Device and method for removing bubbles in liquid film layer

Abstract

The invention discloses a device for removing bubbles in a liquid film layer, which comprises a base for placing a substrate coated with the liquid film layer. The sealing cover is arranged above the base, a sealed space is formed above the base, and the substrate is located in the sealed space. And a cooling device and a vacuumizing device are arranged in the sealing cover. The cooling device is used for reducing the temperature of the sealed space so as to quickly freeze the liquid film layer. And the vacuumizing device is used for vacuumizing the sealed space after the liquid film layer is quickly frozen and degassing and removing bubbles in the liquid film layer. The invention further discloses a method for removing the bubbles in the liquid film layer. The method can remove bubbles in a liquid film layer, especially can remove micron-scale or nano-scale bubbles which cannot be removed by an existing method and can stably exist, and is especially suitable for removing bubbles in photoresist; therefore, the quality of the photoresist can be improved, photoetching exposure and developing processes are improved, and various cost wastes caused by reworking of the photoresist are saved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor integrated circuit manufacturing, and particularly to an apparatus for removing bubbles in a liquid film layer. The present invention also relates to a method for removing bubbles in a liquid film layer. Background Art

[0002] As an indispensable part of the lithography exposure process, photoresist plays a crucial role in transferring the pattern on the lithography mask to the surface of the wafer. As the design size of integrated circuits becomes smaller and smaller, the pattern that needs to be transferred from the mask to the wafer by the lithography process needs to be more and more precise. If there are bubbles in the photoresist, the refraction, scattering, diffraction, etc. of light by the bubbles, and the further multi-stage interference diffraction of the refracted light of multiple bubbles will cause the energy distribution on the photoresist not to accumulate exactly as expected, thereby interfering with the pattern transfer, and ultimately making it impossible to obtain a pattern with sufficiently high precision. Therefore, strictly removing bubbles of various magnitudes in the photoresist is crucial for ensuring the quality of the photoresist spin-coated on the wafer surface.

[0003] Currently, in the actual production process, the photoresist is pressurized by nitrogen to pass through a filter membrane and enter the buffer bottle in the lithography machine. Inevitably, a large number of bubbles will be generated in the photoresist during this process. After the bubbles are cut into micron-sized bubbles by the filter membrane, their stability is extremely strong and it is not easy to remove them by static means. The stability of nano-sized bubbles is extremely strong, especially in a high-molecular material such as photoresist, the mass transfer efficiency is greatly reduced, and their lifespan is extremely long without human intervention.

[0004] Most of the existing technical means use methods such as decompression and ultrasonic waves to only remove large bubbles and cannot effectively remove micro-nano bubbles. There is an urgent need for new means to remove them. The presence of bubbles will also cause defects in subsequent lithography processes such as development. The bubbles generated when the photoresist is supplied and distributed on the wafer surface cause secondary pollution, resulting in rework, wasting photoresist, wasting machine time, and wasting the cleaning cost of the photoresist ejection optical path. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an apparatus for removing bubbles in a liquid film layer, which can remove bubbles in the liquid film layer, especially can remove micron-sized or nano-sized bubbles that cannot be removed by existing methods and can stably exist, and is particularly suitable for removing bubbles in photoresist, so as to improve the quality of photoresist and the precision of lithography exposure, and can also improve the development quality of the lithography process and reduce the defects caused by bubbles, and can also prevent secondary pollution caused by bubbles and reduce the waste of photoresist caused by photoresist rework, reduce the waste of lithography machine time, and reduce the cleaning cost of the photoresist ejection pipeline. For this purpose, the present invention also provides a method for removing bubbles in a liquid film layer.

[0006] To solve the above technical problems, the device for removing bubbles in a liquid film layer provided by the present invention includes:

[0007] A base for placing a substrate coated with a liquid film layer.

[0008] A sealing cover arranged above the base and forming a sealed space above the base, and the substrate is located in the sealed space.

[0009] A cooling device and a vacuum pumping device are arranged in the sealing cover.

[0010] The cooling device is used to reduce the temperature of the sealed space to quickly freeze the liquid film layer.

[0011] The vacuum pumping device is used to pump the air in the sealed space after the liquid film layer is quickly frozen and to remove the bubbles in the liquid film layer by degassing.

[0012] Further improvement is that the bubbles in the liquid film layer coated on the substrate are in the micron order or the nanometer order.

[0013] Further improvement is that the cooling device includes a sandwich layer arranged in the sealing cover.

[0014] The sandwich layer includes a first inlet and a second outlet.

[0015] The first inlet is connected to a liquid cooling gas source through a first pipeline; when quickly freezing the liquid film layer, the liquid cooling gas is introduced into the sandwich layer.

[0016] The sandwich layer is located between the inner wall and the outer wall of the sealing cover, and the materials of the inner wall and the outer wall are opposite in temperature sensitivity; the inner wall is used to conduct heat between the liquid cooling gas and the sealed space, and the outer wall is used to achieve heat insulation between the liquid cooling gas and the outside of the sealing cover.

