JP6112899B2 - Abrasive liquid supply apparatus and substrate processing apparatus - Google Patents

Description

  The present invention relates to an abrasive liquid supply apparatus and a substrate processing apparatus.

  In recent years, a substrate processing apparatus has been used to polish the surface of a substrate such as a semiconductor wafer. The substrate processing apparatus includes a polishing table to which a polishing pad for polishing a substrate is attached, a rotation driving unit that rotates the polishing table, and a polishing liquid supply device that supplies a polishing polishing liquid (slurry) onto the polishing pad. And a top ring that holds the substrate and presses it onto the polishing pad. The substrate processing apparatus supplies the polishing abrasive liquid onto the polishing pad by the abrasive liquid supply apparatus, and polishes the surface of the substrate by pressing the substrate held by the top ring against the polishing pad while rotating the polishing table.

  The abrasive liquid supply device includes an abrasive liquid pipe for supplying the polishing abrasive liquid, and a pump that pressurizes and supplies the polishing abrasive liquid onto the polishing pad. The abrasive liquid supply device pressurizes the polishing abrasive liquid with a pump and supplies it onto the polishing pad via the abrasive liquid piping. Here, in the substrate polishing process, it is necessary to supply an appropriate amount of polishing abrasive liquid onto the polishing pad. For this reason, in the abrasive liquid supply device, a flow meter is provided in the abrasive liquid pipe, the flow rate in the abrasive liquid pipe is monitored, and a constant flow valve provided in the abrasive liquid pipe is installed on the basis of the monitored polishing abrasive liquid flow rate. To be controlled.

JP 2000-202774 A

  However, the prior art does not consider that the accuracy of flow rate detection is reduced due to bubbles generated in the polishing abrasive liquid.

  That is, the polishing abrasive liquid has a high pressure in the vicinity of being discharged from the pump, but the pressure decreases as it goes downstream of the abrasive liquid piping, and bubbles may be generated in the polishing abrasive liquid due to the pressure drop. . When bubbles are generated in the polishing abrasive liquid and stay in the abrasive pipe, the flow rate of the polishing abrasive liquid may not be measured.

  For example, when an ultrasonic flow meter is given as an example of the flow meter, the ultrasonic flow meter is configured to have an ultrasonic arrival time from the upstream side to the downstream side of the flow of the polishing abrasive liquid and an ultrasonic wave from the downstream side to the upstream side. The flow rate is measured based on the difference from the arrival time. However, if bubbles remain in the abrasive liquid piping, the ultrasonic waves are reflected by the bubbles, and as a result, the ultrasonic waves hardly reach the receiving side, and the flow rate may not be measured. In this case, the abrasive liquid supply device may interrupt the polishing process by issuing an alarm regardless of whether or not the actual flow rate of the polishing abrasive liquid is normal.

  Accordingly, an object of the present invention is to suppress a decrease in the accuracy of flow rate detection due to bubbles generated in the polishing abrasive liquid.

An abrasive liquid supply device of the present invention has been made in view of the above problems, and an abrasive liquid pipe for supplying an abrasive liquid to a polishing table having a polishing surface for polishing a substrate, and the abrasive liquid pipe A pump for supplying the polishing abrasive liquid to the polishing table, a flow meter for measuring the flow rate of the polishing abrasive liquid flowing through the abrasive liquid piping, and a measurement for measuring the flow rate of the polishing abrasive liquid by the flow meter. A controller for controlling the pressure of the polishing abrasive liquid in the abrasive liquid piping so that the abrasive polishing liquid and bubbles are not mixed on a surface orthogonal to the flow direction of the polishing abrasive liquid in the region. Features.

  Further, in the measurement area, the control unit is configured so that the pressure of the polishing abrasive liquid is a pressure at which the polishing abrasive liquid and bubbles do not coexist on a surface orthogonal to the flow direction of the polishing abrasive liquid. The number of rotations can be controlled.

  Further, in the case where the control unit further includes a variable orifice capable of adjusting the opening degree of the abrasive fluid pipe on the downstream side of the flow meter of the abrasive fluid pipe, the controller is configured such that the pressure of the abrasive abrasive fluid in the measurement region is The opening degree of the variable orifice can be controlled so that the polishing abrasive liquid and bubbles do not coexist on the surface orthogonal to the flow direction of the polishing abrasive liquid.

  Moreover, the orifice which narrows the opening degree of this abrasive fluid piping in the downstream from the said flow meter of the said abrasive fluid piping can be further provided.

  The abrasive liquid pipe is connected to a first abrasive liquid pipe having a first diameter and provided with the flowmeter, and a downstream side of the first abrasive liquid pipe, and is smaller in diameter than the first diameter. And a second abrasive liquid pipe having a second diameter.

  In the case where the control unit further includes a pressure detector that detects a pressure upstream of the flow meter of the abrasive liquid piping, the control unit detects that the pressure detected by the pressure detector is the polishing abrasive liquid in the measurement region. The rotational speed of the pump or the opening of the variable orifice can be controlled so that the pressure is such that the polishing abrasive liquid and bubbles do not coexist on the surface orthogonal to the flow direction.

  Further, the control unit controls the pressure of the polishing abrasive liquid in the abrasive liquid pipe so that bubbles do not occur in the polishing abrasive liquid in a measurement region in which the flow rate of the polishing abrasive liquid is measured by the flow meter. can do.

  In the case where the control unit further includes a bubble detector that detects whether or not bubbles are generated in the abrasive fluid pipe on the upstream side of the flowmeter of the abrasive fluid pipe, If it is determined that the pump is rotating, the rotational speed of the pump is increased, or the opening of the variable orifice that can adjust the opening of the abrasive fluid pipe is adjusted downstream of the flow meter of the abrasive fluid pipe. By controlling the degree small, the pressure of the polishing abrasive liquid can be increased.

