Spacing automatic control structure and method for laser direct writing photoetching

Abstract

The invention provides an automatic spacing control structure for laser direct writing lithography, and relates to the technical field of lithography machines.The automatic spacing control structure comprises a lithography machine frame, a nozzle, an air pressure stabilizer and a correction unit, the correction unit provides a control group for spacing measurement, firstly, the gas consumption of the correction unit is measured in a calibration environment and an actual working condition respectively, and the gas consumption of the correction unit is calculated; the distance between the nozzle and the mask plate under the actual working condition can be further determined by determining the relation between the distance between the nozzle and the mask plate under the calibration environment and the gas consumption due to the fact that the distance between the nozzle and the mask plate and the gas consumption are in the linear relation, and therefore the distance between the nozzle and the mask plate under the actual working condition can be determined. The actual distance is compared with the deviation threshold value, when the actual distance exceeds the deviation threshold value, the piezoelectric ceramic is slightly deformed by adjusting the voltage of the piezoelectric ceramic to compensate the distance deviation, the distance between the nozzle and the mask plate is constant, and due to the fact that the correction unit serves as a reference, the calculation precision is high, and the deviation is small.

Description

Technical Field

[0001] The present invention relates to the technical field of photolithography machines, and in particular to an automatic spacing control structure and method for laser direct writing photolithography. Background Art

[0002] Laser direct writing lithography is a high-precision technology used for micro-nano processing, and is widely used in semiconductors, optoelectronics, micro-electromechanical systems and other fields. During the etching process of the mask, the distance between the laser direct writing lithography head and the mask must remain constant. The distance between the lithography head and the mask is usually measured by non-contact methods, such as gas flow method, laser interferometry method, capacitance method, etc., and the gas flow method is currently the main one. The advantages of this method are simple measurement principle, high precision, no effect on the mask morphology, and low cost.

[0003] However, its disadvantage is that it is affected by gas pressure and ambient temperature, which makes the automatic control spacing calculation complicated and prone to errors, resulting in poor accuracy.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The object of the present invention is to provide a spacing automatic control structure and method for laser direct writing lithography to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A spacing automatic control structure for laser direct writing lithography, comprising a lithography machine frame, a nozzle, a gas pressure stabilizer and a correction unit:

[0008] The nozzle is mounted on the photolithography machine frame through piezoelectric ceramics;

[0009] Flow meters are installed at two output ends of the air pressure stabilizer, and one of the output ends of the flow meter is connected to the correction unit, and the other flow meter is connected to the nozzle. The air pressure stabilizer is used to provide a stable airflow;

[0010] The correction unit includes a correction nozzle, a correction baffle, a pressure cylinder and a pipe joint, the air inlet end of the pipe joint is connected to the flow meter, the exhaust end of the pipe joint is connected to the correction nozzle, the air path in the correction nozzle is the same as the air path of the nozzle, the pressure cylinder is installed on the correction nozzle, and the correction baffle is arranged inside the pressure cylinder.

[0011] Furthermore, a sliding table is installed on the photolithography machine frame, and a mask is installed on the sliding table.

[0012] Furthermore, the upper surface of the correction baffle is a flat plane.

[0013] Furthermore, the outer side wall of the correction nozzle is provided with an external thread, the inner side wall of the pressure cylinder is provided with an internal thread, and the pressure cylinder is threadedly connected to the correction nozzle.

[0014] The present invention also provides a spacing automatic control method for laser direct writing lithography, using a spacing automatic control structure for laser direct writing lithography, and the specific steps include:

[0015] S1. A step with a height of h is processed on the correction nozzle 41. The pressing cylinder 43 is screwed into the correction nozzle 41 and the correction baffle 42 is fitted with the step of the correction nozzle 41 to ensure that the spacing of the correction unit is fixed at h;

[0016] S2, start the photolithography machine and the air pressure stabilizer 6 respectively under the calibration environment and the actual working condition, and the air pressure stabilizer 6 provides constant pressure gas with the same air pressure and flow rate to the two flow meters 5 respectively;

[0017] S3. Under the calibration environment, one of the flow meters 5 is used to measure the gas consumption G0 of the correction nozzle 41 and the correction baffle 42. Under the actual working condition, the flow meter 5 is used to measure the gas consumption G1 of the correction nozzle 41 and the correction baffle 42, and the gas consumption G0 and the gas consumption G1 are pre-processed to generate the correction coefficient K. c , correction factor K c Used to compensate for the effects of gas supply pressure, temperature, etc. on spacing measurement;

[0018] S4. Under actual working conditions, measure the nozzle gas consumption G2, and the gas consumption G2 and correction factor K c Perform preprocessing to generate the actual distance S between the nozzle and the mask under actual working conditions;

[0019] S5. Compare the actual spacing S with the deviation threshold. When the actual spacing S exceeds the deviation threshold, adjust the piezoelectric ceramic voltage to cause the piezoelectric ceramic to deform slightly to compensate for the spacing deviation, so that the spacing between the nozzle and the mask is constant.

