Grinding device

Abstract

To provide technique enabling suppression of such a problem that clogging occurs in a flow passage caused by polishing liquid remaining in the flow passage, and enabling detection of the occurrence of clogging if the clogging occurs in the flow passage.SOLUTION: A polishing apparatus 1 comprises a control device 90. The control device 90 performs: a washing processing in which, when the number of substrates Wf polished by a polishing machine 10 reaches a predetermined number, washing liquid is caused to flow through a flow passage 70a, and then a polishing liquid is caused to flow through the flow passage 70a; and a clogging detection process in which, when the washing liquid flows through the flow passage, the occurrence of clogging in the flow passage is detected based on pressure or flow volume of the washing liquid detected by a sensor 60, 61.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polishing apparatus.

Background Art

[0002] Conventionally, a polishing apparatus for polishing a substrate has been known (see, for example, Patent Document 1). Such a polishing apparatus includes a polishing machine for polishing a substrate and a flow path for supplying a polishing liquid to the polishing machine.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the conventional polishing apparatus as described above, when the number of substrates polished by the polishing machine increases, for example, the polishing liquid remaining in the flow path dries and becomes deposits, and partially adheres to the flow path, resulting in partial clogging of the flow path. The polished liquid is disturbed, which may reduce the polishing performance. Further, when a discharge nozzle having a discharge port narrower than the flow path is used downstream of the pipe, the polishing liquid tends to remain in the discharge port, so clogging is more likely to occur. Further, in the case of the conventional polishing apparatus as described above, the configuration is not such that the occurrence of clogging in this flow path (including the discharge nozzle) can be detected. In this case, there is a risk that the deposits grow and the flow path is completely blocked.

[0005] The present invention has been made in view of the above, and one of the objects is to provide a technique capable of suppressing the occurrence of clogging in the flow path due to the polishing liquid remaining in the flow path and detecting the occurrence of the clogging if it occurs in the flow path.

Means for Solving the Problems

[0006] (Aspect 1) To achieve the above objective, a polishing apparatus according to one aspect of the present invention comprises a polishing machine for polishing substrates, a flow path for supplying polishing liquid or cleaning liquid to the polishing machine, a switching device disposed in the flow path and switching between the polishing liquid and the cleaning liquid to circulate through the flow path, a sensor for detecting the pressure or flow rate of the cleaning liquid circulating through the flow path, and a control device. The control device performs a cleaning process in which, when the number of substrates polished by the polishing machine reaches a predetermined number, it controls the switching device to circulate the cleaning liquid through the flow path, and then controls the switching device to circulate the polishing liquid through the flow path, and a clogging detection process in which, when the cleaning liquid is circulating through the flow path, it detects that a blockage has occurred in the flow path based on the pressure or flow rate of the cleaning liquid detected by the sensor.

[0007] According to this embodiment, when the number of substrates polished by the polishing machine reaches a predetermined number, the flow path can be cleaned with a cleaning solution. This prevents clogging of the flow path caused by residual polishing solution. Furthermore, according to this embodiment, even if clogging occurs in the flow path, the occurrence of this clogging can be detected by a clogging detection process.

[0008] (Aspect 2) The above embodiment 1 is arranged downstream of the switching device in the flow path, The system further includes a flow rate adjustment device that adjusts the flow rate of the cleaning fluid circulating in the flow path to within a predetermined range, and the sensor may be a pressure sensor located downstream of the flow rate adjustment device in the flow path.

[0009] According to this embodiment, since the flow rate adjustment device described above is provided, when a blockage occurs in the flow path, the pressure at a point downstream of the flow rate adjustment device in the flow path can be effectively increased. As a result, a pressure sensor located downstream of the flow rate adjustment device can effectively detect this increase in pressure in the flow path. Consequently, it is possible to effectively detect when a blockage has occurred in the flow path.

[0010] (Aspect 3) In the above embodiment 2, the control device may detect that a blockage has occurred in the flow path based on the maximum, average, or minimum value of the pressure detected by the pressure sensor when the flow rate of the cleaning fluid is within the predetermined range.

[0011] (Aspect 4) In the above embodiment 2 or 3, the control device may determine that a blockage has occurred in the flow path when the pressure value detected by the pressure sensor is equal to or greater than a preset first threshold, the control device may determine that the degree of blockage in the flow path is small when the pressure value detected by the pressure sensor is equal to or greater than the first threshold and is less than a second threshold that is greater than the first threshold, and the control device may determine that the degree of blockage in the flow path is large when the pressure value detected by the pressure sensor is equal to or greater than the second threshold.

[0012] (Appendix 5) Any of the above embodiments 1 to 4 further comprises a notification device, and the control device may cause the notification device to notify the notification device that a blockage has occurred in the flow path when the blockage detection process detects that a blockage has occurred in the flow path.

[0013] (Aspect 6) In the above embodiment 4 or 5, the control device may prohibit the polishing of the substrate by the polishing machine if it determines that the degree of blockage in the flow path is large.

[0014] This configuration makes it possible to suppress the polishing of the substrate by the polishing machine even when the degree of blockage in the flow path is high.

[0015] (Aspect 7) In any one of the above Aspects 1 to 6, the flow path may include a single pipe, and the downstream end of the flow path may be constituted by the end of the pipe.

[0016] (Aspect 8) In any one of the above Aspects 1 to 6, the flow path may include a single pipe and a discharge nozzle having at least one discharge port connected to the downstream end of the pipe.

