Immersion boundary flow field convergence and removal method for IC lithography equipment based on organic medium

Abstract

The present invention discloses a method for converging and removing the immersion boundary flow field of an IC lithography device based on an organic medium. A super oleophobic coating is uniformly sprayed on the part where the immersion liquid on the substrate of the IC lithography device is not sufficiently recovered, and then a heat treatment is performed; the immersion boundary flow field is filled with the immersion liquid through an immersion supply system to complete the converging; at the same time, the immersion liquid flows out for recovery; the immersion liquid is recovered through the immersion supply system until it completely flows out, and the removal is completed. The present invention sprays a super oleophobic coating on the part where the immersion liquid is not sufficiently recovered, which can increase the contact angle of the fluid on the surface of the substrate without affecting the exposure conditions and the fluid properties, improve the flow characteristics of the fluid on the substrate, eliminate fluid residues, and achieve the effects of uniform and complete filling and complete recovery of the organic medium; the present invention does not need to change the structure of the substrate itself, improves the use efficiency of the organic medium, reduces costs while improving production efficiency, and ultimately improves the exposure quality.

Description

Technical Field

[0001] The invention relates to a boundary flow field convergence and removal method, in particular to an organic medium-based IC lithography equipment immersion boundary flow field convergence and removal method. Background Art

[0002] The traditional dry lithography medium is air, and it can only be upgraded by increasing the wavelength λ, so the resolution is relatively limited. The refractive index of liquid medium is higher than that of air, so the use of liquid medium can increase the numerical aperture of the objective lens and bring higher lithography resolution. The existing integrated circuit IC (Integrated Circuit) lithography equipment immersion system mainly uses ultrapure water as the filling medium. Ultrapure water has a low refractive index and a large characteristic line width. Compared with ultrapure water, organic media has a higher refractive index n, which allows the lithography system to obtain a finer lithography resolution R.

[0003] The properties of the organic medium itself also lead to certain problems in the process of use. The organic medium itself has a high viscosity, and the selected sapphire substrate (Al 2 O 3 ) is an oleophilic material, which results in the organic medium not flowing ideally on the substrate. When the organic medium is recycled, problems such as slow recycling speed, incomplete recycling, and a lot of residual liquid on the substrate will occur.

[0004] At present, the immersion unit of the lithography equipment designed by most lithography machine manufacturers cannot achieve complete filling or recycling, and may cause insufficient filling, leakage of organic media or insufficient recycling. Insufficient filling may affect the etching effect of the lithography machine, insufficient recycling will cause waste of organic immersion liquid, and leakage of organic media may cause pollution and affect the etching effect. At present, most practices are to improve the recycling efficiency by changing the structure of the immersion flow field. However, this method has great limitations and is also costly. At present, due to the surface fluid characteristics of the substrate material during the filling and recycling of fluid in the immersion boundary flow field of IC lithography equipment, a certain amount of fluid residue is left at the boundary, which reduces the exposure quality. Summary of the invention

[0005] In order to solve the problems existing in the background technology, the present invention provides an organic medium-based IC lithography equipment immersion boundary flow field convergence and removal method. The method of the present invention can completely fill and recycle the organic medium in the immersion unit, reduce costs, improve production efficiency, and improve exposure quality without changing exposure conditions.

[0006] The technical solution adopted by the present invention is:

[0007] The organic medium-based IC lithography equipment immersion boundary flow field convergence and removal method of the present invention comprises:

[0008] S1: The super oleophobic coating is uniformly sprayed on the substrate of the IC lithography equipment at the place where the immersion liquid is not fully recovered, and after the spraying is completed, a layer of transparent super oleophobic film is formed and heated.

[0009] S2: injecting immersion liquid into the immersion liquid inlet of the IC lithography equipment at a certain injection speed through the immersion supply system to fill the immersion boundary flow field in the IC lithography equipment and complete the convergence of the immersion boundary flow field; and at the same time, the immersion liquid flows out from the immersion liquid outlet of the IC lithography equipment at a certain recovery speed for recovery.

