A thin film patterning method

Abstract

This invention relates to the field of additive manufacturing methods, and more particularly to a method for forming thin film patterns. The method includes the following steps: (S.1): stabilizing the liquid material in the dispensing needle at the dispensing port under negative pressure; (S.2): forming a potential difference between the dispensing needle and the substrate, causing the liquid material to form a Taylor cone facing the surface of the substrate; (S.3): contacting the tip of the Taylor cone with the surface of the substrate and moving the dispensing needle to draw the pattern. Compared with existing technologies, the technical solution of this application can increase the moving speed of the dispensing needle to 500 mm / s, significantly improving work efficiency while still ensuring a comparable thin film pattern forming effect. Furthermore, the printing accuracy can be further improved by setting the printing method. Simultaneously, the thickness of the printed film can be less than 1 micrometer, with high flatness.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing methods, and more particularly to a method for forming thin film patterns. Technical Background

[0002] Currently, there are various methods for forming thin film patterns, such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). PVD technologies include physical vapor deposition (such as evaporation, sputtering, ion beam-assisted deposition, etc.) and molecular beam epitaxy, while CVD technologies include thermal CVD, low-pressure CVD, and electrochemical vapor deposition. All of these technologies can deposit thin films on substrates.

[0003] Electrohydrodynamic printing technology is also a common solution in the prior art. For example, Chinese invention patent application number 2016101382178 discloses a control device and method for controlling the resolution of electrohydrodynamic printing. It uses an induced electric field to make the printing solution at the tip of the conductive nozzle form a Taylor cone and overcome the surface tension of the solution to form droplets that are sprayed downwards. In the flight area of ​​the sprayed droplets, a high-resolution printed pattern is formed. However, this printing method is greatly affected by the moving speed of the nozzle. When the nozzle moves too fast, the connection between the liquid at the nozzle and the substrate will be broken. This is because the replenishment speed of the liquid at the nozzle is less than the speed at which the liquid is carried away by the substrate. In this case, this defect is often overcome by adjusting the back suction pressure of the liquid. For example, when printing with a ceramic needle with an outer diameter of 700μm and an inner diameter of 600μm and a back suction pressure of 3psi, the output becomes discontinuous when the printhead speed is increased to 400mm / s. When the back suction pressure is reduced to 2.5psi, the discontinuity disappears. Although this method of adjusting the back suction pressure is feasible, the operation is relatively cumbersome.

[0004] Furthermore, this printing method produces a very fine material jet, resulting in low efficiency and low printing accuracy. Summary of the Invention

[0005] To address the aforementioned technical problems, the inventors of this application analyzed the current situation where printing efficiency could not be further improved in the prior art, sought the causes of the technical problems, and further designed and improved the method for forming thin film patterns, so as to further improve printing efficiency while ensuring printing accuracy. The purpose of this invention is to provide a method for forming thin film patterns.

[0006] The specific technical solutions are explained below:

[0007] A method for forming a thin film pattern includes the following steps:

[0008] (S.1): The step of stabilizing the liquid in the discharge needle at the discharge port under negative pressure;

[0009] Thin film material preparation typically uses low-viscosity liquids. When the liquid is stationary in the dispensing needle, it is affected by gravity, internal wall resistance, and surface tension. Gravity and surface tension are downward, while internal wall resistance is upward. Gravity is much stronger than the other two forces, causing the liquid to flow out of the dispensing needle uncontrollably. This is an unstable state, making film formation impossible. In this case, a negative pressure device needs to be installed to counteract the effect of gravity with the suction force of the negative pressure, so that the liquid at the dispensing nozzle is in a stable state where it is about to flow out.