[0017] (Aspect 9) In any one of the above Aspects 1 to 9, each time the polishing machine polishes the substrate, the control device stores the number of substrates polished by the polishing machine, when the cleaning liquid is circulated through the flow path, the control device may reset the stored number of substrates to zero.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram showing the configuration of a polishing apparatus according to an embodiment. [Figure 2] FIG. 2(A) and FIG. 2(B) are schematic plan views of a polishing machine according to an embodiment. [Figure 3] FIG. 3(A) and FIG. 3(B) are schematic diagrams showing specific examples of a discharge nozzle that can be connected to the downstream end of a pipe according to an embodiment. [Figure 4] It is an example of a flowchart for explaining a cleaning process according to an embodiment. [Figure 5] It is an example of a flowchart for explaining a clogging detection process according to an embodiment. [Figure 6] FIG. 6(A) is a schematic diagram for explaining a pressure threshold value used in a clogging detection process according to an embodiment. FIG. 6(B) is a schematic diagram showing an example of a change in the flow rate of a cleaning liquid flowing through a flow path during the execution of a clogging detection process according to an embodiment. [Figure 7]It is a schematic diagram for explaining the configuration of the polishing apparatus according to Modification Example 1 of the embodiment. [Figure 8] It is a schematic diagram for explaining the threshold value used in the clogging detection process according to Modification Example 2 of the embodiment.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematically illustrated for easy understanding of the features, and the dimensional ratios of each component are not necessarily the same as the actual ones.

[0020] FIG. 1 is a schematic diagram showing the configuration of a polishing apparatus 1 according to the present embodiment. The polishing apparatus 1 includes a polishing machine 10, a polishing liquid supply device 20, a cleaning liquid supply device 30, a switching device 40, a flow rate adjusting device 50, various flow paths (flow path 70a, flow path 70c, flow path 70b), various sensors (pressure sensor 60, flow rate sensor 61), a notification device 80, and a control device 90.

[0021] First, the polishing machine 10 will be described. FIGS. 2(A) and 2(B) are schematic plan views of the polishing machine 10. Specifically, FIG. 2(A) schematically shows a state where the polishing machine 10 is polishing the substrate Wf, and FIG. 2(B) schematically shows a state where polishing by the polishing machine 10 is not being performed. In FIG. 2(A), the flow path 70a described later is located at the "first position", and in FIG. 2(B), the flow path 70a is located at the "second position".

[0022] Referring to FIGS. 1, 2(A), and 2(B), the polishing machine 10 is a device for polishing the substrate Wf. The polishing machine 10 according to the present embodiment is, as an example, a CMP polishing machine capable of performing Chemical Mechanical Polishing (CMP).

[0023] As illustrated in Figures 2(A) and 2(B), the polishing machine 10 according to this embodiment includes a polishing table 11 and a polishing head 12. The polishing machine 10 may further include a dresser 13 and an atomizer 14. The polishing table 11 holds a polishing pad Pd. Specifically, the polishing table 11 according to this embodiment is made up of a disc-shaped member, and the polishing pad Pd is attached to its upper surface. During polishing of the substrate Wf, the substrate Wf, as the material to be polished, is pressed against the upper surface (surface) of the polishing pad Pd. The upper surface of the polishing pad Pd corresponds to the polishing surface on which the substrate Wf is polished. The polishing table 11 is driven and rotated by a drive mechanism such as a rotary motor. The rotational movement of the polishing table 11 is controlled by a control device 90. The rotation direction of the polishing table 11 may be clockwise or counterclockwise in a plan view. In Figure 2(A), as an example, the polishing table 11 is rotating clockwise in a plan view.

[0024] The specific types of polishing pads Pd are not particularly limited, and include various types such as hard foam polishing pads, non-woven fabric polishing pads, and suede polishing pads. A cad can be used.

[0025] The polishing head 12 is a component for holding the substrate Wf. In Figure 2(A), the substrate Wf is held on the lower surface of the polishing head 12. The polishing head 12 is configured to rotate while pressing the lower surface of the substrate Wf (i.e., the surface to be polished) against the polishing pad Pd. Specifically, the polishing head 12 according to this embodiment is driven by a drive mechanism and rotates in a predetermined rotational direction (in Figure 2(A), for example, the same rotational direction as the polishing table 11).

[0026] Note that while the substrate Wf shown in Figure 2(A) is a circular substrate as an example, the shape of the substrate Wf is not limited to this. The substrate Wf may be rectangular or have other shapes.

[0027] During the polishing of the substrate Wf by the polishing machine 10, polishing fluid flows through the channel 70a. The polishing fluid discharged from this channel 70a is supplied to the polishing pad Pd. In the presence of this polishing fluid, the polishing machine 10 polishes the substrate Wf (CMP polishing) by rubbing it against the polishing pad Pd.

[0028] The dresser 13 is a device for dressing the polishing surface of the polishing pad Pd. Abrasive particles (such as diamonds) are arranged on the underside of the dresser 13. The atomizer 14 is a device for cleaning the polishing pad Pd by, for example, spraying pure water onto the polishing pad Pd at high pressure (a pressure above a predetermined pressure). Note that the polishing machine 10 can also be configured without the dresser 13 or atomizer 14.

[0029] In this embodiment, a predetermined region of the flow path 70a (at least the region a predetermined distance above the downstream end) is configured to rotate around the rotation axis 15. As a result, the flow path 70a can move between a "first position (or polishing position)" where the downstream end of the flow path 70a is located above the polishing pad Pd, as illustrated in Figure 2(A), and a "second position (or retracted position)" where the downstream end of the flow path 70a is not located above the polishing pad Pd, as illustrated in Figure 2(B). The rotational movement of the rotation axis 15 is controlled by the control device 90. Note that, at least when polishing the substrate Wf, the flow path 70a is in the first position.

[0030] Furthermore, the flow path 70a may be configured to oscillate within a predetermined range of oscillation angles around the rotation axis 15. In this case, the control device 90 may oscillate the flow path 70a, for example, when polishing the substrate Wf. In Figure 2(A), the range of oscillation angles is exemplified by "A1".

