Photoresist spraying device and use method thereof

Abstract

The invention provides a photoresist spraying device and a use method thereof. The apparatus includes a nozzle assembly disposed inside a housing having a bottom that can be mechanically opened and closed, and a gravity sensor connected to a control system. In the non-spraying stage, the bottom is closed to receive any photoresist dripping accidentally; and in the spraying stage, the bottom is opened. The method comprises the steps that the bottom is kept closed during moving and waiting, the bottom is opened only when a wafer is sprayed, and the bottom is closed immediately after spraying is completed; meanwhile, a gravity sensor monitors the weight of leakage borne by the bottom in real time and gives an alarm when the weight exceeds a preset threshold value. Through combination of physical blocking and real-time monitoring, wafer defects caused by nozzle drop leakage are effectively prevented, and instant early warning of nozzle faults is realized, so that the product yield is remarkably improved, the material waste is reduced, and the equipment utilization rate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, and particularly to a photoresist spraying device and a method thereof. BACKGROUND

[0002] In the manufacturing process of semiconductor chips, photolithography is a key process step for defining circuit patterns. An important part of the photolithography process is the photoresist coating, i.e. uniformly coating a layer of photoresist on the wafer surface. The traditional coating process usually adopts spin coating method, which dispenses a certain amount of photoresist droplet to the center or a specific position of the wafer through one or more nozzles, and then spreads the photoresist uniformly on the entire wafer surface by high-speed rotation of the wafer under the action of centrifugal force.

[0003] In order to accurately control the amount of photoresist and prevent the residual droplet from falling after the spraying is completed, the nozzle is usually equipped with a back suction function. This function generates negative pressure through valve control to suck back the photoresist droplet that may be hanging at the tip of the nozzle after the spraying instruction is completed. However, the photoresist spraying device in the prior art has several problems. First, the back suction valve is a mechanical component, which may be worn, loose or damaged after long-term use, resulting in failure or incomplete back suction. Once the back suction fails, the residual photoresist droplet may fall from the nozzle opening during the non-spraying stage (e.g. nozzle movement or waiting).

[0004] If the wafer is rotating below at this time, the droplet will fall on the wafer and be splashed away under the action of the huge centrifugal force generated by high-speed rotation, forming a large area of radial or irregularly shaped coating defects. Such defects will directly cause the failure of subsequent exposure, development and other processes, resulting in the scrapping of the chips in the corresponding area, seriously affecting the yield of the product, and significantly increasing the production cost.

[0005] In addition, the prior art generally lacks real-time monitoring capability for the working state of the nozzle, especially the back suction health state. In general, only when the subsequent defect detection process finds that the wafer has coating defects, will the operator realize that the nozzle may have a problem. At this time, multiple wafers have been affected. Subsequent processing methods, such as manual visual inspection of the nozzle or rework of the contaminated wafers, not only have low efficiency, but also the results of visual inspection are easily disturbed by human factors and lack of reliability. More seriously, the accidental dropping of photoresist can also contaminate the equipment cavity, which may need to be stopped for cleaning, thereby reducing the utilization rate and production efficiency of the equipment.

[0006] Therefore, how to effectively prevent photoresist defects caused by nozzle leakage and monitor the nozzle state in real time to discover and handle abnormalities in time is a technical problem to be solved by those skilled in the art.

[0007] To solve the above problems, a new photoresist spraying device and its use method are needed. SUMMARY

[0008] The technical problem to be solved by the present application is to provide a photoresist spraying device and method, aiming to solve the problems of wafer defects caused by nozzle leakage in the prior art, lack of real-time monitoring means, low product yield, material waste and low equipment efficiency.