[0017] The second outlet is connected to a first vacuum pump through a second pipeline, and after the liquid film layer is quickly frozen, the first vacuum pump is used to pump the liquid cooling gas out of the sandwich layer.

[0018] Further improvement is that the liquid cooling gas includes liquid nitrogen.

[0019] Further improvement is that the first vacuum pump is a molecular pump.

[0020] A first valve is arranged on the first pipeline.

[0021] The first valve is opened before the liquid film layer is quickly frozen and closed after the liquid cooling gas fills the sandwich layer.

[0022] The first valve is an automatic control valve or a manual control valve.

[0023] A further improvement is that a second valve is provided on the second pipeline.

[0024] The connection and disconnection between the interior of the interlayer and the first vacuum pump are controlled by the second valve.

[0025] The second valve is an automatic control valve or a manual control valve.

[0026] A further improvement is that the vacuum pumping device includes a vacuum pumping port and a second vacuum pump.

[0027] The vacuum pumping port passes through the sealing cover and is connected to the second vacuum pump through a third pipeline.

[0028] A third valve is provided on the third pipeline.

[0029] The connection and disconnection between the sealed space and the second vacuum pump are controlled by the third valve.

[0030] The third valve is an automatic control valve or a manual control valve.

[0031] The second vacuum pump is a molecular pump.

[0032] A further improvement is that a sub-valve is also provided on the third valve, and the sub-valve is used to control the inflow of the vacuum-breaking gas into the sealed space.

[0033] A further improvement is that the vacuum-breaking gas includes nitrogen.

[0034] A further improvement is that it further includes:

[0035] A temperature sensor, which is arranged on the inner wall of the sealing cover and is used to measure the temperature of the sealed space in real time.

[0036] A pressure sensor, which is arranged on the inner wall of the sealing cover and is used to measure the pressure of the sealed space in real time.

[0037] An automatic control system, which is used to automatically control the cooling device and the vacuum pumping device.

[0038] A further improvement is that it further includes: a bubble detector, which is used to detect the concentration of bubbles in the liquid film layer.

[0039] A further improvement is that the liquid film layer includes a photoresist (PR) layer or an anti-reflection coating (ARC) layer.

[0040] The base is located in the structural unit of a lithographic exposure and development system.

[0041] A further improvement is that it further includes: a sealing ring; the sealing ring is arranged between the sealing cover and the base for sealing the sealing space.

[0042] To solve the above technical problems, the method for removing bubbles in a liquid film layer provided by the present invention includes the following steps:

[0043] Place the substrate coated with the liquid film layer on the base.

[0044] Set the sealing cover above the base and close it to form a sealing space above the base, and the substrate is located in the sealing space.

[0045] Use the cooling device of the sealing cover to lower the temperature of the sealing space to quickly freeze the liquid film layer.

[0046] After the liquid film layer is quickly frozen, use the vacuum pumping device of the sealing cover to pump the air in the sealing space to remove the bubbles in the liquid film layer.

[0047] A further improvement is that the bubbles in the liquid film layer coated on the substrate are in the micrometer or nanometer range.

[0048] A further improvement is that the liquid film layer includes a photoresist layer or an anti-reflection coating.

[0049] The liquid material of the liquid film layer is pumped out by a nitrogen pump in a buffer tank, filtered through a filter membrane, and then coated on the surface of the substrate by spin coating.

[0050] The base is located in the structural unit of a lithographic exposure and development system.

[0051] A further improvement is that the cooling device includes a sandwich layer arranged in the sealing cover.

[0052] The sandwich layer includes a first inlet and a second outlet.

[0053] The first inlet is connected to a liquid cooling gas source through a first pipeline; when quickly freezing the liquid film layer, the liquid cooling gas is introduced into the sandwich layer.

[0054] The sandwich layer is located between the inner wall and the outer wall of the sealing cover, and the materials of the inner wall and the outer wall are opposite in temperature sensitivity; the inner wall is used to conduct heat between the liquid cooling gas and the sealing space, and the outer wall is used to achieve heat insulation between the liquid cooling gas and the outside of the sealing cover.

[0055] The second outlet is connected to a first vacuum pump through a second pipeline. After the liquid film layer is quickly frozen, the first vacuum pump is used to pump the liquid cooling gas out of the interlayer.

[0056] A further improvement is that the liquid cooling gas includes liquid nitrogen.

[0057] A further improvement is that the first vacuum pump is a molecular pump.

[0058] A first valve is provided on the first pipeline.

[0059] The first valve is opened before the liquid film layer is quickly frozen and closed after the liquid cooling gas fills the interlayer.

[0060] The first valve is an automatic control valve or a manual control valve.

[0061] A further improvement is that a second valve is provided on the second pipeline.

[0062] The communication and cut-off between the inside of the interlayer and the first vacuum pump are controlled by the second valve.

[0063] The second valve is an automatic control valve or a manual control valve.

[0064] A further improvement is that the vacuum pumping device includes a vacuum pumping port and a second vacuum pump.

[0065] The vacuum pumping port passes through the sealing cover and is connected to the second vacuum pump through a third pipeline.