[0031] Referring to Figure 1, the polishing fluid supply device 20 is a device for supplying polishing fluid. The polishing fluid supply device 20 is in communication with the first inlet 41 of the switching device 40 via the flow path 70c. The specific configuration of the polishing fluid supply device 20 is not particularly limited, but the polishing fluid supply device 20 according to this embodiment, as an example, includes a tank for storing polishing fluid and a pump for pressurizing the polishing fluid from this tank. The operation of supplying polishing fluid by the polishing fluid supply device 20 is controlled by the control device 90.

[0032] As the polishing solution, a solution containing abrasives such as silica or cerium oxide can be used. The specific components of this polishing solution are not particularly limited and should be appropriately determined according to the type of substrate Wf.

[0033] The cleaning fluid supply device 30 is a device for supplying cleaning fluid. The cleaning fluid supply device 30 is connected to the second inlet 42 of the switching device 40 via the flow path 70b. The specific configuration is not particularly limited, but the cleaning fluid supply device 30 according to this embodiment includes, for example, a tank for storing cleaning fluid and a pump for pumping the cleaning fluid from the tank. The operation of supplying cleaning fluid by the cleaning fluid supply device 30 is controlled by the control device 90.

[0034] The cleaning solution can be any solution capable of cleaning the polishing solution remaining in the flow path 70a, and its specific components are not particularly limited. As a specific example of the cleaning solution, water, preferably pure water, can be used. Alternatively, a mixed fluid of water or pure water with a gas, or a mixed fluid of water or pure water with bubbles, may be used. Specifically, this gas or bubbles can be nitrogen, an inert gas, ozone, or other gases or bubbles. In this embodiment, pure water is used as an example of the cleaning solution. Specifically, pure water having an electrical resistivity of 0.1 (MΩ·cm) or higher can be used.

[0035] The switching device 40 is located in the flow path 70a. Specifically, the switching device 40 according to this embodiment is located at the upstream end of the flow path 70a. More specifically, the upstream end of the flow path 70a is connected to the outlet 43 of the switching device 40. The switching device 40 is configured to switch between the polishing fluid supplied from the polishing fluid supply device 20 and the cleaning fluid supplied from the cleaning fluid supply device 30 and allow them to flow through the flow path 70a. The operation of the switching device 40 is controlled by the control device 90. As such a switching device 40, for example, a flow path switching valve that can switch the inlet communicating with the outlet 43 between a first inlet 41 and a second inlet 42 can be used.

[0036] Specifically, the switching device 40 according to this embodiment switches between a "first state (or polishing fluid flowable state)" in which the first inlet 41 and outlet 43 are in communication and the second inlet 42 and outlet 43 are blocked, and a "second state (or cleaning fluid flowable state)" in which the second inlet 42 and outlet 43 are in communication and the first inlet 41 and outlet 43 are blocked. In the first state, the polishing fluid supplied from the polishing fluid supply device 20 can flow through the flow paths 70c and 70a. On the other hand, in the second state, the cleaning fluid supplied from the cleaning fluid supply device 30 can flow through the flow paths 70b and 70a.

[0037] The channel 70a is a channel (i.e., the "main channel") for supplying liquid (Lq) (specifically, polishing liquid or cleaning liquid) discharged from the switching device 40 to the polishing machine 10. In this embodiment, the channel 70a is configured to connect the outlet 43 of the switching device 40 to the polishing machine 10. When polishing the substrate Wf, polishing liquid flows through the channel 70a. On the other hand, when cleaning the channel 70a, cleaning liquid flows through the channel 70a.

[0038] In this embodiment, the flow path 70a is composed of a pipe 71 (note that the aforementioned flow paths 70b and 70c are also composed of pipes 71 similar to the pipe 71 of flow path 70a). Specifically, in this embodiment, the flow path 70a is composed of a single pipe 71 as an example. The specific value of the inner diameter of the pipe 71 (the diameter of the hollow portion through which the liquid flows in the pipe 71) is not particularly limited, but in this embodiment, as an example, it is 1 mm or more and 5 mm or less.

[0039] Furthermore, the downstream end of the flow path 70a according to this embodiment (i.e., the "liquid outlet in the flow path 70a") is formed by the end (downstream end) of this single pipe 71. As illustrated in Figure 1, the liquid Lq that has flowed through the pipe 71 is discharged from the end of the pipe 71. In Figure 1, as an example, the discharge of liquid Lq from the end of the pipe 71 in the axial direction of the pipe 71 is illustrated. In this embodiment, "downstream of the flow path 70a" specifically means "downstream in the flow direction of the liquid flowing through the flow path 70a."

[0040] Furthermore, the configuration of the flow path 70a is not limited to the configuration described above. Other examples are given. Furthermore, a discharge nozzle 72, as illustrated below, may be connected to the downstream end of the pipe 71, which serves as the flow path 70a.

[0041] Figures 3(A) and 3(B) are schematic diagrams showing specific examples of discharge nozzles 72 that can be connected to the downstream end of piping 71. As illustrated in Figure 3(A), a discharge nozzle 72 having a plurality of discharge ports 73 may be connected to the downstream end of piping 71. Each discharge port 73 is configured to discharge liquid Lq (polishing liquid or cleaning liquid) downwards. Furthermore, each discharge port 73 is configured to discharge the liquid Lq in a straight line (not in a fan shape). However, the configuration is not limited to this, and for example, each discharge port 73 may be configured to discharge the liquid Lq in a fan shape.

[0042] As illustrated in Figure 3(B), a discharge nozzle 72a having a single discharge port 73a may be connected to the downstream end of the piping 71. This discharge port 73a is configured to discharge liquid Lq downwards. Furthermore, as illustrated in Figure 3(B), this discharge port 73a is configured to discharge liquid Lq in a fan shape. However, the configuration is not limited to this, and for example, the discharge port 73a may be configured to discharge liquid Lq in a straight line.

