Double or single side machining apparatus

Abstract

The invention relates to a double- or single-sided machining machine comprising a preferably annular, lower first working disk and an upper counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other via a rotary drive, wherein a working gap is formed between the first working disk and the counter bearing element for machining flat workpieces on both or one side, wherein the double- or single-sided machining machine further comprises a machine base with feet by which the machine base rests on the floor of a production room in the assembled state of the double- or single-sided machining machine, wherein the machine base supports the first working disk and the counter bearing element, and wherein the feet have sensors for monitoring the alignment of the first working disk.

Description

[0001] The invention relates to a double- or single-sided machining machine comprising a preferably annular, lower first working disk and an upper counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other via a rotary drive, wherein a working gap is formed between the first working disk and the counter bearing element for machining flat workpieces on both or one side, wherein the double- or single-sided machining machine further comprises a machine base part with feet, with which the machine base part stands on a floor of a production room in the assembled state of the double- or single-sided machining machine, wherein the machine base part supports the first working disk and the counter bearing element.

[0002] For example, in double-sided machining centers, flat workpieces, such as wafers, are machined simultaneously on both sides. These machines have an upper and a lower working disk, between which a typically annular working gap is formed, in which the workpieces to be machined are guided during processing. The upper working disk is usually attached to an upper support disk, and the lower working disk is usually attached to a lower support disk. For machining, a relative rotation between the working disks is achieved by rotating at least one of the working disks, particularly together with its support disk. Double-sided machining centers are known in which so-called runner disks are guided in the working gap. The runner disks typically hold the workpieces to be machined in a floating manner within circular openings.A suitable kinematic system ensures that the rotor discs also rotate within the working gap as the working discs rotate relative to each other. This causes the workpieces to move along cycloidal paths within the working gap, resulting in a particularly uniform surface finish. The machining can be performed, for example, by grinding, lapping, or polishing. In double-sided polishing machines, for instance, multiple silicon wafers, such as more than ten with a diameter of 300 mm, can be processed simultaneously in this way.

[0003] The machining of workpieces in a given machining step should be carried out under the most stable possible load over time, with the load being distributed as homogeneously as possible across the entire surface of the machining disc. An ideal homogeneous distribution is achieved, in particular, when the lower machining disc is perfectly horizontal and the drive shafts of both discs are parallel, ideally coaxial. The alignment of the machining discs depends on a number of factors, such as the manufacturing tolerances of the individual components, in total. Another factor is the flatness of the disc surface. The more uneven the surface of the disc, the lower the resulting workpiece quality. The machine's installation location is also a factor. For example, an uneven installation surface leads to misalignment between the machining discs, which requires complex correction.Regarding manufacturing tolerances, every effort is made to minimize permissible manufacturing defects in individual components. The surface flatness of the work discs is improved through suitable dressing processes. To compensate for unevenness in the floor at the machine's installation site, height-adjustable feet on the machine base supporting the work discs are a known feature. Such feet may be equipped with damping.

[0004] The primary goal when adjusting the feet is to ensure the lower work disc is horizontally aligned. Once this is achieved, the upper work disc or a counter bearing element is aligned with the surface of the lower work disc, particularly with its drive shaft. However, this alignment, established during the machine's setup for operation, is not stable over an indefinite period but is subject to change due to various factors. For example, damping elements in the feet are not stable over time but lose elasticity, especially with age and extended use. Furthermore, the floor of a production area supporting the machine is typically not uniform, necessitating realignment if the machine is repositioned. Moreover, such a floor is often not stable over time either.This is particularly true for cleanroom floors with columns or those located on higher floors. Over time, changes in the floor surface can occur, affecting the alignment of the machining machine's working discs. The alignment of the working disc drive shafts is also influenced by loads, such as those from feet, which can lead to unforeseen changes in alignment.

[0005] Such changes in the alignment of the machining discs are not externally detectable but only become apparent as a deterioration in workpiece quality after the completion of a production process, despite consistent process parameters. While it is possible to identify a general change in the machining process by observing altered process parameters, such as the working gap, it is impossible to distinguish how and to what extent individual factors, such as the aging of process components like slurries or polishing pads, or a misalignment of the machining discs, contribute to the change in condition. Consequently, deviations from the ideal range of process parameters and machining disc alignment are often detected late, resulting in significant scrap.

