CN114690573A

CN114690573A - Lithographic apparatus

Info

Publication number: CN114690573A
Application number: CN202011595132.5A
Authority: CN
Inventors: 仲凯; 杨辅强; 杨铁刚; 刘剑; 赵丹平
Original assignee: Shanghai Micro Electronics Equipment Co Ltd
Current assignee: Shanghai Micro Electronics Equipment Co Ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2022-07-01

Abstract

The invention provides a photoetching device which comprises a main substrate, a workpiece table, an installation bottom plate, a grating ruler and a grating ruler reading head, wherein the grating ruler and the grating ruler reading head are arranged between the main substrate and the workpiece table, the grating ruler is fixed on one end surface of the installation bottom plate and is connected with the main substrate through a viscous damping device with adjustable damping and a flexible mechanism, which are arranged on the other end surface of the installation bottom plate, the grating ruler reading head is fixed on the workpiece table, and the relative displacement of the main substrate and the workpiece table is reflected through the relative movement between the grating ruler and the grating ruler reading head so as to measure the position movement of the workpiece table. According to the invention, the damping of the viscous damping device is adjusted by adjusting the contact area of the viscous fluid in the viscous damping device with the cylinder body and the piston, so that the vibration control effect of the viscous damping device is improved, and the measurement and photoetching precision of photoetching equipment is improved.

Description

Lithographic apparatus

Technical Field

The invention relates to the field of lithography equipment, in particular to lithography equipment.

Background

A lithographic apparatus is a semiconductor apparatus that applies a desired pattern onto a substrate. Prior art lithographic apparatus include measurement systems for determining the position of the workpiece table with high accuracy. Due to the continuous demand for higher production throughput and measurement accuracy, there is a need to improve the measurement accuracy of measurement systems in lithographic apparatuses, in particular for measurement systems for measuring the position of a workpiece table in six degrees of freedom.

The prior art measuring system comprises a grating or grid, a main substrate, and mounting means for mounting the grating or grid on the main substrate in a number of mounting points, temperature changes and/or temperature differences of the main substrate may cause changes in the shape of the main substrate. Other factors may also cause the shape of the main substrate to change, resulting in a change in the position of the mounting points on the mounting device, which may cause the grating or grid to deform, reducing the measurement accuracy of the measurement system. How to deal with the influence of heat transfer from the outside, vibration from a main substrate, thermal deformation of the main substrate and air pressure fluctuation generated in the high-speed motion process of a workpiece table on the measurement stability of the grating ruler of the workpiece table is a problem to be solved urgently.

Fig. 3 is a schematic structural diagram of a viscous damping device in a lithographic apparatus, referring to fig. 3, the viscous damping device includes a cylinder 61, a piston 62, and a viscous fluid 60 filled in a gap between the cylinder 61 and the piston 62, wherein the cylinder 61 is connected to a mounting base plate in the lithographic apparatus, the piston 62 is connected to a main base plate in the lithographic apparatus, for example, the piston 62 is connected to a connecting member 622 through a guide 621, and is fixedly connected to the mounting base plate through the connecting member 622. According to the theory of viscosity of fluid based on Newton's law of internal friction, when the cylinder 61 and the piston 62 generate relative motion, damping and rigidity characteristics relative to the space between the cylinder 61 and the piston 62 can be generated, so that the thermal deformation of the main substrate structure can be decoupled, the 1 vibration of the main substrate can be isolated, the air pressure disturbance of the motion of the workpiece table can be reduced, the influence of the structural mode of the mounting base plate on the measurement precision of the grating ruler can be inhibited, and the measurement and the photoetching precision of the photoetching machine can be improved. However, the viscous damping device has the following technical problems: (1) because of different movement speeds and accelerations of the workpiece table, the generated air pressure fluctuation is different, the impact disturbance on the grating ruler is different, and the vibration of the grating ruler can generate different influences; (2) because the vibration on the main substrate can be different due to the environment, the external disturbance is different, and finally the vibration response on the main substrate is different, and different influences can be generated on the vibration of the grating ruler. The measurement precision of the grating ruler changes in the measurement process due to the two reasons, and the measurement precision of the grating ruler needs to be monitored.

