WO2015101194A1

WO2015101194A1 - Objective lens support device and photoetching machine

Info

Publication number: WO2015101194A1
Application number: PCT/CN2014/094749
Authority: WO
Inventors: 王茜
Original assignee: 上海微电子装备有限公司
Priority date: 2013-12-31
Filing date: 2014-12-24
Publication date: 2015-07-09
Also published as: KR101860406B1; TWI541616B; KR20160100379A; CN104749904A; CN104749904B; TW201531814A

Abstract

Disclosed are an objective lens support device and a photoetching machine (100). The objective lens support device is installed on the photoetching machine (100). The objective lens support device comprises a main support device (101) and an auxiliary support device (102). One end of the main support device (101) is connected to an objective lens flange (104), and the other end thereof is installed on a main substrate (107). One end of the auxiliary support device (102) is connected to an objective lens body (103), and the other end thereof is installed on an internal frame. By respectively arranging a main support device and an auxiliary support device at an objective lens flange and an objective lens body, entirely rotating the mode vibration shape around the horizontal direction (direction X or direction Y) by taking an installation surface of the objective lens flange as a centre can be eliminated, thereby increasing the mode frequency value of each order of vibration shape, shortening the displacement response differences among the top, the centre and the bottom of the objective lens, and improving the exposure accuracy.

Description

Objective lens support device and lithography machine

Technical field

The present invention relates to a lithography machine, and more particularly to an objective lens support device and a lithography machine.

Background technique

In the working process of the lithography machine system, the workpiece table and the mask table are respectively based on the two axes and one axis (object surface, focal plane and optical axis) of the projection objective lens, and the workpiece table is realized according to the required precision under the driving of the control system. The relative position between the mask tables and the position of the two relative to the objective lens. Due to the high positioning accuracy and high synchronous motion accuracy of the lithography machine, any external vibration and internal vibration interference will cause a temporary misalignment between the two or the objective lens position, which will seriously affect the light. Engraved quality. The main factors causing micro-vibration inside the system and causing misalignment are the introduction of ground-based vibration, the reaction forces and moments generated during stepping or scanning, and the internal world (including: gas-liquid pipeline and gas film vibration) and the external world. Noise, etc. In order to eliminate the influence of various vibration factors on the exposure quality of the lithography machine, it is necessary to take effective vibration isolation and vibration reduction measures for the whole system. The usual solution is to try to isolate the exposure unit of the lithography machine (mainly including the illumination system, the mask table, the objective lens and the workpiece table) from the ground through a set of dampers, so that external vibrations can be prevented from passing through the foundation. Give the exposure unit.

With the increase of the integration degree of large-scale integrated circuit devices, the resolution of lithography work is getting higher and higher, that is, the stability of the exposure system of the lithography machine, the accuracy of the measurement system, and the accuracy of the motion platform are also getting higher and higher. At the same time, the working wavelength is getting shorter and shorter. After entering nanometer precision, the resolution of lithography is quite sensitive to the effects of vibration. As the most precise part and benchmark in the lithography machine, the projection objective lens is very demanding on environmental vibration. The single-stage vibration reduction achieved by the damper can no longer meet its performance requirements.

Usually, the objective lens is supported on the main substrate by a stainless steel block, and the objective lens is provided with a mounting flange. The flange is vertically disposed near the center of gravity of the objective lens, and one end of the stainless steel block is mounted on the flange surface, and the other end is connected to the main substrate. Realize the support of the objective lens. Due to layout space, mechanical structure or other reasons, The vertical mounting surface of the objective lens mounting flange cannot be completely equal to the center of gravity of the objective lens. The overall first- and second-order vibration modes of the objective lens (or the second six-order mode) are oriented horizontally around the flange mounting surface (X-direction). Or Y to) rotate.

Therefore, regardless of the flexible or rigid connection method, connecting the objective lens to the main substrate only at the flange mounting surface inevitably causes the first-order mode shape of the objective lens to rotate in a horizontal direction (X-direction or Y-direction). The displacement response between the top, center and bottom of the objective lens produces a dynamic difference, which jeopardizes the dynamic stability of the objective lens and affects the exposure accuracy.

Summary of the invention

The invention provides an objective lens supporting device and a lithography machine, which are used for eliminating a rotating mode vibration mode around a mounting surface of an objective lens flange as a whole.

In order to solve the above technical problems, the present invention provides an objective lens supporting device for a lithography machine, the lithography machine including an objective lens system and an inner frame, the inner frame including a main substrate, and the objective lens system is mounted on the main body On the substrate, the objective lens system includes an objective lens body and an objective lens flange, wherein the objective lens support device comprises: one or more vertically disposed main support devices and one or more horizontally disposed auxiliary support devices; wherein One end of each of the main supporting devices is connected to the objective lens flange, and the other end is mounted on the main substrate; one end of each of the auxiliary supporting devices is connected to the objective lens main body, and the other end is mounted on the inner frame.