  Further, in the case where the abrasive pipe is further provided with a circulation pipe for branching from the upstream side of the flow meter to circulate the polishing abrasive liquid to the suction side of the pump, the circulation pipe is provided with an opening of the circulation pipe. An orifice that narrows the degree can be provided.

  In addition, when the polishing pipe further includes a circulation pipe for branching from the upstream side of the flow meter to circulate the polishing abrasive liquid to the suction side of the pump, the circulation pipe has a first diameter. A first circulation pipe, and a second circulation pipe connected to the downstream side of the first circulation pipe and having a second diameter smaller than the first diameter.

  Further, the substrate processing apparatus of the present invention provides any of the above abrasive liquid supply apparatuses, a polishing table having a polishing surface for polishing the substrate, and the polishing liquid supplied to the polishing table by the abrasive liquid supply apparatus. And a substrate holding part that polishes the substrate by holding the substrate and pressing the substrate against the polishing surface.

  According to this invention of this application, it can suppress that the precision of a flow rate detection falls resulting from the bubble which generate | occur | produced in polishing abrasive liquid.

FIG. 1 is a perspective view schematically showing the overall configuration of the substrate processing apparatus. FIG. 2 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the first embodiment. FIG. 3 is a diagram for explaining uniform bubbles and non-uniform bubbles. FIG. 4 is a diagram illustrating an example in which bubbles stay in the flow rate measurement region. FIG. 5 is a diagram illustrating a processing flow of the substrate processing apparatus according to the first embodiment. FIG. 6 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the second embodiment. FIG. 7 is a diagram illustrating a processing flow of the substrate processing apparatus according to the second embodiment. FIG. 8 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the third embodiment. FIG. 9 is a diagram illustrating a processing flow of the substrate processing apparatus according to the third embodiment.

  Hereinafter, a polishing liquid supply apparatus and a substrate processing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, a CMP (Chemical Mechanical Polishing) polishing apparatus will be described as an example, but the present invention is not limited thereto.

  FIG. 1 is a perspective view schematically showing the overall configuration of the substrate processing apparatus. As shown in FIG. 1, a substrate processing apparatus 100 includes a polishing table 110 on which a polishing pad 108 for polishing a substrate 102 such as a semiconductor wafer can be mounted on an upper surface, and a first electric motor that rotationally drives the polishing table 110. 112, a top ring (substrate holding unit) 116 that can hold the substrate 102, and a second electric motor 118 that rotationally drives the top ring 116.

  In addition, the substrate processing apparatus 100 includes a dresser unit 124 that includes a polishing liquid supply apparatus 200 that can supply a polishing abrasive liquid containing a polishing material on the upper surface of the polishing pad 108 and a dresser disk 122 that conditions the polishing pad 108. And comprising.

  When polishing the substrate 102, a polishing abrasive liquid containing an abrasive is supplied from the abrasive liquid supply apparatus 200 to the upper surface of the polishing pad 108, and the polishing table 110 is rotationally driven by the first electric motor 112. Then, the substrate 102 held by the top ring 116 is pressed against the polishing pad 108 in a state where the top ring 116 is rotated around a rotation axis that is eccentric from the rotation axis of the polishing table 110. As a result, the substrate 102 is polished by the polishing pad 108 and planarized.

(First embodiment)
Next, the abrasive fluid supply device of the first embodiment will be described. FIG. 2 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the first embodiment.

As shown in FIG. 2, the abrasive liquid supply device 200 supplies an abrasive liquid pipe 210 for supplying (conveying) the polishing abrasive liquid 205 to a polishing table 110 having a polishing surface (polishing pad 108) for polishing the substrate 102. And a tank 220 for storing the polishing abrasive liquid 205, and a pump 230 that pressurizes the polishing abrasive liquid stored in the tank 220 and supplies it to the polishing pad 108 via the abrasive liquid pipe 210. An inverter 235 is connected to the pump 230, and the pump 230 is driven at a rotational speed set by the inverter 235.

  The abrasive liquid supply device 200 includes an ultrasonic flowmeter 240 that measures the flow rate of the polishing abrasive liquid 205 that flows through the abrasive liquid pipe 210 and a control unit 250 that controls each component of the abrasive liquid supply apparatus 200. Prepare. The ultrasonic flowmeter 240 transmits ultrasonic waves from the upstream side to the downstream side of the flow of the polishing abrasive liquid 205 and transmits ultrasonic waves from the downstream side to the upstream side of the polishing abrasive liquid 205. Information measured by the ultrasonic flowmeter 240 is output to the meter clock 245. The timepiece 245 measures the flow rate of the polishing abrasive liquid based on the difference between the arrival time of the ultrasonic wave from the upstream side to the downstream side and the arrival time of the ultrasonic wave from the downstream side to the upstream side. A signal of the flow rate of the polishing abrasive fluid 205 measured by the ultrasonic flow meter and clock 245 is output to the control unit 250.

  The abrasive liquid supply apparatus 200 includes an orifice 260 provided on the downstream side of the ultrasonic flowmeter 240 of the abrasive liquid pipe 210. The orifice 260 narrows the opening degree of the abrasive fluid pipe 210 on the downstream side of the ultrasonic flowmeter 240 of the abrasive fluid pipe 210.

  The abrasive liquid supply apparatus 200 includes a circulation pipe 270 that branches from a branch point 215 upstream of the ultrasonic flowmeter 240 of the abrasive liquid pipe 210 and returns (circulates) the polishing abrasive liquid 205 to the tank 220. The abrasive fluid supply apparatus 200 includes an orifice 280 that is provided in the circulation pipe 270 and narrows the opening degree of the circulation pipe 270. The circulation pipe 270 is a pipe for circulating the polishing abrasive liquid 205 when the polishing abrasive liquid 205 is not supplied onto the polishing pad 108.

