Method and device for dynamically adjusting path and airflow to improve photoresist film quality

Abstract

The application discloses a method and device for improving photoresist film layer quality by dynamic path and airflow assistance, and the method comprises the following steps: fixing an atomizing nozzle in an inclined manner and arranging an auxiliary airflow device; dividing an S-shaped scanning path into a long straight path segment, a short straight path segment and a turning path segment connecting the two; in the spraying process, the movement speed of the atomizing nozzle is acquired in real time, and the spraying flow and the auxiliary airflow pressure are dynamically linked and adjusted based on the speed to keep the deposition amount per unit area constant. Through dynamic segmented linkage control, the application effectively solves the problems of local film layer over-thickness, particle escape and pinhole defects caused by too long residence time of the turning path segment, and significantly improves the uniformity, compactness and quality of the photoresist film layer.

Description

Technical Field

[0001] This invention belongs to the field of wafer coating and advanced packaging technology, and particularly relates to a method and apparatus for improving the quality of photoresist film layers with dynamic path and airflow assistance. Background Technology

[0002] In advanced semiconductor manufacturing, photolithography is a crucial step in realizing microstructures and circuit patterns. The preparation of photoresist films is a key process, and its performance directly impacts chip production quality and yield. During photoresist spraying, the consistency and surface quality of the film are paramount. However, due to environmental factors, spraying conditions, and material properties, film defects are still difficult to avoid. These defects not only lead to distortion of the photolithographic pattern but may also cause short circuits or open circuits in subsequent etching or interlayer bonding, severely affecting development resolution and the stability of subsequent processes.

[0003] There are three common methods to eliminate defects in photoresist film layers: (1) As in patents CN113126441B and CN122183915A, the characteristics of the wafer surface are changed to ensure complete fusion between photoresist droplets, thereby effectively preventing the generation of pinhole defects. Similar methods include using standard RCA cleaning to remove organic, inorganic and metal ion contamination. Or, a thickening agent, such as HMDS (hexamethyldisilazane) vacuum oven vapor deposition, is used. After HMDS vacuum oven treatment, the hydrophilic substrate surface can become hydrophobic, which greatly improves the wettability and adhesion of the photoresist. However, the pretreatment of the wafer surface cannot be used for multilayer photoresist spraying. (2) As in patent CN121165399B, the thickness of the thin film layer is increased to eliminate pinhole defects. However, this method will bring great challenges to the photolithography process. Generally speaking, the resolution of photolithography technology is about 5-8 times the thickness of the thin film. Thick photoresist films will produce more severe lateral photochemical reactions due to light scattering of the film layer, which will lead to a decrease in the resolution of the photolithography pattern. Therefore, it is necessary to effectively suppress pinhole defects on the surface of the photoresist film. (3) For example, patents CN115502048B and CN109870880A, by adding additional equipment or post-processing, but these methods not only fail to eliminate existing film defects, but also add additional process steps, further reducing production efficiency.

[0004] In current photoresist spraying processes, defects in the photoresist film layer are a common technical challenge in the industry and a major obstacle to improving the yield of photolithography processes. Existing photoresist spraying processes generally use an S-shaped scanning path for coating and are usually set to steady-state uniform speed spraying, failing to fully consider the impact of acceleration and deceleration processes during bends on film quality. Because the moving platform needs to undergo deceleration, turning, and re-acceleration in the bends, the nozzle's dwell time in this area increases significantly, leading to a corresponding increase in localized photoresist deposition. Simultaneously, the solvent evaporation characteristics change, easily causing uneven film thickness and the formation of pinhole defects in this area. Furthermore, the auxiliary airflow in existing solutions maintains a constant direction and intensity throughout the spraying process, failing to effectively match the movement trajectory when the nozzle changes speed or direction. This significantly reduces the physical isolation effect on escaping particles, making it difficult to guarantee the integrity of the coated area. Summary of the Invention

[0005] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a method and apparatus for improving the quality of photoresist film layer with dynamic path and airflow assistance. Through dynamic segmented linkage control, the problem of uneven film thickness and pinhole defects in the bending section is solved, so as to achieve the preparation of high-quality photoresist film layer.

[0006] Technical solution: To achieve the above objectives, the present invention provides a method for improving the quality of a photoresist film layer with dynamic path and airflow assistance, comprising the following steps:

[0007] Step 1: Tilt and fix the atomizing nozzle on the adhesive application platform, and set an auxiliary airflow device below the atomizing nozzle. Adjust the relative position of the atomizing nozzle and the auxiliary airflow device.

[0008] Step 2: Pre-process the wafer and fix it on the vacuum chuck, then heat it to the preset temperature;

[0009] Step 3: Turn on the drive device of the atomizing nozzle, the air supply device of the guide airflow and the auxiliary airflow, and start the photoresist flow pump to put the atomizing nozzle into a stable atomization working state.