Disclosure of Invention

The invention aims to provide a photoetching device, which realizes the adjustable damping of a viscous damping device so as to improve the vibration control effect and improve the measurement and photoetching precision of the photoetching device.

The invention aims to provide a photoetching device which comprises a main substrate, a workpiece table, an installation base plate, a grating ruler and a grating ruler reading head, wherein the grating ruler and the grating ruler reading head are arranged between the main substrate and the workpiece table, the grating ruler is fixed on one end face of the installation base plate and is connected with the main substrate through a viscous damping device and a flexible mechanism, the viscous damping device and the flexible mechanism are arranged on the other end face of the installation base plate, the damping of the viscous damping device is adjustable, the grating ruler reading head is fixed on the workpiece table, and the relative displacement of the main substrate and the workpiece table is reflected through the relative movement between the grating ruler and the grating ruler reading head, so that the position movement of the workpiece table is measured.

Optionally, the viscous damping device includes a cylinder, a piston, and a viscous fluid filled in a gap between the cylinder and the piston, the piston includes a piston body and a protrusion disposed on a side wall of the piston body, a groove disposed on an inner wall of the cylinder and engaged with the protrusion, and at least a portion of the groove surrounds at least a portion of the protrusion.

Optionally, the piston main body is in the shape of an inverted circular truncated cone, the inner wall of the cylinder body is matched with the piston main body and is arranged in an inclined mode, and the inclination angle of the inner wall ranges from 30 degrees to 60 degrees.

Optionally, the protrusion is perpendicular to the piston body and is arranged in a vertical bar shape from top to bottom.

Optionally, the protrusion is perpendicular to the piston body and is disposed spirally around the piston body.

Optionally, the width of the protrusion gradually decreases from top to bottom, and/or the height of the protrusion gradually decreases from top to bottom.

Optionally, the width of the groove and the width of the protrusion are changed in the same proportion, and the depth of the groove and the height of the protrusion are changed in the same proportion.

Optionally, the size of the gap is 0.1mm to 1 mm.

Optionally, the viscous fluid has a viscosity of 0.65mm²/s～100000mm²/s。

Optionally, the cylinder of the viscous damping device is connected to the mounting base plate, and the piston of the viscous damping device is connected to the main base plate.

Optionally, the grating ruler is fixedly connected with the mounting base plate in an adhesion manner.

Optionally, the shape and size of the cross section of the mounting base plate in the direction parallel to one end face of the mounting base plate are the same as the shape and size of the grating ruler in the direction parallel to one end face of the mounting base plate, and a through groove is arranged in the middle of the mounting base plate.

Optionally, the material of the mounting base plate includes microcrystalline glass.

In summary, in the viscous damping device in the lithography apparatus provided by the invention, the side wall of the piston main body and the inner wall of the cylinder body are respectively provided with the mutually matched protrusion and groove, so that the contact area between the viscous fluid and the cylinder body and the piston is increased, the damping is further increased, the damping vibration attenuation effect is improved, and the application occasions of the viscous damping device are enlarged.

Furthermore, according to the distribution positions of the bulges, the height and the width of the bulges are arranged, so that the gap between the cylinder body and the piston can be adjusted under the condition that the mechanical structure sizes of the cylinder body and the piston are not changed, the damping adjustment is further realized, and the vibration control effect of the viscous damping device is improved.

Furthermore, the viscous damping device can decouple the thermal deformation of the main substrate structure, isolate the vibration of the main substrate, reduce the air pressure disturbance of the movement of the workpiece table, inhibit the influence of the structural mode of the installation bottom plate on the measurement precision of the grating scale and the like, and improve the measurement and the lithography precision of the lithography equipment.