  In addition, the abrasive liquid supply device 200 is provided between the branch point 215 of the abrasive liquid pipe 210 and the ultrasonic flowmeter 240, the supply valve 290 that opens and closes the abrasive liquid pipe 210, and the branch point 215 of the circulation pipe 270. A circulation valve 295 which is provided between the orifice 280 and opens and closes the circulation pipe 270. The supply valve 290 and the circulation valve 295 are used to switch between a mode for supplying the polishing abrasive liquid to the polishing table 110 and a mode for circulating the polishing abrasive liquid to the tank 220, and based on a control signal from the control unit 250. Opened and closed.

  The control unit 250 is orthogonal to the flow direction of the polishing abrasive fluid 205 in the measurement region (on the ultrasonic wave transmission path in the abrasive fluid piping 210) in which the flow rate of the polishing abrasive fluid 205 is measured by the ultrasonic flowmeter 240. The pressure of the polishing abrasive liquid 205 in the abrasive liquid pipe 210 is controlled so that the polishing abrasive liquid 205 and bubbles are not mixed on the surface. In other words, the control unit 250 does not generate non-uniform bubbles in the measurement region in which the flow rate of the polishing abrasive liquid 205 is measured by the ultrasonic flowmeter 240 (polishing on a surface orthogonal to the flow direction of the polishing abrasive liquid 205. The pressure of the polishing abrasive liquid 205 in the abrasive liquid pipe 210 is controlled so that the abrasive liquid 205 and bubbles are not mixed. Specifically, in the measurement region, the control unit 250 does not generate non-uniform bubbles in the pressure of the polishing abrasive liquid 205 (the polishing abrasive liquid 205 and the bubbles are formed on a surface orthogonal to the flow direction of the polishing abrasive liquid 205. The number of rotations of the pump 230 is controlled so that the pressure is not mixed.

  This point will be described. FIG. 3 is a diagram for explaining uniform bubbles and non-uniform bubbles, and FIG. 4 is a diagram illustrating an example in which bubbles stay in the flow rate measurement region. 3A is a schematic diagram of a transverse section and a longitudinal section showing an example when uniform bubbles are generated, and FIG. 3B is a transverse section showing an example when non-uniform bubbles are generated. It is a schematic diagram of a longitudinal section.

In FIG. 3A, bubbles 215 are generated in the abrasive liquid pipe 210, but these bubbles 215 exist on the entire surface 217 perpendicular to the flow direction of the polishing abrasive liquid 205. On the surface 217, the polishing abrasive fluid 205 and the bubbles 215 are not mixed. In the present specification, such bubbles 215 are defined as “uniform bubbles”. In this case, even if bubbles 215 are generated in the abrasive liquid pipe 210, the bubbles 215 flow in the abrasive liquid pipe 210 together with the polishing abrasive liquid 205, and therefore do not stay in the abrasive liquid pipe 210. As a result, there is no possibility of affecting the flow measurement by the ultrasonic flowmeter 240.

  On the other hand, in FIG. 3B, bubbles 215 are generated in the abrasive liquid pipe 210, and the bubbles 215 and the polishing abrasive liquid 205 are formed on a surface 217 orthogonal to the flow direction of the polishing abrasive liquid 205. It is mixed. In the present specification, such bubbles 215 are defined as “non-uniform bubbles”. In this case, the bubbles 215 may stay in the abrasive liquid pipe 210. If the bubble 215 stays in the abrasive pipe 210, the ultrasonic wave transmitted from the ultrasonic flowmeter 240 may be reflected by the bubble 215 and not reach the receiving side. As a result, there is a possibility that the flow rate of the polishing abrasive liquid cannot be measured by the ultrasonic flowmeter 240.

  As an example of the case where bubbles stay in the flow rate measurement region, as shown in FIG. 4, there is a case where the abrasive liquid pipe 210 is bent into a crank shape. That is, the abrasive liquid pipe 210 is continuous with the first abrasive liquid pipe 210-1 and the first abrasive liquid pipe 210-1, and in a direction orthogonal to the extending direction of the first abrasive liquid pipe 210-1. Second abrasive liquid pipe 210-2 that extends, and third abrasive that is continuous with second abrasive liquid pipe 210-2 and extends in a direction perpendicular to the extending direction of second abrasive liquid pipe 210-2. Consider a case including the liquid pipe 210-3.

  In this case, for example, the ultrasonic flowmeter 240 transmits ultrasonic waves from the most upstream part of the second abrasive liquid pipe 210-2 to the most downstream part, and at the most downstream part of the second abrasive liquid pipe 210-2. The ultrasonic wave is transmitted from the most upstream part to the most upstream part, and the flow rate of the polishing abrasive liquid 205 is measured based on the difference in the arrival times.

  If non-uniform bubbles are generated inside the polishing abrasive fluid 205, as shown in FIG. 4, the bubbles 215 are bonded to the first abrasive fluid pipe 210-1 and the second abrasive fluid pipe 210-2. May remain at the corners at the corners or at the corners at the joint between the second abrasive liquid pipe 210-2 and the third abrasive liquid pipe 210-3. In such a case, the staying bubble 215 continues to stay on the transmission path of the ultrasonic wave transmitted by the ultrasonic flowmeter 240, so that the flow measurement is caused by the reflection of the ultrasonic wave by the bubble 215 and the like. It may not be performed correctly. In FIG. 4, the case where the abrasive liquid pipe 210 is formed in a crank shape is given as an example. However, the present invention is not limited to this. For example, even if the abrasive liquid pipe 210 has a straight shape, it is non-uniform. When bubbles are generated, the bubbles may stay in the flow rate measurement region (on the ultrasonic wave transmission path in the abrasive fluid pipe 210).