[0010] S3: the immersion supply system is controlled to stop injecting immersion liquid, and the immersion liquid flows out from the immersion liquid outlet of the IC lithography equipment. The immersion liquid is recovered through the immersion supply system until the immersion liquid flows out completely. No immersion liquid exists at the place where the immersion liquid is not fully recovered, and the removal of the immersion boundary flow field is completed.

[0011] In the step S1, immersion liquid is injected into the immersion liquid inlet of the IC lithography equipment, and the immersion liquid flows out from the immersion liquid outlet of the IC lithography equipment. After the injection of the immersion liquid stops, the immersion liquid flows out until it no longer flows out, and the position where the immersion liquid exists on the substrate of the IC lithography equipment is regarded as the place where the immersion liquid is insufficiently recovered.

[0012] In the step S1, the super oleophobic coating adopts a fluorine-silicon modified silica solution, which will not affect the exposure conditions of the exposure area of ​​the IC lithography equipment and the properties of the immersion liquid itself; there is no need to change the structure of the substrate itself, and the recovery rate of the immersion liquid can be improved by spraying the super oleophobic coating to achieve complete recovery; the gas tank pressure needs to be controlled during spraying, and the coating is evenly sprayed on the surface of the substrate to ensure that the immersion liquid can flow.

[0013] In the step S1, the contact angle between the position of the substrate where the transparent superoleophobic film is located and the injected immersion liquid is greater than 140°.

[0014] In the step S1, the heating treatment is specifically to bake the substrate of the IC lithography equipment in an oven at 90-110° C. for 10 minutes to improve its adhesion.

[0015] In the step S2, the immersion supply system includes two micro-injection pumps, which are respectively installed at the immersion liquid inlet and the immersion liquid outlet of the IC lithography equipment.

[0016] In the step S2, the injection speed and the recovery speed are both 5-6 ml / min.

[0017] The beneficial effects of the present invention are:

[0018] The present invention, before the immersion supply system is turned on, reclaims the insufficient part of the immersion liquid, sprays a certain thickness of super oleophobic coating, improves the flow characteristics of the fluid on the substrate, eliminates fluid residues, and achieves the purpose of complete recovery. The super oleophobic coating used in the present invention is a fluorine-silicon modified silica solution, which is completely transparent, increases the contact angle of the fluid on the substrate surface without affecting the exposure conditions and fluid characteristics, improves the fluid flow state, and can achieve the effects of uniform and complete filling of organic media and complete recovery, and finally improves the exposure quality. The present invention does not need to change the substrate structure itself, improves the use efficiency of organic media, reduces costs, and improves production efficiency, and improves exposure quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of IC lithography equipment;

[0020] Figure 2 is a cross-sectional view of the immersed boundary flow field;

[0021] Figure 3 It is a cross-sectional view of the substrate of an IC lithography device;

[0022] Figure 4 It is a schematic diagram of the fluid residue on the substrate of IC lithography equipment before and after spraying the coating, where: Figure 4 (a) is a schematic diagram of the residual fluid on the substrate of the IC lithography equipment after the coating is not sprayed. Figure 4 (b) is a schematic diagram of the fluid residue on the substrate of the IC lithography equipment after spray coating.

[0023] In the figure: 1, exposure area, 2, immersion liquid inlet, 3, immersion liquid outlet, 4, immersion liquid, 5, substrate. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The method for converging and removing the immersion boundary flow field of IC lithography equipment based on organic medium of the present invention is as follows:

[0026] S1: injecting immersion liquid 4 into the immersion liquid inlet 2 of the IC lithography equipment, and letting the immersion liquid 4 flow out from the immersion liquid outlet 3 of the IC lithography equipment; after the injection of the immersion liquid 4 stops, letting the immersion liquid 4 flow out until it stops flowing out, and treating the position where the immersion liquid 4 exists on the substrate 5 of the IC lithography equipment as the insufficient immersion liquid recovery position; spraying the super oleophobic coating evenly on the insufficient immersion liquid recovery position on the substrate 5 of the IC lithography equipment, forming a layer of transparent super oleophobic film after the spraying is completed, and performing a heat treatment, that is, baking the substrate 5 of the IC lithography equipment in an oven at 90-110°C for 10 minutes to improve its adhesion.