[0066] A third valve is provided on the third pipeline.

[0067] The communication and cut-off between the sealed space and the second vacuum pump are controlled by the third valve.

[0068] The third valve is an automatic control valve or a manual control valve.

[0069] The second vacuum pump is a molecular pump.

[0070] A further improvement is that a sub-valve is also provided on the third valve, and the sub-valve is used to control the inflow of the vacuum-breaking gas into the sealed space.

[0071] The degassing and the freeze-thaw of the liquid film layer are carried out simultaneously. After the liquid film layer is completely freeze-thawed, the sub-valve is opened to allow the vacuum-breaking gas to flow into the sealed space. After the freeze-thaw is completed and the sealed space returns to normal pressure, the sealing cover is opened.

[0072] After that, subsequent processes are carried out on the substrate.

[0073] A further improvement is that the vacuum-breaking gas includes nitrogen.

[0074] A further improvement is that a temperature sensor and a pressure sensor are also provided on the inner wall of the sealing cover.

[0075] The temperature sensor is used to measure the temperature of the sealed space in real time; the pressure sensor is used to measure the pressure of the sealed space in real time.

[0076] Control the operation of the cooling device and the vacuum pumping device according to the detected temperature and pressure of the sealed space.

[0077] A further improvement is that it further includes:

[0078] After the degassing and the freeze-thaw of the liquid film layer are completed, a bubble detector is used to detect the concentration of bubbles in the liquid film layer and alarm when the bubble concentration exceeds the threshold.

[0079] A further improvement is that it further includes: Before setting the sealing cover above the base, it further includes:

[0080] Pre-clean the sealing cover with a nitrogen gun.

[0081] Through the cooling device of the sealing cover, the present invention can achieve rapid freezing of the liquid film layer. After rapid freezing, the liquid film layer can be subjected to vacuum pumping. The present invention uses a vacuum pumping device to pump the sealed space to vacuum, so that the liquid film layer located in the sealed space can be degassed by vacuum pumping. The degassing process can remove the bubbles in the liquid film layer, especially the bubbles in the micron or nano scale that cannot be removed by the existing methods and will stably exist. Therefore, the present invention can remove the bubbles in the liquid film layer, especially the bubbles in the micron or nano scale that cannot be removed by the existing methods and can stably exist.

[0082] The present invention is particularly suitable for removing bubbles in photoresist. Since the lithography process has high requirements for the quality of photoresist, after removing the micron-scale and nano-scale bubbles in the photoresist, the following technical effects can be further obtained: it can improve the quality of photoresist and the accuracy of lithography exposure, can also improve the development quality of the lithography process and reduce the defects caused by bubbles, can prevent secondary pollution caused by bubbles, and can reduce the waste of photoresist caused by photoresist rework, reduce the waste of lithography machine time, and reduce the cleaning cost of the photoresist ejection pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] The present invention will be further described in detail below with reference to the drawings and specific embodiments:

[0084] Figure 1It is a schematic structural diagram of the device for removing bubbles in the liquid film layer in the embodiment of the present invention. Detailed implementation manners

[0085] As Figure 1 shown, it is a schematic structural diagram of the device for removing bubbles in the liquid film layer in the embodiment of the present invention; the device for removing bubbles in the liquid film layer in the embodiment of the present invention includes:

[0086] A base for placing the substrate 110 coated with the liquid film layer.

[0087] In the embodiment of the present invention, the bubbles in the liquid film layer coated on the substrate 110 are in the micron or nanometer order of magnitude.

[0088] The liquid film layer includes a photoresist layer or an anti-reflection coating.

[0089] The base is located in the structural unit of the lithography exposure and development system.

[0090] In Figure 1 the shown example, the base includes a chuck having a plurality of fingers 111, and the fingers 111 clamp and fix the substrate 110 on the base.

[0091] A sealing cover 101 is arranged above the base and forms a sealed space above the base, and the substrate 110 is located in the sealed space.

[0092] Figure 1 shows the sectional structure of the sealing cover 101, and two circularly surrounding arrow dotted lines indicate the three-dimensional structure of the sealing cover 101, and the three-dimensional structure can be a spherical shell shape. In other embodiments, the sealing cover 101 can also be other suitable three-dimensional structures.

[0093] The sealing cover 101 is provided with a cooling device and a vacuum pumping device.

[0094] The cooling device is used to reduce the temperature of the sealed space to quickly freeze the liquid film layer.

[0095] In the embodiment of the present invention, the cooling device includes an interlayer 102 arranged in the sealing cover 101.

[0096] The interlayer 102 includes a first inlet and a second outlet.

[0097] The first inlet is connected to a liquid cooling gas source 104 through a first pipeline 103; when quickly freezing the liquid film layer, the liquid cooling gas is introduced into the interlayer 102.

[0098] The liquid cooling gas includes liquid nitrogen. In other embodiments, other suitable liquid gases can also be used as the liquid cooling gas, such as liquid helium, liquid argon, etc.