[0010] Step 4: Control the motion mechanism to drive the atomizing nozzle to spray the wafer according to the preset S-shaped scanning path;

[0011] In step four, the S-shaped scanning path is divided into a long straight path segment S1, a short straight path segment S3, and a turning path segment S2 connecting the two. During the spraying process, the real-time movement speed V(t) of the atomizing nozzle is obtained, and the real-time spraying flow rate Q(t) and the real-time auxiliary airflow pressure P(t) are dynamically adjusted based on the real-time movement speed V(t) to maintain a constant amount of photoresist deposition per unit area of ​​the wafer and suppress local film thickness, particle escape, and pinhole defects caused by the nozzle staying in the turning path segment S2 for a longer time.

[0012] After the coating is completed, the wafer is rotated to clean the atomizing nozzle.

[0013] Furthermore, in the aforementioned dynamic linkage adjustment:

[0014] The real-time spraying flow rate Q(t) is calculated by using the real-time movement speed V(t) as a speed linkage term, the overlap compensation factor between adjacent spraying channels, and the solvent evaporation compensation factor. The functional relationship satisfies: Q(t)=k·V(t)·[1 / (1+f(r))]·[1+g(t)], where k is the proportionality coefficient, f(r) is the overlap compensation factor between adjacent spraying channels, and g(t) is the solvent evaporation compensation factor;

[0015] The linkage function of the real-time auxiliary airflow pressure P(t) is: P(t) = P1·[V(t) / V1] β V1 is the set speed of the long straight path segment S1, P1 is the set air pressure of the long straight path segment S1, and β is the air pressure-speed linkage index, with a value range of 0.4 to 0.8, to ensure that sufficient constrained airflow is maintained at low speeds, while avoiding excessive air pressure that blows away the deposited droplets.

[0016] Furthermore, the S-shaped scanning path is specifically divided into five control sub-stages:

[0017] Phase A: Long straight-line constant speed section, the atomizing nozzle moves at a constant speed V1;

[0018] Phase B: Deceleration phase before turning, the atomizing nozzle speed decreases from V1 to the minimum turning speed V. turn The speed decreases smoothly in a trapezoidal or S-shaped curve.

[0019] Phase C: Turning and steering section, the atomizing nozzle speed is maintained at V. turn Or approximately zero, the direction of motion is reversed;

[0020] Phase D: Acceleration phase after turning, the atomizing nozzle speed changes from V... turn Increase to the target speed V2 for the short straight-line movement;

[0021] Phase E: Short straight-line speed-changing section, during which the atomizing nozzle experiences acceleration, a brief period of constant speed, and deceleration.

[0022] Among them, sub-stage A constitutes the long straight path segment S1, sub-stages B, C, and D together constitute the turning path segment S2, and sub-stage E constitutes the short straight path segment S3.

[0023] Furthermore, in the short straight path segment S3, a variable step size spraying or a specific compensation mechanism for overlapping areas is adopted;

[0024] Set the step distance d = W(1-r), where W is the effective spray width and r is the overlap rate of adjacent passes, with a value range of 0.2 to 0.5. Based on the ratio of the nozzle diameter of the atomizing nozzle to the length of the short straight path segment S3, recalculate the spray flow rate Q(t) in sub-stage E to achieve a smooth transition of film thickness in the overlapping area at the junction of the short straight path segment S3 and the long straight path segment S1.

[0025] Furthermore, in step four, when the atomizing nozzle enters the turning path segment S2, the air outlet control mode of the auxiliary airflow device is switched:

[0026] Switch from constant oblique blowing mode to rotating auxiliary airflow mode or pulsed auxiliary airflow mode;

[0027] In the rotating auxiliary airflow mode, the outlet direction of the auxiliary airflow rotates synchronously with the movement direction of the atomizing nozzle; in the pulsed auxiliary airflow mode, the auxiliary airflow is intermittently ejected according to a preset frequency and duty cycle, providing a brief spreading and fusion time for the photoresist droplets in a low-speed state.

[0028] Furthermore, the tilt angle of the atomizing nozzle is 20° to 80°; the airflow angle of the auxiliary airflow matches the tilt direction of the atomizing nozzle, and is 20° to 80°.

[0029] The gas flow rate of the auxiliary airflow is 1 / 2 of the flow rate of the atomizing nozzle guide airflow; the auxiliary airflow device is located directly below the nozzle baffle, its width is greater than the width of the nozzle atomizing surface, and the distance between the outlet of the auxiliary airflow and the wafer surface is less than 5mm.

[0030] Furthermore, the atomizing nozzle is a liquid ultrasonic nozzle, a pressurized single-fluid nozzle, a gas-assisted two-fluid nozzle, or an electrostatic atomizing nozzle; the photoresist is a positive photoresist or a negative photoresist.

[0031] The vacuum chuck is a heating stage with a heating temperature of 80°C. Heating accelerates the evaporation of solvent in the photoresist and reduces its fluidity.