[0006] Misalignment can result from both a tilting of the work discs relative to each other and a non-coaxial alignment of the work discs. A further problem arises with double- or single-sided machining centers where an upper work disc can be moved between a position above the lower work disc and a position pivoted away from it by means of a swivel arm. Here, on the one hand, the swiveling movement can cause an undesirable change in the alignment between the work discs when they are pivoted back to the position above the lower work disc. On the other hand, such machining centers often have an asymmetrical weight distribution due to the swivel arm arrangement, which further complicates the alignment of the work discs.This is especially true given the considerable total weight of such machines, exceeding 10 t, for example approximately 20 t.

[0007] The aforementioned misalignments lead to a deterioration in workpiece quality. Countermeasures can result in a reduction in the service life of work disc components, particularly more frequent dressing, reduced throughput, and consequently increased costs.

[0008] Based on the prior art described above, the invention aims to provide a double- or single-sided machining machine of the type mentioned above, with which workpieces can be machined reliably and cost-effectively with high quality and reduced scrap.

[0009] The invention solves the problem through the subject matter of independent claim 1. Advantageous embodiments can be found in the dependent claims, the description and the figures.

[0010] For a double-sided or single-sided machining machine of the type mentioned above, the invention solves the problem by providing the feet with sensors for monitoring the alignment of the first working disc.

[0011] The processing machine can be, for example, a polishing machine, a lapping machine, or a grinding machine. The workpieces being processed can be, for example, wafers. A working gap is formed between the first working wheel and a counter-bearing element, such as a simple weight or pressure cylinder in single-sided processing machines, or a second working wheel in double-sided processing machines. In this gap, the workpieces are processed on one or both sides. In a double-sided processing machine, the top and bottom of the workpieces can be processed simultaneously in the working gap. Accordingly, both working wheels can have a working surface that processes the workpiece surface. In contrast, in a single-sided processing machine, only one side of the workpiece is processed, for example, the underside, by the lower working wheel.In this case, only one working disc has a working surface that processes the workpiece surface. The counter bearing element then serves only to form a corresponding counter bearing for the processing by the working disc.

[0012] The workpieces can be mounted in a floating manner in openings of rotor discs arranged in the working gap for machining, in a manner known per se. During operation, the first working disc and the counter bearing element are driven to rotate relative to each other, for example, via a first and / or a second drive shaft and at least one drive motor. Both the counter bearing element and the first working disc can be driven to rotate, for example, in opposite directions. However, it is also possible to drive only one of the counter bearing element and the first working disc. For example, in a double-sided machining center, suitable kinematics can also cause the rotor discs to rotate through the working gap during this relative rotation, so that workpieces arranged in the rotor discs describe cycloidal paths in the working gap.For example, the rotor disks can have teeth on their outer and / or inner edges that engage with corresponding teeth, for example, on the first working disk. Such machines with so-called planetary kinematics are known per se.

[0013] The lower, first working disc can be ring-shaped. The upper counter-bearing element, or the second working disc, can also be ring-shaped. The first working disc and the counter-bearing element, for example, the second working disc, then have opposing, ring-shaped working surfaces, between which the ring-shaped working gap is formed. The working surfaces can be covered with a working material, such as polishing cloths. Any support discs holding the working discs can also be ring-shaped or at least have ring-shaped support sections to which the working discs are attached. More than one support disc per working disc can also be provided. The first working disc and / or the counter-bearing element can be single-layered or multi-layered. The same applies to a support disc that carries the first working disc or the counter-bearing element.

[0014] Temperature control channels can be formed in the first working disk and / or the counter bearing element and / or in a first support disk supporting the first working disk and / or a second support disk supporting the counter bearing element, through which a temperature control fluid, for example a temperature control liquid, is guided during operation to temperature control the respective components.

[0015] The machine base, which supports the first working disc and the counter bearing element, can be designed as a housing. It can also support a rotary drive for rotating the first working disc and / or the counter bearing element. Likewise, the machine base can support a pivoting arm, if provided, for pivoting the counter bearing element. The machine base can also support any first and / or second support discs, if provided.