  In contrast, in the present embodiment, since the orifice 260 is provided in the abrasive liquid pipe 210, the diameter of a part of the abrasive liquid pipe 210 is reduced. Then, the control unit 250 controls the number of revolutions of the pump 230 via the inverter 235 so that the pressure of the polishing abrasive liquid 205 becomes a pressure that does not generate uneven bubbles in the measurement region. Here, the number of rotations of the pump 230 so that the pressure of the polishing abrasive liquid 205 in the measurement region becomes a pressure at which non-uniform bubbles are not generated is set in advance for each abrasive liquid supply device 200 by an experiment or the like. 250 drives the pump 230 at a preset rotation speed. As a result, the generation of non-uniform bubbles in the measurement region in the abrasive fluid pipe 210 is suppressed, so that the bubbles are less likely to stay in the abrasive fluid tube 210, and as a result, the accuracy of flow rate detection is reduced. Is suppressed. In addition, since there is a measurement region between the pump 230 and the orifice 260, the pressure drop of the polishing abrasive liquid in the measurement region is suppressed, and the pressure of the polishing abrasive liquid in the measurement region is maintained at a pressure at which non-uniform bubbles are not generated. be able to.

  Next, a processing flow of the substrate processing apparatus according to the first embodiment will be described. FIG. 5 is a diagram illustrating a processing flow of the substrate processing apparatus according to the first embodiment.

In this processing flow, first, the orifice 260 is provided in the abrasive fluid pipe 210 and the circulation pipe 270.
, 280 are attached (step S101). This process is performed at the first installation time of the abrasive liquid supply device 200, and thus need not be performed from the next time. Further, in the present embodiment, an example in which the circulation pipe 270 is provided and the polishing abrasive liquid 205 is circulated when the polishing abrasive liquid 205 is not supplied to the polishing table 110 is shown, but the present invention is not limited thereto, and the circulation pipe 270 is not provided. You can also. In this case, the orifice 280 need not be installed. The orifice 280 is provided downstream of the circulation valve 295. That is, by providing the orifice 280 downstream of the circulation valve 295, the pump 230 and the orifice can be connected even when the supply valve 290 is “closed” and the circulation valve 295 is “open” (circulation mode) and the abrasive fluid is being circulated. The pressure between 280 does not drop. Therefore, even when the supply valve 290 is “open” and the circulation valve is “closed” (supply mode) from the circulation mode, the pressure of the supply valve 290 and the pump 230 can be maintained high. Even when the operation mode is changed from the supply mode to the supply mode, it is possible to prevent the pressure drop of the abrasive liquid in the measurement region.

  Subsequently, the control unit 250 drives the pump 230 at a predetermined rotational speed (step S102). Specifically, the control unit 250 is preset with the number of revolutions of the pump 230 so that the pressure of the polishing abrasive liquid in the measurement region becomes a pressure at which non-uniform bubbles are not generated in the polishing abrasive liquid. A number of command signals are transmitted to the inverter 235. Inverter 235 drives pump 230 at a rotational speed based on the command signal transmitted from control unit 250.

  Subsequently, the control unit 250 controls the supply valve 290 to “open” and the circulation valve 295 to “close” (step S103). As a result, the polishing abrasive liquid 205 discharged from the pump 230 is supplied to the polishing table 110 via the abrasive liquid pipe 210.

  Subsequently, the control unit 250 determines whether or not an error has occurred in the ultrasonic flow meter 240 (step S104). The ultrasonic flowmeter 240 issues an error signal indicating that the flow rate of the polishing abrasive liquid 205 cannot be measured due to the bubbles 215 or some other influence when the ultrasonic flowmeter 240 cannot receive the ultrasonic wave even if it is transmitted. The controller 250 determines whether or not an error has occurred in the ultrasonic flowmeter 240 depending on whether or not this error signal has been received.

  If it is determined that an error has occurred in the ultrasonic flowmeter 240 (step S104, Yes), the control unit 250 generates an alarm (step S105) and interrupts the process (step S106). That is, the polishing process is interrupted regardless of whether or not the actual polishing abrasive fluid flow rate is normal. In this embodiment, the pressure of the polishing abrasive liquid is controlled so that non-uniform bubbles are not generated in the measurement region. However, this process is provided because an error may occur in the flow rate measurement for some reason. ing.

  On the other hand, if the controller 250 determines that no error has occurred in the ultrasonic flowmeter 240 (No in step S104), the controller 250 polishes the substrate 102 (step S107).

  Subsequently, the control unit 250 determines whether or not the polishing is finished (step S108). The determination as to whether or not the polishing of the substrate 102 has ended can be made based on, for example, a change in torque current of the first electric motor 112 or the second electric motor 118.

  When it is determined that the polishing of the substrate 102 has not been completed (No at Step S108), the control unit 250 repeats the polishing process until it is determined that the polishing has been completed. On the other hand, if the controller 250 determines that the polishing of the substrate 102 has been completed (step S108, Yes), the controller 250 controls the supply valve 290 to “Close” and the circulation valve 295 to “Open”. (Step S109). As a result, the polishing abrasive fluid 205 discharged from the pump 230 is circulated to the tank 220 via the circulation pipe 270.

  As described above, according to the first embodiment, the flow resistance is added to the abrasive liquid pipe 210 (and the circulation pipe 270) by attaching the orifice 260 (280) to the abrasive liquid pipe 210 (and the circulation pipe 270). Can do. Then, in the flow rate measurement region, the pump 230 is driven at a preset rotation speed so that the pressure of the polishing abrasive liquid becomes a pressure at which non-uniform bubbles are not generated in the polishing abrasive liquid. As a result, non-uniform bubbles as shown in FIG. 3B are generated in the flow rate measurement region of the polishing fluid pipe 210 (the polishing abrasive fluid 205 and the bubbles on the surface orthogonal to the flow direction of the polishing abrasive fluid 205). Can be suppressed). As a result, it is possible to suppress air bubbles from staying in the abrasive liquid pipe 210 in the flow rate measurement region, and thus it is possible to suppress deterioration in flow rate detection accuracy due to air bubbles generated in the polishing abrasive liquid. Can do.