[0043] Referring to Figure 1, the pressure sensor 60 is located in the flow path 70a. The pressure sensor 60 detects the pressure (kPa) of the liquid (polishing fluid or cleaning fluid) flowing through the flow path 70a and transmits this detected pressure to the control device 90. The specific location of the pressure sensor 60 in the flow path 70a is not particularly limited and may be located upstream or downstream of the flow rate adjustment device 50 in the flow path 70a. In this embodiment, as an example, the pressure sensor 60 is located downstream of the flow rate adjustment device 50 in the flow path 70a.

[0044] In Figure 1, the pressure sensor 60 is located downstream of the flow sensor 61, which will be described later, but the configuration is not limited to this. The pressure sensor 60 may be located upstream of the flow sensor 61 (however, in this embodiment, downstream of the flow rate adjustment device 50).

[0045] In this embodiment, the flow sensor 61 is positioned downstream of the flow rate adjustment device 50 in the flow path 70a. The flow sensor 61 detects the flow rate (ml / sec) of the liquid (polishing liquid or cleaning liquid) flowing through the flow path 70a and transmits this detected flow rate to the control device 90. The control device 90 controls the flow rate adjustment device 50 based on the flow rate detected by the flow sensor 61.

[0046] The flow sensor 61 may be integrated with the flow control device 50, which will be described later. In other words, the flow control device 50, which will be described later, may be a "flow control device with a flow sensor."

[0047] In this embodiment, the flow rate adjustment device 50 is located downstream of the switching device 40 in the flow path 70a. The flow rate adjustment device 50 is configured to adjust the flow rate of the cleaning liquid flowing through the flow path 70a to within a predetermined range, at least in the cleaning process described later. Specifically, the flow rate adjustment device 50 adjusts the flow rate of the cleaning liquid flowing through the flow path 70a based on the flow rate detected by the flow rate sensor 61.

[0048] More specifically, the flow rate adjustment device 50 according to this embodiment adjusts the flow rate of the cleaning liquid flowing through the flow path 70a in response to instructions from the control device 90 so that the flow rate of the cleaning liquid detected by the flow rate sensor 61 is within a predetermined range (within the range of lower limit F1 or higher and upper limit F2 or lower as shown in Figure 6(B) later).

[0049] Furthermore, the flow rate adjustment device 50 may also adjust the flow rate of the polishing liquid flowing through the flow path 70a during the polishing process of the substrate Wf to within a predetermined range. In this case, the predetermined range for the flow rate of the cleaning liquid and the predetermined range for the flow rate of the polishing liquid may be the same value or may be different values. However, it is preferable that the predetermined range for the flow rate of the cleaning liquid is greater than the predetermined range for the flow rate of the polishing liquid, in that the flow path 70a can be cleaned more effectively by the cleaning liquid compared to the case where it is not.

[0050] Therefore, in this embodiment, the predetermined range of the flow rate of the cleaning solution is greater than the predetermined range of the flow rate of the polishing solution. In other words, in this embodiment, the flow rate of the cleaning solution flowing through the channel 70a during the cleaning process described later is greater than the flow rate of the polishing solution flowing through the channel 70a during the polishing of the substrate Wf.

[0051] The notification device 80 is a device for notifying the user of the polishing device 1 of predetermined information. Specifically, the notification device 80 according to this embodiment is configured to notify the user that a blockage has occurred in at least the flow path 70a, upon receiving instructions from the control device 90. For example, a display can be used as the notification device 80.

[0052] The control device 90 is a device for comprehensively controlling the operation of the polishing apparatus 1. Specifically, the control device 90 according to this embodiment includes a microcomputer. This microcomputer includes a processor 91, a storage device 92 as a non-temporary storage medium, and the like. In the control device 90, the processor 91 controls the operation of the polishing apparatus 1 by operating based on the commands of the program stored in the storage device 92.

[0053] Next, the "cleaning process" performed by the control device 90 will be described. Figure 4 is an example of a flowchart illustrating the cleaning process according to this embodiment. The control device 90 repeatedly executes the flowchart in Figure 4 at predetermined intervals.

[0054] First, the control device 90 according to this embodiment stores the number of substrates Wf polished by the polishing machine 10 in the storage device 92 each time the polishing machine 10 polishes a substrate Wf. Furthermore, when the cleaning liquid is circulated through the flow path 70a (when step S20 described later is executed, or when the cleaning liquid is circulated through the flow path 70a by manual operation, etc.), the control device 90 according to this embodiment resets the number of substrates Wf stored in the storage device 92 (the number of substrates Wf polished by the polishing machine 10) to zero. As a result, the storage device 92 stores the number of substrates Wf polished by the polishing machine 10 between the last time the cleaning liquid circulated through the flow path 70a and the next time the cleaning liquid circulates through the flow path 70a.

[0055] In step S10, the control device 90 determines whether the number of substrates Wf polished by the polishing machine 10 (total number of substrates) has reached a predetermined number. Specifically, the control device 90 according to this embodiment determines whether the number of substrates stored in the storage device 92 (which is the cumulative number of substrates Wf polished by the polishing machine 10 since the last cleaning process was performed) has reached a predetermined number.

[0056] The specific number of these predetermined boards is not limited, but it is possible to use a number of boards that, when the number reaches this predetermined number, is considered likely to cause clogging in the flow path 70a. This predetermined number can be determined in advance through experiments or other means and stored in the memory device 92.

[0057] If the result in step S10 is Yes (when the number of substrates is the predetermined number), the control device 90 executes the cleaning process (step S20). Specifically, in this step S20 The control device 90 then stops the polishing of the substrate Wf by the polishing machine 10 and controls the cleaning fluid supply device 30 and the switching device 40 to circulate the cleaning fluid through the flow path 70a ("main cleaning process"). Next, the control device 90 controls the polishing fluid supply device 20 and the switching device 40 to circulate the polishing fluid through the flow path 70a ("replacement process").

