Membrane failure detection system

Abstract

A grinding system includes a pressure system, a substrate carrier including a film, a first sensor, and a control system. The first compartment of the membrane is fluidly coupled to a pressure system. The first sensor is configured to monitor the pressure system and generate a first output based on a condition detected in the pressure system. A control system is coupled to the first sensor and configured to process the first output to produce a first processed output, the control system configured to compare the first processed output to a threshold to detect the presence of fluid in the pressure system.

Description

Technical Field

[0001] The specific embodiments described herein generally relate to semiconductor device manufacturing, and more particularly to chemical mechanical polishing (CMP) systems and related methods used in semiconductor device manufacturing. Background Art

[0002] Chemical mechanical polishing (CMP) is commonly used in the manufacture of high-density integrated circuits to planarize a material layer on a substrate, remove excess material from the surface of the underlying material layer, or both. In a typical CMP process, the substrate is held in a carrier head having a membrane that can be pressurized in the presence of a polishing fluid to press the back side of the substrate against a rotating polishing pad. A vacuum can be applied to the membrane to vacuum-adsorb the substrate to the carrier head. The polishing pad is typically formed of a polymeric material having a surface roughness that facilitates the delivery of the polishing fluid to the interface between the material surface of the substrate and the moving polishing pad disposed thereunder. The polishing fluid typically comprises an aqueous solution of one or more chemical components and nanoscale abrasive particles suspended in the aqueous solution, and is commonly referred to as a polishing fluid or polishing slurry.

[0003] Failure of the membrane, such as a hole or a tear, can compromise the pressure integrity of the membrane. A failed membrane can no longer be pressurized as needed during the polishing process, which may result in insufficient or uneven polishing, damage to the substrate, or cause the substrate to slip out during the polishing process and no longer engage with the membrane, thereby resulting in the scrapping of the entire substrate or the loss of the integrated circuit. A damaged membrane may not be able to vacuum-adsorb the substrate to the substrate carrier head, which may prevent the substrate from moving or cause the substrate to accidentally fall during transportation.

[0004] In addition, failure of the membrane can cause fluid (such as the polishing fluid) to undesirably enter the pneumatic devices of the CMP system. The entry of the fluid may damage the pneumatic devices, or may cause blockage or clogging of the flow paths in the pneumatic devices, thereby hindering CMP operation.

[0005] Therefore, there is a need in the art to detect membrane failure. Summary of the Invention

[0006] The present disclosure generally relates to monitoring and detecting the presence of contaminants in the pressure system of a polishing system using a sensor.

[0007] In one specific embodiment, the polishing system includes a pressure system, a substrate carrier including a membrane, a first sensor, and a control system. A first compartment of the membrane is fluidly coupled to the pressure system. The first sensor is configured to monitor the pressure system and generate a first output based on the conditions detected in the pressure system. The control system is coupled to the first sensor and is configured to process the first output to generate a first processed output, and the control system is configured to compare the first processed output with a threshold to detect the presence of fluid in the pressure system.

[0008] In one specific embodiment, a non-transitory computer-readable medium storing instructions that, when executed by one or more processors, cause a grinding system to perform an integrity test on a membrane positioned in a carrier head. The integrity test includes applying a vacuum to the membrane having a pressure system over a period of time, processing the output of a sensor monitoring the pressure system during that period to produce a processed output, and comparing the processed output with a threshold to determine whether there is liquid in the monitored pressure system.

[0009] In one specific embodiment, a method of operating a grinding system includes operating a carrier head that includes a membrane engageable with a substrate, wherein the internal pressure of the membrane is selectively changed by a pressure system. The method further includes: monitoring for failure of the membrane during operation using a sensor, wherein the monitoring includes: processing an output of the sensor to produce a processed output and comparing the processed output with a threshold based on gas in the pressure system. The method further includes: alerting a user of a failure of the membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Reference may be made to multiple specific embodiments to more particularly illustrate the present disclosure briefly summarized above and to more fully understand the above-described features of the present disclosure. The drawings illustrate some of the specific embodiments. It should be noted, however, that the drawings illustrate only exemplary specific embodiments and should not be considered as limiting the scope of the specific embodiments, and other equivalent specific embodiments may be recognized.

[0011] Figure 1A is a schematic side view of an exemplary grinding station according to one specific embodiment that can be used to practice the methods described herein.

[0012] Figure 1B is a schematic top view of a multi-station grinding system according to one specific embodiment that can be used to practice the methods described herein.

[0013] Figures 2A - 2H For illustrating the sensor and explaining various optical effects caused by the fluid flowing through the sensor. Figure 2A Shows an exemplary circuit diagram of the sensor. Figures 2B - 2C is a schematic diagram of a sensor sensing fluid in a flow path to illustrate the lens effect of the fluid. Figure 2D Shows the output of the sensor when detecting light to illustrate the lens effect and absorption effect of various oxide slurry mixtures. Figures 2E - 2F is a schematic diagram of a sensor sensing fluid in a flow path to illustrate the effect of total internal reflection of the fluid. Figures 2G - 2H is a schematic diagram of a sensor sensing fluid in a flow path to illustrate the effect of total internal reflection of the fluid.

[0014] Figure 3AIllustrates the output of the sensor.

[0015] Figure 3B Illustrates the output after the sensor processes.

[0016] Figure 3C Shows an exemplary algorithm for processing the sensor output.

[0017] Figure 4 Is a diagram showing a method for detecting a failed film with a sensor.

[0018] Figure 5 Is a diagram illustrating a method for testing film integrity.

[0019] For the sake of assisting understanding, the same reference numerals have been used as much as possible to label the same elements common to the drawings. It has been contemplated that the elements and features of a particular embodiment can be beneficially incorporated into other particular embodiments without further recitation. Detailed Description

[0020] The detailed embodiments of the present disclosure generally relate to a chemical mechanical polishing (CMP) system and process used in the manufacture of electronic devices. In particular, the detailed embodiments herein relate to detecting the entry of a polishing fluid into a flow path.

[0021] Figure 1A Is a schematic side view of an exemplary polishing station 100 according to a particular embodiment, which can be used to practice the methods described herein. Figure 1B Is a schematic top view of a multi-station polishing system 101 including a plurality of polishing stations 100, where each of the polishing stations 100a-c is substantially similar to Figure 1A the polishing station 100 described in Figure 1B In Figure 1A at least some of the components associated with the polishing station 100 described in

[0022] As Figure 1A shown, the polishing station 100 includes a platform 102, a polishing pad 106 disposed on and fixed to the platform 102, a fluid delivery arm 108 disposed above the polishing pad 106, a substrate carrier 110 (shown in cross-section), a pad conditioner assembly 112, a pressure system 150, and sensors 160a-c.