  In this embodiment, the example in which the orifice 260 (280) is attached to the abrasive liquid pipe 210 (and the circulation pipe 270) is shown, but the present invention is not limited to this, and the resistance of the abrasive liquid pipe 210 (and the circulation pipe 270) is not limited. Such variable orifices, pinch valves and the like can also be provided.

(Second Embodiment)
Next, the abrasive fluid supply device of the second embodiment will be described. FIG. 6 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the second embodiment. The second embodiment is different from the first embodiment in that the orifice 260 provided in the abrasive liquid pipe 210 is replaced with a variable orifice, and a pressure sensor and a bubble sensor are added to the abrasive liquid pipe 210. Common to the first embodiment. Therefore, differences from the first embodiment will be mainly described, and description of portions overlapping with the first embodiment will be omitted.

  As shown in FIG. 6, the abrasive liquid supply device 300 of the second embodiment includes a variable orifice 310 that can adjust the opening degree of the abrasive liquid pipe 210 on the downstream side of the ultrasonic flowmeter 240 of the abrasive liquid pipe 210. The variable orifice 310 is connected to the electropneumatic regulator 315, and the electropneumatic regulator 315 is connected to the control unit 250. The electropneumatic regulator 315 converts a control signal (electrical signal) output from the control unit 250 into air pressure and outputs the air pressure to the variable orifice 310, and adjusts the opening of the variable orifice 310 by air pressure.

  The abrasive liquid supply device 300 is provided on the upstream side of the ultrasonic flowmeter 240 in the abrasive liquid pipe 210, specifically, between the supply valve 290 and the ultrasonic flowmeter 240, and is provided in the abrasive liquid pipe 210. A pressure sensor 320 for detecting pressure is provided. The pressure detected by the pressure sensor 320 is output to the control unit 250.

  The abrasive liquid supply device 300 is provided upstream of the ultrasonic flowmeter 240 in the abrasive liquid pipe 210, specifically, between the pressure sensor 320 and the ultrasonic flowmeter 240, and is provided in the abrasive liquid pipe 210. A bubble sensor 330 is provided for detecting whether or not bubbles are generated. For example, the bubble sensor 330 outputs light into the abrasive liquid pipe 210 and determines whether or not bubbles are generated based on the level of intensity of light received by the light receiving unit. For example, if bubbles are generated in the polishing abrasive liquid 205, the light reception level is lower than a predetermined threshold value, and thus it is detected that bubbles are generated. A signal indicating the presence or absence of bubbles detected by the bubble sensor 330 is output to the control unit 250. A plurality of bubble sensors 330 may be provided between the ultrasonic flowmeter 240 and the pressure sensor 320.

  Next, a processing flow of the substrate processing apparatus according to the second embodiment will be described. FIG. 7 is a diagram illustrating a processing flow of the substrate processing apparatus according to the second embodiment.

In this processing flow, first, a variable orifice is provided in the abrasive fluid pipe 210, and an orifice 280 is provided in the circulation pipe 270 (step S201). This process is performed at the first installation time of the abrasive liquid supply device 200, and thus need not be performed from the next time. Further, in the present embodiment, an example in which the circulation pipe 270 is provided and the polishing abrasive liquid 205 is circulated when the polishing abrasive liquid 205 is not supplied to the polishing table 110 is shown, but the present invention is not limited thereto, and the circulation pipe 270 is not provided. You can also. In this case, the orifice 280 need not be installed.

  Subsequently, the control unit 250 drives the pump 230 at a predetermined rotational speed (step S202). Specifically, control unit 250 transmits a command signal having a preset rotation speed to inverter 235. Inverter 235 drives pump 230 at a rotational speed based on the command signal transmitted from control unit 250.

  Subsequently, the control unit 250 controls the supply valve 290 to “open” and the circulation valve 295 to “close” (step S203). As a result, the polishing abrasive liquid 205 discharged from the pump 230 is supplied to the polishing table 110 via the abrasive liquid pipe 210.

  Subsequently, the control unit 250 controls the pump rotation speed so that the pressure in the abrasive fluid piping becomes a target value (step S204). Specifically, the control unit 250 controls the rotation speed of the pump 230 so that the pressure detected by the pressure sensor 320 becomes a target value (for example, 0.1 MPa).

  Subsequently, the control unit 250 controls the variable orifice so that the flow rate of the polishing abrasive liquid becomes a target value (step S205). Specifically, the control unit 250 controls the valve opening degree of the variable orifice 310 so that the flow rate of the polishing abrasive liquid measured by the ultrasonic flowmeter 240 becomes a target value (for example, 150 mL / min).

  Subsequently, the control unit 250 determines whether or not the pressure detected by the pressure sensor 320 and the flow rate measured by the ultrasonic flowmeter 240 have reached a target value (step S206).

  When it is determined that the pressure detected by the pressure sensor 320 and the flow rate measured by the ultrasonic flowmeter 240 are not the target value (step S206, No), the control unit 250 sets the first target value. Steps S204 and 205 are repeated until it is determined that it has become.

  That is, even if the rotational speed of the pump 230 is controlled so that the pressure becomes a target value (for example, 0.1 MPa) in step S204, the pressure changes if the valve opening degree of the variable orifice 310 is controlled in step S205. . On the other hand, even if the valve opening degree of the variable orifice 310 is controlled so that the flow rate becomes the target value in step S205, the flow rate changes when the number of rotations of the pump 230 is changed thereafter. Therefore, the control unit 250 repeats steps S204 and 205 until it is determined that the pressure detected by the pressure sensor 320 and the flow rate measured by the ultrasonic flowmeter 240 have reached the target value.

  On the other hand, if it is determined that the pressure detected by the pressure sensor 320 and the flow rate measured by the ultrasonic flowmeter 240 have reached the target values (step S206, Yes), the control unit 250 determines whether bubbles have been detected. Is determined (step S207). Specifically, if the light receiving level of the optical signal transmitted from the bubble sensor 330 is equal to or higher than a predetermined threshold, the control unit 250 determines that no bubbles are generated in the polishing abrasive liquid, and performs a predetermined operation. If it is lower than the threshold value, it is determined that bubbles are generated in the polishing liquid.