[0058] More specifically, in this cleaning process, the control device 90 starts supplying cleaning fluid to the cleaning fluid supply device 30 and sets the switching device 40 to the aforementioned "second state". As a result, the cleaning fluid supplied from the cleaning fluid supply device 30 flows through the flow path 70b and then through the flow path 70a. This allows the flow path 70a to be cleaned with the cleaning fluid. Specifically, any polishing fluid remaining in the flow path 70a can be washed away with the cleaning fluid, and any deposits accumulated in the flow path 70a can also be washed away with the cleaning fluid.

[0059] Meanwhile, during the replacement process, the control device 90 starts supplying polishing fluid to the polishing fluid supply device 20 and sets the switching device 40 to the aforementioned "first state". As a result, the polishing fluid supplied from the polishing fluid supply device 20 flows through the flow path 70c and then through the flow path 70a. This allows the cleaning fluid remaining in the flow path 70a to be replaced with the polishing fluid.

[0060] In this cleaning process, the control device 90 may control the cleaning liquid supply device 30 and the flow rate adjustment device 50 to circulate the cleaning liquid through the flow path 70a at a predetermined flow rate (ml / sec) and for a predetermined cleaning time (sec).

[0061] The predetermined flow rate of the cleaning solution can be any flow rate that falls within the predetermined range described above (above the lower limit F1 and below the upper limit F2), that is, any flow rate selected from within this predetermined range. Specifically, as an example of this predetermined flow rate, for example, the average value of the lower limit F1 and the upper limit F2 may be used.

[0062] Furthermore, in this case, it is preferable that the "pre-set cleaning time" mentioned above is set to a time that is greater than or equal to a predetermined "minimum cleaning time". As this minimum cleaning time, for example, the value obtained by dividing the volume (ml) from the switching device 40 to the downstream end in the flow path 70a by the predetermined flow rate (ml / sec) mentioned above can be used.

[0063] Furthermore, the control device 90 may execute step S20 with the flow path 70a positioned in the aforementioned "first position (see Figure 2(A))". This configuration is preferable because it eliminates the need to return the flow path 70a to the first position when polishing the next substrate Wf (at the start of step S30, which will be described later).

[0064] Alternatively, the control device 90 may execute step S20 with the flow path 70a positioned in the aforementioned "second position (see Figure 2(B))". This configuration is preferable because it can suppress the residue of the cleaning fluid discharged from the flow path 70a on the polishing pad Pd of the polishing table 11. When step S20 is executed with the flow path 70a in the "second position" in this manner, it is preferable for the control device 90 to return the flow path 70a to the "first position" between the end of step S20 and the start of step S30, which will be described later.

[0065] Referring to Figure 4, after step S20, the control device 90 causes the polishing machine 10 to polish the next substrate Wf (step S30). That is, in step S30, the polishing of the substrate Wf by the polishing machine 10 is resumed. Specifically, in this case, as described above, the polishing machine 10 polishes the substrate Wf by rubbing it against the polishing pad Pd in ​​the presence of polishing fluid supplied from the polishing fluid supply device 20. If No is determined in step S10, the control device 90 executes step S30 without executing step S20.

[0066] As described above, according to this embodiment, when the number of substrates Wf polished by the polishing machine 10 reaches a predetermined number, the cleaning process related to step S20 is executed, so that the flow path (specifically, the flow path 70a in this embodiment) can be cleaned with the cleaning solution. This makes it possible to suppress the occurrence of clogging in the flow path 70a due to polishing solution remaining in the flow path 70a.

[0067] Specifically, according to this embodiment, it is possible to prevent the polishing liquid remaining in the pipe 71 of the flow path 70a from drying and sticking to the inner wall surface of the pipe 71, or from sticking to the downstream end (outlet) of the pipe 71. Furthermore, if discharge nozzles 72 and 72a are connected to the pipe 71, it is also possible to prevent the polishing liquid from sticking to the discharge nozzles 72 and 72a, and causing blockages in the discharge nozzles 72 and 72a.

[0068] Furthermore, according to this embodiment, in the cleaning process related to step S20, after cleaning the channel 70a with the cleaning solution, the cleaning solution remaining in the channel 70a is replaced with the polishing solution. This prevents the polishing solution supplied to the polishing machine 10 in step S30 from being diluted by the cleaning solution remaining in the channel 70a. As a result, it is possible to prevent a decrease in the polishing speed of the substrate Wf due to the polishing solution being diluted by the cleaning solution.

[0069] In this embodiment, "the flow path 70a becomes clogged" includes not only the phenomenon where the flow path 70a is completely blocked and liquid cannot flow through it, but also the phenomenon where, for example, deposits of polishing liquid adhere to a part of the inner wall of the flow path 70a, making it difficult for liquid to flow through it. Furthermore, if a discharge nozzle 72 as illustrated in Figure 3(A) is connected to the downstream end of the piping 71, "the flow path 70a becomes clogged" also includes the phenomenon where clogs occur in at least one of the multiple discharge ports 73 of this discharge nozzle 72.

[0070] Next, the "clogging detection process" performed by the control device 90 will be described. Figure 5 is an example of a flowchart for explaining the clogging detection process according to this embodiment. In this embodiment, the control device 90 starts executing step S40 while the cleaning process related to step S20 described above is being executed. In step S40, the control device 90 detects that a clogging has occurred in the flow path 70a based on the pressure detected by the pressure sensor 60 when the cleaning liquid is flowing through the flow path 70a during the cleaning process (i.e., the pressure of the cleaning liquid in the flow path 70a). The details of this will be explained using the figures below.

[0071] Figure 6(A) is a schematic diagram illustrating the pressure thresholds used in the blockage detection process. Specifically, Figure 6(A) illustrates a first threshold P1 and a second threshold P2 as pressure thresholds used to determine whether or not a blockage has occurred in the flow path 70a. The second threshold P2 is a larger value than the first threshold P1. The first threshold P1 and the second threshold P2 are pre-stored in the storage device 92 of the control device 90. Furthermore, lines L1, L2, and L3 illustrated in Figure 6(A) schematically show the time change of the cleaning fluid pressure detected by the pressure sensor 60.