[0016] According to the invention, the feet on which the machine base rests on the floor of a production area have sensors that monitor, in particular indirectly, the alignment of the lower first working disk. The feet can also include damping elements. As will be explained below, the sensors can be designed in different ways. The invention is based on the understanding that, for example, by monitoring a weight force acting on the feet and / or the vertical position of the feet, the correct alignment of the first working disk for optimal workpiece quality can be determined. Thus, the sensors in the feet make it possible to detect an undesirable deviation from a predetermined optimal alignment of the first working disk at an early stage, and therefore to identify the risk of deteriorating workpiece quality early on.to counteract this in a timely manner with suitable countermeasures in order to minimize rejects. The sensor feet according to the invention allow for reliable differentiation from other possible causes of reduced workpiece quality. For example, an operator can be alerted to a deviation of the alignment from a predetermined orientation, so that suitable countermeasures can be taken in a timely manner to further ensure the desired workpiece quality. Thus, the invention ensures in a simple and reliable manner that the workpiece quality is maintained at all times, even with the changes in influencing factors affecting the alignment of the first working disc described above. The alignment of the counter bearing element is generally adjusted depending on the alignment of the first working disc.For example, the upper counter bearing element can be connected to a drive shaft via a flexible connecting element, such as a curved-tooth coupling, so that it flexibly adapts to the orientation of the lower first working disc. Thus, if correct alignment of the first working disc is ensured, the desired alignment of the counter bearing element is also achieved.

[0017] In one embodiment, the counter bearing element can be formed by a preferably annular second working disk, with the working gap for machining flat workpieces from one or both sides being formed between the first and second working disks. Particularly when correctly aligned, the first and second working disks can be arranged coaxially to each other. The first working disk can be attached to a first support disk, which is also supported by the machine base, and / or the second working disk can be attached to a second support disk, which is also supported by the machine base.

[0018] In a further embodiment, the counter bearing element can be arranged on a pivot arm mounted on the machine base and pivoted relative to the first working disk. A rotary drive for the counter bearing element mounted on the pivot arm can be integrated into the pivot arm. As explained at the outset, particularly with such machine tools, which have an asymmetrical weight distribution on the machine base, there are special challenges regarding the alignment of the first working disk, especially the reliable maintenance of the correct alignment, which can be reliably addressed according to the invention.

[0019] In a further embodiment, the feet's sensors can include weight sensors that measure the weight force acting on each foot. This embodiment takes into account the weight distribution across the different feet of the machine base. Scales, for example, can be used as weight sensors. During the machine's setup process, the weight distribution across the feet can be adjusted so that the same weight force acts on all feet, and then the first working disc can be aligned. Alternatively, the first working disc can be aligned initially with any weight distribution between the forces acting on the feet. In both cases, the weight distribution acting on the feet after the setup process can be considered the default weight distribution, which is then monitored by the sensors.In particular, the sensors can measure the weight distribution after each production process, and these measurements can be compared with those from a previous production process and / or with values ​​assigned to the specified weight distribution, especially those measured against the specified weight distribution. This results in static monitoring of the alignment of the lower first working disc after each production process, particularly after the counter bearing element is disengaged from the first working disc. Even the slightest deviations from the original alignment of the first working disc will cause a change in the weight distribution on the feet that can be measured by the sensors.For example, if a limit deviation from the originally specified weight distribution is exceeded, a warning message can be issued to an operator and countermeasures can be taken manually or automatically to readjust the alignment of the first working disc for optimal workpiece quality.

[0020] In a further embodiment, the sensors can include optical sensors that optically measure the position of the feet, in particular their vertical position. These optical sensors can, for example, include laser sensors that measure the position of the feet, preferably via time-of-flight measurement. In particular, an optical transmitter, for example a laser, can be provided that directs optical radiation onto a reflector. Depending on the time of flight of the radiation from the transmitter to the reflector and to a receiver for the radiation, located, for example, at the transmitter's position, the distance between the transmitter and the reflector, and thus, for example, the vertical position of a support foot, can be measured. This embodiment takes advantage of the fact that a misalignment of the first working disc can lead to a change, for example, in the height of individual feet compared to other feet.This can be measured, so that, as explained above, suitable countermeasures can be taken to maintain the specified alignment for optimal workpiece quality.