If it determines with the bubble having been detected (step S207, Yes), the control part 250 will control a pump rotation speed so that the pressure in abrasive fluid piping may become the present pressure + (alpha) (step S208). Specifically, the control unit 250 controls the rotation speed of the pump 230 so that the pressure detected by the pressure sensor 320 becomes the current pressure + α (for example, 0.12 MPa when α = 0.02 MPa). To do. Here, the target pressure value in the abrasive fluid piping is updated. That is, when the bubble sensor 330 determines that bubbles are generated, the control unit 250 increases the pressure of the polishing abrasive liquid by increasing the number of revolutions of the pump 230. In this embodiment, an example in which the number of revolutions of the pump is increased in order to increase the pressure of the polishing abrasive liquid has been described. However, the present invention is not limited to this, and the polishing abrasive is reduced by reducing (squeezing) the opening of the variable orifice 310. The pressure of the liquid may be increased. Further, both the pump 230 and the variable orifice 310 may be controlled.

  Subsequently, the control unit 250 controls the variable orifice so that the flow rate of the polishing abrasive liquid becomes a target value (step S209). Specifically, the controller 250 opens the valve opening of the variable orifice 310 so that the flow rate of the polishing abrasive liquid measured by the ultrasonic flowmeter 240 becomes the same target value (for example, 150 mL / min) as that in step S205. To control.

  Subsequently, the control unit 250 determines whether or not the pressure detected by the pressure sensor 320 becomes the updated target value, and the flow rate measured by the ultrasonic flowmeter 240 reaches the target value (step S210). ).

  When it is determined that the pressure detected by the pressure sensor 320 is not the target value or the flow rate measured by the ultrasonic flowmeter 240 is not the target value (No in step S210), the control unit 250 determines that the pressure detected by the pressure sensor 320 is not the target value. Steps S208 and S209 are repeated until it is determined that the pressure reaches the target value and the flow rate reaches the target value.

  When the controller 250 determines that the pressure detected by the pressure sensor 320 has reached the target value and the flow rate measured by the ultrasonic flowmeter 240 has reached the first target value (step S210, Yes), The process returns to step S207 and continues.

  If it is determined that bubbles are still detected even if the pressure of the polishing abrasive liquid is + α (step S207, Yes), the control unit 250 repeats steps S208 to S210 again to increase the pressure of the polishing abrasive liquid. That is, in view of the fact that the higher the liquid pressure of the polishing abrasive liquid 205, the greater the amount of gas dissolved in the liquid, in this embodiment, the polishing abrasive liquid 205 in the abrasive liquid pipe 210 is increased in pressure to the extent that bubbles are not generated. Is done. Note that the pressure of the polishing abrasive liquid 205 can be increased with the maximum pressure (for example, 0.2 MPa) as the upper limit. If the target pressure value exceeds the maximum pressure, there is a risk that the flow rate of the polishing abrasive fluid 205 will increase excessively or the abrasive fluid piping 210 will rupture, so an alarm may be issued and the abrasive fluid supply stopped. it can.

  On the other hand, if it is determined in step S207 that no bubbles are detected (No in step S207), the controller 250 performs the polishing process on the substrate 102 (step S211).

  Subsequently, the control unit 250 determines whether or not the polishing is finished (step S212). The determination as to whether or not the polishing of the substrate 102 has ended can be made based on, for example, a change in torque current of the first electric motor 112 or the second electric motor 118.

  If it is determined that the polishing of the substrate 102 has not been completed (No in step S212), the control unit 250 repeats the polishing process until it is determined that the polishing has been completed. On the other hand, if the controller 250 determines that the polishing of the substrate 102 has been completed (step S212, Yes), the controller 250 controls the supply valve 290 to “Close” and the circulation valve 295 to “Open”. (Step S213). As a result, the polishing abrasive fluid 205 discharged from the pump 230 is circulated to the tank 220 via the circulation pipe 270.

  As described above, according to the second embodiment, the polishing abrasive liquid 205 in the abrasive liquid pipe 210 is increased to such a level that no bubbles are generated, so that generation of bubbles in the polishing abrasive liquid 205 can be suppressed. . As a result, it is possible to suppress air bubbles from staying in the abrasive liquid pipe 210 in the flow rate measurement region, and thus it is possible to suppress deterioration in flow rate detection accuracy due to air bubbles generated in the polishing abrasive liquid. Can do.

(Third embodiment)
Next, the abrasive fluid supply device of the third embodiment will be described. FIG. 8 is a diagram schematically illustrating a substrate processing apparatus including the abrasive liquid supply apparatus according to the third embodiment. The third embodiment is different from the first embodiment in that instead of providing the orifices 260 and 280, a pipe having a reduced diameter is connected to the downstream side of the abrasive liquid pipe and the circulation pipe, and the others are the first embodiment. And in common. Therefore, differences from the first embodiment will be mainly described, and description of portions overlapping with the first embodiment will be omitted.

  As shown in FIG. 8, in the abrasive liquid supply apparatus 400 of the third embodiment, the pump 230 and the ultrasonic flowmeter 240 are connected by a first abrasive liquid pipe 410-1 (for example, 3/8 inch). Further, the ultrasonic flowmeter 240 and the pipe joint 420 are connected by a second abrasive liquid pipe 410-2 (for example, 1/4 inch) having a diameter smaller than that of the first abrasive liquid pipe 410-1. Further, on the downstream side of the pipe joint 420, a third abrasive liquid pipe 410-3 having a smaller diameter than the second abrasive liquid pipe 410-2 and having a discharge port for discharging the polishing abrasive liquid 205 onto the polishing table 110. (For example, 1/8 inch) is connected.