[0099] The interlayer 102 is located between the inner wall 101b and the outer wall 101a of the sealing cover 101, and the materials of the inner wall 101b and the outer wall 101a have opposite temperature sensitivities; the inner wall 101b is used to conduct heat between the liquid cooling gas and the sealed space, and the outer wall 101a is used to insulate heat between the liquid cooling gas and the outside of the sealing cover 101. In some embodiments, the inner wall 101b can be made of metal to achieve good heat conduction; the outer wall 101a is made of an insulating dielectric material or a composite layer of an insulating dielectric material and metal to achieve good heat insulation.

[0100] The second outlet is connected to the first vacuum pump 106a through the second pipeline 105. After the liquid film layer is quickly frozen, the first vacuum pump 106a is used to pump out the liquid cooling gas from the interlayer 102.

[0101] In some embodiments, the first vacuum pump 106a is a molecular pump.

[0102] A first valve is provided on the first pipeline 103.

[0103] The first valve is opened before the liquid film layer is quickly frozen and closed after the liquid cooling gas fills the interlayer 102.

[0104] In the embodiments of the present invention, the first valve is an automatic control valve. In some embodiments, the automatic control valve can be a solenoid valve or a pneumatic valve, which can achieve remote control.

[0105] In other embodiments, it can also be: the first valve is a manually controlled valve.

[0106] A second valve is provided on the second pipeline 105.

[0107] The communication and cut-off between the inside of the interlayer 102 and the first vacuum pump 106a are controlled by the second valve.

[0108] In the embodiments of the present invention, the second valve is an automatic control valve. In other embodiments, it can also be: the second valve is a manually controlled valve.

[0109] The vacuum pumping device is used to pump the sealed space to vacuum after the liquid film layer is quickly frozen and to remove the bubbles in the liquid film layer by degassing.

[0110] In the embodiment of the present invention, the vacuum pumping device includes: a vacuum pumping port 107 and a second vacuum pump 106b.

[0111] The vacuum pumping port 107 passes through the sealing cover 101 and is connected to the second vacuum pump 106b through a third pipeline.

[0112] A third valve is provided on the third pipeline.

[0113] The connection and disconnection between the sealed space and the second vacuum pump 106b are controlled by the third valve.

[0114] In the embodiment of the present invention, the third valve is an automatic control valve. In other embodiments, it can also be: the third valve is a manual control valve.

[0115] In some embodiments, the second vacuum pump 106b is a molecular pump.

[0116] In the embodiment of the present invention, a sub-valve is further provided on the third valve, and the sub-valve is used to control the inflow of the vacuum-breaking gas into the sealed space.

[0117] In some embodiments, the vacuum-breaking gas includes nitrogen. In other embodiments, other suitable gases can also be used for the vacuum-breaking gas, such as: inert gases, such as argon, etc.

[0118] The embodiment of the present invention further includes:

[0119] A temperature sensor 108, which is arranged on the inner wall 101b of the sealing cover 101 and is used to measure the temperature of the sealed space in real time.

[0120] A pressure sensor 109, which is arranged on the inner wall 101b of the sealing cover 101 and is used to measure the pressure of the sealed space in real time.

[0121] An automatic control system, which is used for automatic control of the cooling device and the vacuum pumping device. For example, it can perform automatic control on each valve, namely the first to third valves; it can also perform automatic control in combination with the detected temperature and pressure. In some embodiments, the automatic control system can be implemented by the machine platform of a lithography machine, and the control of the process flow and the components required in the process flow is achieved through the setting of a process menu (recipe).

[0122] The embodiment of the present invention further includes: a bubble detector, which is used to detect the concentration of bubbles in the liquid film layer. The bubble detector will alarm when the detected bubble concentration exceeds the threshold. In this way, the step of removing bubbles in the liquid film layer needs to be continued.

[0123] In an embodiment of the present invention, it further includes: a sealing ring; the sealing ring is disposed between the sealing cover 101 and the base, and is used to seal the sealed space. The sealing ring needs to have elasticity so that the contact position between the sealing cover 101 and the base can be closely attached. At the same time, the material of the sealing ring can withstand the temperature change of the sealed space.

[0124] In the embodiment of the present invention, the cooling device of the sealing cover 101 can achieve rapid freezing of the liquid film layer. After rapid freezing, the liquid film layer can be subjected to a vacuum pumping process. The embodiment of the present invention uses a vacuum pumping device to pump the sealed space to a vacuum, so that the liquid film layer located in the sealed space can be degassed by vacuum pumping. The degassing process can remove the bubbles in the liquid film layer, especially the micron-sized or nano-sized bubbles that cannot be removed by existing methods and will stably exist. Therefore, the embodiment of the present invention can remove the bubbles in the liquid film layer, especially the micron-sized or nano-sized bubbles that cannot be removed by existing methods and can stably exist.