[0023] The substrate carrier 110 is suspended from a substrate transfer carriage 115 ( Figure 1B) on the carrier arm 113 such that the substrate carrier 110 is disposed above and facing the polishing pad 106. The substrate transfer carrier 115 is configured to move the substrate carrier 110 between the substrate loading stations 103 and / or between the polishing stations 100 of the multi-station polishing system 101, and thus move the substrate 122 adsorbed therein. Fluids may be present at the substrate loading station 103 and the polishing station 100. For example, polishing fluid may be present at the polishing station 100, and water may be present at the substrate loading station 103.

[0024] The pad conditioner assembly 112 may include a fixed abrasive conditioning disk 120, such as a diamond-impregnated disk, which may be pushed against the polishing pad 106 to rejuvenate its surface and / or remove polishing by-products or other debris therefrom. In other specific embodiments, the pad conditioner assembly 112 may include a brush (not shown).

[0025] The platform actuator 104 is coupled to the platform 102. During substrate polishing, the platform actuator 104 is configured to rotate the platform 102 about the platform axis A, and the substrate carrier 110 is disposed above and facing the platform 102. The substrate carrier 110 is configured to press the surface of the substrate 122 to be polished disposed therein against the polishing surface of the polishing pad 106 while rotating about the carrier axis B. In the presence of polishing fluid provided by the fluid delivery arm 108, the substrate 122 is pressed against the pad 106. The properties of the polishing fluid may be selected to obtain the desired polishing surface. The polishing fluid may be an abrasive slurry, such as an aqueous oxide slurry. The polishing fluid may contain abrasive particles, a pH regulator, and / or a chemically active ingredient to enable chemical mechanical polishing of the substrate 122. Generally, the rotating substrate carrier 110 oscillates between the inner radius and the outer radius of the platform 102 to partially reduce non-uniform wear of the surface of the polishing pad 106. Here, the substrate carrier 110 is rotated using a first actuator 124 coupled to the carrier arm 113, and vibrated using a second actuator 126 coupled to the carrier arm 113.

[0026] In some specific embodiments, the polishing station includes one or a combination of a polishing pad temperature sensor 114 (such as an infrared (IR) temperature sensor), a platform torque sensor 116, and a carrier torque sensor 118. Generally, the pad temperature sensor 114 is disposed above and facing the platform 102. The pad temperature sensor 114 is positioned to measure the polishing pad temperature directly behind (i.e., near the trailing edge of) the substrate carrier 110 along the direction of rotation of the platform 102. In some specific embodiments, the pad temperature sensor 114 is coupled to the carrier arm 113.

[0027] In some embodiments, the platform torque sensor 116 is coupled to the platform actuator 104 and the carrier torque sensor 118 is coupled to the first actuator 124. In some embodiments, the platform torque sensor 116 and the carrier torque sensor 118 are used to monitor the motor current for rotating the platform 102 and the substrate carrier 110 about their respective axes A, B. In some embodiments, the change in the motor current can be used to detect the grinding endpoint required in the grinding process. In other embodiments, the motor current can be used to detect the change in the amount of grinding fluid delivered to the surface of the grinding pad and the substrate 122 at any moment during grinding. For example, the higher friction sensed by the motor current may be caused by a decrease in the flow rate of the grinding fluid or a change in the composition of the grinding fluid.

[0028] The substrate carrier 110 may include a substrate carrier head 128, a carrier ring 130 coupled to the substrate carrier head 128, and a membrane 132 disposed radially inside the carrier ring 130 to provide a mounting surface for the substrate 122. During substrate grinding, the carrier ring 130 surrounds the substrate 122 to prevent the substrate 122 from slipping off the substrate carrier 110. The membrane 132 is coupled to the substrate carrier head 128 to define one or more compartments 134, such as a first compartment 134a, a second compartment 134b, and a third compartment 134c. In some embodiments having multiple compartments, as Figure 1A shown, each compartment 134 is isolated from the other compartments 134.

[0029] The pressure system 150 includes a pneumatic assembly 152, a rotary joint 154, and one or more flow paths 156. The pressure system 150 is configured to apply pressure or vacuum to the membrane 132. The internal pressure of the membrane 132 is selectively changed by the pressure system 150. As Figure 1A shown, the rotary joint 154 can be coupled to the carriage arm 113, such as coupled to the second actuator 126. The rotary joint 154 fluidly connects each compartment 134a, 134b, 134c to the pneumatic assembly 152. For example, as Figure 1AAs shown, the first compartment 134a is connected to the pneumatic assembly 152 via a first flow path 156a, the second compartment 134b is connected to the pneumatic assembly 152 via a second flow path 156b, and the third compartment 134c is connected to the pneumatic assembly 152 via a third flow path 156c. A portion of each of the flow paths 156a - c may be disposed in or on the rotary joint 154, the first actuator 124, the second actuator 126, and / or the carriage arm 113. When the substrate carrier 110 is rotated by the first actuator 124 and / or oscillated by the second actuator 126, the rotary joint 154 facilitates fluid communication between the pneumatic assembly 152 and the compartments 134a, 134b, 134c. The rotary joint 154 may also facilitate electrical and / or fluid connection from another fluid source, such as a hydraulic fluid source, to the first actuator 124, the second actuator 126, and / or the substrate carrier 110.

[0030] The pneumatic assembly 152 may include regulators, valves, and pumps (not shown) for pressurizing or applying a vacuum to the compartments 134a, 134b, 134c. The pneumatic assembly 152 may use a gas, such as clean dry air (CDA) or nitrogen. The pneumatic assembly 152 may include independent pressure sources and vacuum sources for each of the compartments 134a, 134b, 134c. The pneumatic assembly 152 may independently control the pressure in each of the compartments 134a, 134b, 134c. The pressure in each of the compartments 134a, 134b, 134c may be different to facilitate the distribution of the force applied by the membrane 132 on the substrate 122. In some embodiments, the grinding station 100 includes a first pressure sensor 119a in communication with the first flow path 156a to monitor the pressure in the first compartment 134a, a second pressure sensor 119b in communication with the second flow path 156b to monitor the pressure in the second compartment 134b, and a third pressure sensor 119c in communication with the third flow path 156c to monitor the pressure in the third compartment 134c. In some embodiments, the multi - station grinding system 101 may have a pneumatic assembly 152 for each grinding station 100. In some embodiments, the multi - station grinding system 101 may have a single pressure system 150 that includes dedicated pneumatic assemblies 152, rotary joints 154, and flow paths 156 for each grinding station 100. However, the multi - station grinding system 101 may have a pressure system 150 that has a single pneumatic assembly 152 for all grinding stations 100.

