Method for detecting liquid leakage of grinding cavity and automatically recycling wafer

Abstract

The invention provides a grinding cavity liquid leakage detection and wafer automatic recovery method, which comprises the following steps of: 1, performing signal triggering after detecting liquid leakage of a grinding cavity by adopting a liquid leakage detection device of a resistance-capacitance dual-mode cooperative working mechanism so as to start an emergency event processing program; 2, activating a machine alarm system, and reminding an on-duty engineer to carry out fault processing; 3, stopping the supply of the grinding liquid, and stopping the grinding of the grinding cavity; 4, recycling the wafer through an automatic wafer recycling system; and 5, self-checking and resetting the system. When a protective layer outside the air cylinder is damaged and liquid enters the liquid leakage detection device, the liquid leakage detection device is triggered to remind an on-duty engineer to carry out fault processing through a machine alarm system and automatically recycle wafers in the machine in the first time, so that wafer scrapping caused by change of a specific environment when a grinding cavity loses the sealing performance for grinding is avoided; and serious safety incidents caused by liquid leakage of the grinding cavity are also avoided.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and particularly to a method for detecting liquid leakage in a grinding chamber and automatically recycling wafers. Background Art

[0002] During the monitoring and processing of wafers by existing Chemical Mechanical Polishing (CMP) machines, due to the differences in the front and back end processes and the types of polishing liquids used on each polishing pad, the cylinder drives the platen shield to move up and down through the inlet pipe (the yellow plastic pipe in Figure 1 and the outlet pipe (the white plastic pipe) to block the polishing liquid on each polishing pad. When the cylinder moves up and down smoothly, the sensor is triggered. However, since the external protective layer (bellows) of the cylinder is in different environments of acidic and alkaline polishing liquids in the front and back ends of CMP, and considering the working characteristics of the bellows which often expand and contract, the bellows are often corroded and damaged by the acidic and alkaline polishing liquids. The liquid in the grinding chamber will flow out of the machine through the wire holes (the holes through which the inlet pipe, the outlet pipe, and the wires of the cylinder lifting sensor enter and exit). Moreover, during the structural design of the machine, it is not considered how the most liquid-leakage-prone places in the grinding chamber can be detected by engineers in a timely manner and corresponding measures can be taken, as well as the following safety hazards when the wafers in the machine continue to operate after the liquid leakage in the grinding chamber: First, due to the damage of the bellows, the grinding chamber loses its original specific environment provided for the wafers being polished, and particles in the air may enter the grinding chamber, posing risks of defects or scrapping to the wafers; Second, the original polishing liquid and deionized water (mostly polishing liquid) in the grinding chamber flow out of the machine, causing pollution to the entire operating environment due to the special chemical properties of the polishing liquid and also causing harm to the health of the staff. Summary of the Invention

[0003] In view of the above-mentioned disadvantages of the prior art, the purpose of this application is to provide a method for detecting liquid leakage in a grinding chamber and automatically recycling wafers, which is used to solve the problem that it is difficult to detect liquid leakage in the grinding chamber in the prior art, resulting in defects or scrapping of wafers.

[0004] To achieve the above-mentioned purpose and other related purposes, this application provides a method for detecting liquid leakage in a grinding chamber and automatically recycling wafers, including:

[0005] Step 1, after the liquid leakage detection device using a resistance-capacitance dual-mode collaborative working mechanism detects liquid leakage in the grinding chamber, it triggers a signal to start an emergency event handling program;

[0006] Step 2, activate the machine alarm system to remind the on-duty engineer to handle the fault;

[0007] Step 3, terminate the supply of the polishing liquid and stop the grinding in the grinding chamber;

[0008] Step 4: Recover the wafers through the wafer automatic recovery system;

[0009] Step 5: System self-check and reset.

[0010] Preferably, under the dual-mode cooperation of resistance and capacitance, the resistance signal can quickly respond to the conductive liquid, the capacitance signal can cover all types of liquids, and the resistance and capacitance measurement circuits are alternately activated to avoid signal interference.

