A lithography system and a wafer table for supporting a wafer

Lithography system and wafer table for supporting wafer

A LITHOGRAPHY SYSTEM AND A WAFER TABLE FOR SUPPORTING A WAFER

The present invention relates to a lithography system for projecting an image pattern onto the surface of a target (for example, a wafer).

Such a lithography system is generally known from patent WO 2004038509, for example. In the application example represented by the latter system, the target material of the pattern to be formed is subjected to the incidence of photons or charged particles (for example, ions and electrons). In order to achieve high-precision patterning of the target, the target must be firmly bonded or connected to a target stage. Through the action of the target stage, the target moves relative to the incident source, at least It is provided that the position measurement of the target is performed through the target stage. This movement is performed at least substantially in a direction transverse to a main incident direction. During the processing of the target, it is more appropriate to maintain the target at a position opposite to the target stage, for example, when the target is embedded in the position to be processed, or when the target is inserted from the position to be processed. In the process of removing the target material, the relative position of the target material and the target table can be measured as a final processing part. In addition, when the target is embedded in a vacuum environment, or during the process of removing the target from the vacuum environment, the above requirements to be implemented must remain effective. Different solutions exist to meet the above requirements, for example by electromechanical clamping.

The target (usually a wafer) is processed in a modern lithography system at a target conveying mechanism. The target conveying mechanism is usually a suction cup or a wafer table. The target conveying mechanism It is also marked here as the reference element of the target. The reference element (that is, the transport mechanism) is constructed to be very flat to support the target's lithographic exposure process and minimize the target's positioning and/or focus error. So far, it is especially used to avoid and/or prevent bending and warping in the target material. During the exposure process, by applying a force to the target material, the target material is at least maintained at the reference level. The components are in close contact. In this way, the target It also maintains the optimal depth of focus in the lithography system contained in the target. The force is usually a traction force generated by an electrostatic and/or vacuum mechanism acting on the target.

However, this solution has the disadvantage of having to carry pipes, cables and/or wiring together with the target stage. Therefore, it increases the need for high-precision positioning results of the target stage relative to the projection mechanism of a lithography system. the complexity. This shortcoming also occurs in the system where the target material is to be taken out and combined with the target material table. The system provides a coupling and decoupling effect that will then be performed on the cables, wiring and/or conduits.

Other further and important requirements for the lithography system used to form a pattern on a target include achieving the flatness of the target, which is a requirement to eliminate wafer bending and warping. The above requirements This is done by pulling the target to a reference element. The mechanisms used to perform the above functions are generally the same as or limited to those required to perform the function of keeping the target positioned on the target stage within an exposure range.

The mechanisms for maintaining the target in position and/or for pulling the target to a flat reference element can be loaded due to thermal expansion and contraction. This thermal expansion and contraction is due to an energy load of one of the projection systems of the lithography system, which includes the patterning to the wafer.

Therefore, a further requirement for the conventional lithography system is to realize a heat conduction effect between the target and the target table. In fact, it is about conducting heat from the target toward a heat dissipation part of the lithography system. The rapid conduction and dissipation of such heat limits the positioning distortion caused by the thermal expansion or contraction of the target material. The above thermal expansion or contraction phenomenon is particularly important in the existing lithography system. In modern lithography systems, it is necessary to achieve high productivity. For example, in terms of wafer production per hour, the target can withstand a relatively high energy. Load, the high-energy load is usually converted into heat, and can cause positioning distortions if not resolved.

The heat dissipation effect can be satisfied by the heat dissipation mechanism, and how to transfer the heat of the target material toward the heat dissipation mechanism is still a limiting factor in any solution intended to overcome the heat dissipation condition. Therefore, a further object of the present invention is to realize a clamping method and a clamping mechanism to optimally satisfy the problem of heat conduction, while maintaining the actual in-use state, and at the same time, it will be used to transport the target One of the target table or suction cup The distortion of part of the positioning function is reduced to a minimum.

Generally speaking, the positioning of a target (for example, a wafer) on a suction cup is known from a machining procedure, as in patents EP0100648, JP7237066, and JP8064662, in which, before machining the wafer, the crystal The circle is frozen onto a suction cup. According to the invention summary of the latter patent announcement, a wafer is mounted on a wafer mounting surface through a pure water layer with a small thickness. In converting the above conventional concept to an application example of a lithography system, there is a disadvantage with regard to the required positioning accuracy that a pipe must be used to feed the refrigerant through the suction cup.