[0031] The compartments 134a, 134b, 134c are pressurized by a pressure system 150, such as with CDA, so that the membrane 132 applies a downward force on the non-acting (back) surface of the substrate 122 as the substrate carrier 110 rotates, to push the substrate 122 against the polishing pad 106. The compartments 134a, 134b, 134c facilitate adjusting the distribution of the force applied across the back surface of the substrate 122 by allowing a pressure differential therein. Before and after polishing, a vacuum is applied to the compartments 134a, 134b, 134c by a pneumatic assembly 152 so that the membrane 132 deflects upward to create a low-pressure pocket between the membrane 132 and the substrate 122, thereby vacuum-adsorbing the substrate 122 to the substrate carrier 110. The vacuum can be applied by reducing the pressure of the CDA in the compartments 134a, 134b, 134c with a vacuum pump (not shown) of the pneumatic assembly 152.

[0032] Failure of the membrane 132, such as a hole or tear, compromises the pressure integrity of the membrane 132. The failed membrane 132 can no longer be pressurized as needed during the polishing process, which may result in insufficient, non-uniform polishing or may damage the substrate 122. Additionally, the pressure loss of the membrane 132 may cause the substrate 122 to slip out of engagement with the membrane 132 during polishing, which may damage the substrate 122. Further, the damaged membrane 132 impedes the ability of the pneumatic assembly 152 to apply a vacuum. The damaged membrane 132 may be unable to vacuum-adsorb the substrate 122 to the substrate carrier head 128. Thus, the failed membrane 132 may prevent the substrate 122 from being removed from the polishing pad 106 together with the substrate carrier 110. The failed membrane may also cause the substrate 122 to be inadvertently dropped by the substrate carrier head 128, such as dropping the substrate 122 when the substrate 122 is transferred from the polishing station 100 to the substrate loading station 103 or from one polishing station 100 to another polishing station 100. If the substrate 122 is dropped by the substrate carrier head 128, the substrate 122 may be damaged.

[0033] Failure of the membrane 132 allows fluid such as the abrasive fluid to undesirably enter the pressure system 150. The entry of fluid such as the abrasive fluid may physically damage and / or block the pressure system 150. For example, the entry of fluid into the pneumatic component 152 may cause damage to the pump (e.g., a vacuum pump). The abrasive fluid may accumulate within the flow path 156, which may clog or block the flow path 156. For example, the abrasive fluid may coat the flow path 156 with a thickness that restricts fluid flow. Due to the restricted fluid communication, the pressure system 150 may not be able to apply the desired pressure to the compartment 134 to create the desired force distribution on the substrate 122. The abrasive fluid may coat the inner surface of the membrane 132, which may reduce the flexibility of the membrane and impair the ability of the membrane 132 to effectively abrade the substrate 122. The entry of fluid into the pressure system 150 may cause the grinding operation to stop immediately. The entry of the fluid results in a significant amount of downtime to open, purge, clean, replace, and / or repair the pressure system 150. Additionally, acids may be used in the abrasive fluid. In addition to physical damage, the entry of fluid through the breached membrane 132 may also chemically corrode the pressure system 150.

[0034] The grinding station 100 may include one or more sensors, such as sensors 160a-c, to monitor the integrity of the membrane 132. The sensors 160a-c may be optical sensors. When the pressure system 150 applies a vacuum to the membrane 132, the sensors 160a-c monitor the integrity of the membrane by sensing the presence of fluid such as the abrasive fluid. The grinding station 100 may include: a first sensor 160a for monitoring fluid entering the first flow path 156a through the first compartment 134a; a second sensor 160b for monitoring fluid entering the second flow path 156b through the second compartment 134b; and a third sensor for monitoring fluid entering the third flow path 156c through the third compartment 134c. The operation of the sensors 160a-c will be described in more detail below with reference to Figures 2A - 2H and Figures 3A - 3C more specifically.

[0035] Each sensor 160a-c may be attached to the rotary joint 154, as Figure 1A shown. In some embodiments, each sensor 160a-c may be disposed at another location on the grinding station 100 in communication with the pneumatic component 152. For example, each sensor 160a-c may be attached to the corresponding flow path 156a-c. In some embodiments, each sensor 160a-c is part of a coupler that joins portions of the respective flow paths 156a-c together.

[0036] The operation of the multi-station grinding system 101 and / or its respective grinding stations 100 is facilitated by a control system 136. The control system 136 can receive inputs from a temperature sensor 114, a platform torque sensor 116, a carriage torque sensor 118, pressure sensors 119a-c, and sensors 160a-c. The control system 136 can respond to these inputs to change the operating parameters of the multi-station grinding system 101.

[0037] For example, the control system 136 can be used to maintain the pressure in each compartment 134a, 134b, 134c, thereby allowing for fine control of the distribution of the force exerted by the membrane 132 on the substrate 122. The control system 136 can cause the pneumatic assembly 152 to adjust the pressure in compartments 134a-c, for example, to regulate the pressure to a target pressure. In some embodiments, the control system 136 can generate a system alarm and / or stop the operation of the grinding station 100 in response to a sensor, such as the first sensor 160a, detecting a fluid (e.g., a grinding fluid).

[0038] The control system 136 can include a programmable central processing unit (CPU) 140 that can operate with a memory 142 (e.g., a non-transitory memory) and support circuitry 144. The support circuitry 144 is coupled to the CPU 140 in a conventional manner and includes a cache, a frequency circuit, an input / output subsystem, a power supply, etc., and their combination is coupled to the various components of the multi-station grinding system 101 to facilitate the control of the substrate grinding process. For example, in some embodiments, the CPU 140 is one of any form of general-purpose computer processor used in an industrial environment, such as a programmable logic controller (PLC), for controlling various grinding system components and sub-processors. The memory 142 is coupled to the CPU 140, and the memory 142 is non-transitory and can be one or more readily accessible memories, such as random access memory (RAM), read-only memory (ROM), disk drives, hard disks, or any other form of digital memory located locally or remotely.

[0039] Here, the memory 142 is in the form of a computer-readable storage medium (e.g., a non-volatile memory) containing instructions that, when executed by the CPU 140, facilitate the operation of the multi-station grinding system 101. The instructions in the memory 142 are in the form of a program product, such as a program (e.g., a middleware application, a device software application, etc.) that implements the methods of the present disclosure. The program code can conform to any of several different programming languages. In one example, the present disclosure can be implemented as a program product stored on a computer-readable storage medium and used with a computer system. The program of the program product defines the functions of the embodiments (including the methods described herein).

