CN113138539B

CN113138539B - Immersion liquid supply and recovery device for immersion lithography machine

Info

Publication number: CN113138539B
Application number: CN202010055886.5A
Authority: CN
Inventors: 付新; 王晓波; 吴敏; 苏芮; 胡亮
Original assignee: Zhejiang Cheer Technology Co ltd; Zhejiang University ZJU
Current assignee: Zhejiang Cheer Technology Co ltd; Zhejiang University ZJU
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2022-04-26
Anticipated expiration: 2040-01-17
Also published as: CN113138539A

Abstract

The invention discloses an immersion liquid supply and recovery device for an immersion lithography machine. The device bag comprises an immersion liquid supply channel, an immersion liquid recovery channel and pumping and discharging openings, and a binding belt is arranged between every two adjacent pumping and discharging openings; the nail ribbon has interior nail ribbon and outer nail ribbon, restricts the inward retreat of meniscus and outwards gos forward respectively, can improve the sealing capability in submergence flow field, improves the vibration characteristic of immersion fluid recovery passageway, improves the quality of substrate exposure.

Description

Immersion liquid supply and recovery device for immersion lithography machine

Technical Field

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

Background

One of the core equipments for manufacturing very large scale integrated circuits is a lithography machine, which is based on optical lithography and uses an optical system to precisely project and expose a pattern on a reticle onto a substrate coated with a photoresist. The device comprises a laser light source, a projection objective system, a projection mask plate consisting of chip patterns, an alignment system and a substrate coated with photosensitive photoresist.

In contrast to a dry Lithography machine in which the intermediate medium is a gas, an Immersion Lithography (Immersion Lithography) apparatus increases the Numerical Aperture (NA) of the projection objective by filling a certain high refractive index liquid between the final projection objective and the substrate, and by increasing the refractive index (n) of the gap liquid medium, thereby increasing the resolution and depth of focus of the Lithography apparatus. In the mainstream lithography technology, immersion lithography has received much attention because it has minimal modification to existing equipment and has good inheritance to current dry lithography machines. For the filling of immersion liquid, a solution which is widely used at present is partial immersion, i.e. the use of an immersion liquid supply and recovery device for confining liquid in a partial region between the lower surface of the final projection objective and the upper surface of the substrate. Maintaining the optical consistency and transparency of the immersion liquid in the exposure area is a key to ensuring the quality of immersion lithography exposure. Therefore, in the prior art, the immersion flow field is usually updated in real time through liquid injection and recovery, and photochemical pollutants, local heat, micro-nano bubbles and the like are timely brought away from the core exposure area, so that the high purity and uniformity of immersion liquid are ensured.

As shown in fig. 1, in an immersion lithography machine, an immersion liquid supply and recovery device 2 is arranged between a projection objective system 1 and a substrate 3, and immersion liquid is supplied with power by an immersion liquid supply system 5, injected into a space between the projection objective system 1 and the substrate 3 via the immersion liquid supply and recovery device 2, and pumped out by an immersion liquid recovery system 6 via the immersion liquid supply and recovery device 2. The immersion liquid fills the space between the projection objective system 1 and the substrate 3 forming an immersion flow field 4. The refractive index of the immersion liquid is larger than that of air, compared with a dry-type photoetching machine, due to the existence of the immersion flow field 4, the refractive index of an optical path medium between the projection objective system 1 and the substrate 3 in the immersion-type photoetching machine is improved, and the laser beam carrying the integrated circuit pattern information can form an integrated circuit pattern with a smaller size on the substrate 3 after passing through the projection objective system 1 and the immersion flow field 4.