[0125] The embodiment of the present invention is particularly suitable for removing bubbles in photoresist. Since the lithography process has high quality requirements for photoresist, after removing the micron-sized and nano-sized bubbles in the photoresist, the following technical effects can be further achieved: improving the quality of photoresist and the accuracy of lithography exposure, improving the development quality of the lithography process and reducing the defects caused by bubbles, preventing secondary pollution caused by bubbles, reducing the waste of photoresist caused by photoresist rework, reducing the machine time waste of the lithography machine, and reducing the cleaning cost of the photoresist ejection pipeline.

[0126] The embodiment of the present invention can effectively remove the micro-nano bubbles stably existing in the photoresist or chemical solutions such as ARC uniformly coated on the surface of the wafer before exposure.

[0127] In the embodiment of the present invention, the mass of the lid, i.e., the sealing cover 101, is extremely small, and the texture is extremely hard, and it can withstand drastic pressure changes, and the range includes negative pressure close to vacuum; the lid has a sandwich layer, in which liquid nitrogen and the like are introduced. After introducing liquid nitrogen into the sandwich layer, the inner side is rapidly cooled, so that the sealed space between the lid and the chuck is rapidly cooled, and the photoresist or chemical solutions such as ARC coated on the surface of the wafer are instantly frozen.

[0128] In the embodiment of the present invention, the sandwich layer has two openings. The inlet, i.e., the first inlet, has a standardized design and can be connected to a conventional device for introducing liquid nitrogen, which is convenient for introducing liquid nitrogen. The inlet is equipped with a remotely controllable fully automatic switch valve, i.e., the first valve, and the valve automatically closes after the sandwich layer of the lid is filled with liquid nitrogen; the outlet, i.e., the second outlet, has a standardized design and can be connected to a molecular pump, and is used to pump out the liquid nitrogen in the photoresist or chemical solutions such as ARC uniformly coated on the surface of the wafer after being rapidly frozen.

[0129] In an embodiment of the present invention, there is a vacuum pumping interface, i.e., a vacuum pumping port 107, at the top of the lid. The interface is designed in a standardized manner and can be connected to a molecular pump, which is used to pump out gases from the above-mentioned sealed space during the freeze-thaw process of chemical solutions such as photoresist or ARC, so as to achieve the effect of removing micro-nano bubbles therein.

[0130] In an embodiment of the present invention, a temperature and pressure sensor integrated in the lid can reflect the pressure and temperature in the formed sealed space, thereby automatically regulating each switch and detecting the internal situation.

[0131] In an embodiment of the present invention, an integrated bubble detector detects micro-nano scale bubbles in a liquid film layer such as photoresist or ARC uniformly coated on the surface of a wafer, i.e., a substrate 110, after the freeze-thaw degassing is completed. The bubble detector uses the signal generated by the refraction of laser light passing through the above-mentioned chemical solution by the micro-nano bubbles therein to calculate the concentration of the bubbles therein, and issues an alarm when the bubble content exceeds the threshold.

[0132] The method for removing bubbles in the liquid film layer in an embodiment of the present invention includes the following steps:

[0133] Step 1: Place the substrate 110 coated with the liquid film layer on the base.

[0134] In the method of the embodiment of the present invention, the bubbles in the liquid film layer coated on the substrate 110 are in the micron scale or nanoscale.

[0135] The liquid film layer includes a photoresist layer or an anti-reflection coating.

[0136] The base is located in a structural unit of a lithography exposure and development system.

[0137] In Figure 1 In the shown example, the base includes a chuck having a plurality of fingers 111, and the fingers 111 clamp and fix the substrate 110 on the base.

[0138] Step 2: Set the sealing cover 101 above the base and close it to form a sealed space above the base, and the substrate 110 is located in the sealed space.

[0139] Figure 1 shows the cross-sectional structure of the sealing cover 101, and two circularly surrounding arrow dotted lines indicate the three-dimensional structure of the sealing cover 101, and the three-dimensional structure can be a spherical shell. In other embodiment methods, the sealing cover 101 can also be other suitable three-dimensional structures.

[0140] Step 3: Use the cooling device of the sealing cover 101 to reduce the temperature of the sealed space so as to quickly freeze the liquid film layer.

[0141] In the method of the embodiment of the present invention, the cooling device includes a sandwich layer 102 provided in the sealing cover 101.

[0142] The sandwich layer 102 includes a first inlet and a second outlet.

[0143] The first inlet is connected to a liquid cooling gas source 104 through a first pipeline 103; when quickly freezing the liquid film layer, the liquid cooling gas is introduced into the sandwich layer 102.

[0144] The liquid cooling gas includes liquid nitrogen. In the methods of other embodiments, other suitable liquid gases can also be used for the liquid cooling gas, such as: liquid helium, liquid argon, etc.

[0145] The sandwich layer 102 is located between the inner wall 101b and the outer wall 101a of the sealing cover 101, and the materials of the inner wall 101b and the outer wall 101a are opposite in temperature sensitivity; the inner wall 101b is used to achieve heat conduction between the liquid cooling gas and the sealed space, and the outer wall 101a is used to achieve heat insulation between the liquid cooling gas and the outside of the sealing cover 101. In the methods of some embodiments, the inner wall 101b can be made of metal, so as to achieve good heat conduction; the outer wall 101a is made of an insulating dielectric material or a composite layer of an insulating dielectric material and metal, so as to achieve good heat insulation.

