JPH0527191A - Production of vibrator plate - Google Patents

Abstract

PURPOSE:To allow the production of the vibrator plate used for a miniature optical scanner, etc., by simple stages without generating work strains, etc., by machining, etc. CONSTITUTION:After a film 22 consisting of silicon nitride, etc., is formed on the surface of a single crystal silicon substrate 21, this film 22 is patterned to form an etching protective film 23 having the shape of the vibrator plate 2. The single crystal silicon substrate 21 is then etched from both the side of the etching protective film 23 and the surface on the side opposite therefrom, by which the vibrator plate 2 is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a vibrator plate. Specifically, it relates to a method for manufacturing a vibrator plate used for an optical scanner or the like.

[0002]

[Background technology]

(Prior Art) As optical devices such as laser beam printers and bar code readers are becoming smaller and lighter, various optical parts are required to be lighter and shorter.

Among these optical components, the optical scanner has a structure in which a regular polygonal polygon mirror is driven by a DC servo motor, and it is difficult to miniaturize the laser beam printer. It was a neck.

(Explanation of Transducer Plate) Therefore, prior to the present invention, the applicant of the present invention has proposed a microminiature optical scanner utilizing the elasticity of the oscillator plate (Japanese Patent Application No. 209804).

An example of this ultra-compact optical scanner is shown in FIG. This optical scanner 1 is composed of a thin plate-shaped vibrator plate 2 and a drive source 3 that generates a minute vibration such as a piezoelectric vibrator or a magnetostrictive vibrator. The vibrator plate 2 is integrally provided with a vibration input unit 5 for applying a vibration from the driving source 3 to a lower end of an elastically deforming portion 4 having a narrow width or a shaft shape, and an upper end of the elastically deforming portion 4 is integrally provided. Is integrally provided with a scanning unit 6 which is mirror-finished so as to reflect the laser beam α. Here, the elastically deformable portion 4 is capable of a torsional deformation mode in which it is torsionally deformed around the axis P and a bending deformation mode in which it is bent and deformed along the axis P. The scanning portion 6 is formed in an unbalanced shape with respect to the axis P of the elastically deforming portion 4, and the weight portion 7 is formed at a portion distant from the axis P of the elastically deforming portion 4.

Therefore, the drive source 3 is changed to the vibrator plate 2
When a minute vibration having a drive frequency equal to the resonance frequency of the elastic deformation portion 4 in the torsional deformation mode is applied, the minute vibration is amplified and the elastic deformation portion 4 vibrates in the torsional deformation mode.
The scanning unit 6 rotates about the axis P.

On the other hand, when a minute vibration having a drive frequency equal to the resonance frequency of the bending deformation mode of the elastic deformation portion 4 is applied from the driving source 3 to the vibrator plate 2, the minute vibration is amplified and the elastic deformation portion 4 is bent and deformed. The scanning unit 6 vibrates in the mode, and the scanning unit 6 rotates about an axis Q orthogonal to the axis P.

Therefore, when the scanning unit 6 which is mirror-finished is irradiated with the laser beam α emitted from the semiconductor laser element while rotating the scanning unit 6 around the axis P or the axis Q, the laser beam α is scanned. The light is reflected by the scanning unit 6 and is scanned at a scan angle twice the rotation angle θ _T or θ _B of the scanning unit 6. Further, by simultaneously rotating the scanning unit 6 in both directions, the laser beam α
Can be scanned two-dimensionally (planar).

(Regarding the method of manufacturing the vibrator plate at the beginning of development) The performance of the optical scanner is determined by the material of the vibrator plate and the processing accuracy of the elastically deforming portion.

Therefore, at first, it was attempted to manufacture the vibrator plate by machining a thin stainless plate, but it was not possible to obtain sufficient characteristics due to the processing strain of the elastically deformed portion.

Next, it was considered to manufacture the vibrator plate 2 by applying a semiconductor manufacturing process to a semiconductor substrate such as a single crystal silicon (Si) substrate. According to this method, the vibrator plate 2 could be accurately manufactured without causing processing strain in the elastically deformable portion.

3A to 3D show a process of manufacturing the vibrator plate 2 using the single crystal silicon substrate 11.
This is a process of etching or polishing the single crystal silicon substrate 11 from the lower surface and thinning the single crystal silicon substrate 11 until it becomes equal to the thickness of the vibrator plate 2 (FIG. 3).
(A); The scraped portion of the back surface of the single crystal silicon substrate 1 is represented by a broken line. ) And a single crystal silicon substrate 11
A step of forming a coating film 12 of silicon nitride or the like on the surface of the substrate (FIG. 3B), and a step of patterning the coating film 12 by photolithography or the like to form an etching protection film 13 having substantially the same shape as the vibrator plate 2. , The single-crystal silicon substrate 11 is KOH with the etching protection film 13 as a mask.
A step of selectively etching the upper surface side of the single crystal silicon substrate 11 from the etching protection film 13 (FIG. 3C), and the etching protection film 13
Of peeling off the substrate to obtain the vibrator plate 2 (FIG. 3D)
It consists of

However, according to such a method of manufacturing the vibrator plate, a complicated manufacturing process is required, so that it takes time to manufacture the vibrator plate from the semiconductor substrate, and mass production and cost reduction are required. I had a problem with.

Further, since the thickness of the vibrator plate is made by etching or polishing the semiconductor substrate from the back surface side, the control of the etching rate is complicated,
Since it was necessary to alternately perform plate thickness inspection and polishing, there was a large variation in the thickness of the vibrator plate, and the reproducibility of the vibrator plate was low.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical background, and an object thereof is to manufacture a vibrator plate having good accuracy from a semiconductor substrate in a short time. To provide a way to do.

[0016]

According to the method of manufacturing a vibrator plate of the present invention, an elastic deformation portion having at least one elastic deformation mode, a vibration input portion provided at one end of the elastic deformation portion, and an elastic deformation portion. Of the vibrator plate having a drive unit provided at the other end of the vibrator plate, and converting the minute vibration applied to the vibration input unit into a predetermined elastic deformation mode by the elastic deformation unit to rotate the drive unit. In the manufacturing method, an etching protection film having a pattern substantially matching the shape of the vibrator plate is formed on the surface of the semiconductor substrate, and both surfaces of the surface of the semiconductor substrate opposite to the surface on which the etching protection film is formed are formed. The feature is that the vibrator plate is obtained by simultaneously etching.

Further, it is preferable that the semiconductor substrate for obtaining the vibrator plate has a thickness approximately twice the plate thickness of the vibrator plate.

[0018]

In the present invention, after the etching protection film is formed on the surface of the semiconductor substrate, the etching is simultaneously performed from both the surface of the semiconductor substrate on which the etching protection film is formed and the opposite surface. The step of obtaining the shape of the vibrator plate by selective etching and the step of obtaining the plate thickness of the vibrator plate can be performed at the same time, and the number of steps for manufacturing the vibrator plate can be reduced. Therefore, the manufacturing process of the vibrator plate is simplified, the vibrator plate can be manufactured in a short time, mass productivity is improved, and the manufacturing cost is reduced.

Further, since the vibrator plate is manufactured by etching the semiconductor substrate or the like, it does not cause processing strain in the elastically deformed portion as in the case of mechanical processing, and has excellent vibration characteristics and reliability. It is possible to manufacture a vibrator plate with good accuracy.

Further, the thickness of the vibrator plate, which influences the characteristics of the vibrator plate, can be accurately obtained by using a semiconductor substrate having a thickness approximately twice as large as that of the vibrator plate, without requiring troublesome control. The desired thickness of the vibrator plate can be obtained.

[0021]

1 (a), 1 (b), 1 (c) and 1 (d) show manufacturing steps of a vibrator plate 2 according to an embodiment of the present invention. Figure 1
A method of manufacturing the vibrator plate 2 will be described below. First, the single crystal silicon substrate 21 is subjected to surface treatment such as degreasing and cleaning, and then a coating film 22 of silicon nitride or the like is formed on the upper surface (mirror surface) of the single crystal silicon substrate 21 by a chemical vapor deposition (CVD) method or a sputtering method. (FIG. 1 (a)). At this time, if the single crystal silicon substrate 21 having a thickness equal to twice the plate thickness required for the vibrator plate 2 is used, the thickness control of the vibrator plate 2 can be easily performed. For example,
When the thickness of the vibrator plate 2 is 150 μm,
The thickness of the single crystal silicon substrate 21 may be 300 μm.

Then, the coating film 22 of silicon nitride or the like is patterned by photolithography and reactive ion etching (RIE), and an etching protection film 23 having a pattern of the same shape as that of the vibrator plate 2 is formed on the single crystal silicon substrate 21. It is provided on the upper surface (FIG. 1 (b)).

After patterning the etching protection film 23, the single crystal silicon substrate 21 is, for example, KO having a concentration of 25%.
It is immersed in the H solution and etched. At this time, as shown in FIG. 1C, the single crystal silicon substrate 21 is selectively etched from the upper surface side through the mask of the etching protection film 23 and simultaneously etched from the lower surface side.
Then, the shape of the oscillator plate 2 is obtained by etching from the upper surface side, and the lower surface of the single crystal silicon substrate 21 is ground so as to have the thickness of the oscillator plate 2 by etching from the lower surface side. Thus, when the single crystal silicon substrate 21 other than the region covered by the etching protection film 23 is completely etched, the shape of the vibrator plate 2 is taken out from the single crystal silicon substrate 21 (the portion removed by etching is 1C, which is indicated by a broken line.) At this time, since the etching depth from the upper surface side and the etching depth from the lower surface side are equal, the plate thickness of the vibrator plate 2 is the original thickness of the single crystal silicon substrate 21. It becomes 1/2 of.

After confirming that the single crystal silicon substrate 21 other than the region covered with the etching protection film 23 is completely etched, the single crystal silicon substrate 21 is thoroughly washed with water and dried, and then, The etching protection film 23 on the surface is removed to obtain a vibrator plate 2 having a desired plate thickness and shape as shown in FIG.

According to such a manufacturing process, as shown in FIG.
In the step of (1), the step of selectively etching the single crystal silicon substrate 21 to obtain the shape of the oscillator plate 2 and the step of etching the entire lower surface of the single crystal silicon substrate 21 to adjust the plate thickness to a desired value are performed. You can
The manufacturing process of the vibrator plate 2 can be simplified. At the same time, it becomes easy to control the plate thickness of the vibrator plate 2.

Therefore, the vibrator plate 2 can be manufactured in a short time, the mass productivity and the reproducibility are excellent, and the accuracy of the vibrator plate 2 is good. Further, since processing distortion does not occur, reliability is also improved. In particular, it has been confirmed that the processing accuracy in the thickness direction of the vibrator plate 2 is within ± 10 μm, and the processing method is also excellent in thickness controllability.

In the above embodiment, the single crystal silicon substrate is used as the material (wafer) for manufacturing the vibrator plate, but any material that can be processed by the semiconductor manufacturing process may be used, for example, a compound semiconductor substrate such as GaAs. May be used. Further, the vibrator plate is not limited to the one having the elastic vibration mode in the two-axis directions, and may be the one having the elastic vibration mode only in the one-axis direction and the scanning unit rotating only in the one direction. Further, this vibrator plate is used not only as an optical scanner as shown in FIG. 2, but also by attaching a light emitting element such as a light emitting diode or a light receiving element such as a photodiode to the scanning section, a light projecting section or an optical element having a scanning property. It has various applications such that it can also be used as a detector or the like.

[0028]

According to the present invention, since the step of forming the shape of the vibrator plate and the step of obtaining the thickness of the vibrator plate can be carried out at the same time, the manufacturing step of the vibrator plate can be simplified. Therefore, the vibrator plate can be formed from the semiconductor substrate in a short time, mass productivity is improved, and the manufacturing cost of the vibrator plate can be reduced.

Further, since there is no machining strain in the vibrator plate due to mechanical processing, the characteristics and reliability of the vibrator plate are improved, and the vibrator plate with good accuracy can be manufactured.

Furthermore, the thickness of the vibrator plate can be easily controlled by the thickness of the original semiconductor substrate, and the desired vibrator plate thickness can be obtained with high precision without complicated control.

[Brief description of drawings]

1A, 1B, 1C and 1D are perspective views showing a method of manufacturing a vibrator plate according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an optical scanner using a vibrator plate.

3 (a), (b), (c) and (d) are perspective views showing a method of manufacturing a vibrator plate, which was carried out before the idea of the present invention.

[Explanation of symbols]

2 oscillator plate 4 Elastic deformation part 5 Vibration input section 6 Scan section 21 Single crystal silicon substrate 23 Etching protection film

Claims (2)

[Claims] 1. An elastic deformation part having at least one elastic deformation mode; a vibration input part provided at one end of the elastic deformation part; and a drive part provided at the other end of the elastic deformation part. A method of manufacturing a vibrator plate, wherein microvibration applied to an input part is converted into a predetermined elastic deformation mode by an elastic deformation part to rotate a drive part, wherein the vibrator plate is formed on a surface of a semiconductor substrate. Is formed by forming an etching protection film having a pattern substantially corresponding to the shape of (1) and simultaneously etching both the surface of the semiconductor substrate on which the etching protection film is formed and the surface on the opposite side to obtain an oscillator plate. Method for manufacturing vibrator plate. 2. The plate thickness of the target vibrator plate is approximately 2
The method of manufacturing a vibrator plate according to claim 1, wherein a semiconductor substrate having a double thickness is used.