The previous shortcomings are described in PCT/US01/26772, which discloses a wafer clamp in a lithography system. The wafer clamp is also used to transfer heat guided by a beam of charged particles to a target. The clamping and releasing of the target in the above device is performed by applying "one or more" phase conversion to a clamping element, which is applied to a wafer and a clamping element. Between supporting structures. The above phase conversion is to "help to obtain different operation results in the entire processing procedure" and "ensure that the wafer can be easily loaded and released from the support structure". The clamping element is applied in a liquid form or a gas form, and becomes a solid state by the active cooling effect of the supporting structure, so as to obtain a solid state clamping effect in which the wafer is connected to the supporting structure. The conclusion reached here is that the clamping action is basically expressed as gluing the wafer.

The above-mentioned conventional clamping device used in a lithography system is shown to be "especially useful for processing procedures that require wafer cooling", especially in the vacuum state due to the large contact area between a component and the wafer. And one of the clamping elements has high thermal conductivity. However, in addition to the temperature changes required in the support structure, a disadvantage of the prior art system is that it requires multiple conduits for the clamping element and a circulating cooling fluid to be separately delivered to the target table.

US Patent Publication 2005/0186517 relates to a processing procedure for a lithography system, attaching a wafer to a chuck for aligning a wafer with a wafer stage, and then exposing the wafer. The patent notice specifically tells how to cause relative stress to resist the expansion of the wafer after the initial stress used to alleviate the expansion of a wafer chuck, so before unwanted sliding occurs between the wafer and the chuck , Double the allowable heat of the wafer. The attachment processing procedure is a procedure that uses electrostatic clamping and a procedure that uses vacuum clamping. The procedure used is used as an application example. The attachment processing procedure also requires cables and/or conduits to a movable platform for transporting the target.

In addition to the vacuum environment encountered in the range of target lithography exposure, it comes from the technical field of wafer testing, which was proposed in the Southwestern Test Seminar of the Society of Electrical and Electronic Engineers (SWTW 2005 Seminar) on June 4, 2005 The paper "Liquid Interface for Wafer Testing" was published. According to EP Patent Application 511928 in 1991, we learned how to integrate heat conduction and clamping from a wafer to a suction cup through the action of a flowing water film. The operating principle known in the conventional device is to conduct the heat generated by the target through the water film by maintaining the water film at a very small thickness. However, the minimum thickness is also large enough to transfer the heat from the backside of the wafer. The roughness that is often encountered is leveled. In the operating principle according to the first document, the clamping effect is achieved by conveying the fluid on the top side of a groove-shaped, flat clamping section of a suction cup. In a later document, the groove seems to have been removed from the clamping section, implicitly confirming that the heat is not carried away by the fluid flow. The explanation: "The heat is conducted through the fluid. Flow into the suction cup". In addition, it shows that a wafer is firmly drawn to the water film by the action of a vacuum, and the vacuum action is applied to a liquid film between the suction cup and the wafer, and the recovery in the suction cup The position is positioned on the periphery of the wafer on the suction cup, so the fluid flows in through a central opening.

Since the vacuum environment required for lithography exposure is implemented in modern systems, it is impractical to apply the viewpoints learned from the field of wafer testing to the field of wafer exposure. However, for lithography systems that are not implemented under severe vacuum conditions, one of the disadvantages is that the water flow is usually an undesirable phenomenon, and in particular, the water flow may cause the risk of being blocked by contaminants. . Due to the lack of excess pressure at the top side of the target, the conventional system will fail in an application that requires vacuum operation. The recovery opening requires some vacuum, or a pressure lower than atmospheric pressure, to facilitate the flow of liquid, and the central supply opening for the fluid is presupposed to be a pressure higher than the pressure at the return side. When the system enters a vacuum environment, the target will tend to be lifted from its position rather than clamped.

The present invention here intends to realize a clamping system for the current lithography system, that is, precise relative positioning of the target and the light source with high-precision pixel resolution and high precision. because Therefore, the constraints include a vacuum operable system and the best heat transfer from an exposure target to a target transport mechanism or suction cup. In order to achieve this, the present invention proposes to use a stationary phase liquid film, capillary action is included between the transport mechanism and the target, to perform both the heat conduction function and a clamping function produced by the same liquid mechanism .

Through this novel solution, the cables or conduits and similar pipe fittings that lead from the "fixed" field to a movable target transport mechanism are completely eliminated. Therefore, it is quite comprehensive to reduce the number of cables or pipes and similar pipes in the transport mechanism. Negative effect on positioning accuracy.

Provided that the relevant conditions are appropriately set, the present invention is obviously different from the view that a strong traction force can be applied to a liquid like water, as it was issued by Discover on March 27, 2003 The very general textual description proposed in the article "Negative Pressure Physics". In the application example of the lithography system, it is assumed that if a liquid is maintained and fixed between the surface of a wafer target and the surface of a target transport mechanism or suction cup by capillary action, the above setting values can be achieved For clear reasons, the above surface is usually as flat as possible.