[0027] The superoleophobic coating uses a fluorine-silicon modified silica solution, which will not affect the exposure conditions of the exposure area 1 of the IC lithography equipment and the properties of the immersion liquid 4 itself; there is no need to change the structure of the substrate itself, and spraying the superoleophobic coating can increase the recovery rate of the immersion liquid 4 to achieve complete recovery; the gas tank pressure must be controlled during spraying, and the coating must be evenly sprayed on the surface of the substrate 5 to ensure that the immersion liquid 4 can flow.

[0028] S2: The immersion liquid 4 is injected into the immersion liquid inlet 2 of the IC lithography equipment at a certain injection speed through the immersion supply system to fill the immersion boundary flow field in the IC lithography equipment and complete the convergence of the immersion boundary flow field; and at the same time, the immersion liquid 4 is discharged from the immersion liquid outlet 3 of the IC lithography equipment at a certain recovery speed for recovery. The contact angle between the position of the substrate 5 where the transparent superoleophobic film is located and the injected immersion liquid 4 is greater than 140°.

[0029] In the past, spray coatings were generally used to protect materials, but in the present invention, spray coatings are used to improve the flow of liquids. The contact angle is related to oleophobicity. Good oleophobicity means less liquid residue. However, currently, oleophobicity is improved by changing the surface microstructure of the substrate material itself. In the present invention, oleophobicity is directly improved by spray coating.

[0030] S3: The immersion supply system is controlled to stop injecting the immersion liquid 4, and the immersion liquid 4 flows out from the immersion liquid outlet 3 of the IC lithography equipment. The immersion liquid 4 is recovered through the immersion supply system until the immersion liquid 4 flows out completely. There is no immersion liquid 4 at the place where the immersion liquid is not fully recovered, and the removal of the immersion boundary flow field is completed. The immersion supply system includes two micro-injection pumps, which are respectively installed at the immersion liquid inlet 2 and the immersion liquid outlet 3 of the IC lithography equipment. The injection speed and recovery speed of the micro-injection pump are both 5-6ml / min.

[0031] The following is a description of the specific implementation mode in conjunction with the accompanying drawings:

[0032] like Figure 1 As shown, the IC lithography equipment immersion lithography machine adopts an immersion liquid filling and recovery structure. The substrate 5 of the immersion liquid filling and recovery structure is removed, and it is cleaned and dried to prevent liquid residue from affecting the filling rate and recovery rate. Secondly, the fluorine-silicon modified silica solution is loaded into the aerosol tank, and the flow rate and air pressure are adjusted to spray it evenly on the insufficiently recovered areas on the surface of the bottom 5, such as Figure 3 The dotted lines at the four corners of the substrate 5 are where the superoleophobic coating is sprayed. After standing and drying, the substrate 5 is placed in an oven and baked at 100° C. for 10 minutes to ensure the adhesion of the coating on the substrate 5 .

[0033] Use a microinjection pump to set a certain flow rate for the immersion liquid inlet 2. The flow rates of the immersion liquid inlet 2 and the immersion liquid outlet 3 are both 5 ml / min or 6 ml / min to prevent bubbles or uneven fluid filling during the filling process caused by inconsistent inlet and outlet flow rates.

[0034] Open the immersion liquid supply system and allow the fluid to fill evenly and slowly. Figure 2 In the exposure area 1, the immersed boundary flow field is completely filled, and the fluid is kept flowing but is always completely filled in the immersed boundary flow field.