[0020] Furthermore, in S2, the gas consumption G0 and the gas consumption G1 are preprocessed to generate a correction coefficient K c , the formula used is: Among them, K c It is a correction factor used to compensate for the influence of gas supply pressure, temperature, etc. on spacing measurement.

[0021] Furthermore, according to the fluid mechanics formula: Where C1 is the nozzle baffle flow coefficient, ε is the air expansion coefficient, d is the nozzle air path diameter, g is the gravity acceleration, h t is the spacing of the nozzle mask, P c is the gas pressure, γc is the air density, G is the gas consumption of the nozzle, the actual working condition measurement deviation b is set, and the proportional coefficient k is set. Under the calibration environment, both are fixed values. By transforming the above formula, we can know the spacing-gas consumption formula: h t =k*G+b, where b is the actual working condition measurement deviation, and the gas consumption G and the nozzle mask spacing h under the calibration environment are collected. t Data set, generate values ​​of k and b by least squares fitting;

[0022] Spacing-gas consumption formula, correction factor K c , gas consumption G2 is correlated to generate the actual spacing S. The formula used is:

[0023] S=k* K *G2+b

[0024] Furthermore, the calibration environment is at normal temperature and pressure.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a correction unit, which provides a control group for spacing measurement. The spacing between the nozzle and the mask plate and the gas consumption are in a linear relationship. First, the gas consumption of the correction unit is measured in a calibration environment and in actual working conditions, and the ratio thereof is set as a correction coefficient. Since the spacing between the nozzle and the mask plate and the gas consumption are in a linear relationship, the correction coefficient can eliminate the influence of temperature and pressure on the actual spacing in actual working conditions. Further, the spacing between the nozzle and the mask plate in actual working conditions can be determined by determining the relationship between the spacing between the nozzle and the mask plate in the calibration environment and the gas consumption. The actual spacing is compared with a deviation threshold. When the actual spacing exceeds the deviation threshold, the piezoelectric ceramic voltage is adjusted to cause the piezoelectric ceramic to produce a slight deformation to compensate for the spacing deviation, so that the spacing between the nozzle and the mask plate is constant. Since there is a correction unit as a reference, the calculation accuracy is high and the deviation is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the automatic spacing control structure of the laser direct writing lithography of the present invention;

[0028] Figure 2 It is a structural schematic diagram of a correction unit of the automatic spacing control structure of laser direct writing lithography of the present invention.

[0029] Figure numerals: 1. frame; 2. piezoelectric ceramic; 3. nozzle; 4. correction unit; 5. flow meter; 6. constant pressure gas source 7. mask; 41. correction nozzle; 42. correction baffle; 43. pressure cylinder; 44. pipe joint. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0031] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] Example:

[0033] See also Figure 1 and Figure 2 , the present invention provides a technical solution:

[0034] An automatic spacing control structure for laser direct writing lithography includes a lithography machine frame 1, a nozzle 3, a gas pressure stabilizer 6 and a correction unit 4. Laser can pass through the middle of the nozzle 3 to etch a mask. The gas pressure stabilizer 6 is used to provide a stable and constant airflow. The correction unit 4 is used to provide a control unit for the laser direct writing lithography machine under actual working conditions, and is used to compensate for the influence of gas pressure and temperature on the spacing of the laser direct writing lithography machine.

[0035] The nozzle 3 is mounted on the photolithography machine frame 1 through the piezoelectric ceramic 2; the piezoelectric ceramic 2 can be deformed by adjusting the voltage, thereby adjusting the gap between the nozzle 3 and the mask.

[0036] The two output ends of the air pressure stabilizer 6 are respectively installed with flow meters 5, and the output end of one of the flow meters 5 is connected to the correction unit 4, and the other flow meter 5 is connected to the nozzle 3. The air pressure stabilizer 6 is used to provide a stable airflow;

[0037] The correction unit 4 includes a correction nozzle 41, a correction baffle 42, a pressure cylinder 43 and a pipe joint 44. The air inlet end of the pipe joint 44 is connected to the flow meter 5, and the exhaust end of the pipe joint 44 is connected to the correction nozzle 41. The air path in the correction nozzle 41 is the same as the air path of the nozzle 3 and is used to control the variable. The pressure cylinder 43 is installed on the correction nozzle 41, and the correction baffle 42 is arranged inside the pressure cylinder 43. A step of a fixed height is processed on the correction nozzle 41 and an external thread is arranged on the outer wall. An internal thread is arranged on the inner wall of the pressure cylinder 43. The pressure cylinder 43 is threadedly connected to the correction nozzle 41, and the correction baffle 42 is fitted with the step on the correction nozzle 41. The height of the step on the correction nozzle 41 ensures that the distance between the baffle 42 and the correction nozzle 41 is fixed.