In this type of liquid containing capillary action, in fact a liquid volume between two plates or similar plate structures is used for existing lithography applications. The side effect of the liquid to the surface of the plate results in a surrounding extended liquid surface. It extends between the two flat plates in a concave manner. The concave shape of the liquid surface is intended to maintain its shape, even if tension is applied by pulling the two planes apart, it indicates that negative tension is generated along with the liquid capacity containing capillary action.

According to the present invention, it is further understood that through the liquid containing capillary action, the relatively small amount of the liquid layer prevents the boiling of the liquid (for example, water) from occurring, even when the liquid is under negative pressure. This phenomenon is also the actual value of heat conduction. Therefore, it is envisaged that a liquid under negative pressure can be used to provide the force required to draw a target or wafer to a flat reference element. In other words, as if between the flat plate composed of the reference element and the target, a liquid in a small gap exerts a force on the flat plate composed of the gap. In addition to the height of the gap based on the material properties of the liquid and the plate, the force is applied to maintain a target and a target table as one.

Although in this novel concept, the pressure inside the liquid is less than zero, indicating that the tension exists in the liquid, it is known that when the gap height between the target and the reference element is set Set to be smaller than the critical radius of the vapor bubble under the accompanying liquid pressure, the liquid will not be able to form cavities, that is, it will not be able to boil. Therefore, in this respect, in the fixing liquid containing capillary action described above, it is also known that a liquid similar to water cannot boil. A liquid can generate a considerable clamping force, which is sufficient for use in lithography. Applications.

Obviously, the operating principle invented so far can be applied in different ways.

<p>1Wafer/Target</p><p>2Target table/top surface/top side</p><p>3Contains capillary action liquid/stationary phase liquid layer</p><p>3'Does not contain capillary action liquid</p><p>4Liquid surface/concave surface/liquid/vapor interface</p><p>7Projection part/spacer</p><p>8Wafer table/target transport mechanism/target table</p><p>9O-ring/elastic deformable mechanism</p><p>9AVapor Restriction Ring</p><p>9BVertical distance/minimum gap</p><p>10Groove</p><p>10BOpening</p><p>11Droplets</p><p>12Open</p><p>15Spacer</p><p>AContact surface/material</p><p>BContact surface/material</p><p>CLiquid</p><p>hGap height</p><p>P_capPressure drop</p><p>P_envEnvironmental pressure</p><p>P_liqLiquid pressure</p><p>P_opOver pressure</p><p>P_vacVacuum pressure</p><p>P_capCapillary pressure</p><p>RRadius</p><p>VValve</p><p>θ₁Contact angle</p><p>θ₂Contact angle</p><p>CTClean Wafer Table</p><p>WOTwafer placed on the target table</p><p>LIGLiquid flows into the gap</p><p>CSSealed Conduit</p><p>LOTLiquid is applied on the wafer table</p><p>ITTarget table and wafer embedded lithography system</p><p>PWProcessing Wafer</p><p>RTRemove wafer and target table</p><p>DWSeparation of wafers</p>

The present invention will be further explained through the application examples of the following embodiments of the maskless lithography system according to one of the current invention contents. Among them: Figure 2 shows the capillary pressure drop between a fused silica optical plane and a silicon wafer, and the capillary pressure drop between the two capillary action plates containing water A schematic description of the gap height relationship; Figures 3 and 4 are schematic illustrations of the implementation of the following inventive concept; Figure 5 is a schematic diagram of the first method of introducing liquid into the capillary gap between the target table and the target Description; Figure 6 by providing a peripheral side groove, outline a method for minimizing the amount of liquid evaporated from the capillary gap; Figure 7 is used to achieve a liquid layer between the target and the target A schematic illustration of the implementation method in the middle of the material table; FIG. 8 is a processing flow for a lithography system, in which at least part of the processing flow is in accordance with the present invention; and FIG. 9 is a schematic illustration of the use of spacers.

In the drawings, corresponding structural features (that is, at least functionality) are marked with the same component symbols.