[0040] Exemplary computer-readable storage media include (but are not limited to): (1) non-writable storage media (such as read-only memory devices within a computer (such as optical disc media read by an optical drive), flash memory, ROM chips, or any type of solid-state non-volatile semiconductor memory), where information is permanently stored on the non-writable storage media; and (2) writable storage media (such as magnetic disk media or hard disk drives within a disk drive or any type of solid-state random access semiconductor memory), where changeable information is stored on the writable storage media. Such computer-readable storage media are specific embodiments of the present disclosure when loaded with computer-readable instructions that direct the functions of the methods described herein.

[0041] Figures 2A - 2H For showing the first sensor 160a and explaining various optical effects caused by the fluid flowing through the first sensor 160a. Figures 2A - 2C and Figures 2E - 2H The first sensor 160a for monitoring the first flow path 156a is shown. Figures 2A - 2C And 2E - 2H represent the second sensor 160b and the third sensor 160c. Figure 2A An exemplary circuit diagram of the first sensor 160a representing the second and third sensors 160b, c is shown. The sensor 160a includes a light source 200, such as a light-emitting diode (LED) or a laser diode (LD), and a photodiode 202. The light source 200 and the photodiode 202 are positioned at locations on opposite sides of the flow path 156a. The light source 200 emits light 210, and the photodiode 202 is configured to detect the light 210. The light 210 can be emitted at an emission angle 210a, and the light 210 is directed towards the flow path 156.

[0042] A control voltage is fed from a power source to a buffer amplifier 201, and the buffer amplifier 201 drives a current to the light source 200 through a voltage-controlled current source 203. The light output of the light source 200 is determined and controlled by the current flowing through the light source 200 from the voltage-controlled current source 203. The current flowing through the light source 200 is selectively adjusted to produce light within the dynamic range detected by the photodiode 202 during various processing conditions. For example, increasing the current increases the intensity of the light 210. The light 210 detected by the photodiode 202 generates a signal, and the signal is directed to a current-voltage converter 204 and then, in a process opposite to the current fed to the light source 200, is directed to a buffer amplifier 205 to generate an output voltage. The output voltage corresponds to the amount of light 210 detected by the photodiode 202, and the output voltage is received by the control system 136.

[0043] Figure 2AThe cross-section of the first flow path 156a is shown. The flow path 156a may include a pipe 206 having holes 208. The pipe 206 may be a translucent or transparent pipe formed of a chemical-resistant material. For example, the pipe 206 may be a fluoropolymer material, such as a Teflon pipe. The pipe 206 may have an outer diameter, for example, between 5 mm and 10 mm. The light source 200 and the photodiode 202 are disposed on opposite sides of the pipe 206.

[0044] Figures 2B - 2C is a schematic diagram of the first sensor 160a for sensing the fluid in the first flow path 156a to show the lensing effect of the fluid.

[0045] Figure 2B The gas 220, such as nitrogen or dry air, disposed in the hole 208 of the pipe 206 is shown. The gas 220 may be pressurized or in a partial vacuum. For example, the gas 220 may be supplied by the pneumatic assembly 152 to pressurize the first pneumatic device 134a, or the gas 220 may be in a partial vacuum, such as when the pneumatic assembly applies a vacuum to the first compartment 134a. The gas 220 and the pipe 206 have different refractive indices. Figure 2B It is shown that when the first light ray 240 travels through the pipe 206 filled with the gas 220, the exemplary first light ray 240 of the light 210 travels along the first trajectory 242. The first light ray 240 is refracted when passing through the material of the pipe 206 and the gas 220.

[0046] Figure 2C The fluid 230 disposed in the hole 208 in a static steady state is shown, and the fluid 230 has a refractive index different from that of the pipe 206 and the gas 220. The fluid 230 may be an abrasive fluid, such as a slurry or other liquid. When the first light ray 240 travels through the materials of the pipe 206 and the fluid 230, due to refraction, the fluid 230 lenses the first light ray 240 along the second trajectory 244 towards the photodiode 202. As shown, the presence of the fluid 230 causes the second trajectory 244 of the first light ray 240 to move towards the photodiode 202 when leaving the pipe 206 compared to the first trajectory 242. The first trajectory 242 is shown as a dashed line to illustrate the movement caused by the fluid 230.

[0047] The lensing effect of the fluid 230 causes some of the light rays 210 to be detected by the photodiode 202, while these light rays are not detected by the photodiode 202 when the gas 220 is disposed in the pipe 206. The increase in the light 210 detected by the photodiode 202 indicates the presence of the fluid in the first flow path 156a.

[0048] Some of the light 210 is absorbed by the fluid 230. For example, the light 210 passing through the fluid 230 can be converted into heat energy. Some fluids 230 have components with high absorbance, which reduces the amount of light 210 reaching the photodiode 202. For example, opaque fluids, such as certain abrasive fluids with a relatively high concentration of abrasive particles, such as abrasive fluids used for polishing a silicon oxide material layer, can have high absorbance. The absorption of light 210 by the fluid 230 can counteract the lensing effect. In some cases, the absorption of the fluid 230 may cause the control system 136 to fail to recognize that the fluid 230 has replaced the gas 220 in the first flow path 156a. The fluid 230 can have an absorbance such that the amount of light 210 detected by the photodiode 202 is substantially similar to the amount of light detected by the photodiode 202 when the gas 220 (e.g., dry air) present in the flow path 156a is set. For example, due to the absorbance of the fluid 230, the amount of light 210 detected by the photodiode 202 may not exceed the threshold for detecting the presence of the fluid 230.

[0049] Figure 2D The output of the photodiode 202 when detecting the light 210 from the light source 200 is shown to illustrate the lensing effect and absorption effect of various mixtures of oxide slurry and water. The X-axis shows the control voltage supplied to the sensor 160a to generate the light 210. The Y-axis shows the output voltage of the sensor 160a corresponding to the light 210 detected by the photodiode 202 from the light source 200, including the light 210 passing through the flow path 156a.

[0050] The first curve 251 shows the output voltage when dry air is provided in the hole 208. The first curve 251 is a baseline showing the lensing effect and absorption effect of various components of the white oxide slurry compared to dry air. The second curve 252 shows the output voltage when 100% white oxide slurry is arranged in the hole 208. The third curve 253 shows the output voltage when 80% white oxide slurry is provided in the hole 208. The fourth curve 254 shows the output voltage when 60% white oxide slurry is provided in the hole 208. The fifth curve 255 shows the output voltage when 50% white oxide slurry is provided in the hole 208. The sixth curve 256 shows the output voltage when 40% white oxide slurry is provided in the hole 208. The seventh curve 257 shows the output voltage when 20% white oxide slurry is provided in the hole 208. The percentage of the white oxide slurry represents the percentage of the mixture of the white oxide slurry and the additional water. For example, 80% white oxide slurry is a mixture of 20% water and 80% white oxide slurry.

