JP2769897B2 - Exposure equipment - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an exposure apparatus used for manufacturing a semiconductor device or the like, and more particularly, to a stage mount for supporting a projection lens mounting base from the floor and mounting a substrate. The present invention relates to an exposure apparatus having a structure for suspending from a projection lens mount.

[Prior art] Conventionally, as an exposure apparatus used for manufacturing a semiconductor element,
An apparatus called a so-called stepper is known. This stepper reduces a pattern image formed on an original plate, for example, a reticle (or a mask) with a projection lens while step-moving a substrate, for example, a semiconductor wafer under a projection lens, and reduces the pattern image at a plurality of positions on one wafer. Are sequentially exposed.

The stepper is considered to be the mainstream of the aligner (exposure apparatus) from the viewpoint of the performance of the resolution and the overlay accuracy.

FIG. 3 shows an example of mounting a structure and an XY stage in a conventional aligner.

1, reference numeral 1 denotes an illuminating unit for illuminating a reticle pattern, 2 denotes a reticle having a pattern to be transferred, 3 denotes a projection lens for projecting the reticle pattern onto a wafer, and 4 denotes a lens barrel support plate that supports the projection lens 3. , 16a is a light emitting section of a focus detecting section for measuring the distance between the focus of the projection lens 3 and the wafer, 16b is a light receiving section of the focus detecting section,
6 is an interferometer for controlling the position of the stage, 9 is the top stage, 10 is the X stage, 11 is the Y stage, and 17 is the X stage.
Reference numeral 18 denotes a DC motor for driving the stage, reference numeral 18 denotes a DC motor for driving the Y stage, reference numeral 61 denotes a support surface plate on which the entire projection lens 3 and XY stages 10 and 11 are mounted, reference numeral 62 denotes a frame, and reference numeral 63 denotes a servo mount.

Semiconductor wafers processed by the aligner having such a configuration tend to use large-diameter and large-sized semiconductor wafers in order to increase the area and cost of semiconductor elements. Currently, the wafer size is φ6 '(φ150mm)
Is the mainstream, but from 1990, φ8 '(φ200mm) is expected to become the mainstream.

On the other hand, semiconductor devices (especially DRAMs) have been highly integrated from the 4M (mega) bit era to the 16M (mega) bit era, and the line width has also become finer. Therefore, there is a strong demand for higher-precision alignment, a higher-precision XY stage, higher throughput, and the like.

[Problems to be Solved by the Invention] However, the conventional stepper structure in which the conventional exposure apparatus for φ3 ′ to φ6 ′ is simply increased in size to φ8 ′ and the XY stage is directly fixed to the support surface plate 61 in FIG. According to this, the following problems occur.

a) To increase the stroke of the XY stages 9, 10, and 11,
In order to guarantee the same or higher precision as that of the stage before the stroke up, it is necessary to increase the guide rigidity. Further, in order to satisfy the requirement of the high-precision stage described above, the stage weight has to be further increased more than simply the weight increase due to the stroke up. As a result, an increase in the excitation force due to the acceleration of the stage movement, and a decrease in the relative rigidity of the lens-supporting structure due to an increase in the weight of the projection lens causes a vibration problem, which causes the following problems.

The reinforcement of the structure increases the size and cost of the device.

Since the exposure and alignment operations cannot be performed until the structural system is shaken, productivity is reduced.

b) On the other hand, an increase in the weight of the stage statically increases the moving load, which causes a problem that the attitude of the apparatus changes depending on the position of the XY stage. Therefore, the following problems occur.

The alignment accuracy deteriorates.

In order to prevent a decrease in productivity, it is necessary to instantaneously set the apparatus attitude to a constant attitude. Therefore, it is necessary to improve the servo mounting ability in the conventional configuration shown in FIG. 3, which leads to an increase in cost.

The control mechanism becomes large and complicated in order to make the entire apparatus having the increased weight have a constant attitude, and it becomes difficult to perform high-precision attitude control.

And other problems occur.

The present invention has been made in view of the above-described problems of the related art, and has as its object to realize an inexpensive, high-accuracy, high-throughput exposure apparatus that realizes prevention of apparatus vibration with a compact configuration.

[Means and Actions for Solving the Problems] In order to achieve the above object, in the structure of the main body structure of the exposure apparatus according to the present invention, the XY stage base is hung from the barrel base, and the main body mount is a barrel. It features a structure that supports the surface plate.

With this configuration, first, the mount position can be arranged near the center of gravity of the main body, and the damping performance against the vibration of the main body due to the movement of the stage is improved. Also, the vibration isolation performance against vibration from the outside such as the floor is improved. Furthermore, since the center of rotation in the vibration of the main body is near the center of gravity of the main body, it is easy for the separate exposure light source (eg, excimer laser) to arrange the incident position at the center of rotation of the main body, which is advantageous for the exposure optical system. Become. As a second effect, the relative vibration between the stage base and the barrel base is reduced by the fact that the object to be vibrated is replaced by the stage base from the barrel base, which reduces the weight of the two base connection members. By increasing the dynamic rigidity, the relative vibration damping performance is improved.