Figure 1 shows a lithographic target, here in the form of a wafer 1. With an activated target table or suction cup (not shown in the figure), the wafer is generally relative to, for example, It is the charged particle beam of a lithography tool, or other types of beam sources used for lithography to move. Between a top side edge of the target table 2 and the target 1, the capacity of a liquid 3 is Has a capillary effect. So far, the target 1 and the top surface 2 have a mutual surface distance of a gap height h. From the above view, the capacity of the liquid (water is more suitable according to the present invention) is such that the radius of the target is almost in line with the radius R of the liquid containing capillary action 3. In any case, the radius of an inscribed circle of the target material at least corresponds to a radius of an circumscribed circle used to install the liquid volume within the boundary of the target material. In fact, the liquid is within the boundary of the target, so it is more appropriate to maintain only a short distance. Therefore, the capillary-containing liquid 3 forms a liquid surface 4, which is additionally labeled as a fluid interface 4 at its outer periphery. Seen according to the cross-section of FIG. 1, since the liquid reaches the target material 1 and a target material, respectively. For the attachment and connection of the side 2 of the top of the table, the fluid interface 4 is usually concave. The concave-shaped surface 4 tends to maintain its shape when the target and the target table are pulled apart, and depends on the pressure difference. The concavity of the interface 4 is based on individual different contact angles θ₁And θ₂, The two contact angle θ₁And θ₂It is followed by the materials of target stage 2 and target 1, in this application example, material A and material B respectively.

In Figure 1, the capillary pressure P_capIt is the pressure drop above the fluid interface 4 at the edge of the volume of the liquid 3. The capillary pressure can be defined by a simplified formula according to the following further description of the present invention:<maths><img he="125" wi="1189" file="TW201351069A_D0001.tif" img-content="drawing" img-format="tif" orientation="portrait" inline="no" /></maths>

in<i>γ</i>_{<i>liquid</i>}Is the surface tension of the liquid [Newton/m], and the contact angle θ₁And θ₂These are the angles at which the liquid/vapor interface 4 touches the materials A and B, respectively. However, if the material properties of the liquid 3 and the solid materials A and B at the location of the interface 4 are not used to make the main decision, the contact angle is an important item. In the same respect, it is also based on the following formula: P_env+P_cap=P_liq (2)

Where P is equal to the environmental pressure

P_capEqual to the capillary pressure in interface 4

P_liquidEqual to the pressure in liquid 3

Combining formula (1) and formula (2), the following results can be obtained: If -P_cap&gt;P_env, Then P_liquid&lt;0 bar (3)

When P_envWhen approaching 0 bar, the latter situation will occur, or when |P_cap | When 1 bar, it is below atmospheric pressure. Because P_liq&lt;0 bar, which means that the pressure in the liquid is negative. Further confirm that when P_liqWhen it is less than the vapor pressure of the liquid, the fluid 3 can then start to boil or form air pockets. However, by making the height of the gap smaller than a critical radius of the bubbles, the boiling phenomenon of the fluid 3 is avoided.

Figure 2 illustrates the capillary pressure drop. As described above, the capillary pressure drop is used to show the force that can be applied to pull a plate containing capillary fluid (such as water) apart. The curve described in the figure is derived from the calculation results related to two plates, that is, the contact surface and water. One plate is a silicon wafer and the other plate is a fused silica optical plate. The validity of this curve is based on the calculations and measurements related to the tested glass plate replacing the silicon dioxide. Compared to the glass and water curve, the existing curve shows that sufficient traction power can be generated within a nominal gap height of 10 microns and below 10 microns, even at a surface height of 5 microns that is quite suitable for normal lithography applications. A particularly meaningful range exists in the gap height below about 1 micron and below 1 micron. Since the gap height at this gap height, the pressure drop is more than 1 bar, indicating that the negative pressure in the gap liquid is already under atmospheric pressure produce. However, the close to 0.2 bar pressure drop at a gap height of 10 microns is sufficient to ensure that it can be used to safely process a wafer table and place the wafer (eg, embedded in a vacuum) for clamping.

Figure 3 illustrates a practical application of the invented operating principle and schematically shows a part of a lithography system, which includes a target in the form of a wafer 1, a wafer table 8 or the top side of a suction cup part Side 2, a liquid 3 in the form of water, and an O-ring 9 called viton or rubber. By being embedded in an edge portion of the wafer stage 8 with a reduced height, the O-ring 9 is used to seal the liquid vapor volatilized from the liquid 3 contained in the gap. Through this method, the top side of the O-ring is set to a height corresponding to the protrusion part 7, and therefore is set to be slightly higher than the protrusion part on the top side of the wafer table 8. 7 is more appropriate. A notch is provided on a radial side (in this application example, it is a radially inward turning side), the O-ring can be compressed between the wafer table and the wafer without providing excessive force However, the O-ring is sufficient to prevent vapor leakage, which is an important item in a vacuum environment where this type of lithography mechanism can be applied. In fact, the thickness of the O-ring here is in the range from 0 mm to 5 mm in diameter, so a C-ring is formed, indicating that the pressure required to compress the O-ring is kept to a minimum. Between the O-ring and the center of the target conveying mechanism 8 and the middle of the protruding table surface is to maintain some radial distance to allow for the opening (not shown here) Come), for example, for applying the fluid 3 to the return opening between the two. An O-ring or similar elastically deformable mechanism is suitable to be applied around the target. In this way, a larger force can be applied between the target and the elastically deformable mechanism, allowing the use of an elastically deformable mechanism with higher roughness, which has a higher roughness. Easy to use and relatively economical to purchase prices.