[0032] A device for improving the quality of a photoresist film layer with dynamic path and airflow assistance, and a method for improving the quality of a photoresist film layer with dynamic path and airflow assistance, comprising a motion mechanism, an atomizing nozzle, a guide airflow supply module, an auxiliary airflow module, a flow pump, a heated vacuum chuck, and a control module;

[0033] The atomizing nozzle is mounted at an angle on the motion mechanism and is connected to a guide airflow inlet and a photoresist solution delivery inlet.

[0034] The auxiliary airflow module includes a gas chamber, a gas buffer chamber, and an auxiliary airflow inlet, located below the atomizing nozzle, and its width is greater than the width of the atomizing surface of the atomizing nozzle.

[0035] The control module is connected to the motion mechanism, the flow pump, and the auxiliary airflow module respectively, and is used to receive the motion speed signal of the atomizing nozzle in real time and adjust the spray flow rate and auxiliary airflow pressure in real time.

[0036] Furthermore, the auxiliary airflow module also includes an airflow direction and frequency adjustment mechanism, including a miniature stepper motor and / or a high-frequency solenoid valve mounted on the gas chamber;

[0037] The micro stepper motor is used to drive the auxiliary air outlet to rotate, so as to realize the rotational auxiliary airflow in the turning path section S2; the high-frequency solenoid valve is used to control the frequency and duty cycle of airflow interruption, so as to realize the pulsed auxiliary airflow in the turning path section S2.

[0038] Furthermore, the control module has a pre-stored speed-flow-pressure linkage model, which includes a speed linkage term, an overlap compensation factor for adjacent spray lines, a solvent evaporation compensation factor, and a β pressure-speed linkage index.

[0039] The control module automatically switches control strategies according to the current path segment of the motion mechanism, and controls the atomizing nozzle, guide airflow, auxiliary airflow and flow pump to achieve the preparation of a photoresist film layer with no pinhole defects and uniform thickness.

[0040] Beneficial effects: This invention is based on dynamic path segmented linkage control, which monitors the movement speed in real time and adjusts the spraying flow rate and auxiliary air pressure synchronously. This ensures that the amount of photoresist deposited per unit area on the wafer surface is constant, and completely eliminates the defects of local over-thickness and pinhole aggregation caused by excessive dwell time in the turning section. At the same time, the auxiliary airflow adaptively matches the movement state, maintaining effective particle constraint at low speeds and avoiding excessive purging that causes new liquid film damage. This significantly improves the uniformity, density and defect resistance of the photoresist film layer, ensuring high-precision transfer of subsequent photolithography patterns and improving yield. Attached Figure Description

[0041] Figure 1This is a schematic diagram of the structure for spraying coating along an S-shaped scanning path using an atomizing nozzle.

[0042] Figure 2 This is a schematic diagram of a spraying operation performed under the action of an auxiliary airflow.

[0043] Figure 3 This is a magnified microscopic diagram of the adhesive layer on the surface of a wafer with pinhole defects.

[0044] Figure 4 This is a magnified microscopic diagram of the adhesive layer on the wafer surface during spraying under the dynamic path segmentation control of the present invention. Detailed Implementation

[0045] The invention will now be further described with reference to the accompanying drawings.

[0046] like Figure 1 and Figure 2As shown, a method and apparatus for improving the quality of a photoresist film layer with dynamic path and airflow assistance are disclosed. The method includes the following steps: Step 1: The atomizing nozzle is tilted and fixed on the coating motion platform, and an auxiliary airflow device is set below the atomizing nozzle. The relative positions of the atomizing nozzle and the auxiliary airflow device are adjusted. Step 2: The wafer is pre-treated and adsorbed and fixed on a vacuum chuck, and heated to a preset temperature. Step 3: The driving device of the atomizing nozzle, the air supply device of the guide airflow and the auxiliary airflow are turned on, and the photoresist flow pump is started to put the atomizing nozzle into a stable atomizing working state. Step 4: The motion mechanism 11 is controlled to drive the atomizing nozzle 12 to spray the wafer 13 according to the preset S-shaped scanning path 10, and the photoresist droplets 15 are attached to the wafer 13 to form a photoresist film layer 16. In step four, the S-shaped scanning path is divided into a long straight path segment S1, a short straight path segment S3, and a turning path segment S2 connecting the two. During the spraying process, the real-time movement speed V(t) of the atomizing nozzle is acquired. Based on the real-time movement speed V(t), the real-time spraying flow rate Q(t) and the real-time auxiliary airflow pressure P(t) are dynamically adjusted to maintain a constant amount of photoresist deposition per unit area of ​​the wafer and suppress local over-thickness, particle escape, and pinhole defects caused by the nozzle's longer residence time in the turning path segment S2. After spraying, the wafer is rotated to clean the atomizing nozzle. In this invention, the tilted setting of the atomizing nozzle serves to significantly reduce the vertical impact force of photoresist droplets on the wafer surface compared to traditional vertical spraying, thereby effectively suppressing the free escape of photoresist particles caused by the guide airflow rebound effect. An auxiliary airflow device is installed below the nozzle, which uses high-speed airflow to form a directional "aerodynamic barrier" between the nozzle and the wafer surface. Since the width of the auxiliary airflow 14 is greater than the width of the nozzle atomization surface, this barrier can completely engulf and push any tiny photoresist droplets that may drift backward towards the uncoated area, preventing them from depositing on the already coated surface. More importantly, this invention breaks the fixed pattern of "uniform speed and constant parameters" in the traditional S-shaped scanning path. In conventional processes, the nozzle inevitably undergoes deceleration, turning, and re-acceleration in the turning section of the path. This process causes the residence time of the nozzle per unit area to increase non-linearly, resulting in a sharp increase in local photoresist deposition. At the same time, since the substrate is heated, the solvent evaporation rate accelerates over time, causing fluctuations in the viscosity and solid content of the photoresist in this area. This invention, however, acquires the motion speed V(t) in real time and uses this signal to synchronously and dynamically adjust the spray flow rate Q(t) and the auxiliary airflow pressure P(t) to maintain the goal of "conservation of photoresist deposition per unit area".As the speed decreases, the flow rate is reduced in time to avoid local over-thickness; while the synchronous adjustment of the auxiliary air pressure ensures that the dynamic air curtain can effectively maintain the constraint force on the escaping particles at different speeds, thereby completely eliminating defects such as pinhole aggregation and uneven thickness caused by acceleration and deceleration, so that the photoresist film layer maintains extremely high uniformity and density throughout the entire path.