Drawings

FIG. 1 is a schematic view of a lithographic apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of an embodiment of a viscous damping device in a lithographic apparatus;

FIG. 3 is a schematic view of a viscous damping device;

fig. 4 is a schematic structural diagram of a viscous damping device according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a hysteretic damper according to a second embodiment of the present invention;

fig. 6 is a schematic structural diagram of a viscous damping device according to a third embodiment of the present invention;

wherein the reference numerals are:

1-a main substrate; 2-a flexible mechanism; 3-grating ruler; 4-grating ruler reading head; 5-a workpiece table; 6-viscous damping means; 7-mounting a bottom plate;

61. 63, 611, 612-cylinder; 62. 64, 610, 613-piston; 60-viscous fluid; 621. 641-a guide bar; 622. 642-connecting member.

Detailed Description

The lithographic apparatus of the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description and drawings, it being understood, however, that the concepts of the present invention may be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. The drawings are in a very simplified form and are not to scale, merely for convenience and clarity in describing embodiments of the invention.

The terms "first," "second," and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other sequences than described or illustrated herein. Although elements in one drawing may be readily identified as such in other drawings, the description herein does not refer to all of the same elements as illustrated in each drawing for clarity of description.

Example one

Fig. 1 is a schematic partial structural diagram of a lithographic apparatus provided in this embodiment, as shown in fig. 1, the lithographic apparatus includes a main substrate 1, a workpiece stage 5, a mounting base plate 7, a grating scale 3, and a grating scale reading head, the workpiece stage 5 is located below the main substrate 1, the grating scale 3 and the grating scale reading head 4 are both located between the main substrate 1 and the workpiece stage 5, the grating scale 3 is fixed on one end surface of the mounting base plate 7, the grating scale 3 and the main substrate 1 are connected to each other through a viscous damping device 6 and a flexible mechanism 2 that are arranged on the other end surface of the mounting base plate 7, the grating scale reading head 4 is fixed on the workpiece stage 5, and a relative displacement between the main substrate 1 and the workpiece stage 5 is reflected by a relative movement between the grating scale 3 and the grating scale reading head 4, and then the position movement value of the work stage 5 is measured.

One end of the viscous damper 6 and one end of the flexible structure 2 are connected with the mounting base plate 7, the other end of the viscous damper is fixedly connected with the main base plate 1 through screws, and the grating ruler 3 is fixedly connected with the mounting base plate 7 in a bonding mode. The viscous damper 6 and the flexible structure 2 are fixedly connected to the end face of the mounting baseplate 7 close to the main substrate 1 in a screw connection manner. It should be appreciated that such limitation is only used for illustrating the connection manner of the grating scale 3, the flexible mechanism 2 and the viscous damping device 6 with the mounting substrate 7, respectively, the grating scale 3 may also be connected in a plug-in manner, and the flexible mechanism 2 and the viscous damping device 6 may also be connected in an adhesive manner or the like.

Further, a through groove (not labeled in the figure) is provided on the mounting base plate 7 to provide a light path channel of a projection exposure optical system of the lithography machine. The open position of the through groove is matched with the grating ruler 3, for example, the through groove is positioned at the geometric center of the mounting base plate 7. The cross section of the through groove in the direction parallel to one end face of the mounting base plate 7 is circular or square. The through groove can also be in a shape of triangle, rhombus or parallelogram and the like in the cross section under the condition of ensuring the provision of the optical path channel of the projection exposure optical system of the photoetching machine. The shape and size of the cross section of the mounting base plate 7 in the direction parallel to one end face thereof are the same as those of the cross section of the grating scale 3 in the direction parallel to one end face of the mounting base plate 7. It should be appreciated that such a limitation is merely used to illustrate the relationship between the shape and size of the cross section of the mounting base plate 7 in the direction parallel to one end face thereof and the cross section of the grating ruler 3 in the direction parallel to one end face of the mounting base plate 7, and the shapes and sizes thereof may be different.