[0038] Specifically, a sliding table is installed on the photolithography machine frame 1, and a mask plate 7 is installed on the sliding table.

[0039] Specifically, the upper surface of the correction baffle 42 is a flat plane, thereby reducing measurement errors.

[0040] The present invention provides a spacing automatic control method for laser direct writing lithography, using a spacing automatic control structure for laser direct writing lithography. According to the fluid mechanics formula, it can be known that: Therefore, the distance between the nozzle 3 and the mask plate and the gas consumption are in a linear relationship. The present invention first measures the gas consumption of the correction unit 4 under the calibration environment and under the actual working condition, and sets the ratio as the correction coefficient. Since the distance between the nozzle 3 and the mask plate and the gas consumption are in a linear relationship, the correction coefficient can eliminate the influence of temperature and pressure on the actual distance under the actual working condition. Further, by determining the relationship between the distance between the nozzle 3 and the mask plate and the gas consumption under the calibration environment, the distance between the nozzle 3 and the mask plate under the actual working condition can be determined. The specific steps include:

[0041] S1. A step with a height of h is processed on the correction nozzle 41. The pressing cylinder 43 is screwed into the correction nozzle 41 and the correction baffle 42 is fitted with the step of the correction nozzle 41 to ensure that the spacing of the correction unit is fixed at h;

[0042] S2, start the photolithography machine and the air pressure stabilizer 6 respectively under the calibration environment and the actual working condition, the air pressure stabilizer 6 provides constant pressure gas to the nozzle 3 and the correction nozzle 41 respectively, and the two flow meters 5 measure the gas consumption respectively;

[0043] S3. Under the calibration environment, one of the flow meters 5 is used to measure the gas consumption G0 of the correction nozzle 41 and the correction baffle 42. Under the actual working condition, the flow meter 5 is used to measure the gas consumption G1 of the correction nozzle 41 and the correction baffle 42, and the gas consumption G0 and the gas consumption G1 are pre-processed to generate the correction coefficient K. c , correction factor K cUsed to compensate for the effects of gas supply pressure, temperature, etc. on spacing measurement;

[0044] S4. Under actual working conditions, measure the gas consumption G2 of nozzle 3, and compare the gas consumption G2 and the correction factor K. c Perform preprocessing to generate an actual distance S between the nozzle 3 and the mask plate under actual working conditions;

[0045] S5. Compare the actual spacing S with the deviation threshold. When the actual spacing S exceeds the deviation threshold, adjust the voltage of the piezoelectric ceramic 2 to make the piezoelectric ceramic produce a slight deformation to compensate for the spacing deviation, so that the spacing between the nozzle 3 and the mask is constant.

[0046] Specifically, in S2, the gas consumption G0 and the gas consumption G1 are preprocessed to generate a correction coefficient K c , the formula used is: Among them, K c It is a correction factor used to compensate for the influence of gas supply pressure, temperature, etc. on spacing measurement.

[0047] Furthermore, according to the fluid mechanics formula: Where C1 is the nozzle baffle flow coefficient, ε is the air expansion coefficient, d is the nozzle air path diameter, g is the gravity acceleration, h t is the spacing of the nozzle mask, P c is the gas pressure, γ c is the air density, G is the air consumption of the nozzle, set the actual working condition measurement deviation b, set the proportional coefficient k, By transforming the above formula, we can know the spacing-gas consumption formula: h t =k*G+b, where b is the actual working condition measurement deviation, and the gas consumption G and the nozzle mask spacing h under the calibration environment are collected. t Data set, generate values ​​of k and b by least squares fitting;

[0048] Spacing-gas consumption formula, correction factor K c , gas consumption G2 is correlated to generate the actual spacing S. The formula used is:

[0049] S=k*K c **G2+b.

[0050] The actual spacing S is the spacing between the nozzle mask plates under actual working conditions, and the calibration environment is normal temperature and pressure.