[0021] The double- or single-sided machining center can also include an evaluation unit that receives the measurement data from the sensors. This evaluation unit can be configured to issue a warning signal if a deviation of the first working disc's orientation from a predefined orientation is detected. Based on such a warning signal, an operator can take measures to restore the optimal orientation of the first working disc. This could involve, for example, changing the position of the first working disc, such as a vertical, lateral, and / or tilting movement, and / or adjusting its feet, such as a vertical movement of the feet. Thus, changing the position of the first working disc could, for example, involve a vertical adjustment and / or a lateral adjustment.It can also involve tilting the first working disc, for example to correct a non-coaxial alignment of the rotation axes of the first working disc and the counter bearing element.

[0022] In a further embodiment, the evaluation unit can be configured to control the double- or single-sided machining center when a deviation of the first working disc's orientation from a predefined orientation is detected, so that the orientation of the first working disc again corresponds to the predefined orientation. With this embodiment, an automatic realignment can therefore occur when a deviation from the predefined orientation is detected, in order to maintain optimal workpiece quality at all times. For this purpose, the evaluation unit can control suitable adjustment devices with which the position of the first working disc and / or feet can be adjusted in the manner described above.

[0023] In a further embodiment, the first working disc and / or a first support disc carrying the first working disc and / or the feet can be provided with an adjustment device that can be controlled by the evaluation device so that the alignment of the first working disc corresponds again to the specified alignment.

[0024] In a particularly practical embodiment, the adjustment device can comprise at least one adjustment element, such as an adjustment wedge, which is movable translationally by means of an adjustment drive. This adjustment element allows the first working disc and / or a first support disc carrying the first working disc and / or the feet to be adjusted in height and / or laterally and / or tilted. The adjustment device can, in particular, comprise several such adjustment elements, which are movable translationally by means of an adjustment drive. By moving the adjustment elements translationally, the desired components can be adjusted in their position, for example, in their height, in a mechanically simple manner to adapt the alignment of the first working disc.

[0025] The specified orientation can, according to further configuration, be the orientation of the first working disc set within the configuration of the double- or single-sided machining center for operation. The first working disc is thus optimally aligned before a machining process, and this orientation is adopted as the target orientation. If the sensors on the feet detect a change from this target orientation, countermeasures can be taken as described above. As explained above, the sensors can record measured values ​​characterizing the orientation of the first working disc after each production process, and these measured values ​​can be compared with the measured values ​​after a previous production process and / or with measured values ​​associated with the specified orientation, in particular with values ​​measured in relation to the specified orientation.As explained, static monitoring of the alignment of the lower first working disc is carried out after each completion of a production process, in particular after the counter bearing element has been brought out of contact with the first working disc.

[0026] Exemplary embodiments of the invention are explained in more detail below with reference to the figures. They schematically show: Fig. 1 shows a double-sided machining machine according to the invention in a side view in a first operating state, Fig. 2 shows the double-sided machining machine made of Fig. 1 in a second operating state, Fig. 3 a top view of the double-sided machining machine according to Fig. 1 in the operating state of Figure 2 , Fig. 4 the representation from Fig. 3in another operating state, Fig. 5 a sectional view of an adjustment device of the double-sided machining machine according to a first embodiment, and Fig. 6 a sectional view of an adjustment device of the double-sided machining machine according to a further embodiment.

[0027] Unless otherwise stated, the same reference symbols in the figures denote the same objects.

[0028] The in the Figures 1 to 4The double-sided machining center shown here as an example has a machine base 10 that rests on a floor 14 of a production area via a plurality of feet 12. The machine base 10, designed, for example, as a housing, carries an annular, lower first support disk 16, which in turn carries an annular, lower first working disk 18. Furthermore, the machine base 10 carries a swivel arm 22 arranged on a pivot housing 20, which carries an annular, upper second support disk 24, which in turn carries an annular, upper second working disk 26. The upper second support disk 24, together with the upper second working disk 26, can be rotated about a drive shaft 28, for example, by means of a rotary drive arranged in the swivel arm 22.By means of a rotary drive (not shown in detail), the lower first support disk 16 and with it the lower first working disk 18 can also be rotatable, for example in the opposite direction to the upper second support disk 24 with the upper second working disk 26. An annular working gap is formed between the working disks 18, 26, wherein in . Figure 1 Figure 1 shows a state of the working discs 18, 26 moved apart in the axial direction, in which the working discs are not in contact with each other. Figure 2 The figure shows the working disks 18, 26 in their aligned position. By rotating the working disks 18, 26 in opposite directions, the workpieces, which are, for example, floatingly mounted in runner disks, can be machined in the annular working gap in a manner known per se, for example, by grinding, lapping or polishing.