Fig. 2 is a schematic cross-sectional view of an installation position of the viscous damping device provided in this embodiment, and the layout of the viscous damping device 6 is performed according to comprehensive consideration such as a modal shape and a spatial position of the installation base plate 7, but not limited to the layout scheme in this embodiment, and the arrangement position and the number of the viscous damping device vibration devices may be adjusted as required. As shown in fig. 2, the number of the compliant mechanisms 2 and the viscous damping devices 6 is multiple, the plurality of compliant mechanisms 2 and the viscous damping devices 6 are evenly distributed around the through grooves, and the compliant mechanisms 2 and the viscous damping devices 6 are alternately distributed exemplarily.

Further, the material of the mounting base plate 7 includes microcrystalline glass, which has a small coefficient of thermal expansion and good thermal stability, and can reduce the influence of vibration from the main substrate 1, and further improve the measurement accuracy of the grating ruler 3. It should be appreciated that such limitation is only used for illustrating the material of the mounting plate 7, the material of the mounting plate 7 may also be a material similar to the mechanical property of the glass ceramics, such as K9 glass, and the material of the mounting plate 10 should have the characteristics of small thermal expansion coefficient and good thermal stability.

Fig. 4 is a schematic structural diagram of a viscous damping device in a lithographic apparatus according to this embodiment, referring to fig. 4, the viscous damping device includes a cylinder 63, a piston 64, and a viscous fluid 60 filled in a gap between the cylinder 63 and the piston 64, the piston 61 is in the shape of a rounded frustum, an inner wall of the cylinder 63 is disposed in an inclined manner in cooperation with the piston 64, and an inclination angle θ of the inner wall of the cylinder is in a range of 30 ° to 60 °.

The magnitude of the damping and stiffness characteristics produced by the viscous damping device is mainly determined by the clearance between the cylinder 63 and the piston 64, the height and diameter (or contact area) of the piston 64, and the viscosity of the viscous fluid between the cylinder 63 and the piston 64. The clearance between the cylinder 63 and the piston 64 is increased, the viscous damping force is reduced, and the rigidity is reduced; the height and diameter of the piston 64 are increased, the viscous damping force is increased, and the rigidity is increased; the viscosity coefficient of the viscous fluid between the cylinder 63 and the piston 64 increases, the viscous damping force increases, and the rigidity increases. In this embodiment, the size of the gap between the cylinder 63 and the piston 64 is 0.1mm to 1mm, and the viscosity of the viscous fluid 60 filled in the gap between the cylinder 63 and the piston 64 is 0.65mm²/s～100000mm²And/s, the viscous fluid 60 can be silicon oil with a higher viscosity coefficient, and can be filled with other fluids according to requirements. According to the parameters, the viscous damping device provided by the embodiment can provide a damping coefficient of 1000 s/m-50000 Ns/m.

Referring to fig. 1 and 4, the cylinder 63 is connected to the mounting plate 7, and the piston 64 is connected to the main substrate 1, for example, the piston 64 is connected to a connecting member 642 through a guide rod 641, and is fixedly connected to the mounting plate 7 through the connecting member 642. According to the viscosity theory of Newton's internal friction law on fluid, when the cylinder 63 and the piston 64 generate relative motion, damping and rigidity characteristics relative to the space between the cylinder 63 and the piston 64 can be generated, so that the thermal deformation of the main substrate structure can be decoupled, the vibration of the main substrate 1 can be isolated, the air pressure disturbance of the motion of the workpiece table 5 can be reduced, the influence of the structural mode of the mounting substrate 7 on the measurement precision of the grating ruler 3 can be inhibited, and the measurement and photoetching precision of the photoetching machine can be improved. The damping can be adjusted by adjusting the relative motion of the cylinder 63 and the piston 64, so that the vibration of the grating ruler is inhibited, and the measurement and lithography precision of the lithography machine is improved.

