, so that a change in the geometry parameter, which can be changed to negative or positive by polishing, from zero (EW) pre = EW postThe pressure range calculated using the recipe function is located in the middle of the range. This default position of the recipe function's value range ensures harmonization between the substrate groups. When changing the substrate group to be polished, this harmonization allows the feedforward pressure determination to immediately select a suitable pressure. Without this harmonization, changing the substrate group requires adjusting the pressure via feedback control of the correction factor CF, which is multiplied by the polishing pressure. Adjusting via a feedback control algorithm always introduces a time delay, resulting in a longer run-in time for the polishing system each time the substrate group is changed. The feedback control thus compensates for the shortcomings of the feedforward control.In the step sequence of this preferred embodiment, the need for feedback control is significantly minimized, particularly when changing the substrate group, since the recipe functions of the individual substrate groups have a harmonized position via the respective position coefficient ti. The availability of the polishing systems can be improved by the reduced start-up time.
[0086] 15
[0087] The number of existing polishing recipes is increased when switching between substrates belonging to different groups. The continuous recipe function determined in this way reduces the number of existing recipes, as there is no need to maintain extensive tables with pressure values for different substrate groups and input geometries. This enables the implementation of new attribute-based groups, such as substrate edge type or polishing compound type. Additional dependencies between polishing pressure (or polishing chamber pressure), material removal profile, and geometry parameters can be represented by different versions of the function coefficients mi, ti, m2, and t2 determined above.By considering additional influencing factors, the number of possible function coefficients within a recipe function increases, but more attributes can be taken into account than in the current state. These can be easily stored in a function coefficient matrix and used to determine the polishing pressure depending on the polishing scenario. This enables a more precise selection of the polishing pressure for each substrate semiconductor wafer with different attributes.
[0088] Step 3: The parameterized recipe function is checked in test polishes and, if the results are insufficient, the function coefficients are recalculated.
[0089] This sequence of steps is repeated for the different substrate groups from the first step.
[0090] As a result of this sequence of steps, the corresponding function coefficients are obtained for each substrate group, and thus a precisely fitting recipe function is obtained which determines the appropriate pressure of the first polishing head chamber based on the actual edge waviness before polishing, the target edge waviness after polishing and the function coefficients.
[0091] Harmonization is achieved when each polishing recipe has the correct target value for the control parameter (in the present embodiment: ATHK). edge ) and is assigned. It turns out that a predicted polishing pressure, which in the present embodiment consists exclusively of the first polishing chamber pressure, is a better fit for the substrate semiconductor disk currently being polished than one determined via a feedback control202400001 / HA
[0092] 16
[0093] Selected polishing pressure. This "feedforward" approach reduces polishing pressures and jumps in the correction factor CF when polishing different substrate semiconductor wafer products. The correction factor CF can then be used to compensate for purely gradual changes in the polishing process, such as those caused by aging of the polishing cloth. By multiplying the polishing pressure p selected in the "feedforward" approach, the correction factor CF is increased. x The correction factor CF determines the actual polishing pressure p7 to be applied.
[0094] Figure 1 summarizes the circuit diagram for the preferred embodiment of the chemical-mechanical polishing process with its feedforward control (B) including a preceding 3-step process (A) for the polishing process (C), as well as the feedback control (D). The process further has the advantage that the feedforward approach according to the invention, which already enables a reliable and targeted adjustment of the polishing pressure at the polishing head, reduces the time lag of the feedback control as known from the prior art.
[0095] *****
Claims
202400001 / HA 17 Patent claims 1. A method for chemically-mechanically polishing at least one substrate semiconductor disk by means of a polishing device comprising at least one polishing head, which includes at least one pressure chamber and a retaining ring at the outer edge, wherein at least one substrate semiconductor disk currently to be polished comprises a first disk side and a second disk side, wherein the method comprises at least one polishing sequence comprising the following steps: I. Contacting the first disk side of the substrate semiconductor disk with a polishing cloth which is applied to a polishing plate of the polishing device, II. Determining and setting a polishing pressure on the polishing head, wherein the polishing pressure is described by a polishing pressure distribution, wherein the polishing pressure is composed of at least one polishing chamber pressure of an associated pressure chamber, wherein the determination of the polishing pressure, in particular the determination of the at least one polishing chamber pressure, is carried out by referring to a database of polishing recipes at least as a function of at least one previously determined spatial actual contour for the first disk side of the substrate semiconductor disk and a predefinable spatial target contour of the first disk side of the substrate semiconductor disk, and III. Applying the polishing pressure, in particular the at least one polishing chamber pressure, from step II) to the second disk side via the associated at least one pressure chamber of the at least one polishing head and the contacting of the retaining ring onto the polishing cloth.