Preferably, the primary support means is a rigid support or a flexible support.

Preferably, the objective lens supporting device comprises one set or three to six sets of the main support means.

Preferably, the 3 to 6 sets of main support devices are perpendicular to the mounting surface of the objective lens flange at the same height.

Preferably, the inner frame further comprises a measuring bracket and a mask table bracket, and the other end of each of the auxiliary supporting devices is mounted on the main substrate, the measuring bracket or the mask table bracket by a connecting member.

Preferably, the auxiliary support device is a rigid support or a flexible support.

Preferably, the auxiliary support device comprises a flexible hinge.

Preferably, the auxiliary support device is one set or three to six sets.

Preferably, the 3-6 sets of auxiliary support devices are vertically at the same height.

Preferably, the following formula is satisfied between the main supporting device and the auxiliary supporting device:

Wherein, K _{x1 is} the total stiffness of the X-direction of the main supporting device, K _x2 is the total stiffness of the X-direction of the auxiliary supporting device; K _{y1 is} the total stiffness of the Y-direction of the main supporting device, and K _y2 is the total stiffness of the Y-direction of the auxiliary supporting device; l ₁ is the vertical distance between the mounting surface of the objective lens flange and the center of gravity of the objective lens, and l ₂ is the vertical distance between the auxiliary supporting device and the center of gravity of the objective lens body.

Advantageously, said auxiliary support means is located directly above said main support means.

Preferably, the objective lens supporting device further includes a damper on one side of the main supporting device and the auxiliary supporting device, respectively.

The present invention also provides a lithography machine using the above objective lens supporting device.

Compared with the prior art, the present invention has the following advantages:

1. The main support device and the auxiliary support device are respectively disposed at the flange of the objective lens and the main body of the objective lens, thereby eliminating the rotation mode of the whole horizontal mode around the mounting surface of the objective lens flange, and improving the modal frequency of each mode shape. The value reduces the displacement response difference between the top, center and bottom of the objective lens to improve the exposure accuracy;

2. The auxiliary support device coexists with the main support device to avoid stress concentration of the flexible support structure caused by the weight of the objective lens, reduce structural stress, and improve fatigue life;

3. The structure is simple, suitable for various types of lithography machines, and it is convenient to modify the installation method of the objective lens of the existing model lithography machine.

DRAWINGS

1 is a schematic view showing the structure of an objective lens supporting device mounted on a split frame type lithography machine in Embodiment 1;

Figure 2 is a schematic view showing the vertical position of the main supporting device and the auxiliary supporting device in the first embodiment;

3 is a schematic view showing the vertical distance between the objective lens supporting device and the center of gravity of the objective lens body in Embodiment 1;

Figure 4 is a schematic view showing the horizontal position of the main support of the objective lens in Embodiment 1;

Figure 5 is a schematic view showing the horizontal position of the objective lens auxiliary support in the first embodiment;

Fig. 6 is a schematic view showing the structure of the objective lens supporting device mounted on the integral frame type lithography machine in the second embodiment.

1 to 5: 100-lithography machine, 101-main support device, 102-auxiliary support device, 103-object lens body, 104-object lens flange, 105-damper, 106-connector, 107-main substrate, 108-damper, 109-basis frame.

In Figure 6: 200-lithography machine, 201-main support device, 202-auxiliary support device, 203-object lens body, 204-object lens flange, 205-damper, 206-connector, 207-main substrate, 208- Shock absorber, 209-main substrate holder.

detailed description

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims. It should be noted that the drawings of the present invention are in a simplified form and both use non-precise proportions, and are merely for convenience and clarity to assist the purpose of the embodiments of the present invention.