[0010] (S.2): The step of forming a potential difference between the discharge needle and the substrate, causing the liquid to form a Taylor cone toward the surface of the substrate;

[0011] (S.3): The step of bringing the tip of the Taylor cone into contact with the surface of the substrate and moving the discharge needle to draw a pattern;

[0012] To precisely control the amount of liquid left on the substrate, an electric field device is needed. When the outlet is at a certain height from the substrate in the above stable state, the liquid will not be affected by the surface tension of the substrate and will not be actively discharged. After a high voltage electric field is applied between the outlet and the substrate, the liquid in the discharge needle is polarized and gradually forms a Taylor cone under the action of the electric field. During the formation of the Taylor cone, the liquid contacts the substrate. Then, the surface tension of the liquid on the substrate is the main driving force to pull the liquid evenly from the discharge needle onto the substrate. Therefore, in step (S.3), the output power of the liquid includes the surface tension between the substrate and the liquid.

[0013] In the aforementioned technical solution, the inventors employed a novel material discharge method. This method does not primarily rely on air pressure, mechanical pressure, or even voltage to extrude the liquid material. Instead, it utilizes the surface tension of the liquid material on the substrate surface as the main driving force to achieve the discharge process. Specifically, when the discharge port moves relative to the substrate, the liquid material continuously wets the substrate through surface tension, thereby achieving discharge. This discharge method has certain advantages. First, the surface tension discharge method is more stable and controllable, allowing for better control of the material's flow rate and volume, thus achieving more precise printing results. Second, the surface tension discharge method can achieve finer printing precision. Because the material wets the substrate through surface tension, a thinner liquid layer can be formed without additional overflow. This is highly beneficial for applications requiring high-precision pattern printing.

[0014] Preferably, the process of forming multiple lines / partial patterns also includes the step of repeating steps (S.1) to (S.3) to draw the pattern again.

[0015] Substrate surface properties play a crucial role in material adhesion and the smoothing of printed pattern edges. The following is a description of substrate properties that facilitate liquid adhesion and edge smoothing:

[0016] 1. Polar surfaces: Substrate surfaces with high polarity, such as glass and metals, can attract liquid molecules. This adsorption allows the liquid to form a uniform thin layer on the substrate surface and helps maintain smooth liquid edges;

[0017] 2. High surface energy: The substrate surface with high surface energy provides better interfacial bonding ability, which can enhance the interaction between the film and the substrate, and improve the adhesion and stability of the film;

[0018] 3. Smooth Surface: The smaller the roughness of the substrate, the more uniform the liquid adhesion and the smoother the edges. A smooth surface can reduce the irregular distribution of liquid on the substrate, making the liquid edges more regular.

[0019] Preferably, before drawing the pattern, the method further includes a step of surface treatment of the substrate: immersing the substrate in a solvent, wiping the surface of the substrate, and then performing plasma surface cleaning after removing it.

[0020] Preferably, the viscosity of the liquid is less than 500 cp.

[0021] More preferably, the inner diameter of the discharge port is 150~800μm and the outer diameter is 300~2300μm. During the material discharge process, the inner diameter of the discharge port is closely related to the flow rate of the material. The smaller the inner diameter, the smaller the flow rate. The outer diameter of the discharge port is related to the printed line width. This is because, under the action of surface tension between the substrate and the material, the Taylor cone formed will spread out on the surface of the discharge port after contacting the substrate.

[0022] More preferably, the vacuum degree of the negative pressure is 0.5~4.5 kPa, which is sufficient to stabilize the liquid.

[0023] More preferably, the potential difference is 500V~1800V. If the potential difference is too small, the liquid material cannot be pulled to form a Taylor cone. If the potential difference is too large, the liquid material is easy to detach from the Taylor cone and spray out, thus failing to achieve the printing effect expected by the invention.

[0024] Preferably, to enhance control over the flow velocity of low-viscosity liquids within the nozzle, the liquid flows through a narrowed section within the discharge needle before reaching the discharge port. The inner diameter of the narrowed section is smaller than the inner diameter of the discharge port, thus limiting the flow of the liquid by reducing the orifice diameter. This method of enhancing flow channel resistance has the following advantages: First, by reducing the orifice diameter of the inner tube, the resistance of the liquid material within the flow channel is increased. When the liquid flows through a smaller orifice, the interaction force between liquid molecules increases due to the reduced channel size, making fluid flow more difficult. This effectively slows down the liquid flow rate and improves the control over low-viscosity liquids. By enhancing flow channel resistance, we can achieve more precise printing results. In traditional nozzles, low-viscosity liquids often flow too quickly, leading to inaccurate printing results. However, by using a narrowed section with a smaller inner diameter in a larger discharge needle, we can achieve more precise printing results without changing the discharge port diameter—i.e., the actual printing width.

