JPH0513013Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fine movement linear stage, particularly to a fine movement linear stage having a positioning resolution of 1 μm or less.

[Technological environment]

In recent years, the density of integrated circuits has been increasing year by year, and the width of the patterns that make up the circuits is now increasing.
The size has been reduced to around 1.2 μm. Therefore, in exposure equipment that is a manufacturing machine for integrated circuits, a positioning accuracy of 0.1 μm or less is required for alignment of a wafer and a mask.

[Conventional technology]

Conventional linear stages have been made by combining linear guides such as sliding guides such as dovetail grooves, rolling guides using ball bearings and needle bearings, and sliding or rolling feed screws to create linear movement stages.

These stages suffer from bumps and slips that are characteristic of sliding and rolling, making it difficult to achieve positioning accuracy of 1 μm or less.

Therefore, conventional linear movement stages are now equipped with a coarse movement stage that performs positioning from 1 to 5 μm, and a fine movement stage with a resolution of 0.01 μm on top of that to share the functions. was.

As fine movement linear guides used in fine movement stages, elastic guides, which are essentially free of backlash, sticks, and slips, are increasingly being used because the total movement distance is only about 10 μm.

FIG. 4 is a conceptual diagram of a parallel plate spring that has been used in measuring instruments as a typical example of elastic guide.
In the figure, a fixed part 1 and a movable part 2 are fixed via two parallel leaf springs 6, 6' and a presser plate 7.
When an external force B shown by the arrow shown in the figure is applied to the movable part 2, the two parallel leaf springs 6 and 6' are elastically deformed as shown in Fig. 5, and the movable part 2 can perform linear motion. . This principle of parallel leaf springs has been used for a long time because it is inexpensive and allows smooth movement to be easily obtained when the amount of movement is small.

However, this parallel leaf spring has problems such as skewing of the motion trajectory and hysteresis due to imperfections such as slippage of the fastening portion that occurs at the portion where the leaf spring is fixed.

Figure 2 shows a fine movement linear guide (Utility Application No. 60-032760) devised previously by the present inventor. A fixed part 1 and a movable part 2 are connected by a flexible part 3, which is two sets of parallel leaf springs, and are made integrally. With this fine movement linear guide, there are no imperfections typical of screw fastening, so
It provides a smooth motion trajectory with no static slip or hysteresis.

On the other hand, small linear motors and piezoelectric elements have been used as actuators that generate minute displacements. In particular, piezoelectric elements are attracting a lot of attention because they can easily generate a resolution as small as 0.01 μm or less and generate extremely little heat.

FIG. 3 shows a conventional fine movement linear stage using the fine movement linear guide shown in FIG. 2 and a piezoelectric element.
It includes a fine linear guide, a piezoelectric element 5, a hemisphere 9, a set screw 10 and a tension spring 11. Here, when a voltage is applied to the piezoelectric element, displacement occurs, and the movable part 2 is pushed and moved through the hemisphere 9.

[Problem that the invention attempts to solve]

In the conventional fine movement linear stage described above, the method of connecting the fixed part, piezoelectric element, and movable part is to push the back of the piezoelectric element from the fixed part with a push screw, and use a tension spring to draw the gap between the movable part and the fixed part. It's tottering. Since a hemisphere is attached to the tip of the piezoelectric element, there is point contact between the piezoelectric element and the fixed part. This is because minute displacements generated by the piezoelectric element are transmitted correctly without being absorbed by the gaps.

However, in applications where a load is applied to the movable part, minute elastic deformation may occur in the point contact part and the push screw part, so the disadvantage is that the displacement generated by the piezoelectric element is reduced or absorbed. .

[Means for solving problems]

The fine movement linear stage of the present invention has a movable part in the center of a U-shaped fixed part, and the fixed part and the movable part are two sets of parallel thin-walled flexible parts located at symmetrical positions of the U-shape. The fixed part and the movable part are further axially symmetrically coupled at the U-shaped bottom of the fixed part by two pressurizing members having a plurality of alternating cuts from left and right sides, and 2 above of fine movement linear guide where all components are integrated
It is constructed by press-fitting a piezoelectric element between two pressurizing members.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

The fine movement linear stage shown in Figure 1 has a U-shaped fixed part 1.
, a movable part 2 located in the center thereof, a fine movement linear guide consisting of two sets of parallel flexible parts 3 and two pressurized parts 4, the bottom of the U-shaped fixed part 1 and the movable part 2 and a piezoelectric element 5 press-fitted between the two.

When a voltage is applied to the piezoelectric element 5, the length changes △
Extends. This displacement overcomes the pressurization of the pressurization section 4 and pushes the movable section 2. Since the movable part 2 is supported by two sets of parallel flexible parts 3, it can perform linear motion without causing left and right wobbling.

Since the piezoelectric element 5 is a laminated piezoelectric ceramic actuator, it has strong rigidity in the displacement direction A, which is unique to ceramics. The pressurizing part 4 has a plurality of thin grooves cut alternately from both sides. If the free length of the pressurized part 4 is made shorter than the length of the piezoelectric element by a predetermined amount Δ', by press-fitting the piezoelectric element 5 into the position shown in FIG. Displace. As a result, the piezoelectric element 5
This means that pressurization is applied by the two pressurization sections 4. As an example, the width is 12mm, the length is 22mm, and the plate thickness is 6mm.
3 grooves with a width of 0.5 mm and a depth of 8 mm are made at a pitch of 3 mm in the steel.
With this provision, a spring constant of 0.56 Kg/μm (actual value) can be obtained. When a displacement of 40 μm is applied as Δ′, the two pressurizing parts 4 apply a pressurizing force of 44.8 kg to the piezoelectric element 5.

[Effect of idea]

In the fine movement linear stage of the present invention, the piezoelectric element and the linear guide are connected with high rigidity by applying large pressurization without any gaps, so mechanical errors such as bumps and lost motion that are likely to occur when piezoelectric elements are installed are avoided. It has the effect of being able to completely remove. Moreover, since both the piezoelectric element and the fastening portion have high rigidity, it is possible to achieve a stage that is resistant to external disturbances.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the present invention;
The figure is a perspective view showing an example of a conventional example, FIG. 3 is a perspective view showing an example of use of the fine movement linear guide shown in FIG. 2, and FIG.
5 and 5 are perspective views showing the operation of the flexible portion shown in FIG. 2. DESCRIPTION OF SYMBOLS 1... Fixed part, 2... Movable part, 3... Flexible part, 4... Pressurized part, 5... Piezoelectric element, A... Displacement direction, B... External force.

Claims (1)

[Scope of utility model registration request] There is a movable part in the center of the U-shaped fixed part, and the fixed part and the movable part are connected to each other at symmetrical positions of the U-shape by two sets of parallel thin-walled flexible parts,
The fixed part and the movable part are further axially symmetrically connected at the U-shaped bottom of the fixed part by two pressurizing members having a plurality of alternating cuts from left and right sides, and all of these structures A fine movement linear stage in which a piezoelectric element is press-fitted between the two pressurizing members of the fine movement linear guide whose elements are integrally made.