[0051] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0052] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0053] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0054] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A spacing automatic control structure for laser direct writing lithography, comprising a lithography machine frame (1), a nozzle (3), an air pressure stabilizer (6) and a correction unit (4), characterized in that: The nozzle (3) is mounted on a photolithography machine frame (1) via a piezoelectric ceramic (2); Flow meters (5) are respectively installed at two output ends of the air pressure stabilizer (6), and one output end of the flow meter (5) is connected to the correction unit (4), and the other flow meter (5) is connected to the nozzle (3), and the air pressure stabilizer (6) is used to provide a stable airflow; The correction unit (4) comprises a correction nozzle (41), a correction baffle (42), a pressure cylinder (43) and a pipe joint (44); the air inlet end of the pipe joint (44) is connected to the flow meter (5); the air outlet end of the pipe joint (44) is connected to the correction nozzle (41); the air path in the correction nozzle (41) is the same as the air path of the nozzle (3); the pressure cylinder (43) is installed on the correction nozzle (41); and the correction baffle (42) is arranged inside the pressure cylinder (43).

2. The automatic spacing control structure for laser direct writing lithography according to claim 1, characterized in that: A sliding table is mounted on the photolithography machine frame (1), and a mask plate (7) is mounted on the sliding table.

3. The automatic spacing control structure for laser direct writing lithography according to claim 1, characterized in that: The upper surface of the correction baffle (42) is a flat plane.

4. The automatic spacing control structure for laser direct writing lithography according to claim 1, characterized in that: The outer wall of the correction nozzle (41) is provided with an external thread, the inner wall of the pressure cylinder (43) is provided with an internal thread, and the pressure cylinder (43) is threadedly connected to the correction nozzle (41).

5. A method for automatic spacing control in laser direct writing lithography, characterized in that: Using the automatic spacing control structure for laser direct writing lithography as described in claim 1, the specific steps include: S1. A step with a height of h is processed on the correction nozzle (41). The pressing cylinder (43) is screwed into the correction nozzle (41) and the correction baffle (42) is fitted with the step of the correction nozzle (41) to ensure that the spacing of the correction unit is fixed at h. S2, start the photolithography machine and the air pressure stabilizer 6 respectively under the calibration environment and the actual working condition, and the air pressure stabilizer 6 provides constant pressure gas with the same air pressure and flow rate to the two flow meters 5 respectively; S3. Under the calibration environment, one of the flow meters 5 is used to measure the gas consumption G0 of the correction nozzle 41 and the correction baffle 42. Under the actual working condition, the flow meter 5 is used to measure the gas consumption G1 of the correction nozzle 41 and the correction baffle 42, and the gas consumption G0 and the gas consumption G1 are pre-processed to generate the correction coefficient K. c , correction factor K c Used to compensate for the effects of gas supply pressure, temperature, etc. on spacing measurement; S4. Under actual working conditions, measure the gas consumption G2 of the nozzle (3), and compare the gas consumption G2 and the correction factor K. c Perform preprocessing to generate an actual distance S between the nozzle (3) and the mask plate under actual working conditions; S5, comparing the actual spacing S with the deviation threshold, and when the actual spacing S exceeds the deviation threshold, adjusting the voltage of the piezoelectric ceramic (2) to cause the piezoelectric ceramic to produce a slight deformation to compensate for the spacing deviation, so that the spacing between the nozzle (3) and the mask plate is constant.

6. The method for automatic spacing control for laser direct writing lithography according to claim 5, characterized in that: In S2, the gas consumption G0 and the gas consumption G1 are preprocessed to generate a correction coefficient K c , the formula used is: Among them, K c It is a correction factor used to compensate for the effects of gas supply pressure, temperature, etc. on spacing measurement.

7. The method for automatic spacing control for laser direct writing lithography according to claim 6, characterized in that: According to the fluid mechanics formula: Where C1 is the nozzle baffle flow coefficient, ε is the air expansion coefficient, d is the nozzle air path diameter, g is the gravity acceleration, h t is the spacing of the nozzle mask, P c is the gas pressure, γ c is the air density, G is the air consumption of the nozzle, set the actual working condition measurement deviation b, set the proportional coefficient k, By transforming the above formula, we can get the spacing-gas consumption formula: h t =k*G+b, where b is the actual working condition measurement deviation, and the gas consumption G and the nozzle mask spacing h under the calibration environment are collected. t Data set, generate values ​​of k and b by least squares fitting; Spacing-gas consumption formula, correction factor K c , gas consumption G2 is correlated to generate the actual spacing S. The formula used is: S=k*K c *G2+b。 8. The method for automatic spacing control for laser direct writing lithography according to claim 7, characterized in that: The calibration environment is normal temperature and pressure.

Images