[0025] In the technical solution of this application, since the viscosity of the liquid material is low, it is more suitable to choose a precision ceramic material with lower surface roughness for the outlet. The actual printed line width is affected by the nozzle outer diameter, and the liquid material is more likely to spread to the side wall of the outlet under the action of surface tension, resulting in an increase in the outer diameter of the outlet and thus a decrease in printing accuracy. Therefore, preferably, a pretreatment step is also included: the outlet of the outlet of the outlet is cleaned with oxygen plasma, then immersed in a hydrophobic agent, and then baked after removal. Through this process, a hydrophobic layer is formed on the surface of the outlet, improving the adhesion of the liquid material to the surface. The hydrophobic agent used is preferably a solution system of alkoxysilane and alcohol.

[0026] However, the hydrophobic layer can only maintain a semi-permanent state; prolonged immersion in organic solvents will cause the hydrophobic layer to degrade. Therefore, a further preferred method includes a step of cleaning the dispensing needle. When a certain amount of material accumulates at the dispensing port, it is moved to a cleaning tank and cleaned using a nano-sponge, which can be dry or impregnated with organic cleaning solvent. After cleaning, the dispensing needle needs to be moved to the adhesive application station. The adhesive application and wiping are performed together. Using an adhesive application mechanism equipped with a dripping device, the adhesive cloth is first moistened with the hydrophobic agent, and then the wiping action is performed.

[0027] Preferably, the distance between the discharge port and the surface of the substrate is greater than 10 μm.

[0028] Preferably, in step (S.3), the moving speed of the ejector needle when drawing the pattern is 0~500mm / s. The technical solution of this application can still ensure printing quality when the moving speed of the ejector needle exceeds 300mm / s.

[0029] Preferably, before step (S.3), the pattern drawing path should be set. By optimizing the design of the printing path, we can better control the wetting process of the liquid material and achieve a more accurate printing effect.

[0030] Preferably, the setting of the pattern drawing path includes the step of preventing repeated drawing at the intersection of lines;

[0031] At the intersection, only one line contacts the substrate surface during drawing, while the remaining lines are prevented from leaking ink. More preferably, during pattern drawing, a gap is left between the remaining lines and the intersection, with the minimum gap being 1.5 to 2.5% of the printed line width.

[0032] The above pattern drawing method focuses on drawing efficiency. It does not avoid the intersections and relies on the material properties to form the pattern naturally. The gaps left during pattern printing will be filled by the attraction between molecules after the liquid flows level.

[0033] Preferably, the setting of the pattern drawing path includes the step of the discharge needle entering outside the substrate and drawing the pattern;

[0034] After the liquid material enters the substrate through the discharge needle, it forms the Taylor cone under the action of the potential difference to draw the pattern.

[0035] After the discharge needle moves out of the range of the substrate, the liquid loses the effect of the potential difference and stops discharging.

[0036] The above pattern drawing method abandons the vertical movement of the ejector needle. First, the electric field is turned on, and the horizontal movement starts from the starting point of the extended part of the drawing path. When cutting into the substrate, the material inside the nozzle is polarized after the electric field is turned on and a high voltage electric field is applied between the ejector needle and the substrate. Under the action of the electric field force, a Taylor cone is gradually formed. During the formation of the Taylor cone, the material contacts the substrate, forming an electric field-assisted ejection printing state.