[0047] In the dynamic linkage adjustment: the real-time spraying flow rate Q(t) is calculated by using the real-time motion speed V(t) as the speed linkage term, the adjacent spraying channel overlap compensation factor, and the solvent evaporation compensation factor, and their functional relationship satisfies: Q(t)=k·V(t)·[1 / (1+f(r))]·[1+g(t)], where k is the proportionality coefficient, f(r) is the adjacent spraying channel overlap compensation factor, and g(t) is the solvent evaporation compensation factor; the linkage function of the real-time auxiliary airflow pressure P(t) is: P(t)=P1·[V(t) / V1] βV1 is the set speed of the long straight path segment S1, P1 is the set air pressure of the long straight path segment S1, and β is the air pressure-speed linkage index, with a value range of 0.4 to 0.8, to ensure that sufficient constrained airflow is maintained at low speeds, while avoiding excessive air pressure that blows away the deposited droplets. In this embodiment, the proportionality coefficient k is determined by the structural parameters of the atomizing nozzle (such as nozzle aperture and atomization surface area) and the physical properties of the photoresist solution (such as concentration and density), and serves as a bridge for the direct linear conversion between the velocity term and the flow rate term. V(t), as the velocity linkage term, is the core benchmark term to ensure a constant deposition amount. The overlapping compensation factor f(r) for adjacent spray lanes is introduced because there is an overlapping area (overlap rate r is 0.2 to 0.5) between adjacent spray lanes in the S-shaped scanning trajectory. The deposition amount per unit area in the overlapping area will increase exponentially, so f(r) needs to be introduced to predict and reduce the flow rate output in this area. The solvent evaporation compensation factor g(t) takes into account that in the high-temperature environment of 80°C on the heating stage, the evaporation rate of solvents such as acetone in the photoresist droplets increases significantly with the residence time. In order to ensure that the solid content of the final photoresist film remains unchanged, the pump flow rate needs to be compensated accordingly based on the evaporation amount. For the coordinated control of the auxiliary airflow pressure P(t), a nonlinear exponential relationship is introduced (β ranges from 0.4 to 0.8), and this range is extremely critical: since β is less than 1, when the nozzle velocity V(t) decreases, the decrease in air pressure P(t) is much smaller than the decrease in velocity. The principle of this nonlinear matching is that at low speeds, the horizontal momentum of the photoresist droplets is greatly weakened. If the air pressure also decreases significantly, it is easy to lose effective restraint on escaping particles; while maintaining a higher air pressure can ensure that the air curtain maintains strong isolation capabilities. At the same time, since β will not be too small (i.e., the air pressure will not increase indefinitely), it avoids the problem of excessive air pressure blowing the wet photoresist droplets already deposited on the wafer surface away from the substrate during deceleration and turning, thus preventing new "wind-blown depressions" defects. Therefore, under complex variable-speed motion conditions, the constraint state of the photoresist particles and the stability of the liquid film achieve a dynamic balance.

[0048] Here, it should be noted that:

[0049] (1) The compensation factor for the overlap of adjacent spray lines is f(r) = r / (1-r).

[0050] (2) Solvent evaporation compensation factor g(t) = α·Δt (where α is a constant related to the temperature of the heating stage and the solvent evaporation rate, set according to the experiment or material parameters, and Δt is the change in the residence time of the atomizing nozzle at a certain point).

[0051] More preferably, the specific value of β is in the range of 0.5 to 0.7, so as to obtain better film uniformity.