[0009] Specifically, the nozzle back suction function of the photoresist spraying device in the prior art may fail due to aging or damage, resulting in photoresist leakage during the non-spraying stage. This leakage will directly contaminate the wafer and form a large area of defects in high-speed rotation, seriously affecting the product yield. In addition, the monitoring of the health status of the nozzle is often lagging behind, and manual inspection is usually carried out after the wafer defects are found, which not only responds in a timely manner, causes batch waste and material waste, but also has low efficiency and poor reliability. Artificial inspection, accidental dripping may also contaminate the machine, resulting in costly downtime cleaning and reducing equipment utilization.

[0010] To achieve the above object and other related objects, the present application provides a photoresist spraying device, comprising:

[0011] a nozzle assembly comprising at least one nozzle for spraying photoresist;

[0012] a housing, the nozzle assembly is arranged inside the housing, the housing has a bottom which can be mechanically opened and closed, for receiving the photoresist dripping from the nozzle when the bottom is closed, and allowing the nozzle to spray photoresist outward when the bottom is opened; and

[0013] a gravity sensor arranged at the bottom of the housing, the gravity sensor is electrically connected with the control system, for detecting the weight of the photoresist received by the bottom, and generating an alarm signal when the weight exceeds a preset threshold.

[0014] Preferably, the housing is a semi-enclosed housing for wrapping the nozzle assembly while avoiding forming a closed space that changes the back suction pressure of the nozzle.

[0015] Preferably, the bottom of the housing is detachable for cleaning or replacing after receiving the dripping photoresist.

[0016] Preferably, it further comprises a hanging bracket connected with the housing for being clamped by a mechanical arm to move the photoresist spraying device.

[0017] Preferably, the nozzle assembly comprises a plurality of nozzles, and the mechanically openable and closable bottom of the housing is configured to selectively allow one or more of the plurality of nozzles to spray photoresist outwardly by the opening and closing action thereof.

[0018] Correspondingly, the application also provides a method for using the photoresist spraying device, comprising:

[0019] Step one, moving the photoresist spraying device above the wafer to be processed, at this time the bottom of the housing is in a closed state;

[0020] Step two, opening the bottom of the housing, spraying photoresist onto the wafer through the nozzles, and closing the bottom of the housing after the spraying is completed;

[0021] Step three, during the operation of the photoresist spraying device, the weight of the dripping photoresist received by the bottom of the housing is monitored in real time through the gravity sensor; and

[0022] Step four, when the weight exceeds a preset threshold, an alarm is issued.

[0023] Preferably, in step two, photoresist is sprayed onto the wafer during the rotation of the wafer.

[0024] Preferably, the method further comprises: step five, after the spraying is completed, moving the photoresist spraying device to an empty area.

[0025] Preferably, the method further comprises: after the alarm is issued, performing a disposal action of replacing the nozzle assembly or the nozzle in the nozzle assembly that drips.

[0026] Preferably, the preset threshold is the weight of one or more photoresist droplets.

[0027] As described above, the photoresist spraying device and the method for using the same have the following beneficial effects:

[0028] The application can effectively intercept any accidental dripping of the photoresist from the nozzles by closing the bottom during the non-spraying stage, thereby fundamentally eliminating the risk of contamination of the wafer by dripping. By introducing the gravity sensor, the application can monitor the back suction health status of the nozzles in real time, and once dripping occurs, the application can detect the slight weight change in the first time and trigger an alarm. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure shows a schematic diagram of the photoresist spraying device of the application;

[0030] Figure 2Figure 1 shows a schematic diagram of a method of using the photoresist spraying device of the present application. DETAILED DESCRIPTION

[0031] Other advantages and benefits of the present application will become apparent to those skilled in the art upon consideration of the disclosure or can be learned by practice of the application. The present application can be realized and achieved by means of the structures and combinations described in this specification and it is therefore to be understood that various modifications and changes can be made by those skilled in the art without departing from the spirit of the present application.

[0032] Referring to Figure 1 The present application provides a photoresist spraying device, comprising:

[0033] A nozzle assembly, a housing 101, and a gravity sensor arranged at the bottom 102 of the housing 101.

[0034] The nozzle assembly comprises at least one nozzle 103 for spraying photoresist.