On the other hand, as in Fig. 4, the leakage of vapor is prevented by a vapor confinement ring 9A, which is supported by an outer edge of the wafer table to seal the liquid gap in a wide range. The surrounding opening of the wafer table leaves only a very small vertical distance 9B between the vapor confinement ring 9A and the target 1, where the target 1 is supported by the bump part 7 of the wafer table. The extremely small vertical distance 9B is in particular between one tenth to one 20th of the height of the gap between the target and the target table.

Furthermore, according to the configuration of the present invention, it is used according to the following operating principle. The liquid at a pressure lower than its vapor pressure is in a metastable state or can be in a metastable state. It is worth noting that a critical radius for cavitation is exceeded, allowing the cavitation to grow unrestricted. As in the preferred embodiment of the present invention, when the minimum size of the liquid-containing volume is made very small, or even smaller than the critical radius, the air pockets will no longer grow. When the pressure drop is from Laplace pressure, the critical radius is approximately twice or more of the gap height. The height is based on the material properties (contact angle) between the liquid and solid surface.

The present invention may further include the existence of one or more openings, which can be closed for fluid entry, wherein the fluid can be a gas, and the opening is opened to release the fluid in the wafer table, so , Used to release a target from the wafer stage. It is more appropriate that a pipe system for measuring the volume of fluid entering with high accuracy is provided in the center. The present invention may also include a pressing mechanism for initially pressing the target material into close contact with the target table, that is, close contact with the protrusions 7 on the target table. An example of using such a pressing mechanism relates to a high pressure directed toward the top side of the target material 1 along the vertical direction, thus reducing any bending of the target material and allowing the capillary action to be Install. A helpful way to achieve such pressure according to another aspect of the present invention is to direct the airflow of a fluid mechanism (such as wind and water) to the target.

Figure 5 illustrates a preferred mode of operation, in which the initial clamping action is additionally It is marked as chucking, that is, the bending phenomenon is removed during the movement in the target, and the liquid is guided between the target and the target table in a way of mixing. . So far, a central entry groove 10 is provided in the target table, and has a valve V. The wafer is subjected to a vacuum pressure P_vacThe generated vacuum force is chucked to the wafer stage, and the vacuum pressure P_vacIt is applied through a number of openings 10B appearing in the surroundings. When the wafer is definitely chucked to the wafer table, the valve V is opened and liquid will be sucked into the gap between the wafer and the wafer table. The filling speed of the water flowing into the gap is determined by the capillary pressure P_capAnd between the general vacuum pressure P_vacWith an excess pressure P_opDetermined by the sum of the pressure difference in the middle, and should exceed the pressure P_opIt is present or applied to the entrance of the groove 10, that is, a source of fluid that is not shown in a figure. Over pressure P_opIs defined as higher than the pressure P generally above the target_env. For practical reasons, the excess pressure P_opIs limited to 1 bar to make the excess pressure P_opWill not interfere with the positioning of the target on the wafer table, and the effective liquid pressure P_liqAre included in the calculation together.

Figure 6 illustrates a way to prevent, at least to further minimize the amount of liquid evaporation from the capillary gap, that is, from between the target and the target table. Around the target, in the target table, and in the area sealed by the elastically deformable mechanism 9 or the smallest gap 9B, a side groove with a relatively large width compared to the height of the capillary gap is made. To contain the liquid 3'that does not contain capillary action. The capillary-free liquid 3'is of the same type as the capillary-containing liquid 3, which is more suitable. However, it is provided on a relatively large surface or interface area. Although the side trench can use the pressure P for the trench 10_opThe liquid is filled by a source of liquid, and the liquid is filled through an independent water channel and valve. An independent filling mechanism is provided as more appropriate, that is, it is independent of capillary action to guide the supply of fluid. The filling mechanism may be any separate filling mechanism, for example, including a separate liquid source, a dedicated water channel and valve facing the side ditch, and/or a fluid pump.