Example two

Fig. 5 is a schematic structural diagram of a viscous damping device in a lithographic apparatus according to this embodiment, and as shown in fig. 5, the viscous damping device according to this embodiment includes a cylinder 611, a piston 610, and a viscous fluid 60 filled in a gap between the cylinder 611 and the piston 610, where the piston 610 includes a piston body and a protrusion disposed on a sidewall of the piston body, a groove disposed on the sidewall of the cylinder 611 and matching with the protrusion, and at least a portion of the groove surrounds at least a portion of the protrusion.

In this embodiment, as shown in fig. 5, the protrusion is perpendicular to the piston main body and spirally disposed around the piston main body. Correspondingly, the depth of the groove is matched with the height of the protrusion, the width of the groove is matched with the width of the protrusion, at least one part of the groove surrounds at least one part of the protrusion, and a gap is formed between the protrusion and the groove, so that the protrusion and the groove can move relatively. A viscous fluid 60 is filled between the cylinder 611 and the piston 610, the viscous fluid 60 fills the gap between the protrusion and the groove, and both the cylinder 611 and the piston 610 generate relative movement, i.e., the protrusion and the groove move relative to each other, to provide a damping characteristic effect. Compared with the first embodiment, in the present embodiment, due to the arrangement of the protrusions and the grooves, the contact area between the viscous fluid 60 and the cylinder 611 and the piston 610 is increased, and the damping is increased, which can be applied to more occasions.

It should be noted that the protrusion is spirally arranged around the piston main body, and the width of the protrusion may be consistent from top to bottom, or the height of the protrusion may gradually decrease from top to bottom, and/or the width of the protrusion may gradually decrease from top to bottom. Accordingly, the depth and width of the recess of the groove are varied in equal proportion to the height and width of the projection.

In this embodiment, the protrusion spirally surrounds the piston body, and the height and width of the protrusion change with the height of the protrusion, when the piston 610 rotates a certain angle relative to the cylinder 611, the gap (depth gap) between the protrusion and the groove in the horizontal direction and the gap (width gap) between the protrusion and the groove in the vertical direction both change, that is, the overall gap between the piston 610 and the cylinder 611 changes, the contact area between the viscous fluid 60 and the cylinder 611 and the piston 610 changes, and the damping changes. Therefore, by setting the height and width of the protrusion, the gap between the cylinder 611 and the piston 610 can be adjusted without changing the mechanical structure size of the cylinder and the piston, so as to achieve damping adjustment and improve the vibration control effect of the viscous damping device.

EXAMPLE III

Fig. 6 is a schematic structural diagram of a viscous damping device in a lithographic apparatus according to this embodiment, where an upper half portion of fig. 6 is a partial top view of the viscous damping device, and a lower half portion is a partial planing view of the viscous damping device, as shown in fig. 6, the viscous damping device according to this embodiment includes a cylinder 612, a piston 613, and a viscous fluid 60 filled in a gap between the cylinder 612 and the piston 613, the piston 613 includes a piston main body and a protrusion disposed on a side wall of the main body, a groove configured to fit with the protrusion is disposed on one side of the cylinder 612, and at least a portion of the groove surrounds at least a portion of the protrusion.