As shown in fig. 2 and 3, the immersion liquid supply and recovery device 2 has a circular through hole 21 at the center thereof for allowing passage of the laser light, and the circular through hole 21 has a circular truncated cone shape with a large top and a small bottom that is adapted to the shape of the lower end surface of the projection objective system 1. An immersion liquid supply channel 22 and an immersion liquid recovery channel 23 are provided in the immersion liquid supply and recovery device 2, and immersion liquid supplied by the immersion liquid supply system 5 flows through the immersion liquid supply channel 22 into the immersion flow field 4 and is pumped out by the immersion liquid recovery system 6 through the immersion liquid recovery channel 23. A gap having a minimum thickness in the range of 0.1mm to 1mm exists between the immersion liquid supply and recovery apparatus 2 and the substrate 3. In order to avoid the immersion liquid from leaking to the surrounding environment from the gap, the immersion liquid supply system 5 is provided with a pumping opening 24 with the linear degree within the range of 0.2 mm-2 mm on the lower end surface along the axial direction of the circular through hole 21, one end of the pumping opening 24 is communicated with the immersion flow field 4, and the other end is communicated with the pumping cavity 25. The pumping chamber 25 is a circular ring-shaped chamber body which communicates with the plurality of pumping openings 24 and with the sealed pumping channel 26. The immersion liquid recovery system 6 applies a negative pressure such that immersion liquid in the immersion flow field 4 converges through the pumping opening 24 into the pumping chamber 25 and is then recovered by the immersion liquid recovery system 6 through the sealed pumping channel 26. Due to the pumping action of the immersion liquid recovery system 6, the immersion liquid and the ambient gas form a ring of meniscuses 41 near the pumping openings 24. In order to avoid contamination of the immersion liquid leaking from the immersion flow field 4 and remaining on the substrate 3, and to avoid bubble entrainment in the immersion flow field 4 due to excessive inward withdrawal of the immersion liquid, it is necessary to control the position and shape of the meniscus 41 to be stable. Preferably, the meniscus 41 is always kept in contact with the pumping opening 24, so that the liquid flow and the gas flow are always simultaneously present in the pumping opening 24, the splash of liquid droplets in the gas flow with large vibration impact or the bubbling of gas in the liquid flow is avoided, and the vibration characteristics of the immersion liquid supply and recovery device 2 can be improved.

The projection objective system and the immersion liquid supply and recovery device of an immersion lithography machine are stationary and during exposure of the substrate, the substrate needs to be moved to complete the formation of the integrated circuit pattern on the substrate. A gap exists between the immersion liquid supply and recovery device and the substrate, and a pumping and exhausting opening is arranged on the end face, facing the substrate, of the immersion liquid supply and recovery device and used for restraining immersion liquid between the substrate and the end face of the immersion liquid supply and recovery device, so that large-area residual on the substrate cannot cause pollution. The speed of the substrate moving in the immersion lithography machine directly affects the productivity, and is a main index for measuring the performance of the lithography machine. But relative movement of the substrate with respect to the immersion liquid supply and recovery means will result in the immersion flow fields being directionally pulled. During high speed movement of the substrate, the effects of this pulling motion are significant, and can lead to failure of the immersion liquid seal, leakage of the immersion liquid; bubbles may be entrained in the immersion liquid, affecting the exposure light path; or the flow pattern of the gas-liquid two-phase flow in the immersion liquid recovery channel is changed, so that the vibration characteristic and the heat conduction characteristic of the immersion liquid recovery channel are changed, and the exposure quality is finally influenced.

Disclosure of Invention

Immersion liquid supply and recovery devices often have a plurality of discrete extraction openings, with the regions between adjacent extraction openings being relatively weak to the immersion liquid. In order to enhance the constraint capacity of immersion liquid in the area between adjacent pumping openings, the invention provides an immersion liquid supply and recovery device for an immersion lithography machine, which increases the constraint of the area on the meniscus of an immersion flow field moving outwards and inwards in the radial direction by arranging a pinning belt between two adjacent pumping openings, thereby enhancing the constraint capacity of the immersion liquid supply and recovery device on the immersion liquid and avoiding the immersion liquid from leaking onto a substrate or bubbles from being involved in the immersion flow field.

The technical scheme adopted by the invention is as follows:

the invention comprises a main body, a vertical liquid injection port, a pumping cavity, a gas injection port, a plurality of pumping openings and a pinning band, wherein the plurality of pumping openings are positioned on one surface of the main body facing to a substrate, and the pinning band is arranged between the adjacent pumping openings; the pinning band has an inner pinning band and an outer pinning band, the inner pinning band is disposed radially outward of the immersion fluid supply and recovery device relative to the outer pinning band.

Preferably, 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.

Preferably, the outer pinning strip is a sharp edge and has a radially inner surface that is less in height from the substrate than a radially outer surface.

Preferably, the inner pinning strip is a surface that decreases in height radially outward from the substrate.

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

Preferably, the projection of the inner pinning strip on the end face of the distribution of the pumping openings is a curve with a negative radius of curvature.