[0037] Preferably, the setting of the pattern drawing path includes the step of drawing multiple sub-lines and splicing them together to form the target line width of the pattern. More preferably, during pattern drawing, the spacing L between the sub-lines is: ;

[0038] In the formula: RL is the target line width, and MR is the length of the smooth curve at the edge of the sub-line.

[0039] To improve the accuracy of pattern drawing, it is advisable to use a smaller diameter nozzle. In numerous experiments, different nozzle diameters were tested. We found that the actual line width fluctuation is usually 1.5% of the set line width. It is easy to conclude that using a smaller diameter nozzle to print multiple lines and splice them to the target line width can improve the accuracy of pattern drawing. To avoid increasing printing time too much, it is preferable to splice 3 lines. In the experiments, the inventors also found that the appropriate line spacing has a crucial impact on the flatness of the pattern. If the line spacing is too large, the liquid cannot flow evenly, and there will be obvious depressions in the middle of the lines. If the line spacing is too small, the liquid will accumulate on the previous liquid material, resulting in an excessively thick pattern. Therefore, the inventors obtained a reasonable value through continuous experimentation to make the liquid film surface flat. Finally, a flat film surface can be obtained by using a reasonable line spacing.

[0040] In summary, the technical solution described in this invention has the following main beneficial effects:

[0041] Compared with existing technologies, the technical solution of this application can increase the moving speed of the discharge needle to 500mm / s, which greatly improves the working efficiency while still ensuring a good film pattern formation effect.

[0042] Furthermore, printing accuracy can be further improved by setting the printing method.

[0043] Meanwhile, the thickness of thin film printing can be less than 1 micrometer, and the flatness is relatively high.

[0044] More importantly, this method for forming thin film patterns has advantages in terms of initial investment. Compared to traditional technologies, it requires less upfront investment, including lower costs for equipment purchase, maintenance, and template preparation. This will help reduce project risk and improve return on investment.

[0045] This method of forming thin film patterns is more economical in terms of equipment costs. Compared to other technologies that require complex and expensive equipment, the required equipment cost is relatively low. This will help alleviate the financial burden on enterprises and make the cost of using this technology affordable for more businesses.

[0046] The method for forming this thin film pattern has relatively low process complexity. It employs a simple process flow, eliminating the need for template preparation and thin film masking, making the technical operation simpler and more efficient. This will help improve production efficiency and reduce the difficulty of technical operations.

[0047] Further or more detailed beneficial effects will be described in conjunction with specific embodiments in the detailed implementation. Attached Figure Description

[0048] Figure 1This is a schematic diagram of the step-by-step printing path using solid horizontal lines and dashed vertical lines in Example 1;

[0049] Figure 2 This is a schematic diagram of the printing path for edge cutting in Example 2;

[0050] Figure 3 This is a schematic diagram of the printing path of the three segments of the small nozzle in Example 3, where the shaded area is the overlapping area of ​​the printing;

[0051] Figure 4 This is a schematic diagram of the splicing morphology of a single line segment in Example 3;

[0052] Figure 5 This is a schematic diagram showing the morphology of the liquid material in the Taylor cone state and the drawn state. Detailed Implementation

[0053] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0054] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0055] Unless otherwise expressly specified and limited, the terms "connection," "fixed," and "set" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0056] The core technical problem faced by the technical solution of this application's embodiments stems from the inventor's in-depth understanding of the technical problems in the prior art.

[0057] Therefore, based on a deep understanding of the technical problems, how to further improve printing efficiency is a technical problem that the inventors urgently need to solve.

[0058] At the same time, improving printing accuracy is also a technical problem that the inventors are striving to solve simultaneously.

[0059] The specific implementation examples are detailed below:

[0060] Example 1: The back-side mesh light-shielding layer of the wafer is printed in steps, with solid lines horizontally and dashed lines vertically. The printing path is shown in the attached diagram. Figure 1 .