Figure 7 illustrates an alternative way of guiding the capillary action layer. As in the first application example, in addition to flowing into the fluid through a central opening, the fluid here reaches either the wafer stage or the target by depositing droplets 11 (for example, by spraying). Surface or two surfaces. However, the deposition is more appropriate to adopt a controlled method to obtain a uniformly distributed liquid portion, for example, by using a droplet dispensing mechanism to spread the droplets, for example, the droplet dispensing mechanism It has one or more dispensing openings located at preset positions. Above In the deposition method, a rapid liquid distribution can be obtained, thus enhancing the feasibility of the existing novel clamping method and its mechanism. In the existing application example, the droplets are deposited on the target table 8. In this embodiment, the different openings 12 used to prevent air from being mixed in are distributed on the target table area in a preset manner, and it is usually more suitable to be uniformly distributed.

In addition to the above opening, the surface of the target table is defined by the existing protrusion parts 7 which are used to resist the clamping force of the capillary action liquid that increases the distribution density. In this way, an adsorbed target can be kept flat, that is, under the force of the capillary action fluid, there is no bending between the protrusion parts.

As a specific method, one or two contact surfaces of the target and the target table can be surface-treated, or coated with a layer of material, in particular to approach a required clamping pressure, more particularly in Under operating conditions, that is, in a vacuum, it affects a contact angle between the liquid and the relevant contact surface. In fact, in the application examples of wafers, an existing standard for targets is known, and only the target stage will be coated. In order to still influence the capillary pressure drop in the clamping force according to the present invention, taking into account the liquid material, the target material and the contact surface material of the target table, a specific and required pressure drop can be conceived. Adjust the height of the protrusion site. This adjustment can be used to meet the required minimum clamping force and to adapt to the distribution of the clamping force and the protrusion part or the mutual distance of a specific combination of results, especially to prevent this The local bending of the target material between the protrusion parts is known as a clamping pressure and the force generated on the target material. Therefore, a minimum height of the protrusions is taken into consideration, but the density of the protrusions can also be adjusted by considering, for example, increasing the density of the protrusions to meet a minimum required clamping force. The minimum height of the protrusions is considered based on a method to accommodate dust or other pollutants between the protrusions and within the gap height. The gap height is of course within the constraints of the method according to the present invention, wherein the gap height will be kept to a minimum, so that the fluid between the protrusions will not boil.

FIG. 8 illustrates the relevant part of the processing flow for a lithography tool or system improved by the present invention, in which the target material is composed of a wafer. The above part of the process starts from the action and status of the clean wafer stage CT marked in the lower left corner of the figure. Since then, there are two different processing paths that can be followed. The first and the above-explained part of the path is characterized by The first step WOT where the wafer is placed on the target table, the second step LIG is the second step LIG where the liquid between the target table and the wafer is flowed through a conduit in the target table, and the conduit for water is sealed The third step CS of staying (that is, removing liquid supply and air inclusions). The second possible way for carrying out the processing procedure according to the present invention is represented by the lower process branch, which shows the first step LOT of applying liquid on the target table, placing a wafer on the The second step WOT on the target table and the third step CS for sealing the duct. In this application example, the third step CS only includes sealing the air inclusions discharge port. The sealing effect is preferably performed on a central discharge port or on a supply pipe connected to the surface of the target table through a plurality of branch portions.

In a subsequent step IT, the target table and wafer are embedded in a part of the lithography system that is about to be placed in a vacuum. The wafer is processed in step PW. The target table and wafer Removed from the lithography tool in step RT, the wafer is detached from the target stage in step DW, and by removing or opening any catheter seals, the wafer is separated from other parts Come out, and the wafer table is cleaned.

In the application example of the liquid application step LIG, water is applied by at least one water pipe, or in addition, water can be supplied through the water pipe and flow into the gap by a plurality of water pipes. According to other aspects of the present invention, the filling effect of the gap is implemented by relying on a considerable capillary pressure to allow water or any other related liquid to be drawn into the gap. In another embodiment, the processing procedure is improved, that is, the pressure during filling is increased by using external pressure to accelerate the processing procedure. In another mode of operation of the present invention, the air mixing opening is also used to supply a lower pressure.

In the application example of the step LOT of applying water to the target table, the application of water is accomplished by applying uniformly distributed droplets on the surface of the wafer table or wafer. When the wafer is placed on the wafer table, the droplets will be distributed due to capillary action. This processing procedure can be aided by the adsorption through the opening holes. In the application example of the step CS of sealing the conduit, all the holes used to fill the gap must be sealed after the liquid is applied to prevent evaporation when the wafer table and the wafer are combined in a vacuum situation. In the application example of the processing step DW of separating a wafer from the target table, the openings for supplying water and/or preventing air inclusions can also be used to provide air pressure, and in the present invention Other In one mode of operation, the wafer is blown away from the target stage. In this application example, the air pressure is applied at least fairly evenly, so that the wafer will not be braked.