Example 1

Taking the split frame lithography machine 100 shown in FIG. 1 as an example, the lithography machine 100 is placed on a foundation, including a main component such as an illumination system, a projection objective, a workpiece stage, a mask table, etc., since the present invention mainly relates to The supporting means of the objective lens, for the sake of simplicity, the components of the illumination system, the workpiece table, the mask table and the like are omitted in the drawings, however, this does not affect the understanding of the present invention by those skilled in the art. As shown in FIG. 1, the main substrate 107 is mounted on a base frame 109 by a damper 108 mounted on a main substrate 107, which includes an objective lens main body 103 and an objective lens flange 104. In the split frame lithography machine 100 of the present embodiment, the workpiece stage (not shown) and the main substrate 107 are supported by different dampers, In the present embodiment, the damper 108 is used to support the main substrate 107. 2 to 5, the objective lens supporting device of the present invention comprises one or more vertical (Z-direction) main support devices 101 and one or more horizontal support (in the XY plane) auxiliary support device 102. One end of each of the main supporting devices 101 is connected to the objective lens flange 104, and the other end is mounted on the main substrate 107; one end of each of the auxiliary supporting devices 102 is connected to the objective lens main body 103, and the other end is installed inside. The frame is specifically the other substrate 107, the measuring bracket, the mask table or other positions of the inner frame. In the embodiment, the other end of the auxiliary supporting device 102 is mounted on the main substrate 107 via the connecting member 106. The objective lens supporting device of the present invention mounts the main supporting device 101 and the auxiliary supporting device 102 at the objective lens flange 104 and the objective lens main body 103, respectively, and can eliminate the entire horizontal direction (X direction or Y) centering on the mounting surface of the objective lens flange 104. To the rotational mode shape, the modal frequency value of each mode is improved, and the displacement response difference between the top, center and bottom of the objective body 103 is reduced, and the exposure accuracy is improved.

1 to 5, the main support device 101 may be a rigid support or a flexible support. The main support device 101 is a group or a group of 3-6, and the 3-6 sets of the main support device 101 and the objective lens flange 104 are provided. The mounting faces are perpendicular to the same height. Similarly, the auxiliary support device 102 can also be a rigid support or a flexible support, which is realized by a single set or a combination of 3-6 sets, and 3-6 sets of auxiliary support devices 102 are vertically at the same height. Preferably, the number of sets of the auxiliary support devices 102 is the same as the number of sets of the main support device 101 and the set positions are corresponding.

Specifically, referring to FIG. 4 to FIG. 5, and in conjunction with FIG. 1, in the embodiment, the objective lens flange 104 and the main substrate 107 are connected by three sets of main supporting devices 101, and the three sets of main supporting devices 101 are evenly arranged. The objective lens main body 103 has an outer circumference and is disposed at an angle of 120° with respect to the central axis of the objective lens main body 103. The objective lens main body 103 and the main substrate 107 are connected by three sets of auxiliary supporting devices 102. The extension lines of the three sets of auxiliary supporting devices 102 are coincident with a point on the central axis of the objective lens main body 103, and the two are distributed at an angle of 120°. The support device 102 is located directly above the main support device 101. Further, the auxiliary support device 102 has a flexible hinge structure to ensure a large rigidity in the horizontal direction and a vertical stiffness as small as possible. In general, the vertical (Z-direction) total stiffness of the auxiliary support device 102 (i.e., the sum of the Z-direction stiffness of all of the auxiliary support devices 102) is less than the horizontal total stiffness, typically less than 10 ⁸ N/m, to avoid vibration of the internal frame. The objective lens main body 103 is delivered.

Referring to FIG. 3, the total X-direction stiffness of the main support device 101 (ie, the sum of the X-direction stiffness of all the main support devices 101) is _Kx1 , and the mounting surface of the objective lens flange 104, that is, the bottom of the objective lens flange 104. the plane of the center of gravity O of the objective lens body 103 is the vertical distance l _1, X auxiliary support device 102 to the total rigidity (i.e. all X auxiliary support device 102 and the rigidity of) of K _x2, with auxiliary support means 102 The objective lens body 103 has a center of gravity O with a vertical distance of l ₂ and satisfies the following conditions:

It is assumed that the total Y-direction stiffness of the main supporting device 101 (that is, the sum of the Y-direction stiffness of all the main supporting devices 101) is K _y1 , and the vertical distance between the mounting surface of the objective lens flange 104 and the center of gravity O of the objective lens main body 103 is l ₁ . The Y-direction total stiffness of the support device 102 (i.e., the sum of the Y-direction stiffness of all the auxiliary support devices 102) is K _y2 , and the auxiliary support device 102 and the objective lens body 103 have a center of gravity O vertical distance of l ₂ , which satisfies the following conditions:

Wherein, the horizontal stiffness of the auxiliary support device 102 depends on the horizontal stiffness of the main support device 101, and the lower the vertical stiffness of the auxiliary support device 102, the lower the vibration transmission of the inner frame to the objective lens main body 103 can be reduced.

Referring to FIG. 1, preferably, in order to avoid the resonance of the main support device 101 or the auxiliary support device 102 caused by the vibration frequency close to the natural frequencies of the main support device 101 and the auxiliary support device 102, the influence on the vibration isolation is described. One side of the main support device 101 and the auxiliary support device 102 are also provided with dampers 105, respectively.

The random response calculation results using the conventional objective lens supporting device and the projection objective lens using the objective lens supporting device of the present embodiment are as shown in Table 1:

Table 1 random response calculation results

Random response input/output setting: The measured acceleration spectrum of the main substrate 107 is loaded at the interface of the objective lens main body 103 and the main substrate 107, and the displacement response difference between the top surface of the objective lens main body 103 and the center of the objective lens main body 103 is output.