[0035] In some embodiments, the nozzle assembly comprises a plurality of nozzles 103, and the mechanically openable and closable bottom 102 of the housing 101 is configured to selectively allow one or more of the plurality of nozzles 103 to spray photoresist outward by its opening and closing action. This design provides higher flexibility and accuracy, especially suitable for processes that require the use of different types of photoresist or complex coating patterns. The control system can accurately control the opening and closing of the bottom 102 door according to the process requirements, and only expose the nozzles 103 that are currently needed for work, achieving precise control of different photoresist spraying and avoiding the risk of accidental dripping of non-working nozzles 103.

[0036] To achieve this selective exposure, the mechanical opening and closing structure of the bottom 102 can be designed in various forms.

[0037] For example, in one specific implementation, the plurality of nozzles 103 are arranged in a straight line, and the bottom 102 of the housing 101 can be designed as a sliding baffle with a single opening. When a specific nozzle 103 (such as No. 2 nozzle 103) needs to be used, the control system drives the sliding baffle to move so that its opening is accurately aligned directly below the No. 2 nozzle 103, thereby providing a spraying channel only for this nozzle 103, while other nozzles 103 (such as No. 1 and No. 3 nozzles 103) are still covered by the solid part of the baffle, thereby being effectively isolated.

[0038] In another specific implementation, the bottom 102 of the housing 101 can be composed of multiple independent door segments, each corresponding to a nozzle 103. When a menu instruction requires the use of a certain nozzle 103, the control system only drives the door segment corresponding to that nozzle 103 to open, while the rest of the door segments remain closed. For example, if the apparatus is configured with two nozzles 103 for spraying bottom anti-reflective coating (BARC) and photoresist respectively, when performing the BARC coating step, only the door segment underneath the BARC nozzle 103 is opened; when performing the photoresist coating step, the BARC door segment is closed and the door segment underneath the photoresist nozzle 103 is opened. Through this door control mechanism accurate to a single nozzle 103, the precision of process control and the protection capability of the apparatus are greatly enhanced.

[0039] The nozzle assembly is disposed inside the housing 101, which has a bottom 102 that can be mechanically opened and closed, for receiving the photoresist dripped from the nozzle 103 when the bottom 102 is closed, and allowing the nozzle 103 to spray photoresist outward when the bottom 102 is opened. When the bottom 102 is closed, the housing 101 acts as a protective cover and collection tray, effectively intercepting any accidental drips of the photoresist due to damage or relaxation of the nozzle 103 back suction valve, thereby fundamentally avoiding the liquid droplets from falling on the wafer 106 surface which is highly sensitive. This directly eliminates the large-area defects caused by the liquid droplets being splashed when the wafer 106 is rotating at high speed, providing a solid guarantee for improving the final product yield. When spraying is required, the mechanical opening action of the bottom 102 can accurately expose the nozzle 103, ensuring that the normal coating operation is not affected.

[0040] In some embodiments, the housing 101 is a semi-enclosed housing 101, which is used to wrap the nozzle assembly while avoiding forming a closed space that changes the back suction pressure of the nozzle 103. Specifically, this "semi-enclosed" structure means that the housing 101 is not a completely sealed container. For example, the housing 101 can be designed as a cover with a U-shaped or C-shaped cross-section, which mainly covers the side and bottom of the nozzle assembly, while the top or part of the side remains open. Alternatively, the housing 101 can also be a structure roughly in the shape of a cylinder or a square box, but with several ventilation openings, grilles or cavities on its side wall or upper wall that are connected to the outside environment. The presence of these openings ensures that the air inside the housing 101 can flow freely, so that the internal air pressure is always balanced with the atmospheric pressure of the machine environment. It provides sufficient shielding to prevent dripping while maintaining communication with the outside environment, ensuring that the air pressure around the nozzle 103 does not fluctuate dramatically due to the introduction of the housing 101. This is crucial for maintaining the stability and reliability of the back suction function of the nozzle 103, effectively avoiding the new problem of back suction failure caused by changes in cavity pressure.