[0072] In step S40, the control device 90 acquires the pressure value of the cleaning fluid detected by the pressure sensor 60 and determines whether the acquired pressure value is equal to or greater than a preset first threshold P1. If the pressure value detected by the pressure sensor 60 is equal to or greater than the first threshold P1, the control device 90 determines that a blockage has occurred in the flow path 70a (i.e., it detects that a blockage has occurred in the flow path 70a).

[0073] On the other hand, if the pressure value detected by the pressure sensor 60 is less than the first threshold P1, the control device 90 determines that there is no blockage in the flow path 70a (i.e., the flow path 70a is "normal"). ) is determined to be the case.

[0074] Furthermore, the control device 90 determines that the degree of blockage in the flow path 70a is small (or determines that a "minor malfunction" has occurred in the flow path 70a) if the pressure value detected by the pressure sensor 60 is equal to or greater than the first threshold P1 and less than the second threshold P2. The control device 90 determines that the degree of blockage in the flow path 70a is large (or determines that a "major malfunction" has occurred in the flow path 70a) if the pressure value detected by the pressure sensor 60 is equal to or greater than the second threshold P2.

[0075] In other words, in Figure 6(A), if the line indicating the pressure detected by the pressure sensor 60 is line L1, the control device 90 determines that there is no blockage in the flow path 70a; if it is line L2, it determines that the degree of blockage in the flow path 70a is small; and if it is line L3, it determines that the degree of blockage in the flow path 70a is large.

[0076] The specific value of the first threshold P1 is not particularly limited, but in this embodiment, a flow path 70a in a state where no blockage has occurred (a normal flow path 70a) is prepared in advance, the pressure of the cleaning fluid flowing through a predetermined point in this normal flow path 70a is measured in advance, and the value obtained by adding a predetermined pressure to this measured pressure value (i.e., the normal pressure value) is used. It is preferable to use a value that is larger than the measurement accuracy value (i.e., the measurement error of the pressure sensor 60) guaranteed by the manufacturer of the pressure sensor 60 as this predetermined pressure.

[0077] The specific value of the second threshold P2 is not particularly limited, as long as it is greater than the first threshold P1; it can be set appropriately, for example, through experiments.

[0078] In this embodiment, the control device 90 compares the pressure value of the cleaning fluid detected by the pressure sensor 60 with two thresholds (first threshold P1 and second threshold P2) in the blockage detection process, as described above, but is not limited to this configuration. The control device 90 may also determine whether or not a blockage has occurred in the flow path 70a by comparing the pressure value of the cleaning fluid detected by the pressure sensor 60 with one threshold (only the first threshold P1 or only the second threshold P2) in the blockage detection process.

[0079] Figure 6(B) is a schematic diagram showing an example of the change in the flow rate of the cleaning fluid flowing through the channel 70a during the execution of the blockage detection process. Specifically, line L4 shown in Figure 6(B) illustrates an example of the change in the flow rate of the cleaning fluid flowing through this channel 70a.

[0080] In step S40, the control device 90 may cause the pressure sensor 60 to detect the pressure of the cleaning fluid if the flow rate of the cleaning fluid flowing through the flow path 70a is within a predetermined range. Specifically, this predetermined range is the range between a lower limit F1 and an upper limit F2 as illustrated in Figure 6(B), and this is also the target range for controlling the flow rate of the flow rate adjustment device 50.

[0081] Specifically, in this case, the pressure sensor 60 monitors the pressure when the flow rate of the cleaning fluid circulating through the flow path 70a (which is acquired by the flow sensor 61) is within the range of a lower limit F1 or higher and an upper limit F2 or lower, and transmits this monitored pressure to the control device 90. The control device 90 may then detect that a blockage has occurred in the flow path 70a by comparing the maximum, average, or minimum pressure detected by the pressure sensor 60 when the flow rate of the cleaning fluid is within a predetermined range with the aforementioned thresholds (first threshold P1, second threshold P2).

[0082] Referring to Figure 5, after step S40, the control device 90 executes step S41. In step S41, the control device 90 causes the notification device 80 to notify whether or not a blockage has occurred in the flow path 70a. Specifically, the control device 90 according to this embodiment causes the notification device 8 As an example, the display shows that a blockage has occurred in the flow path 70a. With this configuration, the user can quickly recognize that a blockage has occurred in the flow path 70a.

[0083] Furthermore, it is preferable that the control device 90 also notifies the notification device 80 of the degree of blockage in the flow path 70a (or that a minor malfunction has occurred in the flow path 70a) or the degree of blockage in the flow path 70a (or that a major malfunction has occurred in the flow path 70a). With this configuration, the user can grasp the degree of blockage in the flow path 70a at an early stage.

[0084] Furthermore, if the control device 90 determines in step S40 that the degree of clogging of the flow path 70a is significant, it may prohibit the polishing of the substrate Wf by the polishing machine 10. In other words, in this case, the polishing of the substrate Wf by the polishing machine 10 will not be performed. With this configuration, it is possible to suppress the polishing of the substrate Wf by the polishing machine 10 even when the degree of clogging of the flow path 70a is significant.

[0085] In this case, the control device 90 only needs to release the prohibition on polishing when it receives a "prohibition release command" indicating that the prohibition on polishing the substrate Wf by the polishing machine 10 should be lifted. Specifically, in this case, for example, the control device 90 may receive the prohibition release command when the user presses a "prohibition release button" installed on the polishing device 1.

[0086] As described above, according to this embodiment, a cleaning process is performed, so when the number of substrates Wf polished by the polishing machine 10 reaches a predetermined number, the flow path 70a can be cleaned with cleaning solution. This prevents clogging of the flow path (specifically flow path 70a) due to polishing solution remaining in the flow path 70a. Furthermore, even if clogging occurs in the flow path 70a, the clogging detection process can detect the occurrence of clogging in the flow path 70a.