In addition, a smaller gap can also be considered, and the greater the pressure drop required to maintain the same flow velocity. The greater the amount of increase in pressure drop required, so the capillary pressure available from the smaller gap increases. Therefore, for smaller gaps, the flow conditions caused by capillary pressure are lower. In fact, gaps exceeding a critical gap height have several conditions, including liquid materials and contact surface materials. As it can be learned from the "capillary filling rate of water in nanogrooves", in a very small gap, an electroviscous effect increases the surface viscosity of water.

In order to reduce the influence of contamination due to particles on the rear side of the wafer, the protrusion part is necessary. The maximum pitch of the protrusions is determined by the deflection of the wafer between the protrusions caused by capillary pressure. The general value for the pitch of the protrusion part is 3 [mm]. Given other system conditions, such as material and size, the height of the protrusion determines the size of the gap, and is used to adjust the clamping pressure according to the present invention, and vice versa. The surface of each protrusion is made so as not to deform or brake under capillary pressure. The diameter of each protrusion part is about 25 microns or more. The shape of the protruding particles is usually round (that is, without edges), which is used to reduce the possibility of particle contamination during the cleaning process. The above particles come from the fabric wiping the target table.

In addition to or instead of using the protrusion part 7, as shown in FIG. 9, the spacer 15 (glass particles, silica particles, etc.) is uniformly dispersed on the conveying mechanism 8, for example, By spraying the dispersion solution of the gap member 15 onto the conveying mechanism 8 or by applying the dispersion solution of the gap member 15, therefore, the spacer 15 is provided. In one embodiment, the spacers 15 are dispersed in the liquid 3 whose final shape is the stationary phase liquid layer.

In addition to the concepts and all related details described in the previous documents, the present invention is about all the features defined in the content of the subsequent patent application, and those who are familiar with the accompanying graphics can directly and clearly derive Learn all the details. In the content of the subsequent patent application, in addition to fixing the meaning of a previous term, any reference component symbols corresponding to the structure in the graphics are used to assist in reading the application. The scope of the patent is requested to include the meaning of one as an application example, which is used solely to express a previous term, and therefore includes the content between the parentheses.

The following aspects of the invention are intended to be described herein, and this paragraph ensures that they are discussed. They are called aspects, and although they appear similar to the scope of the patent application, they are not the scope of the patent application. However, at a certain point in the future, these applicants reserve the right to claim any and all of these aspects in this application and any related applications.

1. A lithography system, for example, for projecting an image or an image pattern onto a target (1), the target is, for example, a wafer, and the target is covered by a target table (2) Included in the lithography system, there is a clamping mechanism for clamping the target on the target table, wherein the clamping mechanism includes a layer of stationary phase liquid (3), and the fixing liquid is contained in the target The thickness between the target table and the target table is used to provide the material of the liquid (C), and the material to provide the different contact surfaces (A, B) of the target (1) and the target table (2), a pressure drop (Pcap) will be generated.

2. The system of aspect 1, wherein the pressure drop produces a pressure (Pliq) within the liquid volume, the liquid pressure being lower than its vapor pressure.

3. The system as in aspect 1, wherein the pressure drop is realized in a vacuum.

4. As in the system of aspect 1, one of the pressures (Pliq) will be generated, which is significantly lower than a true environmental pressure (Penv) for the liquid layer (3).

5. The system as in aspect 1, wherein the mixing effect is configured to cause the lower pressure (Pliq) to generate a negative pressure under vacuum conditions, especially those generated in general lithography processing.

6. The system of aspect 1, wherein the wafer stage is provided with spacers (7, 15) for defining the thickness of the stationary phase liquid layer (3).

7. The system as in aspect 1, wherein the wafer table is provided with protrusions, and the liquid (3) is maintained under a capillary action condition (Pcap ), that is, the gap height is between the target table and the target, and is maintained at the minimum pressure required to provide the clamping condition. The liquid (3) avoids the possibility of boiling, that is, the formation of air pockets Possibility.

8. The system as in aspect 1, wherein the capillary action condition is achieved by keeping the distance between the surfaces between the target (1) and the target stage (8) between 0.1 micrometer and 10 micrometers Be realized.

9. The system as in aspect 1, in which a surrounding sealing mechanism such as an O-ring is included, especially for preventing liquid evaporation.

10. The system as in aspect 9, wherein the sealing mechanism is composed of an elastically deformable mechanism, viewed in cross section, especially having a generally C-shaped pattern.