[0011] Preferably, the liquid leakage detection device is a "resistance-capacitance dual-mode sensor" with a cylindrical alternating electrode layout, and there are 4 holes in the middle for the inlet pipe, outlet pipe, and cylinder lifting sensor wires to pass through respectively.

[0012] Preferably, the alternating electrode layout adopts an alternating layout of circular ring grid electrodes, the electrode spacing is 0.5 mm, and the electrodes are plated with a platinum layer or a chromium-nickel layer.

[0013] Preferably, the liquid leakage detection device is connected to the machine alarm system and the wafer automatic recovery system.

[0014] Preferably, in Step 1, when the leakage amount reaches the trigger threshold, the liquid leakage detection device sends a digital signal to the PLC, and after receiving the signal, the PLC starts the emergency event handling program.

[0015] Preferably, the trigger threshold is a leakage amount ≥ 0.5 ml.

[0016] Preferably, in Step 2, the factory MES system is used to send an alarm message to the mobile phone and PC of the on-duty engineer.

[0017] Preferably, in Step 3, after the PLC sends a shutdown instruction to the grinding fluid supply device, the solenoid valve is de-energized, and the system records the liquid supply stop time and the valve status.

[0018] Preferably,

[0019] As described above, the method for detecting liquid leakage in the grinding chamber and automatically recovering wafers provided by the present application has the following beneficial effects: when the outer protective layer (bellows) of the cylinder is damaged and liquid enters the liquid leakage detection device, the liquid leakage detection device is triggered to remind the on-duty engineer to handle the fault through the machine alarm system and automatically recover the wafers in the machine in the first time, avoiding the scrapping of wafers due to the change of the specific environment during grinding caused by the loss of the sealing performance of the grinding chamber, and also avoiding serious safety incidents caused by liquid leakage in the grinding chamber. Description of the Drawings

[0020] To more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0021] Figure 1 Shown is a physical diagram of a cylinder inside an existing grinding machine.

[0022] Figure 2 Shown is a flowchart of the method for detecting liquid leakage in the grinding chamber and automatically recycling wafers provided by the embodiments of the present application.

[0023] Figure 3 Shown is a cross-sectional schematic diagram of the liquid leakage detection device provided by the embodiments of the present application. Specific Embodiments

[0024] The following illustrates the embodiments of the present application through specific examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] The following will clearly and completely describe the technical solutions in the present application in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of them. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0026] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can also be the communication inside two components. It can be a wireless connection or a wired connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0028] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0029] Please refer to Figure 2 , which shows the flowchart of the method for detecting liquid leakage in the grinding chamber and automatically recycling wafers provided by the embodiments of the present application.

[0030] As Figure 2 shown, the method for detecting liquid leakage in the grinding chamber and automatically recycling wafers includes the following steps:

[0031] Step 1: After the liquid leakage detection device using the resistance-capacitance dual-mode collaborative working mechanism detects liquid leakage in the grinding chamber, a signal is triggered to start an emergency event handling program;

[0032] Step 2: Activate the machine alarm system to remind the on-duty engineer to handle the fault;

[0033] Step 3: Terminate the supply of the grinding liquid, and the grinding in the grinding chamber stops;

[0034] Step 4: Recycle the wafers through the wafer automatic recycling system;

[0035] Step 5: System self-check and reset.

[0036] In Step 1, the liquid leakage detection device is a "resistance-capacitance dual-mode sensor" with a cylindrical alternating electrode layout designed according to the diameter of the wire hole in Figure 1 . As Figure 3 shown, the diameter of its cross-section matches the diameter of the wire hole in Figure 1 . And there are 4 holes in the middle of the liquid leakage detection device for the air inlet pipe, air outlet pipe, and the wires of the cylinder lifting sensor to pass through respectively, which is convenient for installation and disassembly. The diameter of the cross-section of the liquid leakage detection device is about 3.5 cm, the diameter of the 2 holes for the air inlet pipe and air outlet pipe to pass through is 0.5 cm, and the diameter of the 2 holes for the wires of the cylinder lifting sensor to pass through is 0.25 cm.