  On the other hand, on the circulation pipe side, the branch point 215 and the pipe joint 430 are connected by a first circulation pipe 470-1 (for example, 3/8 inch). Further, on the downstream side of the pipe joint 430, a second circulation pipe 470-2 (for example, having a discharge port for discharging the polishing abrasive liquid 205 to the tank 220 having a smaller diameter than the first abrasive liquid pipe 470-1). 1/8 inch) is connected.

  Next, a processing flow of the substrate processing apparatus according to the third embodiment will be described. FIG. 9 is a diagram illustrating a processing flow of the substrate processing apparatus according to the third embodiment.

  In this processing flow, first, reduced diameter piping is attached to the abrasive fluid piping and the circulation piping (step S301). Specifically, the second abrasive liquid pipe 410-2 and the third abrasive liquid pipe 410-3 are attached to the downstream side of the first abrasive liquid pipe 410-1, and the first circulation pipe 470-1 is connected. A second circulation pipe 470-2 is attached to the downstream side. This process is performed at the first installation time of the abrasive liquid supply device 400, and thus need not be performed from the next time. Further, in the present embodiment, an example in which a circulation pipe is provided and the polishing abrasive liquid 205 is circulated when the polishing abrasive liquid 205 is not supplied to the polishing table 110 is shown, but the present invention is not limited thereto, and the circulation pipe 270 is not provided. You can also.

  Subsequently, the control unit 250 drives the pump 230 at a predetermined rotation speed (step S302). Specifically, the control unit 250 is preset with the number of revolutions of the pump 230 so that the pressure of the polishing abrasive liquid in the measurement region becomes a pressure at which non-uniform bubbles are not generated in the polishing abrasive liquid. A number of command signals are transmitted to the inverter 235. Inverter 235 drives pump 230 at a rotational speed based on the command signal transmitted from control unit 250.

  Subsequently, the control unit 250 controls the supply valve 290 to “open” and controls the circulation valve 295 to “close” (step S303). As a result, the polishing abrasive liquid 205 discharged from the pump 230 is supplied to the polishing table 110 via the abrasive liquid pipe 210.

Subsequently, the control unit 250 determines whether or not an error has occurred in the ultrasonic flowmeter 240 (step S304). The ultrasonic flowmeter 240 issues an error signal indicating that the flow rate of the polishing abrasive liquid 205 cannot be measured due to the bubbles 215 or some other influence when the ultrasonic flowmeter 240 cannot receive the ultrasonic wave even if it is transmitted. The controller 250 determines whether or not an error has occurred in the ultrasonic flowmeter 240 depending on whether or not this error signal has been received.

  If it is determined that an error has occurred in the ultrasonic flowmeter 240 (step S304, Yes), the control unit 250 generates an alarm (step S305) and interrupts the process (step S306). That is, the polishing process is interrupted regardless of whether or not the actual polishing abrasive fluid flow rate is normal. In this embodiment, the pressure of the polishing abrasive liquid is controlled so that non-uniform bubbles are not generated in the measurement region. However, this process is provided because an error may occur in the flow rate measurement for some reason. ing.

  On the other hand, if the controller 250 determines that no error has occurred in the ultrasonic flowmeter 240 (No in step S304), the controller 250 performs a polishing process on the substrate 102 (step S307).

  Subsequently, the control unit 250 determines whether or not the polishing is finished (step S308). The determination as to whether or not the polishing of the substrate 102 has ended can be made based on, for example, a change in torque current of the first electric motor 112 or the second electric motor 118.

  If it is determined that the polishing of the substrate 102 has not been completed (No at Step S308), the control unit 250 repeats the polishing process until it is determined that the polishing has been completed. On the other hand, when the controller 250 determines that the polishing of the substrate 102 has been completed (step S308, Yes), the controller 250 controls the supply valve 290 to “Close” and the circulation valve 295 to “Open”. (Step S309). As a result, the polishing abrasive fluid 205 discharged from the pump 230 is circulated to the tank 220 via the circulation pipe 270.

  As described above, in the present embodiment, the abrasive fluid pipe (the second abrasive pipe having a diameter smaller than that of the first abrasive fluid pipe 410-1 is provided on the downstream side of the first abrasive fluid pipe 410-1 provided with the ultrasonic flowmeter 240. Abrasive fluid pipe 410-2 and a third abrasive fluid pipe 410-3) are provided. Also in the circulation pipe, a circulation pipe having a smaller diameter than the first circulation pipe 470-1 (second circulation pipe 470-2 is provided on the downstream side of the first circulation pipe 470-1. The flow resistance can be added to the abrasive liquid pipe 410 (and the circulation pipe 470) without providing the orifices 260 and 280 as in the first embodiment, and the pressure of the polishing abrasive liquid is increased in the flow rate measurement region. Then, the pump 230 is driven at a preset number of rotations so as to obtain a pressure at which non-uniform bubbles are not generated in the polishing abrasive liquid, whereby in the flow rate measurement region of the abrasive liquid pipe 210, as shown in FIG. It is possible to suppress the generation of non-uniform bubbles as shown (mixing of the polishing abrasive fluid 205 and bubbles on the surface orthogonal to the flow direction of the polishing abrasive fluid 205). Air bubbles in the liquid pipe 210 can be prevented from staying, due to bubbles generated in the abrasive liquid in the accuracy of the flow rate detection can be suppressed.