[0146] The second outlet is connected to a first vacuum pump 106a through a second pipeline 105. After the liquid film layer is quickly frozen, the first vacuum pump 106a is used to pump out the liquid cooling gas from the sandwich layer 102.

[0147] In the methods of some embodiments, the first vacuum pump 106a is a molecular pump.

[0148] A first valve is provided on the first pipeline 103.

[0149] The first valve is opened before the liquid film layer is quickly frozen and closed after the sandwich layer 102 is filled with the liquid cooling gas.

[0150] In the method of the embodiment of the present invention, the first valve is an automatically controlled valve. In the methods of some embodiments, the automatically controlled valve can be a solenoid valve or a pneumatic valve, and remote control can be achieved.

[0151] In the methods of other embodiments, it can also be: the first valve is a manually controlled valve.

[0152] A second valve is provided on the second pipeline 105.

[0153] The communication and cut-off between the inside of the interlayer 102 and the first vacuum pump 106a are controlled by the second valve.

[0154] In the method of the embodiment of the present invention, the second valve is an automatic control valve. In the methods of other embodiments, it can also be that the second valve is a manual control valve.

[0155] Step Four: After the liquid film layer is quickly frozen, the vacuum pumping device of the sealing cover 101 is used to pump the air in the sealed space to remove the bubbles in the liquid film layer.

[0156] In the method of the embodiment of the present invention, the vacuum pumping device includes a vacuum pumping port 107 and a second vacuum pump 106b.

[0157] The vacuum pumping port 107 passes through the sealing cover 101 and is connected to the second vacuum pump 106b through a third pipeline.

[0158] A third valve is provided on the third pipeline.

[0159] The communication and cut-off between the sealed space and the second vacuum pump 106b are controlled by the third valve.

[0160] In the method of the embodiment of the present invention, the third valve is an automatic control valve. In the methods of other embodiments, it can also be that the third valve is a manual control valve.

[0161] In some embodiments of the method, the second vacuum pump 106b is a molecular pump.

[0162] In the method of the embodiment of the present invention, the degassing and the freeze-thaw of the liquid film layer are carried out simultaneously. After the liquid film layer is completely freeze-thawed, it further includes:

[0163] Step Five: Open the sub-valve of the third valve to allow the vacuum-breaking gas to flow into the sealed space. After the freeze-thaw is completed and the sealed space returns to normal pressure, open the sealing cover 101.

[0164] The sub-valve is used to control the flow of the vacuum-breaking gas into the sealed space.

[0165] In some embodiments of the method, the vacuum-breaking gas includes nitrogen. In the methods of other embodiments, other suitable gases can also be used as the vacuum-breaking gas, such as inert gases, such as argon.

[0166] In the method of the embodiment of the present invention, a temperature sensor 108 and a pressure sensor 109 are further provided on the inner wall 101b of the sealing cover 101.

[0167] The temperature sensor 108 is used to measure the temperature of the sealed space in real time; the pressure sensor 109 is used to measure the pressure of the sealed space in real time.

[0168] Control the operation of the cooling device and the vacuum pumping device according to the detected temperature and pressure of the sealed space, including: automatically controlling the switching of the first valve, the second valve, and the third valve according to the detected temperature or pressure of the sealed space.

[0169] In the method of the embodiment of the present invention, each step is controlled by an automated control system. The automated control system can automatically control the cooling device and the vacuum pumping device. For example, it can automatically control each valve, namely the first to the third valves; it can also perform automatic control in combination with the detected temperature and pressure. In some embodiment methods, the automated control system can be implemented by the machine platform of a lithography machine, and the control of the process flow and the components required in the process flow is achieved through the setting of a process recipe.

[0170] It further includes:

[0171] Step six: After the degassing and the freeze-thaw of the liquid film layer are completed, use a bubble detector to detect the concentration of bubbles in the liquid film layer and alarm when the bubble concentration exceeds the threshold.

[0172] In the method of the embodiment of the present invention, before setting the sealing cover 101 above the base, it further includes:

[0173] Pre-clean the sealing cover 101 with a nitrogen gun.

[0174] In the method of the embodiment of the present invention:

[0175] When the liquid film layer is a photoresist, in step one, it further includes that the photoresist is pumped out by a nitrogen pump through a buffer tank and spin-coated on the surface of the silicon wafer, that is, the substrate, through a filter membrane. Then, in step two, the robotic arm drives the lid, that is, the sealing cover 101, above the wafer table, accurately anchors the position of the wafer table through a detector built in the lid, and closes it accurately.

[0176] Open the valve for introducing liquid nitrogen into the interlayer through the automated control system integrated on the lid, fill the interlayer with liquid nitrogen, and automatically close the inlet valve.

[0177] The photoresist or chemical solution such as ARC on the wafer surface is quickly frozen by liquid nitrogen, and the outlet valve of the lid interlayer is automatically opened and pumped out automatically by a molecular pump connected thereto.