[0061] 1) Print path design and machine preparation:

[0062] ① Taking a mesh-like light-shielding layer on the back of a wafer with a horizontal line width of 955μm and a spacing of 4976μm, and a vertical line width of 758μm and a spacing of 6902μm as an example, design the printing route. The horizontal line is a complete long line and the vertical line is a short line. The vertical short line segments avoid the horizontal long lines. The printing line width is 2%. Write a motion control program based on the printing program.

[0063] ② Based on the required line width for printing, it is preferable to use precision ceramic nozzles with an outer diameter of 900μm and an inner diameter of 800μm, or with an outer diameter of 700μm and an inner diameter of 600μm;

[0064] ③ Install the precision ceramic nozzles into the machine tool fixtures respectively;

[0065] ④ Import the motion program into the matching CAM software, and set the following parameters in the software interface: suction pressure (2psi), workpiece Z-axis needle lifting height (200µm), printing height (30µm), running speed 200mm / s, voltage intensity 1000V, online surface treatment frequency (the nozzle is cleaned and the adhesive and hydrophobic agent are applied after each pc is printed).

[0066] ⑤ Clean the silicon substrate wafer using alcohol solvent.

[0067] 2) Feeding:

[0068] ① Select a suitable solution: black photolithography ink, viscosity 6 cps;

[0069] ② Connect the two cartridges containing black photolithography ink to the ends of the corresponding two nozzles;

[0070] ③ Place 1 pcs or 12-inch wafer on the workpiece suction cup of the equipment and turn on vacuum adsorption. The equipment will then perform a mechanical return to zero action.

[0071] 3) Pattern printing:

[0072] ① Visually captures the silicon wafer mark points, calculates the workpiece deflection angle based on the mark information, and then straightens the workpiece using a DD motor;

[0073] ② Use a laser displacement sensor to scan the entire wafer light-shielding layer printing area, and CAM software to record the height and undulation data of the workpiece surface;

[0074] ③ Use a laser displacement sensor to measure the height of the dispensing starting point, and then perform the first online surface treatment of the nozzle;

[0075] ④ Move the sample stage to move the nozzle to the starting position of the printing program (based on the first nozzle on the left).

[0076] ⑤ Lower the nozzle with an outer diameter of 900μm and an inner diameter of 800μm to a position 30μm above the substrate (i.e., the height at which the droplet forms a printing state that can be pulled by the electric field force at the nozzle).

[0077] ⑥ When the electric field is turned on, the liquid material is pulled to the substrate to form a stable state, and the workpiece begins to move in the XY direction;

[0078] ⑦ The XY axes move along the path programmed in the motion program. When they reach the end of the line segment, the electric field turns off, the print head lifts up, and the printing of a single line segment stops.

[0079] ⑧ Repeat steps ⑤, ⑥, and ⑦ to print all horizontal line segments;

[0080] ⑨ Repeat steps ④, ⑤, ⑥, ⑦, and ⑧ using a nozzle with an outer diameter of 700 μm and an inner diameter of 600 μm to complete all longitudinal line segments;

[0081] ⑩ After printing a single wafer is completed, printing is paused, the nozzle is automatically lifted, and it moves to the cleaning tank and the adhesive application and hydrophobic agent application station for surface treatment.

[0082] ⑪ Move the nozzle to a safe position in the Z-axis direction, stop the Z-axis movement of the workpiece, and turn off the vacuum adsorption to remove the workpiece.

[0083] Example 2: Edge-cut printing, printing path reference attached. Figure 2 .

[0084] 1) Dot matrix design and machine preparation:

[0085] ① Taking a mesh-like light-shielding layer on the back of a wafer with a horizontal line width of 955μm and a spacing of 4976μm, and a vertical line width of 758μm and a spacing of 6902μm as an example, design the printing route, with the horizontal line being a complete long line and the vertical line being a short line, and write a motion control program based on the printing program;

[0086] ② Based on the required line width for printing, it is preferable to use precision ceramic nozzles with an outer diameter of 900μm and an inner diameter of 800μm, or with an outer diameter of 700μm and an inner diameter of 600μm;

[0087] ③ Install the precision ceramic nozzles into the machine tool fixtures respectively;

[0088] ④ Import the motion program into the matching CAM software, and set the following parameters in the software interface: suction pressure (1.65 psi), workpiece Z-axis lifting needle (200 μm), printing height (30 μm), running speed 200 mm / s, voltage intensity 1000 V, online surface treatment frequency (cleaning the printing nozzle and applying hydrophobic agent once per pc).