DESCRIPTION OF SYMBOLS 100 Substrate processing apparatus 102 Substrate 108 Polishing pad 110 Polishing table 116 Top ring 200, 300, 400 Abrasive liquid supply apparatus 205 Polishing abrasive liquid 210 Abrasive liquid piping 215 Bubble 230 Pump 240 Ultrasonic flowmeter 250 Control part 260, 280 Orifice 270 Circulation Piping 290 Supply valve 295 Circulating valve 310 Variable orifice 320 Pressure sensor 330 Bubble sensor

Claims (11)

A polishing liquid pipe for supplying a polishing polishing liquid to a polishing table having a polishing surface for polishing the substrate;
A pump for supplying the polishing abrasive liquid to the polishing table via the abrasive liquid pipe;
A flow meter for measuring the flow rate of the polishing abrasive fluid flowing through the abrasive fluid piping;
In the measurement area where the flow rate of the polishing abrasive liquid is measured by the flow meter, the polishing abrasive in the abrasive liquid pipe is not mixed on the surface orthogonal to the flow direction of the polishing abrasive liquid. A control unit for controlling the pressure of the liquid;
Equipped with a,
In the measurement region, the control unit rotates the pump so that the pressure of the polishing abrasive liquid becomes a pressure at which the polishing abrasive liquid and bubbles do not coexist on a surface orthogonal to the flow direction of the polishing abrasive liquid. Control the number,
The abrasive liquid pipe has a first diameter and a first abrasive liquid pipe provided with the flowmeter, and is connected to the downstream side of the first abrasive liquid pipe, and has a diameter smaller than the first diameter. abrasive liquid supply device according to claim Rukoto comprises a second abrasive liquid pipe having a second diameter, the.   A polishing liquid pipe for supplying a polishing polishing liquid to a polishing table having a polishing surface for polishing the substrate;
  A pump for supplying the polishing abrasive liquid to the polishing table via the abrasive liquid pipe;
  A flow meter for measuring the flow rate of the polishing abrasive fluid flowing through the abrasive fluid piping;
  In the measurement area where the flow rate of the polishing abrasive liquid is measured by the flow meter, the polishing abrasive in the abrasive liquid pipe is not mixed on the surface orthogonal to the flow direction of the polishing abrasive liquid. A control unit for controlling the pressure of the liquid;
  With
  Branching from the upstream side of the flowmeter of the abrasive fluid piping, further comprising a circulation piping for circulating the abrasive abrasive fluid to the suction side of the pump,
  An abrasive liquid supply device, wherein the circulation pipe is provided with an orifice for narrowing the opening degree of the circulation pipe.   In the abrasive fluid supply apparatus of claim 2,
  In the measurement region, the control unit rotates the pump so that the pressure of the polishing abrasive liquid becomes a pressure at which the polishing abrasive liquid and bubbles do not coexist on a surface orthogonal to the flow direction of the polishing abrasive liquid. Control the number,
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus according to claim 2 or 3,
  A variable orifice capable of adjusting the opening of the abrasive fluid pipe on the downstream side of the flowmeter of the abrasive fluid pipe;
  In the measurement region, the controller controls the variable orifice so that the pressure of the polishing abrasive liquid becomes a pressure at which the polishing abrasive liquid and bubbles do not coexist on a surface orthogonal to the flow direction of the polishing abrasive liquid. Control the opening,
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus according to claim 3,
  Further comprising an orifice for narrowing the opening degree of the abrasive pipe on the downstream side of the flowmeter of the abrasive pipe,
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus according to claim 3,
  The abrasive liquid pipe has a first diameter and a first abrasive liquid pipe provided with the flowmeter, and is connected to the downstream side of the first abrasive liquid pipe, and has a diameter smaller than the first diameter. A second abrasive liquid pipe having a diameter of 2.
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus according to claim 3 or 4,
  A pressure detector for detecting a pressure upstream of the flowmeter of the abrasive fluid pipe;
  The control unit is configured so that the pressure detected by the pressure detector is a pressure at which the polishing abrasive liquid and bubbles do not coexist on a surface orthogonal to the flow direction of the polishing abrasive liquid in the measurement region. Controlling the number of rotations or the opening of the variable orifice,
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus of claim 2,
  The control unit controls the pressure of the polishing abrasive liquid in the abrasive liquid pipe so that bubbles do not occur in the polishing abrasive liquid in a measurement region in which the flow rate of the polishing abrasive liquid is measured by the flow meter.
  A polishing liquid supply apparatus characterized by the above.   In the abrasive fluid supply apparatus according to claim 8,
  A bubble detector for detecting whether or not bubbles are generated in the abrasive fluid pipe on the upstream side of the flowmeter of the abrasive fluid pipe;
  If the bubble detector determines that bubbles are generated by the bubble detector, the controller increases the rotational speed of the pump or the abrasive fluid pipe on the downstream side of the flow meter of the abrasive fluid pipe The pressure of the polishing abrasive liquid is increased by controlling the opening of the variable orifice that can adjust the opening of the
  A polishing liquid supply apparatus characterized by the above.   A polishing liquid pipe for supplying a polishing polishing liquid to a polishing table having a polishing surface for polishing the substrate;
  A pump for supplying the polishing abrasive liquid to the polishing table via the abrasive liquid pipe;
  A flow meter for measuring the flow rate of the polishing abrasive fluid flowing through the abrasive fluid piping;
  In the measurement area where the flow rate of the polishing abrasive liquid is measured by the flow meter, the polishing abrasive in the abrasive liquid pipe is not mixed on the surface orthogonal to the flow direction of the polishing abrasive liquid. A control unit for controlling the pressure of the liquid;
  With
  Branching from the upstream side of the flowmeter of the abrasive fluid piping, further comprising a circulation piping for circulating the abrasive abrasive fluid to the suction side of the pump,
  The circulation pipe includes a first circulation pipe having a first diameter, and a second circulation pipe connected to the downstream side of the first circulation pipe and having a second diameter smaller than the first diameter. A polishing liquid supply apparatus comprising:   The abrasive liquid supply device of claim 10;
  A polishing table having a polishing surface for polishing a substrate;
  A substrate holding unit that polishes the substrate by holding the substrate and pressing it against the polishing surface in a state where a polishing abrasive solution is supplied to the polishing table by the abrasive solution supply device;
  A substrate processing apparatus comprising: