JP2002040670A - Resist exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist exposure device, capable of forming arbitrary patterns without using a mask, applying very small corrections within the same patterns, preventing cellularization of the patterns and making utilization of light effective. SOLUTION: This device has a light source 4; a substrate which is coated with photosensitive resist on its front surface; a DLP element 5, which is integrated with multiple sheets of very small micromirrors and switches the inclinations of the individual micromirrors to two directions according to digital input signals and an exposure control means 7, which outputs digital signals to the DLP element according to the prescribed exposure patterns, reflects part of the light of the light source toward the resist by the DLP element to expose the resist and reflects the remaining part of the light toward the areas exclusive of the resist. The inclinations of the respective micromirrors of the DLP element 5 are switched by the digital signals, by which the resist is exposed to a prescribed patterns.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist exposure apparatus used for forming a predetermined electrode pattern on a substrate by photolithography.

[0002]

2. Description of the Related Art Conventionally, a photoresist method has been used as a method of forming a vibrating electrode on a piezoelectric substrate. In this method, a photosensitive resist is applied over the entire surface of a substrate having a conductive film formed on the surface, a mask of an electrode pattern is placed thereon, and exposure is performed. After that, the substrate is put in a developing solution to form a resist of a predetermined pattern, and further, the substrate on which the resist is formed is put in an etching solution, and the conductive film in a portion without the resist is removed, and then the resist is removed. And a method for obtaining a predetermined electrode pattern.

In this method, since one fixed mask is required for one pattern, it is necessary to change the mask if the pattern changes, which has the disadvantage of increasing the cost. In addition, there is a large time loss during setup when replacing the mask. Further, the oscillation frequency of the piezoelectric body fluctuates due to the variation of the material, but fine correction can be performed by the electrode pattern. However, a fixed mask cannot perform such a minute correction in the same pattern.

[0004]

Therefore, a method of forming a pattern using a liquid crystal mask instead of a fixed mask has been proposed (for example, Japanese Patent Application Laid-Open No. Hei 7-152139). In the case of a liquid crystal mask, an arbitrary pattern can be formed with one mask, and there is an advantage that a minute correction can be performed within the same pattern. However, in the case of liquid crystal, the aperture ratio of the cell is low, the pattern becomes a cell, and the effective utilization of light is low.

Therefore, an object of the present invention is to form an arbitrary pattern without using a mask, to perform minute correction within the same pattern, and to prevent the pattern from being made into cells. Another object of the present invention is to provide a resist exposure apparatus capable of effectively utilizing light.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a light source, a substrate having a surface coated with a photosensitive resist, and a large number of minute micromirrors are integrated. A digital signal is output to a DLP element that switches the tilt of each micromirror in two directions according to an input signal and a DLP element according to a predetermined exposure pattern, and a part of light from a light source is directed toward the resist by the DLP element. There is provided a resist exposure apparatus comprising: an exposure control means for reflecting the resist to expose the resist and reflecting the remaining light to a portion other than the resist.

The present invention relates to an apparatus for exposing a resist pattern on a substrate by photolithography, and solves the conventional problems by using a DLP element instead of a conventional fixed mask or liquid crystal mask. DL
P (Digital Light Processing) element is a DMD (Degi
tal Micromirror Device), which integrates a large number of micromirrors (for example, hundreds of thousands) into a single chip, and turns on / off digital input signals to individual micromirrors, thereby enabling individual micromirrors. The direction of the light is switched by tilting the direction of the mirror by about ± 10 degrees. The exposure control means inputs a digital signal to the DLP element so as to switch the inclination of each micromirror according to a predetermined exposure pattern. That is,
Micromirrors that reflect light from a light source toward the resist to expose the resist and micromirrors that reflect light to portions other than the resist are classified. By controlling the digital signal in this way, an arbitrary pattern can be formed with one DLP element, and a minute correction can be applied within the same pattern. Since the DLP element has a very small seam between pixels, it is possible to solve the problem that the pattern is formed into a cell like a liquid crystal mask, and the reflectance is high (about 90% or more). Since it is three times or more and has high light resistance, high output can be obtained with power saving. Therefore, the resist can be sufficiently exposed even with a relatively small light source. Since the individual micromirrors constituting the DLP element are minute (for example, 16 × 16 μm), the cell pitch becomes about の of the liquid crystal mask, and a finer pattern can be formed.

According to a second aspect of the present invention, a piezoelectric substrate having a conductive film formed on its surface is used as the substrate, and the exposure control means corrects the exposure pattern according to the characteristics of the piezoelectric substrate, and corrects the digital pattern corrected by the DLP element. It is good to output a signal. The oscillation frequency of the piezoelectric element fluctuates due to a variation in the material of the piezoelectric body or the like, but can be corrected by modifying the pattern shape of the vibrating electrode. If the exposure apparatus of the present invention is applied, one-to-one for each element according to the characteristics of the piezoelectric body.
In this way, the oscillation frequency can be corrected, and the non-defective product rate can be improved without performing the conventional frequency adjustment step.

The resist exposure apparatus of the present invention can be applied not only to the formation of electrodes on a piezoelectric substrate but also to the formation of wiring on a printed board or the formation of a circuit on a semiconductor. Therefore,
The resist can be used for various applications such as etching of an insulating film, formation of a diffusion layer, and ion implantation as well as etching of an electrode film.

[0010]

1 and 2 show an example of a resist exposure apparatus according to the present invention. This exposure apparatus includes a light source 4,
It comprises a DLP element 5, an optical system 6, and a controller (exposure control means) 7 for controlling the DLP element 5. Light emitted from the light source 4 is reflected by the DLP element 5, passes through the optical system 6, becomes a parallel light beam, and is emitted to the object W. D
As shown in FIG. 2, the LP element 5 integrates a large number of micro-mirrors 5a and 5b on one chip, and turns ON / OFF digital input signals to the individual micro-mirrors 5a and 5b by the controller 7. Switching the tilt angle of each micro mirror 5a, 5b to two positions,
The light reflection direction is switched between two directions (light beams 4a and 4b). The controller 7 stores a reference exposure pattern in advance, and has a function of correcting the reference pattern with a correction value and outputting a digital signal to the DLP element.

FIG. 3 shows an example in which the resist exposure apparatus is used for manufacturing a piezoelectric resonator. (A) shows a step of preparing the piezoelectric substrate 1. A conductive film 2 is formed on the surface of the piezoelectric substrate 1. The conductive film 2 is formed by a thin film forming method such as sputtering or vapor deposition. In this preparation step, a measuring tool is brought into contact with the front and back of the piezoelectric substrate 1 to measure material characteristics such as a resonance frequency and an anti-resonance frequency. This is because the material characteristics vary from one piezoelectric substrate 1 to another. This measurement data is transferred to the controller 7. (B) shows a step of applying the photosensitive resist 3. That is, the photosensitive resist 3, which changes to be soluble or insoluble in a solvent when exposed to light, is applied to the surface of the piezoelectric substrate 1 by a rotation method, a method of pressing a film resist with a roll, or the like. (C)
Indicates an exposure step. The light emitted from the light source 4 is DLP
The light is reflected by the element 5, passes through the optical system 6, becomes a parallel light, and irradiates the resist 3 formed on the surface of the piezoelectric substrate 1. Material characteristics data of the piezoelectric substrate 1 measured in the preparation step (a) is input to the controller 7, and based on the measured data, the controller 7 corrects an electrode pattern (exposure pattern) having a desired oscillation frequency. Digital signal corresponding to each pixel of the corrected electrode pattern
It is sent to each micro mirror of the element 5. As a result, the individual micromirrors 5a and 5b are switched to the ON position or the OFF position. For example, the micromirror 5a at the ON position reflects the light of the light source 4 toward the resist 3 (light beam 4a), and the micromirror at the OFF position. The mirror 5b reflects toward a portion other than the resist 3 (light beam 4b). Therefore, the resist 3 is subjected to pattern exposure by the light 4a reflected by the micro mirror 5a of the DLP element 5. (D) shows a developing step. That is, the unexposed unexposed resist is removed by a developer to form a resist 3a having a predetermined pattern. (E) shows an etching step in which a portion of the conductive film 2 where there is no resist 3a is removed by an etchant.
(F) shows a resist removing step, in which the resist 3a remaining on the conductive film 2 is removed. As a result, on the piezoelectric substrate 1, the electrodes 2a having an optimum pattern matching the characteristics of each piezoelectric substrate 1 are formed.

As described above, before the exposure step, the piezoelectric substrate 1
Since the material characteristics are measured in advance and the electrode pattern is corrected in accordance with the characteristics, variations in the oscillation frequency due to material variations of the individual piezoelectric substrates 1 can be reduced. Therefore, the frequency adjustment step can be eliminated, and the quality non-defective rate is improved.

FIG. 1 shows an example in which one vibration electrode 2a is formed on one piezoelectric substrate 1 for the sake of simplicity. However, in practice, a large number of vibration electrodes 2a are formed on the piezoelectric substrate 1. Is formed. Therefore, the DLP element 5 is controlled to a pattern that allows a large number of electrodes 2a to be formed by one exposure. In recent years, a high-resolution DLP device having as many as 1280 × 1024 micromirrors has been developed, and even a large piezoelectric substrate (mother substrate) can be exposed in one process.

In the above embodiment, an example was described in which the present resist exposure apparatus was used to form the predetermined electrode pattern 2a on the piezoelectric substrate 1, but the present invention is not limited to this. For example, it can be used for forming pattern wiring on a printed circuit board, forming a diffusion layer of a semiconductor device, and the like. In particular,
The resist exposure apparatus of the present invention is suitable for forming a pattern while correcting it appropriately according to the characteristics of the substrate instead of forming a fixed pattern.

[0015]

As is apparent from the above description, claim 1
According to the method described in (1), the resist pattern is exposed on the substrate by using the DLP element. Therefore, by controlling the digital input signal to the DLP element, one DLP element can be used to expose an arbitrary pattern. Can be formed, and minute correction can be performed within the same pattern. Further, since the DLP element has a very small seam between pixels, the problem that the pattern is formed into a cell like a liquid crystal mask can be solved. In addition, since the reflectance is high, the effective light utilization rate is three times or more of the liquid crystal mask. And high light resistance, so high power can be obtained with low power consumption. Therefore, the resist can be sufficiently exposed even with a relatively small light source. Further, since the individual micromirrors constituting the DLP element are minute, the cell pitch is about 1/3 of the liquid crystal mask, and a finer pattern can be formed. Therefore, a highly accurate and highly reliable exposure apparatus that does not use a mask can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a resist exposure apparatus according to the present invention.

FIG. 2 is an enlarged principle view of a DLP element of the resist exposure apparatus shown in FIG.

FIG. 3 is a process chart in which the resist exposure apparatus shown in FIG. 1 is used for forming electrodes of a piezoelectric resonator.

[Explanation of symbols]

 Reference Signs List 1 piezoelectric substrate 2 conductive film 3 resist 4 light source 5 DLP element 6 optical system 7 controller

Claims (2)

[Claims] 1. A light source, a substrate having a surface coated with a photosensitive resist, and a large number of micromirrors are integrated.
A digital signal is output to the DLP element that switches the direction and a DLP element according to a predetermined exposure pattern, and the DLP element reflects a part of the light of the light source toward the resist to expose the resist, and removes the rest of the light. A resist exposure apparatus, comprising: an exposure control unit that reflects light to a portion other than the resist. 2. The substrate according to claim 1, wherein said substrate is a piezoelectric substrate having a conductive film formed thereon, and said exposure control means corrects an exposure pattern in accordance with characteristics of said piezoelectric substrate and outputs a corrected digital signal to a DLP element. The resist exposure apparatus according to claim 1, wherein: