CN113138539B - An immersion liquid supply and recovery device for an immersion lithography machine - Google Patents

Abstract

The invention discloses an immersion liquid supply and recovery device for an immersion lithography machine. The device package includes an immersion liquid supply channel, an immersion liquid recovery channel and an extraction opening, and a pinning tape is arranged between adjacent extraction openings; the pinning tape has an inner pinning tape and an outer pinning tape, which are respectively limited The meniscus retreats inward and advances outward, which can improve the sealing ability of the immersion flow field, improve the vibration characteristics of the immersion liquid recovery channel, and improve the quality of substrate exposure.

Description

An immersion liquid supply and recovery device for an immersion lithography machine

technical field

The invention relates to the technical field of lithography machines, in particular to an immersion liquid supply and recovery device for an immersion lithography machine.

Background technique

The lithography machine is one of the core equipment for the manufacture of ultra-large-scale integrated circuits. The modern lithography machine is mainly based on optical lithography. It uses the optical system to accurately project and expose the pattern on the mask on the photoresist-coated liner. bottom. It includes a laser light source, a projection objective lens system, a projection mask composed of chip patterns, an alignment system and a substrate coated with photosensitive photoresist.

Compared with the dry lithography machine in which the intermediate medium is gas, the immersion lithography (Immersion Lithography) equipment fills a certain high refractive index liquid between the last projection objective lens and the substrate, and improves the refraction of the liquid medium in the gap. ratio (n) to increase the numerical aperture (NA) of the projection objective, thereby increasing the resolution and depth of focus of the lithographic apparatus. Among the current mainstream lithography technologies, immersion lithography has minimal changes to existing equipment, and has good inheritance to current dry lithography machines, so it has received widespread attention. For the filling of the immersion liquid, the widely used solution is partial immersion, that is, the liquid is confined in the local area between the lower surface of the last projection objective and the upper surface of the substrate using the immersion liquid supply and recovery device. Maintaining the optical consistency and transparency of the immersion liquid in the exposure area is the key to ensuring the quality of immersion lithography exposures. For this reason, the existing technical solutions often realize real-time update of the immersion flow field through liquid injection and recovery, and take photochemical pollutants, local heat, micro-nano bubbles, etc. away from the core exposure area in time to ensure high purity and uniformity of the immersion liquid.

As shown in FIG. 1 , the immersion liquid supply and recovery device 2 in the immersion lithography machine is arranged between the projection objective lens system 1 and the substrate 3 , and the immersion liquid is powered by the immersion liquid supply system 5 and injected through the immersion liquid supply and recovery device 2 The space between the projection objective system 1 and the substrate 3 and is pumped by the immersion liquid recovery system 6 via the immersion liquid supply recovery device 2 . The immersion liquid fills the space between the projection objective system 1 and the substrate 3 to form an immersion flow field 4 . The refractive index of the immersion liquid is greater than that of air. Compared with the dry lithography machine, due to the existence of the immersion flow field 4, the refractive index of the optical path medium between the projection objective lens system 1 and the substrate 3 in the immersion lithography machine is increased, and the integrated circuit is carried. After the laser beam of the graphic information passes through the projection objective lens system 1 and the immersion flow field 4 , an integrated circuit pattern with a smaller size can be formed on the substrate 3 .

As shown in FIG. 2 and FIG. 3 , the center of the immersion liquid supply and recovery device 2 has a circular through hole 21 allowing the laser light to pass through, and the circular through hole 21 has a truncated truncated shape adapted to the shape of the lower end surface of the projection objective lens system 1 . The immersion liquid supply and recovery device 2 is provided with an immersion liquid supply channel 22 and an immersion liquid recovery channel 23. The immersion liquid provided by the immersion liquid supply system 5 flows through the immersion liquid supply channel 22 into the immersion flow field 4, and then passes through the immersion liquid recovery channel 23. It is pumped out by the immersion liquid recovery system 6 . There is a gap with a minimum thickness in the range of 0.1 mm to 1 mm between the immersion liquid supply and recovery device 2 and the substrate 3 . In order to prevent the immersion liquid from leaking from the gap to the surrounding environment, the immersion liquid supply system 5 is arranged on the lower end face of the immersion liquid supply system 5 along the axial direction of the circular through hole 21 with a suction opening 24 with a degree ranging from 0.2 mm to 2 mm. One end of the suction opening 24 It communicates with the immersion flow field 4 , and the other end communicates with the extraction cavity 25 . The extraction cavity 25 is an annular cavity, which communicates with the plurality of extraction openings 24 and communicates with the sealed extraction channel 26 . The immersion liquid recovery system 6 applies negative pressure, so that the immersion liquid in the immersion flow field 4 is collected into the suction cavity 25 through the suction opening 24 , and then recovered by the immersion liquid recovery system 6 through the sealed suction channel 26 . Due to the pumping action of the immersion liquid recovery system 6 , the immersion liquid and the surrounding gas form a circle of meniscus 41 near the suction opening 24 . In order to avoid the immersion liquid leaking from the immersion flow field 4 and remaining on the substrate 3 to cause contamination, and to prevent the immersion liquid from retreating too much inward to cause air bubbles to be drawn into the immersion flow field 4, it is necessary to control the position and shape of the meniscus 41 Stablize. Preferably, the meniscus 41 is always kept in contact with the suction opening 24 to ensure that the liquid flow and the gas flow exist in the suction opening 24 at the same time, so as to avoid droplet splashing in the gas flow with large vibration impact or gas bubbling in the liquid flow In this case, the vibration characteristics of the immersion liquid supply and recovery device 2 can be improved.

The projection objective lens system and the immersion liquid supply and recovery device of the immersion lithography machine are fixed, and in the process of exposing the substrate, the substrate needs to be moved so that the integrated circuit pattern is completely formed on the substrate. There is a gap between the immersion liquid supply and recovery device and the substrate, and the end face of the immersion liquid supply and recovery device facing the substrate is provided with a suction opening, which is used to constrain the immersion liquid between the end face of the immersion liquid supply and recovery device and the substrate. It will leave a large area on the substrate and cause contamination. The speed at which the immersion lithography machine moves the substrate directly affects its yield and is the main indicator for measuring the performance of the lithography machine. However, relative movement of the substrate with respect to the immersion liquid supply and recovery device will result in a directional pull on the immersion flow field. In the process of high-speed movement of the substrate, the influence of this pulling motion is obvious, which may lead to the failure of the immersion liquid seal and the leakage of the immersion liquid; it may cause air bubbles to be involved in the immersion liquid, affecting the exposure light path; or the immersion liquid recovery channel The flow pattern of the gas-liquid two-phase flow changes, resulting in changes in its vibration characteristics and thermal conduction characteristics, which ultimately affect the exposure quality.

SUMMARY OF THE INVENTION

Immersion liquid supply and recovery devices often have a plurality of discrete extraction openings, and the area between adjacent extraction openings is relatively weak in confining the immersion liquid. In order to enhance the confinement ability of the immersion liquid in the area between the adjacent suction openings, the present invention provides an immersion liquid supply and recovery device for an immersion lithography machine, by arranging between two adjacent suction openings Pinning tape, which increases the confinement of the meniscus of the immersion flow field moving radially outward and inward in this area, thereby enhancing the confinement ability of the immersion liquid supply and recovery device to the immersion liquid, avoiding the leakage of the immersion liquid onto the substrate or Air bubbles are involved in the immersion flow field.

The technical scheme adopted in the present invention is as follows:

The present invention includes a main body, a vertical liquid injection port, an extraction cavity, a gas injection port, a plurality of extraction openings, and a pinning band, wherein the plurality of extraction openings are located on the side of the main body facing the substrate, between adjacent extraction openings. A pinning tape is provided; the pinning tape has an inner pinning tape and an outer pinning tape, and the inner pinning tape is arranged on the radially outer side of the immersion liquid supply and recovery device relative to the outer pinning tape.

Preferably, the inner pinning strip is sharp-edged and the height of the radially inner surface from the substrate is greater than the height of the radially outer surface from the substrate.

Preferably, the outer pinning band is sharp-edged and the height of the radially inner surface from the substrate is less than the height of the radially outer surface from the substrate.

Preferably, the inner pinning band is a surface whose height from the substrate decreases radially outward.

Preferably, the outer pinning band is a surface that increases in height from the substrate radially outward.

Preferably, the projection of the inner pinning band on the distribution end surface of the extraction opening is a curve with a negative radius of curvature.

Preferably, the projection of the outer pinning tape on the distribution end surface of the extraction opening is a curve with a positive radius of curvature.

Preferably, the height of the pinning band from the substrate decreases from the proximal end to the distal end along the extraction opening.

Preferably, the height of the pinning tape protruding from the distribution end surface of the extraction opening is one tenth to one half of the height of the distribution end surface of the extraction opening from the substrate.

The beneficial effects that the present invention has are:

(1) In the present invention, a pinning tape is provided between adjacent extraction openings, the pinning tape has at least two pinning features, and the pinning tape has an outer pinning tape and an inner pinning tape; the outer pinning tape The tape has a pinning effect on the contact line moving radially outward, which can prevent the immersion liquid from leaking out; the inner pinning tape has a pinning effect on the contact line moving radially inward, and can prevent the immersion liquid from leaking out. Excessive back-back causes air bubbles to become involved in the immersion flow field.

(2) The pinning tape constrains the meniscus so that it is always connected to the suction opening, which is conducive to guiding the immersion liquid into the suction opening; at the same time, it avoids accidental pure liquid phase flow or pure gas flow in the suction opening, and improves the immersion liquid flow. Vibration characteristics of the feed recovery device.

Description of drawings

Fig. 1 is the simplified schematic diagram that the immersion liquid supply recovery device is assembled with the projection objective lens system and the substrate;

Fig. 2 is the schematic diagram of the working principle of the immersion liquid supply and recovery device;

Fig. 3 is the bottom view schematic diagram of Fig. 2;

4 is a schematic diagram of the working principle of the present invention;

Fig. 5 is the bottom view schematic diagram of Fig. 4;

6 is a three-dimensional schematic diagram of a pinning tape;

7 is a schematic diagram of the pinning effect of the contact line;

Figure 8 is a schematic diagram of the working principle of the pinning tape;

Figure 9 shows two other embodiments of the pinning tape;

Figure 10 is another embodiment of the pinning tape;

Figure 11 is another embodiment of the pinning tape;

Figure 12 is a dimensional schematic view of the pinning tape.

Detailed ways

4 to 6 show an embodiment of the immersion liquid supply and recovery device 2 according to the present invention. For the sake of simplicity, FIG. 4 only shows a cross section of one side of the immersion liquid supply and recovery device 2 . The immersion liquid supply and recovery device is provided with a vertical liquid injection port 28 on the radially inner side of the pumping opening 24 to supply the immersion liquid in the direction toward the substrate 3 to prevent the meniscus 41 from retreating to the inner side of the circular through hole 21 to interfere with the laser light path; A gas injection port 29 is provided on the radially outer side of the extraction opening 24 to provide a positive pressure gas flow to the periphery of the submerged flow field 4 to assist in constraining the meniscus 41 . A pinning tape 27 is disposed between two adjacent extraction openings 24 . In this embodiment, the structure of the pinning tape 27 protrudes from the boss of the lower end surface 270 of the main body of the immersion liquid supply and recovery device 2 . The pinning strips 27 between all the extraction openings 24 form an interrupted annular structure. The sharp edge of the lower end surface of the pinning tape 27 located on the radially inner side is the inner pinning tape 271, and the sharp edge located on the radially outer side is the outer pinning tape 272; in addition, the vertical sharp edge of the pinning tape 27 is the vertical pinning tape Band 273.

两个端面的交界线称之为钉扎线200。弯液面41在上游端面201上向前移动，弯液面41与上游端面201的夹角称为前进接触角θ_a，对于一组固体表面和液体组合，前进接触角θ_a是定值。当弯液面41到达钉扎线200时，由于弯液面41与下游端面202之间的夹角小于前进接触角θ_a，接触线410将停止前进，直到弯液面41在驱动力的作用下继续变形使其与下游端面202之间的夹角达到前进接触角θ_a。当弯液面41与上游端面201之间的接触角在θ_a到

范围内时，接触线410将停留在钉扎线200上，这种现象称之为接触线钉扎效应。相似地，当弯液面41从下游端面202后退至上游端面201的途中，在钉扎线200出也会出现类似现象，不过此时钉扎效应成立的弯液面41与上游端面201之间的接触角范围为θ_s到

其中θ_s是后退接触角。接触线钉扎效应限制了接触线410的移动，从而对弯液面41的运动产生了阻碍效果。Figure 7 illustrates the contact line pinning effect. The upstream end face 201 and the downstream end face 202 form an included angle with each other

The boundary line between the two end faces is called the pinning line 200 . The meniscus 41 moves forward on the upstream end surface 201, and the angle between the meniscus 41 and the upstream end surface 201 is called the advancing contact angle θ _a . For a set of solid surface and liquid combinations, the advancing contact angle θ _a is a constant value. When the meniscus 41 reaches the pinning line 200, since the angle between the meniscus 41 and the downstream end face 202 is smaller than the advancing contact angle θ _a , the contact line 410 will stop advancing until the meniscus 41 acts on the driving force Continue to deform downward so that the angle between it and the downstream end face 202 reaches the advancing contact angle θ _a . When the contact angle between the meniscus 41 and the upstream end face 201 is between θ _a and

When the contact line 410 is within the range, the contact line 410 will stay on the pinning line 200, and this phenomenon is called the contact line pinning effect. Similarly, when the meniscus 41 retreats from the downstream end face 202 to the upstream end face 201 , a similar phenomenon occurs when the pinning line 200 exits, but at this time, the pinning effect is established between the meniscus 41 and the upstream end face 201 . The contact angle ranges from θ _s to

where _θs is the receding contact angle. The contact wire pinning effect restricts the movement of the contact wire 410 , thereby creating a blocking effect on the movement of the meniscus 41 .

The working principle of the pinning tape 27 is explained with reference to FIGS. 6 and 8 . As shown in FIG. 8( a ), the meniscus 41 forms an upper contact line 411 with the lower end surface 270 of the immersion liquid supply device 2 , and forms a lower contact line 412 with the surface of the substrate. When the substrate 3 pulls the meniscus 41 in a radially outward direction, the upper contact line 411 will be pinned at the outer pinning band 272, preventing the meniscus 41 from continuing to advance; as shown in FIG. 8(b) As shown, when the substrate 3 pulls the meniscus 41 inward in the opposite radial direction, the upper contact line 411 will be pinned at the inner pinning band 271, preventing the meniscus 41 from continuing to retreat. In fact, pinning may also occur at the outer pinning band 272 when the upper contact line 411 retreats, but the meniscus 41 is curved. In order to avoid the curved surface of the meniscus 41 as shown in FIG. 8(c) contacting first The pinning phenomenon cannot be formed due to the outer pinning tape 272, and the inner pinning tape 271 needs to be provided to further ensure that the meniscus 41 is pinned during the retreating process.

FIG. 9 shows two other embodiments of the pinning tape 27 . One embodiment is shown in FIG. 9( a ), using an inclined surface instead of a sharp edge to pin the contact line, the height of the inner pinning slope 275 from the substrate 3 gradually decreases in the radially outward direction, and the outer pinning slope 275 gradually decreases. The height of the slope 276 from the substrate 3 gradually increases in the radially outward direction. Since the increased surface area of the meniscus 41 requires additional driving force, when the upper contact wire 411 retreats on the inner pinning ramp 275, or the upper contact wire 411 advances on the outer pinning ramp 276, the meniscus 41 will Will be hindered by a pinning effect similar to the contact wire. In addition, a sharp edge type pinning rib 274 is formed between the inner pinning slope 275 and the outer pinning slope 276 , which can have a pinning effect on the upper contact line 411 . The inner pinning tape 271 and the outer pinning tape 272 in Fig. 8 have fixed pinning positions for the contact line, while the inner pinning ramp 275 and the outer pinning ramp 276 in Fig. 9(a) pin the contact line The position is a range, which can reduce the stretching of the meniscus 41 while hindering the movement of the meniscus 41 , thereby helping to enhance the stability of the meniscus 41 . In the embodiment shown in FIG. 9( b ), an inner pinning tape 271 , an outer pinning tape 272 , an inner pinning slope 275 and an outer pinning slope 276 are provided. Using this solution, it is desirable to control the upper contact line 411 as much as possible. Between the inner pinning strip 271 and the outer pinning strip 272, the inner pinning slope 275 and the outer pinning slope 276 prevent the meniscus from being overstretched during retreat and advance, respectively, and the slope of the inner pinning slope 275 is gentle. At the outer pinning slope 276, it is desirable to further alleviate the stretching effect that the meniscus 41 experiences as it advances.