Preferably, the projection of the outer pinning strip on the end face of the pumping opening distribution is a curve with a positive radius of curvature.

Preferably, the height of the staple ties from the substrate decreases from the proximal end to the distal end along the evacuation opening.

Preferably, the height of the nail tying belt protruding from 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.

The invention has the beneficial effects that:

(1) according to the invention, a nail tying belt is arranged between adjacent pumping and discharging openings, the nail tying belt has at least two nail tying characteristics, and the nail tying belt is provided with an outer nail tying belt and an inner nail tying belt; the outer nailing and binding belt has a nailing effect on a contact line moving outwards along the radial direction, and can prevent the immersion liquid from leaking outwards; the inner pinning strip has a pinning effect on a contact line moving inwards along the radial direction, and can prevent immersion liquid from excessively retreating inwards to cause bubbles to be drawn into an immersion flow field.

(2) The pinning band restrains the meniscus to be always connected with the pumping opening, so that the immersion liquid is guided to flow into the pumping opening; meanwhile, accidental pure liquid phase flow or pure gas phase flow in the pumping opening is avoided, and the vibration characteristic of the immersion liquid supply and recovery device is improved.

Drawings

FIG. 1 is a simplified schematic illustration of an immersion liquid supply and recovery device in assembly with a projection objective system and a substrate;

FIG. 2 is a schematic view showing the operation of the immersion liquid supply and recovery apparatus;

FIG. 3 is a schematic bottom view of FIG. 2;

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

FIG. 5 is a schematic bottom view of FIG. 4;

FIG. 6 is a three-dimensional schematic view of a staple tie;

FIG. 7 is a schematic view of contact line pinning effect;

FIG. 8 is a schematic view of the operating principle of the pinning strip;

FIG. 9 is two additional embodiments of a pinning strip;

FIG. 10 is another embodiment of a staple tie;

FIG. 11 is another embodiment of a pinning strip;

FIG. 12 is a dimensional schematic of a staple tie.

Detailed Description

Fig. 4 to 6 show an embodiment of the immersion liquid supply and recovery apparatus 2 according to the present invention. For the sake of simplicity, fig. 4 shows only 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 radial inner side of the pumping opening 24 to supply the immersion liquid in the direction toward the substrate 3 and 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 radially outward of the pumping port 24 to provide a positive pressure gas flow to the periphery of the submerged flow field 4 to assist in confining the meniscus 41. Between two adjacent evacuation openings 24, a staple band 27 is arranged, which staple band 27 in this embodiment has a design that protrudes over a projection of the lower end face 270 of the main body of the immersion liquid supply and recovery device 2. The pinning strips 27 between all of the extraction openings 24 form an interrupted loop structure. The sharp edge of the lower end face of the pinning band 27 located on the radially inner side is an inner pinning band 271, and the sharp edge located on the radially outer side is an outer pinning band 272; additionally, the vertical sharp edge of the staple band 27 is a vertical staple band 273.

Fig. 7 explains the contact line pinning effect. The upstream end face 201 and the downstream end face 202 are at an angle to each other

The line of intersection of the two end faces is referred to as the staple line 200. The meniscus 41 moves forward on the upstream face 201, and the angle between the meniscus 41 and the upstream face 201 is referred to as the advancing contact angle θ_aAdvancing contact Angle θ for a set of solid surface and liquid combinations_aIs a constant value. When the meniscus 41 reaches the pinning line 200, the meniscus 41 makes an angle with the downstream end face 202 that is less than the advancing contact angle θ_aThe contact line 410 will stop advancing until the meniscus 41 continues to deform under the driving force to make an angle with the downstream end face 202 reaching the advancing contact angle θ_a. When the contact angle between the meniscus 41 and the upstream end face 201 is at θ_aTo

Within range, the contact wire 410 will rest on the pinning wire 200, a phenomenon known as contact wire pinning. Similarly, as the meniscus 41 recedes from the downstream end face 202 on the way to the upstream end face 201, pinning is providedA similar phenomenon occurs with the line 200, but the range of contact angles between the meniscus 41 and the upstream end face 201 where the pinning effect is established is θ_sTo

Wherein theta is_sIs the receding contact angle. The contact line pinning effect limits the movement of the contact line 410, thereby creating a drag effect on the movement of the meniscus 41.