2. Method according to claim 1, wherein the determination of the polishing pressure to be set, in particular the current polishing pressure distribution, is carried out by means of a parameterized polishing recipe function, the parameters of which were determined from historical polishing data stored in the database, wherein the polishing data are historical polishing chamber pressures of the individual pressure chambers, historical polishing pressures for the entire polishing head, 202400001 / HA 18 Includes historical target polishing removal profiles and historical actual contours of discs.
3. Method according to claim 2, wherein the polishing recipe function provides a correlation between the polishing pressure, the actual contour and the target polishing removal profile.
4. Method according to claim 3, wherein for the correlation of the polishing pressure and the material removal the running times of the retaining ring on the polishing head are taken into account and grouped according to running times, wherein the running times are described by the number of past polishing cycles of the retaining ring.
5. Method according to one of claims 2 to 4, wherein the parameters of the polishing recipe function are continuously, and in particular automatically, adjusted at predefinable intervals with regard to polishing processes carried out or at predefinable time intervals using a predefinable number of recent historical polishing data, wherein these recent historical polishing data originate from the same group of polishing removal behavior within the database.
6. Method according to one of claims 2 to 5, wherein the historical polishing data within the database for historical discs are classified into groups according to at least one physical property that is representative of the polishing removal behavior of substrate semiconductor discs, in particular according to the electrical resistance of the respective substrate semiconductor disc, wherein the determination of the polishing pressure for the current polishing method is carried out in the form of a specific selection from that group in whose classification value range the specified value for the same physical property of the current substrate semiconductor disc to be polished falls.
7. Method according to any one of claims 2 to 6, wherein the historical polishing data are stored grouped according to historical discs. 202400001 / HA 19 are and these groups are classified according to parameters that influence the polishing removal behavior.
8. Method according to claim 6 or 7, wherein the groups are classified according to electrical resistance.
9. Method according to one of the preceding claims, wherein the current polishing pressure is adjusted depending on at least one of the actual contour of the first disk side of the at least one substrate semiconductor disk, the amount of dopant, the dopant type and / or at least one polishing process property, including, but not limited to, the choice of the polishing agent composition and the amount of continuous polishing agent addition during the polishing sequence, the polishing cloth type and the polishing head type.
10. Method according to any one of claims 2 to 9, wherein a change in the polishing removal profile is effected by regulating at least one of the pressure chambers of the at least one polishing head based on the historical polishing data.
11. Method according to any of the preceding claims, wherein the at least one polishing head comprises several pressure chambers, preferably at least two, further preferably a number from the range of 5 to 7, which are in particular arranged substantially concentrically in the at least one polishing head and in particular are substantially ring-shaped, wherein A continuous adjustment of the current polishing chamber pressure with a current polishing chamber pressure distribution is carried out individually for each pressure chamber and is superimposed in total to the polishing pressure with the assigned polishing pressure distribution.
12. Method according to one of the preceding claims, wherein the at least one pressure chamber comprises a first pressure chamber in which a 202400001 / HA 20 Continuous adjustment of the pressure distribution of a current first polishing chamber pressure, in particular a first polishing chamber pressure distribution, is carried out, wherein the adjustment is made as a function of a first geometric parameter which is representative for at least a first section of the first disk side, in particular in the edge region of the first disk side, wherein preferably at least a corresponding section of the second disk side is in contact with the first pressure chamber during the polishing process.
13. Method according to claim 12, wherein the first pressure chamber is annular in shape and arranged concentrically at the outermost region of the polishing head.
14. Method according to one of the preceding claims, wherein the at least one pressure chamber comprises a second pressure chamber in which a continuous adjustment of the pressure distribution of a current further polishing chamber pressure, in particular a second polishing chamber pressure distribution, takes place, wherein the adjustment is made as a function of a second geometric parameter which is representative for at least a second section of the first disc side, in particular in the central region of the first disc side, wherein preferably at least a corresponding section of the second disc side is in contact with the second pressure chamber during the polishing process, wherein the second pressure chamber is arranged centrally on the polishing head.
15. Method according to one of claims 11 to 14, wherein the setting of the current first and / or second polishing chamber pressure is further dependent on the material type and / or system characteristics, in particular the number of pressure chambers in the at least one polishing head, and / or the polishing compound composition or quantity. *****