[0178] The quick-freezing is completed. Subsequently, the degassing outlet valve connecting the closed space above the lid and the chuck automatically opens, and the molecular pump connected to it starts operating. The freeze-thaw and degassing processes are carried out simultaneously. When the air pressure in the closed space approaches vacuum, the valve at the pumping outlet, i.e., the third valve, automatically closes. When the chemical solution such as photoresist or ARC in it is completely freeze-thawed, the sub-valve of the degassing outlet valve, i.e., the third valve, is automatically opened, and the gas flow rate of the sub-valve is controlled to be less than 10 milliliters per minute. After the freeze-thaw is completed, the lid is automatically opened, and the robotic arm drives the lid to move away. Subsequent operations such as exposure and development are carried out.

[0179] The method of the embodiment of the present invention can effectively improve the efficiency of removing defects generated in subsequent photolithography processes such as development due to the presence of bubbles; can reduce the secondary contamination of bubbles generated when the photoresist is supplied and distributed onto the wafer surface; can effectively reduce the probability of reworking to remove the photoresist on the entire wafer; can effectively save the nearly one-hour operation time spent on clearing the pipeline due to the ejection of the bubble-containing photoresist from the pipeline; can reduce the waste of photoresist and avoid the waste of machine time.

[0180] The present invention has been described in detail through specific embodiments above, but these do not constitute a limitation to the present invention. Without departing from the principle of the present invention, those skilled in the art can also make many deformations and improvements, which should also be regarded as the protection scope of the present invention.

Claims

1. An apparatus for removing bubbles in a liquid film layer, characterized in that, Comprising: A base for placing a substrate coated with a liquid film layer; A sealing cover disposed above the base and forming a sealed space above the base, with the substrate located in the sealed space; A cooling device and a vacuum pumping device are provided in the sealing cover; The cooling device is used to reduce the temperature of the sealed space to rapidly freeze the liquid film layer; The vacuum pumping device is used to pump vacuum in the sealed space after the liquid film layer is rapidly frozen and to remove the bubbles in the liquid film layer by degassing.

2. The device for removing bubbles in the liquid film layer according to claim 1, wherein: The bubbles in the liquid film layer coated on the substrate are in the micron or nanometer range.

3. The device for removing bubbles in the liquid film layer according to claim 1, characterized in that: The cooling device includes a sandwich layer provided in the sealing cover; The sandwich layer includes a first inlet and a second outlet; The first inlet is connected to a liquid cooling gas source through a first pipeline; when rapidly freezing the liquid film layer, the liquid cooling gas is introduced into the sandwich layer; The sandwich layer is located between the inner wall and the outer wall of the sealing cover, and the materials of the inner wall and the outer wall have opposite temperature sensitivities; the inner wall is used to conduct heat between the liquid cooling gas and the sealed space, and the outer wall is used to achieve heat insulation between the liquid cooling gas and the outside of the sealing cover; The second outlet is connected to a first vacuum pump through a second pipeline, and after the liquid film layer is rapidly frozen, the first vacuum pump is used to pump out the liquid cooling gas from the sandwich layer.

4. The device for removing bubbles in the liquid film layer according to claim 3, characterized in that: The liquid cooling gas includes liquid nitrogen.

5. The device for removing air bubbles in the liquid film layer according to claim 3, wherein: The first vacuum pump is a molecular pump; A first valve is provided on the first pipeline; The first valve is opened before the liquid film layer is rapidly frozen and closed after the sandwich layer is filled with the liquid cooling gas; The first valve is an automatic control valve or a manual control valve.

6. The device for removing bubbles in the liquid film layer according to claim 3, wherein: A second valve is provided on the second pipeline; The connection and disconnection between the inside of the sandwich layer and the first vacuum pump are controlled through the second valve; The second valve is an automatic control valve or a manual control valve.

7. The device for removing bubbles in the liquid film layer according to claim 1, wherein: The vacuum pumping device includes: a vacuum pumping port and a second vacuum pump; The vacuum pumping port penetrates through the sealing cover and is connected to the second vacuum pump through a third pipeline; A third valve is provided on the third pipeline; The connection and disconnection between the sealed space and the second vacuum pump are controlled through the third valve; The third valve is an automatic control valve or a manual control valve; The second vacuum pump is a molecular pump.

8. The device for removing bubbles in the liquid film layer according to claim 7, wherein: A sub-valve is further provided on the third valve, and the sub-valve is used to control the inflow of breaking vacuum gas into the sealed space.

9. The device for removing air bubbles in the liquid film layer according to claim 8, wherein: The breaking vacuum gas includes nitrogen.

10. The device for removing bubbles in the liquid film layer according to claim 3, characterized in that, Further comprising: A temperature sensor, which is provided on the inner wall of the sealing cover and is used to measure the temperature of the sealed space in real time; A pressure sensor, which is provided on the inner wall of the sealing cover and is used to measure the pressure of the sealed space in real time; An automatic control system for automatically controlling the cooling device and the vacuum pumping device.