From the above, the alignment accuracy and the printing accuracy can be improved without sacrificing the throughput.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view (partially shown) of a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an illumination unit for illuminating a reticle, 2 denotes a reticle having a pattern to be transferred, 3 denotes a projection lens for projecting a pattern formed on the reticle onto a wafer, and 4 denotes a lens barrel that supports the projection lens. Surface plate 5, mount for supporting lens barrel surface plate 4, 6 for Y
Y stage movable in the X direction, 7 is an X stage movable in the X direction, 8 is a top stage mounted on the X stage 7 and capable of moving and rotating in the Z, θ, α and β directions. is there. 9 is each stage 6-8
A stage base 10 supports the stage base 9. As the mount 5, a normal air mount or active mount can be used. 11 is a laser interferometer for detecting the position of the XY stage, 12 is a DC servo motor for driving the Y stage 6, and 13 is a DC servo motor for driving the X stage 7. Here, the suspension member is integrated with the lens barrel base to achieve high rigidity.

 Next, the operation will be described.

Among the vibrations of the main body, the one with the worst damping is generally a coupled vibration mainly including a rotational motion of α and β and a parallel motion of X, Y and Z (referred to as rocking). If the stage moves step by step, this locking will be noticeable. For example, looking at the acceleration in the X direction of the projection lens when the stage makes X steps, the conventional technique is as shown by a solid line graph in FIG. 2 (a). However, by supporting the vicinity of the center of the body weight according to the present invention, the damping performance of the main body vibration is improved, as shown in FIG. 2 (b).

FIG. 4 is a view showing another embodiment of the present invention, wherein 1 is an illuminating section for illuminating a reticle 2, 2 is a reticle having a pattern to be transferred, and 3 is a pattern projected on a reticle onto a wafer. 4 is a lens barrel base that supports the projection lens, 5 is an air mount or active damper that supports the entire apparatus, 6 is a Y stage movable in the Y direction, and 7 is supported by the Y stage 6. And an X stage movable in the X direction, 8 is a top stage mounted on the X stage 7 and having a function of moving and rotating in the Z, θ, α and β directions, and 9 is a stage 6 to 8 A stage base for supporting, 10 is a stage base supported by the mount 5 and supporting the stage base 9, 11 is a laser interferometer for detecting the position of the XY stage,
Reference numerals 12 and 13 denote DC servo motors for driving the Y stage 6 and the X stage 7, respectively. Here, both the lens barrel base 4 and the stage base 10 have a structure supported by the mount 5.

The operation and effects are the same as those of the above-described embodiment. However, in the embodiment of FIG. 4, the stage base 10 receives a variable load accompanying the movement of the XY stage compared to the embodiment of FIG. Of the projection lens mounting surface can be reduced. In addition, the assemblability can be improved.

[Effect of the Invention] As described above, according to the present invention, the damping performance of the main body vibration is improved by a simple structural change in which the stage base is suspended from the barrel base and the barrel base is mounted. Can be done. In addition, since the distance between the stage base and the barrel base can be shortened structurally, when the hanging member is integrated with the barrel base, high rigidity can be achieved, and the printing accuracy is improved.

[Brief description of the drawings]

1 is an overall configuration diagram of an embodiment of the present invention, FIGS. 2 (a) and 2 (b) are displacement response diagrams showing vibration damping characteristics in a conventional structure and the structure of the present invention, respectively, and FIG. 3 is a conventional exposure apparatus. FIG. 4 is an overall configuration diagram of another embodiment of the present invention. 1: Lighting unit, 2: Reticle, 3: Projection lens, 4: Barrel platen, 5:
Mount, 6: Y stage, 7: X stage, 8: Top stage, 10: Stage surface plate.

Claims (4)

(57) [Claims] 1. A lens barrel base for supporting a projection optical system, a stage for mounting and moving a substrate to be exposed, a stage base for supporting the stage, and a support for the lens barrel on an installation floor. An exposure apparatus, comprising: a mounting means for mounting the stage base, and suspending and supporting the stage base from the barrel base. 2. The apparatus according to claim 1, wherein the weight of said stage base is supported by said barrel base, and said stage base is indirectly supported by said mounting means via said barrel base. 2. The exposure apparatus according to 1. 3. An exposure apparatus according to claim 1, wherein said stage base is supported by said mounting means substantially directly together with said lens barrel base. 4. An exposure apparatus according to claim 1, wherein a connecting portion between said mounting means and said lens barrel base is located at a position higher than said stage base.