[0051] The sixth curve 256 and the seventh curve 257 show that the lensing of the fluid mixture increases the amount of light received by the photodiode 202, despite the absorbance of the mixture. The sixth curve 256 and the seventh curve 257 show that the sensor 160a produces a higher voltage output than the first curve 251 at certain control voltages. For example, for a 20% white oxide slurry, the sensor 160a outputs a higher voltage than dry air, and its control voltage is between approximately 1.5 V and approximately 4 V supplied to the sensor 160a, as shown by the seventh curve 257. However, due to the saturation of the incident light 210, the output voltages of the first curve 251, the sixth curve 256, and the seventh curve 257 can be substantially similar at certain control voltages (e.g., control voltages between 4 V and 5 V). Therefore, the light 210 can have an intensity that overwhelms the lensing effect and enables the photodiode 202 to detect a similar amount of light, despite the different materials disposed in the tube 206. Thus, the control voltage has a dynamic operating range for detecting the presence of a fluid (e.g., a slurry fluid) from a baseline of a dry gas (e.g., air or nitrogen). For example, the dynamic operating range can be a control voltage between 1.5 V and 4 V. For example, the optimal range for the best distinction between the baseline dry gas and the fluid can be an output voltage between 2.5 V and 3.0 V.

[0052] As shown by the second curve 252, the 100% white oxide slurry has high absorbance and reduces the amount of light detected by the photodiode 202 compared to the amount of light detected if dry air were disposed in the tube 206. As the concentration of the white oxide slurry decreases, the absorbance of the slurry mixture decreases. The decrease in absorbance is reflected in Figure 2D which Figure 2D illustrates that the output voltage increases as the concentration of the white oxide slurry decreases. For example, when the control voltage supplied to the light source 200 is between 2 V and 5 V, the output of the photodiode 202 for an 80% white oxide slurry is greater than that for a 100% white oxide slurry. For example, when the control voltage supplied to the light source 200 is between 2 V and 5 V, for a 60% white oxide slurry, the output of the photodiode 202 is greater than the output of the photodiode 202 for an 80% white oxide slurry.

[0053] The photodiode 202 can output data (e.g., output voltage) with sufficient signal-to-noise ratio to detect some fluid components flowing through the tube 206 at some voltages of the light source 200 by direct comparison with the baseline first curve 251. For example, the control system 136 is capable of distinguishing between dry air and a 100% white slurry at a control voltage of approximately 4 V supplied to the light source 200, for example, by comparing the output with a threshold.

[0054] However, for all components of the fluid 230 at a particular intensity of the light source 200, the output of the photodiode 202 may not have a signal-to-noise ratio sufficient to distinguish the fluid from a gas (such as dry air). There may be some concentrations of the white slurry that result in an output similar to that of the gas, such as the dry air shown in the first curve 251. For example, some concentrations of the white slurry may produce a curve similar to the first curve 251, such that the control system 136 cannot distinguish the slurry from the dry air. And, as Figure 2D shown, some control voltages of the light source 200 cause the photodiode 202 to output data of the slurry mixture that is substantially similar to the output in the presence of dry air. For example, the output voltages of the first curve 251, the sixth curve 256, and the seventh curve 257 may be substantially similar at certain control voltages of the light source 200 (such as control voltages between 4V and 5V).

[0055] For example, the first curve 251 is sandwiched between the fifth curve 255 and the sixth curve 256 corresponding to white oxide slurry concentrations of 50% and 40%, respectively. It should be expected that even if the control voltage is in the optimal range, a particular concentration of the white slurry between 50% and 40% may produce a curve similar to the first curve 251, such that the control system 136 cannot distinguish the slurry from the dry air. Therefore, comparing the output voltage with the baseline curve 251 may not be suitable for detecting the presence of the fluid in all cases.

[0056] In addition, the components of the fluid 230 passing through the first sensor 160a may be unknown. For example, the fluid 230 may have proprietary components unknown to the control system 136. By directly comparing the sensor output with a baseline (such as the baseline first curve 251 of dry air), or by comparing the sensor output with a threshold based on the baseline, it may not be possible to satisfactorily detect the proprietary components. In addition, the unknown fluid 230 may have components that the sensor cannot distinguish from a gas (such as dry air or nitrogen) at a particular intensity of the light source 200.

[0057] When the fluid 230 enters the conduit 206 due to the vacuum applied by the pneumatic assembly 152, there may be an initial burst of turbulence of the fluid flowing through the sensor 160. This initial burst of turbulence may include one or more bubbles of the gas 220 disposed in the fluid 230. The bubbles define an interface between one or more fluids and air. In some embodiments, the fluid 230 passing through the first sensor 160a may be one or more droplets that do not completely fill the holes 208, and the droplets may define one or more fluid-air interfaces. Figures 2E - 2H Total internal reflection (TIR) caused by the fluid-gas interface is shown. As will be explained, total internal reflection affects the output of the first sensor 160a and can be used to identify the presence of the fluid regardless of the composition of the fluid.

[0058] Figure 2E is similar to Figure 2B because gas 220 is disposed in the hole 208. As Figure 2E and 2F shown, a second light ray 260 of the light 210 is emitted from the light source 200 at a normal angle of incidence. When the second light ray 260 passes through the material of the conduit 206 and the gas 220, the second light ray 260 is shown to follow a first trajectory 262. The first trajectory 262 guides the second light ray 260 towards the photodiode 202. Figure 2F A fluid 230 that partially fills the tube 206 is shown such that a bubble 220 is disposed in the hole 208. An interface 232 between the first fluid of the fluid 230 and air of the bubble 220 is shown at an angle with respect to the second light ray 260. The interface 232 between the first fluid and air may be at an angle sufficient to cause total internal reflection of the second light ray 260, which redirects the second light ray 260 back into the fluid 230. A second trajectory 264 shows the path of the second light ray 260 when totally reflected by the interface 232 between the first fluid and the gas. Total internal reflection of the second light ray 260 along the second trajectory 264 guides the second light ray 260 away from the photodiode 202, which prevents the second light ray 260 from being detected. The first trajectory 262 is shown as a dashed line in Figure 2F to better show the change in the trajectory of the second light ray 260 caused by the interface 232 between the first fluid and air. Total internal reflection caused by the interface between the fluid and air may cause the light 210 not to be detected by the photodiode 202, which would otherwise detect the light 210 in the presence of only the gas 220. Thus, total internal reflection can reduce the amount of light 210 detected by the photodiode 202.

[0059] Figure 2G is similar to Figure 2B because gas 220 is disposed in the hole 208. As Figure 2G and 2H shown, a third light ray 270 of the light 210 is emitted from the light source 200. When the third light ray 270 passes through the material of the conduit 206 and the gas 220, the third light ray 270 is shown to follow a first trajectory 272. As shown by the first trajectory 272, the third light ray 270 is not guided towards the photodiode 202 and thus is not detected by the photodiode 202. Figure 2HThe fluid 230 that partially fills the tube 206 is shown such that air bubbles 220 are disposed in the holes 208, which results in a second fluid-air interface 234. The second fluid-air interface 234 can be at an angle sufficient to cause total internal reflection of a third light ray 270. The second trajectory 274 shows the path of the third light ray 270 after being totally reflected by the second fluid-gas interface 234. The TIR of the third light ray 270 along the second trajectory 274 guides the third light ray 270 towards the photodiode 202. The first trajectory 272 is shown as a dashed line in Figure 2H to better show the change in the trajectory of the third light ray 270 caused by the second fluid-air interface 234. Total internal reflection can cause the light 210 to be detected by the photodiode 202, which would otherwise not be detected if only the gas 220 were present. Thus, total internal reflection can increase the amount of light 210 detected by the photodiode 202.

[0060] Fluid-gas interfaces such as interfaces 232, 234 can cause distinct spikes in the output of the photodiode, which are caused by an increase or decrease in the amount of light detected due to total internal reflection. The angle and number of fluid-gas interfaces flowing past the first sensor 160a can fluctuate as the fluid passes through. When the amount of detected light 210 fluctuates, this change is reflected in the output of the first sensor 160a.

[0061] Figure 3A The output 300 (e.g., output voltage) of the photodiode 202 of the first sensor 160a in response to the light 210 emitted from the light source 200 is shown, which represents the outputs of the photodiodes of the second sensor 160b and the third sensor 160c. The sensor output 300 can be further processed by an analog electronic circuit such as an amplifier, and the circuit output can be measured and displayed by an oscilloscope. As Figure 3A shown, the output 300 of the photodiode 202 (shown in volts on the Y-axis) fluctuates with time (shown in seconds on the X-axis). In the first region 301 of the output 300, the gas of the pressure system 150 flows through the sensor 160. In the region 302 of the output 300, the turbulent fluid initially flows through the sensor 160, and the turbulent fluid is a 60% white oxide slurry mixed with air bubbles. In the third region 303 of the output 300, a steady flow of the 60% white oxide slurry flows smoothly through the first sensor 160a with few or no air bubbles.

[0062] The second region 302 of the output 300 includes spikes with a greater amplitude than the other regions 301, 303 of the output 300. The second region 302 includes lens effects, absorption effects, and total internal refraction effects. The second region 302 is a signal where fluid is present, and the first region 301 and / or the second region 303 are background noise. As Figure 3AAs shown, the signal-to-noise ratio of the second region 302 is approximately 2 compared to the other two regions 301 and 303. The signal-to-noise ratio can be measured as the difference between the maximum and minimum outputs detected in the second region 302 divided by the difference between the maximum and minimum outputs detected in the output 300 of region 301.

[0063] To enhance the signal-to-noise ratio, the output 300 can be processed by the control system 136. For example, the CPU 140 can process the output 300 to generate Figure 3B the processed output 300a shown in. In some embodiments, the output 300 of the first sensor 160a being processed can be raw data, such as raw data from a circuit. In some embodiments, the output 300 of the raw circuit data is exported to a data analysis program, such as Microsoft Excel, before being processed. The processed output 300a includes a first processed region 301a corresponding to the first region 301, a second processed region 302a corresponding to the second region 302, and a third processed region 303a corresponding to the third region 303. As shown, compared to the original (e.g., unprocessed) output 300, the difference between the second processed region 302a and the first processed region 301a and the third processed region 302a is more obvious. As Figure 3B shown, the signal-to-noise ratio is approximately 16.

[0064] The output 300 can be processed by Figure 3C the algorithm 310 shown to generate the processed output 300a. Figure 3B The processed output 300a shown in is the square of the standard deviation (denoted as σ 2 ), also known as the variance. The processed output 300a can be plotted as the variance (Y-axis) over time (X-axis), as Figure 3B shown. The variable V k is the output voltage of the photodiode 202 and the summation index k, where k = i, i + 1, …, i + N. The index i represents the i-th time point. The variable a is the average value. N is the number of samples selected around each time point i, and N is a smoothing factor. For example, N can be a value between 3 and 10, including 3 and 10.

[0065] Figure 3B The processed output 300a shown in is generated by processing the output 300 with the algorithm 310. The value of N is set to 4, and the average value a of the output 300a is 2.5V.

[0066] A control system 136 such as the CPU 140 can monitor the processed output 300a to determine if it exceeds a threshold 320. The threshold 320 can be a value of the variance, such as Figure 3BThe value 3 shown in [figure]. The threshold 320 can be selected based on the fluid 230 (e.g., the grinding slurry). For example, the threshold 320 can be selected based on a 50% oxide slurry concentration, which is a 50% oxide slurry mixed with 50% deionized water. The threshold 320 based on the variance of the output 300 reduces the cases of false alarms or missed detections of the fluid using the first sensor 160a because the signal-to-noise ratio is enhanced compared to the original output 300. The threshold 320 can be set based on the maximum expected value associated with the sensor that detects the turbulent fluid 230 processed by the algorithm 310. The threshold 320 can be set with an additional margin or safety factor, such as a value that is approximately 50% to 100% greater than the maximum value detected in the first region 301a or the third region 303a. In some embodiments, the threshold 320 can be selected based on the gas used by the pneumatic component 152. For example, the threshold 320 can be selected based on the expected variance value of dry air or nitrogen, such as the expected variance of the gas over a similar duration.

[0067] In some embodiments, the signal-to-noise ratio of the output of the photodiode 202 (e.g., the output 300) can be increased from approximately 2 to approximately 9 by processing the output with the algorithm 310. In some embodiments, by processing the output with the algorithm 310, the signal-to-noise ratio is increased from approximately 2 to approximately 10. In some embodiments, by processing the output with the algorithm 310, the signal-to-noise ratio can be increased from approximately 2 to approximately 24.

[0068] Comparing the processed output with the threshold helps detect the initial burst of the fluid, regardless of the composition of the fluid. Additionally, comparing the processed output 300a with the threshold 320 allows the detection of the initial burst of the fluid, even if the composition of the fluid used in the multi-station grinding system 101 is unknown to the control system 136 and / or the sensor 160.

[0069] In some cases, the fluid passing through the sensor (e.g., the first sensor 160a) may initially include or define one or more fluid-air interfaces before transitioning to a steady-state flow without one or more fluid-air interfaces (e.g., laminar flow). The control system 136 can detect the initial burst of the fluid by comparing the processed output with the threshold, regardless of how fast or slow the fluid transitions to a steady-state flow without one or more fluid-air interfaces.

[0070] For some compositions of the fluid used in the multi-station grinding system 101, sensors such as the first sensor 160a can detect the presence of a steady-state flow of the fluid 230 without one or more fluid-air interfaces and distinguish the fluid 230 from a baseline (e.g., the first curve 251), such as Figure 2C in the case where the fluid 230 shown fills the hole 208 of the tube 206.

[0071] The control system 136 can monitor the failure of the membrane 132 without processing the sensor output through an algorithm (such as algorithm 310) and comparing the sensor output with a threshold. However, the signal-to-noise ratio of the output is less than that of the output processed by an algorithm such as algorithm 310. Due to the lower signal-to-noise ratio, it is more likely to have false alarms and missed detections when comparing the unprocessed sensor output with a threshold (such as a sensor output value). For example, based on the composition of the liquid, the unprocessed outputs of the gas and the liquid may be similar, and the threshold may be set to a value that cannot record the presence of the liquid.

[0072] The control system 136 can monitor the failure of the membrane 132 over a period of time (such as a test period). A vacuum can be applied to the membrane 132 by the pressure system 150 during the test period. If fluid is detected in the pressure system 150 during the test period, the control system 136 can generate an alarm that the membrane 132 has failed and / or the pressure system 150 can stop the operation of the grinding station 100. If no fluid is detected during the test period, the control system 136 can continue with operations, such as a grinding operation or an operation to move the substrate 122.

[0073] Figure 4 An exemplary method 400 for detecting a failed membrane 132 using a sensor such as the first sensor 160a is shown. As shown at 401, the pressure system 150 applies a vacuum to the membrane 132. The vacuum can be applied over a period of time, such as a test period. The test period can be a few seconds, such as ten seconds, or a few minutes, such as two minutes. If the membrane 132 fails, such as tears, fluid can enter the pressure system 150. A sensor such as the first sensor 160a monitors the fluid while the vacuum is being applied. At block 402, the sensor generates an output, such as data. The sensor output can be transmitted to the control system 136, such as the CPU 140. At block 403, the output of the sensor is processed to produce a processed output. The sensor output is processed to enhance the signal-to-noise ratio of the output, such as by processing the sensor output with algorithm 310. The sensor output can be processed by the control system 136, such as by the CPU 140. At block 404, the processed output is compared with a threshold. The control system 136, such as the CPU 140, can compare the processed output with the threshold to determine if the threshold is exceeded. If the processed output exceeds the threshold, the sensor has detected fluid. If the sensor 160 has detected fluid, the membrane 132 has failed. In some embodiments, the control system 136 can stop the operation of the control station 100 or the multi-station grinding system 101, as shown at block 405. In some embodiments, the control system 136 can generate an alarm regarding the membrane failure, and the user can initiate the shutdown of the control station 100 or the multi-station grinding system 101.

[0074] Figure 5 An exemplary method 500 for showing the integrity of the test membrane 132 is shown. The integrity of the membrane 132 can be tested before moving the substrate 122, grinding the substrate 122, or vacuum - adsorbing the substrate 122 to the membrane 132. As shown at 501, instructions are sent to the pressure system 150 to apply a vacuum to the membrane 132. For example, before the operation of moving the substrate 122 from the loading station 103 or moving the substrate from the grinding pad 106, the pressure system 150 can be instructed to apply a vacuum to the membrane 132. The vacuum can be applied during a test period. During the test, the substrate 122 can be vacuum - adsorbed to the membrane 132.

[0075] As shown in block 502, the control system 136 monitors the failure of the membrane 132 by processing the output of a sensor (such as the first sensor 160a) to produce a processed output. In block 503, the control system 136 determines whether the membrane 132 has failed by comparing the processed output with a threshold. If the threshold is exceeded, a failure is detected.

[0076] If no failure is detected, the control system 136 continues to control the normal operation of the station 100 and / or the multi - station grinding system 101, as shown in block 504, for example, continuing to move the substrate 122 from the loading station 103 to the grinding pad 106. In some embodiments, if no failure of the membrane 132 is detected, the control system 136 instructs the pressure system 150 to apply a vacuum to the membrane 132 to vacuum - adsorb the substrate 122 to the membrane. In some embodiments, if no failure of the membrane 132 is detected, the pressure system 150 applies pressure to the membrane to push the substrate 122 against the grinding pad 106. In some embodiments, if no failure is detected, the control system 136 instructs the substrate transfer carriage 115 to move the substrate 122 from the loading station 103 to the grinding pad 106, or to move the substrate 122 from the grinding pad 106.

[0077] If a failure is detected, the control system 136 generates an alarm to notify the user of the membrane failure, as shown in block 505. If the failure of the membrane 132 is detected, the control system 136 can stop the operation of the station 100 or the multi - station grinding system 101. If a failure is detected, the membrane 132 is replaced, as shown in block 506. The pressure system 150 can also be cleaned before or during the replacement of the membrane 132. The method 500 can be repeated after the replacement of the membrane 132 until no failure is detected.

[0078] In some embodiments, the user interface of the multi - station grinding system 101 displays the sensor output and / or the processed sensor output. The user can selectively change the threshold, for example, when changing the slurry fluid used in the grinding station 100 or the gas used by the pressure system 150.

[0079] Each of the sensors 160a-c can be housed or otherwise shielded to reduce the exposure of the sensors to ambient light, e.g., shielding the light source 200 and the photodiode 202 from ambient light. In some embodiments, the sensor housing includes a material that absorbs light not detected by the sensor to prevent light from reflecting within the housing and entering the photodiode 202. Reducing ambient light and reducing light reflection entering the sensor can reduce the noise in the sensor output.

[0080] In some embodiments, sensors such as a first sensor 160a, a second sensor 160b, and a third sensor 160c can be included in a sensor assembly. The sensor assembly can have a housing with ports to connect to the flow paths 156a-c. The sensors can be attached to the rotary joint 154 by attaching the sensor assembly to the rotary joint 154.

[0081] In some embodiments, a fluid is detected by comparing the output of the sensor to a baseline value (e.g., the expected output of dry air at a given light intensity). If the difference between the sensor output and the baseline exceeds a threshold, e.g., the sensor output is more than 1V above or below the baseline, the control system 136 can detect the fluid.

[0082] In some embodiments of the grinding station 100, the membrane 132 has one compartment. One sensor monitors whether the grinding fluid enters the one compartment. In some embodiments of the grinding station 100, the membrane 132 includes two or more compartments. Each compartment is monitored by a corresponding sensor to detect failure of the membrane 132.

[0083] In one embodiment, a grinding system includes a pressure system, a substrate carrier including a membrane, sensors, and a control system. The membrane is fluidly coupled to the pressure system, and the pressure system is configured to control the flow rate and pressure of gas to the membrane. The sensors are configured to monitor the pressure system and generate an output based on the conditions detected in the pressure system. The control system is coupled to the pressure system and the sensors and is configured to process the output to generate a processed output. The control system is configured to compare the processed output to a threshold to detect the presence of fluid in the pressure system.

[0084] In some embodiments of the grinding system, the processed output is the change in the output over time. In some embodiments, the threshold is based on a variance threshold of the fluid. In some embodiments, the fluid is a grinding slurry. In some embodiments, the threshold is based on a variance threshold of the gas in the pressure system.

[0085] In some embodiments of the grinding system, the sensor includes a light source configured to emit light and a photodiode configured to detect light.

[0086] In some specific embodiments of the grinding system, a sensor is attached to a rotary joint, and the rotary joint is coupled to a substrate carrier.

[0087] In some specific embodiments of the grinding system, a membrane defines a plurality of compartments in communication with a pressure system. The sensor includes a plurality of sensors, each of the plurality of sensors monitoring a separate flow path of the pressure system, each flow path being in fluid communication with a corresponding one of the plurality of compartments. The control system is configured to process the output of each sensor to produce a processed output of each sensor and compare the processed output of each sensor with a threshold to detect the presence of fluid.

[0088] In some specific embodiments of the grinding system, the control system includes a computer-readable medium storing instructions for a membrane integrity method. The stored membrane integrity method includes: (a) instructing the pressure system to apply a vacuum to the membrane; (b) processing the output while the pressure system applies the vacuum to produce a processed output; (c) comparing the processed output with a threshold; (d) determining that the membrane has failed if the processed output exceeds the threshold. In some specific embodiments of the grinding system, the method further includes generating an alert for the user identifying the membrane failure when the control system determines that the membrane has failed.

[0089] In some specific embodiments of the grinding system, when the fluid passing through the sensor includes at least one fluid-gas interface, it exceeds the threshold.

[0090] While the foregoing relates to specific embodiments of the present disclosure, other and further specific embodiments may be devised without departing from the basic scope of the foregoing, and the scope of the foregoing is determined by the following claims.

Claims

1. A grinding system, comprising: Pressure system; a substrate carrier comprising a membrane, wherein a first compartment of the membrane is fluidly coupled to the pressure system; a first sensor configured to monitor the pressure system and generate a first output based on a condition detected in the pressure system; and A control system is coupled to the first sensor and configured to process the first output to produce a first processed output, the control system configured to compare the first processed output to a threshold value to detect the presence of fluid in the pressure system.

2. The grinding system of claim 1, wherein the first process output is a variance of the first output over time, wherein the threshold is a variance threshold based on the fluid.

3. The polishing system of claim 1, wherein the first sensor is attached to a rotary joint coupled to the substrate carrier.

4. The grinding system according to claim 1, in: The pressure system includes a first tube fluidly coupled to the first compartment; The first sensor includes a first light source and a first photodiode, the first light source irradiates a first light to the first tube, and the first photodiode is located on the other side of the first tube and the first light source to detect the first light; and The first sensor generates the first output based on an amount of the first light detected by the first photodiode.

5. The grinding system according to claim 4, in: The membrane includes a second compartment; The pressure system includes a second tube fluidly coupled to the second tube; The system includes a second sensor configured to monitor the second tube; The second sensor includes a second light source and a second photodiode, the second light source irradiates a second light to the second tube, and the second photodiode is located on the other side of the second tube away from the second light source to detect the second light; the sensor generating a second output based on an amount of the second light detected by the second photodiode; and The control system is coupled to the second sensor and is configured to process the second output to produce a second processed output, the control system being configured to compare the second processed output to the threshold to detect the presence of the fluid in the second tube.

6. The grinding system of claim 1, the control system comprising a computer readable medium having stored thereon instructions for a film integrity method, the method include: (a) directing a pressure system to apply a vacuum to the first compartment of the membrane; (b) processing the output while the pressure system applies the vacuum to produce the first processed output; (c) comparing the first processed output with the threshold; and (d) if the first process output exceeds the threshold, determining that the membrane has failed.

7. The grinding system of claim 6, wherein the method further comprises: include: When the control system determines that the membrane has failed, an alert is generated for a user identifying the failure of the membrane.

8. The grinding system of claim 1, wherein the threshold has been exceeded when the fluid passing through the first sensor includes at least one fluid and gas interface.

9. A non-transitory computer readable medium storing instructions that when executed by one or more processors cause a lapping system to perform an integrity test on a film positioned in a carrier head, the integrity test comprising: Applying a vacuum to the membrane using a pressure system for a period of time; processing an output of a sensor monitoring the pressure system over the period of time to produce a processed output; and The processed output is compared to a threshold value to monitor the presence of liquid in the pressure system.

10. The medium of claim 9, wherein the threshold is a variance threshold based on a gas of the pressure system.

11. The medium of claim 9, wherein the integrity test further comprises: include: Failure of the membrane is detected when the process output exceeds the threshold.

12. The medium of claim 11, said integrity testing further comprising generating an alarm identifying said failure of said membrane when said failure is detected.

13. The medium of claim 11, wherein the threshold is exceeded when the fluid passing through the sensor includes at least one fluid and gas interface.

14. The medium of claim 9, wherein the integrity test further include: After determining that no fluid is present in the pressure system during the period of time, the one or more processors cause the grinding system to perform operations including: applying a vacuum to the film to vacuum-adsorb the substrate onto the film; and A substrate processing carriage is moved to move the substrate from the loading station to the polishing pad, wherein the carrier head is coupled to the substrate processing carriage.

15. The medium of claim 9, wherein the integrity test further include: After determining that no fluid is present in the pressure system for the period of time, the one or more processors cause the polishing system to perform operations including applying pressure to the membrane to push the surface of the substrate against the polishing pad.

16. A method of operating a grinding system, the method include: operating a carrier head including a membrane engageable with a substrate, wherein an internal pressure of the membrane is selectively varied by a pressure system; monitoring the membrane for failure during the operation using a sensor, wherein the monitoring comprises: processing an output of the sensor to produce a processed output, and comparing the processed output to a threshold value based on a gas in the pressure system; and The user is alerted that the membrane has failed.

17. The method of claim 16, wherein the operation is testing the integrity of the film prior to grinding the substrate.

18. The method of claim 17, further comprising: An absence of fluid in the pressure system is determined for the period of time.

19. The medium of claim 18, further comprising: include: After determining that no fluid is present in the pressure system, applying a vacuum to the membrane to vacuum the substrate to the membrane; and A substrate processing carriage is instructed to move the substrate from the loading station to the polishing pad, wherein the carrier head is coupled to the substrate processing carriage.

20. The method of claim 18, wherein the threshold is exceeded when the fluid passing through the sensor includes at least one fluid and gas interface.

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