As shown in FIG. 10( a ), the inner pinning band 271 and the outer pinning band 272 may be a set of straight lines or arcs that are parallel to each other. Considering that the pumping capacity between the two pumping openings 24 is weak, the meniscus will show a convex arc with a positive radius of curvature when it moves radially outward, and it will show a negative curve when it moves radially inward. The concave arc of the radius of curvature. As shown in FIG. 10(b), the inner pinning tape 271 and the outer pinning tape 272 are respectively designed as curves with negative and positive curvature radii, which can adapt to the deformation of the meniscus and improve the force of the meniscus , to enhance its stability.

As shown in FIG. 11( a ), the inner (outer) pinning tapes 271 ( 272 ) can be arranged in a plane parallel to the plane curve of the substrate 3 . Considering that the extraction ability is weak at a position far from the extraction opening 24, the inner (outer) pinning tape 271 (272) can be set to the height from the substrate shown in FIG. 11(b) from the proximal end of the extraction opening. The reduced curvilinear shape to the distal end reduces the flow resistance to the lateral flow of the fluid, which can facilitate the convergence of the immersion liquid flow to the vicinity of the extraction opening 24 .

As shown in FIG. 12, the maximum height h1 of the inner (outer) pinning tape 271 (272) protruding from the lower end surface 270 is taken as one tenth to one half of the height h2 of the lower end surface 270 from the substrate 3. better settings. If the value of the height h1 is too small, the pinning of the inner (outer) pinning tape 271 (272) to the contact line will easily fail due to random disturbance; if the value of the height h1 is too large, the inner (outer) pinning tape 271 (272) The risk of scratching against the substrate 3 is too great.

The above-mentioned specific embodiments are used to explain the present invention, rather than to limit the present invention. Within the protection scope of the claims of the present invention, any modifications and changes made to the present invention all fall into the protection scope of the present invention.

Claims (9)

1. The utility model provides a recovery unit is supplied with to immersion fluid for submergence formula lithography machine, includes the main part, annotates liquid mouth, pump drainage chamber, gas injection mouth, a plurality of pump drainage openings and nail ribbon perpendicularly, its characterized in that: the pumping openings are positioned on one surface of the main body facing the substrate, and a binding belt is arranged between every two adjacent pumping openings; the nail tying belt is provided with an inner nail tying belt and an outer nail tying belt, and the inner nail tying belt is arranged on the radial outer side of the immersion liquid supply and recovery device relative to the outer nail tying belt; the outer pinning band hinders the meniscus to move radially outward, and the inner pinning band hinders the meniscus to move radially inward.

2. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to claim 1, wherein: the inner pinning strip is a sharp edge and has a radially inner surface at a greater height from the substrate than a radially outer surface.

3. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to claim 1, wherein: the outer staple band is a sharp edge and has a radially inner surface that is less in height from the substrate than a radially outer surface.

4. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to claim 1, wherein: the inner pinning strip is a surface that decreases in height radially outward from the substrate.

5. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to claim 1, wherein: the outer staple band is a surface that increases in height radially outward from the substrate.

6. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to any one of claims 1 to 5, wherein: the projection of the inner pinning strip on the distribution end face of the pumping opening is a curve with a negative curvature radius.

7. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to any one of claims 1 to 5, wherein: the projection of the outer pinning strip on the distribution end face of the pumping opening is a curve with a positive curvature radius.

8. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to any one of claims 1 to 5, wherein: the height of the pinning strip from the substrate decreases from the proximal end to the distal end along the pumping opening.

9. An immersion liquid supply and recovery apparatus for an immersion lithography machine according to any one of claims 1 to 5, wherein: the height of the nail ribbon protruding out of the distribution end face of the pumping opening is one tenth to one half of the height of the distribution end face of the pumping opening from the substrate.

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