[0035] Turn off the immersion liquid supply system, change the flow rate of the microinjection pump so that the flow rate of the immersion liquid inlet 2 is 0 ml / min to prevent the appearance of bubbles, and change the flow rate of the immersion liquid outlet 3 to 2 ml / min, so that the fluid flows out of the flow field slowly but completely until there is no residual fluid on the surface of the substrate 5, turn off the microinjection pump, and complete the complete removal of the immersion boundary flow field.

[0036] The method of the present invention is a method for recovering an organic medium with low cost and convenient operation. It is known that reducing the wavelength of the exposure light source, increasing the numerical aperture of the projection lens or reducing the process factor can improve the resolution of the photolithography machine. According to the simulation analysis of the flow field, most of the organic media that are difficult to recover remain at the boundary of the substrate 5. Therefore, it is necessary to start with improving the oleophobicity of the material surface, spray a layer of transparent super oleophobic coating on the insufficiently recovered part of the substrate 5, and improve the flow of the organic medium on the substrate 5. During the spraying process, the insufficiently recovered part of the substrate 5 is sprayed, and not all of it is sprayed. The residual organic medium exists at the boundary of the substrate 5, and there is very little residue in the center, and in order to ensure the exposure quality of the core exposure area, the middle part is not sprayed.

[0037] like Figure 4 As shown in (a), when there is no boundary layer coating, the organic medium is difficult to recover, such as Figure 4 As shown in (b), the presence of a boundary layer coating can improve the recovery rate and prevent the medium from being retained in the dead zone and causing pollution.

[0038] Matters not covered in the present invention are known technologies. The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for converging and removing the immersion boundary flow field of an IC lithography device based on organic medium, characterized in that: include: S1: spraying the super oleophobic coating uniformly on the substrate (5) of the IC lithography equipment where the immersion liquid is not fully recovered, forming a layer of transparent super oleophobic film after the spraying is completed, and performing a heating treatment; S2: injecting the immersion liquid (4) into the immersion liquid inlet (2) of the IC lithography equipment at a certain injection speed through the immersion supply system to fill the immersion boundary flow field in the IC lithography equipment and complete the convergence of the immersion boundary flow field; and at the same time, the immersion liquid (4) flows out from the immersion liquid outlet (3) of the IC lithography equipment at a certain recovery speed for recovery; S3: controlling the immersion supply system to stop injecting the immersion liquid (4), causing the immersion liquid (4) to flow out from the immersion liquid outlet (3) of the IC lithography equipment, and recovering the immersion liquid (4) through the immersion supply system until the immersion liquid (4) completely flows out, and no immersion liquid (4) exists at the place where the immersion liquid is not fully recovered, thereby completing the removal of the immersion boundary flow field; In the step S1, an immersion liquid (4) is injected into an immersion liquid inlet (2) of an IC lithography device, and the immersion liquid (4) flows out from an immersion liquid outlet (3) of the IC lithography device. After the injection of the immersion liquid (4) stops, the immersion liquid (4) flows out until it stops flowing out, and the position where the immersion liquid (4) exists on the substrate (5) of the IC lithography device is regarded as a position where the immersion liquid is insufficiently recovered; In the step S1, the super oleophobic coating adopts a fluorine-silicon modified silica solution; In the step S1, the contact angle between the position of the substrate (5) where the transparent superoleophobic film is located and the injected immersion liquid (4) is greater than 140°; In the step S2, the injection speed and the recovery speed are both 5-6 ml / min.

2. The method for converging and removing the immersion boundary flow field of IC lithography equipment based on organic medium according to claim 1, characterized in that: In the step S1, the heating treatment is specifically to bake the substrate (5) of the IC lithography equipment in an oven at 90-110° C. for 10 minutes.

3. The method for converging and removing the immersion boundary flow field of IC lithography equipment based on organic medium according to claim 1, characterized in that: In the step S2, the immersion supply system comprises two micro-injection pumps, which are respectively installed at the immersion liquid inlet (2) and the immersion liquid outlet (3) of the IC lithography equipment.

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