[0052] The S-shaped scanning path is specifically divided into five control sub-stages: Stage A: Long straight constant speed section, the atomizing nozzle moves at a constant speed V1; Stage B: Deceleration section before turning, the speed of the atomizing nozzle decreases from V1 to the minimum speed V1 before turning. turn The speed decreases smoothly in a trapezoidal or S-shaped curve; Stage C: the turning and steering section, the atomizing nozzle speed is maintained at V. turn Or approximately zero, the direction of motion reverses; Stage D: acceleration phase after turning, the speed of the atomizing nozzle changes from V turn The speed increases to the short straight target speed V2; Stage E: Short straight speed change section, where the atomizing nozzle experiences acceleration, a brief period of constant speed, and deceleration. Specifically, sub-stage A constitutes the long straight path segment S1, sub-stages B, C, and D together constitute the turning path segment S2, and sub-stage E constitutes the short straight path segment S3. In stage B (i.e., the deceleration section before the turn), the speed decreases smoothly in a trapezoidal or S-shaped curve. The principle is that the S-shaped or trapezoidal speed curve can significantly reduce the acceleration impact of the moving mechanism during reversal, thereby avoiding mechanical vibration-induced droplet splashing, and providing sufficient response time for the control system to perform dynamic adjustments of Q(t) and P(t). It should be noted that, for the speed change in stage D (i.e., the acceleration section after the turn), in a further preferred embodiment of the present invention, stage D also preferably adopts a "trapezoidal" or "S-shaped" curve for a smooth increase (i.e., from V... turn The smooth transition to V2 is achieved by the following principle: the smooth acceleration in stage D forms a complete motion symmetry with the smooth deceleration in stage B, effectively eliminating the mechanical inertial impact generated during acceleration after turning. This ensures that the motion within the entire turning path segment S2 (i.e., the three sub-stages B, C, and D) is in a controlled and smooth state, thereby enabling the dynamic linkage control (Q(t), P(t)) to maintain extremely high control accuracy throughout this entire range, preventing droplet scattering or film thickness fluctuations caused by sudden acceleration changes. In stage C (the turning segment), the nozzle speed is extremely low or close to zero. At this time, the controller can accurately reduce the flow rate to the minimum based on the speed feedback of this sub-stage, and rely on the continuous constraint of the auxiliary airflow to push all the stagnant droplets that may be generated during the reverse turning process forward. Stage E is a short straight-line speed-changing segment. Because this segment is short, the nozzle cannot achieve a stable uniform speed state. Therefore, the essence of this segment is a rapid and continuous switching between acceleration, uniform speed, and deceleration. This invention, through its five-stage division, closely integrates dynamic control with motion, making the film thickness growth in each sub-stage highly predictable, thereby significantly improving the controllability of the spraying process.

[0053] In the short straight path segment S3, a variable step-length spraying or overlapping area specific compensation mechanism is adopted; the step distance d = W(1-r) is set, where W is the effective spraying width and r is the overlap rate of adjacent passes, ranging from 0.2 to 0.5; based on the ratio of the nozzle diameter of the atomizing nozzle to the length of the short straight path segment S3, the spraying flow rate Q(t) in sub-stage E is recalculated to achieve a smooth transition of film thickness in the overlapping area at the junction of the short straight path segment S3 and the long straight path segment S1. In this embodiment, the step distance d = W(1-r) is defined as the distance between the center lines of two adjacent scanning trajectories. When the overlap rate r is 0.2 to 0.5, there is a significant overlap between adjacent spraying passes. Since the short straight path segment is extremely short, the overlapping area accounts for a large proportion of the entire short path segment area. If the same flow rate as the long path segment is used, it will inevitably lead to a defect with a huge difference between the edge and the center. Therefore, this invention recalculates the spraying flow rate Q(t) in stage E based on the ratio of the nozzle diameter to the length of the short straight path segment. The principle is as follows: by predicting the area distribution ratio of overlapping and non-overlapping areas in the short path segment through geometric ratio, and based on this, an additional adjustment coefficient is introduced into the flow formula, thereby completely eliminating the boundary effect at the junction of long and short paths, so that the film thickness of the entire wafer surface can be smoothly and seamlessly connected, further improving the consistency of the film layer and the transfer accuracy of the photolithography pattern.