[0037] The alternating electrode layout adopts an alternating layout of circular ring grid electrodes (the resistance sensor and the capacitance sensor are arranged alternately), asFigure 3 As shown, the electrode spacing is 0.5 mm, and the electrodes are plated with a platinum layer or a chromel layer (thickness ≥ 5 μm) to prevent corrosion by the abrasive slurry.

[0038] The working mechanism of the resistance-capacitance dual-mode collaboration is as follows: The resistance signal responds quickly to conductive liquids (within 0.1 second), the capacitance signal covers all liquid types and has high sensitivity; the resistance and capacitance measurement circuits are alternately activated to avoid signal interference.

[0039] The working principle of the liquid leakage detection device: ⑴ Resistance detection mode. When the abrasive slurry in the grinding chamber contacts the electrodes, a conductive path is formed, and the resistance between the electrodes decreases significantly. The change in the resistance value is used to detect whether the abrasive slurry leaks. For non-conductive liquids (such as deionized water in the grinding chamber of a CMP machine), the change in resistance is not sensitive, and the capacitance mode needs to be relied on; ⑵ Capacitance detection mode. When deionized water enters the area between the electrodes, the dielectric constant between the plates will change, resulting in a change in the capacitance value.

[0040] The performance indicators of the liquid leakage detection device are as follows: For the resistance mode in "resistance-capacitance dual-mode collaboration": 0.5 ml / cm 2 and for the capacitance mode: 0.2 ml / cm 2 .

[0041] The liquid leakage detection device is connected to the machine alarm system and the wafer automatic recovery system. When the outer protective layer (bellows) of the cylinder is damaged and the liquid in the grinding chamber infiltrates into the liquid leakage detection device, and the leakage amount reaches the trigger threshold (≥ 0.5 ml), the liquid leakage detection device sends a digital signal to the PLC (programmable logic controller). After receiving the signal, the PLC starts an emergency event handling program.

[0042] In step two, after the alarm system is activated, the following operations are implemented: ⑴ Local alarm, triggering the red warning light of the machine (strobe mode) and starting the buzzer (85 db, continuously sounding until the alarm is eliminated); ⑵ Remote notification: Sending alarm information to the mobile phone / PC of the on-duty engineer through the factory MES system. The alarm information includes: machine number, leakage location, leakage amount, time axis, sensor data, etc., to remind the on-duty engineer to handle the fault.

[0043] In step three, the PLC sends a shutdown instruction to the abrasive slurry supply device (response time < 0.5 s); the solenoid valve of the abrasive slurry pipeline is de-energized (action time ≤ 30 ms), cutting off the supply of the abrasive slurry, and the grinding in the grinding chamber stops; the system records the liquid supply stop time and the valve status.

[0044] In step four, the automatic wafer recovery system transfers the wafer to the wafer outgoing position by suction, and the Wet Robot transfers the wafer to the cleaning chamber for cleaning and final drying. Then the FI Robot sends the dried wafer to the inspection equipment. If any abnormality is found (such as uneven film thickness), the wafer will be marked and isolated, and the qualified wafer will be sent to the wafer box to complete the wafer recovery action to avoid the wafer staying in the machine for a long time and causing oxidation and scrap.