[0087] Furthermore, according to this embodiment, since a flow rate adjustment device 50 is provided, if a blockage occurs in the flow path 70a, the pressure at the point downstream of the flow rate adjustment device 50 in the flow path 70a can be effectively increased. As a result, the pressure sensor 60 located downstream of the flow rate adjustment device 50 can effectively detect this increase in pressure in the flow path 70a. Consequently, it is possible to effectively detect that a blockage has occurred in the flow path 70a.

[0088] In the embodiment described above, the control device 90 may, in step S10, not only actually measure the number of substrates Wf polished by the polishing machine 10 and determine whether the number of substrates Wf polished by the polishing machine 10 has reached a predetermined number, but may also determine whether the number of substrates Wf polished by the polishing machine 10 has reached a predetermined number based on other parameters that have a correlation with the number of substrates Wf polished by the polishing machine 10.

[0089] For example, this parameter could be the operating time of the polishing machine 10 (i.e., the total time spent polishing the substrates Wf), the supply time of the polishing liquid by the polishing liquid supply device 20, or the amount of polishing liquid supplied by the polishing liquid supply device 20. Alternatively, if a flow path on / off valve for switching the supply and stop of the polishing liquid is located in the flow path 70a, the number of times this flow path on / off valve is opened and closed can also be used as this parameter. Note that the longer the operating time of the polishing machine 10, the longer the supply time of the polishing liquid, the greater the amount of polishing liquid supplied, or the more times the flow path on / off valve is opened and closed, the greater the number of substrates Wf polished by the polishing machine 10.

[0090] (Modification of Embodiment 1) In the embodiment described above, the placement of the flow rate adjustment device 50, the flow rate sensor 61, and the pressure sensor 60 is not limited to the flow path 70a. Figure 7 is a schematic diagram illustrating the configuration of the polishing apparatus 1a according to modified example 1 of the embodiment. Note that the polishing machine 10, the notification device 80, and the control device 90 are not shown in Figure 7.

[0091] The polishing apparatus 1a according to this modified example differs from the polishing apparatus 1 illustrated in Figure 1 in that the flow rate adjustment device 50, flow rate sensor 61, and pressure sensor 60 are not arranged in the flow path 70a, the flow rate adjustment device 50 and flow rate sensor 61 are arranged in the flow paths 70b and 70c respectively, and the pressure sensor 60 is arranged in the flow path 70b. The other configurations of the polishing apparatus 1a according to this modified example are the same as those of the polishing apparatus 1.

[0092] The flow rate adjustment device 50 located in the flow path 70b adjusts the flow rate of the cleaning liquid circulating in the flow path 70b to within a predetermined range based on the flow rate of the cleaning liquid detected by the flow rate sensor 61 located in the flow path 70b. The method of adjusting the flow rate of the cleaning liquid by this flow rate adjustment device 50 is the same as that of the flow rate adjustment device 50 (flow rate adjustment device 50 located in the flow path 70a) according to the embodiment described above.

[0093] On the other hand, the flow rate adjustment device 50 located in the flow path 70c adjusts the flow rate of the polishing liquid circulating in the flow path 70c to within a predetermined range based on the flow rate of the polishing liquid detected by the flow rate sensor 61 located in the flow path 70c. Note that if the flow rate of the polishing liquid is not to be adjusted, the polishing device 1a may be configured without the flow rate adjustment device 50 and flow rate sensor 61 for the polishing liquid.

[0094] The control device 90 according to this modified example also executes the flowcharts shown in Figures 4 and 5 described above.

[0095] If a blockage occurs in the flow path 70a, the pressure of the cleaning fluid flowing through the flow path 70a increases, and as a result, the pressure of the cleaning fluid flowing through the flow path 70b, which is connected to the flow path 70a via the switching device 40, also increases. Therefore, in this modified example as well, a blockage in the flow path 70a can be detected in the same manner as in the embodiment described above, based on the pressure detected by the pressure sensor 60 located in the flow path 70b.

[0096] Furthermore, according to this modified configuration, since the flow rate adjustment device 50, flow rate sensor 61, and pressure sensor 60 are not located in the flow path 70a, the switching device 40 can be positioned closer to the downstream end of the flow path 70a compared to the case where these components are located in the flow path 70a. In this case, the amount of polishing fluid in the flow path 70a that will be discarded during the cleaning process can be reduced.

[0097] (Modified embodiment 2) Next, a polishing apparatus 1 according to a modified example 2 of the embodiment will be described. The polishing apparatus 1 according to this modified example differs from the polishing apparatus 1 according to the embodiment described above mainly in that, in detecting a blockage in the flow path 70a, it uses the detection value of the flow sensor 61 instead of the detection value of the pressure sensor 60. In this case, referring to Figure 1, the polishing apparatus 1 according to this modified example can also be configured without a pressure sensor 60.

[0098] The control device 90 according to this modified example executes the flowcharts shown in Figures 4 and 5, but the execution content of step S40 in the flowchart of Figure 5 differs from that of the previously described embodiment.

[0099] Specifically, in step S40, the control device 90 according to this modified example detects that a blockage has occurred in the flow path 70a based on the flow rate detected by the flow sensor 61 when the cleaning liquid is flowing through the flow path 70a (i.e., the flow rate of the cleaning liquid in the flow path 70a).

[0100] Specifically, in step S40, the control device 90 according to this modified example acquires the flow rate detected by the flow sensor 61 (i.e., the flow rate of the cleaning fluid flowing through the flow path 70a). Next, the control device 90 calculates the difference (referred to as the "flow rate difference") between a preset reference flow rate and the flow rate detected by the flow sensor 61.