[0029] As a comparison of Figures 1 and 2As can be seen, the swivel arm 22 can be used to adjust between the operating states of the Figures 1 and 2 The procedure will be carried out at a certain height. In the Figures 3 and 4 It can also be seen that the swivel arm 22, after the working discs 18, 26 have been brought out of contact, as in Figure 1 shown, together with the swivel housing 20, it can be swivelled to pivot the upper second carrier disk 24 and with it the upper second working disk 26 between a position opposite the lower first working disk 18 and a position away from it, in particular for loading runner disks with workpieces to be machined.

[0030] The feet 12 each include sensors 30, which can be, for example, weight sensors 30 that each measure a weight force acting on the feet 12. The measured values ​​of the sensors 30 are available at an evaluation unit 32 of the double-sided machining center. For example, in the Figure 1In the depicted state, the lower first working disc 18, together with the lower first support disc 16, can be optimally aligned horizontally. Once this alignment is complete, the sensors 30, controlled, for example, by the evaluation unit 32, can measure the weight force acting on the feet 12. These measured values ​​are stored as target values ​​for a predefined alignment of the lower first working disc 18, particularly by the evaluation unit 32. Subsequently, in the Figure 2 In the depicted state, workpiece machining takes place. After completion of this production process and re-disengagement of the working discs 18, 26, the sensors, controlled again, for example, by the evaluation unit 32, can once again measure the weight force acting on the feet 12. These measured values ​​can be compared by the evaluation unit 32 with the previously stored target measured values.

[0031] For example, if the weight distribution between the feet 12, measured by the sensors 30 after completion of a production process and the separation of the working discs 18, 26, changes compared to a weight distribution set at the beginning of this or a previous processing process for optimal alignment of the working disc 18, the evaluation unit 32 can issue a warning signal. Based on this, an operator can, for example, adjust the alignment of the first working disc 18 until the weight distribution measured by the sensors 30 corresponds to the specified value and thus the alignment returns to the specified orientation. Alternatively or additionally, the sensors 30 can also include optical sensors 30 that, for example, measure the height position of the feet 12, so that a deviation of the alignment from the specified orientation can be detected.

[0032] In the Figures 5 and 6 Adjustment devices are shown with which, for example, the alignment of the upper second working disc 26 can be adjusted by adjusting the height of the upper second support disc 24 and the upper second working disc 26. In the illustrated example, an adjustment element 34, in particular an adjustment wedge 34, is provided for this purpose, which is mounted in the upper second working disc 26 via an adjustment screw 36. Fig. 5 The example shown shows that the adjustment wedge 34 can be manually moved in or out of a conical adjustment holder 38 by translation. For example, by moving the adjustment wedge 34 translationally into the conical adjustment holder 38 by turning the screw 36, the second carrier disc 24 and with it the second working disc 26 are moved into the conical adjustment holder 38. Fig. 5moved downwards, thereby allowing the alignment of the second working disc 26 to be adjusted as desired. Similarly, the alignment of the lower first support disc 16 and the lower first working disc 18 can be adjusted using such an adjustment device.