[0054] In step four, when the atomizing nozzle enters the turning path segment S2, the air outlet control mode of the auxiliary airflow device switches: from a constant oblique blowing mode to a rotating auxiliary airflow mode or a pulsed auxiliary airflow mode. In the rotating auxiliary airflow mode, the outlet direction of the auxiliary airflow rotates synchronously with the movement direction of the atomizing nozzle; in the pulsed auxiliary airflow mode, the auxiliary airflow is intermittently ejected at a preset frequency and duty cycle, providing a brief spreading and fusing time for the photoresist droplets at low speeds. In this embodiment, an airflow mode switching strategy is adopted in the turning path segment S2. In the constant oblique blowing mode, the airflow direction is fixed. When the nozzle undergoes a significant direction reversal, the fixed air curtain will inevitably experience "airflow dead angles" or "reverse misalignment." This invention switches the mode to "rotating auxiliary airflow" when entering the turning segment, utilizing a stepper motor to drive the nozzle to rotate synchronously, ensuring that the vector direction of the air curtain remains highly parallel and in the same direction as the instantaneous vector direction of the nozzle movement, thereby forming a dynamic surrounding air wall without dead angles during the transition. Preferably, a "pulsed assisted airflow" mode can also be used, which can use a high-frequency solenoid valve to control the intermittent on / off flow of airflow. Since the nozzle is slow and near stop at the bend, continuous high-pressure airflow can easily damage the newly deposited liquid film. However, by using a pulsed method, the "blowing" phase suppresses particle escape, and the "stopping" phase provides sufficient time for the droplets to spread laterally, fuse, and refill with solvent, thereby suppressing the generation of pinhole defects and ensuring the integrity and density of the film layer under low-speed complex motion conditions.

[0055] The tilt angle of the atomizing nozzle is 20° to 80°, preferably 30° to 60°, which achieves the best balance between reducing droplet impact and maintaining the spray coverage area. The airflow angle of the auxiliary airflow matches the tilt direction of the atomizing nozzle, which is 20° to 80°, preferably 30° to 60°, to ensure that the air curtain direction is coaxial with the atomization spray direction and maximize the aerodynamic constraint effect.

[0056] The auxiliary airflow has a flow rate that is half the flow rate of the atomizing nozzle's guide airflow. The auxiliary airflow device is located directly below the nozzle baffle, its width is greater than the width of the nozzle's atomizing surface, and the distance between the auxiliary airflow outlet and the wafer surface is less than 5 mm, preferably 4 mm. The auxiliary airflow must form a uniform "air cushion" below the nozzle, with a coverage area slightly wider than the spray surface. The closer the outlet is to the wafer surface, the smaller the airflow attenuation. This efficient airflow with a close distance and large coverage area can "push" escaped particles back to the uncoated area in front. Therefore, without increasing additional structural costs, the efficiency of suppressing pinhole defects is maximized.

[0057] The atomizing nozzle is a liquid ultrasonic nozzle, a pressurized single-fluid nozzle, a gas-assisted two-fluid nozzle, or an electrostatic atomizing nozzle, all of which can produce micron-sized droplets.

[0058] The photoresist can be either positive or negative, thus broadening its applicability.

[0059] The vacuum chuck serves as a heating stage, with a heating temperature of 80°C. Heating accelerates the evaporation of the solvent in the photoresist and reduces its fluidity. The high temperature causes the solvent to evaporate rapidly, increasing the curing speed of the photoresist droplets and preventing the liquid photoresist from dripping to lower areas. Simultaneously, the high temperature reduces the surface tension of the solvent, improving the wetting and spreading ability of the photoresist on the wafer surface. This promotes the stable operation of the dynamic control system under various harsh conditions.

[0060] An apparatus for improving the quality of a photoresist film layer with dynamic path and airflow assistance, and a method for improving the quality of a photoresist film layer with dynamic path and airflow assistance, comprising a motion mechanism, an atomizing nozzle, a guide airflow supply module, an auxiliary airflow module, a flow pump, a heated vacuum chuck, and a control module; the atomizing nozzle is obliquely mounted on the motion mechanism and is connected to a guide airflow inlet and a photoresist solution delivery outlet; the auxiliary airflow module includes a gas chamber, a gas buffer chamber, and an auxiliary airflow inlet, located below the atomizing nozzle, and its width is greater than the atomization surface width of the atomizing nozzle; the control module is connected to the motion mechanism, the flow pump, and the auxiliary airflow module respectively, and is used to receive the motion speed signal of the atomizing nozzle in real time and adjust the spraying flow rate and auxiliary airflow pressure in real time. The motion mechanism provides high-precision two-dimensional movement for the atomizing nozzle; the gas buffer chamber in the auxiliary airflow module can eliminate the fluctuation of the air pump and provide a stable and uniform airflow; the control module receives the speed feedback signal from the servo motor / linear motor encoder in the motion mechanism in real time. Based on the real-time signal, the control module controls the flow pump to change the amount of photoresist delivered, and controls the solenoid valve or drive motor of the auxiliary airflow module to change the air pressure.