[0101] As the above-mentioned standard flow rate, for example, the flow rate of the cleaning solution when there is no blockage in the flow path 70a can be used. Specifically, the control target value of the cleaning solution flow rate by the flow rate adjustment device 50 (the "predetermined flow rate" mentioned above) can be used as this standard flow rate. More specifically, the average value of the upper limit value F2 and the lower limit value F1 mentioned above in Figure 6(B) can be used as this standard flow rate. An appropriate value for this standard flow rate is determined in advance through experiments, etc., and stored in the memory device 92.

[0102] The greater the degree of blockage in the flow path 70a, the lower the flow rate of the cleaning fluid circulating through the flow path 70a. Therefore, the "flow rate difference" mentioned above takes on a larger value as the degree of blockage in the flow path 70a increases. Accordingly, the control device 90 according to this modified example determines the degree of blockage in the flow path 70a based on this flow rate difference, as will be explained below.

[0103] Figure 8 is a schematic diagram illustrating the thresholds used in the blockage detection process according to this modified example. Specifically, Figure 8 illustrates a third threshold P3 and a fourth threshold P4 as thresholds for the "flow rate difference" used to determine whether or not a blockage has occurred in the flow path 70a. The fourth threshold P4 is a larger value than the third threshold P3. In addition, lines L5, L6, and L7 illustrated in Figure 8 schematically show the change in flow rate difference over time.

[0104] In step S40, the control device 90 according to this modified example determines that a blockage has occurred in the flow path 70a if the difference between the reference flow rate and the flow rate detected by the flow sensor 61 ("flow rate difference") is equal to or greater than a preset third threshold P3. The control device 90 determines that the degree of blockage in the flow path 70a is small if the flow rate difference is equal to or greater than the third threshold P3 and less than the fourth threshold P4. The control device 90 determines that the degree of blockage in the flow path 70a is large if the flow rate difference is equal to or greater than the fourth threshold P4.

[0105] In other words, in Figure 8, in the case of line L5, the control device 90 determines that there is no blockage in the flow path 70a; in the case of line L6, it determines that the degree of blockage in the flow path 70a is small; and in the case of line L7, it determines that the degree of blockage in the flow path 70a is large.

[0106] In this modified example, it is preferable that the control device 90 notifies the notification device 80 of the determined degree of blockage in the flow path 70a.

[0107] This modified example can also achieve the same effects and advantages as the embodiment described above.

[0108] Furthermore, in the embodiments described above, as well as in the first and second modifications of the embodiments, the control device 90 may also cause the notification device 80 to notify the notification device 80 when the pressure of the polishing fluid flowing through the channel 70a exceeds a predetermined threshold, or when the flow rate of the polishing fluid flowing through the channel 70a falls below a predetermined threshold. With this configuration, the user can quickly recognize when it is desirable to perform cleaning of the channel 70a.

[0109] Although embodiments and variations of the present invention have been described in detail above, the present invention is not limited to these specific embodiments and variations, and various modifications and changes are possible within the scope of the present invention as described in the claims. [Explanation of Symbols]

[0110] 1 Polishing equipment 10 Polishing machine 40 Switching device 50 Flow rate adjustment device 60. Pressure sensor ("sensor") 61 Flow sensor ("sensor") 70a, 70b, 70c flow path 71 Piping 72 Discharge nozzles 73,73a Discharge port 90 Control device Wf substrate

Claims

1. A polishing machine for polishing circuit boards, A channel for supplying polishing liquid or cleaning liquid to the polishing machine, A switching device is positioned in the aforementioned flow path and switches between the polishing liquid and the cleaning liquid, and circulates them in the aforementioned flow path. A sensor for detecting the pressure or flow rate of the cleaning liquid flowing through the aforementioned channel, A control device is provided, The control device is When the number of substrates polished by the polishing machine reaches a predetermined number, the switching device is controlled to allow the cleaning solution to flow through the flow path, and then the switching device is controlled to allow the polishing solution to flow through the flow path, a cleaning process, A polishing apparatus that performs a blockage detection process, which detects when a blockage has occurred in the flow path based on the pressure or flow rate of the cleaning liquid detected by the sensor, while the cleaning liquid is flowing through the flow path.

2. The flow path is further provided with a flow rate adjustment device located downstream of the switching device, which adjusts the flow rate of the cleaning liquid circulating in the flow path to within a predetermined range. The polishing apparatus according to claim 1, wherein the sensor is a pressure sensor located downstream of the flow rate adjustment device in the flow path.

3. The polishing apparatus according to claim 2, wherein the control device detects that a blockage has occurred in the flow path based on the maximum, average, or minimum value of the pressure detected by the pressure sensor when the flow rate of the cleaning liquid is within the predetermined range.

4. The control device determines that a blockage has occurred in the flow path when the pressure value detected by the pressure sensor is equal to or greater than a preset first threshold. The polishing apparatus according to claim 2, wherein the control device determines that the degree of clogging of the flow path is small when the pressure value detected by the pressure sensor is greater than or equal to the first threshold and less than the second threshold which is greater than the first threshold, and determines that the degree of clogging of the flow path is large when the pressure value detected by the pressure sensor is greater than or equal to the second threshold.

5. It is further equipped with a notification device, The polishing apparatus according to claim 1, wherein the control device causes the notification device to notify the notification device that a blockage has occurred in the flow path when the blockage detection process detects that a blockage has occurred in the flow path.

6. The polishing apparatus according to claim 4, wherein the control device prohibits polishing the substrate by the polishing machine when it determines that the degree of blockage in the flow path is large.

7. The aforementioned flow path comprises a single pipe, The polishing apparatus according to claim 1, wherein the downstream end of the flow path is formed by the end of the piping.

8. The polishing apparatus according to claim 1, wherein the flow path comprises a single pipe and a discharge nozzle having at least one discharge port connected to the downstream end of the pipe.

9. The control device stores the number of substrates polished by the polishing machine each time the polishing machine polishes a substrate. When the cleaning liquid is circulated through the flow path, the control device will check the stored information of the substrate The polishing apparatus according to claim 1, which resets the number of sheets to zero.

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