[0089] 2) Feeding:

[0090] ① Select a suitable liquid material: black photolithography ink, viscosity 6 cps;

[0091] ② Connect the two cartridges containing black photolithography ink to the ends of the corresponding two nozzles;

[0092] ③ Place 1 pcs or 12-inch silicon wafer on the workpiece suction cup of the equipment and turn on vacuum adsorption. The equipment will then perform a mechanical return to zero action.

[0093] 3) Pattern printing:

[0094] ① Visually captures the silicon wafer mark points, calculates the workpiece deflection angle based on the mark information, and then straightens the workpiece using a DD motor;

[0095] ② Use a laser displacement sensor to scan the entire wafer light-shielding layer printing area, and CAM software to record the height and undulation data of the workpiece surface;

[0096] ③ Use a laser displacement sensor to measure the height of the dispensing starting point, and then perform the first online surface treatment of the nozzle;

[0097] ④ Move the sample stage to move the nozzle to the starting position of the printing program (the printing path is designed to be outside the wafer and 100μm from the actual printed line segment extension).

[0098] ⑤ Lower the nozzle with an outer diameter of 900μm and an inner diameter of 800μm to a position 30μm above the substrate (i.e., the height at which the droplet forms a printing state that can be pulled by the electric field force at the nozzle).

[0099] ⑥ When the electric field is turned on, the liquid material is pulled to the substrate to form a stable state, and the workpiece begins to move in the XY direction;

[0100] ⑦ Move along the X-axis according to the path written in the motion program. When it reaches the end of a single printing path, move along the Y-axis to the next printing path until all 955μm line segments are printed.

[0101] ⑧ Raise the nozzle with an outer diameter of 900μm and an inner diameter of 800μm to a safe position;

[0102] ⑨ Repeat steps ④, ⑤, ⑥, ⑦ (printing in the Y direction and moving the line segment interval in the X direction) and ⑧ using a nozzle with an outer diameter of 700μm and an inner diameter of 600μm to complete all 758μm line segments;

[0103] ⑩ After printing a single wafer is completed, printing is paused, the nozzles are automatically lifted, and the two nozzles move sequentially to the cleaning tank and the adhesive application and hydrophobic agent application station for surface treatment;

[0104] ⑪ Move the nozzle to the safe position in the Z direction, stop the Z-axis movement of the workpiece, move the XY axis to the upper and lower workpiece positions, turn off the vacuum adsorption and remove the workpiece.

[0105] Example 3: Three-segment printing with a small nozzle; printing path reference attached. Figure 3 .

[0106] Dot matrix design and machine preparation:

[0107] ① Taking a mesh-like light-shielding layer on the back of a wafer with a horizontal line width of 955μm and a spacing of 4976μm, and a vertical line width of 758μm and a spacing of 6902μm as an example, design the printing route. The horizontal line is a complete long line and the vertical line is a short line. The short vertical line segments avoid the horizontal long lines. The single printing line width is 2%. Write a motion control program based on the printing program.

[0108] ② Based on the required line width for printing, it is preferable to use precision ceramic nozzles with an outer diameter of 300μm and an inner diameter of 200μm, or with an outer diameter of 300μm and an inner diameter of 150μm.

[0109] ③ Install the precision ceramic nozzles into the machine tool fixtures respectively;

[0110] ④ Import the motion program into the matching CAM software, and set the following parameters in the software interface: suction pressure (2psi), workpiece Z-axis high-frequency short-distance reciprocating motion distance (200µm), dispensing height (30µm), running speed 200mm / s, electric field strength 1000V, online surface treatment frequency (cleaning and applying hydrophobic agent to the printing nozzle once per pc).