[0033] Figure 6 Figure 1 shows a further embodiment in which the adjusting screw 36 and with it the adjusting wedge 34 can be adjusted translationally with respect to the adjusting receptacle 38 by means of an adjusting drive 40. In the figure shown in Fig. 5 In the example shown, an operator can, for instance, manually operate the adjusting screw 36 to adjust the alignment between the working discs 18, 26. In the example shown... Fig. 6In the illustrated example, the actuation of the adjusting screw 36 via the adjusting drive 40 can be carried out automatically, for example by the evaluation unit 32, if it detects an impermissible deviation of the alignment measured by the sensors 30, until the alignment corresponds again to the specified alignment. The alignment of the lower first support disc 16 and the lower first working disc 18 can then be adjusted accordingly. Reference sign

[0034] 10 Machine base 12 Feet 14 Base 16 First support disc 18 First working disc 20 Swivel housing 22 Swivel arm 24 Second support disc 26 Second working disc 28 Drive shaft 30 Sensors 32 Evaluation unit 34 Adjusting element 36 Adjusting screw 38 Adjustment mount 40 Adjustment drive

Claims

1. Double- or single-sided machining machine comprising a preferably annular, lower first working disk (18) and an upper counter bearing element (26), wherein the first working disk (18) and the counter bearing element (26) can be driven to rotate relative to each other via a rotary drive, wherein a working gap is formed between the first working disk (18) and the counter bearing element (26) for machining flat workpieces on both or one side, wherein the double- or single-sided machining machine further comprises a machine base (10) with feet (12) by which the machine base (10) rests on a floor (14) of a production room in the assembled state of the double- or single-sided machining machine, wherein the machine base (10) supports the first working disk (18) and the counter bearing element (26), characterized by the fact that the feet (12) have sensors (30) for monitoring the alignment of the first working disc (18).

2. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact that the counter bearing element (26) is formed by a preferably annular second working disk (26), wherein the working gap for machining flat workpieces on both or one side is formed between the first and second working disks (18, 26).

3. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact that the first working disc (18) is attached to a first support disc (16) which is also supported by the machine base part (10) and / or that the second working disc (26) is attached to a second support disc (24) which is also supported by the machine base part (10).

4. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact thatthe counter bearing element (26) is arranged on a swivel arm (22) located on the machine base part (10) and is pivotable with the swivel arm (22) relative to that of the first working disk (18).

5. Double- or single-sided machining machine according to claim 4, characterized by the fact that a rotary drive for the counter bearing element (26) arranged on the swivel arm (22) is integrated into the swivel arm (22).

6. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact that the sensors (30) include weight sensors (30) that measure a weight force acting on the feet (12).

7. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact that the sensors (30) comprise optical sensors (30) that optically measure a position of the feet (12), in particular a vertical position of the feet (12).

8. Double- or single-sided machining machine according to claim 7, characterized by the fact thatthe optical sensors (30) include laser sensors that measure the position of the feet (12), preferably via a time-of-flight measurement.

9. Double- or single-sided machining machine according to one of the preceding claims, characterized by the fact that an evaluation unit (32) is provided which receives the measurement data from the sensors (30).

10. Double- or single-sided machining machine according to claim 9, characterized by the fact that the evaluation unit (32) is designed to issue a warning signal when a deviation of the alignment of the first working disk (18) from a predetermined alignment is detected.

11. Double- or single-sided machining machine according to one of claims 9 or 10, characterized by the fact thatthe evaluation device (32) is designed to control the double- or single-sided machining machine in such a way that the orientation of the first working disc (18) corresponds again to the specified orientation when a deviation of the orientation of the first working disc (18) from a predetermined orientation is detected.

12. Double- or single-sided machining machine according to claim 11, characterized by the fact that the first working disc (18) and / or a first support disc (16) carrying the first working disc (18) and / or the feet (12) are provided with an adjustment device which can be controlled by the evaluation device (32) so that the alignment of the first working disc (18) corresponds again to the specified alignment.

13. Double- or single-sided machining machine according to claim 12, characterized by the fact thatThe adjusting device comprises at least one adjusting element (34) that can be moved translationally by means of an adjusting drive (40), by the translational movement of which the first working disk (18) and / or a first support disk (16) supporting the first working disk (18) and / or the feet (12) can be adjusted in height and / or laterally and / or tilted.

14. Double- or single-sided machining machine according to one of claims 10 to 13, characterized by the fact that The specified orientation is an orientation of the first working disk (18) set within the framework of a setup of the double- or single-sided machining machine for operation.

15. Double- or single-sided machining machine according to any of the preceding claims, characterized by the fact that The double or single-sided machining machine is a double or single-sided polishing machine, a double or single-sided lapping machine, or a double or single-sided grinding machine.

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