11. The system of aspect 9, wherein an O-ring or similar elastically deformable mechanism is included around the target.

12. The system of aspect 9, wherein the sealing mechanism is composed of an O-ring, and the O-ring is provided with a slot-like slit extending along the circumference, facing a radial side of the O-ring Open, especially open toward the radial inner side, and extend to a substantial part beyond the diameter of the O-ring, especially upward to the center of the O-ring.

13. The system of aspect 9, wherein the surrounding sealing mechanism is formed as a surrounding air gap (9B) between the target table (8) and a height of the target, and the height is equal to or Less than the height required to maintain the capillary conditions.

14. The system of aspect 1, wherein the wafer table is provided with a side groove for accommodating fluid, the width of the side groove is significantly greater than the height of the gap, and is arranged on the target along the periphery A target conveying part of the material table is used for sealing the capillary action liquid between the target material and the target material table in the periphery defined by the sealing mechanism.

15. The system as in aspect 1, wherein the target stage is provided with a closable discharge opening, especially for releasing air, at least the gaseous material at the capillary liquid inlet, especially for the central part closure.

16. The system according to aspect 15, wherein the opening is included in a peripheral edge of a recess of the target table, so it is more appropriate to follow a wafer transport portion of the wafer table, that is, Contains suction cups, especially within the circumference defined by the sealing mechanism.

17. The system of aspect 15, wherein the discharge openings are included to be generally evenly distributed on the surface of the wafer table.

18. The system of aspect 1, wherein the clamping liquid is composed of water.

19. The system of aspect 1, wherein the target table is provided with at least one inlet opening which is preferably closable at the central part, especially for the inflow of capillary action liquid.

20. The system of aspect 1, wherein the inflow of fluid is achieved by spraying liquid onto any contact surface of the target table and the target.

21. The system of aspect 1, wherein the liquid is deposited in a controlled manner by the action of a liquid deposition mechanism that releases liquid droplets or liquid lines of controlled volume to the target material On the surface of the table.

22. The system of aspect 1, wherein the liquid is deposited by the action of a precision deposition mechanism including a plurality of deposition ports.

23. The system of aspect 7, wherein the density of the protrusions on the contact surface of the target table is determined by a nominal pitch value in the range of 1 mm to 3 mm.

24. The system according to aspect 1, wherein at least any contact surface of the target and the target table is provided with a coating layer whose material is different from the surface substrate.

25. The system as in aspect 1, wherein the initial pressure mechanism is provided to achieve an initial close contact between the target and the target table.

26. The system of aspect 25, wherein the initial pressure mechanism is realized by one or more supply openings in the central part of a valve including a supply groove, the supply groove being Connected to the opening, the valve is in a groove located in the center of all the above openings, or in each individual groove, before the fluid is supplied to the gap between the target and the target table , The valve will be closed, and the gap is exposed to vacuum pressure through other openings along the periphery of a wafer transport portion of the wafer table.

27. The system according to aspect 25, wherein the starting pressure mechanism includes a pump, such as a water pump and an air pump or a blower, especially used to force a flowing material, especially one of air and water The airflow reaches the target to obtain a first contact effect.

28. The system as in aspect 1, wherein the target stage is adapted to be used for unfettered contents, that is, a lithography tool for processing a target carried by the target stage, without connection catheter.

29. A wafer table for embedding in a vacuum environment such as a lithography tool, the wafer table having a clamping mechanism adapted to use a stationary phase liquid layer, especially according to aspect 1, Used to clamp a target, such as a wafer.

30. Such as the wafer table of aspect 29, where the mechanism is adapted to be used especially in The wafer stage is embedded in the vacuum compartment of a lithography tool to realize a clamping function outside the vacuum space of a lithography tool before processing a target material transported by the target stage.

31. A method for clamping an object having a substantially flat contact surface to another object also having a substantially flat contact surface, wherein in order to achieve the purpose of clamping the objects to each other, a fixed phase The liquid layer is used to maintain the capillary action between the surfaces.

32. The method of aspect 31, wherein the objects are part of a vacuum operable lithography system.

33. The method of aspect 31, wherein the two objects are pressed against each other especially by an air flow to allow the capillary action inclusion to be installed as a clamping mechanism.

34. The method of aspect 31, wherein the wafer stage is taken out of the lithography system to replace a target on the wafer stage.

35. The method of aspect 31, wherein a wafer table in a lithography tool is exchanged with another wafer table to achieve the goal of replacing a target in the lithography tool.

36. The method of aspect 31, wherein the target stage is processed outside a lithography tool, and wherein the processing temperature of the target stage is adjusted.