[0061] More specifically, the auxiliary airflow module also includes an airflow direction and frequency adjustment mechanism, comprising a miniature stepper motor and / or a high-frequency solenoid valve mounted on the gas chamber. The miniature stepper motor drives the auxiliary airflow nozzle to rotate, achieving a rotating auxiliary airflow in the turning path segment S2. The high-frequency solenoid valve controls the frequency and duty cycle of the airflow interruption, achieving a pulsed auxiliary airflow in the turning path segment S2. After receiving the high-frequency pulse signal from the control module, the miniature stepper motor can precisely rotate to any angle, thereby driving the nozzle to rotate synchronously, forming a rotating airflow matching the motion trajectory. The high-frequency solenoid valve, through rapid on / off switching, cuts the continuous airflow into discrete high-frequency air pulses, and the duty cycle of the pulses is adjustable. In the turning path segment S2, the system can choose to use a rotation mode, a pulse mode, or a combination mode of simultaneous rotation and pulse. Therefore, the device not only provides flow compensation for speed changes but also provides a dynamic windbreak for complex directional movements through its mechanical structure, expanding the applicable scenarios and extreme condition handling capabilities of the device of this invention.

[0062] The control module pre-stores a speed-flow-pressure linkage model, which includes a speed linkage term, an overlap compensation factor for adjacent spray lanes, a solvent evaporation compensation factor, and a β-pressure-speed linkage index. The control module automatically switches control strategies based on the current path segment of the motion mechanism and controls the atomizing nozzle, guide airflow, auxiliary airflow, and flow pump to achieve the fabrication of a pinhole-free, uniformly thick photoresist film. Since different path segments differ, the long straight path segment S1 emphasizes basic proportional linkage, the turning path segment S2 emphasizes auxiliary airflow mode switching and pulse compensation, while the short straight path segment S3 emphasizes geometric compensation for overlapping areas. The control module is responsible for seamless strategy switching between different path segments, thereby achieving fully automated intelligent spraying and ensuring the stable fabrication of pinhole-free, uniformly thick photoresist film layers under different substrate sizes, nozzle types, and process formulations.

[0063] like Figure 3 As shown, dense pinholes appear in the film layer on the wafer surface. And as... Figure 4 As shown, the pinholes in the adhesive layer on the wafer surface after spraying under the dynamic path segmentation control of the present invention are almost eliminated, suppressing film defects and improving film uniformity.

[0064] In summary, this invention, based on dynamic path segmented linkage control, monitors the motion speed in real time and synchronously adjusts the spraying flow rate and auxiliary airflow pressure, ensuring a constant deposition amount of photoresist per unit area on the wafer surface. This completely eliminates local over-thickness and pinhole aggregation defects caused by excessive dwell time at bends. Simultaneously, the auxiliary airflow adaptively matches the motion state, maintaining effective particle constraint even at low speeds and avoiding excessive purging that could damage the liquid film. This significantly improves the uniformity, density, and defect resistance of the photoresist film, ensuring high-precision transfer of subsequent photolithography patterns and improving yield.

[0065] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for improving the quality of a photoresist film layer with dynamic path and airflow assistance, characterized in that: Includes the following steps: Step 1: Tilt and fix the atomizing nozzle on the adhesive application platform, and set an auxiliary airflow device below the atomizing nozzle. Adjust the relative position of the atomizing nozzle and the auxiliary airflow device. Step 2: Pre-process the wafer and fix it on the vacuum chuck, then heat it to the preset temperature; Step 3: Turn on the drive device of the atomizing nozzle, the air supply device of the guide airflow and the auxiliary airflow, and start the photoresist flow pump to put the atomizing nozzle into a stable atomization working state. Step 4: Control the motion mechanism to drive the atomizing nozzle to spray the wafer according to the preset S-shaped scanning path; In step four, the S-shaped scanning path is divided into a long straight path segment S1, a short straight path segment S3, and a turning path segment S2 connecting the two. During the spraying process, the real-time movement speed V(t) of the atomizing nozzle is obtained, and the real-time spraying flow rate Q(t) and the real-time auxiliary airflow pressure P(t) are dynamically adjusted based on the real-time movement speed V(t) to maintain a constant amount of photoresist deposition per unit area of ​​the wafer and suppress local film thickness, particle escape, and pinhole defects caused by the nozzle staying in the turning path segment S2 for a longer time. After the coating is completed, the wafer is rotated to clean the atomizing nozzle.

2. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 1, characterized in that: In the aforementioned dynamic linkage adjustment: The real-time spraying flow rate Q(t) is calculated by using the real-time movement speed V(t) as a speed linkage term, the overlap compensation factor between adjacent spraying channels, and the solvent evaporation compensation factor. The functional relationship satisfies: Q(t)=k·V(t)·[1 / (1+f(r))]·[1+g(t)], where k is the proportionality coefficient, f(r) is the overlap compensation factor between adjacent spraying channels, and g(t) is the solvent evaporation compensation factor; The linkage function of the real-time auxiliary airflow pressure P(t) is: P(t) = P1·[V(t) / V1] β V1 is the set speed of the long straight path segment S1, P1 is the set air pressure of the long straight path segment S1, and β is the air pressure-speed linkage index, with a value range of 0.4 to 0.8, to ensure that sufficient constrained airflow is maintained at low speeds, while avoiding excessive air pressure that blows away the deposited droplets.

3. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 1, characterized in that: The S-shaped scanning path is specifically divided into five control sub-stages: Phase A: Long straight-line constant speed section, the atomizing nozzle moves at a constant speed V1; Phase B: Deceleration phase before turning, the atomizing nozzle speed decreases from V1 to the minimum turning speed V. turn The speed decreases smoothly in a trapezoidal or S-shaped curve. Phase C: Turning and steering section, the atomizing nozzle speed is maintained at V. turn Or approximately zero, the direction of motion is reversed; Phase D: Acceleration phase after turning, the atomizing nozzle speed changes from V... turn Increase to the target speed V2 for the short straight-line movement; Phase E: Short straight-line speed-changing section, during which the atomizing nozzle experiences acceleration, a brief period of constant speed, and deceleration. Among them, sub-stage A constitutes the long straight path segment S1, sub-stages B, C, and D together constitute the turning path segment S2, and sub-stage E constitutes the short straight path segment S3.

4. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 3, characterized in that: In the short straight path segment S3, a variable step size spraying or a specific compensation mechanism for overlapping areas is adopted; Set the step distance d = W(1-r), where W is the effective spray width and r is the overlap rate of adjacent passes, with a value range of 0.2 to 0.

5. Based on the ratio of the nozzle diameter of the atomizing nozzle to the length of the short straight path segment S3, recalculate the spray flow rate Q(t) in sub-stage E to achieve a smooth transition of film thickness in the overlapping area at the junction of the short straight path segment S3 and the long straight path segment S1.

5. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 1, characterized in that: In step four, when the atomizing nozzle enters the turning path segment S2, the air outlet control mode of the auxiliary airflow device switches: Switch from constant oblique blowing mode to rotating auxiliary airflow mode or pulsed auxiliary airflow mode; In the rotating auxiliary airflow mode, the outlet direction of the auxiliary airflow rotates synchronously with the movement direction of the atomizing nozzle; in the pulsed auxiliary airflow mode, the auxiliary airflow is intermittently ejected according to a preset frequency and duty cycle, providing a brief spreading and fusion time for the photoresist droplets in a low-speed state.

6. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 1, characterized in that: The tilt angle of the atomizing nozzle is 20° to 80°; the airflow angle of the auxiliary airflow matches the tilt direction of the atomizing nozzle and is 20° to 80°. The gas flow rate of the auxiliary airflow is 1 / 2 of the flow rate of the atomizing nozzle guide airflow; the auxiliary airflow device is located directly below the nozzle baffle, its width is greater than the width of the nozzle atomizing surface, and the distance between the outlet of the auxiliary airflow and the wafer surface is less than 5mm.

7. The method for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 1, characterized in that: The atomizing nozzle is a liquid ultrasonic nozzle, a pressurized single-fluid nozzle, a gas-assisted two-fluid nozzle, or an electrostatic atomizing nozzle; the photoresist is a positive photoresist or a negative photoresist. The vacuum chuck is a heating stage with a heating temperature of 80°C. Heating accelerates the evaporation of solvent in the photoresist and reduces its fluidity.

8. An apparatus for improving the quality of a photoresist film layer with dynamic path and airflow assistance, used to implement the method for improving the quality of a photoresist film layer with dynamic path and airflow assistance as described in any one of claims 1 to 7, characterized in that: It includes a motion mechanism, atomizing nozzle, airflow supply module, auxiliary airflow module, flow pump, heated vacuum chuck, and control module; The atomizing nozzle is mounted at an angle on the motion mechanism and is connected to a guide airflow inlet and a photoresist solution delivery inlet. The auxiliary airflow module includes a gas chamber, a gas buffer chamber, and an auxiliary airflow inlet, located below the atomizing nozzle, and its width is greater than the width of the atomizing surface of the atomizing nozzle. The control module is connected to the motion mechanism, the flow pump, and the auxiliary airflow module respectively, and is used to receive the motion speed signal of the atomizing nozzle in real time and adjust the spray flow rate and auxiliary airflow pressure in real time.

9. The apparatus for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 8, characterized in that: The auxiliary airflow module also includes an airflow direction and frequency adjustment mechanism, including a miniature stepper motor and / or a high-frequency solenoid valve installed on the gas chamber; The micro stepper motor is used to drive the auxiliary air outlet to rotate, so as to realize the rotational auxiliary airflow in the turning path section S2; the high-frequency solenoid valve is used to control the frequency and duty cycle of airflow interruption, so as to realize the pulsed auxiliary airflow in the turning path section S2.

10. The apparatus for improving the quality of a photoresist film layer with dynamic path and airflow assistance according to claim 8, characterized in that: The control module has a pre-stored speed-flow-pressure linkage model, which includes a speed linkage term, an adjacent spray channel overlap compensation factor, a solvent evaporation compensation factor, and a β pressure-speed linkage index. The control module automatically switches control strategies according to the current path segment of the motion mechanism, and controls the atomizing nozzle, guide airflow, auxiliary airflow and flow pump to achieve the preparation of a photoresist film layer with no pinhole defects and uniform thickness.

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