[0041] In some embodiments, the bottom 102 of the housing 101 is detachable for cleaning or replacement after receiving the dropped photoresist. This design greatly improves the maintainability of the device. Once a drop occurs and is detected by the system, the operator can easily remove the bottom 102 containing the waste liquid for cleaning or directly replace a clean spare bottom 102. This not only effectively prevents the spread of photoresist contaminants inside the machine, but also avoids the time-consuming and labor-intensive cleaning process, significantly shortens the maintenance time of the device due to abnormalities, reduces manpower and cleaning costs, and thus improves the overall utilization and production efficiency of the machine.

[0042] The gravity sensor is arranged at the bottom 102 of the housing 101 and is electrically connected with the control system, for detecting the weight of the photoresist received by the bottom 102 and generating an alarm signal when the weight exceeds a preset threshold. It can monitor the working health status of the nozzle 103 in real time, especially the integrity of its back suction function. Compared with the traditional technology which can only find defects in the wafer 106 to trace back the problem, the present application can issue an alarm at the first time of the drop event. This allows the operator or the automatic system to intervene immediately, not only to save the subsequent wafers 106 to be processed, but also to minimize the waste of expensive photoresist materials, while eliminating the dependence on inefficient and unreliable manual visual inspection.

[0043] In some embodiments, the device further comprises a suspension frame 105 connected with the housing 101 for being gripped by the mechanical arm 104 to move the entire photoresist spraying device. The suspension frame 105 realizes the synchronous and coordinated movement of the spraying device and the mechanical arm 104, thereby ensuring the need for high-precision positioning, movement and operation of the device above the wafer 106.

[0044] Please refer to Figure 2 The present application also provides a method for improving wafer defects in the photoresist spraying process, comprising the following steps:

[0045] Step one, move the photoresist spraying device as claimed in any one of the preceding embodiments above the wafer 106 to be processed, at this time the bottom 102 of the housing 101 is in a closed state. Keep the bottom 102 closed during the movement and positioning of the device to provide a key physical barrier for the wafer 106, ensuring that there is no accidental dripping of the liquid to contaminate the wafer 106 surface during the preparation stage before formal spraying, and ensuring the cleanliness of the process start.

[0046] Step two, open the bottom 102 of the enclosure 101, spray photoresist onto the wafer 106 through the nozzle 103, and close the bottom 102 of the enclosure 101 after the spraying is completed. The exposure time window of the nozzle 103 can be precisely limited to only the necessary spraying time. Once the spraying is completed, the protective barrier is immediately restored, achieving precise control of the spraying process and continuous protection of the wafer 106.

[0047] In some embodiments, in step two, photoresist is sprayed onto the wafer 106 during the rotation of the wafer 106. This is a standard operation to achieve a spin coating process, by applying photoresist to a high-speed rotating wafer 106, using centrifugal force to spread the liquid evenly to all directions, and finally forming a photoresist film layer with high uniformity in thickness on the surface of the wafer 106.

[0048] Step three, during the operation of the photoresist spraying device, the weight of the dripping photoresist received by the bottom 102 of the enclosure 101 is monitored in real time by the gravity sensor.

[0049] Step four, when the weight exceeds the preset threshold, an alarm is issued. The triggering of the alarm means that the system has automatically identified an abnormality (i.e. nozzle 103 dripping). This immediate feedback mechanism can immediately inform the equipment control system or the on-site operator, thereby initiating subsequent response procedures and effectively preventing the continuous production of substandard products.

[0050] In some embodiments, the preset threshold is the weight of one or more photoresist droplets. By setting the threshold at a very low level, such as the weight of a single droplet, the system can be given a very high detection sensitivity. This ensures that even the slightest dripping phenomenon can be immediately captured in its initial stage, thereby maximizing the preventive and protective effects of the real-time monitoring system.