Example 2

As shown in FIG. 6, in the embodiment, the integral frame type lithography machine 200 is taken as an example, and the workpiece stage and the main substrate 207 are supported by the same damper 208. The same components in Fig. 6 as those in Fig. 1 are denoted by like reference numerals.

As in Embodiment 1, the objective lens supporting device includes: one or more vertically disposed main supporting devices 201 and one or more horizontally disposed auxiliary supporting devices 202, wherein one end of the main supporting device 201 and the objective lens method The blue 204 is connected, and the other end is mounted on the main substrate 207; one end of the auxiliary supporting device 202 is connected to the objective lens main body 203, and the other end is mounted on the inner frame through the connecting member 206, specifically the main substrate, the measuring bracket and the mask table. Or other location of the internal frame. Since the function of the objective lens supporting device in this embodiment is the same as that of the first embodiment, it will not be described herein.

In summary, the objective lens supporting device of the present invention is mounted on a lithography machine, comprising: a main supporting device and an auxiliary supporting device; wherein one end of the main supporting device is connected to the objective lens flange, and the main supporting device is another One end is mounted on the main substrate; one end of the auxiliary support device is coupled to the objective lens body, and the other end of the auxiliary support device is mounted on the inner frame. In the objective lens supporting device of the present invention, the main supporting device and the auxiliary supporting device are respectively disposed at the objective lens flange and the objective lens main body, thereby eliminating the entire horizontal (X-direction or Y-direction) rotating mode centering on the mounting surface of the objective lens flange. State mode, Improve the modal frequency value of each mode shape, reduce the displacement response difference between the top, center and bottom of the objective lens, and improve the exposure accuracy. It can also avoid the stress concentration of the flexible support structure caused by the weight of the objective lens, reduce the structural stress and improve the fatigue life. In addition, the invention has simple structure, is suitable for various types of lithography machines, and is convenient for modifying the installation mode of the objective lens of the existing model lithography machine.

It will be apparent to those skilled in the art that various modifications and variations can be made in the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims

An objective lens supporting device for a lithography machine, the lithography machine comprising an objective lens system and an inner frame, the inner frame comprising a main substrate, the objective lens system being mounted on a main substrate, the objective lens system comprising an objective lens a body and an objective lens flange, wherein the objective lens support device comprises: one or more vertically disposed main support devices and one or more horizontally disposed auxiliary support devices; wherein each of the main support devices One end is connected to the objective lens flange, and the other end is mounted on the main substrate; one end of each of the auxiliary supporting devices is connected to the objective lens main body, and the other end is mounted on the inner frame.
The objective lens supporting device according to claim 1, wherein said main supporting device is a rigid support or a flexible support.
The objective lens supporting device according to claim 1, wherein said objective lens supporting means comprises one set or three to six sets of said main supporting means.
The objective lens supporting device according to claim 3, wherein said 3 to 6 sets of main supporting means are vertically at the same height as the mounting surface of the objective lens flange.
The objective lens supporting device according to claim 1, wherein the inner frame further comprises a measuring bracket and a mask table bracket, and the other end of each of the auxiliary supporting devices is mounted on the main substrate, the measuring bracket or the connecting member via a connecting member. On the mask table bracket.
The objective lens supporting device according to claim 1, wherein the auxiliary supporting device is a rigid support or a flexible support.
The objective lens support device of claim 6 wherein said auxiliary support means comprises a flexible hinge.
The objective lens supporting device according to claim 1, wherein said auxiliary supporting means is one set or three to six sets.
The objective lens supporting device according to claim 8, wherein said 3 to 6 sets of auxiliary supporting means are vertically at the same height.
The objective lens supporting device according to claim 1, wherein the main supporting device and the auxiliary supporting device satisfy the following formula:

Wherein, K x1 is the total stiffness of the X-direction of the main supporting device, and K x2 is the total stiffness of the X-direction of the auxiliary supporting device;

K y1 is the Y-direction total stiffness of the main support device, and K y2 is the Y-direction total stiffness of the auxiliary support device;

l 1 is the vertical distance between the mounting surface of the objective lens flange and the center of gravity of the objective lens, and l 2 is the vertical distance between the auxiliary supporting device and the center of gravity of the objective lens body.
The objective lens supporting device according to claim 1, further comprising a damper on a side of said main supporting device and said auxiliary supporting device, respectively.
The objective lens supporting device according to claim 1, wherein said auxiliary supporting device is located directly above said main supporting device.
A lithography machine characterized by using the objective lens supporting device according to any one of claims 1-12.