11. The device for removing bubbles in the liquid film layer according to claim 1, wherein, Further comprising: A bubble detector for detecting the concentration of bubbles in the liquid film layer.

12. The device for removing air bubbles in the liquid film layer according to claim 1, wherein: The liquid film layer includes a photoresist layer or an anti-reflection coating; The base is located in a structural unit of a photolithography exposure and development system.

13. The device for removing bubbles in the liquid film layer according to claim 1, characterized in that, Further comprising: Sealing ring; the sealing ring is arranged between the sealing cover and the base, and is used to seal the sealed space.

14. A method for removing bubbles in a liquid film layer, characterized in that, It includes the following steps: Place the substrate coated with the liquid film layer on the base; Set the sealing cover above the base and close it to form a sealed space above the base, and the substrate is located in the sealed space; Use the cooling device of the sealing cover to lower the temperature of the sealed space to quickly freeze the liquid film layer; After the liquid film layer is quickly frozen, use the vacuum pumping device of the sealing cover to pump the air in the sealed space to remove the bubbles in the liquid film layer.

15. The method for removing bubbles in the liquid film layer according to claim 14, characterized in that: The bubbles in the liquid film layer coated on the substrate are in the micron or nanometer range.

16. The method for removing air bubbles in a liquid film layer according to claim 15, characterized in that: The liquid film layer includes a photoresist layer or an anti-reflection coating; The liquid material of the liquid film layer is pumped out by a nitrogen pump in a buffer tank, filtered through a filter membrane, and then coated on the surface of the substrate by spin coating; The base is located in the structural unit of a lithography exposure and development system.

17. The method for removing air bubbles in the liquid film layer according to claim 14, characterized in that: The cooling device includes a sandwich layer arranged in the sealing cover; The sandwich layer includes a first inlet and a second outlet; The first inlet is connected to a liquid cooling gas source through a first pipeline; when quickly freezing the liquid film layer, the liquid cooling gas is introduced into the sandwich layer; The sandwich layer is located between the inner wall and the outer wall of the sealing cover, and the materials of the inner wall and the outer wall are opposite in temperature sensitivity; the inner wall is used to conduct heat between the liquid cooling gas and the sealed space, and the outer wall is used to insulate between the liquid cooling gas and the outside of the sealing cover; The second outlet is connected to a first vacuum pump through a second pipeline. After the liquid film layer is quickly frozen, the first vacuum pump is used to pump the liquid cooling gas out of the sandwich layer.

18. The method for removing bubbles in the liquid film layer according to claim 17, wherein: The liquid cooling gas includes liquid nitrogen.

19. The method for removing air bubbles in the liquid film layer according to claim 17, wherein: The first vacuum pump is a molecular pump; A first valve is arranged on the first pipeline; The first valve is opened before the liquid film layer is quickly frozen and closed after the liquid cooling gas fills the sandwich layer; The first valve is an automatic control valve or a manual control valve.

20. The method for removing air bubbles in the liquid film layer according to claim 17, wherein: A second valve is arranged on the second pipeline; The connection and disconnection between the inside of the sandwich layer and the first vacuum pump are controlled by the second valve; The second valve is an automatic control valve or a manual control valve.

21. The method for removing bubbles in the liquid film layer according to claim 14, characterized in that: The vacuum pumping device includes: a vacuum pumping port and a second vacuum pump; The vacuum pumping port passes through the sealing cover and is connected to the second vacuum pump through a third pipeline; A third valve is arranged on the third pipeline; The connection and disconnection between the sealed space and the second vacuum pump are controlled by the third valve; The third valve is an automatic control valve or a manual control valve; The second vacuum pump is a molecular pump.

22. The method for removing bubbles in the liquid film layer according to claim 21, wherein: A sub-valve is also arranged on the third valve, and the sub-valve is used to control the inflow of the vacuum-breaking gas into the sealed space; The degassing and the freeze-thaw of the liquid film layer are carried out simultaneously. After the liquid film layer is completely frozen and thawed, the sub-valve is opened to allow the vacuum-breaking gas to flow into the sealed space. After the freeze-thaw ends and the sealed space returns to normal pressure, the sealing cover is opened; After that, subsequent processes are carried out on the substrate.

23. The method for removing air bubbles in the liquid film layer according to claim 17, characterized in that: A temperature sensor and a pressure sensor are also provided on the inner wall of the sealing cover; The temperature sensor is used to measure the temperature of the sealed space in real time; the pressure sensor is used to measure the pressure of the sealed space in real time; The operation of the cooling device and the vacuum pumping device is controlled according to the detected temperature and pressure of the sealed space.

24. The method for removing air bubbles in a liquid film layer according to claim 14, wherein It further includes: After the degassing and the freeze-thaw of the liquid film layer are completed, a bubble detector is used to detect the concentration of bubbles in the liquid film layer and alarm when the bubble concentration exceeds the threshold.

25. The method for removing air bubbles in the liquid film layer according to claim 14, characterized in that, It further includes: Before the sealing cover is disposed above the base, it further includes: Pre-cleaning the sealing cover with a nitrogen gun.

Images