The working principle of the staple band 27 is explained in connection with fig. 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 apparatus 2 and a lower contact line 412 with the substrate surface. When the substrate 3 pulls the meniscus 41 in a radially outward direction, the upper contact line 411 will generate a pinning phenomenon at the outer pinning band 272, which hinders the meniscus 41 from continuing to advance; as shown in FIG. 8(b), when the substrate 3 pulls the meniscus 41 inward in the opposite radial direction, the upper contact line 411 will cause pinning at the inner pinning band 271, preventing the meniscus 41 from continuing to recede. In fact, the pinning phenomenon may occur at the outer pinning band 272 when the upper contact line 411 retreats, but the meniscus 41 is curved, so as to avoid that the pinning phenomenon cannot be formed because the curved surface of the meniscus 41 first contacts the outer pinning band 272 as shown in fig. 8(c), an inner pinning band 271 needs to be arranged to further ensure that the pinning effect is achieved during the retreating of the meniscus 41.

Fig. 9 shows two further embodiments of the pinning strip 27. One embodiment uses a sloped surface instead of a sharp edge to pin the contact lines, as shown in fig. 9(a), with the inner pinning ramp 275 decreasing in height from the substrate 3 in a radially outward direction and the outer pinning ramp 276 increasing in height from the substrate 3 in a radially outward direction. Since the increased surface area of the meniscus 41 requires the provision of additional driving force, the meniscus 41 will be subject to a retarding effect similar to the contact line pinning effect when the upper contact line 411 is retracted on the inner pinning ramp 275 or the upper contact line 411 is advanced on the outer pinning ramp 276. In addition, a sharp edge type pinning edge 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 and outer

staple ties

271, 272 of fig. 8 have fixed pinning locations to the contact lines, while the inner and outer pinning

ramps

275, 276 of fig. 9(a) have a range of pinning locations to the contact lines that may mitigate stretching of the meniscus 41 while impeding movement of the meniscus 41, helping to enhance the stability of the meniscus 41. In the embodiment shown in fig. 9(b), an inner pinning band 271, an outer pinning band 272, an inner pinning ramp 275, and an outer pinning ramp 276 are provided, and using this approach it is desirable to control the upper contact line 411 as much as possible between the inner pinning band 271 and the outer pinning band 272, the inner pinning ramp 275 and the outer pinning ramp 276 prevent the meniscus from being overstretched when backing and advancing, respectively, and the slope of the inner pinning ramp 275 is slower than the outer pinning ramp 276, which is desirable to further mitigate the stretching effect experienced when the meniscus 41 is advanced.

As shown in fig. 10(a), the inner staple ties 271 and the outer staple ties 272 may be a set of mutually parallel straight or curved lines. Considering the relatively weak pumping capacity in the middle of the two pumping openings 24, the meniscus will exhibit a convex arc with a positive radius of curvature when moving radially outward and a concave arc with a negative radius of curvature when moving radially inward. As shown in fig. 10(b), the inner staple band 271 and the outer staple band 272 are designed to have a negative curvature radius and a positive curvature radius respectively, so as to adapt to the deformation of the meniscus, improve the stress condition of the meniscus, and enhance the stability of the meniscus.

As shown in fig. 11(a), the inner (outer) pinning strips 271(272) may be disposed in a plane parallel to the planar curve of the substrate 3. Considering the weak pumping ability at a position far from the pumping opening 24, the inner (outer) staple bands 271(272) may be arranged in a curved shape as shown in fig. 11(b) in which the height from the substrate decreases from the proximal end to the distal end of the pumping opening, reducing the resistance to lateral flow of fluid, and promoting the flow of immersion liquid to converge near the pumping opening 24.

As shown in fig. 12, it is preferable that the maximum height h1 at which the inner (outer) staple ties 271(272) protrude from the lower end surface 270 is one tenth to one half of the height h2 of the lower end surface 270 from the substrate 3. If the height h1 is too small, the pinning of the inner (outer) pinning strips 271(272) to the contact line is easy to fail due to random disturbance; if the height h1 is too large, the risk of the inner (outer) pinning strips 271(272) scratching the substrate 3 is too great.

The foregoing detailed description is intended to illustrate and not limit the invention, which is defined by the claims, and any modifications and changes made thereto within the scope of the claims.

Claims

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.