[0111] 2) Feeding:

[0112] ① Select a suitable liquid material: black photolithography ink, viscosity 6 cps;

[0113] ② Connect the two cartridges containing black photolithography ink to the ends of the corresponding two nozzles;

[0114] ③ Place 1 pcs or 12-inch silicon wafer on the workpiece suction cup of the equipment and turn on vacuum adsorption. The equipment will then perform a mechanical return to zero action.

[0115] 3) Pattern printing:

[0116] ① Visually captures the silicon wafer mark points, calculates the workpiece deflection angle based on the mark information, and then straightens the workpiece using a DD motor;

[0117] ② Use a laser displacement sensor to scan the entire wafer light-shielding layer printing area, and CAM software to record the height and undulation data of the workpiece surface;

[0118] ③ Use a laser displacement sensor to measure the height of the dispensing starting point, and then perform the first online surface treatment of the nozzle;

[0119] ④ Move the sample stage to move the nozzle to the starting position of the printing program (based on the first nozzle on the left).

[0120] ⑤ Lower the nozzle with an outer diameter of 300μm and an inner diameter of 200μm to a position 30μm above the substrate (i.e., the height at which the droplet is formed and printed by the electric field force).

[0121] ⑥ When the electric field is turned on, the liquid material is pulled to the substrate to form a stable state, and the workpiece begins to move in the XY direction;

[0122] ⑦ The X and Y axes move along the path programmed in the motion program. When they reach the end of the line segment, the electric field turns off, the print head lifts, and printing of a single line segment stops. Refer to the appendix for the printed appearance of a single line segment. Figure 4 (A single line segment consists of three round trips, with the distance between each trip designed as L, where L is:) ;

[0123] In the formula: RL is the target line width, and MR is the length of the smooth curve at the edge of the sub-line).

[0124] ⑧ Repeat steps ⑤, ⑥, and ⑦ to print all horizontal line segments;

[0125] ⑨ Repeat steps ④, ⑤, ⑥, ⑦, and ⑧ using a nozzle with an outer diameter of 700 μm and an inner diameter of 600 μm to complete all longitudinal line segments;

[0126] ⑩ After printing a single wafer is completed, printing is paused, the nozzle is automatically lifted, and it moves to the cleaning tank and the adhesive application and hydrophobic agent application station for surface treatment.

[0127] ⑪ Move the nozzle to a safe position in the Z-axis direction, stop the Z-axis movement of the workpiece, and turn off the vacuum adsorption to remove the workpiece.

[0128] For schematic diagrams of the material liquid transitioning from the Taylor cone state to the pattern-drawing state in Examples 1-3, please refer to the attached diagram. Figure 5 .

[0129] The film-forming performance parameters of Examples 1-3 are shown in Table 1 below:

[0130] Table 1 Film-forming properties of Examples 1-3

[0131]

[0132] As can be seen from Table 1, Examples 1-3 can all obtain thin film patterns with flat film thickness and high printing accuracy.

[0133] Based on Example 1:

[0134] The film-forming performance parameters obtained by simply changing the viscosity of the feed solution are shown in Table 2 below:

[0135] Table 2 Effect of feed viscosity on film-forming properties

[0136]

[0137] The vacuum level of the negative pressure is changed during feeding, and the state of the liquid material is shown in Table 3 below:

[0138] Table 3. Effect of vacuum degree during feeding on the state of the finished liquid.

[0139]

[0140] The film formation performance parameters obtained by changing only the voltage intensity are shown in Table 4 below:

[0141] Table 4 Effect of voltage intensity on film formation performance

[0142]

[0143] The film formation performance parameters obtained by changing only the nozzle operating speed are shown in Table 5 below:

[0144] Table 5. Effect of nozzle operating speed on film formation performance

[0145]

[0146] As shown in Tables 2-5, all methods within the above parameter range can obtain thin film patterns with smooth film thickness and high printing accuracy.