[0045] The wafer automatic recycling system automatically recycles wafers through the joint control of the hardware layer and the software layer. Hardware layer: The PS side runs Linux, and the PL side realizes real-time processing of sensor signals; Software layer: The running logic code:

[0046] enum RecoveryState{IDLE,LEAK_DETECTED,ARM_ACTIVE,WAFER_SAVED};

[0047] if(dual_sensor_trigger&&cross_validation()){

[0048] set_state(LEAK_DETECTED);

[0049] activate_emergency_stop();

[0050] if (arm_status == READY) {

[0051] set_state(ARM_ACTIVE);

[0052] execute_trajectory_planning();

[0053] transfer_to_emergency_pod();

[0054] set_state(WAFER_SAVED);

[0055] }

[0056] }

[0057] In step five, after the on-duty engineer handles the leakage in the grinding chamber, the PLC performs status verification of the leakage detection device and confirmation of the closure of the electromagnetic valve in the grinding liquid pipeline. After that, the on-duty engineer manually enters the authorization password and accesses the machine alarm status.

[0058] During the above process, the false alarm rate ≤ 0.1 times per thousand hours; the success rate of wafer recovery: ≥ 99.99%; the full response time of the system ≤ 1.5 seconds (from detecting the closing of the carrier).

[0059] It should be noted that the illustrations provided in this embodiment only schematically illustrate the basic concept of the present application. Therefore, only the components related to the present invention are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0060] In summary, for the method of detecting liquid leakage in the grinding chamber and automatically recovering wafers provided by the present application, when the outer protective layer (bellows) of the cylinder is damaged and liquid enters the liquid leakage detection device, the liquid leakage detection device is triggered to remind the on-duty engineer to perform fault handling through the machine alarm system and automatically recover the wafers in the machine in the first time, avoiding the scrapping of wafers caused by the change of the specific environment during grinding due to the loss of the sealing performance of the grinding chamber, and also avoiding serious safety incidents caused by liquid leakage in the grinding chamber. Therefore, the present application effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0061] The above embodiments only illustratively explain the principles and effects of the present application, rather than limiting the present application. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present application.

Claims

1. A method for detecting liquid leakage in a grinding chamber and automatically recycling wafers, characterized in that The method includes: Step 1: After the liquid leakage detection device using the resistance-capacitance dual-mode collaborative working mechanism detects liquid leakage in the grinding chamber, it triggers a signal to start the emergency event handling program; Step 2: Activate the machine alarm system to remind the on-duty engineer to handle the fault; Step 3: Terminate the supply of the grinding liquid, and the grinding in the grinding chamber stops; Step 4: Recover the wafers through the wafer automatic recovery system; Step 5: System self-check and reset.

2. The method according to claim 1, wherein Under the resistance-capacitance dual-mode collaboration, the resistance signal quickly responds to the conductive liquid, the capacitance signal covers all liquid types, and the resistance and capacitance measurement circuits are alternately activated to avoid signal interference.

3. The method according to claim 1, characterized in that The liquid leakage detection device is a "resistance-capacitance dual-mode sensor" with a cylindrical alternating electrode layout, and there are 4 holes in the middle for the air inlet pipe, air outlet pipe, and the wires of the cylinder lifting sensor to pass through respectively.

4. The method according to claim 3, characterized in that, The alternating electrode layout adopts a circular ring grid electrode alternating layout, with an electrode spacing of 0.5 mm, and the electrodes are plated with a platinum layer or a chromium-nickel layer.

5. The method according to claim 1, wherein The liquid leakage detection device is connected to the machine alarm system and the wafer automatic recovery system.

6. The method according to claim 1, characterized in that In Step 1, when the leakage amount reaches the trigger threshold, the liquid leakage detection device sends a digital signal to the PLC, and after receiving the signal, the PLC starts the emergency event handling program.

7. The method according to claim 6, characterized in that, The trigger threshold is that the leakage amount ≥ 0.5 ml.

8. The method according to claim 1, wherein In Step 2, send an alarm message to the on-duty engineer's mobile phone and PC through the factory MES system.

9. The method according to claim 6, wherein In Step 3, after the PLC sends a closing instruction to the grinding liquid supply device, the solenoid valve is powered off, and the system records the liquid supply stop time and the valve status.

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