The piston 613 is shaped as an inverted circular truncated cone, the inclination angle θ of the inner wall of the cylinder 612 is in the range of 30 ° to 60 °, and the protrusions are perpendicular to the piston main body and are arranged in a vertical bar shape from top to bottom. Optionally, the protrusions are uniformly distributed on the side wall of the piston body, the depth of the groove is matched with the height of the protrusions, the width of the groove is matched with the width of the protrusions, at least one part of the groove surrounds at least one part of the protrusions, namely, at least one part of the protrusions is embedded in the groove, and gaps are reserved between the protrusions and the grooves to ensure that the protrusions and the grooves can move relatively. The viscous fluid 60 is filled between the cylinder 612 and the piston 613, and a damping characteristic effect is provided when the two move relatively. In this embodiment, as compared with the first embodiment, the contact area of the viscous fluid 60 with the cylinder 65 and the piston 66 is increased and the damping is increased due to the provision of the projections and the grooves. Meanwhile, the relative positions of the cylinder 612 and the piston 613 are changed, so that damping adjustment is realized under the condition that the size of a mechanical structure is not changed, the adjustment precision of the viscous damping device is improved, and the viscous damping device is suitable for more occasions.

The shape, distribution position, size and number of the protrusions and the grooves in the present embodiment are not limited to the present embodiment, and can be adjusted by those skilled in the art as needed.

It should be noted that, in the present specification, all the embodiments are described in a related manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the structural embodiment, since it is substantially similar to the method embodiment, the description is relatively simple, and for the relevant points, reference may be made to the partial description of the method embodiment.

The above description is only for the purpose of describing the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention, and any variations and modifications made by those skilled in the art based on the above disclosure are within the scope of the appended claims.

Claims

1. A photoetching device is characterized by comprising a main substrate, a workpiece table, an installation base plate, a grating ruler and a grating ruler reading head, wherein the grating ruler and the grating ruler reading head are arranged between the main substrate and the workpiece table, the grating ruler is fixed on one end face of the installation base plate and is connected with the main substrate through a viscous damping device and a flexible mechanism, the viscous damping device and the flexible mechanism are arranged on the other end face of the installation base plate, the damping of the viscous damping device is adjustable, the grating ruler reading head is fixed on the workpiece table, and the relative displacement of the main substrate and the workpiece table is reflected through the relative movement between the grating ruler and the grating ruler reading head, so that the position movement of the workpiece table is measured.

2. The lithographic apparatus of claim 1, wherein the piston body is shaped as a rounded frustum, and the inner wall of the cylinder body is obliquely disposed to fit the piston body, the angle of inclination of the inner wall being 30 ° to 60 °.

3. The apparatus according to claim 1 or 2, wherein the viscous damping device comprises a cylinder, a piston, and a viscous fluid filled in a gap between the cylinder and the piston, the piston comprises a piston body and a protrusion provided on a side wall of the body, an inner wall of the cylinder is provided with a groove that fits the protrusion, and at least a part of the groove surrounds at least a part of the protrusion.

4. The lithographic apparatus of claim 3, wherein the protrusion is perpendicular to the piston body and is arranged in a vertical bar from top to bottom.

5. The lithographic apparatus of claim 3, wherein the protrusion is perpendicular to the piston body and is helically disposed around the piston body.

6. The lithographic apparatus of claim 5, wherein the width of the protrusion gradually decreases from top to bottom, and/or the height of the protrusion gradually decreases from top to bottom.

7. The lithographic apparatus of claim 6, wherein the width of the groove and the width of the protrusion vary proportionally, and the depth of the groove and the height of the protrusion vary proportionally.

8. The lithographic apparatus of claim 2, wherein the gap has a size of 0.1mm to 1 mm.

9. The lithographic apparatus of claim 2, wherein the viscous fluid isThe viscosity is 0.65mm²/s～100000mm²/s。

10. The lithographic apparatus of claim 1, wherein the cylinder of the viscous damping device is connected to the mounting base plate and the piston of the viscous damping device is connected to the primary base plate.

11. The lithographic apparatus of claim 1, wherein the grating scale is fixedly connected to the mounting base plate by bonding.

12. The lithographic apparatus according to claim 1, wherein the mounting base plate has a cross section parallel to one end surface thereof having the same shape and size as the grating scale, and a through-groove is provided in the middle of the mounting base plate.

13. The lithographic apparatus of claim 1, wherein the material of the mounting baseplate comprises microcrystalline glass.