[0147] Comparative Example 1:

[0148] The difference from Example 1 is that the dispensing valve is used to control the material output by air pressure, which makes it difficult to control the flow rate of low-viscosity liquid materials. Table 6 below shows the dispensing situation of black photoresist with a viscosity of 6 cps:

[0149] Table 6: Relationship between air pressure and material discharge in Comparative Example 1

[0150]

[0151] As shown in Table 6, when the liquid material is driven solely by air pressure, the liquid material is prone to uncontrolled large-scale discharge within a small range of air pressure fluctuations, which in turn affects the pattern formation effect.

[0152] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0153] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

[0154] The above embodiments are for illustrating the implementation schemes disclosed in this invention and should not be construed as limiting the invention. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the invention, will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been specifically described in conjunction with various specific preferred embodiments, it should be understood that the invention should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included within the scope of this invention.

Claims

1. A method for forming a thin film pattern, characterized in that, Includes the following steps: Before drawing the pattern, the process includes a step of performing a plasma surface treatment on the substrate; (S.1): The step of stabilizing the liquid in the discharge needle at the discharge port under negative pressure; (S.2): The step of forming a potential difference between the discharge needle and the substrate, causing the liquid to form a Taylor cone toward the surface of the substrate; (S.3): The step of bringing the tip of the Taylor cone into contact with the surface of the substrate and moving the discharge needle to draw a pattern; in this step, the electric field is turned on, the liquid material is pulled to the substrate to begin to form a stable state, and the workpiece begins to move in the XY direction; In step (S.3), the output power of the liquid includes the surface tension between the substrate and the liquid. During the formation of the Taylor cone, the liquid contacts the substrate, and then the surface tension of the liquid on the substrate is the main driving force to evenly pull the liquid from the dispensing needle onto the substrate.

2. The thin film pattern forming method according to claim 1, characterized in that: It also includes the step of repeating steps (S.1) to (S.3) to draw the pattern again.

3. The thin film pattern forming method according to claim 1 or 2, characterized in that: The viscosity of the liquid is less than 500 cp.

4. The thin film patterning method according to claim 3, characterized in that: The vacuum degree of the negative pressure is 0.5~4.5psi.

5. The thin film patterning method according to claim 4, characterized in that: The potential difference is 500V~1800V.

6. The thin film patterning method according to claim 1, characterized in that: It also includes a pretreatment step for the discharge needle: the discharge port of the discharge needle is cleaned with oxygen plasma, then immersed in a hydrophobic agent, and then taken out and baked.

7. The thin film patterning method according to claim 1, characterized in that: The distance between the discharge port and the surface of the substrate is greater than 10 μm.

8. The thin film patterning method according to claim 1, characterized in that: Before step (S.3), the pattern drawing path must be set.

9. The thin film patterning method according to claim 5, characterized in that: The setting of the pattern drawing path includes the step of preventing repeated drawing at the intersection of lines; At the intersection, only one line is drawn with liquid in contact with the surface of the substrate, while the remaining lines are drawn to prevent liquid from being discharged.

10. The thin film patterning method according to claim 9, characterized in that: When drawing the pattern, a gap is left between the remaining lines and the intersection, and the minimum value of the gap is 1.5 to 2.5% of the printed line width.

11. The thin film patterning method according to claim 8, characterized in that: The setting of the pattern drawing path includes the step of the discharge needle entering outside the substrate and drawing the pattern; After the liquid material enters the substrate through the discharge needle, it forms the Taylor cone under the action of the potential difference to draw the pattern. After the discharge needle moves out of the range of the substrate, the liquid loses the effect of the potential difference and stops discharging.

12. The thin film patterning method according to claim 8, characterized in that: The setting of the pattern drawing path includes the step of drawing multiple sub-lines to splice together the target line width of the pattern.

13. The thin film patterning method according to claim 12, characterized in that: When drawing the pattern, the spacing L between the sub-lines is: ; In the formula: RL is the target line width, and MR is the length of the smooth curve at the edge of the sub-line.

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