[0051] In some embodiments, the method further comprises, after the alarm is issued, performing a disposal action of replacing the nozzle assembly or the nozzle 103 in the nozzle assembly that is dripping. Once the system alarms, a standardized maintenance procedure can be immediately initiated, the normal production capacity of the equipment can be restored in the shortest time by quickly replacing the problematic nozzle 103 module, and the impact of abnormal events on overall productivity can be minimized.

[0052] In some embodiments, the method further comprises step five, after the spraying is completed, moving the photoresist spraying device to an empty area. This step moves the completed tool module out of the critical process area (such as above the wafer 106 chuck), freeing up space for subsequent process steps (such as wafer 106 baking or conveying), while also minimizing the risk of any potential sources of contamination remaining in the core area.

[0053] It is to be noted that the drawings provided in the present embodiment only schematically illustrate the basic concept of the present application, and only the components related to the present application are shown in the drawings, rather than being drawn according to the number, shape and size of the components in actual implementation. The shape, number and ratio of each component in actual implementation can be arbitrarily changed, and the layout pattern of the components can be more complex.

[0054] The above-described embodiments only illustratively explain the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above-described embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed in the present application should be covered by the claims of the present application.

Claims

1. A photoresist spraying apparatus, characterized in that, include: A nozzle assembly, the nozzle assembly including at least one nozzle for spraying photoresist; The housing has the nozzle assembly disposed inside it, and the housing has a mechanically openable and closable bottom for receiving photoresist dripping from the nozzle when the bottom is closed, and for allowing the nozzle to spray photoresist outward when the bottom is open; as well as A gravity sensor is installed at the bottom of the housing. The gravity sensor is electrically connected to the control system and is used to detect the weight of the photoresist supported at the bottom. When the weight exceeds a preset threshold, an alarm signal is generated.

2. The photoresist spraying apparatus according to claim 1, characterized in that: The outer casing is a semi-enclosed casing, used to enclose the nozzle assembly while avoiding the formation of a sealed space that would change the nozzle back suction pressure.

3. The photoresist spraying apparatus according to claim 1 or 2, characterized in that: The bottom of the housing is removable for cleaning or replacement after catching dripping photoresist.

4. The photoresist spraying apparatus according to claim 1, characterized in that: It also includes a suspension bracket connected to the housing for being gripped by a robotic arm to move the photoresist spraying device.

5. The photoresist spraying apparatus according to claim 1, characterized in that: The nozzle assembly includes a plurality of nozzles, and the mechanically openable and closable bottom of the housing is configured to selectively allow one or more of the plurality of nozzles to spray photoresist outward by means of its opening and closing action.

6. The method of using the photoresist spraying apparatus according to any one of claims 1 to 5, characterized in that, include: Step 1: Move the photoresist spraying device above the wafer to be processed, at which time the bottom of the outer shell is closed; Step 2: Open the bottom of the housing, spray photoresist onto the wafer through the nozzle, and close the bottom of the housing after spraying is completed; Step 3: During the operation of the photoresist spraying device, the weight of the dripping photoresist received at the bottom of the housing is monitored in real time by the gravity sensor; as well as Step 4: When the weight exceeds a preset threshold, an alarm is issued.

7. The method of using the photoresist spraying apparatus according to claim 6, characterized in that: In step two, photoresist is sprayed onto the wafer during the wafer rotation process.

8. The method of using the photoresist spraying apparatus according to claim 6, characterized in that: The method further includes: step five, after the spraying is completed, moving the photoresist spraying device to an empty area.

9. The method of using the photoresist spraying apparatus according to claim 6, characterized in that: The method further includes, after issuing an alarm, performing actions to replace the nozzle assembly or to handle the nozzle in the nozzle assembly that is leaking.

10. The method of using the photoresist spraying apparatus according to claim 6, characterized in that: The preset threshold is the weight of one or more photoresist droplets.

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